Caracterización bioinformática y producción de L-asparaginasa de Bacillus sp. M62 aislado de las salinas de Maras, Cusco, Perú

El objetivo del estudio fue realizar la caracterización bioinformática, así como optimizar la producción de L-asparaginasa extracelular de Bacillus sp. M62 aislada de las salinas de Maras (Cusco). Para ello, se verificó la producción de L-asparaginasa mediante el viraje del medio M9 modificado con azul de bromofenol 0.0075%, pH 7.4 a 37 °C por 72 h. A la vez, se extrajo el ADN genómico para amplificar los genes ribosómicos 16S y el gen ansA3. La secuencia aminoacídica codificada por el gen ansA3 se predijo mediante análisis bioinformático. La producción de L-asparaginasa intracelular y extracelular se evaluó a diferentes niveles de glucosa, L-asparagina, NaCl y pH en el medio M9 modificado. Adicionalmente, las actividades enzimáticas de L-asparaginasa y L-glutaminasa se determinaron mediante cuantificación del amonio liberado por el método de Nessler. Así, Bacillus sp. M62 produjo el viraje del medio M9 modificado, obtuvo alta similitud y cercanía evolutiva con Bacillus licheniformis, se encontró que el gen ansA3 amplificado codificaba para 319 aa, dentro de la cual se predijo una secuencia patrón del sitio activo (GFVITHGTDTM ) y 15 sitios inmunogénicos. La producción de L-asparaginasa extracelular fue superior a la intracelular, la que se optimizó de 0.37 U/mL (0.24 U/mg) a 2.15 ± 0.39 U/mL (0.63 U/mg). Finalmente, se encontró que Bacillus sp. M62 presenta L-asparaginasa extracelular con mínima actividad de L-glutaminasa.

The aim of this study was to perform bioinformatics characterization and optimize the production of extracellular L-asparaginase from Bacillus sp. M62, isolated from the Maras salt ponds (Cusco). To achieve this, the production of L-asparaginase was verified by the change in color of modified M9 medium, containing 0.0075% bromophenol blue, at pH 7.4 and 37°C for 72 hours. Genomic DNA was extracted to amplify the 16S ribosomal genes and the ansA3 gene. The amino acid sequence encoded by the ansA3 gene was predicted using bioinformatic analysis. The production of intracellular and extracellular L-asparaginase was evaluated at different levels of glucose, L-asparagine, NaCl, and pH in modified M9 medium. Additionally, the enzymatic activities of L-asparaginase and L-glutaminase were determined by quantifying the released ammonium using the Nessler method. Bacillus sp. M62 showed the change in color of the modified M9 medium, high similarity, and evolutionary closeness to Bacillus licheniformis. The amplified ansA3 gene was found to encode for 319 amino acids, with a predicted active site pattern (GFVITHGTDTM) and 15 immunogenic sites. The production of extracellular L-asparaginase was found to be higher than intracellular L-asparaginase and was optimized from 0.37 U/mL (0.24 U/mg) to 2.15 ± 0.39 U/mL (0.63 U/mg). Finally, it was found that Bacillus sp. M62 presents extracellular L-asparaginase with minimal L-glutaminase activity.

Efficient production of L-asparaginase in Bacillus licheniformis by optimizing expression elements and host / 生物工程学报

L-asparaginase (L-ASN) is widely applied in the treatment of malignant tumor and low-acrylamide food production, however, the low expression level hampers its application. Heterologous expression is an effective strategy to increase the expression level of target enzymes, and Bacillus is generally used as the host for efficient production of enzymes. In this study, the expression level of L-asparaginase in Bacillus was enhanced through optimization of expression element and host. Firstly, five signal peptides (SPSacC, SPAmyL, SPAprE, SPYwbN and SPWapA) were screened, among which SPSacC showed the best performance, reaching an activity of 157.61 U/mL. Subsequently, four strong promoters (P43, PykzA-P43, PUbay and PbacA) from Bacillus were screened, and tandem promoter PykzA-P43 showed the highest yield of L-asparaginase, which was 52.94% higher than that of control strain. Finally, three Bacillus expression hosts (B. licheniformis Δ0F3 and BL10, B. subtilis WB800) were investigated, and the maximum L-asparaginase activity, 438.3 U/mL, was reached by B. licheniformis BL10, which was an 81.83% increase compared with that of the control. This is also the highest level of L-asparaginase in shake flask reported to date. Taken together, this study constructed a B. licheniformis strain BL10/PykzA-P43-SPSacC-ansZ capable of efficiently producing L-asparaginase, which laid the foundation for industrial production of L-asparaginase.

Pancreatitis aguda asociada a errores de dosificación de L-asparaginasa en pacientes pediátricos con leucemia linfoblástica aguda en terapia de inducción: estudio exploratorio

Objetivo: explorar si la presencia de errores de dosificación con L-asparaginasa se asocia con la ocurrencia de pancreatitis asociada a L-asparaginasa (PAA) durante la terapia de la inducción a la remisión en pacientes pediátricos con leucemia linfoblástica aguda (LLA). Metodología: se realizó un análisis secundario de una cohorte retro-lectiva en pacientes con LLA que recibieron tratamiento de inducción entre 2015 y 2017. Se consideró un error de dosificación una desviación absoluta mayor a 10% de la dosis requerida. Los casos de PAA se capturaron desde los expedientes. Se calcularon riesgos relativos (RR) con intervalos de confianza para el error de dosificación, subdosis y sobredosis. Resultados: se incluyeron 181 pacientes. Se documentaron 5 (1,1%) casos de PAA y 18 (9,9%) pacientes presentaron errores de dosificación con L-asparaginasa anteriores a la PAA. Se observó una asociación estadísticamente significativa entre la presencia de errores de dosificación (RR=6,04; 1,08-33,77) y la sobre-dosis (RR=10,67; 1,33-85,46). Conclusiones: se observó una posible asociación entre los errores de dosificación con L-asparaginasa y PAA. Sin embargo, se requieren estudios con un enfoque estadístico y un ajuste por variables confusoras.

SUMMARY Aim: To explore whether the presence of dosing errors with L-asparaginase is associated with the occurrence of L-asparaginase-associated pancreatitis (PAA) during remission induction therapy in pediatric patients with acute lymphoblastic leukemia (ALL). Methodology: A secondary analysis of a retrospective cohort was performed in patients with ALL who received induction treatment between 2015 and 2017. An absolute deviation greater than 10% of the required dose was considered a dosage error. PAA cases were captured from the files. Relative risks (RR) with confidence intervals for dosage error, underdose, and overdose were calculated. Results: 181 patients were included. 5 cases of PAA (1.1%) were documented and 18 (9.9%) patients had dosing errors with L-asparaginase prior to PAA. A statistically significant association was observed between the presence of dosage errors (RR=6.04; 1.08-33.77) and overdose (RR=10.67; 1.33-85.46). Conclusions: a possible association between dosage errors with L-asparaginase and PAA was observed. However, studies with a statistical approach and an adjustment for confounding variables are required.

Objetivo: explorar se a presença de erros de dosagem com L-asparaginase está associada à ocorrência de pancreatite associada à L-asparaginase (PAA) durante a terapia de indução de remissão em pacientes pediátricos com leucemia linfoblástica aguda (LLA). Metodologia: uma análise secundária de uma coorte retrospectiva foi realizada em pacientes com LLA que receberam tratamento de indução entre 2015 e 2017. Um desvio absoluto maior que 10% da dose necessária foi considerado um erro de dosagem. Os casos de PAA foram capturados dos arquivos. Os riscos relativos (RR) com intervalos de confiança para erro de dosagem, subdosagem e overdose foram calculados. Resultados: 181 pacientes foram incluídos. 5 casos de PAA (1,1%) foram documentados e 18 (9,9%) pacientes tiveram erros de dosagem com L-asparaginase antes do PAA. Foi observada associação estatisticamente significativa entre a presença de erros de dosagem (RR=6,04; 1,08-33,77) e superdosagem (RR=10,67; 1,33-85,46). Conclusões: foi observada uma possível associação entre erros de dosagem com L-asparaginase e PAA. No entanto, estudos com abordagem estatística e o ajuste para variáveis de confusão são necessários.

Progress in diagnosis and treatment of asparaginase-associated pancreatitis in children with acute lymphoblastic leukemia / 中国小儿急救医学

There is growing evidence of significant clinical and biological benefits of asparaginase (ASP) as a key agent in multidrug combination chemotherapy for pediatric acute lymphoblastic leukemia (ALL), and the drug will continue to be used at higher total doses in intermediate- and high-risk patients.However, high doses of ASP can lead to treatment-related toxicities.Among them, asparaginase-associated pancreatitis (AAP), which is a life-threatening treatment-limiting side effect of chemotherapy, will lead to interruption or complete discontinuation of ASP at grade 3 or 4 in adverse event evaluations, while interruption or discontinuation of ASP may lead to relapse in patients with ALL with an increased risk of remission failure in the case of relapse.Rapid identification and management of AAP will help ensure that patients derive maximum benefit from ASP therapy.This review summarized the diagnosis and management of AAP, possible risk factors, and prudent re-exposure to ASP after the first episode of AAP.

Studies on the recombinant production and anticancer activity of thermostable L- asparaginase I from Pyrococcus abyssi / Estudos sobre a produção recombinante e atividade anticancerígena da L-asparaginase I termoestável de Pyrococcus abyssi

L-Asparaginase catalysing the breakdown of L-Asparagine to L-Aspartate and ammonia is an enzyme of therapeutic importance in the treatment of cancer, especially the lymphomas and leukaemia. The present study describes the recombinant production, properties and anticancer potential of enzyme from a hyperthermophilic archaeon Pyrococcus abyssi. There are two genes coding for asparaginase in the genome of this organism. A 918 bp gene encoding 305 amino acids was PCR amplified and cloned in BL21 (DE3) strain of E. coli using pET28a (+) plasmid. The production of recombinant enzyme was induced under 0.5mM IPTG, purified by selective heat denaturation and ion exchange chromatography. Purified enzyme was analyzed for kinetics, in silico structure and anticancer properties. The recombinant enzyme has shown a molecular weight of 33 kDa, specific activity of 1175 U/mg, KM value 2.05mM, optimum temperature and pH 80°C and 8 respectively. No detectable enzyme activity found when L-Glutamine was used as the substrate. In silico studies have shown that the enzyme exists as a homodimer having Arg11, Ala87, Thr110, His112, Gln142, Leu172, and Lys232 being the putative active site residues. The free energy change calculated by molecular docking studies of enzyme and substrate was found as ∆G ­ 4.5 kJ/mole indicating the affinity of enzyme with the substrate. IC50 values of 5U/mL to 7.5U/mL were determined for FB, caco2 cells and HepG2 cells. A calculated amount of enzyme (5U/mL) exhibited 78% to 55% growth inhibition of caco2 and HepG2 cells. In conclusion, the recombinant enzyme produced and characterized in the present study offers a good candidate for the treatment of cancer. The procedures adopted in the present study can be prolonged for in vivo studies.

A L-asparaginase, que catalisa a degradação da L-asparagina em L-aspartato e amônia, é uma enzima de importância terapêutica no tratamento do câncer, especialmente dos linfomas e da leucemia. O presente estudo descreve a produção recombinante, propriedades e potencial anticancerígeno da enzima de Pyrococcus abyssi, um archaeon hipertermofílico. Existem dois genes que codificam para a asparaginase no genoma desse organismo. Um gene de 918 bp, que codifica 305 aminoácidos, foi amplificado por PCR e clonado na cepa BL21 (DE3) de E. coli usando o plasmídeo pET28a (+). A produção da enzima recombinante foi induzida sob 0,5mM de IPTG, purificada por desnaturação seletiva por calor e cromatografia de troca iônica. A enzima purificada foi analisada quanto à cinética, estrutura in silico e propriedades anticancerígenas. A enzima recombinante apresentou peso molecular de 33 kDa, atividade específica de 1.175 U / mg, valor de KM 2,05 mM, temperatura ótima de 80º C e pH 8. Nenhuma atividade enzimática detectável foi encontrada quando a L-glutamina foi usada como substrato. Estudos in silico mostraram que a enzima existe como um homodímero, com Arg11, Ala87, Thr110, His112, Gln142, Leu172 e Lys232 sendo os resíduos do local ativo putativo. A mudança de energia livre calculada por estudos de docking molecular da enzima e do substrato foi encontrada como ∆G ­ 4,5 kJ / mol, indicando a afinidade da enzima com o substrato. Valores de IC50 de 5U / mL a 7,5U / mL foram determinados para células FB, células caco2 e células HepG2. Uma quantidade de enzima (5U / mL) apresentou inibição de crescimento de 78% a 55% das células caco2 e HepG2, respectivamente. Em conclusão, a enzima recombinante produzida e caracterizada no presente estudo é uma boa possibilidade para o tratamento do câncer. Os procedimentos adotados na presente pesquisa podem ser aplicados para estudos in vivo.

L-Asparaginase e perspectivas no tratamento da leucemia linfoblástica aguda: revisão de literatura / L-Asparaginase and perspectives in the treatment of leukemia acute lymphoblastic: literature review

Introdução: A L-asparaginase tem sido estudada como alternativa no tratamento da Leucemia Linfoblástica Aguda (LLA) uma vez que possui a capacidade de induzir apoptose em células leucêmicas sem causar danos às células normais. Estudos mostraram benefícios no tratamento da LLA, porém com o risco de desenvolver efeitos adversos. Objetivo: Este trabalho visa apresentar e explicar o histórico da L-asparaginase, desafios enfrentados pelo Brasil, mecanismos de ação que envolvem as formas da enzima e efeitos adversos de sua utilização. Métodos: Foram incluídos neste trabalho 54 artigos na língua portuguesa e inglesa consultados em bancos de artigos como PubMed e SciELO, entre o período de 1953 até 2021. Resultados: A L-asparaginase é uma enzima que converte asparagina em aspartato e amônia, isolada a partir de colônias de Escherichia coli e de Erwinia chrysanthemi, além disso foi polimerizada com polietilenoglicol. O uso de corticosteroides, anti-histamínicos e suplementação vitamínica se mostraram eficientes para amenizar os efeitos adversos. Conclusões: É necessário evitar um desabastecimento de L-Asparaginase no Brasil, principalmente por conta da dificuldade de comercialização e alto custo, mesmo sendo um medicamento presente na lista da Organização Mundial da Saúde, considerado essencial.

Introduction: L-asparaginase has been studied as an alternative in the treatment of Acute Lymphoblastic Leukemia (ALL) since it has the ability to induce apoptosis in leukemic cells without causing damage to normal cells. Studies have shown benefits in the treatment of ALL, but with the risk of developing adverse effects. Objective: This work aims to present and explain the history of L-asparaginase, challenges faced by Brazil, mechanisms of action involving the forms of the enzyme and adverse effects of its use. Methods: 54 articles in Portuguese and English were included in this work, consulted in article banks such as PubMed and SciELO, between the period of 1953 to 2021. Results: L-asparaginase is an enzyme that converts asparagine into aspartate and ammonia, isolated from from Escherichia coli and Erwinia chrysanthemi colonies, it was also polymerized with polyethylene glycol. The use of corticosteroids, antihistamines and vitamin supplementation proved to be efficient in mitigating adverse effects. Conclusions: It is necessary to avoid a shortage of L-Asparaginase in Brazil, mainly due to the difficulty of commercialization and high cost, even though it is a drug present on the World Health Organization list, considered essential.

Desenvolvimento e caracterização de lipossomas peguilados para veiculação de L-asparaginase / Development and characterization of peg-grafted liposomes for lasparaginase encapsulation

A Leucemia Linfoide Aguda (LLA) é um câncer de maior incidência em crianças, e tem a Lasparaginase (ASNase) como fármaco amplamente utilizado no tratamento dos afetados. A ASNase catalisa a hidrólise do aminoácido L-asparagina (Asn), presente na corrente sanguínea, a ausência do aminoácido no meio extracelular leva à morte células leucêmicas, que necessitam deste aminoácido para as funções celulares. Fatores envolvendo a eficiência do tratamento com ASNase como reações adversas e curta meia-vida, principalmente devido ao reconhecimento pelo sistema imune e degradação por proteases, limitam a sua eficácia. A encapsulação da enzima em lipossomas pode conferir proteção à degradação, melhorar seu perfil farmacocinético e diminuir os efeitos adversos, de forma a melhorar o tratamento da LLA sendo este o objetivo desse trabalho. Lipossomas de DOPC (1,2-dioleoil-sn-glicero-3-fosfocolina) e DMPC (1,2-dimiristoil-snglicero-3-fosfocolina) foram desenvolvidos empregando-se o método de hidratação do filme lipídico e diferentes protocolos de preparo contendo ou não diferentes concentrações de 18:0 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polietilenogicol)-2000] (DSPE-PEG). Os lipossomas produzidos foram utilizados para encapsular a ASNase e os sistemas contendo ou não ASNase encapsulada foram caracterizados por espalhamento de luz dinâmico (DLS), potencial zeta, microscopia eletrônica de transmissão (MET) e criomicroscopia de transmissão. Adicionalmente, foram avaliados a taxa de encapsulação e o perfil de permeabilidade das vesículas à L-asparagina. As análises de DLS mostraram que as nanoestruturas formadas empregando-se agitação magnética a partir de sistemas contendo 10% e 20% de DSPE-PEG possuem diâmetro hidrodinâmico menor (~ 25 nm a 60 nm) que os mesmos sistemas sem o fosfolipídio peguilado (~190 nm a 222 nm), demonstrando a relação entre a diminuição do tamanho e o aumento da quantidade de fosfolipídio peguilado e possível formação de estruturas micelares ou bicelares. O emprego de agitação em vórtex para hidratação do filme lipídico, adição do antioxidante -tocoferol e redução da concentração de DSPE-PEG (5% e 10%) levou à formação de sistemas com diâmetro hidrodinâmico maior, sendo esse protocolo e concentrações de PEG definidos como padrão. As análises de MET comprovaram a formação de lipossomas com diâmetro hidrodinâmico semelhante ao observado por DLS; com a utilização da criomicroscopia foi possível observar os lipossomas sem deformações. Os lipossomas de DMPC/DSPE-PEG 10% apresentaram maior permeabilidade à L-asparagina ao longo do tempo e, portanto, poderiam funcionar como nanoreatores, depletando o aminoácido da circulação. Estudos in vitro com células tumorais devem ser realizados e em seguida estudos in vivo, para confirmar este potencial

L-asparaginase (ASNase) is a first-choice drug, combined with other drugs, in therapeutic schemes to treat Acute Lymphoblastic Leukemia (ALL) in children and adolescents. ASNase catalyzes the hydrolysis of L-asparagine (Asn) in the bloodstream; since ALL cells cannot synthesize this amino acid, protein synthesis is impaired leading to leukemic cells death by apoptosis. In spite of its therapeutic importance, treatment with ASNase is associated to side effects, mainly hypersensitivity and immunogenicity. Another drawback refers to degradation by plasma proteases that altogether with immunogenicity shortens the enzyme half-life. Encapsulation of ASNase in liposomes, vesicular nanostructures formed by the self-aggregation of phospholipids, is an attractive alternative that possibly will protect the enzyme from plasma proteases, resulting on better pharmacokinetics profile. In this work, we prepared by thin film hydration liposomal formulations of the phospholipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or 1,2-dimyristoyl-sn-glycero-3- phosphocholine (DMPC) containing or not different concentrations of 18:0 1,2-distearoyl-snglycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG), and encapsulated ASNase by electroporation. The systems containing or not ASNase were analyzed by Dynamic Light Scattering, zeta potential and Electron Microscopy. The encapsulation efficiency and vesicles permeability were also evaluated. According to the DLS analysis, the nanostructures formed by film hydration under magnetic stirring employing 10% or 20% DSPE-PEG presented smaller hydrodynamic diameter (~ 25 nm to 60 nm) than the same systems without the pegylated phospholipid (~ 190 nm to 222 nm), demonstrating the relation between size and the amount of pegylated phospholipid that results in formation of micellar or bicellar structures. The protocol was stabilize by hydration of the lipid film under vortex agitation, addition of the antioxidant - tocopherol and reduction of the concentration of DSPE-PEG (5% and 10%), what altogether led to the formation of nanostructures of higher hydrodynamic diameter and monodisperse systems. TEM analyzes confirmed the formation of liposomes with hydrodynamic diameter similar to that observed by DLS; with the use of cryomicroscopy it was possible to observe the liposomes without deformations. Liposomes of DMPC/DSPE-PEG 10% showed permeability to L-asparagine over time and, therefore, could function as nanoreactors, depleting the circulating amino acid

Two-Step Purification of L-Asparaginase from Acrylaway® L

Abstract L-Asparaginase (L-ASNase) is a biopharmaceutical used for acute lymphoblastic leukaemia (ALL) treatment, dramatically increasing the patients' chance of cure. However, its production and distribution in developing countries were disrupted because of its low profitability, which caused great concern among patients. This study evaluates the feasibility of combining fractional precipitation and aqueous two-phase systems (ATPS) to purify L-ASNase from a low-grade product, commercially known as Acrylaway® L. The ATPS purification results were not particularly expressive compared to the two-step purification process composed of ethanol precipitation and gel filtration, which was able to recover the target molecule with a purification factor over 5 fold. Thus, we studied a purification process capable of manufacturing pharmaceutical grade L-ASNase from a commercially available low-grade raw material; however, improvements regarding its throughput must be achieved, and high purity is the first step to apply it as a new biopharmaceutical product. The proposed process could pose as a short-time solution to mitigate its shortage while a cost-effective production plant is being developed.

Studies on the recombinant production and anticancer activity of thermostable L- asparaginase I from Pyrococcus abyssi / Estudos sobre a produção recombinante e atividade anticancerígena da L asparaginase I termoestável de Pyrococcus abyssi

L-Asparaginase catalysing the breakdown of L-Asparagine to L-Aspartate and ammonia is an enzyme of therapeutic importance in the treatment of cancer, especially the lymphomas and leukaemia. The present study describes the recombinant production, properties and anticancer potential of enzyme from a hyperthermophilic archaeon Pyrococcus abyssi. There are two genes coding for asparaginase in the genome of this organism. A 918 bp gene encoding 305 amino acids was PCR amplified and cloned in BL21 (DE3) strain of E. coli using pET28a (+) plasmid. The production of recombinant enzyme was induced under 0.5mM IPTG, purified by selective heat denaturation and ion exchange chromatography. Purified enzyme was analyzed for kinetics, in silico structure and anticancer properties. The recombinant enzyme has shown a molecular weight of 33 kDa, specific activity of 1175 U/mg, KM value 2.05mM, optimum temperature and pH 80°C and 8 respectively. No detectable enzyme activity found when L-Glutamine was used as the substrate. In silico studies have shown that the enzyme exists as a homodimer having Arg11, Ala87, Thr110, His112, Gln142, Leu172, and Lys232 being the putative active site residues. The free energy change calculated by molecular docking studies of enzyme and substrate was found as ∆G – 4.5 kJ/mole indicating the affinity of enzyme with the substrate. IC50 values of 5U/mL to 7.5U/mL were determined for FB, caco2 cells and HepG2 cells. A calculated amount of enzyme (5U/mL) exhibited 78% to 55% growth inhibition of caco2 and HepG2 cells. In conclusion, the recombinant enzyme produced and characterized in the present study offers a good candidate for the treatment of cancer. The procedures adopted in the present study can be prolonged for in vivo studies.

A L-asparaginase, que catalisa a degradação da L-asparagina em L-aspartato e amônia, é uma enzima de importância terapêutica no tratamento do câncer, especialmente dos linfomas e da leucemia. O presente estudo descreve a produção recombinante, propriedades e potencial anticancerígeno da enzima de Pyrococcus abyssi, um archaeon hipertermofílico. Existem dois genes que codificam para a asparaginase no genoma desse organismo. Um gene de 918 bp, que codifica 305 aminoácidos, foi amplificado por PCR e clonado na cepa BL21 (DE3) de E. coli usando o plasmídeo pET28a (+). A produção da enzima recombinante foi induzida sob 0,5mM de IPTG, purificada por desnaturação seletiva por calor e cromatografia de troca iônica. A enzima purificada foi analisada quanto à cinética, estrutura in silico e propriedades anticancerígenas. A enzima recombinante apresentou peso molecular de 33 kDa, atividade específica de 1.175 U / mg, valor de KM 2,05 mM, temperatura ótima de 80º C e pH 8. Nenhuma atividade enzimática detectável foi encontrada quando a L-glutamina foi usada como substrato. Estudos in silico mostraram que a enzima existe como um homodímero, com Arg11, Ala87, Thr110, His112, Gln142, Leu172 e Lys232 sendo os resíduos do local ativo putativo. A mudança de energia livre calculada por estudos de docking molecular da enzima e do substrato foi encontrada como ∆G – 4,5 kJ / mol, indicando a afinidade da enzima com o substrato. Valores de IC50 de 5U / mL a 7,5U / mL foram determinados para células FB, células caco2 e células HepG2. Uma quantidade de enzima (5U / mL) apresentou inibição de crescimento de 78% a 55% das células caco2 e HepG2, respectivamente. Em conclusão, a enzima recombinante produzida e caracterizada no presente estudo é uma boa possibilidade para o tratamento do câncer. Os procedimentos adotados na presente pesquisa podem ser aplicados para estudos in vivo.

Studies on the recombinant production and anticancer activity of thermostable L- asparaginase I from Pyrococcus abyssi

Abstract L-Asparaginase catalysing the breakdown of L-Asparagine to L-Aspartate and ammonia is an enzyme of therapeutic importance in the treatment of cancer, especially the lymphomas and leukaemia. The present study describes the recombinant production, properties and anticancer potential of enzyme from a hyperthermophilic archaeon Pyrococcus abyssi. There are two genes coding for asparaginase in the genome of this organism. A 918 bp gene encoding 305 amino acids was PCR amplified and cloned in BL21 (DE3) strain of E. coli using pET28a (+) plasmid. The production of recombinant enzyme was induced under 0.5mM IPTG, purified by selective heat denaturation and ion exchange chromatography. Purified enzyme was analyzed for kinetics, in silico structure and anticancer properties. The recombinant enzyme has shown a molecular weight of 33 kDa, specific activity of 1175 U/mg, KM value 2.05mM, optimum temperature and pH 80°C and 8 respectively. No detectable enzyme activity found when L-Glutamine was used as the substrate. In silico studies have shown that the enzyme exists as a homodimer having Arg11, Ala87, Thr110, His112, Gln142, Leu172, and Lys232 being the putative active site residues. The free energy change calculated by molecular docking studies of enzyme and substrate was found as G 4.5 kJ/mole indicating the affinity of enzyme with the substrate. IC50 values of 5U/mL to 7.5U/mL were determined for FB, caco2 cells and HepG2 cells. A calculated amount of enzyme (5U/mL) exhibited 78% to 55% growth inhibition of caco2 and HepG2 cells. In conclusion, the recombinant enzyme produced and characterized in the present study offers a good candidate for the treatment of cancer. The procedures adopted in the present study can be prolonged for in vivo studies.

Resumo A L-asparaginase, que catalisa a degradação da L-asparagina em L-aspartato e amônia, é uma enzima de importância terapêutica no tratamento do câncer, especialmente dos linfomas e da leucemia. O presente estudo descreve a produção recombinante, propriedades e potencial anticancerígeno da enzima de Pyrococcus abyssi, um archaeon hipertermofílico. Existem dois genes que codificam para a asparaginase no genoma desse organismo. Um gene de 918 bp, que codifica 305 aminoácidos, foi amplificado por PCR e clonado na cepa BL21 (DE3) de E. coli usando o plasmídeo pET28a (+). A produção da enzima recombinante foi induzida sob 0,5mM de IPTG, purificada por desnaturação seletiva por calor e cromatografia de troca iônica. A enzima purificada foi analisada quanto à cinética, estrutura in silico e propriedades anticancerígenas. A enzima recombinante apresentou peso molecular de 33 kDa, atividade específica de 1.175 U / mg, valor de KM 2,05 mM, temperatura ótima de 80º C e pH 8. Nenhuma atividade enzimática detectável foi encontrada quando a L-glutamina foi usada como substrato. Estudos in silico mostraram que a enzima existe como um homodímero, com Arg11, Ala87, Thr110, His112, Gln142, Leu172 e Lys232 sendo os resíduos do local ativo putativo. A mudança de energia livre calculada por estudos de docking molecular da enzima e do substrato foi encontrada como G 4,5 kJ / mol, indicando a afinidade da enzima com o substrato. Valores de IC50 de 5U / mL a 7,5U / mL foram determinados para células FB, células caco2 e células HepG2. Uma quantidade de enzima (5U / mL) apresentou inibição de crescimento de 78% a 55% das células caco2 e HepG2, respectivamente. Em conclusão, a enzima recombinante produzida e caracterizada no presente estudo é uma boa possibilidade para o tratamento do câncer. Os procedimentos adotados na presente pesquisa podem ser aplicados para estudos in vivo.

Analysis and identification of a case of pegaspargase-induced acute pancreatitis and literature review / 中国药房

OBJE CTIVE To investigate the clinical characteristics of a dverse drug reactions of asparaginase-associated pancreatitis（AAP），so as to provide reference for clinical safe medication. METHODS Analysis and identification were performed on a severe adverse reaction case of acute pancreatitis complicated with diabetic ketoacidosis and liver injury in a patient with acute lymphoblastic leukemia in our hospital after using pegaspargase. Retrieved from Wanfang database ，CNKI，PubMed and Embase database，case reports of AAP were collected and summarized in terms of patient demographics ，drug use ，incubation period and adverse reaction outcome. Combined with this case ，the disease characteristics and potential risk factors of AAP were analyzed and discussed. RESULTS After analysis and identification ，it was determined that AAP occurred in this patient. A total of 47 case reports were retrieved from the database ，and a total of 52 patients（including this patient ）were included in the analysis ，including 29 males and 23 females，mainly minors （65.4％）. L-asparaginase was the main asparaginase preparation that causes AAP （80.8％）. Gastrointestinal symptoms were the main prodromal symptoms （92.3％），which could be accompanied by other asparaginase related adverse reactions. AAP could occur after 1-33 times of administration ，and the median latency was 14 days after administration；compared with children ，median latency of AAP in adult patients was shortened significantly （11 d vs. 16 d，P＝ 0.049）；the median latency of AAP had longer tendency in patients treated with pegaspargase than that of L-asparaginase （17 d vs. 12.5 d，P＝0.490）. Of the cases included in the analysis ，8 patients died due to AAP ，1 of which was related to re-exposure to asparaginase preparations. CONCLUSIONS Acute pancreatitis is a serious and potentially fatal adverse drug reaction of ； asparaginase preparations. Clinical medical staff should pay attention to the characteristics of AAP ，consider the possibility ： of AAP when the patients have gastrointestinal symptoms and do a good job in patient education and pharmaceutical care to minimize the damage caused by AAP to patients.

Pancreatitis aguda en niños con enfermedades hematooncológicas: aspectos clínicos y tratamiento / Acute pancreatitis in children with hemato-oncological diseases: clinical aspects and treatment

Resumen La pancreatitis aguda es una enfermedad inflamatoria del páncreas. Se observa con mayor frecuencia en niños bajo tratamiento por alguna enfermedad hematooncológica y se asocia principalmente con la administración de L-asparaginasa. Identificar esta complicación de forma temprana y establecer un plan terapéutico adecuado puede mejorar el pronóstico y reducir el riesgo de otras complicaciones. En este trabajo se realizó una revisión crítica de la literatura actual, con especial énfasis en los aspectos clínicos, el diagnóstico y el tratamiento de la pancreatitis aguda en niños con cáncer.

Abstract Acute pancreatitis is an inflammatory disease of the pancreas. It is currently seen more frequently in children undergoing treatment for a hemato-oncological disease and it is mainly associated with the administration of L-asparaginase. The early identification of this complication and the establishment of an appropriate therapeutic plan can improve its prognosis and reduce the risk of other complications. In this article, we make a critical review of the current literature, with special emphasis on the clinical aspects, diagnosis, and treatment of acute pancreatitis in children with cancer.

Allergic reactions to asparaginase: retrospective cohort study in pediatric patients with acute lymphoid leukemia

ABSTRACT Introduction: To assess the frequency of allergic reactions to asparaginase (ASP) and possible risk factors for reactions in a cohort of pediatric patients. Method: The study was performed based on retrospective data from patients under acute lymphoid leukemia treatment in a general university hospital located in southern Brazil. Information on patients who used ASP from 2010 to 2017 was collected. Allergic reactions were identified in electronic medical records. Results: Among the 98 patients included in the study, 16 (16.3 %) experienced an allergic reaction to native l-asparaginase (L-ASP). Of the 22 patients (22.4 %) that received only intravenous (IV) administration of l-ASP, 10 (62.5 %) had allergic reactions, while 48 patients (49 %) received intramuscular (IM) administration and 28 (28.6 %) received IV and IM administrations. The occurrence of allergic reactions differed between the groups (p < 0.001), and IV administration was associated with allergic reactions. Association was also observed between the severity of the reaction and the route of administration, with the IM route associated with grade 2 and IV route associated with grade 3. Occurrence of allergic reactions was higher when the commercial formulation of l-ASP, Leuginase®, was used (p = 0.0009 in the analysis per patient and p = 0.0003 in the analysis per administration). Conclusions: The IV administration and commercial Leuginase® presentation were associated with more allergic reactions in the study population, which corroborates the findings in the literature. The IV route was also associated with higher severity of reactions in the present study.

Análise Técnico-Econômica para a produção de biofármacos de L-asparaginase / Technical-Economic analysis for the production of L-asparaginase biopharmaceuticals

A enzima L-asparaginase é comumente utilizada como biofármaco para o tratamento da Leucemia Linfoblástica Aguda e possui altas taxas de cura com o medicamento disponível no mercado. Atualmente a aquisição deste biofármaco é fruto integral de importação, não sendo realizada produção nacional, muito embora existam grupos de pesquisas nacionais que trabalham em pesquisas e no desenvolvimento de biofármacos alternativos da L-asparaginase. Assim, a presente dissertação tem como objetivo realizar análises técnico-econômicas para avaliar a viabilidade de implementação industrial de bioprocessos para a produção da L-asparaginase do tipo Erwinase PEGuilada e não PEGuilada, que foram previamente desenvolvidos na FCF-USP. As análises técnico-econômicas foram conduzidas por meio do software SuperPro Design® (Intelligen, Inc.) e permitiram adaptar o processo laboratorial para um processo piloto e possibilitaram estimar os valores de custo de produção unitário (Unity Cost of Production - UPC) de US$ 12,37/mg e US$ 3,46/mg para a L-asparaginase monoPEGuilada e nativa obtida por processo similar, respectivamente. O custo unitário de produção para a enzima peguilada foi, portanto, estimado em cerca de 4 vezes o mesmo custo para a produção da enzima peguilada, sendo tal aumento de custo devido às operações de peguilação, já que ambas as plantas foram mantidas nas mesmas dimensões. Ainda, foram obtidos indicadores econômicos, que indicam a atratividade do processo desenvolvido, muito embora tenham sido identificados diversos gargalos de processo e fatores a serem otimizados e melhorados de forma a tornar o processo mais atrativo sob os pontos de vista técnico e econômico. Em uma análise de sensibilidade preliminar um aumento factível da densidade celular já mostra que é possível reduzir em mais de 30% o UPC. De toda forma, ainda que não otimizado, o processo apresentou valores e dados compatíveis com os biofármacos de L-asparaginase já disponíveis no mercado

The enzyme L-asparaginase is commonly used as a biopharmaceutical in the treatment of Acute Lymphoblastic Leukemia, presenting high cure rates with the formulations available on the market. Nowadays, the acquisition of this biopharmaceutical is only from importation, given that there is no national production being carried out, although there are national research groups working on research and development of alternative L-asparaginase biopharmaceuticals. Thus, this project aims at carrying out technical-economic analyzes to evaluate the viability of industrial implementation of bioprocesses for the production of L-asparaginase of the PEGylated and non-PEGylated Erwinase type previously developed at FCF-USP. The technical-economic analyzes, conducted by means of the software SuperPro Design® (Intelligen, Inc.), allowed to adapt the laboratory process to a pilot process and made it possible to estimate the unit cost of production (UPC) values of US $ 12.37 / mg and US $ 3.56 / mg for monoPEGylated L-asparaginase and bare obtained by similar process, respectively. The unit cost of production for the pegylated enzyme was, therefore, estimated at about 4 times the same cost for the production of the pegylated enzyme, such an increase in cost due to pegylation operations, since both plants were maintained in the same dimensions. Moreover, economic indicators were obtained, which indicate the attractiveness of the developed process. However, several process bottlenecks and factors to be optimized and improved were identified to make the process more attractive from the technical and economic point of view. In a preliminary sensitivity analysis, a feasible increase in cell density already shows that it is possible to reduce UPC by more than 30%. Accordingly, although not optimized, the process presented values and data compatible with the L-asparaginase biopharmaceuticals already available on the market

Estudo da estabilidade e peguilação de L-asparaginase em soluções aquosas de líquidos iônicos de imidazólio / Study of the stability and pegylation of L-asparaginase in aqueous imidazole ionic liquid solutions

A enzima L-asparaginase de Escherichia coli (ASNase) é um biofármaco indicado para o tratamento de leucemia linfoblástica aguda, mas que pode causar reações de hipersensibilidade nos pacientes tratados. Na tentativa de amenizar esse efeito, foi desenvolvida a PEG-ASNase (enzima conjugada com polietilenoglicol) que apresenta a vantagem de ser menos imunogênica e ter maior meia-vida biológica. Mais recentemente, novas abordagens têm sido desenvolvidas visando aprimorar os processos de PEGuilação por meio de reações sítio dirigidas, por exemplo N-terminal, a fim de promover maior similaridade lote a lote e controle das características farmacocinéticas e farmacodinâmicas do biofármaco. Porém, existe ainda uma limitação associada à hidrólise do PEG reativo, desta forma surge a necessidade de procurar solventes alternativos para a PEGuilação que permitam manter a estabilidade das proteínas, aumentar o rendimento de PEGuilação e a estabilidade do PEG reativo. Nesse trabalho, líquidos iônicos foram investigados como solventes alternativos para a peguilação N-terminal de PEG-ASNase. Para tal, a estabilidade de ASNase em Lis foi investigada em LIs da família metil-imidazol, analisando a influência do aumento da cadeia alquílica e de diferentes ânions. A estabilidade da ASNase é favorecida quando em contato com Lis relativamente hidrofóbicos ([C2mim]Cl, [C4mim]Cl e [C6mim]Cl), mas sua a atividade é prejudicada quando o LI é muito polar, como o [C4mim][(CH3)2PO4] ou anfifílico como o [C12mim]Cl. Apesar de seu efeito desnaturante, o [C4mim][(CH3)2PO4] resultou no maior rendimento da reação de PEGuilação da ASNase (56%) quando empregado a 75% e a reação realizada em 10 min. O [C4mim]Cl resultou em rendimento semelhante ao tampão fosfato (~ 49%), mas ambos os LIs reduziram a poliPEGuilação. Portanto, os Lis [C4mim]Cl e [C4mim][(CH3)2PO4] fornecem uma alternativa viável à reação de PEGuilação pela redução na formação de espécies poliPEGuiladas, o que facilitaria os processos de purificação e permitiria maior controle lote a lote da reação, bem como pelo aumento do rendimento da reação no caso do [C4mim][(CH3)2PO4]

Escherichia coli L-asparaginase enzyme (ASNase) is a biopharmaceutical indicated for the treatment of acute lymphoblastic leukemia, but may cause hypersensitivity in the patients used. In an attempt to alleviate this effect, PEG-ASNase (polyethylene glycol conjugated enzyme) was developed, which has the advantage of being less immunogenic and having a longer biological half-life. More recently, new approaches have been applied to improve PEGylation processes through targeted sites, for example N-terminal, in order to promote greater similarity to the batch and control of the pharmacokinetic and pharmacodynamic characteristics of the biopharmaceutical. However, there is still a limitation associated with reactive PEG hydrolysis, thus increasing the need to look for alternative PEGylation solvents to maintain protein stability, increase PEGylation yield and use reactive PEG. In this work, ions were investigated as alternative solvents for the N-terminal PEG-ASNase. For example, a stability of ASNase in ILs was investigated in imidazole ILs by analyzing the influence of increased alkyl chain and different anions. ASNase stability is enhanced when in contact with relatively hydrophobic ILs ([C2min]Cl, [C4min]Cl and [C6min]Cl), but its activity is impaired when very polar ILs such as [C4min][(CH3)2PO4] or amphiphilic as [C12mim]Cl. Despite its denaturing effect, [C4min][(CH3)2PO4] resulted in higher yield of ASNase PEGylation reaction (56%) when employed at 75% and reaction performed in 10 min. [C4min]Cl yielded similar phosphate buffer yield (~ 49%), but both ILs reduced polyPEGylation. Therefore, [C4min]Cl and [C4min][(CH3)2PO4] Ils may use a viable alternative to the PEGylation reaction and reduce the formation of polyPEGylated species, or that facilitate purification processes and allow for greater batch use of the solution, as well as increased reaction yield in the case of [C4min][(CH3)2PO4]

Cetoacidose diabética e pancreatite secundárias à peg-asparaginase / Diabetic ketoacidosis and pancreatitis secondary to peg-asparaginase

RESUMO: Objetivos: Apresentar um caso raro de cetoacidose diabética (CAD) e pancreatite secundários ao uso de PEG-asparaginase em paciente pediátrico em tratamento para leucemia linfoblástica aguda (LLA) e alertar quanto aos sinais que remetem a esses diagnósticos. Descrição do caso: Adolescente do sexo feminino, 10 anos e 11 meses, em tratamento para LLA e uso prévio de PEG-asparaginase há seis dias da internação, admitida com choque hipotensivo grave e encaminhada à Unidade de Terapia Intensiva. Inicialmente o quadro foi interpretado como choque séptico. Em seguida a anamnese detalhada e os exames laboratoriais direcionaram para os diagnósticos de CAD e pancreatite, iniciando-se as intervenções específicas. Recebe alta hospitalar após 30 dias, sem necessidade de insulinoterapia, mas com reposição de enzimas pancreáticas. Comentários: Geralmente, às crianças com LLA gravemente enfermos e leucopênicos, atribui-se apenas o diagnóstico de sepse, que é um diagnóstico prioritário. Entretanto, no grupo em uso de PEG-asparaginase, o pediatra emergencista deve estar alerta ao raciocínio diferencial envolvendo CAD e pancreatite, o que pode ser bem difícil inicialmente. O alerta dos diagnósticos diferenciais do choque séptico, mesmo que raros, na assistência a pacientes oncológicos pediátricos, além da correta e pronta identificação do quadro e seu manejo apropriado, correlacionam-se diretamente ao sucesso terapêutico e, em algumas situações, à sobrevivência do paciente. (AU)

ABSTRACT: Objectives: We present a rare case of diabetic ketoacidosis (DKA) and pancreatitis secondary to the use of PEG-asparaginase in a pediatric patient being treated for acute lymphoblastic leukemia (ALL) and draw attention to the signs that refer to these diagnoses. Case description: A female adolescent, aged 10 years and 11 months, undergoing treatment for ALL, used PEG-asparaginase for 6 days prior to admission. She was hospitalized due to severe hypotensive shock and was then referred to the intensive care unit. Initially, the clinical condition was interpreted as septic shock. However, detailed anamnesis and results of laboratory tests led to the diagnoses of DKA and pancreatitis; hence, appropriate interventions were initiated. She was discharged after 30 days without the need for insulin therapy but received pancreatic enzyme replacement therapy. Comments: Generally, diagnosing severely ill and leukopenic children with ALL is only attributed to sepsis, which is a priority diagnosis. However, in the group treated with PEG-asparaginase, the pediatric emergency specialist should consider differential reasoning in patients with DKA and pancreatitis, which can be quite difficult to assess initially. Alertness towards the differential diagnoses of septic shock, although rare, in the care of pediatric oncology patients, in addition to the correct and prompt identification of the condition and provision of appropriate management, directly correlates with treatment success and, in some situations, the improvement in patient's survival. (AU)

Case report of silent inactivation of Asparaginase in acute lymphoblastic leukemia with late bone marrow relapse / 中华实用儿科临床杂志

Retrospective analysis was performed on 1 child with silent inactivation (SI) of asparaginase (ASNas) who was diagnosed with acute lymphoblastic leukemia (ALL) and treated in the First Affiliated Hospital, Sun Yat-Sen University in October 2019.The patient was a 9 years and 3 months old boy who was diagnosed as ALL accompanied with late bone marrow relapse.After pegylated Escherichia coli-Asparaginase (PEG-ASNase) was given, he did not have the expected treatment-related adverse reactions, including hyperammonemia, hypofibrinogenemia, and the low activation of antithrombin Ⅲ (ATⅢ). The plasma asparagine (ASN) concentration failed to meet the depletion criteria and the ASNase activity was 64.5 U/L.Therefore, the SI of ASNase was confirmed.Erwinase was used to replace PEG-ASNase, the lowest level of ATⅢ was 33%, and the lowest level of fibrinogen was 1.20 g/L.Hyperammonemia and decreased ASN were also observed, and the ASNase activity was 1 813.0 U/L.All the above suggested that when, SI occurred, the replacement by Erwinase was effective.The ASNase activity should be monitored in ALL patients who were treated with ASNase.Monitoring the treatment-related adverse reactions such as hyperammonia and coagulation disorders closely has important implications to the SI of ASNase when the detection of ASNase activity was unavailable.

Clinical characteristics of children with acute lymphoblastic leukemia presenting with secondary acute pancreatitis / 中国肿瘤临床

Objective: To analyze the clinical characteristics of children with acute lymphoblastic leukemia (ALL) diagnosed with secondary acute pancreatitis(AP). Methods: We collected data from a total of 11 patients with ALL and secondary acute pancreatitis who were treated in Tianjin Children's Hospital from February 2013 to February 2020. All patients followed the China Children's Leukemia Collaborative Group-Acute Lymphocytic Leukemia-2008 (CCLG- ALL 2008) combined regimen. We summarized the patient's risk stratification, primary clinical manifestations, treatment stage, cause of pancreatitis, and cumulative dosage of polyethylene glycol conjugated asparaginase (PEG-ASP). The results from examinations such as pancreatic enzyme index, imaging, blood routine, liver and kidney function, blood lipid and blood glucose, and coagulation function were also compared. Finally, the therapeutic effects and outcomes of the patients were compared; and subsequently their clinical characteristics were analyzed. Results: Among the 11 patients 7 were male, and 4 were female; aged between 1-14 years old, with a median age of 6 years. Ten patients had type B acute lymphoblastic leukemia (B-ALL) and 1 had type T acute lymphoblastic leukemia (T-ALL). Pancreatitis was observed in 8 cases within 45 days after start of therapy, in one high-risk case after the second cycle of HR3' chemotherapy and in 2 cases after intensive chemotherapy. It was observed in 10 cases after PEG-ASP treatment, and in one T-ALL case concomitant with tumor lysis syndrome following cyclophosphamide-dexamethasone cytoduction treatment. It manifested primarily as abdominal pain, nausea and vomiting in 11 patients; 8 patients had hypocalcemia; 9 patients had low albumin levels; and 8 patients had abnormal coagulation function. No hypersensitivity was observed. Conclusions: Secondary AP occurs in children with ALL during the early stages of combined chemotherapy. Most of the complications are related to the asparaginase treatment. The severity of the disease is not significantly correlated with the risk stratification of the disease and the cumulative dose of asparaginase. Serum pancreatic enzyme (PE) testing and imaging tests can help assess the clinical status and guide the later prognosis and medication.

Mining and Evaluation of Post-marketing Safe Alert Signals of Pegaspargase and L-asparaginase Based on BCPNN Method / 中国药房

OBJECTIVE： To mine and evaluate the post-marketing safety alert signals of pegaspargase （PEG-ASP） and L-asparaginase （L-ASP），and compare the safety differences between them ，so as to provide reference for clinical safe and rational drug use. METHODS ： The adverse drug event （ADE） reports of PEG-ASP and L-ASP issued by FDA adverse event reporting system from Jan. 1st，2004-Jun. 30th，2020 were retrieved. BCPNN method was used to mine the safety signals of these two drugs under the condition that the lower limit of information component （IC－2SD）＞0 and the number of events ≥3. The medium and strong signals of two drugs with IC －2SD≥1.5 were evaluated and compared in 8 system organ class，such as gastrointestinal system ，hepatobiliary system ，blood and lymphatic system ，blood vessels and lymphatic vessels ， nervous system ，immune system ，metabolism and nutrition ，various examinations. IC value of specific ADE signal and its 95％ confidence interval were analyzed by time scanning spectrum. RESULTS & CONCLUSIONS ：The reports of PEG-ASP and L-ASP as suspected drugs were 2 324 and 3 824；67 and 68 medium and strong signals were included ，respectively. In gastrointestinal system，the common strong signal of PEG-ASP and L-ASP was necrotic pancreatitis. In hepatobiliary system ，both of them showed strong signal in venoocclusive liver disease ，and this ADE was not included in the drug instruction. In blood and lymphatic system ， common strong signals of the two drugs were febrile neutropenia ，coagulation disorder ，neutropenia and febrile bone marrow regeneration disorder ；in blood vessels and lymphatic vessels ，in addition to haemodynamic instability ，IC values of other signals of L-ASP were higher than those of PEG-ASP. In nervous system ，IC values of other signals of L-ASP were higher than those of PEG-ASP except for intracranial haemorrhage. In immune system ，anaphylactic reaction was a medium signal for L-ASP but was a strong signal for PEG-ASP. In metabolism and nutritional diseases ，except for tumor lysis syndrome ，IC values of other signals of L-ASP were higher than those of PEG-ASP. The results of time scanning spectrum showed that the signals of necrotic pancreatitis and coagulation disorder of PEG-ASP were stable ，while the signals of veno occlusive liver disease and hypersensitivity were unstable and needed to be observed ；above four signals of L-ASP were stable signals. When using PEG-ASP or L-ASP clinically ， close attention should be paid to the safety problems such as hypersensitivity ，coagulation disorder ，thrombosis，necrotic pancreatitis，venoocclusive liver disease and hypoproteinemia.

Mechanistic studies of PEG-asparaginase-induced liver injury and hepatic steatosis in mice

PEGylated-l-asparaginase (PEG-ASNase) is a chemotherapeutic agent used to treat pediatric acute lymphoblastic leukemia (ALL). Its use is avoided in adults due to its high risk of liver injury including hepatic steatosis, with obesity and older age considered risk factors of the injury. Our study aims to elucidate the mechanism of PEG-ASNase-induced liver injury. Mice received 1500 U/kg of PEG-ASNase and were sacrificed 1, 3, 5, and 7 days after drug administration. Liver triglycerides were quantified, and plasma bilirubin, ALT, AST, and non-esterified fatty acids (NEFA) were measured. The mRNA and protein levels of genes involved in hepatic fatty acid synthesis,