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1.
Int J Mol Sci ; 22(19)2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34639195

RESUMO

PriB is a primosomal protein required for the replication fork restart in bacteria. Although PriB shares structural similarity with SSB, they bind ssDNA differently. SSB consists of an N-terminal ssDNA-binding/oligomerization domain (SSBn) and a flexible C-terminal protein-protein interaction domain (SSBc). Apparently, the largest difference in structure between PriB and SSB is the lack of SSBc in PriB. In this study, we produced the chimeric PriB-SSBc protein in which Klebsiella pneumoniae PriB (KpPriB) was fused with SSBc of K. pneumoniae SSB (KpSSB) to characterize the possible SSBc effects on PriB function. The crystal structure of KpSSB was solved at a resolution of 2.3 Å (PDB entry 7F2N) and revealed a novel 114-GGRQ-117 motif in SSBc that pre-occupies and interacts with the ssDNA-binding sites (Asn14, Lys74, and Gln77) in SSBn. As compared with the ssDNA-binding properties of KpPriB, KpSSB, and PriB-SSBc, we observed that SSBc could significantly enhance the ssDNA-binding affinity of PriB, change the binding behavior, and further stimulate the PriA activity (an initiator protein in the pre-primosomal step of DNA replication), but not the oligomerization state, of PriB. Based on these experimental results, we discuss reasons why the properties of PriB can be retrofitted when fusing with SSBc.

2.
Sci Data ; 8(1): 265, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34645804

RESUMO

Illumina RNA-seq analysis was used to characterize the whole transcriptomes of peripheral blood mononuclear cells (PBMCs) from patients with congenital generalized lipodystrophy. RNA-seq information for seven patients with type 2 congenital generalized lipodystrophy (CGL2; Berardinelli-Seip congenital lipodystrophy, BSCL2) was obtained and compared with similar information for seven age- and sex-matched healthy control subjects. All seven CGL2 patients carried biallelic pathogenic mutations affecting the BSCL2 gene and had clinical symptoms of varying severity. The findings provide the whole-transcriptome signatures of PBMCs of CGL2 patients, allowing further exploration of gene expression patterns/signatures associated with the various clinical symptoms of patients with this disease.

3.
J Cell Mol Med ; 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34651424

RESUMO

Breast cancer, a hormone-dependent tumour, generally includes four molecular subtypes (luminal A, luminal B, HER2 enriched and triple-negative) based on oestrogen receptor, progesterone receptor and human epidermal growth factor receptor-2. Multiple hormones in the body regulate the development of breast cancer. Endocrine therapy is one of the primary treatments for hormone-receptor-positive breast cancer, but endocrine resistance is the primary clinical cause of treatment failure. Prolactin (PRL) is a protein hormone secreted by the pituitary gland, mainly promoting mammary gland growth, stimulating and maintaining lactation. Previous studies suggest that high PRL levels can increase the risk of invasive breast cancer in women. The expression levels of PRL and PRLR in breast cancer cells and breast cancer tissues are elevated in most ER+ and ER- tumours. PRL activates downstream signalling pathways and affects endocrine therapy resistance by combining with prolactin receptor (PRLR). In this review, we illustrated and summarized the correlations between endocrine therapy resistance in breast cancer and PRL, as well as the pathophysiological mechanisms and clinical practices. The study on PRL and its receptor would help explore reversing endocrine therapy-resistance for breast cancer.

4.
Chromosome Res ; 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34480269

RESUMO

In addition to causing the nondisjunction of maize B and normal A chromosomes at the second megaspore division during embryo sac development, the r-X1 deletion results in terminal deficiencies (TDs) in various A chromosomal arms, but whether the r-X1 deletion also induces TDs of the maize B chromosome remains unknown. To answer this question, the chromosomal composition in the r-X1-containing progeny of r-X1/R-r female parents carrying two standard B chromosomes was determined. Nine of 104 (8.7%) examined kernels contained a smaller telocentric B chromosome, and one of these (designated Bdef-1) was further identified as a TD with a breakpoint in the third distal heterochromatic region of the B chromosome. Thus, the results indicated that the r-X1 deletion could also induce TDs of the maize B chromosome during megaspore divisions. The Bdef-1 chromosome lacked nondisjunctional behavior, and this behavior was restored by the presence of the B chromosome in the cell. A transmission analysis of the Bdef-1 chromosome revealed that loss of the distal portion of the B chromosome reduced female but not male transmission of the B chromosome. Furthermore, the Bdef-1 chromosome was used to more finely map B-derived miRNA genes on the B chromosome. Our results indicate that the r-X1 deletion results in TDs of the B chromosome in maize, and the r-X1 deletion system can thus be used to generate a series of terminally truncated B chromosomes that may be used to map features of the B chromosome, including genes and properties related to B chromosome functions.

5.
Molecules ; 26(18)2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34577034

RESUMO

Cyclotides have attracted great interest as drug design scaffolds because of their unique cyclic cystine knotted topology. They are classified into three subfamilies, among which the bracelet subfamily represents the majority and comprises the most bioactive cyclotides, but are the most poorly utilized in drug design applications. A long-standing challenge has been the very low in vitro folding yields of bracelets, hampering efforts to characterize their structures and activities. Herein, we report substantial increases in bracelet folding yields enabled by a single point mutation of residue Ile-11 to Leu or Gly. We applied this discovery to synthesize mirror image enantiomers and used quasi-racemic crystallography to elucidate the first crystal structures of bracelet cyclotides. This study provides a facile strategy to produce bracelet cyclotides, leading to a general method to easily access their atomic resolution structures and providing a basis for development of biotechnological applications.

6.
Cancers (Basel) ; 13(15)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34359714

RESUMO

The role of a YAP-IGF-1R signaling loop in HCC resistance to sorafenib remains unknown. METHOD: Sorafenib-resistant cells were generated by treating naïve cells (HepG2215 and Hep3B) with sorafenib. Different cancer cell lines from databases were analyzed through the ONCOMINE web server. BIOSTORM-LIHC patient tissues (46 nonresponders and 21 responders to sorafenib) were used to compare YAP mRNA levels. The HepG2215_R-derived xenograft in SCID mice was used as an in vivo model. HCC tissues from a patient with sorafenib failure were used to examine differences in YAP and IGF-R signaling. RESULTS: Positive associations exist among the levels of YAP, IGF-1R, and EMT markers in HCC tissues and the levels of these proteins increased with sorafenib failure, with a trend of tumor-margin distribution in vivo. Blocking YAP downregulated IGF-1R signaling-related proteins, while IGF-1/2 treatment enhanced the nuclear translocation of YAP in HCC cells through PI3K-mTOR regulation. The combination of YAP-specific inhibitor verteporfin (VP) and sorafenib effectively decreased cell viability in a synergistic manner, evidenced by the combination index (CI). CONCLUSION: A YAP-IGF-1R signaling loop may play a role in HCC sorafenib resistance and could provide novel potential targets for combination therapy with sorafenib to overcome drug resistance in HCC.

8.
Stem Cell Res Ther ; 12(1): 380, 2021 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-34215319

RESUMO

BACKGROUND: Small blood stem cells (SB cells), isolated from human peripheral blood, demonstrated the ability to benefit bone regeneration and osseointegration. The primary goal of our study is to examine the safety and tolerability of SB cells in dental implantation for human patients with severe bone defects. METHODS: Nine patients were enrolled and divided into three groups with SB cell treatment doses of 1 × 105, 1 × 106, and 1 × 107 SB cells, and then evaluated by computed tomography (CT) scans to assess bone mineral density (BMD) by Hounsfield units (HU) scoring. Testing was conducted before treatment and on weeks 4, 6, 8, and 12 post dental implantation. Blood and comprehensive chemistry panel testing were also performed. RESULTS: No severe adverse effects were observed for up to 6-month trial. Grade 1 leukocytosis, anemia, and elevated liver function were observed, but related with the patient's condition or the implant treatment itself and not the transplantation of SB cells. The levels of cytokines and chemokines were detected by a multiplex immunological assay. Elevated levels of eotaxin, FGF2, MCP-1, MDC, and IL17a were found among patients who received SB cell treatment. This observation suggested SB cells triggered cytokines and chemokines for local tissue repair. To ensure the efficacy of SB cells in dental implantation, the BMD and maximum stresses via stress analysis model were measured through CT scanning. All patients who suffered from severe bone defect showed improvement from D3 level to D1 or D2 level. The HU score acceleration can be observed by week 2 after guided bone regeneration (GBR) and prior to dental implantation. CONCLUSIONS: This phase I study shows that treatment of SB cells for dental implantation is well tolerated with no major adverse effects. The use of SB cells for accelerating the osseointegration in high-risk dental implant patients warrants further phase II studies. TRIAL REGISTRATION: Taiwan Clinical Trial Registry ( SB-GBR001 ) and clinical trial registry of the United States ( NCT04451486 ).


Assuntos
Implantes Dentários , Osseointegração , Densidade Óssea , Regeneração Óssea , Humanos , Células-Tronco
9.
Int J Mol Sci ; 22(12)2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-34200975

RESUMO

Hereditary anemia has various manifestations, such as sickle cell disease (SCD), Fanconi anemia, glucose-6-phosphate dehydrogenase deficiency (G6PDD), and thalassemia. The available management strategies for these disorders are still unsatisfactory and do not eliminate the main causes. As genetic aberrations are the main causes of all forms of hereditary anemia, the optimal approach involves repairing the defective gene, possibly through the transplantation of normal hematopoietic stem cells (HSCs) from a normal matching donor or through gene therapy approaches (either in vivo or ex vivo) to correct the patient's HSCs. To clearly illustrate the importance of cell and gene therapy in hereditary anemia, this paper provides a review of the genetic aberration, epidemiology, clinical features, current management, and cell and gene therapy endeavors related to SCD, thalassemia, Fanconi anemia, and G6PDD. Moreover, we expound the future research direction of HSC derivation from induced pluripotent stem cells (iPSCs), strategies to edit HSCs, gene therapy risk mitigation, and their clinical perspectives. In conclusion, gene-corrected hematopoietic stem cell transplantation has promising outcomes for SCD, Fanconi anemia, and thalassemia, and it may overcome the limitation of the source of allogenic bone marrow transplantation.


Assuntos
Anemia/terapia , Terapia Baseada em Transplante de Células e Tecidos/métodos , Edição de Genes , Terapia Genética/métodos , Transplante de Células-Tronco Hematopoéticas/métodos , Células-Tronco Hematopoéticas/citologia , Anemia/genética , Animais , Humanos
10.
Int J Mol Sci ; 22(13)2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34202294

RESUMO

Dihydroorotase (DHOase) is the third enzyme in the de novo biosynthesis pathway for pyrimidine nucleotides, and an attractive target for potential anticancer chemotherapy. By screening plant extracts and performing GC-MS analysis, we identified and characterized that the potent anticancer drug plumbagin (PLU), isolated from the carnivorous plant Nepenthes miranda, was a competitive inhibitor of DHOase. We also solved the complexed crystal structure of yeast DHOase with PLU (PDB entry 7CA1), to determine the binding interactions and investigate the binding modes. Mutational and structural analyses indicated the binding of PLU to DHOase through loop-in mode, and this dynamic loop may serve as a drug target. PLU exhibited cytotoxicity on the survival, migration, and proliferation of 4T1 cells and induced apoptosis. These results provide structural insights that may facilitate the development of new inhibitors targeting DHOase, for further clinical anticancer chemotherapies.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Produtos Biológicos/farmacologia , Vias Biossintéticas/efeitos dos fármacos , Di-Hidro-Orotase/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Naftoquinonas/farmacologia , Pirimidinas/biossíntese , Antineoplásicos Fitogênicos/química , Sítios de Ligação , Produtos Biológicos/química , Domínio Catalítico , Di-Hidro-Orotase/química , Di-Hidro-Orotase/genética , Inibidores Enzimáticos/química , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Mutação , Naftoquinonas/química , Ligação Proteica , Relação Estrutura-Atividade
11.
Int J Mol Sci ; 22(14)2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34298988

RESUMO

This study evaluated the biocompatibility and biological performance of novel additive-manufactured bioabsorbable iron-based porous suture anchors (iron_SAs). Two types of bioabsorbable iron_SAs, with double- and triple-helical structures (iron_SA_2_helix and iron_SA_3_helix, respectively), were compared with the synthetic polymer-based bioabsorbable suture anchor (polymer_SAs). An in vitro mechanical test, MTT assay, and scanning electron microscope (SEM) analysis were performed. An in vivo animal study was also performed. The three types of suture anchors were randomly implanted in the outer cortex of the lateral femoral condyle. The ultimate in vitro pullout strength of the iron_SA_3_helix group was significantly higher than the iron_SA_2_helix and polymer_SA groups. The MTT assay findings demonstrated no significant cytotoxicity, and the SEM analysis showed cells attachment on implant surface. The ultimate failure load of the iron_SA_3_helix group was significantly higher than that of the polymer_SA group. The micro-CT analysis indicated the iron_SA_3_helix group showed a higher bone volume fraction (BV/TV) after surgery. Moreover, both iron SAs underwent degradation with time. Iron_SAs with triple-helical threads and a porous structure demonstrated better mechanical strength and high biocompatibility after short-term implantation. The combined advantages of the mechanical superiority of the iron metal and the possibility of absorption after implantation make the iron_SA a suitable candidate for further development.


Assuntos
Implantes Absorvíveis , Materiais Biocompatíveis , Âncoras de Sutura , Alanina Transaminase/sangue , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/toxicidade , Fenômenos Biomecânicos , Nitrogênio da Ureia Sanguínea , Fosfatos de Cálcio/química , Fosfatos de Cálcio/toxicidade , Sulfato de Cálcio/administração & dosagem , Sulfato de Cálcio/química , Sulfato de Cálcio/toxicidade , Creatinina/sangue , Desenho de Equipamento , Fêmur/diagnóstico por imagem , Fêmur/ultraestrutura , Ferro , Lasers , Teste de Materiais , Microscopia Eletrônica de Varredura , Estrutura Molecular , Osseointegração , Polímeros/química , Polímeros/toxicidade , Porosidade , Coelhos , Distribuição Aleatória , Resistência à Tração , Vísceras , Microtomografia por Raio-X
12.
Atherosclerosis ; 330: 52-60, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34246818

RESUMO

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a clinically validated target for treating cardiovascular disease (CVD) due to its involvement in cholesterol metabolism. Although approved monoclonal antibodies (alirocumab and evolocumab) that inhibit PCSK9 function are very effective in lowering cholesterol, their limitations, including high treatment costs, have so far prohibited widespread use. Accordingly, there is great interest in alternative drug modalities to antibodies. Like antibodies, peptides are valuable therapeutics due to their high target potency and specificity. Furthermore, being smaller than antibodies means they have access to more drug administration options, are less likely to induce adverse immunogenic responses, and are better suited to affordable production. This review surveys the current peptide-based landscape aimed towards PCSK9 inhibition, covering pre-clinical to patented drug candidates and comparing them to current cholesterol lowering therapeutics. Classes of peptides reported to be inhibitors include nature-inspired disulfide-rich peptides, combinatorially derived cyclic peptides, and peptidomimetics. Their functional activities have been validated in biophysical and cellular assays, and in some cases pre-clinical mouse models. Recent efforts report peptides with potent sub-nanomolar binding affinities to PCSK9, which highlights their potential to achieve antibody-like potency. Studies are beginning to address pharmacokinetic properties of PCSK9-targeting peptides in more detail. We conclude by highlighting opportunities to investigate their biological effects in pre-clinical models of cardiovascular disease. The anticipation concerning the PCSK9-targeting peptide landscape is accelerating and it seems likely that a peptide-based therapeutic for treating PCSK9-mediated hypercholesterolemia may be clinically available in the near future.


Assuntos
Anticolesterolemiantes , Hipercolesterolemia , Animais , Anticorpos Monoclonais , Humanos , Hipercolesterolemia/tratamento farmacológico , Camundongos , Peptídeos , Pró-Proteína Convertase 9
13.
ACS Chem Biol ; 16(7): 1276-1287, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-34152716

RESUMO

Inhibiting the Nrf2:Keap1 interaction to trigger cytoprotective gene expression is a promising treatment strategy for oxidative stress-related diseases. A short linear motif from Nrf2 has the potential to directly inhibit this protein-protein interaction, but poor stability and limited cellular uptake impede its therapeutic development. To address these limitations, we utilized an integrated molecular grafting strategy to re-engineer the Nrf2 motif. We combined the motif with an engineered non-native disulfide bond and a cell-penetrating peptide onto a single multifunctionalizable and ultrastable molecular scaffold, namely, the cyclotide MCoTI-II, resulting in the grafted peptide MCNr-2c. The engineered disulfide bond enhanced the conformational rigidity of the motif, resulting in a nanomolar affinity of MCNr-2c for Keap1. The cell-penetrating peptide led to an improved cellular uptake and increased ability to enhance the intracellular expression of two well-described Nrf2-target genes NQO1 and TALDO1. Furthermore, the stability of the scaffold was inherited by the grafted peptide, which became resistant to proteolysis in serum. Overall, we have provided proof-of-concept for a strategy that enables the encapsulation of multiple desired and complementary activities into a single molecular entity to design a Keap1-targeted inhibitor. We propose that this integrated approach could have broad utility for the design of peptide drug leads that require multiple functions and/or biopharmaceutical properties to elicit a therapeutic activity.


Assuntos
Peptídeos Penetradores de Células/farmacologia , Ciclotídeos/farmacologia , Proteína 1 Associada a ECH Semelhante a Kelch/antagonistas & inibidores , Sequência de Aminoácidos , Sangue/metabolismo , Peptídeos Penetradores de Células/química , Ciclotídeos/química , Desenho de Fármacos , Células HeLa , Humanos , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Masculino , Fator 2 Relacionado a NF-E2/química , Fator 2 Relacionado a NF-E2/metabolismo , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/farmacologia , Estudo de Prova de Conceito , Ligação Proteica/efeitos dos fármacos , Estabilidade Proteica
14.
Proc Biol Sci ; 288(1952): 20210582, 2021 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-34074118

RESUMO

When a transmission hotspot for an environmentally persistent pathogen establishes in otherwise high-quality habitat, the disease may exert a strong impact on a host population. However, fluctuating environmental conditions lead to heterogeneity in habitat quality and animal habitat preference, which may interrupt the overlap between selected and risky habitats. We evaluated spatio-temporal patterns in anthrax mortalities in a plains zebra (Equus quagga) population in Etosha National Park, Namibia, incorporating remote-sensing and host telemetry data. A higher proportion of anthrax mortalities of herbivores was detected in open habitats than in other habitat types. Resource selection functions showed that the zebra population shifted habitat selection in response to changes in rainfall and vegetation productivity. Average to high rainfall years supported larger anthrax outbreaks, with animals congregating in preferred open habitats, while a severe drought forced animals into otherwise less preferred habitats, leading to few anthrax mortalities. Thus, the timing of anthrax outbreaks was congruent with preference for open plains habitats and a corresponding increase in pathogen exposure. Given shifts in habitat preference, the overlap in high-quality habitat and high-risk habitat is intermittent, reducing the adverse consequences for the population.


Assuntos
Antraz , Equidae , Animais , Secas , Ecossistema , Namíbia
15.
Sci Rep ; 11(1): 11189, 2021 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-34045621

RESUMO

Since 2013, a high incidence of bilateral symmetrical alopecia has been observed in free-ranging Formosan macaques (Macaca cyclopis) in Mt. Longevity, Taiwan. We hypothesized that stress induces alopecia in this population. To verify our hypothesis, we evaluated the histopathological characteristics of skin biopsy and used a validated enzyme immunoassay (EIA) for fecal glucocorticoid metabolite (FGM) analysis, which act as an indicator of stress experienced by the individual. Follicular densities were lower (2.1-3.0 mm2) in individuals with symmetrical alopecia than in those with normal hair conditions (4.7 mm2). Furthermore, anagen to catagen/telogen ratios were lower in individuals with alopecia (0-1.4) than in those with normal hair (4.0). The histopathological characteristics of alopecia were similar to those of telogen effluvium, which indicates that stress is one of the possible etiologies. On the basis of the analytical and biological validation of EIAs for FGM analysis, 11ß-hydroxyetiocholanolone was considered suitable for monitoring adrenocortical activity in both sexes of Formosan macaques. The mean concentrations (standard error; sample size) of 11ß-hydroxyetiocholanolone were 2.02 (0.17; n = 10) and 1.41 (0.10; n = 31) µg/g for individuals with and without alopecia, respectively. Furthermore, the results of logistic regression analysis show that 11ß-hydroxyetiocholanolone (p = 0.012) concentration was positively associated with alopecia. Thus, stress was the most likely to trigger symmetrical alopecia in Formosan macaques in Mt. Longevity. Although stress can decrease the fitness of an individual, considering the population status of Formosan macaques in Taiwan is stable and alopecia was only observed in our study area, which is isolated from other populations, the impact on the total population of Formosan macaque in Taiwan is limited. Nonetheless, stress-induced immunosuppression and alopecia might affect the local abundance and increase zoonosis risk due to frequent human-macaque contact in Mt. Longevity. Future studies are suggested to focus on the causative factor of stress and the effects of stress and alopecia on the health and welfare in the Formosan macaques.

16.
J Biomed Sci ; 28(1): 28, 2021 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-33849537

RESUMO

Mesenchymal stem/stromal cells (MSCs) are a promising resource for cell-based therapy because of their high immunomodulation ability, tropism towards inflamed and injured tissues, and their easy access and isolation. Currently, there are more than 1200 registered MSC clinical trials globally. However, a lack of standardized methods to characterize cell safety, efficacy, and biodistribution dramatically hinders the progress of MSC utility in clinical practice. In this review, we summarize the current state of MSC-based cell therapy, focusing on the systemic safety and biodistribution of MSCs. MSC-associated risks of tumor initiation and promotion and the underlying mechanisms of these risks are discussed. In addition, MSC biodistribution methodology and the pharmacokinetics and pharmacodynamics of cell therapies are addressed. Better understanding of the systemic safety and biodistribution of MSCs will facilitate future clinical applications of precision medicine using stem cells.


Assuntos
Transplante de Células-Tronco Mesenquimais/estatística & dados numéricos , Células-Tronco Mesenquimais/fisiologia , Humanos
17.
Methods Mol Biol ; 2281: 67-80, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33847952

RESUMO

Single-stranded DNA (ssDNA)-binding protein (SSB) is essential for DNA metabolic processes. SSB also binds to many DNA-binding proteins that constitute the SSB interactome. The mechanism through which PriA helicase, an initiator protein in the DNA replication restart process, is stimulated by SSB in Escherichia coli (EcSSB) has been established. However, some Gram-positive bacterial SSBs such as Bacillus subtilis SsbA (a counterpart of EcSSB), Staphylococcus aureus SsbA, SsbB, and SsbC do not activate PriA helicase. Here, we describe some of the methods used in our laboratory to compare SSB-PriA functional and physical interactions in Gram-positive and -negative bacteria.


Assuntos
Bacillus subtilis/metabolismo , DNA Helicases/metabolismo , Proteínas de Ligação a DNA/metabolismo , Escherichia coli/metabolismo , Staphylococcus aureus/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Sítios de Ligação , DNA Helicases/química , Proteínas de Ligação a DNA/química , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Modelos Moleculares , Ligação Proteica , Análise de Sequência de Proteína , Especificidade da Espécie , Ressonância de Plasmônio de Superfície
18.
Hepatology ; 74(2): 641-655, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33675094

RESUMO

BACKGROUND AND AIMS: PreS mutants of HBV have been reported to be associated with HCC. We conducted a longitudinal study of the role of HBV preS mutations in the development of HCC, particularly in patients with chronic hepatitis B (CHB) having low HBV DNA or alanine aminotransferase (ALT) levels, and investigated the effects of secretion-defective preS2 deletion mutant (preS2ΔMT) on hepatocyte damage in vitro and liver fibrosis in vivo. APPROACH AND RESULTS: Association of preS mutations with HCC in 343 patients with CHB was evaluated by a retrospective case-control follow-up study. Effects of preS2ΔMT on HBsAg retention, endoplasmic reticulum (ER) stress, calcium accumulation, mitochondrial dysfunction, and liver fibrosis were examined. Multivariate analysis revealed a significant association of preS mutations with HCC (HR, 3.210; 95% CI, 1.072-9.613; P = 0.037) including cases with low HBV DNA or ALT levels (HR, 2.790; 95% CI, 1.133-6.873; P = 0.026). Antiviral therapy reduced HCC risk, including cases with preS mutations. PreS2ΔMT expression promoted HBsAg retention in the ER and unfolded protein response (UPR). Transmission electron microscopic examination, MitoTracker staining, real-time ATP assay, and calcium staining of preS2ΔMT-expressing cells revealed aberrant ER and mitochondrial ultrastructure, reduction of mitochondrial membrane potential and ATP production, and calcium overload. Serum HBV secretion levels were ~100-fold lower in preS2ΔMT-infected humanized Fah-/-/ Rag2-/-/Il2rg-/- triple knockout mice than in wild-type HBV-infected mice. PreS2ΔMT-infected mice displayed up-regulation of UPR and caspase-3 and enhanced liver fibrosis. CONCLUSIONS: PreS mutations were significantly associated with HCC development in patients with CHB, including those with low HBV DNA or ALT levels. Antiviral therapy reduced HCC occurrence in patients with CHB, including those with preS mutations. Intracellular accumulation of mutated HBsAg induced or promoted ER stress, calcium overload, mitochondrial dysfunction, impaired energy metabolism, liver fibrosis, and HCC.

19.
Biochem Biophys Res Commun ; 551: 33-37, 2021 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-33714757

RESUMO

Dihydroorotase (DHOase) is the third enzyme in the de novo biosynthesis pathway of pyrimidine nucleotides and considered an attractive target for potential antimalarial, anticancer, and antipathogen chemotherapy. Whether the FDA-approved clinical drug 5-fluorouracil (5-FU) that is used to target the enzyme thymidylate synthase for anticancer therapy can also bind to DHOase remains unknown. Here, we report the crystal structures of DHOase from Saccharomyces cerevisiae (ScDHOase) complexed with malate, 5-FU, and 5-aminouracil (5-AU). ScDHOase shares structural similarity with Escherichia coli DHOase. We also characterized the binding of 5-FU and 5-AU to ScDHOase by using the fluorescence quenching method. These complexed structures revealed that residues Arg18, Asn43, Thr106, and Ala275 of ScDHOase were involved in the 5-FU (PDB entry 6L0B) and 5-AU binding (PDB entry 6L0F). Overall, these results provide structural insights that may facilitate the development of new inhibitors targeting DHOase and constitute the 5-FU and 5-AU interactomes for further clinical chemotherapies.


Assuntos
Antineoplásicos/química , Di-Hidro-Orotase/química , Fluoruracila/química , Saccharomyces cerevisiae/enzimologia , Uracila/análogos & derivados , Antineoplásicos/farmacologia , Sítios de Ligação , Cristalização , Cristalografia por Raios X , Di-Hidro-Orotase/metabolismo , Escherichia coli/enzimologia , Fluoruracila/farmacologia , Malatos/química , Modelos Moleculares , Ligação Proteica , Uracila/química , Uracila/farmacologia
20.
Int J Mol Sci ; 22(4)2021 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-33669204

RESUMO

Insulin-like Growth Factor (IGF)/IGF-1 Receptor (IGF-1R) signaling is known to regulate stem cell pluripotency and differentiation to trigger cell proliferation, organ development, and tissue regeneration during embryonic development. Unbalanced IGF/IGF-1R signaling can promote cancer cell proliferation and activate cancer reprogramming in tumor tissues, especially in the liver. Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death, with a high incidence and mortality rate in Asia. Most patients with advanced HCC develop tyrosine kinase inhibitor (TKI)-refractoriness after receiving TKI treatment. Dysregulation of IGF/IGF-1R signaling in HCC may activate expression of cancer stemness that leads to TKI refractoriness and tumor recurrence. In this review, we summarize the evidence for dysregulated IGF/IGF-1R signaling especially in hepatitis B virus (HBV)-associated HCC. The regulation of cancer stemness expression and drug resistance will be highlighted. Current clinical treatments and potential therapies targeting IGF/IGF-1R signaling for the treatment of HCC will be discussed.


Assuntos
Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , Receptor IGF Tipo 1/metabolismo , Transdução de Sinais , Somatomedinas/metabolismo , Carcinoma Hepatocelular/complicações , Carcinoma Hepatocelular/tratamento farmacológico , Citocinas/metabolismo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Hepatite B/complicações , Hepatite B/metabolismo , Hepatite B/virologia , Vírus da Hepatite B/fisiologia , Humanos , Neoplasias Hepáticas/complicações , Neoplasias Hepáticas/tratamento farmacológico , Terapia de Alvo Molecular/métodos , Recidiva Local de Neoplasia , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Receptor IGF Tipo 1/antagonistas & inibidores , Replicação Viral
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