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Dormant hematopoietic stem cells (dHSCs) are atop the hematopoietic hierarchy. The molecular identity of dHSCs and the mechanisms regulating their maintenance or exit from dormancy remain uncertain. Here, we use single-cell RNA sequencing (RNA-seq) analysis to show that the transition from dormancy toward cell-cycle entry is a continuous developmental path associated with upregulation of biosynthetic processes rather than a stepwise progression. In addition, low Myc levels and high expression of a retinoic acid program are characteristic for dHSCs. To follow the behavior of dHSCs in situ, a Gprc5c-controlled reporter mouse was established. Treatment with all-trans retinoic acid antagonizes stress-induced activation of dHSCs by restricting protein translation and levels of reactive oxygen species (ROS) and Myc. Mice maintained on a vitamin A-free diet lose HSCs and show a disrupted re-entry into dormancy after exposure to inflammatory stress stimuli. Our results highlight the impact of dietary vitamin A on the regulation of cell-cycle-mediated stem cell plasticity. VIDEO ABSTRACT.
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Células-Tronco Hematopoéticas/citologia , Transdução de Sinais , Tretinoína/farmacologia , Vitamina A/administração & dosagem , Animais , Vias Biossintéticas , Técnicas de Cultura de Células , Ciclo Celular/efeitos dos fármacos , Sobrevivência Celular , Dieta , Perfilação da Expressão Gênica , Células-Tronco Hematopoéticas/efeitos dos fármacos , Camundongos , Poli I-C/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Análise de Célula Única , Estresse Fisiológico , Vitamina A/farmacologia , Vitaminas/administração & dosagem , Vitaminas/farmacologiaRESUMO
All-trans-retinoic acid (ATRA) and arsenic trioxide (ATO) represent the standard of care for low-intermediate risk acute promyelocytic leukaemia (APL). Leucocytosis during induction with ATRA-ATO represents a common complication with an incidence of up to 60%. To identify predictive factors for this complication, we studied a cohort of 65 low-intermediate risk APL patients treated with ATRA-ATO in three highly specialized Italian centres. Overall, 39/65 (60%) patients developed leucocytosis, with a peak in leucocyte count being most frequent in the second week from diagnosis. All cases were successfully managed with hydroxyurea. Predictive factors for leucocytosis in univariate analysis were lower platelet counts (odds ratio [OR] 0.98, 0.97-1.00, p = 0.018), lower fibrinogen levels (OR 0.36, 0.17-0.66, p = 0.003), higher bone marrow blast infiltration (OR 1.03, 1.01-1.07, p = 0.021) and CD117 expression by flow (OR 1.04, 1.01-1.08, p = 0.012). Multivariate analysis confirmed lower levels of fibrinogen at diagnosis as the strongest predictive factor for the development of leucocytosis (OR 0.36, 0.15-0.72, p = 0.009). Differentiation syndrome (DS) occurred only in patients developing leucocytosis showing a strict correlation with rising leucocytes counts (16/39 vs. 0/26, p < 0.001). In addition, other treatment-related complications including QTc prolongation, cardiac events, liver, and haematological toxicities were significantly more frequent in patients experiencing leucocytosis (22/39 vs. 3/26, p < 0.001). In conclusion, APL patients undergoing ATRA-ATO therapy with lower fibrinogen levels and platelet counts at diagnosis and with a massive bone marrow blast infiltrate should be carefully monitored for the development of leucocytosis during induction. DS and other treatment-related complications seem to occur almost exclusively in patients developing leucocytosis, who should necessarily receive DS prophylaxis and more intensive monitoring and supportive therapy to prevent treatment complications.
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Naja atra, the Chinese cobra, is a major cause of snake envenomation in Asia, causing hundreds of thousands of clinical incidents annually. The current treatment, horse serum-derived antivenom, has unpredictable side effects and presents manufacturing challenges. This study focused on developing new-generation snake venom antidotes by using microbial phage display technology to derive nanobodies from an alpaca immunized with attenuated N. atra venom. Following confirmation of the immune response in the alpaca, we amplified VHH genes from isolated peripheral blood mononuclear cells and constructed a phage display VHH library of 1.0 × 107 transformants. After four rounds of biopanning, the enriched phages exhibited increased binding activity to N. atra venom. Four nanobody clones with high binding affinities were selected: aNAH1, aNAH6, aNAH7, and aNAH9. Specificity testing against venom from various snake species, including two Southeast Asian cobra species, revealed nanobodies specific to the genus Naja. An in vivo mouse venom neutralization assay demonstrated that all nanobodies prolonged mouse survival and aNAH6 protected 66.6% of the mice from the lethal dosage. These findings highlight the potential of phage display-derived nanobodies as valuable antidotes for N. atra venom, laying the groundwork for future applications in snakebite treatment.IMPORTANCEChinese cobra venom bites present a formidable medical challenge, and current serum treatments face unresolved issues. Our research applied microbial phage display technology to obtain a new, effective, and cost-efficient treatment approach. Despite interest among scientists in utilizing this technology to screen alpaca antibodies against toxins, the available literature is limited. This study makes a significant contribution by introducing neutralizing antibodies that are specifically tailored to Chinese cobra venom. We provide a comprehensive and unbiased account of the antibody construction process, accompanied by thorough testing of various nanobodies and an assessment of cross-reactivity with diverse snake venoms. These nanobodies represent a promising avenue for targeted antivenom development that bridges microbiology and biotechnology to address critical health needs.
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Antivenenos , Camelídeos Americanos , Venenos Elapídicos , Anticorpos de Domínio Único , Mordeduras de Serpentes , Animais , Anticorpos de Domínio Único/imunologia , Camundongos , Mordeduras de Serpentes/terapia , Mordeduras de Serpentes/imunologia , Antivenenos/imunologia , Venenos Elapídicos/imunologia , Técnicas de Visualização da Superfície Celular , Naja naja , Biblioteca de PeptídeosRESUMO
In many autoimmune diseases, autoantigen-specific Th17 cells play a pivotal role in disease pathogenesis. Th17 cells can transdifferentiate into other T cell subsets in inflammatory conditions, however, there have been no attempts to target Th17 cell plasticity using vaccines. We investigated if autoantigen-specific Th17 cells could be specifically targeted using a therapeutic vaccine approach, where antigen was formulated in all-trans retinoic acid (ATRA)-containing liposomes, permitting co-delivery of antigen and ATRA to the same target cell. Whilst ATRA was previously found to broadly reduce Th17 responses, we found that antigen formulated in ATRA-containing cationic liposomes only inhibited Th17 cells in an antigen-specific manner and not when combined with an irrelevant antigen. Furthermore, this approach shifted existing Th17 cells away from IL-17A expression and transcriptomic analysis of sorted Th17 lineage cells from IL-17 fate reporter mice revealed a shift of antigen-specific Th17 cells to exTh17 cells, expressing functional markers associated with T cell regulation and tolerance. In the experimental autoimmune encephalomyelitis (EAE) mouse model of MS, vaccination with myelin-specific (MOG) antigen in ATRA-containing liposomes reduced Th17 responses and alleviated disease. This highlights the potential of therapeutic vaccination for changing the phenotype of existing Th17 cells in the context of immune mediated diseases.
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Encefalomielite Autoimune Experimental , Células Th17 , Camundongos , Animais , Lipossomos/metabolismo , Tretinoína/farmacologia , Tretinoína/metabolismo , Autoantígenos/metabolismo , Adjuvantes Imunológicos , Imunização , Vacinação , Fenótipo , Camundongos Endogâmicos C57BL , Células Th1RESUMO
Light-mediated processes have received significant attention, since they have re-surfaced unconventional reactivity platforms, complementary to conventional polar chemistry. γ-Lactones and cyclopropanes are prevalent moieties, found in numerous natural products and pharmaceuticals. Among various methods for their synthesis, light-mediated protocols are coming to the spotlight, although these are contingent upon the use of photoorgano- or metal-based catalysts. Herein, we introduce a novel photochemical activation of iodo-reagents via the use of cheap sodium ascorbate or ascorbic acid to enable their homolytic scission and addition onto double bonds. The developed protocol was applied successfully to the formal [3+2] cycloaddition for the synthesis of γ-lactones, traditional atom transfer radical addition (ATRA) reactions and the one-pot two-step conversion of alkenes to cyclopropanes. In all cases, the desired products were obtained in good to high yields, while the reaction mechanism was thoroughly investigated. Depending on the nature of the iodo-reagent, a halogen or a hydrogen-bonded complex is formed, which initiates the process.
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A comprehensive analysis of 220 patients diagnosed with APL between 1993 and 2022 is here reported. Overall, 214 patients (97.2%) received induction therapy. Complete response (CR) was achieved in 97.4%, 100%, 100%, and 27% of patients treated with AIDA protocol, AIDA + Ara-C, ATRA + ATO, and ATRA monotherapy, respectively. Molecular complete response (CRMRD-) was achieved in 96.8% cases, and 142 patients proceeded to maintenance therapy. Overall, the 3-year and 5-year overall survival (OS) rates were 80.8% (95% CI, 78.1-83.5) and 79.1% (95% CI, 76.4-81.8), respectively. Considering only patients who completed induction and maintenance therapy, the 5-year OS rates were 82.1% (95% CI, 77.5-86.7) for the AIDA0493 cohort, 87.5% (95% CI, 84.4-91.1) for the AIDA2000 cohort, and 100% for the APL0406 cohort (p = 0.044). Additionally, the disease-free survival (DFS) rates were 65.7% (95% CI, 60.4-70.9), 70% (95% CI, 65.8-75.2), and 95.1% (95% CI, 91.7-98.5) (p = 0.016), respectively. Among low and intermediate-risk patients, age > 70 years (p = 0.027) and relapse (p < 0.001) were significantly associated with reduced outcomes. This study contributes to the advancement of our understanding of APL treatment, underscoring the ongoing need for research to enhance outcomes and explore new therapeutic approaches and prognostic factors.
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Parkinson's disease (PD) is a debilitating and the second most common neurodegenerative disorder with a high prevalence. PD has a multifaceted etiology characterized by an altered redox state and an excessive inflammatory response. Extensive research has consistently demonstrated the role of the nuclear factor E2-related factor (Nrf2) and inflammasomes, notably NLRP3 in neurodegenerative diseases. In this study, our focus was on exploring the potential neuroprotective properties of carveol in Parkinson's disease. Our findings suggest that carveol may exhibit these effects through Nrf2 and by suppressing pyroptosis. Male albino mice were treated with carveol, and the animal PD model was induced through a single intranigral dose of 2 µg/2µl lipopolysaccharide (LPS). To further demonstrate the essential role of the Nrf2 pathway, we utilized all-trans retinoic acid (ATRA) to inhibit the Nrf2. Our finding showed the induction of pyroptosis as evidenced by increased levels of NLRP3 and other inflammatory mediators, including IL-1ß, iNOS, p-NFKB, and apoptotic cell death indicated by positive fluoro Jade B (FJB) staining. Moreover, increased levels of lipid peroxides and reactive oxygen species indicated a significant rise in oxidative stress due to LPS. The administration of carveol mitigates oxidative stress and suppresses inflammatory pathways through the augmentation of intrinsic antioxidant defenses, primarily via the activation of the Nrf2. Conversely, ATRA reversed carveol protective effects by increasing FJB-positive cells, inflammatory and oxidative biomarkers. Taken together, our findings suggest that carveol mitigated LPS-induced Parkinson-like symptoms, partially through the activation of the Nrf2 and downregulation of pyroptosis notably NLRP3.
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Inflamassomos , Fator 2 Relacionado a NF-E2 , Piroptose , Tretinoína , Animais , Fator 2 Relacionado a NF-E2/metabolismo , Piroptose/efeitos dos fármacos , Masculino , Inflamassomos/metabolismo , Inflamassomos/efeitos dos fármacos , Camundongos , Tretinoína/farmacologia , Tretinoína/uso terapêutico , Lipopolissacarídeos , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/uso terapêutico , Doença de Parkinson/metabolismo , Doença de Parkinson/tratamento farmacológicoRESUMO
Persistent infection with high-risk human papillomavirus remains the primary factor associated with the progression of cervical squamous intraepithelial lesions and the development of cervical cancer. Nevertheless, a combination of factors, including genetic predisposition, immune response, hormonal influences, and nutritional status, contribute synergistically to the development of cervical cancer. Among the various factors involved in the pathogenesis and therapy of cervical cancer, retinoids have gained considerable attention due to their multifaceted roles in different cellular processes. This review investigates defects within the vitamin A metabolism pathway and their correlation with cervical cancer. Additionally, it integrates epidemiological and experimental findings to discuss the potential utility of retinoid-based therapies, either alone or combined with other therapies, as agents against premalignant lesions and cervical cancer.
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Lesões Pré-Cancerosas , Retinoides , Neoplasias do Colo do Útero , Humanos , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/virologia , Neoplasias do Colo do Útero/patologia , Feminino , Retinoides/uso terapêutico , Lesões Pré-Cancerosas/tratamento farmacológico , Lesões Pré-Cancerosas/patologia , Infecções por Papillomavirus/complicações , Infecções por Papillomavirus/tratamento farmacológico , Vitamina A/uso terapêuticoRESUMO
In a randomized phase II trial (AMLSG 14-09, NCT00867672) of elderly, newly diagnosed AML patients, ATRA combined with decitabine (DEC) significantly improved the overall response rate (ORR) and survival also in patients with adverse-risk genetics, without adding toxicity. We performed a post hoc analysis to determine the predictive impact of TP53 status. Despite a nominally higher ORR, the clinically meaningful survival benefit when adding ATRA to DEC was diminished, but not completely negated, in TP53-mutated patients. Indeed, 2 out of 14 TP53-mutated patients (14%) randomized to a DEC + ATRA-containing regimen lived for > 36 months. Further studies of ATRA combined with hypomethylating agents appear warranted in non-M3 AML patients ineligible for HMA/venetoclax therapy. Trial Registration: ClinicalTrials.gov identifier: NCT00867672.
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The transformation of acute promyelocytic leukemia (APL) from the most fatal to the most curable subtype of acute myeloid leukemia (AML), with long-term survival exceeding 90%, has represented one of the most exciting successes in hematology and in oncology. APL is a paradigm for oncoprotein-targeted cure.APL is caused by a 15/17 chromosomal translocation which generates the PML-RARA fusion protein and can be cured by the chemotherapy-free approach based on the combination of two therapies targeting PML-RARA: retinoic acid (RA) and arsenic. PML-RARA is the key driver of APL and acts by deregulating transcriptional control, particularly RAR targets involved in self-renewal or myeloid differentiation, also disrupting PML nuclear bodies. PML-RARA mainly acts as a modulator of the expression of specific target genes: genes whose regulatory elements recruit PML-RARA are not uniformly repressed but also may be upregulated or remain unchanged. RA and arsenic trioxide directly target PML-RARA-mediated transcriptional deregulation and protein stability, removing the differentiation block at promyelocytic stage and inducing clinical remission of APL patients.
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Leucemia Promielocítica Aguda , Proteínas de Fusão Oncogênica , Tretinoína , Humanos , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/tratamento farmacológico , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/patologia , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Tretinoína/uso terapêutico , Tretinoína/farmacologia , Trióxido de Arsênio/uso terapêutico , Trióxido de Arsênio/farmacologia , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Antineoplásicos/uso terapêutico , Antineoplásicos/farmacologia , Arsenicais/uso terapêutico , Arsenicais/farmacologia , Óxidos/uso terapêutico , Óxidos/farmacologia , AnimaisRESUMO
All-trans retinoic acid (ATRA), the major active metabolite of all-trans retinol (vitamin A), is a key hormonal signaling molecule. In the adult organism, ATRA has a widespread influence on processes that are crucial to the growth and differentiation of cells and, in turn, the acquisition of mature cell functions. Therefore, there is considerable potential in the use of retinoids to treat diseases. ATRA binds to the retinoic acid receptors (RAR) which, as activated by ATRA, selectively regulate gene expression. There are three main RAR isoforms, RARα, RARß, and RARγ. They each have a distinct role, for example, RARα and RARγ regulate myeloid progenitor cell differentiation and hematopoietic stem cell maintenance, respectively. Hence, targeting an isoform is crucial to developing retinoid-based therapeutics. In principle, this is exemplified when ATRA is used to treat acute promyelocytic leukemia (PML) and target RARα within PML-RARα oncogenic fusion protein. ATRA with arsenic trioxide has provided a cure for the once highly fatal leukemia. Recent in vitro and in vivo studies of RARγ have revealed the potential use of agonists and antagonists to treat diseases as diverse as cancer, heterotopic ossification, psoriasis, and acne. During the final drug development there may be a need to design newer compounds with added modifications to improve solubility, pharmacokinetics, or potency. At the same time, it is important to retain isotype specificity and activity. Examination of the molecular interactions between RARγ agonists and the ligand binding domain of RARγ has revealed aspects to ligand binding that are crucial to RARγ selectivity and compound activity and key to designing newer compounds.
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Receptores do Ácido Retinoico , Receptor gama de Ácido Retinoico , Humanos , Receptores do Ácido Retinoico/metabolismo , Receptores do Ácido Retinoico/agonistas , Animais , Tretinoína/farmacologia , Ligação Proteica , Leucemia Promielocítica Aguda/tratamento farmacológico , Leucemia Promielocítica Aguda/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/químicaRESUMO
The promyelocytic leukemia-retinoic acid receptor-α (PML::RARA) fusion is the hallmark of acute promyelocytic leukemia (APL) and is observed in over 95% of APL cases. RARA and homologous receptors RARB and RARG are occasionally fused to other gene partners, which differentially affect sensitivity to targeted therapies. Most APLs without RARA fusions have rearrangements involving RARG or RARB, both of which frequently show resistance to all-trans-retinoic acid (ATRA) and/or multiagent chemotherapy for acute myeloid leukemia (AML). We present a 13-year-old male diagnosed with variant APL with a novel FNDC3B::RARB in-frame fusion that showed no response to ATRA but responded well to conventional AML therapy. While FNDC3B has been identified as a rare RARA translocation partner in ATRA-sensitive variant APL, it has never been reported as a fusion partner with RARB and it is only the second known fusion partner with RARB in variant APL. We also show that this novel fusion confers an RNA expression signature that is similar to APL, despite clinical resistance to ATRA monotherapy.
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Leucemia Mieloide Aguda , Leucemia Promielocítica Aguda , Masculino , Humanos , Adolescente , Leucemia Promielocítica Aguda/tratamento farmacológico , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/metabolismo , Translocação Genética , Tretinoína/uso terapêutico , Leucemia Mieloide Aguda/genética , Receptor alfa de Ácido Retinoico/genética , Genômica , Proteínas de Fusão Oncogênica/genética , Fibronectinas/genéticaRESUMO
Although a growing body of evidence demonstrates that altered mtDNA content (mtDNAc) has clinical implications in several types of solid tumours, its prognostic relevance in acute promyelocytic leukaemia (APL) patients remains largely unknown. Here, we show that patients with higher-than-normal mtDNAc had better outcomes regardless of tumour burden. These results were more evident in patients with low-risk of relapse. The multivariate Cox proportional hazard model demonstrated that high mtDNAc was independently associated with a decreased cumulative incidence of relapse. Altogether, our data highlights the possible role of mitochondrial metabolism in APL patients treated with ATRA.
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Leucemia Promielocítica Aguda , Humanos , Leucemia Promielocítica Aguda/tratamento farmacológico , Leucemia Promielocítica Aguda/genética , Tretinoína/uso terapêutico , DNA Mitocondrial/genética , Relevância Clínica , Recidiva Local de Neoplasia/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Resultado do TratamentoRESUMO
BACKGROUND: Sorafenib resistance greatly reduces the efficacy of treatments in advanced hepatocellular carcinoma (HCC) patients, but the underlying mechanisms are not thoroughly understood. All-trans retinoic acid (ATRA), an anti-leukaemia agent, has attracted considerable attention due to its role in sensitizing cells to other anticancer treatments. We aimed to investigate the combined effect of ATRA and Sorafenib on HCC and the underlying mechanisms. METHODS: CCK-8, cell sphere formation, trans-well migration, and wound-healing assays were used to analyse the biological behaviours of HCC cells in vitro. Western blotting and qRT-PCR analysis were conducted to measure the expression of p21 activated kinase 1 (PAK1) and phospho-p21 activated kinase 1 (pPAK1). Xenograft models were established to confirm the synergistic effects of ATRA and Sorafenib in vivo. TUNEL assays and immunohistochemistry were utilized to determine apoptosis, proliferation, PAK1 and pPAK1 levels in tumour tissues. RESULTS: We observed that PAK1 was overexpressed in HCC, and its expression was negatively correlated with the survival of patients. PAK1 promoted the proliferation, self-renewal and epithelial-mesenchymal transition of HCC cells. Correlation analysis indicated that the IC50 of Sorafenib was positively correlated with the level of pPAK1 in HCC cell lines. ATRA inhibited the progression of HCC and sensitized HCC response to Sorafenib by downregulation of PAK1, as shown by the calculated coefficient of drug interaction and the data obtained from xenograft models. CONCLUSIONS: Our findings indicated that instead of treatment with Sorafenib alone, the combination of ATRA and Sorafenib provides a more effective treatment for HCC patients. Video Abstract.
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Antineoplásicos , Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Sorafenibe/farmacologia , Carcinoma Hepatocelular/patologia , Quinases Ativadas por p21/metabolismo , Regulação para Baixo , Neoplasias Hepáticas/patologia , Linhagem Celular Tumoral , Tretinoína/farmacologia , Apoptose , Proliferação de Células , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Resistencia a Medicamentos AntineoplásicosRESUMO
BACKGROUND: Single-target inhibitors have not been successful in cancer treatment due to the development of drug resistance. Nevertheless, therapeutic agents capable of simultaneously inhibiting multiple targets have revealed encouraging results in inducing apoptosis and overcoming drug resistance in cancerous cells. Here, we designed a composite liposomal nano-carrier co-loading 5-Fluorouracil (5-FU) with all-trans retinoic acid (ATRA) to assess anticancer efficacy of the combined drugs in colorectal cancer (CRC). METHODS: A PEGylated liposomal nano-carrier with phospholipid/cholesterol/DSPE-PEG (2000) was synthesized by the thin film hydration technique for co-delivery of ATRA and 5-FU. After characterizing, the role of 5-FU and ATRA co-loaded liposomal nano-carrier in proliferation, epithelial-mesenchymal transition (EMT), apoptosis, and cancer stem cells (CSCs) were investigated by using colony forming and MTT assay, RT-qPCR and Annexin V/PI kit. RESULTS: The average size of liposomes (LPs) was < 150 nm with uniform size distribution. Drug release analyses indicated that both ATRA and 5-FU could simultaneously release from LPs in a sustained release manner. The synergistic inhibitory effects of ATRA and 5-FU loaded in LPs were verified with a combination index of 0.43. Dual drug LPs showed the highest cytotoxicity, enhanced inhibition of cell proliferation, increased apoptotic potential, decreased CSCs, and attenuated EMT-associated biomarkers. Also, dual drug LPs decreased ß-catenin gene expression more than other liposomal formulations. CONCLUSION: These findings suggest that using LPs to achieve a synergistic effect of ATRA and 5-FU is an effectual approach to increase the therapeutic effect of 5-FU toward CRC cells.
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Neoplasias Colorretais , Fluoruracila , Humanos , Fluoruracila/farmacologia , Fluoruracila/uso terapêutico , Lipossomos , Lipopolissacarídeos , Tretinoína/farmacologia , Polietilenoglicóis , Neoplasias Colorretais/tratamento farmacológico , Linhagem Celular TumoralRESUMO
BACKGROUND: Holothuria (Halodeima) atra Jaeger, 1833 is a tropical sea cucumber usually harvested for the "bêche-de-mer" trade market. It has been reported to reproduce both sexually, through gamete spawning, or asexually, through fission. To date, no study has ever investigated clonality, nor genetic connectivity, among its populations, using microsatellite markers. METHODS AND RESULTS: We isolated the first 21 microsatellite loci specific for H. atra, which were then used to investigate clonal diversity, genetic structure and diversity among 44 H. atra individuals sampled in Reunion Island (southwestern Indian Ocean), over two seasons. All 21 loci were polymorphic, with number of alleles per locus ranging from 2 to 10. No repetitive multi-locus genotype (MLG) and few clonal lineages (MLL) were found. Observed heterozygosities per locus and season ranged from 0.000 to 0.909, while expected heterozygosities ranged from 0.290 to 0.882. Four loci were at Hardy-Weinberg equilibrium for both seasons, all others presenting a deficit of heterozygotes in one or both seasons. Meanwhile, no genetic differentiation was detected between seasons, according to assignment tests and global FST. CONCLUSIONS: These results suggest low asexual propagation in this population. These loci represent useful tools to better understand reproductive strategies and population connectivity of H. atra, and thus provide relevant knowledge for efficient management.
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Holothuria , Pepinos-do-Mar , Animais , Humanos , Equinodermos/genética , Holothuria/genética , Oceano Índico , Repetições de Microssatélites/genética , Polimorfismo Genético , Reunião , Pepinos-do-Mar/genética , Reprodução Assexuada/genética , Reprodução/genéticaRESUMO
AtrA belongs to the TetR family and has been well characterized for its roles in antibiotic biosynthesis regulation. Here, we identified an AtrA homolog (AtrA-lin) in Streptomyces lincolnensis. Disruption of atrA-lin resulted in reduced lincomycin production, whereas the complement restored the lincomycin production level to that of the wild-type. In addition, atrA-lin disruption did not affect cell growth and morphological differentiation. Furthermore, atrA-lin disruption hindered the transcription of regulatory gene lmbU, structural genes lmbA and lmbW inside the lincomycin biosynthesis gene cluster, and 2 other regulatory genes, adpA and bldA. Completement of atrA-lin restored the transcription of these genes to varying degrees. Notably, we found that AtrA-lin directly binds to the promoter region of lmbU. Collectively, AtrA-lin positively modulated lincomycin production via both pathway-specific and global regulators. This study offers further insights into the functional diversity of AtrA homologs and the mechanism of lincomycin biosynthesis regulation.
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Lincomicina , Streptomyces , Lincomicina/farmacologia , Lincomicina/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Streptomyces/genética , Streptomyces/metabolismo , Regulação Bacteriana da Expressão Gênica , Antibacterianos/metabolismoRESUMO
Resistance of tumor cells to retinoic acid (RA), a promising therapeutic agent, is the major factor limiting the use of RA in clinical practice. The mechanisms of resistance to RA are still poorly understood. Cellular Retinoic Acid Binding Proteins, CRABP1 and CRABP2, are essential mediators of RA signaling, but role of the two CRABP homologs in regulating cellular sensitivity to RA has not been well studied. In addition, the effects of CRABP1 and CRABP2 on cell proliferation have not been compared. Here, using a broad panel of breast cancer cell lines with different levels of RA sensitivity/resistance, we show for the first time that in the RA-sensitive cells, CRABP1 expression is restricted by methylation, and protein levels are highly variable. In the moderately-RA-resistant cell lines, high level of CRABP1 is observed both at the mRNA and protein levels, unchanged by inhibition of DNA methylation. The cell lines with maximum resistance to RA are characterized by complete repression of CRABP1 expression realized at transcriptional and posttranscriptional levels, and exogenous expression of each of the CRABP homologs has no effect on the studied characteristics. CRABP1 and CRABP2 proteins have opposing effects on proliferation and sensitivity to RA. In particular, CRABP1 stimulates and CRABP2 reduces proliferation and resistance to RA in the initially RA-sensitive cells, while in the more resistant cells the role of each homolog in both of these parameters is reversed. Overall, we have shown for the first time that CRABP proteins exert different effects on the growth and sensitivity to RA of breast cancer cells (stimulation, suppression, or no effect) depending on the baseline level of RA-sensitivity, with the effects of CRABP1 and CRABP2 homologs on the studied properties always being opposite.
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Neoplasias da Mama , Tretinoína , Humanos , Feminino , Tretinoína/farmacologia , Receptores do Ácido Retinoico/genética , Proliferação de Células , Linhagem Celular , ProteínasRESUMO
Cryptosporidium is an important intestinal zoonotic pathogen that can infect various hosts and cause diarrheal disease. There are no reports on the prevalence and molecular characterization of Cryptosporidium in wild birds in Cyprus. Therefore, the present study aimed to determine the prevalence of Cryptosporidium spp. and genotypes in wild birds found at Phassouri Reedbeds (Akrotiri Wetlands), Cyprus. Fecal samples of 75 wild birds (Eurasian coot Fulica atra, N = 48; Eurasian teal Anas crecca, N = 20; duck - Anas spp., Ν = 7) were screened for Cryptosporidium by PCR amplification and sequencing. Only one sample (1.3%) belonging to a Eurasian coot was PCR-positive for Cryptosporidium. Based on sequencing of the 18S rRNA locus, this species was identified as Cryptosporidium proventriculi. This is the first report on the molecular identification of this Cryptosporidium species in a Eurasian coot.
Assuntos
Criptosporidiose , Cryptosporidium , Animais , Cryptosporidium/genética , Criptosporidiose/epidemiologia , Chipre/epidemiologia , Aves , Animais Selvagens , Patos , Fezes , Genótipo , PrevalênciaRESUMO
Adjuvant endocrine therapy (AET) is the treatment of choice for early-stage estrogen receptor alpha (ERα)-positive breast cancer (BC). However, almost 40% of tamoxifen-treated cases display no response or a partial response to AET, thus increasing the need for new treatment options and strong predictors of the therapeutic response of patients at high risk of relapse. In addition to ERα, BC research has focused on ERß1 and ERß2 (isoforms of ERß), the second ER isotype. At present, the impact of ERß isoforms on ERα-positive BC prognosis and treatment remains elusive. In the present study, we established clones of MCF7 cells constitutively expressing human ERß1 or ERß2 and investigated their role in the response of MCF7 cells to antiestrogens [4-hydroxytamoxifen (OHΤ) and fulvestrant (ICI182,780)] and retinoids [all-trans retinoic acid (ATRA)]. We show that, compared to MCF7 cells, MCF7-ERß1 and MCF7-ERß2 cells were sensitized and desensitized, respectively, to the antiproliferative effect of the antiestrogens, ATRA and their combination and to the cytocidal effect of the combination of OHT and ATRA. Analysis of the global transcriptional changes upon OHT-ATRA combinatorial treatment revealed uniquely regulated genes associated with anticancer effects in MCF7-ERß1 cells and cancer-promoting effects in MCF7-ERß2 cells. Our data are favorable to ERß1 being a marker of responsiveness and ERß2 being a marker of resistance of MCF7 cells to antiestrogens alone and in combination with ATRA.