The exploration of drugs derived from natural sources holds significant promise in addressing current limitations in ovarian cancer (OC) treatments. While previous studies have highlighted the remarkable anti-cancer properties of the natural compound β-sitosterol (SIT) across various tumors, its specific role in OC treatment remains unexplored. This study aims to investigate the anti-tumor activity of SIT in OC using in vitro and in vivo models, delineate potential mechanisms, and establish a preclinical theoretical foundation for future clinical trials, thus fostering further research. Utilizing network pharmacology, we pinpoint SIT as a promising candidate for OC treatment and predict its potential targets and pathways. Through a series of in vitro and in vivo experiments, we unveil a novel mechanism through which SIT mitigates the malignant biological behaviors of OC cells by modulating redox status. Specifically, SIT selectively targets argininosuccinate synthetase 1 (ASS1), a protein markedly overexpressed in OC tissues and cells. Inhibiting ASS1, SIT enhances the interaction between Nrf2 and Keap1, instigating the ubiquitin-dependent degradation of Nrf2, subsequently diminishing the transcriptional activation of downstream antioxidant genes HO-1 and NQO1. The interruption of the antioxidant program by SIT results in the substantial accumulation of reactive oxygen species (ROS) in OC cells. This, in turn, upregulates PTEN, exerting negative regulation on the phosphorylation activation of AKT. The suppression of AKT signaling disrupted downstream pathways associated with cell cycle, cell survival, apoptosis, migration, and invasion, ultimately culminating in the death of OC cells. Our research uncovers new targets and mechanisms of SIT against OC, contributing to the existing knowledge on the anti-tumor effects of natural products in the context of OC. Additionally, this research unveils a novel role of ASS1 in regulating the Nrf2-mediated antioxidant program and governing redox homeostasis in OC, providing a deeper understanding of this complex disease.
Gonadal trans-differentiation from ovary to testis occurs in a same individual, suggesting a role of epigenetic regulation.However, histone modifications concerning the sex reversal process remain elusive.We analyzed histone modifications using liquid chromatography-tandem mass spectrometry (LC-MS/MS).Chromatin immunoprecipitation followed by sequencing (ChIP-seq) technology was used to test chromatin immunoprecipitation of gonads.Western blot analysis was performed to analyze protein expression.Immunofluorescence analysis was conducted to localize proteins in gonadal tissues.Here, we report a developmental atlas of histone modifications in the gonadal differentiation, including acetylation, methylation, and ubiquitination.We provided a detail distribution map of these modification sites including novel histone modifications along histones H2a, H2b, H3, and H4, and revealed their relationship with types of gonadal differentiation.We then determined a testis-enriched histone modification site, H2b monoubiquitination at K120, and its association with spermatogenesis.ChIP-seq demonstrated that the modification was highly enriched in the male sex-determining gene dmrt1 (doublesex and mab-3 related transcription factor 1), in particular, in its exon regions, suggesting its role in transcriptional regulation of dmrt1 in testis.Together, these data not only provide a new resource for epigenetic study in gonadal development, but also define an association of histone modifications with gonadal differentiation from ovary to testis.
The placenta and tumors can exhibit a shared expression profile of proto-oncogenes. The basis of placenta-derived heat shock protein gp96, which induces prophylactic and therapeutic T cell responses against cancer including hepatocellular carcinoma (HCC), remains unknown. Here, we identified the associated long peptides from human placental gp96 using matrix-assisted laser desorption/ionization-time-of-flight and mass spectrometry and analyzed the achieved proteins through disease enrichment analysis. We found that placental gp96 binds to numerous peptides derived from 73 proteins that could be enriched in multiple cancer types. Epitope-harboring peptides from glypican 3 (GPC3) and paternally expressed gene 10 (PEG10) were the major antigens mediating anti-HCC T cell immunity. Molecular docking analysis showed that the GPC3- and PEG10-derived peptides, mainly obtained from the cytotrophoblast layer of the mature placenta, bind to the lumenal channel and client-bound domain of the gp96 dimer. Immunization with bone marrow-derived dendritic cells pulsed with recombinant gp96-GPC3 or recombinant gp96-PEG10 peptide complex induced specific T cell responses, and T cell transfusion led to pronounced growth inhibition of HCC tumors in nude mice. We demonstrated that the chaperone gp96 can capture antigenic peptides as an efficient approach for defining tumor rejection oncoantigens in the placenta and provide a basis for developing GPC3 and PEG10 peptide-based vaccines against HCC. This study provides insight into the underlying mechanism of the antitumor response mediated by embryonic antigens from fetal tissues, and this will incite more studies to identify potential tumor rejection antigens from placenta.
MicroRNA-140-5p plays pivotal role in different types of human malignancies, while its involvement in osteosarcoma is unknown. Our study aimed to investigate the functionality of microRNA-140-5p in osteosarcoma. Plasma levels of microRNA-140-5p and glucose transporter 1 (GLUT-1) in both osteosarcoma and healthy controls were measured by qRT-PCR and ELISA, respectively. Correlation between plasma levels of microRNA-140-5p and GLUT-1 was analyzed by Pearson correlation coefficient. Correlation between plasma levels of microRNA-140-5p and clinical data of patients with osteosarcoma was analyzed by Chi-square test. MicroRNA-140-5p mimic and GLUT-1 expression vector were transfected into cells of human osteosarcoma cell lines, and the effects on microRNA-140-5p expression, GLUT-1 expression and cell proliferation were analyzed by qRT-PCR, Western-blot and CCK-8 assay, respectively. Plasma levels of microRNA-140-5p were significantly lower and plasma levels of GLUT-1 were significantly higher in osteosarcoma patients than that in healthy controls. Levels of plasma microRNA-140-5p and GLUT-1 were reversely correlated in osteosarcoma patients. Plasma levels of microRNA-140-5p were correlated with tumor size but not with other clinical data of patients. MicroRNA-140-5p mimic significantly inhibited cancer cell proliferation, while GLUT-1 overexpression significantly promoted cancer cell proliferation. MicroRNA-140-5p mimic significantly downregulated GLUT-1 expression. GLUT-1 overexpression showed no significant effect on microRNA-140-5p expression but attenuated the inhibitory effects of microRNA-140-5p mimic on cell proliferation. We therefore conclude that microRNA-140-5p is downregulated in osteosarcoma and overexpression of microRNA-140-5p may inhibit cancer cell proliferation by downregulating GLUT-1.
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