Pingge Tian,Lei Xu,Fan Zou,Qian Jia,Yangjian Liu,Jin Chen,Pengzhen Wang
Background: Hypertrophic cardiomyopathy (HCM) is a common inherited heart disease characterized by left ventricular hypertrophy and excessive myocardial contraction. Endothelial cells (ECs) play a key role in the pathogenesis of HCM, and their secreted growth factors regulate the growth and function of cardiomyocytes. However, the specific molecular mechanisms and biomarkers associated with endothelial dysfunction in HCM remain unclear. Methods: Single-cell RNA sequencing (scRNA-seq) data were downloaded from the Gene Expression Omnibus (GEO) database (GSE255296), and bulk RNA sequencing data were obtained from GSE249925 and GSE180313. The scRNA-seq data were processed using the Seurat package for cell type annotation and batch effect removal. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was performed, and pathway activity was evaluated using the AUCell algorithm. SCENIC was applied to construct transcription factor-specific regulatory networks. Differential gene expression analysis was conducted using the limma package, and key genes were determined by intersecting differentially expressed genes (DEGs) with EC-specific highly expressed genes. The diagnostic efficacy of these key genes was assessed via receiver operating characteristic (ROC) curve analysis. The mRNA expression of genes in HUVECs treated with or without angiotensin II (Ang II) was assessed using qPCR. Cell viability was determined using the CCK-8 assay, and cell invasive ability was evaluated through Transwell assays to investigate the regulatory effect of TMTC1 overexpression on Ang II-induced injury in HUVECs. Results: Seven major cell types were identified, with cardiomyocytes and ECs being the main cell populations in HCM. KEGG enrichment analysis revealed significant activation of pathways such as the transforming growth factor-beta (TGF-β) signaling pathway in ECs. High-activity transcription factors NFIB, MECOM, and FLI1 were identified in ECs, whose target genes were enriched in processes related to cell morphogenesis. Three key genes-TMTC1, RPS6KA2, and F8-were selected based on differential expression and EC specificity. These genes were lowly expressed in HCM and exhibited high diagnostic efficacy, with area under the curve (AUC) values > 0.7. Ultimately, the CCK-8 assay results indicated that Ang II inhibited the viability of HUVECs, and this inhibitory effect could be reversed by the overexpression of TMTC1 (oe-TMTC1). Furthermore, Transwell assays indicated that Ang II impaired cellular migration, and this impairment could be restored by oe-TMTC1. Conclusion: The identified key genes and pathways provide new targets for therapeutic intervention and contribute to a deeper understanding of the pathogenesis of HCM.
Jianfa Wu,Huang Chen,Sihong Wang,Lei Peng,Xiaoying Hu,Zhou Liu
Objectives Ribosomal protein S6 kinase A2 (RPS6KA2) has been identified as a potential prognostic biomarker in several cancers, including breast cancer, glioblastoma, and prostate cancer. However, its functional significance in ovarian cancer is not well characterized. This study was designed to explore the therapeutic relevance of modulating RPS6KA2 in the context of ovarian cancer, particularly in relation to cisplatin resistance. Methods The expression levels of RPS6KA2 and key regulators involved in autophagy and ferroptosis were assessed using quantitative reverse transcription-PCR, immunofluorescence staining, immunohistochemistry, and western blotting. Prognostic associations were conducted using the Kaplan-Meier Plotter database. Autophagy flux assays and visualization of autophagosomes were performed to assess autophagy activity. Ferroptosis-related parameters, including intracellular iron content, glutathione (GSH) levels, reactive oxygen species (ROS) generation, and mitochondrial membrane potential, were measured to determine ferroptotic changes. In vivo experiments were carried out to determine the antitumor efficacy of RPS6KA2 modulation in combination with pathway-specific agents. Results Using ovarian cancer cell lines and clinical tissue samples, we demonstrated that RPS6KA2 expression was significantly downregulated in cisplatin-resistant cells and tissues compared to their sensitive counterparts. Low RPS6KA2 expression correlated with unfavorable patient outcomes and enhanced chemoresistance. Mechanistically, RPS6KA2 inhibited autophagy by modulating the phosphatidylinositol 3-kinase-protein kinase B-mammalian target of rapamycin (PI3K-AKT-mTOR) signaling pathway, which in turn increased sensitivity to cisplatin. Additionally, RPS6KA2 facilitated ferroptosis, contributing to its tumor-suppressive function. miR-512-3p was identified as a negative regulator of RPS6KA2, driving cisplatin resistance through suppression of RPS6KA2 expression. In vivo validation confirmed that combining RPS6KA2 targeting with autophagy inhibitors or ferroptosis inducers significantly enhanced cisplatin sensitivity in ovarian cancer models. Conclusion These results collectively indicate that targeting the miR-512-3p/RPS6KA2 regulatory axis may offer a novel and effective strategy for overcoming cisplatin resistance in ovarian cancer.
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