Biology subjects

Ramaswamy, G.

Publications and source records attributed to Ramaswamy, G..

3 recordsLinked to original sources

bioRxiv2026

Targeting AATF reprograms the tumor microenvironment and suppresses hepatocellular carcinoma via MIR100HG TGFβ signaling

Hepatocellular carcinoma (HCC), a leading cause of cancer death, has a dynamic and heterogeneous tumor microenvironment (TME) that drives progression and therapeutic resistance. We previously elucidated that apoptosis antagonizing transcription factor (AATF) drives angiogenesis in HCC. However, its role in TME remains unexplored. We employed an orthotopic xenograft mouse model, implanting human HCC cells into the liver, and achieved liver-specific silencing via tail vein injection of AAV8 carrying mouse-specific siAATF or siControl. Histological, biochemical, and molecular analyses, combined with whole-genome transcriptomics mapped to mouse and human genomes, were used to study TME and tumor compartments separately. Silencing of AATF in the TME significantly reduced tumor growth compared with controls. Furthermore, AATF loss disrupted key processes in TME, including inflammation, immune response, angiogenesis, and extracellular matrix remodeling. Mechanistically, TGF-{beta} signaling was significantly suppressed in the TME, thereby affecting tumor cell cycle and metabolic activity, ultimately leading to tumor regression. The long noncoding RNA (lncRNA) analysis identified MIR100HG as a key downstream regulator of AATF in the TGF-{beta} signaling pathway. These findings expand the oncogenic role of AATF to include regulation of the TME via the AATF-MIR100HG-TGF-{beta} axis, highlighting its potential as a therapeutic target in HCC.

cancer biology↗

bioRxiv2025

Promoter DNA Methylation Epigenetically Regulates the Tumor-Suppressor Function of the miR-379/656 (C14MC) Cluster in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality. Several microRNAs (miRNAs) play key roles in HCC development and progression. The role of epigenetic processes like DNA methylation in the regulation of miRNAs is critical to HCC pathogenesis. In this study, we show that the miR-379/656 cluster (C14MC) acts as a tumor suppressor cluster and is epigenetically regulated by DNA methylation. We demonstrated that C14MC is downregulated in HCC cell lines through nCounter assay and in clinical samples from The Cancer Genome Atlas (TCGA) liver hepatocellular carcinoma tissues. The C14MC promoter was identified and characterized through cloning and dual luciferase assay. Furthermore, we demonstrated that the loss of C14MC tumor suppressor function is directly regulated by the hypermethylation of promoter-bound CpGs, as shown in artificial methylation experiments. The reactivation of specific C14MC miRNAs, like miR-299-5p and miR-376c-3p via mimics, abrogated the expression of several target oncogenes, including PARP1, SPP1, RAD21, and CENPA that regulate critical molecular pathways such as the p53 signaling and NF-kappa B signaling pathways in HCC. Additionally, overexpression of miR-299-5p and miR-376c-3p inhibited HCC cell migration and invasion, suggesting that overexpression of candidate C14MC miRNAs can mitigate cancer hallmarks in HCC cells. Furthermore, we checked for the clinical correlation of C14MC targets and their target genes in terms of survival outcomes and identified the key genes associated with prognostic potential in HCC. We conclude from our experimental findings that C14MC is a tumor-suppressor miRNA cluster and is regulated epigenetically by methylation in HCC. Several of these miRNAs and their targets can be used for early HCC diagnosis and prognosis. Thus, targeting C14MC can be useful in HCC management.

cancer biology↗

bioRxiv2024

Silencing of Hepatic AATF Ameliorates Metabolic Dysfunction Associated Steatohepatitis by Promoting Fatty Acid β-Oxidation in Experimental models

Background & aimsMetabolic dysfunction-associated steatohepatitis (MASH) is a multifactorial disease driven by complex molecular mechanisms. Identifying key regulators is critical for developing targeted therapies. Here, we demonstrate the impact of the loss of apoptosis antagonizing transcription factor (AATF) on hepatic lipid metabolism and MASH progression. MethodsA preclinical mouse model recapitulating human MASH was established by feeding C57Bl/6 mice either a chow diet (CD) or a western diet with sugar water (WD). Hepatic AATF silencing was achieved by tail vein injection of siAATF delivered by adeno-associated virus 8 (AAV8) with the liver-specific thyroxine-binding globulin (TBG) promoter. In addition to histological, biochemical, and molecular biology evaluations, the mechanistic insights were derived from whole transcriptomics and untargeted metabolomics analyses. ResultsAAV8-mediated specific knockdown of AATF in hepatocytes significantly reduced body weight, liver weight, and insulin resistance in mice fed with western diet (WD). However, no such effects were observed in mice fed with a chow diet (CD). Further analyses showed reduced liver injury, steatosis, and steatohepatitis in WDsiAATF mice. Transcriptomic analysis demonstrated that loss of AATF alleviated cellular stress, inflammation, and fibrosis in WD-fed mice. Moreover, AATF silencing led to alterations in lipid metabolism, notably by decreasing hepatic lipogenesis in the WD mice. Interestingly, untargeted metabolomics revealed an increase in the biosynthesis of glycerophospholipids and beta-oxidation of fatty acids in WDsiAATF mice. ConclusionOur findings reveal a previously unrecognized role of AATF as a central regulator of hepatic lipid metabolism in MASH, acting through the AKT-mTORC1 signaling pathway, and establish its inhibition as a promising therapeutic strategy for metabolic liver disease.

molecular biology↗