MOTS-c relieves hepatocellular carcinoma resistance to TRAIL-induced apoptosis under hypoxic conditions by activating MEF2A.

Experimental cell research2025PMID: 39581216

View on PubMed DOI: 10.1016/j.yexcr.2024.114354

Animal StudyMOTS-C

Plain Language Summary

In vitro study using Huh7 and HCCLM3 hepatocellular carcinoma cells and clinical serum samples demonstrating that MOTS-c levels are reduced in HCC patients and that MOTS-c reverses cancer cell resistance to TRAIL-induced apoptosis under hypoxic conditions through MEF2A (myocyte enhancer factor 2A) activation, restoring pro-apoptotic signaling in the hypoxic tumor microenvironment. Identifies a novel HCC anti-tumor mechanism for MOTS-c. Establishes MOTS-c as a potential sensitizer for TRAIL-based HCC therapy—where tumor hypoxia-driven resistance to apoptosis is a major treatment challenge, and MOTS-c's MEF2A-dependent restoration of apoptotic sensitivity could enhance existing anti-cancer strategies.

Abstract

BACKGROUND: Mitochondrial ORF of the 12S rRNA type-c (MOTS-c) as an AMPK agonist can regulate the expression of adaptive nuclear genes to promote cell homeostasis. However, the investigation of MOTS-c in hepatocellular carcinoma (HCC) is insufficient. This study aims to reveal the role of MOTS-c on HCC cell apoptosis. METHODS: Huh7 and HCCLM3 cells were incubated with MOTS-c under a hypoxic condition. MOTS-c levels were quantified by enzyme-linked immunosorbent assay in the peripheral blood of HCC patients and healthy controls. Cell viability was detected by 3-(4,5-Dimethylthazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell apoptosis was investigated by flow cytometry and Tunel assay. Protein expression was detected by western blotting or immunohistochemistry assay. Dual-luciferase reporter assay and chromatin immunoprecipitation assay were performed to identify the association among myocyte enhancer factor 2A (MEF2A), death receptor 4 (DR4) and DR5. A tumor-bearing nude mouse model was conducted to assess the effect of MOTS-c on HCC tumor formation in vivo. RESULTS: MOTS-c levels in the peripheral blood of HCC patients were significantly lower compared to healthy individuals. MOTS-c promoted HCC cell apoptosis under hypoxia conditions. Hypoxia stimulation decreased the protein expression of MEF2A, DR4, DR5, fas-associating via death domain (FADD) and caspase-8, while these effects were attenuated after MOTS-c treatment. MOTS-c induced TRAIL-induced apoptosis of HCC cells by activating MEF2A through the phosphorylation of AMPK under hypoxia treatment. In addition, MEF2A transcriptionally up-regulated DR4 and DR5. MOTS-c activated MEF2A to regulate DR4 and DR5 expression, further mediating TRAIL-induced apoptosis. Further, MOTS-c treatment relieved hypoxia-induced tumor growth in vivo. CONCLUSION: MOTS-c relieved hypoxia-induced HCC cell resistance to TRAIL-caused apoptosis by activating MEF2A.

Authors

Shen, Haiying; Nie, Junjie; Wang, Xiaojun; Li, Guangqing; Zhao, Liwei; Jin, Yuji; Jin, Lianhai

Keywords

AMPKHCCMEF2AMOTS-CTRAIL-Induced apoptosishypoxia