STOML2 interacts with PHB to activate the MEK/ERK signaling pathway and mediates autophagy‑related proteins in the progression of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) treatment remains challenging due to the prevalence of metastasis and chemotherapy resistance. Mitochondrial stomatin‑like protein 2 (STOML2), which is upregulated in various solid tumors, is associated with a poor prognosis; however, its biological function and molecular mechanism in HCC remain unclear. The present study aimed to elucidate the oncogenic mechanism of STOML2 in HCC and to explore its potential as a therapeutic target. Firstly, STOML2 expression in HCC and matched normal liver tissues was analyzed. In addition, STOML2‑knockdown (HCCLM3‑short hairpin RNA‑STOML2) and ‑overexpression (Huh7‑STOML2) cell models were established. Wound healing, Cell Counting Kit‑8 and Transwell assays, and flow cytometry were performed to assess cell proliferation, invasion, migration and apoptosis <i>in vitro</i>. Furthermore, the biological function of STOML2 was confirmed in vivo. Co‑immunoprecipitation (co‑IP) and immunofluorescence staining were conducted to validate the interaction of STOML2 with prohibitin (PHB) following the prediction of binding partners. Downstream pathways regulated by STOML2 were identified using western blotting and were further investigated using the RAF1 inhibitor sorafenib. The present study revealed that STOML2 expression was significantly upregulated in HCC tissues and metastatic lesions, and was associated with poor patient prognosis. The <i>in vitro</i> experiments showed that STOML2 overexpression promoted proliferation, invasion, migration and autophagy, while inhibiting apoptosis in Huh7 cells. Conversely, STOML2 knockdown reversed these phenotypic changes. Furthermore, co‑IP confirmed the direct interaction between STOML2 and PHB, which activated the RAF/MEK/ERK signaling pathway. The <i>in vivo</i> experiments further confirmed that STOML2 overexpression significantly accelerated tumor growth, whereas STOML2 or PHB knockdown inhibited tumor progression. In addition, sorafenib treatment suppressed STOML2‑mediated cell migration and the expression of autophagy‑related proteins by blocking the MAPK pathway. These findings elucidated the molecular mechanism by which STOML2 promotes the malignant progression of HCC and demonstrated that targeted inhibition of the PHB‑MAPK pathway may reverse the pro‑tumorigenic effects of STOML2. STOML2 may serve as both a prognostic biomarker and a therapeutic target in HCC. The current study provides a theoretical foundation for individualized treatment in patients with HCC and high STOML2 expression.