Effect of PHRF1 in radiosensitivity of hepatocellular carcinoma through CARHSP1/TNF-α signaling pathway: an in vitro study

BACKGROUND This study investigated the expression pattern of plant homeodomain and ring finger domains 1 (PHRF1) in hepatocellular carcinoma (HCC), its effects on malignant phenotypes and radiosensitivity, and the potential involvement of the calcium regulated heat stable protein 1 (CARHSP1)/tumor necrosis factor alpha (TNF-α) pathway. METHODS The Cancer Genome Atlas liver HCC cohort was analyzed with Gene Expression Profiling Interactive Analysis 2. HepG2 cells were transfected to overexpress PHRF1, with or without CARHSP1 rescue. Quantitative real-time polymerase chain reaction, western blotting, cell counting kit-8, flow cytometry, Transwell invasion, and colony formation assays were used to assess molecular expression, proliferation, apoptosis, invasion, and response to 4 Gy X-ray irradiation. RESULTS PHRF1 and TNF expression were lower and CARHSP1 expression was higher in HCC than in normal liver tissue (p = 0.022). Overall survival differed between the high- and low-PHRF1 expression groups (p = 0.018). PHRF1 overexpression reduced proliferation and invasion and increased apoptosis. In the plotted data, apoptosis increased from approximately 6% to 14% and invasive cells decreased from approximately 140 to 95. PHRF1 overexpression reduced CARHSP1 and TNF-α expression, whereas CARHSP1 rescue partially reversed these effects. After 4 Gy irradiation, colony number decreased from approximately 80 to 50 and apoptosis increased from approximately 13% to 30% in PHRF1-overexpressing cells compared with irradiated vector controls (p<0.001). CONCLUSIONS These findings suggest that PHRF1 may enhance the radiosensitivity of HepG2 cells, potentially through suppression of CARHSP1/TNF-α signaling. Further validation in additional HCC models and multi-dose irradiation studies is required.