Evaluating Combined Sorafenib and Gemcitabine Treatment in HepG2 Cells and a NOD/SCID Mouse Xenograft Model: A Pilot Study

Liver cancer remains a leading cause of cancer-related mortality due to drug resistance and limited treatment options. There is an urgent need to explore therapeutic strategies to improve outcomes. This pilot study presents a protocol for assessing the potential effects and underlying mechanisms of the combination of sorafenib and gemcitabine in liver cancer. The liver cancer cell line HepG2 was used, and a non-obese diabetic/severe combined immunodeficient (NOD/SCID) mouse xenograft model was established. Key procedural steps are demonstrated including: (1) HepG2 cell culture and drug treatment; (2) MTT assay setup, incubation, and absorbance reading; (3) protein extraction, SDS-PAGE, transfer, and immunoblotting for ERK and p-ERK; (4) subcutaneous xenograft establishment in NOD/SCID mice; (5) tumor measurement and volume calculation; and (6) VEGF immunohistochemistry on tumor sections. Critical steps, troubleshooting tips, and equipment specifications are provided. The combination of sorafenib (3 µmol/L) and gemcitabine (10 µmol/L) achieved an inhibition rate of 71.23% ± 6.76% at 72 h, with a q-value of 1.35, suggesting a synergistic effect at this specific dose pair under the conditions tested. Compared with the control group, the combination treatment was associated with reduced p-ERK expression, decreased tumor volume, and qualitatively lower VEGF immunostaining. These data show a correlative association between reduced p-ERK expression and the observed anti-proliferative effect, without establishing causality. In HepG2 cells and a NOD/SCID mouse xenograft model, the combination of sorafenib and gemcitabine shows preliminary evidence of anti-proliferative potential and is associated with reduced VEGF expression; however, this finding does not constitute direct evidence of anti-angiogenic activity, as microvessel density or functional vascular analyses were not performed. This reproducible protocol provides a useful framework for evaluating drug combinations in HCC models and can be adapted for other targeted therapy-chemotherapy regimens, though further mechanistic and dose-validation studies are required before any clinical implications can be drawn.