Fig. 5. rhPRG4 enhances sorafenib and regorafenib effectiveness in inhibiting cell proliferation, preferentially in high CD44-expressing HCC cells.

Cells were analyzed by flow cytometry to quantify CD44 expression (histograms), and tested for growth rate for 72 hours in the presence or absence of sorafenib, regorafenib at a fixed concentration (2.5 µM), and increasing rhPRG4 concentrations (0–100 µg/ml). Drug effectiveness (% of drug-induced cell growth inhibition) is calculated for each rhPRG4 concentration as the percentage of cell growth inhibition induced by combined drug + PRG4 with reference to control (rhPRG4 alone). Data are expressed as the means ± SD of triplicates. T test (unpaired, two-tailed): *p < 0.05; **p < 0.01; ***p < 0.001.