APOA1 and hepatocellular carcinoma: By functionalizing the surface of apoA-I-rHDL with pH-sensitive cell-penetrating peptides, Ding et al. (2015) demonstrated enhanced SR-BI-mediated uptake of the hydrophobic apoptosis inducer gambogic acid within the cytosol of HCC cells at a pH of 6.4 versus a normal physiological pH of 7.4.