SLC15A1 and hepatocellular carcinoma: Stable cell lines with PEPT1 overexpression or knockdown were constructed in HCC cells with relatively low endogenous levels of PEPT1 (Bel7405 and HCCLM3) and relatively high endogenous levels of PEPT1 (Huh7 and PLC/PRF/5), respectively (Figure 1A).