Panoply™ Human KCNN4 Over-expressing Stable Cell Line

The presence of liver cancer stem cells (LCSCs) is a contributing factor to treatment failure in hepatocellular carcinoma (HCC). Metabolic plasticity is a hallmark of LCSCs, relying on transporters and ion channels for the exchange of metabolites and ions. The K+ channel protein KCNN4 (Potassium Calcium-Activated Channel Subfamily N Member 4) has been reported to promote cell metabolism and malignant progression of HCCs, but its influence on LCSC stemness has remained unclear. In this study, researchers confirmed via RT-PCR and Western blot analysis that KCNN4 is highly expressed in LCSCs. Subsequently, by analyzing the proportion of the CD133+CD44+ LCSC subpopulation, assessing stemness-related transcription factors in vitro, and conducting sphere-formation assays-combined with in vivo orthotopic liver tumor formation and limiting dilution assays-the researchers demonstrated that KCNN4 promotes stemness in HCC cells. Furthermore, metabolic enzyme assays and Seahorse analysis revealed that KCNN4 enhances glucose metabolism in LCSCs; notably, the glycolysis inhibitor 2-DG or the oxidative phosphorylation (OXPHOS) inhibitor oligomycin abolished the KCNN4-induced increase in the LCSC population. Collectively, these findings indicate that KCNN4 promotes LCSC stemness by enhancing glucose metabolism, suggesting that KCNN4 is a promising molecular target for eliminating LCSCs in HCC.

In this study, the researchers generated KCNN4-overexpressing cell lines. As expected, KCNN4 overexpression led to a significant increase in the proportion of the CD133+CD44+ subpopulation, the expression levels of stemness-related transcription factors (SOX2, OCT4, and NANOG), and the number of spheres formed. Resistance to radiotherapy and chemotherapy is a hallmark of cancer stem cells (CSCs). Therefore, the researchers treated the cells with varying concentrations of sorafenib and gemcitabine for 48 hours and assessed cell growth and apoptosis. Overall, the survival rates of both KCNN4-overexpressing and KCNN4-knockdown cells decreased as drug concentrations increased (Figures 1A, B). However, at any given drug concentration, the survival rate was significantly higher in the KCNN4-overexpression group compared to the control (ctrl) and KCNN4-knockdown groups. Furthermore, the KCNN4-knockdown group exhibited a higher rate of apoptosis compared to control cells, whereas the KCNN4-overexpression group demonstrated enhanced drug resistance (Figure 1C). These results indicate that KCNN4 promotes stemness characteristics in liver cancer stem cells (LCSCs) in vitro, thereby highlighting the role of KCNN4 in driving tumor progression.

Figure 1. KCNN4 enhanced the chemotherapy resistance of HCC. (Fan J, et al., 2022)