Panoply™ Human CFTR Over-expressing Stable Cell Line

The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-activated chloride (Cl⁻) channel widely expressed in the epithelial cells of various tissues and organs. Growing evidence indicates that aberrant CFTR expression or mutation is closely linked to the initiation and progression of cancer. Malignant glioma is the most common and aggressive type of intracranial tumor, yet the role of CFTR in its pathogenesis remains unclear. Here, researchers found that CFTR is expressed in malignant glioma cell lines. Inhibiting CFTR channel function or knocking down CFTR expression reduced glioma cell viability, whereas CFTR overexpression enhanced it. Furthermore, in both subcutaneous and orthotopic xenograft models, CFTR overexpression inhibited apoptosis and promoted glioma progression. Mechanistic studies revealed that CFTR activates the Akt/Bcl2 signaling pathway; inhibition of the PI3K/Akt pathway (using MK-2206 or LY294002) abolished the upregulation of Bcl2 and the enhanced cell viability induced by CFTR overexpression. Notably, CFTR protein expression levels were significantly elevated in samples from glioblastoma patients. Collectively, these findings elucidate the mechanism by which CFTR promotes glioma progression through the upregulation of the Akt/Bcl2-mediated anti-apoptotic pathway, suggesting that CFTR is a promising therapeutic target for glioma.

Here, the researchers evaluated whether CFTR influences apoptosis. Flow cytometry results showed that CFTR overexpression inhibited basal levels of apoptosis (Figure 1A). Furthermore, CFTR overexpression significantly attenuated H2O2-induced apoptosis in U87 cells. Specifically, upon H2O2 treatment, over 60% of control U87 cells were Annexin V-positive (indicating apoptosis), whereas only approximately 40% of CFTR-overexpressing U87 cells underwent apoptosis (Figure 1A). Consistent with these findings, the expression levels of cleaved caspase-3 and cleaved PARP were downregulated in CFTR-overexpressing U87 cells compared to the control group following H2O2 treatment (Figure 1B). These results indicate that CFTR-overexpressing glioma cells exhibit a survival advantage. To preliminarily identify genes potentially contributing to the enhanced viability of CFTR-overexpressing U87 cells, the researchers utilized a real-time quantitative PCR array (PAHS-020C) containing 84 genes related to cell proliferation and apoptosis. As shown in Figure 1C, the expression of several apoptosis-related genes-including Atm, Bax, Bcl2, Birc5, Ddx11, Dnm2, Rad51, Rb1, and Rbl2-was upregulated in CFTR-overexpressing U87 cells, with Bcl2 showing the most significant upregulation. To validate this finding, they examined Bcl2 protein expression levels in U87 and SW1088 cells subjected to CFTR modulation. The results demonstrated that CFTR overexpression enhanced Bcl2 expression in U87 cells, whereas CFTR knockdown reduced Bcl2 expression in SW1088 cells (Figure 1D). These results indicate that CFTR regulates the response of glioma cells to apoptotic signals via a Bcl2-mediated anti-apoptotic pathway.

Figure 1. Cystic fibrosis transmembrane conductance regulator (CFTR) regulates apoptotic response in glioma cell lines. (Zhao M, et al., 2020)