PDEδ inhibition impedes the proliferation and survival of human colorectal cancer cell lines harboring oncogenic KRas

Novelty and ImpactThe ‘undruggable’ KRas is a prevalent oncogene in CRC with poor prognosis. In hPDAC cells pharmacological targeting of PDEδ affects oncogenic KRas signaling, but it remained unclear whether this approach is transferable to other cancer cells. Here, we show that genetic and pharmacologic PDEδ inhibition also impedes the proliferation of oncogenic, but not wild-type KRas bearing CRC cells indicating that PDEδ inhibition is a specific tool for targeting growth of oncogenic KRas bearing CRC.AbstractRas proteins, most notably KRas, are prevalent oncogenes in human cancer. Plasma membrane localization and thereby signaling of KRas is regulated by the prenyl-binding protein PDEδ. Recently, we have reported the specific anti-proliferative effects of PDEδ inhibition in KRas-dependent human pancreatic ductal adenocarcinoma cell lines. Here, we investigated the proliferative dependence on the solubilizing activity of PDEδ of human colorectal cancer (CRC) cell lines with or without oncogenic KRas mutations. Our results show that genetic and pharmacologic interference with PDEδ specifically inhibits proliferation and survival of CRC cell lines harboring oncogenic KRas mutations whereas isogenic cell lines in which the KRas oncogene has been removed, or cell lines with oncogenic BRaf mutations or EGFR overexpression are not dependent on PDEδ. Pharmacological PDEδ inhibition is therefore a possible new avenue to target oncogenic KRas bearing CRC.