PTPN23 Overexpression Is Associated with Reduced Proliferation and Tumor Growth in Murine Models of Colorectal Cancer.

Protein tyrosine phosphatases (PTPs) are key regulators of intracellular signaling cascades involved in cell growth, proliferation, differentiation, inflammation, and cancer. PTPN23, a non-receptor PTP, is involved in endosomal sorting and thereby regulates the internalization of growth factor receptors, such as the epidermal growth factor receptor (EGFR). PTPN23 has been proposed to exert tumor-suppressive effects in several epithelial cancers, including breast and lung cancer. PTPN23 is ubiquitously expressed in the body; however, it is particularly highly expressed in the intestine, where it plays an essential role in maintaining intestinal homeostasis. Despite these observations, its involvement in colorectal carcinoma (CRC) remains largely unexplored. To investigate the function of PTPN23 in CRC, we generated PTPN23-overexpressing CRC cell lines and evaluated their effects in vitro and in subcutaneous tumor models. Our in-vitro findings demonstrate that PTPN23 overexpression resulted in reduced proliferation levels and follow-up experiments showed suppression of colorectal cancer growth and proliferation in experimental CRC models. These effects were accompanied by changes in EGFR-associated signaling; however, the underlying mechanism, including a potential role of EGFR trafficking, remains to be established through direct experimental validation. Together, these findings expand current knowledge of PTPN23 in colorectal cancer and provide a basis for future studies addressing its biological function and therapeutic relevance.