STK26 Promotes the Stabilization of ATF6 to Facilitate the Progression of Colorectal Cancer.

STK26 is highly expressed in colorectal cancer (CRC) and linked to tumorigenesis. Although implicated in unfolded protein response (UPR)-related oxidative stress, whether STK26 regulates CRC occurrence via the ATF6 pathway-a classic UPR branch governing proteostasis and cell survival-remains unestablished. In our research, we found that STK26 expression aberrantly upregulated in CRC is closely associated with poor prognosis. In vitro, tumor phenotype assays showed that STK26 drives CRC cell growth, proliferation, and migration. These effects were reversed by the ATF6 inhibitor Ceapin-A7, demonstrating that STK26's oncogenic function depends on ATF6. Moreover, transcriptome sequencing revealed that STK26 is associated with the protein folding, sorting, and degradation pathway, and a luciferase reporter assay showed that STK26 activated the ATF6 signal pathway. Furthermore STK26 interacted with p50ATF6 and enhanced its protein stabilization. In vivo studies demonstrated that the administration of the STK26 inhibitor Hesperadin significantly suppressed CRC growth, suggesting a tumor-promoting role for STK26 in CRC pathogenesis. In summary, our research reveals that STK26 is a novel regulator that promotes the growth, proliferation, and migration of CRC cells by activating the ATF6 signaling pathway and stabilizing p50ATF6. Hence, the STK26-ATF6 axis has the potential to become a new target for treating colorectal cancer.