SKP1 promotes YAP-mediated colorectal cancer stemness via suppressing RASSF1

Abstract

Background: Cancer stem cells have been recognized as an important drug target, however, the mechanisms underlying the maintenance of cancer stem cells have not been fully understood. SKP1 is a traditional drug target for cancer therapy, while, whether SKP1 could be a target for eradicating cancer stem cells remains elusive.Methods: Human colorectal cancer cell lines HCT-116 and HT-29 and primary human colorectal cancer cells were used in this study. Gene manipulation was performed by lentivirus system. The mRNA and protein levels were examined by qRT-PCR and western blot, respectively. Sphere formation and transwell assay were employed for examination of sphere-forming and migration capacities. The tumorigenicity was examined by xenograft model. The transcriptional activities of the promoters were examined by luciferase reporter assay. Co-immunoprecipitation assay was used to test protein-protein interaction. The relationship between gene expression and survival was analyzed by Kaplan-meier analysis. The correlation between two genes was analyzed by Spearman analysis. Data are represented as mean ± s.d. and the significance was determined by Student’s t-test.Results: SKP1 is upregulated in colorectal cancer stem cells and predicts poor prognosis of colon cancer patients. Overexpression of SKP1 promotes the sphere-forming and migration capacities of colorectal cancer stem cells, and upregulates the expression of cancer stem cell markers. In contrast, SKP1 depletion produces the opposite effects. SKP1 strengthens YAP activity and knockdown of YAP abolished the effect of SKP1 on the stemness of colorectal cancer cells. SKP1 suppresses RASSF1 at both mRNA and protein levels and overexpression of RASSF1 abolished the effect of SKP1.Conclusion: In summary, our results demonstrated that SKP1 suppresses RASSF1 at both mRNA and protein level, attenuates Hippo signaling, activates YAP, and thereby promoting the stemness of colorectal cancer stem cells. Our works thus revealed a novel underlying mechanism of colorectal cancer stem cell maintenance and suggested a novel drug target for eradicating colorectal cancer stem cells.

METTL3 Facilitates Colorectal Carcinoma Progression via Regulating m6A-CRB3-Hippo Axis

“…The depletion of CRB3 could regulate hippo pathway and lead to increased nuclear localization of YAP/TAZ [30,31,42]. The hippo pathway plays a crucial role in regulating the CRC progression [43][44][45][46]. In present study, we found that CRB3 knockdown inhibited Hippo pathway, and increased nuclear localization of YAP, suggesting that CRB3 regulated the CRC progression by Hippo pathway.…”