IL-13/IL-13RA2 signaling promotes colorectal cancer stem cell tumorigenesis by inducing ubiquitinated degradation of p53

Cancer stem cells(CSCs)are considered tumor-initiating cells and the main drivers of disease progression.Targeting these rare cancer cells,however,remains challenging with respect to therapeutic benefit.Here,we report the up-regulation of IL-13RA2 expression in colorectal cancer(CRC)tissues and spheroid cells.The expression of IL-13RA2 was positively correlated with canonical stemness markers in CRC.We further demonstrated that the level of IL-13 was up-regulated in the serum of CRC patients.Biologically,recombinant IL-13(rIL13)stimulation promoted the sphere formation,proliferation,and migration of CRC cells in vitro and enhanced tumorigenesis in vivo.This phenotype could be reversed by knocking down IL-13RA2.Mechanistically,IL-13 activated autophagy by inducing LC3I/LC3II transformation in CRC-CSCs,which was crucial for the biological functions of IL-13.We further demonstrated that IL-13RA2 acted as a modular link of the E3 ligase UBE3C and the substrate p53 protein,enhancing the interaction of UBE3C and p53,thereby inducing the K48-linked ubiquitination of p53.In conclusion,the IL-13/IL-13RA2 signaling cascade promotes CRC-CSC self-renewal and tumorigenesis by inducing p53 ubiquitination,adding an important layer to the connection between IL-13 and p53,which can be translated into novel targeted therapies.

Targeting p85β nuclear translocation for the tumors with PIK3CA helical domain mutations

Phosphatidylinositol 3-kinases(PI3Ks)play key roles in tumorigenesis.PIK3CA,which encodes PI3K complex catalytic subunit p110a,is one of the most frequently mutated oncogenes in human cancers.1 So,targeting p110a holds great promise for cancer therapy.