Aberrant activation of Wnt/β-catenin signaling plays an unequivocal role in colorectal cancer, but identification of effective Wnt inhibitors for use in cancer remains a tremendous challenge. New insights into the regulation of this pathway could reveal new therapeutic point of intervention, therefore are greatly needed. Here we report a novel FAK/PYK2/GSK3βY216/β-catenin regulation axis: FAK and PYK2, elevated in adenomas in APCmin/+ mice and in human colorectal cancer tissues, functioned redundantly to promote the Wnt/β-catenin pathway by phosphorylating GSK3βY216 to reinforce pathway output-β-catenin accumulation and intestinal tumorigenesis. We previously showed that Wnt-induced β-catenin accumulation requires Wntinduced GSK3β/β-TrCP interaction; the current study revealed that phosphorylation of GSK3βY216 was a molecular determinant of GSK3β recruitment of β-TrCP. Pharmacological inhibition of FAK/PYK2 suppressed adenoma formation in APCmin/+ mice accompanied with reduced intestinal levels of phospho-SK3βY216 and β-catenin, indicating that FAK/PYK2/GSK3βY216 axis is critical for the activation of Wnt/β-catenin signaling in APCdriven intestinal tumorigenesis.
Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All of the animals were handled according to approved institutional animal care and use committee (IACUC) protocols (#14013138) of the University of Pittsburgh.
- Jonathan A Cooper, Fred Hutchinson Cancer Research Center, United States
© 2015, Gao et al.
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