International Journal of Molecular Sciences Review Wnt-Independent and Wnt-Dependent Effects of APC Loss on the Chemotherapeutic Response Casey D. Stefanski 1,2 and Jenifer R. Prosperi 1,2,3,* 1 Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46617, USA;
[email protected] 2 Mike and Josie Harper Cancer Research Institute, South Bend, IN 46617, USA 3 Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-South Bend, South Bend, IN 46617, USA * Correspondence:
[email protected]; Tel.: +1-574-631-4002 Received: 30 September 2020; Accepted: 20 October 2020; Published: 22 October 2020 Abstract: Resistance to chemotherapy occurs through mechanisms within the epithelial tumor cells or through interactions with components of the tumor microenvironment (TME). Chemoresistance and the development of recurrent tumors are two of the leading factors of cancer-related deaths. The Adenomatous Polyposis Coli (APC) tumor suppressor is lost in many different cancers, including colorectal, breast, and prostate cancer, and its loss correlates with a decreased overall survival in cancer patients. While APC is commonly known for its role as a negative regulator of the WNT pathway, APC has numerous binding partners and functional roles. Through APC’s interactions with DNA repair proteins, DNA replication proteins, tubulin, and other components, recent evidence has shown that APC regulates the chemotherapy response in cancer cells. In this review article, we provide an overview of some of the cellular processes in which APC participates and how they impact chemoresistance through both epithelial- and TME-derived mechanisms. Keywords: adenomatous polyposis coli; chemoresistance; WNT signaling 1.