xav939 and Adenomatous-Polyposis-Coli

Colorectal Cancer (CRC) is highly heterogeneous for which prognosis is dependent mainly on clinical staging. There is a need to stratify subpopulations of CRC on molecular basis to better predict outcome and therapy response. Truncating mutations in adenomatous polyposis coli (APC) are well-described events in CRC carcinogenesis. Clinical and genotypic characterization of Middle Eastern CRC based on presence and type of APC was determined in 412 CRC tumors using modern next generation sequencing. APC truncating mutations were identified in 58.2% (240/412) of CRCs. Overall, mutation was significant predictor of superior overall survival. Further, the type of APC mutations (short or long) did not have impact on clinical outcome. However, in vitro analysis showed difference between CRC cell lines carrying short truncating APC vs CRC cells that carry long truncating APC mutation in response to 5-flourouracil (5-FU). Importantly, we were able to overcome the resistance to 5-FU seen in CRC cells carrying short APC by tankyrase inhibitor, XAV939, thereby inhibiting Wnt/β-catenin signaling cascade. Overall, our results showed that APC mutation status plays an important role in predicting overall survival in Middle Eastern population. Furthermore, in vitro data showed that selective targeting of APC mutated CRC by tankyrase inhibitor can be an effective strategy to overcome 5-FU resistance in CRC cells.

Topics: Adenomatous Polyposis Coli; Aged; Antimetabolites, Antineoplastic; Cell Line, Tumor; Colorectal Neoplasms; Drug Resistance, Neoplasm; Female; Fluorouracil; Heterocyclic Compounds, 3-Ring; Humans; Male; Middle Aged; Mutation; Saudi Arabia; Survival; Tankyrases; Wnt Signaling Pathway

With the goal of modeling human disease of the large intestine, we sought to develop an effective protocol for deriving colonic organoids (COs) from differentiated human embryonic stem cells (hESCs) or induced pluripotent stem cells (iPSCs). Extensive gene and immunohistochemical profiling confirmed that the derived COs represent colon rather than small intestine, containing stem cells, transit-amplifying cells, and the expected spectrum of differentiated cells, including goblet and endocrine cells. We applied this strategy to iPSCs derived from patients with familial adenomatous polyposis (FAP-iPSCs) harboring germline mutations in the WNT-signaling-pathway-regulator gene encoding APC, and we generated COs that exhibit enhanced WNT activity and increased epithelial cell proliferation, which we used as a platform for drug testing. Two potential compounds, XAV939 and rapamycin, decreased proliferation in FAP-COs, but also affected cell proliferation in wild-type COs, which thus limits their therapeutic application. By contrast, we found that geneticin, a ribosome-binding antibiotic with translational 'read-through' activity, efficiently targeted abnormal WNT activity and restored normal proliferation specifically in APC-mutant FAP-COs. These studies provide an efficient strategy for deriving human COs, which can be used in disease modeling and drug discovery for colorectal disease.

Topics: Adenoma; Adenomatous Polyposis Coli; Adenomatous Polyposis Coli Protein; Antibiotics, Antineoplastic; Blotting, Western; Cell Differentiation; Cell Proliferation; Colon; Colorectal Neoplasms; Drug Screening Assays, Antitumor; Enteroendocrine Cells; Flow Cytometry; Fluorescent Antibody Technique; Gene Expression Profiling; Gentamicins; Germ-Line Mutation; Goblet Cells; Heterocyclic Compounds, 3-Ring; Human Embryonic Stem Cells; Humans; Immunohistochemistry; Induced Pluripotent Stem Cells; Microscopy, Confocal; Mutation; Organoids; Real-Time Polymerase Chain Reaction; Sirolimus; Wnt Signaling Pathway