title: 5-Fluorouracil mediated anti-cancer activity in colon cancer cells is through the induction of Adenomatous Polyposis Coli: Implication of the long-patch base excision repair pathway.
abstract: Colorectal cancer (CRC) patients with APC mutations do not benefit from 5-FU therapy. It was reported that APC physically interacts with POLβ and FEN1, thus blocking LP-BER via APC's DNA repair inhibitory (DRI) domain in vitro. The aim of this study was to elucidate how APC status affects BER and the response of CRC to 5-FU. HCT-116, HT-29, and LOVO cells varying in APC status were treated with 5-FU to evaluate expression, repair, and survival responses. HCT-116 expresses wild-type APC; HT-29 expresses an APC mutant that contains DRI domain; LOVO expresses an APC mutant lacking DRI domain. 5-FU increased the expression of APC and decreased the expression of FEN1 in HCT-116 and HT-29 cells, which were sensitized to 5-FU when compared to LOVO cells. Knockdown of APC in HCT-116 rendered cells resistant to 5-FU, and FEN1 levels remained unchanged. Re-expression of full-length APC in LOVO cells caused sensitivity to 5-FU, and decreased expression of FEN1. These knockdown and addback studies confirmed that the DRI domain is necessary for the APC-mediated reduction in LP-BER and 5-FU. Modelling studies showed that 5-FU can interact with the DRI domain of APC via hydrogen bonding and hydrophobic interactions. 5-FU resistance in CRC occurs with mutations in APC that disrupt or eliminate the DRI domain's interaction with LP-BER. Understanding the type of APC mutation should better predict 5-FU resistance in CRC than simply characterizing APC status as wild-type or mutant.
authors.affiliation: KIIT School of Biotechnology, KIIT University, Campus-11, Patia, Bhubaneswar, Orissa 751024, India.
authors.forename: Dipon
authors.initials: D
authors.lastname: Das
authors.affiliation: KIIT School of Biotechnology, KIIT University, Campus-11, Patia, Bhubaneswar, Orissa 751024, India.
authors.forename: Ranjan
authors.initials: R
authors.lastname: Preet
authors.affiliation: KIIT School of Biotechnology, KIIT University, Campus-11, Patia, Bhubaneswar, Orissa 751024, India.
authors.forename: Purusottam
authors.initials: P
authors.lastname: Mohapatra
authors.affiliation: KIIT School of Biotechnology, KIIT University, Campus-11, Patia, Bhubaneswar, Orissa 751024, India.
authors.forename: Shakti Ranjan
authors.initials: SR
authors.lastname: Satapathy
authors.affiliation: KIIT School of Biotechnology, KIIT University, Campus-11, Patia, Bhubaneswar, Orissa 751024, India.
authors.forename: Sumit
authors.initials: S
authors.lastname: Siddharth
authors.affiliation: Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC, USA.
authors.forename: Tigist
authors.initials: T
authors.lastname: Tamir
authors.affiliation: Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, Mohali, Punjab 160062, India.
authors.forename: Vaibhav
authors.initials: V
authors.lastname: Jain
authors.affiliation: Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, Mohali, Punjab 160062, India.
authors.forename: Prasad V
authors.initials: PV
authors.lastname: Bharatam
authors.affiliation: Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC, USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Wyatt
authors.affiliation: KIIT School of Biotechnology, KIIT University, Campus-11, Patia, Bhubaneswar, Orissa 751024, India. Electronic address: cnkundu@gmail.com.
authors.forename: Chanakya Nath
authors.initials: CN
authors.lastname: Kundu
mesh_terms: D025601:Adenomatous Polyposis Coli Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D045744:Cell Line, Tumor / Q000187:drug effects; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000235:genetics; D004260:DNA Repair / Q000187:drug effects*; D045585:Flap Endonucleases / Q000378:metabolism; D005472:Fluorouracil / Q000494:pharmacology*; D055785:Gene Knockdown Techniques; D045325:HCT116 Cells / Q000187:drug effects; D006801:Humans; D006860:Hydrogen Bonding; D062105:Molecular Docking Simulation; D008969:Molecular Sequence Data; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D017434:Protein Structure, Tertiary
chemical_list: C555337:APC protein, human; D025601:Adenomatous Polyposis Coli Protein; D000964:Antimetabolites, Antineoplastic; D045585:Flap Endonucleases; C468317:FEN1 protein, human; D046988:Proteasome Endopeptidase Complex; D005472:Fluorouracil