title: 3,3'-diindolylmethane enhances the efficacy of butyrate in colon cancer prevention through down-regulation of survivin.
abstract: Butyrate is an inhibitor of histone deacetylase (HDAC) and has been extensively evaluated as a chemoprevention agent for colon cancer. We recently showed that mutations in the adenomatous polyposis coli (APC) gene confer resistance to HDAC inhibitor-induced apoptosis in colon cancers. Here, we show that APC mutation rendered colon cancer cells resistant to butyrate-induced apoptosis due to the failure of butyrate to down-regulate survivin in these cells. Another cancer-preventive agent, 3,3'-diindolylmethane (DIM), was identified to be able to down-regulate survivin in colon cancers expressing mutant APC. DIM inhibited survivin mRNA expression and promoted survivin protein degradation through inhibition of p34(cdc2)-cyclin B1-mediated survivin Thr(34) phosphorylation. Pretreatment with DIM enhanced butyrate-induced apoptosis in colon cancer cells expressing mutant APC. DIM/butyrate combination treatment induced the expression of proapoptotic Bax and Bak proteins, triggered Bax dimerization/activation, and caused release of cytochrome c and Smac proteins from mitochondria. Whereas overexpression of survivin blocked DIM/butyrate-induced apoptosis, knocking down of survivin by small interfering RNA increased butyrate-induced apoptosis in colon cancer cells. We further showed that DIM was able to down-regulate survivin and enhance the effects of butyrate in apoptosis induction and prevention of familial adenomatous polyposis in APC(min/+) mice. Thus, the combination of DIM and butyrate is potentially an effective strategy for the prevention of colon cancer.
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, North Dakota State University, Fargo, North Dakota 58105, USA.
authors.forename: Namrata
authors.initials: N
authors.lastname: Bhatnagar
authors.forename: Xia
authors.initials: X
authors.lastname: Li
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.forename: Xudong
authors.initials: X
authors.lastname: Zhou
authors.forename: Scott H
authors.initials: SH
authors.lastname: Garrett
authors.forename: Bin
authors.initials: B
authors.lastname: Guo
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D011125:Adenomatous Polyposis Coli / Q000188:drug therapy / Q000473:pathology; D000818:Animals; D016588:Anticarcinogenic Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects; D002087:Butyrates / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D045744:Cell Line, Tumor / Q000187:drug effects / Q000378:metabolism; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D018076:DNA, Complementary / Q000235:genetics; D015536:Down-Regulation / Q000187:drug effects; D004357:Drug Synergism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D017491:Genes, APC; D056572:Histone Deacetylase Inhibitors; D006801:Humans; D007211:Indoles / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D051034:Inhibitor of Apoptosis Proteins; D051379:Mice; D008817:Mice, Mutant Strains; D008869:Microtubule-Associated Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000037:antagonists & inhibitors; D000077022:Survivin
chemical_list: D016588:Anticarcinogenic Agents; C107489:BIRC5 protein, human; D002087:Butyrates; D018076:DNA, Complementary; D056572:Histone Deacetylase Inhibitors; D007211:Indoles; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D011993:Recombinant Fusion Proteins; D000077022:Survivin; C016392:3,3'-diindolylmethane