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Dietary polyamine intake and risk of colorectal adenomatous polyps.

ABSTRACT: Putrescine, spermidine, and spermine are the polyamines required for human cell growth. The inhibition of ornithine decarboxylase (ODC), which is the rate-limiting enzyme of polyamine biosynthesis, decreases tumor growth and the development of colorectal adenomas. A database was developed to estimate dietary polyamine exposure and relate exposure to health outcomes.We hypothesized that high polyamine intake would increase risk of colorectal adenoma and that the allelic variation at ODC G>A +316 would modify the association.Polyamine exposure was estimated in subjects pooled (n = 1164) from the control arms of 2 randomized trials for colorectal adenoma prevention [Wheat Bran Fiber low-fiber diet arm (n = 585) and Ursodeoxycholic Acid placebo arm (n = 579)] by using baseline food-frequency questionnaire data. All subjects had to have a diagnosis of colorectal adenoma to be eligible for the trial.A dietary intake of polyamines above the median amount in the study population was associated with 39% increased risk of colorectal adenoma at follow-up (adjusted OR: 1.39; 95% CI: 1.06, 1.83) in the pooled sample. In addition, younger participants (OR: 1.94; 95% CI: 1.23, 3.08), women (OR: 2.43; 95% CI: 1.48, 4.00), and ODC GG genotype carriers (OR: 1.59; 95% CI: 1.00, 2.53) had significantly increased odds of colorectal adenoma if they consumed above-median polyamine amounts.This study showed a role for dietary polyamines in colorectal adenoma risk. Corroboration of these findings would confirm a previously unrecognized, modifiable dietary risk factor for colorectal adenoma.

SUBMITTER: Vargas AJ

PROVIDER: S-EPMC3374737 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature

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Dietary polyamine intake and risk of colorectal adenomatous polyps.

Vargas Ashley J AJ Wertheim Betsy C BC Gerner Eugene W EW Thomson Cynthia A CA Rock Cheryl L CL Thompson Patricia A PA

The American journal of clinical nutrition 20120530 1

<h4>Background</h4>Putrescine, spermidine, and spermine are the polyamines required for human cell growth. The inhibition of ornithine decarboxylase (ODC), which is the rate-limiting enzyme of polyamine biosynthesis, decreases tumor growth and the development of colorectal adenomas. A database was developed to estimate dietary polyamine exposure and relate exposure to health outcomes.<h4>Objective</h4>We hypothesized that high polyamine intake would increase risk of colorectal adenoma and that t ...[more]

PMID: 22648715

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Project description:Colorectal tumors mostly arise from sporadic adenomatous polyps. Polyps are defined as a mass of cells that protrudes into the lumen of the colon. Adenomatous polyps are benign neoplasms that, by definition display some characteristics of dysplasia. It has been shown that polyps were benign tumors which may undergo malignant transformation. Adenomatous polyps have been classified into three histologic types; tubular, tubulovillous, and villous with increasing malignant potential. The ability to differentially diagnose these colorectal adenomatous polyps is important for therapeutic intervention. To date, little efforts have been directed to identifying genetic changes involved in adenomatous polyps. This study was designed to examine the relevance of mitochondrial genome alterations in the three adenomatous polyps. Using high resolution restriction endonucleases and PCR-based sequencing, fifty-seven primary fresh frozen tissues of adenomatous polyps (37 tumors and 20 matched surrounding normal tissues) obtained from the southern regional Cooperative Human Tissue Network (CHTN) and Grady Memorial Hospital at Atlanta were screened with three mtDNA regional primer pairs that spanned 5.9 kbp. Results from our data analyses revealed the presence of forty-four variants in some of these mitochondrial genes that the primers spanned; COX I, II, III, ATP 6, 8, CYT b, ND 5, 6 and tRNAs. Based on the MITODAT database as a sequence reference, 25 of the 44 (57%) variants observed were unreported. Notably, a heteroplasmic variant C8515G/T in the MT-ATP 8 gene and a germline variant 8327delA in the tRNAlys was observed in all the tissue samples of the three adenomatous polyps in comparison to the referenced database sequence. A germline variant G9055A in the MT-ATP 6 gene had a frequency of 100% (17/17) in tubular and 57% (13/23) in villous adenomas; no corresponding variant was in tubulovillous adenomas. Furthermore, A9006G variant at MT-ATP 6 gene was observed at frequency of 57% (13/23) in villous adenomas only. Interestingly, variants A9006G and G9055A were absent in the villous tissue samples that were clinicopathological designated as "polyvillous adenomas". Our current data provide a basis for continued investigation of certain mtDNA variants as predictors of the three adenomatous polyps in a larger number of clinicopathological specimens.

Project description:BackgroundEnergy metabolism in carcinogenesis is poorly understood. It is widely accepted the majority of colorectal cancers (CRCs) arise from adenomatous polyps (APs). We aimed to characterize the bioenergetic alterations in APs and CRCs.MethodsFifty-six APs, 93 CRCs and adjacent normal mucosae were tested. Oxygen consumption rate (OCR) was measured representing mitochondrial oxidative phosphorylation (OxPhos), and extracellular acidification rate (ECAR)was measured representing glycolysis. Mitochondrial DNA (mtDNA) variants and mutations were studied. Over-expressed metabolic genes in APs were identified by microarray and validated by qRT-PCR, Western blots and immunohistochemistry. Identified genes were knocked down in WiDr and colo205 CRC cell lines, and their expression was analyzed in APs/CRCs with enhanced glycolysis.FindingsECAR, not OCR, was significantly increased in APs. While no difference of ECAR was found between CRCs and normal mucosae, OCR was significantly reduced in CRCs. OCR/ECAR ratio was decreased in APs over 1 cm, APs with a villous component and CRCs, indicating their glycolytic tendencies. The number of mtDNA mutations was increased in APs and CRCs, but not correlated with metabolic profiles. Two metabolic genes ALDOB and SLC16A4 were up-regulated in APs. Both ALDOB-knockdown and SLC16A4-knockdown CRC cell lines showed increased basal motichondrial OxPhos and decreased basal glycolysis. Moreover, the increase of mitochondrial ATP-linked respiration and the decrease of glycolytic capacity were showed in SLC16A4-knockdown cells. Finally, APs/CRCs with enhanced glycolysis had increased SLC16A4 expression.InterpretationATP production shifts from OxPhos to glycolysis in the process of AP enlargement and villous transformation. OxPhos defects are present in CRCs but not in APs. APs and CRCs tend to accumulate mtDNA mutations, but these are not correlated with bioenergetic profiles. Finally, the ALDOB and SLC16A4 may contribute to the glycolytic shift in APs/CRCs.

Dataset Information

Dietary polyamine intake and risk of colorectal adenomatous polyps.

Publications

Dietary polyamine intake and risk of colorectal adenomatous polyps.

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