Curcumin mediates polyamine metabolism and sensitizes gastrointestinal cancer cells to antitumor polyamine-targeted therapies.

Curcumin, a natural polyphenol that contributes to the flavor and yellow pigment of the spice turmeric, is known for its antioxidant, anti-inflammatory, and anticarcinogenic properties. Capable of affecting the initiation, promotion, and progression of carcinogenesis through multiple mechanisms, curcumin has potential utility for both chemoprevention and chemotherapy. Previous studies demonstrated that curcumin can inhibit ornithine decarboxylase (ODC) activity in human leukemia and breast cancer cells, and pretreatment with dietary curcumin blocks carcinogen-induced ODC activity in rodent models of skin, colon, and renal cancer. The current study investigated the regulation of polyamine metabolism in human gastric and colon carcinoma cell lines in response to curcumin. Curcumin treatment significantly induced spermine oxidase (SMOX) mRNA and activity, which results in the generation of hydrogen peroxide, a source of ROS. Simultaneously, curcumin down regulated spermidine/spermine N1-acetyltransferase (SSAT) activity and the biosynthetic enzymes ODC and S-adenosylmethionine decarboxylase (SAMDC), thereby diminishing intracellular polyamine pools. Combination treatments using curcumin with the ODC inhibitor 2-difluoromethylornithine (DFMO), an agent currently in clinical chemoprevention trials, significantly enhanced inhibition of ODC activity and decreased growth of GI cancer cell lines beyond that observed with either agent alone. Similarly, combining curcumin with the polyamine analogue bis(ethyl)norspermine enhanced growth inhibition that was accompanied by enhanced accumulation of the analogue and decreased intracellular polyamine levels beyond those observed with either agent alone. Importantly, cotreatment with curcumin permitted the lowering of the effective dose of ODC inhibitor or polyamine analogue. These studies provide insight into the polyamine-related mechanisms involved in the cancer cell response to curcumin and its potential as a chemopreventive or chemotherapeutic agent in the GI tract.

Efficacy and Safety of Curcumin in Treatment of Intestinal Adenomas in Patients With Familial Adenomatous Polyposis.

BACKGROUND & AIMS: Familial adenomatous polyposis is an autosomal dominant disorder characterized by the development of hundreds of colorectal adenomas and eventually colorectal cancer. Oral administration of the spice curcumin has been followed by regression of polyps in patients with this disorder. We performed a double-blinded randomized trial to determine the safety and efficacy of curcumin in patients with familial adenomatous polyposis. METHODS: This study included 44 patients with familial adenomatous polyposis (18-85 years old) who had not undergone colectomy or had undergone colectomy with ileorectal anastomosis or ileal anal pouches, had at least 5 intestinal adenomatous polyps, and had enrolled in Puerto Rico or the United States from September 2011 through November 2016. Patients were randomly assigned (1:1) to groups given 100% pure curcumin (1,500 mg orally, twice per day) or identical-appearing placebo capsules for 12 months. The number and size of lower gastrointestinal tract polyps were evaluated every 4 months for 1 year. The primary outcome was the number of polyps in the curcumin and placebo groups at 12 months or at the time of withdrawal from the study according to the intention-to-treat principle. RESULTS: After 1 year of treatment, the average rate of compliance was 83% in the curcumin group and 91% in the placebo group. After 12 weeks, there was no significant difference in the mean number of polyps between the placebo group (18.6; 95% CI, 9.3-27.8) and the curcumin group (22.6; 95% CI, 12.1-33.1; P = .58). We found no significant difference in mean polyp size between the curcumin group (2.3 mm; 95% CI, 1.8-2.8) and the placebo group (2.1 mm; 95% CI, 1.5-2.7; P = .76). Adverse events were few, with no significant differences between groups. CONCLUSIONS: In a double-blinded randomized trial of patients with familial adenomatous polyposis, we found no difference in the mean number or size of lower intestinal tract adenomas between patients given curcumin 3,000 mg/day and those given placebo for 12 weeks. Clinicaltrials.gov ID NCT00641147.

Chemoprevention in familial adenomatous polyposis.

Familial adenomatous polyposis (FAP) predictably leads to adenomas and eventual adenocarcinomas in the lower gastrointestinal tract and less frequently, the upper gastrointestinal tract. Chemopreventive strategies have been studied in FAP patients to delay the development of adenomas in the upper and lower gastrointestinal tract, as well as to prevent recurrence of adenomas in the retained rectum of patients after prophylactic surgery with colectomy and ileorectal anastamosis (IRA). The nonsteroidal anti-inflammatory drug (NSAID) sulindac and selective cyclooxygenase-2 (COX-2) inhibitor celecoxib reduce polyposis of the retained rectum after colectomy with IRA. Reports of cardiovascular risks of some NSAIDs and selective COX-2 inhibitors have led to promising studies of lower doses in combination with ursodeoxycholic acid, statin, and difluoromethylornithine. Curcumin and eicosapentaenoic acid show efficacy in small clinical trials of FAP chemoprevention. This article will review the concept of chemoprevention and the current clinical literature in FAP chemoprevention.

Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology.

In the United States, colorectal cancer (CRC) is the third most common cancer diagnosed among men and women and the second leading cause of death from cancer. CRC largely can be prevented by the detection and removal of adenomatous polyps, and survival is significantly better when CRC is diagnosed while still localized. In 2006 to 2007, the American Cancer Society, the US Multi Society Task Force on Colorectal Cancer, and the American College of Radiology came together to develop consensus guidelines for the detection of adenomatous polyps and CRC in asymptomatic average-risk adults. In this update of each organization's guidelines, screening tests are grouped into those that primarily detect cancer early and those that can detect cancer early and also can detect adenomatous polyps, thus providing a greater potential for prevention through polypectomy. When possible, clinicians should make patients aware of the full range of screening options, but at a minimum they should be prepared to offer patients a choice between a screening test that is effective at both early cancer detection and cancer prevention through the detection and removal of polyps and a screening test that primarily is effective at early cancer detection. It is the strong opinion of these 3 organizations that colon cancer prevention should be the primary goal of screening.

Combination treatment with curcumin and quercetin of adenomas in familial adenomatous polyposis.

BACKGROUND & AIMS: Familialadenomatous polyposis (FAP) is an autosomal-dominant disorder characterized by the development of hundreds of colorectal adenomas and eventual colorectal cancer. Regression of adenomas in this syndrome occurs with the administration of nonsteroidal anti-inflammatory drugs and cyclooxygenase-2 inhibitors, but these compounds can have considerable side effects. We evaluated the efficacy of the combination of diet-derived nonprescription supplements curcumin and quercetin to regress adenomas in patients with FAP. METHODS: Five FAP patients with prior colectomy (4 with retained rectum and 1 with an ileal anal pouch) received curcumin 480 mg and quercetin 20 mg orally 3 times a day. The number and size of polyps were assessed at baseline and after therapy. The Wilcoxon signed-rank test was used to determine differences in the number and size of polyps. Treatment side effects and medication compliance also were evaluated. RESULTS: All 5 patients had a decreased polyp number and size from baseline after a mean of 6 months of treatment with curcumin and quercetin. The mean percent decrease in the number and size of polyps from baseline was 60.4% (P < .05) and 50.9% (P < .05), respectively. Minimal adverse side effects and no laboratory abnormalities were noted. CONCLUSIONS: The combination of curcumin and quercetin appears to reduce the number and size of ileal and rectal adenomas in patients with FAP without appreciable toxicity. Randomized controlled trials are needed to validate these findings.

Loss of imprinting of insulin growth factor II gene: a potential heritable biomarker for colon neoplasia predisposition.

BACKGROUND & AIMS: Loss of genomic imprinting (LOI) of insulin-like growth factor II gene (IGF2) involves abnormal activation of the normally silent maternally inherited allele. LOI of IGF2 has been associated with personal and family history of colorectal neoplasia (CRN), supporting a role for LOI in colorectal carcinogenesis. Whether LOI of IGF2 is associated with known environmental risk factors for CRN is unknown. METHODS: We performed quantitative hot-stop PCR for imprinting analysis of IGF2 on normal peripheral blood lymphocytes (PBL) of individuals. Environmental exposures including tobacco, alcohol, NSAIDs, and nutrient consumption (calcium, folate, selenium, fiber, and fat) were correlated with LOI expression in PBL. Odds ratios (OR) and 95% CI were calculated. RESULTS: The prevalence of LOI of IGF2 was examined in 172 individuals. Persons with CRN (adenomas/cancer) had 5.1-fold (95% CI: 1.92-13.6) increased risk of having LOI of IGF2 in PBL compared with those without CRN. In contrast, tobacco smoking (OR = 0.96, 95% CI: 0.36-2.55), alcohol consumption (OR = 1.22, 95% CI: 0.45-3.3), and NSAIDs use (OR = 1.21, 95% CI: 0.38-3.94) were not significantly associated with LOI of IGF2. Nutrient ingestion including calcium (P = 0.61), folate (P = 0.23), selenium (P = 0.19), fiber (P = 0.63), and fat (P = 0.14) was not statistically correlated with LOI of IGF2. CONCLUSIONS: Abnormal imprinting of IGF2 gene was strongly associated with CRN but not with any of the environmental exposures examined. LOI of IGF2 does not appear to be an environmentally acquired phenomenon but rather a hereditary risk factor for CRN.