Curcumin and Salsalate Suppresses Colonic Inflammation and Procarcinogenic Signaling in High-Fat-Fed, Azoxymethane-Treated Mice

High-fat diets (HFDs) and excess adiposity increase proinflammatory cytokines in the colon, altering gene expression in a manner that promotes the development of colorectal cancer (CRC). Thus, compounds that reduce this biochemical inflammation are potential chemopreventive agents. Curcumin (CUR), a dietary polyphenol, and salsalate (SAL), a non-steroidal anti-inflammatory drug, are both anti-inflammatories. We investigated the inhibitory effects of CUR with or without SAL on inflammatory cytokines and procarcinogenic signaling in azoxymethane (AOM)-treated A/J mice. A sub-tumorigenic AOM dose was chosen to produce a biochemical and molecular procarcinogenic colonic environment without tumors. Mice were fed either a HFD (60% of kilocalories) or low-fat diet (LFD) (10% of kilocalories). One HFD treatment group received 0.2% CUR in the diet; one received 0.2% CUR + 0.15% SAL; and one received 0.4% CUR + 0.3% SAL. The HFD mice developed 30% greater fat mass than the LFD mice (<i>p</i> < 0.05). The colonic concentrations of interleukin-1β (IL-1β) and interleukin-6 (IL-6) in the HFD mice were decreased by 50–69% by the high-dose combination regimen (<i>p</i> < 0.015). Only the combination regimens significantly suppressed phosphorylation of protein kinase B (Akt) and nuclear factor-κB (NF-κB) p65 (<i>p</i> < 0.044). The combination of CUR and SAL reduces the concentration of proinflammatory cytokines and diminishes activation of Akt and NF-κB more effectively than CUR alone, providing a scientific basis for examining whether this combination mitigates the risk of CRC in obese individuals

Body weight of Apc^1638N offspring of fathers fed diets differing in B vitamin content.

<p><b>A)</b> Body weight of DEF compared to CTRL offspring, by sex. <b>B)</b> Body weight of SUPP compared to CTRL offspring, by sex. Repeated-measures ANOVA for paternal diet effect p = 0.64 and 0.02 in males and female offspring respectively. Paternal diets: DEF, B-vitamin deficient; CTRL, B-vitamin replete; SUPP, B-vitamin supplemented.<b>*</b> denotes significant difference (in females) compared to CTRL (p ≤0.05) by t-test. n = 14–22 per group.</p

Overlap between differentially methylated genes in sperm and differentially expressed genes in offspring.

<p><b>A)</b> CTRL v DEF comparison. Common in sperm and female offspring: Smc4, Spon2, Gpd2, Aurka, Tspan8, Tbc1d10a, Lss, Abhd2, Fdps, Hsd17b7, Dsg1c. Common in sperm and male offspring: Lrrc16a. Common in sperm and female and male offspring: Apol9b. <b>B)</b> CTR v SUPP comparison. Common in sperm and female offspring: 1300002K09Rik, Cyp3a16, Ethe1, Igf2, 1810011O10Rik. Common in sperm and male offspring: Col27a1.</p

Top networks of differentially expressed genes between CTRL and SUPP offspring unique to females.

<p><b>A)</b>. Network associated with ‘Lipid Metabolism’, ‘Behavior’ and ‘Nervous System Development and Function’. Score = 36. <b>B)</b>. Network associated with ‘Glutathione Depletion in Liver’, ‘Drug Metabolism’ and ‘Protein Synthesis’. Score = 44. Red = up-regulated in SUPP, Green = down-regulated in SUPP. Unshaded genes are present in the biological network but were not significantly altered in our dataset. The network score is a negative log p value of the Fisher exact test, which is testing whether these genes are grouped by chance.</p

Effect of differential B vitamin intake on blood B vitamin concentration in fathers.

<p>Effect of differential B vitamin intake on blood B vitamin concentration in fathers.</p

Hepatic folate content of weanling wild-type and adult Apc^1638N offspring of fathers consuming different quantities of B vitamins.

<p>Hepatic folate content of weanling wild-type and adult Apc^1638N offspring of fathers consuming different quantities of B vitamins.</p

Design of animal experiment.

<p>Apc1638N (+/−), mice heterozygous for truncation mutation in the <i>Apc</i> gene; WT (+/+), C57BL6/J mice wild-type for Apc gene; DEF, B-vitamin deficient; CTRL, B-vitamin replete; SUPP, B-vitamin supplemented; M, male; F, female.</p

Effect of paternal B vitamin supplementation on hepatic gene expression and triglyceride concentration in female offspring.

<p>Gene expression levels are expressed as Fragments Per Kilobase Of Exon Per Million Fragments Mapped (FPKM). Triglycerides are expressed as μg/mg protein. CTRL, control; SUPP, supplemented (father’s diet).^a q<0.05, ^b p = 0.002 vs CTRL.</p

OTU table

QIIIME output showing relative abundance of bacterial taxa in stool from each mous

Impact of obesity and intestinal tumor presence on the fecal metabolome of mice.

<p>Low and high fat fed mice are compared in the first column (A,D,G). Low fat fed and genetically obese mice are compared in the second column (B,E,H). Mice with and without intestinal tumors are compared in the third column (C,F,I). The top row (A-C) shows heat maps of top 25 most significantly different metabolites for each comparison (p<0.05); color represents normalized metabolite concentration from low (blue) to high (red). The second row (D-F) shows discrimination of groups using partial least squares discriminate analysis. The third row (G-I) shows the metabolites most strongly influencing discrimination by the partial least squares discriminate analysis. The Variable Importance In Projection (VIP) score is the weighted sum of squares for the partial least-squares loadings with the amount of variance explained by each component taken into account.</p