Prostaglandin E2 (PGE2) has been linked to a higher risk of colorectal cancer. PGE2 in colon tissue can be reduced by increasing dietary eicosapentaenoic acid (EPA). The dose-dependent relationships between dietary EPA, serum EPA:arachidonate (AA) ratio, urinary PGE2 metabolites and colonic eicosanoids were evaluated to develop biomarkers for prediction of colonic PGE2. Male rats were fed diets containing EPA:ω6 fatty acid ratios of 0, 0.1, 0.2, 0.4, or 0.6 for five weeks. Increasing the dietary EPA:ω6 fatty acid ratio increased EPA:AA ratios in serum and in the proximal, transverse and distal colon (p<0.001). The urinary PGE2 metabolite was reduced (p=0.006). EPA rich diets reduced colonic tissue PGE2 concentrations by 58–66% and increased PGE3 by 19–28 fold. Other arachidonic acid-derived eicosanoids were reduced by 35–83%. The changes were not linear, with the largest changes in eicosanoids observed with the lower doses. A mathematical model predicts colonic tissue eicosanoids from the EPA:AA ratio in serum and the EPA dose. Every 10% increase in serum EPA:AA was associated with a 2% decrease in the (geometric) mean of PGE2 in the distal colon. These mathematical relationships can now be applied to individualized EPA dosing in clinical trials.
Colon; Eicosanoids; Prostaglandin; Fatty Acids
Yes-associated protein 1 (YAP1) is a transcriptional coactivator in the Hippo signaling pathway. Increased YAP1- activity promotes the growth of tumors, including that of colorectal cancer (CRC). Verteporfin, a drug that enhances phototherapy to treat neovascular macular degeneration, is an inhibitor of YAP1. Here, we found that verteporfin inhibited tumor growth independently of its effects on YAP1 or the related protein TAZ in genetic or chemical-induced mouse models of CRC, in patient-derived xenografts and in enteroid models of CRC. Instead, verteporfin exhibited in vivo selectivity for killing tumor cells in part by impairing the global clearance of high molecular weight oligomerized proteins, particularly p62 (a sequestrome involved in autophagy) and STAT3 (a transcription factor). Verteporfin inhibited cytokine-induced STAT3 activity and cell proliferation and reduced the viabilty of cultured CRC cells. Although verteporfin accumulated to a greater extent in normal cells than in tumor cells in vivo, experiments with cultured cells indicated that the normal cells efficiently cleared verteporfin-induced protein oligomers through autophagic and proteasomal pathways. Culturing CRC cells in hypoxic or nutrient-deprived conditions (modeling a typical CRC microenvironment) impaired the clearance of protein oligomers and resulted in cell death; whereas culturing cells in normoxic or glucose-replete conditions protected cell viability and proliferation in the presence of verteporfin. Furthermore, verteporfin suppressed the proliferation of other cancer cell lines even in the absence of YAP1, suggesting that verteporfin may be effective against multiple types of solid cancers.
The challenges of clinical screening of cancer risk reductive
interventions (“chemopreventive”) have slowed progress in
deployment of therapeutics to reverse or delay the carcinogenesis process. The
preoperative or window of opportunity design clinical trial design enrolls
subjects rapidly, has short study periods and quantifies tissue biomarkers that
reflect both anticarcinogenesis mechanism of the risk reductive intervention and
key molecular events of the carcinogenesis process for a specific epithelial
target. High subject screened to on study ratios reduce the efficiency and
increase cost of this research strategy. Small sized tissue samples obtained by
minimally invasive endoscopic technologies limits the number of biomarkers that
can be detected and quantified, forcing investigators into choosing either a
broad based but superficial muti-mechanism exploration of signaling
intermediates or a more focused analysis of multiple molecular events in a
linear signaling specific pathway. More efficient strategies of the future might
involve isolation and expansion of pluripotent cells from at risk epithelium or
intraepithelial neoplastic lesions. Such a strategy would allow interrogation of
key carcinogenesis associated pathways and mechanisms in representative primary
single cell cultures amenable to genomic, proteomics, or transfection based
The available evidence indicates that γ-tocopherol has more potential for colon cancer prevention than α-tocopherol, but little is known about the effects of foods and supplements on tocopherol levels in human colon. This study randomized 120 subjects at increased colon cancer risk to either a Mediterranean or a Healthy Eating diet for six months. Supplement use was reported by 39% of the subjects, and vitamin E intake from supplements was 2-fold higher than that from foods. Serum α-tocopherol at baseline was positively predicted by dietary intakes of synthetic vitamin E in foods and supplements but not by natural α-tocopherol from foods. For serum γ-tocopherol, dietary γ-tocopherol was not a predictor, but dietary α-tocopherol was a negative predictor. Unlike with serum, the data supported a role for metabolic factors, and not a direct effect of diet, in governing concentrations of both α- and γ-tocopherol in colon. The Mediterranean intervention increased intakes of natural α-tocopherol, which is high in nuts, and decreased intakes of γ-tocopherol, which is low in olive oil. These dietary changes had no significant effects on colon tocopherols. The impact of diet on colon tocopherols therefore appears to be limited.
Curcumin is a polyphenol, found in the spice turmeric, that has promising anticancer properties, but previous studies suggest that absorption of curcumin may be limited.
This study examined the pharmacokinetics of a curcumin preparation in healthy human volunteers 0.25-72 hours after a single oral dose. Curcumin was administered at doses of 10 g (N=6) and 12 g (N=6). Subjects were randomly allocated to dose level for a total of 6 subjects at each dose level. Serum samples were assayed for free curcumin, for its glucuronide and for it sulfate conjugate. The data were fit to a one-compartment absorption and elimination model.
Using an HPLC assay with a limit of detection of 50 ng/mL, only one subject had detectable free curcumin at any of the 14 time points assayed, but curcumin glucuronides and sulfates were detected in all subjects. Based on the PK model, AUC for the 10g and 12 g doses was estimated (mean±standard error) to be 35.33±3.78 and 26.57±2.97 μg/mL × hr, respectively, while Cmax was 2.30±0.26 and 1.73±0.19 μg/mL. The tmax and t1/2 were estimated to be 3.29±0.43 hr and 6.77±0.83 hr. The ratio of glucuronide:sulfate was 1.92:1. The curcumin conjugates were present as either glucuronide or sulfate, not mixed conjugates.
Curcumin is absorbed after oral dosing in humans and can be detected as glucuronide and sulfate conjugates in plasma.
Chemoprevention; Pharmacokinetics; Curcumin; Metabolism; Clinical trial
Colorectal cancer (CRC) remains a significant cause of mortality. Inhibitors of cyclooxygenase (COX) and thus prostaglandin E2, are promising CRC preventives, but have significant toxicities. Ginger has been shown to inhibit COX, to decrease the incidence and multiplicity of adenomas, and decrease PGE2 concentrations in subjects at normal risk for CRC. This study was conducted to determine the effects of 2.0 g/d of ginger given orally on the levels of PGE2, leukotriene B4 (LTB4), 13-hydroxy-octadecadienoic acids, and 5-, 12-, & 15-hydroxy-eicosatetraenoic acid, in the colonic mucosa of subjects at increased risk for CRC. We randomized 20 subjects to 2.0 g/d ginger or placebo for 28 d. At baseline and Day 28, a flexible sigmoidoscopy was used to obtain colon biopsies. A liquid chromatography mass spectrometry method was used to determine eicosanoid levels in the biopsies, and levels were expressed per amount of protein or free arachidonic acid (AA). There was a significant decrease in AA between baseline and Day 28 (P = 0.05) and significant increase in LTB4 (P = 0.04) when normalized to protein, in subjects treated with ginger versus placebo. No other changes in eicosanoids were observed. There was no difference between the groups in total adverse events (AE; P = 0.06). Ginger lacks the ability to decrease eicosanoid levels in people at increased risk for CRC. Ginger did appear to be both tolerable and safe; and could have chemopreventive effects through other mechanisms. Further investigation should focus on other markers of CRC risk in those at increased CRC risk.
cancer risk reductive; prostaglandins; lipoxygenase; inflammation; zingiber
A robust and sensitive ultra-low flow liquid chromatography (UFLC) method that can reproducibly, at reasonable cost, detect low concentrations of piperine from human plasma is necessary. Piperine in plasma was separated and quantified by a gradient method using ultraviolet detection at a maximal absorbance wavelength of 340 nm. An aliquot was injected onto a reversed-phase column Waters SymmetryShield, 2.1 × 100 mm, 3.5 μm, C18 column, attached to a Waters absorbosphere, 4.6 × 30 mm, C18 guard column and eluted with a mobile phase containing a mixture of acetonitrile/water/ acetic acid (25:74.9:0.1, v/v/v) on line A and acetonitrile/acetic acid (99.9:0.1, v/v) on line B. The flow rate was 0.3 mL/min. The gradient method consisted of an opening condition of 20% pump B, with a linear increase to 37% pump B over 8 min, then a linear increase to 100% pump B at 11 min, 2 min at 100% pump B, and then a return to the opening condition (20% pump B) via a linear gradient over 2 min, followed by 5 min re-equilibration at opening conditions. The total run time was 20 min for each sample. All samples were processed protected from ambient light to avoid isomerization of piperine. The plasma assay was linear with R = 0.9995, with a lower limit of detection [signal-to-noise (S/N) > 5:1] of 100 pg of piperine loaded into the analytical system with acceptable accuracy and precision. Extraction recoveries of piperine from human plasma were 88% for quality control high (QCH), 93% for quality control medium (QCM), and 90% for quality control low (QCL), and the matrix effect was <12%. Piperine was quantifiable from a 50 mg oral dose given to human volunteers. A UFLC method for the rapid assay of human plasma with sensitivity to detect as low as 5 ng/mL piperine was developed. The method sensitivity equals that of liquid chromatography/tandem mass spectrometry (LC/MSMS) methods with much less cost.
Liquid chromatography assay; piperine; natural compounds; bioavailability
Human DNA fragments, as well a as whole colonocytes, can be found in stool and interrogated for mutations associated with carcinogenesis. Multiplexed panels of point mutations in fecal DNA improved the sensitivity of cancer detection (51.6%; 95% CI, 34.8%–68%) compared with fecal occult blood testing (12.9%; 95% CI, 5.1–28.9). However, the multiplex panels are not more sensitive than fecal occult blood testing in detecting advanced adenomas. Markers of epigenetic events, such as DNA methylation of gene promoters in genes not previously known to be associated with carcinogenesis or colorectal cancer, have recently been shown to be potential markers for early detection. Future approaches to improve sensitivity of fecal DNA detection of colorectal adenocarcinoma may require the inclusion of epigenetic biomarkers, the use of colonocytes isolated from feces, or both.
We report on a high-dimensional method to globally profile glycoproteins that are modified with sialyl Lewis A or Lewis X glycans. Specifically, glycoproteins in serum or plasma are fractionated on a high-density antibody microarray (i.e., each are localized to their specific antibody spot) and are specifically detected via fluorescently labeled anti-sialyl Lewis A or anti- Lewis X antibodies with quantification in a microarray scanner. Non-glycosylated proteins or glycoproteins with other glycan motifs do not interfere with this assay. The whole process is very rapid and applicable for high-throughput screening without the need for purification of glycoproteins from the samples. Using these methods, sialyl Lewis A or Lewis X moieties were found to be expressed on many previously unreported secreted or membrane associated proteins. Furthermore, the combination of sialyl Lewis A or Lewis X content with protein level increased the ability of certain glycoproteins to distinguish 30 patients with stage III and IV colon cancer from 60 control samples. Thus, this highly sensitive method is capable of discovering novel specific glycan modifications on proteins, many of which will likely be useful for disease detection and monitoring.
glycoproteins; glycans; sialyl Lewis A; Lewis X; cancer biomarker; antibody array
Curcumin is derived from the spice tumeric and has anti-inflammatory and antineoplastic effects in vitro and in animal models, including preventing aberrant crypt foci (ACF) and adenomas in murine models of colorectal carcinogenesis. Inhibiting the production of the procarcinogenic eicosanoids prostaglandin E2 (PGE2) and 5-hydroxyeicosatetraenoic acid (5-HETE) can suppress carcinogenesis in rodents. Curcumin reduces mucosal concentrations of PGE2 (via inhibition of cyclooxygenases 1 and 2) and 5-HETE (via inhibition of 5-lipoxygenase) in rats. Although preclinical data support curcumin acitivity in many sites, the reported poor bioavailability of this agent supports its use in the colorectum We assessed the effects of oral curcumin (2 g or 4 g per day for 30 days) on PGE2 within ACF (primary endpoint), 5-HETE, ACF number, and proliferation in a non-randomized, open-label clinical trial in 44 eligible smokers with 8 or more ACF on screening colonoscopy. We assessed pre- and post-treatment concentrations of PGE2 and 5-HETE by liquid chromatography tandem mass spectroscopy in ACF and normal-tissue biopsies, ACF number via rectal endoscopy, proliferation by Ki-67 immunohistochemistry; and curcumin concentrations by high-performance liquid chromatography in serum and rectal mucosal samples. 41 Subjects completed the study. Neither dose of curcumin reduced PGE2 or 5-HETE within ACF or normal mucosa or Ki-67 in normal mucosa. A significant 40% reduction in ACF number occurred with the 4 g dose (P < 0.005); while ACF were not reduced in the 2 g group. This reduction was associated with a significant change in plasma curcumin/conjugate levels pre- and post-treatmeeng (5-fold increase; P = 0.009) in the 4 g group. Curcumin was well tolerated at both 2 g and 4g. Our data suggest that curcumin can decrease ACF number, and this is potentially mediated by curcumin conjugates delivered systemically.
ACF; Tobacco; Curcumin; Colon cancer
Goals of work
Ginger has been used to treat numerous types of nausea and vomiting. Ginger has also been studied for its efficacy for acute chemotherapy-induced nausea and vomiting (CINV). However, its efficacy for delayed CINV in a diverse oncology population is unknown.
Materials and methods
We performed a randomized, double-blind, placebo-controlled trial in 162 patients with cancer who were receiving chemotherapy and had experienced CINV during at least one previous round of chemotherapy. All participants were receiving a 5-HT3 receptor antagonists and/or aprepitant. Participants were randomized to receive either 1.0 g ginger, 2.0 g ginger daily, or matching placebo for 3 days. The primary outcome was change in the prevalence of delayed CINV. Secondary outcomes included acute prevalence of CINV, acute and delayed severity of CINV, and assessment of blinding.
There were no differences between groups in the prevalence of delayed nausea or vomiting, prevalence of acute CINV, or severity of delayed vomiting or acute nausea and vomiting. Participants who took both ginger and aprepitant had more severe acute nausea than participants who took only aprepitant. Participants were able to accurately guess which treatment they had received. Ginger appeared well tolerated, with no difference in all adverse events (AEs) and significantly less fatigue and miscellaneous AEs in the ginger group.
Ginger provides no additional benefit for reduction of the prevalence or severity of acute or delayed CINV when given with 5-HT3 receptor antagonists and/or aprepitant.
Ginger; Apripetant; Chemotherapy-induced nausea and vomiting
In order to advance a culture model of human colonic neoplasia, we developed methods for the isolation and in vitro maintenance of intact colonic crypts from normal human colon tissue and adenomas. Crypts were maintained in three-dimensional Matrigel culture with a simple, serum-free, low Ca2+ (0.15 mM) medium. Intact colonic crypts from normal human mucosa were viably maintained for 3–5 days with preservation of the in situ crypt-like architecture, presenting a distinct base and apex. Abnormal structures from adenoma tissue could be maintained through multiple passages (up to months), with expanding buds/tubules. Immunohistochemical markers for intestinal stem cells (Lgr5), growth (Ki67), differentiation (E-cadherin, cytokeratin 20 (CK20) and mucin 2 (MUC2)) and epithelial turnover (Bax, cleaved Caspase-3), paralleled the changes in function. The epithelial cells in normal crypts followed the physiological sequence of progression from proliferation to differentiation to dissolution in a spatially and temporally appropriate manner. Lgr5 expression was seen in a few basal cells of freshly isolated crypts, but was not detected after 1–3 days in culture. After 24 h in culture, crypts from normal colonic tissue continued to show strong Ki67 and MUC2 expression at the crypt base, with a gradual decrease over time such that by days 3–4 Ki67 was not expressed. The differentiation marker CK20 increased over the same period, eventually becoming intense throughout the whole crypt. In adenoma-derived structures, expression of markers for all stages of progression persisted for the entire time in culture. Lgr5 showed expression in a few select cells after months in culture. Ki67 and MUC2 were largely associated with the proliferative budding regions while CK20 was localized to the parent structure. This ex vivo culture model of normal and adenomatous crypts provides a readily accessible tool to help understand the growth and differentiation process in human colonic epithelium.
adenoma; apoptosis; chemoprevention; colon crypt culture; cytokeratin 20; Lgr5; mucin 2
Little is known about dietary effect on colonic nutrient concentrations associated with preventive foods. This study observed 120 persons at increased risk of colon cancer randomized to a Mediterranean versus a Healthy Eating diet for six months. The former targeted increases in whole grains, fruits, vegetables, monounsaturated and n3 fats. Healthy Eating diet was based on Healthy People 2010 recommendations. At baseline, dietary fat and carotenoid intakes were poorly associated (Spearman ρ < 0.4) with serum and colon concentrations. Strong associations were observed between serum and colon measurements of β-cryptoxanthin (ρ = 0.58, p-value < 0.001), α-carotene (ρ = 0.48, p-value < 0.001), and β-carotene (ρ = 0.45, p-value < 0.001). After six months, the Healthy Eating arm increased serum lutein, β- and α-carotene significantly (p-value < 0.05). In the Mediterranean arm the significant increases were in serum lutein, β-cryptoxanthin, β-carotene, monounsaturated and n3 fats. A significant group-by-time interaction (p-value = 0.03) was obtained for monounsaturated fats. Colonic increases in carotenoids and n3 fats were significant only in Healthy Eating arm, while group-by-time interaction were significant for β-carotene (p-value = 0.02), and α-carotene (p-value = 0.03). Changes in colon concentrations were not significantly associated with reported dietary changes. Changes in colon and serum concentrations were strongly associated for β-cryptoxanthin (ρ = 0.56, p-value < 0.001), and α-carotene (ρ = 0.40, p-value < 0.001). The associations between colonic and serum concentrations suggest the potential utility of using serum concentration as a target in dietary interventions aimed at reducing colon cancer risk.
Mediterranean diet; Healthy People diet; Carotenoids; Fatty Acids; Spearman Correlation
The galactose oxidase-Schiff (GOS) reaction detects D-galactose-β-[1,3]-N-acetyl-D-galactosamine. This is a T-antigen expressed in mucus from malignant cells and colonic mucosa adjacent to cancer but not in normal mucosa. Previous studies using a qualitative GOS assay proved to be of limited value for the detection of colorectal neoplasia. We used a newly developed quantitative GOS assay to determine its potential as an early detection biomarker for colorectal cancer. We completed a multi-center, prospective, cross-sectional cohort validation study consisting of 70 normal controls, 23 high-risk normal patients (polyp history or family history of colorectal cancer (CRC) with currently normal colonoscopy), 137 patients with adenomatous polyps, and 69 with colorectal cancers. Prior to colonoscopy, two samples of stool were collected via a rectal exam: one for FOBT, and one for GOS. The area under the ROC curve (AUC) for detecting colonic adenomas and cancer for normal colons, computed with logistic regression was 0.69 for GOS, 0.62 for FOBT, and 0.73 for GOS combined with FOBT. Adding GOS to FOBT did not significantly change the ROC of FOBT alone. GOS does not appear to be a suitable marker of colorectal neoplasia.
Colorectal Neoplasms/diagnosis; Colorectal Neoplasms/prevention & control; Carcinoma/diagnosis; Galactose Oxidase; Predictive Value of Tests
To estimate the effects of ginger on apoptosis, proliferation, and differentiation in the normal-appearing colonic mucosa, we randomized 20 people at increased risk for colorectal cancer to 2.0 g of ginger or placebo daily for 28 days in a pilot trial. Overall expression and distributions of Bax, Bcl-2, p21, hTERT and MIB-1 (Ki-67) in colorectal crypts in rectal mucosa biopsies were measured using automated immunohistochemistry and quantitative image analysis. Relative to placebo, Bax expression in the ginger group decreased 15.6% (p = 0.78) in the whole crypts, 6.6% (p = 0.95) in the upper 40% (differentiation zone) of crypts, and 21.7% (p = 0.67) in the lower 60% (proliferative zone) of crypts; however, there was a 19% increase (p = 0.14) in Bax expression in the upper 40% relative to the whole crypt. While p21 and Bcl-2 expression remained relatively unchanged, hTERT expression in the whole crypts decreased by 41.2% (p = 0.05); the estimated treatment effect on hTERT expression was larger in the upper 40% of crypts (−47.9%; p = 0.04). In the ginger group, MIB-1 expression decreased in the whole crypts, upper 40% of crypts, and lower 60% of crypts by 16.9% (p = 0.39), 46.8% (p = 0.39), and 15.3% (p = 0.41), respectively. These pilot study results suggest that ginger may reduce proliferation in the normal-appearing colorectal epithelium and increase apoptosis and differentiation relative to proliferation—especially in the differentiation zone of the crypts, and support a larger study to further investigate these results.
Differentiation (p21waf1/cip1); Apoptosis (Bax and Bcl-2); Proliferation (MIB-1/Ki-67 and hTERT); Colorectal Cancer; Ginger
Enterolactone and enterodiol, mammalian lignans derived from dietary sources such as flaxseed, sesame seeds, kale, broccoli, and apricots, may impede tumor proliferation by inhibiting activation of nuclear factor kappa B (NFκB) and vascular endothelial growth factor (VEGF). We examined the associations between urinary enterolactone and enterodiol with prostatic tumor expression of NFκB, VEGF, and Ki67 among 147 patients with prostate cancer who participated in a presurgical trial of flaxseed supplementation (30 g/day) for ∼30 days. Urinary enterolignans and tissue biomarkers were determined by high-performance liquid chromatography and immunohistochemistry, respectively. After supplementation, we observed significant correlations between intakes of plant lignan and urinary concentrations of total enterolignans (ρ=0.677, P<.0001), enterolactone (ρ=0.676, P<.0001), and enterodiol (ρ=0.628, P<.0001). Importantly, we observed that total urinary enterolignans and enterolactone were significantly and inversely correlated with Ki67 in the tumor tissue (ρ=−0.217, P=.011, and ρ=−0.230, P=.007, respectively), and a near-significant inverse association was observed for enterodiol (ρ=−0.159, P=.064). An inverse association was observed between enterolactone and VEGF (ρ=−0.143, P=.141), although this did not reach statistical significance. We did not observe an association between enterolignans and NFκB. In conclusion, flaxseed-derived enterolignans may hinder cancer cell proliferation via VEGF-associated pathways.
diet; flaxseed; lignans; phytoestrogens; prostatic neoplasia
This study recruited persons at increased risk of colon cancer to an intensive dietary intervention study that required biopsies of the colon by flexible sigmoidoscopy at baseline and after six months of intervention. A total of 1314 individuals contacted the study, and only 16 individuals indicated that the sigmoidoscopy procedure was an obstacle to study participation. A total of 270 individuals completed a screening visit and signed a screening consent form. Inquiries about the study tended to be fewer in the winter and late summer. Failure to return food records was the most common reason for exclusion. Dietary recall at enrollment indicated that subjects were consuming significantly more vegetables, lower sodium and a lower glycemic load on the day before starting the study versus during the eligibility phase which might have an impact on biomarker measures. This makes it important to capture dietary changes in the period between determination of eligibility and enrollment. Subjects (n=120) were randomized to follow a Healthy Eating or a Mediterranean Diet, each of which required substantial dietary record-keeping. The study completion rate was 78%, and subjects reported high satisfaction with study participation. Of the 93 individuals who completed the study, only one refused the flexible sigmoidoscopy at the final visit. These findings suggest that flexible sigmoidoscopy does not appear to be a barrier for recruitment of high-risk individuals to an intensive dietary intervention trial, but that completing food records can be.
colon biopsy; recruitment; dietary intervention; cancer prevention
Elevated tissue levels of prostaglandin E2 (PGE2), produced by cyclooxygenase (COX) are an early event in colorectal cancer (CRC). Data suggest the efficacy of non-steroidal anti-inflammatory (NSAIDs) drugs, which inhibit COX activity, as cancer preventives; however, side effects of NSAIDs indicate unacceptable limitations. Ginger has been reported to have anti-inflammatory activities with significant CRC preventive potential. We investigated if consumption of 2.0 g ginger daily regulated the level of two key enzymes, which control PGE2 production, COX-1 and NAD+- dependent 15-hydroxyprostaglandin dehydrogenase (15-PGDH).
Thirty participants at normal and twenty participants at increased risk of CRC were randomized and given 2.0 g/day ginger or placebo for 28 days. Flexible sigmoidoscopy was used to obtain colon biopsies at baseline and end of the study. Tissue level of COX-1 and 15-PGDH were assessed using Western Blotting.
After ginger consumption participants at increased risk of CRC, had significantly reduced colonic COX-1 protein level (23.8%± 41) compared to the placebo group (18.9%± 52; p=0.03). Protein levels of 15-PGDH in the colon were unchanged. In normal risk for CRC participants, neither protein levels of COX-1 nor 15-PGDH in the colon were altered by ginger consumption.
Ginger significantly lowered COX-1 protein expression in increased risk participants, but not in normal risk participants at normal for CRC. Ginger did not alter 15-PGDH protein expression in either increased or normal risk participants. Further investigation, in larger studies with a longer ginger intervention is needed to examine the ability of ginger to impact tissue level of prostaglandin.
ginger root extract; cyclooxygenase; 15-hydroxyprostaglandin dehydrogenase; colon cancer risk; cancer risk reduction
Dietary ω3 fatty acids can modulate substrate availability for cyclooxygenases and lipoxygenases, thus modulating downstream eicosanoid formation. This could be an alternative approach to using NSAIDs and other COX inhibitors for limiting PGE2 synthesis in colon cancer prevention. The aims of this study were to evaluate to what extent cyclooxygenase- and lipoxygenase-derived products could be modulated by dietary fish oil in normal colonic mucosa, and to evaluate the role of COX-1 and COX-2 in formation of these products. Mice (wild-type, COX-1 null, or COX-2 null) were fed a diet supplying a broad mixture of fatty acids present in European/American diets, supplemented with either olive oil (oleate control diet) or menhaden (fish) oil ad libitum for 9–11 wk. Colonic eicosanoid levels were measured by LC-MS/MS, and proliferation was assessed by Ki67 immunohistochemistry. Dietary alteration of colonic arachidonic acid: eicosapentaenoic ratios resulted in large shifts in formation of cyclooxygenase and lipoxygenase metabolites. COX-1 knockout virtually abolished PGE2 formation but interestingly 12-HETE and 15-HETE formation was increased. The large changes in eicosanoid profiles were accompanied by relatively small changes in colonic crypt proliferation, but such changes in eicosanoid formation might have greater biological impact upon carcinogen challenge. These results indicate that in normal colon, inhibition of COX-2 would have little effect on reducing PGE2 levels.
colon cancer; fish oil; cyclooxygenase; prostaglandin E2; hydroxyeicosatetraenoic acids; EPA
The anti-proliferative effects of 1α,25-dihydroxyvitamin D3 (1,25-D3, calcitriol, the active form of vitamin D) are mediated by the nuclear vitamin D receptor (VDR). In the present study, we characterized VDR expression in lung adenocarcinoma (AC).
We examined VDR mRNA expression using a quantitative real-time PCR (qRT-PCR) in 100 patients who underwent surgery for lung AC. In a subset of these patients (n = 89), we examined VDR protein expression using immunohistochemistry. We also examined the association of VDR protein expression with circulating serum levels of 25-hydroxyvitamin D3 (25-D3) and 1,25-D3. The antiproliferative effects and cell cycle arrest of 1,25-D3 were examined using lung cancer cell lines with high (SKLU-1) as well as low (A549) expression of VDR mRNA.
Higher VDR expression correlates with longer survival after adjusting for age, sex, disease stage and tumor grade (HR 0.73, 95% CI 0.58–0.91). In addition, there was a positive correlation (r = 0.38) between serum 1,25-D3 and tumor VDR protein expression. A greater anti-proliferative effect of 1,25-D3 was observed in high compared to low VDR-expressing cell lines; these effects corresponded to G1 cell cycle arrest; this was associated with a decline in cyclin D1, S-phase kinase protein 2 (Skp2), retinoblastoma (Rb) and minichromosome maintenance 2 (MCM2) proteins involved in S-phase entry.
Increased VDR expression in lung AC is associated with improved survival. This may relate to a lower proliferative status and G1 arrest in high VDR-expressing tumors.
VDR; Vitamin D; 1,25-D3; Lung Adenocarcinoma; Survival
Longitudinal blood collections from cohort studies provide the means to search for proteins associated with disease prior to clinical diagnosis. We investigated plasma samples from the Women’s Health Initiative (WHI) cohort to determine quantitative differences in plasma proteins between subjects subsequently diagnosed with colorectal cancer (CRC) and matched controls that remained cancer free during the period of follow-up. Proteomic analysis of WHI samples collected prior to diagnosis of CRC resulted in the identification of six proteins with significantly (p <0.05) elevated concentrations in cases compared to controls. Proteomic analysis of two colorectal cancer cell lines showed 5 of the 6 proteins were produced by cancer cells. MAPRE1, IGFBP2, LRG1 and CEA were individually assayed by enzyme linked immunosorbent assay (ELISA) in 58 pairs of newly diagnosed CRC samples and controls and yielded significant elevations (p <0.05) among cases relative to controls. A combination of these four markers resulted in an ROC with an AUC=0.841 and 57% sensitivity at 95% specificity. This combination rule was tested in an independent set of WHI samples collected within 7 months prior to diagnosis from cases and matched controls resulting in 41% sensitivity at 95% specificity. A panel consisting of CEA, MAPRE1, IGFBP2 and LRG1 has predictive value in pre-diagnostic colorectal cancer plasmas.
colorectal cancer; risk markers; Pre-Diagnostic samples
Colorectal cancers associated with Lynch syndrome (LS) are characterized by deficient DNA mismatch repair (MMR) function. Our aim was to evaluate the prevalence of microsatellite instability (MSI) and loss of MMR protein expression in LS-associated polyps. Sixty two colorectal polyps – 37 adenomas (APs), 23 hyperplastic polyps (HPs), and 2 sessile serrated polyps (SSPs) – from 34 subjects with germline MMR gene mutations were tested for MSI using a single pentaplex PCR for five mononucleotide repeat microsatellite markers, and also for expression of MLH1, MSH2, MSH6, and PMS2 proteins by immunohistochemistry (IHC). High-level MSI (MSI-H) was seen in 15/37 (41%) APs, 1/23 (4%) HPs, and 1/2 (50%) SSPs. Loss of MMR protein expression was seen in 18/36 (50%) APs, 0/21 HPs, and 0/2 SSPs. APs ≥8 mm were significantly more likely to demonstrate MSI-H (OR = 9.98, 95% CI: 1.52-65.65, p = 0.02) and deficient MMR protein expression (OR = 3.17, 95% CI: 1.20-8.37, p = 0.02) compared with those <8 mm. All (6/6) APs ≥10 mm demonstrated both MSI-H and loss of MMR protein expression by IHC. Our finding that the prevalence of MMR deficiency increases with the size of APs suggests that loss of MMR function is a late event in LS-associated colorectal neoplasia. Although testing large APs may be of value in the diagnostic evaluation of patients with suspected LS, the absence of an MMR deficient phenotype in an adenoma cannot be considered strong evidence against LS, as it is with colorectal carcinomas.
Lynch Syndrome; adenomas; microsatellite instability
Inhibitors of cyclooxygenase (COX) indicate that up-regulation of inflammatory eicosanoids produced by COX, and in particular prostaglandin E2 (PGE2), are early events in the development of colorectal cancer (CRC). Ginger has demonstrated down regulation of COX in vitro and decreased incidence/ multiplicity of adenomas in rats. This study was conducted to determine if 2.0 g/day of ginger could decrease the levels of PGE2, 13-hydroxy-octadecadienoic acids (13-HODE), and 5-, 12-, & 15-hydroxyeicosatetraenoic acid (5-, 12-, & 15-HETE), in the colon mucosa of healthy volunteers. To investigate this aim we randomized 30 subjects to 2.0 g/day ginger or placebo for 28 days. Flexible sigmoidoscopy at baseline and day 28 was used to obtain colon biopsies. A liquid chromatography mass spectrometry method was used to determine eicosanoid levels in the biopsies, and levels were expressed per protein or per free arachidonic acid. There were no significant differences in mean percent change between baseline and day 28 for any of the eicosanoids, when normalized to protein. There was a significant decrease in mean percent change in PGE2 (p=0.05) and 5-HETE (p=0.04), and a trend toward significant decreases in 12-HETE (p=0.09) and 15-HETE (p=0.06) normalized to free arachidonic acid. There was no difference between the groups in terms of total adverse events (AE) (p=0.55). Based on these results, it appears that Ginger has the potential to decrease eicosanoid levels, perhaps by inhibiting their synthesis from arachidonic acid. Ginger also appeared to be tolerable and safe. Further investigation in people at high risk for CRC seems warranted.
Cancer Risk Reductive; Eicosanoids; Colorectal Cancer; Inflammation; and Ginger
The balance of putative pro- and anti-inflammatory lipoxygenase (LOX)-derived S-hydroxyeicosatetraenoic acids (S-HETEs) in colon mucosa is a potential target for modulating colon cancer risk and progression. The biological effects of S-HETEs and R-HETEs (produced by distinct pathways) may differ, but levels of these compounds in colon are unknown. The objective of this study was to develop chiral methods to characterize HETE enantiomers in colonic mucosa and evaluate the effects of fish oil on HETE formation. C57BL/6 mice (COX-1 null, COX-2 null, wild-type) were fed a diet supplemented with either olive oil or menhaden oil for 11 weeks, and R/S-HETEs in colonic mucosa were quantified by chiral LC-MS/MS. The R-enantiomer comprised 60-72% of 5-HETE, 18-58% of 15-HETE and 1-16% of 12-HETE in colonic mucosa, suggesting that non-LOX sources contribute to HETE profiles. Fish oil reduced levels of both R- and S-HETEs, and increased the preponderance of the R-enantiomers (particularly 12- and 15-HETEs). There was apparent shunting of arachidonic acid to12/15-LOX in the COX-1 null animals. This is the first report of the enantiomeric composition of HETEs in the colon in vivo.
experimental; lipoxygenase; hydroxyeicosatetraenoic acid; enantiomer; colon