Showing papers in "Cancer Prevention Research in 2014"

The Human Gut Microbiome as a Screening Tool for Colorectal Cancer

Abstract: Recent studies have suggested that the gut microbiome may be an important factor in the development of colorectal cancer. Abnormalities in the gut microbiome have been reported in patients with colorectal cancer; however, this microbial community has not been explored as a potential screen for early-stage disease. We characterized the gut microbiome in patients from three clinical groups representing the stages of colorectal cancer development: healthy, adenoma, and carcinoma. Analysis of the gut microbiome from stool samples revealed both an enrichment and depletion of several bacterial populations associated with adenomas and carcinomas. Combined with known clinical risk factors of colorectal cancer (e.g., BMI, age, race), data from the gut microbiome significantly improved the ability to differentiate between healthy, adenoma, and carcinoma clinical groups relative to risk factors alone. Using Bayesian methods, we determined that using gut microbiome data as a screening tool improved the pretest to posttest probability of adenoma more than 50-fold. For example, the pretest probability in a 65-year-old was 0.17% and, after using the microbiome data, this increased to 10.67% (1 in 9 chance of having an adenoma). Taken together, the results of our study demonstrate the feasibility of using the composition of the gut microbiome to detect the presence of precancerous and cancerous lesions. Furthermore, these results support the need for more cross-sectional studies with diverse populations and linkage to other stool markers, dietary data, and personal health information.

Metformin and Cancer Risk and Mortality: A Systematic Review and Meta-Analysis taking into account Biases and Confounders

Abstract: Previous meta-analyses have shown that the antidiabetic agent metformin is associated with reduced cancer incidence and mortality. However, this effect has not been consistently demonstrated in animal models and recent epidemiologic studies. We performed a meta-analysis with a focus on confounders and biases, including body mass index (BMI), study type, and time-related biases. We identified 71 articles published between January 1, 1966, and May 31, 2013, through Pubmed, ISI Web of Science (Science Citation Index Expanded), Embase, and the Cochrane library that were related to metformin and cancer incidence or mortality. Study characteristics and outcomes were abstracted for each study that met inclusion criteria. We included estimates from 47 independent studies and 65,540 cancer cases in patients with diabetes. Overall cancer incidence was reduced by 31% [summary relative risk (SRR), 0.69; 95% confidence interval (CI), 0.52-0.90], although between-study heterogeneity was considerable (I(2) = 88%). Cancer mortality was reduced by 34% (SRR, 0.66; 95% CI, 0.54-0.81; I(2) = 21%). BMI-adjusted studies and studies without time-related biases also showed significant reduction in cancer incidence (SRR, 0.82; 95% CI, 0.70-0.96 with I(2) = 76% and SRR, 0.90; 95% CI, 0.89-0.91 with I(2) = 56%, respectively), albeit with lesser magnitude (18% and 10% reduction, respectively). However, studies of cancer mortality and individual organ sites did not consistently show significant reductions across all types of analyses. Although these associations may not be causal, our results show that metformin may reduce cancer incidence and mortality in patients with diabetes However, the reduction seems to be of modest magnitude and not affecting all populations equally. Clinical trials are needed to determine if these observations apply to nondiabetic populations and to specific organ sites.

Targeting Apoptosis Pathways in Cancer and Perspectives with Natural Compounds from Mother Nature

Abstract: Although the incidences are increasing day after day, scientists and researchers taken individually or by research group are trying to fight against cancer by several ways and also by different approaches and techniques. Sesquiterpenes, flavonoids, alkaloids, diterpenoids, and polyphenolic represent a large and diverse group of naturally occurring compounds found in a variety of fruits, vegetables, and medicinal plants with various anticancer properties. In this review, our aim is to give our perspective on the current status of the natural compounds belonging to these groups and discuss their natural sources, their anticancer activity, their molecular targets, and their mechanism of actions with specific emphasis on apoptosis pathways, which may help the further design and conduct of preclinical and clinical trials. Unlike pharmaceutical drugs, the selected natural compounds induce apoptosis by targeting multiple cellular signaling pathways including transcription factors, growth factors, tumor cell survival factors, inflammatory cytokines, protein kinases, and angiogenesis that are frequently deregulated in cancers and suggest that their simultaneous targeting by these compounds could result in efficacious and selective killing of cancer cells. This review suggests that they provide a novel opportunity for treatment of cancer, but clinical trials are still required to further validate them in cancer chemotherapy.

Understanding the premalignant potential of atypical hyperplasia through its natural history: a longitudinal cohort study.

Abstract: Atypical hyperplasia is a high-risk premalignant lesion of the breast, but its biology is poorly understood. Many believe that atypical ductal hyperplasia (ADH) is a direct precursor for low-grade ductal breast cancer, whereas atypical lobular hyperplasia (ALH) serves as a risk indicator. These assumptions underlie current clinical recommendations. We tested these assumptions by studying the characteristics of the breast cancers that develop in women with ADH or ALH. Using the Mayo Benign Breast Disease Cohort, we identified all women with ADH or ALH from 1967 to 2001 and followed them for later breast cancers, characterizing side of breast cancer versus side of atypia; time to breast cancer; type, histology, and grade of breast cancer, looking for patterns consistent with precursors versus risk indicators. A total of 698 women with atypical hyperplasia were followed a mean of 12.5 years; 143 developed breast cancer. For both ADH and ALH, there is a 2:1 ratio of ipsilateral to contralateral breast cancer. The ipsilateral predominance is marked in the first 5 years, consistent with a precursor phenotype for both ADH and ALH. For both, there is a predominance of invasive ductal cancers with 69% of moderate or high grade. Twenty-five percent are node positive. Both ADH and ALH portend risk for ductal carcinoma in situ and invasive breast cancers, predominantly ductal, with two thirds moderate or high grade. The ipsilateral breast is at especially high risk for breast cancer in the first 5 years after atypia, with risk remaining elevated in both breasts long term. ADH and ALH behave similarly in terms of later breast cancer endpoints.

Nutrition and physical activity cancer prevention guidelines, cancer risk, and mortality in the women's health initiative

Abstract: Healthy lifestyle behaviors are recommended to reduce cancer risk and overall mortality. Adherence to cancer-preventive health behaviors and subsequent cancer risk has not been evaluated in a diverse sample of postmenopausal women. We examined the association between the American Cancer Society (ACS) Nutrition and Physical Activity Cancer Prevention Guidelines score and risk of incident cancer, cancer-specific mortality, and all-cause mortality in 65,838 postmenopausal women enrolled in the Women's Health Initiative Observational Study. ACS guidelines scores (0-8 points) were determined from a combined measure of diet, physical activity, body mass index (current and at age 18 years), and alcohol consumption. After a mean follow-up of 12.6 years, 8,632 incident cancers and 2,356 cancer deaths were identified. The highest ACS guidelines scores compared with the lowest were associated with a 17% lower risk of any cancer [HR, 0.83; 95% confidence interval (CI), 0.75-0.92], 22% lower risk of breast cancer (HR, 0.78; 95% CI, 0.67-0.92), 52% lower risk of colorectal cancer (HR, 0.48; 95% CI, 0.32-0.73), 27% lower risk of all-cause mortality, and 20% lower risk of cancer-specific mortality (HR, 0.80; 95% CI, 0.71-0.90). Associations with lower cancer incidence and mortality were generally strongest among Asian, black, and Hispanic women and weakest among non-Hispanic whites. Behaviors concordant with Nutrition and Physical Activity Cancer Prevention Guidelines were associated with lower risk of total, breast, and colorectal cancers and lower cancer-specific mortality in postmenopausal women.

Adherence to Endocrine Therapy in Breast Cancer Adjuvant and Prevention Settings

Abstract: Adherence to oral endocrine therapy in adjuvant breast cancer settings is a substantial clinical problem. To provide current perspective on adherence to oral endocrine therapies, a comprehensive literature review was conducted. In adjuvant trials, endocrine therapy adherence is relatively high with greater adherence for aromatase inhibitors compared with tamoxifen. In contrast, adherence to adjuvant therapy in clinical practice is relatively poor, with only about 50% of women successfully completing 5-year therapy. Importantly, good adherence (>80% use) has been associated with lower recurrence risk. Endocrine therapy adherence in primary breast cancer prevention trials parallels that seen in adjuvant trials. Factors associated with nonadherence include low recurrence risk perception, side effects, age extremes, medication cost, suboptimal patient-physician communication, and lack of social support. Few prospective studies have evaluated interventions designed to improve adherence. Interventions currently proposed reflect inferences from clinical trial procedures in which clinical contacts are commonly greater than in usual practice settings. In conclusion, for optimal breast cancer outcome, adherence to endocrine therapy must improve. Although general recommendations likely to improve adherence can be made based on clinical trial results and preliminary prospective trial findings, research specifically targeting this issue is needed to establish effective intervention strategies.

Rapid and Sustainable Detoxication of Airborne Pollutants by Broccoli Sprout Beverage: Results of a Randomized Clinical Trial in China

Abstract: Broccoli sprouts are a convenient and rich source of the glucosinolate, glucoraphanin, which can generate the chemopreventive agent, sulforaphane, an inducer of glutathione S-transferases (GST) and other cytoprotective enzymes. A broccoli sprout-derived beverage providing daily doses of 600 μmol glucoraphanin and 40 μmol sulforaphane was evaluated for magnitude and duration of pharmacodynamic action in a 12-week randomized clinical trial. Two hundred and ninety-one study participants were recruited from the rural He-He Township, Qidong, in the Yangtze River delta region of China, an area characterized by exposures to substantial levels of airborne pollutants. Exposure to air pollution has been associated with lung cancer and cardiopulmonary diseases. Urinary excretion of the mercapturic acids of the pollutants, benzene, acrolein, and crotonaldehyde, were measured before and during the intervention using liquid chromatography tandem mass spectrometry. Rapid and sustained, statistically significant (P ≤ 0.01) increases in the levels of excretion of the glutathione-derived conjugates of benzene (61%), acrolein (23%), but not crotonaldehyde, were found in those receiving broccoli sprout beverage compared with placebo. Excretion of the benzene-derived mercapturic acid was higher in participants who were GSTT1-positive than in the null genotype, irrespective of study arm assignment. Measures of sulforaphane metabolites in urine indicated that bioavailability did not decline over the 12-week daily dosing period. Thus, intervention with broccoli sprouts enhances the detoxication of some airborne pollutants and may provide a frugal means to attenuate their associated long-term health risks.

Temporal and spatial evolution of somatic chromosomal alterations: a case-cohort study of Barrett's esophagus.

Abstract: All cancers are believed to arise by dynamic, stochastic somatic genomic evolution with genome instability, generation of diversity, and selection of genomic alterations that underlie multistage progression to cancer. Advanced esophageal adenocarcinomas have high levels of somatic copy number alterations. Barrett's esophagus is a risk factor for developing esophageal adenocarcinoma, and somatic chromosomal alterations (SCA) are known to occur in Barrett's esophagus. The vast majority (∼95%) of individuals with Barrett's esophagus do not progress to esophageal adenocarcinoma during their lifetimes, but a small subset develop esophageal adenocarcinoma, many of which arise rapidly even in carefully monitored patients without visible endoscopic abnormalities at the index endoscopy. Using a well-designed, longitudinal case-cohort study, we characterized SCA as assessed by single-nucleotide polymorphism arrays over space and time in 79 "progressors" with Barrett's esophagus as they approach the diagnosis of cancer and 169 "nonprogressors" with Barrett's esophagus who did not progress to esophageal adenocarcinoma over more than 20,425 person-months of follow-up. The genomes of nonprogressors typically had small localized deletions involving fragile sites and 9p loss/copy neutral LOH that generate little genetic diversity and remained relatively stable over prolonged follow-up. As progressors approach the diagnosis of cancer, their genomes developed chromosome instability with initial gains and losses, genomic diversity, and selection of SCAs followed by catastrophic genome doublings. Our results support a model of differential disease dynamics in which nonprogressor genomes largely remain stable over prolonged periods, whereas progressor genomes evolve significantly increased SCA and diversity within four years of esophageal adenocarcinoma diagnosis, suggesting a window of opportunity for early detection.

Requirement and epigenetics reprogramming of Nrf2 in suppression of tumor promoter TPA-induced mouse skin cell transformation by sulforaphane

Abstract: Nrf2 is a transcription factor that plays critical roles in regulating the expression of cellular defensive antioxidants and detoxification enzymes. However, the role of Nrf2 and Nrf2's epigenetics reprogramming in skin tumor transformation is unknown. In this study, we investigated the inhibitory role and epigenetics of Nrf2 on tumor transformation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in mouse skin epidermal JB6 (JB6 P+) cells and the anticancer effect of sulforaphane (SFN), an isothiocyanate found in cruciferous vegetables. After five days of treatment, SFN significantly inhibited TPA-induced JB6 cellular transformation and SFN enhanced the nuclear translocation of Nrf2 and increased the mRNA and protein levels of the Nrf2 target genes HO-1, NQO1 and UGT1A1. Knockdown of Nrf2 attenuated the induction of Nrf2, HO-1 and NQO1 by SFN, enhanced TPA-induced colony formation and dampened the inhibitory effect of SFN on TPA-induced JB6 transformation. Epigenetics investigation using bisulfite genomic sequencing showed that SFN decreased the methylation ratio of the first 15 CpGs of the Nrf2 gene promoter, which was corroborated by increased Nrf2 mRNA expression. Furthermore, SFN strongly reduced the protein expression of DNA methyltransferases (DNMT1, DNMT3a and DNMT3b). SFN also inhibited the total histone deacetylase (HDAC) activity and decreased the protein expression of HDAC1, HDAC2, HDAC3 and HDAC4. Collectively, these results suggest that the anti-cancer effect of SFN against TPA-induced neoplastic transformation of mouse skin could involve the epigenetic reprogramming of anti-cancer genes such as Nrf2, leading to the epigenetic reactivation of Nrf2 and the subsequent induction of downstream target genes involved in cellular protection.

Repurposing of metformin and aspirin by targeting AMPK-mTOR and inflammation for pancreatic cancer prevention and treatment.

Abstract: Pancreatic cancer, as the fourth leading cause of cancer-related deaths, carries a poor prognosis with a median survival of 6 months and a dismal 5-year survival rate of 3% to 5%. These statistics highlight an urgent need for novel chemopreventive and therapeutic strategies for this malignancy. Metformin and aspirin have been explored as two emerging cancer chemoprevention agents for different types of cancers, including pancreatic cancer. Here, we review the effects of both metformin and aspirin on pancreatic tumorigenesis and their potential actions in pancreatic cancer. Special attention is paid to their effects on the important signaling pathways of pancreatic cancer development as well as possible mechanisms for synergy between these two agents. For metformin, the most important mechanism may involve the inhibition of mTOR signaling via AMP-activated protein kinase (AMPK)-dependent and -independent pathways. For aspirin, the major mechanism is the anti-inflammatory action through the inhibition of COX-1/COX-2 and modulation of the NFκB or STAT3 pathway. In addition, aspirin may activate AMPK, and both agents may affect Notch, Wnt/β-catenin, and other signaling pathways. The combination of metformin and aspirin will provide additive and possibly synergistic effects for the prevention and treatment of pancreatic cancer.

Luteolin Nanoparticle in Chemoprevention: In Vitro and In Vivo Anticancer Activity

Abstract: Cancer prevention (chemoprevention) by using naturally occurring dietary agents has gained immense interest because of the broad safety window of these compounds. However, many of these compounds are hydrophobic and poorly soluble in water. They frequently display low bioavailability, poor systemic delivery, and low efficacy. To circumvent this problem, we explored a novel approach toward chemoprevention using nanotechnology to deliver luteolin, a natural compound present in green vegetables. We formulated water-soluble polymer-encapsulated Nano-Luteolin from hydrophobic luteolin, and studied its anticancer activity against lung cancer and head and neck cancer. In vitro studies demonstrated that, like luteolin, Nano-Luteolin inhibited the growth of lung cancer cells (H292 cell line) and squamous cell carcinoma of head and neck (SCCHN) cells (Tu212 cell line). In Tu212 cells, the IC50 value of Nano-Luteolin was 4.13 μmol/L, and that of luteolin was 6.96 μmol/L. In H292 cells, the IC50 of luteolin was 15.56 μmol/L, and Nano-Luteolin was 14.96 μmol/L. In vivo studies using a tumor xenograft mouse model demonstrated that Nano-Luteolin has a significant inhibitory effect on the tumor growth of SCCHN in comparison to luteolin. Our results suggest that nanoparticle delivery of naturally occurring dietary agents like luteolin has many advantages and may have potential application in chemoprevention in clinical settings.

6-Shogaol from dried ginger inhibits growth of prostate cancer cells both in vitro and in vivo through inhibition of STAT3 and NF-κB signaling.

Abstract: Despite much recent progress, prostate cancer continues to represent a major cause of cancer-related mortality and morbidity in men. Prostate cancer is the most common nonskin neoplasm and second leading cause of death in men. 6-Shogaol (6-SHO), a potent bioactive compound in ginger (Zingiber officinale Roscoe), has been shown to possess anti-inflammatory and anticancer activity. In the present study, the effect of 6-SHO on the growth of prostate cancer cells was investigated. 6-SHO effectively reduced survival and induced apoptosis of cultured human (LNCaP, DU145, and PC3) and mouse (HMVP2) prostate cancer cells. Mechanistic studies revealed that 6-SHO reduced constitutive and interleukin (IL)-6-induced STAT3 activation and inhibited both constitutive and TNF-α-induced NF-κB activity in these cells. In addition, 6-SHO decreased the level of several STAT3 and NF-κB-regulated target genes at the protein level, including cyclin D1, survivin, and cMyc and modulated mRNA levels of chemokine, cytokine, cell cycle, and apoptosis regulatory genes (IL-7, CCL5, BAX, BCL2, p21, and p27). 6-SHO was more effective than two other compounds found in ginger, 6-gingerol, and 6-paradol at reducing survival of prostate cancer cells and reducing STAT3 and NF-κB signaling. 6-SHO also showed significant tumor growth inhibitory activity in an allograft model using HMVP2 cells. Overall, the current results suggest that 6-SHO may have potential as a chemopreventive and/or therapeutic agent for prostate cancer and that further study of this compound is warranted.

The UK Lung Screen (UKLS): Demographic Profile of First 88,897 Approaches Provides Recommendations for Population Screening

Abstract: The UK Lung Cancer Screening trial (UKLS) aims to evaluate low-dose computed tomography (LDCT) lung cancer population screening in the United Kingdom. In UKLS, a large population sample ages 50 to 75 years is approached with a questionnaire to determine lung cancer risk. Those with an estimated risk of at least 5% of developing lung cancer in the next 5 years (using the Liverpool Lung project risk model) are invited to participate in the trial. Here, we present demographic, risk, and response rate data from the first 88,897 individuals approached. Of note, 23,794 individuals (26.8% of all approached) responded positively to the initial questionnaire; 12% of these were high risk. Higher socioeconomic status correlated positively with response, but inversely with risk ( P < 0.001). The 50- to 55-year age group was least likely to participate, and at lowest cancer risk. Only 5% of clinic attendees were ages ≤60 years (compared with 47% of all 88,897 approached); this has implications for cost effectiveness. Among positive responders, there were more ex-smokers than expected from population figures (40% vs. 33%), and fewer current smokers (14% vs. 17.5%). Of note, 32.7% of current smokers and 18.4% of ex-smokers were designated as high risk. Overall, 1,452 of 23,794 positive responders (6.1%) were deemed high risk and attended a recruitment clinic. UKLS is the first LDCT population screening trial, selecting high-risk subjects using a validated individual risk prediction model. Key findings: (i) better recruitment from ex- rather than current smokers, (ii) few clinic attendees ages early 50s, and (iii) representative number of socioeconomically deprived people recruited, despite lower response rates. Cancer Prev Res; 7(3); 362–71. ©2014 AACR .

Methylation Analysis of the FAM19A4 Gene in Cervical Scrapes Is Highly Efficient in Detecting Cervical Carcinomas and Advanced CIN2/3 Lesions

Abstract: Primary testing for human papillomavirus (HPV) in cervical screening requires triage to differentiate women with transient infection from those with persistent infection who require more intensive management given their risk for cervical (pre)cancer. In this study, the clinical performance of a novel methylation marker FAM19A4 for the triage of high-risk (hr)HPV-positive women was evaluated. Using a training-validation set approach, we analyzed a FAM19A4 quantitative methylation-specific PCR (qMSP). The training set comprised hrHPV-positive cervical scrapes of 43 women with cervical intraepithelial neoplasia grade 3 or worse (CIN3+) and 135 women with ≤CIN1. The validation set comprised hrHPV-positive cervical scrapes of 52 women with CIN2+, including 33 CIN3+, 19 CIN2, and 166 women with ≤CIN1. The methylation threshold of FAM19A4 qMSP that gave rise to CIN3+ specificity of 70% in the training set was applied in the validation set. This resulted in CIN3+ sensitivity of 75.8% [95% confidence interval (CI), 61.1–90.4] at 67.0% (95% CI, 60.3–73.8) specificity. Next, the validated qMSP was applied to an independent series of hrHPV-positive cervical scrapes of 22 women with cervical cancer, 29 with advanced CIN2/3 [i.e., women with a known preceding hrHPV infection (PHI) lasting ≥5 years as proxy of longer duration of lesion existence], and 19 with early CIN2/3 (i.e., PHI <5 years). All carcinomas (22/22) and advanced CIN2/3 lesions (29/29) were FAM19A4 methylation–positive, compared with 42.1% (8/19; 95% CI, 19.9–64.3) of early CIN2/3 lesions. In conclusion, FAM19A4 is an attractive triage marker for hrHPV-positive women, with a high reassurance for the detection of cervical carcinoma and advanced CIN2/3 lesions. Cancer Prev Res; 7(12); 1251–7. ©2014 AACR .

Chemoprevention of esophageal cancer with black raspberries, their component anthocyanins, and a major anthocyanin metabolite, protocatechuic acid.

Abstract: Diets containing either freeze-dried black raspberries (BRBs) or their polyphenolic anthocyanins (ACs) have been shown to inhibit the development of N-nitrosomethylbenzylamine (NMBA)-induced esophageal cancer in rats. The present study was conducted to determine whether PCA, a major microbial metabolite of black raspberry (BRB) ACs, also prevents NMBA-induced esophageal cancer in rats. F344 rats were injected with NMBA three times a week for 5 weeks and then fed control or experimental diets containing 6.1% BRBs, an anthocyanin (AC)-enriched fraction derived from BRBs, or protocatechuic acid (PCA). Animals were exsanguinated at weeks 15, 25, and 35 to quantify the development of preneoplastic lesions and tumors in the esophagus, and to relate this to the expression of inflammatory biomarkers. At weeks 15 and 25, all experimental diets were equally effective in reducing NMBA-induced esophageal tumorigenesis, as well as in reducing the expression of pentraxin-3 (PTX3), a cytokine produced by peripheral blood mononuclear cells in response to interleukin (IL)-1β and TNF-α. All experimental diets were also active at reducing tumorigenesis at week 35; however, the BRB diet was significantly more effective than the AC and PCA diets. Furthermore, all experimental diets inhibited inflammation in the esophagus via reducing biomarker (COX-2, iNOS, p-NF-κB, and sEH) and cytokine (PTX3) expression. Overall, our data suggest that BRBs, their component ACs, and PCA inhibit NMBA-induced esophageal tumorigenesis, at least in part, by their inhibitory effects on genes associated with inflammation.

Dietary manipulation of oncogenic microRNA expression in human rectal mucosa: A randomized trial

Abstract: High red meat (HRM) intake is associated with increased colorectal cancer risk, while resistant starch is probably protective. Resistant starch fermentation produces butyrate, which can alter microRNA (miRNA) levels in colorectal cancer cells in vitro; effects of red meat and resistant starch on miRNA expression in vivo were unknown. This study examined whether a HRM diet altered miRNA expression in rectal mucosa tissue of healthy volunteers, and if supplementation with butyrylated resistant starch (HRM+HAMSB) modified this response. In a randomized cross-over design, 23 volunteers undertook four 4-week dietary interventions; an HRM diet (300 g/day lean red meat) and an HRM+HAMSB diet (HRM with 40 g/day butyrylated high amylose maize starch), preceded by an entry diet and separated by a washout. Fecal butyrate increased with the HRM+HAMSB diet. Levels of oncogenic mature miRNAs, including miR17-92 cluster miRNAs and miR21, increased in the rectal mucosa with the HRM diet, whereas the HRM+HAMSB diet restored miR17-92 miRNAs, but not miR21, to baseline levels. Elevated miR17-92 and miR21 in the HRM diet corresponded with increased cell proliferation, and a decrease in miR17-92 target gene transcript levels, including CDKN1A. The oncogenic miR17-92 cluster is differentially regulated by dietary factors that increase or decrease risk for colorectal cancer, and this may explain, at least in part, the respective risk profiles of HRM and resistant starch. These findings support increased resistant starch consumption as a means of reducing risk associated with an HRM diet.

Curcumin Suppresses Proliferation of Colon Cancer Cells by Targeting CDK2

Abstract: Curcumin, the yellow pigment of turmeric found in Southeast Indian food, is one of the most popular phytochemicals for cancer prevention. Numerous reports have demonstrated modulation of multiple cellular signaling pathways by curcumin and its molecular targets in various cancer cell lines. To identify a new molecular target of curcumin, we used shape screening and reverse docking to screen the protein data bank against curcumin. Cyclin dependent kinase 2 (CDK2), a major cell cycle protein, was identified as a potential molecular target of curcumin. Indeed, in vitro and ex vivo kinase assay data revealed a dramatic suppressive effect of curcumin on CDK2 kinase activity. Furthermore, curcumin induced G1 cell cycle arrest, which is regulated by CDK2 in HCT116 cells. Although the expression levels of CDK2 and its regulatory subunit, cyclin E, were not changed, the phosphorylation of Rb, a well-known CDK2 substrate, was reduced by curcumin. Because curcumin induced cell cycle arrest, we investigated the anti-proliferative effect of curcumin on HCT116 colon cancer cells. In this experiment, curcumin suppressed HCT116 cell proliferation effectively. To determine if CDK2 is a direct target of curcumin, CDK2 expression was knocked down in HCT116 cells. As expected, HCT116 sh-CDK2 cells exhibited G1 arrest and reduced proliferation. Because of the low levels of CDK2 in HCT116 sh-CDK2 cells, the effects of curcumin on G1 arrest and cell proliferation were not substantial relative to HCT116 sh-control cells. From these results, we identified CDK2 as a direct target of curcumin in colon cancer cells.

Myeloid lineage-specific deletion of antioxidant system enhances tumor metastasis.

Abstract: Oxidative stress accelerates the pathogenesis of a number of chronic diseases including cancer growth and its metastasis. Transcription factor NF-E2-related factor-2 (Nrf2), which regulates the cellular defense system against oxidative stress, elicits essential protection against chemical-induced carcinogenic insults. We recently demonstrate that the systemic deletion of Nrf2 leads to an increased susceptibility to cancer metastasis, which is associated with aberrant reactive oxygen species (ROS) accumulation in myeloid-derived suppressor cells (MDSC). However, it remains elusive whether cellular antioxidant defense system in the myeloid lineage cells plays indispensable roles for metastatic cancer progression. We herein found that myeloid lineage-specific Nrf2-deficient mice exhibited an increased susceptibility to pulmonary metastasis of the mouse Lewis lung carcinoma cells, and ROS level was more highly elevated in MDSCs of cancer-bearing Nrf2-deficient mice. Similarly, myeloid lineage-specific deletion of selenocysteine-tRNA gene (Trsp), which is essential for synthesis of antioxidant selenoenzymes, resulted in increased number of metastatic nodules along with ROS accumulation in MDSCs of cancer-bearing mice. These results thus indicate that the antioxidant systems directed by Nrf2 and selenoenzymes contribute to the clearance of ROS in MDSCs, efficiently preventing cancer cell metastasis. Consistent with this notion, a synthetic triterpenoid 1-[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl] imidazole (CDDO-Im), a potent Nrf2 inducer, attenuated the ROS production in MDSCs, and thereafter reduced metastatic nodules. Taken together, this study provides compelling lines of evidence that Nrf2 inducer retains therapeutic efficacy against cancer cell metastasis.

A phase Ib study of the effects of black raspberries on rectal polyps in patients with familial adenomatous polyposis.

Abstract: Familial adenomatous polyposis (FAP) is characterized by the early onset of colonic polyposis and a high risk for colorectal cancer. FAP is treated by colectomy followed by lifelong removal of rectal polyps. This study determined whether black raspberries (BRBs) might regress rectal polyps in patients with FAP. Fourteen patients with FAP were treated with BRBs daily for 9 months. Seven patients received BRB powder orally plus two BRB suppositories inserted into the rectum at bedtime. The other 7 received an oral placebo plus the suppositories. Rectal polyp counts and polyp sizes were obtained at time zero and after 9 months of BRB treatment. Polyps and adjacent normal tissue were collected at both time points. The burden (P = 0.036) but not number (P = 0.069) of rectal polyps was significantly decreased. No benefit was noted with the addition of oral BRBs. Three patients were nonresponders. BRBs significantly decreased cellular proliferation, DNA methylation methyl transferase 1 protein expression, and p16 promoter methylation, but not promoter methylation of the Wnt pathway antagonists, SFRP2 and WIF1, in rectal polyps (adenomas) from responders but not from nonresponders. The MBD-seq assay revealed more demethylated transcription start sites (TSS), including those for miRNAs, in BRB-treated adenomas from the responders. In conclusion, BRB suppositories seem sufficient for regressing rectal polyps in patients with FAP.

Impact of vitamin D supplementation on inflammatory markers in African Americans: results of a four-arm, randomized, placebo-controlled trial.

Abstract: African Americans have a disproportionate burden of inflammation-associated chronic diseases such as cancer and lower circulating levels of 25-hydroxyvitamin D [25(OH)D]. The effect of vitamin D3 (cholecalciferol) supplementation on inflammatory markers is uncertain. We conducted a randomized, double-blind, placebo-controlled trial of supplemental oral vitamin D (placebo, 1,000, 2,000, or 4,000 IU/day of vitamin D3 orally for 3 months) in 328 African Americans (median age, 51 years) of public housing communities in Boston, MA, who were enrolled over three consecutive winter periods (2007-2010). Change from 0 to 3 months of plasma levels of 25(OH)D, high-sensitivity C-reactive protein (CRP), interleukin (IL)-6, IL-10, and soluble TNF-α receptor type 2 (sTNF-R2) in 292 (89%) participants were measured. Overall, no statistically significant changes in CRP, IL-6, IL-10, and sTNF-R2 were observed after the vitamin D supplementation period. Baseline CRP was significantly inversely associated with the baseline 25(OH)D level (P < 0.001) in unadjusted and adjusted models. An interaction between baseline 25(OH)D and vitamin D supplementation was observed for outcome change in log CRP (month 3-month 0; P for interaction = 0.04). Within an unselected population of African Americans, short-term exposure to vitamin D supplementation produced no change in circulating inflammatory markers. This study confirms the strong independent association of CRP with 25(OH)D status even after adjusting for body mass index. Future studies of longer supplemental vitamin D3 duration are necessary to examine the complex influence of vitamin D3 on CRP and other chronic inflammatory cytokines for possible reduction of cancer health disparities in African Americans.

Molecular Profiling of Premalignant Lesions in Lung Squamous Cell Carcinomas Identifies Mechanisms Involved in Stepwise Carcinogenesis

Abstract: Lung squamous cell carcinoma (SCC) is thought to arise from premalignant lesions in the airway epithelium; therefore, studying these lesions is critical for understanding lung carcinogenesis. Previous microarray and sequencing studies designed to discover early biomarkers and therapeutic targets for lung SCC had limited success identifying key driver events in lung carcinogenesis, mostly due to the cellular heterogeneity of patient samples examined and the interindividual variability associated with difficult to obtain airway premalignant lesions and appropriate normal control samples within the same patient. We performed RNA sequencing on laser-microdissected representative cell populations along the SCC pathologic continuum of patient-matched normal basal cells, premalignant lesions, and tumor cells. We discovered transcriptomic changes and identified genomic pathways altered with initiation and progression of SCC within individual patients. We used immunofluorescent staining to confirm gene expression changes in premalignant lesions and tumor cells, including increased expression of SLC2A1, CEACAM5, and PTBP3 at the protein level and increased activation of MYC via nuclear translocation. Cytoband enrichment analysis revealed coordinated loss and gain of expression in chromosome 3p and 3q regions, respectively, during carcinogenesis. This is the first gene expression profiling study of airway premalignant lesions with patient-matched SCC tumor samples. Our results provide much needed information about the biology of premalignant lesions and the molecular changes that occur during stepwise carcinogenesis of SCC, and it highlights a novel approach for identifying some of the earliest molecular changes associated with initiation and progression of lung carcinogenesis within individual patients.

Epigenetic DNA methylation of antioxidative stress regulator NRF2 in human prostate cancer.

Abstract: Epigenetic control of NRF2, a master regulator of many critical antioxidative stress defense genes in human prostate cancer (CaP), is unknown. Our previous animal study found decreased Nrf2 expression through promoter CpG methylation/histone modifications during prostate cancer progression in TRAMP mice. In this study, we evaluated CpG methylation of human NRF2 promoter in 27 clinical prostate cancer samples and in LNCaP cells using MAQMA analysis and bisulfite genomic DNA sequencing. Prostate cancer tissue microarray (TMA) containing normal and prostate cancer tissues was studied by immunohistochemistry. Luciferase reporter assay using specific human NRF2 DNA promoter segments and chromatin immunoprecipitation (ChIP) assay against histone modifying proteins were performed in LNCaP cells. Three specific CpG sites in the NRF2 promoter were found to be hypermethylated in clinical prostate cancer samples (BPH

Metformin selectively targets tumor-initiating cells in ErbB2-overexpressing breast cancer models.

Abstract: Metformin is an oral biguanide used for type II diabetes. Epidemiologic studies suggest a link between metformin use and reduced risk of breast and other types of cancers. ErbB2-expressing breast cancer is a subgroup of tumors with poor prognosis. Previous studies demonstrated that metformin is a potent inhibitor of ErbB2–overexpressing breast cancer cells; metformin treatment extends the life span and impedes mammary tumor development in ErbB2 transgenic mice in vivo. However, the mechanisms of metformin associated antitumor activity, especially in prevention models, remain unclear. We report here for the first time that systemic administration of metformin selectively inhibits CD61high/CD49fhigh subpopulation, a group of tumor-initiating cells (TIC) of mouse mammary tumor virus (MMTV)-ErbB2 mammary tumors, in preneoplastic mammary glands. Metformin also inhibited CD61high/CD49fhigh subpopulation in MMTV-ErbB2 tumor-derived cells, which was correlated with their compromised tumor initiation/development in a syngeneic tumor graft model. Molecular analysis indicated that metformin induced downregulation of ErbB2 and EGFR expression and inhibited the phosphorylation of ErbB family members, insulin-like growth factor-1R, AKT, mTOR, and STAT3 in vivo. In vitro data indicate that low doses of metformin inhibited the self-renewal/proliferation of cancer stem cells (CSC)/TICs in ErbB2–overexpressing breast cancer cells. We further demonstrated that the expression and activation of ErbB2 were preferentially increased in CSC/TIC-enriched tumorsphere cells, which promoted their self-renewal/proliferation and rendered them more sensitive to metformin. Our results, especially the in vivo data, provide fundamental support for developing metformin-mediated preventive strategies targeting ErbB2–associated carcinogenesis. Cancer Prev Res; 7(2); 199–210. ©2013 AACR.

Proton pump inhibitors and histamine 2 blockers are associated with improved overall survival in patients with head and neck squamous carcinoma

Abstract: It has been postulated that gastroesophageal reflux plays a role in the etiology of head and neck squamous cell carcinomas (HNSCC) and contributes to complications after surgery or during radiotherapy. Antacid medications are commonly used in patients with HNSCC for the management of acid reflux; however, their relationship with outcomes has not been well studied. Associations between histamine receptor-2 antagonists (H2RA) and proton pump inhibitors (PPI) use and treatment outcomes were determined in 596 patients with previously untreated HNSCC enrolled in our SPORE epidemiology program from 2003 to 2008 (median follow-up 55 months). Comprehensive clinical information was entered prospectively in our database. Risk strata were created on the basis of possible confounding prognostic variables (age, demographics, socioeconomics, tumor stage, primary site, smoking status, HPV16 status, and treatment modality); correlations within risk strata were analyzed in a multivariable model. Patients taking antacid medications had significantly better overall survival (OS; PPI alone: P

The PARP Inhibitors, Veliparib and Olaparib, Are Effective Chemopreventive Agents for Delaying Mammary Tumor Development in BRCA1-deficient Mice

Abstract: Poly-ADP ribose polymerase (PARP) inhibitors are effective for the treatment of BRCA-deficient tumors. Women with these mutations have an increased risk of developing breast cancer and would benefit from effective chemoprevention. This study examines whether the PARP inhibitors, veliparib and olaparib, delay mammary gland tumor development in a BRCA1-deficient (BRCA1(Co/Co);MMTV-Cre;p53(+/-)) mouse model. In dose de-escalation studies, mice were fed with control, veliparib (100 mg/kg diet), or olaparib (200, 100, 50, or 25 mg/kg diet) continuously for up to 43 weeks. For intermittent dosing studies, mice cycled through olaparib (200 mg/kg diet) for 2 weeks followed by a 4-week rest period on control diet. To examine biomarkers, mice were fed with olaparib using the intermittent dosing regimen and mammary glands were evaluated by immunohistochemistry. In mice treated with veliparib or olaparib (200 mg/kg diet), the average age of the first detectable tumor was delayed by 2.4 and 6.5 weeks, respectively, compared with controls. Olaparib also increased the average lifespan of mice by 7 weeks. In dose de-escalation studies, lower concentrations of olaparib delayed tumor development but were less effective than the highest dose. When fed intermittently, olaparib delayed the onset of the first palpable tumor by 5.7 weeks and significantly reduced proliferation and induced apoptosis in hyperplastic mammary glands. In summary, veliparib and olaparib are effective for delaying tumor development and extending the lifespan of BRCA1-deficient mice, and intermittent dosing with olaparib was as effective as continuous dosing. These results suggest that the use of PARP inhibitors is a promising chemopreventive option.

Complete Protection against Aflatoxin B1-Induced Liver Cancer with a Triterpenoid: DNA Adduct Dosimetry, Molecular Signature, and Genotoxicity Threshold

Abstract: In experimental animals and humans, aflatoxin B1 (AFB1) is a potent hepatic toxin and carcinogen. The synthetic oleanane triterpenoid 1-[2-cyano-3-,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im), a powerful activator of Keap1-Nrf2 signaling, protects against AFB1-induced toxicity and preneoplastic lesion formation (GST-P-positive foci). This study assessed and mechanistically characterized the chemoprotective efficacy of CDDO-Im against AFB1-induced hepatocellular carcinoma (HCC). A lifetime cancer bioassay was undertaken in F344 rats dosed with AFB1 (200 μg/kg rat/day) for four weeks and receiving either vehicle or CDDO-Im (three times weekly), one week before and throughout the exposure period. Weekly, 24-hour urine samples were collected for analysis of AFB1 metabolites. In a subset of rats, livers were analyzed for GST-P foci. The comparative response of a toxicogenomic RNA expression signature for AFB1 was examined. CDDO-Im completely protected (0/20) against AFB1-induced liver cancer compared with a 96% incidence (22/23) observed in the AFB1 group. With CDDO-Im treatment, integrated level of urinary AFB1-N(7)-guanine was significantly reduced (66%) and aflatoxin-N-acetylcysteine, a detoxication product, was consistently elevated (300%) after the first AFB1 dose. In AFB1-treated rats, the hepatic burden of GST-P-positive foci increased substantially (0%-13.8%) over the four weeks, but was largely absent with CDDO-Im intervention. The toxicogenomic RNA expression signature characteristic of AFB1 was absent in the AFB1 + CDDO-Im-treated rats. The remarkable efficacy of CDDO-Im as an anticarcinogen is established even in the face of a significant aflatoxin adduct burden. Consequently, the absence of cancer requires a concept of a threshold for DNA damage for cancer development.

Chemoprevention of head and neck cancer with celecoxib and erlotinib: results of a phase ib and pharmacokinetic study.

Abstract: Epidermal growth factor receptor (EGFR) and COX-2 inhibitors synergistically inhibit head and neck squamous cell carcinoma tumorigenesis in preclinical studies. We conducted a phase I and pharmacokinetic study with the erlotinib and celecoxib combination in patients with advanced premalignant lesions. Thirty-six subjects with oral leukoplakia, mild, moderate, or severe dysplasia, or carcinoma in situ were screened for study participation; 12 consented and received therapy for a median of 5.38 months. Erlotinib was escalated following a standard 3+3 design at 50, 75, and 100 mg orally daily and celecoxib was fixed at 400 mg twice daily for 6 months. Biopsy of lesions and cytobrush of normal mucosa were performed at baseline, 3, 6, and 12 months. Erlotinib pharmacokinetics were analyzed in 10 subjects. The maximum tolerated dose of erlotinib with celecoxib 400 mg BID was 50 mg per day with skin rash being the main observed toxicity. Overall histologic response rate was 63% (complete response, 43%; partial response, 14%; stable disease, 29%; and disease progression, 14%). With median follow-up of 36 months, mean time to progression to higher-grade dysplasia or carcinoma was 25.4 months. Downregulation of EGFR and p-ERK in follow-up biopsies correlated with response to treatment. Larger average erlotinib V/F (approximately 308 L) and CL/F (8.3 L/h) compared with previous studies may be related to relatively large average bodyweights. Average erlotinib t1/2 was 25.6 hours. Encouraging responses to the celecoxib and erlotinib combination correlated with EGFR pathway inhibition. Although erlotinib-related rash was the main limitation to dose escalation, the intervention was well tolerated.

Naproxen Induces Cell-Cycle Arrest and Apoptosis in Human Urinary Bladder Cancer Cell Lines and Chemically Induced Cancers by Targeting PI3K

Abstract: Naproxen ((S)-6-methoxy-α-methyl-2-naphthaleneacetic acid) is a potent nonsteroidal anti-inflammatory drug that inhibits both COX-1 and COX-2 and is widely used as an over-the-counter medication. Naproxen exhibits analgesic, anti-pyretic, and anti-inflammatory activities. Naproxen, as well as other NSAIDS, has been reported to be effective in the prevention of urinary bladder cancer in rodents. However, potential targets other than the COX isozymes have not been reported. We examined potential additional targets in urinary bladder cancer cells and in rat bladder cancers. Computer kinase profiling results suggested that phosphatidylinositol 3-kinase (PI3-K) is a potential target for naproxen. In vitro kinase assay data revealed that naproxen interacts with PI3-K and inhibits its kinase activity. Pull-down binding assay data confirmed that PI3-K directly binds with naproxen in vitro and ex vivo. Western blot data showed that naproxen decreased phosphorylation of Akt, and subsequently decreased Akt signaling in UM-UC-5 and UMUC-14 urinary bladder cancer cells. Furthermore, naproxen suppressed anchorage-independent cell growth and decreased cell viability by targeting PI3-K in both cell lines. Naproxen caused an accumulation of cells at the G1 phase mediated through CDK4, cyclin D1 and p21. Moreover, naproxen induced significant apoptosis, accompanied with increased levels of cleaved caspase 3, caspase 7, and poly (ADP-ribose) polymerase (PARP) in both cell types. Naproxen-induced cell death was mainly due to apoptosis in which a prominent down-regulation of Bcl-2 and up-regulation of Bax were involved. Naproxen also caused apoptosis and inhibited Akt phosphorylation in rat urinary bladder cancers induced by N-butyl-N-(4-hydroxybutyl)-nitrosamine (OH-BBN).

Mammary Cancer Chemoprevention by Withaferin A Is Accompanied by In Vivo Suppression of Self-Renewal of Cancer Stem Cells

Abstract: Current dogma favors elimination of therapy-resistant cancer stem cells (bCSC) for chemoprevention of breast cancer. We showed recently that mammary cancer development in a transgenic mouse model (mouse mammary tumor virus-neu; MMTV-neu) was inhibited significantly upon treatment with withaferin A (WA), a steroidal lactone derived from a medicinal plant. Herein, we demonstrate that the mammary cancer prevention by WA is accompanied by in vivo suppression of bCSC. In vitro mammosphere formation was dose-dependently inhibited by WA treatment in MCF-7 and SUM159 human breast cancer cells. Other markers of bCSC including aldehyde dehydrogenase 1 (ALDH1) activity and CD44high/CD24low/epithelial specific antigen-positive (ESA+) fraction were also decreased significantly in the presence of plasma achievable doses of WA. On the other hand, WA exposure resulted in cell line-specific changes in Oct4, SOX-2, and Nanog mRNA expression. WA administration to MMTV-neu mice (0.1 mg/mouse, three times/week for 28 weeks) resulted in inhibition of mammosphere number and ALDH1 activity in vivo. Mechanistic studies revealed that while urokinase-type plasminogen activator receptor overexpression conferred partial protection against bCSC inhibition by WA, Notch4 was largely dispensable for this response. WA treatment also resulted in sustained (MCF-7) or transient (SUM159) downregulation of Bmi-1 (B cell-specific Moloney murine leukemia virus insertion region-1) protein. Ectopic expression of Bmi-1 conferred partial but significant protection against ALDH1 activity inhibition by WA. Interestingly, WA treatment caused induction of Kruppel-like factor 4 (KLF4) and its knockdown augmented bCSC inhibition by WA. In conclusion, the present study shows in vivo effectiveness of WA against bCSC.

Folate deficiency induces dysfunctional long and short telomeres; both states are associated with hypomethylation and DNA damage in human WIL2-NS cells

Abstract: The essential role of dietary micronutrients for genome stability is well documented, yet the effect of folate deficiency or excess on telomeres is not known Accordingly, human WIL2-NS cells were maintained in medium containing 30, 300, or 3,000 nmol/L folic acid (FA) for 42 days to test the hypothesis that chronic folate deficiency would cause telomere shortening and dysfunction After 14 days, telomere length (TL) in FA-deficient (30 nmol/L) cultures was 26% longer than that of 3,000 nmol/L FA cultures; however, this was followed by rapid telomere attrition over the subsequent 28 days (P trend, P < 00001); both long and short telomere status was positively correlated with biomarkers of chromosome instability (P ≤ 0003) and mitotic dysfunction (P = 001), measured by the cytokinesis-block micronucleus cytome (CBMN-cyt) assay The early increase in TL was associated with FA-deficiency-induced global DNA hypomethylation (P = 005), with an effect size similar to that induced by the DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine Quantitative PCR analysis indicated a negative association between FA concentration and uracil incorporation into telomeric DNA (r = -047, P = 01), suggesting a possible plausible mechanism for uracil as a cause of folate deficiency-induced telomere dysfunction or deletion Peptide nucleic acid-FISH (PNA-FISH) analysis showed that FA deficiency resulted in 60% of micronuclei containing acentric terminal fragments, an observation consistent with the 3-fold increase in terminal deletions (P = 00001) Together, these results demonstrate the impact of folate deficiency on biomarkers of telomere maintenance and integrity, and provide evidence that dysfunctional long telomeres may be as important as critically short telomeres as a cause of chromosomal instability