Carcinogenesis In Animal Models Research Articles

Food Toxicology and Food Safety: Report of the 3rd International Electronic Conference on Foods: Food, Microbiome, and Health-A Celebration of the 10th Anniversary of Foods' Impact on Our Wellbeing.

The purpose of the conference session summarized in this article was to bring together international experts on food toxicology and food safety and share the current scientific knowledge on these topics. The presentations covered a wide range of interdisciplinary issues, including (i) the impact of diet on body weight and health outcomes including results from animal models of carcinogenesis, (ii) methods for microbial oil extraction, (iii) food processing and its impact on food safety and health, (iv) novel compounds to avoid mycotoxin contamination of agricultural products, and (v) the safety of cannabidiol in food supplements based on Cannabis sativa extracts. Some of the conclusions of the presentations included that correct food choices may impact on the risk of non-communicable diseases such as cancer, that food processing may have an influence on health, by either reducing or increasing risks, and that research regarding novel compounds is important, which may have preventive but also detrimental effects on health.

Treatment of Human HeLa Cells with Black Raspberry Extracts Enhances the Removal of DNA Lesions by the Nucleotide Excision Repair Mechanism.

As demonstrated by us earlier and by other researchers, a diet containing freeze-dried black raspberries (BRB) inhibits DNA damage and carcinogenesis in animal models. We tested the hypothesis that the inhibition of DNA damage by BRB is due, in part, to the enhancement of DNA repair capacity evaluated in the human HeLa cell extract system, an established in vitro system for the assessment of cellular DNA repair activity. The pre-treatment of intact HeLa cells with BRB extracts (BRBE) enhances the nucleotide excision repair (NER) of a bulky deoxyguanosine adduct derived from the polycyclic aromatic carcinogen benzo[a]pyrene (BP-dG) by ~24%. The NER activity of an oxidatively-derived non-bulky DNA lesion, guanidinohydantoin (Gh), is also enhanced by ~24%, while its base excision repair activity is enhanced by only ~6%. Western Blot experiments indicate that the expression of selected, NER factors is also increased by BRBE treatment by ~73% (XPA), ~55% (XPB), while its effects on XPD was modest (<14%). These results demonstrate that BRBE significantly enhances the NER yields of a bulky and a non-bulky DNA lesion, and that this effect is correlated with an enhancement of expression of the critically important NER factor XPA and the helicase XPB, but not the helicase XPD.

Current Novel Concept of Carcinogenesis to Combat Oral Cancer

One of the greatest public health threats around the world is oral cancer. Field cancerization and carcinogenesis are two steps in the multistep and multifocal tobacco-related process of oral cancer development. The rationale for molecularly targeted oral cancer prevention at the molecular level is promising. Aneuploidy and allelic imbalance are two biomarkers of genomic instability that can be used to estimate cancer risk of oral premalignancies. Understanding the biology of oral carcinogenesis can help us make significant advances in pharmacogenomics, cancer risk assessment, identification of high-risk patients, monitoring of preventive measures, and cancer diagnosis in patients. In addition, research on appropriate animal models of carcinogenesis will lead to the development of new chemopreventive drugs against oral malignancies based on molecular signalling pathways and targets. Novel approaches, such as interventions with molecularly targeted agents and drug combinations in high-risk oral patients, are undoubtedly needed to reduce the devastating global consequences of oral malignancy.

Comparison of the effects of aqueous extract of Sida cordifolia L. and 5-fluorouracil in colon carcinogenesis induced by 1,2- dimethylhydrazine on Wistar rats

Search for new therapeutic agents and alternative strategies for chemoprevention of colorectal cancer is needed to reduce morbidity and mortality resulting from this disease. This study aimed to compare the effect of aqueous extract of Sida cordifolia L. and 5- fluorouracil (5-FU) on colon carcinogenesis induced by 1,2- dimethylhydrazine (1,2-DMH). The extract reduced the frequency of aberrant crypts to regarding the positive control, but there was no significant difference among the positive control animals, those who received the extract and those receiving standard anticancer drug. Thus, the aqueous extract of Sida cordifolia L. 800 mg/kg showed no statistical impact on carcinogenesis in animal models, but showed a significant anti-inflammatory effect on the colon mucosa.

Fish Consumption and Colorectal Cancer Risk: Meta-Analysis of Prospective Epidemiological Studies and Review of Evidence from Animal Studies.

Simple SummaryWe meta-analyzed prospective epidemiological studies reporting on the association between fish consumption and colorectal cancer (CRC) risk among humans and reviewed preclinical studies that examined the link between fish components and colorectal carcinogenesis in animals. By pooling results from 25 studies (encompassing over 25,000 CRC cases) published up to November 2020, we found convincing evidence that increased fish consumption may protect from CRC development among humans. The review of animal studies allowed identifying several biological mechanisms able to explain the associations that have emerged in human populations. Dietary recommendations for cancer prevention should incorporate the evidence from this literature review and meta-analysis.Background: Epidemiological studies on the association between fish consumption and colorectal cancer (CRC) risk have yielded inconsistent results, despite evidence from preclinical studies that long-chain ω-3 polyunsaturated fatty acids inhibit colorectal carcinogenesis. We conducted a meta-analysis of prospective epidemiological studies investigating the association between fish consumption and CRC risk among humans and reviewed studies examining the link between fish components and colorectal carcinogenesis in animal models. Methods: We included studies published until November 2020. We calculated the summary risk ratio (SRR) and 95% confidence intervals (CI) through random effects meta-analysis models in order to summarize evidence from studies among humans. Results: Twenty-five prospective epidemiological studies encompassing 25,777 CRC cases were included. Individuals in the highest (vs. lowest) category of fish consumption had a significantly reduced risk of CRC (SRR 0.94, 95%CI 0.89–0.99). In dose–response meta-analysis, a 50-g increment in the daily consumption of fish was associated with a statistically significant 4% reduction in CRC risk (SRR 0.96, 95%CI 0.92–0.99). Preclinical studies (n = 25) identified multiple mechanisms of action of fish and fish components on colorectal carcinogenesis. Conclusions: Dietary recommendations for cancer prevention should take into account the evidence from epidemiological and preclinical studies that increasing fish consumption may be effective in preventing CRC.

Fucoxanthin Prevents Pancreatic Tumorigenesis in C57BL/6J Mice That Received Allogenic and Orthotopic Transplants of Cancer Cells.

Fucoxanthin (Fx) is a marine carotenoid with anti-inflammatory and anti-cancer properties in various animal models of carcinogenesis. However, there is currently no information on the effects of Fx in animal models of pancreatic cancer. We investigated the chemopreventive effects of Fx in C57BL/6J mice that received allogenic and orthotopic transplantations of cancer cells (KMPC44) derived from a pancreatic cancer murine model (Ptf1aCre/+; LSL-krasG12D/+). Using microarray, immunofluorescence, western blot, and siRNA analyses, alterations in cancer-related genes and protein expression were evaluated in pancreatic tumors of Fx-administered mice. Fx administration prevented the adenocarcinoma (ADC) development of pancreatic and parietal peritoneum tissues in a pancreatic cancer murine model, but not the incidence of ADC. Gene and protein expressions showed that the suppression of chemokine (C-C motif) ligand 21 (CCL21)/chemokine receptor 7 (CCR7) axis, its downstream of Rho A, B- and T-lymphocyte attenuator (BTLA), N-cadherin, αSMA, pFAK(Tyr397), and pPaxillin(Tyr31) were significantly suppressed in the pancreatic tumors of mice treated with Fx. In addition, Ccr7 knockdown significantly attenuated the growth of KMPC44 cells. These results suggest that Fx is a promising candidate for pancreatic cancer chemoprevention that mediates the suppression of the CCL21/CCR7 axis, BTLA, tumor microenvironment, epithelial mesenchymal transition, and adhesion.

Hi-C scaffolded short- and long-read genome assemblies of the California sea lion are broadly consistent for syntenic inference across 45 million years of evolution.

With the advent of chromatin-interaction maps, chromosome-level genome assemblies have become a reality for a wide range of organisms. Scaffolding quality is, however, difficult to judge. To explore this gap, we generated multiple chromosome-scale genome assemblies of an emerging wild animal model for carcinogenesis, the California sea lion (Zalophus californianus). Short-read assemblies were scaffolded with two independent chromatin interaction mapping data sets (Hi-C and Chicago), and long-read assemblies with three data types (Hi-C, optical maps and 10X linked reads) following the "Vertebrate Genomes Project (VGP)" pipeline. In both approaches, 18major scaffolds recovered the karyotype (2n=36), with scaffold N50s of 138 and 147Mb, respectively. Synteny relationships at the chromosome level with other pinniped genomes (2n=32-36), ferret (2n=34), red panda (2n=36) and domestic dog (2n=78) were consistent across approaches and recovered known fissions and fusions. Comparative chromosome painting and multicolour chromosome tiling with a panel of 264genome-integrated single-locus canine bacterial artificial chromosome probes provided independent evaluation of genome organization. Broad-scale discrepancies between the approaches were observed within chromosomes, most commonly in translocations centred around centromeres and telomeres, which were better resolved in the VGP assembly. Genomic and cytological approaches agreed on near-perfect synteny of the X chromosome, and in combination allowed detailed investigation of autosomal rearrangements between dog and sea lion. This study presents high-quality genomes of an emerging cancer model and highlights that even highly fragmented short-read assemblies scaffolded with Hi-C can yield reliable chromosome-level scaffolds suitable for comparative genomic analyses.

Probiotic Aspergillus oryzae produces anti-tumor mediator and exerts anti-tumor effects in pancreatic cancer through the p38 MAPK signaling pathway

Intake of probiotics or fermented food produced by some probiotic bacteria is believed to exert anti-tumor functions in various cancers, including pancreatic cancer, because several studies have demonstrated the anti-tumor effects of probiotic bacteria in vitro and in vivo in animal carcinogenesis models. However, the mechanisms underlying the anticancer effects of probiotics on pancreatic cancer have not been clarified. In this study, we assessed the anti-tumor effects of probiotic bacteria against pancreatic cancer cells. Among the known probiotic bacteria, Aspergillus oryzae exhibited a strong pancreatic tumor suppression effect. The culture supernatant of A. oryzae was separated by HPLC. Heptelidic acid was identified as an anti-tumor molecule derived from A. oryzae by LC–MS and NMR analysis. The anti-tumor effect of heptelidic acid was exhibited in vitro and in vivo in a xenograft model of pancreatic cancer cells. The anti-tumor effect of heptelidic acid was exerted by the p38 MAPK signaling pathway. Heptelidic acid traverses the intestinal mucosa and exerts anti-tumor effects on pancreatic cancer cells. This is a novel anti-tumor mechanism induced by beneficial bacteria against pancreatic cancer in which bacterial molecules pass through the intestinal tract, reach the extra-intestinal organs, and then induce apoptosis via an inducible signaling pathway.

Plasma, Prostate and Urine Levels of Tocopherols and Metabolites in Men after Supplementation with a γ-Tocopherol-Rich Vitamin E Mixture

The vitamin E forms γ- and δ-tocopherols (T) inhibit carcinogenesis in animal models; nevertheless, their cancer preventive activities in humans are uncertain. As an initial step to address this issue, we conducted a pilot phase 0 trial to determine the levels of tocopherols and their metabolites in prostate cancer patients undergoing radical prostatectomy. The patients were randomized to no supplementation or two capsules of a γ-T-rich vitamin E mixture daily for 7 or 14 day prior to prostatectomy. Blood and urine samples were collected before supplementation and on the day of surgery, along with prostate tissue, for analysis of tocopherols and their metabolites. Estimated blood loss during surgery was not significantly different across treatment arms and there were no reported adverse events. Prostate tissue levels of γ-T and δ-T were increased after 14 day of supplementation. Their side-chain degradation metabolites (CEHCs and CMBHCs) were significantly elevated in plasma, prostate and urine samples after supplementation for 7 or 14 day. In conclusion, supplementation with γ-T-rich vitamin E increased the prostate levels of γ-T and δ-T. The use of pure γ-T, δ-T or tocopherol mixtures with higher ratio of γ-T or δ-T to α-T is recommended for future studies.

A Review on Luteolin: A Versatile Flavonoid

Luteolin (3′,4′,5,7-tetrahydroxy flavone) is a flavonoid belonging to the subgroup of flavone, it is a naturally occurring compound in its glycosylated form, and exists in many types of plants including fruits, vegetables, and medicinal herbs. It has been suggested in preclinical studies that flavones possesses a variety of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial and anticancer activities. Like other flavones, it has been seen that plants rich in luteolin have been used in traditional medicine for treating various diseases. The purpose of this article is to systematically explain different aspects of luteolin with respect to its biosynthesis, total chemical synthesis, structure activity relationship and the aspects of the structure making it an effective pharmacological agent, it’s pharmacokinetic aspects and its pharmacological and therapeutic activity on the human body. Here pharmacological effects of luteolin is an important aspect because of its ability to inhibit angiogenesis, to induce apoptosis, to prevent carcinogenesis in animal models thereby showing chemo-preventive and chemotherapeutic potential, show antioxidant activity, anti-inflammatory activity, anti-allergic effect, antispasmodic activity, anti-ulcer, anti-ageing , whitening activity , activity to mitigate psoriasis as well as have prominent neuroprotective effects. Keywords: Anti-allergic, anti-inflammatory, antioxidant, biosynthesis, chemoprotective, Luteolin, neuroprotective, pharmacokinetics, structure activity relationship Cite this Article Aditi Ashish Datta, Abhishek Ashish Datta. A Review on Luteolin: A Versatile Flavonoid. Research & Reviews: A Journal of Drug Formulation, Development and Production . 2020; 7(2): 33–61p.

Evidence for immortality and autonomy in animal cancer models is often not provided, which causes confusion on key issues of cancer biology.

Modern research into carcinogenesis has undergone three phases. Surgeons and pathologists started the first phase roughly 250 years ago, establishing morphological traits of tumors for pathologic diagnosis, and setting immortality and autonomy as indispensable criteria for neoplasms. A century ago, medical doctors, biologists and chemists started to enhance “experimental cancer research” by establishing many animal models of chemical-induced carcinogenesis for studies of cellular mechanisms. In this second phase, the two-hit theory and stepwise carcinogenesis of “initiation-promotion” or “initiation-promotion-progression” were established, with an illustrious finding that outgrowths induced in animals depend on the inducers, and thus are not authentically neoplastic, until late stages. The last 40 years are the third incarnation, molecular biologists have gradually dominated the carcinogenesis research fraternity and have established numerous genetically-modified animal models of carcinogenesis. However, evidence has not been provided for immortality and autonomy of the lesions from most of these models. Probably, many lesions had already been collected from animals for analyses of molecular mechanisms of “cancer” before the lesions became autonomous. We herein review the monumental work of many predecessors to reinforce that evidence for immortality and autonomy is essential for confirming a neoplastic nature. We extrapolate that immortality and autonomy are established early during sporadic human carcinogenesis, unlike the late establishment in most animal models. It is imperative to resume many forerunners' work by determining the genetic bases for initiation, promotion and progression, the genetic bases for immortality and autonomy, and which animal models are, in fact, good for identifying such genetic bases.

Abstract 623: Iron intake, oxidative stress-related genes, and breast cancer risk

Abstract Background: Iron has been shown to enhance breast carcinogenesis in animal models through generation of oxidative stress, although epidemiological evidence of the association between iron intake and breast cancer risk remains inconclusive. This study investigated associations between different types of iron intake and breast cancer risk, and whether these associations were modified by genetic polymorphisms in antioxidant enzymes, including manganese superoxide dismutase (MnSOD) and glutathione S-transferases M1 (GSTM1) and T1 (GSTT1). Methods: A population-based case-control study in Ontario, Canada recruited 3,030 breast cancer cases identified from the Ontario Cancer Registry and 3,402 controls from random digit dialing. Iron intake from foods and supplements was assessed using a 178-item food frequency questionnaire. Multivariable logistic regression analyses were used to evaluate associations between breast cancer risk and intakes of dietary, supplemental, and total (dietary plus supplemental) iron, among all women and stratified by menopausal status. Associations were also examined by hormone receptor [estrogen receptor (ER)/progesterone receptor (PR)] tumor subtype. Among women providing saliva (DNA) samples (1,696 cases and 1,761 controls), interactions between iron intake and genetic polymorphisms were assessed using the likelihood ratio test. Results: Among all women, intakes of dietary, supplemental, and total iron were not associated with breast cancer risk, overall or by tumor subtype. Among premenopausal women, there was an increase in breast cancer risk for the ER–PR– subtype associated with higher intakes (highest vs. lowest quintile) of dietary [odds ratio (OR) = 1.4; 95% confidence interval (CI): 0.9–2.4] and total (OR = 1.8; 95% CI: 1.1–2.9) iron (P for trend < 0.05). Among postmenopausal women, supplemental iron intake (>18 vs. 0 mg/day) was associated with reduced breast cancer risk (OR = 0.7; 95% CI: 0.5–0.9), with similar associations across tumor subtypes. Associations of dietary and total iron intake with overall breast cancer risk were modified by GSTT1 and/or GSTM1/T1 combined genotypes (P for interaction < 0.05). For example, among women with deletions in both GSTM1 and GSTT1 loci, higher dietary iron intake was associated with increased breast cancer risk (OR = 2.1; 95% CI: 1.1–4.2), whereas null or inverse associations were found among women with other GSTM1/T1 genotypes. Conclusions: Results from this study suggest that higher dietary and total iron intake may be associated with increased risk of ER–PR– breast cancer among premenopausal women, whereas higher supplemental iron intake may be associated with reduced postmenopausal breast cancer risk. In addition, associations between iron intake and breast cancer risk may be modified by polymorphisms in oxidative stress-related genes. Our ongoing work will investigate heme and non-heme iron intake in relation to breast cancer risk. Citation Format: Vicky C. Chang, Michelle Cotterchio, Susan J. Bondy, Joanne Kotsopoulos. Iron intake, oxidative stress-related genes, and breast cancer risk [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 623.

Temporal induction of intestinal epithelial hypoxia-inducible factor-2α is sufficient to drive colitis.

Hypoxia is a notable feature of inflammatory bowel disease and chronic induction of hypoxia-inducible factor (HIF)-1α and HIF-2α (endothelial PAS domain protein 1, EPAS1) play important, but opposing, roles in its pathogenesis. While activation of HIF-1α decreases intestinal inflammation and is beneficial in colitis, activation of HIF-2α exacerbates colitis and increases colon carcinogenesis in animal models, primarily due to the role of epithelial HIF-2α in mounting a potent inflammatory response. Previous work from our laboratory showed that mice overexpressing intestinal epithelial HIF-2α led to massive intestinal inflammation and decreased survival. As oxygen homeostasis and HIFs are critical in embryonic development, it is not clear whether the observed intestinal inflammatory response was secondary to developmental defects. To address this question, the present study used a mouse model to temporally modulate expression of intestinal epithelial HIF-2α to assess its role in mediating inflammatory response. Remarkably, activation of HIF-2α in intestinal epithelial cells in adult mice increased expression of proinflammatory mediators; however, no decrease in survival was observed. Furthermore, in an acute model of colitis, activation of HIF-2α was sufficient to exacerbate colitis. These data confirm our previous finding that epithelial HIF-2α mediates inflammatory response and demonstrates that activation of HIF-2α is sufficient to exacerbate colitis.NEW & NOTEWORTHY Inflammatory bowel disease (IBD) is a chronic relapsing inflammatory disease of the intestinal tract. Hypoxia and activation of its downstream transcription factors hypoxia-inducible factor (HIF)-1α and HIF-2α are notable features of IBD. HIF-1α has well-characterized protective roles in IBD; however, the role of HIF-2α has been less studied. Using novel HIF-2α mouse models, we show that activation of HIF-2α in intestinal epithelial cells is sufficient to exacerbate colitis.

Nobiletin and Derivatives: Functional Compounds from Citrus Fruit Peel for Colon Cancer Chemoprevention.

The search for effective methods of cancer treatment and prevention has been a continuous effort since the disease was discovered. Recently, there has been increasing interest in exploring plants and fruits for molecules that may have potential as either adjuvants or as chemopreventive agents against cancer. One of the promising compounds under extensive research is nobiletin (NOB), a polymethoxyflavone (PMF) extracted exclusively from citrus peel. Not only does nobiletin itself exhibit anti-cancer properties, but its derivatives are also promising chemopreventive agents; examples of derivatives with anti-cancer activity include 3′-demethylnobiletin (3′-DMN), 4′-demethylnobiletin (4′-DMN), 3′,4′-didemethylnobiletin (3′,4′-DMN) and 5-demethylnobiletin (5-DMN). In vitro studies have demonstrated differential efficacies and mechanisms of NOB and its derivatives in inhibiting and killing of colon cancer cells. The chemopreventive potential of NOB has also been well demonstrated in several in vivo colon carcinogenesis animal models. NOB and its derivatives target multiple pathways in cancer progression and inhibit several of the hallmark features of colorectal cancer (CRC) pathophysiology, including arresting the cell cycle, inhibiting cell proliferation, inducing apoptosis, preventing tumour formation, reducing inflammatory effects and limiting angiogenesis. However, these substances have low oral bioavailability that limits their clinical utility, hence there have been numerous efforts exploring better drug delivery strategies for NOB and these are part of this review. We also reviewed data related to patents involving NOB to illustrate the extensiveness of each research area and its direction of commercialisation. Furthermore, this review also provides suggested directions for future research to advance NOB as the next promising candidate in CRC chemoprevention.

Clinical uses of melatonin: evaluation of human trials on cancer treatment.

Melatonin is a molecule with numerous properties, which are applicable to the treatment of different types of cancers. Experimental in vitro and in vivo studies conducted with human cancer cells or animal models of carcinogenesis, have shown that melatonin enhances apoptosis and inhibits cell proliferation of several human cancer cells, reduces tumor growth rate and its metastases, reduces the side effects of chemotherapy and radiotherapy, decreases the resistance to standard cancer treatments, and potentiates the therapeutic effects of other conventional therapies. These satisfactory results obtained from “bench” need to be studied in clinical trials to verify whether they are applicable to “bedside”. In this article we review the clinical trials carried out in the last 25 years which are focused on the therapeutic use of melatonin in cancer treatment. We conclude that melatonin is an effective adjuvant drug to practically any conventional cancer therapy since it is capable of improving the quality of life of patients, by normalizing sleep and alleviating general symptoms associated with tumor disease and treatment such as pain, asthenia, anorexia, etc. In the particular case of hormone-dependent breast cancer, melatonin's antiestrogenic properties make this indoleamine ideally suited for use in association with other synthetic anti-estrogen agents, as melatonin increases their efficacy while reducing their undesirable effects. Furthermore, melatonin could be an appropriate co-treatment for preventive treatment of breast cancer in people with elevated risk for this kind of neoplasia.

Iron intake, body iron status, and risk of breast cancer: a systematic review and meta-analysis

BackgroundIron has been shown to promote breast carcinogenesis in animal models through generation of oxidative stress and interaction with estrogen. Heme iron, which is found exclusively in animal-sourced foods, is suggested to have a more detrimental effect. Epidemiological evidence of the association between iron and breast cancer risk remains inconclusive and has not been comprehensively summarized. This systematic review and meta-analysis evaluated associations between both iron intake and body iron status and breast cancer risk.MethodsFour electronic databases (MEDLINE, EMBASE, CINAHL, and Scopus) were searched up to December 2018 for studies assessing iron intake and/or biomarkers of iron status in relation to breast cancer risk. Using random-effects meta-analyses, pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated comparing the highest vs. lowest category of each iron measure. Dose-response meta-analyses were also performed to investigate linear and nonlinear associations.ResultsA total of 27 studies were included in the review, of which 23 were eligible for meta-analysis of one or more iron intake/status measures. Comparing the highest vs. lowest category, heme iron intake was significantly associated with increased breast cancer risk, with a pooled RR of 1.12 (95% CI: 1.04–1.22), whereas no associations were found for dietary (1.01, 95% CI: 0.89–1.15), supplemental (1.02, 95% CI: 0.91–1.13), or total (0.97, 95% CI: 0.82–1.14) iron intake. Associations of iron status indicators with breast cancer risk were generally in the positive direction; however, a significant pooled RR was found only for serum/plasma levels (highest vs. lowest) of iron (1.22, 95% CI: 1.01–1.47), but not for ferritin (1.13, 95% CI: 0.78–1.62), transferrin saturation (1.16, 95% CI: 0.91–1.47), or total iron-binding capacity (1.10, 95% CI: 0.97–1.25). In addition, a nonlinear dose-response was observed for heme iron intake and serum iron (both Pnonlinearity < 0.05).ConclusionsHeme iron intake and serum iron levels may be positively associated with breast cancer risk. Although associations were modest, these findings may have public health implications given the widespread consumption of (heme) iron-rich foods. In light of methodological and research gaps identified, further research is warranted to better elucidate the relationship between iron and breast cancer risk.

Abstract 5884: 4EBP1 is a tumor suppressor gene unleashed by mTOR inhibition in head and neck squamous cell carcinoma

Abstract Persistent aberrant activation of the PI3K/AKT/mTOR signaling pathway occurs in over 80% of head and neck squamous cell carcinomas (HNSCC). In prior studies we have shown that mTOR regulates proliferation, angiogenesis and apoptosis, thus playing an essential role in HNSCC initiation and progression. The frequent over-reliance on this signaling circuit for HNSCC growth may in turn represent a cancer vulnerability that can be exploited therapeutically. Indeed, we have shown that mTOR inhibitors (mTORi) promote tumor regression in multiple genetically defined and chemically induced carcinogenesis animal models, and encouraging results have been recently obtained using mTORi in HNSCC in the clinic. However, the complexity of genomic alterations in HNSCC may facilitate the emergence of drug resistance, especially in cases with patients who may receive multiple rounds of chemotherapy and/or radiation. Understanding the precise molecular processes by which mTOR acts in HNSCC may help predict intrinsic resistance mechanisms and select patients who may benefit the most from the administration of mTORi. Here, we focused on EIF4EBP1 (4EBP1), a direct target of mTOR that serves as key effector for protein synthesis. Remarkably, we found a negative correlation between 4EBP1 gene copy number loss and disease-free survival (p&amp;lt;0.001) and overall survival (p&amp;lt;0.01) in the HNSCC TCGA database (n=181). Furthermore, IHC analysis of 4EBP1 protein expression revealed that 16.3% of HNSCC cases analyzed (n=49) lack 4EBP1, with progressive protein loss in advanced cases. Aligned with a tumor-suppressive role, 4ebp1-knockout mice formed larger and more HNSCC lesions (p&amp;lt;0.001) in 4NQO oral carcinogenesis models. We engineered a mutant 4EBP1 that cannot be phosphorylated by mTOR (4EBP1-mut), resembling de-phospho-4EBP1, and generated HNSCC cells expressing this mutant in a tetracycline-inducible fashion. Protein-protein interactions and assembly of the translational complex were analyzed using 7-methyl GTP pull-down and co-IP assays. Expression of 4EBP1-mut disrupted the function of the translation initiation complex and was sufficient to prevent tumor growth in HNSCC xenograft models. Similarly, mTORi induced the accumulation of dephosphorylated endogenous wild-type 4EBP1 and resulted in HNSCC xenograft regression. Remarkably, CRISPR-CAS9-mediated knockout of 4EBP1 in HNSCC cells caused insensitivity to mTORi in vitro and in vivo. Overall, our findings suggest that 4EBP1 needs to be persistently repressed by mTOR phosphorylation in HNSCC and that mTORi may unleash 4EBP1's tumor-suppressive activity, thereby reducing the translation of growth-promoting and cancer cell stemness-related proteins. In turn, 4EBP1 gene and protein loss may underlie mTORi resistance, supporting that 4EBP1 expression and phosphorylation status may represent a mechanistic biomarker of mTORi sensitivity in HNSCC patients. Citation Format: Zhiyong Wang, Daniel Martin, Lynn Vitale-Cross, Xiaodong Feng, Alfredo A. Molinolo, Michael M. Allevato, Victoria H. Wu, Mara Gilardi, Hao Xu, Qianming Chen, J.Silvio Gutkind. 4EBP1 is a tumor suppressor gene unleashed by mTOR inhibition in head and neck squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5884.

BAG3 Protein Is Involved in Endothelial Cell Response to Phenethyl Isothiocyanate.

Phenethyl isothiocyanate (PEITC), a cruciferous vegetable-derived compound, is a versatile cancer chemopreventive agent that displays the ability to inhibit tumor growth during initiation, promotion, and progression phases in several animal models of carcinogenesis. In this report, we dissect the cellular events induced by noncytotoxic concentrations of PEITC in human umbilical vein endothelial cells (HUVECs). In the early phase, PEITC treatment elicited cells' morphological changes that comprise reduction in cell volume and modification of actin organization concomitantly with a rapid activation of the PI3K/Akt pathway. Downstream to PI3K, PEITC also induces the activity of Rac1 and activation of c-Jun N-terminal kinase (JNK), well-known regulators of actin cytoskeleton dynamics. Interestingly, PEITC modifications of the actin cytoskeleton were abrogated by pretreatment with JNK inhibitor, SP600125. JNK signaling led also to the activation of the c-Jun transcription factor, which is involved in the upregulation of several genes; among them is the BAG3 protein. This protein, a member of the BAG family of heat shock protein (Hsp) 70 cochaperones, is able to sustain survival in different tumor cell lines and neoangiogenesis by directly regulating the endothelial cell cycle. Furthermore, BAG3 is involved in maintaining actin folding. Our findings indicate that BAG3 protein expression is induced in endothelial cells upon exposure to a noncytotoxic concentration of PEITC and its expression is requested for the recovery of normal cell size and morphology after the stressful stimuli. This assigns an additional role for BAG3 protein in the endothelial cells after a stress event.

Preventive effect of genistein on AOM/DSS-induced colonic neoplasm by modulating the PI3K/AKT/FOXO3 signaling pathway in mice fed a high-fat diet

Colon cancer is one of the most prevalent malignancies in the world. The incidence of colon cancer is on the rise, which seriously affects people's physical and mental health. Genistein, the predominant isoflavone found in soy products, has been shown to inhibit carcinogenesis in animal models. However, the molecular mechanisms involved in genistein preventing carcinogenesis are still uncharacterized. This study was aimed to evaluate the preventive effect of genistein-rich diet on azoxymethane/dextran sulfate sodium (AOM/DSS) induced colon cancer in high-fat mice. Contrasted with control group, the addition of genistein can ward off colon cancer. The expression of COX-2, TNF-α and FRAT1 mRNA has decreased in genistein-treated group. Furthermore, genistein-rich diet has inhibited the viability of colon cancer via regulating the expression of PI3K, FOXO3 and AKT. It has been suggested that genistein prevent the colonic neoplasms growth by modulating the PI3K/FOXO3/AKT signaling pathway in mice fed with a high-fat diet.

Intense Pulsed Light: Friend or Foe? Molecular Evidence to Clarify Doubts.

Intense pulsed light (IPL) has been extensively applied in the field of dermatology and aesthetics; however, the long-term consequences of its use are poorly unknown, and to the best of our knowledge there is no study on the effect of IPL in neoplastic lesions. In order to better understand the molecular mechanisms underlying IPL application in the skin, we used an animal model of carcinogenesis obtained by chemical induction with 12-dimethylbenz(a)anthracene (DMBA) and 12-O-tetradecanoylphorbol-13-acetate (TPA). Institute of Cancer Research (ICR) mice were administered DMBA and/or TPA and treated with IPL. Skin was evaluated by histopathology and 2DE-blot-MS/MS analysis. Our data evidenced an inflammatory response and a metabolic remodeling of skin towards a glycolytic phenotype after chronic exposure to IPL, which was accomplished by increased oxidative stress and susceptibility to apoptosis. These alterations induced by IPL were more notorious in the DMBA sensitized skin. Keratins and metabolic proteins seem to be the more susceptible to oxidative modifications that might result in loss of function, contributing for the histological changes observed in treated skin. Data highlight the deleterious impact of IPL on skin phenotype, which justifies the need for more experimental studies in order to increase our understanding of the IPL long-term safety.