Navneet Momi

Buccal microRNA dysregulation in lung field carcinogenesis: Gender-specific implications

MicroRNAs (miRNAs) have been shown to be reliable early biomarkers in a variety of cancers including that of lung. We ascertained whether the biomarker potential of miRNAs could be validated in microscopically normal and easily accessible buccal epithelial brushings from cigarette smokers as a consequence of lung cancer linked ‘field carcinogenesis’. We found that compared to neoplasia-free subjects, a panel of 68 miRNAs were upregulated and 3 downregulated in the normal appearing buccal mucosal cells collected from patients harboring lung cancer (n=76). The performance characteristics of selected miRNAs (with ≥1-fold change) were excellent with an average under the receiver operator characteristic curve (AUROC) of >0.80. Several miRNAs also displayed gender specificity between the groups. These results provide the first proof-of-concept scenario in which minimally intrusive cheek brushings could provide an initial screening tool in a large at-risk population.

Higher Order Chromatin Modulator Cohesin SA1 Is an Early Biomarker for Colon Carcinogenesis: Race-Specific Implications.

Alterations in high order chromatin, with concomitant modulation in gene expression, are one of the earliest events in the development of colorectal cancer. Cohesins are a family of proteins that modulate high-order chromatin, although the role in colorectal cancer remains incompletely understood. We, therefore, assessed the role of cohesin SA1 in colorectal cancer biology and as a biomarker focusing in particular on the increased incidence/mortality of colorectal cancer among African-Americans. Immunohistochemistry on tissue arrays revealed dramatically decreased SA1 expression in both adenomas (62%; P = 0.001) and adenocarcinomas (75%; P = 0.0001). RT-PCR performed in endoscopically normal rectal biopsies (n = 78) revealed a profound decrease in SA1 expression in adenoma-harboring patients (field carcinogenesis) compared with those who were neoplasia-free (47%; P = 0.03). From a racial perspective, colorectal cancer tissues from Caucasians had 56% higher SA1 expression than in African-Americans. This was mirrored in field carcinogenesis where healthy Caucasians expressed more SA1 at baseline compared with matched African-American subjects (73%; P = 0.003). However, as a biomarker for colorectal cancer risk, the diagnostic performance as assessed by area under ROC curve was greater in African-Americans (AUROC = 0.724) than in Caucasians (AUROC = 0.585). From a biologic perspective, SA1 modulation of high-order chromatin was demonstrated with both biophotonic (nanocytology) and chromatin accessibility [micrococcal nuclease (MNase)] assays in SA1-knockdown HT29 colorectal cancer cells. The functional consequences were underscored by increased proliferation (WST-1; P = 0.0002, colony formation; P = 0.001) in the SA1-knockdown HT29 cells. These results provide the first evidence indicating a tumor suppressor role of SA1 in early colon carcinogenesis and as a risk stratification biomarker giving potential insights into biologic basis of racial disparities in colorectal cancer. Cancer Prev Res; 9(11); 844–54. ©2016 AACR.

Colonic Mucosal Fatty Acid Synthase as an Early Biomarker for Colorectal Neoplasia: Modulation by Obesity and Gender

Background: We have previously reported that colonic pericryptal microvascular blood flow is augmented in the premalignant colonic epithelium, highlighting the increased metabolic demand of the proliferative epithelium as a marker of field carcinogenesis. However, its molecular basis is unexplored. In this study, we assessed the expression of a regulator of the “lipogenic switch,” fatty acid synthase (FASN), in early colon carcinogenesis for its potential biomarker utility for concurrent neoplasia. Methods: FASN expression (IHC) in the colonic epithelium from azoxymethane and polyposis in rat colon (Pirc) models of colorectal cancer was studied. FASN mRNA expression from endoscopically normal rectal mucosa was evaluated and correlated with colonoscopic findings (pathologic confirmation of neoplasia). Results: FASN expression progressively increased from premalignant to malignant stage in the azoxymethane model (1.9- to 2.5-fold; P < 0.0001) and was also higher in the adenomas compared with adjacent uninvolved mucosa (1.8- to 3.4-fold; P < 0.001) in the Pirc model. Furthermore, FASN was significantly overexpressed in rectal biopsies from patients harboring adenomas compared with those with no adenomas. These effects were accentuated in male (∼2-fold) and obese patients (1.4-fold compared with those with body mass index < 30). Overall, the performance of rectal FASN was excellent (AUROC of 0.81). Conclusions: FASN is altered in the premalignant colonic mucosa and may serve as a marker for colonic neoplasia present elsewhere. The enhanced effects in men and obesity may have implications for identifying patient subgroups at risk for early-onset neoplasia. Impact: These findings support the role of rectal FASN expression as a reliable biomarker of colonic neoplasia. Cancer Epidemiol Biomarkers Prev; 23(11); 2413–21. ©2014 AACR.

Metabolic reprogramming of the premalignant colonic mucosa is an early event in carcinogenesis

Background Colorectal cancer (CRC) is the second leading cause of cancer-related mortality in the United States. There is an increasing need for the identification of biomarkers of pre-malignant and early stage CRC to improve risk-stratification and screening recommendations. In this study, we investigated the possibility of metabolic and mitochondrial reprogramming early in the pre-malignant colorectal field. Methods Rectal biopsies were taken from 81 patients undergoing screening colonoscopy, and gene expression of metabolic and mitochondrial markers were assessed using real time quantitative PCR. Validation studies were performed in two different animal models of colon carcinogenesis: Pirc rats and AOM-treated rats. Results We found evidence of a Warburg effect in the normal-appearing rectal mucosa of patients harboring precancerous lesions elsewhere in the colon compared to control patients, with a significant increase in HIF1a, SLC2A1 (referred to as GLUT1), PKM2, and LDHA. We also found evidence of early mitochondrial changes in the colorectal field of patients harboring pre-cancerous lesions, with significantly increased mitochondrial gene expression of DRP1 (fission), OPA1 (fusion), PGC1-a (biogenesis), UCP2 (uncoupling) and mtND1 (copy number). Similar results were observed in the two different animal models. Conclusions These results demonstrate for the first time evidence of early Warburg-like metabolic changes as well as changes in mitochondrial function, dynamics and mtDNA copy number in endoscopically normal premalignant colorectal mucosal field. These findings provide an opportunity for the development of metabolic biomarkers that could be used for improving screening recommendations and risk-stratification. This also provides a potential target for novel chemopreventive strategies in the pre-malignant colorectal field.

Harnessing novel modalities: field carcinogenesis detection for personalizing prostate cancer management

Department of Internal Medicine, Boston University Medical Center, Boston, MA 02118, USA Biomedical Engineering Department, Northwestern University, Evanston, IL 60208, USA Urology Department, NorthShore University HealthSystems, Evanston, IL 60201, USA *Author for correspondence: Tel.: +1 617 638 8345; hkroy@bu.edu

Abstract B04: Cohesin complex subunit (stromal antigen1): Potential molecular determinant of racial disparities in prostate cancer

Purpose: The overarching goal is to determine the molecular cause of racial disparities in Prostate Cancer (PCa) and exploit its clinical implications. Background: African Americans (AA) have two-thirds higher risk of being diagnosed with PCa with mortality rate twice as high compared to Whites. Evidence supports an earlier transformation to clinically significant PCa in AA. While PCa incidence has declined in the last decade, the racial disparity has not narrowed. Even the improved healthcare, socio-economic/lifestyle factors does not seem to benefit this disparity greatly. Thus, it is evocative that certain biological factors may hold crucial links, therefore necessitating emerging biomarkers for valuable risk stratification. We have recently provided a sensitive/specific optical biomarker as an indicator of field carcinogenesis, segregating patients with indolent vs aggressive PCa. A susceptible genetic background or a field effect is very vital for tumor initiation, allowing accumulation of mutations in neoplastic lesions leading to genomic instability. On these lines, recent studies have demonstrated novel role of cohesion complex genes driving aneuploidy and tumorigenesis. Intriguingly, our investigations in human bio-specimens revealed a consistent downregulation of a putative cohesion complex subunit, Stromal Antigen1 (SA1), in PCa progression. We hypothesized that “SA1 aberrations may serve as an indicator of genomic filed carcinogenesis, providing insights into the biological mechanisms for racial disparities in PCa”. For this, we aimed to characterize SA1 expression in PCa initiation/progression in AA vs Whites, primarily focusing on its relevance with the widely recognized signaling axis in PCa, (pAKT/PI3K), and androgen responsiveness, since both are disproportionately prevalent among AA. Methods: To characterize SA1 levels in PCa field carcinogenesis for AA vs Whites, immunohistochemistry (IHC) for SA1 and PI3K was performed on histologically normal biopsies collected from racially-distinct Gleason6-7 PCa patients undergoing prostactomy. Further, we investigated by IHC the SA1 expression/sub-cellular localization in PTEN (tumor suppressor gene that negatively regulates AKT/PI3K) PCa transgenic mice model. The findings were corroborated in cell-line models using PCa cells (PC3 and DU145) and prostate epithelial cells (RWPE1) by inhibitor studies (for PI3K(LY-294002), nuclear exportin CRM1(LeptomycinB)) via immunofluorescence/immunoblotting. Results: Interestingly, prostate biopsies from AA demonstrated amplified PI3K levels and attenuated SA1 expression with significantly higher cytoplasmic/nuclear ratio compared to Whites, indicating a localization-allied role of SA1. Additionally, SA1 demonstrated altered expression/localization wrt PTEN milieu: nuclear in benign prostatic tissues of PTEN+/+ mice, whereas relatively less and predominantly cytoplasmic in tumor tissues of PTEN-/- mice. Further, PC3 and DU145 PCa cells demonstrated lesser overall SA1 expression with cytoplasmic co-localization with CRM1, whereas in RWPE1 cells SA1 was localized to the nucleus/nuclear membrane. The mechanistic substantiation by antagonist studies revealed significant blocking (~2fold) of CRM1-mediated nuclear-cytoplasmic SA1 shuttling in PC3 cells with LY+LeptomycinB treatment. Moreover, by transiently downregulating SA1, substantial induction of androgen receptor (AR) was noted in AR-negative PC3 cells. Conclusions: Overall, our studies provide a greater role of pAKT/PI3K/PTEN and CRM1 in SA1 mislocalization, facilitating PCa field carcinogenesis, with potential implications in PCa aggressiveness and therapeutic resistance, the two major aspects of poor clinical outcome in AA patients. Our findings may lead to the discovery of novel biomarkers to identify high-risk AA men potentially providing druggable targets. Citation Format: Navneet Momi, Charles B. Brendler, Hemant K. Roy. Cohesin complex subunit (stromal antigen1): Potential molecular determinant of racial disparities in prostate cancer. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr B04.

Sa1909 Fatty Acid Synthase Modulates NSAID Sensitivity via 15-Hydroxyprostaglandin Dehydrogenase (15-PGDH): Implications for Personalizing Chemopreventive Strategies

G A A b st ra ct s for intractable anastomosis stenosis resistant to repeated EBD.(Purpose)The utility of mucosal incision with steroid injection for intractable anastomotic stenosis after gastrectomy is considered.(Material and Methods)The data of a total of 520 consecutive patients who underwent gastrectomy between 2009 and 2014were analyzed retrospectively with a view to determining the incidence of anastomotic stenosis. The period after operation when symptoms of stenosis appeared, methods of gastrectomy and reconstruction of surgery, complications, methods of treatment of stenosis, times of EBD, and the period until symptoms were disappeared were analyzed. We performed EBD only for cases with severe anastomosis stenosis. Mucosal incision was performed by needle knife for thickest part of stricture scar. As steroid injection, 80mg triamcinolone was performed for lack of mucosa after mucosal incision. (Results)Seven patients (1.3%) were developed severe stenosis which needed to be treated by EBD. The median interval between the surgery and detection of stenosis was 1.5 months. The methods of operation and reconstruction after gastrectomy are proximal gastrectomy with esophagogastric anastomosis for 6 patients and with esophago-jejuno anastomosis for 1 patient. 3 patients were added mucosal incision and steroid injection. No serious complication was happened . The median time of EBD until the lumen was kept was 7 times in all patients. The median period after first EBD until the lumen was kept was 10 months in patients conducted only balloon dilatation without mucosal incision, while the median period after mucosal incision was 1 month in patients with mucosal incision(P<0.001).(Conclusion) Mucosal incision with steroid injection was shown to be safety and useful method for severe anastomotic stenosis after gastrectomy. The adaptation of this method is thought to be cases with severe stricture of anastomoses resistant to EBD dilatation, which shows thick scar and restenosis by mucosal defect by EBD. Steroid mucosal injection is thought to be very useful for maintaining the lumen without stricture. Mucosal incision with steroid injection showed to have possibility to improve stenosis for severe stricture resistant of EBD in a short period.

1022 Targeting Fatty Acid Synthase (FASN) As a Modality to Ameliorate Obesity Related Colorectal Cancer (CRC)

Background: Recent research demonstrates association between colonic polyps and insulin resistance(IR). However, it is unclear if this association correlates with polyp neoplastic potential(NP) and whether metabolic features such as non-alcoholic fatty liver disease(NAFLD) or components of the metabolic syndrome(MS) are also associated with colonic neoplasia. Aim: To evaluate the associations between various colonic polyps and metabolic alterations. Methods: Case-control study in consecutive subjects(40-70y), undergoing colonoscopy. Cases with colonic polyps and controls with no polyps were evaluated for metabolic and anthropometric parameters, including ultrasound for NAFLD and liver steatosis quantitation by Hepato-Renal-Index(HRI). We excluded subjects at high risk for colonic neoplasia and severe systemic/metabolic illness. T test, Chi-square test and logistic regression analysis were used. Results: Out of 538 participants (mean age 58.8±6.3, 53.5% men) 269 cases with colonic polyps were compared to 269 controls (Table 1). Dose response association was detected between polyp NP(hyperplastic, non advanced and advanced adenomas), HOMA IR score(P for trend=0.03) and HRI (P for trend=0.01). Polyp risk factors in multivariate analysis, adjusting for age and gender, were: MS(OR=1.92, 95%CI 1.34-2.75, P<0.001), low HDL (OR=1.67, 1.14-2.44, P<0.001), abdominal obesity(OR=1.60, 1.10-2.32, P=0.01), and NAFLD (OR=1.47, 1.04-2.08, P=0.02). In cases of advanced adenoma, number of polyps was positively correlated with fasting serum HOMA IR(r=0.258, P<0.01), waist circumference(r=0.206, P=0.03), HRI(r=0.202, P=0.04), and MS components(r=0.224, P= 0.02). Conclusions: Our initial results strongly suggest that IR, MS and NAFLD predict colonic polyps and their neoplastic potential. This data opens venue for prediction models to improve CRC prevention programs. Comparison of Cases with Colonic Polyps and Controls