P K Roy

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.

Residual Life Estimation of Service Exposed Reheater Tubes in a Boiler of a Thermal Power Plant

The consequence of service failure can be tragic and expensive. There are many cases of engineering disasters resulting in loss of life and property. For boiler components the utmost attention is a must to ensure that such incidents do not take place. Life assessment exercise performed at regular intervals is a means to ensure the absence of such tragic service failure. This paper presents the high temperature tensile and the stress rupture properties of 149084 hours service-exposed reheater tubes made of 2.25Cr-l Mo steels in a 120 MW boiler of a thermal power plant. These were used to estimate the remaining life for safety. Experimentally determined yield strength and ultimate tensile strength as well as estimated 10,000 hours 100,000 hours rupture strength as obtained from experimental data in the temperature range of 520°C to 580°C exhibit a decreasing trend with increasing temperature. The effect of oxide scale deposition on the inner surface of the reheater tubes on the remaining life of the tubes has been discussed. Microstructural study did not reveal any significant degradation in terms of creep cavities, cracks, graphitization etc. In general, analysis of tensile and stress rupture data reveal that the service exposed reheater tubes can remain in service for a length of more than ten years at the operating hoop stress level of 40 MPa /540 °C, provided no localised damage in the form of cracks or dents has developed. It is recommended that a similar health check should be carried out after 50,000 hours of service exposure at 540 °C.

Single Nucleotide Polymorphism Facilitated Down-Regulation of the Cohesin Stromal Antigen-1: Implications for Colorectal Cancer Racial Disparities

The biological underpinnings for racial disparities in colorectal cancer (CRC) incidence remain to be elucidated. We have previously reported that the cohesin SA-1 down-regulation is an early event in colon carcinogenesis which is dramatically accentuated in African-Americans. In order to investigate the mechanism, we evaluated single nucleotide polymorphisms (SNPs) for association with SA-1-related outcomes followed by gene editing of candidate SNP. We observed that rs34149860 SNP was significantly associated with a lower colonic mucosal SA-1 expression and evaluation of public databases showed striking racial discordance. Given that the predicted SNP would alter miR-29b binding site, we used CRISPR knock-in in CRC cells and demonstrated that the SNP but not wild-type had profound alterations in SA-1 expression with miR-29b inhibitor. This is the first demonstration of high-order chromatin regulators as a modulator of racial differences, risk alteration with SNPs and finally specific modulation by microRNAs.

Abstract P3-07-18: Exercise and triple negative breast cancer: Unravelling the anti-neoplastic molecular factors through novel culture method

Background Despite advances to ameliorate breast cancer survival, triple negative breast cancers (TNBCs) attribute to highly disproportionate mortalities due to its aggressiveness and poor therapeutic response (Bao et al., Cancer Medicine 2014). Despite the lack of target-specific drugs, chemotherapy is the mainstay treatment, warranting more efficacious measures against TNBCs. Studies have shown that physical activity intervention reduced breast cancer risk between 20-80% (Monnikohf et. al., Epidemiology 2007) as well as breast cancer related mortality by 34% (Ibrahim et al., Med Onc 2010). However, it is clear that such intervention uptake in the population may not be feasible given the longstanding public health drive to increase physical activity. Therefore it is imperative to identify the molecular factors that might be involved in cancer prevention and therapy with the long term goal of developing a supplement. Due to the recent epidemiological findings on exercise and breast cancer, we wanted to develop a system to comprehensively identify beneficial myokines using a cell culture system. Methods For this study we differentiated C2C12 myoblasts into myotubules. Myotubules were contracted in Krebs Ringer Buffer solution with the C-Pace EP Pacer for 8 hours. Buffer was collected and concentrated using Amicon Ultra-0.5 centrifugal filter tubes to produced an exercise/conditioned medium. To explore the effects of exercise on breast cancer cell lines MCF-7 (ER+) and MDA-MB468 (TNBC line) were treated with conditioned medium for 48 hrs. To explore the effects of exercise and chemotherapeutic efficacy MDA-MB468 cells were treated with doxorubicin, conditioned medium or both for 48 hrs. Protein was isolated and processed for immunoblot analysis. Cell cycle markers p21, pRb, cyclin D1, PCNA as well as apoptotic marker cPARP were assessed to reveal the effects treatment. Results Treatment of conditioned medium in MCF-7 revealed marked changes in both p21 (92% increase, p=0.05) and pRb protein expression (62% decrease, p Conclusions We have developed a novel system that may enable, for the first time, mechanistic studies to elucidate the role of skeletal muscle/exercise in breast cancer prevention and chemotherapy. Our data indicates a secreted factor(s) from skeletal muscles that plays a role in anti-proliferative and pro-apoptotic effects, which are the hallmark of exercise9s anti-neoplastic properties. Studies are ongoing to further understand, characterize and isolate this factor(s) for therapeutic purposes. Given the limited chemotherapeutic options and heterogeneity in TNBC, our exercise culture system sheds a promising light on novel drug development and chemo-sensitization. Citation Format: Dela Cruz MA, Roy P, Chowdhury S, Chan S, Roy HK. Exercise and triple negative breast cancer: Unravelling the anti-neoplastic molecular factors through novel culture method [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-07-18.

Life Prediction of Service Exposed Tubes in a Boiler of a Thermal Power Plant

Boiler tubes in power plants have finite life because of prolonged exposure to high temperature, stress and aggressive environment. Platen superheater and reheater tubes, made of 2.25Cr-l Mo steels, service-exposed for 148,900 hours in a 120 MW boiler of a thermal power plant, underwent detailed metallurgical assessment to analyze their remaining safety life. The investigation included hot tensile, hardness measurement, dimensional measurement, microscopy and a few accelerated creep tests. Analysis revealed that experimentally determined yield strength and ultimate tensile strength, as well as estimated 10,000100,000 hours rupture strength as obtained from experimental data in the temperature range of 520°C to 580°C, exhibited a decreasing trend with increasing temperature. Microstructural study did not reveal any significant degradation in terms of creep cavities, cracks, graphitization etc. In general, analysis of tensile and stress rupture data revealed that, although there was degradation of the tubes due to the prolonged service exposure in terms of the ultimate tensile strength values, stress rupture plots showed that the service exposed superheater and reheater tubes could remain in service for a length of more than ten years at the operating hoop stress level 40 MPa / 540 °C, provided that no localised damage in the form of cracks or dents developed. It is recommended that a similar health check should be carried out after 50,000 hours of service exposure at 540 °C. Key w o r d s : Service exposed, superheater, reheater, boilers, stress rupture test, tensile properties, residual life.