CBR Research Grants
Project Summaries—2006
2006 |
||||||||||||||||
2006Statins as chemopreventative and combinational therapeutic agents in colon cancer Statins [3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors] are cholesterol lowering drugs that have revolutionized the treatment of cardiovascular and cerebrovascular disease. Statins demonstrate many anti-cancer properties. Epidemiological and preclinical data has shown that statins could potentially play a pivotal role as chemopreventive agents in colorectal cancer. The APC [Adenomatous Polyposis coli] gene is a tumor suppressor gene implicated in the initiating step in colorectal carcinoma progression. Dysregulation of the APC gene results in Aberrant Crypt [AC] formation, which is the first pre-malignant pathological finding in colonic cancer development. Epidermal Growth Factor Receptors [EGFR] are expressed in most epithelial cancers including colon cancer. Like APC, EGFR is essential for intestinal cell homeostasis. We believe that Statins may regulate EGFR as a possible mechanism to prevent colorectal cancer caused by the inactivation of APC. The goals of this study are: 1) To show the efficacy of statins as chemopreventative and combinational chemotherapeutic agents in colorectal cancer. 2) To show that EGFR-PI3K-Akt is one of the key pathways that is inhibited by cholesterol depletion in Apcmin mice colonic epithelium and adenomas and 3) To further understand EGFR and F-actin interactions in Apcmin mice colonic epithelial and adenoma. Understanding these mechanisms and formulating potential therapeutic targets maybe the future of colorectal cancer treatment. Effective date: September 2006 Angiogenic activity of YKL-40 in colorectal cancer progression: a biomarker for diagnosis of cancer development Secretory protein YKL-40 plays an angiogenic role in the pathological development of colorectal cancer and its elevated level in cancer tissues serves as a biomarker for cancer metastasis. YKL-40 is a secretory glycoprotein normally expressed by chondrocytes and synoviocytes in bone-related tissues. There is evidence indicating patients with multiple types of cancers including breast, colon and ovarian cancer at metastatic stage contain a high serum level of YKL-40. During the past years, we have made large efforts in the understanding of its pathological function and molecular mechanisms. These promising results have formed the basis for our research which largely focuses on YKL-40 gene regulation and molecular mechanism. To provide vital evidence for YKL-40 function in colon cancer development, the current study will investigate YKL-40 angiogenic activity in animal models and human colorectal cancer, which is expected to obtain essential data for a future NCI R21 proposal. The primary goals of this project are: 1) To determine YKL-40 angiogenic activity in cultured cells and xenograft tumor models. 2) To determine a correlation between tissue expression level of YKL-40 and tumor angiogenesis in human colorectal cancer. The proposed study will evidently represent a major effort in identification of a novel biomarker to detect cancer metastasis well as the development of effective therapeutic strategies which will be significantly benefit to colorectal cancer patients. Effective date: September 2006 Biofeedback for fecal incontinence in rectal cancer patients This purpose of the proposed study is to examine the relationship between biofeedback (BF) and education and fecal incontinence (FI) in patients who have just undergone rectal sparing surgery (RSS) for colorectal cancer. The study has three aims: 1) to pilot test instruments to detect function and severity of FI, 2) to pilot test BF techniques in combination with education and nursing support, and 3) to estimate the effect size of these techniques relative to completion of the exercise training, reduction of FI, and increased quality of life (QOL). Patients about to undergo RSS for colorectal cancer will be selected into either the BF education group or the Kegel pelvic floor exercise (PFE) education group. Those enrolled in each group will begin learning their specific training regimen for post-operative management of FI. All subjects will complete preoperative measures of anorectal manometry, FI severity and function and self-reported QOL. These will be repeated 3 months post operatively. It is hypothesized there will be a reduction in episodes of FI and significant differences in FI in the BF group as compared to the PFE group. Effective date: September 2006 Infrared thermography detection of soft tissues infections This investigation will assess the potential for infrared thermography (IRT) to assist emergency providers in the diagnosis and management of localized soft tissue infections. Specific Aim One is to establish whether localized infections generate heat that is detectable with an IRT camera. Specifically, we hypothesize that IRT will detect significantly greater heat over an area of clinically suspected infection than over a non-infected control area over the same anatomic region. Specific Aim Two is to assess whether there are IRT features of abscesses that might allow one to non-invasively distinguish abscesses from cellulitis. We hypothesize that IRT images from abscesses will reveal more intense central heat resulting in a more heterogenous temperature distribution than cellulits, which will have a more homogenous temperature distribution. Both Specific Aims and hypotheses will be addressed in a single, prospective, clinical investigation at Baystate Medical Center’s Emergency Department. After IRB approval from Baystate and UMA, and informed consent and assent (for children) for eligible patients suffering from a localized soft tissue infection, the clinician will be asked whether s/he believes the localized infection is cellulitis or abscess, and administered a Likert scale to quantify their diagnostic certainty. IRT images will be collected using a standardized protocol, prior to any medical interventions, and coded and stored for transfer to UMA for analysis. Next, a single NIRS measurement will be made at the center of the infected area and corresponding control region to assess tissue oxygenation. Ultrasound will be performed to assess for the presence, depth, and dimensions of an abscess. The research assistant will ask the clinician if an incision and drainage will be performed, and if so, upon completion of the incision and drainage, whether turbid fluid consistent with pus was obtained. A two-week follow-up telephone call will be made to assess whether any lesions required subsequent incision and drainage, and to detail the subsequent clinical course. Image analysis will involve three tasks. The first will be the use of statistical techniques to assess whether the IRT temperature intensity and distribution can distinguish infected from control tissue. The second will be the development of restoration algorithms for recovering more accurate skin temperatures from the potentially blurred and noisy IRT images. The final task will be the identification and of skin temperature distribution features that might distinguish abscess from cellulitis. The findings will be applied to future multi-planar, multi-angle protocols and analysis to further improve image interpretation, and perhaps, facilitate 3-dimensional heat imaging. Further, we will apply our findings to investigations of deeper, more serious infections in our NIH R21 grant. Effective date: September 2006 Epigenetic Markers of Breast-Cancer Risk in Breast-Milk Cells Epigenetic, or non-mutation, changes in our DNA accrue over our lifetime, are influenced by our environment and are directly correlated with diseases such as cancer. One epigenetic change associated with breast cancer is the addition of methyl groups, or hypermethylation. Hypermethylation in certain regions of DNA reduces the expression of genes thereby disrupting normal gene function. Using fluid from ductal lavage and nipple aspirate, researchers have demonstrated that the hypermethylation pattern of select genes serves as an early molecular marker of breast cancer. However, studies with nipple aspirate and ductal lavage are often limited due to insufficient cells in the breast fluid. In contrast, a single breast milk sample contains millions of cells shed from the lining of ducts in the breast. We hypothesize that the exfoliated epithelial cells shed into breast milk provide a valid model for examining epigenetic changes related to age, increased breast cancer risk, disease state, and environmental exposures. The objective of this project is to collect preliminary data on the expression of a panel of breastcancer- marker genes in exfoliated epithelial cells isolated from breast milk. The marker genes will be evaluated at three levels: DNA, RNA and protein. We hypothesize that changes occurring early in the development of breast cancer will be detected in cells from breast milk, and that the age of a woman will be positively correlated with an increase in methylation within specific regions of selected genes. Specific Aim: Determine whether the promoter hypermethylation and gene expression patterns of a panel of breast-cancer-marker genes (BRCA1, CDH1, DAP-kinase, GSTPi, p16INK4A, RARB, RASSF1, and TMS1/ASC) examined in exfoliated breast epithelial cells change with age. DNA, RNA, and whole cells will be examined for hypermethylation of CpG islands within promoter regions (Melting Curve Analysis and Pyrosequnecing of bisulfite-treated DNA), mRNA gene expression (Real time RT-PCR), and protein expression (Immunocytochemistry), respectively. Effective date: September 2006 Neuroendocrine Response to Exercise-induced Energy Deficit According to recent data, the majority of adults in the United States are overweight or obese (7). Non-surgical countermeasures designed to reduce body weight and the associated health risks are almost invariably centered on restricting caloric intake to induce an overall energy deficit. These measures have a failure rate, defined as weight loss not maintained for more than 2 years, of 80-95% (10). The high failure rate may be explained by the well-documented metabolic responses to caloric restriction that act to conserve energy expenditure. Caloric restriction lowers resting energy expenditure (REE), energy expended via physical activity (PA), and diet-induced thermogenesis (DIT). Therefore all 3 components of daily energy expenditure (TDEE) respond to caloric restriction in a direction that minimizes accumulated weight loss: REE + DIT + PA = TDEE Caloric Restriction Energy Deficit: ? There are compelling data showing that the marked conservation of energy expenditure in response to caloric restriction is mediated by neuroendocrine factors (e.g. lower concentrations of circulating thyroid hormone, leptin, insulin; higher concentrations of circulating ghrelin) that erve to counter continued weight loss (2). s Instead of caloric restriction, energy deficit can be induced by maintaining caloric intake and increasing energy expended by physical activity (exercise). Since exercise helps preserve lean tissue mass, REE may not decline, and may even increase if there is a significant change in body composition. Since DIT is primarily determined by caloric intake, energy expended by DIT should not decrease if energy intake is not restricted. Therefore, a weight management program based on increasing energy expenditure by PA could result in a strikingly different pattern of changes to TDEE that are more likely to promote continued weight loss: REE + DIT + PA = TDEE E xercise Energy Deficit: The response to exercise-induced energy deficit may be mediated by a different neuroendocrine response from that observed with caloric restriction. How exercise-induced energy deficit impacts the neuroendocrine signals listed above has not been systematically studied. In addition, sex differences in the neuroendocrine response to exercise training have been noted in rodents (1). Data from human and animal studies suggest indeed that increased physical ctivity, with ad libitum feeding, causes loss of body weight in males but not in females (8, 9). a The goal of the current study is to investigate how exercise-induced energy deficit impacts neuroendocrine factors that influence resting energy expenditure. Understanding differences in the neuroendocrine responses to exercise-induced weight loss compared to pure caloric restriction would guide more comprehensive studies centered on mechanisms and end-organ responses e.g. muscle insulin sensitivity and substrate oxidation. To provide the data required to assemble a strong proposal related to exercise and weight loss, the aims of current vestigation are:
Effective date: September 2006 Gene Expression Regulation by Thyroid Hormone in Brown Adipose Tissue This proposal represents the pursuit of research interests of the PIs and is aimed to generate data for a solid, competitive application to the NIH. Dr. Silva has a careerlong interest in thyroid hormone (TH) action and thermogenesis whereas Dr. Zoeller has been interested in the mechanism of action of TH at molecular level. Dr. Silva’s laboratory approached the problem of TH control of thermogenesis using transgenic mice devoid of one or the other thyroid hormone receptor (TR) gene. Results recently published1 show that mice devoid of all know products of the TRα gene (TRα-0/0) have limited thermogenic capacity and are cold intolerant. This is due to the failure of brown adipose tissue (BAT) to increase heat production in response to norepinephrine (NE). Most of known genes in BAT respond appropriately to cold and NE in TRα-0/0 mice1, while mice with deletion of the TRβ (TRβ-/-) are NOT cold intolerant and their BAT thermogenesis increases normally in response to NE. These results suggest that there is a gene or genes necessary for the ultimate thermogenic response of BAT that requires TRα to be regulated by TH. The putative gene product(s) may be necessary for the NE signaling pathway or for the activation of the key thermogenic molecule of BAT, uncoupling protein-1 (UCP1), as explained below. Our Specific Aim is to use high-density oligonucleotide microarrays to identify genes that are TH-dependent and require strictly TRα to respond to this hormone. Genes with this characteristic will be identified by comparing mRNAs extracted from brown fat of wild type (WT) with that of TRα-0/0 mice in the hypothyroid state and in the euthyroid state (hypothyroid replaced with TH), in a 2x2 paradigm with three replicates each (i.e., 12 arrays). Candidate mRNAs will be identified using the Affymetrix Mouse Exon 1.0 ST Arrays through the Full GeneChip Expression Analysis Service at the Keck Foundation Microarray Facility at Yale University. Selected genes will be confirmed for their responsiveness to T3 by qRT-PCR in WT and TRα-0/0 mice. These studies will provide candidate genes essential for BAT responsiveness to TH and will allow, in future studies externally funded, to plan knockin and knockout studies to define their physiological function. Effective date: September 2006 |
||||||||||||||||