California State University, Fresno is located in the Central San Joaquin Valley which has one of the highest Hispanic populations in California with a high percentage of farm workers due to the agricentric region. We believe farm workers represent an at-risk population with increased exposure rates to environmental carcinogens which could impact their health and put them at increased risk for certain cancers. Therefore, the long-term goal of the Fresno State/SBCC Partnership is to establish a baseline on the incidence of pancreatic and breast cancers among Hispanics in the Central California region, and eventually reduce the incidence of these cancers.
We are strategically targeting two joint research pilot projects that emphasize cancer disparities and at-risk populations that are common to our region.
Pilot Project 1 :
Secretome evaluation of primary cultures derived from pancreatic ductal adenocarcinomas
PI: Jason Bush, PhD (Fresno State)
Co-leaders: Dieter Wolf, MD (SBCC)
Guy Salvesen, PhD (SBCC)
The prognosis for individuals with pancreatic cancer is dismal. Currently, no standard cure for metastatic cancer of the pancreas is available. Consequently, new biomarkers indicative of early pancreatic disease must be developed for more effective diagnoses. The shortcomings of genomic studies must be circumvented by identifying candidate proteins through the power of mass spectrometry. To date, approximately 100 studies exist in the literature detailing direct applied proteomic research to a variety of different pancreatic cancer sample types and each category of specimen (i.e. blood/serum, pancreatic juice, and pancreatic cancer tissue) has both advantages and limitations associated with its use. Comparison of the different studies is problematic due to the diversity of methodologies, sample sources, and sometimes poor characterization of the patient populations. The key objective of this study is to uncover differences in the proteomic signature among advancing stages of pancreatic cancer cells. Cancer of the pancreas primarily occurs in the exocrine portion of the organ, with fewer occurrences in the endocrine section such that approximately 95% of cancerous exocrine tumors (carcinomas) are derived from ductal cells, while a smaller fraction of tumors are from acinar cells. This proposal is exploratory and data-driven in nature and seeks to establish a model of primary cultures from a range of pancreatic tumor resections that will be grown and maintained on biologically relevant substrates (synthetic basement membranes) to emulate the ductal environment, and also adapted to serum-free conditions. We will then use our systematic proteomic workflow to identify low abundant proteins. We have developed a powerful approach based on cell lines as proof-of-concept and will incorporate enhancements to the workflow (that have not been detailed in the literature) for innovation and drive our chances for novel, productive biomarker discovery. Once cultures are established, a systematic approach of investigating the secretome (secreted proteome) including, protein extraction, differential labeling, and LC/MS/MS will be undertaken. The comprehensive proteomic analysis of these pancreatic cancer cells will reveal unique proteins involved in the progression of pancreatic adenocarcinoma.
Pilot Project 2 :
Investigating the role of xenobiotic exposure in breast cancer for Hispanic farmworkers of the Central Valley
PI: Krish Krishnan, PhD (Fresno State)
Co-leaders: Paul Mills, PhD (UCSF-Fresno)
Maurizio Pellecchia, PhD (SBCC)
Guy Salvesen, PhD (SBCC)
Environmental substances or xenobiotics seem to be involved in the etiology of breast cancers. Several studies have found an association between human cancer and exposure to agricultural pesticides such as the organochlorine compounds (OC); therefore, farmworkers may be at higher risk for acute and chronic health effects associated with pesticides. The objective of this pilot project is three-fold, 1) obtain epidemiological data specific to breast cancer incidence/mortality rates in areas of high and low xenobiotic usage, 2) elucidate a potential correlation between biomarkers derived from human saliva and clinical risk factors for breast cancer in Latina farmworkers of the Central Valley, and 3) expose normal human mammary epithelium in culture with organochlorine chemicals to determine both the metabolite profile and the biological effects. This is responsive to the health disparity of Hispanic farmworkers in the Central Valley. For Phase 1, student researchers will gain valuable experience in biostatistics by interrogating and parsing cancer registry data to calculate ageadjusted incidence/mortality rates for cancer and pesticide usage in underserved populations of the Central Valley. Focus will be the occupational exposure associated with farmworkers and the identification of databases from which other variables pertinent to cancer epidemiology could be useful. Specific to breast cancer, individual breast cancer cases (and healthy “controls”) will be approached and recruited for entry into a breast cancer case-control study in which both questionnaire-based information and saliva specimens are collected. For Phase 2, clinically-relevant DNA will be extracted from saliva and genotyped for putative polymorphisms in common detoxifying genes of the CYP and GST families. Metabonomic profiles will be generated from saliva using multidimensional (2D, 3D) NMR spectroscopic methods as a means to evaluate the clinical utility for multivariate analyses with breast cancer risk factors. For Phase 3, student researchers will test the biological effects of OC on normal human mammary epithelial cells by determining metabolite profiles using high-resolution NMR. Finally, long-term dosing experiments and CYP or GST knockdown cellular systems will be established to phenocopy clinical relevance. This innovative pilot project takes students through a range of cancer research aspects from identifying at-risk populations to molecular analyses of the problem.