Molecular Drivers of Elevated Gallbladder Cancer Incidence in New Mexico

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Project Summary: Gallbladder Cancer (GBC) is the fifth most common malignancy of the GI tract and the most common in the human biliary tree. Approximately 4,000-5,000 new cases of GBC are diagnosed in the United States annually. Survival outcomes are dismal with only ~8% 5-year survival rate, making it one of the deadliest cancers. GBC has a distinct geographical incidence pattern with global hotspots. These hotspots include countries like Chile, Bolivia, India and the state of New Mexico (NM) in the United States. GBC incidence is abnormally high among the “minority-majority” Native Americans (5-8 fold higher) and Hispanics (2-4 fold higher) compared to Caucasians living in New Mexico. The reasons underlying GBC incidence disparities in NM is unknown and there are critical gaps in our understanding of gallbladder carcinogenesis. We postulate environmental heavy metal exposure is the key risk factor responsible for GBC disparities seen among minorities of NM. The southwestern United States (NM, AZ, UT and NV) has a long environmental legacy of abandoned heavy metal mines. These mines are usually found in close proximity to a significant number of socio-economically disadvantaged Native American and Hispanic communities of NM. To prove our GBC hypothesis, we propose the use of New Mexican patient derived gallbladder epithelial cell lines in this proposal. Aim 1 will use post-surgical gallbladder samples to determine the somatic mutational landscapes and key molecular drivers of GBC in an ethnicity and gender dependent manner. Aim 2 will determine the impact of exposures of two metals of significance in New Mexico, uranium and cadmium, on the GB phosphoproteomic cell signaling dysregulation. In particular, we will focus on the role of metal exposure driven PI3K-Akt and MAPK signaling pathway alterations. Aim 3 will determine the effects of cadmium and uranium exposure on gallbladder epithelial barrier disruption and wound healing as a mechanistic explanation of GBC disparities seen in NM. Aim 3 will confirm, for the first time, the role of metal induced disruption of the GB epithelial barrier causing chronic transmural inflammation which is a well-known prerequisite of gallbladder carcinogenesis. Our long-term goal is to understand the molecular mechanisms of gallbladder carcinogenesis using innovative, high-throughput bioinformatics approaches. This basic science proposal deeply informs the translational clinical initiatives currently underway in our lab. Finally, this proposal will also provide a firm scientific basis to enable preventative, population based screening measures to alleviate GBC disparities seen in Native American and Hispanic communities of New Mexico.