Although membrane trafficking regulators have been linked to cancer there is relatively little known about these proteins contribution to tumorigenesis. As these proteins are essential for cellular transport in signaling we hypothesized that alterations in the expression of trafficking regulators may be important in cancer. Our understanding of cancer mechanisms has been advanced by our ability to analyze the expression of genes on a genome wide scale. We have employed this strategy to identify novel roles for proteins reported or predicted to function in membrane trafficking that are differentially expressed in cancer. Previously, I carried out expression profiling via analysis of microarray data on 650 genes associated with membrane trafficking, referred to as the membrome. This analysis was performed on tumors from the major cancers affecting the population. From this analysis I observed a higher level of membrome proteins, including Rabs, expressed in pancreatic cancer. Since starting my lab at the NCI this year we have collaborated with Laufey Amundadottir at NCI DCEG to further examine the expression of membrome proteins in pancreatic tumors and cells lines using RNA seq. Using both these approaches and data available from the NCI60 and expression data published in the literature we have identified candidate genes for further investigation. We have initiated an MTA to bring to the NIC a lentivirus expression system that enables inducible expression of short hairpin RNA (shRNA) in order to deplete the expression of candidate proteins in cells. Using RNA interference candidate proteins will be monitored for gain or loss of function effects on cell growth, apoptosis, motility, and other tumor related functions in cultured cell lines. shRNA expressing cells will also be used in mouse xenograft studies to examine functions in tumor formation and metastasis.
