While MMP activity is normally tightly regulated, both at the expression level and by endogenous tissue inhibitors of metalloproteinases (TIMPs), PS-341 purchase dysregulation of MMP activity has been linked to many pathological conditions, including cancer progression and metastasis. The expression of MMPs in colorectal carcinoma (CRC), including MMPs-1,2,7,9 and 13,

has been correlated with disease prognosis. We have previously shown that tumour microenvironmental factors regulate the cell-surface levels of CD26 and CXCR4, two proteins involved in the migration and invasion of CRC cells. While there is evidence linking the expression of MMPs to cell regulation through CXCR4, no information is available to address whether MMPs are important in the overall response of CXCR4 and CD26 to the cellular microenvironment, or whether there is a link to CD26 regulatory pathways. In

this work we examined whether different factors, or stressors, found in the tumour microenvironment were able to regulate MMP-7,9,13 and TIMP-1-3 mRNA expression and protein secretion. We show that such tumour microenvironmental stressors, including adenosine and its metabolites, are able to enhance mRNA expression of MMP-7,9 and 13 as determined by quantitative RT-PCR. Additionally, Western blot analysis indicated that these microenvironment Crizotinib manufacturer stressors are not only able to increase gene expression, but also enhance MMP protein secretion. Together, these data suggest that factors in the tumour microenvironment are able to regulate changes in protein expression, possibly playing a role in the migratory phenotype of the CRC cells in a local context. These changes may work alongside with, and possibly be mechanistically linked to, the down-regulation of CD26 and up-regulation of CXCR4 that occurs under the same conditions. Supported by an NSERC award to J.B. and studentship award to K.T. from CRTP. Poster No. 36 The Contribution of the Immune System to Initiation and Progression of Pancreatic Ductal Adenocarcinoma Renee Vander Laan 1 , Geraldine

Bienvenu1, Matthias Hebrok1 1 Diabetes Center, Department of Adenosine triphosphate Medicine, University of California, San Francisco, San Francisco, CA, USA In many cancers, the inflammatory response has been shown play a role in tumor formation, progression and metastasis. Although the immune microenvironment has been characterized during the preneoplastic and invasive stages in a mouse model of pancreatic ductal adenocarcinoma (PDA) (Clark et al 2007), the inflammatory response involved in initiation of preneoplastic lesions called pancreatic intraepithelial neoplasias (PanINs) is unknown. Additionally, the functional involvement of immune cells in tumor development and the progression of PDA is unclear.