Microtuble-associated TPX2 is amplified in pancreatic cancer Free

LB-315

With the worst five-year survival rate of any cancer, pancreatic adenocarcinoma now ranks as the fourth leading cause of cancer death in adults in the United States. This necessitates increased efforts to identify new leads that will serve as therapeutic targets. TPX2 (targeting protein for Xenopus kinesin-like protein 2) constitutes an important component of the spindle apparatus and is required for both the stability of the mitotic spindle and the localization of Aurora A kinase to the spindle microtubules. Recent studies have shown that this gene is amplified in a subset of pancreatic adenocarcinomas (PNAS 2005;102:9625-30), implicating TPX2 as a potential oncogene due to its involvement in this established signaling pathway. In this study, we attempt to further characterize the amplification of TPX2 in multiple pancreatic cancer cell lines and in human pancreatic xenograft tissues using the complementation of quantitative PCR (qPCR) and comparative genomic hybridization (CGH) to assess TPX2 gene copy number as an indication of its role in tumorigenesis. We screened 17 pancreatic cancer cell lines and 20 xenograft tumors from low passage pancreatic cancer cell lines (Clin Cancer Res. 2006 Aug 1; 12(15):4652-61) using real-time qPCR and found TPX2 to be amplified above two copies in approximately half of the cell lines and two-thirds of the xenografts. CGH was likewise carried out on the same specimens using Agilent’s 60-mer oligonucleotide whole genome 244k arrays. Combining qPCR with CGH array data allowed for the quantitative assessment of the fold of amplification of a single gene in the context of genome and/or chromosome-wide aberrations. The TPX2 amplifications within the pancreatic cancer cell lines and tumor xenografts varied from focal amplification within 20q11.21, to the whole q-arm and the entire chromosome 20. The level of amplification reached as high as six copies of the TPX2 gene in some samples. These results suggest that TPX2 may be important in pancreatic cancer, is a potential candidate oncogene and a prospective therapeutic target to treat this disease. (Supported by NIH Grants R01CA95031 and P01CA109552)