Abstract LB-349: ZO1 gene represents a chemosensitivity gene in multiple myeloma

Abstract

Abstract Chemotherapy agents are extremely important in the treatment of liquid malignancies, such as multiple myeloma (MM). Unfortunately, chemotherapy resistance in MM therapy is the most significant cause of treatment failure. The ability to predict, treat, or circumvent resistance is extremely likely to improve clinical outcomes. Thus, identification of novel genes that play a crucial role in MM progression and chemosensitivity is necessary to understand this disease better at the molecular level. Moreover, these genes and their products may serve as new therapeutic targets for MM, whose expression could improve patient outcomes or served as a predictor for chemotherapy outcome. To identify potential chemosensitivity genes, establishing a high-throughput method for validation of targets becomes urgently needed. Toward this purpose, we have successfully developed a high-throughput siRNA based functional target validation approach and identified a group of potential chemosensitivity genes. Our preliminary studies focusing on one of the candidate gene, ZO1 (zonula occludens 1), suggested that targeting ZO1 led to tumor cell resistant to several chemotherapy agents, including doxorubicin (Dox), cisplatin (Cis), methotrexate (MTX), and bortezomib. Further analysis with 264 bortezomib treated MM patients indicated that expression level of ZO1 correlated with patient response to bortezomib treatment. Two clones and pooled RPMI 8226 MM cell line, which were developed against bortezomib treatment in our lab, showed loss of ZO1 expression, suggesting a role of ZO1 may play in bortezomib resistance development. More importantly, ZO1 targeting in myeloma cells resulted in cell resistance to bortezomib treatment. Taken together, our studies reveal a novel chemosensitivity gene, which may lay the foundation for further clinical studies. Moreover, in the clinical arena, it may form a basis for algorithms to help predict chemosensitivity based on baseline gene expression profiles in the future, and may provide the strategies aimed at enhancing chemosensitivity by increasing expression of target genes of interest.[[Unsupported Character -  ]] Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-349. doi:1538-7445.AM2012-LB-349