Abstract 3429: AKAP12/SSeCKS inhibits peritoneal metastasis by regulating chemokine production

Abstract

AKAP12/SSeCKS/Gravin (AKAP12) is thought to act as a metastasis suppressor through its direct scaffolding of major signaling proteins such as PKC, PKA and Src, in a spatiotemporal manner (1). For example, AKAP12 inhibition of Src-mediated oncogenic signaling, including induction of VEGF secretion by tumor cells, correlates with inhibition of neovascularization at metastatic sites (2). We have established AKAP12-null (KO) mice and demonstrated that they are cancer-prone in regards to the formation of spontaneous prostatic dysplasia and to carcinogen-induced skin cancer formation (3, 4). However, the role of AKAP12 in host microenvironment in regards to tumor or metastasis control has yet to be elucidated. In this study, we utilized an orthotropic, subcutaneous injection model of B16F10 melanoma to address whether the loss of AKAP12 in the host facilitates metastasis. Although the size of the primary tumors was similar in WT vs. KO mice, KO mice exhibited increased rates of peritoneal metastasis. The peritoneal fluid (PF) of KO mice was more potent than WT-PF in inducing in vitro chemotaxis. Comparison of the cytokines/chemokines using antibody arrays showed a severe upregulation of multiple potential chemoattractants in the KO-PF, including CXCL9/10/11, known ligands for CXCR3, a chemokine receptor upregulated 12-fold in B16F10 versus the low-metastatic B16F0 variant. Pre-injection of KO-PF, but not WT-PF, into WT mice was sufficient to induce high levels of peritoneal metastasis from subcutaneous sites. Taken together, our study suggests that AKAP12 controls metastasis by regulating the production of chemoattractants in the peritoneum, produced either by local microenvironmental cells or by recruited inflammatory cells. References: (1) Gelman, I. H. (2002) Front Biosci 7, 1782-1797. (2) Su, B., Zheng, Q., Vaughan, M.M., Bu, Y., and Gelman, I.H. (2006) Cancer Res. 66, 5599-5607 (3) Akakura, S., Huang, C., Nelson, P. J., Foster, B., and Gelman, I. H. (2008) Cancer Res. 68, 5096-5103. (4) Akakura, S., Bouchard, R., Bshara, W., Morrison, C., and Gelman, I. H. (2011) Int. J. Can. 129, 2025-2031. 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 3429. doi:1538-7445.AM2012-3429