Abstract 4511: HIF-1-dependent regulation of creatine kinase metabolism promotes breast cancer invasion and metastasis

Abstract Dysregulated tumor cell metabolism is a hallmark of cancer progression and therapeutic resistance. In a screen for Hypoxia-Inducible Factor (HIF)-dependent genes regulating metabolism, we identified creatine kinase, brain isoform (CKB) as down-regulated in HIF-1 knockout mammary tumor cells. Creatine kinases (CKs) reversibly catalyze the transfer of a high-energy phosphoryl group from ATP to creatine, generating phosphocreatine in the forward reaction, and ATP in the reverse reaction. CKs are up-regulated in a variety of solid tumors, including ovarian, breast, colon, lung and brain. Knockdown of CKB in the polyoma middle T (PyMT) transgenic mouse model of metastatic breast cancer suppressed the production of intracellular ATP and invasion in vitro, and inhibited metastasis from the mammary gland to the lung in vivo. CK activity is known to be inhibited by cyclocreatine, a creatine kinase substrate that represses CK-dependent generation of ATP from phosphocreatine. When female FVB/Nj mice were injected with wild type PyMT cells in a tail vein assay and then treated with cCr (1g/kg/day, IP), lung metastasis was repressed to the same extent as Ckb gene knockdown. Moreover, when cCr therapy was administered 7 days after tail vein injection, cCr was effective in preventing the transition of lung micrometastases to macrometastases. To explore the role of CK activity in regulating cell proliferation, survival in suspension, cellular metabolism and invasion, we next created CKB loss- and gain-of-function models using human breast cancer cell lines, and compared phenotypes to cCr treatment. Whereas deletion of CKB had no effect on cell proliferation or survival in adherent conditions or in suspension, either deletion of CKB or cCr therapy potently reduced ATP levels and invasive potential in vitro. Preliminary data also indicate that pre-treatment of triple negative breast cancer cell lines with cCr sensitizes cells to doxorubicin. Together, these data suggest that inhibition of CK activity may be effective in treating stage IV breast cancer. We are currently testing whether cCr has anti-metastatic efficacy as a monotherapy, or in combination with conventional chemotherapies, using luciferase-labeled patient-derived xenograft (PDX) models. This work was sponsored by the NIH (CA138488), the Dept. of Defense (BC150640), the METAvivor foundation, and the West Cancer Center in Memphis, TN. Citation Format: Hilaire Barch, Danielle L. Brooks, Raya Krutilina, Luciana P. Schwab, Deanna Parke, Tiffany N. Seagroves. HIF-1-dependent regulation of creatine kinase metabolism promotes breast cancer invasion and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4511. doi:10.1158/1538-7445.AM2017-4511