Role of AMPK in melanoma brain metastasis

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Project Summary: AMP activated protein kinase (AMPK) is a critical evolutionarily conserved energy sensor that regulates energy homeostasis by monitoring changes in the intracellular AMP or ADP to ATP ratios. Mounting evidence supports that the AMPK pathway is one of the major signaling players at the interface of metabolism and cancer. However, the role of AMPK in tumor progression and metastasis remains obscure. Our recent analysis on melanoma cancer genomics data has revealed that the mutations in the PRKAA2 gene, which encodes the alpha 2 catalytic subunit of AMPK, occur in 8-10% of cutaneous melanomas and tend to co-occur with NF1 mutations. In our preliminary studies, we found that knockout of AMPKα2 promoted anchorage-independent growth of mutant NF1-melanoma cells in soft agar assays and their growth as xenografted tumors in nude mice. Importantly, we found that expression of AMPKα2 is significantly downregulated in human melanoma brain metastasis samples compared to patient-matched extracranial metastasis samples. Furthermore, knockout of AMPKα2 promoted brain metastasis of NF1-mutant Mewo melanoma cells in nude mice. Based on these preliminary results, we hypothesize that inactivation of AMPKα2 in melanoma promotes tumor progression to melanoma brain metastasis. In Aim 1, we will establish the role of AMPKα2 in melanoma brain metastasis using mouse models and human samples. We plan to characterize the effects of AMPKα2 loss in both syngeneic and genetically engineered mouse models. Human melanoma brain metastasis samples will be used to explore the contribution of AMPKα2 loss through spatial single cell RNA-seq analyses. In aim 2, we will characterize downstream targets of AMPK involved in the metabolic regulation of melanoma brain metastasis. We will investigate the contribution of a novel putative substrate of AMPKα2 involved in de novo lipogenesis, identified in our preliminary studies, to melanoma brain metastasis, and explore additional new AMPKα2 targets through comprehensive metabolomics and RPPA analyses of tumor samples from mouse models. In aim 3, we will assess the therapeutic effects of metabolic drugs targeting the AMPK pathway on enhancing the efficacies of targeted- and immune- therapies in melanoma brain metastasis using human melanoma xenografts, syngeneic and genetically engineered mouse models. To achieve these aims, we have assembled a team of investigators with various expertise including cancer cell metabolism, melanoma brain metastasis biology, melanoma oncologists/surgeon and computational biology. Our study will not only provide critical insights into the role of AMPK metabolic signaling in melanoma brain metastasis addressing a significant knowledge gap in the field, but also identify novel therapeutic approaches to target melanoma brain metastasis.