Abstract 3514: A genetic-metabolic circuit of liver-specific metastatic organotropism
Authors: Rogava Meri , Aprati Tyler Joseph , Chen Wei-Yu , Melms Johannes , Hug Clemens , Amin Amit Dipak , Ngo Bryan , Lee Michae l , Ho Patricia , Wang Yiping , Tang Stephen , Earlie Ethan , Chen Sean , Tüting Thomas , Röcken Martin , Eigentler Thomas K. , Bakhoum Samuel F. , Molotkov Andrei , Mintz Akiva , Schadendorf Dirk , Cantley Lewis C. , Sorger Peter K. , Laughney Ashley , Liu David , Izar Benjamin 
Published: April 2023

Abstract
Liver metastasis (LM) occurs frequently in patients with melanoma and is associated with a poor prognosis and reduced therapy response. To identify drivers of metastatic niches, we used a syngeneic mouse melanoma model which recapitulates genomic, metastatic and therapy response patterns seen in patients, and performed a large-scale in vivo CRISPR-Cas9 knockout screen, which identified perturbations that strongly promoted liver but not lung metastasis. The “top hit” in this screen associated with LM was loss Pip4k2c. Mechanistically, loss of Pip4k2c sensitized both mouse and human melanoma to insulin-mediated PI3K/AKT pathway activation. Interestingly, this observation was dependent on the allosteric but not kinase domain activity. Treatment with different PI3K inhibitors abrogated the pathway in vitro, but was partly bypassed in the presence of insulin. As expected, loss of Pip4k2c was associated with significant increase in LM but not lung-metastatic burden in both syngeneic and patient-derived xenograft models, and this phenotype was rescued by reconstitution of full-length, but not allosteric domain deficient Pip4k2c constructs. We reasoned that Pip4k2cKO cells preferentially colonized the liver by co-opting the insulin-rich milieu in this organ. To test this, we generated Pip4k2c-/-/InsrshIR-KD and showed that Insr was required but not sufficient to enhance LM burden. Surprisingly, treatment with PI3K inhibition in vivo resulted in increased and not decreased LM burden as we had expected. PET-CT imaging of animals treated with PI3K revealed increased glucose uptake in LM in the presence of PI3K inhibition. We therefore reasoned that paradoxical activation due to host-mediated increase in glucose and insulin in response to PI3K inhibitor, may results in increased homing and metastasis to the liver. In further in vivo experiments, we showed that breaking this loop with either SGLT2 inhibitor or ketogenic diet circumvented host responses and resulted in reduced LM burden, while having no effect on lung metastasis burden. To further substantiate these findings, we performed single cell RNA-seq of concurrent liver and lung metastasis bearing mice which revealed strong tumor-intrinsic enrichment of central carbon metabolism. Lastly, analysis of 243 human liver vs extra-hepatic metastases across 75 cancers and addition of newly generated RNA-seq data of additional melanoma LM, revealed concordant pathways enrichment of glycolysis and oxidative phosphorylation LM. Together, we identify an axis of liver-metastatic organotropism that can be abrogated with a combination of PI3K inhibition and SGLT2-inhibition or concurrent ketogenic diet.
Citation Format: Meri Rogava, Tyler Joseph Aprati, Wei-Yu Chen, Johannes Melms, Clemens Hug, Amit Dipak Amin, Bryan Ngo, Michae l Lee, Patricia Ho, Yiping Wang, Stephen Tang, Ethan Earlie, Sean Chen, Thomas Tüting, Martin Röcken, Thomas K. Eigentler, Samuel F. Bakhoum, Andrei Molotkov, Akiva Mintz, Dirk Schadendorf, Lewis C. Cantley, Peter K. Sorger, Ashley Laughney, David Liu, Benjamin Izar. A genetic-metabolic circuit of liver-specific metastatic organotropism [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3514.