Pharmacological inhibition of LKB1-NUAK1 signaling in a spheroid model of ovarian cancer metastasis

Epithelial ovarian cancer (EOC) is a lethal gynecologic cancer, usually only diagnosed after widespread metastasis. EOC metastasis is unique, spreading through multicellular aggregates or spheroids. Previously, we demonstrated Liver kinase B1 (LKB1)-NUAK1 signalling promotes spheroid integrity, reattachment, and fibronectin production, in response to bioenergetic stress. Using genetics-based CRISPR deletion cell lines, we have solid evidence that LKB1-NUAK1 signalling plays crucial roles in EOC metastasis, therefore providing new therapeutic targets. The compound ON123300 is an established inhibitor for NUAK1, however, there are no known small molecule inhibitors of LKB1. Working with the OICR, we identified ASC-069 and Dinaciclib as lead compounds, which have been modified to improve LKB1 specificity. This research aims to compare the pharmacologic inhibition of LKB1 and NUAK1 focusing on metastatic properties of EOC spheroids. From our previous studies, and its position upstream in the pathway, we hypothesize LKB1 inhibition will have a greater impact on blocking metastatic properties of EOC spheroids as compared with NUAK1 blockade. Spheroid reattachment assays and Transwell migration/invasion assays will be performed to evaluate LKB1 and NUAK1 inhibition on metastatic properties of spheroids in culture. Early results indicate that spheroid viability and dispersion following reattachment are more potently reduced by LKB1 inhibitors compared to ON123300. We will verify on-target LKB1-NUAK1 inhibitory activity in spheroids; we have preliminary data that fibronectin expression is potently reduced following ON123300 treatment of spheroids. We are the first to develop potential small molecule inhibitors against LKB1 which will be important tools for the field as potential anti-cancer therapeutics.