This application is being submitted in response to the Notice of Special Interest (NOSI) identified as NOT-CA-20-020. The work will initiate a unique collaboration between research groups at OHSU (Agarwal Lab) and WUSTL (Lim Lab) to identify the mechanisms by which the tumor microenvironment (TME) contribute to the drug resistance in cancer using a 3D multicellular tumor organoid model. The bi-directional communication between cancer cells and microenvironment is much more complex than initially perceived. In general, the tumor microenvironment provides nutrient supplies and survival signals to cancer cells, resulting in tumor development, metastasis, and therapy resistance. Therefore, cutting off these resources represents an effective anti-cancer strategy. Most of the traditional in vitro drug screening approaches does not mimic the components of tumor microenvironment, thereby may account for high failure rates of the resultant regimens in clinical trials. Here we propose to develop a novel in vitro 3D multicellular tumor organoid model that will closely recapitulate the in vivo tumor microenvironment to improve our understanding of cancer cell-microenvironment interactions. We will use this model to study pancreatic ductal adenocarcinoma (PDAC) and acute myeloid leukemia (AML), where treatment resistance is a major challenge. Preliminary data from both labs show that the secreted factors from microenvironment play an important role in conferring drug resistance to MAPK pathway inhibitors in both AML and PDAC. In patient-derived xenograft (PDX) models of PDAC, in vitro drug sensitivity to MAPK pathway inhibitor differs greatly between monolayer culture and when grown in mice, strongly suggesting the TME as an essential component that is missing in the current culture system. Therefore, the Lim lab developed a novel 3D heterotopic models comprising of cancer-associated fibroblasts (CAFs) and tumor cells. In this proposal, we will adopt this 3D organoid model to perform functional drug screening and understand the mechanisms of drug response in AML and PDAC. We will test the hypothesis that heterotypic 3D organoid model will better mimic therapy response for AML and PDAC cells in their native environment. Specifically, we will utilize primary AML cells and cell lines from the OHSU group and cells derived from PDAC PDX model to perform drug testing in 96 well plate format for trametinib (CTEP drug) as single agent and as combination with FDA approved drugs. We will test the effect of these inhibitors on cell viability, cellular composition, differentiation, and target inhibition using multi-parametric flow cytometry and immunofluorescence analysis. We will identify the secreted cytokine landscape in microenvironment and impact of these on the growth and survival of tumors cells. The data integration and pathway analysis will be performed to identify unique therapeutic targets. Perturbing the supporting cells of the microenvironment and cancer cells together may offer more effective therapeutic strategies to overcome drug resistance. These multicellular functional 3D assays to measure drug response will have broader applicability. Translation of these findings will improve the outcome of patients with deadly cancers.
The tumor microenvironment plays a major role in cancer progression and therapy resistance. In this collaborative proposal, we will establish a cost-effective and feasible 3D heterotypic organoid model as a screening tool to discover novel drug combinations that overcome therapy resistance and identify novel markers of drug resistance in acute myeloid leukemia and pancreatic cancer, two of the most aggressive cancer types. We will establish a clinically relevant 3D model that can be used for drug discovery and applicable to many cancer types.
