Organoid models of KRAS mutant cancer

Division Of Basic Sciences - Nci

Investigators

Linked publications & trials

Abstract

surfaces does not accurately reflect their transformed phenotype. A key hallmark of cancer, in fact, is the ability of these cells to grow independently of anchorage. While 3D anchorage-independent cultures can form spheroids that mimic microscopic tumors, their utility has been limited by the difficulty and cost of growing 3D culture on a large scale. Developing a more scalable and cost-effective method for culturing tumor spheroids would greatly expand their use in cancer research. Recent advances in organoid culture have also made it possible to grow primary epithelial cells while maintaining their lineage identity in vitro. For instance, in the lung, alveolar type 2 (AT2) cells, the resident stem cells of the alveolar space, are believed to be the cell of origin for lung adenocarcinoma. Therefore, a scalable murine lung organoid model of both normal and KRAS mutant AT2 cells would more closely resemble lung cancer in vivo. These advanced cell models will be crucial for dissecting the function of the KRAS oncogene in the context of anchorage-independent cell growth. OBJECTIVES. 1) To develop human tumor spheroid cultures to study how the KRAS oncogene functions in an anchorage-independent environment; 2) to create scalable murine organoid models of KRAS mutant cancer to investigate KRAS oncogene function in lung and colon epithelial cells; and 3) to establish orthotopic transplant models in mice using both tumoroids and organoids to study the interaction between tumor cells and the tumor microenvironment. MAJOR ACTIVITIES, SIGNIFICANT RESULTS AND KEY OUTCOMES. 1) Elucidating KRAS oncogene function under anchorage-independent conditions. We have developed a scalable tumor spheroid culture method applicable to many epithelial KRAS mutant cancer cell lines. This system allows for the molecular and genetic dissection of cellular phenotypes. Using this approach, we have identified features of KRAS oncogenic signaling distinct from those observed in 2D cell culture. We are investigating the functional impact of these 3D-specific signals from the KRAS oncogene and how they contribute to cellular transformation. 2) Using AT2 organoids to model lung adenocarcinoma in vitro. We have established organoid cultures of Kras mutant mouse AT2 cells to study the biology of KRAS mutant lung adenocarcinoma. These organoids stably maintain their AT2 lineage markers, exhibit features of transformation, and are addicted to the KRAS oncogene for their growth and tumorigenic capacity. We are using this system to understand how mutant KRAS impacts signaling, gene expression, and stemness in AT2 cells. In parallel, we are developing organoid cultures of normal AT2 cells to understand how targeted therapies affect their viability. To model human lung adenocarcinomas, we are developing methods to stably culture normal and KRAS-transformed human lung AT2 organoids to examine the function of the KRAS oncogene in human AT2 cells.