Lung cancer is the leading cause of cancer deaths in the United States, largely due to complications associated with metastasis. In many cancer types loss of cancer cell differentiation correlates with metastatic ability and poor patient prognosis. Identifying the drivers of lung cancer differentiation and metastatic potential and the underlying mechanisms by which this state is induced, reversed or maintained is a question of immense clinical importance and may provide new targets for anti-metastasis therapy. Genetically engineered mouse models of lung adenocarcinoma provide an opportunity to study lung tumor progression and metastasis in vivo. The proposed work will identify regulators of tumor differentiation and metastatic progression and define how Lkb1 tumor suppressor deficiency gives rise to more frequent and well-differentiated metastases in the presence of functional p53. We hypothesize that differential gene expression between primary tumors and their metastases will identify key determinants of lung cancer differentiation and metastatic progression in vivo. We have recently used RNA-seq to identify differentially expressed genes between tumors and their metastases and validated a subset of these genes by Fluidigm(R) microfluidics PCR. Preliminary data demonstrate that knockdown of Plod2 and expression of Sh3rf2 decrease the metastatic properties of mouse metastatic cell lines. We have improved upon existing lung adenocarcinoma mouse models enabling us to alter genes in developing tumors in vivo and to isolate cells from all stages of cancer progression. In addition, we have developed a barcoded Cre-lentivirus allowing disseminating tumor cells and their metastases to be ascribed to their primary tumor of origin.
Aim 1 will systematically dissect gene function responsible for tumor differentiation state during lung cancer progression and metastasis. Human and mouse lung cancer cells will be used to assess the ability of candidate genes to influence the differentiation and malignant states of lung cancer cells in vitro.
Aim 2 will identiy key determinants of lung cancer differentiation and metastatic progression in genetically engineered mouse models of lung adenocarcinoma by altering target gene expression in developing lung tumors in vivo using lentiviral vectors that co-deliver Cre and a cDNA or shRNA.
Aim 3 will determine the mechanisms by which Lkb1 controls tumor differentiation and metastatic potential. I will use barcoded Cre-lentivirus to determine the clonality, differentiatio capacity, and metastatic ability of Lkb1-deficient disseminating tumor cells. These studies will increase our knowledge of factors that mediate lung adenocarcinoma progression and metastasis with the potential to identify new targets for intervention. Given the immense clinical impact of metastatic cancer and lack of knowledge regarding tumor cell plasticity and differentiation capacity, I suggest that both clinical practice and patient outcome could be greatl influenced by any new therapies that result from the fundamental knowledge gained from these studies.
Metastasis is responsible for >90% of cancer-associated deaths, however, insight into the mechanisms governing tumor differentiation and metastatic progression in humans is sorely lacking. This project functionally interrogates novel regulators of cancer cell differentiation and metastatic ability by altering gene expression in human cancer cells and genetically engineered mouse models of metastatic human lung adenocarcinoma. Ultimately, the knowledge gained from these studies has the potential to improve patient outcome by identifying new targets for anti-metastasis therapy in the clinic.