Poster abstracts
Poster number 5 submitted by Marcos Corchado
Elucidating the role of the mesoderm in let-60/Ras-mediated over-proliferation of epithelial cells in C. elegans
Marcos Corchado (Department of Molecular Genetics, The Ohio State University), Komal Rambani (Biomedical Sciences Graduate Program, The Ohio State University), Helen Chamberlin (Department of Molecular Genetics, The Ohio State University), Gustavo Leone (Department of Biochemistry, Medical College of Wisconsin)
Abstract:
Mesoderm-to-epithelium signaling plays an important role in the maintenance and progression of tumors, as mesodermal-derived cells comprise much of the microenvironment during cancer. The influence of the tumor microenvironment has been well documented, however, identification of the genes important in mediating environment-tumor interactions has been limited due to the complexity of stromal tissue in mammals. To overcome this challenge, we developed a simple model for the mesoderm-to-epithelium signaling using the nematode C. elegans. In this system, we genetically engineered let-60/Ras-sensitized animals to have tissue-specific activity of RNAi in the mesoderm. Using this strain, a genome-wide RNAi screen was performed to identify mesoderm-specific suppressors of let-60/Ras. To validate RNAi experiments, we generated genetically chimeric null animals and confirmed the cell non-autonomous suppression activity of two genes, hpo-18 and szy-5. hpo-18 encodes a mitochondria-specific ATPase while szy-5 encodes a zinc-finger domain-containing protein. To better understand how these two genes impact mesoderm-epithelium communication, we have focused on characterizing their role in the Anchor Cell (AC), muscle, and gonad, the three tissues that comprises the mesoderm. Previous research has shown the influence of AC mitochondria localization and ATP enrichment on basement membrane (BM) degradation and subsequent effects on vulva development. Therefore, we performed fluorescent imaging of the AC mitochondria and the BM structural protein lam-1 upon knockdown of hpo-18 and szy-5 which showed no difference in mitochondrial localization or BM integrity compared to wildtype. Similarly, RNAi knockdown show no effect on gonad morphology and muscle function. These results suggest that these cellular processes still occur under loss of either gene. The value of the tissue-specific RNAi screens presented in this research is the ability to identify let-60/Ras suppressors that otherwise may have been masked by lethal or developmentally arrested phenotypes in whole animal knockdown. To this extent, we present novel regulators of mesoderm-to-epithelium tissue communication and epithelial cell proliferation.
Keywords: Cancer, Microenvironment, C elegans