Isolated and characterized colorectal cancer stem cells and normal stem cells isolated from colorectal cancer tissues and normal colon tissues by whole genome expression microarray

Cancer stem cells (CSCs) are pluripotent cells that have been implicated in tumor proliferation, metastatic dissemination, and recurrence of various cancers. The prognosis of colorectal cancer, which often presents late due to absence of early symptoms, depends on the stage at presentation. In the present study we have isolated and characterized cancer stem cells from colorectal cancer tissues and normal stem cells from normal colon tissues. Only sporadic colorectal cancer cases were considered where the patient had not received any neo-adjuvant therapy to avoid any bias introduced in the cellular transcriptome by external agents. Normal colon tissues were taken from adjacent region of resected specimen as well as non-cancerous operative colon cases. For our study, we have used cancer and normal stem cell markers defined in established literature. For isolating cancer stem cells by FACS, CD44 and CD166 tagged to phycoerythrin (PE) and Alexa Fluor 647 respectively, were used. For isolating normal colon stem cells, CD29, tagged to PE, and Lgr5, tagged to Alexa Fluor 647 were used. Only dual marker-positive cells were isolated to get an enriched population. Tumor sphere assay was done on representative samples to validate the stemness of isolated cells. RNA was isolated from the isolated cell populations and microarray was done to study the whole genome transcriptomic changes. 4 x 44k Whole genome expression arrays of Isolated and Characterised colorectal Cancer stem cells (n=3), Cancer non stem cells (n=3), normal stem cells (n=3) and normal non-stem cells (n=3) total RNA obtained from colorectal cancers tissues and normal colon tissues.