Molecular consequences of EMT silencing on pancreas cancer cell lines

Pancreatic cancer is known to spread rapidly and rarely detected in early stages. Not until quite advanced stages, no signs and symptoms are observed and in advanced stages, it is nearly impossible to remove the tumor. This type of cancer is known to be aggressive and migrate to different sections of the body quickly. If metastasis of pancreatic cancer could be stopped it would be possible to manage the tumor without searching for additional tumor spread and if this treatment could be combined with drug resistance decrease it could be used as a good treatment option for pancreas cancer. Epithelial to Mesenchymal Transition (EMT) is counted as one of the possible routes for initiating metastasis and drug resistance. Movement of epithelial cells is limited. Hence it must convert itself into a more motile cell type "mesenchymal" by using EMT pathways. In this study, important EMT transcription factors "Snail, Slug, and Twist" were silenced by short hairpin technology on different pancreas cancer (adenocarcinoma) cell lines, Panc-1, MIA PaCa-2, BxPc-3, AsPc-1. It was shown that this silencing causes the cell to turn back into the epithelial stage; being less mobile and invasive, having decreased stem cell characteristics. After these favorable results from gene silencing, AsPc-1, metastatic pancreas cancer cell line, was subjected to chemotherapeutic agents and drug resistance was evaluated. EMT downregulated AsPc-1 cells have shown less resistance to chemotherapeutics compared to the control group. Combinational therapy (both gene therapy and drug induction) is a rising trend for cancer. During this study, together with gene therapy small molecule inhibitors of EMT were used to enhance the effect of gene downregulation. EMT downregulated AsPc-1 cells were treated with two EMT inhibitors, SD-208 and CX-4945, to understand the cumulative effect of gene therapy and small molecule inhibitors on migration and invasion. The results have shown that it is possible to increase the effect of gene therapy by using chemical support but gene therapy is irreplaceable with small molecule inhibitors alone. Overall it was found that inhibition of EMT, either by gene therapy alone or with the enhancement by small molecules, is a good candidate for the treatment of pancreas cancer since it simultaneously minimize metastasis, stem cell properties and drug resistance.