Abstract

TGF-β is a secreted multifunctional protein that regulates propagation, differentiation, and distinct roles in various cell types. Most cell types synthesize the three isoforms of TGF-β1-3 in excess but rate-limiting step is their activation. Once activated TGF-β has strong growth inhibitory effects on epithelial and lymphoid cells. Activation of TGF-β requires proteases such as Furin as well as extracellular matrix proteins such as thrombospondin-1 (THBS1) and integrins. Most of the solid tumors arise from epithelial cells where tumor suppressor activities of TGF-β signaling dominate through growth inhibition. Paradoxically, in advanced cancers, tumor suppressive activity of TGF-β is lost. Abnormally high levels of TGF-β are produced, but cells develop resistance to TGF-β mediated growth arrest, allowing the pro-tumorigenic functions of TGF-β to dominate. In general, cancer cell lines which have lost the cytostatic response to TGF-β1 often express high levels of latent TGF-β.Inhibition of latent TGF-β by RNAi has been reported to activate the latent TGF-β processing proteins (Furin and Thrombospondin-1) which promote the maturation of TGF-β and resulting in apoptosis. Some of the cancer cell lines are hard to transfect using conventional transfection techniques, so to overcome this obstacle we are using natural delivery nano-particles exosomes which are small, extracellular, endosomal membrane derived, lipid bilayer membrane vesicles (30-100nm) released by fusion of multivesicular bodies with the plasma membrane. Exosomes can carry a variety of cargo including miRNA, mRNA, long non-coding RNA (lncRNA), In this project, we aim to establish a stable cell line using HEK293T cells that constitutively expresses siTGF-β. Exosomes isolated from this stable cell line can be used to transfect different cancerous cell lines to verify the knockdown of TGF-β and, restoration of TGF-β mediated cytotoxicity.

Committee Members:

• Dr. Muhammad Afzal Dogar
• Dr. Muhammad Shoaib