Toll-like receptor 3 has been targeted in different
cancers for adjuvant
therapy. The
ligand-mediated effects of TLR-3 on
cancer cells are discordant. In the present work, we have addressed the hypothesis possibility of cell membrane-bound action of TLR-3 in
breast cancer to justify its pro-
tumor effect. TLR-3 was stimulated by
Poly (I:C) on the surface of human
breast cancer cells MCF-7 and MDA-MB-231 for up to 72 h. To check the cell survival and growth, thiazol blue tetrazolium
bromide (MTT) assay, apoptosis assay, and cell cycle analysis were carried out. For changes in the metastatic properties, in vitro colony formation assay, scratch-wound healing assay and adhesion assay were also done. Using real-time PCR and immunocytochemistry, expression of
E-cadherin, was studied. To determine the affect of cytoplasmic stimulation,
Poly (I:C) was delivered with
lipid transfection
reagent. The results of the aforesaid experiments showed that there was a gradual increase of cellular survivability, growth, and
metastasis after the cell surface stimulation of TLR-3 with
Poly (I:C). Interestingly,
E-cadherin expression was increased both at transcriptional and translational level. On the other hand, when
Poly (I:C) was delivered in the cytoplasm by
lipid transfecting medium, the cells survivability was decreased. For the first time, in the present work, we are convincingly reporting the functional evidence that TLR-3 induces cell survivability and
metastasis through cell surface. The present work may help for the proper understanding of the adjuvant
therapy of
breast cancer.