Anoikis-suppression and invasion induced by tyrosine kinase receptor B in OVCAR3 ovarian cancer cells

Abstract

To study the relationship between tyrosine kinase receptor B (TrkB) expression and anoikis-suppression and invasion in OVCAR3 ovarian cancer cells. The expression of TrkB mRNA in OVCAR3 ovarian cancer cells under two culture conditions: adhesive cells and cell-spheroids were evaluated by RT-PCR and real-time PCR. The relationship between TrkB expression and anoikis-suppression of OVCAR3 ovarian cancer cells was examined by RNA interference (RNAi) technic, anchorage independent culture and fluorescence-activated cell sorting analysis. The difference in invasion and metastatic ability of OVCAR3 cells under two culture conditions and with or without TrkB silenced by small interfering RNA (siRNA) was investigated by matrigel invasion assay and in vivo studies. The expression of TrkB mRNA was highest in OVCAR3 ovarian cancer cells, 0.0240 +/- 0.0017, compared with the other three cell lines, 0.0030 +/- 0.0006, 0.0027 +/- 0.0009 and 0.0087 +/- 0.0003 respectively, and the expression in OVCAR3 multicellular spheroids was significantly higher than that in cells under monolayer adhesive culture, 0.0437 +/- 0.0021 versus 0.0240 +/- 0.0017 (P < 0.01). TrkB mediated anoikis-suppression in OVCAR3 ovarian cancer cells. OVCAR3 multicellular spheroids had a higher invasion ability than OVCAR3 cells under monolayer adhesive culture, and the penetrating cells of the two groups were 71.8 +/- 0.8 and 47.7 +/- 0.8 respectively (P < 0.01). The metastatic ability of OVCAR3 cells was attenuated when TrkB was silenced, and the volume of the tumors developed by OVCAR3 adhesive cells and OVCAR3 adhesive cells with TrkB silenced were (16.3 +/- 4.7) mm(3) and (6.0 +/- 1.4) mm(3) respectively (P < 0.01). As an anoikis-suppressor, TrkB may increase the invasion and metastasis of OVCAR3 ovarian cancer cells.