OVEREXPRESSION/KNOCKDOWN OF ADAPTOR PROTEIN Ruk/CIN85 IN HUMAN LUNG ADENOCARCINOMA A549 CELLS RESULTS IN OPPOSITE CHANGES BETWEEN MMP-2/MMP-9 EXPRESSION LEVELS/ACTIVITIES AND CELL`S INVASION

Aim. To investigate the changes in MMPs expression and activity as well as invasiveness of human lung adenocarcinoma A549 cells with up-/down-regulation of Ruk/CIN85. Methods. There were used A549 cells with stable overexpression (subline RukUp) and knockdown of Ruk/CIN85 (subline RukDown), as well as corresponding vector control sublines Mock and Scr. Cells were cultured in the complete DMEM medium under standard conditions. mRNA expression levels were estimated by RT2-PCR, enzymatic activity was assessed using gelatin zymography. Invasiveness of cancer cells was studied using Boyden chambers coated with Matrigel. Results. Analysis of mRNA expression of MMPs in RukUp and RukDown cells revealed that MMP-2 and MMP-9 were preferentially overexpressed in RukDown cells, while RukUp subline did not exhibit significant difference compared with corresponding control. These findings were confirmed and complemented by study of enzyme activities. The gelatinolytic activities of both MMP-2 and MMP-9 were dramatically increased in RukDown subline, compared to respective control. we revealed that MMPs regulation was inversely correlated with invasion potential of Ruk/CIN85 up/down A549 cells. In particular, it was established that invasiveness of RukUp cells was 2 times higher in comparison with respective control subline. Alternatively, invasion ratio was significantly decreased in RukDown cells (0,5 times) in comparison with control. Conclusions. According to the data received, it is possible to suggest that up-regulation of adaptor protein Ruk/CIN85 in A549 cells can lead to the very aggressive MMP-independent mode of migration that rely on cycles of expansion and contraction of the cell body mediated by the cortically localized actin and myosin.