OBJECTIVETo investigate if Ad-NK4 can enhance the chemosensitivity of human multiple myeloma RPMI 8226 cells to bortezomib(BOR).

METHODSThe cell-matrix adhesion test and PRMI 8226 cell-ECV 304 cell adhesion test were used to analyze the effect of Ad-NK4 on adhesion of RPMI 8226 cells; Western blot was used to detect the expression changes of adhesion and invasion-associated proteins MMP2, MMP3, MMP7 and VEGF; MTT assay was used to detect the effect of Ad-NK4 on proliferation of RPMI 8226 cells; the flow cytometry with PI staining was used to detect the effect of Ad-NK4 on cell apoptosis; the expression of cleaved caspase-3, BAX and BCL-2 was assayed by Western blot.

RESULTSThese 2 adhesion assays indicated that Ad-NK4 significantly inhibited the adhesion of human multiple myeloma RPMI 8226 cells. In addition, Erk and JAK/STAT pathway may be involved in the process. The expression level of MMP-2, MMP-3 and VEGF were decreased in Ad-NK4 group, compared with untreated or Ad-GFP group (P<0.05). However, the expression of MMP-7 protein in Ad-NK4 group was not significantly different from untreated or Ad-GFP group (P>0.05). The inhibitory rates of the proliferation in cells treatedly Ad-NK4 combined with BOR was significantly higher than that with BOR or Ad-NK4 alone. Similarly, Western blot indicated that the level of cleaved caspase-3 and BAX in cells treated with Ad-NK4 combined with BOR was significantly higher than BOR or Ad-NK4 alone, but BCL-2 protein expression was significantly lower. Meanwhile, the ratio of BAX/BCL-2 was increased.

CONCLUSIONAd-NK4 can enhance the chemosensitivity of human multiple myeloma RPMI 8226 cells to BOR,which is associated with increasing of both BAX/BCL-2 ratio and Caspase-3 activation.