Kindlin-2 promotes invasiveness of prostate cancer cells via NF-κB-dependent upregulation of matrix metalloproteinases.

Invasive progression is the major lethal cause of prostate cancer. In this study, we aimed to investigate the role of kindlin-2, an integrin-binding focal adhesion protein, in the regulation of invasiveness of prostate cancer. We found that downregulation of kindlin-2 using small interfering RNA (siRNA) technology significantly inhibited the invasion of PC-3 and DU-145 prostate cancer cells in a Matrigel Transwell assay. Conversely, overexpression of kindlin-2 promoted the invasiveness of prostate cancer cells. Kindlin-2 overexpression was found to activate nuclear factor (NF)-κB-dependent signaling and upregulate the expression of matrix metalloproteinase-9 (MMP-9) and MMP-2, whereas kindlin-2 silencing led to opposing effects on the expression of NF-κB and MMPs. Most importantly, kindlin-2-induced invasiveness was almost completely abolished by pretreatment with pyrrolidine dithiocarbamate (an inhibitor of NF-κB signaling) or co-transfection with MMP-9 or MMP-2 siRNA. Taken together, our data indicate that kindlin-2 promotes the invasiveness of prostate cancer cells largely through NF-κB-dependent upregulation of MMP-9 and MMP-2. Further studies are warranted to evaluate the significance of kindlin-2 as a therapeutic target for metastatic prostate cancer.

[Effects of adenovirus-mediated PTEN on the proliferation of prostate cancer PC-3 cells and expressions of cyclin D1 and p21].

OBJECTIVE: To construct a recombinant adenovirus expression vector containing the anti-oncogene PTEN and to investigate the effects of the PTEN gene on the proliferation of prostate cancer PC-3 cells and the expressions of cyclin D1 and p21 in the PC-3 cells. METHODS: The PTEN gene was amplified from the rat hippocampus by RT-PCR and cloned into the shuttle plasmid pEN-TR2A. The plasmids were constructed and amplified in 293A cells. Prostate cancer PC-3 cells were cultured in vitro and infected with the adenoviral vector carrying the PTEN gene (Ad-PTEN). The up-regulation of the PTEN protein was measured by indirect immuno-fluorescence assay; the expressions of PTEN, cyclin D1 and p21 in the cells infected with Ad-PTEN and Ad-LacZ were determined by RESULTS: The Western blot; and the effect of PTEN on the cell proliferation was detected by MTT assay and plate colony formation. recombinant adenoviral vector Ad-PTEN was successfully constructed. Western blot showed a significantly increased expression of the PTEN protein in the PC-3 cells infected with Ad-PTIEN (0.215 +/-0.065) as compared with that in the control ([0.052 +/-0.009], t = 4. 30, P <0.05) and the Ad-LacZ group ( [0. 056 +/- 0.008 ] , t =4.21, P <0.05). The expression of cyclin D1 was significantly lower in the Ad-PTEN-infected PC-3 cells (0. 256 +/- 0. 072) than in the control ( [0. 502 +/- 0. 087 ], t = 3.77, P < 0.05) and the Ad-LacZ group ([0.498 +/-0.081] , t =3.87, P <0.05), while the expression of p21 remarkably higher in the Ad-PTEN-infected PC-3 cells (0.589 +/-0. 076) than in the control ([0. 146 +/-0.026] , t = 9.55, P<0. 01) and the Ad-LacZ group ([0. 163 +/-0. 024] , t = 9.26, P <0.01). Ad-PTEN significantly inhibited the growth of the PC-3 cells (21.98%) at 48 h (t = 6.80, P <0.01). The colony formation rate of the PC-3 cells was (37.4 +/-4. 18)% in the Ad-PTEN group, significantly lower than (54.9 +/-4.81)% in the control (t =4.76, P<0.01) and (56.5 +/- 5.42)% in the Ad-LacZ group (t=4.83, P<0.01). CONCLUSION: The expression of PTEN induced by Ad-PTEN can significantly inhibit the proliferation of PC-3 cells, down-regulate the expression of cyclin D1, and up-regulate the expression of p21.