Objective To explore the relationship between WWOX gene and attachment and adhesion of ovarian cancer. Methods The expression of WWOX mRNA was detected by RT-PCR, the expression of the WWOX protein was evaluated by western blot in WWOX-transfected PEO1 cells (H6, H7, H8 cell) and vector-transfected control cells (vec-1, vec-2 cell). Attachment assay was used to assess the adhesion of the tranafection in PEOI cells via culturing the cells on the pre-coated fibronectin wells. RNA interference (RNAi) was used to knockdown the endogenous expression of WWOX in the A2780 ovarian cancer cell line by liposome. Attachment assay was detected the adhesion to fibronectin after gene silencing. Restdts RT-PCR showed that expression of mRNA WWOX in exon9 was in all transfection cells (H6, H7, H8, vec-1, vec-2 cell ). Western blot showed that expression of WWOX protein was in the WWOX-transfected cells (H6, H7, H8 cell ), but not in the vector-transfected cells (vec-1, vec-2 cell ). Attachment assay showed that H6, H7, H8 cell (0.098±0.003, 0.091±0.004, 0.099±0.003) adhered more slowly to fibronectin than vec-1, vec-2 cell (0.185±0.003, 0.175±0.006) and non-transfected PEO1 cell (0.211±0.007), and demonstrated significantly reduced adhesion after 2 hours (P ＜ 0.01). A2780 adhesive cells that WWOX gene be knockdown was 0.059±0.005, adhered more significantly rapid than those untreated cells that was 0.029±0.003 after treated 30 minutes (P ＜ 0.05 ). Conclusions WWOX gene can suppress adhesion to fibronectin in ovarian cancer cells. This suggests an important role for loss of WWOX gene in promoting attachment and adhesion of ovarian cancer cells on loco-regional peritoneum, and further resulting in enhancing loco-regional peritoneal tumor invasiveness and spread.

OBJECTIVETo observe the effects of WWOX on cell attachment in ovarian cancer, and to explore its mechanisms of action.

METHODSAttachment assay was used to assess the adhesion of wwox-transfected PEO1 cells and vector-transfected PEO1 cells that were constructed, as well as PEO1 parent cells. Alpha/beta integrin-mediated cell adhesion assays were designed to identify cells surface integrins in PEO1 clone cells. Integrin function blocking experiments were designed to further determine integrins in PEO1 clone cells according to the integrin that was selected in integrin expression profiling. FACS analysis was used to further detect the level of integrin alpha3 on the cell membrane.

RESULTSAttachment assay showed that adhesion of WWOX-transfected PEO1 cells to fibronectin was significantly slower than that in vector-transfected controls or PEO1 parent cells, cultured on the pre-coated fibronectin for 2 hours (P<0.01). The level of membranous integrins alpha2 and alpha3 in the WWOX-transfected PEO1 cells was significantly decreased, as compared with that in vector-transfected controls (P<0.05), but there was no association with the level of functioning integrins betal or beta2 in clone cells (P>0.05). The attachment assays were repeated after pre-incubating the cells with integrin alpha2 or alpha3 function-blocking antibodies. These results showed that blocking integrin alpha3 significantly reduced the binding to fibronectin of all the PEO1 clonal lines, as compared with cells pre-incubated with a non-specific IgG antibody (P<0.05). In contrast, preincubation with alpha2 blocking antibody had very little effect on fibronectin binding in these cells (P>0.05). FACS analysis showed that membranous integrin alpha3 expression revealed a marked reduction in WWOX-transfected cells than that in vector-transfected cells.

CONCLUSIONWWOX acts as an ovarian tumor suppressor by modulating the interaction between tumor cells and the extracellular matrix, decreasing integrin activity and adhesion of tumor cells to fibronectin. This suggests an important role for loss of WWOX tumor suppressor in promoting attachment and adhesion of ovarian cancer cells on locoregional peritoneum, and further resulting in enhancing locoregional peritoneal tumor spread.

CD18 Antigens ; metabolism ; Cell Adhesion ; Female ; Fibronectins ; metabolism ; Humans ; Integrin alpha2 ; metabolism ; Integrin alpha3 ; metabolism ; Integrin beta1 ; metabolism ; Ovarian Neoplasms ; metabolism ; pathology ; Oxidoreductases ; genetics ; metabolism ; Protein Binding ; Transfection ; Tumor Suppressor Proteins ; genetics ; metabolism ; WW Domain-Containing Oxidoreductase