Inhibitory effect of docetaxel combined with oncolytic adenovirus carrying short hairpin RNA targeting special AT rich sequence binding protein-1 on proliferation and invasion of breast cancer MDA-MB-231 cells

Abstract

Objective To investigate the effect of docetaxel and oncolytic adenovirus carrying short hairpin RNA (shRNA) targeting special AT rich sequence binding protein-1 (SATB1) (ZD55-SATB1) on the proliferation and invasion of breast cancer MDA-MB-231 cells. Methods MDA-MB-231 cells were divided to 5 groups and treated with phosphate buffer (PBS), docetaxel (DOC, 1×10-6 mol/L), ZD55-enhanced green fluorescent protein (EGFP) (10 multiplicity of infection, MOI), ZD55-SATB1 (10 MOI), ZD55-SATB1 plus DOC (10 MOI + 1×10-6 mol/L) respectively. The viability of MDA-MB-231 cells treated with DOC (1×10-9, 1×10-8, 1×10-7, 1×10-6, 1×10-5 mol/L) alone and ZD55-SATB1 (0, 0.1, 1.0, 10.0, 100.0 MOI) alone for 96 h was assessed by cell counting kit-8 (CCK-8) assay. And the viability of MDA-MB-231 cells of 5 groups with 48-h treatment was assessed by CCK-8 assay. Cell invasion and migration capacities of MDA-MB-231 cells were detected by Transwell assay and Wound-Healing Assay respectively. The expression of E1A, SATB1 and invasion associated protein matrix metalloproteinase (MMP)-2, Vimentin, DE-cadherinF in MDA-MB-231 cells was detected by Western blotting. Results CCK-8 assay showed that DZD55-SATB1F (10 MOI) plus DOC (1×10-6 mol/L) (35.16±2.17)%, compared with corresponding dose ZD55-SATB1 (10 MOI) (58.26±2.02)% (P=0.015), ZD55-EGFP (10 MOI) (71.25±3.49)% (P=0.023), DOC (1×10-6 mol/L) (50.16±3.17)% (P=0.018), could significantly inhibit the viability of MDA-MB-231 cells after 48 h. Wound-healing assay showed that ZD55-SATB1 plus DOC could significantly inhibit the ability of cell migration as compared with ZD55-SATB1 group, ZD55-EGFP group or DOC group. Transwell assay showed the number of transmembrane cells in combination group (356.2±101.5), produced obvious inhibition of cell invasion and migration capacity of the MDA-MB-231 cells as compared with ZD55-SATB1 group (576.1±89.4) (P=0.035), ZD55-EGFP group (935.2±201.3) (P=0.027) and DOC group (878.4±178.7) (P=0.016), and the difference was significant. Western blotting showed that the adenovirus ZD55-SATB1 and ZD55-EGFP were efficient replication in MDA-MB-231 cells and DOC had no effect on adenovirus replication. In addition, SATB1 expression in the ZD55-SATB1 plus DOC group was lower than PBS group, DOC group, ZD55-SATB1 group and ZD55-EGFP group. Western blotting analysis also confirmed that ZD55-SATB1 plus DOC could increase the expression level of E-cadherin, concomitant with down-regulating the protein expression of MMP-2, Vimentin (P=0.000). Conclusion Oncolytic adenovirus carrying shRNA targeting SATB1 gene could inhibit the growth and invasion of MDA-MB-231 cells. The combined use of ZD55-SATB1 with DOC could significantly inhibit the proliferation and invasion of MDA-MB-231 cells. And the combination of the treatment of oncolytic adenovirus and DOC is better than DOC or adenovirus alone. Key words: Special AT rich sequence binding protein-1; Breast cancer; Docetaxel; Invasion; Migration