Inhibitory effects of PAMAM nanoparticle-mediated 5-fluorouracil combined with microRNA-21 inhibitor on breast cancer cells growth in vitro

Abstract

Objective To study the effect of PAMAM-mediated 5-fluorouracil combined with miR-21 inhibitor gene therapy to suppress MCF-7 human breast cancer cell growth in vitro. Methods 5-Fu/PAMAM complex was prepared by dialysis method and then incubated with miR-21 inhibitor at room temperature. Transmission electronic microscopy (TEM) was performed to observe the morphology of the nanoparticles. The drug loading efficiency and encapsulation efficiency was determined by ultraviolet spectroscopy (UV). The transfection of PAMAM dendrimer was detected by flow cytometry. MTT assay was carried out to determine MCF-7 cell growth survival rate. Cell apoptosis was analyzed by flow-cytometry. Transwell assay was performed to detect invasion ability after MCF-7 cells treated with 5-Fu chemotherapy combined with miR-21 inhibitor gene therapy. Results The morphology of the complex was sphere observed under TEM. Encapsulation efficiency and loading efficiency of drug were (66. 21±4. 11)% and (31.77±0. 73)% , respectively. Flow cytometry revealed that 5-Fu/PAMAM transfection efficiency was (60.54 ±6. 97)%. 5-Fu combined with miR-21 inhibitor treatment significantly suppressed cell growth, and the survival rate was only (55. 85±3. 71)% on the 6th day of the observation period. The apoptosis rate in combined treatment group was (18. 32±2.42)% , dramatically higher than in control group (F=58. 326,P<0. 01). In combined treatment group, the number of invasion cells was only 18. 96 ±3. 14, suggesting the greatly decreased invasion ability of MCF-7 cells (F=16. 409,P < 0. 01). Conclusion PAMAM could effectively deliver miR-21 inhibitor and 5-Fu simultaneously, and combined therapy can suppress growth of MCF-7 cells effectively in vitro. Key words: Polyamide; 5-Fu; miR-21 inhibitor; Breast carcinoma