AIM: To investigate the impact of ultrasound-targeted microbubble destruction-mediated transfection of integrin subunit a3 (ITGA3) on the growth and epithelial-mesenchymal transition (EMT) of breast cancer. METHODS: The expression of ITGA3 in breast cancer and its association with prognosis were evaluated by GEPIA and The Cancer Genome Atlas (TCGA) websites. The breast cancer cell line (BT-549) was transfected with liposome- or UTMD-mediated ITGA3 overexpression plasmid, respectively. Cell morphology was observed by electron microscopy. Cell viability was analyzed by MTT assay. Cell migration was detected by the scratch assay. Cell invasion was measured in the transwell chamber assay. The expression of ITGA3, E-cadherin, N-cadherin, Vimentin, STAT3, CyclinD1, and PCNA was detected by western blot. The breast tumor xenograft model was established by subcutaneous tumor cell injection in nude mice, and expression of ITGA3, N-cadherin, and PCNA in xenograft tumors was assessed by immunohistochemistry. RESULTS: The expression of ITGA3 was significantly lower in breast cancer tissues than in normal tissues. Low expression of ITGA3 is associated with poor prognosis in breast cancer patients. UTMD increased the transfection rate of ITGA3. UTMD- and liposome-mediated ITGA3 transfection reduced cell viability, migration, and invasion in BT-549 cells. Ectopic expression of ITGA3 retarded tumor growth in mice. Mechanistically, Overexpression of ITGA3 regulates the expression of EMT-related genes (E-cadherin, N-cadherin, Vimentin) and STAT3 pathway-related factors (STAT3, CyclinD1, PCNA) in BT-549 cells. The regulatory effects of UTMD-mediated ITGA3 transfection on the above-mentioned biological characteristics were better than liposome-mediated ITGA3 transfection. CONCLUSION: UTMD-mediated ITGA3 transfection exerted significant inhibitory effects on the growth and EMT of breast cancer, providing new experimental evidence for the treatment of breast cancer.