Figure 3

MSC/Adv-Stat3(-) selectively exerts in vitro oncolytic effects on breast cancer and melanoma cell lines and suppresses the Stat3 pathway. (A) Cytopathic effects and virus replication induced by MSC and MSC/Adv-Stat3(-) in MDA-MB-231, MDA-MB-435, and HUVEC cells. 1 × 10⁵ MDA-MB-231, MDA-MB-435, and HUVEC cells were plated in the lower chambers of transwell plates. 1 × 10⁴ MSCs pre-infected with 500 MOI Adv-Stat3(-) for 48 hours or MSCs alone were added in the upper chambers. Phase contrast images of the cells in the lower chamber were taken after 72 hours and in situ hybridizations targeting viral fiber were performed. Scale bar = 10 μm. Cell nucleuses were counterstained with DAPI. (B) Apoptosis rates caused by MSC, Adv-Stat3(-), and MSC/Adv-Stat3(-) in MDA-MB-231, MDA-MB-435, and HUVEC cells. 1 × 10⁵ MDA-MB-231, MDA-MB-435, and HUVEC cells were plated in the lower chambers of transwell plates. 1 × 10⁴ MSCs pre-infected with 500 MOI Adv-Stat3(-) for 48 hours, equivalent Adv-Stat3(-), or MSCs were added in the upper chambers. The cells in the lower chambers were stained with Annexin-V/PI after 72 hours and analyzed by FACS. (C) Apoptosis in the lower chambers in response to different ratios of MSC/Adv-Stat3(-). (D) Representative Western blot demonstrating the changes in Stat3, p-Stat3, Bcl-xl, c-myc, and Survivin caused by MSC/Adv-Stat3(-), Adv-Stat3(-), and MSC. Medium was used as a negative control. *P < .05. Results were expressed as mean ± SD in three independent experiments.