Microbubble-Mediated Cavitation Promotes Apoptosis and Suppresses Invasion in AsPC-1 Cells

Abstract

The aim of this study was to identify the potential and mechanisms of microbubble-mediated cavitation in promoting apoptosis and suppressing invasion in cancer cells. AsPC-1 cells were used and divided into four groups: control group, microbubble-only (MB) group, ultrasound-only (US) group and ultrasound plus microbubble (US + MB) group. Pulse ultrasound was used at a frequency of 360 kHz and a SPPA (spatial peak, pulse average) intensity of 1.4 W/cm² for 1 min (duty rate = 50%). Then cells in the four groups were cultured for 24 h. Cell Counting Kit‑8 (Biosharp, Hefei, Anhui, China) revealed decreased cell viability in the US + MB group. Western blot confirmed that there were increased cleaved caspase‑3 and Bcl-2-associated X protein levels and decreased B‑cell lymphoma‑2 (Bcl-2) levels, as well as increased intracellular calcium ions and downregulated cleaved caspase-8, in the US + MB group. With respect to proliferation, cells in the US + MB group had lower expression of Ki67 and the weakened colony formation ability. The transwell invasion assay revealed that invasion ability could be decreased in AsPC-1 cells in the US + MB group. Further, it was found that cells in the US + MB group had lower levels of hypoxia-inducible factor-1α (HIF-1α) and vimentin and higher levels of E-cadherin compared with the other three groups. Finally, the US + MB cells had less invadopodium formation. In conclusion, these results suggest that microbubble-mediated cavitation promotes apoptosis and suppresses invasion in AsPC-1 cells.

Keywords: Apoptosis, Invasion; Cavitation; Pancreatic cancer; Ultrasound.