AMP-activated protein kinase (AMPK) is required for recovery from metabolic stress induced by ultrasound microbubble treatment

Abstract

Ultrasound and microbubbles (USMB) is a promising strategy for cancer therapy. USMB can induce a variety of effects on cells including transient formation of plasma membrane pores (sonoporation) and enhanced endocytosis, which enhance drug delivery, and can also lead to enhanced cell death. However, the outcomes of USMB on cell physiology are heterogeneous, in that USMB elicits cell death in a proportion of cells while exerting minimal effects on others. This suggests that mechanisms of adaptation following USMB allow some cells to survive and/or proliferate. The molecular mechanisms of adaptation to USMB-induced stress remain poorly understood, thus potentially hindering broad therapeutic applications of USMB. Herein, we used several triple negative breast cancer cells to study the effect of USMB-induced metabolite stress and the role of AMPK as a response to this stress. We found that USMB alters steady-state levels of amino acids, glycolytic intermediates, and citric acid cycle intermediates. USMB treatment acutely reduces ATP levels and stimulates AMP-activated protein kinase (AMPK) phosphorylation and activation. Further, AMPK is required to restore ATP levels in cells that survived the initial insult and support cell proliferation post-USMB treatment. These results suggest that AMPK and metabolic perturbations are likely determinants of the anti-neoplastic efficacy of USMB treatment.

HER2 expression defines unique requirements for flotillin and c-Src for EGFR signaling

“…MDA-MB-231 and MDA-MB-231-HER2 cells were seeded on a 6 well plate and subjected to siRNA transfection as described. Immediately following the second round of transfection, cells were placed in the Incucyte SX5 and maintained at 37°C and 5% CO2 (Sartorius, Göttingen, Germany) for detection and automated analysis of cell growth/proliferation, as we described previously (Lo et al, 2022). The phase-contrast camera was used to take images every 30 min for 48 h. Time-lapse image series were analyzed using the Incucyte Basic Analysis Software.…”