Suppression of PANC-1 pancreatic cancer cell proliferation by gemcitabine and ultrasound-mediated microbubble therapy

Pancreatic ductal adenocarcinoma (PDAC) is among the most treatment-resistant malignancies, characterized by aggressive progression and limited drug penetration reducing chemotherapeutic efficacy. Gemcitabine, a pyrimidine nucleoside analog and standard-of-care therapy for PDAC, remains clinically important but is limited by the emergence of resistant tumor cell populations that underscore the need for strategies that enhance cytotoxic efficacy and overcome adaptive resistance mechanisms. Ultrasound-stimulated microbubble (USMB) therapy has emerged as a noninvasive, mechanically driven approach capable of transiently perturbing cellular membranes and enhancing therapeutic responses. We hypothesized that gemcitabine-induced metabolic and structural alterations may sensitize PDAC cells to subsequent disruption by USMB, resulting in enhanced cell death. To test this hypothesis, we assessed changes in proliferation, morphology, and cell death following gemcitabine and USMB treatments administered individually and in sequence to PANC-1 cells. Gemcitabine treatment alone (2 µM for 48h) significantly reduced cell proliferation by approximately 22% and induced pronounced morphological remodeling, including statistically increased average cell diameter from ∼19 µm to ∼22 µm, consistent with cytoplasmic expansion and structural reorganization. Notably, when gemcitabine-treated cells were subsequently exposed to USMB (1 MHz, 770 kPa negative pressure for 1 min), cell death increased dramatically to >80%, significantly exceeding the effects observed with either gemcitabine or USMB monotherapy indicating that gemcitabine pretreatment induces a mechanically vulnerable cellular state that can be exploited by USMB to achieve synergistic cytotoxicity. Therefore, the proposed combined biochemical-biophysical strategy offers a promising approach to suppress the rapid compensatory growth and therapeutic resistance commonly associated with monotherapy failure in PDAC cells.