Study on the effect of a triple cancer treatment of propolis, thermal cycling-hyperthermia, and low-intensity ultrasound on PANC-1 cells

BackgroundPancreatic cancer is a deadly cancer around the world. To reduce side effects and enhance treatment efficacy, study on combination therapy for pancreatic cancer has gained much attention in recent years. MethodsIn this paper, we propose a novel triple treatment combining propolis and two physical stimuli-thermal cycling-hyperthermia (TC-HT) and low-intensity ultrasound (US) on a human pancreatic cancer cell line PANC-1. MTT assay was used to determine the viability of PANC-1 cells. Flow cytometry was used to detect apoptosis, mitochondrial membrane potential (MMP) loss, and intracellular reactive oxygen species (ROS) levels. Western blot analysis was further performed to measure protein expression and phosphorylation. ResultsThe experiments found that, after the triple treatment, the cell viability of the PANC-1 cells decreased to a level 80% less than the control, without affecting the normal pancreatic cells. Another result was excessive accumulation of ROS after the triple treatment, leading to the amplification of apoptotic pathway through the mitogen-activated protein kinase (MAPK) family and mitochondrial dysfunction. Moreover, the combination of TC-HT and US also promotes the anticancer effect of the heat-sensitive chemotherapy drug cisplatin on PANC-1 cells. ConclusionThis study, to the best of our knowledge, is the first attempt to combine TC-HT, US and a nature compound in cancer treatment. We demonstrate that physical stimuli could augment the therapeutical effect of anticancer agents. It is expected that optimized parameters for different agents and different types of cancer will expand the methodology on oncological therapy in a safe manner.