Ruxolitinib-loaded poly-ɛ-caprolactone (PCL) nanoparticles inhibit the JAK2/STAT5 signaling via downregulating Bcl-2 and Mcl-1 on BT474 breast cancer cells

Abstract

Background: To regulate proliferation, JAK/STAT signaling is important. Reducing proliferation and inducing cell death with gene-specific inhibitors such as Ruxolitinib, an RTK inhibitor targeting JAK1/2, are therapeutic approaches. The use of nanoparticles can reduce the toxic and side effects of drugs, as they act directly on cancer cells, and can selectively increase drug accumulation in tumor cells. PCL is a polymer that is frequently used in drug development. This study aimed to increase the effectiveness of Ruxolitinib in BT474 cells by synthesizing Rux-PCL-NPs and to understand the effect of JAK/STAT and apoptotic cell death in cells. Methods and Results: Rux-PCL-NPs synthesized by nanoprecipitation. Moreover, Rux-PCL-NPs have a spherical and mean particle size of 219 - 88.6 nm, and a zeta potency of 0.471 - 0.453 mV. In vitro cytotoxicity and anti-proliferative effects were determined by MTT and Soft Agar Colony Formation assay, respectively. The effects of Ruxolitinib, PCL-NPs, and Rux-PCL-NPs on apoptosis and JAK/STAT pathways in cells were examined by western blot assay. PCL-NPs didn’t have a toxic effect on the cells. IC50 values of Ruxolitinib decreased 50-fold with the nanoform of Ruxolitinib. By inhibiting the JAK/STAT pathway by reducing JAK2 and STAT5 expression, Rux-PCL-NPs promote cell death. Conclusions: Our results revealed the roles of Ruxolitinib, increased drug efficiency with Rux-PCL-NPs, on regulating apoptosis and JAK2/STAT5 pathways. Rux-PCL-NPs can be used to increase the drug efficacy of Ruxolitinib.