Anticancer activity and modulation of gene expression by thymoquinone conjugated ZnO nanoparticles in Triple Negative Breast Cancer cell line MDA MB 231

Abstract

The aim of the present work is to analyze the anticancer activity of the thymoquinone conjugated ZnO nanoparticles and also to understand its mechanism of action in triple negative breast cancer cell line MDA-MB-231. The current work was carried out in four different phases. In phase I, Zinc Oxide and thymoquinone conjugated ZnO nanoparticles were synthesized using simple precipitation method and the synthesized nanoparticles were characterized by various spectroscopic methods such as UV-Visible spectroscopy, FTIR spectroscopy, XRD, Zeta potential, Dynamic Light Scattering, FESEM with EDS and elemental mapping. In the second phase of the study, loading and encapsulation efficiency and drug releasing profile were assessed. In the third phase, dose and time were optimized for the exposure of TNBC cells to ZnO nanoparticles, thymoquinone and thymoquinone conjugated ZnO nanoparticles. Anti-proliferative and anti-migratory effect was analyzed using colony forming and cell migration assay respectively. Mechanism of cytotoxicity induced cell death was measured by flow cytometry. The anticancer activity of the thymoquinone was assessed by analyzing the loss of mitochondrial potential, production of ROS, ER stress mediated cell death and the stages of cell cycle arrest were analyzed using flow cytometry. In Phase IV, the gene expression profile of 84 genes which are related to breast cancer progression was studied using Breast Cancer Real Time PCR array against the triple negative breast cancer cell line. The results of phase I, showed that the particles synthesized were ZnO and thymoquinone conjugated ZnO nanoparticles and they are highly stable, crystalline in nature, spherical in shape and monodispersive without agglomeration and the surfactant PEG helped thymoquinone to attach firmly on the surface of the synthesized ZnO nanoparticles. From the results of phase II, it clearly revealed that the maximum amount of thymoquinone was released in the acidic pH 5.5 which corresponds to tumor environment.