TiO2 nanoparticles induce the blockage of autophagy and sensitize gastric AGS cells to 5-fluorouracil

IntroductionAutophagy-modulating nanoparticles (NPs) have been recently promised to increase the efficacy of current therapeutic options for the treatment of cancer. However, the exact molecular mechanisms by which NPs harness an autophagic response still needs to be unravel. Here, we aimed to investigate autophagic effects of TiO2 NPs for sensitizing gastric AGS cells to chemotherapy.MethodsThe development of acidic vesicular organelles (AVOs) were studied by fluorescent microscopy using acridine orange staining. The gene and protein expression levels of apoptotic and autophagic markers (ie., Bax, Bcl2, ATGs, p62/SQSTM1 and LC3II) were analyzed by real-time PCR and western blotting, respectively. Apoptosis was examined by flow cytometric analysis of sub-G1 cell-cycle population. Results TiO2 NPs by itself induced AVO formation, LC3II conversion and p62 accumulation, suggesting the occurrence of an autophagy blockage response. Similarly, treatment with 5-fluorouracil (5-FU) stimulated the formation of AVO and LC3II but disappeared the protein levels of p62, displaying the induction of an autophagic flux response. The combination of TiO2 NPs and 5-FU resulted in higher increase at the levels of autophagy an apoptosis compared to each monotherapy. Using an early inhibitor of autophagy, 3-methyladenine, we showed that autophagy is the upstream for combination therapy effects.ConclusionAdding TiO2 NPs enhanced the cytotoxic effects of 5-FU in AGS cells via autophagy blockage, suggest that the autophagic potential of NPs can be utilized for sensitizing AGS cells to chemotherapy.

کلیدواژه ها:

5-fluorouracil ، autophagy ، chemotherapy ، gastric cancer ، nanoparticle ، titanium dioxide