Autophagic blockage by metformin-loaded PLGA nanoparticles causes cell cycle arrest of HepG2 cells

Aim: To fabricate and characterize metformin-loaded PLGA nanoparticles and investigate their inhibitory effect on HepG2 cells. Materials & methods: The nanoparticles were prepared using a double emulsification method, then characterized and subjected to a series of in vitro assays on HepG2 cells. Results: The nanoparticles were ~277.9 nm in size, and the entrapment efficiency and drug loading of metformin were 31.3 and 14.4%, respectively. In vitro studies suggested that the nanoparticles showed a higher inhibitory effect on HepG2 cells compared with metformin alone, mainly attributed to its blockage of autophagy, and ultimately result in cell cycle inhibition. Conclusion: The metformin-loaded PLGA nanoparticles could inhibit mTOR activity, increase p53 levels and decrease HIF1A levels, which ultimately caused HepG2 cell cycle arrest.