Rapamycin inhibits proliferation and induces autophagy in human neuroblastoma cells

Objective To investigate the effect of Rapamycin on proliferation and autophagy in human neuroblastoma (NB) cell lines and to elucidate the possible mechanism. Methods NB cells were treated with different concentrations of Rapamycin. Cell counting kit-8 (CCK-8) was used to measure proliferation, and flow cytometry (FCM) was used to analyze the cell cycle. EM was used to observe cell morphological changes. Western blotting (WB) was performed to detect the expression of Beclin-1, LC3-I/II, P62, mammalian target of Rapamycin (mTOR), and p-mTOR. Results Rapamycin inhibited the spread of NB cells in a dose- and time-dependent manner and arrested the cell cycle at the G₀/G₁ phase. EM showed autophagosomes in NB cells treated with Rapamycin. The WB results showed that the expression levels of Beclin-1 and LC3-II/LC3-I were significantly elevated in NB cells treated with Rapamycin, while the expression levels of P62, mTOR, and p-mTOR proteins were significantly reduced compared with the control cells (P<0.05). Conclusion Rapamycin inhibits cell proliferation and induces autophagy in human NB cell lines. The mechanism may be related to suppression of the mTOR signaling pathway.