Upregulation of miR-133a-3p enhances Bufothionine-induced gastric cancer cell death by modulating IGF1R/PI3K/Akt signal pathway mediated ER stress.

ABSTRACT

AIMS: Bufothionine had been used for gastric cancer (GC) treatment, and this study managed to uncover the underlying mechanisms. MATERIALS AND METHODS: Cell proliferation was determined by CCK-8 assay and colony formation assay. Flow cytometry (FCM) and TUNEL assay were used to measure cell apoptosis ratio. Intracellular ROS was measured by DCFH-DA probes. qRT-PCR was used to determine miRNAs levels. Western Blot was performed to probe proteins. Dual-luciferase reporter gene system was employed to validate the binding sites of miR-133a-3p and 3'UTR regions of IGF1R mRNA. Immunohistochemistry (IHC) was used to determine the expressions of Ki-67 in mice tumor tissues. KEY FINDINGS: Bufothionine inhibited cell viability, triggered ER stress and promoted ROS production in GC cells, and both ER stress inhibitor Salburinal (Sal) and ROS scavenger (NAC) abrogated Bufothionine induced GC cell death. Besides, miR-133a-3p was upregulated by Bufothionine, and Bufothionine-induced cell death was enhanced by miR-133a-3p overexpression while alleviated by miR-133a-3p knockdown. Furthermore, miR-133a-3p inactivated PI3K/Akt signal pathway by sponging IGF1R, and Bufothionine inhibited insulin-like growth factor 1 receptor (IGF1R) and inactivated PI3K/Akt cascade by upregulating miR-133a-3p. Notably, the promoting effects of overexpressed miR-133a-3p on Bufothionine-induced GC cell death were abrogated by overexpressing IGF1R, and aggravated by the PI3K/Akt cascade inhibitor (LY294002). SIGNIFICANCE: Bufothionine promoted GC cell death by triggering miR-133a-3p/IGF1R/PI3K/Akt axis mediated ER stress and ROS production.