ALKBH5-dependent upregulation of circARHGEF12 impairs gastric cancer progression and cisplatin resistance by regulating miR-130b-5p/LATS2 signaling

<title>Abstract</title> <p> Background Accumulating evidence unveils that N6-methyladenosine (m ⁶ A) methylation modifications and deregulated circular RNAs (circRNAs) play critical roles in diverse malignancies including gastric cancer (GC). Nevertheless, the molecular mechanism by which the m ⁶ A demethylase ALKBH5 mediates circRNA m ⁶ A modification to govern GC progression remains largely uncharacterized. Methods An m ⁶ A-circRNA epitranscriptomic microarray was performed to identify ALKBH5-mediated m ⁶ A demethylation of hsa_circ_0002089 (circARHGEF12) in GC, which was verified by m ⁶ A dot blot, RT-qPCR, methylated RNA immunoprecipitation (Me-RIP) and RIP assays. The cellular localization and mRNA expression levels of circARHGEF12 in GC tissue samples were detected by fluorescence in situ hybridization. Gain- or loss-of-function assays as well as <italic>in vivo</italic> tumorigenesis and lung metastasis models were executed to assess the role of circARHGEF12 in GC cells. The specific binding of circARHGEF12 with miR-130b-5p was validated by RT-qPCR, RIP, and luciferase gene report assays. The effects of Oridonin-mediated ALKBH5 and (or) circARHGEF12 on LATS2/YAP signaling were determined by RT-qPCR, Western blot and functional assays. Results Microarray and molecular validation results confirmed that circARHGEF12 served as a direct m ⁶ A target of ALKBH5 in GC cells. Functional experiments demonstrated that ectopic overexpression of circARHGEF12 suppressed tumorigenesis, metastatic progression and cisplatin resistance in GC both <italic>in vitro</italic> and <italic>in vivo</italic> , while circARHGEF12 knockdown exerted the opposite oncogenic effects. Mechanistically, circARHGEF12 functioned as a competing endogenous RNA to sponge miR-130b-5p and thereby upregulated the expression of downstream LATS2. Moreover, oridonin was verified to elevate ALKBH5 expression to strengthen the anti-tumor effects through the circARHGEF12/miR-130b-5p/LATS2 signaling in GC. Conclusions ALKBH5-dependent upregulation of circARHGEF12 impairs GC progression and cisplatin resistance by modulating the miR-130b-5p/LATS2 signaling. These findings provide a novel mechanistic insight into the m ⁶ A-mediated regulatory network of GC malignancy and identify circARHGEF12 as a promising therapeutic target for GC. </p>