Circular RNA LDLRAD3 promotes gastric cancer progression by upregulating COL4A5 through sponging miR-h37.

[BACKGROUND] Circular RNAs play an important role in the development of gastric cancer (GC). circ-low-density lipoprotein receptor class A domain containing 3 (LDLRAD3) has been confirmed to be related to GC progression. miR-137 is also a suppressor in GC. However, the impact of the interaction between circ-LDLRAD3 and miR-137 on the progression of GC remains unclear at present.

[METHODS] The study identified expression level differences of circ-LDLRAD3, miR-137, and COL4A5 in GC pathological specimens compared to normal tissue samples. Furthermore, through in vitro experiments, including flow cytometry, cell counting kit-8 (CCK-8) assays, wound healing, Western blotting, and colony formation assays, we further explored the molecular regulatory mechanisms by which these factors promote the progression of GC.

[RESULTS] In this study, circ-LDLRAD3 was confirmed to have higher expression, and miR-137 had lower expression in GC tissues and cell lines. circ-LDLRAD3 knockdown and miR-137 overexpression promoted apoptosis and inhibited proliferation, migration, and invasion in GC cell lines. Further experiments validated that COL4A5 had a positive relationship with GC and that circ-LDLRAD3 promoted the expression of COL4A5. circ-LDLRAD3 could be sponged and inhibited by miR-137 in GC cells. As a result, the promotional effect of circ-LDLRAD3 on COL4A5 was counteracted by miR-137.

[CONCLUSION] Our study showed that the knockdown of circ-LDLRAD3 suppressed the development of GC by regulating the miR-137/COL4A5 axis.