MicroRNA-328 acts as an anti-oncogene by targeting ABCG2 in gastric carcinoma

To explore the regulatory mechanism of microRNA-328 expression level by targeting the protein ATP Binding Cassette Transporter G2 (ABCG2) in gastric cancer cells and seek for a biological marker of predicting gastric cancer.

SGC-7901 and MKN-28 human gastric cancer cell lines were cultured. Meanwhile, paired gastric cancer pathological tissues and the corresponding adjacent normal tissues were collected. Western blot analysis was used to validate the protein expression of ABCG2. Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) analysis was used to detect the mRNA expression level of miR-328 and ABCG2. Cell counting kit-8 (CCK-8) and colony formation assay were performed to validate the proliferous ability of human gastric cancer cells. The transwell invasion and migration were operated to determine the migratory and invasive capacity. Dual-Luciferase reporter assay, qRT-PCR and Western blot were used to prove the target of miR-328.

Bioinformatics analysis made a prediction that ABCG2 was a direct functional target of miR-328. Position 619-625 of ABCG2 3'-UTR had a space structure that was complementary to miR-328 by bioinformatics analysis, and there was a significant reduction in the level of miR-328 in human gastric cancer cell lines and tissues. The expression of miR-328 down-regulated proliferation, invasion and migration of human gastric cancer cells in vitro, while silencing of miR-328 accelerated proliferation, invasion and migration of human gastric cancer cells in vitro. All results displayed ABCG2 was direct target protein of miR-328 owing the binding site and they presented a negative correlation.

ABCG2 is the target protein of miR-328. It presents a negative correlation of the expression level between miR-328 and ABCG2. Down-regulation of miR-328 inhibits the proliferation, invasion and migration of gastric cancer cell lines. MiR-328 could predict generation and development of gastric cancer as a biomarker.