[GINS1 Enhances Glycolysis, Proliferation and Metastasis in Lung Adenocarcinoma Cells by Activating the Notch/PI3K/AKT/mTORC1 Signaling Pathway].

Background: Lung cancer is the most common type of cancer, accounting for more than half of all cancer cases, with lung adenocarcinoma (LUAD) representing over half of lung cancer patients. Currently, the 5-year survival rate for metastatic LUAD patients remains low and there is an urgent need for new biomarkers as targets for targeted therapy. Go-Ichi-Ni-San 1 (GINS1), an important member of the GINS family, is closely related to the occurrence and development of human malignant tumors. This study aims to explore the role of GINS1 in glycolysis, proliferation, and metastasis of LUAD cells and the related molecular mechanisms.

Methods: The expression of GINS1 was analysed using bioinformatics between LUAD patients and healthy controls. The expression levels of GINS1 in LUAD and adjacent tissues were detected by immunohistochemistry and Western blot. Western blot and real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) were used to detect the expression of GINS1 in LUAD cell lines A549, SK-LU-1, Calu-3, H1299 and BEAS-2B. Stably knockdown GINS1 in A549 cells and its negative control cell line, as well as stably overexpress GINS1 in H1299 cells and its negative control cell line, were constructed by lentiviral transduction. Colony formation test was used to detect cell proliferation. Scratch test was used to detect cell migration. Transwell test was used to detect cell invasion, and the test kits were used to detect glucose consumption and lactate production. The expression levels of glycolysis-related proteins, Notch signaling pathway proteins and phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway proteins were detected by Western blot. The Notch receptor agonist Jagged1 was added to cells from the shGINS1-A549 group and the Notch receptor inhibitor LY3039478 was added to cells from the GINS1-OE-H1299 group for the regression assay.

Results: The expression of GINS1 was up-regulated in LUAD patients, tissues and cell lines, and correlated with overall survival (P<0.05). Knockdown of GINS1 significantly inhibited the proliferation, migration and invasion of A549 cells (P<0.05), while overexpression of GINS1 significantly enhanced the proliferation, migration and invasion of H1299 cells (P<0.05). Furthermore, knockdown of GINS1 resulted in reduced glucose consumption, reduced lactate production, and reduced expression levels of glycolytic-related proteins in A549 cells (P<0.05); overexpression of GINS1 enhanced glycolytic level in H1299 cells (P<0.05). The expression levels of Notch1, Notch3, phosphorylated-PI3K (p-PI3K), phosphorylated-AKT (p-AKT) and phosphorylated-mTORC1 (Ser2448)[p-mTORC1 (Ser2448)] in A549 cells were significantly decreased by GINS1 knockdown (P<0.05), while the expression levels of PI3K, AKT, mTOR and p-mTORC2 (Ser2481) were not significantly changed (P>0.05). Overexpression of GINS1 increased the levels of Notch1, Notch3 and PI3K/AKT/mTORC1 pathway phosphorylated proteins in H1299 cells (P<0.05). Jagged1 significantly reversed the inhibition of glycolysis, proliferation and metastasis induced by GINS1 knockdown in A549 cells (P<0.05), and LY3039478 significantly inhibited the enhancement of glycolysis, proliferation and metastasis induced by GINS1 overexpression in H1299 cells (P<0.05).

Conclusions: The expression of GINS1 enhances the expression of Notch1 and Notch3 receptors, and then phosphorylates and activates the downstream PI3K/AKT/mTORC1 signaling pathway to enhance the glycolysis, proliferation and metastasis of LUAD cells.