Background/Abstract: PD-L1 has been an important target of cancer immunotherapy. We have showed that in human gastric cancer tissues, over-expression of PD-L1 was significantly associated with cancer progression and patients’ postoperative prognoses. However, as of now, how PD-L1 regulates the biological function of gastric cancer cells still remains elusive. Methods: We constructed the stable PD-L1 knockdown expression gastric cancer cell lines by using RNAi method, and further investigated the changes of biological functions including cell viability, migration, invasion, cell cycle, apoptosis, tumorigenicity in vivo, and the cytotoxic sensitivity to CIK therapy, in contrast to the control cells. Results: In the current study, we demonstrated that the knockdown of PD-L1 expression in human gastric cancer cells could significantly suppress the cell proliferation, migration, invasion, apoptosis, cell cycle, tumorigenicity in vivo and the cytotoxic sensitivity to CIK therapy. Conclusion: Our results indicate that PD-L1 contributes towards transformation and progression of human gastric cancer cells, and its intervention could prove to be an important therapeutic strategy against gastric cancer.

Background/Aims: The status of interferon (IFN) signaling pathway has been shown to be closely associated with the response of immune checkpoint blockade therapy against advanced human cancers. IFN-induced protein with tetratricopeptide repeats 2 (IFIT2), also known as IFN-stimulated gene 54 (ISG54), is one of the most highly responsive ISGs, which can inhibit the proliferation and migration of cancer cells, and regulate viral replication, resulting in anti-cancer and anti-viral effects. In the present study, we aimed to investigate the role of IFIT2 in human gastric cancer. Methods: Immunohistochemistry assay was used to investigate the correlation between the IFIT2 expression in cancer tissues and clinical parameters of gastric cancer patients. Knockdown of IFIT2 was performed using RNAi to assess the role of IFIT2 in the regulation of biological behaviors in human gastric cancer cell lines. Results: IFIT2 expression in gastric cancer tissues was significantly associated with tumor stage and postoperative prognoses of the patients. Moreover, decreased IFIT2 expression in human gastric cancer cell lines SGC-7901 and AGS significantly increased the cell viability, cell migration and the ratios of cells in S phase. Conclusion: Our present study demonstrated that the decreased IFIT2 expression could promote the gastric cancer progression and predict poor therapeutic outcomes of the patients.

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