Effects of Combination of Anti-CTLA-4 and Anti-PD-1 on Gastric Cancer Cells Proliferation, Apoptosis and Metastasis

Abstract

Background/Aims: Gastric cancer (GC) is one of the most common and lethal varieties of cancers. Anticancer activities of anti-CTLA-4 and anti-PD-1 antibodies have been explored in different cancers, including GC. The study aimed to explore the role of combination therapy with anti-CTLA-4 and anti-PD-1 antibodies in GC cells, and understand the possible underlying molecular mechanism. Methods: MKN-45 and MGC-803 cells were divided into four groups, namely control, CTLA-4, PD-1, and CTLA-4&PD-1. Cell viability, cell cycle, apoptosis, migration and invasion were measured by MTT, flow cytometry, and transwell assays, respectively. Expression levels of different mRNAs and proteins associated with apoptosis, epithelial mesenchymal transition (EMT), β-catenin, MAPK, and PI3K/AKT pathways were assessed by RT-qPCR and western blot analysis, respectively. The tumor formation in vivo was examined by tumor Xenograft model assay. Results: Combination with anti-CTLA-4 and anti-PD-1 antibodies significantly suppressed cell proliferation, induced apoptosis, as well as inhibited migration, invasion, and EMT in MKN-45 and MGC-803 cells. Western blotting revealed that combination with anti-CTLA-4 and anti-PD-1 antibodies declined the activation of β-catenin, MAPK and PI3K/AKT signal pathways. Moreover, combination of anti-CTLA-4 and anti-PD-1 antibodies inhibited tumor formation in vivo. Furthermore, the mRNA levels of CTLA-4 and PD-1 were significantly decreased in si-CTLA and si-PD-1 transfected cells, and combination with si-CTLA and si-PD-1 also suppressed cell proliferation, migration, invasion, EMT and induced apoptosis in MKN-45 cells. Conclusion: Combination therapy with anti-CTLA-4 and anti-PD-1 antibodies presented the promising outcomes in GC, although further investigations are warranted.

Evaluation of the roles and regulatory mechanisms of PD-1 target molecules in NSCLC progression

“…PD-1 has been used to treat advanced cancer patients in recent years and had certain therapeutic effects (1)(2)(3). In normal lung and cancer tissues, we found that there was a correlation between the factors of the constructed risk model and the expression level of PD-1.…”

“…Mechanism studies have shown that the anti-CTLA-4 and anti-PD-1 combined therapy could inhibit the activation of β-catenin, MAPK, and PI3K/AKT signaling pathways. Interference with PD-1 expression inhibited GC cell proliferation, migration, invasion, and EMT and induced cell apoptosis (2). Inhibition of BET protein expression inhibited the expression level of PD-1/PD-L1 in triplenegative breast cancer.…”

Biological Landscape of Triple Negative Breast Cancers Expressing CTLA-4

“…It was also reported that over-expression of CTLA-4 promotes the activation of the ERK1/2/MAPK pathway in different tumor types ( 67 , 68 ) and stimulated T-cells ( 69 ). Additionally, coordinated anti-CTLA-4 and anti-PD-1 treatment suppressed the protein levels of phosphorylated ERK1/2 ( 70 ). Our results demonstrate that CD80 treatment induces the phosphorylation of ERK1/2 in HCC1937 cells at short post-treatment times.…”

The Positive and Negative Immunoregulatory Role of B7 Family: Promising Novel Targets in Gastric Cancer Treatment

“…These neutralizing antibodies considerably not only suppressed metastasis and epithelial–mesenchymal transition (EMT) in MGC-803 and MKN-45 cells but also increased the levels of apoptosis. Therefore, combination therapy using CTLA-4 and PD-1-blocking antibodies may improve favorable outcomes in GC patients [ 174 ]. Another study was conducted by Ralph et al regarding inhibition of CTLA-4 using tremelimumab as a monoclonal antibody in esophageal adenocarcinoma and metastatic GC patients.…”