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BackgroundImmunotherapy and its mechanisms are being studied in a wide variety of cancers. Programmed cell death ligand 1 (PDL1) is associated with immune evasion in numerous tumor types. Here, we aimed to assess the relationship between metastasis associated in colon cancer‐1 (MACC1) and PDL1 and examine their effects on gastric cancer (GC) tumor immunity.MethodsThe expression of MACC1, c‐Met, and PDL1 in human GC tissues was first assessed using quantitative RT‐PCR (qRT‐PCR) and immunohistochemistry. We then focused on the relationships among MACC1, c‐Met, and PDL1 using RT‐PCR and western blotting after cell transfection and inhibitor treatment in vitro and on the identification of their roles in immune killing in vitro and in vivo.ResultsWe found that expression of MACC1, c‐Met, and PDL1 was upregulated in human GC tissues, and there was a positive correlation between the expression levels. In addition, we found that ectopic expression of MACC1 (silencing and overexpression by transfection) resulted in corresponding changes in c‐Met and PDL1 expression levels, and c‐Met/AKT/mTOR pathway inhibitors (SU11274, MK2206, and rapamycin) blocked the regulation of PDL1 expression by MACC1. Furthermore, silencing of MACC1 led to an increase in antitumor and immune killing in vitro and in vivo, and overexpression of MACC1 resulted in a decrease in tumor immunity in vitro and in vivo.ConclusionsFrom these data, we infer that MACC1 regulates PDL1 expression and tumor immunity through the c‐Met/AKT/mTOR pathway in GC cells and suggest that MACC1 may be a therapeutic target for GC immunotherapy.

HOXC10 plays a critical role in many cellular processes, such as proliferation, migration, and invasion, but the function of HOXC10 in gastric carcinoma is not clear.In this study, we aimed to investigate the expression profile of HOXC10 and its role in gastric carcinoma cells and in vivo experiments. HOXC10 expression patterns were detected in clinical samples and gastric cancer cells lines by reverse transcriptase polymerase chain reaction assays, and then, we focused on its role in regulating cell proliferation, cell cycle, migration, and invasion after transfection of silencing and overexpression plasmids in vitro and in vivo. Finally, we confirmed the correlation between HOXC10 and nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), and epidermal growth factor receptor expression. We found that HOXC10 expression increased in clinical samples, especially in poorly differentiated (PD) gastric cancer cells. Silencing HOXC10 suppressed proliferation, migration, and invasion in vitro, and inhibited tumor growth and induced apoptosis in vivo. Overexpression of HOXC10 showed the opposite effect on PD gastric cancer cells. In addition, silencing HOXC10 inhibited the expression of interleukin-6, TNF-α, TGF-β, and epidermal growth factor, and overexpressing HOXC10 induced their expression both in vitro and in vivo. Luciferase reporter assays and chromatin immunoprecipitation indicated that HOXC10 may activate the NF-κB signaling pathway through regulation of P65 transcriptional activity by binding to the P65 promoter. HOXC10 may play an important role in PD gastric carcinoma cell proliferation, cell cycle, migration, invasion, and metastasis through upregulating proinflammatory cytokines via NF-κB pathway, suggesting HOXC10 may serve as a novel therapeutic target for PD gastric cancer.

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9602 Background: Alflutinib (AST2818) is a third generation EGFR-TKI. This phase IIb, multicenter, single arm study (ALSC003, NCT03452592) aimed to assess the efficacyand safety of Alflutinib in patients with EGFR T790M mutated non-small cell lung cancer (NSCLC). Methods: Patients with locally advanced or metastatic EGFR T790M mutated NSCLC who progressed after first/second-generation EGFR-TKIs therapy or primary EGFR T790M mutation positive received 80 mg Alflutinib orally once daily. Tumor tissue samples underwent central laboratory testing for EGFR T790M mutation. The primary endpoint was objective response rate (ORR). Secondary endpoints included disease control rate (DCR), duration of response (DoR), progression-free survival (PFS), overall survival (OS) and safety. Efficacy was assessed by independent radiological review committee per RECIST 1.1. Safety was assessed by NCI CTCAE version 4.03. Results: From Jun 4, 2018 to Dec 8, 2018, 220 patients were enrolled with a median age of 61.0 (range 29 to 80) years. According to the AJCC version 8 staging system, 212 (96.4%) cases were in stage IV, and 8 (3.6%) cases in stage III. All patients had EGFR T790M mutation. By April 12, 2019, the ORR was 73.6% (95% CI 67.3–79.3). The DCR estimated at 6 and 12 weeks were 87.3% (95%CI 82.1-91.4) and 82.3% (95%CI 76.6-87.1), respectively. The median PFS was 7.6 months (95% CI 7.0–NA). Median OS and DoR have not been reached. 209 (95.0%) patients had at least one adverse events (AEs), which were mostly grade 1 or 2 and well tolerable. The most common AEs were increased aspartate aminotransferase (33 [15.0%]), upper respiratory tract infection (33 [15.0%]), and cough (33 [15.0%]). Grade 3 to 5 AEs occurred in 42 (19.1%) patients. The most common one was elevated γ-glutamyltransferase (n = 4). There were 3 deaths patients, 2 of which possibly not be related to the study drug, and 1 could not be determined. No interstitial pneumonia was reported. Conclusions: Alflutinib has promising efficacy and acceptable safety profile for the treatment of EGFR T790M mutated NSCLC patients. Clinical trial information: NCT 03452592 .