IFN-γ plays a crucial role in anti-tumor responses and also induces expression of PD-L1, a well-established inhibitor of anti-tumor immune function. Understanding how molecular signaling regulates the function of IFN-γ might improve its anti-tumor efficacy. Here, we show that the tumor expression of IFN-γ expression alone has no significant prognostic value in patients with locally advanced lung adenocarcinoma. Surprisingly, patients with tumors expressing both IFN-γ and PD-L1 have the best prognosis compared to those with tumors expressing IFN-γ or PD-L1 alone. Transcriptome analysis demonstrated that tumor tissues expressing IFN-γ display gene expression associated with suppressed cell cycle progression and expansion. Unexpectedly this profile was observed in PD-L1 but not PD-L1- tumors. The current concept is that PD-L1 functions as a shield protecting tumor cells from cytolytic T cell (CTL)-mediated anti-tumor progression. However, our data indicate that PD-L1 expression in the presence of IFN-γ might serve as biomarker for the sensitivity of tumors to the inhibitory effect of IFN-γ. Mechanistic analysis revealed that in lung adenocarcinoma cells IFN-γ-induced activation of JAK2-STAT1 and PI3K-AKT pathways. The activation of JAK2-STAT1 is responsible for the anti-proliferative effect of IFN-γ. Inhibition of PI3K downregulated PD-L1 expression and enhanced the anti-proliferative effect of IFN-γ, suggesting that blockade of PI3K might maximize the IFN-γ-mediated anti-tumor effect. Our findings provide evidence for crosstalk between JAK2-STAT1 and PI3K-AKT pathways in response to IFN-γ in lung adenocarcinoma and have implications for the design of combinatorial targeted therapy and immunotherapy for the treatment of lung adenocarcinoma.

Systemic immune-inflammation index (SII), based on lymphocyte (L), neutrophil (N), and platelet (P) counts, was recently developed and reflects comprehensively the balance of host inflammatory and immune status. We explored its prognostic value in localized gastric cancer (GC) after R0 resection and the potential associations with Thymidine phosphorylase (TYMP), which was reported to increase the migration and invasion of gastric cancer cells. A total of 455 GC patients who received D2 gastrectomy were enrolled. Blood samples were obtained within 1 week before surgery to measure SII (SII = P × N/L). TYMP expression was measured on tumor sections by immunohistochemical analysis. Preoperative high SII indicated worse prognosis (HR: 1.799; 95% CI: 1.174-2.757; p = 0.007) in multivariate analysis and was associated with higher pathological TNM stage, deeper local invasion of tumor and lymph node metastasis (all p < 0.001). SII predicted poor overall survival in pathological TNM stage I subgroup also (p < 0.001). Furthermore we found that in high SII group, positive rate of TYMP expression increased (53.7% vs 42.7%, p = 0.046) and TYMP positive patients had higher SII score (median 405.9 vs. 351.9, p = 0.026). SII, as a noninvasive and low cost prognostic marker, may be helpful to identify higher-risk patients after R0 resection, even for stage I GC patients.

Estrogen receptor (ER) and insulin‐like growth factor‐1 receptor (IGF‐1R) signaling are implicated in lung cancer progression. Based on their previous findings, the authors sought to investigate whether estrogen and IGF‐1 act synergistically to promote lung adenocarcinoma (LADE) development in mice. LADE was induced with urethane in ovariectomized Kunming mice. Tumor‐bearing mice were divided into seven groups: 17β‐estradiol (E2), E2+fulvestrant (Ful; estrogen inhibitor), IGF‐1, IGF‐1+AG1024 (IGF‐1 inhibitor), E2+IGF‐1, E2+IGF‐1+Ful+AG1024 and control groups. After 14 weeks, the mice were sacrificed, and then the tumor growth was determined. The expression of ERα/ERβ, IGF‐1, IGF‐1R and Ki67 was examined using tissue‐microarray‐immunohistochemistry, and IGF‐1, p‐ERβ, p‐IGF‐1R, p‐MAPK and p‐AKT levels were determined based on Western blot analysis. Fluorescence‐quantitative polymerase chain reaction was used to detect the mRNA expression of ERβ, ERβ2 and IGF‐1R. Tumors were found in 93.88% (46/49) of urethane‐treated mice, and pathologically proven LADE was noted in 75.51% (37/49). In the E2+IGF‐1 group, tumor growth was significantly higher than in the E2 group (p < 0.05), the IGF‐1 group (p < 0.05) and control group (p < 0.05). Similarly, the expression of ERβ, p‐ERβ, ERβ2, IGF‐1, IGF‐1R, p‐IGF‐1R, p‐MAPK, p‐AKT and Ki67 at the protein and/or mRNA levels was markedly higher in the ligand group than in the ligand + inhibitor groups (all p < 0.05). This study demonstrated for the first time that estrogen and IGF‐1 act to synergistically promote the development of LADE in mice, and this may be related to the activation of the MAPK and AKT signaling pathways in which ERβ1, ERβ2 and IGF‐1R play important roles.