Characterization of the Immune Microenvironment in Hepatocellular Carcinoma.

Purpose: Hepatocellular carcinoma (HCC) often arises in the setting of chronic liver inflammation and may be responsive to novel immunotherapies.Experimental Design: To characterize the immune microenvironment in HCC, IHC staining was performed for CD8-positive T lymphocytes, PD-1-positive, and LAG-3-positive lymphocytes, CD163-positive macrophages, and PD-L1 expression in tumor and liver background from 29 cases of resected HCC.Results: Expression of CD8 was reduced in tumor, and expression of CD163 was reduced at the tumor interface. Positive clusters of PD-L1 expression were identified in 24 of 29 cases (83%), and positive expression of LAG-3 on tumor-infiltrating lymphocytes was identified in 19 of 29 cases (65%). The expression of both PD-L1 and LAG-3 was increased in tumor relative to liver background. No association between viral status or other clinicopathologic features and expression of any of the IHC markers investigated was noted.Conclusions: LAG-3 and PD-L1, two inhibitory molecules implicated in CD8 T-cell tolerance, are increased in most HCC tumors, providing a basis for investigating combinatorial checkpoint blockade with a LAG-3 and PD-L1 inhibitor in HCC. Clin Cancer Res; 23(23); 7333-9. ©2017 AACR.

Yarchoan M ，Xing D ，Luan L ，Xu H ，Sharma RB ，Popovic A ，Pawlik TM ，Kim AK ，Zhu Q ，Jaffee EM ，Taube JM ，Anders RA ... -  《-》

Glycolytic activation of peritumoral monocytes fosters immune privilege via the PFKFB3-PD-L1 axis in human hepatocellular carcinoma.

Programmed cell death 1 ligand 1 (PD-L1) expression on antigen-presenting cells is essential for T cell impairment, and PD-L1-expressing macrophages may mechanistically shape and therapeutically predict the clinical efficacy of PD-L1 or programmed cell death 1 blockade. We aimed to elucidate the mechanisms underlying PD-L1 upregulation in human tumor microenvironments, which remain poorly understood despite the clinical success of immune checkpoint inhibitors. Monocytes/macrophages were purified from peripheral blood, non-tumor, or paired tumor tissues of patients with hepatocellular carcinoma (HCC), and their possible glycolytic switch was evaluated. The underlying regulatory mechanisms and clinical significance of metabolic switching were studied with both ex vivo analyses and in vitro experiments. We found that monocytes significantly enhanced the levels of glycolysis at the peritumoral region of human HCC. The activation of glycolysis induced PD-L1 expression on these cells and subsequently attenuated cytotoxic T lymphocyte responses in tumor tissues. Mechanistically, tumor-derived soluble factors, including hyaluronan fragments, induced the upregulation of a key glycolytic enzyme, PFKFB3, in tumor-associated monocytes. This enzyme not only modulated the cellular metabolic switch but also mediated the increased expression of PD-L1 by activating the nuclear factor kappa B signaling pathway in these cells. Consistently, the levels of PFKFB3+CD68+ cell infiltration in peritumoral tissues were negatively correlated with overall survival and could serve as an independent prognostic factor for survival in patients with HCC. Our results reveal a mechanism by which the cellular metabolic switch regulates the pro-tumor functions of monocytes in a specific human tumor microenvironment. PFKFB3 in both cancer cells and tumor-associated monocytes is a potential therapeutic target in human HCC. Programmed cell death 1 ligand 1 (PD-L1) expressed on antigen-presenting cells, rather than tumor cells, has been reported to play an essential role in checkpoint blockade therapy. A fundamental understanding of mechanisms that regulate the expression of PD-L1 on tumor-infiltrating monocytes/macrophages will undoubtedly lead to the possibility of developing novel PD-L1 blockade strategies with high specificity and efficiency. The current study unveils a novel mechanism by which metabolic switching links immune activation responses to immune tolerance in the tumor milieu, identifying potential targets for future immune-based anti-cancer therapies.

Chen DP ，Ning WR ，Jiang ZZ ，Peng ZP ，Zhu LY ，Zhuang SM ，Kuang DM ，Zheng L ，Wu Y ... -  《-》

Antibodies Against Immune Checkpoint Molecules Restore Functions of Tumor-Infiltrating T Cells in Hepatocellular Carcinomas.

Ligand binding to inhibitory receptors on immune cells, such as programmed cell death 1 (PD-1) and cytotoxic T-lymphocyte associated protein 4 (CTLA4), down-regulates the T-cell-mediated immune response (called immune checkpoints). Antibodies that block these receptors increase antitumor immunity in patients with melanoma, non-small-cell lung cancer, and renal cell cancer. Tumor-infiltrating CD4+ and CD8+ T cells in patients with hepatocellular carcinoma (HCC) have been found to be functionally compromised. We analyzed HCC samples from patients to determine if these inhibitory pathways prevent T-cell responses in HCCs and to find ways to restore their antitumor functions. We collected HCC samples from 59 patients who underwent surgical resection from November 2013 through May 2017, along with tumor-free liver tissues (control tissues) and peripheral blood samples. We isolated tumor-infiltrating lymphocytes (TIL) and intra-hepatic lymphocytes. We used flow cytometry to quantify expression of the inhibitory receptors PD-1, hepatitis A virus cellular receptor 2 (TIM3), lymphocyte activating 3 (LAG3), and CTLA4 on CD8+ and CD4+ T cells from tumor, control tissue, and blood; we studied the effects of antibodies that block these pathways in T-cell activation assays. Expression of PD-1, TIM3, LAG3, and CTLA4 was significantly higher on CD8+ and CD4+ T cells isolated from HCC tissue than control tissue or blood. Dendritic cells, monocytes, and B cells in HCC tumors expressed ligands for these receptors. Expression of PD-1, TIM3, and LAG3 was higher on tumor-associated antigen (TAA)-specific CD8+ TIL, compared with other CD8+ TIL. Compared with TIL that did not express these inhibitory receptors, CD8+ and CD4+ TIL that did express these receptors had higher levels of markers of activation, but similar or decreased levels of granzyme B and effector cytokines. Antibodies against CD274 (PD-ligand1 [PD-L1]), TIM3, or LAG3 increased proliferation of CD8+ and CD4+ TIL and cytokine production in response to stimulation with polyclonal antigens or TAA. Importantly, combining antibody against PD-L1 with antibodies against TIM3, LAG3, or CTLA4 further increased TIL functions. The immune checkpoint inhibitory molecules PD-1, TIM3, and LAG3 are up-regulated on TAA-specific T cells isolated from human HCC tissues, compared with T cells from tumor-free liver tissues or blood. Antibodies against PD-L1, TIM3, or LAG3 restore responses of HCC-derived T cells to tumor antigens, and combinations of the antibodies have additive effects. Strategies to block PD-L1, TIM3, and LAG3 might be developed for treatment of primary liver cancer.

Zhou G ，Sprengers D ，Boor PPC ，Doukas M ，Schutz H ，Mancham S ，Pedroza-Gonzalez A ，Polak WG ，de Jonge J ，Gaspersz M ，Dong H ，Thielemans K ，Pan Q ，IJzermans JNM ，Bruno MJ ，Kwekkeboom J ... -  《-》

The Importance of a Conjoint Analysis of Tumor-Associated Macrophages and Immune Checkpoints in Pancreatic Cancer.

Xu JY ，Wang WS ，Zhou J ，Liu CY ，Shi JL ，Lu PH ，Ding JL ... -  《-》

Impact of Immune Response on Outcomes in Hepatocellular Carcinoma: Association With Vascular Formation.

We investigated the prognostic value of programmed death ligand 1 (PD-L1) expression, tumor-infiltrating CD8-positive T-cell status, and their combination in hepatocellular carcinoma (HCC). Their association with PD-L1 expression and vascular formation was further explored. Using a database of 387 patients who underwent hepatic resection for HCC, immunohistochemical staining of PD-L1, CD8, and CD34 was performed. Additionally, we undertook an enzyme-linked immunosorbent assay for soluble PD-L1. Compared with patients with HCC and PD-L1-negative expression (n = 311), patients with HCC and PD-L1-positive expression (n = 76) showed significantly worse overall survival (OS; multivariate hazard ratio, 2.502; 95% confidence interval [CI], 1.716-3.649; P < 0.0001). The presence of tumor-infiltrating CD8-positive T cells was significantly correlated with longer OS (multivariate hazard ratio, 0.383; 95% CI, 0.274-0.537; P < 0.0001). Stratification based on PD-L1 expression in cancer cells and tumor-infiltrating CD8-positive T-cell status was also significantly associated with OS (log-rank, P < 0.0001). HCC with PD-L1-positive expression was significantly correlated with positivity for vessels that encapsulated tumor clusters. Serum PD-L1 levels were significantly higher in the group of patients who had PD-L1-positive expression than in the group of patients who had PD-L1-negative expression (P = 0.0158). PD-L1 expression in cancer cells was associated with a poor clinical outcome and vascular formation in patients with HCC. Additionally, the combination of PD-L1 expression with tumor-infiltrating CD8-positive T-cell status enabled further classification of patients based on their clinical outcome. Thus, PD-L1 expression in cancer cells and tumor-infiltrating CD8-positive T-cell status might serve as predictive tissue biomarkers.

Itoh S ，Yoshizumi T ，Yugawa K ，Imai D ，Yoshiya S ，Takeishi K ，Toshima T ，Harada N ，Ikegami T ，Soejima Y ，Kohashi K ，Oda Y ，Mori M ... -  《-》