Therapy Resistance in Neoadjuvantly Treated Gastric Cancer and Cancer of the Gastroesophageal Junction is Associated with an Increased Expression of Immune Checkpoint Inhibitors-Comparison Against a Therapy Naïve Cohort.
- 作者列表："Schoop H","Bregenzer A","Halske C","Behrens HM","Krüger S","Egberts JH","Röcken C
:With recent studies uncovering the complex landscape of immune checkpoint regulators in gastric cancer (GC), we aimed to characterize the expression of the checkpoint proteins V-domain Ig suppressor of T-cell activation (VISTA), programmed cell death 1 ligand 1 (PD-L1), and programmed cell death protein-1 (PD-1) in a cohort of GCs following platinum-based neoadjuvant chemotherapy. A total of 141 GC samples, 93 lymph node metastases, and 15 distant metastases were assessed using immunohistochemistry. Staining results were correlated with clinicopathological patient characteristics, genetic alterations, and survival. The expression of VISTA was detected in tumor cells of 38 (30.9%) GCs and immune cells of 139 (98.6%) GCs. The expression of PD-L1 was detected in tumor cells of 27 (22.7%) GCs and immune cells of 134 (96.4%) GCs. The expression of PD-1 was only observed in lymphocyte aggregates/intratumoral lymphoid follicles of 123 (87.2%) GCs. VISTA and PD-L1 correlated in their expression and were associated with poor tumor regression. Compared with an ancient cohort of therapy naïve GCs, we observed a major increase in overall immune cell density accompanied by an over proportional increase in PD-1 and VISTA-positive immune cells. The frequency of VISTA expression in tumor cells was also found to be substantially increased. To the contrary, expression of PD-L1 was decreased in immune cells and tumor cells of neoadjuvantly treated GCs. As a result, a subset of GCs using a single (only VISTA or PD-L1) or combined (VISTA and PD-L1) immune evasion mechanisms might benefit from an anti-PD-L1/anti-VISTA-targeted therapy.
: 最近的研究揭示了胃癌 (GC) 中免疫检查点调节剂的复杂景观, 我们旨在表征 T 细胞活化的检查点蛋白 V 结构域 Ig 抑制因子 (VISTA) 、程序性细胞死亡 1 配体 1 (PD-L1) 的表达, 和程序性细胞死亡蛋白-1 (PD-1)在以铂类为基础的新辅助化疗后 GCs 的队列研究中。使用免疫组织化学共评估了 141 例 GC 样本、 93 例淋巴结转移和 15 例远处转移。染色结果与临床病理患者特征、遗传改变和生存相关。在 38 例 (30.9%) GCs 的肿瘤细胞和 139 例 (98.6%) GCs 的免疫细胞中检测到 VISTA 的表达。在 27 例 (22.7%) GCs 的肿瘤细胞和 134 例 (96.4%) GCs 的免疫细胞中检测到 PD-L1 的表达。仅在 123 (87.2%) GCs 的淋巴细胞聚集体/瘤内淋巴滤泡中观察到 PD-1 的表达。VISTA 和 PD-L1 的表达相关，并与肿瘤消退不良相关。与一个古老的治疗初治 GCs 队列相比，我们观察到整体免疫细胞密度显著增加，伴随着 PD-1 和 VISTA 阳性免疫细胞的比例增加。还发现肿瘤细胞中 VISTA 表达的频率大幅增加。新佐剂治疗后，PD-L1 在免疫细胞和肿瘤细胞中表达降低。因此，使用单一 (仅 VISTA 或 PD-L1) 或联合 (VISTA 和 PD-L1) 免疫逃避机制的 GCs 子集可能受益于 anti-PD-L1/抗 VISTA 靶向治疗。
METHODS::Macrophages (MΦ) play a critical role in tumor growth, immunosuppression and inhibition of adaptive immune responses in cancer. Hence, targeting signaling pathways in MΦs that promote tumor immunosuppression will provide therapeutic benefit. PI3Kγ has been recently established by our group and others as a novel immuno-oncology target. Herein, we report that a macrophage Syk-PI3K axis drives polarization of immunosuppressive MΦs which establish an immunosuppressive tumor microenvironment in in vivo syngeneic tumor models. Genetic or pharmacological inhibition of Syk and/or PI3Kγ in MΦs promotes a pro-inflammatory MΦphenotype, restores CD8+ T cell activity, destabilizes HIF under hypoxia, and stimulates an antitumor immune response. Assay for Transposase-accessible Chromatin using Sequencing (ATAC-seq) analyses on the bone marrow derived macrophages (BMDMs) show that inhibition of Syk kinase promotes activation and binding of NF-κB motif in SykMC-KO BMDMs, thus stimulating immunostimulatory transcriptional programming in MΦs to suppress tumor growth. Finally, we have developed in silico the "first in class" dual Syk/PI3K inhibitor, SRX3207, for the combinatorial inhibition of Syk and PI3K in one small molecule. This chemotype demonstrates efficacy in multiple tumor models and represents a novel combinatorial approach to activate antitumor immunity.
METHODS::Dysfunction of invariant natural killer T (iNKT) cells in tumor microenvironment hinders their anti-tumor efficacy, and the underlying mechanisms remain unclear. Here we report that iNKT cells increase lipid biosynthesis after activation, and that is promoted by PPARγ and PLZF synergically through enhancing transcription of Srebf1. Among those lipids, cholesterol is required for the optimal IFN-γ production from iNKT cells. Lactic acid in tumor microenvironment reduces expression of PPARγ in intratumoral iNKT cells and consequently diminishes their cholesterol synthesis and IFN-γ production. Importantly, PPARγ agonist pioglitazone, a thiazolidinedione drug for type 2 diabetes, successfully restores IFN-γ production in tumor-infiltrating iNKT cells from both human patients and mouse models. Combination of pioglitazone and alpha-galactosylceramide treatments significantly enhances iNKT cell-mediated anti-tumor immune responses and prolongs survival of tumor-bearing mice. Our studies provide a strategy to augment the anti-tumor efficacy of iNKT cell-based immunotherapies via promoting their lipid biosynthesis.
METHODS::Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed and selective cancer treatment that induces necrotic and immunogenic cell death and utilizes a monoclonal antibody conjugated to a photo-absorber dye, IR700DX, activated by NIR light. Although CD44 is surface cancer marker associated with drug resistance, anti-CD44-IR700 NIR-PIT results in inhibited cell growth and prolonged survival in multiple tumor types. Meanwhile, anti-CD25-IR700-targeted NIR-PIT has been reported to achieve selective and local depletion of FOXP3+CD25+CD4+ regulatory T cells (Tregs), which are primary immunosuppressive cells in the tumor microenvironment (TME), resulting in activation of local antitumor immunity. Combined NIR-PIT with CD44- and CD25-targeted agents has the potential to directly eliminate tumor cells and also amplify the immune response by removing FOXP3+CD25+CD4+ Tregs from the TME. We investigated the difference in therapeutic effects of CD44-targeted NIR-PIT alone, CD25-targeted NIR-PIT alone, and the combination of CD44- and CD25-targeted NIR-PIT in several syngeneic tumor models, including MC38-luc, LL/2, and MOC1. The combined NIR-PIT showed significant tumor growth inhibition and prolonged survival compared with CD44-targeted NIR-PIT alone in all tumor models and showed prolonged survival compared with CD25-targeted NIR-PIT alone in MC38-luc and LL/2 tumors. Combined CD44/CD25 NIR-PIT also resulted in some complete remissions, whereas this was not achieved with either type of NIR-PIT alone. Therefore, combined NIR-PIT simultaneously targeting cancer antigens and immunosuppressive cells in the TME may be more effective than either type of NIR-PIT alone and may have potential to induce prolonged immune responses in treated tumors.