PD-1/PD-L1信号途径在肿瘤免疫逃逸机制中的作用

PD-1／PD—L1作为免疫球蛋白超家族协同刺激分子的重要成员，参与自身免疫、移植免疫以及肿瘤免疫等机体免疫调节过程。PD-1是-个主要表达在活化T细胞上的抑制性受体，与其配体PD—L1结合，可显著抑制T细胞的活化和增殖，并调节细胞因子的表达和分泌。PD—L1则广泛表达在多种免疫细胞、上皮细胞以及肿瘤细胞上。目前诸多研究表明，多种人类肿瘤大量表达的PD．L1分子与患者临床病理特征及预后紧密相关，成为肿瘤检出和预后判断的新的生物学指标。肿瘤细胞通过高表达PD—L1分子，与T细胞上的受体PD-1的结合，传递负性调控信号，导致肿瘤抗原特异性T细胞的诱导凋亡和免疫无能，使肿瘤细胞逃避机体的免疫监控和杀伤。阐明PD-1／PD—L1信号转导机制在肿瘤免疫应答中的作用，并尝试将阻断该信号通路应用于肿瘤免疫治疗，对进-步拓展肿瘤治疗的思路和方法具有重要价值。     

PD-L1-Ig融合蛋白的酵母表达及其对T细胞的抑制作用

目的：利用毕赤酵母表达系统表达PDL1Ig融合蛋白,检测该融合蛋白的生物学活性。方法：化学合成hPDL1IgG4融合基因,构建携带该基因的酵母表达载体,转化GS115酵母菌株后分泌表达融合蛋白,亲和层析和离子交换层析法纯化,SDSPAGE和Western blotting分析鉴定。ELISA法检测融合蛋白与受体PD1的结合能力,混合淋巴细胞反应检测融合蛋白对T细胞功能的抑制能力,51Cr稀释法检测其对CTL杀伤人结肠癌SW480细胞效应的抑制作用。结果：成功构建酵母表达载体pPIC9KPDL1IgG4,转化菌株分泌表达PDL1IgG4融合蛋白,相对分子质量为55 000,含量为120 μg/ml。发酵菌株,纯化制备融合蛋白。融合蛋白与受体PD1具有良好的结合能力,能够显著抑制T细胞增殖、活化（P<0.01）,并抑制CTL对结肠癌细胞的杀伤（P<0.01）。结论：成功制备了酵母表达PDL1IgG4融合蛋白,该融合蛋白具有良好的生物学活性,为深入研究其在肿瘤免疫应答中的调控效应奠定了良好基础。     

4-1BB/4-1BBL在树突状细胞上的表达及其生物学意义

41BB/41BB配体（41BBL）属于肿瘤坏死因子受体/肿瘤坏死因子超家属成员,是机体特异性免疫应答中一对重要的共刺激分子，41BB/41BBL相互作用产生的共刺激信号在维持T细胞的增殖、活化及功能介导中发挥了重要作用。最新研究发现,41BB/41BBL共表达于树突状细胞（dendritic cells , DC），通过激发41BB/41BBL为DC活化提供了新的思路，进而增强DC激发T细胞的能力。因此，调节41BB/41BBL信号在以DC为主介导的肿瘤免疫中具有广阔的应用前景。     

PD1/PD-L1激活促进癌症发生、发展和转移的研究进展北大核心CSCD

程序性死亡受体1(PD1)和程序性死亡配体1(PD-L1)是重要的负性免疫调节因子。T细胞表面PD1受体与肿瘤细胞表面表达的PD-L1配体结合,向细胞内传递调控信号,抑制T细胞活化与增殖,从而介导肿瘤细胞的免疫逃逸及对常规放化疗的抵抗。近年来,针对PD1/PD-L1的单克隆抗体靶向药物在非小细胞肺癌和黑色素瘤等实体肿瘤治疗中均取得了较好的疗效,显著改善了部分肿瘤患者的临床进展和不良预后。本文综述了PD1/PD-L1在肿瘤发生、发展和转移中的重要作用以及PD1/PD-L1抗体应用于肿瘤免疫治疗中的最新进展。     

人PD-L1(B7-H1)基因克隆及其逆转录病毒载体的构建和稳定表达

目的：克隆人PDL1(B7H1)基因，并构建含有该目的基因的重组逆转录病毒载体，获得稳定表达PDL1基因的L929细胞。方法：从人心脏cDNA文库中扩增出PDL1基因，通过双酶切装入逆转录病毒载体pGEZTerm中，脂质体法共转染包装细胞293T，用含有完整病毒颗粒的293T细胞的培养上清感染L929细胞，72 h后，加入Zeocin进行筛选，挑选出能稳定表达PDL1蛋白的L929细胞株。结果：构建了用于表达的含PDL1基因的重组逆转录病毒载体；经转染包装细胞293T后，包装出具有感染能力的重组PDL1逆转录病毒；经RTPCR、流式细胞仪表型检测表明，筛选出的L929转基因细胞能稳定表达人PDL1蛋白。结论：构建了含人PDL1基因重组逆转录病毒载体和稳定表达人PDL1蛋白的细胞株，为该基因功能的后续研究和单克隆抗体的研制奠定了基础。     

PD 1／PD L1通路及其抗体耐药机制的研究进展#br#

程序性死亡受体1（PD 1）／程序性死亡受体配体1（PD L1）能通过调节细胞信号通路和表观遗传修饰来抑制T细胞、B细胞的增殖和效应作用。近几年来,在多种恶性肿瘤中,PD 1／PD L1通路的免疫检查点抑制剂取得了令人惊喜的临床治疗效果,但随之而来的原发性和继发性耐药成为了新的问题,不仅影响了PD 1／PD L1抗体的治疗效果,也限制了其在临床的广泛应用。本文就PD 1/PD L1相关信号通路以及导致PD 1/PD L1抗体耐药的相关机制作一综述。     

以PD-1和PD-L1为靶点的肿瘤免疫治疗研究进展

近年来,肿瘤免疫治疗取得了显著的进展,对肿瘤患者有良好的疗效,成为继手术、放疗和化疗后治疗恶性肿瘤的新模式。目前,程序性死亡受体1(PD-1)/程序性死亡受体配体1(PD-L1)为靶点的免疫治疗是当前肿瘤免疫治疗的研究热点。PD-1是一种抑制T细胞炎性活动的细胞表面受体,属于B7-CD28受体家族成员,常在患者的T细胞中表达;PD-L1是B7家族中的共刺激信号分子,在多种肿瘤细胞和肿瘤组织中均有表达,PD-1/PD-L1通路在诱导效应T细胞凋亡、抑制T细胞活化、抑制机体抗肿瘤免疫反应和肿瘤免疫逃逸过程中发挥重要作用。目前以PD-1和PD-L1为靶点的肿瘤免疫治疗主要分为如下五类:小分子抑制剂、单克隆抗体、双特异性抗体、抗体药物偶联物以及细胞免疫治疗。本研究针对这五类治疗的最新进展进行综述。     

PD －1／PD －L1通路在肿瘤免疫逃逸中的研究进展

程序性死亡因子1及其配体 PD －L1／PD －L2是一组负性共抑制分子,在肿瘤细胞逃避宿主免疫反应方面起重要作用。肿瘤患者 PD －L1的表达与肿瘤浸润深度、淋巴结转移、病理类型、总生存时间呈正相关性。对 PD －1／PD －L1通路的研究可以更深入了解肿瘤细胞在免疫监控环境下如何发生发展,同时为肿瘤的治疗提供新靶点和新思路。     

肿瘤细胞固有程序性死亡受体1及其生物学功能研究进展

在肿瘤微环境中,程序性死亡受体1(PD-1)是免疫抑制因子之一,通过与其配体程序性死亡受体配体1(PD-L1)和(或)PD-L2结合后调节淋巴细胞的活化、无能或衰竭等生物学过程.既往的研究中,PD-1只在免疫细胞尤其是功能耗竭的T细胞中表达,通过作用于磷脂酰肌醇-3-羟激酶(PI3K)、蛋白激酶B(AKT)、大鼠肉瘤癌基因(RAS)、促分裂原活化的蛋白激酶(MAPK)/细胞外信号调节激酶(ERK)1/2等相关下游通路导致肿瘤细胞发生免疫逃逸.PD-1在黑色素瘤、肝细胞癌、胰腺癌、结肠癌及非小细胞肺癌等多种肿瘤细胞中固有表达并激活多种信号通路,发挥不同的生物学效应.这些生物学效应均独立于机体的适应性免疫,对肿瘤细胞的增殖发挥促进或抑制作用.目前肿瘤细胞固有PD-1的表达及作用机制尚不明确,但这提示PD-1在肿瘤细胞中的产生和作用机制可能不同于经典的PD-1/PD-L1免疫检查点信号通路,可协助理解PD-1/PD-L1免疫检查点抑制剂在不同肿瘤治疗中疗效不同的可能原因,为补充和完善现有的免疫检查点治疗方案提供重要线索.     

PD-1/PD-L1通路在乳腺癌治疗中的作用及意义

程序性死亡受体1（programmed death-1,PD-1,CD279）为共刺激受体CD28超家族成员,主要表达在活化T细胞、B细胞、单核细胞以及自然杀伤细胞表面。程序性死亡配体1（programmed death-ligand 1,PD-L1,CD274）为PD-1的一个重要配体,广泛表达于肿瘤细胞以及抗原呈递细胞（APC）表面。以PD-1/PD-L1为靶点的肿瘤免疫治疗为肿瘤治疗开辟了新的道路。PD-1通过与PD-L1和(或)PD-L2结合,抑制T细胞活化,诱导T细胞凋亡,在肿瘤免疫逃逸中起着重要的作用。目前PD-1/PD-L1信号通路成为免疫靶向治疗的新靶点,相关研究在非小细胞肺癌、晚期黑色素瘤等多种恶性肿瘤领域有重大进展,研究发现PD-L1 在多种肿瘤细胞包括乳腺癌中表达上调,提示 PD-1/PD-L1通路可能参与肿瘤的免疫逃逸。本文将针对PD-1/PD-L1通路在乳腺癌治疗中的作用及意义进行综述。     

Resistance to PD1/PDL1 checkpoint inhibition

For the first time in decades, patients with difficult-to-treat cancers such as advanced stage metastatic melanoma are being offered a glimpse of hope in the form of immunotherapies. By targeting factors that foster the development and maintenance of an immunosuppressive microenvironment within tumors, these therapies release the brakes on the host’s own immune system; allowing cure of disease. Indeed, phase III clinical trials have revealed that therapies such as ipilimumab and pembrolizumab which target the CTLA4 and PD-1 immune checkpoints, respectively, have raised the three-year survival of patients with melanoma to ∼70%, and overall survival (>5 years) to ∼30%. Despite this unprecedented efficacy, many patients fail to respond, and more concerning, some patients who demonstrate encouraging initial responses to immunotherapy, can acquire resistance over time. There is now an urgent need to identify mechanisms of resistance, to predict outcome and to identify targets for combination therapy. Here, with the aim of guiding future combination trials that target specific resistance mechanisms to immunotherapies, we have summarised and discussed the current understanding of mechanisms promoting resistance to anti-PD1/PDL1 therapies, and how combination strategies which target these pathways might yield better outcomes for patients.     

PD1/PD-L1抑制剂治疗肿瘤

近年来,程序死亡分子(programmed death-1,PDl)/PD1配体(PD1 ligand,PD-L1)抑制剂在黑色素瘤的治疗中取得了突破性进展,并迅速应用到其他类型肿瘤,其中包括肺癌、乳腺癌、肝癌、胰腺癌、消化道肿瘤、妇科肿瘤、泌尿系统肿瘤以及骨髓瘤和淋巴瘤等多种恶性肿瘤,许多临床试验证明了抗PD1/PD-L1治疗可显著改善癌症患者生存期,并且治疗相关不良反应耐受性尚可.目前关于其抗肿瘤活性及安全性的研究仍在继续,并进一步探索其诊断、疗效评估的理想生物标记物,以及用于长期监测的方法,期待这些问题的解决,使抗PD1/PD-L1治疗更加系统、完善,为更多的癌症患者带来生存获益.     

PD-1信号通路在非小细胞肺癌中的研究进展

免疫治疗是目前除手术、化疗、放疗及靶向治疗外,另一种能够有效改善肺癌预后的治疗方法。在各种免疫治疗方法中,免疫检查点抑制剂(immune checkpoint inhibitors,ICI)在近年来发展迅速,已成为肿瘤治疗领域的新兴疗法及研究热点。其中,程序性死亡受体1(programmed death receptor 1,PD 1)及其配体程序性死亡配体 1(programmed death receptor ligand1,PD L1)的抑制剂在多种恶性肿瘤的治疗中均取得了显著疗效,部分药物已被美国FDA批准应用于临床。该文对PD 1／PD L1抑制剂在晚期非小细胞肺癌(non small cell lung cancer,NSCLC)患者治疗中的临床研究现状进行综述,探讨其在晚期NSCLC治疗中的临床应用价值、前景及面临的问题与挑战。     

PD1 and PDL1 expression in primary central nervous system diffuse large B‐cell lymphoma are frequent and expression of PD1 predicts poor survival

Primary central nervous system diffuse large B‐cell lymphoma (PCNS‐DLBCL) is a rare and aggressive type of diffuse large B‐cell lymphoma (DLBCL) whit poorly understood pathogenesis. Finding biomarkers associated with patient survival may be important for understanding its physiopathology and to develop new therapeutic approaches. We investigated 32 PCNS‐DLBCL from immunocompetent patients for BCL2, CMYC, LMO2, and P53 expression and for cytogenetic aberrations of BCL2, BCL6, and MYC genes, all known for their prognostic value in systemic DLBCL (s‐DLBCL). We analyzed PD1 and PDL1 protein expression in both tumor infiltrating lymphocytes (TILs) and tumor cells. Finally, we searched for correlation between biological data and clinical course. The PCNS‐DLBCL expressed BCL2, CMYC, LMO2, and P53 at similar frequency than s‐DLBCL but without significant prognostic on survival. None cases harbored aberrations involving BCL2 and MYC gene whereas BCL6 abnormalities were present in 20.7% of cases but without value on survival. Expression of PD1 in TILs and PDL1 in tumor cells was observed at higher rates than in s‐DLBCL (58% and 37%, respectively). The PD1 expression in TILs correlated with PDL1 expression in tumor cells (P = .001). Presence of PD1 positive TILs was associated with poorer overall survival (P = .011). Patients with PDL1 overexpression tended to better response to chemotherapy (P = .23). In conclusion PCNS‐DLBCL pathogenesis differs from s‐DLBCL without prognostic value of the phenotypic and cytogenetic parameters known for their pejorative impact in the latter. The PD1/PDL1 pathway plays a strong role in PCNS‐DLBCL and represents an attractive target for this aggressive lymphoma.     

Frequent expression of PD‐L1 on circulating breast cancer cells

Immune checkpoint regulators such as PD‐L1 have become exciting new therapeutic targets leading to long lasting remissions in patients with advanced malignancies. However, in view of the remarkable costs and the toxicity profiles of these therapies, predictive biomarkers able to discriminate responders from non‐responders are urgently needed. In the present paper, we provide evidence that PD‐L1 is frequently expressed on metastatic cells circulating in the blood of hormone receptor‐positive, HER2‐negative breast cancer patients. We performed western blot, flow cytometry and immunocytochemical analyses to demonstrate the specificity of the PDL1 antibody used in our study and established immunoscores for PDL1 expression on single tumor cells. We then selected sixteen patients with circulating tumor cells (CTCs) using the CellSearch® system and found PD‐L1(+) CTCs in 11 patients (68.8%). The fraction of PD‐L1(+) CTCs varied from 0.2 to 100% in individual patients. This is the first report demonstrating the expression of PD‐L1 on CTCs. The established CTC/PD‐L1 assay can be used for liquid biopsy in future clinical trials for stratification and monitoring of cancer patients undergoing immune checkpoint blockade.     

Association between PD1 mRNA and response to anti-PD1 monotherapy across multiple cancer types

BackgroundWe hypothesized that the abundance of PD1 mRNA in tumor samples might explain the differences in overall response rates (ORR) observed following anti-PD1 monotherapy across cancer types.Patients and methodsRNASeqv2 data from 10 078 tumor samples representing 34 different cancer types was analyzed from TCGA. Eighteen immune-related gene signatures and 547 immune-related genes, including PD1, were explored. Correlations between each gene/signature and ORRs reported in the literature following anti-PD1 monotherapy were calculated. To translate the in silico findings to the clinical setting, we analyzed the expression of PD1 mRNA using the nCounter platform in 773 formalin-fixed paraffin embedded (FFPE) tumor samples across 17 cancer types. To test the direct relationship between PD1 mRNA, PDL1 immunohistochemistry (IHC), stromal tumor-infiltrating lymphocytes (sTILs) and ORR, we evaluated an independent FFPE-based dataset of 117 patients with advanced disease treated with anti-PD1 monotherapy.ResultsIn pan-cancer TCGA, PD1 mRNA expression was found strongly correlated (r > 0.80) with CD8 T-cell genes and signatures and the proportion of PD1 mRNA-high tumors (80th percentile) within a given cancer type was variable (0%–84%). Strikingly, the PD1-high proportions across cancer types were found strongly correlated (r = 0.91) with the ORR following anti-PD1 monotherapy reported in the literature. Lower correlations were found with other immune-related genes/signatures, including PDL1. Using the same population-based cutoff (80^th percentile), similar proportions of PD1-high disease in a given cancer type were identified in our in-house 773 tumor dataset as compared with TCGA. Finally, the pre-established PD1 mRNA FFPE-based cutoff was found significantly associated with anti-PD1 response in 117 patients with advanced disease (PD1-high 51.5%, PD1-intermediate 26.6% and PD1-low 15.0%; odds ratio between PD1-high and PD1-intermediate/low = 8.31; P < 0.001). In this same dataset, PDL1 tumor expression by IHC or percentage of sTILs was not found associated with response.ConclusionsOur study provides a clinically applicable assay that links PD1 mRNA abundance, activated CD8 T-cells and anti-PD1 efficacy.