Project description:Introduction
Immune checkpoint blockade (ICB) immunotherapy has revolutionized cancer treatment, demonstrating exceptional clinical responses in a wide range of cancers. Despite the success, a significant proportion of patients still fail to respond, highlighting the existence of unappreciated mechanisms of immunotherapy resistance. Delineating such mechanisms is paramount to minimize immunotherapy failures and optimize the clinical benefit.
Methods
In this study, we treated tumour-bearing mice with PD-L1 blockage antibody (aPD-L1) immunotherapy, to investigate its effects on cancer-induced emergency myelopoiesis, focusing on bone marrow HSPCs. We examined the impact of aPD-L1 treatment on HSPC quiescence, proliferation, transcriptomic profile, and functionality.
Results
Herein, we reveal that aPD-L1 in tumour-bearing mice targets the hematopoietic stem and progenitor cells (HSPCs) in the bone marrow (ΒΜ), mediating their exit from quiescence and promoting their proliferation. Notably, disruption of the PDL1/PD1 axis induces transcriptomic reprogramming in HSPCs, observed in both individuals with Hodgkin lymphoma (HL) and tumour-bearing mice, shifting towards an inflammatory state. Furthermore, HSPCs from aPDL1-treated mice demonstrated resistance to cancer-induced emergency myelopoiesis, evidenced by a lower generation of MDSCs compared to control-treated mice.
Discussion:
Our findings shed light on unrecognized mechanisms of action of ICB immunotherapy in cancer, which involves targeting of BM-driven HSPCs and reprogramming of cancer-induced emergency myelopoiesis.
Project description:Although genomic instability can trigger cancer-intrinsic innate immune responses that promote tumor rejection, cancer cells often evade these responses by overexpressing immune checkpoint regulators, such as PD-L1. Here, we identify the SNF2-family DNA translocase SMARCAL1 as a factor that favors tumor immune evasion by a dual mechanism involving both the suppression of innate immune signaling and the induction of PD-L1-mediated immune checkpoint responses. Mechanistically, SMARCAL1 relieves endogenous DNA damage and suppresses cGAS-STING-dependent immune signaling during cancer cell growth. Simultaneously, it cooperates with the AP-1 family member JUN to maintain chromatin accessibility at a transcriptional regulatory element in the PD-L1 gene, thereby promoting PD-L1 expression in cancer cells. Loss of SMARCAL1 enhances anti-tumor immune responses and sensitizes tumors to immune checkpoint blockade in a mouse melanoma model. Collectively, these studies uncover SMARCAL1 as a valuable target for cancer immunotherapy.
Project description:Blocking PD-1 can reinvigorate exhausted CD8 T cells (TEX) and improve control of chronic infections and cancer. One potential advantage of this immunotherapy is durable protection if immune memory can be established. It is unclear, however, whether blocking PD-1 can reprogram TEX into effector (TEFF) or durable memory T cells (TMEM). Here, we found reinvigoration of TEX by PD-L1 blockade caused re-acquisition of some features of TEFF, but minimal memory development. We used microarray analysis to profile exhausted cells from anti-PD-L1 mice after two weeks of treatment to study if PD-L1 blockade caused re-acquistion of some feature of effector or memory cells.
Project description:Genomic instability can trigger cancer-intrinsic innate immune responses that promote tumor rejection. However, cancer cells often evade these responses by overexpressing immune checkpoint regulators, such as PD-L1. Here, we identify the SNF2-family DNA translocase SMARCAL1 as a factor that favors tumor immune evasion by a dual mechanism involving both the suppression of innate immune signaling and the induction of PD-L1-mediated immune checkpoint responses. Mechanistically, SMARCAL1 relieves endogenous DNA damage and suppresses cGAS-STING-dependent signaling during cancer cell growth. Simultaneously, it cooperates with the AP-1 family member JUN to maintain chromatin accessibility at a transcriptional regulatory element in the PD-L1 gene, thereby promoting PD-L1 expression in cancer cells. SMARCAL1 loss hinders the ability of tumor cells to induce PD-L1 in response to genomic instability, enhances anti-tumor immune responses and sensitizes tumors to immune checkpoint blockade in a mouse melanoma model. Collectively, these studies uncover SMARCAL1 as a promising target for cancer immunotherapy.
Project description:Genomic instability can trigger cancer-intrinsic innate immune responses that promote tumor rejection. However, cancer cells often evade these responses by overexpressing immune checkpoint regulators, such as PD-L1. Here, we identify the SNF2-family DNA translocase SMARCAL1 as a factor that favors tumor immune evasion by a dual mechanism involving both the suppression of innate immune signaling and the induction of PD-L1-mediated immune checkpoint responses. Mechanistically, SMARCAL1 relieves endogenous DNA damage and suppresses cGAS-STING-dependent signaling during cancer cell growth. Simultaneously, it cooperates with the AP-1 family member JUN to maintain chromatin accessibility at a transcriptional regulatory element in the PD-L1 gene, thereby promoting PD-L1 expression in cancer cells. SMARCAL1 loss hinders the ability of tumor cells to induce PD-L1 in response to genomic instability, enhances anti-tumor immune responses and sensitizes tumors to immune checkpoint blockade in a mouse melanoma model. Collectively, these studies uncover SMARCAL1 as a promising target for cancer immunotherapy.
Project description:Exercise training (ExT) has shown antitumor effects in many preclinical cancer models. In the present study, we utilize MC38 and CT26 cells, which represent MSI and MSS colorectal carcinomas respectively, to study the effects and mechanisms of ExT alone or in combination with PD-1 based immunotherapy. Using treadmill running and PD-1/PD-L1 blockade, we demonstrated that post-implant exercise training has broad anticancer activities in murine models of CRC. Specifically, in MSI CRC models, ExT induces beneficial metabolic and immunological adaptations, leading to a more significant inhibition in tumors treated with PD-1/PD-L1 blockade, suggesting a genotype-directed combinatory therapy for the subgroup of CRC patients. Moreover, ExT might be a safe and alternative anticancer strategy for cancers resistant to the PD-1 based immunotherapy, such as patients with MSS CRC tumors.
Project description:Targeting checkpoint blockade to rescue exhausted regulatory T cells (Tregs) has become an essential immunotherapy strategy in treating cancer. Until now, the CD4+ Tregs and PD-1+CD8+ T cells were demonstrated to reduce immunogenic responses. In contrast, little is known about the PD-L1 graphic pattern and characteristics in CD8+ T cells. We performed two high-throughput analysis approaches on tumor-infiltrating CD8+ T cells in lung cancers. We discovered PD-L1+CD8+ T cells enriched in tumor lesions, localized with PD-1+CD8+ affected T cells, and owned regulatory functions. Moreover, tumor-derived IL-27 promoted the development of PD-L1+CD8+ T cells through STAT1/STAT3 signaling. Single-cell RNA sequencing data analysis further clarified the enrichment of PD-L1+CD8+ T cells related to the downregulation of adaptive immune response. Additionally, enrichment of this subset was correlated with poor survival of lung cancer patients. Our data collectively demonstrated that PD-L1+CD8+ T cells potentially become a prognostic biomarker in lung cancer.
Project description:Genomic instability can trigger cancer-intrinsic innate immune responses that promote tumor rejection. However, cancer cells often evade these responses by overexpressing immune checkpoint regulators, such as PD-L1. Here, we identify the SNF2-family DNA translocase SMARCAL1 as a factor that favors tumor immune evasion by a dual mechanism involving both the suppression of innate immune signaling and the induction of PD-L1-mediated immune checkpoint responses. Mechanistically, SMARCAL1 relieves endogenous DNA damage and suppresses cGAS-STING-dependent signaling during cancer cell growth. Simultaneously, it cooperates with the AP-1 family member JUN to maintain chromatin accessibility at a transcriptional regulatory element in the PD-L1 gene, thereby promoting PD-L1 expression in cancer cells. SMARCAL1 loss hinders the ability of tumor cells to induce PD-L1 in response to genomic instability, enhances anti-tumor immune responses and sensitizes tumors to immune checkpoint blockade in a mouse melanoma model. Collectively, these studies uncover SMARCAL1 as a promising target for cancer immunotherapy.
Project description:Lung cancer is a major global health problem, as it is the leading cause of cancer- related deaths worldwide. Non-small-cell lung cancer (NSCLC), the most common form, is a heterogeneous disease with adenocarcinoma and squamous cell carcinoma being the predominant subtypes. Immune-inhibiting interaction of Programmed cell death-ligand 1 (PD-L1) with programmed cell death-protein 1 (PD-1) causes checkpoint mediated immune evasion and is, accordingly, an important therapeutic target in cancer. In NSCLC, improved understanding of PD-1/PD-L1 checkpoint blockade-responsive biology is warranted. We aimed to identify the landscape of immune cell infiltration in primary lung adeno- carcinoma (LUAD) in the context of tumor PD-L1 expression and the extent of immune infiltration (“hot” vs. “cold” phenotype). Therefore, the study comprises LUAD cases (n=138) with “hot” and “cold” tumor immune phenotype and positive and negative tumor PD-L1 expression, respectively. Tumor samples were immunohistochemically analyzed for expression of PD-L1, CD4 and CD8 and further analyzed on transcriptomic level by Nanostring nCouter Pan Cancer Immune Profiling Panel. We detected significantly differentially expressed genes associated with PD-L1 positive and “hot” versus PD-L1 negative and “cold” phenotype. The presented study illustrates novel aspects of PD-L1 regulation, with potential biological relevance, as well as relevance for immunotherapy response stratification.
Project description:Blocking the PD-1/PD-L1 immunosuppressive pathway has shown promise in the treatment of certain cancers including melanoma. This study investigates differences in the gene expression profiles of human melanomas that do or do not display the immunosuppressive protein PD-L1. Further understanding of genes expressed within the tumor microenvironment of PD-L1+ tumors may lead to improved rationally designed treatments. Gene expression profiling was performed on total RNA extracted by laser capture microdissection from 11 archived formalin-fixed paraffin-embedded (FFPE) melanoma specimens, 5 of which were PD-L1 positive and 6 PD-L1 negative. Details of the design, and the gene signatures found are given in the paper associated with this GEO Series: Janis M. Taube, Geoffrey D. Young, Tracee L. McMiller, Shuming Chen, January T. Salas, Theresa S. Pritchard, Haiying Xu, Alan K. Meeker, Jinshui Fan, Chris Cheadle, Alan E. Berger, Drew M. Pardoll, and Suzanne L. Topalian, Differential expression of immune-regulatory genes associated with PD-L1 display in melanoma: implications for PD-1 pathway blockade, Clin Cancer Res 2015, in press.