Immune Checkpoint Inhibitor Blockade Research Articles

New insights into the role of mast cells as a therapeutic target in cancer through the blockade of immune checkpoint inhibitors.

Mast cells release different anti-and pro-inflammatory agents changing their role from protective to pro-inflammatory cells involved in the progression of different pathological conditions, including autoimmune diseases and tumors. Different mediators released by mast cells are involved in their biological activities which may be anti-tumorigenic and/or pro-tumorigenic. For these reasons, tumor mast cells have been considered a novel therapeutic target to prevent tumor progression and metastatic process. Many different agents have been suggested and used in the past pre-clinical and clinical settings. Among the novel immunotherapeutic approaches to cancer treatment, different immune checkpoint inhibitors targeting PD-1/PDL-1 have been used in the treatment of many human tumors improving overall survival. In this context, inhibition of mast cell activity may be considered a novel strategy to improve the efficacy of anti-PD-1/PDL-1 therapy. The blockade of the PD-1/PD-L1 interaction may be suggested as a useful and novel therapeutic approach in the treatment of tumors in which mast cells are involved.

Primary retroperitoneal choriocarcinoma with lung and liver metastasis in a male patient: case report

Abstract Objectives Non-gestational primary choriocarcinoma is an extremely rare malignant tumor with atypical clinical symptoms, especially in males. It usually occurs in the midline of the body, such as the mediastinum and retroperitoneum. Pathological diagnosis of primary retroperitoneal choriocarcinoma presents many challenges. More importantly, it is insensitive to therapy and has a poor prognosis. To date, there is still no standard treatment strategy for primary choriocarcinoma. Case presentation This case report presented a 27-year-old male with acute abdominal pain as the main symptom. And then, retroperitoneal choriocarcinoma with lung and liver metastasis was diagnosed. Palliative surgery was performed to alleviate the abdominal pain but complete tumor removal was not achieved. Subsequently, we gave the treatment with cytotoxic chemotherapy and immune checkpoint inhibitor blockade. The tumor was significantly reduced in size after six cycles of immunotherapy and chemotherapy, and also β-hCG level returned to normal. The tumor was not in complete remission, so penpulimab immuno-maintenance therapy was given. So far, the tumor control is stable, and the patient’s quality of life is also very well. Conclusions Pathological diagnosis of primary choriocarcinoma is very necessary, and the related molecular markers can assist. Immunotherapy combined with chemotherapy is effective in the treatment of primary retroperitoneal choriocarcinoma.

Elevated Levels of Circulating Hsp70 and an Increased Prevalence of CD94+/CD69+ NK Cells Is Predictive for Advanced Stage Non-Small Cell Lung Cancer.

Non-small cell lung cancer (NSCLC) is the second most frequently diagnosed tumor worldwide. Despite the clinical progress which has been achieved by multimodal therapies, including radiochemotherapy, and immune checkpoint inhibitor blockade, the overall survival of patients with advanced-stage NSCLC remains poor, with less than 16 months. It is well established that many aggressive tumor entities, including NSCLC, overexpress the major stress-inducible heat shock protein 70 (Hsp70) in the cytosol, present it on the plasma membrane in a tumor-specific manner, and release Hsp70 into circulation. Although high Hsp70 levels are associated with tumor aggressiveness and therapy resistance, membrane-bound Hsp70 can serve as a tumor-specific antigen for Hsp70-primed natural killer (NK) cells, expressing the C-type lectin receptor CD94, which is part of the activator receptor complex CD94/NKG2C. Therefore, we investigated circulating Hsp70 levels and changes in the composition of peripheral blood lymphocyte subsets as potential biomarkers for the advanced Union for International Cancer Control (UICC) stages in NSCLC. As expected, circulating Hsp70 levels were significantly higher in NSCLC patients compared to the healthy controls, as well as in patients with advanced UICC stages compared to those in UICC stage I. Smoking status did not influence the circulating Hsp70 levels significantly. Concomitantly, the proportions of CD4+ T helper cells were lower compared to the healthy controls and stage I tumor patients, whereas that of CD8+ cytotoxic T cells was progressively higher. The prevalence of CD3-/CD56+, CD3-/NKp30, CD3-/NKp46+, and CD3-/NKG2D+ NK cells was higher in stage IV/IIIB of the disease than in stage IIIA but were not statistically different from that in healthy individuals. However, the proportion of NK cells expressing CD94 and the activation/exhaustion marker CD69 significantly increased in higher tumor stages compared with stage I and the healthy controls. We speculate that although elevated circulating Hsp70 levels might promote the prevalence of CD94+ NK cells in patients with advanced-stage NSCLC, the cytolytic activity of these NK cells also failed to control tumor growth due to insufficient support by pro-inflammatory cytokines from CD4+ T helper cells. This hypothesis is supported by a comparative multiplex cytokine analysis of the blood in lung cancer patients with a low proportion of CD4+ T cells, a high proportion of NK cells, and high Hsp70 levels versus patients with a high proportion of CD4+ T cells exhibiting lower IL-2, IL-4, IL-6, IFN-γ, granzyme B levels.

Novel antigens for targeted radioimmunotherapy in hepatocellular carcinoma.

Liver cancer is the sixth common cancer and forth cause of cancer-related death worldwide. Based on usually advanced stages of hepatocellular carcinoma (HCC) at the time of diagnosis, therapeutic options are limited and, in many cases, not effective, and typically result in the tumor recurrence with a poor prognosis. Radioimmunotherapy (RIT) offers a selective internal radiation therapy approach using beta or alpha emitting radionuclides conjugated with tumor-specific monoclonal antibodies (mAbs), or specific selective peptides. When compared to chemotherapy or radiotherapy, radiolabeled mAbs against cancer-associated antigens could provide a high therapeutic and exclusive radiation dose for cancerous cells while decreasing the exposure-induced side effects to healthy tissues. The recent advances in cancer immunotherapy, such as blockade of immune-checkpoint inhibitors (ICIs), has changed the landscape of cancer therapy, and the efficacy of different classes of immunotherapy has been tested in many clinical trials. Taking into account the use of ICIs in the liver tumor microenvironment, combined therapies with different approaches may enhance the outcome in the future clinical studies. With the development of novel immunotherapy treatment options in the recent years, there has been a great deal of information about combining the diverse treatment modalities to boost the effectiveness of immunomodulatory drugs. In this opinion review, we will discuss the recent advancements in RIT. The current status of immunotherapy and internal radiotherapy will be updated, and we will propose novel approaches for the combination of both techniques. Potential target antigens for radioimmunotherapy in Hepatocellular carcinoma (HCC). HCC radioimmunotherapy target antigens are the most specific and commonly accessible antigens on the surface of HCC cells. CTLA-4 ligand and receptor, TAMs, PD-1/PD-L, TIM-3, specific IEXs/TEXs, ROBO1, and cluster of differentiation antigens CD105, CD147 could all be used in HCC radioimmunotherapy. Abbreviations: TAMs, tumor-associated macrophages; CTLA-4, cytotoxic T-lymphocyte associated antigen-4; PD-1, Programmed cell death protein 1; PD-L, programmed death-ligand1; TIM-3, T-cell immunoglobulin (Ig) and mucin-domain containing protein-3; IEXs, immune cell-derived exosomes; TEXs, tumor-derived exosomes.

Immune Checkpoint Inhibitors in Human Glioma Microenvironment.

Gliomas are the most common primary brain tumors in adults. Despite the fact that they are relatively rare, they cause significant morbidity and mortality. High-grade gliomas or glioblastomas are rapidly progressing tumors with a very poor prognosis. The presence of an intrinsic immune system in the central nervous system is now more accepted. During the last decade, there has been no major progress in glioma therapy. The lack of effective treatment for gliomas can be explained by the strategies that cancer cells use to escape the immune system. This being said, immunotherapy, which involves blockade of immune checkpoint inhibitors, has improved patients’ survival in different cancer types. This novel cancer therapy appears to be one of the most promising approaches. In the present study, we will start with a review of the general concept of immune response within the brain and glioma microenvironment. Then, we will try to decipher the role of various immune checkpoint inhibitors within the glioma microenvironment. Finally, we will discuss some promising therapeutic pathways, including immune checkpoint blockade and the body’s effective anti-glioma immune response.

Co-stimulatory agonists: An insight into the immunotherapy of cancer.

Immune checkpoint pathways consist of stimulatory pathways, which can function like a strong impulse to promote T helper cells or killer CD8+ cells activation and proliferation. On the other hand, inhibitory pathways keep self-tolerance of the immune response. Increasing immunological activity by stimulating and blocking these signaling pathways are recognized as immune checkpoint therapies. Providing the best responses of CD8+ T cell needs the activation of T cell receptor along with the co-stimulation that is generated via stimulatory checkpoint pathways ligation including Inducible Co-Stimulator (ICOS), CD40, 4-1BB, GITR, and OX40. In cancer, programmed cell death receptor-1 (PD-1), Programmed cell death ligand-1(PD-L1) and Cytotoxic T Lymphocyte-Associated molecule-4 (CTLA-4) are the most known inhibitory checkpoint pathways, which can hinder the immune responses which have specifically anti-tumor characteristics and attenuate T cell activation and also cytokine production. The use of antagonistic monoclonal antibodies (mAbs) that block CTLA-4 or PD-1 activation is used in a variety of malignancies. It has been reported that they can lead to an increase in T cells and thereby strengthen anti-tumor immunity. Agonists of stimulatory checkpoint pathways can induce strong immunologic responses in metastatic patients; however, for achieving long-lasting benefits for the wide range of patients, efficient combinatorial therapies are required. In the present review, we focus on the preclinical and basic research on the molecular and cellular mechanisms by which immune checkpoint inhibitor blockade or other approaches with co-stimulatory agonists work together to improve T-cell antitumor immunity.

Neuroinflammatory changes of the normal brain tissue in cured mice following combined radiation and anti-PD-1 blockade therapy for glioma

The efficacy of combining radiation therapy with immune checkpoint inhibitor blockade to treat brain tumors is currently the subject of multiple investigations and holds significant therapeutic promise. However, the long-term effects of this combination therapy on the normal brain tissue are unknown. Here, we examined mice that were intracranially implanted with murine glioma cell line and became long-term survivors after treatment with a combination of 10 Gy cranial irradiation (RT) and anti-PD-1 checkpoint blockade (aPD-1). Post-mortem analysis of the cerebral hemisphere contralateral to tumor implantation showed complete abolishment of hippocampal neurogenesis, but neural stem cells were well preserved in subventricular zone. In addition, we observed a drastic reduction in the number of mature oligodendrocytes in the subcortical white matter. Importantly, this observation was evident specifically in the combined (RT + aPD-1) treatment group but not in the single treatment arm of either RT alone or aPD-1 alone. Elimination of microglia with a small molecule inhibitor of colony stimulated factor-1 receptor (PLX5622) prevented the loss of mature oligodendrocytes. These results identify for the first time a unique pattern of normal tissue changes in the brain secondary to combination treatment with radiotherapy and immunotherapy. The results also suggest a role for microglia as key mediators of the adverse treatment effect.

Modulatory effects of gut microbiome in cancer immunotherapy: A novel paradigm for blockade of immune checkpoint inhibitors.

The human gastrointestinal (GI) tract harbors gut microbiome, which plays a crucial role in preserving homeostasis at the intestinal host‐microbial interface. Conversely, specific gut microbiota may be altered during various pathological conditions and produce a number of toxic compounds and oncoproteins, in turn, to induce both inflammatory response and carcinogenesis. Recently, promising findings have been documented toward the implementation of certain intestinal microbiome in the next era of cancer biology and cancer immunotherapy. Notably, intestinal microbiota can cooperate with immune checkpoint inhibitors (ICIs) of its host, especially in enhancing the efficacy of programmed death 1 (PD‐1) protein and its ligand programmed death ligand 1 (PD‐L1) blockade therapy for cancer. Herein, we review the dual function of gut microbiota in triggering GI cancers, its association with host immunity and its beneficial functions in modulation of cancer immunotherapy responses. Furthermore, we consider the significance of gut microbiota as a potential biomarker for predicting the efficacy of cancer immunotherapy. Finally, we summarize the relevant limitations that affect the effectiveness and clinical applications of gut microbiome in response to immunotherapy.

A Phase II Study of Double Immune Checkpoint Inhibitor Blockade with Nivolumab and Ipilimumab with or without Azacitidine in Patients with Myelodysplastic Syndrome (MDS)

A Phase II Study of Double Immune Checkpoint Inhibitor Blockade with Nivolumab and Ipilimumab with or without Azacitidine in Patients with Myelodysplastic Syndrome (MDS)

Immune Checkpoint PD-1/PD-L1 CTLA-4/CD80 are Blocked by Rhus verniciflua Stokes and its Active Compounds.

The bark of Rhus verniciflua Stokes (RVS) has been used to treat cancer in Korean herbal medicine. When we screened for PD-1 and CTLA-4 immune checkpoint inhibitors (PD-1/PD-L1 CTLA-4/CD80) from around 800 herbal extracts using competitive Enzyme-Linked Immunosorbent Assay (ELISA), we found that RVS blocked both the PD-1/PD-L1 and the CTLA-4/CD80 interactions. To identify the active compounds from RVS, we performed bioactivity-guided fractionation, and the ethyl acetate (EtOAc) fraction of RVS proved to be the most effective at blocking the PD-1/PD-L1 and CTLA-4/CD80 interactions. In addition, we isolated and identified 20 major compounds in the EtOAc fraction of RVS and then examined the blocking effects of these 20 compounds on PD-1/PD-L1 and CTLA-4/CD80. Among them, four compounds [eriodictyol (7) > fisetin (9) > quercetin (18) > liquiritigenin (13)] blocked the interaction of PD-1/PD-L1 on competitive ELISA. In addition, four different compounds [protocatechuic acid (2) > caffeic acid (19) > taxifolin (5) > butin (6)] blocked the interaction of CTLA-4/CD80. Our findings suggest that RVS and its components could be used as a potential immune checkpoint inhibitor blockade and could be developed for immuno-oncological therapeutics.

1301P - Deep learning radiomics distinguishes intrapulmonary disease from metastases in immunotherapy-treated melanoma patients

BackgroundMelanoma patients have shown sarcoid-like lesions as an immune-related adverse event to anti-PD-1 immunotherapy. Proper discrimination is essential for accurate treatment decision. Aim of the study is to distinguish granulomatous disease (GD) from pulmonary metastases (MET) and enlarged intrapulmonary lymph nodes (LN) in melanoma patients treated with immune checkpoint blockade by using deep learning. MethodsRetrospective (2012-2018) analysis of 165 melanoma patients treated with anti-PD-1 immunotherapy. All patients underwent standardized imaging-based tumor response assessment with contrast enhanced computed tomography (CT) (follow up interval 8-10 weeks) during treatment. Only patients with intrapulmonary lesions were included (n=132, f=72, median age 63 (IQR 55-74ys). All lesions were clustered in 4 different classes: (1) MET, (2) LN, (3) GD, and (4) small (2-5mm) indeterminate calcified granulomas (GC). GD was histologically proven (guided biopsy or operative excision). All LNs and GCs were identified in CT examinations (1-6 years) prior to diagnosis. For all lesions, a labeled region of interest was extracted by an experienced radiologist (11 years). Automatic classification of intrapulmonary lesions was performed by deep learning (VGG-like model). ResultsIn total, 4409 lesions were labeled (2746 METs (62.3 %), 1143 LNs (25.9%), 328 GC (7.4%), 192 GD (4.4%)). The model predicted instances of these classes for GD, GC or LN with a significant area under the receiver operating curve (ROC) of 0.66, 0.70 and 0.68, respectively (p-value <0.001). The performance of the algorithm was independent of imaging protocol (e.g. contrast enhancement, slice thickness, and reconstructed imaging kernel (soft versus sharp)) with AUC 0.65 for all. ConclusionsDeep learning can help to discriminate between intrapulmonary granulomatous disease, indeterminate calcified granulomas and intrapulmonary lymph nodes in anti-PD-1 treated melanoma patients. Further model development is needed to overcome the imbalanced “real clinical scenario” data to classify granulomatous disease in melanoma patients treated with anti-PD-1 immune checkpoint inhibitor blockade for implementation in the clinical workflow. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

Abstract 4500: Mechanisms of tumor-associated myeloid cells in modulating host immune microenvironment and metastatic progression

Abstract The immune checkpoint inhibitor blockade takes advantage of the specific receptor-ligand interactions between immune and tumor cells. However, the immunosuppressive microenvironment has been largely ignored, which likely contribute to low efficacy and resistance in immune therapies. Our studies demonstrate that TGF-β signaling in tumor-associated myeloid cells isessential in systemic immune suppression and metastatic progression. Using mouse models of breast cancer metastasis, we further uncover that miR130a and 145 are critical in regulating TGF-β signaling in myeloid cells. miR130a and 145 are down-regulated in these myeloid cells, leading to increased TGF-β RII. Ectopic expression of miR-130a and miR-145 in the myeloid cells decrease tumor metastasis. This is mediated through a downregulation of type 2 cytokines in myeloid cells and an increase in IFNgamma-producing cytotoxic CD8 T lymphocytes. Lastly, miR-130a and miR-145 mimics improve systemic anti-tumor immunity and inhibit metastasis in preclinical mouse models. Another important mechanism in myeloid-mediated immune suppression involves a decreased expression of Lamin A/C, nuclear lamina proteins that prominently interact with heterochromatin. Lamin A/C knockout in myeloid cells leads to H3K4me3-mediated upregulation of Gfi1 and C/EBPϵ,critical transcription factors responsible for granulocytic lineage differentiation. In addition, loss of Lamin A/C attenuates antigen-presentation and compromises host anti-tumor immunity. These mechanistic understandings provide options to reprogram tumor-associated myeloid cells by altering the cytokine milieu and metastatic microenvironment, thus enhancing host antitumor immunity. Citation Format: Hiroki Ishii, Christine Hollander, Tim Greten, Li Yang. Mechanisms of tumor-associated myeloid cells in modulating host immune microenvironment and metastatic progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4500.

Double Immune Checkpoint Inhibitor Blockade with Nivolumab and Ipilimumab with or without Azacitidine in Patients with Myelodysplastic Syndrome (MDS)

Double Immune Checkpoint Inhibitor Blockade with Nivolumab and Ipilimumab with or without Azacitidine in Patients with Myelodysplastic Syndrome (MDS)

Abstract 1156: New spontaneous and carcinogen-induced mouse-derived isograft (MDI) tumor models for immune therapeutic approaches

Abstract First findings in the late 1990s and the early 2000s, that blockade of immune checkpoint inhibitors (ICI) by antibodies could induce rejection of established tumors and induce immunity also to secondary exposure with these tumor cells, led again to a stronger focus of experimental studies on syngeneic tumor models in immunocompetent animals. The availability of such models, however, is mainly limited by the small number of genetically-modified (GEM) or long-term passaged cell line-derived tumor models. We here describe establishment and first characterization of a new type of animal tumor models, named Mouse-Derived-Isografts (MDI), from spontaneously appearing or carcinogen-induced syngeneic tumors in both sexes of various mouse strains (C3H/HeN, CBA/J, BALB/C, DBA/2N and C57BL/6N). The tumors were obtained from animals during long-term observation (≥ 1-2 years) of normally fed, otherwise untreated animals (spontaneous - sMDI) or during short-term observation (3-9 month) of once subcutaneously, intramuscularly, intraperitoneally or orally methylcholanthrene (MCA) or methyl-nitroso-urea (MNU) treated animals (carcinogen - cMDI). Criteria to perform a primary necropsy were critical weight loss, bad general conditions or externally observable tumor growth in monitored animals. At this first step, tissues were assessed only macroscopically, and conspicuous ones were transplanted (in PDX-like manner) as small pieces into sex-matched syngeneic animals. If possible tissue/tumor pieces were also frozen and stored in 10% DMSO freezing medium at -80°C. In a second step these re-transplanted, outgrowing tumors were amplified once again in syngeneic mice for freeze storing, and then the models were finally established by re-transplantation and testing outgrowth of the frozen stored tumor pieces in the syngeneic animals. The tumors appear phenotypically stable, as far as routine standard HE stained sections could show. General characteristics of these models are; they are primary spontaneous or carcinogen-induced tumors, of low passage number (&amp;lt;10), propagated as tissue pieces only in mice without tissue culturing, and thus with conserved original tumor characteristics as assessed microscopically and intra-tumoral immune cell populations analyzed by flow cytometry. Citation Format: Peter Jantscheff, Janette Beshay, Thomas Lemarchand, Cynthia Obodozie, Christoph Schaechtele, Holger Weber. New spontaneous and carcinogen-induced mouse-derived isograft (MDI) tumor models for immune therapeutic approaches [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1156.

The Role of Immune Checkpoint Inhibitors in Classical Hodgkin Lymphoma.

Hodgkin Lymphoma (HL) is a unique disease entity both in its pathology and the young patient population that it primarily affects. Although cure rates are high, survivorship can be linked with significant long-term morbidity associated with both chemotherapy and radiotherapy. The most significant recent advances have been with the use of the anti-CD30-drug conjugated antibody brentuximab vedotin (BV) and inhibitors of program death 1 (PD-1). HL is genetically wired to up-regulate program death ligand 1 (PD-L1) in >95% of cases, creating a state of so-called “T cell exhaustion”, which can be reversed with immune checkpoint-inhibitor blockade. The overall and complete response rates to PD-1 inhibitors in patients with relapsed or refractory HL are 70% and 20%, respectively, with a long median duration of response of ~16 months. In fact, PD-1 inhibitors can benefit a wide spectrum of relapsed HL patients, including some who have “progressive disease” by strict response criteria. We review the biology of HL, with a focus on the immune micro-environment and mechanisms of immune evasion. We also provide the rationale supporting the use of PD-1 inhibitors in HL and highlight some of the challenges of monitoring disease response in patients treated with this immunotherapy.

PD-1 immune checkpoint blockade promotes brain leukocyte infiltration and diminishes cyst burden in a mouse model of Toxoplasma infection

Tissue cysts, the hallmark of chronic Toxoplasma gondii infection, are predominantly located in the brain making clearance of the parasite difficult. Currently available anti-T. gondii drugs are ineffective on cysts and fail to prevent reactivation of latent toxoplasmosis. We examined whether abrogation of inhibitory signaling pathways that maintain T cells in an exhausted state can be exploited for treating T. gondii tissue cysts. By using a mouse model of chronic toxoplasmosis, we showed immune checkpoint blockade directed against the programmed death-1 (PD-1) pathway results in a significant reduction in brain cyst number (77% lower). We showed leukocyte infiltration (CD3+ T cells, CD8+ T cells, and CD11b + cells) in the leptomeninges, choroid plexus, and subependymal tissue, which are known routes of entry of immune cells into the brain, and in proximal brain parenchyma. Our study provides proof of concept for blockade of immune checkpoint inhibitors as a therapy for chronic toxoplasmosis and potentially for other brain pathogens.

Goals and objectives of the Italian Network for Tumor Biotherapy (NIBIT)

The explosion in the immuno-oncology field, exemplified by the clinical implementation of immune checkpoint inhibitor blockade and other immunotherapeutic strategies was quickly recognized by the Italian biomedical community, thanks to the networking activities of the Italian Network for Tumor Biotherapy (NIBIT), which has been active since 2004 in the diffusion of new scientific and clinical findings in the fields of tumor immunology and immunotherapy. Numerous activities of NIBIT have also helped to overcome the hurdles associated with the clinical implementation of cancer immune-biotherapeutic strategies at the national and international levels. Looking forward, a concerted interaction of NIBIT with existing European networks focused on cancer bio-immunotherapy will further contribute to the development of improved therapies in the immuno-oncology field. This Introduction briefly summarizes the history and objectives of NIBIT, as well as the current activities of the Network.