The perspective of immunotherapy: new molecules and new mechanisms of action in immune modulation

Ocular Inflammation Induced by Immune Checkpoint Inhibitors

Ocular immunotherapy-related adverse events (IRAEs), although rare, can be sight-threatening. Our objective was to analyze ocular IRAEs diagnosed in France from the marketing of immune checkpoint inhibitors (ICPIs) until June 2021 and to review the literature. We collected the cases of 28 patients (36 ocular IRAEs), occurring after an average of 17 weeks (±19). Forty-six percent of patients were treated for metastatic melanoma. Anti-PD1 agents were responsible for 57% of the IRAEs. Anterior uveitis was the most common (44%), followed by panuveitis (28%). Of 25 uveitis cases, 80% were bilateral and 60% were granulomatous. We found one case with complete Vogt-Koyanagi–Harada syndrome and one case of birdshot retinochoroidopathy. The other IRAEs were eight ocular surface disorders, one optic neuropathy, and one inflammatory orbitopathy. Seventy percent of the IRAEs were grade 3 according to the common terminology of AEs. ICPIs were discontinued in 60% of patients and 50% received local corticosteroids alone. The literature review included 230 uveitis cases, of which 7% were granulomatous. The distributions of ICPIs, cancer, and type of uveitis were similar to our cohort. Ocular IRAEs appeared to be easily controlled by local or systemic corticosteroids and did not require routine discontinuation of ICPIs. Further work is still warranted to define the optimal management of ocular IRAEs.

Natural killer cells and immune-checkpoint inhibitor therapy: Current knowledge and new challenges

The discovery of immune checkpoints (ICs) and the development of specific blockers to relieve immune effector cells from this inhibiting mechanism has changed the view of anti-cancer therapy. In addition to cytotoxic T lymphocyte antigen 4 (CTLA4) and programmed death 1 (PD1), classical ICs of T lymphocytes and recently described also on a fraction of natural killer (NK) cells, several NK cell receptors, including killer immunoglobulin-like inhibitory receptors (KIRs) and NGK2A, have been recognized as checkpoint members typical of the NK cell population. This offers the opportunity of a dual-checkpoint inhibition approach, targeting classical and non-classical ICs and leading to a synergistic therapeutic effect. In this review, we will overview and discuss this new perspective, focusing on the most relevant candidates for this role among the variety of potential NK ICs. Beside listing and defining classical ICs expressed also by NK cells, or non-classical ICs either on T or on NK cells, we will address their role in NK cell survival, chronic stimulation or functional exhaustion, and the potential relevance of this phenomenon on anti-tumor immune response. Furthermore, NK ICs will be proposed as possible new targets for the development of efficient combined immunotherapy, not forgetting the relevant concerns that may be raised on NK IC blockade. Finally, the impact of epigenetic drugs in such a complex therapeutic picture will be briefly addressed.

Immune checkpoints and cancer development: Therapeutic implications and future directions

Over the past few decades, different inhibitory receptors have been identified, which have played prominent roles in reducing anti-tumor immune responses. The role of immune checkpoint inhibitors in cancer was revealed by critical blockade of the cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death protein-1 (PD-1) checkpoints. Immune checkpoint inhibitors, including anti-PD-1 (nivolumab and pembrolizumab), anti-PD-L1 (Atezolizumab, avelumab, and duravulumab), and anti-CTLA-4 (ipilimumab, tremelimumab), are currently FDA-approved treatment options for a broad range of cancer types. However, regarding immunotherapy advances in recent years, most studies have been focused on finding the antibodies against other inhibitory immune checkpoints in the tumor microenvironment such as lymphocyte activation gene-3 (LAG-3), T cell immunoglobulin, and mucin domain 3 (TIM-3), B7-homolog 3 (B7-H3), V-domain immunoglobulin-containing suppressor of T-cell activation (VISTA), diacylglycerol kinase-α (DGK-α), T cell immunoglobulin and ITIM domain (TIGIT), and B and T lymphocyte attenuator (BTLA). This immune checkpoint exerts differential inhibitory impacts on various types of lymphocytes. The suppression of immune responses demonstrates a surprising synergy with PD-1. Therefore, most antibodies against these immune checkpoints are undertaking clinical trials for cancer immunotherapy of advanced solid tumors and hematologic malignancies. In this review, we will summarize recent findings of immune checkpoint and the role of monoclonal antibodies in cancer immunotherapy targeting these receptors.

Pembrolizumab-induced myasthenia gravis-like disorder, ocular myositis, and hepatitis: a case report

Introduction

Pembrolizumab and other immune checkpoint inhibitors are the emerging treatment for selected, high-grade malignancies. However, a small number of patients are unable to tolerate its adverse effects, leading to discontinuation of this potentially life-changing therapy. In this study, we present a case of high-grade urothelial carcinoma patient, who experienced neurocomplications during the first pembrolizumab administration. However, we were able to limit the adverse effect by concomitant use of low-dose oral steroids.

Case presentation

A 75-year-old Taiwanese female with high-grade urothelial carcinoma of the left ureter came to the neurology clinic with complaints of acute onset of bilateral ptosis 16 days after her first infusion of pembrolizumab. It was found that she developed complete bilateral ptosis and limited extraocular muscle movements. Myasthenia gravis-related antibodies and repetitive stimulation test were negative. We diagnosed her with pembrolizumab-induced myasthenia gravis-like disorder and myositis based on clinical symptoms and elevation of muscle enzymes. We commenced methylprednisolone pulse therapy followed by oral steroid therapy with gradual resolution of the symptoms. Three months later, the patient received a second cycle of pembrolizumab with low-dose oral steroids without any complications.

Conclusion

Pembrolizumab exerts its antitumor activity by interfering with the binding of programmed death 1 and its ligand, programmed death ligand 1. As a result, enhanced cytotoxic T cells can recognize tumor cells and induce cellular death. However, neurological complications may be severe and require prompt recognition and treatment. Our case demonstrated that concomitant use of low-dose steroids and pembrolizumab might prevent such complications.

Dual activity of PD-L1 targeted Doxorubicin immunoliposomes promoted an enhanced efficacy of the antitumor immune response in melanoma murine model

BACKGROUND

The immunomodulation of the antitumor response driven by immunocheckpoint inhibitors (ICIs) such as PD-L1 (Programmed Death Ligand-1) monoclonal antibody (α-PD-L1) have shown relevant clinical outcomes in a subset of patients. This fact has led to the search for rational combinations with other therapeutic agents such as Doxorubicin (Dox), which cytotoxicity involves an immune activation that may enhance ICI response. Therefore, this study aims to evaluate the combination of chemotherapy and ICI by developing Dox Immunoliposomes functionalized with monovalent-variable fragments (Fab') of α-PD-L1.

RESULTS

Immunoliposomes were assayed in vitro and in vivo in a B16 OVA melanoma murine cell line over-expressing PD-L1. Here, immune system activation in tumor, spleen and lymph nodes, together with the antitumor efficacy were evaluated. Results showed that immunoliposomes bound specifically to PD-L1⁺ cells, yielding higher cell interaction and Dox internalization, and decreasing up to 30-fold the IC₅₀, compared to conventional liposomes. This mechanism supported a higher in vivo response. Indeed, immunoliposomes promoted full tumor regression in 20% of mice and increased in 1 month the survival rate. This formulation was the only treatment able to induce significant (p < 0.01) increase of activated tumor specific cytotoxic T lymphocytes at the tumor site.

CONCLUSION

PD-L1 targeted liposomes encapsulating Dox have proved to be a rational combination able to enhance the modulation of the immune system by blocking PD-L1 and selectively internalizing Dox, thus successfully providing a dual activity offered by both, chemo and immune therapeutic strategies.

Development of a robust reporter gene assay for measuring the bioactivity of OX40-targeted therapeutic antibodies

OX40 plays a prominent role in the onset and development of solid tumors, and OX40-targeted monoclonal antibodies (mAbs) have entered clinical trials for various tumors. Bioactivity determination of therapeutic mAbs is of great significance in product quality, however, mechanism of action-based bioassays to determine the bioactivity of anti-OX40 mAbs is still lacking. Here, we established a reporter gene assay system based on two cell lines, namely Jurkat-OX40-NFκB-Luc which stably expresses NFκB-controlled luciferase, and Raji cells which inherently express FcγRs. In the model, FcγRs on Raji cells could crosslink the Fc of anti-OX40 mAbs, which leads to the further crosslinking between Fab of anti-OX40 mAbs and OX40 on Jurkat-OX40-NFκB-Luc cells. OX40 crosslinking could activate Jurkat-OX40-NFκB-Luc cells, and induce the expression of NFκB-controlled luciferase, the extent of which could reflect the bioactivity of anti-OX40 mAbs in a dose-dependent manner. After the optimization of various assay conditions, the validation of the cell-based bioassay showed good assay performance characteristics, including specificity, accuracy, precision, linearity, and stability. This innovative assay that is based on the OX40-NFκB pathway can be a powerful pool to measure the bioactivity of OX40-targeted mAbs.

PD1 expression and correlation with its ligands in oral cancer specimens and peripheral blood

OBJECTIVES

This study analyzed the expression of the PD1 receptor in tumor tissue and peripheral blood of oral squamous cell carcinoma (OSCC) patients, and correlated it with the PD1 ligands PD-L1 and PD-L2. The currently low response rates of checkpoint inhibitor treatment in OSCC could be increased by a better understanding of immune checkpoint biology. Despite evidence in the literature for upregulation of PD1 checkpoint ligands in OSCC tissue, there has been no correlation analysis of the PD1 receptor with its ligands in tissue specimens and peripheral blood of OSCC patients.

MATERIALS AND METHODS

An RT-qPCR analysis of PD1 mRNA expression was performed in oral cancer specimens, healthy mucosa, and corresponding blood samples. A cut-off point (COP) was determined and a chi-square (χ²) test was carried out. PD1 expression was correlated with previously reported PD-L1 and PD-L2 expression values using the Spearman test.

RESULTS

Tissue and blood specimens of 48 OSCC patients and 26 healthy individuals were analyzed. PD1 expression in OSCC specimens was significantly increased (p = 0.006) compared with healthy oral mucosa. PD1 overexpression in tissue samples showed a significant association with the presence of malignancy (p = 0.006). PD1 expression in tissue samples showed a significant positive correlation (p < 0.001) with the ligands PD-L1 and PD-L2. In contrast, there was no correlation between PD1 and its ligands in blood samples. However, there was a significant positive correlation (p < 0.001) between the ligands PD-L1 and PD-L2, both in tissue and blood samples.

CONCLUSIONS

Increased PD1 expression might be a manifestation of T-cell exhaustion in OSCC specimens, leading to immune tolerance. PD-L1/PD-L2-PD1 interaction may be a major mediator of local immunosuppression in OSCC, requiring advanced multimodal treatment protocols.

Antibody and antibody fragments for cancer immunotherapy

Antibody has become the most rapidly expanding class of pharmaceuticals for treating a wide variety of human diseases including cancers. Especially, with the fast development of cancer immunotherapy, antibody drugs have become the most promising therapeutic for curing cancers. Immune-mediated cell killing by antibodies including antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cell phagocytosis (ADCP) and complement-dependent cytotoxicity (CDC) as well as regulation of T cell function through immune checkpoint blockade. Due to the absence of Fc fragment, antibody fragments including single-chain variable fragments (scFvs) and single-domain antibodies (sdAds) are mainly applied in chimeric antigen receptors (CAR) T cell therapy for redirecting T cells to tumors and T cell activation by immune checkpoint blockade. In this review, the cancer immunity is first discussed. Then the principal mechanisms of antibody-based immunotherapy will be reviewed. Next, the antibody and antibody fragments applied for cancer immunotherapy will be summarized. Bispecific and multispecific antibodies and a combination of cancer immunotherapy with other tumor treatments will also be mentioned. Finally, an outlook and perspective of antibody-based cancer immunotherapy will be given. This review would provide a comprehensive guidance for the researchers who are interested in and intended to involve in the antibodies- or antibody fragments-based tumor immunity.

Silence of Hippo Pathway Associates with Pro-Tumoral Immunosuppression: Potential Therapeutic Target of Glioblastomas

The critical role of the Hippo pathway has been recently investigated in various cancers, but little is known about its role in glioblastoma (GBM). In order to evaluate the clinical relevance of the Hippo pathway in GBM, we generated a core gene expression signature from four different previously-established silence of Hippo pathway (SOH) signatures. Based on a newly generated core SOH signature, a SOH and active Hippo pathway (AH) was predicted in GBM samples from The Cancer Genome Atlas (TCGA) and validated in a separate cohort. A comparative analysis was performed on multi-panel genomic datasets from TCGA and the possible association of SOH with immune activity and epithelial mesenchymal transition was also evaluated. The SOH signature was associated with poor prognosis in GBM in both cohorts. Expression levels of CTGF and CYR61, the most reliable and well-known downstream targets of YAP1, were markedly increased in the SOH subgroup of GBM patients. SOH signature was strongly associated with a high immune signature score and mesenchymal features. Genes differentially expressed between SOH and AH groups revealed many markers for inhibitory immune checkpoints and M2-polarized macrophages were upregulated in the SOH subgroup, suggesting that SOH may induce the resistance of cancer cells to host immune response in GBM. In summary, SOH is significantly associated with the poor prognosis of GBM patients and is possibly mediated by pro-tumoral immunosuppression.

How microRNAs affect the PD-L1 and its synthetic pathway in cancer

Programmed cell death-ligand 1 (PD-L1) is a glycoprotein that is expressed on the cell surface of both hematopoietic and nonhematopoietic cells. PD-L1 play a role in the immune tolerance and protect self-tissues from immune system attack. Dysfunction of this molecule has been highlighted in the pathogenesis of tumors, autoimmunity, and infectious disorders. MicroRNAs (miRNAs) are endogenous molecules that are classified as small non-coding RNA with approximately 20-22 nucleotides (nt) length. The function of miRNAs is based on complementary interactions with target mRNA via matching completely or incompletely. The result of this function is decay of the target mRNA or preventing mRNA translation. In the past decades, several miRNAs have been discovered which play an important role in the regulation of PD-L1 in various malignancies. In this review, we discuss the effect of miRNAs on PD-L1 expression and consider the effect of miRNAs on the synthetic pathway of PD-L1, especially during cancers.

Prevalence and Clinical Patterns of Ocular Complications Associated With Anti-PD-1/PD-L1 Anticancer Immunotherapy

PURPOSE

Immune checkpoint inhibitors (ICI) targeting the programmed cell death protein 1 (PD-1), or its ligand PD-L1, are the mainstay of metastatic cancer treatment. Patients receiving these treatments may develop immune-related adverse events (irAEs). This study aimed to estimate the prevalence and describe the clinical patterns of moderate-to-severe ocular irAEs-associated with anti-PD-(L)1 treatment.

DESIGN

Prospective case series.

METHODS

This study included patients recruited via (1) a single-center prospective cohort and (2) a national pharmacovigilance registry between June 2014 and March 2018, and focused on patients with moderate-to-severe ocular irAEs following anti-PD-(L)1. All patients underwent a comprehensive ophthalmologic assessment. The main outcome measure was the prevalence of moderate-to-severe ocular irAEs.

RESULTS

Of a total of 745 patients included in the prospective cohort, 3 developed moderate-to-severe ocular irAEs, providing a prevalence of 0.4% and an incidence of 0.7 per 1000 patient-months of treatment. An additional 5 cases of moderate-to-severe ocular irAEs were reported through the national registry. From these 8 patients, 5 presented with intraocular inflammation, 2 with ocular surface disease, and 1 with orbital myopathy. Five patients (62.5%) experienced additional extraophthalmologic irAEs. Ocular irAEs led to permanent discontinuation of anti-PD-(L)1 in 4 patients. Treatment by local and/or systemic corticosteroids allowed resolution or control of the ocular symptoms in 7 of 8 patients.

CONCLUSION

Although uncommon, anti-PD-(L)1-associated ocular complications may be sight-threatening and lead to discontinuation of anti-PD-(L)1 treatments. Patients complaining of eye problems while receiving ICI treatment should immediately be seen by an ophthalmologist.

A new immune-nanoplatform for promoting adaptive antitumor immune response

Immunoliposomes (ILs), obtained with monoclonal antibodies (mAbs) decorating the liposome surface, are used for cancer treatment. These mAbs provide the recognition of molecules upregulated in cancer cells, like Programmed Death-Ligand 1 (PD-L1), an immune-checkpoint involved in tumor resistance, forming a complex that blocks this molecule and thereby, induces antitumor immune response. This mechanism introduces a new concept for ILs. ILs coupled to anti-PD-L1 or its Fab' fragment have been developed and in vitro/in vivo characterized. Factors such as coupling methods, PEG density and ligand size were optimized. In vitro data showed that Fab'-ILs displayed the highest PD-L1 cell interaction, correlating with a higher in vivo tumor accumulation and an increase of effector cytotoxic CD8⁺ T cells, providing tumor shrinkage and total regression in 20% of mice. Therefore, a novel immune-nanoplatform able to modulate the immune system has been developed, allowing the encapsulation of several agents for combinatorial therapies.

Polyaspartamide-based graft copolymers encapsulating iron oxide nanoparticles for imaging and fluorescence labelling of immune cells

Iron oxide nanoparticles (NPs) were encapsulated with polyaspartamide-based graft copolymers to bind and track the immune cells as imaging probes. Mono-disperse iron oxide NPs with a mean diameter of 10.7 nm were synthesized by the thermal decomposition method, and their shape and distribution were measured by electrophoretic light scattering and transmission electron microscopy. To enhance their biocompatibility, interfacial and hydrodynamic stability, and fluorescence detection, biodegradable polysuccinimide (PSI) grafted with several functional groups of octadecylamine (C18), ethanolamine (EA), ethylenediamine (EDA), 4-(N-maleimidomethyl) cyclohexane carboxylic acid N-hydroxysuccinimide ester (SMCC), and fluorescein isothiocyanate (FITC) was coated on the iron oxide NPs. The structure of the C18/EA/SMCC/FITC-g-PSI copolymer was confirmed using ¹H-NMR and FTIR spectroscopy, and its cell binding ability was investigated by flow cytometry and confocal laser scanning microscopy. The synthesized C18/EA/SMCC/FITC-g-PSI copolymer showed an excellent binding affinity to CD4+ T cells, and was highly biocompatible as the cell viability at the highest polymer concentration of 0.4 mg mL^-1 was greater than 85 and 75% after 24 and 48 h, respectively, from MTT assay.

Metabolomic profile of systemic sclerosis patients

Systemic sclerosis (SSc) is an autoimmune disease of unknown aetiology characterized by vascular lesions, immunological alterations and diffuse fibrosis of the skin and internal organs. Since recent evidence suggests that there is a link between metabolomics and immune mediated disease, serum metabolic profile of SSc patients and healthy controls was investigated by ¹H-NMR and GC-MS techniques. The results indicated a lower level of aspartate, alanine, choline, glutamate, and glutarate in SSc patients compared with healthy controls. Moreover, comparing patients affected by limited SSc (lcSSc) and diffuse SSc (dcSSc), 6 discriminant metabolites were identified. The multivariate analysis performed using all the metabolites significantly different revealed glycolysis, gluconeogenesis, energetic pathways, glutamate metabolism, degradation of ketone bodies and pyruvate metabolism as the most important networks. Aspartate, alanine and citrate yielded a high area under receiver-operating characteristic (ROC) curves (AUC of 0.81; CI 0.726–0.93) for discriminating SSc patients from controls, whereas ROC curve generated with acetate, fructose, glutamate, glutamine, glycerol and glutarate (AUC of 0.84; CI 0.7–0.98) discriminated between lcSSc and dcSSc. These results indicated that serum NMR-based metabolomics profiling method is sensitive and specific enough to distinguish SSc from healthy controls and provided a feasible diagnostic tool for the diagnosis and classification of the disease.

Current status and perspectives in immunotherapy for metastatic melanoma

Metastatic melanoma was the first malignancy in which immune checkpoint inhibitors demonstrated their successful efficacy. Currently, the knowledge on the interaction between the immune system and malignant disease is steadily increasing and new drugs and therapeutic strategies are overlooking in the clinical scenario. To provide a comprehensive overview of immune modulating drugs currently available in the treatment of melanoma as well as to discuss of possible future strategies in the metastatic melanoma setting, the present review aims at analyzing controversial aspects about the optimal immunomodulating treatment sequences, the search for biomarkers of efficacy of immunocheckpoint inhibitors, and innovative combinations of drugs currently under investigation.

mRNA Expression levels of genes involved in antitumor immunity: Identification of a 3-gene signature associated with prognosis of muscle-invasive bladder cancer

Immunotherapy for bladder cancer has given promising results. Here we aimed to evaluate the possible involvement and prognostic value of 33 genes involved in the immune response during bladder carcinogenesis. Expression levels were assessed by quantitative real-time RT-PCR in normal and tumor human bladder samples. Immunohistochemistry was performed to evaluate the protein expression of 2 genes and relation of the mRNA and protein levels was analyzed. Tumors were obtained from 154 patients (83 with muscle-invasive bladder cancer [MIBC] and 71 non-MIBC [NMIBC]) who underwent transurethral bladder resection or radical cystectomy between 2002 and 2006. All patients signed an informed consent. Results of molecular analyses were coupled with survival analyses. Overall, 25 genes (75.8%) were significantly overexpressed in MIBC and 15 (45.5%) were deregulated in NMIBC as compared with normal tissue. On multivariate analysis, risk of NMIBC recurrence was increased with high FOXP3/CD8 ratio and overexpression of OX40L (p = 0.016 and p = 0.0039, respectively). In MIBC, a molecular signature of 3 genes (OX40L, CD8 and TIGIT) was significantly associated with prognosis in terms of recurrence-free and overall survival (p = 0.0007 and p = 0.007). RT-PCR findings were confirmed by immunohistochemistry for CD8 and FOXP3, with high association between mRNA and protein levels. Finally, risk of recurrence of non-muscle-invasive bladder cancer was increased with high FOXP3/CD8 ratio and OX40L overexpression. We identified a 3 gene molecular signature associated with prognosis of muscle-invasive bladder cancer. These results confirm the useful role of immune checkpoints in bladder carcinogenesis and suggest targets for therapy.

A Phase I trial using local regional treatment, nonlethal irradiation, intratumoral and systemic polyinosinic-polycytidylic acid polylysine carboxymethylcellulose to treat liver cancer: in search of the abscopal effect

Purpose

To determine the safety of an approach to immunologically enhance local treatment of hepatocellular cancer (HCC) by combining nonlethal radiation, local regional therapy with intratumoral injection, and systemic administration of a potent Toll-like receptor (TLR) immune adjuvant.

Methods

Patients with HCC not eligible for liver transplant or surgery were subject to: 1) 3 fractions of 2-Gy focal nonlethal radiation to increase tumor antigen expression, 2) intra-/peri-tumoral (IT) injection of the TLR3 agonist, polyinosinic-polycytidylic acid polylysine carboxymethylcellulose (poly-ICLC), to induce an immunologic “danger” response in the tumor microenvironment with local regional therapy, and 3) systemic boosting of immunity with intramuscular poly-ICLC. Primary end points were safety and tolerability; secondary end points were progression-free survival (PFS) and overall survival (OS) at 6 months, 1 year, and 2 years.

Results

Eighteen patients with HCC not eligible for surgery or liver transplant were treated. Aside from 1 embolization-related severe adverse event, all events were ≤grade II. PFS was 66% at 6 months, 39% at 12 months, and 28% at 24 months. Overall 1-year survival was 69%, and 2-year survival 38%. In patients <60 years old, 2-year survival was 62.5% vs. 11.1% in patients aged >60 years (P<0.05). Several patients had prolonged PFS and OS.

Conclusion

Intra-tumoral injection of the TLR3 agonist poly-ICLC in patients with HCC is safe and tolerable when combined with local nonlethal radiation and local regional treatment. Further work is in progress to evaluate if this approach improves survival compared to local regional treatment alone and characterize changes in anticancer immunity.

Immunotherapy of colorectal cancer: new perspectives after a long path

Although significant therapeutic improvement has been achieved in the last 10 years, the survival of metastatic colorectal cancer patients remains in a range of 28 to 30 months. Presently, systemic treatment includes combination chemotherapy with oxaliplatin and/or irinotecan together with a backbone of 5-fluorouracil/levofolinate, alone or in combination with monoclonal antibodies to VEGFA (bevacizumab) or EGF receptor (cetuximab and panitumumab). The recent rise of immune checkpoint inhibitors in the therapeutic scenario has renewed scientific interest in the investigation of immunotherapy in metastatic colorectal cancer patients. According to our experience and view, here, we review the immunological strategies investigated for the treatment of this disease, including the use of tumor target-specific cancer vaccines, chemo-immunotherapy and immune checkpoint inhibitors.

Understanding the checkpoint blockade in lung cancer immunotherapy

Immunotherapies have changed the treatment strategy of some types of tumor including melanoma and, more recently, non-small-cell lung cancer (NSCLC). Immune checkpoints are crucial for the maintenance of self-tolerance and it is known that some tumors use checkpoint systems to evade antitumor immune response. The treatment of advanced NSCLC by immune-checkpoint blockade targeting the programmed cell death protein-1 (PD1/PDL1) and cytotoxic T-lymphocyte antigen 4 (CTLA4) pathways has led to significant clinical benefit either as monotherapy or in combination therapy. Moreover, checkpoint receptors such as lymphocyte activation gene 3 protein (LAG3), T-cell immunoglobulin mucin domain 3 (TIM3) and killer immunoglobulin-like receptors (KIRs) are also being investigated as potential immunotherapeutic targets. This review focuses on the mechanisms of action of the main checkpoint inhibitors in lung cancer and presents the most relevant results from preclinical and clinical studies on immune-based treatments.

New developments in the biology and the treatment of metastatic Merkel cell carcinoma

PURPOSE OF REVIEW

Patients with stage IIIB und IV metastatic Merkel cell carcinoma (mMCC), who are not suitable candidates for surgery or radiotherapy, are unlikely to achieve lasting remission or tumor control by chemo or targeted therapy. In the majority of cases, the tumor arises from viral carcinogenesis associated with the Merkel cell polyomavirus (MCPyV). In MCPyV-negative tumors with a presumable ultraviolet carcinogenesis, a high mutational burden resulting in neoantigens was discovered. In two phase II clinical trials in either the first or second-line setting, a high response rate was observed for immunotherapies with antibodies blocking the programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) immune checkpoints.

RECENT FINDINGS

The response rate was 56% with the anti-PD-1 inhibitor pembrolizumab as a first-line and 32% with the anti-PD-L1 antibody avelumab used as second-line therapy. Both treatments were well tolerated. Treatment response was rapid and in most cases maintained during follow-up, which, however, is still rather short. Whether the MCPyV or the PD-L1 status is predictive for treatment response and progression-free survival is still ambiguous. Additionally, clinical criteria for patient selection for immunotherapy of mMCC have not yet been defined.

SUMMARY

PD-1/PD-L1 inhibition can be regarded as new first-line therapy for patients with mMCC not amendable by surgery and/or radiation.

Understanding Immune Checkpoint Inhibitors for Effective Patient Care

BACKGROUND

Immune checkpoint inhibitors represent a paradigm change in the treatment of melanoma and other advanced cancers. These agents manipulate key immune-regulating pathways to restore immune responses against tumors. The success of this approach is demonstrated by ipilimumab (Yervoy®) for the treatment of advanced melanoma, with improvement in three-year survival rates of about 20%. Newer checkpoint inhibitors targeting the programmed death-1 (PD-1) pathway have been approved and may have higher response rates and improved tolerability.

OBJECTIVES

This article aims to educate nurses and increase their comfort level with these new therapies.

METHODS

The mechanism of action of immune checkpoint inhibitors is reviewed, and insight is provided on how nurses can use this knowledge to more effectively care for patients receiving these therapies.

FINDINGS

The use of immuno-oncology agents is increasing. Oncology nurses must understand the basic immune mechanism of action responsible for the novel toxicity profile characterized by immune-related adverse events (irAEs) and clinical response patterns. Managing irAEs with immune checkpoint inhibitors is not necessarily more difficult than with conventional agents, but a difference does exist. Nurses and other healthcare providers must consider the underlying cause of toxicity with immune checkpoint inhibitors when making management decisions.

Immune Checkpoint Inhibitors: Therapeutic Tools for Breast Cancer

Breast cancer is one of the major threats to female health, and its incidence is rapidly increasing in many countries. Currently, breast cancer is treated with surgery, followed by chemotherapy or radiation therapy, or both. However, a substantial proportion of breast cancer patients might have a risk for local relapse that leads to recurrence of their disease and/or metastatic breast cancer. Therefore searching for new and potential strategies for breast cancer treatment remains necessary. Immunotherapy is an attractive and promising approach that can exploit the ability of the immune system to identify and destroy tumors and thus prevent recurrence and metastatic lesions. The most promising and attractive approach of immunotherapeutic research in cancer is the blockade of immune checkpoints. In this review, we discuss the potential of certain inhibitors of immune checkpoints, such as antibodies targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed death 1 (PD-1) and lymphocyte activation gene-3 (LAG-3), in breast cancer therapeutics. Immune checkpoint inhibitors may represent future standards of care for breast cancer as monotherapy or combined with standard therapies.

Checkpoint Inhibition of KIR2D with the Monoclonal Antibody IPH2101 Induces Contraction and Hyporesponsiveness of NK Cells in Patients with Myeloma

PURPOSE

Immune checkpoint inhibitors have recently revolutionized cancer immunotherapy. On the basis of data showing KIR-ligand mismatched natural killer (NK) cells reduce the risk of leukemia and multiple myeloma relapse following allogeneic hematopoietic stem cell transplantation, investigators have developed a checkpoint inhibition antibody that blocks KIR on NK cells. Although in vitro studies suggest the KIR2D-specific antibody IPH2101 induces KIR-ligand mismatched tumor killing by NK cells, our single-arm phase II clinical trial in patients with smoldering multiple myeloma was prematurely terminated due to lack of clinical efficacy. This study aimed at unveiling the underlying mechanisms behind the lack of clinical efficacy.

EXPERIMENTAL DESIGN

Treatment-naïve patients received an intravenous infusion of 1 mg/kg IPH2101 every other month for up to a year. Peripheral blood was collected at baseline and 24 hours after first infusion, followed by weekly samples for the first month and monthly samples thereafter. NK cell phenotype and function was analyzed using high-resolution flow cytometry.

RESULTS

Unexpectedly, infusion of IPH2101 resulted in rapid reduction in both NK cell responsiveness and KIR2D expression on the NK cell surface. In vitro assays revealed KIR2D molecules are removed from the surface of IPH2101-treated NK cells by trogocytosis, with reductions in NK cell function directly correlating with loss of free KIR2D surface molecules. Although IPH2101 marginally augmented the antimyeloma cytotoxicity of remaining KIR2D^dull patient NK cells, the overall response was diminished by significant contraction and reduced function of KIR2D-expressing NK cells.

CONCLUSIONS

These data raise concerns that the unexpected biological events reported in this study could compromise antibody-based strategies designed at augmenting NK cell tumor killing via checkpoint inhibition. Clin Cancer Res; 22(21); 5211-22. ©2016 AACRSee related commentary by Felices and Miller, p. 5161.

Trastuzumab emtansine (T-DM1) renders HER2+ breast cancer highly susceptible to CTLA-4/PD-1 blockade

Targeted drug delivery with antibody-drug conjugates such as the HER2-directed ado-trastuzumab emtansine (T-DM1) has emerged as a powerful strategy for cancer therapy. We show that T-DM1 is particularly effective in eliciting antitumor immunity in patients with early breast cancer (WSG-ADAPT trial) and in a HER2-expressing orthotopic tumor model. In the latter, despite primary resistance to immunotherapy, combined treatment with T-DM1 and anti-CTLA-4/PD-1 (cytotoxic T lymphocyte-associated protein-4/programmed cell death protein-1) was curative because it triggered innate and adaptive immunity. Tumor rejection was accompanied by massive T cell infiltration, TH1 (T helper 1) cell polarization, and, notably, a substantial increase in regulatory T cells. Depletion of regulatory T cells resulted in inflammation and tissue damage, implying their essential role in protecting the host during therapy. This study provides insights into the mechanisms of T-DM1's therapeutic activity and a rationale for potential therapeutic combination strategies with immunotherapy.

Endostatin enhances antitumor effect of tumor antigen-pulsed dendritic cell therapy in mouse xenograft model of lung carcinoma

Objective

To investigate the antitumor effect of endostatin combined with tumor antigen-pulsed dendritic cell (DC)-T cell therapy on lung cancer.

Methods

Transplanted Lewis lung cancer (LLC) models of C57BL/6 mice were established by subcutaneous injection of LLC cells in left extremity axillary. Tumor antigen-pulsed DC-T cells from spleen cells and bone of mice were cultured in vitro. Tumor-bearing mice were randomly divided into three groups, including DC-T+endostatin group, DC-T group, and phosphate-buffered saline (PBS) control group. Microvessel density (MVD) of tumor tissue in tumor-bearing mice was determined by immunohistochemistry (IHC). The expressions of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α) were determined by Western blotting and IHC staining. The proportions of CD8+ T cells, mature dendritic cells (mDC), tumor-associated macrophages [TAM (M1/M2)], and myeloid-derived suppressor cells (MDSC) in suspended cells of tumor tissue were determined by flow cytometry. The expressions of interleukin (IL)-6, IL-10, IL-17, transforming growth factor-β (TGF-β) and interferon-γ (IFN-γ) in suspended cells of tumor tissue were detected by enzyme-linked immune sorbent assay (ELISA).

Results

DC-T cells combined with endostatin remarkably suppressed tumor growth. MVD of mice in DC-T+endostatin group was significantly lower than that of the control group and DC-T monotherapy group. The expressions of VEGF, IL-6 and IL-17 in tumors were markedly decreased, but IFN-γ and HIF-1α increased after treating with DC-T cells combined with endostatin, compared to control group and DC-T group. In the DC-T+endostatin group, the proportions of MDSC and TAM (M2 type) were significantly decreased, mDC and TAM (M1 type) were up-regulated, and CD8+ T cells were recruited to infiltrate tumors, in contrast to PBS control and DC-T monotherapy. DC-T cells combined with endostatin potently reduced the expressions of IL-6, IL-10, TGF-β and IL-17 in tumor tissue, and enhanced the expression of IFN-γ.

Conclusions

The study indicated the synergic antitumor effects between endostatin and tumor antigen-pulsed DC-T cells, which may be a prospective therapy strategy to achieve potent antitumor effects on lung cancer.

Fractionated Radiotherapy with 3 x 8 Gy Induces Systemic Anti-Tumour Responses and Abscopal Tumour Inhibition without Modulating the Humoral Anti-Tumour Response

Accumulating evidence indicates that fractionated radiotherapy (RT) can result in distant non-irradiated (abscopal) tumour regression. Although preclinical studies indicate the importance of T cells in this infrequent phenomenon, these studies do not preclude that other immune mechanisms exhibit an addition role in the abscopal effect. We therefore addressed the question whether in addition to T cell mediated responses also humoral anti-tumour responses are modulated after fractionated RT and whether systemic dendritic cell (DC) stimulation can enhance tumour-specific antibody production. We selected the 67NR mammary carcinoma model since this tumour showed spontaneous antibody production in all tumour-bearing mice. Fractionated RT to the primary tumour was associated with a survival benefit and a delayed growth of a non-irradiated (contralateral) secondary tumour. Notably, fractionated RT did not affect anti-tumour antibody titers and the composition of the immunoglobulin (Ig) isotypes. Likewise, we demonstrated that treatment of tumour-bearing Balb/C mice with DC stimulating growth factor Flt3-L did neither modulate the magnitude nor the composition of the humoral immune response. Finally, we evaluated the immune infiltrate and Ig isotype content of the tumour tissue using flow cytometry and found no differences between treatment groups that were indicative for local antibody production. In conclusion, we demonstrate that the 67NR mammary carcinoma in Balb/C mice is associated with a pre-existing antibody response. And, we show that in tumour-bearing Balb/C mice with abscopal tumour regression such pre-existing antibody responses are not altered upon fractionated RT and/or DC stimulation with Flt3-L. Our research indicates that evaluating the humoral immune response in the setting of abscopal tumour regression is not invariably associated with therapeutic effects.

Concomitant targeting of programmed death-1 (PD-1) and CD137 improves the efficacy of radiotherapy in a mouse model of human BRAFV600-mutant melanoma

T cell checkpoint blockade with antibodies targeting programmed cell death (ligand)-1 (PD-1/PD-L1) and/or cytotoxic T lymphocyte-antigen 4 (CTLA-4) has improved therapy outcome in melanoma patients. However, a considerable proportion of patients does not benefit even from combined α-CTLA-4 and α-PD-1 therapy. We therefore examined to which extent T cell (co)stimulation and/or stereotactic body radiation therapy (SBRT) could further enhance the therapeutic efficacy of T cell checkpoint blockade in a genetically engineered mouse melanoma model that is driven by PTEN-deficiency, and BRAFV600 mutation, as in human, but lacks the sporadic UV-induced mutations. Tumor-bearing mice were treated with different combinations of immunomodulatory antibodies (α-CTLA-4, α-PD-1, α-CD137) or interleukin-2 (IL-2) alone or in combination with SBRT. None of our immunotherapeutic approaches (alone or in combination) had any anti-tumor efficacy, while SBRT alone delayed melanoma outgrowth. However, α-CD137 combined with α-PD-1 antibodies significantly enhanced the anti-tumor effect of SBRT, while the anti-tumor effect of SBRT was not enhanced by interleukin-2, or the combination of α-CTLA-4 and α-PD-1. We conclude that α-CD137 and α-PD-1 antibodies were most effective in enhancing SBRT-induced tumor growth delay in this mouse melanoma model, outperforming the ability of IL-2, or the combination of α-CTLA-4 and α-PD-1 to synergize with SBRT. Given the high mutational load and increased immunogenicity of human melanoma with the same genotype, our findings encourage testing α-CD137 and α-PD-1 alone or in combination with SBRT clinically, particularly in patients refractory to α-CTLA-4 and/or α-PD-1 therapy.

Dendritic Cell-Secreted Cytotoxic T-Lymphocyte-Associated Protein-4 Regulates the T-cell Response by Downmodulating Bystander Surface B7

The remarkable functional plasticity of professional antigen-presenting cells (APCs) allows the adaptive immune system to respond specifically to an incredibly diverse array of potential pathogenic insults; nonetheless, the specific molecular effectors and mechanisms that underpin this plasticity remain poorly characterized. Cytotoxic T-lymphocyte-associated protein-4 (CTLA-4), the target of the blockbuster cancer immunotherapeutic ipilimumab, is one of the most well-known and well-studied members of the B7 superfamily and negatively regulates T cell responses by a variety of known mechanisms. Although CTLA-4 is thought to be expressed almost exclusively among lymphoid lineage hematopoietic cells, a few reports have indicated that nonlymphoid APCs can also express the CTLA-4 mRNA transcript and that transcript levels can be regulated by external stimuli. In this study, we substantially build upon these critical observations, definitively demonstrating that mature myeloid lineage dendritic cells (DC) express significant levels of intracellular CTLA-4 that they constitutively secrete in microvesicular structures. CTLA-4(+) microvesicles can competitively bind B7 costimulatory molecules on bystander DC, resulting in downregulation of B7 surface expression with significant functional consequences for downstream CD8(+) T-cell responses. Hence, the data indicate a previously unknown role for DC-derived CTLA-4 in immune cell functional plasticity and have significant implication for the design and implementation of immunomodulatory strategies intended to treat cancer and infectious disease.

Immune checkpoint inhibition in ovarian cancer

Recent studies have shown that tumor cells acquire escape mechanisms to evade host immunity in the tumor microenvironment. Two key immune checkpoint pathways mediated by immunosuppressive co-signaling, the first via programmed cell death 1 (PD-1) and PD-1 ligand 1 (PD-1/PD-L1) and the second via CTLA-4 and B7 (CTLA-4/B7), have been previously described. Several clinical trials have revealed an outstanding anti-tumor efficacy of immune checkpoint inhibitors (anti-CTLA-4 antibody, anti-PD-1 antibody and/or anti-PD-L1 antibody) in patients with various types of solid malignancies, including non-small cell lung cancer, melanoma, renal cell cancer and ovarian cancer. In this review, we examine pre-clinical studies that described the local immune status and immune checkpoint signals in ovarian cancer, highlight recent clinical trials that evaluated immune checkpoint inhibitors against ovarian cancer and discuss the clinical issues regarding immune checkpoint inhibitors.

Dendritic cells and pluripotency: unlikely allies in the pursuit of immunotherapy

As the fulcrum on which the balance between the opposing forces of tolerance and immunity has been shown to pivot, dendritic cells (DC) hold significant promise for immune intervention in a variety of disease states. Here we discuss how the directed differentiation of human pluripotent stem cells may address many of the current obstacles to the use of monocyte-derived DC in immunotherapy, providing a novel source of previously inaccessible DC subsets and opportunities for their scale-up, quality control and genetic modification. Indeed, given that it is the immunological legacy DC leave behind that is of therapeutic value, rather than their persistence per se, we propose that immunotherapy should serve as an early target for the clinical application of pluripotent stem cells.

Checkpoint inhibitors in bladder and renal cancers: results and perspectives

The field of immunotherapy in urinary malignancy is expanding in several directions and checkpoint inhibitors are leading the way. The aim of this report is to highlight the efficacy and safety profile of the two classes of molecules, anti-cytotoxic T-lymphocyte antigen-4 and anti-programmed death receptor-1/programmed death ligand type 1, that are under investigation and represent potential candidates to be used in the near future for the management of bladder and renal cell cancer. The preliminary results as well as the future perspectives of this novel immunotherapy are analyzed. Novel immune checkpoint targets are reviewed as well.

Sunitinib pretreatment improves tumor-infiltrating lymphocyte expansion by reduction in intratumoral content of myeloid-derived suppressor cells in human renal cell carcinoma

Targeted therapy with sunitinib, pazopanib or everolimus has improved treatment outcome for patients with metastatic renal cell carcinoma patients (RCC). However, despite considerable efforts in sequential or combined modalities, durable remissions are rare. Immunotherapy like cytokine therapy with interleukin-2, T cell checkpoint blockade or adoptive T cell therapies can achieve long-term benefit and even cure. This raises the question of whether combining targeted therapy with immunotherapy could also be an effective treatment option for RCC patients. Sunitinib, one of the most frequently administered therapeutics in RCC patients has been implicated in impairing T cell activation and proliferation in vitro. In this work, we addressed whether this notion holds true for expansion of tumor-infiltrating lymphocytes (TILs) in sunitinib-treated patients. We compared resected primary RCC tumor material of patients pretreated with sunitinib with resection specimen from sunitinib-naïve patients. We found improved TIL expansion from sunitinib-pretreated tumor digests. These TIL products contained more PD-1 expressing TIL, while the regulatory T cell infiltration was not altered. The improved TIL expansion was associated with reduced intratumoral myeloid-derived suppressor cell (MDSC) content. Depletion of MDSCs from sunitinib-naïve RCC tissue-digest improved TIL expansion, proving the functional relevance of the MDSC alteration by sunitinib. Our in vivo results do not support previous in vitro observations of sunitinib inhibiting T cell function, but do provide a possible rationale for the combination of sunitinib with immunotherapy.

Curing advanced melanoma by 2025

PURPOSE OF REVIEW

To outline the most urgent challenges in the management of advanced melanoma.

RECENT FINDINGS

Considerable progress in targeted and immunotherapy of advanced melanoma has opened a perspective for a cure if all molecular and medical information is integrated in a rational precision treatment algorithm.

SUMMARY

Bioinformatics and system biology approaches will be needed to deal with omics databases. The support of patient advocacy groups may help to increase the acceptance of large scale, routine biobanking.

Autoimmune lymphocytic hypophysitis in association with autoimmune eye disease and sequential treatment with infliximab and rituximab

INTRODUCTION

Autoimmune lymphocytic hypophysitis associates predominantly with other autoimmune endocrinopathies and is most commonly treated with glucocorticoids and/or decompressive pituitary surgery. Here we report a new association and treatment modality for lymphocytic hypophysitis.

METHODS

A 52-year-old woman presented with scleritis, uveitis, facial palsy, and central diabetes insipidus, accompanied by thickened pituitary stalk and enlarged pituitary on cranial MRI. Neurosarcoidosis was suspected and treatment with glucocorticoids and methotrexate initiated. Since symptoms persisted, infliximab (a monoclonal antibody that antagonizes tumor necrosis factor alpha) was added to her regimen. The patient initially improved but after 6 months developed recurrent pituitary enlargement, bilateral optic neuritis, and panhypopituitarism. To ascertain the nature of the pituitary lesion, she underwent transsphenoidal biopsy, which revealed lymphocytic hypophysitis with numerous CD20 positive B lymphocytes. The pathological finding suggested to us that administration of rituximab (a monoclonal antibody that lyzes B cells expressing CD20) could be useful. Following two courses of rituximab, the pituitary mass resolved and the corticotroph axis partially recovered. The patient has remained in remission during 3 years of follow up.

CONCLUSION

This is the first report of hypophysitis occurring with the triad of scleritis, uveitis, and optic neuritis, as well as the first immunotherapy based on the sequential use of infliximab and rituximab.

Combination of Id2 Knockdown Whole Tumor Cells and Checkpoint Blockade: A Potent Vaccine Strategy in a Mouse Neuroblastoma Model

Tumor vaccines have held much promise, but to date have demonstrated little clinical success. This lack of success is conceivably due to poor tumor antigen presentation combined with immuno-suppressive mechanisms exploited by the tumor itself. Knock down of Inhibitor of differentiation protein 2 (Id2-kd) in mouse neuroblastoma whole tumor cells rendered these cells immunogenic. Id2-kd neuroblastoma (Neuro2a) cells (Id2-kd N2a) failed to grow in most immune competent mice and these mice subsequently developed immunity against further wild-type Neuro2a tumor cell challenge. Id2-kd N2a cells grew aggressively in immune-compromised hosts, thereby establishing the immunogenicity of these cells. Therapeutic vaccination with Id2-kd N2a cells alone suppressed tumor growth even in established neuroblastoma tumors and when used in combination with immune checkpoint blockade eradicated large established tumors. Mechanistically, immune cell depletion studies demonstrated that while CD8+ T cells are critical for antitumor immunity, CD4+ T cells are also required to induce a sustained long-lasting helper effect. An increase in number of CD8+ T-cells and enhanced production of interferon gamma (IFNγ) was observed in tumor antigen stimulated splenocytes of vaccinated mice. More importantly, a massive influx of cytotoxic CD8+ T-cells infiltrated the shrinking tumor following combined immunotherapy. These findings show that down regulation of Id2 induced tumor cell immunity and in combination with checkpoint blockade produced a novel, potent, T-cell mediated tumor vaccine strategy.

Radiation triggering immune response and inflammation

Radiation therapy (RT) is a well-established but still under optimization branch of Cancer Therapy (CT). RT uses electromagnetic waves or charged particles in order to kill malignant cells, by accumulating the energy onto these cells. The issue at stake for RT, as well as for any other Cancer Therapy technique, is always to kill only cancer cells, without affecting the surrounding healthy ones. This perspective of CT is usually described under the terms "specificity" and "selectivity". Specificity and selectivity are the ideal goal, but the ideal is never entirely achieved. Thus, in addition to killing healthy cells, changes and effects are observed in the immune system after irradiation. In this review, we mainly focus on the effects of ionizing radiation on the immune system and its components like bone marrow. Additionally, we are interested in the effects and benefits of low-dose ionizing radiation on the hematopoiesis and immune response. Low dose radiation has been shown to induce biological responses like inflammatory responses, innate immune system activation and DNA repair (adaptive response). This review reveals the fact that there are many unanswered questions regarding the role of radiation as either an immune-activating (low dose) or immunosuppressive (high dose) agent.

Several immune escape patterns in non-Hodgkin's lymphomas

Follicular Lymphomas (FL) and diffuse large B cell lymphomas (DLBCL) must evolve some immune escape strategy to develop from lymphoid organs, but their immune evasion pathways remain poorly characterized. We investigated this issue by transcriptome data mining and immunohistochemistry (IHC) of FL and DLBCL lymphoma biopsies. A set of genes involved in cancer immune-evasion pathways (Immune Escape Gene Set, IEGS) was defined and the distribution of the expression levels of these genes was compared in FL, DLBCL and normal B cell transcriptomes downloaded from the GEO database. The whole IEGS was significantly upregulated in all the lymphoma samples but not in B cells or other control tissues, as shown by the overexpression of the PD-1, PD-L1, PD-L2 and LAG3 genes. Tissue microarray immunostainings for PD-1, PD-L1, PD-L2 and LAG3 proteins on additional biopsies from 27 FL and 27 DLBCL patients confirmed the expression of these proteins. The immune infiltrates were more abundant in FL than DLBCL samples, and the microenvironment of FL comprised higher rates of PD-1⁺ lymphocytes. Further, DLBCL tumor cells comprised a higher proportion of PD-1+, PD-L1⁺, PD-L2⁺ and LAG3⁺ lymphoma cells than the FL tumor cells, confirming that DLBCL mount immune escape strategies distinct from FL. In addition, some cases of DLBCL had tumor cells co-expressing both PD-1, PD-L1 and PD-L2. Among the DLBCLs, the activated B cell (ABC) subtype comprised more PD-L1⁺ and PD-L2⁺ lymphoma cells than the GC subtype. Thus, we infer that FL and DLBCL evolved several pathways of immune escape.

Novel and emerging targeted-based cancer therapy agents and methods

After several decades of uncovering the cancer features and following the improvement of therapeutic agents, however cancer remains as one of the major reasons of mortality. Chemotherapy is one of the main treatment options and has significantly improved the overall survival of cancer patients, but chemotherapeutic agents are highly toxic for normal cells. Therefore, there is a great unmet medical need to develop new therapeutic principles and agents. Targeted-based cancer therapy (TBCT) agents and methods have revolutionized the cancer treatment efficacy. Monoclonal antibodies (mAbs) and small molecule inhibitors (SMIs) are among the most effective agents of TBCT. These drugs have improved the prognosis and survival of cancer patients; however, the therapeutic resistance has subdued the effects. Several mechanisms lead to drug resistance such as mutations in the drug targets, activation of compensatory pathways, and intrinsic or acquired resistance of cancer stem cells. Therefore, new modalities, improving current generation of inhibitors and mAbs, and optimizing the combinational therapy regimens are necessary to decrease the current obstacles in front of TBCT. Moreover, the success of new TBCT agents such as mAbs, SMIs, and immunomodulatory agents has sparked further therapeutic modalities with novel targets to inhibit. Due to the lack of cumulative information describing different agents and methods of TBCT, this review focuses on the most important agents and methods of TBCT that are currently under investigation.

Chemokine receptor-specific antibodies in cancer immunotherapy: achievements and challenges

The 1990s brought a burst of information regarding the structure, expression pattern, and role in leukocyte migration and adhesion of chemokines and their receptors. At that time, the FDA approved the first therapeutic antibodies for cancer treatment. A few years later, it was reported that the chemokine receptors CXCR4 and CCR7 were involved on directing metastases to liver, lung, bone marrow, or lymph nodes, and the over-expression of CCR4, CCR6, and CCR9 by certain tumors. The possibility of inhibiting the interaction of chemokine receptors present on the surface of tumor cells with their ligands emerged as a new therapeutic approach. Therefore, many research groups and companies began to develop small molecule antagonists and specific antibodies, aiming to neutralize signaling from these receptors. Despite great expectations, so far, only one anti-chemokine receptor antibody has been approved for its clinical use, mogamulizumab, an anti-CCR4 antibody, granted in Japan to treat refractory adult T-cell leukemia and lymphoma. Here, we review the main achievements obtained with anti-chemokine receptor antibodies for cancer immunotherapy, including discovery and clinical studies, proposed mechanisms of action, and therapeutic applications.

Dendritic Cell-Derived Exosomes may be a Tool for Cancer Immunotherapy by Converting Tumor Cells into Immunogenic Targets

Dendritic cells (DCs) have been attracting attention in cancer immunotherapy because of their role in inducing and modulating effective immune responses. Besides the direct contact with other cell types and the secretion of cytokines, it is becoming clear that nanovesicles, such as exosomes (Exo), secreted by DCs also have a role in their function. Conversely, tumor-derived Exo carry antigens and have been used as a source of specific stimulus for the immune response against tumors. At the same time, several works have shown that different cells types incorporate DC-derived Exo (DC-Exo), resulting in modifications of their phenotype and function. Since DC-Exo carry many of the immune function-associated molecules of DCs, their incorporation by tumor cells could turn tumor cells into immunogenic targets. We have, therefore, treated human breast adenocarcinoma cells (SK-BR-3) with DCs-Exo and used these to stimulate previously SK-BR-3-primed CD3⁺ T-cells. Sensitized T-cells cultured with DC-Exo-treated tumor cells showed a significantly higher percentage of IFN-γ-secreting cells (as measured by ELISPOT), when compared to the frequency of cells responding to non-DC-Exo-treated cells. These data show that the incorporation of DC-Exo by the tumor cells increased their ability to activate T-cells for a possibly more effective response, thus showing that DC-Exo may become another tool in cancer immunotherapy.

Could mycobacterial Hsp70-containing fusion protein lead the way to an affordable therapeutic cancer vaccine?

Cancer vaccine development efforts have recently gained momentum, but most vaccines showing clinical impact in human trials tend to be based on technology approaches that are very costly and difficult to produce at scale. With the projected doubling of the incidence of cancer and its related cost of care in the U.S. over the next two decades, the widespread clinical use of such vaccines will prove difficult to justify. Heat shock protein-based vaccines have shown the potential to elicit clinically meaningful immunologic responses in cancer, but the predominant development approach - heat shock protein-peptide complexes derived from a patient's own tumor - face similar challenges of cost and scalability. New innovative modalities for deploying heat shock proteins in cancer vaccines may open the door to vaccines that can generate potent cytotoxic responses against multiple tumor targets and can be made in a cost-effective and scalable manner.