PD-1 blockade by CT-011, anti-PD-1 antibody, enhances ex vivo T-cell responses to autologous dendritic cell/myeloma fusion vaccine

Strategies to enhance the therapeutic efficacy of anti-PD-1 antibody, anti-PD-L1 antibody and anti-CTLA-4 antibody in cancer therapy

Although immune checkpoint inhibitors (anti-PD-1 antibody, anti-PD-L1 antibody, and anti-CTLA-4 antibody) have displayed considerable success in the treatment of malignant tumors, the therapeutic effect is still unsatisfactory for a portion of patients. Therefore, it is imperative to develop strategies to enhance the effect of these ICIs. Increasing evidence strongly suggests that the key to this issue is to transform the tumor immune microenvironment from a state of no or low immune infiltration to a state of high immune infiltration and enhance the tumor cell-killing effect of T cells. Therefore, some combination strategies have been proposed and this review appraise a summary of 39 strategies aiming at enhancing the effectiveness of ICIs, which comprise combining 10 clinical approaches and 29 foundational research strategies. Moreover, this review improves the comprehensive understanding of combination therapy with ICIs and inspires novel ideas for tumor immunotherapy.

Enhancing Dendritic Cell Cancer Vaccination: The Synergy of Immune Checkpoint Inhibitors in Combined Therapies

Dendritic cell (DC) cancer vaccines are a promising therapeutic approach, leveraging the immune system to fight tumors. These vaccines utilize DCs' ability to present tumor-associated antigens to T cells, triggering a robust immune response. DC vaccine development has progressed through three generations. The first generation involved priming DCs with tumor-associated antigens or messenger RNA outside the body, showing limited clinical success. The second generation improved efficacy by using cytokine mixtures and specialized DC subsets to enhance immunogenicity. The third generation used blood-derived DCs to elicit a stronger immune response. Clinical trials indicate that cancer vaccines have lower toxicity than traditional cytotoxic treatments. However, achieving significant clinical responses with DC immunotherapy remains challenging. Combining DC vaccines with immune checkpoint inhibitors (ICIs), such as anticytotoxic T-lymphocyte Antigen 4 and antiprogrammed death-1 antibodies, has shown promise by enhancing T-cell responses and improving clinical outcomes. These combinations can transform non-inflamed tumors into inflamed ones, boosting ICIs' efficacy. Current research is exploring new checkpoint targets like LAG-3, TIM-3, and TIGIT, considering their potential with DC vaccines. Additionally, engineering T cells with chimeric antigen receptors or T-cell receptors could further augment the antitumor response. This comprehensive strategy aims to enhance cancer immunotherapy, focusing on increased efficacy and improved patient survival rates.

The role of immune checkpoint inhibitors: Variable number of tandem repeat (VNTR) polymorphism in the second exon of the P-selectin glycoprotein ligand-1 (PSGL-1) gene polymorphism in multiple myeloma

Somatic mutations and polymorphisms may play a role in multiple myeloma (MM) susceptibility and survival. One of the immune checkpoint inhibitors is P-selectin glycoprotein ligand-1 (PSGL-1); the majority of tumor-infiltrating leukocytes express PSGL-1, causing T cell and immune inhibition via PSGL-1 mediator molecules. We aimed to investigate the effect of variable number of tandem repeat (VNTR) polymorphism in the second exon of the PSGL-1 gene on MM susceptibility, response to treatment and survival in our patient group. A total of 238 patients diagnosed with MM between January 2010 and January 2021 and 162 healthy individuals as a control group were included in this cross-sectional study. The genotypes of the VNTR polymorphism in the second exon of the PSGL-1 gene were statistically compared between patients and healthy controls; the statistically significant effects of the genotypes on response to first-line treatment and survival were examined. The AC genotype was significantly higher in healthy controls compared to patients diagnosed with MM (p < 0.001). The median PFS in patients with AA/AB/AC was 56 months, while it was 100 months in patients with BB/CC. The hazard ratio of 1.34 for PFS was found to be clinically significant and having the BB/CC genotype could provide a longer PFS compared to others, but it was not statistically significant due to the sample size. Our study results will shed light on new study plans in terms of immune checkpoint target therapies among conventional treatment preferences in MM.

Treatment advances in high-grade gliomas

High-grade gliomas (HGG) pose significant challenges in modern tumour therapy due to the distinct biological properties and limitations of the blood-brain barrier. This review discusses recent advancements in HGG treatment, particularly in the context of immunotherapy and cellular therapy. Initially, treatment strategies focus on targeting tumour cells guided by the molecular characteristics of various gliomas, encompassing chemotherapy, radiotherapy and targeted therapy for enhanced precision. Additionally, technological enhancements are augmenting traditional treatment modalities. Furthermore, immunotherapy, emphasising comprehensive tumour management, has gained widespread attention. Immune checkpoint inhibitors, vaccines and CAR-T cells exhibit promising efficacy against recurrent HGG. Moreover, emerging therapies such as tumour treating fields (TTFields) offer additional treatment avenues for patients with HGG. The combination of diverse treatments holds promise for improving the prognosis of HGG, particularly in cases of recurrence.

Reviewing the significance of dendritic cell vaccines in interrupting breast cancer development

Breast cancer is a heterogeneous disease and is the most prevalent cancer in women. According to the U.S breast cancer statistics, about 1 in every 8 women develop an invasive form of breast cancer during their lifetime. Immunotherapy has been a significant advancement in the treatment of cancer with multiple studies reporting favourable patient outcomes by modulating the immune response to cancer cells. Here, we review the significance of dendritic cell vaccines in treating breast cancer patients. We discuss the involvement of dendritic cells and oncodrivers in breast tumorigenesis, highlighting the rationale for targeting oncodrivers and neoantigens using dendritic cell vaccine therapy. We review different dendritic cell subsets and maturation states previously used to develop vaccines and suggest the use of DC vaccines for breast cancer prevention. Further, we highlight that the intratumoral delivery of type 1 dendritic cell vaccines in breast cancer patients activates tumor antigen-specific CD4+ T helper cell type 1 (Th1) cells, promoting an anti-tumorigenic immune response while concurrently blocking pro-tumorigenic responses. In summary, this review provides an overview of the current state of dendritic cell vaccines in breast cancer highlighting the challenges and considerations necessary for an efficient dendritic cell vaccine design in interrupting breast cancer development.

Immune checkpoint blockade in hematological malignancies: current state and future potential

Malignant cells are known to evade immune surveillance by engaging immune checkpoints which are negative regulators of the immune system. By restoring the T-lymphocyte mediated anti-tumor effect, immune checkpoint inhibitors (ICI) have revolutionized the treatment of solid tumors but have met rather modest success in hematological malignancies. Currently, the only FDA approved indications for ICI therapy are in classic hodgkin lymphoma and primary mediastinal B cell lymphoma. Multiple clinical trials have assessed ICI therapy alone and in combination with standard of care treatments in other lymphomas, plasma cell neoplasms and myeloid neoplasms but were noted to have limited efficacy. These trials mostly focused on PD-1/PDL-1 and CTLA-4 inhibitors. Recently, there has been an effort to target other T-lymphocyte checkpoints like LAG-3, TIM-3, TIGIT along with improving strategies of PD-1/PDL-1 and CTLA-4 inhibition. Drugs targeting the macrophage checkpoint, CD47, are also being tested. Long term safety and efficacy data from these ongoing studies are eagerly awaited. In this comprehensive review, we discuss the mechanism of immune checkpoint inhibitors, the key takeaways from the reported results of completed and ongoing studies of these therapies in the context of hematological malignancies.

Application of Engineered Dendritic Cell Vaccines in Cancer Immunotherapy: Challenges and Opportunities

OPINION STATEMENT

The primary objective of this study is to evaluate the effectiveness of cancer vaccines containing genetically modified dendritic cells (DCs) in inducing transformational immune responses. This paper sheds considerable light on DCs' function in advancing treatment techniques. This objective is achieved by thoroughly analyzing the many facets of DCs and their strategic integration into cancer treatment. Due to their role as immune response regulators, DCs can potentially enhance cancer treatment strategies. DCs have the potential to revolutionize immunotherapy, as shown by a comprehensive analysis of their numerous characteristics. The review deftly transitions from examining the fundamentals of preclinical research to delving into the complexities of clinical implementation while acknowledging the inherent challenges in translating DC vaccine concepts into tangible progress. The analysis also emphasizes the potential synergistic outcomes that can be achieved by combining DC vaccines with established pharmaceuticals, thereby emphasizing the importance of employing a holistic approach to enhance treatment efficacy. Despite the existence of transformative opportunities, advancement is hindered by several obstacles. The exhaustive analysis of technical complexities, regulatory dynamics, and upcoming challenges provides valuable insights for overcoming obstacles requiring strategic navigation to incorporate DC vaccines successfully. This document provides a comprehensive analysis of the developments in DC-based immunotherapy, concentrating on its potential to transform cancer therapy radically.

Immune checkpoint inhibitors for multiple myeloma immunotherapy

Multiple myeloma (MM) is related to immune disorders, recent studys have revealed that immunotherapy can greatly benefit MM patients. Immune checkpoints can negatively modulate the immune system and are closely associated with immune escape. Immune checkpoint-related therapy has attracted much attention and research in MM. However, the efficacy of those therapies need further improvements. There need more thoughts about the immune checkpoint to translate their use in clinical work. In our review, we aggregated the currently known immune checkpoints and their corresponding ligands, further more we propose various ways of potential translation applying treatment based on immune checkpoints for MM patients.

Tumor Vaccines: Unleashing the Power of the Immune System to Fight Cancer

This comprehensive review delves into the rapidly evolving arena of cancer vaccines. Initially, we examine the intricate constitution of the tumor microenvironment (TME), a dynamic factor that significantly influences tumor heterogeneity. Current research trends focusing on harnessing the TME for effective tumor vaccine treatments are also discussed. We then provide a detailed overview of the current state of research concerning tumor immunity and the mechanisms of tumor vaccines, describing the complex immunological processes involved. Furthermore, we conduct an exhaustive analysis of the contemporary research landscape of tumor vaccines, with a particular focus on peptide vaccines, DNA/RNA-based vaccines, viral-vector-based vaccines, dendritic-cell-based vaccines, and whole-cell-based vaccines. We analyze and summarize these categories of tumor vaccines, highlighting their individual advantages, limitations, and the factors influencing their effectiveness. In our survey of each category, we summarize commonly used tumor vaccines, aiming to provide readers with a more comprehensive understanding of the current state of tumor vaccine research. We then delve into an innovative strategy combining cancer vaccines with other therapies. By studying the effects of combining tumor vaccines with immune checkpoint inhibitors, radiotherapy, chemotherapy, targeted therapy, and oncolytic virotherapy, we establish that this approach can enhance overall treatment efficacy and offset the limitations of single-treatment approaches, offering patients more effective treatment options. Following this, we undertake a meticulous analysis of the entire process of personalized cancer vaccines, elucidating the intricate process from design, through research and production, to clinical application, thus helping readers gain a thorough understanding of its complexities. In conclusion, our exploration of tumor vaccines in this review aims to highlight their promising potential in cancer treatment. As research in this field continues to evolve, it undeniably holds immense promise for improving cancer patient outcomes.

Elevated programmed cell death-1 protein/ligand (PD-1/PD-L1) and variants are associated with susceptibility to multiple myeloma: a case-control study in the Chinese cohort

Multiple myeloma (MM) is a malignant disorder characterised by progressive immune dysregulation. The importance of programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) in MM has been documented in various populations, but studies have been limited to the Chinese cohort. In the present study, we examined the role of PD-1/PDL-1 in large cohorts of Chinese patients with MM and healthy controls to reveal a possible association with MM. Three hundred thirty-four MM patients and 202 healthy age-sex-matched subjects were enrolled in the present study. Serum levels of PD-1 and PD-L1 were quantified by ELISA. Percentages of T cells (CD4+ and CD8+ T cells) expressing PD-1 receptor were assessed by flow cytometry. Variants in PD-L1 (rs4143815) and PD-1 gene (rs2227981, rs2227982, rs7421861 and rs11568821) were genotyped by PCR-RFLP method. Patients with multiple myeloma had higher levels of PD-1 and PDL-1 than healthy controls, indicating an important role for programmed cell death protein-1 and its ligand in the pathogenesis of MM. T cells expressing PD-1 receptors were also significantly higher in MM patients than in controls. Mutants for PD-L1 (rs4143815) and PD-1 (rs2227982 and rs7421861) polymorphisms were significantly more common in MM than in HC. Interestingly, PD-L1 (rs4143815) and PD-1 (rs2227982 and rs7421861) variants were linked to higher sPD-L1 and sPD-1 levels, respectively. PD-1/PD-L1 levels are significantly higher in MM patients and could be a promising biomarker for the disease. Variants of PD-L1 and PD-1 are linked to serum-soluble proteins and are associated with the development of MM.

Breaking down the tumor immune infiltration within pediatric sarcomas

Immunotherapies are a promising therapeutic option, yet for a variety of reasons, these treatments have achieved limited success against sarcomas. The immunosuppressive tumor microenvironment (TME) of sarcomas as well as lack of predictive biomarkers, decreased T-cell clonal frequency, and high expression of immunosuppressive infiltrating cells has thus far prevented major success using immunotherapies. By breaking down the TME into its individual components and understanding how the various cell types interact with each other as well as in the context of the complex immune microenvironment, can lead to effective therapeutic immunotherapy treatments, potentially improving outcomes for those with metastatic disease.

Therapeutic strategies to enhance immune response induced by multiple myeloma cells

Multiple myeloma (MM)as a haematological malignancy is still incurable. In addition to the presence of somatic genetic mutations in myeloma patients, the presence of immunosuppressive microenvironment greatly affects the outcome of treatment. Although the discovery of immunotherapy makes it possible to break the risk of high toxicity and side effects of traditional chemotherapeutic drugs, there are still obstacles of ineffective treatment or disease recurrence. In this review, we discuss therapeutic strategies to further enhance the specific anti-tumor immune response by activating the immunogenicity of MM cells themselves. New ideas for future myeloma therapeutic approaches are provided.

Immune dysregulation in multiple myeloma: the current and future role of cell-based immunotherapy

Immune dysregulation is a hallmark of clinically active multiple myeloma (MM). Interactions between malignant clonal cells and immune cells within the bone marrow microenvironment are associated with the formation of a milieu favorable to tumor progression. IL-10, TGF-β and other immunoregulatory pathways are upregulated, promoting angiogenesis, tumor cell survival and inhibition of the native immune response. Transcriptomic evaluation of the bone marrow microenvironment reveals polarization of the T cell repertoire towards exhaustion and predominance of accessory cells with immunosuppressive qualities. These changes facilitate the immune escape of tumor cells and functional deficiencies that manifest as an increased risk of infection and a reduction in response to vaccinations. Immunotherapy with Chimeric Antigen Receptor (CAR) T cells and other cellular-based approaches have transformed outcomes for patients with advanced MM. Characterization of the immune milieu and identification of biomarkers predictive of treatment response are essential to increasing durability and allowing for the incorporation of novel strategies such as cancer vaccines. This paper will review the current use of cancer vaccines and CAR T cell therapy in MM as well as potential opportunities to expand and improve the application of these platforms.

Cobimetinib Alone and Plus Venetoclax With/Without Atezolizumab in Patients With Relapsed/Refractory Multiple Myeloma

INTRODUCTION

Mitogen-activated protein kinase pathway mutations are present in >50% of patients with relapsed/refractory (R/R) multiple myeloma (MM). MEK inhibitors show limited single-agent activity in R/R MM; combination with B-cell lymphoma-2 (BCL-2) and programmed death-ligand 1 inhibition may improve efficacy. This phase Ib/II trial (NCT03312530) evaluated safety and efficacy of cobimetinib (cobi) alone and in combination with venetoclax (ven) with/without atezolizumab (atezo) in patients with R/R MM.

PATIENTS AND METHODS

Forty-nine patients were randomized 1:2:2 to cobi 60 mg/day on days 1-21 (n = 6), cobi 40 mg/day on days 1-21 + ven 800 mg/day on days 1-28 with/without atezo 840 mg on days 1 and 15 of 28-day cycles (cobi-ven, n = 22; cobi-ven-atezo, n = 21). Safety run-in cohorts evaluated cobi-ven and cobi-ven-atezo dose levels.

RESULTS

Any-grade common adverse events (AEs) with cobi, cobi-ven, and cobi-ven-atezo, respectively, included diarrhea (33.3%, 81.8%, 90.5%) and nausea (16.7%, 50.0%, 66.7%); common grade ≥3 AEs included anemia (0%, 22.7%, 23.8%), neutropenia (0%, 13.6%, 38.1%), and thrombocytopenia (0%, 18.2%, 23.8%). The overall response rate for all-comers was 0% (cobi), 27.3% (cobi-ven), and 28.6% (cobi-ven-atezo), and 0%, 50.0%, and 100%, respectively, in patients with t(11;14)+. Biomarker analysis demonstrated non-t(11;14) patient selection with NRAS/KRAS/BRAF mutation or high BCL-2/BCL-2-L1 ratio (>52% of the study population) could enrich for responders to the cobi-ven combination.

CONCLUSIONS

Cobi-ven and cobi-ven-atezo demonstrated manageable safety with moderate activity in all-comers, and higher activity in patients with t(11;14)+ MM, supporting a biomarker-driven approach for ven in MM.

Enhanced anti-tumor immunity of vaccine combined with anti-PD-1 antibody in a murine bladder cancer model

PURPOSE

Programmed cell death protein 1 (PD-1) and ligand programmed death ligand 1 (PD-L1) are important immune-suppressive regulators in the tumor microenvironment. A vaccine-induced immune effect on tumor cells is blunted by the immunosuppressive tumor microenvironment. Therefore, we hypothesized that a dendritic cell (DC) vaccine combined with anti-PD-1 (αPD-1) antibodies could elicit a synergistic anti-tumor immunity in bladder cancer.

MATERIALS AND METHODS

We produced a model of subcutaneous transplantation in C3H/HeJ mice by transplanting murine MBT-2 bladder cancer cells. DCs were isolated from normal C3H/HeJ mice, followed by stimulation against MBT-2 lysate before injection. Two weeks later of MBT-2 inoculation, αPD-1 and stimulated DCs were injected two times at one-week interval intraperitoneally and intravenously, respectively. Tumor-infiltrating immune cells and splenocytes were analyzed using flow cytometry. T-cell-mediated anti-tumor responses were measured by interferon (IFN)-γ ELISPOT and lactate dehydrogenase assays.

RESULTS

The mice treated with DC+αPD-1 showed a significant decrease in tumor volume compared to the DC-treated mice and IgG-treated group. Survival of the DC+αPD-1-treated group was improved compared with that of the IgG-treated mice. IFN-γ secretion from splenocytes against tumor cells was significantly increased in the DC+αPD-1 group compared with that of αPD-1-treated mice. The frequency of CD8⁺ and CD4⁺ T-cells in spleens was statistically increased in the DC+αPD-1-treated mice compared to those receiving monotherapy (DC- or αPD-1-treated group).

CONCLUSIONS

Our results support the hypothesis that the combination therapy of a DC vaccine and αPD-1 antibodies could enhance the anti-tumor immune response against bladder cancer.

Characteristics and postoperative dynamic changes in circulating CD4+ helper T lymphocytes in patients with breast cancer

Introduction

Circulating CD4⁺ helper T cell (Th) subsets provide potentially important information on disease progression in several cancers. In this study, we explored the characteristics and postoperative dynamic changes in circulating CD4⁺Th subsets in patients with breast cancer.

Methods

Circulating CD4⁺Th subsets, including CD4⁺ naive T cells (Tn), CD4⁺ central memory T cells (Tcm), CD4⁺ effector memory T cells (Tem), CD4⁺CD57⁺T, and CD4⁺PD-1⁺T, were detected with multiparameter flow cytometry. T-test and Wilcoxon rank-sum test were used to compare differences between groups for normally and non-normally distributed continuous variables, respectively. Postoperative dynamic changes in CD4⁺Th subsets were assessed using the paired-sample rank-sum test.

Results

Seventy-five patients with invasive breast cancer and fifty-three patients with benign breast tumors were enrolled. Compared with that in patients with benign tumors, the proportion of CD4⁺Tn in patients with breast cancer patients decreased, whereas the proportion and absolute number of CD4⁺CD57⁺T and CD4⁺PD-1⁺T increased. Moreover, the proportion of CD4⁺PD-1⁺T was correlated with the clinicopathology of breast cancer. After tumor resection, the proportion and absolute number of CD4⁺Tcm significantly decreased, while those of CD4⁺Tem significantly increased, compared with preoperative values. Tumor resection caused significant changes in the proportion and absolute number of CD4⁺CD57⁺T and CD4⁺PD-1⁺ T, both of which showed significant decreases.

Discussion

We found significant changes in circulating CD4⁺Th subsets in patients with breast cancer. Additionally, complete tumor resection can benefit the patient as it balances the patient's immunosuppression and immune stress and improves the immune exhaustion and immunosenescence states.

Targeting the MDM2-p53 pathway in dedifferentiated liposarcoma

Dedifferentiated liposarcoma (DDLPS) is an aggressive adipogenic cancer with poor prognosis. DDLPS tumors are only modestly sensitive to chemotherapy and radiation, and there is a need for more effective therapies. Genetically, DDLPS is characterized by a low tumor mutational burden and frequent chromosomal structural abnormalities including amplification of the 12q13-15 chromosomal region and the MDM2 gene, which are defining features of DDLPS. The MDM2 protein is an E3 ubiquitin ligase that targets the tumor suppressor, p53, for proteasomal degradation. MDM2 amplification or overexpression in human malignancies is associated with cell-cycle progression and worse prognosis. The MDM2-p53 interaction has thus garnered interest as a therapeutic target for DDLPS and other malignancies. MDM2 binds p53 via a hydrophobic protein interaction that is easily accessible with synthetic analogues. Multiple agents have been developed, including Nutlins such as RG7112 and small molecular inhibitors including SAR405838 and HDM201. Preclinical in vitro and animal models have shown promising results with MDM2 inhibition, resulting in robust p53 reactivation and cancer cell death. However, multiple early-phase clinical trials have failed to show a benefit with MDM2 pathway inhibition for DDLPS. Mechanisms of resistance are being elucidated, and novel inhibitors and combination therapies are currently under investigation. This review provides an overview of these strategies for targeting MDM2 in DDLPS.

The depths of PD-1 function within the tumor microenvironment beyond CD8+ T cells

Programmed cell death-1 (PD-1; CD279) is a cell surface receptor that is expressed in both innate and adaptive immune cells. The role of PD-1 in adaptive immune cells, specifically in CD8+ T cells, has been thoroughly investigated but its significance in other immune cells is yet to be well established. This review will address the role of PD-1 based therapies in enhancing non-CD8+ T cell immune responses within cancer. Specifically, the expression and function of PD-1 in non-CD8+ immune cell compartments such as CD4+ T helper cell subsets, myeloid cells and innate lymphoid cells (ILCs) will be discussed. By understanding the immune cell specific function of PD-1 within tissue resident innate and adaptive immune cells, it will be possible to stratify patients for PD-1 based therapies for both immunogeneic and non-immunogeneic neoplastic disorders. With this knowledge from fundamental and translational studies, PD-1 based therapies can be utilized to enhance T cell independent immune responses in cancers.

Immunotherapy for the treatment of multiple myeloma

Despite advances in treatment for multiple myeloma, the majority of patients ultimately develop relapsed disease marked by immune evasion and resistance to standard therapy. Immunotherapy has emerged as a powerful tool for tumor-directed cytotoxicity with the unique potential to induce immune memory to reduce the risk of relapse. Understanding the specific mechanisms of immune dysregulation and dysfunction in advanced myeloma is critical to the development of further therapies that produce a durable response. Adoptive cellular therapy, most strikingly CAR T cell therapy, has demonstrated dramatic responses in the setting of refractory disease. Understanding the factors that contribute to immune evasion and the mechanisms of response and resistance to therapy will be critical to developing the next generation of adoptive cellular therapies, informing novel combination therapy, and determining the optimal time to incorporate immune therapy in the treatment of myeloma.

Multiple Myeloma-Derived Extracellular Vesicles Modulate the Bone Marrow Immune Microenvironment

Multiple myeloma (MM), the third most frequent hematological cancer worldwide, is characterized by the proliferation of neoplastic plasma cells in the bone marrow (BM). One of the hallmarks of MM is a permissive BM microenvironment. Increasing evidence suggests that cell-to-cell communication between myeloma and immune cells via tumor cell-derived extracellular vesicles (EV) plays a key role in the pathogenesis of MM. Hence, we aimed to explore BM immune alterations induced by MM-derived EV. For this, we inoculated immunocompetent BALB/cByJ mice with a myeloma cell line, MOPC315.BM, inducing a MM phenotype. Upon tumor establishment, characterization of the BM microenvironment revealed the expression of both activation and suppressive markers by lymphocytes, such as granzyme B and PD-1, respectively. In addition, conditioning of the animals with MOPC315.BM-derived EV, before transplantation of the MOPC315.BM tumor cells, did not anticipate the disease phenotype. However, it induced features of suppression in the BM milieu, such as an increase in PD-1 expression by CD4+ T cells. Overall, our findings reveal the involvement of MOPC315.BM-derived EV protein content as promoters of immune niche remodeling, strengthening the importance of assessing the mechanisms by which MM may impact the immune microenvironment.

Current State of Cell Therapies for Breast Cancer

Metastatic breast cancer (BC) is an aggressive form of cancer and is an absolute challenge to treat. This review discusses the standard treatments available for metastatic BC. It further highlights the rationale for targeting oncodrivers, tumor-associated antigens, and neoantigens in BC. Explaining the significance of immune response in successful immunotherapeutic studies, it draws attention towards how adoptive cell therapy can be a useful immunotherapeutic tool. We focus on adoptive cell therapy in BC covering tumor-infiltrating lymphocyte therapy, engineered T cell receptor therapy, chimeric antigen receptor therapy, dendritic cell therapy and natural killer cell therapy. In this work, we aim to provide an overview of clinical data regarding the use of cellular immunotherapies in BC. Eventually, we conclude by proposing future adoptive cell therapy approaches, which can be used to cure BC.

Advanced Immune Cell Profiling by Multiparameter Flow Cytometry in Humanized Patient-Derived Tumor Mice

"Humanized" mice have been widely used for the characterization of human cancer progression and as a powerful preclinical model. Standardization of multicolor phenotyping could help to identify immune cell patterns involved in checkpoint-related complications. Therefore, we applied established protocols for immune cell profiling to our humanized Patient-Derived Xenograft (hPDX) model. hPDX are characterized by the co-existence of a human immune system and a patient-derived tumor transplant. These mice possess a human-like immune system after CD34⁺ stem cell transplantation while the reconstitution level of the immune system was not related to the quantity of transplanted CD34⁺ cells. Contamination ≤ 1.2% by CD3⁺ cells in the hematopoietic stem cell (HSC) transplant did not trigger abnormal T cell maturation. Different B and T cell differentiation stages were identified, as well as regulatory T cells (Tregs) and exhausted T cells that expressed TIGIT, PD-1, or KLRG1. Overall, the application of standardized protocols for the characterization of immune cells using flow cytometry will contribute to a better understanding of immune-oncologic processes.

Programmed Cell Death-1 and Its Ligands as Targets for Therapy of Multiple Myeloma Patients

Purpose

Among hematological malignancies, the expression profile of programmed cell death-1 (PD-1) and its ligands in multiple myeloma (MM) is still debated by numerous research groups. In current study, we characterized the expression of PD-1 and its ligands both on RNA and protein levels in MM patients. We have also attempted to analyze whether daratumumab therapy might overcome CD38-mediated immunosuppression that inhibits in particular CD8+ T-cell function.

Patients and Methods

This study included 149 newly diagnosed MM patients and 15 relapsed/refractory MM patients before and after daratumumab treatment. The mRNA levels of PDCD1, PDCD1LG1, PDCD1LG2 and their splicing variants was assessed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Flow cytometry was used to characterize the surface expression of PD-1 and its ligands on plasma cells, B and T cells. The surface expression of PD-1 on T cells was assessed by flow cytometry before and after daratumumab treatment.

Results

The mRNA expression of PDCD1LG1, PDCD1LG2 and their splicing variants were higher in plasma cells as compared to bone marrow mononuclear cells (BMMCs). Our results show that the percentage of plasma cells expressing PD-L1 was significantly higher than plasma cells expressing PD-L2 (p<0.0001) in bone marrow (BM) of MM patients. There was no significant difference between the percentage of plasma cells expressing PD-1 and B cells expressing PD-1 in BM of MM patients (11.19% vs 8.91%). We also found that the percentage of CD8+PD-1+ T cells was significantly higher than CD4+PD-1+T cells in BM (p<0.0001) of MM patients. Here, we observed no change in PD-1 expression on CD4+ and CD8+ T cells after the daratumumab treatment.

Conclusion

The PD-1 and its ligands might represent an interesting target for MM immunotherapy, as one would target both malignant plasma cells as well as the immune cells that play a key role in tumor escape mechanisms.

Dendritic Cell-Based Immunotherapy in Multiple Myeloma: Challenges, Opportunities, and Future Directions

Immunotherapeutic approaches, including adoptive cell therapy, revolutionized treatment in multiple myeloma (MM). As dendritic cells (DCs) are professional antigen-presenting cells and key initiators of tumor-specific immune responses, DC-based immunotherapy represents an attractive therapeutic approach in cancer. The past years, various DC-based approaches, using particularly ex-vivo-generated monocyte-derived DCs, have been tested in preclinical and clinical MM studies. However, long-term and durable responses in MM patients were limited, potentially attributed to the source of monocyte-derived DCs and the immunosuppressive bone marrow microenvironment. In this review, we briefly summarize the DC development in the bone marrow niche and the phenotypical and functional characteristics of the major DC subsets. We address the known DC deficiencies in MM and give an overview of the DC-based vaccination protocols that were tested in MM patients. Lastly, we also provide strategies to improve the efficacy of DC vaccines using new, improved DC-based approaches and combination therapies for MM patients.

Simultaneous silencing of the A2aR and PD-1 immune checkpoints by siRNA-loaded nanoparticles enhances the immunotherapeutic potential of dendritic cell vaccine in tumor experimental models

Following various immunotherapies, lack of proper anti-tumor immune responses is considered a significant problem in novel cancer therapeutic approaches. The expression of inhibitory checkpoint molecules on tumor-infiltrating T cells is one of the main reasons for the ineffectiveness of various immunotherapies. Therefore, we decided to inhibit two of the most important immune checkpoints expressed on tumor-associated T cells, PD-1 and A2aR. Ligation of PD-1 with PD-L1 and A2aR with adenosine significantly suppress T cell responses against tumor cells. Whitin tumors, specific inhibition of these molecules on T cells is of particular importance for successful immunotherapy as well as the elimination of treatment-associated side-effects. Thus, in this study, superparamagnetic iron oxide (SPION) nanoparticles (NPs) were covered by chitosan lactate (CL), functionalized with TAT peptide, and loaded with siRNA molecules against PD-1 and A2aR. Appropriate physicochemical properties of the prepared NPs resulted in efficient delivery of siRNA to tumor-derived T cells and suppressed the expression of A2aR and PD-1, ex vivo. T cell functions such as cytokine secretion and proliferation were considerably enhanced by the downregulation of these molecules which led to an increase in their survival time. Interestingly, treatment of CT26 and 4T1 mouse tumors with siRNA-loaded NPs not only inhibited tumor growth but also markedly increased anti-tumor immune responses and survival time. The results strongly support the efficacy of SPION-CL-TAT NPs loaded with anti-PD-1/A2aR siRNAs in cancer therapy and their further development for cancer patients in the near future.

Intercepting Premalignant, Preinvasive Breast Lesions Through Vaccination

Breast cancer (BC) prevention remains the ultimate cost-effective method to reduce the global burden of invasive breast cancer (IBC). To date, surgery and chemoprevention remain the main risk-reducing modalities for those with hereditary cancer syndromes, as well as high-risk non-hereditary breast lesions such as ADH, ALH, or LCIS. Ductal carcinoma in situ (DCIS) is a preinvasive malignant lesion of the breast that closely mirrors IBC and, if left untreated, develops into IBC in up to 50% of lesions. Certain high-risk patients with DCIS may have a 25% risk of developing recurrent DCIS or IBC, even after surgical resection. The development of breast cancer elicits a strong immune response, which brings to prominence the numerous advantages associated with immune-based cancer prevention over drug-based chemoprevention, supported by the success of dendritic cell vaccines targeting HER2-expressing BC. Vaccination against BC to prevent or interrupt the process of BC development remains elusive but is a viable option. Vaccination to intercept preinvasive or premalignant breast conditions may be possible by interrupting the expression pattern of various oncodrivers. Growth factors may also function as potential immune targets to prevent breast cancer progression. Furthermore, neoantigens also serve as effective targets for interception by virtue of strong immunogenicity. It is noteworthy that the immune response also needs to be strong enough to result in target lesion elimination to avoid immunoediting as it may occur in IBC arising from DCIS. Overall, if the issue of vaccine targets can be solved by interrupting premalignant lesions, there is a potential to prevent the development of IBC.

The importance of immune checkpoints in immune monitoring: A future paradigm shift in the treatment of cancer

The growth and development of cancer are directly correlated to the suppression of the immune system. A major breakthrough in cancer immunotherapy depends on various mechanisms to detect immunosuppressive factors that inhibit anti-tumor immune responses. Immune checkpoints are expressed on many immune cells such as T-cells, regulatory B cells (Bregs), dendritic cells (DCs), natural killer cells (NKs), regulatory T (Tregs), M2-type macrophages, and myeloid-derived suppressor cells (MDSCs). Immune inhibitory molecules, including CTLA-4, TIM-3, TIGIT, PD-1, and LAG-3, normally inhibit immune responses via negatively regulating immune cell signaling pathways to prevent immune injury. However, the up-regulation of inhibitory immune checkpoints during tumor progression on immune cells suppresses anti-tumor immune responses and promotes immune escape in cancer. It has recently been indicated that cancer cells can up-regulate various pathways of the immune checkpoints. Therefore, targeting immune inhibitory molecules through antibodies or miRNAs is a promising therapeutic strategy and shows favorable results. Immune checkpoint inhibitors (ICIs) are introduced as a new immunotherapy strategy that enhance immune cell-induced antitumor responses in many patients. In this review, we highlighted the function of each immune checkpoint on different immune cells and therapeutic strategies aimed at using monoclonal antibodies and miRNAs against inhibitory receptors. We also discussed current challenges and future strategies for maximizing these FDA-approved immunosuppressants' effectiveness and clinical success in cancer treatment.

Cellular signaling pathways of T cells in giant cell arteritis

Giant cell arteritis (GCA) is a commonly occurring large vacuities characterized by angiopathy of medium and large-sized vessels. GCA granulomatous formation plays an important role in the pathogenesis of GCA. Analysis of T cell lineages and signaling pathways in GCA have revealed the essential role of T cells in the pathology of GCA. T cells are the dominant population present in GCA lesions. CD4+ T cell subtypes that are present include Th1, Th2, Th9, Th17, follicular helper T (Tfh) cells, and regulatory T (Treg) cells. CD8 T cells can primarily differentiate into cytotoxic CD8+ T lymphocytes and Treg cells. The instrumental part of GCA is the interplay between dendritic cells, macrophages and endothelial cells, which can result in the vascular injury and the characteristics granulomatous infiltrates formation. During the inflammatory loop of GCA, several signaling pathways have been reported to play an essential role in recruiting, activating and differentiating T cells, including T-cell receptor (TCR) signaling, vascular endothelial growth factor (VEGF)-Jagged-Notch signaling and the Janus kinase and signal transducer and activator of transcription (STAT) pathway (JAK-STAT) pathway. In this review, we have focused on the role of T cells and their potential signaling mechanism (s) that are involved in the pathogenesis of GCA. A better understanding of the role of T cells mediated complicated orchestration during the homeostasis and the changes could possibly favor developments of novel treatment strategies against immunological disorders associated with GCA.

Deregulated Expression of Immune Checkpoints on Circulating CD4 T Cells May Complicate Clinical Outcome and Response to Treatment with Checkpoint Inhibitors in Multiple Myeloma Patients

Unlike solid-tumor patients, a disappointingly small subset of multiple myeloma (MM) patients treated with checkpoint inhibitors derive clinical benefits, suggesting differential participation of inhibitory receptors involved in the development of T-cell-mediated immunosuppression. In fact, T cells in MM patients have recently been shown to display features of immunosenescence and exhaustion involved in immune response inhibition. Therefore, we aimed to identify the dominant inhibitory pathway in MM patients to achieve its effective control by therapeutic interventions. By flow cytometry, we examined peripheral blood (PB) CD4 T cell characteristics assigned to senescence or exhaustion, considering PD-1, CTLA-4, and BTLA checkpoint expression, as well as secretory effector function, i.e., capacity for IFN-γ and IL-17 secretion. Analyses were performed in a total of 40 active myeloma patients (newly diagnosed and treated) and 20 healthy controls. At the single-cell level, we found a loss of studied checkpoints’ expression on MM CD4 T cells (both effector (Teff) and regulatory (Treg) cells) primarily at diagnosis; the checkpoint deficit in MM relapse was not significant. Nonetheless, PD-1 was the only checkpoint distributed on an increased proportion of T cells in all MM patients irrespective of disease phase, and its expression on CD4 Teff cells correlated with adverse clinical courses. Among patients, the relative defect in secretory effector function of CD4 T cells was more pronounced at myeloma relapse (as seen in declined Th1/Treg and Th17/Treg cell rates). Although the contribution of PD-1 to MM clinical outcomes is suggestive, our study clearly indicated that the inappropriate expression of immune checkpoints (associated with dysfunctionality of CD4 T cells and disease clinical phase) might be responsible for the sub-optimal clinical response to therapeutic checkpoint inhibitors in MM.

Immunomodulation by durvalumab and pomalidomide in patients with relapsed/refractory multiple myeloma

This study sought to understand how the programmed death ligand 1 (PD-L1) inhibitor durvalumab and the immunomodulatory agent pomalidomide regulate immune cell activation and function in patients with relapsed/refractory (RR) multiple myeloma (MM). Immunologic changes in peripheral blood and bone marrow of patients treated with durvalumab as monotherapy or in combination with pomalidomide with/without dexamethasone were characterized by assessing subsets of immune cells and gene signatures to understand the immunomodulatory effect of the treatment. Soluble PD-L1 levels were elevated at screening in patients with RRMM but did not correlate with response to durvalumab combination therapy. Immune cell subsets were increased in peripheral blood during treatment with durvalumab and pomalidomide, and combination therapy induced significant gene expression changes in the MM tumor microenvironment versus durvalumab alone. Estimation of cell populations based on RNA sequencing data revealed increased monocytes, neutrophils, and natural killer cells with the combination therapy, but not with durvalumab alone. Additionally, multiplex immunofluorescence of bone marrow demonstrated that immune populations were different in responders versus nonresponders to durvalumab plus pomalidomide with dexamethasone therapy. Overall, durvalumab effectively blocked soluble PD-L1; however, durvalumab monotherapy was not associated with immunologic changes, which were observed with combination therapy.

Immune checkpoint inhibitors for the treatment of myeloma: novel investigational options

INTRODUCTION

Multiple myeloma (MM) is still considered incurable and the outcome of patients with triple-class refractory remains very poor. Immunotherapy is considered as a standard of care for the treatment of MM. Among immunotherapeutic approaches, the PD-1/PD-L1 axis is an attractive target because PD-L1 is highly expressed in most myeloma plasma cells. While many types of cancer benefit from checkpoint inhibitor treatment, their relevance in multiple myeloma needs to be defined.

AREAS COVERED

The authors evaluate the published data regarding the mechanism of action, safety profile, and clinical efficacy of the immune checkpoint inhibitors (ICI) for the treatment of multiple myeloma.

EXPERT OPINION

The use of ICI monotherapy does not offer any clinical benefit in myeloma patients. In combination with immunomodulatory drugs (IMID), ICI failed to demonstrate clinical benefit and were associated with increased toxicity. Given the toxicities of these treatments, predictive markers would be useful to select patients who would benefit most. Clinical studies are necessary to evaluate the safety and efficacy of checkpoint inhibitors in combination with other standards of care such as proteasome inhibitors and monoclonal antibodies. The combination of anti-PD-1 with T-cell engager (TCE) or CAR-T cells seems theoretically attractive and should be explored in clinical trials.

Mechanisms of Action of the New Antibodies in Use in Multiple Myeloma

Monoclonal antibodies (mAbs) directed against antigen-specific of multiple myeloma (MM) cells have Fc-dependent immune effector mechanisms, such as complement-dependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC), and antibody-dependent cellular phagocytosis (ADCP), but the choice of the antigen is crucial for the development of effective immuno-therapy in MM. Recently new immunotherapeutic options in MM patients have been developed against different myeloma-related antigens as drug conjugate-antibody, bispecific T-cell engagers (BiTEs) and chimeric antigen receptor (CAR)-T cells. In this review, we will highlight the mechanism of action of immuno-therapy currently available in clinical practice to target CD38, SLAMF7, and BCMA, focusing on the biological role of the targets and on mechanisms of actions of the different immunotherapeutic approaches underlying their advantages and disadvantages with critical review of the literature data.

Curcumin in Osteosarcoma Therapy: Combining With Immunotherapy, Chemotherapeutics, Bone Tissue Engineering Materials and Potential Synergism With Photodynamic Therapy

Osteosarcoma is a dominating malignant bone tumor with high mortality due to pulmonary metastases. Furthermore, because of the cancer cell erosion and surgery resection, osteosarcoma always causes bone defects, which means dysfunction and disfigurement are seldom inevitable. Although various advanced treatments (e.g. chemotherapy, immunotherapy, radiotherapy) are coming up, the 5-year survival rate for osteosarcoma with metastases is still dismal. In line with this, the more potent treatments for osteosarcoma are in high demand. Curcumin, a perennial herb, has been reportedly applied in the therapy of various types of tumors via different mechanisms. In vitro, it has also been reported that curcumin can inhibit the proliferation of osteosarcoma cell lines and can be used to repair bone defects. This seems curcumin is a promising candidate in osteosarcoma treatment. However, due to its congenital property like hydrophobicity, and low bioavailability, affecting its anticancer effect, clinical applications of curcumin are highly limited. To enhance its performance in cancer therapies, some synergist approaches with curcumin have emerged. The present review presents some prospective ones (i.e. combinations with immunotherapy, chemotherapeutics, bone tissue engineering, and biomaterials) applied in osteosarcoma treatment. Additionally, with the advancements of photodynamic therapy in cancer therapy, this review also prospects the combination of curcumin with photodynamic therapy in osteosarcoma treatment.

Efficacy and Safety of Durvalumab Combined with Daratumumab in Daratumumab-Refractory Multiple Myeloma Patients

Simple Summary

The CD38-targeting antibody daratumumab has marked activity in multiple myeloma through direct anti-tumor effects and immunomodulatory activity. However, eventually most patients will develop daratumumab-refractory disease. We hypothesized that daratumumab-resistance could be reversed by the addition of an inhibitor of the PD-1/PD-L1 signaling pathway, resulting in improved T- and NK-cell mediated anti-tumor immune responses. We therefore performed a phase 2 study to investigate the efficacy and safety of adding the PD-L1 checkpoint inhibitor durvalumab to daratumumab at the time of daratumumab failure. The toxicity profile of the daratumumab/durvalumab combination was acceptable, but none of the 18 enrolled patients achieved a clinical response. Immunomonitoring of bone marrow samples at baseline and during treatment showed a reduction of regulatory T-cell numbers and a decrease in the proportion of T-cells expressing LAG3 and CD8⁺ T-cells expressing TIM-3, whereas tumor cell characteristics were not affected. These results indicate that co-targeting PD-L1 at the time of daratumumab failure is insufficient to reverse daratumumab-resistance.

Abstract

Daratumumab is active both as a single agent and in combination with other agents in multiple myeloma (MM) patients. However, the majority of patients will develop daratumumab-refractory disease, which carries a poor prognosis. Since daratumumab also has immunomodulatory effects, addition of the PD-L1 blocking antibody durvalumab at the time of progression may reverse daratumumab-resistance. The efficacy and safety of daratumumab and durvalumab in daratumumab-refractory relapsed/refractory MM patients was evaluated in this prospective, single-arm phase 2 study (NCT03000452). None of the 18 enrolled patients achieved PR or better. The frequency of serious adverse events was 38.9%, with one patient experiencing an immune related adverse event (grade 2 hyperthyroidism). No infusion-related reactions were observed. Analysis of tumor- and immune cell characteristics was performed on bone marrow samples obtained at baseline and during treatment. Daratumumab combined with durvalumab reduced the frequency of regulatory T-cells and decreased the proportion of T-cells expressing LAG3 and CD8⁺ T-cells expressing TIM-3, without altering T- and NK-cell frequencies. Durvalumab did not affect tumor cell characteristics associated with daratumumab resistance. In conclusion, the addition of durvalumab to daratumumab following development of daratumumab-resistance was associated with an acceptable toxicity profile, but was not effective. This indicates that inhibition of the PD-1/PD-L1 signaling pathway at the time of daratumumab-resistance is insufficient to reverse daratumumab-resistance.

Bone marrow-derived mesenchymal stem cells inhibit CD8+ T cell immune responses via PD-1/PD-L1 pathway in multiple myeloma

High expression of the inhibitory receptor programmed cell death ligand 1 (PD-L1) on tumor cells and tumor stromal cells have been found to play a key role in tumor immune evasion in several human malignancies. However, the expression of PD-L1 on bone marrow mesenchymal stem cells (BMSCs) and whether the programmed cell death 1 (PD-1)/PD-L1 signal pathway is involved in the BMSCs versus T cell immune response in multiple myeloma (MM) remains poorly defined. In this study, we explored the expression of PD-L1 on BMSCs from newly diagnosed MM (NDMM) patients and the role of PD-1/PD-L1 pathway in BMSC-mediated regulation of CD8⁺ T cells. The data showed that the expression of PD-L1 on BMSCs in NDMM patients was significantly increased compared to that in normal controls (NC) (18·81 ± 1·61 versus 2·78± 0·70%; P < 0·001). Furthermore, the PD-1 expression on CD8⁺ T cells with NDMM patients was significantly higher than that in normal controls (43·22 ± 2·98 versus 20·71 ± 1·08%; P < 0·001). However, there was no significant difference in PD-1 expression of CD4⁺ T cells and natural killer (NK) cells between the NDMM and NC groups. Additionally, the co-culture assays revealed that BMSCs significantly suppressed CD8⁺ T cell function. However, the PD-L1 inhibitor effectively reversed BMSC-mediated suppression in CD8⁺ T cells. We also found that the combination of PD-L1 inhibitor and pomalidomide can further enhance the killing effect of CD8⁺ T cells on MM cells. In summary, our findings demonstrated that BMSCs in patients with MM may induce apoptosis of CD8⁺ T cells through the PD-1/PD-L1 axis and inhibit the release of perforin and granzyme B from CD8⁺ T cells to promote the immune escape of MM.

PD-1 Immune Checkpoint Inhibitor Therapy Malignant Tumor Based on Monotherapy and Combined Treatment Research

Recently, immunotherapy has become the fourth pillar of cancer treatment in addition to surgery therapy, chemotherapy, and radiation therapy. The inhibitors of programed cell death protein 1 (PD-1) and its ligand PD-L1 are the new stars in immunotherapy, as they can overcome tumor immunosuppression. However, the efficacy of PD-1 inhibitors still needs to be further developed for clinical treatment. Therefore, research into treatment with anti-PD-1 drugs has emerged as a new development field. This review provides novel insights into the role and mechanism of PD-1 combination anti-tumor therapy, thereby promoting its clinical application in anti-tumor immunotherapy.

Immune System Alterations in Multiple Myeloma: Molecular Mechanisms and Therapeutic Strategies to Reverse Immunosuppression

Simple Summary

A common characteristic of multiple myeloma (MM) is the dysfunction of patients’ immune system, a condition termed immunosuppression. This state is mainly due to alterations in the number and functionality of the principal immune populations. In this setting, immunotherapy has acquired high relevance in the last years and the investigation of agents that boost the immune system represent a field of interest. In the present review, we will summarize the main cellular and molecular alterations observed in MM patients’ immune system. Furthermore, we will describe the mechanisms of action of the four immunotherapeutic drugs approved so far for the treatment of MM, which are part of the group of monoclonal antibodies (mAbs). Finally, the immune-stimulating effects of several therapeutic agents are described due to their potential role in reversing immunosuppression and, therefore, in favoring the efficacy of immunotherapy drugs, such as mAbs, as part of future pharmacological combinations.

Abstract

Immunosuppression is a common feature of multiple myeloma (MM) patients and has been associated with disease evolution from its precursor stages. MM cells promote immunosuppressive effects due to both the secretion of soluble factors, which inhibit the function of immune effector cells, and the recruitment of immunosuppressive populations. Alterations in the expression of surface molecules are also responsible for immunosuppression. In this scenario, immunotherapy, as is the case of immunotherapeutic monoclonal antibodies (mAbs), aims to boost the immune system against tumor cells. In fact, mAbs exert part of their cytotoxic effects through different cellular and soluble immune components and, therefore, patients’ immunosuppressive status could reduce their efficacy. Here, we will expose the alterations observed in symptomatic MM, as compared to its precursor stages and healthy subjects, in the main immune populations, especially the inhibition of effector cells and the activation of immunosuppressive populations. Additionally, we will revise the mechanisms responsible for all these alterations, including the interplay between MM cells and immune cells and the interactions among immune cells themselves. We will also summarize the main mechanisms of action of the four mAbs approved so far for the treatment of MM. Finally, we will discuss the potential immune-stimulating effects of non-immunotherapeutic drugs, which could enhance the efficacy of immunotherapeutic treatments.

Autologous Stem Cell Transplantation for Myeloma: Cytoreduction or an Immunotherapy?

The incidence of multiple myeloma (MM), a bone marrow (BM) resident hematological malignancy, is increasing globally. The disease has substantial morbidity and mortality and remains largely incurable. Clinical studies show that autologous stem cell transplantation (ASCT) remains efficacious in eligible patients, providing a progression free survival (PFS) benefit beyond novel therapies alone. Conventionally, improved PFS after ASCT is attributed to cytoreduction from myeloablative chemotherapy. However, ASCT results in immune effects beyond cytoreduction, including inflammation, lymphodepletion, T cell priming via immunogenic cell death, and disruption of the tumor BM microenvironment. In fact, a small subset of patients achieve very long-term control of disease post-ASCT, akin to that seen in the context of immune-mediated graft-vs.-myeloma effects after allogeneic SCT. These clinical observations coupled with recent definitive studies in mice demonstrating that progression after ASCT represents immune escape as a consequence of T cell exhaustion, highlight the potential for new immunotherapy maintenance strategies to prevent myeloma progression following consolidation with ASCT.

Anti-Cancer Auto-Antibodies: Roles, Applications and Open Issues

Auto-antibodies are classically associated with autoimmune diseases, where they are an integral part of diagnostic panels. However, recent evidence is accumulating on the presence of auto-antibodies against single or selected panels of auto-antigens in many types of cancer. Auto-antibodies might initially represent an epiphenomenon derived from the inflammatory environment induced by the tumor. However, their effect on tumor evolution can be crucial, as is discussed in this paper. It has been demonstrated that some of these auto-antibodies can be used for early detection and cancer staging, as well as for monitoring of cancer regression during treatment and follow up. Interestingly, certain auto-antibodies were found to promote cancer progression and metastasis, while others contribute to the body's defense against it. Moreover, auto-antibodies are of a polyclonal nature, which means that often several antibodies are involved in the response to a single tumor antigen. Dissection of these antibody specificities is now possible, allowing their identification at the genetic, structural, and epitope levels. In this review, we report the evidence available on the presence of auto-antibodies in the main cancer types and discuss some of the open issues that still need to be addressed by the research community.

The Immune Microenvironment in Multiple Myeloma: Friend or Foe?

Simple Summary

The crosstalk between multiple myeloma and immune cells within the bone marrow niche has been identified as an emerging hallmark of this hematological disease. As our knowledge on this interplay increases, it becomes more evident that successful treatment approaches need to boost the body’s natural defenses through immunotherapy. The present review will focus on the mechanisms by which myeloma cancer cells turn immune populations into their “partners in crime”. Additionally, we will provide an overview of currently ongoing pre-clinical studies targeting the bone marrow immune microenvironment.

Abstract

Multiple myeloma (MM) is one of the most prevalent hematological cancers worldwide, characterized by the clonal expansion of neoplastic plasma cells in the bone marrow (BM). A combination of factors is implicated in disease progression, including BM immune microenvironment changes. Increasing evidence suggests that the disruption of immunological processes responsible for myeloma control ultimately leads to the escape from immune surveillance and resistance to immune effector function, resulting in an active form of myeloma. In fact, one of the hallmarks of MM is the development of a permissive BM milieu that provides a growth advantage to the malignant cells. Consequently, a better understanding of how myeloma cells interact with the BM niche compartments and disrupt the immune homeostasis is of utmost importance to develop more effective treatments. This review focuses on the most up-to-date knowledge regarding microenvironment-related mechanisms behind MM immune evasion and suppression, as well as promising molecules that are currently under pre-clinical tests targeting immune populations.

Vaccine Therapies for Cancer: Then and Now

There are strong biologic and preclinical rationales for the development of therapeutic cancer vaccines; however, the clinical translation of this treatment strategy has been challenging. It is now understood that many previous clinical trials of cancer vaccines used target antigens or vaccine designs that inherently lacked sufficient immunogenicity to induce clinical responses. Despite the historical track record, breakthrough advances in cancer immunobiology and vaccine technologies have supported continued interest in therapeutic cancer vaccinations, with the hope that next-generation vaccine strategies will enable patients with cancer to develop long-lasting anti-tumor immunity. There has been substantial progress identifying antigens and vaccine vectors that lead to strong and broad T cell responses, tailoring vaccine designs to achieve optimal antigen presentation, and finding combination partners employing complementary mechanisms of action (e.g., checkpoint inhibitors) to overcome the diverse methods cancer cells use to evade and suppress the immune system. Results from randomized, phase 3 studies testing therapeutic cancer vaccines based on these advances are eagerly awaited. Here, we summarize the successes and failures in the clinical development of cancer vaccines, address how this historical experience and advances in science and technology have shaped efforts to improve vaccines, and offer a clinical perspective on the future role of vaccine therapies for cancer.

Inhibition of MDM2 Promotes Antitumor Responses in p53 Wild-Type Cancer Cells through Their Interaction with the Immune and Stromal Microenvironment

p53 is a transcription factor that plays a central role in guarding the genomic stability of cells through cell-cycle arrest or induction of apoptosis. However, the effects of p53 in antitumor immunity are poorly understood. To investigate the role of p53 in controlling tumor-immune cell cross-talk, we studied murine syngeneic models treated with HDM201, a potent and selective second-generation MDM2 inhibitor. In response to HDM201 treatment, the percentage of dendritic cells increased, including the CD103⁺ antigen cross-presenting subset. Furthermore, HDM201 increased the percentage of Tbet⁺Eomes⁺ CD8⁺ T cells and the CD8⁺/Treg ratio within the tumor. These immunophenotypic changes were eliminated with the knockout of p53 in tumor cells. Enhanced expression of CD80 on tumor cells was observed in vitro and in vivo, which coincided with T-cell-mediated tumor cell killing. Combining HDM201 with PD-1 or PD-L1 blockade increased the number of complete tumor regressions. Responding mice developed durable, antigen-specific memory T cells and rejected subsequent tumor implantation. Importantly, antitumor activity of HDM201 in combination with PD-1/PD-L1 blockade was abrogated in p53-mutated and knockout syngeneic tumor models, indicating the effect of HDM201 on the tumor is required for triggering antitumor immunity. Taken together, these results demonstrate that MDM2 inhibition triggers adaptive immunity, which is further enhanced by blockade of PD-1/PD-L1 pathway, thereby providing a rationale for combining MDM2 inhibitors and checkpoint blocking antibodies in patients with wild-type p53 tumors. SIGNIFICANCE: This study provides a mechanistic rationale for combining checkpoint blockade immunotherapy with MDM2 inhibitors in patients with wild-type p53 tumors.

The Role of Tumor Microenvironment in Multiple Myeloma Development and Progression

Simple Summary

Multiple Myeloma (MM) is a hematologic malignancy caused by aberrant plasma cell proliferation in the bone marrow (BM) and constitutes the second most common hematological disease after non-Hodgkin lymphoma. The disease progression is drastically regulated by the immunosuppressive tumor microenvironment (TME) generated by soluble factors and different cells that naturally reside in the BM. This microenvironment does not remain unchanged and alterations favor cancer dissemination. Despite therapeutic advances over the past 15 years, MM remains incurable and therefore understanding the elements that control the TME in MM would allow better-targeted therapies to cure this disease. In this review, we discuss the main events and changes that occur in the BM milieu during MM development.

Abstract

Multiple myeloma (MM) is a hematologic cancer characterized by clonal proliferation of plasma cells in the bone marrow (BM). The progression, from the early stages of the disease as monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) to MM and occasionally extramedullary disease, is drastically affected by the tumor microenvironment (TME). Soluble factors and direct cell–cell interactions regulate MM plasma cell trafficking and homing to the BM niche. Mesenchymal stromal cells, osteoclasts, osteoblasts, myeloid and lymphoid cells present in the BM create a unique milieu that favors MM plasma cell immune evasion and promotes disease progression. Moreover, TME is implicated in malignant cell protection against anti-tumor therapy. This review describes the main cellular and non-cellular components located in the BM, which condition the immunosuppressive environment and lead the MM establishment and progression.

PD-L1/PD-1 Axis in Multiple Myeloma Microenvironment and a Possible Link with CD38-Mediated Immune-Suppression

The emerging role of the PD-1/PD-L1 axis in MM immune-microenvironment has been highlighted by several studies. However, discordant data have been reported on PD-1/PD-L1 distribution within the bone marrow (BM) microenvironment of patients with monoclonal gammopathies. In addition, the efficacy of PD-1/PD-L1 blockade as a therapeutic strategy to reverse myeloma immune suppression and inhibit myeloma cell survival still remains unknown. Recent data suggest that, among the potential mechanisms behind the lack of responsiveness or resistance to anti-PD-L1/PD-1 antibodies, the CD38 metabolic pathways involving the immune-suppressive factor, adenosine, could play an important role. This review summarizes the available data on PD-1/PD-L1 expression in patients with MM, reporting the main mechanisms of regulation of PD-1/PD-L1 axis. The possible link between the CD38 and PD-1/PD-L1 pathways is also reported, highlighting the rationale for the potential use of a combined therapeutic approach with CD38 blocking agents and anti-PD-1/PD-L1 antibodies in order to improve their anti-tumoral effect in MM patients.

The Role of Antigen Processing and Presentation in Cancer and the Efficacy of Immune Checkpoint Inhibitor Immunotherapy

Recent clinical successes of cancer immunotherapy using immune checkpoint inhibitors (ICIs) are rapidly changing the landscape of cancer treatment. Regardless of initial impressive clinical results though, the therapeutic benefit of ICIs appears to be limited to a subset of patients and tumor types. Recent analyses have revealed that the potency of ICI therapies depends on the efficient presentation of tumor-specific antigens by cancer cells and professional antigen presenting cells. Here, we review current knowledge on the role of antigen presentation in cancer. We focus on intracellular antigen processing and presentation by Major Histocompatibility class I (MHCI) molecules and how it can affect cancer immune evasion. Finally, we discuss the pharmacological tractability of manipulating intracellular antigen processing as a complementary approach to enhance tumor immunogenicity and the effectiveness of ICI immunotherapy.

Preclinical Rationale for Targeting the PD-1/PD-L1 Axis in Combination with a CD38 Antibody in Multiple Myeloma and Other CD38-Positive Malignancies

Simple Summary

The CD38-targeting antibody daratumumab mediates its anti-myeloma activities not only through direct effects on tumor cells, but also by its effects on T-cell immunity through depletion of CD38⁺ immune suppressor cells. We hypothesized that combining daratumumab with modulators of other potent immune inhibitory pathways, such as the PD-1/PD-L1 axis, may further improve its efficacy. We show that during MM progression there is increased expression of the PD-1/PD-L1 pathway components in the bone marrow microenvironment. Although nivolumab (a PD-1 checkpoint inhibitor) moderately increased T-cell frequencies in ex vivo experiments with bone marrow samples from MM patients, no single agent activity was observed, and addition of nivolumab did not enhance the activity of daratumumab in these short-term assays. However, with a longer treatment duration, in mouse experiments, we demonstrate that anti-CD38 and anti-PD-1 antibodies synergize to eradicate MM cells. In addition, our results suggest that this combined immunotherapeutic approach may also be beneficial in other CD38-positive malignancies.

Abstract

The CD38-targeting antibody daratumumab mediates its anti-myeloma activities not only through Fc-receptor-dependent effector mechanisms, but also by its effects on T-cell immunity through depletion of CD38⁺ regulatory T-cells, regulatory B-cells, and myeloid-derived suppressor cells. Therefore, combining daratumumab with modulators of other potent immune inhibitory pathways, such as the PD-1/PD-L1 axis, may further improve its efficacy. We show that multiple myeloma (MM) cells from relapsed/refractory patients have increased expression of PD-L1, compared to newly diagnosed patients. Furthermore, PD-1 is upregulated on T-cells from both newly diagnosed and relapsed/refractory MM patients, compared to healthy controls. In short-term experiments with bone marrow samples from MM patients, daratumumab-mediated lysis was mainly associated with the MM cells’ CD38 expression levels and the effector (NK-cells/monocytes/T-cells)-to-target ratio, but not with the PD-L1 expression levels or PD-1⁺ T-cell frequencies. Although PD-1 blockade with nivolumab did not affect MM cell viability or enhanced daratumumab-mediated lysis in short-term ex vivo experiments, nivolumab resulted in a mild but clear increase in T-cell numbers. Moreover, with a longer treatment duration, PD-1 blockade markedly improved anti-CD38 antibody-mediated cytotoxicity in vivo in murine CD38⁺ tumor models. In conclusion, dual targeting of CD38 and PD-1 may represent a promising strategy for treating MM and other CD38-positive malignancies.

Pharmacological combination of nivolumab with dendritic cell vaccines in cancer immunotherapy: An overview

In the last decade, immunotherapy led to a paradigm shift in the treatment of numerous malignancies. Alongside with monoclonal antibodies blocking programmed cell death receptor-1 (PD-1)/PD-L1 and cytotoxic T- lymphocyte antigen 4 (CTLA-4) immune checkpoints, cell-based approaches such as CAR-T cells and dendritic cell (DC) vaccines have strongly contributed to pushing forward this thrilling field. While initial strategies were mainly focused on monotherapeutic regimens, it is now consensual that the combination of immunotherapies tackling multiple cancer hallmarks can result in superior clinical outcomes. Here, we review in depth the pharmacological combination of DC-based vaccines that boost tumour elimination by eliciting and expanding effector immune cells, with the PD-1 inhibitor Nivolumab that allows blocking key tumour immune escape mechanisms. This combination represents an important step in cancer therapy, with a significant enhancement in patient survival in several types of tumours, paving an important way in establishing combinatorial immunotherapeutic strategies as first-line treatments.

Emerging agents and regimens for multiple myeloma

The outcomes of multiple myeloma (MM) have been improved significantly with the therapies incorporating proteasome inhibitors (PI), immunomodulatory drugs, monoclonal antibodies (MoAb) and stem cell transplantation. However, relapsed and refractory MM (RRMM) remains a major challenge. Novel agents and regimens are under active clinical development. These include new PIs such as ixazomib, marizomib, and oprozomib; new MoAbs such as isatuximab and MOR202; novel epigenetic agent ricolinostat and novel cytokines such as siltuximab. Recently, the first XPO-1 inhibitor, selinexor, was approved for RRMM. BCMA-targeted BiTE, antibody-drug conjugates and CAR-T cells have the potential to revolutionize the therapy for RRMM. In this review, we summarized the latest clinical development of these novel agents and regimens.

Dendritic cell vaccine immunotherapy; the beginning of the end of cancer and COVID-19. A hypothesis

Immunotherapy is the newest approach to combat cancer. It can be achieved using several strategies, among which is the dendritic cell (DC) vaccine therapy. Several clinical trials are ongoing using DC vaccine therapy either as a sole agent or in combination with other interventions to tackle different types of cancer. Immunotherapy can offer a potential treatment to coronavirus disease 2019 (COVID-19) the worst pandemic facing this generation, a disease with deleterious effects on the health and economic systems worldwide. We hypothesize that DC vaccine therapy may provide a potential treatment strategy to help combat COVID-19. Cancer patients are at the top of the vulnerable population owing to their immune-compromised status. In this review, we discuss DC vaccine therapy in the light of the body's immunity, cancer, and newly emerging infections such as COVID-19 in hopes of better-customized treatment options for patients with multiple comorbidities.