High-dose RHAMM-R3 peptide vaccination for patients with acute myeloid leukemia, myelodysplastic syndrome and multiple myeloma

Breaking Boundaries: Immunotherapy for Myeloid Malignancies

Immunotherapy has revolutionized the treatment of myeloid oncologic diseases, particularly for patients resistant to chemotherapy or ineligible for allogeneic stem cell transplantation due to age or fitness constraints. As our understanding of the immunopathogenesis of myeloid malignancies expands, so too do the treatment options available to patients. Immunotherapy in myeloid malignancies, however, faces numerous challenges due to the dynamic nature of the disease, immune dysregulation, and the development of immune evasion mechanisms. This review outlines the progress made in the field of immunotherapy for myeloid malignancies, addresses its challenges, and provides insights into future directions in the field.

Advances and challenges in anti-cancer vaccines for multiple myeloma

Multiple myeloma (MM) is a hematological cancer marked by plasma cell accumulation in the bone marrow. Despite treatment advancements, MM remains incurable in most patients. MM-associated immune dysregulation fosters disease progression, prompting research into immunotherapy to combat the disease. An area of immunotherapy investigation is the design of myeloma vaccine therapy to reverse tumor-associated immune suppression and elicit tumor-specific immune responses to effectively target MM cells. This article reviews vaccine immunotherapy for MM, categorizing findings by antigen type and delivery method. Antigens include idiotype (Id), tumor-associated (TAA), tumor-specific (TSA), and whole tumor lysate. Myeloma vaccination has so far shown limited clinical efficacy. However, further studies are essential to optimize various aspects, including antigen and patient selection, vaccine timing and sequencing, and rational combinations with emerging MM treatments.

The Immunotherapy of Acute Myeloid Leukemia: A Clinical Point of View

The potential of the immune system to eradicate leukemic cells has been consistently demonstrated by the Graft vs. Leukemia effect occurring after allo-HSCT and in the context of donor leukocyte infusions. Various immunotherapeutic approaches, ranging from the use of antibodies, antibody-drug conjugates, bispecific T-cell engagers, chimeric antigen receptor (CAR) T-cells, and therapeutic infusions of NK cells, are thus currently being tested with promising, yet conflicting, results. This review will concentrate on various types of immunotherapies in preclinical and clinical development, from the point of view of a clinical hematologist. The most promising therapies for clinical translation are the use of bispecific T-cell engagers and CAR-T cells aimed at lineage-restricted antigens, where overall responses (ORR) ranging from 20 to 40% can be achieved in a small series of heavily pretreated patients affected by refractory or relapsing leukemia. Toxicity consists mainly in the occurrence of cytokine-release syndrome, which is mostly manageable with step-up dosing, the early use of cytokine-blocking agents and corticosteroids, and myelosuppression. Various cytokine-enhanced natural killer products are also being tested, mainly as allogeneic off-the-shelf therapies, with a good tolerability profile and promising results (ORR: 20-37.5% in small trials). The in vivo activation of T lymphocytes and NK cells via the inhibition of their immune checkpoints also yielded interesting, yet limited, results (ORR: 33-59%) but with an increased risk of severe Graft vs. Host disease in transplanted patients. Therefore, there are still several hurdles to overcome before the widespread clinical use of these novel compounds.

Immunotherapies of acute myeloid leukemia: Rationale, clinical evidence and perspective

Acute myeloid leukemia (AML) is a prevalent hematological malignancy that exhibits a wide array of molecular abnormalities. Although traditional treatment modalities such as chemotherapy and allogeneic stem cell transplantation (HSCT) have become standard therapeutic approaches, a considerable number of patients continue to face relapse and encounter a bleak prognosis. The emergence of immune escape, immunosuppression, minimal residual disease (MRD), and other contributing factors collectively contribute to this challenge. Recent research has increasingly highlighted the notable distinctions between AML tumor microenvironments and those of healthy individuals. In order to investigate the potential therapeutic mechanisms, this study examines the intricate transformations occurring between leukemic cells and their surrounding cells within the tumor microenvironment (TME) of AML. This review classifies immunotherapies into four distinct categories: cancer vaccines, immune checkpoint inhibitors (ICIs), antibody-based immunotherapies, and adoptive T-cell therapies. The results of numerous clinical trials strongly indicate that the identification of optimal combinations of novel agents, either in conjunction with each other or with chemotherapy, represents a crucial advancement in this field. In this review, we aim to explore the current and emerging immunotherapeutic methodologies applicable to AML patients, identify promising targets, and emphasize the crucial requirement to augment patient outcomes. The application of these strategies presents substantial therapeutic prospects within the realm of precision medicine for AML, encompassing the potential to ameliorate patient outcomes.

Vaccines: a promising therapy for myelodysplastic syndrome

Myelodysplastic neoplasms (MDS) define clonal hematopoietic malignancies characterized by heterogeneous mutational and clinical spectra typically seen in the elderly. Curative treatment entails allogeneic hematopoietic stem cell transplant, which is often not a feasible option due to older age and significant comorbidities. Immunotherapy has the cytotoxic capacity to elicit tumor-specific killing with long-term immunological memory. While a number of platforms have emerged, therapeutic vaccination presents as an appealing strategy for MDS given its promising safety profile and amenability for commercialization. Several preclinical and clinical trials have investigated the efficacy of vaccines in MDS; these include peptide vaccines targeting tumor antigens, whole cell-based vaccines and dendritic cell-based vaccines. These therapeutic vaccines have shown acceptable safety profiles, but consistent clinical responses remain elusive despite robust immunological reactions. Combining vaccines with immunotherapeutic agents holds promise and requires further investigation. Herein, we highlight therapeutic vaccine trials while reviewing challenges and future directions of successful vaccination strategies in MDS.

Hyaluronic Acid as a Modern Approach in Anticancer Therapy-Review

Hyaluronic acid (HA) is a linear polysaccharide and crucial component of the extracellular matrix (ECM), maintaining tissue hydration and tension. Moreover, HA contributes to embryonic development, healing, inflammation, and cancerogenesis. This review summarizes new research on the metabolism and interactions of HA with its binding proteins, known as hyaladherins (CD44, RHAMM), revealing the molecular basis for its distinct biological function in the development of cancer. The presence of HA on the surface of tumor cells is a sign of an adverse prognosis. The involvement of HA in malignancy has been extensively investigated using cancer-free naked mole rats as a model. The HA metabolic components are examined for their potential impact on promoting or inhibiting tumor formation, proliferation, invasion, and metastatic spread. High molecular weight HA is associated with homeostasis and protective action due to its ability to preserve tissue integrity. In contrast, low molecular weight HA indicates a pathological condition in the tissue and plays a role in pro-oncogenic activity. A systematic approach might uncover processes related to cancer growth, establish novel prognostic indicators, and identify potential targets for treatment action.

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.

The role of RHAMM in cancer: Exposing novel therapeutic vulnerabilities

Receptor for hyaluronic acid-mediated motility (RHAMM) is a cell surface receptor for hyaluronic acid that is critical for cell migration and a cell cycle protein involved in microtubule assembly and stability. These functions of RHAMM are required for cellular stress responses and cell cycle progression but are also exploited by tumor cells for malignant progression and metastasis. RHAMM is often overexpressed in tumors and is an independent adverse prognostic factor for a number of cancers such as breast and prostate. Interestingly, pharmacological or genetic inhibition of RHAMM in vitro and in vivo ablates tumor invasiveness and metastatic spread, implicating RHAMM as a potential therapeutic target to restrict tumor growth and improve patient survival. However, RHAMM’s pro-tumor activity is dependent on its subcellular distribution, which complicates the design of RHAMM-directed therapies. An alternative approach is to identify downstream signaling pathways that mediate RHAMM-promoted tumor aggressiveness. Herein, we discuss the pro-tumoral roles of RHAMM and elucidate the corresponding regulators and signaling pathways mediating RHAMM downstream events, with a specific focus on strategies to target the RHAMM signaling network in cancer cells.

The Role of T Cell Immunity in Monoclonal Gammopathy and Multiple Myeloma: From Immunopathogenesis to Novel Therapeutic Approaches

Multiple Myeloma (MM) is a malignant growth of clonal plasma cells, typically arising from asymptomatic precursor conditions, namely monoclonal gammopathy of undetermined significance (MGUS) and smoldering MM (SMM). Profound immunological dysfunctions and cytokine deregulation are known to characterize the evolution of the disease, allowing immune escape and proliferation of neoplastic plasma cells. In the past decades, several studies have shown that the immune system can recognize MGUS and MM clonal cells, suggesting that anti-myeloma T cell immunity could be harnessed for therapeutic purposes. In line with this notion, chimeric antigen receptor T cell (CAR-T) therapy is emerging as a novel treatment in MM, especially in the relapsed/refractory disease setting. In this review, we focus on the pivotal contribution of T cell impairment in the immunopathogenesis of plasma cell dyscrasias and, in particular, in the disease progression from MGUS to SMM and MM, highlighting the potentials of T cell-based immunotherapeutic approaches in these settings.

Increasing Role of Targeted Immunotherapies in the Treatment of AML

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. The standard of care in medically and physically fit patients is intensive induction therapy. The majority of these intensively treated patients achieve a complete remission. However, a high number of these patients will experience relapse. In patients older than 60 years, the results are even worse. Therefore, new therapeutic approaches are desperately needed. One promising approach in high-risk leukemia to prevent relapse is the induction of the immune system simultaneously or after reduction of the initial tumor burden. Different immunotherapeutic approaches such as allogenic stem cell transplantation or donor lymphocyte infusions are already standard therapies, but other options for AML treatment are in the pipeline. Moreover, the therapeutic landscape in AML is rapidly changing, and in the last years, a number of immunogenic targets structures eligible for specific therapy, risk assessment or evaluation of disease course were determined. For example, leukemia-associated antigens (LAA) showed to be critical as biomarkers of disease state and survival, as well as markers of minimal residual disease (MRD). Yet many mechanisms and properties are still insufficiently understood, which also represents a great potential for this form of therapy. Therefore, targeted therapy as immunotherapy could turn into an efficient tool to clear residual disease, improve the outcome of AML patients and reduce the relapse risk. In this review, established but also emerging immunotherapeutic approaches for AML patients will be discussed.

Tumor-Tissue Expression of the Hyaluronic Acid Receptor RHAMM Predicts Histological Transformation in Follicular Lymphoma Patients

Histological transformation (HT) remains the leading cause of mortality in follicular lymphoma (FL), underlining the need to identify reliable transformation predictors. The hyaluronic acid receptors CD44 and the receptor for hyaluronan mediated motility (RHAMM, also known as HMMR and CD168), have been shown to be involved in the pathogeneses of both solid tumors and hematological malignancies. In an attempt to improve risk stratification, expression of RHAMM and CD44 were evaluated by immunohistochemistry and digital image analysis in pre-therapeutic tumor-tissue biopsies from FL patients, either without (nt-FL, n = 34), or with (st-FL, n = 31) subsequent transformation, and in paired biopsies from the transformed lymphomas (tFL, n = 31). At the time of initial diagnosis, samples from st-FL patients had a higher expression of RHAMM compared with samples from nt-FL patients (p < 0.001). RHAMM expression further increased in tFL samples following transformation (p < 0.001). Evaluation of CD44 expression showed no differences in expression comparing nt-FL, st-FL, and tFL samples. Shorter transformation-free survival was associated with high tumoral and intrafollicular RHAMM expression, as well as with low intrafollicular CD44 expression (p = 0.002, p < 0.001, and p = 0.034, respectively). Our data suggest that high tumor-tissue RHAMM expression predicts the risk of shorter transformation-free survival in FL patients already at initial diagnosis.

Research progress on dendritic cell vaccines in cancer immunotherapy

Dendritic cell (DC) vaccines induce specific immune responses that can selectively eliminate target cells. In recent years, many studies have been conducted to explore DC vaccination in the treatment of hematological malignancies, including acute myeloid leukemia and myelodysplastic syndromes, as well as other nonleukemia malignancies. There are at least two different strategies that use DCs to promote antitumor immunity: in situ vaccination and canonical vaccination. Monocyte-derived DCs (mo-DCs) and leukemia-derived DCs (DCleu) are the main types of DCs used in vaccines for AML and MDS thus far. Different cancer-related molecules such as peptides, recombinant proteins, apoptotic leukemic cells, whole tumor cells or lysates and DCs/DCleu containing a vaster antigenic repertoire with RNA electroporation, have been used as antigen sources to load DCs. To enhance DC vaccine efficacy, new strategies, such as combination with conventional chemotherapy, monospecific/bispecific antibodies and immune checkpoint-targeting therapies, have been explored. After a decade of trials and tribulations, much progress has been made and much promise has emerged in the field. In this review we summarize the recent advances in DC vaccine immunotherapy for AML/MDS as well as other nonleukemia malignancies.

The cell cycle-related genes RHAMM, AURKA, TPX2, PLK1, and PLK4 are associated with the poor prognosis of breast cancer patients

Breast cancer is the third most common type of cancer diagnosed. Cell cycle is a complex but highly organized and controlled process, in which normal cells sense mitogenic growth signals that instruct them to enter and progress through their cell cycle. This process culminates in cell division generating two daughter cells with identical amounts of genetic material. Uncontrolled proliferation is one of the hallmarks of cancer. In this study, we analyzed the expression of the cell cycle-related genes receptor for hyaluronan (HA)-mediated motility (RHAMM), AURKA, TPX2, PLK1, and PLK4 and correlated them with the prognosis in a collective of 3952 breast cancer patients. A high messenger RNA expression of all studied genes correlated with a poor prognosis. Stratifying the patients according to the expression of hormonal receptors, we found that in patients with estrogen and progesterone receptor-positive and human epithelial growth factor receptor 2-negative tumors, and Luminal A and Luminal B tumors, the expression of the five analyzed genes correlates with worse survival. qPCR analysis of a panel of breast cancer cell lines representative of major molecular subtypes indicated a predominant expression in the luminal subtype. In vitro experiments showed that radiation influences the expression of the five analyzed genes both in luminal and triple-negative model cell lines. Functional analysis of MDA-MB-231 cells showed that small interfering RNA knockdown of PLK4 and TPX2 and pharmacological inhibition of PLK1 had an impact on the cell cycle and colony formation. Looking for a potential upstream regulation by microRNAs, we observed a differential expression of RHAMM, AURKA, TPX2, PLK1, and PLK4 after transfecting the MDA-MB-231 cells with three different microRNAs. Survival analysis of miR-34c-5p, miR-375, and miR-142-3p showed a different impact on the prognosis of breast cancer patients. Our study suggests that RHAMM, AURKA, TPX2, PLK1, and PLK4 can be used as potential targets for treatment or as a prognostic value in breast cancer patients.

In Silico Model Estimates the Clinical Trial Outcome of Cancer Vaccines

Over 30 years after the first cancer vaccine clinical trial (CT), scientists still search the missing link between immunogenicity and clinical responses. A predictor able to estimate the outcome of cancer vaccine CTs would greatly benefit vaccine development. Published results of 94 CTs with 64 therapeutic vaccines were collected. We found that preselection of CT subjects based on a single matching HLA allele does not increase immune response rates (IRR) compared with non-preselected CTs (median 60% vs. 57%, p = 0.4490). A representative in silico model population (MP) comprising HLA-genotyped subjects was used to retrospectively calculate in silico IRRs of CTs based on the percentage of MP-subjects having epitope(s) predicted to bind ≥ 1–4 autologous HLA allele(s). We found that in vitro measured IRRs correlated with the frequency of predicted multiple autologous allele-binding epitopes (AUC 0.63–0.79). Subgroup analysis of multi-antigen targeting vaccine CTs revealed correlation between clinical response rates (CRRs) and predicted multi-epitope IRRs when HLA threshold was ≥ 3 (r = 0.7463, p = 0.0004) but not for single HLA allele-binding epitopes (r = 0.2865, p = 0.2491). Our results suggest that CRR depends on the induction of broad T-cell responses and both IRR and CRR can be predicted when epitopes binding to multiple autologous HLAs are considered.

Comprehensive Bioinformatics Analysis to Identify the Gene HMMR Associated With Lung Adenocarcinoma Prognosis and Its Mechanism of Action in Multiple Cancers

Background

Lung cancer is the third most frequently diagnosed cancer in the world, with lung adenocarcinoma (LUAD) as the most common pathological type. But studies on the predictive effect of a single gene on LUAD are limited. We aimed to discover new predictive markers for LUAD.

Methods

Differentially high-expressed genes at each stage were obtained from the TCGA and GTEx databases. The functions of these genes were investigated through GO enrichment and KEGG pathway analyses. Then, the key genes were selected by applying whole gene overall survival time. The expression of the key gene was studied in LUAD, and survival analysis was performed using Kaplan-Meier mapper, followed by univariate and multifactorial COX analysis. Finally, the gene expression and its prognostic significance in the pan-cancer were examined.

Results

A total of 10,106 DEGs were obtained from the two datasets. The top 266 differentially upregulated genes intersected with the top 1,497 overall survival-related genes, and 87 key genes were identified. High-expressed HMMR was associated with a poor prognosis of LUAD. Univariate and multifactorial Cox analysis showed that HMMR was an independent prognostic factor for LUAD patients. A high HMMR expression was strongly associated with the overall survival (OS) and disease-specific survival (DSS) in 11 cancer types and with poorer OS, DSS, and PFI in 10 cancer types.

Conclusion

HMMR may be an independent prognostic indicator and an important biomarker in diagnosing and predicting the survival of LUAD patients. Also, HMMR may be a key predictor of a variety of cancers.

Trial Watch: Adoptive TCR-Engineered T-Cell Immunotherapy for Acute Myeloid Leukemia

Simple Summary

Acute myeloid leukemia (AML) is a type of blood cancer with an extremely grim prognosis. This is due to the fact that the majority of patients will relapse after frontline treatment. Overall survival of relapsed AML is very low, and treatment options are few. T lymphocytes harnessed with antitumor T-cell receptors (TCRs) can produce objective clinical responses in certain cancers, such as melanoma, but have not entered the main road for AML. In this review, we describe the current status of the field of TCR-T-cell therapies for AML.

Abstract

Despite the advent of novel therapies, acute myeloid leukemia (AML) remains associated with a grim prognosis. This is exemplified by 5-year overall survival rates not exceeding 30%. Even with frontline high-intensity chemotherapy regimens and allogeneic hematopoietic stem cell transplantation, the majority of patients with AML will relapse. For these patients, treatment options are few, and novel therapies are urgently needed. Adoptive T-cell therapies represent an attractive therapeutic avenue due to the intrinsic ability of T lymphocytes to recognize tumor cells with high specificity and efficiency. In particular, T-cell therapies focused on introducing T-cell receptors (TCRs) against tumor antigens have achieved objective clinical responses in solid tumors such as synovial sarcoma and melanoma. However, contrary to chimeric antigen receptor (CAR)-T cells with groundbreaking results in B-cell malignancies, the use of TCR-T cells for hematological malignancies is still in its infancy. In this review, we provide an overview of the status and clinical advances in adoptive TCR-T-cell therapy for the treatment of AML.

Vaccine and Cell-based Therapeutic Approaches in Acute Myeloid Leukemia

Over the past decade, our increased understanding of the interactions between the immune system and cancer cells has led to paradigm shifts in the clinical management of solid and hematologic malignancies. The incorporation of immune-targeted strategies into the treatment landscape of acute myeloid leukemia (AML), however, has been challenging. While this is in part due to the inability of the immune system to mount an effective tumor-specific immunogenic response against the heterogeneous nature of AML, the decreased immunogenicity of AML cells also represents a major obstacle in the effort to design effective immunotherapeutic strategies. In fact, AML cells have been shown to employ sophisticated escape mechanisms to evade elimination, such as direct immunosuppression of natural killer cells and decreased surface receptor expression leading to impaired recognition by the immune system. Yet, cellular and humoral immune reactions against tumor-associated antigens (TAA) of acute leukemia cells have been reported and the success of allogeneic stem cell transplantation and monoclonal antibodies in the treatment of AML clearly provides proof that an immunotherapeutic approach is feasible in the management of this disease. This review discusses the recent progress and persisting challenges in cellular immunotherapy for patients with AML.

T-cell-based immunotherapy of acute myeloid leukemia: current concepts and future developments

Acute myeloid leukemia (AML) is a heterogeneous disease linked to a broad spectrum of molecular alterations, and as such, long-term disease control requires multiple therapeutic approaches. Driven largely by an improved understanding and targeting of these molecular aberrations, AML treatment has rapidly evolved over the last 3-5 years. The stellar successes of immunotherapies that harness the power of T cells to treat solid tumors and an improved understanding of the immune systems of patients with hematologic malignancies have led to major efforts to develop immunotherapies for the treatment of patients with AML. Several immunotherapies that harness T cells against AML are in various stages of preclinical and clinical development. These include bispecific and dual antigen receptor-targeting antibodies (targeted to CD33, CD123, CLL-1, and others), chimeric antigen receptor (CAR) T-cell therapies, and T-cell immune checkpoint inhibitors (including those targeting PD-1, PD-L1, CTLA-4, and newer targets such as TIM3 and STING). The current and future directions of these T-cell-based immunotherapies in the treatment landscape of AML are discussed in this review.

Hyaluronan-mediated motility receptor expression functions as a prognostic biomarker in uterine carcinosarcoma based on bioinformatics analysis

OBJECTIVE

Uterine carcinosarcoma (UCS) is a rare, aggressive tumour with a high metastasis rate and poor prognosis. This study aimed to explore potential key genes associated with the prognosis of UCS.

METHODS

Transcriptional expression data were downloaded from the Gene Expression Profiling Interactive Analysis database and differentially expressed genes (DEGs) were subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses using Metascape. A protein-protein interaction network was constructed using the STRING website and Cytoscape software, and the top 30 genes obtained through the Maximal Clique Centrality algorithm were selected as hub genes. These hub genes were validated by clinicopathological and sequencing data for 56 patients with UCS from The Cancer Genome Atlas database.

RESULTS

A total of 1894 DEGs were identified, and the top 30 genes were considered as hub genes. Hyaluronan-mediated motility receptor (HMMR) expression was significantly higher in UCS tissues compared with normal tissues, and elevated expression of HMMR was identified as an independent prognostic factor for shorter survival in patients with UCS.

CONCLUSIONS

These results suggest that HMMR may be a potential biomarker for predicting the prognosis of patients with UCS.

An integrative microenvironment approach for laryngeal carcinoma: the role of immune/methylation/autophagy signatures on disease clinical prognosis and single-cell genotypes

The effects of methylation/autophagy-related genes (MARGs) and immune infiltration in the tumor microenvironment on the prognosis of laryngeal cancer were comprehensively explored in this study. Survival analysis screened out 126 MARGs and 10 immune cells potentially associated with the prognosis of laryngeal carcinoma. Cox and lasso regression analyses were then used to select 8 MARGs (CAPN10, DAPK2, MBTPS2, ST13, CFLAR, FADD, PEX14 and TSC2) and 2 immune cells (Eosinophil and Mast cell) to obtain the prognostic risk scoring system (pRS). The pRS was used to establish a risk prediction model for the prognosis of laryngeal cancer. The predictive ability of the prediction model was evaluated by GEO datasets and our clinical samples. Further analysis revealed that pRS is highly associated with single nucleotide polymorphism (SNP), copy number variation (CNV), immune checkpoint blockade (ICB) therapy and tumor microenvironment. Moreover, the screened pRS-related ceRNA network and circ_0002951/miR-548k/HAS2 pathway provide potential therapeutic targets and biomarkers of laryngocarcinoma. Based on the clustering results of pRS-related genes, single cells were then genotyped and revealed by integrated scRNA-seq in laryngeal cancer samples. Fibroblasts were found enriched in high risk cell clusters at the scRNA-seq level. Fibroblast-related ligand-receptor interactions were then exposed and a neural network-based deep learning model based on these pRS-related hub gene signatures was also established with a high accuracy in cell type prediction. In conclusion, the combination of single-cell and transcriptome laryngeal carcinoma landscape analyses can investigate the link between the tumor microenvironmental and prognostic characteristics.

Identification of HLA-A*0201-restricted CTL Epitopes for MLAA-34-specific Immunotherapy for Acute Monocytic Leukemia

Our previous research has shown that monocytic leukemia-associated antigen-34 (MLAA-34) was a novel antiapoptotic molecule with unique expression in acute monocytic leukemia (M5), making it an ideal target for T-cell-based immunotherapy. Here, we sought to identify HLA-A*0201-restricted cytotoxic T-lymphocyte (CTL) epitope of MLAA-34 by reverse immunology. In all, 10 HLA-A*0201 restricted epitopes of MLAA-34 were predicted by bioinformatics. MLAA-34324-332, MLAA-34293-301, and MLAA-34236-244 showed the strongest HLA-A*0201-binding affinity. The percentages of HLA-A*0201-MLAA-34236-244 tetramer+ CD8+ T cells in MLAA-34236-244-induced CTLs were raised apparently. Enzyme-linked immunospot showed that MLAA-34236-244 and MLAA-34324-332-specific CTLs produced a higher amount of interferon-γ. MLAA-34236-244-induced CTLs presented a stronger cytotoxic effect on THP-1 cells (HLA-A*0201+MLAA-34+) at various effector to target ratios. MLAA-34236-244 peptide vaccine could inhibit the tumor growth and improve mean survival time of leukemia-bearing human peripheral blood lymphocyte reconstituting severe combined immunodeficient mice. Mice immunized with MLAA-34236-244 vaccine had increased percentages of MLAA-34236-244 tetramer+ CD8+ T cells in the spleen after each round of immunization. High-purity CD8+ and CD4+ T cells were sorted by Dynabeads as effector cells. The killing activity of CD8+ T cells was higher than that of CD4+ T cells. CTLs derived from the MLAA-34 peptide vaccine group were significantly higher than other therapeutic groups and showed specific cytotoxicity to THP-1 cells. Increased interferon-γ and interleukin (IL)-2 and decreased IL-10 and IL-4 were seen in the MLAA-34236-244 peptide vaccine group. MLAA-34236-244 peptide (ILDRHNFAI) is an effective HLA-A*0201-restricted CTL epitope and that it may serve as a promising strategy in designing antigen-specific immunotherapy against MLAA-34-positive acute monocytic leukemia.

Quality Is King: Fundamental Insights into Tumor Antigenicity from Virus-Associated Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare skin malignancy that is a paradigm cancer for solid tumor immunotherapy. MCCs associated with Merkel cell polyomavirus (virus-positive MCC [VP-MCC]) or chronic UV exposure (virus-negative MCC [VN-MCC]) are anti-PD(L)1 responsive, despite VP-MCC's low mutational burden. This suggests that antigen quality, not merely mutation quantity, dictates immunotherapy responsiveness, and cell-based therapies targeting optimal antigens may be effective. Despite VP-MCC's antigenic homogeneity, diverse T-cell infiltration patterns are observed, implying microenvironment plasticity and multifactorial contributions to immune recognition. Moreover, VP-MCC exemplifies how antitumor adaptive immunity can provide tumor burden biomarkers for early detection and disease monitoring.

High Expression of Hyaluronan-Mediated Motility Receptor Predicts Adverse Outcomes: A Potential Therapeutic Target for Head and Neck Squamous Cell Carcinoma

Background: Several studies have shown that the hyaluronan-mediated motility receptor (HMMR) is overexpressed in various cancers and could be a potential prognostic factor. However, further research is still required to determine the prognostic value and potential function of HMMR in head and neck squamous cell carcinoma (HNSCC).

Materials and Methods: Transcriptomic expression data were collected from the Cancer Genome Atlas database (TCGA) and Gene Expression Omnibus and the differences in HMMR expression between normal and tumor tissues were analyzed. The correlation between the methylation level of HMMR and its mRNA expression was analyzed via cBioPortal. Additionally, the data obtained from TCGA was analyzed with MethSurv to determine the prognostic value of the HMMR methylation levels in HNSCC. Gene set enrichment analysis (GSEA) and single sample GSEA (ssGSEA) were used to explore the potential biological functions of HMMR.

Results: HMMR was highly expressed in HNSCC tumor tissue compared to normal tissue (p < 0.001). Multivariate analysis (MAV) showed that high HMMR mRNA expression was an independent prognostic factor of overall survival (OS) in TCGA (HR = 1.628, 95% CI: 1.169–2.266, p = 0.004) and GSE41613 data (HR = 2.238, p = 0.013). The methylation level of HMMR negatively correlated with the HMMR expression (R = −0.12, p < 0.001), and patients with low HMMR methylation had worse OS than patients with high methylation (p < 0.001). GSEA found that HMMR expression was associated with the KARS, EMT, and G2M checkpoint pathways, as well as the interferon-gamma and interferon-alpha responses, whereas ssGSEA showed that HMMR expression positively correlated with the infiltration level of Th2 cells. MAV confirmed that high HMMR protein expression was an inferior independent factor for OS (HR = 2.288, p = 0.045) and progression-free survival (HR = 2.247, p = 0.038) in 70 HNSCC.

Conclusions: This study demonstrated that the upregulation of HMMR mRNA and protein in HNSCC is a biomarker for poor prognosis. The biological functions of HMMR are potentially related to the KARS, EMT, and G2M checkpoint pathways, as well as the interferon-gamma and interferon-alpha responses. These findings help to elucidate the role of HMMR in carcinogenesis and lay a foundation for further study.

Trial watch: Peptide vaccines in cancer therapy

Prophylactic vaccination constitutes one of the most prominent medical achievements of history. This concept was first demonstrated by the pioneer work of Edward Jenner, dating back to the late 1790s, after which an array of preparations that confer life-long protective immunity against several infectious agents has been developed. The ensuing implementation of nation-wide vaccination programs has de facto abated the incidence of dreadful diseases including rabies, typhoid, cholera and many others. Among all, the most impressive result of vaccination campaigns is surely represented by the eradication of natural smallpox infection, which was definitively certified by the WHO in 1980. The idea of employing vaccines as anticancer interventions was first theorized in the 1890s by Paul Ehrlich and William Coley. However, it soon became clear that while vaccination could be efficiently employed as a preventive measure against infectious agents, anticancer vaccines would have to (1) operate as therapeutic, rather than preventive, interventions (at least in the vast majority of settings), and (2) circumvent the fact that tumor cells often fail to elicit immune responses. During the past 30 y, along with the recognition that the immune system is not irresponsive to tumors (as it was initially thought) and that malignant cells express tumor-associated antigens whereby they can be discriminated from normal cells, considerable efforts have been dedicated to the development of anticancer vaccines. Some of these approaches, encompassing cell-based, DNA-based and purified component-based preparations, have already been shown to exert conspicuous anticancer effects in cohorts of patients affected by both hematological and solid malignancies. In this Trial Watch, we will summarize the results of recent clinical trials that have evaluated/are evaluating purified peptides or full-length proteins as therapeutic interventions against cancer.

A minority of T cells recognizing tumor-associated antigens presented in self-HLA can provoke antitumor reactivity

Tumor-associated antigens (TAAs) are monomorphic self-antigens that are proposed as targets for immunotherapeutic approaches to treat malignancies. We investigated whether T cells with sufficient avidity to recognize naturally overexpressed self-antigens in the context of self-HLA can be found in the T-cell repertoire of healthy donors. Minor histocompatibility antigen (MiHA)-specific T cells were used as a model, as the influence of thymic selection on the T-cell repertoire directed against MiHA can be studied in both self (MiHApos donors) and non-self (MiHAneg donors) backgrounds. T-cell clones directed against the HLA*02:01-restricted MiHA HA-1H were isolated from HA-1Hneg/HLA-A*02:01pos and HA-1Hpos/HLA-A*02:01pos donors. Of the 16 unique HA-1H–specific T-cell clones, five T-cell clones derived from HA-1Hneg/HLA-A*02:01pos donors and one T-cell clone derived from an HA-1Hpos/HLA-A*02:01pos donor showed reactivity against HA-1Hpos target cells. In addition, in total, 663 T-cell clones (containing at least 91 unique clones expressing different T-cell receptors) directed against HLA*02:01-restricted peptides of TAA WT1-RMF, RHAMM-ILS, proteinase-3-VLQ, PRAME-VLD, and NY-eso-1-SLL were isolated from HLA-A*02:01pos donors. Only 3 PRAME-VLD–specific and one NY-eso-1-SLL–specific T-cell clone provoked interferon-γ production and/or cytolysis upon stimulation with HLA-A*02:01pos malignant cell lines (but not primary malignant samples) naturally overexpressing the TAA. These results show that self-HLA–restricted T cells specific for self-antigens such as MiHA in MiHApos donors and TAAs are present in peripheral blood of healthy individuals. However, clinical efficacy would require highly effective in vivo priming by peptide vaccination in the presence of proper adjuvants or in vitro expansion of the low numbers of self-antigen–specific T cells of sufficient avidity to recognize endogenously processed antigen.

Cellular Immunotherapy for Multiple Myeloma

Cellular immunotherapy for myeloma has the unique potential both to potently kill the malignant clone and to evoke a memory response to protect from relapse. Understanding the complex interactions between the malignant clone and the microenvironment that promote immune escape is critical to evoke effective antimyeloma immunity. Tremendous progress has been made in the area of cancer vaccines and adoptive T-cell therapy in recent years. Careful study of the mechanisms of response and of immune escape will be critical to developing novel combination therapies and ultimately to improve outcomes for patients with myeloma.

Specific T-cell immune responses against colony-forming cells including leukemic progenitor cells of AML patients were increased by immune checkpoint inhibition

The efficacy of immunotherapies in cancer treatment becomes more and more apparent not only in different solid tumors but also in hematological malignancies. However, in acute myeloid leukemia (AML), mechanisms to increase the efficacy of immunotherapeutic approaches have to be further elucidated. Targeting leukemic progenitor and stem cells (LPC/LSC) by specific CTL, for instance, in an adjuvant setting or in minimal residual disease, might be an option to prevent relapse of AML or to treat MRD. Therefore, we investigated the influence of immune checkpoint inhibitors on LAA-specific immune responses by CTL against leukemic myeloid blasts and colony-forming cells including leukemic progenitor cells (CFC/LPC). In functional immunoassays like CFU/CFI (colony-forming units/immunoassays) and ELISpot analysis, we detected specific LAA-directed immune responses against CFC/LPC that are postulated to be the source population of relapse of the disease. The addition of nivolumab (anti-PD-1) significantly increases LAA-directed immune responses against CFC/LPC, no effect is seen when ipilimumab (anti-CTLA-4) is added. The combination of ipilimumab and nivolumab does not improve the effect compared to nivolumab alone. The anti-PD1-directed immune response correlates to PD-L1 expression on progenitor cells. Our data suggest that immunotherapeutic approaches have the potential to target malignant CFC/LPC and anti-PD-1 antibodies could be an immunotherapeutic approach in AML. Moreover, combination with LAA-directed vaccination strategies might also open interesting application possibilities.

HLA class I-restricted T cell epitopes isolated and identified from myeloid leukemia cells

Leukemia-associated antigens (LAAs) and HLA-I epitopes published previously have shown promise in inducing leukemia-specific T cell responses. However, the clinical responses are limited, and clinical effectiveness is yet to be achieved. Limitations, among others, being the LAAs themselves, the indirect approach to HLA-I epitope identification by reverse immunology, and the use of single or few LAAs and HLA-I epitopes, which limits the spectrum of inducible tumor-specific T cells. Use of a direct approach to identify naturally processed and presented HLA-I epitopes from LAAs, and higher numbers of antigens for T cell-mediated immunotherapy for leukemia may enhance clinical responses and broaden clinical effectiveness. In a prior study we used immunoaffinity purification of HLA-I peptide complexes from the differentiated myeloid tumor cell lines MUTZ3 and THP1 coupled to high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS). From this we identified in the current study seven new HLA-I epitopes and the corresponding LAAs for myeloid leukemia. In comparison, the myeloid HLA-I epitopes reported here were generally stronger HLA-binders that induce stronger T cell responses than those previously published, and their source LAAs had higher immunogenicity, higher expression levels in myeloid tumors cells compared to normal hemopoietin and other major normal tissues, and more protein interaction partners, and they are targeted by CD8 T cells in CML patients. This study analyses and compares the LAAs and HLA-I epitopes based on various immunotherapeutic targets selection criteria, and highlights new targets for T cell-mediated immunotherapy for leukemia.

Dissecting the role of hyaluronan synthases in the tumor microenvironment

The tumor microenvironment is becoming a crucial factor in determining the aggressiveness of neoplastic cells. The glycosaminoglycan hyaluronan is one of the principal constituents of both the tumor stroma and the cancer cell surfaces, and its accumulation can dramatically influence patient survival. Hyaluronan functions are dictated by its ability to interact with several signaling receptors that often activate pro-angiogenic and pro-tumorigenic intracellular pathways. Although hyaluronan is a linear, non-sulfated polysaccharide, and thus lacks the ability of the other sulfated glycosaminoglycans to bind and modulate growth factors, it compensates for this by the ability to form hyaluronan fragments characterized by a remarkable variability in length. Here, we will focus on the role of both high and low molecular weight hyaluronan in controlling the hallmarks of cancer cells, including cell proliferation, migration, metabolism, inflammation, and angiogenesis. We will critically assess the multilayered regulation of HAS2, the most critical hyaluronan synthase, and its role in cancer growth, metabolism, and therapy.

Cellular immunotherapy as a therapeutic approach in multiple myeloma

INTRODUCTION

Immunotherapy seeks to restore and augment the unique ability of the immune system to recognize and kill malignant cells. This strategy has previously been incorporated into standard of care in myeloma with the use of immunomodulatory drugs and allogeneic transplant. The following review will discuss the rationale for immunotherapy to reverse critical aspects of the immunosuppressive milieu in myeloma and avenues where cellular therapies are now revolutionizing myeloma treatment. Areas covered: A particular focus is outcomes of clinical trials in myeloma published in PubMed database or abstract form using vaccines or adoptive cell transfer: marrow infiltrating lymphocytes, T-cell receptor and chimeric antigen receptor T cells. Expert commentary: Immunotherapy has extraordinary potential in myeloma. Combinations of cellular therapies with immunomodulatory molecules or checkpoint inhibitors are likely to be synergistic and now underway. Future directions include neoantigen or nanoparticle vaccines and further modifications of engineered T cells such as use of dual-antigens, suicide genes or allogeneic cells.

Immunotherapy in acute myeloid leukemia and myelodysplastic syndromes: The dawn of a new era?

Immunotherapy has revolutionized therapy in both solid and liquid malignancies. The ability to cure acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) with an allogeneic hematopoietic stem cell transplant (HSCT) is proof of concept for the application of immunotherapy in AML and MDS. However, outside of HSCT, only the anti-CD33 antibody drug conjugate gemtuzumab ozogamicin is currently approved as an antibody-targeted therapy for AML. Several avenues of immunotherapeutic drugs are currently in different stages of clinical development. Here, we review recent advances in antibody-based therapy, immune checkpoint inhibitors, vaccines and adoptive cell-based therapy for patients with AML and MDS. First, we discuss different antibody constructs. Immune checkpoint inhibitors targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein-1 (PD-1) and CD47 as well as peptide, dendritic cell and dendritic/AML cell-based vaccines are reviewed next. Lastly, adoptive cell-based therapy including chimeric antigen receptor (CAR)-T cell and NK cell therapy is discussed.

Donor lymphocyte infusion leads to diversity of specific T cell responses and reduces regulatory T cell frequency in clinical responders

T cell responses against malignant cells play a major role in maintaining remission and prolonging overall survival in patients after allogeneic stem cell transplantation and donor lymphocyte infusion (DLI) due to graft-versus-leukemia effect. For better characterization of the T cell responses, we assessed frequency and diversity of leukemia-associated antigen (LAA)-specific cytotoxic T cells using ELISpot and pMHC multimer assays and analyzed the frequency of regulatory T cells (Treg) as well as cytokine profiles before/after DLI. The data were correlated to the clinical course of patients. Significantly more LAA-derived T cell epitopes (p = 0.02) were recognized in clinical responders (R) when compared to nonresponders (NR). In addition, pMHC multimer-based flow cytometry showed a significantly higher frequency of LAA-specific T cells in R versus NR. The frequency of Treg in R decreased significantly (p = 0.008) while keeping stable in NR. No differences in T cell subset analysis before/after DLI were revealed. Clinical responders were correlated to specific immune responses and all clinical responders showed an increase of specific immune responses after DLI. Cytokine assays using enzyme-linked immunosorbent assay showed a significant increase of IL-4 after DLI. Taken together, an increase of specific CTL responses against several LAA after DLI was detected. Moreover, this study suggests that enhanced LAA diversity in T cell responses as well as decreasing numbers of Treg contribute to clinical outcome of patients treated with DLI.

Survivin-peptide vaccination elicits immune response after allogeneic nonmyeloablative transplantation: a safe strategy to enhance the graft versus tumor effect

Allogeneic hematopoietic cell transplantation (allo-HCT) is an adoptive immunotherapy strategy whose effectiveness relies on graft-versus-tumor (GVT) effect. We explored the feasibility of enhancing GVT after allo-HCT by peptide vaccination. Two myeloma patients were transplanted with a fludarabine-total body irradiation conditioning regimen and vaccinated with an HLA-A*0201-restricted modified survivin nonapeptide, plus montanide as adjuvant. At time of first vaccination, one patient had just attained serological remission despite documented relapse after transplant, while the other patient was in stable disease. Both patients had an immune response to vaccination: the frequency of survivin-specific CD8⁺ T cells increased between second and sixth vaccination and accounted for 0.5-0.8% of CD8⁺ cells; CD8⁺ cells were functional in ELISPOT assay. The first patient persists in complete remission with a follow-up of >5 years, while the second patient did not have a clinical response and vaccination was halted. We analyzed the T-cell receptor (TCR) repertoire of the first patient by spectratyping and found that vaccination did not affect the diversity of TCR profile, indicating that survivin clonotypes were probably spread in multiple TCR families. We generated a limited number (n = 4) of survivin-specific T cell clones: three were reactive only against the modified peptide, whereas one clone recognized also the naive peptide. Peptide vaccination is safe and applicable after allo-HCT and elicits an efficient antigen-specific T cell response without causing graft-versus-host disease.

The tumor-associated antigen RHAMM (HMMR/CD168) is expressed by monocyte-derived dendritic cells and presented to T cells

We formerly demonstrated that vaccination with Wilms’ tumor 1 (WT1)-loaded autologous monocyte-derived dendritic cells (mo-DCs) can be a well-tolerated effective treatment in acute myeloid leukemia (AML) patients. Here, we investigated whether we could introduce the receptor for hyaluronic acid-mediated motility (RHAMM/HMMR/CD168), another clinically relevant tumor-associated antigen, into these mo-DCs through mRNA electroporation and elicit RHAMM-specific immune responses. While RHAMM mRNA electroporation significantly increased RHAMM protein expression by mo-DCs, our data indicate that classical mo-DCs already express and present RHAMM at sufficient levels to activate RHAMM-specific T cells, regardless of electroporation. Moreover, we found that RHAMM-specific T cells are present at vaccination sites in AML patients. Our findings implicate that we and others who are using classical mo-DCs for cancer immunotherapy are already vaccinating against RHAMM.

Overcoming multiple myeloma drug resistance in the era of cancer 'omics'

Multiple myeloma (MM) is among the most compelling examples of cancer in which research has markedly improved the length and quality of lives of those afflicted. Research efforts have led to 18 newly approved treatments over the last 12 years, including seven in 2015. However, despite significant improvement in overall survival, MM remains incurable as most patients inevitably, yet unpredictably, develop refractory disease. Recent advances in high-throughput 'omics' techniques afford us an unprecedented opportunity to (1) understand drug resistance at the genomic, transcriptomic, and proteomic level; (2) discover novel diagnostic, prognostic, and therapeutic biomarkers; (3) develop novel therapeutic targets and rational drug combinations; and (4) optimize risk-adapted strategies to circumvent drug resistance, thus bringing us closer to a cure for MM. In this review, we provide an overview of 'omics' technologies in MM biomarker and drug discovery, highlighting recent insights into MM drug resistance gleaned from the use of 'omics' techniques. Moving from the bench to bedside, we also highlight future trends in MM, with a focus on the potential use of 'omics' technologies as diagnostic, prognostic, or response/relapse monitoring tools to guide therapeutic decisions anchored upon highly individualized, targeted, durable, and rationally informed combination therapies with curative potential.

Design of peptide mimetics to block pro-inflammatory functions of HA fragments

Hyaluronan is a simple extracellular matrix polysaccharide that actively regulates inflammation in tissue repair and disease processes. The native HA polymer, which is large (>500 kDa), contributes to the maintenance of homeostasis. In remodeling and diseased tissues, polymer size is strikingly polydisperse, ranging from <10 kDa to >500 kDa. In a diseased or stressed tissue context, both smaller HA fragments and high molecular weight HA polymers can acquire pro-inflammatory functions, which result in the activation of multiple receptors, triggering pro-inflammatory signaling to diverse stimuli. Peptide mimics that bind and scavenge HA fragments have been developed, which show efficacy in animal models of inflammation. These studies indicate both that HA fragments are key to driving inflammation and that scavenging these is a viable therapeutic approach to blunting inflammation in disease processes. This mini-review summarizes the peptide-based methods that have been reported to date for blocking HA signaling events as an anti-inflammatory therapeutic approach.

Immune Therapies in Multiple Myeloma

Treatment paradigms have changed rapidly for multiple myeloma, and immune therapies have taken center stage. Advances in therapies for myeloma have led to a dramatic improvement in the survival of patients with this incurable malignancy. The immune system is significantly impaired in patients with myeloma as a result of the disease leading to suppression of normal plasma cells as well the negative effects on cellular immunity. Given this scenario, immune approaches have not been successful until recently. Monoclonal antibodies directed against CD38 (daratumumab) and SLAMF7 (elotuzumab) are already in the clinic, and several other antibodies directed against different plasma cell antigens are under evaluation. Although immune checkpoint inhibition with PD-1 inhibitors had no clinical efficacy when the inhibitors were used as single agents, it has led to some dramatic results when the inhibitors are combined with immunomodulatory drugs such as lenalidomide and pomalidomide. Vaccination strategies have shown in vivo immune responses but no clear clinical efficacy. Newer approaches to vaccination with multiple antigens, used in combinations with immunomodulatory drugs and in the setting of minimal residual disease, have all increased possibility of this approach succeeding. Ex vivo effector cell expansion also appears to be promising and is in clinical trials. Finally, a chimeric antigen receptor T-cell approach appears to have some promise based on isolated reports of success and remains an area of intense investigation. Immune-based approaches can potentially augment or even supplant some of the current approaches and, given the low toxicity profile, may hold great potential in the early treatment of precursor-stage diseases. Clin Cancer Res; 22(22); 5453-60. ©2016 AACR SEE ALL ARTICLES IN THIS CCR FOCUS SECTION, "MULTIPLE MYELOMA MULTIPLYING THERAPIES".

Advances in immunotherapy in multiple myeloma

PURPOSE OF REVIEW

Here, we explore the significant progress made in the treatment of multiple myeloma, focusing on immunotherapy and the promise it has offered to patients suffering from advanced disease.

RECENT FINDINGS

Multiple myeloma, a B-cell malignancy, is characterized by unregulated plasma cell growth in the bone marrow as well as strong immunosuppression in the tumor microenvironment. mAbs targeting tumor antigens overcome this, increasing T-cell activation, multiple myeloma cell death, and depth of response. Similarly, adoptive T-cell therapy aims to engineer or isolate tumor-specific T cells for a targeted approach. Finally, peptide and dendritic cell/tumor fusion vaccines reeducate the immune system, expanding the immune response and generating long-term memory to prevent relapse of disease. Many of these approaches have been combined with existing therapies to enhance antitumor immunity.

SUMMARY

Immunotherapeutic approaches have remarkably changed the treatment paradigm for multiple myeloma, and encouraging patient responses have warranted further investigation into mAbs, adoptive T-cell therapy, vaccines, and combination therapy.

RHAMM splice variants confer radiosensitivity in human breast cancer cell lines

Biomarkers for prognosis in radiotherapy-treated breast cancer patients are urgently needed and important to stratify patients for adjuvant therapies. Recently, a role of the receptor of hyaluronan-mediated motility (RHAMM) has been suggested for tumor progression. Our aim was (i) to investigate the prognostic value of RHAMM in breast cancer and (ii) to unravel its potential function in the radiosusceptibility of breast cancer cells. We demonstrate that RHAMM mRNA expression in breast cancer biopsies is inversely correlated with tumor grade and overall survival. Radiosusceptibility in vitro was evaluated by sub-G1 analysis (apoptosis) and determination of the proliferation rate. The potential role of RHAMM was addressed by short interfering RNAs against RHAMM and its splice variants. High expression of RHAMMv1/v2 in p53 wild type cells (MCF-7) induced cellular apoptosis in response to ionizing radiation. In comparison, in p53 mutated cells (MDA-MB-231) RHAMMv1/v2 was expressed sparsely resulting in resistance towards irradiation induced apoptosis. Proliferation capacity was not altered by ionizing radiation in both cell lines. Importantly, pharmacological inhibition of the major ligand of RHAMM, hyaluronan, sensitized both cell lines towards radiation induced cell death. Based on the present data, we conclude that the detection of RHAMM splice variants in correlation with the p53 mutation status could help to predict the susceptibility of breast cancer cells to radiotherapy. Additionally, our studies raise the possibility that the response to radiotherapy in selected cohorts may be improved by pharmaceutical strategies against RHAMM and its ligand hyaluronan.

The hyaluronan-mediated motility receptor RHAMM promotes growth, invasiveness and dissemination of colorectal cancer

In colorectal cancer (CRC), RHAMM is an independent adverse prognostic factor. The aim of the study was therefore to investigate on the role of RHAMM as a potential direct driver of cell proliferation and migration in CRC cell lines and to identify pathways dependent on RHAMM in human CRC.

Proliferation, cell cycle alterations and invasive capacity were tested in two RHAMM- and control- knockdown CRC cell lines by flow cytometry and in vitro assays. Tumorigenicity and metastasis formation was assessed in immunodeficient mice. RNA-Seq and immunohistochemistry was performed on six RHAMM+/- primary CRC tumors.

In vitro, silencing of RHAMM inhibited CRC cell migration and invasion by 50% (p<0.01). In vivo, RHAMM knockdown resulted in slower growth, lower tumor size (p<0.001) and inhibition of metastasis (p<0.001). Patients with RHAMM-high CRC had a worse prognosis (p=0.040) and upregulated pathways for cell cycle progression and adhesion turnover.

RHAMM overexpression is correlated with increased migration and invasion of CRC cells, leads to larger, fast growing tumors, and its downregulation essentially abolishes metastasis in mouse models. RHAMM is therefore a promising therapeutic target in all CRC stages as its inhibition affects growth and dissemination of the primary CRC as well as the metastases.

Role of the Immune Response in Disease Progression and Therapy in Multiple Myeloma

Multiple myeloma (MM) is a hematologic cancer derived from malignant plasma cells within the bone marrow. Unlike most solid tumors, which originate from epithelial cells, the myeloma tumor is a plasma cell derived from the lymphoid cell lineage originating from a post-germinal B-cell. As such, the MM plasma cell represents an integral component of the immune system in terms of both antibody production and antigen presentation, albeit not efficiently. This fundamental difference has significant implications when one considers the implications of immunotherapy. In the case of lymphoid malignancies such as myeloma, immune-based strategies must take into consideration this important difference, potentially necessitating immunotherapy targeted toward MM to be altered from that targeted at solid tumors. Typically, the immune system "surveys" cells within our body and is able to recognize and attack cancerous cells that may arise. However, some cancer cells are able to evade immune surveillance and continue to flourish, causing disease. The major mechanism leading to an effective tumor-specific response is one that enables effective antigen processing and presentation with subsequent T-cell activation, expansion, and effective trafficking to the tumor site. Plasma cells employ several mechanisms to escape immune surveillance which include altered interactions with T-cells, DCs, bone marrow stromal cells (BMSC's), and natural killer cells (NK Cells) that can be mediated by immunosuppressive cells such as and myeloid-derived suppressor cells (MDSC's) and cytokines such as IL-10, TGFβ, and IL-6 as well as down-regulation of the antigen processing machinery. Many therapies have been developed to reestablish a functional immune system in MM patients. These include adoptive T-cell therapies to deliver more tumor-specific T-cells, vaccines to increase the tumor-specific precursor frequency of the endogenous T-cell population, immunomodulatory agents (IMiDs) such as thalidomide and lenalidomide to enhance global endogenous immunity, immunostimulatory cytokines, and antibodies to specifically target tumor-specific cell-surface proteins or cytokines. This review will dissect these various approaches currently being explored in MM as well as highlight some future directions for myeloma-specific immune-based strategies.

Antigen Discovery and Therapeutic Targeting in Hematologic Malignancies

Historically, immune-based therapies have played a leading role in the treatment of hematologic malignancies, with the efficacy of stem cell transplantation largely attributable to donor immunity against malignant cells. As new and more targeted immunotherapies have developed, their role in the treatment of hematologic malignancies is evolving and expanding. Herein, we discuss approaches for antigen discovery and review known and novel tumor antigens in hematologic malignancies. We further explore the role of established and investigational immunotherapies in hematologic malignancies, with a focus on personalization of treatment modalities such as cancer vaccines and adoptive cell therapy. Finally, we identify areas of active investigation and development. Immunotherapy is at an exciting crossroads for the treatment of hematologic malignancies, with further investigation aimed at producing effective, targeted immune therapies that maximize antitumor effects while minimizing toxicity.

Peptide vaccination in the presence of adjuvants in patients after hematopoietic stem cell transplantation with CD4+ T cell reconstitution elicits consistent CD8+ T cell responses

Rationale: Patients receiving an allogeneic stem cell graft from cytomegalovirus (CMV) seronegative donors are particularly prone to CMV reactivation with a high risk of disease and mortality. Therefore we developed and manufactured a novel vaccine and initiated a clinical phase I trial with a CMV phosphoprotein 65 (CMVpp65)-derived peptide. Methods: Ten patients after allogeneic stem cell transplantation received four vaccinations at a biweekly interval. All patients were monitored for CMVpp65 antigenemia. Flow cytometry for CMV-specific CD8+ and γδ T cells as well as neutralizing anti-CMV antibodies were correlated to clinical parameters. Results: The vaccination was well tolerated. Seven of nine patients cleared CMVpp65 antigenemia after four vaccinations and are still free from antigenemia to this day. Two patients with CMV reactivation showed persisting CMV antigenemia. One patient received prophylactic vaccination and did not develop antigenemia. An increase of up to six-fold in frequency of both CMV-specific CD8+ T cells and/or Vδ2negative γδ T cells was detected. Titers of neutralizing antibodies increased up to the tenfold. Humoral and cellular immune responses correlated with clearance of CMV. Conclusion: In summary, CMVpp65 peptide vaccination for patients after allogeneic stem cell transplantation at high risk for CMV reactivation was safe, well tolerated and clinically encouraging. A study in solid-organ transplant patients is ongoing.

Redox Responsive Hyaluronic Acid Nanogels for Treating RHAMM (CD168) Over-expressive Cancer, both Primary and Metastatic Tumors

It remains a substantial challenge to targetedly deliver drug to both primary tumors and metastatic lesions employing a single nanoparticle delivery system. Here aiming at the receptor for hyaluronic acid mediated motility (RHAMM or CD168), a specific receptor for hyaluronic acid (HA), the bioreductive responsive HA nanogels loaded doxorubicin were prepared. The targeting effects of HA nanogels in high RHAMM-expressed cancer cells, primary and metastatic tumors were investigated. It was found that HA nanogels show a strong in vitro and in vivo RHAMM-mediated cellular uptake and drug delivery. The cellular uptake of HA nanogels in high RHAMM-expressed LNCaP and H22 cells was far more than the uptake in low RHAMM-expressed NIH3T3 cells. The IC50 value of drug-loaded HA nanogels against H22 cells was lower than that of free drug. In vivo antitumor activity examinations showed that the HA nanogels not only had significantly superior antitumor efficacy in murine H22 and human LNCaP tumor-bearing mice but also exhibited much deep tumor penetration. The drug delivery of lymph node metastasis by systemically administering HA nanogels demonstrated that the HA nanogels could sufficiently increase drug concentration in metastatic lymph node by RHAMM-HA interaction and inhibit the growth of metastatic lymph node, even completely heal malignant lymph node metastasis. Thus, RHAMM-directed drug delivery is a promising therapy route for treating both primary and metastatic tumors.

Role of Immunotherapy in Targeting the Bone Marrow Microenvironment in Multiple Myeloma: An Evolving Therapeutic Strategy

Multiple myeloma (referred to henceforth as myeloma) is a B-cell malignancy characterized by unregulated growth of plasma cells in the bone marrow. The treatment paradigm for myeloma underwent significant evolution in the last decade, with an improved understanding of the pathogenesis of the disease as well as the development of therapeutic agents that target not only the tumor cells but also their microenvironment. Despite these therapeutic advances, the prognosis of patients with relapsed or refractory myeloma remains poor. Accordingly, a need exists for new therapeutic avenues that can overcome resistance to current therapies and improve survival outcomes. In addition, myeloma is associated with progressive immune dysregulation, with defects in T-cell immunity, natural killer cell function, and the antigen-presenting capacity of dendritic cells, resulting in a tumor microenvironment that promotes disease tolerance and progression. Together, the immunosuppressive microenvironment and oncogenic mutations activate signaling networks that promote myeloma cell survival. Immunotherapy incorporates novel treatment options (e.g., monoclonal antibodies, antibody-drug conjugates, chimeric antigen receptor T-cell therapy, immune checkpoint inhibitors, bispecific antibodies, and tumor vaccines) either alone or in combination with existing lines of therapies (e.g., immunomodulatory agents, proteasome inhibitors, and histone deacetylase inhibitors) to enhance the host anti myeloma immunity within the bone marrow microenvironment and improve clinical response. Following the U.S. Food and Drug Administration approval of daratumumab and elotuzumab in 2015, more immunotherapeutic agents are expected to be become available as valuable treatment options in the near future. This review provides a basic understanding of the role of immunotherapy in modulating the bone marrow tumor microenvironment and its role in the treatment of myeloma. Clinical efficacy and safety of recently approved therapeutic monoclonal antibodies (daratumumab, elotuzumab) are discussed, along with the therapeutic potential of emerging immunotherapies (antibody-drug conjugates, chimeric antigen receptor T-cell therapy, tumor vaccines, and immune checkpoint inhibitors).