Gene expression profiling and real-time PCR analyses identify novel potential cancer-testis antigens in multiple myeloma

Development of Cancer Immunotherapies

Cancer immunotherapy, or the utilization of components of the immune system to target and eliminate cancer, has become a highly active area of research in the past several decades and a common treatment strategy for several cancer types. The concept of harnessing the immune system for this purpose originated over 100 years ago when a physician by the name of William Coley successfully treated several of his cancer patients with a combination of live and attenuated bacteria, later known as "Coley's Toxins", after observing a subset of prior patients enter remission following their diagnosis with the common bacterial infection, erysipelas. However, it was not until late in the twentieth century that cancer immunotherapies were developed for widespread use, thereby transforming the treatment landscape of numerous cancer types. Pivotal studies elucidating molecular and cellular functions of immune cells, such as the discovery of IL-2 and production of monoclonal antibodies, fostered the development of novel techniques for studying the immune system and ultimately the development and approval of several cancer immunotherapies by the United States Food and Drug Association in the 1980s and 1990s, including the tuberculosis vaccine-Bacillus Calmette-Guérin, IL-2, and the CD20-targeting monoclonal antibody. Approval of the first therapeutic cancer vaccine, Sipuleucel-T, for the treatment of metastatic castration-resistant prostate cancer and the groundbreaking success and approval of immune checkpoint inhibitors and chimeric antigen receptor T cell therapy in the last decade, have driven an explosion of interest in and pursuit of novel cancer immunotherapy strategies. A broad range of modalities ranging from antibodies to adoptive T cell therapies is under investigation for the generalized treatment of a broad spectrum of cancers as well as personalized medicine. This chapter will focus on the recent advances, current strategies, and future outlook of immunotherapy development for the treatment of cancer.

Overexpression of TMEFF1 in Endometrial Carcinoma and the Mechanism Underlying its Promotion of Malignant Behavior in Cancer Cells

Background: Although tomoregulin-1 (TMEFF1) is involved in embryonic development and central nervous system regulation and is a cancer suppressor gene in brain cancers, its role in endometrial carcinoma remains unclear.

Methods: The expression and prognostic value of TMEFF1 were analyzed by bioinformatics methods and immunohistochemistry. An endometrial carcinoma cell line with low expression of TMEFF1 was constructed. Scratch and Transwell assays were used to determine the effect of TMEFF1 on cell invasion and migration. Changes in key proteins in the MAPK and PI3K/AKT signaling pathways and in epithelial-mesenchymal transition (EMT)-related proteins were analyzed using western blot. Chromatin immunoprecipitation assay (ChIP) was performed to identify whether the TMEFF1 promoter region binds to the transcription factor p53.

Results: TMEFF1 was significantly upregulated in endometrial carcinoma, was closely associated with FIGO stage (P=0.021) and lymph node metastasis (P=0.029), and was an independent risk factor for prognosis (P=0.044). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed that TMEFF1 and its related genes are involved in the cell cycle, regulation of mitosis, epigenetics, neural development, cell biological signal transduction and some key signal pathways. We also identified kinases, microRNAs and a transcription factor network related to TMEFF1 and the effect of TMEFF1 mutation on prognosis. In vitro knockdown of TMEFF1 significantly inhibited cell invasion and migration. Knockdown of TMEFF1 inhibited Epithelial-mesenchymal transition (EMT) and activation of the MAPK and PI3K/AKT pathways. However, the transcription factor p53 was not found to regulate the TMEFF1 gene.

Conclusion: TMEFF1 plays an important role in endometrial carcinoma and may thus be a potential anticancer therapeutic target for endometrial carcinoma.

Butorphanol Inhibits the Malignant Biological Behaviors of Ovarian Cancer Cells via Down-Regulating the Expression of TMEFF1

Purpose

An important issue with compounds for treating ovarian cancer is the development of drug resistance and side effects. Butorphanol is a synthetic opioid. Opioids have been shown to promote or prevent tumor growth and metastasis. This research aimed to reveal the affection of Butorphanol on the malignant biological behaviors of ovarian cancer cells.

Methods

Different concentrations of Butorphanol were used to treat ovarian cancer cell lines, ES-2 and SKOV3. Biological functions of cells were performed by CCK-8 assay, colony formation assay, apoptosis analysis, transwell assays and scratch assays. The differences in the transcriptome of the Butorphanol treated and negative control (NC) cells were analyzed by RNA-Seq.

Results

Butorphanol treatment significantly inhibited the viability, colony-forming, migration and invasion of ES-2 and SKOV3 cells compared to NC. Furthermore, Butorphanol treatment obviously induced the apoptosis of ES-2 and SKOV3 cells and regulated the expression of apoptosis-related proteins. Additionally, Butorphanol treatment significantly reduced the expression of p-AKT, p-mTOR and P70S6K without affecting the expression of AKT and mTOR in ES-2 and SKOV3 cells. Forty-four genes were identified to up-regulate its expression, while 17 genes were identified to down-regulate its expression in Butorphanol-treated cells. Among them, TMEFF1 was found to be significantly down-regulated in Butorphanol-treated cells. Additionally, the restoration of TMEFF1 expression complemented the inhibitory effect of Butorphanol treatment on cell proliferation and invasion.

Conclusion

In conclusion, Butorphanol is a compound with potential to treat ovarian cancer. TMEFF1 may play a key role in inhibiting the malignant proliferation and metastasis of Butorphanol treatment on ovarian cancer cells.

The transcriptome of CMML monocytes is highly inflammatory and reflects leukemia-specific and age-related alterations

Chronic myelomonocytic leukemia (CMML) is an aggressive myeloid neoplasm of older individuals characterized by persistent monocytosis. Somatic mutations in CMML are heterogeneous and only partially explain the variability in clinical outcomes. Recent data suggest that cardiovascular morbidity is increased in CMML and contributes to reduced survival. Clonal hematopoiesis of indeterminate potential (CHIP), the presence of mutated blood cells in hematologically normal individuals, is a precursor of age-related myeloid neoplasms and associated with increased cardiovascular risk. To isolate CMML-specific alterations from those related to aging, we performed RNA sequencing and DNA methylation profiling on purified monocytes from CMML patients and from age-matched (old) and young healthy controls. We found that the transcriptional signature of CMML monocytes is highly proinflammatory, with upregulation of multiple inflammatory pathways, including tumor necrosis factor and interleukin (IL)-6 and -17 signaling, whereas age per se does not significantly contribute to this pattern. We observed no consistent correlations between aberrant gene expression and CpG island methylation, suggesting that proinflammatory signaling in CMML monocytes is governed by multiple and complex regulatory mechanisms. We propose that proinflammatory monocytes contribute to cardiovascular morbidity in CMML patients and promote progression by selection of mutated cell clones. Our data raise questions of whether asymptomatic patients with CMML benefit from monocyte-depleting or anti-inflammatory therapies.

Human sperm-associated antigen 4 as a potential biomarker of glioblastoma progression and prognosis

Glioblastoma (GBM) is a highly lethal brain tumor, refractory to current therapies. Sperm-associated antigen 4 (SPAG4) is a novel cancer marker with unclear roles in GBM progression. This study aimed to explore the specific effects of SPAG4 on the pathogenesis of GBM. We first investigated the expression level and prognostic power of SPAG4 in patients with GBM using The Cancer Genome Atlas cohort, and then SPAG4 knockdown by RNA interference was performed to reveal the effects of SPAG4 on GBM cells. mRNA and protein expression levels were determined by real-time PCR and western blot. MTT assay was used to examine cell proliferation, and a wound healing assay was performed to detect cell migration. SPAG4 was significantly overexpressed in patients with GBM, and high expression of SPAG4 was associated with a poor prognosis. Silencing of SPAG4 significantly suppressed the proliferation and migration of GBM cells. Meanwhile, decreased expression and phosphorylation of MEK and ERK were identified after SPAG4 knockdown, suggesting that SPAG4 might regulate GBM progression by activating MEK/ERK signaling pathway. Our study revealed that SPAG4 was identified as a cancer biomarker for GBM and might be a promising target for clinical diagnosis and intervention of GBM.

Transcriptional Regulation of Acyl-CoA:Glycerol-sn-3-Phosphate Acyltransferases

Acyl-CoA:glycerol-sn-3-phosphate acyltransferase (GPAT) is an enzyme responsible for the rate-limiting step in the synthesis of glycerophospholipids and triacylglycerol (TAG). The enzymes of mammalian species are classified into four isoforms; GPAT1 and GPAT2 are localized in the mitochondrial outer membrane, whereas GPAT3 and GPAT4 are localized in the endoplasmic reticulum membrane. The activity of each enzyme expressed is associated with physiological and pathological functions. The transcriptional regulation is well known, particularly in GPAT1. GPAT1 mRNA expression is mainly regulated by the binding of the transcriptional factor SREBP-1c to the specific element (the sterol regulatory element) flanking the GPAT1 promoter. The TAG level is controlled by the insulin-induced transcriptional expression of GPAT1, which occupies most of the GPAT activity in the liver. The transcriptional regulation of the other three GPAT isoforms remains undetermined in detail. It is predicted that retinoic acid serves as a transcription factor in the GPAT2 promoter. PPARγ (peroxisome proliferator-activated receptor γ) increases the mRNA expression of GPAT3, which is associated with TAG synthesis in adipose tissues. Although GPAT has been considered to be a key enzyme in the production of TAG, unexpected functions have recently been reported, particularly in GPAT2. It is likely that GPAT2 is associated with tumorigenesis and normal spermatogenesis. In this review, the physiological and pathophysiological roles of the four GPAT isoforms are described, alongside the transcriptional regulation of these enzymes.

TMEFF1 overexpression and its mechanism for tumor promotion in ovarian cancer

Background

Transmembrane protein with epidermal growth factor-like and two follistatin-like domains 1 (TMEFF1) has an anticarcinogenic effect in brain tumors. However, little is known about the role of TMEFF1 in epithelial ovarian cancer (EOC).

Materials and methods

TMEFF1 expression in EOC was detected by immunohistochemistry; its relationship with clinical pathological parameters and its influence on prognosis were analyzed. The MTT, scratch, Transwell assays, and flow cytometry were used to assess the malignant behavior of ovarian cancer cell. Changes in node proteins in MAPK and PI3K/AKT signaling pathways and the expression of epithelial–mesenchymal transformation markers were measured by Western blot. The regulatory effect of p53 on TMEFF1 was verified by chromatin immunoprecipitation (ChIP) assay and Western blot.

Results

TMEFF1 expression was higher in the EOC group than in the borderline and benign tumor groups and normal ovary group; its high expression was significantly related to International Federation of Gynecology and Obstetrics stage (P=0.024) and independently predicted shorter overall survival (P<0.01). TMEFF1 overexpression in ovarian cancer cells induced increased cellular proliferation, migration, and invasion but reduced apoptosis. In addition, the percentage of phosphorylated node proteins in MAPK and PI3K/AKT signaling pathways increased significantly. The expression of E-cadherin decreased but that of vimentin and N-cadherin increased. After the addition of MAPK (PD98059) and PI3K (GDC-0941) pathway inhibitors, ovarian cancer cells overexpressing TMEFF1 showed suppressed malignant behavior. TMEFF1 protein expression in an ovarian cancer cell lines (CAOV3 and ES-2) was downregulated after the inhibition of TP53. The transcription factor, p53, bound the promoter region of the TMEFF1 gene according to ChIP.

Conclusion

TMEFF1 is a carcinogenic gene in ovarian cancer and can be regulated by p53 transcription. Through MAPK and PI3K/AKT signaling pathways, TMEFF1 promotes the malignant behavior in EOC. Therefore, TMEFF1 may be considered as a potential therapeutic target for ovarian cancer.

A Self-Training Subspace Clustering Algorithm under Low-Rank Representation for Cancer Classification on Gene Expression Data

Accurate identification of the cancer types is essential to cancer diagnoses and treatments. Since cancer tissue and normal tissue have different gene expression, gene expression data can be used as an efficient feature source for cancer classification. However, accurate cancer classification directly using original gene expression profiles remains challenging due to the intrinsic high-dimension feature and the small size of the data samples. We proposed a new self-training subspace clustering algorithm under low-rank representation, called SSC-LRR, for cancer classification on gene expression data. Low-rank representation (LRR) is first applied to extract discriminative features from the high-dimensional gene expression data; the self-training subspace clustering (SSC) method is then used to generate the cancer classification predictions. The SSC-LRR was tested on two separate benchmark datasets in control with four state-of-the-art classification methods. It generated cancer classification predictions with an overall accuracy 89.7 percent and a general correlation 0.920, which are 18.9 and 24.4 percent higher than that of the best control method respectively. In addition, several genes (RNF114, HLA-DRB5, USP9Y, and PTPN20) were identified by SSC-LRR as new cancer identifiers that deserve further clinical investigation. Overall, the study demonstrated a new sensitive avenue to recognize cancer classifications from large-scale gene expression data.

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.

Targeting Tumor Initiating Cells through Inhibition of Cancer Testis Antigens and Notch Signaling: A Hypothesis

Tumor initiating cells (TICs) differ from normal stem cells (SCs) in their ability to initiate tumorigenesis, invasive growth, metastasis and the acquisition of chemo and/or radio-resistance. Over the past years, several studies have indicated the potential role of the Notch system as a key regulator of cellular stemness and tumor development. Furthermore, the expression of cancer testis antigens (CTA) in TICs, and their role in SC differentiation and biology, has become an important area of investigation. Here, we propose a model in which CTA expression and Notch signaling interacts to maintain the sustainability of self-replicating tumor populations, ultimately leading to the development of metastasis, drug resistance and cancer progression. We hypothesize that Notch-CTA interactions in TICs offer a novel opportunity for meaningful therapeutic interventions in cancer.

Immunotherapy in Multiple Myeloma Using Cancer-Testis Antigens

Context:

Multiple myeloma (MM) is a B-cell malignancy characterized by monoclonal expansion of abnormal plasma cells in the bone marrow. It accounts for 10% of hematological malignancies. Although patients respond to a wide range of anticancer modalities, relapse occurs in a significant number of the cases. Immunotherapeutic approaches have been evolved to tackle this problem. Cancer-testis antigens CTAs as a group of tumor-associated antigens are appropriate targets for cancer immunotherapy as they have restricted expression pattern in normal tissues except for testis which is an immune-privileged site. Expression of these antigens has been assessed in different malignancies including MM.

Evidence Acquisition:

We performed a computerized search of the MEDLINE/PubMed databases with key words: multiple myeloma, cancer-testis antigen, and cancer stem cell and immunotherapy.

Results:

Several CTAs including NY-ESO-1, MAGE and GAGE family have been shown to be expressed in MM patients. Cellular and humoral immune responses against these antigens have been detected in MM patients.

Conclusions:

The frequent and high expression level of CTAs in MM patients shows that these antigens can be applied as cancer biomarkers as well as targets for immunotherapy in these patients.

Glycerol-3-phosphate acyltranferase-2 behaves as a cancer testis gene and promotes growth and tumorigenicity of the breast cancer MDA-MB-231 cell line

The de novo synthesis of glycerolipids in mammalian cells begins with the acylation of glycerol-3-phosphate, catalyzed by glycerol-3-phosphate acyltransferase (GPAT). GPAT2 is a mitochondrial isoform primarily expressed in testis under physiological conditions. Because it is aberrantly expressed in multiple myeloma, it has been proposed as a novel cancer testis gene. Using a bioinformatics approach, we found that GPAT2 is highly expressed in melanoma, lung, prostate and breast cancer, and we validated GPAT2 expression at the protein level in breast cancer by immunohistochemistry. In this case GPAT2 expression correlated with a higher histological grade. 5-Aza-2′ deoxycytidine treatment of human cells lines induced GPAT2 expression suggesting epigenetic regulation of gene expression. In order to evaluate the contribution of GPAT2 to the tumor phenotype, we silenced its expression in MDA-MB-231 cells. GPAT2 knockdown diminished cell proliferation, anchorage independent growth, migration and tumorigenicity, and increased staurosporine-induced apoptosis. In contrast, GPAT2 over-expression increased cell proliferation rate and resistance to staurosporine-induced apoptosis. To understand the functional role of GPAT2, we performed a co-expression analysis in mouse and human testis and found a significant association with semantic terms involved in cell cycle, DNA integrity maintenance, piRNA biogenesis and epigenetic regulation. Overall, these results indicate the GPAT2 would be directly associated with the control of cell proliferation. In conclusion, we confirm GPAT2 as a cancer testis gene and that its expression contributes to the tumor phenotype of MDA-MB-231 cells.

Prioritizing Potentially Druggable Mutations with dGene: An Annotation Tool for Cancer Genome Sequencing Data

A major goal of cancer genome sequencing is to identify mutations or other somatic alterations that can be targeted by selective and specific drugs. dGene is an annotation tool designed to rapidly identify genes belonging to one of ten druggable classes that are frequently targeted in cancer drug development. These classes were comprehensively populated by combining and manually curating data from multiple specialized and general databases. dGene was used by The Cancer Genome Atlas squamous cell lung cancer project, and here we further demonstrate its utility using recently released breast cancer genome sequencing data. dGene is designed to be usable by any cancer researcher without the need for support from a bioinformatics specialist. A full description of dGene and options for its implementation are provided here.

Sperm-associated antigen 4, a novel hypoxia-inducible factor 1 target, regulates cytokinesis, and its expression correlates with the prognosis of renal cell carcinoma

Hypoxia plays a crucial role in many pathophysiological conditions, including cancer biology, and hypoxia-inducible factor (HIF) regulates transcriptional responses under hypoxia. To elucidate the cellular responses to hypoxia, we performed chromatin immunoprecipitation with deep sequencing in combination with microarray analysis and identified HIF-1 targets. We focused on one of the novel targets, sperm-associated antigen 4 (SPAG4), whose function was unknown. SPAG4, an HIF-1-specific target, is up-regulated in various cultured cells under hypoxia. Examination of SPAG4 expression using a tissue microarray consisting of 190 human renal cell carcinoma (RCC) samples revealed that SPAG4 is an independent prognostic factor of cancer-specific mortality. Live-cell imaging revealed localization of SPAG4 at the intercellular bridge in telophase. We also studied cells in which SPAG4 was knocked down. Hypoxia enhances tetraploidy, which disturbs cell proliferation, and knockdown of SPAG4 increased tetraploid formation and decreased cell proliferation under both normoxic and hypoxic conditions. Studies using deletion mutants of SPAG4 also suggested the involvement of SPAG4 in cytokinesis. Microarray analysis confirmed dysregulation of cytokinesis-related genes by knockdown of SPAG4. In conclusion, SPAG4 is an independent prognostic factor in RCC and plays a crucial role in cytokinesis to defend against hypoxia-induced tetraploid formation. This defensive mechanism may promote survival of cancer cells under hypoxic conditions, thus leading to poor prognosis.

Gene expression profiling in multiple myeloma--reporting of entities, risk, and targets in clinical routine

PURPOSE

Multiple myeloma is an incurable malignant plasma cell disease characterized by survival ranging from several months to more than 15 years. Assessment of risk and underlying molecular heterogeneity can be excellently done by gene expression profiling (GEP), but its way into clinical routine is hampered by the lack of an appropriate reporting tool and the integration with other prognostic factors into a single "meta" risk stratification.

EXPERIMENTAL DESIGN

The GEP-report (GEP-R) was built as an open-source software developed in R for gene expression reporting in clinical practice using Affymetrix microarrays. GEP-R processes new samples by applying a documentation-by-value strategy to the raw data to be able to assign thresholds and grouping algorithms defined on a reference cohort of 262 patients with multiple myeloma. Furthermore, we integrated expression-based and conventional prognostic factors within one risk stratification (HM-metascore).

RESULTS

The GEP-R comprises (i) quality control, (ii) sample identity control, (iii) biologic classification, (iv) risk stratification, and (v) assessment of target genes. The resulting HM-metascore is defined as the sum over the weighted factors gene expression-based risk-assessment (UAMS-, IFM-score), proliferation, International Staging System (ISS) stage, t(4;14), and expression of prognostic target genes (AURKA, IGF1R) for which clinical grade inhibitors exist. The HM-score delineates three significantly different groups of 13.1%, 72.1%, and 14.7% of patients with a 6-year survival rate of 89.3%, 60.6%, and 18.6%, respectively.

CONCLUSION

GEP reporting allows prospective assessment of risk and target gene expression and integration of current prognostic factors in clinical routine, being customizable about novel parameters or other cancer entities.

Cancer testis antigens in newly diagnosed and relapse multiple myeloma: prognostic markers and potential targets for immunotherapy

BACKGROUND

In multiple myeloma, expression of cancer testis antigens may provide prognostic markers and potential targets for immunotherapy. Expression at relapse has not yet been evaluated for a large panel of cancer testis antigens which can be classified by varying expression in normal tissue: restricted to testis, expressed in testis and brain and not restricted but selectively expressed in testis.

DESIGN AND METHODS

Evaluation of cancer testis antigen expression was made in newly diagnosed multiple myeloma cases (HOVON-65/GMMG-HD4 trial; n = 320) and in relapse cases (APEX, SUMMIT, CREST trials; n = 264). Presence of expression using Affymetrix GeneChips was determined for 123 cancer testis antigens. Of these 87 had a frequency of more than 5% in the newly diagnosed and relapsed patients, and were evaluated in detail.

RESULTS

Tissue restriction was known for 58 out of 87 cancer testis antigens. A significantly lower frequency of presence calls in the relapsed compared to newly diagnosed cases was found for 3 out of 13 testis restricted genes, 2 out of 7 testis/brain restricted genes, and 17 out of 38 testis selective genes. MAGEC1, MAGEB2 and SSX1 were the most frequent testis-restricted cancer testis antigens in both data sets. Multivariate analysis demonstrated that presence of MAGEA6 and CDCA1 were clearly associated with shorter progression free survival, and presence of MAGEA9 with shorter overall survival in the set of newly diagnosed cases. In the set of relapse cases, presence of CTAG2 was associated with shorter progression free survival and presence of SSX1 with shorter overall survival.

CONCLUSIONS

Relapsed multiple myeloma reveals extensive cancer testis antigen expression. Cancer testis antigens are confirmed as useful prognostic markers in newly diagnosed multiple myeloma patients and in relapsed multiple myeloma patients. The HOVON-65/GMMG-HD4 trial is registered under Dutch trial register n. NTR-213. CREST, SUMMIT and APEX trials were registered under ns. M34100-024, M34100-025 and NCT00049478/NCT00048230, respectively.

Successful cross-presentation of allogeneic myeloma cells by autologous alpha-type 1-polarized dendritic cells as an effective tumor antigen in myeloma patients with matched monoclonal immunoglobulins

For wide application of a dendritic cell (DC) vaccination in myeloma patients, easily available tumor antigens should be developed. We investigated the feasibility of cellular immunotherapy using autologous alpha-type 1-polarized dendritic cells (αDC1s) loaded with apoptotic allogeneic myeloma cells, which could generate myeloma-specific cytotoxic T lymphocytes (CTLs) against autologous myeloma cells in myeloma patients. Monocyte-derived DCs were matured by adding the αDC1-polarizing cocktail (TNFα/IL-1β/IFN-α/IFN-γ/poly-I:C) and loaded with apoptotic allogeneic CD138(+) myeloma cells from other patients with matched monoclonal immunoglobulins as a tumor antigen. There were no differences in the phenotypic expression between αDC1s loaded with apoptotic autologous and allogeneic myeloma cells. Autologous αDC1s effectively took up apoptotic allogeneic myeloma cells from other patients with matched subtype. Myeloma-specific CTLs against autologous target cells were successfully induced by αDC1s loaded with allogeneic tumor antigen. The cross-presentation of apoptotic allogeneic myeloma cells to αDC1s could generate CTL responses between myeloma patients with individual matched monoclonal immunoglobulins. There was no difference in CTL responses between αDC1s loaded with autologous tumor antigen and allogeneic tumor antigen against targeting patient's myeloma cells. Our data indicate that autologous DCs loaded with allogeneic myeloma cells with matched immunoglobulin can generate potent myeloma-specific CTL responses against autologous myeloma cells and can be a highly feasible and effective method for cellular immunotherapy in myeloma patients.

Molecular pathogenesis of multiple myeloma: chromosomal aberrations, changes in gene expression, cytokine networks, and the bone marrow microenvironment

This chapter focuses on two aspects of myeloma pathogenesis: (1) chromosomal aberrations and resulting changes in gene and protein expression with a special focus on growth and survival factors of malignant (and normal) plasma cells and (2) the remodeling of the bone marrow microenvironment induced by accumulating myeloma cells. We begin this chapter with a discussion of normal plasma cell generation, their survival, and a novel class of inhibitory factors. This is crucial for the understanding of multiple myeloma, as several abilities attributed to malignant plasma cells are already present in their normal counterpart, especially the production of survival factors and interaction with the bone marrow microenvironment (niche). The chapter closes with a new model of pathogenesis of myeloma.

DNA vaccines to target the cancer testis antigen PASD1 in human multiple myeloma

We previously described PASD1 as a new cancer testis antigen in multiple myeloma (MM) that is retained post-therapy, suggesting the use of vaccination strategies to induce anti-PASD1 immunity in a setting of minimal residual disease. We have focused on DNA fusion gene vaccines, coupling fragment C domain (DOM) of tetanus toxin with PASD1 sequence, and examined efficacy in Human Leukocyte Antigen (HLA)-A2 (HHD) transgenic mice using a human MM cell line expressing PASD1 protein and chimeric HLA-A2 class I molecules as target. DNA vaccines encoded two HLA-A2-restricted epitopes (p.DOM-PASD1(1), p.DOM-PASD1(2)) and full-length PASD1 (p.DOM-PASD1FL). p.DOM-PASD1(1) proved superior to p.DOM-PASD1(2) in generating T-cell responses in HHD mice, able to lyse the chimeric murine RMA-HHD cells. Boosting by electroporation significantly enhanced p.DOM-PASD1(1). Only p.DOM-PASD1(1) induced cytotoxic T-lymphocytes (CTLs) were able to lyse human MM target cells expressing endogenous antigen. The p.DOM-PASD1FL vaccine predominantly induced strong PASD1(1) over PASD1(2) T-cell immune responses, indicative of immunodominance. Importantly, p.DOM-PASD1FL generated immune-mediating killing of native chimeric MM cells, in the absence of exogenous added peptide, implicating PASD1(1) specific CTLs. These data demonstrate that PASD1-derived epitopes are both efficiently and selectively processed and presented by native human MM cells. Notably, they permit the use of PASD1-encoding DNA vaccine therapy in a clinical setting.

Alpha-type 1-polarized dendritic cells loaded with apoptotic allogeneic myeloma cell line induce strong CTL responses against autologous myeloma cells

To induce a potent cytotoxic T lymphocyte (CTL) response, various tumor antigens should be loaded onto dendritic cells (DCs). In multiple myeloma (MM), it is difficult to obtain a sufficient number of autologous tumor cells as a source of tumor antigens in the clinical setting. We investigated the feasibility of immunotherapy in patients with MM, using myeloma-specific CTLs generated in vitro by alpha-type 1-polarized DCs (alphaDC1s) loaded with the ultraviolet B-irradiated allogeneic myeloma cell line, ARH77. alphaDC1s significantly increased the expression of several costimulatory molecules without differences in loading with tumor antigens. alphaDC1s showed a high production of interleukin-12 during maturation and after subsequent stimulation with CD40L but were not significantly affected by loading tumor antigens. Myeloma-specific CTLs against autologous myeloma cells from MM patients were induced by alphaDC1s pulsed with apoptotic ARH77 cells. Our data indicate that autologous DCs loaded with an allogeneic myeloma cell line can generate potent myeloma-specific CTL responses against autologous myeloma cells and might provide a practical method for cellular immunotherapy in patients with MM.