Cancer-testis antigen MAGEC2 promotes proliferation and resistance to apoptosis in Multiple Myeloma.

Cancer-testis antigens belonging to the MAGE family of genes, such as MAGEC2, are commonly and specifically expressed in Multiple Myeloma (MM) and are associated with a more aggressive clinical course and chemotherapy resistance. MAGEC2 is thought to be an excellent candidate for cancer immunotherapy; however, the biological role of MAGEC2 in MM has remained unclear. We investigated the biological role of MAGEC2 in myeloma cells determining the effect of MAGEC2 knockdown on proliferation and apoptosis. Loss of MAGEC2 resulted in reduced proliferation, viability, and anchorage-independent growth of myeloma cells irrespective of the functional status of TP53 (p53). The anti-proliferative effect of MAGEC2 silencing was due to a decrease of cells in the S phase, cell cycle delay at both G0/G1 and/or G2/M, and an increase in the sub-G0/G1 diploid population related to apoptotic cell death. Importantly, overexpression of short hairpin (sh)RNA-refractory MAGEC2 rescued the anti-proliferative effect of mRNA knockdown and protected cells from apoptotic cell death. Our findings support a TP53-independent role of MAGEC2 in promoting the survival of myeloma cells suggesting that MAGEC2-specific immunotherapies have the potential to eradicate the most malignant cells within the myeloma tumour bulk leading to durable clinical responses.

Cancer-testis antigen SLLP1 represents a promising target for the immunotherapy of multiple myeloma.

BACKGROUND: Most patients with multiple myeloma (MM) will relapse after an initial response and eventually succumb to their disease. This is due to the persistence of chemotherapy-resistant tumor cells in the patients' bone marrow (BM) and immunotherapeutic approaches could contribute to eradicating these remaining cells. We evaluated SLLP1 as a potential immunotherapeutic target for MM. METHODS: We determined SLLP1 expression in myeloma cell lines and 394 BM samples from myeloma patients (n = 177) and BM samples from healthy donors (n = 11). 896 blood samples and 64 BM samples from myeloma patients (n = 263) and blood from healthy donors (n = 112) were analyzed for anti-SLLP1 antibodies. Seropositive patients were evaluated regarding SLLP1-specific T cells. RESULTS: Most cell lines showed SLLP1 RNA and protein expression while it was absent from normal BM. Of 177 patients 41% evidenced SLLP1 expression at least once during the course of their disease and 44% of newly diagnosed patients were SLLP1-positive. Expression of SLLP1 was associated with adverse cytogenetics and with negative prognostic factors including the patient's age, number of BM-infiltrating plasma cells, serum albumin, ß2-microglobulin, creatinine, and hemoglobin. Among patients treated with allogeneic stem cell transplantation those with SLLP1 expression showed a trend towards a reduced overall survival. Spontaneous anti-SLLP humoral immunity was detectable in 9.5% of patients but none of the seropositive patients evidenced SLLP1-specific T cells. However, antigen-specific T cells could readily be induced in vitro after stimulation with SLLP1. CONCLUSIONS: SLLP1 represents a promising target for the immunotherapy of MM, in particular for the adoptive transfer of T cell receptor-transduced T cells.

Challenges and solutions to system-wide use of precision oncology as the standard of care paradigm.

The personalised oncology paradigm remains challenging to deliver despite technological advances in genomics-based identification of actionable variants combined with the increasing focus of drug development on these specific targets. To ensure we continue to build concerted momentum to improve outcomes across all cancer types, financial, technological and operational barriers need to be addressed. For example, complete integration and certification of the 'molecular tumour board' into 'standard of care' ensures a unified clinical decision pathway that both counteracts fragmentation and is the cornerstone of evidence-based delivery inside and outside of a research setting. Generally, integrated delivery has been restricted to specific (common) cancer types either within major cancer centres or small regional networks. Here, we focus on solutions in real-world integration of genomics, pathology, surgery, oncological treatments, data from clinical source systems and analysis of whole-body imaging as digital data that can facilitate cost-effectiveness analysis, clinical trial recruitment, and outcome assessment. This urgent imperative for cancer also extends across the early diagnosis and adjuvant treatment interventions, individualised cancer vaccines, immune cell therapies, personalised synthetic lethal therapeutics and cancer screening and prevention. Oncology care systems worldwide require proactive step-changes in solutions that include inter-operative digital working that can solve patient centred challenges to ensure inclusive, quality, sustainable, fair and cost-effective adoption and efficient delivery. Here we highlight workforce, technical, clinical, regulatory and economic challenges that prevent the implementation of precision oncology at scale, and offer a systematic roadmap of integrated solutions for standard of care based on minimal essential digital tools. These include unified decision support tools, quality control, data flows within an ethical and legal data framework, training and certification, monitoring and feedback. Bridging the technical, operational, regulatory and economic gaps demands the joint actions from public and industry stakeholders across national and global boundaries.

Longitudinal analysis of tetanus- and influenza-specific IgG antibodies in myeloma patients.

BACKGROUND: Multiple myeloma (MM) and its therapies may induce a severely compromised humoral immunity. We have performed a longitudinal analysis of IgG-antibody responses against influenza virus (FLU) and tetanus toxoid (TT) as surrogate markers for the B cell-mediated immunity in MM patients. METHODS: 1094 serum samples of 190 MM patients and samples from 100 healthy donors were analyzed by ELISA for FLU- and TT-specific antibodies. RESULTS: MM patients evidenced lower levels of FLU- and TT-specific antibodies than healthy controls (P < 0.001). Immunoreactivity decreased with progressing disease and worsening clinical status. Levels of FLU- and TT-specific antibodies increased shortly (0-6 months) after alloSCT (P < 0.001), a time-period during which intravenous immunoglobulin (IVIG) is routinely applied. Thereafter, antibody concentrations declined and remained suppressed for 3 years in the case of FLU-specific and for more than 5 years in the case of TT-specific antibodies. CONCLUSIONS: We found that MM is associated with a profound disease- and therapy-related immunosuppression, which is compensated for a few months after alloSCT, most likely by application of IVIG. This and the differences regarding the recovery of anti-FLU and anti-TT antibody titers during the following years need to be taken into account for optimizing IVIG application and immunization after alloSCT.

Surface molecule CD229 as a novel target for the diagnosis and treatment of multiple myeloma.

BACKGROUND: To date, multiple myeloma remains an incurable malignancy due to the persistence of minimal residual disease in the bone marrow. In this setting, monoclonal antibodies against myeloma-specific cell surface antigens represent a promising therapeutic approach, which is however hampered by a lack of appropriate target structures expressed across all pathogenic myeloma cell populations. We, therefore, investigated functionally relevant immunoreceptors specifically associated with myeloma cells as well as their clonogenic precursors. DESIGN AND METHODS: Potential target proteins were identified using antibody arrays against phosphorylated immunoreceptors with lysates from myeloma cell lines. CD229 expression was confirmed in primary myeloma cells by reverse transcriptase polymerase chain reaction, western blot, fluorescence-activated cell sorting, and immunohistochemistry. Apoptosis, clonogenic growth, and sensitivity to chemotherapy were determined following short-interfering RNA-mediated downregulation of CD229. Antibody-dependent cellular and complement-dependent cytotoxicity were analyzed using a monoclonal antibody against CD229 to demonstrate the antigen's immunotherapeutic potential. RESULTS: Our screening assay identified CD229 as the most strongly over-expressed/phosphorylated immunoreceptor in myeloma cell lines. Over-expression was further demonstrated in the CD138-negative population, which has been suggested to represent myeloma precursors, as well as on primary tumor cells from myeloma patients. Accordingly, CD229 staining of patients' bone marrow samples enabled the identification of myeloma cells by flow cytometry and immunohistochemistry. Down-regulation of CD229 led to a decreased number of viable myeloma cells and clonal myeloma colonies, and enhanced the anti-tumor activity of conventional chemotherapeutics. Targeting CD229 with a monoclonal antibody resulted in complement- and cell-mediated lysis of myeloma cells. CONCLUSIONS: Our results demonstrate that the immunoreceptor CD229 is specifically over-expressed on myeloma cells including their clonogenic precursors and contributes to their malignant phenotype. Monoclonal antibodies against this protein may represent a promising diagnostic and immunotherapeutic instrument in this disease.

Cancer-testis antigen expression and its epigenetic modulation in acute myeloid leukemia.

Cancer-testis antigens (CTA) represent attractive targets for tumor immunotherapy. However, a broad picture of CTA expression in acute myeloid leukemia (AML) is missing. CTA expression was analyzed in normal bone marrow (BM) as well as in AML cell lines before and after treatment with demethylating agents and/or histone acetylase inhibitors. Presence of selected CTA with a strictly tumor-restricted expression was then determined in samples of patients with AML before and after demethylating therapy. Screening AML cell lines for the expression of 20 CTA, we identified six genes (MAGE-A3, PRAME, ROPN1, SCP-1, SLLP1, and SPO11) with an AML-restricted expression. Analyzing the expression of these CTA in blast-containing samples from AML patients (N = 64), we found all samples to be negative for MAGE-A3 and SPO11 while a minority of patients expressed ROPN1 (1.6%), SCP-1 (3.1%), or SLLP1 (9.4%). The only CTA expressed in substantial proportion of patients (53.1%) was PRAME. Following demethylating treatment with 5'-aza-2'-deoxycytidine, we observed an increased or de novo expression of CTA, in particular of SSX-2, in AML cell lines. In AML patients, we detected increased expression of PRAME and induction of SSX-2 after demethylating therapy with 5-azacytidine. With the exception of PRAME, CTA are mostly absent from AML blasts. However, demethylating treatment induces strong expression of CTA, particularly of SSX-2, in vitro and in vivo. Therefore, we propose that CTA-specific immunotherapy for AML should preferentially target PRAME and/or should be combined with the application of demethylating agents opening the perspective for alternative targets like CTA SSX-2.

Patients with multiple myeloma develop SOX2-specific autoantibodies after allogeneic stem cell transplantation.

The occurrence of SOX2-specific autoantibodies seems to be associated with an improved prognosis in patients with monoclonal gammopathy of undetermined significance (MGUS). However, it is unclear if SOX2-specific antibodies also develop in established multiple myeloma (MM). Screening 1094 peripheral blood (PB) sera from 196 MM patients and 100 PB sera from healthy donors, we detected SOX2-specific autoantibodies in 7.7% and 2.0% of patients and donors, respectively. We identified SOX2(211-230) as an immunodominant antibody-epitope within the full protein sequence. SOX2 antigen was expressed in most healthy tissues and its expression did not correlate with the number of BM-resident plasma cells. Accordingly, anti-SOX2 immunity was not related to SOX2 expression levels or tumor burden in the patients' BM. The only clinical factor predicting the development of anti-SOX2 immunity was application of allogeneic stem cell transplantation (alloSCT). Anti-SOX2 antibodies occurred more frequently in patients who had received alloSCT (n = 74). Moreover, most SOX2-seropositive patients had only developed antibodies after alloSCT. This finding indicates that alloSCT is able to break tolerance towards this commonly expressed antigen. The questions whether SOX2-specific autoantibodies merely represent an epiphenomenon, are related to graft-versus-host effects or participate in the immune control of myeloma needs to be answered in prospective studies.

NY-ESO-1 expression and immunogenicity in prostate cancer patients.

BACKGROUND: Prostate cancer is the second leading cause of men cancer-related death. Cancer immunotherapy has been investigated as a treatment which might be instituted at the point of detection of androgen-independent metastatic disease. AIM: to investigate the expression and humoral response against NYESO-1 in patients with prostate cancer (PC) and to analyze the relationship between expression of NY-ESO-1 and clinicopathological features. METHODS: NY-ESO-1 mRNA in surgically resected PC and benign prostatic hyperplasia (BPH) were examined by reverse transcriptionpolymerase chain reaction. The antibody response to NY-ESO-1 was examined by enzyme-linked Elisa assay using recombinant NYESO-1 protein. RESULTS: NY-ESO-1 mRNA was detected in 9 of 23 (39%) PC patients. Antibodies against NY-ESO-1 protein were detected in 12 of 23 (52%) sera of PC patients and in 5 of 9 (55%) of NY-ESO-1 expressing tumors. However, no mRNA copy or NY-ESO-1 antibodies were detected in all BPH patients tested. CONCLUSION: The present study has demonstrated the expression of NY-ESO-1mRNA in prostate Cancer patients and NY-ESO-1 antibody production. Our data suggest that NY-ESO-1 could be used as a tumor marker and constitute a good candidate for vaccine-based immunotherapy for hormonal resistant prostate cancer patients.

Cancer-testis antigens MAGE-C1/CT7 and MAGE-A3 promote the survival of multiple myeloma cells.

BACKGROUND: Multiple myeloma is a life-threatening disease and despite the introduction of stem cell transplantation and novel agents such as thalidomide, lenalidomide, and bortezomib most patients will relapse and develop chemoresistant disease. Therefore, alternative therapeutic modes for myeloma are needed and cancer-testis antigens such as MAGE-C1/CT7 and MAGE-A3 have been suggested to represent a class of tumor-specific proteins particularly suited for targeted immunotherapies. Surprisingly, the biological role of cancer-testis genes in myeloma remains poorly understood. DESIGN AND METHODS: We performed the first investigation of the function of two cancer-testis antigens most commonly expressed in myeloma, MAGE-C1/CT7 and MAGE-A3, using an RNA interference-based gene silencing model in myeloma cell lines. Functional assays were used to determine changes in proliferation, cell adhesion, chemosensitivity, colony formation, and apoptosis resulting from gene-specific silencing. RESULTS: We show that the investigated genes are not involved in regulating cell proliferation or adhesion; however, they play an important role in promoting the survival of myeloma cells. Accordingly, knock-down of MAGE-C1/CT7 and MAGE-A3 led to the induction of apoptosis in the malignant plasma cells and, importantly, both genes were also essential for the survival of clonogenic myeloma precursors. Finally, silencing of cancer-testis genes further improved the response of myeloma cells to conventional therapies. CONCLUSIONS: Cancer-testis antigens such as MAGE-C1/CT7 and MAGE-A3 play an important role in promoting the survival of myeloma cells and clonogenic precursors by reducing the rate of spontaneous and chemotherapy-induced apoptosis and might, therefore, represent attractive targets for novel myeloma-specific therapies.

The trifunctional antibody catumaxomab amplifies and shapes tumor-specific immunity when applied to gastric cancer patients in the adjuvant setting.

BACKGROUND: Patients with gastric cancer benefit from perioperative chemotherapy, however, treatment is toxic and many patients will relapse. The trifunctional antibody catumaxomab targets EpCAM on tumor cells, CD3 on T cells, and the Fcγ-receptor of antigen-presenting cells. While in Europe catumaxomab is approved for treating malignant ascites, it has not been investigated in the perioperative setting and its exact immunological mode of action is unclear. METHODS: In our study, gastric cancer patients received neoadjuvant platinum-based chemotherapy, one intraoperative application of catumaxomab, and 4 postoperative doses of intraperitoneal catumaxomab. Immunomonitoring was performed in 6 patients before surgery, after completion of catumaxomab treatment, and one month later. RESULTS: Intraperitoneal application of catumaxomab caused an increased expression of activation markers on the patients' T cells. This was accompanied by a transient decrease in numbers of CXCR3(+) effector T cells with a T-helper (Th)-1 phenotype in the peripheral blood. All patients evidenced pre-existing EpCAM-specific CD4(+) and/or CD8(+) T cells. While these cells transiently disappeared from the blood stream after intraperitoneal application of catumaxomab, we detected increased numbers of peripheral EpCAM-specific cells and a modified EpCAM-specific T-cell repertoire 4 weeks after completion of treatment. Finally, catumaxomab also amplified humoral immunity to tumor antigens other than EpCAM. CONCLUSIONS: Our findings suggest that catumaxomab exerts its clinical effects by (1) activating peripheral T cells, (2) redistributing effector T cells from the blood into peripheral tissues, (3) expanding and shaping of the pre-existing EpCAM-specific T-cell repertoire, and (4) spreading of anti-tumor immunity to different tumor antigens.

Role of interleukin 16 in multiple myeloma.

BACKGROUND: Multiple myeloma is a malignancy characterized by the expansion of a plasma cell clone that localizes to the human bone marrow. Myeloma cells and bone marrow stromal cells produce soluble factors that promote the survival and progression of multiple myeloma. Interleukin 16 (IL-16) is involved in regulating the migration and proliferation of normal leukocytes. However, the role of IL-16 in human cancers, including multiple myeloma, is unclear. METHODS: We investigated IL-16 expression in cell lines (n = 10) and in the bone marrow of myeloma patients (n = 62) and healthy bone marrow donors (n = 12) by quantitative reverse transcription-polymerase chain reaction, immunoblot analysis, enzyme-linked immunosorbent assay, flow cytometry, and immunohistochemistry. Transfection of two human multiple myeloma cell lines with small interfering RNAs was used to examine the effect of IL-16 gene silencing on apoptosis by flow cytometry, on proliferation by bromodeoxyuridine incorporation, and on colony formation. Protein neutralization assays were performed by treating multiple myeloma cells with a monoclonal antibody against the carboxyl-terminal fragment of IL-16. All statistical tests were two-sided. RESULTS: IL-16 was strongly overexpressed in the bone marrow of myeloma patients compared with healthy donors. Myeloma cell lines as well as primary tumor cells from myeloma patients constitutively expressed IL-16 and its receptors CD4 and/or CD9 and spontaneously secreted soluble IL-16. Silencing of IL-16 reduced the proliferative activity of myeloma cells by approximately 80% compared with untreated cells (mean relative proliferative activity IL-16 siRNA vs untransfected cells, EJM cells: 20.1%, 95% confidence interval [CI] = 14.3% to 26.0%, P = .03; KMS-12-BM cells: 22.8%, 95% CI = 5.5% to 40.0%, P = .04), and addition of a recombinant carboxyl-terminal IL-16 peptide reversed that effect. A monoclonal antibody directed against IL-16 or its receptors had a comparably strong growth-inhibiting effect on the tumor cells. CONCLUSIONS: IL-16 is an important growth-promoting factor in multiple myeloma and a candidate for novel diagnostic, prognostic, and therapeutic applications for this incurable human malignancy.

An optimized assay for the enumeration of antigen-specific memory B cells in different compartments of the human body.

OBJECT: In the framework of our current study we set out to develop an optimized assay for the quantification of antigen-specific B cells in different compartments of the human body. METHODS: Mononuclear cells (MNC) derived from the peripheral blood, bone marrow (BM), or human tonsils were incubated with different combinations of stimuli. The stimulated cells and culture supernatants were then applied to IgG-ELISPOT and ELISA read-out assays and tetanus toxoid (TT)-specific B cell responses were quantified. RESULTS: We found that a combination of CD40L, CpG, and IL21 was optimal for the induction of TT-specific IgG-producing cells from memory B cell (mBc) precursors. This cocktail of stimuli led to a proliferation-dependent induction of CD19(intermediate)CD38(high)CD138(high)IgD(negative) terminally differentiated plasma cells. Applying our optimized methodology we were also able to quantify mBc specific for cytomegalovirus and influenza virus A. Most importantly, the same method proved useful for the comparison of mBc frequencies between different compartments of the body and, accordingly, we were able to demonstrate that TT-specific mBc preferably reside within tonsillar tissue. CONCLUSION: Here, we optimized an assay for the quantification of antigen-specific B cells in different human tissues demonstrating, for example, that TT-specific mBc preferably reside in human tonsils but not in the BM or the peripheral blood. We suggest that our approach can be used for the enumeration of mBc specific for a wide variety of Ag (microbial, tumor-related, auto-antigens), which will lead to significant improvements regarding our knowledge about the biology of humoral immunity.

The cytokine/chemokine pattern in the bone marrow environment of multiple myeloma patients.

OBJECTIVE: The interaction of multiple myeloma (MM) with its bone marrow (BM) microenvironment is important for the homing pattern, survival, and proliferation of malignant plasma cells. We aimed at answering the question which cytokines, chemokines, and growth factors are typically found in the BM of untreated MM patients as well as in MM patients after allogeneic stem cell transplantation (alloSCT). MATERIALS AND METHODS: We determined the concentrations of 34 cytokines/chemokines in the supernatants of 10 myeloma cell lines, as well as in the plasma derived from BM and peripheral blood samples of 10 newly diagnosed MM patients, 20 MM patients who had received allogeneic stem cell transplantation (alloSCT), and 20 healthy donors. RESULTS: Besides cytokines/chemokines known to be secreted by myeloma cell lines, such as interleukin-1 receptor antagonist (IL-1RA), IL-8, monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1α, MIP-1ß, and MIP-3α, we also detected significant levels of epidermal growth factor (EGF), hepatocyte growth factor (HGF), IL2R, IL-12p40/p70, IL-22, interferon-γ (IFN-γ)-inducible protein 10 (IP-10), monokine induced by IFN-γ (MIG), and regulated on activation normally T-cell expressed and secreted (RANTES) in culture supernatants. The BM environment in MM patients evidenced elevated concentrations of HGF, IL-2R, IL-16, EGF, IL-1RA, IP-10, MCP-1, and monokine induced by IFN-γ. Additionally, in the BM of MM patients post alloSCT, we found selectively elevated concentration of IL-4, IL-6, IL-8, IL-12p40/p70, and eotaxin. Eotaxin levels were particularly high in patients with chronic graft-vs-host disease. CONCLUSIONS: Our study demonstrates characteristic cytokine/chemokine patterns in the BM environment of MM patients before and after alloSCT. Certain factors, such as MIP-1α, MCP-1, HGF, IL-16, IP-10, and eotaxin, might not only be developed into diagnostic instruments and/or predictive biomarkers, but are also potential targets for future myeloma- or graft-vs-host disease-specific therapies.

Expression, epigenetic regulation, and humoral immunogenicity of cancer-testis antigens in chronic myeloid leukemia.

OBJECTIVE: Cancer-testis (CT) antigens represent attractive targets for tumor immunotherapy based on their tumor-restricted expression and immunogenicity. However, a broad picture of the expression of CT antigens and associated humoral immune responses in chronic myeloid leukemia (CML) is still missing. METHODS: We screened CML cell lines and bone marrow (BM) samples from healthy donors by RT-PCR for the expression of 31 CT antigens before and after treatment with epigenetic agents. Expression of tumor-restricted antigens was further examined in 60 CML patients and humoral immune responses against 15 CT antigens were screened by ELISA. RESULTS: In untreated cell lines we detected the expression of 17 CT antigens that were absent from normal BM. Expression of most antigens increased following demethylating treatment with 5'-Aza-2'-Deoxycytidine. In these samples, only PRAME was repeatedly detected and expression correlated with several clinicopathological parameters and decreased overall survival. We further show that a lower frequency of PRAME-positive samples during imatinib treatment was not caused by gene-specific downregulation. Analyzing the patients' antibody responses we found that the vast majority of patients lacked spontaneous immunity against CT antigens including PRAME. CONCLUSIONS: CT antigen expression can be increased by the application of epigenetic agents and the expression of PRAME correlates with clinicopathological parameters and overall survival in patients with CML, but does not lead to humoral immune responses. PRAME-specific immunotherapy might represent a promising approach for the eradication of residual therapy-resistant leukemic cells due to its frequent expression and stability under imatinib treatment.