Sebastian Kobold

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.

Intraperitoneal VEGF Inhibition Using Bevacizumab: A Potential Approach for the Symptomatic Treatment of Malignant Ascites?

Despite overall improvements in oncological care in the palliative setting, symptomatic malignant ascites remains a severe clinical problem. This form of effusion is known to be widely resistant to established modes of systemic therapy. Accordingly, frequent paracentesis often represents the only effective way for symptom relief in patients with advanced cancer. This invasive mode of therapy, however, is often very burdensome for the patient who is already severely distressed by the underlying malignancy. Recently, the trifunctional monoclonal antibody catumaxomab given i.p. has shown symptom relief in patients with ovarian cancer and malignant ascites. On another front, the release of vascular endothelial growth factor (VEGF) by tumor cells has been identified as a main factor promoting the i.p. secretion of fluid. Accordingly, recent evidence suggests that targeting VEGF may have the potential to suspend the ascites production resulting from peritoneal metastasis. Here, we review preclinical and clinical data supporting this hypothesis. We show current evidence suggesting that the i.p. application of the anti-VEGF antibody bevacizumab, which is already in use as an i.v. therapeutic drug for a variety of tumors, might represent an effective way to prevent local fluid accumulation. Because such an effect would result in significant relief for patients, future clinical studies should stringently assess the effectiveness of this targeted therapy for the treatment of malignant i.p. effusions.

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

OBJECTIVEnThe 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).nnnMATERIALS AND METHODSnWe 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.nnnRESULTSnBesides 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-1β, 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.nnnCONCLUSIONSnOur 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.

Prognostic and diagnostic value of spontaneous tumor-related antibodies.

There is an urgent need for earlier diagnosis of malignancies and more stringent monitoring of relapses after antitumor therapy. In addition, new prognostic markers are needed for risk stratification and design of individualized cancer therapies. New diagnostic and prognostic parameters should overcome the impairments of current standards in a cost-effective manner. Serological approaches measuring spontaneous antibody responses against tumor-associated antigens could be of use as diagnostic and prognostic markers and could also be employed to evaluate response to therapy in cancer patients. Autoantibodies have been suggested to be of frequent and specific occurrence in patients with malignancies and to correlate with clinical parameters. Screening the relevant literature on this topic, we suggest that the analysis of single antibody specificities is unlikely to provide sufficient diagnostic and prognostic accuracy. The combined analysis of autoantibodies targeting different antigens, however, may reach high sensitivity and specificity. In addition, screening cancer patients for autoantibodies might identify subgroups with high relapse risk and a worse prognosis. Larger prospective trials should be initiated to identify sets of tumor-associated autoantibodies suited for the use in diagnostic algorithms for cancer detection and followup.

Primary NK/T cell lymphoma nasal type of the stomach with skin involvement: a case report

Since nasal NK/T cell lymphoma and NK/T cell lymphoma nasal type are rare diseases, gastric involvement has seldom been seen. We report a unique case of a patient with a primary NK/T cell lymphoma nasal type of the stomach with skin involvement. The patient had no history of malignant diseases and was diagnosed with hematemesis and intense bleeding from his gastric primary site. Shortly after this event, exanthemic skin lesions appeared with concordant histology to the primary site. Despite chemotherapy, the patient died one month after the first symptomatic appearance of disease.

Abstract 2450: Surface molecule CD229 represents a possible target for the treatment of multiple myeloma

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DCnnBACKGROUND AND OBJECTIVES: The majority of patients with multiple myeloma (MM) will eventually relapse and succumb to their disease even after high dose chemotherapy and autologous stem cell transplantation, possibly due to the persistence of BM-residing myeloma stem cells. Therefore, new treatment strategies incorporating new therapeutic targets - ideally to be expressed by the bulk of end-stage myeloma cells and their dormant progenitors - are needed to improve the outcome of myeloma patients.nnDESIGN AND METHODS: We screened myeloma cell lines for the presence of a large number of immunoreceptors and verified expression of potential target molecules on cell lines and patient samples. The function of the respective proteins was evaluated using gene knockdown and their potential as targets for antibody therapies was investigated using in vitro cytotoxicity assays.nnRESULTS: Of all immunoreceptors analyzed, SLAM family member CD229 showed the strongest expression and was also found on myeloma precursors. Primary myeloma cells of myeloma patients uniformly evidenced CD229 surface expression while the molecule was absent from most healthy human tissues. Flow cytometric analysis of CD229 expression facilitated the detection of myeloma cells in the bone marrow. CD229 seemed to promote the survival of myeloma cells while CD229 silencing increased their susceptibility towards chemotherapy. Importantly, targeting CD229 with a monoclonal antibody resulted in specific lysis of the tumor cells.nnCONCLUSIONS: These results suggest that CD229 might represent an attractive diagnostic and therapeutic target for the treatment of MM.nnNote: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.nnCitation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2450.

Abstract #4172: Expression, epigenetic regulation, and immunogenicity of cancer-testis antigens in chronic myeloid leukemia (CML)

BACKGROUND: Expression of cancer-testis antigens is characteristically restricted to cancer and the human germline and their distinctive immunogenicity renders them attractive targets in immunotherapeutic settings, e.g. in patients with CML showing imatinib-resistance or minimal residual disease. In order to identify potential targets for antigen-specific immunotherapies, we performed a comprehensive analysis of the expression and immunogenicity of cancer-testis antigens in CML. METHODS: 10 CML cell lines and bone marrow samples from 10 healthy donors were screened by RT-PCR for the expression of 30 CT antigens. Cell lines were analyzed before and after stimulation with 5#8217;-Aza-2#8217;-Deoxcytidine and Trichostatine. Additionally, expression of PRAME was evaluated in 20 healthy tissues by quantitative RT-PCR. Expression of 15 selected CT antigens was then analyzed in BM and peripheral blood samples from 84 patients with CML by qualitative and quantitative RT-PCR. Protein expression was confirmed by Western Blot for 10 CT antigens. Finally, sera of 45 patients with CML were screened for antibodies against 15 CT antigens by ELISA. RESULTS: RT-PCR showed expression of CABYR, CT45, DKK1, HAGE, KM-HN-1, MPHOSPH1, PASD1, PBK and SP17 in BM samples from healthy donors, these genes were excluded from further analysis. 16 of the remaining 21 antigens were expressed in at least one untreated cell line, with PRAME showing the most frequent expression (N=8). Treatment with 5#8217;-Aza-2#8217;-Deoxycytidine led to a two-fold increase in the average number of CT antigens expressed per cell line while treatment with Trichostatine had a less pronounced effect (17% increase). Analyzing BM and blood samples from patients with CML, PRAME was found in 32.1% of the samples and expression correlated significantly with stage of disease (p=0.02) and blast cell count (r=0.38; p=0.01). Sporadic expression was only detected for BAGE2 (N=2) and SLLP1 (N=1). Importantly, in 20 healthy tissues, PRAME was indeed characteristically restricted to germ-line tissues. While none of the patients showed PRAME-specific serological immune responses, one patient who had not expressed NY-ESO-1 showed a significant antibody response against this antigen. CONCLUSIONS: CT antigens are frequently expressed in CML cell lines and expression can be increased by application of demethylating agents and histone deacetylase inhibitors. Most frequently detected in BM and peripheral blood samples from patients with CML was PRAME, whose expression correlated significantly with multiple clinicopathological parameters. While PRAME does not seem to spontaneously evoke frequent serological immune responses in CML patients, one patient who had not expressed NY-ESO-1 showed a significant antibody response against this antigen, possibly indicating spontaneous immunity leading to the eradication of CML clones expressing this antigen in vivo. Citation Information: In: Proc Am Assoc Cancer Res; 2009 Apr 18-22; Denver, CO. Philadelphia (PA): AACR; 2009. Abstract nr 4172.