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B022 The Effect of Bortezomib on Myeloma Cell Line
Section B Basic Biology and Preclinical Studies Clinical Lymphoma & Myeloma, Vol. 9, Suppl. 2, S96-S168, 2009; DOI: 10.3816/CLM.2009.s.010 1
Faculty Hospital Brno; 2Faculty of Science, Masaryk University;
B012
3
Efficacy and Safety of Anti-b2M mAbs to Treat MM J Yang, Y Cao, S Hong, HY Li, LW Kwak, Q Yi The University of Texas M. D. Anderson Cancer Center
We recently demonstrated that anti–b2-microglobulin monoclonal antibodies (anti-b2M mAbs) have remarkably strong apoptotic effects on myeloma in vitro and in SCID mice. However, whether the mAbs will be therapeutic and safe in treating myeloma patients, in whom every tissue expresses low densities of MHC class I molecules and elevated levels of soluble b2M are present, remains to be determined. In this study, we examined the antimyeloma activity and potential toxicity of the mAbs in a human-like situation. We developed and used a myeloma-HLA-A2-transgenic NOD/SCID mouse model. After myeloma establishment in NOD/SCID mice transgenic for HLA-A2 a-chain, we found that all tissues express human HLA-A2 and b2M and detected high levels of circulating human b2M. After 1 intraperitoneal injection of the mAbs (1 mg per mouse), the mAbs could be detected on the surface of tumors and murine organs. By using the model, we first examined the therapeutic efficacy of the mAbs on established myeloma. Myeloma-bearing mice were intraperitoneally injected with the mAbs (1 mg per mouse) twice a week for a total of 4 injections. The results showed that the mAbs effectively suppress myeloma growth, and activate caspases-9 and -3 and induce myeloma cell apoptosis in vivo. We also examined whether the mAbs damage human MHC class I–expressing normal cells and tissues. After treatment with the mAbs, murine organs were removed for histologic examination. We found that although the mAbs were detected on different organs, no tissue damage or cell apoptosis was observed in the mice. We further quantified the numbers of surface b2M and found that myeloma cells have approximately 265,918 surface b2M molecules, whereas normal blood lymphocytes have approximately 79,521, indicating that myeloma cells express 3-fold more surface b2M than lymphocytes. Myeloma cells treated with specific siRNAs for human b2M expressed a similarly low level of b2M (91,723) and became resistant to mAb-induced apoptosis. These findings indicate that the mAbs might be safe and that the tissue-expressed and soluble b2M might not compromise their therapeutic effects in myeloma patients. This study provides further support for the future application of the mAbs as therapeutic agents for myeloma.
B022 The Effect of Bortezomib on Myeloma Cell Line A Potacova,1 J Cumova,1 I Kasalova,2 O Sedo,2 Z Zdrahal,2 R Hajek3
Faculty Hospital Brno, Faculty of Medicine, Masaryk University,
Czech Republic
Introduction: Multiple myeloma (MM) is still an incurable disease characterized by the clonal expansion of malignant plasma cells. New anticancer drugs further improve prognosis of myeloma patients. The aim of this study was to evaluate changes in protein expression of myeloma cell line ARH 77 after bortezomib treatment. Materials and Methods: Myeloma cell line ARH 77 was treated with bortezomib (10-40 nM) for various periods of time (24 and 48 hours). The proteins contained in total myeloma cell lysate were separated by 2-dimensional polyacrylamide gel electrophoresis (2D-PAGE), and the differentially expressed proteins between the untreated and treated cell lines were excised and identified by mass spectrometry. Results: Analyzed were 94 proteins differentially expressed between treated and control cells; 34 protein spots were upregulated: proteins involved in regulation of apoptosis, chaperones/stress-related proteins, proteolysis of ubiquitin/protein degradation and cytoskeleton proteins. Sixty protein spots were downregulated: proteins involved in synthesis and regulation of apoptosis, chaperones/stress-related proteins, regulation of cellcycle proteins, proteins connected to glycolysis and proteolysis of ubiquitin/protein degradation, and antioxidant/redox proteins. Conclusion: We identified 94 proteins altered in myeloma cells after various exposure of to bortezomib. This proteomic approach can contribute to elucidation of mechanisms of new anticancer drugs action. This work is supported by grants of the Ministry of Education, Youth and Sports; Czech Republic: LC06027, MSM0021622434
B026 CS1 Promotes Multiple Myeloma Cell Adhesion, Clonogenic Growth, and Tumorigenicity via c-Maf Mediation YT Tai, E Soydan, M Fulciniti, W Song, K Kim, F Hong, X-F Li, P Burger, M Rumizen, S Nahar, K Podar, D Chauhan, T Hideshima, NC Munshi, G Tonon, R Carrasco, KC Anderson Dana-Farber Cancer Institute
Cell membrane protein CS1 is highly expressed by tumor cells from the majority of multiple myeloma (MM) patients (> 95%) regardless of cytogenetic abnormalities and response to current treatments. We here show that CS1 knockdown using lentiviral short interfering RNA decreased phosphorylation of ERK1/2, Akt, and
This article might include the discussion of investigational and/or unlabeled uses of drugs and/or devices that might not be approved by the FDA. Electronic forwarding or copying is a violation of US and international copyright laws. Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by CIG Media Group, LP, ISSN #1557-9190, provided the appropriate fee is paid directly to Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923 USA. www.copyright.com 978-750-8400.
S96
•
Clinical Lymphoma & Myeloma Supplement February 2009
Faculty Hospital Brno; 2Faculty of Science, Masaryk University;
B012
3
Efficacy and Safety of Anti-b2M mAbs to Treat MM J Yang, Y Cao, S Hong, HY Li, LW Kwak, Q Yi The University of Texas M. D. Anderson Cancer Center
We recently demonstrated that anti–b2-microglobulin monoclonal antibodies (anti-b2M mAbs) have remarkably strong apoptotic effects on myeloma in vitro and in SCID mice. However, whether the mAbs will be therapeutic and safe in treating myeloma patients, in whom every tissue expresses low densities of MHC class I molecules and elevated levels of soluble b2M are present, remains to be determined. In this study, we examined the antimyeloma activity and potential toxicity of the mAbs in a human-like situation. We developed and used a myeloma-HLA-A2-transgenic NOD/SCID mouse model. After myeloma establishment in NOD/SCID mice transgenic for HLA-A2 a-chain, we found that all tissues express human HLA-A2 and b2M and detected high levels of circulating human b2M. After 1 intraperitoneal injection of the mAbs (1 mg per mouse), the mAbs could be detected on the surface of tumors and murine organs. By using the model, we first examined the therapeutic efficacy of the mAbs on established myeloma. Myeloma-bearing mice were intraperitoneally injected with the mAbs (1 mg per mouse) twice a week for a total of 4 injections. The results showed that the mAbs effectively suppress myeloma growth, and activate caspases-9 and -3 and induce myeloma cell apoptosis in vivo. We also examined whether the mAbs damage human MHC class I–expressing normal cells and tissues. After treatment with the mAbs, murine organs were removed for histologic examination. We found that although the mAbs were detected on different organs, no tissue damage or cell apoptosis was observed in the mice. We further quantified the numbers of surface b2M and found that myeloma cells have approximately 265,918 surface b2M molecules, whereas normal blood lymphocytes have approximately 79,521, indicating that myeloma cells express 3-fold more surface b2M than lymphocytes. Myeloma cells treated with specific siRNAs for human b2M expressed a similarly low level of b2M (91,723) and became resistant to mAb-induced apoptosis. These findings indicate that the mAbs might be safe and that the tissue-expressed and soluble b2M might not compromise their therapeutic effects in myeloma patients. This study provides further support for the future application of the mAbs as therapeutic agents for myeloma.
B022 The Effect of Bortezomib on Myeloma Cell Line A Potacova,1 J Cumova,1 I Kasalova,2 O Sedo,2 Z Zdrahal,2 R Hajek3
Faculty Hospital Brno, Faculty of Medicine, Masaryk University,
Czech Republic
Introduction: Multiple myeloma (MM) is still an incurable disease characterized by the clonal expansion of malignant plasma cells. New anticancer drugs further improve prognosis of myeloma patients. The aim of this study was to evaluate changes in protein expression of myeloma cell line ARH 77 after bortezomib treatment. Materials and Methods: Myeloma cell line ARH 77 was treated with bortezomib (10-40 nM) for various periods of time (24 and 48 hours). The proteins contained in total myeloma cell lysate were separated by 2-dimensional polyacrylamide gel electrophoresis (2D-PAGE), and the differentially expressed proteins between the untreated and treated cell lines were excised and identified by mass spectrometry. Results: Analyzed were 94 proteins differentially expressed between treated and control cells; 34 protein spots were upregulated: proteins involved in regulation of apoptosis, chaperones/stress-related proteins, proteolysis of ubiquitin/protein degradation and cytoskeleton proteins. Sixty protein spots were downregulated: proteins involved in synthesis and regulation of apoptosis, chaperones/stress-related proteins, regulation of cellcycle proteins, proteins connected to glycolysis and proteolysis of ubiquitin/protein degradation, and antioxidant/redox proteins. Conclusion: We identified 94 proteins altered in myeloma cells after various exposure of to bortezomib. This proteomic approach can contribute to elucidation of mechanisms of new anticancer drugs action. This work is supported by grants of the Ministry of Education, Youth and Sports; Czech Republic: LC06027, MSM0021622434
B026 CS1 Promotes Multiple Myeloma Cell Adhesion, Clonogenic Growth, and Tumorigenicity via c-Maf Mediation YT Tai, E Soydan, M Fulciniti, W Song, K Kim, F Hong, X-F Li, P Burger, M Rumizen, S Nahar, K Podar, D Chauhan, T Hideshima, NC Munshi, G Tonon, R Carrasco, KC Anderson Dana-Farber Cancer Institute
Cell membrane protein CS1 is highly expressed by tumor cells from the majority of multiple myeloma (MM) patients (> 95%) regardless of cytogenetic abnormalities and response to current treatments. We here show that CS1 knockdown using lentiviral short interfering RNA decreased phosphorylation of ERK1/2, Akt, and
This article might include the discussion of investigational and/or unlabeled uses of drugs and/or devices that might not be approved by the FDA. Electronic forwarding or copying is a violation of US and international copyright laws. Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by CIG Media Group, LP, ISSN #1557-9190, provided the appropriate fee is paid directly to Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923 USA. www.copyright.com 978-750-8400.
S96
•
Clinical Lymphoma & Myeloma Supplement February 2009