Novel therapeutic targets in multiple myeloma

Harnessing Nanotechnology: Emerging Strategies for Multiple Myeloma Therapy

Advances in nanotechnology have provided novel avenues for the diagnosis and treatment of multiple myeloma (MM), a hematological malignancy characterized by the clonal proliferation of plasma cells in the bone marrow. This review elucidates the potential of nanotechnology to revolutionize myeloma therapy, focusing on nanoparticle-based drug delivery systems, nanoscale imaging techniques, and nano-immunotherapy. Nanoparticle-based drug delivery systems offer enhanced drug targeting, reduced systemic toxicity, and improved therapeutic efficacy. We discuss the latest developments in nanocarriers, such as liposomes, polymeric nanoparticles, and inorganic nanoparticles, used for the delivery of chemotherapeutic agents, siRNA, and miRNA in MM treatment. We delve into nanoscale imaging techniques which provide spatial multi-omic data, offering a holistic view of the tumor microenvironment. This spatial resolution can help decipher the complex interplay between cancer cells and their surrounding environment, facilitating the development of highly targeted therapies. Lastly, we explore the burgeoning field of nano-immunotherapy, which employs nanoparticles to modulate the immune system for myeloma treatment. Specifically, we consider how nanoparticles can be used to deliver tumor antigens to antigen-presenting cells, thus enhancing the body's immune response against myeloma cells. In conclusion, nanotechnology holds great promise for improving the prognosis and quality of life of MM patients. However, several challenges remain, including the need for further preclinical and clinical trials to assess the safety and efficacy of these emerging strategies. Future research should also focus on developing personalized nanomedicine approaches, which could tailor treatments to individual patients based on their genetic and molecular profiles.

Oncolytic measles virus targets high CD46 expression on multiple myeloma cells

OBJECTIVE

Multiple myeloma (MM) is an incurable B cell malignancy and novel therapeutics are urgently needed. Live attenuated measles virus (MV) has potent oncolytic activity against MM tumor xenografts. The virus is tumor selective and preferentially targets cells that express high levels of CD46 receptors. However, CD46 levels on MM have not previously been evaluated. In this study, we investigated the potential of CD46 as a target for MM therapy and correlated surface levels of CD46 on MM cells with their susceptibility to MV-induced cytopathic effects.

MATERIALS AND METHODS

CD46 expression on neoplastic plasma cells (PCs) and nonplasma cells (NPCs) from 38 MM patients was analyzed by flow cytometry and receptor numbers were quantitated using BD QuantiBRITE PE beads.

RESULTS

Results showed that malignant PCs expressed significantly higher levels of CD46 receptors compared to NPCs (p < 0.0001). The mean CD46 receptor numbers on PCs and NPCs were 49,130/cell and 7,340/cell, respectively. Potent cytopathic effects of extensive intercellular fusion were observed in measles-infected PCs but not in NPCs. The extent of MV-induced cytopathic effects of cell fusion correlated with CD46 expression levels on the MM cells. Normal plasma cells do not overexpress CD46 and colony-forming assays demonstrated that MV was not cytotoxic to normal bone marrow progenitor cells.

CONCLUSION

The present study establishes CD46 as a surface antigen that is expressed more abundantly on primary MM cells compared to normal hematopoietic cells of various lineages in the bone marrow, making CD46 a promising surface marker for targeted cytoreductive therapy of MM.

Evaluation of plasma cell propidium-iodide and annexin-V indices: their relation to prognosis in multiple myeloma

In a group of 117 patients with multiple myeloma (MM) examined at the time of diagnosis, i.e. excluding previous chemotherapy, we analysed the levels of propidium-iodide (proliferative) - PC-PI/CD(138) and annexin-V (apoptotic) - PC-AI/CD(138) indices of myeloma plasmocytes using the method of flow-cytometry to determine their relationship to prognosis. It was revealed that patients with high values of PC-PI/CD(138) had substantially worse overall survival than those with low values. Patients with a level of propidium-iodide index > or = 2,8 % exprimed a median survival of 13 months only in comparison with 42 months in patients with levels < 2,8 % (p = 0,0005). In the PC-AI/CD(138) index a reverse trend was registered. Patients with PC-AI/CD(138) > or = 4,0 % had long overall survival (median was not assessable at the time of evaluation), whereas patients with low apoptosis values < 4,0 % had median overall survival 16 months only (p = 0,01). Based on the sequentional graphic analysis of the curves of overall survival was found that the optimal discrimination level sequestering patients with good and poor prognosis was, in the case of PC-PI/CD(138) value 2,8 %, whereas in the case of PC-AI/CD(138) value 4,0 %. Among patients with good prognosis, there were no statistically significant differences in overall survival according to different levels of proliferative and apoptotic index. We conclude that evaluation of the propidium-iodide and annexin-V index using flow-cytometry is a quick, useful, and easily accessible method for the evaluation of plasma cell kinetics and thus prognosis of the disease, multiple myeloma.

Bone marrow angiogenesis and progression in multiple myeloma: clinical significance and therapeutic approach

It is now well established that solid tumors depend on angiogenesis. Promoters and inhibitors of angiogenesis are in balance and antiangiogenic strategies aim at repressing the angiogenic process, thus retarding solid tumor progression. Recent data suggest the importance of angiogenesis in hematologic malignancies and several studies reveal an increased angiogenesis in active multiple myeloma. Angiogenesis seems to be a prominent feature of MM progression, and seems to be correlated with the prognosis and the resistance of MM to chemotherapy. Numerous cell populations and cytokines are involved in angiogenesis in multiple myeloma and antiangiogenic therapy with thalidomide is effective in patients with refractory or relapsed disease. The combination of thalidomide and of other immunomodulatory agents with other therapeutic regimens could lead to more effective management of patients with multiple myeloma.

Upregulation of matrix metalloproteinase-9 in murine 5T33 multiple myeloma cells by interaction with bone marrow endothelial cells

MM is a B-cell malignancy mainly characterized by monoclonal expansion of plasma cells in the BM, presence of paraprotein in serum and occurrence of osteolytic bone lesions. MMPs are a family of proteolytic enzymes that can contribute to cancer growth, invasion, angiogenesis, bone degradation and other processes important in the pathogenesis of MM. We investigated MMP-9 production in the 5T33MM murine model. Expression of MMP-9 protein in supernatant and cell extracts was analyzed by gelatin zymography. The in vitro, stroma-independent variant 5T33MMvt showed no protein expression of MMP-9 in contrast to in vivo growing MM cells, 5T33MMvv. However, when 5T33MMvt cells were injected into naive mice and isolated after tumor take (5T33MMvt-vv), they secreted a significant amount of MMP-9. These results were confirmed by specific staining of cytospins with an anti-MMP-9 antibody. The MMP-9 production by 5T33MMvt-vv cells disappeared when the cells were recultured in vitro. These data demonstrated that upregulation of MMP-9 occurs in vivo and that this process is dependent on the microenvironment. Cocultures of 5T33MMvt cells with STR10 BMECs induced MMP-9 in MM cells, as determined by both gelatin zymography and flow-cytometric analysis. In conclusion, our results demonstrate that MMP-9 production by MM cells is upregulated in vivo by the interaction of MM cells with BMECs.

Molecular aspects of multiple myeloma

Multiple myeloma is a malignant tumour of plasma cells with a median survival of two to three years. Karyotypic instability is seen at the earliest stage of the disease and increases with disease progression, leading to extreme genetic abnormalities similar to solid tumours. Translocations involving the immunoglobulin heavy chain region on chromosome 14q32 are clearly important in the pathogenesis of most myelomas. This review focuses on the different genetic abnormalities found in myeloma and discusses possible pathogenetic mechanisms and the implications for biologically based treatments.

Novel therapies for multiple myeloma

Multiple myeloma (MM) continues to evade cure by conventional therapies, increasing the urgency for new, biologically based treatments. Reviewed in this discussion are novel chemotherapies under clinical trial that capitalize upon greater comprehension of tumor pathophysiology. In targeting tumor biology, these therapies serve as a model of treatment with great potential for improving outcomes in patients with MM.

Multiple myeloma

Multiple myeloma (MM) is a malignancy of the plasma cell characterized by migration and localization to the bone marrow where cells then disseminate and facilitate the formation of bone lesions. Unfortunately, while treatment of this disease is effective in palliating the disease, and even prolonging survival, this disease is generally regarded as incurable. Understanding the basic biology of myeloma cells will ultimately lead to more effective treatments by developing target based therapy. In Section I, Dr. Bergsagel discusses the molecular pathogenesis of MM and shares insights regarding specific chromosomal translocations and their role in the genesis and progression of MM. New information regarding FGFR3 as an oncogene as well as how activating mutations may contribute to disease evolution and may be an important target for novel therapeutics of MM is presented. In Section II, Dr. Anderson elaborates on novel therapeutic approaches to MM also targeting fundamental genetic abnormalities in MM cells. Both preclinical and clinical studies of novel agents including PS-341 and IMiDs are highlighted. In Section III, Dr. Harousseau discusses the role of autologous stem cell transplant in MM. He highlights clinical trials addressing the question of conditioning regimens and the impact of tandem transplants. He also addresses the role of allogeneic BMT and the use of attenuated dose conditioning regimens (so called mini-allogeneic transplants) in the treatment of MM. In Section IV, Dr. Dalton provides an overview of the current state of myeloma therapy and summarizes the different and exciting approaches being undertaken to cure this disease.

Manumycin inhibits farnesyltransferase and induces apoptosis of drug-resistant interleukin 6-producing myeloma cells

Interleukin 6 (IL-6) is an important survival and growth factor for myeloma cells and exerts its effects by activating several transduction pathways, including the Ras cascade. As farnesylation of the activated Ras oncogene product by protein farnesyltransferase (FTase) is a critical step for Ras functional activity, FTase has emerged as a potential target for the development of new anti-cancer agents. Based on our previous demonstration that IL-6-producing myeloma cells are refractory to drug-induced apoptosis, we have analysed the effect of manumycin, a natural FTase inhibitor, on IL-6-producing myeloma cells resistant to Fas-, dexamethasone- and doxorubicin-induced apoptosis. Treatment of myeloma cells with manumycin prevented cell proliferation and induced apoptosis. Western blotting experiments demonstrated that this effect was related to inhibition of the post-translational Ras processing.Further analysis showed that manumycin-induced apoptosis involved caspase-3. Activation of caspase-3, in fact, was observed in 6 h-treated myeloma cells expressing Apo 2.7 antigen, the marker of early apoptosis, whereas their treatment with cell-permeable DEVD-fmk, that irreversibly inhibits caspase-3 activity, prevented their apoptosis. Over-expression of caspase-3 was also demonstrated by reverse transcription-polymerase chain reaction. Finally, over-expression of Bcl-2 and its homologue Bcl-xL was observed in manumycin-treated cells as well as in control myeloma cells, implying that the Bcl-2 family is not involved. FTase inhibitors may thus be proposed as a potential pharmacological weapon, as they block the Ras pathway and induce the apoptosis of drug-resistant IL-6-producing myeloma cells.

Targeted therapy for multiple myeloma

Multiple myeloma (MM) remains incurable with conventional treatment approaches, and novel biologically based therapies are therefore urgently needed. Targeted therapies are either under development or already undergoing clinical evaluation predicated upon: identifying genetic abnormalities in myeloma cells to enhance chemoradiosensitivity; interrupting growth or triggering apoptotic signaling cascades in tumor cells; treating both the tumor cell and its microenvironment; enhancing allogeneic and autologous antimyeloma immunity; and characterizing new myeloma antigens for serotherapy. These therapies, alone or in combination with conventional treatments, offer great promise to improve the outcome for patients with MM.