Biology and treatment of multiple myeloma

Proliferation and Angiogenesis Using Immunohistochemistry in Prognosticating Multiple Myeloma

Multiple myeloma is a neoplasm of plasma cells characterised by the presence of M protein in serum and urine. Angiogenesis and proliferation play a major role in the pathogenesis of various neoplasms. The study evaluated proliferation and angiogenesis in 48 cases of myeloma, and correlated it with morphological and clinical parameters. The histomorphological features like plasma cell morphology, percentage of plasma cells and pattern of infiltration were studied in the bone marrow aspirate and trephine biopsy. Angiogenesis was assessed by calculating the microvessel density (MVD) using immunohistochemistry for CD34. Proliferation was assessed using Ki67 and CD38 highlighted the plasma cells. The mean Ki67 % was found to be significantly higher (19.6 % range 2-40 %) in poorly differentiated morphology compared to well differentiated morphology (4.06 % range 0.2-20 %) (p = 0.003). The mean MVD in the well differentiated morphology was 10.6 (range 1.2-47.4) compared to 20.3 (range 6.9-39.6) in the poorly differentiated morphology (p = 0.04). The mean MVD was 5.7 (range 1.2-12.8) in the interstitial pattern of infiltration compared to 20.04 (2.9-47.4) in the diffuse pattern (p < 0.0001). The mean MVD was 6.4 in cases with serum albumin >3.5 gm/dl compared to 13.3 in cases with serum albumin <3.5 gm/dl (p = 0.009). Both the Ki67 and MVD showed an increasing trend with the clinical staging. Thus the study of proliferation and angiogenesis in bone marrow biopsy is useful for prognosticating patients with multiple myeloma.

Non-Secretory Myeloma, Diagnosed on Renal Biopsy as Cast Nephropathy

Multiple myeloma is a disorder of plasma cells which can involve kidneys in the form of cast nephropathy. Neoplastic plasma cells produce either complete immunoglobulins or fragments of immunoglobulins leading to a monoclonal spike in the serum and/or Bence Jones proteinuria. Very few patients present as non-secretory myeloma when no immunoglobulins (M spike) are produced or only light chains are secreted which can only be detected in urine. Acute renal failure due to cast nephropathy can rarely be the first presentation of multiple myeloma. We here in report a case in which primary diagnosis of multiple myeloma was made on renal biopsy due to its characteristic histomorphology. The diagnosis was later on supported by presence of neoplastic plasma cells in the aspirate and biopsy of bone marrow.

Therapeutic potential of cladribine in combination with STAT3 inhibitor against multiple myeloma

Background

Cladribine or 2-chlorodeoxyadenosine (2-CDA) is a well-known purine nucleoside analog with particular activity against lymphoproliferative disorders, such as hairy cell leukemia (HCL). Its benefits in multiple myeloma (MM) remain unclear. Here we report the inhibitory effects of cladribine on MM cell lines (U266, RPMI8226, MM1.S), and its therapeutic potential in combination with a specific inhibitor of the signal transducer and activator of transcription 3 (STAT3).

Methods

MTS-based proliferation assays were used to determine cell viability in response to cladribine. Cell cycle progression was examined by flow cytometry analysis. Cells undergoing apoptosis were evaluated with Annexin V staining and a specific ELISA to quantitatively measure cytoplasmic histone-associated DNA fragments. Western blot analyses were performed to determine the protein expression levels and activation.

Results

Cladribine inhibited cell proliferation of MM cells in a dose-dependent manner, although the three MM cell lines exhibited a remarkably different responsiveness to cladribine. The IC50 of cladribine for U266, RPMI8226, or MM1.S cells was approximately 2.43, 0.75, or 0.18 μmol/L, respectively. Treatment with cladribine resulted in a significant G1 arrest in U266 and RPMI8226 cells, but only a minor increase in the G1 phase for MM1.S cells. Apoptosis assays with Annexin V-FITC/PI double staining indicated that cladribine induced apoptosis of U266 cells in a dose-dependent manner. Similar results were obtained with an apoptotic-ELISA showing that cladribine dramatically promoted MM1.S and RPMA8226 cells undergoing apoptosis. On the molecular level, cladribine induced PARP cleavage and activation of caspase-8 and caspase-3. Meanwhile, treatment with cladribine led to a remarkable reduction of the phosphorylated STAT3 (P-STAT3), but had little effect on STAT3 protein levels. The combinations of cladribine and a specific STAT3 inhibitor as compared to either agent alone significantly induced apoptosis in all three MM cell lines.

Conclusions

Cladribine exhibited inhibitory effects on MM cells in vitro. MM1.S is the only cell line showing significant response to the clinically achievable concentrations of cladribine-induced apoptosis and inactivation of STAT3. Our data suggest that MM patients with the features of MM1.S cells may particularly benefit from cladribine monotherapy, whereas cladribine in combination with STAT3 inhibitor exerts a broader therapeutic potential against MM.

Preferential killing of PTEN-null myelomas by PI3K inhibitors through Akt pathway

We recently reported that internal deletion of PTEN tumor suppressor gene in OPM2 and Delta47 myeloma lines led to high Akt activation. Re-expression of PTEN induced strong apoptosis and growth inhibition. To understand the biologic importance of the phosphatidylinositol 3 kinase (PI3K)/Akt activation affected by PTEN deletion, we analysed apoptosis and growth inhibition by applying PI3K inhibitors to myeloma lines and by expressing Akt constructs. The PI3K inhibitors preferentially suppressed PTEN-null myeloma growth to those expressing PTEN, indicating that PI3K activation is more critical for growth and survival of those lines with PTEN mutations than others expressing a functional PTEN gene. Since PTEN-null myeloma lines exhibited much stronger Akt activation than PTEN-expressing cells in response to insulin-like growth factor I stimulation, we determined whether Akt could be responsible for PI3K-mediated cell survival and growth of PTEN-null myeloma lines. Expression of an active Akt, but not its kinase dead mutant, reversed wortmannin- and dexamethasone-induced apoptosis and growth inhibition in PTEN-null myeloma lines, suggesting that Akt lies downstream of PI3K for PTEN-null myeloma survival and dexamethasone resistance. In summary, we have provided evidence that PTEN-null myeloma cells are stringently dependent on the PI3K/Akt activation for cell survival. These results may provide a basis to treat myeloma patients with PI3K and Akt inhibitors.

Members of the poly (rC) binding protein family stimulate the activity of the c-myc internal ribosome entry segment in vitro and in vivo

The 5' untranslated region of the proto-oncogene c-myc contains an internal ribosome entry segment and c-Myc translation can be initiated by cap-independent as well as cap-dependent mechanisms. In contrast to the process of cap-dependent initiation, the trans-acting factor requirements for cellular internal ribosome entry are poorly understood. Here, we show that members of the poly (rC) binding protein family, poly (rC) binding protein 1 (PCBP1), poly (rC) binding protein 2 (PCBP2) and hnRNPK were able to activate the IRES in vitro up to threefold when added in combination with upstream of N-ras and unr-interacting protein. The interactions of PCBP1, PCBP2 and hnRNPK with c-myc-IRES-RNA were shown to be specific by ultraviolet crosslinking analysis and electrophoretic mobility shift assays, while immunoprecipitation of the three proteins using specific antibodies followed by reverse transcriptase-polymerase chain reaction showed that they were able to bind c-myc mRNA. c-myc-IRES-mediated translation from the reporter vector was stimulated by cotransfection of plasmids encoding PCBP1, PCBP2 and hnRNPK. Interestingly, the mutated version of the c-myc IRES that is prevalent in patients with multiple myeloma bound hnRNPK more efficiently in vitro and was stimulated by hnRNPK to a greater extent in vivo.

Nuclear factor kappaB-dependent gene expression profiling of Hodgkin's disease tumor cells, pathogenetic significance, and link to constitutive signal transducer and activator of transcription 5a activity

Constitutive nuclear nuclear factor (NF)-kappaB activity is observed in a variety of hematopoietic and solid tumors. Given the distinctive role of constitutive NF-kappaB for Hodgkin and Reed-Sternberg (HRS) cell viability, we performed molecular profiling in two Hodgkin's disease (HD) cell lines to identify NF-kappaB target genes. We recognized 45 genes whose expression in both cell lines was regulated by NF-kappaB. The NF-kappaB-dependent gene profile comprises chemokines, cytokines, receptors, apoptotic regulators, intracellular signaling molecules, and transcription factors, the majority of which maintain a marker-like expression in HRS cells. Remarkably, we found 17 novel NF-kappaB target genes. Using chromatin immunoprecipitation we demonstrate that NF-kappaB is recruited directly to the promoters of several target genes, including signal transducer and activator of transcription (STAT)5a, interleukin-13, and CC chemokine receptor 7. Intriguingly, NF-kappaB positively regulates STAT5a expression and signaling pathways in HRS cells, and promotes its persistent activation. In fact, STAT5a overexpression was found in most tumor cells of tested patients with classical HD, indicating a critical role for HD. The gene profile underscores a central role of NF-kappaB in the pathogenesis of HD and potentially of other tumors with constitutive NF-kappaB activation.

Extended survival in advanced-stage multiple myeloma patients treated with gallium nitrate

Adjunctive anti-bone resorption therapy has become an important part of multiple myeloma (MM) treatment. Currently, no definite evidence exists that this therapy increases survival. We examined a cohort of 13 of 167 patients (8%) treated with the M-2 protocol who received adjuvant gallium nitrate (GN) treatment for osteolysis, and then compared the outcome of these patients to all individuals treated with the M-2 regimen. The stage at diagnosis was IA in two patients, IIIA in 10 patients and IIIB in one. Median age at diagnosis was 51 years (range 35-73). Median (range) of entry data were: paraprotein level: 6000mg/dl (3058-8675); beta2M: 2.7mg/l, (1.2-9.6); LDH: 166U/l (142-237); hemoglobin: 10.2 g/dl (8.3-12.6); albumin: 3.7 g/dl (2.5-5.0); calcium: 10.0 mg/dl (8.3-14.5); creatinine: 1.2 mg/dl (0.7-2.7). Median survival in these patients was 87+ months from time of diagnosis compared with 48 months for all other patients treated on the M-2 protocol. We identified a subgroup of patients with remarkably prolonged survival who had received M-2 chemotherapy and GN. Survival in this group markedly exceeds expectations for patients with advanced stage disease and poor prognostic features. The administration of GN may have a positive impact on survival either by decreasing skeletal complications or through a direct action of GN on the complex cytokine network involved in the proliferation of the malignant myeloma cell.

Mechanisms of Interferon-alpha induced apoptosis in malignant cells

Interferon alpha (IFNalpha) has been used in the treatment of several types of cancer for almost 30 years, yet the mechanism(s) responsible for its anti-tumoral action remains unknown. A variety of cellular responses, including inhibition of cell growth and induction of apoptosis are induced by IFNs, and apoptotic induction by this cytokine has been proposed to be of importance for both its anti-tumoral in addition to its anti-viral responses. The aim of the present study was to delineate the pathways activated during IFNalpha-induced apoptosis in malignant cell lines. We found that apoptosis induced by IFNalpha was associated with activation of caspases-1, -2, -3, -8 and -9 and that this activation was a critical event. Caspase-3 activation was dependent on activity of caspases-8 and -9, moreover, activation of caspase-8 seems to be the upstream event in IFNalpha-induced caspase cascade. We also found loss of mitochondrial membrane potential as well as release of cytochrome c post IFN-treatment, clearly implicating the involvement of mitochondria in IFN-mediated apoptosis. Furthermore, IFNalpha-induced apoptosis was found to be independent on interactions between the Fas-receptor and its ligand. These studies form the basis for further investigations aiming to improve IFN therapy and the development of future strategies to overcome the IFN resistance observed in some malignancies.

Monoclonal antibody identifies a distinctive epitope expressed by human multiple myeloma cells

Employing a technology called differential immunization for antigen and antibody discovery (DIAAD), we aimed to generate monoclonal antibodies (mAbs) specific to human multiple myeloma (MM) cells. The fundamental principles of DIAAD rely on the induction of high zone tolerance to the "wild type" (normal) antigen. followed by immunization with the modified (diseased) antigen. Because chronic myelogenic leukemia (CML) cells are derived from a lineage closely related to MM, we immunized mice by contrasting a pool of MM cells with CML cells. Monoclonal antibody VAC69 reacted exclusively with MM cells, identifying a membrane molecule composed of a single-chain glycoprotein with a molecular weight of 78-120 kd. This antigen exhibited narrow tissue specificity and was not found on human cancers such as prostate, breast, or cervical carcinoma; leukemia; or lymphoma, nor was it seen on normal human peripheral lymphocytes or on Epstein-Barr virus-transformed B-cell lines. By immunohistochemistry, mAb VAC69 showed no binding to antigens expressed on normal human ovary, breast, prostate, lung or colon tissue, nor did it bind to human breast or prostate cancer. Conversely, mAb VAC69 bound strongly to human MM, although showing only slight binding to histiocytes or inflamed cells in human lymph nodes and human tumors of the colon, lung, and ovary. Monoclonal antibody VAC69 also triggered cancer-specific cytotoxicity in vitro (in the presence of complement) as well as in vivo using a sever combined immunodeficiency model transplanted with human MM. Further studies showed the ability of mAb VAC69 to be specifically internalized by human MM cells, indicating its potential use for therapeutic intervention in MM by delivering drugs into cancer cells.

Malignancy: Myeloma - the Elusive Cure

Myeloma accounts for 1% of all malignancies and is characterised by the malignant expansion of plasma cells. It is essentially incurable with a median survival of 6 months untreated. Typically disseminated at presentation, myeloma requires systemic therapy, in those patients with advanced or progressive disease. Of single agent therapies, oral mephalan remains the gold standard, either alone or in combination with steroids. 40% will respond with an increase in median survival from under 1 year to around 36 months. Combination chemotherapy produces an advantage in remission induction but no clear benefit for either survival or remission duration has been shown over standard melphalan and prednisolone. Significant melphalan dose escalation produces increased response rates and increased complete remission rates, however at the expense of increased toxicity. This has been ameliorated to an extent using stem cell support, however, although autografting may be superior to conventional chemotherapy it is not a curative treatment and modifications such as purging or tandem procedures remain to be fully evaluated. Allogeneic transplantation is only an option in a tiny minority of patients and has a high treatment-related mortality. Interferon alpha may improve the relapse free survival but has little effect on overall survival as the majority of patients will relapse. Experimental approaches, such as P-gp inhibition or thalidomide, are appropriate in this poor prognosis group. In many patients palliative care remains the only therapeutic option and close attention should be therefore paid to the prevention and treatment of renal failure, anaemia, infection, hypercalcaemia and bone disease.

Loss of PTEN expression leading to high Akt activation in human multiple myelomas

Mouse plasma cell tumor (PCT) and human multiple myeloma (MM) are terminal B-cell malignancies sharing many similarities. Our recent work demonstrated that activation of the insulin-like growth factor receptor (IGF-IR)/insulin receptor substrate (IRS)/phosphatidylinositol 3′ kinase (PI 3′K) pathway was evident in the tumor lines derived from both species. Although PI 3′K activity was higher in mouse tumor lines than that in human tumors, activation of Akt serine/threonine kinase was markedly lower in mouse lines. This discrepancy prompted us to test the status of PTEN tumor suppressor gene, as it has been shown to be a negative regulator of PI 3′K activity. Although all the mouse lines expressed intact PTEN, 2 of the 4 human lines (Δ47 and OPM2) possessing the highest Akt activity lost PTEN expression. Sequencing analysis demonstrated that the PTEN gene contains a deletion spacing from exon 3 to exon 5 or 6 in the Δ47 line and from exon 3 to 7 in the OPM2 line. Restoration of PTEN expression suppressed IGF-I–induced Akt activity, suggesting that loss of PTEN is responsible for uncontrolled Akt activity in these 2 lines. Despite the expression of PTEN with the concomitant low Akt activity in all mouse PCT lines, their p70S6K activities were generally higher than those in 3 human MM lines, arguing for specific negative regulation of Akt, but not p70S6K by PTEN. These results suggest that p70S6K and Akt may be differentially used by the plasma cell tumors derived from mice and humans, respectively.

Loss of PTEN expression leading to high Akt activation in human multiple myelomas

Mouse plasma cell tumor (PCT) and human multiple myeloma (MM) are terminal B-cell malignancies sharing many similarities. Our recent work demonstrated that activation of the insulin-like growth factor receptor (IGF-IR)/insulin receptor substrate (IRS)/phosphatidylinositol 3′ kinase (PI 3′K) pathway was evident in the tumor lines derived from both species. Although PI 3′K activity was higher in mouse tumor lines than that in human tumors, activation of Akt serine/threonine kinase was markedly lower in mouse lines. This discrepancy prompted us to test the status of PTEN tumor suppressor gene, as it has been shown to be a negative regulator of PI 3′K activity. Although all the mouse lines expressed intact PTEN, 2 of the 4 human lines (Δ47 and OPM2) possessing the highest Akt activity lost PTEN expression. Sequencing analysis demonstrated that the PTEN gene contains a deletion spacing from exon 3 to exon 5 or 6 in the Δ47 line and from exon 3 to 7 in the OPM2 line. Restoration of PTEN expression suppressed IGF-I–induced Akt activity, suggesting that loss of PTEN is responsible for uncontrolled Akt activity in these 2 lines. Despite the expression of PTEN with the concomitant low Akt activity in all mouse PCT lines, their p70S6K activities were generally higher than those in 3 human MM lines, arguing for specific negative regulation of Akt, but not p70S6K by PTEN. These results suggest that p70S6K and Akt may be differentially used by the plasma cell tumors derived from mice and humans, respectively.

Constitutive expression of IL-6-LIKE cytokines in normal bone marrow: implications for pathophysiology of myeloma

Myeloma is a neoplasm thought to "home" to bone marrow. However, evidence for bone-marrow-specific receptors or adhesion molecules expressed on myeloma cells is scanty. Initial myeloma expansion is thought to be due to IL-6 and/or related cytokines. Previous determinations of cytokine expression in bone marrow were performed on bone marrow stromal lines; these findings may not reflect the constitutive pattern of expression in situ. Intracytoplasmic staining for IL-6-like cytokines revealed constitutive expression of some factors in the bone marrow of normal mice, but not spleens. Spleens of myeloma-transplanted SCID mice expressed IL-6-like cytokines, indicative of induction of expression by myeloma. Some cytokines expressed in bone marrow induced myeloma proliferation in the presence of dexamethasone, demonstrating dependence of the myeloma on these cytokines. Our data imply that, rather than "homing" to bone marrow, myeloma cells proliferated within marrow cavities more than in other organs because of growth factors constitutively expressed by bone marrow cells. As myeloma progressed, we observed the induction of growth factor expression in spleen cells. Furthermore, because cytokines other than IL-6 may induce myeloma cell proliferation, therapy aimed at neutralizing IL-6 may not be the most effective method to treat this disease. These findings have implications for both the pathophysiology and therapy of multiple myeloma.

A mutation in the c-myc-IRES leads to enhanced internal ribosome entry in multiple myeloma: a novel mechanism of oncogene de-regulation

The 5' untranslated region of the proto-oncogene c-myc contains an internal ribosome entry segment (IRES) (Nanbru et al., 1997; Stoneley et al., 1998) and thus c-myc protein synthesis can be initiated by a cap-independent as well as a cap-dependent mechanism (Stoneley et al., 2000). In cell lines derived from patients with multiple myeloma (MM) there is aberrant translational regulation of c-myc and this correlates with a C-T mutation in the c-myc-IRES (Paulin et al., 1996). RNA derived from the mutant IRES displays enhanced binding of protein factors (Paulin et al., 1998). Here we show that the same mutation is present in 42% of bone marrow samples obtained from patients with MM, but was not present in any of 21 controls demonstrating a strong correlation between this mutation and the disease. In a tissue culture based assay, the mutant version of the c-myc-IRES was more active in all cell types tested, but showed the greatest activity in a cell line derived from a patient with MM. Our data demonstrate that a single mutation in the c-myc-IRES is sufficient to cause enhanced initiation of translation via internal ribosome entry and represents a novel mechanism of oncogenesis.

Translational control of growth factor and proto-oncogene expression

Control of translation is now understood to be one of the major regulatory events in eukaryotic gene expression. Moreover there is evidence which suggests that aberrant expression of growth-related genes by translational mechanisms makes a significant contribution to cell transformation. However, the mechanisms which regulate translation of specific growth-related mRNAs have yet to be fully elucidated. The majority of these mRNAs have long 5' untranslated regions (UTRs) and three features which are important in translational control have been identified, namely (i) structured regions which inhibit the scanning mechanisms of translation, (ii) regulatory upstream open reading frames and (iii) internal ribosome entry segments which are capable of initiating cap-independent translation. In this review the translational regulation of specific mRNAs encoding growth factors and proto-oncogenes by these three mechanisms will be discussed, together with examples of altered translational regulation in neoplasia.

Human myeloma cell apoptosis induced by interferon-alpha

Although there have been reports regarding the clinical effectiveness of IFN alpha in the treatment of myeloma patients during this decade, its biological effects on human myeloma cells have still not been clarified. Recently, apoptosis has been considered as one of the most important mechanisms in the programmed cell death of malignant tumour cells induced by chemotherapeutic agents or cytotoxic immunological defence in malignancy-carrying hosts. Among the several pathways which function to induce apoptosis, Fas and the Fas ligand system have been thought to play an important role in inducing tumour-cell apoptosis, particularly in immunological prevention. In this study we investigated myeloma cell apoptosis induced by IFN alpha using five human myeloma cell lines which were established without any additional supplementation of IL-6. In addition, the mRNA expression levels of apoptosis-related genes employing the reverse transcriptase-polymerase chain reaction (RT-PCR) were also analysed with the KMS-12-PE cell line, which was the most sensitive of the five cell lines in terms of apoptosis induced by IFN alpha. Based on the results, it was determined that IFN alpha induced myeloma cell apoptosis in a dose-dependent manner, but the sensitivity to IFN alpha in the cell lines examined varied and one cell line revealed growth stimulation by IFN alpha. In addition, the apoptosis induced by IFN alpha did not seem to be mediated by the Fas/Fas ligand pathway. Finally, the IL-6, IL-6R, IRF1 and IRF2 genes were up-regulated in KMS-12-PE cells cultured with IFN alpha. Therefore these genes may play an important role during apoptosis induced by IFN alpha.

Increased sialylation of oligosaccharides on IgG paraproteins--a potential new tumour marker in multiple myeloma

AIMS

To investigate whether changes in carbohydrate structure of IgG are related to malignancy and stage of disease in myeloma and monoclonal gammopathy of uncertain significance (MGUS).

METHODS

61 patients were studied at diagnosis: 14 with MGUS, nine with stage I multiple myeloma, 11 with stage II, 21 with stage III, and five with solitary plasmacytoma. IgG was extracted from serum by protein G affinity chromatography. Oligosaccharides were cleaved from the protein backbone enzymatically by N-glycosidase F. Oligosaccharide analysis was performed by high pressure anion exchange chromatography with pulsed electrochemical detection (HPAE-PED).

RESULTS

Up to 15 oligosaccharide peaks were identified in three major fractions: neutral, monosialylated, and disialylated. Patients with myeloma showed an increase in the proportion of sialylated oligosaccharides in comparison with patients with MGUS. The ratio of neutral to sialylated oligosaccharides (N:S) was reduced at all stages of myeloma compared with MGUS: MGUS, 11.35; myeloma stage I, 7.6 (p = 0.047); stage II, 5.20 (p = 0.035); stage III, 3.60 (p = 0.0002); plasmacytoma, 7.5 (p = 0.046). The N:S ratio was independent of paraprotein concentration (r = 0.05).

CONCLUSIONS

The ratio of neutral to sialylated oligosaccharides may act as a new marker of malignancy in IgG paraproteinaemia and warrants further investigation.

VAD or VMBCP in multiple myeloma refractory to or relapsing after cyclophosphamide-prednisone therapy (protocol MY 85)

263 patients (median age 65+/-10 years) with multiple myeloma were treated with cyclophosphamide-prednisone. Out of this cohort, 103 patients had progressive disease and were randomly assigned to either VAD (vincristine, doxorubicin, dexamethasone; 50 cases) or VMBCP (vincristine, BCNU, cyclophosphamide, melphalan and prednisone; 53 cases). There were no statistical differences between the two groups with the respect to clinical, biological and radiological parameters. There was no difference in survival between the VAD and VMBCP groups. The 4 months response rate was similar in the two groups (50% VAD, 56% VMBCP). With multivariate analysis for survival (Cox model), two factors had a statistically significant impact: Karnofsky index (> 60) and albuminaemia (< 34 g/l). With both Karnofsky index > 60 and albuminaemia > or = 34 g/l, the median survival was 29 months v 2 months with a Karnofsky index < or = 60 and albuminaemia < 34 g/l (P<0.05). In conclusion, VAD or VMBCP had similar activity for salvage treatment in MM refractory or relapsing to first-line treatment with cyclophosphamide-prednisone.

A single nucleotide change in the c-myc internal ribosome entry segment leads to enhanced binding of a group of protein factors

A 340 nucleotide section of the c- myc 5' untranslated region (UTR) contains an internal ribosome entry segment. We have described previously a mutation in this region of RNA in cell lines derived from patients with multiple myeloma (MM) which exhibit increased expression of c- myc protein by an aberrant translational mechanism. In this study we show by electrophoretic mobility shift assays (EMSA), north-western blotting and UV cross-linking that radiolabelled c- myc 5' UTR RNA transcripts which harbour the mutation cause enhanced binding of cellular proteins. In addition, we also demonstrate that an MM derived cell line possesses an altered repertoire of RNA binding proteins. Our data suggest that the deregulated expression of c -myc in MM could result both from the effect of the mutation and the additional proteins which are present in these cell types.

Hexamethylene bisacetamide induces programmed cell death (apoptosis) and down-regulates BCL-2 expression in human myeloma cells

Multiple myeloma (MM) is a B cell malignancy characterized by the expansion of monoclonal Ig-secreting plasma cells with low proliferative activity. It is postulated that inhibition of physiologic cell death is an underlying factor in the pathophysiology of MM. The development of chemoresistance is a common feature in patients with MM. In the present studies, hexamethylene bisacetamide (HMBA), a hybrid polar compound that is a potent inducer of terminal differentiation of various transformed cells, is shown to inhibit the growth of several human myeloma cell lines (ARP-1, U266, and RPMI 8226), including doxorubicin-resistant RPMI 8226 variants that overexpress the multidrug-resistance gene, MDR-1, and its product, p-glycoprotein. In addition to growth arrest and suppression of clonogenicity, HMBA induces apoptosis both in freshly isolated human myeloma cells and in cell lines, as determined by morphologic alterations, cell cycle distribution and endonucleosomal DNA fragmentation. Further, HMBA decreases BCL-2 protein expression in myeloma cells within 12-48 hr. Overexpression of BCL-2 protein in ARP-1 cells confers resistance to HMBA-induced apoptosis. Taken together, these data suggest that HMBA is a potent inducer of apoptosis in human myeloma cells, which may act through suppressing the anti-apoptotic function of the bcl-2 gene. HMBA, and related hybrid polar compounds, may prove useful in the management of this presently incurable disease.

Mutations in the Fas Antigen in Patients With Multiple Myeloma

Programmed cell death, or apoptosis, is well documented as a physiological means of eliminating activated lymphocytes and maintaining immune homeostasis. Apoptosis has also been implicated in the targeting of tumor cells by cytotoxic T lymphocytes and natural killer cells. One of the two primary mechanisms used in cell-mediated cytotoxicity is the Fas/FasLigand system. Activated or transformed cells expressing the Fas antigen on their surface are susceptible to killing by immune effector cells that express the Fas ligand. Many neoplastic cells, including those derived from patients with multiple myeloma, express Fas antigen on their surface, but do not undergo apoptosis in response to antigen crosslinking. One possibility for the lack of Fas-mediated apoptosis includes mutations in the Fas antigen. Loss of function mutations in the Fas antigen have been associated with congenital autoimmune disease in humans, and have been defined as the genetic defect the in lpr mice. Mutations in the Fas antigen have not been previously described in cancer patients. In this study, we show that mutations occur in the Fas antigen which may cause loss of function and contribute to the pathogenesis of the neoplastic disease, multiple myeloma. Using reverse transcriptase-polymerase chain reaction (RT-PCR), single-stranded conformation polymorphism (SSCP) analysis, and DNA sequencing, we examined the cDNA structure of the Fas antigen in 54 bone marrow (BM) specimens obtained from myeloma patients. Six patient specimens (11%) did not express detectable levels of Fas antigen mRNA. Of the 48 BM specimens which did express Fas antigen, 5 (10%) displayed point mutations. All of the mutations identified were located in the cytoplasmic region of the Fas antigen known to be involved in transduction of an apoptotic signal. Two separate individuals demonstrated an identical mutation at a site previously shown to be mutated in the congenital autoimmune syndrome, ALPS. One patient exhibited a point mutation at a site only two amino acids removed from the documented lesion of the lprcg mouse. Although the functional status of these point mutations remains to be determined, we propose that Fas antigen mutations may contribute to the pathogenesis and progression of myeloma in some patients.

Mutations in the Fas Antigen in Patients With Multiple Myeloma

Programmed cell death, or apoptosis, is well documented as a physiological means of eliminating activated lymphocytes and maintaining immune homeostasis. Apoptosis has also been implicated in the targeting of tumor cells by cytotoxic T lymphocytes and natural killer cells. One of the two primary mechanisms used in cell-mediated cytotoxicity is the Fas/FasLigand system. Activated or transformed cells expressing the Fas antigen on their surface are susceptible to killing by immune effector cells that express the Fas ligand. Many neoplastic cells, including those derived from patients with multiple myeloma, express Fas antigen on their surface, but do not undergo apoptosis in response to antigen crosslinking. One possibility for the lack of Fas-mediated apoptosis includes mutations in the Fas antigen. Loss of function mutations in the Fas antigen have been associated with congenital autoimmune disease in humans, and have been defined as the genetic defect the in lpr mice. Mutations in the Fas antigen have not been previously described in cancer patients. In this study, we show that mutations occur in the Fas antigen which may cause loss of function and contribute to the pathogenesis of the neoplastic disease, multiple myeloma. Using reverse transcriptase-polymerase chain reaction (RT-PCR), single-stranded conformation polymorphism (SSCP) analysis, and DNA sequencing, we examined the cDNA structure of the Fas antigen in 54 bone marrow (BM) specimens obtained from myeloma patients. Six patient specimens (11%) did not express detectable levels of Fas antigen mRNA. Of the 48 BM specimens which did express Fas antigen, 5 (10%) displayed point mutations. All of the mutations identified were located in the cytoplasmic region of the Fas antigen known to be involved in transduction of an apoptotic signal. Two separate individuals demonstrated an identical mutation at a site previously shown to be mutated in the congenital autoimmune syndrome, ALPS. One patient exhibited a point mutation at a site only two amino acids removed from the documented lesion of the lprcg mouse. Although the functional status of these point mutations remains to be determined, we propose that Fas antigen mutations may contribute to the pathogenesis and progression of myeloma in some patients.

Investigation of aberrant translational control of c-myc in cell lines derived from patients with multiple myeloma

In cell lines derived from patients with multiple myeloma (MM) we have found an elevation in the amount of the c-myc protein which is not accompanied by an increase in the level of mRNA or a change in the half-life of the protein. There is a 3.4 fold enhancement in the degree of association of the c-myc message with polysomes. This is not accompanied by an alteration in polysome size or a change in the transit time of the c-myc mRNA on the polysomes thus suggesting that there is in increase in the degree of mobilisation of the c-myc message. Sequencing of the c-myc 5'UTR has revealed the presence of a mutation in all the MM cell lines studied and we demonstrate that this mutation causes altered binding of cellular proteins to this RNA species.

Liposomal targeting of bcl-2 antisense oligonucleotides with enhanced stability into human myeloma cell lines

Cationic liposomes improve the delivery of antisense oligonucleotides (ODNs) into cells. However, there is marked variability in the cellular uptake of ODNs into different cell lines. We used liposomes containing dimethyloctadecylammonium bromide (DDAB) and dioleoylphosphatidylethanolamine (DOPE) to increase the delivery of phosphodiester ODNs into four different myeloma cell lines. The delivery by cationic liposomes increased the delivery of bcl-2 antisense ODNs by a factor of 9 to 45 as compared to plain ODNs. The stability of ODNs was increased with liposomes both in the culture medium and within the cells. Intact liposomal ODNs were detected inside the cells up to 24 hours with gel electrophoresis and phosphor imager analysis. Antisense ODNs had no effect on bcl-2 mRNA levels. Also the proliferation of myeloma cells remained unchanged during the 3-day incubation period. Our study shows that liposomal antisense ODNs targeting bcl-2 of human myeloma cells result in increased stability of ODNs with minimal toxicity. However, further modifications are needed to gain biological effects of antisense ODNs on human myeloma cells.

Cytokines in tumour growth, migration and metastasis

A wide variety of cytokines are involved at every stage of tumour growth and dissemination. Primary tumour growth is helped by growth factors and angiogenic factors. These may either be produced by tumour cells themselves or be provided by one of the infiltrating cell populations, such as vascular endothelium or leukocytes. The influx of these cells is, in turn, under the control of the chemokines, a chemoattractant subfamily of cytokines. Autocrine motility factors, in conjunction with cytokines that regulate the production and activity of proteases capable of breaking down components of the extracellular matrix, are involved in the dispersal of cells from primary tumours, leading to the formation of metastases. The development of metastases may also be under the control of circulating cytokines released from the primary tumour. The ways in which cytokines and allied growth factors regulate tumour growth and development are both complex and controversial. However, the study of this system will provide a more profound understanding of tumour biology and may lead the way for the development of novel therapeutic approaches.

A prognostic index for multiple myeloma

The current prognostic systems have failed to identify multiple myeloma (MM) patients who require aggressive therapy. These staging systems do not reliably distinguish patients with different prognoses. This paper explores the possibility of improving the prognostic forecast in MM by considering some clinical characteristics at diagnosis together with response to first-line chemotherapy. A total of 231 patients were prospectively randomised in a multicentre trial to no therapy vs melphalan + prednisone (MP) for stage I, MP in stage II, and MP vs peptichemio, vincristine and prednisone for stage III. The clinical features of these groups were evaluated for prognostic variables predictive of overall survival by means of univariate and multivariate analysis. The independently significant variables were incorporated into a model that identified three groups of patients with different risks of death and different overall survival. Three variables retained statistical significance: the staging system proposed by the British Medical Research Council, a composite parameter integrating the percentage of bone marrow plasma cells with cytological features of the infiltrating elements (plasma cell vs plasmablast), and response to 6 months of first-line chemotherapy. These three variables led the proposal of a scoring system able to identify three different risk classes (with median overall survival of 52, 28 and 13 months respectively) and to estimate individual patient prognosis more flexibly. The proposed risk classes, drawn from both diagnostic and therapeutic parameters, are thought to be a clinical and investigational instrument for separating MM patients into comparable groups, for selecting the best available therapy and for evaluating response with respect to the disease of each new patient.

Multiple myeloma

OBJECTIVES

To review the epidemiology, pathogenesis, clinical features, diagnosis, treatment, and nursing management of multiple myeloma.

DATA SOURCES

Review articles, research studies, and book chapters related to multiple myeloma.

CONCLUSIONS

Despite insights into the immunobiology of multiple myeloma and the advances in intensive therapy and supportive care, multiple myeloma remains an incurable disease. Patients will experience chronic and acute symptomatic episodes throughout the course of their disease.

IMPLICATIONS FOR NURSING PRACTICE

Oncology nurses can assist patients with multiple myeloma and their families to manage both the disease and treatment related symptoms and to improve their overall quality of life. Specific nursing assessments can provide early recognition of complications, such as hypercalcemia and spinal cord compression.

Cell surface markers in multiple myeloma

OBJECTIVE

To describe the immunophenotype of normal and myelomatous plasma cells (PCs) and the changes in immunoregulatory nonmyelomatous cells in multiple myeloma (MM).

DESIGN

The cell surface markers (antigens) associated with this common cancer were reviewed.

MATERIAL AND METHODS

Immunophenotypic characterization of both normal PCs and their counterpart malignant hematopoietic cells can be achieved by using monoclonal antibodies and either flow cytometry or immunocytochemical techniques.

RESULTS

Normal PCs are heterogeneous and express, in addition to cytoplasmic immunoglobulins, the antigens CD9, CD10, CD13, CD19, CD20, CD33, CD38, and D-related human leukocyte antigen (HLA-DR). This heterogeneity also occurs in malignant PCs. Myelomatous PCs may express, in addition to CD38 (the most typical PC marker), the antigens CD9, CD10, HLA-DR, and CD20. Other non-B-cell lineage markers such as myeloid (CD13, CD14, CD15, CD33, CD41, and glycophorin A), T-cell (CD2 and CD4), and natural killer-associated (CD56) antigens, as well as CD23, CD24, CD25, CD37, CD39, CDw40, CD45R, CD71, and certain unclustered antigens (R1-3, PCA-1, PCA-2, PC1, 62B1, 8A, 8F6, and MM4), have been noted in myelomatous PCs. The presence of these antigens in the myeloma cells may have a prognostic value--for example, the expression of CD20 and of myelomonocytic antigens (CD11b, CD13, CD14, CD15, and CD33) may be related to a poor prognosis. The adverse prognostic implication of the expression of CD10 initially described in MM has not been subsequently confirmed. Patients with MM may have mononuclear cells in their peripheral blood that express the same antigens as those expressed by the myeloma cells in their bone marrow. The presence of such cells or their therapy-associated decrease or disappearance may be related to the prognosis of patients with MM.

CONCLUSION

The presence of cell surface markers on PCs and their prognostic significance in patients with MM warrant further investigation.