ALK-positive extramedullary plasmacytoma with expression of the CLTC-ALK fusion transcript.

Anaplastic lymphoma kinase (ALK)-positive non-Hodgkin lymphoma (NHL) was long thought to be a disease occurring uniquely in T or null-cell lymphomas. More recently, however, a small number of B-lineage lymphomas have been reported to express ALK fusion genes. These tumors often exhibit a plasmablastic morphology, a finding which prompted our interest in looking for ALK fusions in plasma cell neoplasms. We studied 46 cases of extramedullary plasmacytoma by immunostaining with anti-ALK antibody and fluorescence in situ hybridization (FISH) analysis using an ALK break-apart probe and found one case to be ALK protein-positive and demonstrated the disruption of the ALK gene in this case. Immunohistochemistry showed that the tumor cells were strongly positive for CD138, VS38c, and epithelial membrane antigen, but lacked expression of CD20, CD79a, CD45, and CD30. Both RT-PCR and genomic DNA-PCR confirmed the CLTC-ALK fusion. This finding expands the lists of the ALK-positive tumors, and ALK-positive extramedullary plasmacytoma may benefit from the treatment of ALK inhibitor in the future.

Eef1a2 promotes cell growth, inhibits apoptosis and activates JAK/STAT and AKT signaling in mouse plasmacytomas.

BACKGROUND: The canonical function of EEF1A2, normally expressed only in muscle, brain, and heart, is in translational elongation, but recent studies suggest a non-canonical function as a proto-oncogene that is overexpressed in a variety of solid tumors including breast and ovary. Transcriptional profiling of a spectrum of primary mouse B cell lineage neoplasms showed that transcripts encoding EEF1A2 were uniquely overexpressed in plasmacytomas (PCT), tumors of mature plasma cells. Cases of human multiple myeloma expressed significantly higher levels of EEF1A2 transcripts than normal bone marrow plasma cells. High-level expression was also a feature of a subset of cell lines developed from mouse PCT and from the human MM. METHODOLOGY/PRINCIPAL FINDINGS: Heightened expression of EEF1A2 was not associated with increased copy number or coding sequence mutations. shRNA-mediated knockdown of Eef1a2 transcripts and protein was associated with growth inhibition due to delayed G1-S progression, and effects on apoptosis that were seen only under serum-starved conditions. Transcriptional profiles and western blot analyses of knockdown cells revealed impaired JAK/STAT and PI3K/AKT signaling suggesting their contributions to EEF1A2-mediated effects on PCT induction or progression. CONCLUSIONS/SIGNIFICANCE: EEF1A2 may play contribute to the induction or progression of some PCT and a small percentage of MM. Eef1a2 could also prove to be a useful new marker for a subset of MM and, ultimately, a possible target for therapy.

Targeting activation-induced cytidine deaminase overcomes tumor evasion of immunotherapy by CTLs.

Activation-induced cytidine deaminase (AID) is an enzyme essential for the generation of Ab diversity in B cells and is considered to be a general gene mutator. In addition, AID expression was also implicated in the pathogenesis of human B cell malignancies and associated with poor prognosis. In this study, we report that small interfering RNA silencing of AID in plasmacytoma dramatically increased its susceptibility to immunotherapy by CTLs. AID silencing did not decrease the mutation frequencies of tumor Ag gene P1A. Gene-array analysis showed dramatically altered expression of a number of genes in AID-silenced plasmacytoma cells, and upregulation of CD200 was shown to be in favor of tumor eradication by CTLs. Taken together, we demonstrate a novel function of AID in tumor evasion of CTL therapy and that targeting AID should be beneficial in the immunotherapy of AID-positive tumors.

Immunostimulatory effects of low-dose cyclophosphamide are controlled by inducible nitric oxide synthase.

Cyclophosphamide is a widely used chemotherapeutic drug that was recently applied as either an antiangiogenic/antivasculogenic or an immunostimulatory agent in combination with cancer immunotherapies. It has been previously shown that cyclophosphamide augments the efficacy of antitumor immune responses by depleting CD4+ CD25+ T regulatory cells and increasing both T-lymphocyte proliferation and T memory cells. Furthermore, cyclophosphamide was shown to mediate killing of circulating endothelial progenitors. However, the molecular basis for these observations has not yet been elucidated. We show here that the cyclophosphamide-mediated inhibition of inducible nitric oxide synthase is directly linked to its immunostimulatory but not to its antivasculogenic effects. Moreover, combined application of cyclophosphamide with a novel, oral DNA vaccine targeting platelet-derived growth factor B (PDGF-B), overexpressed by proliferating endothelial cells in the tumor vasculature, not only completely inhibited the growth of different tumor types but also led to tumor rejections in mice. These findings provide a new rationale at the molecular level for the combination of chemotherapy and immunotherapy in cancer treatment.

The cytoplasmic trafficking of DNA topoisomerase IIalpha correlates with etoposide resistance in human myeloma cells.

In this study we have investigated the role of topoisomerase (topo) IIalpha trafficking in cellular drug resistance. To accomplish this, it was necessary to separate the influence of cell cycle, drug uptake, topo protein levels, and enzyme trafficking on drug sensitivity. Thus, we developed a cell model (called accelerated plateau) using human myeloma H929 cells that reproducibly translocates topo IIalpha to the cytoplasm. Compared to log-phase cells, the cytoplasmic redistribution of topo IIalpha in plateau-phase cells correlated with a 10-fold resistance to VP-16 and a 40-60% reduction in the number of drug-induced double-strand DNA breaks. In addition, 7-fold more VP-16 was necessary to achieve 50% topo IIalpha band depletion, suggesting that there are fewer drug-induced topo-DNA complexes formed in quiescent cells than in log-phase cells. The total cellular amount of topo IIalpha and topo IIbeta protein in log- and plateau-phase cells was similar as determined by Western blot analysis. There was a 25% reduction in S-phase cell number in plateau cells (determined by bromodeoxyuridine (BrdU) incorporation), while there was no significant difference in the equilibrium concentrations of [(3)H]-VP-16 when log cells were compared with plateau cells. Furthermore, the nuclear/cytoplasmic ratio of topo IIalpha is increased 58-fold in accelerated-plateau H929 cells treated with leptomycin B (LMB) when compared to untreated cells. It appears that the nuclear-cytoplasmic shuttling of topo IIalpha, which decreases the amount of nuclear target enzyme, is a major mechanism of drug resistance to topo II inhibitors in plateau-phase myeloma cells.

Disruption of transforming growth factor beta signaling by a novel ligand-dependent mechanism.

Transforming growth factor (TGF)-beta is the prototype in a family of secreted proteins that act in autocrine and paracrine pathways to regulate cell development and function. Normal cells typically coexpress TGF-beta receptors and one or more isoforms of TGF-beta, thus the synthesis and secretion of TGF-beta as an inactive latent complex is considered an essential step in regula-ting the activity of this pathway. To determine whether intracellular activation of TGF-beta results in TGF-beta ligand-receptor interactions within the cell, we studied pristane-induced plasma cell tumors (PCTs). We now demonstrate that active TGF-beta1 in the PCT binds to intracellular TGF-beta type II receptor (TbetaRII). Disruption of the expression of TGF-beta1 by antisense TGF-beta1 mRNA restores localization of TbetaRII at the PCT cell surface, indicating a ligand-induced impediment in receptor trafficking. We also show that retroviral expression of a truncated, dominant-negative TbetaRII (dnTbetaRII) effectively competes for intracellular binding of active ligand in the PCT and restores cell surface expression of the endogenous TbetaRII. Analysis of TGF-beta receptor-activated Smad2 suggests the intracellular ligand-receptor complex is not capable of signaling. These data are the first to demonstrate the formation of an intracellular TGF-beta-receptor complex, and define a novel mechanism for modulating the TGF-beta signaling pathway.

Expression and induction of collagenases (MMP-8 and -13) in plasma cells associated with bone-destructive lesions.

Matrix metalloproteinases (MMPs) collectively degrade extracellular matrix and basement membrane proteins in chronic inflammation and bone-destructive lesions. This study examined the ability of immunoglobulin-producing plasma cells, typically present in sites of chronic inflammation, to express collagenases (MMP-8 and -13) in vivo and in vitro. Phorbol-12-myristate-13-acetate, interleukin-6, and tumour necrosis factor-alpha and heparin with the tumour promoter or cytokines potently enhanced (up to nine-fold) MMP-8 and -13 expression by the RPMI 8226 myeloma cell line, as evidenced by western blotting and semi-quantitative reverse transcriptase-polymerase chain reaction. Immunohistochemical analysis and in situ hybridization revealed that plasma cells expressed MMP-8 and -13 focally in periapical granulomas, odontogenic cysts, and malignant plasmacytomas. MMP-8 and MMP-13 from plasma cells can participate in bone organic matrix destruction at sites of chronic inflammation and neoplastic growth. Since MMP-13 was more frequently expressed than MMP-8 in plasma cells of strongly recurring keratocysts and malignant plasmacytomas, it is concluded that plasma cell MMP-13 has a particularly important role in benign and malignant bone-destructive lesions.

IgD multiple myeloma preceding the development of extensive extramedullary disease without medullary involvement.

We present a unique case of IgD multiple myeloma (MM) preceding the development of extensive extramedullary disease without medullary involvement. A 63-year-old man was diagnosed with IgD-lambda MM when he developed anemia. After 3 months of chemotherapy, he was in complete remission as evidenced by the disappearance of bone marrow (BM) plasmacytosis, monoclonal IgD protein in his serum, and Bence Jones proteinuria. Six months after diagnosis, his disease took an unusual course with the development of plasmacytomas in the skin, without medullary involvement. He then received chemotherapy, resulting in the complete disappearance of the subcutaneous plasmacytomas. Two years after the initial diagnosis, his disease took an aggressive clinical course with retroperitoneal relapse, leading to the patient's death within 1 month. The two separate episodes of extramedullary disease were associated with elevated serum lactic dehydrogenase levels and the absence of plasma cells in the BM. This case provides evidence of two separate transformations of the original malignant MM clone.

The phosphatidylinositol 3-kinase/AKT kinase pathway in multiple myeloma plasma cells: roles in cytokine-dependent survival and proliferative responses.

Interleukin 6 (IL-6) and insulin-like growth factor I (IGF-I) induce proliferative and antiapoptotic responses in multiple myeloma (MM) plasma cells. Because these cytokines may activate the phosphatidylinositol 3-kinase (PI 3-K)/AKT kinase pathway in other cell types, we investigated the role of PI 3-K/AKT in MM cell responses. IGF-I effectively activated PI 3-K in 8226 and OCI-My5 MM cells, but IL-6 was ineffective. However, IL-6 successfully activated PI 3-K in AF-10 MM cells and IL-6-dependent MH.60 plasmacytoma/hybridoma cells. IGF-I also successfully activated PI 3-K in four of four MM patient specimens, and IL-6 activated PI 3-K in three of four specimens. Inhibition of PI 3-K activity with wortmannin or Ly294002 blocked the antiapoptotic effect of IGF-I and the proliferative effect of IL-6 in the myeloma cell lines. Furthermore, a dominant negative PI 3-K construct, expressed in AF-10 cells by adenoviral infection, also significantly inhibited the IL-6 proliferative response in MM cells. In correlation with activation of PI 3-K, IGF-I also effectively activated the AKT kinase in 8226 and OCI-My5 cells, and IL-6 activated AKT in AF-10 and MH.60 cells. However, although incapable of activating PI 3-K in 8226 and OCI-My5 cells, IL-6 successfully activated AKT in these MM lines, suggesting PI 3-K-independent mechanisms of AKT activation. The prevention of a myeloma cell proliferative response resulting from inhibition of PI 3-K activity was not associated with an inhibition of IL-6-dependent extracellular signal-regulated kinase (ERK) activation. These results support a role for the PI 3-K/AKT pathway in cytokine-dependent responses in myeloma cells, which is independent of any activation of the ERK pathway.

BALB/c.CBA/N mice carrying the defective Btk(xid) gene are resistant to pristane-induced plasmacytomagenesis.

The X-chromosome from the CBA/N mouse which carries the defective Bruton's tyrosine kinase (Btk) allele (Xxid) has been introgressively backcrossed onto the plasmacytoma (PCT) induction-susceptible BALB/cAN. Inbred BALB/c.CBA/N-xid/xid (C.CBA/N) mice raised and maintained in our conventional colony were given three 0.5 ml injections of pristane and were highly refractory to PCT induction. Only one PCT was found among 59 mice followed for > or =300 days. Twenty mice were examined at day 200 for foci of plasma cells in the oil granuloma. Ten mice had small foci of plasma cells, most of which were plasmacytotic, embedded in the inflammatory oil granuloma. In one there were multiple foci, but most of the mice had only one or two foci. F1 hybrid XxidY males derived from CBA/N females crossed to BALB/cAnPt were also resistant to PCT induction, while heterozygous and homozygous XY males were susceptible. C.CBA/N mice can develop extensive mucosal plasma cells as well as plasma cell accumulations in oil granuloma tissue, but the precursors of these plasma cells do not give rise to PCT in genetically susceptible hosts. The failure of C.CBA/N mice to develop PCT is probably due to the elimination of B cell clones that can be perpetuated by repeated exposure to thymus-independent type 2 antigens.

Inducible expression of the beta 1 subunit of the sodium pump.

The Na,K-ATPase, or sodium pump, a ubiquitous transmembrane enzyme in higher eukaryotes, consists of an alpha and a beta subunit. Here we investigate the expression pattern of the two beta isotypes in mouse B cell lines. Neither primary cells nor cell lines express beta 2. Abelson virus-transformed pre-B cells express beta 1, while B lymphomas and plasmacytomas do not. Thus, beta 1 expression in transformed cells follows that of their untransformed counterparts. Some subclones of pre-B cell line 70Z/3 express beta 1, and others do not, but lipopolysaccharide induces the beta 1-negative cells to become beta 1-positive.

The expression of lysozyme in multiple myeloma.

Lysozyme, a hitherto myelomonocytic marker, has been previously reported as being raised in the sera of some myeloma patients. This fact, and the sporadical observation of a positive immunohistochemical lysozyme staining seen in some myelomas, prompted us to systematically search for an expression of lysozyme in both neoplastic and reactive plasma cells. A total of 74 paraffin-embedded, formalin-fixed, EDTA-decalcified core biopsies of newly diagnosed cases of plasmacytoma were immunohistochemically investigated for lysozyme expression by a modified avidin-biotin immunoperoxidase technique. The myelomas were subclassified according to their nuclear maturity into poorly differentiated plasmacytoma (PDP) (30 cases), moderately differentiated plasmacytoma (MDP) (24 cases), and well differentiated plasmacytoma (WDP) (20 cases). An unexpected lysozyme positivity was seen in 16/74 cases, and was most prevalent in 10/30 cases of PDP. No correlation has been detected between either lysozyme and kappa or lambda light chain expression, or an abnormal activity of chloroacetate esterase sometimes seen in myeloma. Since lysozyme has not been found in normal plasma cells or reactive plasmacytosis, the expression of this antigen in myeloma represents another example of so-called lineage infidelity, and parallels the previously reported abnormal expression of other myelomonocytic markers in some myelomas and a myeloma cell line. Apart from the unsettled prognostic impact, a facultative lysozyme expression in myeloma must be always considered when applying algorhythmic immunohistological strategies in delineating the histogenesis of haematopoietic or lymphatic malignancies.

Cytoplasmic poly(ADP-ribose)polymerase from mouse plasmacytoma free messenger ribonucleoprotein particles: purification and characterization.

A cytoplasmic poly(ADP-ribose)polymerase (PARP) was purified from mouse plasmacytoma free messenger ribonucleoprotein particles using chromatography on 3-aminobenzamide affigel-10. The purified protein showed one band at 116 kDa on SDS-polyacrylamide gel electrophoresis and shared similar antigenic sites to the nuclear PARP. An apparent Km for NAD of 100.5 +/- 6.3 microM and a Vmax of 174 +/- 40 nmoles of ADP-ribose incorporated/min/mg protein were observed. RNA was detected in the enzyme preparation and the enzymatic activity was not DNA dependent.

IgG-kappa-type plasmacytoma secreting salivary-type amylase in adult T-cell leukemia.

A IgG-kappa-type plasmacytoma secreting salivary-type amylase ectopically is reported in a patient with smouldering adult T-cell leukemia(ATL). The patient had plasmacytomas in the distal region of the right femur, the proximal region of left tibia, and the left paranasal sinus. Both his serum and urine contained high levels of amylase. The presence of IgG-kappa and S-type amylase in the plasmacytoma cells was confirmed immunocytochemically. In addition, he was also positive for the antibody against the human T-cell leukemia virus type I (HTLV-I), and had abnormal lymphocytes with convoluted nuclei (ATL cells) in the peripheral blood. The monoclonal integration of HTLV-I proviral DNA was demonstrated in the leukemic cells of the peripheral blood, but not in the plasmacytoma cells. Our case suggested that not only can HTLV-I infection play a role in the development of ATL, but may also induce a B-cell malignancy in an indirect manner, and even an ectopic amylase producing plasmacytoma.

Immunohistochemical studies of beta-hexosaminidase in neoplastic and normal tissues with monoclonal antibodies.

A total of 87 human specimens with 10 histological types of primary neoplasm were studied immunohistochemically with monoclonal antibodies specific for beta-hexosaminidase (Hex). High levels of Hex were found in malignant neoplasms of the skin, cervix, colorectum and in benign as well as neoplastic plasma cells, while no activity was detected in normal epidermis, normal colorectal epithelium or benign naevi. The strongest immunohistochemical reaction was revealed in tumor cells of malignant melanoma. Adenomas and adenocarcinomas of the colorectum showed high levels of Hex with a basal pattern of immunoreactivity more frequent in the tumor cells of adenocarcinomas than adenomas. Fibroblasts and macrophages in the tumors often disclosed immunoreactivity. In most of the sections (including those from plasma cell neoplasms), 7E4 antibody showed low immunoreactivity compared to 2E3, except for non-neoplastic plasma cells, which were as a rule positive with 7E4 and largely negative with 2E3 antibody. This result probably indicated different isoenzymes in benign and neoplastic plasma cells.

The activities of aminoacyl-tRNA synthetase phosphatase and aminoacyl-tRNA synthetases in MPC-11 and Krebs II ascites cells.

The activity of aminoacyl-tRNA synthetase phosphatase as well as the activities of aminoacyl-tRNA synthetases in Krebs II ascites cells and MPC-11 cells have been investigated. The activity of the phosphatase was greater in the tumor cells than in normal tissues. The aminoacyl-tRNA synthetase activities were 100-300 times higher than the activities found in the uterus of ovariectomized mice, but not very different from the activities found in the liver. The influence of cyclic AMP. 2-deoxyadenosine 3-phosphate and 2-deoxyguanosine 3-phosphate on the growth of MPC-11 cells, grown in suspension culture, was also investigated.

Modulation of nucleotide pyrophosphatase in plasmacytoma cells.

The effect of glucocorticoid hormones on the protein responsible for both nucleotide pyrophosphatase (EC 3.6.1.9) and alkaline phosphodiesterase I (EC 3.1.4.1) activities was examined in murine MOPC 315 plasmacytoma cells. Incubation of these cells with dexamethasone resulted in parallel increases in pyrophosphatase and phosphodiesterase specific activities. The incorporation of [3H]mannose into N-linked oligosaccharide precursors was also analyzed in cells following hormone modulation. In cells treated for 36 hours or cultured continuously with dexamethasone, the resulting increase in enzyme specific activities was accompanied by a decrease in [3H]mannose incorporation, consistent with the hypothesis that in some cell types, nucleotide pyrophosphatase activity is involved in the regulation of glycoprotein synthesis.

The enzymology of apurinic/apyrimidinic endonucleases.

Studies on the enzymology of apurinic/apyrimidinic (AP) endonucleases from procaryotic and eucaryotic organisms are reviewed. Emphasis will be placed on the enzymes from Escherichia coli from which a considerable portion of our knowledge has been derived. Recent studies on similar enzymes from eucaryotes will be discussed as well. In addition, we will discuss the chemical and physical properties of AP sites and review studies on peptides and acridine derivatives which incise DNA at AP sites.

Amylase-producing plasmacytoma cell lines, AD3 and FR4, with der(14)t(8;14) and dic(8)t(1;8) established from ascites.

We established two human plasma cell lines, FR4 and AD3, from ascitic fluid in a patient with IgA k plasmacytoma (PC). Aberrant amylase production was found in this patient. Both AD3 and FR4 were free of Epstein-Barr virus, and both produced Ig A k in vitro. They produced amylase of the salivary type in vitro. This was confirmed by the demonstration of amylase mRNA comigrating with salivary gland mRNA. These cell lines commonly had unusual chromosomal abnormalities der(14)t(8;14) and dic(8)t(1;8). AD3 had additional chromosomal abnormalities compared with FR4. This suggests that AD3 is a subline of FR4. The oncogene c-myc is rearranged in most case of Burkitt's lymphoma with t(8;14). However, neither rearrangement nor amplification of the c-myc allele was detected in our PC lines. These lines expressed c-myc of 2.4 kb. There were no structural changes in the amylase genes of AD3 and FR4 detectable with Southern blotting analysis. As these lines were authentic PC lines, they would be useful for the future study of the relationship between the mechanism of oncogenesis and the rare tumor aberration, amylase production.

[Amylase-producing extramedullary plasmacytoma with multiple cutaneous metastasis following a solitary plasmacytoma of bone].

A 65-year-old woman was admitted because of multiple cutaneous tumors in the left lumbar area in March 1983. In 1979, she had been diagnosed as solitary plasmacytoma (IgG, kappa) of the left femur and amputation of the left leg had been performed. In 1981, the tumor relapsed in the left ilium in association with an increased level of serum IgG with M-component and normal activity of serum amylase. The serum M-protein had been disappeared after resection of the tumor. On admission laboratory examinations showed a slightly high level of serum IgG and elevated activities of serum and urine amylase. Amylase isoenzyme analysis revealed a predominance of the S-isozyme. Bone marrow aspiration revealed no atypical plasma cells. The supernate of cultured plasma cells obtained from the cutaneous tumor contained high amylase activity consisting exclusively of S-type. Thereafter serum amylase activities changed approximately in parallel with serum M-protein levels and total tumor volumes after chemotherapy or radiotherapy. At the terminal phase in 1986, however, serum amylase activities became extraordinarily high compared with serum M-protein levels, suggesting a clonal change of the plasmacytoma cells.