Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the present study, we demonstrate that the PKC-activating phorbol ester PMA selectively induced IgA synthesis by PP B cells. PKC activation triggered neither B cell proliferation nor the switching rate of IgA- to IgA+ cells. Together with the fact that the rate of IgA secretion by the myeloma cell line MOPC 315 was not altered by PMA, the data demonstrate that activation of PKC enhances IgA secretion by promoting terminal differentiation of IgA-committed B cells into IgA-secreting plasma cells.
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PMID:Role for protein kinase C activation in IgA B cell terminal differentiation. 195 71

In the present study a rat leukemia NK cell line designated CRC- (derived from RNK-16 cells) was shown to spontaneously transform into a noncytolytic (NL) line referred to as CRC-/NL cells. CRC- and CRC-/NL cells were utilized to study pathways of NK activation by phorbol esters, calcium ionophore (A23187), and monoclonal antibody (mAb). 10(-6)-10(-7) M phorbol myristate acetate (PMA) but not phorbol didecanoate or 4-beta-phorbol activated CRC-/NL to lyse YAC-1 targets. Activated CRC-/NL cells produced 20-90% specific cytotoxicity compared to 0-5% for nonactivated cells. 10(-7) M PMA inhibited normal CRC- cytotoxicity. The optimum concentration of PMA for activation was 10(-6)-10(-7) M and 3-6 h treatment time. Augmentation of cytotoxicity by PMA occurred at different E:T ratios. The time required to reverse the PMA activation of CRC-/NL cells was approximately 9-10 h posttreatment. In an effort to attempt to differentiate pathways which initiated activation, CRC-/NL cells were treated with FAM binding mAb, or with combinations of mAb and ionophore, mAb and PMA, or PMA and A23187. mAb singly or in combination with 10(-7) M PMA increased cytotoxicity. However, A23187 either singly or when combined with PMA or mAb did not produce an augmented lysis of YAC-1 target cells. Additional experiments were conducted to determine if PMA activation was associated with FAM binding. This was accomplished by analyzing redirected killing of various FAM mAb-producing myeloma cells in the presence of 10(-7) M PMA. PMA treatment of the CRC-/NL cells caused a significant increase in the lysis of myeloma/mAb-producing cells compared to control cells. Further evidence that FAM binding was associated with cytotoxicity was presented by demonstrating specific inhibition of redirected lysis by homologous mAb. Phenotype analysis of CRC- and CRC-/NL cells demonstrated that OX-7 and OX-1 expression on CRC-/NL cells was increased by 71.8 and 86.8% respectively compared to CRC-. FAM expression (78-83% positives) by CRC- and CRC-/NL cells was not different. These experiments indicated at the functional level that rat NK cells can be activated for increased cytotoxicity by FAM-specific mAb binding and/or by treatment with the diacylglycerol analogue PMA. This implies that protein kinase C mobilization either singly or in concert with inositol-1,4,5-trisphosphate activation following FAM mAb binding may play important roles in NK cell cytotoxicity.
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PMID:Detection of function-associated molecules on rat leukemic NK cells: activation by monoclonal antibody or phorbol ester. 208 44

Protein kinase C activity of the human myeloma cell line, RPMI 8226, was studied after prepurification on DEAE-cellulose. The total protein kinase activity, eluted at 0.12 M NaCl, was 493 nmol/min/10(10) cells, but 38% was associated with membranes. The lipid dependence of cytosolic and membrane activities was only 52% and 21%, respectively. This activity increased with time, to as much as 200% for the membrane fraction after 7 days, whereas lipid dependence and the PDBu binding properties were lost. This modified activity was not due to the extinction of a copurifying endogenous inhibitor nor to classical PKC proteolysis. TPA-treatment of these cels is accompanied by a rapid, selective and complete loss of lipid-dependent activity of the cytosol, thus benefiting co-migrating lipid independent activity, with no membrane fraction recovery or PKM formation.
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PMID:Abnormal behavior of protein kinase C in the human myeloma cell line, RPMI 8226. 240 58

Studies of an EBV-transformed and TNP-specific human B cell line revealed that, unlike myeloma or hybridoma cell lines that consist mainly of fully differentiated cells, most of the cloned EBV-transformed cells were not fully differentiated, as judged by inability to bind TNP-SRBC and to secrete anti-TNP antibody. The minority of more differentiated cells were selected by TNP-SRBC rosetting. They were found to proliferate to a lesser extent than nonrosetting cells and to contain increased numbers of antibody-secreting cells. This inverse relationship between proliferation and differentiation was also shown to be cell cycle related in that the TNP-SRBC rosetting cells resided, to a greater extent than the nonrosetting cells, in the G1 phase of the cell cycle. The finding that the G1 phase of the cell cycle was associated with differentiation into anti-TNP secreting cells was confirmed by demonstrating that treatment with hydroxyurea, which arrests the cells in G1, resulted in decreased proliferation and an increased proportion of antibody-secreting cells. Similarly, addition of phorbol ester resulted in increased antibody secretion and decreased proliferation, suggesting a role for protein kinase C in this differentiation pathway. The strategy of increasing the number of antibody-producing cells in this human EBV line, by promoting differentiation of the cells in G1, may be relevant to the large scale production of specific human mAb for the treatment and diagnosis of human diseases.
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PMID:Inverse relationship between proliferation and differentiation in a human TNP-specific B cell line. Cell cycle dependence of antibody secretion. 245 17

The effect of phorbol esters and mezerein pretreatment on macrophage (M phi) activation for tumor cytolysis, tumor necrosis factor (TNF) secretion, and TNF-alpha mRNA expression was investigated. Following pretreatment with various concentrations (0.01 to 10 micrograms/ml) of phorbol 12-myristate 13-acetate (PMA), phorbol-12,13-dibutyrate (PDBu), or mezerein for 16 h, murine peritoneal M phi were activated with M phi-activating factor (MAF) or calcium ionophore A23187 and tested for cytotoxicity in a 24-h cytolysis assay against 125-I-UdR-labeled P815 mastocytoma and NS-1 myeloma target cells. It was found that pretreatment with all three protein kinase C (PKc) activators inhibited M phi activation for cytotoxicity against P815 cells in a dose-dependent manner. Fifty percent inhibition was achieved at concentrations less than 0.1 micrograms/ml. The inhibition was partially reversible. In contrast, the pretreatment did not at all inhibit but significantly enhanced M phi activation for cytolysis against NS-1 cells. Furthermore, exposure to PMA augmented M phi activation by MAF and A23187 for TNF secretion upon stimulation with trace amounts of lipopolysaccharide (LPS). Although the pretreatment neither enhanced nor significantly reduced the synergistic effect of MAF and A23187 on TNF-alpha mRNA expression, it did increase the expression stimulated by LPS alone. Finally, the PKc activity in M phi treated with PMA, PDBu, and mezerein was down-regulated to about 10% of control. Taken together, our results suggest that: 1) PKc plays an important role in the transduction of activating signals for M phi activation by MAF and A23187 to mediate cytotoxicity against some (P815) but not other (NS-1) tumor cells, 2) the induction of TNF-alpha mRNA expression and TNF secretion may be achieved via a PKc-independent pathway, and 3) M phi are equipped with more than one signal transduction pathways for affecting distinct functional activities.
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PMID:Effects of pretreatment with protein kinase C activators on macrophage activation for tumor cytotoxicity, secretion of tumor necrosis factor, and its mRNA expression. 261 73

A panel of 164 continuous human leukemia-lymphoma cell lines was analyzed for expression of c-kit using Northern blotting and reverse transcriptase-polymerase chain reaction (RT-PCR). The c-kit transcripts were detectable in cell lines assigned to the myeloid (in 7 of 29 by Northern blotting and in 4 of 8 by RT-PCR), monocytic (in 1 of 24 by Northern blotting and in 3 of 6 by RT-PCR), erythroid (in 6 of 8 by Northern blotting and in 5 of 5 by RT-PCR), and megakaryoblastic (in 10 of 10 by Northern blotting) lineages, c-kit expression was not seen by Northern blotting or RT-PCR analysis in any of the 93 lymphoid leukemia, myeloma, or lymphoma cell lines. Treatment of four megakaryoblastic cell lines with protein kinase C activators (phorbol ester 12-O-tetradecanoylphorbol 13-acetate and Bryostatin 1) led to terminal differentiation as assessed by morphologic alterations, changes in the surface marker profile, and growth arrest. These effects were associated with enhanced c-kit mRNA expression. Exposure to all-trans retinoic acid down-regulated c-kit mRNA levels, while simultaneously causing morphologic alterations in all four cell lines. Stimulation with growth factors (interleukin-3, granulocyte macrophage-colony stimulating factor, and insulin-like growth factors I and II), used to assess any role of c-kit in proliferative processes, did not lead to significant upregulation or downregulation of c-kit expression. The finding of constitutive and high expression of c-kit mRNA in all megakaryoblastic leukemia cell lines and its modulation by various reagents might further contribute to the understanding of megakaryopoietic proliferation, differentiation, and leukemogenesis.
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PMID:c-kit expression in human megakaryoblastic leukemia cell lines. 751 41

Annexin VIII is a calcium- and phospholipid-binding protein with anticoagulant activity. Annexin VIII mRNA was found to be specifically expressed in acute promyelocytic leukemia (APL) cells; it was not found in other types of acute myeloid leukemia (AML) nor in lymphoid malignancies. Using Northern blot analysis we investigated annexin VIII expression in 142 continuous human leukemia and lymphoma cell lines at the mRNA level. While the only APL cell line, NB-4, was indeed positive, other cell lines also displayed annexin VIII mRNA: 4/22 myeloid cell lines, 8/23 monocytic cell lines, 2/8 megakaryoblastic cell lines, 5/26 lymphoma-derived cell lines, 2/10 myeloma cell lines and 1/44 lymphoid leukemia cell lines. The strongest expression was seen in NB-4 and in the Hodgkin's disease derived cell line HDLM-2. Treatment of NB-4 cells with all-trans retinoic acid (ATRA) or the phorbol ester TPA induced terminal differentiation and down-regulated annexin VIII mRNA expression rapidly within a few hours; vitamin D3 was ineffective in this regard; the protein kinase C activator Bryostatin 1 up-regulated the expression. A panel of initially negative cell lines could not be induced by any of these biomodulators to transcribe annexin VIII. The half-life (T1/2) of annexin VIII mRNA was about 3-4 h using actinomycin D as transcription inhibitor. Treatment with ATRA or TPA prior to exposure to actinomycin shortened the T1/2 to 2 h while Bryostatin 1 extended it to 6h. As 21/141 non-APL cell lines were positive, annexin VIII cannot be used as a marker gene for APL cells; however, it might be associated with myelomonocytic or erythro-megakaryoblastic precursor cells. Annexin VIII gene expression might play a unique role in the proliferation and/or differentiation of leukemic cells and could be associated with the particular abnormal hemostasis of some leukemias.
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PMID:Expression and modulation of annexin VIII in human leukemia-lymphoma cell lines. 823 Dec 35

Myeloperoxidase (MPO) is found exclusively in the azurophilic granules (primary lysosomes) of normal myelomonocytic cells. Cytochemical staining for MPO activity is used clinically to distinguish myeloid from lymphoid leukemias. We studied the expression of MPO at the RNA and protein level in 140 continuous human leukemia-lymphoma cell lines using classical cytochemistry, immunofluorescent staining with a specific monoclonal antibody, Northern blot analysis, and a reverse transcription-polymerase chain reaction (RT-PCR) amplification assay. Seventy-eight lymphoid leukemia, myeloma, and lymphoma cell lines were negative; only 3 pre-B-acute lymphoblastic leukemia (ALL) cell lines were MPO-positive. Two of these MPO-positive pre-B-ALL cell lines showed a trace expression after RT-PCR and Southern blotting corresponding to 4% to 6% of the transcripts found in other positive myeloid cell lines. The third pre-B-ALL cell line was positive in Northern blots and cytochemical/immunofluorescent staining; however, only few cells were weakly positive in the latter assay. Although 15 of 59 cell lines assigned to the myeloid, monocytic, megakaryocytic, or erythroid lineages were MPO-positive in Northern blots, those 15 and 13 additional cell lines showed bands of mRNA after RT-PCR. MPO protein was detected in all 16 Northern-positive cell lines; on the other hand, there were 4 cell lines that were protein-positive, but Northern-negative. Differentiation induced by protein kinase C activators 12-O-tetradecanoylphorbol 13-acetate and Bryostatin 1 or by all-trans retinoic acid was associated with a decrease in MPO mRNA in all 7 initially positive cell lines studied, even leading to the complete absence of transcripts, but the enzymatic activity of the differentiated cells was only slightly less than that of unstimulated cells. MPO expression could not be induced in 10 initially negative cell lines. The half-life of MPO mRNA was found to be about 6 hours and was not shortened by prior exposure of the cells to the differentiation-inducing agents. These results confirm that MPO expression is mainly associated with myelomonocytic cells, but also underline the notion that MPO cannot be used as an absolutely lineage-specific marker for the distinction of leukemic cells. MPO can be used as an excellent parameter to characterize the various stages of normal and induced differentiation.
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PMID:Myeloperoxidase: expression and modulation in a large panel of human leukemia-lymphoma cell lines. 839 12

Interleukin-6 (IL-6) is one of the most important growth factors for myeloma cells. We examined the effect of recombinant IL-6 on the proliferation of five human myeloma cell lines, which were independently established AT Kawasaki Medical School. Only the KMS-11 cell line among these five lines showed growth enhancement induced by IL-6. Based on the results, a possible contribution of Ca(2+)-phospholipid-dependent protein kinase C (PKC) to the signal transduction in KMS-11 cells during growth enhancement was studied, since PKC may play an important role in malignant transformation or cell proliferation induced by some growth factors, such as IL-6. When exogenous IL-6 was added to KMS-11 culture, we observed (1) reduction of total PKC activity, and (2) translocation of PKC activity from its cytosol fraction to the membrane fraction. These findings may indicate that down regulation of PKC occurred during the myeloma cell proliferation induced by IL-6. However, IL-6 does not appear to be involved in cell proliferation and differentiation in the other cell lines studied.
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PMID:Down regulation of protein kinase C during growth enhancement induced by interleukin-6 on a human myeloma cell line, KMS-11. 891 77

The Apo-1/Fas (CD95) antigen is known to be involved in the process of T cell-mediated target cell killing and has recently been shown to be expressed on myeloma cell lines and native malignant plasma cells. Several cytokines have been reported to interfere with spontaneous and even Apo-1/Fas-induced apoptosis, but no attempt has been made yet to investigate these interactions and the possible underlying mechanisms in myeloma cells. Since in myeloma patients Interferon (IFN)-alpha2 displays a profound therapeutic effect in vivo, which is usually attributed to its growth inhibitory and/or immunomodulatory capacity, we set out to study the potential interference of IFN-alpha2 with Apo-1/Fas-induced apoptosis. Contrary to expectations, IFN-alpha2 reduced the degree of apoptosis caused by the treatment of five Apo-1/Fas-sensitive myeloma cell lines with a Fas monoclonal antibody (mAb). Simultaneous application of IFN-alpha2 and Fas mAb was superior to the prolonged (i.e. >8 h) preincubation with the cytokine as far as inhibition of Apo-1/Fas-induced apoptosis was concerned. This effect of IFN-alpha2 was neither explained by a down-regulation of the Apo-1/Fas receptor nor caused by modulation of the expression levels of c-myc, bcl-2-, bcl-xL, bax- or p53 genes. IFN-alpha2 did not alter the Apo-1/Fas-induced activity of Mitogen-activated protein kinase (MAPK) 1 and did not inhibit the Apo-1/Fas-mediated proteolytic cleavage of ADP-ribosyltransferase, a substrate of Interleukin-beta1 converting enzyme (ICE) and homologues. However, activation of protein kinase C (PKC) by phorbol 12-myristate 13-acetate (PMA) mimicked the effects of IFN-alpha2. Furthermore, the bis-indolylmaleimide GF 109203X, a specific inhibitor of PKC, inhibited the effect of PMA as well as that of IFN-alpha2 on Apo-1/Fas-induced apoptosis. These results point to a PKC-dependent mechanism of transient interaction between the intracellular signaling along the IFN-alpha2 and the Apo-1/Fas pathway (downstream of MAPK signaling as well as of ICE homologues), which becomes exhausted by prolonged stimulation with the cytokine. According to our data IFN-alpha2, applied continuously and in high doses resembling the therapeutic situation in vivo, inhibits myeloma growth. However, based on the observed inhibitory effect of IFN-alpha2 on Apo-1/Fas-induced apoptosis, a partial inhibition of the natural immune surveillance on myeloma cells by endogenous IFN-alpha2 present in the bone marrow microenvironment of this malignancy should be investigated.
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PMID:Modulation of Apo-1/Fas (CD95)-induced programmed cell death in myeloma cells by interferon-alpha 2. 897 13


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