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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hairy cell leukemia (HCL) is a B-cell tumor affecting the preplasma stage of B-cell differentiation. One important feature of the disease is its exquisite sensitivity to interferon-alpha (IFN-alpha) therapy. Because we showed earlier that the CD20 molecule is consistently hyperphosphorylated in hairy cells and because previous studies showed that CD20 is involved in regulating intracytoplasmic free calcium concentrations ([Ca2+]i) in normal B lymphocytes, we measured [Ca2+]i in tumor cell samples from patients with HCL and studied the effect of IFN-alpha on this parameter. Using the Ca(2+)-sensitive fluorophore fura-2, we observed that hairy cells display a slightly but consistently higher [Ca2+]i than normal 48-hour-activated B cells or other leukemic cells. Furthermore, both in vitro preincubation of cell samples with IFN-alpha and in vivo administration of this cytokine reduced the [Ca2+]i in hairy cells. This effect was observed together with a decrease in transmembrane Ca2+ influx. However, preincubation with IFN-gamma had no effect. The in vivo correlation between the diminution of CD20 phosphorylation and [Ca2+]i in tumor cell samples from patients at the beginning of IFN-alpha therapy suggests that these two parameters are connected.
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PMID:Interferon-alpha downregulates the abnormal intracytoplasmic free calcium concentration of tumor cells in hairy cell leukemia. 138 18

Transforming growth factor-beta (TGF-beta) is known phenomenologically as a negative regulator of several functions of mouse bone marrow macrophages. The studies reported here extend this list by showing that TGF-beta can suppress cytolytic activity of mouse bone marrow culture-derived macrophages that already have become activated by IFN-gamma and LPS for tumor cell killing, as well as confirm that this cytokine can interfere with the induction of activation. Suppression was caused by a shift in the dose response curve for IFN-gamma rather than absolute inhibition; the 50% effective dose for IFN-gamma was increased approximately fourfold by treatment with TGF-beta. TGF-beta also decreased the absolute number of IFN-gamma R on the surfaces of pretreated macrophages by approximately 30 to 35%, without altering the affinity with which IFN-gamma bound. The increased concentration of IFN-gamma needed to produce the higher level of receptor occupancy explained the observed shift in the IFN-gamma dose response curve. These results suggest that TGF-beta mediates its negative regulatory effects on macrophage activation by interfering with coupling of the IFN-gamma R to the pathways that induce and maintain macrophage activation for tumor cell killing. Such effects are consistent with the view that TGF-beta is a negative regulator of macrophage activation for tumor cell killing. Because of this fact, neoplastic cells that secrete this cytokine may have a distinct survival advantage.
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PMID:Regulation by transforming growth factor-beta 1 of expression and function of the receptor for IFN-gamma on mouse macrophages. 138 70

Recently we described a cutaneous T-cell lymphoma expressing the gamma/delta T-cell receptor [5]. The patient suffering from this lymphoma showed low numbers of myeloid and T cells in peripheral blood, while B and NK cells were relatively increased. In vitro culture of the patient's bone marrow (BM) cells revealed a significant suppression of myeloid/monocyte colony formation (GM-CFU) compared with normal controls. This was not due to infiltration of the BM with lymphoma cells. We speculated that a soluble factor either secreted or induced by the lymphoma cells might be responsible for the marked suppression of hematopoiesis in this patient. From a skin biopsy with infiltrating gamma/delta T-lymphoma cells we established T-cell clones bearing the gamma/delta T-cell receptor and resembling the phenotype of the lymphoma cells. The supernatant (SN) of these gamma/delta T-cell clones reduced the number of colonies in a CFU-GM assay (using normal control BM) in comparison to SN of alpha/beta T-cell clones established from the same biopsy. This suppression was seen mainly on day 7 of culture and was not neutralized by the addition of placenta-CM. The main mediator of this suppression seems to be IFN-gamma, since it was detectable in high amounts in the SN of these gamma/delta T-cell tumor clones as well as in the serum of the patient. In addition, anti-IFN-gamma antibodies can reverse the T-cell SN-mediated suppression of CFU-GM. We conclude that high serum levels of interferon-gamma, which is secreted in high amounts from gamma/delta T-cells grown from a biopsy of a cutaneous lymphoma, can suppress hematopoiesis.
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PMID:Gamma/delta receptor-expressing T-cell clones from a cutaneous T-cell lymphoma suppress hematopoiesis. 139 Nov 20

The potential of the immune system to inhibit or stimulate tumor growth is a vivid example of the "two-edged sword" nature of immune responses. Our results provide evidence that this dual capacity can be attributed, in part, to the dual pathways of arginine metabolism exhibited by intratumor macrophages. Specifically, i.p. tumor rejection in P815-preimmunized mice is accompanied by an upshift in intratumor macrophage arginine metabolism to the nitric oxide (NO) synthase pathway that yields citrulline and NO. A rapid and marked local increase in IFN-gamma (both mRNA and protein) in preimmunized mice during tumor rejection suggests that this cytokine plays a role in up-regulating nitric oxide production in vivo. Unlike tumor rejection, progressive i.p. P815 tumor growth in naive mice is associated with a marked decline in the production of citruline/NO by intratumor macrophages. Examination of macrophage arginine metabolism via arginase revealed a pattern opposite that of NO synthase. The local production of ornithine/urea markedly increases during progressive tumor growth whereas arginase activity decreases during tumor rejection. Inasmuch as nitric oxide inhibits tumor cell replication whereas ornithine is the precursor of polyamines required for cell replication, these results are consistent with the conclusion that the pathway macrophages use to metabolize arginine can influence the type of host immune responses against cancer and other conditions.
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PMID:Macrophage arginine metabolism and the inhibition or stimulation of cancer. 140 10

Cytokine production was investigated in whole blood cell cultures from 74 patients with colorectal carcinomas, 20 patients with benign colorectal tumors, and 314 healthy controls. In the 4 day post induction supernatants the levels of IFN-gamma, IL-1-alpha, IL-2, and TNF-alpha were measured by a sensitive immunoassay. In the blood cell cultures of the patients with colorectal carcinomas significantly lower values of IFN-gamma (P less than or equal to .001), IL-1-alpha (P less than or equal to .001), and IL-2 (P less than or equal to .01) were found as compared to the patients with benign tumors and the controls, although total and differential leukocyte counts were similar in all three groups. A linear correlation between the levels of IFN-gamma and IL-1-alpha and the tumor stages could be shown. Our results suggest that a growing tumor burden may induce increasing immunological deficiencies as reflected by a decreasing cytokine production of the immune cells.
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PMID:Impaired cytokine production in whole blood cell cultures from patients with colorectal carcinomas as compared to benign colorectal tumors and controls. 140 51

Limiting factors in systemic recombinant interleukin-2 (rIL2) therapy may be overcome by intratumoral (IT) administration. A series of experiments was conducted to assess the efficacy of IT rIL2 alone and in combination with LAK cells and IFN-gamma. C57BL/6 mice bearing B16-F10 subcutaneous tumors were randomly assigned to treatment groups including: noninjected controls, IT placebo (NaCl, D5W), IT bovine serum albumin (BSA), IT rIL2 (centrally and peripherally), IT rIL2/LAK, IT rIL2/IFN-gamma, and intraperitoneal (IP) rIL2. A tumor size-dependent dose of cytokine was injected daily and LAK cells were given weekly. Systemic immune response was assessed by splenocyte mitogenesis and T-cell subset distribution using thymidine radioassay and flow cytometry, respectively. In terms of survival and tumor growth rate, IT rIL2 was superior to noninjected control, IT placebo, IT BSA, and IP rIL2 (P less than 0.05). The addition of IT LAK cells conferred no therapeutic advantage. The combination of rIL2 and gamma IFN-gamma had a slight survival benefit over rIL2 alone (30.8 days vs 20.4 days). Histologic analysis demonstrated an increase presence of intratumoral macrophages in the IT rIL2-treated tumors (P less than 0.05). Lymphocyte mitogenesis and L3T4+ subset were not altered by any treatment. In vitro thymidine uptake by tumor cells was not affected by rIL2 nor IFN-gamma alone but the combination of rIL2 and IFN-gamma resulted in significant tumor cell growth inhibition. Spontaneous lung metastases were more prevalent following central IT rIL2 (75% vs 29%, P = 0.07) not accountable by needle trauma but avoidable by the use of peritumoral injection.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Intratumoral rIL2-based immunotherapy in B16 melanoma. 140 10

Metastatic Lewis lung carcinoma (LLC) tumors stimulate myelopoiesis and, consequently, induce bone marrow cells to become immune suppressive to T cell blastogenesis and macrophage activation for tumor necrosis factor alpha (TNF-alpha) secretion. The suppressor cells phenotypically resembled granulocytic-monocytic progenitor cells. In order to diminish the presence of these immune suppressor cells, LLC-bearing mice were treated with low doses of gamma interferon (IFN-gamma) (100 units/mouse) plus TNF-alpha (10 units/mouse). Treatment of LLC-bearing mice with these low doses of IFN-gamma plus TNF-alpha diminished the suppressive activity of their bone marrow cells, as measured by the effect on normal macrophage activation to secrete TNF-alpha. In in vivo adoptive transfer studies, bone marrow from placebo-treated LLC-bearers stimulated tumor establishment and metastasis, while the bone marrow of IFN-gamma-plus TNF-alpha-treated tumor-bearers diminished LLC establishment and metastasis. The effect of the low dose treatments with IFN-gamma and/or TNF-alpha on the recurrence of excised s.c. tumors was also assessed. Treatment of mice following tumor excision with either IFN-gamma, TNF-alpha, or the combination of IFN-gamma plus TNF-alpha reduced recurrence. However, in the animals with recurring tumors only the combined IFN-gamma plus TNF-alpha treatment effectively diminished the development of lung metastases. These results demonstrate that low dose IFN-gamma plus TNF-alpha treatment diminishes the presence of suppressor and tumor growth-promoting activities of bone marrow and reduces tumor recurrence and metastasis.
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PMID:Myelopoiesis-associated immune suppressor cells in mice bearing metastatic Lewis lung carcinoma tumors: gamma interferon plus tumor necrosis factor alpha synergistically reduces immune suppressor and tumor growth-promoting activities of bone marrow cells and diminishes tumor recurrence and metastasis. 142 79

We investigated the ability of the TALL-103/2 and TALL-104 leukemic cell lines to produce lymphokines in response to activation signals, such as tumor cells and anti-CD3 (OKT3) or -CD2 (B67.1) monoclonal antibodies (mAb) or both. Both cell lines were found to produce high levels of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, and granulocyte-macrophage colony-stimulating factor (GM-CSF). The latter lymphokine is induced by lysable tumor cells and by immobilized OKT3 and B67.1 mAb only in the presence of interleukin (IL-2). IFN-gamma and TNF-alpha are induced upon CD3 but not CD2 stimulation, both in the presence and absence of IL-2. Interestingly, the B67.1 mAb amplifies the OKT3-induced responses by 2- to 10-fold, bringing the IFN-gamma and TNF-alpha levels of production up to 200 U/ml. Thus, simultaneous triggering of the CD2 and CD3 signaling pathways results in a very efficient lymphokine release. Of all the tumor cell lines tested as inducers, only K562 cells are able to stimulate the production of IFN-gamma and TNF-alpha in TALL-103/2 and TALL-104 cells, especially upon culture in IL-2. Lymphokine mRNA expression after stimulation with mAb or K562 cells peaks at 2 h in both cell lines. No messages are detectable in TALL-103/2 cells at 8 h, whereas in TALL-104 cells, IFN-gamma and GM-CSF transcripts are still present at 8 and 20 h, respectively. The inducible and highly regulatable expression of lymphokine release by these cell lines provides a unique model for studying mechanisms of lymphokine induction by different biological agents.
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PMID:Inducible expression of granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-alpha, and interferon-gamma in two human cytotoxic leukemic T-cell lines. 142 68

The receptor for tumor-promoting phorbol esters has been shown to be the Ca+2/phospholipid dependent enzyme protein kinase C (PKC). There are two major groups of PKC, the conventional PKC isotypes alpha, beta I, beta II, gamma) and the novel Ca+2-independent PKC (delta, epsilon, zeta, eta). Phorbol esters previously have been demonstrated to increase human IFN-gamma gene expression after treatment of a murine T cell line (Cl 9) that has been transfected with human IFN-gamma genomic DNA. In contrast, treatment with Ca+2 ionophore alone or in combination with phorbol ester did not enhance IFN-gamma production in a synergistic manner above the level obtained with phorbol ester treatment alone. To determine whether the lack of effect of Ca+2 ionophore is due to a defect in PKC, we compared the level of PKC autophosphorylation in the mouse T cell line (Cl 9), a mouse epidermal cell line (JB6), and purified rat brain PKC by in vitro kinase assays. The results demonstrate that instead of the expected 80-kDa autophosphorylated PKC band seen in purified rat brain PKC or mouse JB6 cell lysates, only a novel 97-kDa Ca+2-independent phosphoprotein was observed in Cl 9 cells. To ascertain if there was any nucleic acid sequence similarity to PKC epsilon, we hybridized Cl 9 poly(A+) RNA with a cloned fragment of the PKC epsilon gene and observed two hybridizing RNA bands (4.4 and 4.0 kb). Our results suggest that the 97-kDa phosphoprotein is similar to, but not identical with, PKC epsilon and is the major PKC expressed in the Cl 9 murine T cell line. These data suggested that the 97-kDa PKC may be responsible for the induction of both the transfected human IFN-gamma gene and the endogenous murine IL-2R alpha-chain.
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PMID:The presence in a mouse T cell line of a 97-kDa protein kinase C (PKC) with characteristics similar to known members of the novel PKC subgroup and its possible role in lymphocyte gene expression. 143 Nov 24

Cytokine-induced modulation of HLA expression on the cell surface of four human breast cancer cell lines was determined by continuous flow immunocytofluorometry with the aid of monoclonal antibodies directed to a non-polymorphic determinant of HLA class I and class II (DR) antigen. IFN-gamma and IFN-alpha were potent inducers of HLA class I in all examined cell lines, with decreasing inducibility as follows: BT-20, ZR-75-1, MCF-7 and MDA-MB-468 cells. HLA class II (DR) antigen was highly inducible by IFN-gamma in ZR-75-1 cells, followed by BT-20, MDA-MB-468 and MCF-7 cells. IFN-alpha increased the cell surface expression of DR antigen only in ZR-75-1 cells. IL-1-alpha induced a moderate level of HLA class I antigen in ZR-75-1, BT-20 and MDA-MB-468 cells, and HLA class II (DR) expression only in ZR-75-1 cells. This pattern of cell line inducibility by IL-1-alpha was similar to that induced by TNF-alpha. Differences in inducibility of HLA antigens on human breast cancer cell lines induced by different cytokines may reflect the differences in cytokine inducibility of the original tumor cells.
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PMID:Cytokine (IFN-alpha, IFN-gamma, IL-1-alpha, TNF-alpha)-induced modulation of HLA cell surface expression in human breast cancer cell lines. 143 41


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