Inhibition of human primary melanoma cell proliferation by histamine is enhanced by interleukin-6.

BACKGROUND: Interleukin-6 (IL-6) is a bifunctional growth factor in malignant melanoma; its expression increases during the malignant progression of the disease. Histamine, detected in large amounts in normal and pathological proliferating tissues, is an important paracrine and autocrine regulator of normal and tumour cell proliferation as well. MATERIALS AND METHODS: We investigated the presence and function of IL-6 and histamine in the WM35 primary human melanoma cell line with respect to their direct role in cell proliferation and their regulatory interactions. RESULTS: IL-6 inhibited the proliferation of WM35 melanoma cells and increased significantly the expression of histidine decarboxylase as well as histamine production. It had dose-dependent effects on the proliferation: high concentration (10-5 M) was inhibitory through H1 histamine receptors while low histamine concentration acting on H2 receptors, with a simultaneous increase of cAMP, enhanced colony formation in the monolayer. Furthermore, IL-6 increased the H1- but decreased the H2-histamine receptor expression of the melanoma cells. On the other hand, histamine was locally synthesized by the WM35 melanoma cells. CONCLUSION: We suggest that the growth arrest induced by IL-6 is in part mediated by its dual action on histamine: a shift toward H1 receptor predominance and an elevation of locally produced histamine with prevalent action on the inhibitory response triggered through the H1 receptor. These findings suggest a local cross-talk between histamine and IL-6 in the regulation of melanoma growth.

Suppression of melanoma cell proliferation by histidine decarboxylase specific antisense oligonucleotides.

Histidine decarboxylase (HDC) is expressed by the cells of melanoma, in which the histamine content tends to be relatively high. This study shows that elevated expression of HDC was found by western blot analysis of primary and metastatic melanoma tissue using a polyclonal HDC specific antibody. The specificity of anti-HDC antibody was confirmed by inhibition of HDC translation (i.e., immunopositivity) in melanoma cells by HDC-specific antisense oligonucleotide. Moreover, the decrease in proliferation caused by HDC antisense oligonucleotides indicates considerable functional relevance of histamine synthesis in melanoma growth and suggests a possible in situ application of specific antisense oligonucleotides for HDC in melanoma therapy.

Both interferon (IFN)alpha and IFNgamma inhibit histidine decarboxylase expression in the HT168 human melanoma cell line.

OBJECTIVE: Histamine plays an important role in a series of processes including inflammation, allergy, gastric acid secretion, neurotransmission, embryogenesis and in various tumours. Histidine decarboxylase (HDC), the enzyme solely responsible for generation of histamine is expressed in many cells including regenerating and tumour cells. HDC expression is regulated by multiple tissue factors, e.g. various cytokines and growth hormones. In this study the effect of interferon alpha and interferon gamma on the expression of HDC and on cell proliferation in vitro on melanoma cell line. METHODS: We used recombinant human interferon alpha, interferon gamma and human melanoma cell line HT168. RESULTS: Our data show that both IFNalpha and IFNgamma decreased the HDC mRNA and protein expression, though with dissimilar kinetics. IFNgamma strongly suppresses the proliferation at 72 h, while IFNalpha has a more moderate effect. CONCLUSIONS: Since previously the inhibitory effect of histamine on gene expression of interferon gamma was detected, a reciprocal inhibition between histamine and IFNgamma is proposed.

Histidine decarboxylase expression in human melanoma.

Histamine has been implicated as one of the mediators involved in regulation of proliferation in both normal and neoplastic tissues. Histidine decarboxylase, the only enzyme that catalyzes the formation of histamine from L-histidine, is an essential regulator of histamine levels. In this study, we investigated the gene and protein expression of histidine decarboxylase in melanoma. Reverse transcriptase polymerase chain reaction and in situ hybridization studies of WM-35, WM-983/B, HT-168, and M1 human melanoma cell lines both resulted in positive signals for histidine decarboxylase messenger RNA. A polyclonal chicken antibody was developed against human histidine decarboxylase and protein expression was confirmed by western blot analysis of the cell lysates, revealing a predominant immunoreactive band at approximately 54 kDa corresponding to monomeric histidine decarboxylase. Protein expression of histidine decarboxylase was also shown by flow cytometric analysis and strong punctate cytoplasmic staining of melanoma cell lines. Moreover, both primary and metastatic human melanoma tissues were brightly stained for histidine decarboxylase. When compared with the very weak or no reactions on cultivated human melanocytes both western blot and immunohistochemical studies showed much stronger histidine decarboxylase expression in melanoma cells. These findings suggest that expression of histidine decarboxylase is elevated in human melanoma.

Biosynthesis of interleukin-6, an autocrine growth factor for melanoma, is regulated by melanoma-derived histamine.

Interleukin-6 is an autocrine growth factor in advanced stage melanoma and biosynthesis of IL-6 is increased by histamine in various cell lines. In our study we analysed the direct relation of histamine and IL-6 synthesis in human melanoma cell lines. All melanoma cells contained IL-6 mRNA, but only metastatic melanoma cells secreted the IL-6 protein. The H1 histamine receptor antagonist triprolidine decreased gene expression and biosynthesis of IL-6, while other histamine receptor antagonists had no effect. These data indicate that endogenous histamine has a definite role in the regulation of local IL-6, suggesting that histamine and IL-6 could be part of autocrine growth regulation of the tumor.

H1 histamine receptor antagonist inhibits constitutive growth of Jurkat T cells and antigen-specific proliferation of ovalbumin-specific murine T cells.

Histamine is produced from histidine by histidine decarboxylase (HDC) in many cells including normal and malignant lymphocytes. We examined the expression of HDC and the effect of histamine receptor antagonists on the proliferation of a human T cell line, Jurkat and on antigen-driven proliferation of lymphocytes from ovalbumin-immunized mice. Our results demonstrate that HDC is inducible in Jurkat cells by anti-CD3. The H1 receptor antagonist triprolidine dose dependently inhibits proliferation of both Jurkat cells and ovalbumin-stimulated murine lymphocytes, while the H2 antagonist ranitidine was ineffective. Alpha-fluoro-methyl-histidine blocking HDC activity did not inhibit the T cell proliferation, suggesting an existing pool of histamine in T cells.

Histamine and histamine-receptor antagonists modify gene expression and biosynthesis of interferon gamma in peripheral human blood mononuclear cells and in CD19-depleted cell subsets.

The effect of histamine and histamine antagonists was examined on gene expression and biosynthesis of bacterial endotoxin (LPS) induced interferon gamma (IFNgamma) both in human peripheral mononuclear cells (PMBC) and in T-cell enriched fractions. We found, that histamine inhibited the LPS induced transcription of IFNgamma gene and biosynthesis of IFNgamma protein in PMBC and also in CD19-depleted cell populations. The inhibitory effect of histamine could be reversed by the H2 histamine receptor (HR2) antagonists cimetidine and ranitidine both in PMBC and in CD19-depleted cells, but not with triprolidine, an H1 receptor antagonist, suggesting that the inhibition of IFNgamma production is mediated through H2 receptors in these cell populations. In contrast to the inhibitory effect of histamine, cimetidine alone (in the absence of exogenous histamine) strongly stimulated both the IFNgamma mRNA and protein production, whereas this effect was hardly seen by and other H2 receptor blocker, ranitidine. This superinduction of IFNgamma gene by cimetidine disappeared if the CD19+ cells are removed from PMBC. These results suggest, that inhibition of IFNgamma gene expression by histamine is a direct effect of histamine on H2 receptor of T lymphocytes; however, the superinduction of IFNgamma by cimetidine requires the presence of other (probably primarily B) cell subsets.

Study of histamine effects on phagocytosis and enzyme secretion of Tetrahymena pyriformis.

1. The biogenic amine histamine develops effects not only in mammalian cells and tissues but in ciliated unicellular Tetrahymena as well. In addition to binding and internalization of labelled histamine, low concentrations can stimulate the phagocytosis of cells in inorganic salt solution. 2. In inorganic solution Tetrahymena cells secrete acid hydrolases to the medium. High concentration of histamine (10 mM) decreases the secretion of three investigated acid hydrolases in a different manner. We think that in this process the primary determinant is the alkaline character of histamine. 3. The effect of histamine on phagocytosis differs from the effect on secretion since the low, physiological concentration of histamine stimulates phagocytosis, the higher concentrations inhibit it. In the background of these effects possibly the hormone character is dominant. It is supported by the fact that histamine antagonists influence the process differently.

The relationship of the endoplasmic reticulum to the Golgi complex in Tetrahymena pyriformis.

The endoplasmic reticulum (ER) and the closely connected, single dictyosomal Golgi apparatus of Tetrahymena pyriformis cells showed random distribution in the cytoplasm. Ribosomes were evident, and coated vesicles pinched off from the ER were seen. The membranes of the endoplasmic reticulum generally formed a tube-like structure, although after histamine treatment multiple, folded and circular structures were observed. The number of coated vesicles detaching from the endoplasmic reticulum increased as a result of histamine treatment.

Secretory response of Tetrahymena to insulin: the influence of electric pulses.

The secretion of the enzyme hexosaminidase (HA) by Tetrahymena pyriformis, T. thermophila and T. thermophila mutant (MS1) cells was studied on the action of insulin or insulin in combination with electric pulses. The three species of Tetrahymena responded by different rates of enzyme activity. Following insulin or insulin + electrical pulses, the daughter cells of T. pyriformis manifested similar effects 24 h later by elevating the extracellular HA level, being higher when electrical pulses were included in the action on the parental cells. Insulin combined with electric pulses gave higher inter-strain differences in the reaction of Tetrahymena as reflected by HA enzyme measurements. MS1 cells lacking the capacity to release lysosomal enzymes when exposed to insulin with electric stimulation elicited a high level of HA released.

The effect of an electric field on the release of hexosaminidase in Tetrahymena.

The activity of beta-D-hexosaminidase was detected by spectrofluorometry in the growth media of three species of Tetrahymena. The enzyme activity was about six times higher in T. pyriformis compared with the wild cells of T. thermophila, while the MS-1 mutant of T. thermophila manifested very low enzyme activity under the same experimental conditions. An electric field and electrical pulses produced significant though different increases in enzyme activity in media of wild and mutant T. thermophila. In contrast, T. pyriformis responded to the field pulses by decreasing the activity of the enzymes detected in the growth media.