Lysis of allogeneic and autologous melanoma cells by IL-7-induced lymphokine-activated killer cells

In order to assess the potential of interleukin 7 (IL-7) as an immunotherapeutic agent in human melanoma, we have evaluated the in vitro activity of IL-7-induced lymphokine-activated killer (LAK) cells from patients with advanced melanoma against allogeneic and autologous melanoma cells. Peripheral blood lymphocytes (PBLs) from 14 patients with stage III melanoma were isolated and incubated in the presence of 1,000 U ml-1 IL-7 and 100 U ml-1 IL-2 for comparison. LAK-cell activity was determined by a 24 h cytotoxicity assay using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide]. The activity of IL-7-induced LAK cells against two allogeneic melanoma cell lines was 32.7% (+/- 17.9) against SK-Mel-37 and 38.1% (+/- 12.5) against SK-Mel-23 at an effector-to-target (E/T) ratio of 20:1. The activity of IL-2-induced LAK cells was significantly higher against SK-Mel-37 (78 +/- 24.6%) and against SK-Mel-23 (73.5 +/- 19.7%). IL-7 and suboptimal doses of IL-2 (10 U ml-1) were found to have a co-stimulatory on lymphocyte proliferation as well as on LAK activity. Against autologous melanoma cells, the activity of IL-7- and IL-2-induced LAK cells did not differ significantly (55.8 +/- 25.6% versus 68.7 +/- 21.7% respectively). In two patients, IL-7-induced LAK-cell activity against autologous melanoma cells exceeded even that of IL-2 significantly (67% vs 35% and 95% vs 82%). Levels of tumour necrosis factor alpha (TNF-alpha) in the supernatants of LAK-cell cultures generated by IL-7 were lower than those of IL-2-generated LAK-cell cultures. These results suggest that IL-7 is a potential alternative to immunotherapy with IL-2 in terms of efficacy and possible side-effects and encourages pilot studies with IL-7 in melanoma patients.

Distribution of constitutive nitric oxide synthase immunoreactivity and NADPH-diaphorase activity in murine telogen and anagen skin

The freely diffusible radical nitric oxide is generated by nitric oxide synthase, and is a pleiotropic, bioregulatory molecule that regulates, e.g., the vascular tone, functions as a major neurotransmitter, and is involved in macrophage-mediated cytotoxicity and platelet aggregation. Constitutive nitric oxide synthase exhibits NADPH-diaphorase activity that can be demonstrated histochemically. To study whether this enzyme is present in mammalian skin during distinct phases of the murine hair cycle, we have examined cryosections of C 57 BL-6 mouse skin in telogen and depilation-induced anagen VI. Histochemical analysis of NADPH-diaphorase activity was complemented by immunohistology, using two specific rabbit antisera against constitutive neuronal nitric oxide synthase. Epidermis and the outer root sheath showed both immunoreactivity for the enzyme and NADPH-diaphorase activity, whereas dermal papilla and sebaceous glands displayed only strong NADPH-diaphorase activity, suggesting that this enzyme histochemical test measures additional enzymes besides nitric oxide synthase. Intrinsic nitric oxide synthase immunoreactivity was also detected by immunoblot in mouse skin homogenates, staining proteins of an apparent 160-kDa molecular weight. Compared to telogen skin, these immunoreactive proteins were quantitatively increased in anagen VI skin. Thus, our study suggests that defined epithelial compartments of normal murine skin are capable of synthesizing nitric oxide and that the molecule may be involved in skin physiology, growth, and remodeling.

Hair growth induction by substance P

BACKGROUND

In vitro, some neuropeptides, including the tachykinin, substance P (SP), act as growth factors. The cyclic growth of the richly innervated hair follicle offers a model for probing such functions in a complex, developmentally regulated tissue interaction system under physiologic conditions. Dissecting the role of neuropeptides in this system may also reveal as yet obscure neural mechanisms of hair growth control.

EXPERIMENTAL DESIGN

The neuropeptide-releasing neurotoxin, capsaicin was injected intradermally, or SP slow-release formulations were implanted subcutaneously in the back skin of C57BL/6 mice with all follicles in the resting stage of the hair cycle (telogen) in order to see whether this induced hair growth (anagen). In addition, the endogenous SP skin concentration and the activity of the main SP-degrading enzyme, neutral endopeptidase, were determined during the induced murine hair cycle by high performance liquid chromatography-controlled radioimmuno-assay (SP) or by fluorometry (neutral endopeptidase).

RESULTS

Both capsaicin and SP induced significant hair growth (anagen) in the back skin of telogen mice. This was associated with substantial mast cell degranulation. The endogenous SP skin concentration showed significant, hair cycle-dependent fluctuations during the induced murine hair cycle, which were largely independent of the activity of neutral endopeptidase.

CONCLUSIONS

SP may play a role in the neural control of hair growth. Whereas this pilot study does not address the underlying mechanisms of action, it demonstrates that SP has potential as a hair growth-stimulatory agent in vivo, and serves as a basis for exploring the role of tachykinins in epithelial-mesenchymal-neuroectodermal interaction systems like the hair follicle.

[Vitamin D3 and its analogs as multifunctional steroid hormones. Molecular and clinical aspects from the dermatologic viewpoint]

Since the identification of the cholesterol derivative 1,25-dihydroxy-vitamin D3 and its analogues as potent immunomodulatory, proliferation- and differentiation-regulatory molecules, the amount of data available on the effects of these agents on the skin and its appendages has grown exponentially. This review outlines recent progress in the understanding of the molecular biology and pathophysiology of vitamin D, and new strategies for the treatment of skin diseases are discussed. Focusing on psoriasis and preliminary clinical experiences, we discuss possible therapeutic targets and perspectives for these multifunctional steroid hormones in dermatology.

Interleukin-7 induces differential lymphokine-activated killer cell activity against human melanoma cells, keratinocytes, and endothelial cells

To assess the potential role of interleukin (IL)-7 in immunotherapy of human malignant melanoma, we have examined the lymphokine-activated killer (LAK) cell sensitivity of four human melanoma cell lines against LAK cells generated by IL-7 or IL-2. Lysis was determined by a 24-h cytotoxicity test using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT). All melanoma cell lines were susceptible to IL-7- and IL-2-generated LAK cells. The sensitivity of melanoma cells to IL-2-induced LAK cells was higher compared to IL-7-induced LAK cells. At an effector target ratio of 20:1, the lysis by IL-7-induced LAK cells ranged between 41% and 52%, whereas IL-2-induced lysis ranged between 80% and 94% (p < 0.01). IL-7-induced LAK cells, however, showed almost no cytotoxicity towards HaCat keratinocytes and human umbilical vein endothelial cells (HUVECs). Immunophenotyping revealed a higher expression of the tac antigen (CD 25) on IL-7-generated LAK cells, particularly those cells that were CD 56 negative or CD 3 positive compared to IL-2-induced LAK cells. In contrast, IL-2-generated LAK cells killed 62% of the HaCat keratinocytes and 60% of the HUVECs. Secretion of tumor necrosis factor-alpha into culture supernatants was significantly higher in IL-2-generated LAK cells compared to IL-7-stimulated LAK cells (p < 0.01), whereas TNF-alpha levels of IL-7-induced LAK cells were in the range of unstimulated lymphocytes. Because nonspecific cytotoxicity against other normal cells such as keratinocytes and endothelial cells contributes to the dose-limiting side effects of immunotherapy with IL-2, immunotherapy using IL-7 might be a better tolerated future alternative.

Correlation of proteolytic activities of organ cultured intact mouse skin with defined hair cycle stages

The cyclic growth activity of the hair follicle is characterized by substantial remodelling of the extracellular matrix, yet, little is known about the proteolytic activities regulating this process. In murine skin, hair cycling is highly synchronized and is associated with dramatic remodeling of all skin compartments. We therefore have assessed, in this pilot study, proteolytic activities of murine skin from various stages of the depilation-induced hair cycle. We show that the defined proteolytic activities displayed by organ cultured intact mouse skin differ between hair cycle stages. Skin with all follicles in telogen or mid anagen displayed only minimal lysis of collagen type I gels, while early anagen skin had significant collagenase activity. Skin cultured on gelatin gels at the air-liquid interphase ('histoculture') completely lysed the gel within 5 days when all follicles were in early anagen, while this was not observed with mid and very late-anagen skin. Zymography of conditioned medium from these cultures revealed the secretion of activated interstitial collagenase and of gelatinases of 72 and 92 kDa, with the maximum of interstitial collagenase activity secreted by anagen IV skin. Addition of TPA or TNF-alpha to the culture medium stimulated secreted collagenase type I activity. The C 57 BL-6 mouse offers an attractive model for dissecting and manipulating hair cycle-associated proteolysis in a physiologically relevant system.

Foreign-body granuloma and IgE-pseudolymphoma after multiple bee stings

We report a patient with an unusual combination of an eosinophilic foreign-body granuloma and a pseudolymphoma, with recurrent severe oedema on the forehead, after multiple bee stings. On immunohistology the foreign-body granuloma and lymphoid follicles reacted with monoclonal antibodies against the high- and low-affinity IgE receptors, and against IgE. Prick and intradermal tests with whole-body bee extracts showed positive immediate-type reactions. The eosinophilic granuloma formation and lymphoid follicles may have been induced by a combination of immune complex and cell-mediated hypersensitivity following antigen persistence. Although bee stings are common, as far as we are aware, this complex reaction pattern has not been reported previously.

Mast cell involvement in murine hair growth

We have examined the possibility that an involvement in hair growth regulation is one of the still obscure physiological roles of mast cells (MC) in normal skin. Using the murine hair cycle as a model, we first studied the number, localization and granulation status of skin MC during the hair cycle of C57 BL-6 mice. Shortly after the induction of hair growth (anagen) in the back skin of mice with resting (telogen) follicles, a sharp decline in the number of Giemsa-stainable MC was detected by morphometry. This was evident in depilation-induced, pharmacologically induced, and spontaneous anagen. By light and electron microscopy, the anagen-associated decline was correlated with the occurrence of substantial MC degranulation. In vivo, the IgE-independent MC secretagogues, compound 48/80 and ACTH, induced anagen in mouse telogen follicles after intracutaneous administration, while inhibitors of mast cell degranulation (cromoglycate, tiacrilast) and antagonists of selected MC products (clemastin, ranitidine, ketanserin) significantly retarded the induced development of anagen follicles in these mice. It is suggested that MC act via their secretory products as stimulators of anagen development in mice and that the murine hair cycle is an excellent model for studying growth regulatory functions of MC in developmentally regulated systems.

[Pilot study of the effect of interferon-alpha on atopic eczema]

In this pilot study 12 patients with moderate to severe atopic eczema were treated with 2 million IU interferon alpha 2a (Roferon A) three times weekly for 8 weeks and followed up for a further 10 weeks: 2 patients showed clear and 9 a slight to moderate reduction of their skin lesions; 1 patient got worse. Pruritus did not decrease and even increased in a few patients, and IgE levels showed no change during and after treatment. All patients noted mild, transient, flu-like symptoms. The efficacy of interferon alpha in the present therapeutic design for the treatment of atopic eczema must thus be classified as only moderate.

Chemotherapy-induced alopecia in mice. Induction by cyclophosphamide, inhibition by cyclosporine A, and modulation by dexamethasone

We introduce cyclophosphamide-induced alopecia (CYP-IA) in C57BL-6 mice as a clinically relevant model for studying the biology of chemotherapy-induced alopecia and for developing anti-alopecia drugs. One injection of CYP to mice with all back skin follicles in anagen VI induces severe alopecia that strikingly reproduces the follicle response, recovery, and histopathology seen in human CYP-IA. CYP dose-dependently induces abnormal follicular melanogenesis and dystrophic anagen or, in more severely damaged follicles, dystrophic catagen. Both dystrophy forms are followed by an extremely shortened telogen phase, but differ in the associated hair loss and in recovery patterns, which determines hair regrowth. This follicular response to CYP can be manipulated pharmacologically: systemic cyclosporine A shifts it toward a mild form of dystrophic anagen, thus retarding CYP-IA and prolonging "primary recovery". Topical dexamethasone, in contrast, forces follicles into dystrophic catagen, which augments CYP-IA, but accelerates the regrowth of normally pigmented hair ("secondary recovery").

Inhibitory effects of sulfonated shale oils (ammonium bituminosulphonates, Ichthyols) on enzymes of polyenoic fatty acid metabolism

The two commercial pharmaceutical preparations of ammonium bituminosulphonates, Leukichthol and Dark Ichthyol, were shown to inhibit the formation of 5S-hydroxy-6E,8Z,11Z,14Z-eicosatetraenoic acid (5-HETE) from external arachidonic acid by human polymorphonuclear leukocytes stimulated by ionophore A-23187 in a dose-dependent manner. Pure arachidonate 15-lipoxygenases from rabbit reticulocytes and soya beans, and the particulate prostaglandin endoperoxide synthase from sheep vesicular glands, were also inhibited. With the reticulocyte lipoxygenase, the Ichthyols suppressed the enzyme activity by two different mechanisms: (1) a prolongation of the lag period typical of lipoxygenase catalysis, and (2) by a lowering of the maximal enzymatic activity after the end of lag period. As expected, the first effect was reversed by the addition of the lipoxygenase product 13S-hydroperoxy-9Z,11E-octadecadienoic acid (13-HpODE). Ammonium bituminosulphonates are thus universal inhibitors of lipoxygenase activities, and the latter are of potential importance in inflammatory dermatoses.

Distribution and changing density of gamma-delta T cells in murine skin during the induced hair cycle

Gamma-delta T cells (gdTC) are recognized as the predominant intraepidermal T-cell population in murine skin, although their physiological functions are still unclear. Little is known of the exact distribution of gdTC in the other epithelial skin compartments of normal mice. Using selective gdTC-receptor antibodies in immunohistology (alkaline phosphatase technique), the distribution and density of gdTC was analysed morphometrically in cryostat sections of full-thickness back skin of normal, adolescent C57 BL-6 mice in all the different stages of the depilation-induced hair cycle. We found that, during the entire hair cycle, V gamma 3-TCR-bearing lymphocytes are restricted to the epidermis, and to the epithelial hair bulb in, and distal to, the bulge area. No gdTC were seen in the sebaceous glands. During early anagen development, the number of pan-gdTC receptor-positive cells increased significantly (P < 0.005) in the interfollicular epidermis and the suprainfundibular portion of the hair bulb, whereas the number decreased in the infrainfundibular region (P < 0.005). As gdTC are thought to migrate into the skin only during embryogenesis, this finding suggests hair cycle-dependent, differential intraepithelial proliferation of gdTC in murine skin. We advocate employing only skin of defined hair cycle stages in immunological studies on murine skin, and discuss the value of the C57 BL-6 model for assessing the functions of gdTC in skin and hair biology.

Nerve growth factor modulates keratinocyte proliferation in murine skin organ culture

Despite the fact that several cell types residing in or travelling through the skin are targets and/or sources of nerve growth factor (NGF), little is known about the role of NGF in skin development, physiology and disease. Employing a previously defined skin organ culture assay for studying the proliferation of murine keratinocytes in their natural tissue environment, we have assessed the effect of murine NGF (7S) on keratinocyte proliferation in intact skin derived from two defined stages of the murine hair cycle. We found that 10-200 ng/ml NGF stimulated epidermal keratinocyte proliferation in organ-cultured C57 BL-6 mouse skin in the telogen phase of the hair cycle. Follicle keratinocyte proliferation was stimulated by 100 ng/ml NGF in telogen skin organ culture, but this concentration of NGF inhibited both epidermal and follicle keratinocyte proliferation in organ culture of anagen skin. The latter inhibitory effect of NGF was abrogated by co-incubation with neutralizing anti-NGF antibodies or with the protein kinase C inhibitor staurosporine. The proliferation-modulatory effects of NGF were associated with the induction of significant mast cell degranulation, and were inhibited by cromoglycate co-administration. This is the first report of a modulatory, hair cycle-dependent effect of NGF on keratinocyte proliferation in situ, which may require the presence of mast cells. Our study supports the notion of auto- and paracrine functions of NGF in murine skin physiology, which can be further assessed in the physiologically relevant mouse model delineated here.

Chemosensitivity testing of human malignant melanoma. A retrospective analysis of clinical response and in vitro drug sensitivity

BACKGROUND

Clinical response rates in the treatment of patients with disseminated malignant melanoma are low and unpredictable. Several reports have documented that clonogenic assay systems for in vitro drug testing are capable of predicting resistance to therapy in vivo and might provide guidelines to improve clinical response rates.

METHODS

Specimens from metastatic lesions of patients with malignant melanoma, predominantly from lymph nodes and skin, were disaggregated, exposed to a panel of 10 cytotoxic drugs for 1 hour, and subsequently cultured in agarose. Effects were calculated by the ability to form tumor colonies compared with an untreated control after 7-14 days. A retrospective comparison between the in vitro drug testing result and clinical response was possible in 19 cases.

RESULTS

An average of 7.3 drugs per specimen were tested. A high degree of resistance was observed against all cytostatic agents studied independently of the tumor site. In 47 of 181 in vitro drug tests, tumor colony formation was reduced by 30-50%; in 17 of 181, the reduction was more than 50%. A retrospective analysis showed no clinical response in 11 cases and one mixed response in which patients received drugs that had been shown to be "resistant" in vitro.

CONCLUSIONS

These results support the concept that in vitro drug testing promises to help avoid treatment with ineffective drugs and their associated toxic side effects. Furthermore, it may increase the likelihood of obtaining a clinical response in the treatment of disseminated malignant melanoma. The major limitation in the treatment of malignant melanoma is the lack of availability of effective agents for treatment.

Amelanotic malignant melanoma presenting as malignant schwannoma

A 78-year-old woman presented with a 14-month history of a nodule on the sole of her left foot. It had been increasing in size, and had become ulcerated. Histological, immunochemical and ultrastructural studies of the primary tumour revealed melanocytic and Schwannian characteristics, and posed diagnostic difficulties. The final diagnosis of a malignant melanoma with Schwannian differentiation was established on the basis of the clinical course, with the development of metastases in the subcutis, lymph nodes, liver and brain, as well as a shift in differentiation of the metastases towards cells containing giant melanosomes, typical of melanoma.

Expression of growth factor receptors on human melanoma cells: comparison of modulating effects of interferons and retinoids

Autocrine and paracrine growth factors are important mediators in malignant transformation. Interferons (IFN) and retinoids (RX) are well-known differentiative and immunomodulating agents with effects on subsets of different human tumors including malignant melanoma. In this study, we examined the modulating effects of three IFN and seven different RX on human melanoma cell lines regarding growth factor receptor expression. Growth factor receptor expression, including PDGF-R, NGF-R, EGF-R, IR, IGF-I-R, TFR and c-kit, was studied by immunohistochemistry and FACSscan analysis. Both groups of substances modulated the expression of some growth factor receptors. Upregulation of PDGF-R was seen after treatment with IFN as well as with RX. In contrast, EGF-R was found to be downregulated in two EGF-R-positive cell lines by IFN and, on the other hand, induced by RX in two EGF-R-negative cell lines. The expression of NGF-R was modulated ambiguously by these substances but demonstrated a cell line specificity in the different melanoma cell lines tested. Additionally, some of the tested growth factor receptors were not markedly changed regarding their expression by treatment with IFN and RX (IR, IGF-I-R, c-kit, TFR).

Inositol phosphate formation and release of intracellular free calcium by bradykinin in HaCaT keratinocytes

Phospholipase C-mediated release of inositol trisphosphate, followed by an increase in free intracellular calcium, is an important signal transduction pathway for several membrane receptors. In the present investigation, the coupling of various receptors to phospholipase C was studied in the human keratinocyte line HaCaT. Inositol trisphosphate formation was determined by anion-exchange chromatography, and the release of intracellular calcium was analysed with the fluorescence probe Fura-2 AM. Activation of HaCaT keratinocytes with bradykinin resulted in a time- and dose-dependent release of inositol trisphosphate and intracellular calcium, with an EC50 value of 50 nM for bradykinin-induced inositol trisphosphate formation. The mediators and cytokines IL-1, IL-4, IL-6, IL-8, EGF and TGF alpha, as well as bombesin, prolactin, carbachol, substance P and retinoic acid, did not activate this pathway. The inability of the mediators examined to activate phospholipase C may be due to lack of the respective cognate receptors or to the use of other signal transduction pathways.

[Recurrent nodular panniculitis in alpha 1-antitrypsin deficiency. Successful dapsone therapy]

We present a 59-year-old woman with chronically relapsing and necrotizing nodular panniculitis and associated alpha 1-antitrypsin deficiency. All cutaneous symptoms cleared for the first time in 10 years once she started treatment with dapsone. Chronic panniculitis should lead the clinician to determine plasma alpha 1-antitrypsin levels in more cases.

Human mast cells produce IL-8

Recruitment of neutrophils is a common feature in diseases that are associated with mast cell activation. The mechanisms that mediate neutrophil activation are not well understood. IL-8 is a recently described potent chemotactic factor that might be pathogenetically involved in this process. We therefore studied the human mast cell line HMCI and human skin mast cells for their ability to produce IL-8 using various stimuli. IL-8-mRNA was expressed in a stimulus- and time-dependent fashion as detected by Northern blot analysis with an IL-8-specific cDNA probe. The molecular mass of HMCI-derived IL-8 was determined to be about 8 kDa by immunoblot analysis. Immunoreactive and biologically active IL-8 protein was measured in the cell culture supernatants of HMCI cells by an ELISA and a chemotaxis assay, respectively. On immunoelectron microscopy of stimulated skin mast cells, IL-8 was found along cytoplasmatic membranes and in intracellular granules. Our data indicate that mast cells may contribute to neutrophil recruitment by secretion of IL-8.