摘要:

Lectin binding is known to be able to elicit signalling events relevant for various aspects of cell physiology. The influence of lectin binding on melanoma cells remains relatively unexplored. The aim of our study was to investigate the in vitro effects of five plant lectins, namely peanut (PNA), wheat germ (WGA), concanavalin A (Con-A), Griffonia simplicifolia (GSA-IA4) and Phaseolus vulgaris (PHA-L) agglutinins, on the cell proliferation of melanoma cell lines (SK-MEL-28, HT-144 and C32) cultured in media supplemented with either 10% or 1% fetal calf serum (FCS). Cell proliferation was assessed by means of the tetrazolium derivative reduction (MTT) assay. Four lectin concentrations were tested, namely 0.05, 0.5, 5 and 50 ug/ml, in four experimental settings, namely 1, 3, 5 and 7 days after the addition of each lectin to the culture media. Determination of the cell gain compartment (percentage of cells in the S and G2 phases of the cell cycle) was done by means of digital cell image analysis assessed on Feulgen-stained nuclei. Our results demonstrated that of the five lectins under study, four had a globally significant dose-dependent toxic effect on melanoma cell proliferation. The fifth lectin, PNA, had a significant stimulatory effect on the C32 cell line. Low doses of lectins may produce a transient increase in cell proliferation. Increasing the FCS from 1% to 10% in the culture media significantly antagonized lectin-induced toxicity in the three cell lines. The cell kinetics measurements showed that the inhibition of cell growth was merely due to cell death. The present data strongly suggest that some lectins might influence the proliferation of melanoma cells. In addition, because lectins are present in our diet and are able to pass into the systemic circulation, we speculate that lectins may exert an influence on melanoma growth under clinical conditions.

ISSN:0960-8931    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The cytotoxicity of the (-)- and (+)-isomers and the quinone metabolite gossypolone prepared from the naturally occurring polyphenolic dialdehyde gossypol were compared using two human melanoma cell lines (SK-mel- 19 and SK-mel-28) with a similar growth rate, one melanotic (melanin content of 69 pg/cell) and one amelanotic (melanin content of 10 pg/cell). Results from two viability assays (MTT and flow cytometry) showed that the cytotoxicity of racemic gossypol was identical for both cell lines (50% inhibition of cell growth IC50=22 µ). Gossypolone at equimolar concentrations was inactive in the amelanotic cell line and as potent as racemic gossypol in the melanotic cell line. (-)-Gossypol was significantly more active in both cell lines compared with the (+)-isomer. The cytotoxic effect of (-)-gossypol was both concentration and time dependent. Under serum-free conditions, the cytotoxicity of both enantiomers was increased, suggesting that serum protein binding may play a role in the differential toxicity of these isomers in vitro. Morphological changes after exposure to (-)-gossypol included shrinkage and loss of adherence. Cell sensitivity to the (-)-isomer was five-fold greater (IC50=4 µM using a clonogenic assay. At equimolar concentrations, (-)-gossypol was more cytotoxic to both cell lines than the clinically used drugs cisplatin, dacarbazine and melphalan. The results of this study suggest that (-)-gossypol may be of potential therapeutic benefit in melanoma patients.

ISSN:0960-8931    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

We studied the response of mouse B16F10 and SK-MEL-28 and SK-MEL-1 human melanoma cell lines to treatment with 4-hydroxyanisole (4-HA), and attempted to relate the response to the dopa oxidase levels and the morphological characteristics of each cell line. Clear dose-response curves were observed after 24 h of treatment in each cell line, the 4-HA being more toxic to the B16F10 cells, with an ID50 value of 215 nM. This was much lower than that observed for the SK-MEL-28 and SK-MEL-1 cell lines (ID50 of 5.98 mM and 7.17 mM, respectively). There was a direct relationship between toxicity levels and dopa oxidase activity, since the highest specific activity was obtained for B16F10 (15.9 mil), while lower activity was registered for SK-MEL-28 (4.59 mU) and SK-MEL-1 (1.24mU), which also showed lower 4-HA toxicity. Morphologically, we observed the typical characteristics of cellular injury, with swelling and dilation of the internal membranes and organelles, an increased number of vacuoles, and an increased number of abnormal multilamellar melanosomes or thick clumps of irregularly distributed melanin. On the other hand, we observed that the two cell lines with the lowest dopa oxidase activity contained more mature fully melanized melanosomes than B16F10, pointing to possible alterations in the melanosome transference mechanism and lower enzymatic activity in the mature melanosomes of these two human cell lines.

ISSN:0960-8931    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The influence of gonadal steroids on human melanoma still remains a controversial issue. The aim of our study was to investigate whether sex steroids may influence the biological characteristics of human melanoma. Such biological characteristics were monitored at the morphological level by means of computer-assisted microscope analysis of Feulgen-stained nuclei, which provides 28 quantitative variables describing the nucleus morphometry (size, anisonucleosis level) and chromatin pattern. This methodology was used to characterize the morphonuclear features in a series of 69 human melanomas (from formalin-fixed paraffin embedded tissues) including 28 male, 17 premenopausal and 24 postmenopausal female patients, and to investigate the effect of two sex steroids (5-a-dihydrotestosterone [DHT] and 17-p-oestradiol [E2]) on three human melanoma in vitro models - the HT-144, SK-MEL-28 and C32 cell lines. The results show that the morphonuclear characteristics of melanoma originating from male and female patients are very distinct (P< 0.01). This difference is still more marked (P < 0.0005) when only premenopausal female patients are compared with male patients. The in vitro data show that both DHT and E2 are able to modify markedly (P < 0.001 to P < 0.0001) the nucleus morphometry and chromatin pattern of the three cell lines. Although the mechanism and the physiological outcome are still unknown, the present work shows that there is in vivo and in vitro evidence that the biological behaviour of human melanoma is influenced by sex steroids.

ISSN:0960-8931    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Elevated levels of the phaeomelanin metabolite 5-S-cysteinyldopa and the eumelanin metabolite 6-hydroxy-5- methoxyindole-2-carboxylic acid in urine and serum have been shown in previous studies to correlate with disseminated malignant melanoma. Immunohistochemical detection of S100B protein is an acknowledged method for the diagnosis of malignant melanoma, and it has been suggested that rising serum levels of S100B protein are associated with the survival rate of patients with malignant melanoma. In the present study serum levels of S100B protein and urinary concentrations of 5-S-cysteinyldopa and 6-hydroxy-5-methoxyindole-2-carboxylic acid were measured in 91 patients with histopathologically verified malignant melanoma. At the time of sampling 13 patients were in clinical stage I, 13 in stage II and 65 in stage III. The urinary levels of the melanin metabolites were determined by automated high performance liquid chromatography, and the serum levels of S100B protein by an immunoradiometric assay with two monoclonal antibodies. The overall survival rate was most strongly associated with the serum levels of S100B protein (P< 0.001), but there was also a significant correlation to urinary levels of 5-S-cysteinyldopa (P< 0.001). A corresponding association with urinary levels of 6-hydroxy-5-methoxyindole-2-carboxylic acid was found in only a very few patients with extremely high urinary concentrations. A statistically significant increase in relative hazard was found for S100B protein levels exceeding 0.6 ng/l (P< 0.001), and predictably for patients in clinical stage III (P< 0.001). An analysis of S100B protein levels in patients in clinical stage III showed a significant correlation to survival (P=0.005). Our study suggests that of the three biochemical tumour markers, S100B and to a lesser extent 5-S-cysteinyldopa have the greatest potential to be used as predictors of survival prognosis in patients with malignant melanoma.

ISSN:0960-8931    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Tumour hypoxia can lead to a decrease in the biological effectiveness of radiation and alkylating agents. Few data are available on oxygen tension (Po2) in melanoma. In 20 patients with past history of melanoma, Po2was evaluated in normal tissues and suspected metastatic lesions (nodes and skin metastases). Oxygen tension was measured using a needle probe technique (KIMOC-6650 histograph, Eppendorf, Germany), the day before the surgical removal of the suspected metastatic lesion. Histological confirmation of the malignant origin of the removed lesion was obtained in 18 cases. In two cases invasion by the known melanoma was not seen histologically. The median Po2for normal tissues was 40.5 mmHg. For tumours, the median Po2was 11.6 mmHg, and it was 17.1 mmHg in nodes and 6.7 mmHg in skin metastases. Very low values (< 2 mmHg) accounted for 20% of the recorded values in nodes and 15% in skin metastases. when analysed according to the node size ( 7<or & 3 cm in diameter), the median Po2was 10.4 mmHg in large nodes (six patients) and 53.3 mmHg in small nodes (six patients). For the two non-tumoral lesions, the median Po2values were 20.9 and 25.1 mmHg, with no values below 10 mmHg. Thus a decrease in Po2values, probably corresponding to tumour hypoxia, was found in most of the metastatic tumours when compared with normal tissues. The prognostic value of these Po2measurements in melanoma remains to be demonstrated in the tumour response to radiotherapy or alkylating agents. However, tumour hypoxia can already be investigated as a target for new treatment modalities in metastatic melanoma.

ISSN:0960-8931    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The atypical naevus is both a risk factor for and a precursor lesion of melanoma. Sunlight is known to be an important aetiological factor for melanoma. Whether solar exposure is also involved in the initiation of (atypical) naevi is an issue of current interest. We performed a cross-sectional study among 270 inhabitants in the cloudy Netherlands and 282 white Dutch immigrants of the tropical island Curacao to investigate whether solar exposure plays a role in the development of atypical naevi. All participants were interviewed and underwent total skin examination; banal melanocytic naevi and atypical naevi were counted. There was no significant difference in the mean number of melanocytic naevi ≥ 2 mm or ≥5 mm between Curacao and the Netherlands. Furthermore, there was no significant difference in the mean crude and age standardized prevalence of atypical naevi between the Netherlands and Curacao. In both groups individuals with atypical naevi had significantly more total naevi. Concerning the role of sun exposure in the development of naevi in the Netherlands, we found that the total naevus count had a significant association with cumulative sun exposure before the age of 12 as well as with two or more painful sunburns before the age of 12. In Curacao these relationships were not observed. In contrast, however, on Curacao the presence of atypical naevi showed an association (odds ratio=2.6, 95% confidence interval 1.1-6.0) with the highest level of cumulative sun exposure and with painful sunburns before the age of 12 (odds ratio=2.6, 95% confidence interval 1.2-5.5). In the Dutch group these associations were not significant. We hypothesize that in the development of banal naevi there is an association between the total number of naevi and sun exposure only at low exposure levels; however, after overstepping a critical threshold a further association between melanocytic naevi and sun exposure is lacking. Sunlight exposure before the age of 12 plays a complex role: only very high exposure levels seem to contribute to the development of atypical naevi.

ISSN:0960-8931    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Isolated limb perfusion (ILP) has been reported as the most effective treatment for localized recurrent melanoma of the limbs. In terms of local and regional control with melphalan, complete remission is achieved in about 40% of patients, with frequent toxicity causing significant short-term disability in many and long-term incapacity in a few. Since 1989, several studies have reported success using a combination of fotemustine and dacarbazine (DTIC) in the systemic treatment of disseminated melanoma and brain metastasis. In May 1995, we began a pilot study with systemic DTIC 400 mg/m2 given intravenously about 4 h before ILP using fotemustine in an intra-arterial bolus of 100-150 mg/m2 as the perfusion agent. By July 1996, 10 patients had been included in the study. The results were evaluated in terms of the response rate (five complete responses and one partial response in the six patients who could be evaluated), local toxicity (nine patients with level I and one with level II, measured on the Wieberdink scale) and systemic toxicity (nine patients with level 0 and one with level 1, measured on the World Health Organization scale). Treatment was effective, with a similar response rate to that obtained with melphalan but with much lower toxicity, so this protocol may represent an innovation in loco-regional therapy and should be further investigated in a large trial.

ISSN:0960-8931    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

In order to estimate the therapeutic activity and tolerability of immunochemotherapy with recombinant interferona2b (HFN-a2b) plus dacarbazine (DTIC), a study was carried out in 61 patients with cytologically and/or histologically confirmed metastatic malignant melanoma. The treatment regimen was as follows: rlFN-a2b 2X1O6IU intramuscularly on days 1 to 4, and DTIC 800 mg/m2 intravenously on day 5, repeated at 3-week intervals until the progression of the disease or, in the case of a complete response, for up to 6 months. The overall response rate was 28%-12% complete response (CR) and 16% partial response (PR). The median response duration was 10.9 months (CR 11.5 months, PR 9.3 months; P>0.05). Responses occurred in soft tissue and lung metastases only. The median times to treatment failure for responding and non-responding patients were 10.9 and 3 months, respectively (P> 0.0001), and the median survival durations were 16.5 and 5.8 months, respectively (P> 0.0001). The stratification of the patients into a low-risk group (World Health Organization performance status [WHO PS] ≤1 and soft tissue or lung metastases) and a high-risk group (WHO PS=2 or disease localization other than skin, lymph nodes or lung) showed a significant advantage for the first group with respect to the response rate, median time to treatment failure and survival duration. A flu-like syndrome was recorded in 72% of patients, nausea and vomiting in 34%, haematological toxicity in 26%, hepatic toxicity in 5%, and neurotoxicity in 5%. In view of the results obtained in our study and those reported in the literature, IFN plus DTIC immunochemotherapy represents a reasonable treatment option, particularly for patients with soft tissue and lung metastases

ISSN:0960-8931    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The objective of this study was to determine the perceptions of primary school children about sun exposure and skin cancer, and the language they use about these Issues, as a basis for the design of health promotional materials. In all, 2857 children in five European countries took part in the study and were compared with 641 Australian children participating in a similar study, since the latter have been exposed to more intensive health education about the sun. The 'draw and write' technique was used. In Europe the level of awareness about the risks of excessive sun exposure and the need to protect the skin was considerably lower than in Australia, although there was some variation within northern Europe. Amongst the European children acknowledging a need to protect the skin, the principal means of protection quoted was the use of suncreams, with inadequate awareness of the value of clothing, hats and shade. European children expressed greater approval of suntans than did the Australian children. Some methodological problems were encountered as a result of nuances in the languages involved, emphasizing difficulties in international research of this type.

ISSN:0960-8931    

出版商:OVID    

年代:1997

数据来源: OVID