Melanoma stem cells promote metastasis via exosomal miR-1268a inactivation of autophagy

BACKGROUND: Metastatic melanoma has a high mortality rate and poor survival. This is associated with efficient metastatic colonization, but the underlying mechanisms remain elusive. Communication between cancer stem cells (CSCs) and cancer cells plays an important role in metastatic dissemination. Whether cancer stem cells can alter the metastatic properties of non-CSC cells; and whether exosomal crosstalk can mediate such interaction, have not been demonstrated in melanoma prior to this report. RESULTS: The results revealed that exosomes secreted by highly metastatic melanoma CSCs (OL-SCs) promoted the invasiveness of the low metastatic melanoma cells (OL) and accelerated metastatic progression. miR-1268a was up-regulated in cells and exosomes of OL-SCs. Moreover, OL-SCs-derived exosomal miR-1268a, upon taking up by OL cells, promoted the metastatic colonization ability of OL cells in vitro and in vivo. In addition, the pro-metastatic activity of exosomal miR-1268a is achieved through inhibition of autophagy. CONCLUSION: Our study demonstrates that OL cells can acquire the "metastatic ability" from OL-SCs cells. OL-SCs cells achieves this goal by utilizing its exosomes to deliver functional miRNAs, such as miR-1268a, to the targeted OL cells which in turn augments metastatic colonization by inactivating the autophagy pathway in OL cells.

NOP14 inhibits melanoma proliferation and metastasis by regulating Wnt/ß-catenin signaling pathway

Malignant melanoma is an aggressive skin cancer with a high mortality rate. Nucleolar protein 14 (NOP14) has been implicated in cancer development. However, the role of NOP14 in malignant melanoma progression remains largely unclear. In this study, we observed that malignant melanoma tissue showed NOP14 down-regulation compared to melanocytic nevi tissues. Moreover, we observed that NOP14 expression was significantly associated with melanoma tumor thickness and lymph node metastasis. NOP14 overexpression in melanoma cells suppressed proliferation, caused G1 phase arrest, promoted apoptosis, and inhibited melanoma cell migration and invasion. Further investigations revealed that NOP14 overexpression reduced the expression levels of Wnt3a, β-catenin, and GSK-3β of the Wnt/β-catenin pathway. In summary, we demonstrated that NOP14 inhibited melanoma cell proliferation and metastasis by regulating the Wnt/β-catenin signaling pathway.

Evaluation of nicotinamide as an anti-inflammatory and anti-angiogenic agent in uveal melanoma cell lines / Avaliação da nicotinamida como agente anti-inflamatório e anti-angiogênico em linhas celulares de melanoma uveal

ABSTRACT Purpose: To investigate the effect of nicotinamide on the secretion of pro-an giogenic and pro-inflammatory cytokines in uveal melanoma cell lines. Methods: Two human uveal melanoma cell lines (92.1 and OCM-1) were treated with nicotinamide (10 mmol/L) or control media for 48 hours in culture. The su perna tant from each culture was used in sandwich enzyme-linked immuno sorbent assay-based angiogenesis and inflammation arrays to evaluate the effects of exogenously administered nicotinamide on the secretion of a total of 20 pro-an gio genic and pro-inflammatory proteins. Results: Seven pro-angiogenic cytokines were detected under control conditions for both uveal melanoma cell lines. Treatment with nicotinamide resulted in a significant decrease in secretion of the following pro-angiogenic cytokines: angiogenin, angiopoietin-2, epidermal growth factor, and vascular epithelial growth factor-A in the 92.1 cells; basic fibroblast growth factor in the OCM-1 cells; and placenta growth factor in both cell lines. Among the pro-inflammatory proteins, monocyte chemotactic protein-1 and interleukin-8 were expressed in both untreated cell lines and both were significantly reduced when treated with nicotinamide. Conclusions: Results from this in vitro model suggest that nicotinamide may have anti-inflammatory and anti-angiogenic properties, which may open the possibility of using it as a chemopreventive agent for uveal melanoma; however, further studies including animal models are warranted.

RESUMO Objetivo: Acredita-se que a nicotinamida (NIC) seja capaz de diminuir a angiogênese induzida pelo fator de crescimento endotelial vascular (VEGF). Investigar os efeitos da nicotinamida sobre a secreção de citocinas pró-angiogênicas e pró-inflamatórias em linhagens de células de melanoma uveal humano (UM). Métodos: Duas linhagens de células humanas de UM (92,1 e OCM-1) foram tratadas com NIC (10 mmol/L) ou apenas com meio de cultura por 48 horas. O sobrenadante das culturas obtido após a administração de nicotinamida foi comparado com o sobrenadante das culturas controle quanto à expressão de 20 fatores pró-angiogênicos e pró-inflamatórios, pela técnica de enzyme-linked immunosorbent assay (ELISA). Resultados: Sete citocinas pró-angiogênicas foram detectadas nas condições de controle em ambas as linhagens de células de UM. O tratamento com nicotinamida promoveu uma redução significativa da secreção das seguintes citocinas angiogênicas: Angiogenina, ANG2, EGF e VEGF-A em células 92.1; bFGF em células OCM-1; PIGF em ambas as linhagens celulares. Quanto às proteínas pró-inflamatórias, a expressão de MCP-1 e IL-8 foi significativamente reduzida com a administração de nicotinamida em relação às culturas de células que não receberam o tratamento. Conclusões: Nicotinamida apresenta propriedades anti-inflamatórias e anti-angiogênicas em modelo experimental in vitro. Tais efeitos sugerem a possibilidade de utilizar esta substância na quimioprevenção do UM. Entretanto, estudos com modelos experimentais in vivo são necessários para melhor avaliar o benefício do tratamento do UM com nicotinamida.

Proton NMR characterization of intact primary and metastatic melanoma cells in 2D & 3D cultures

OBJECTIVE: To characterize the differences between the primary and metastatic melanoma cell lines grown in 2D cultures and 3D cultures. METHODS: Primary melanoma cells (WM115) and metastatic melanoma cells (WM266) extracted from a single donor was cultured in 2D as well as 3D cultures. These cells were characterized using proton NMR spectrometry, and the qualitative chemical shifts markers were identified and discussed. RESULTS: In monolayer culture (2D), we observed one qualitative chemical shift marker for primary melanoma cells. In spheroid cultures (3D), we observed nine significant chemical shifts, of which eight markers were specific for primary melanoma spheroids, whereas the other one marker was specific to metastatic melanoma spheroids. This study suggests that the glucose accumulation and phospholipid composition vary significantly between the primary and metastatic cells lines that are obtained from a single donor and also with the cell culturing methods. 14 qualitative chemical shift markers were obtained in the comparison between monolayer culture and spheroids cultures irrespective of the differences in the cell lines. Among which 4 were unique to monolayer cultures whereas 10 chemical shifts were unique to the spheroid cultures. This study also shows that the method of cell culture would drastically affect the phospholipid composition of the cells and also depicts that the cells in spheroid culture closely resembles the cells in vivo. CONCLUSION: This study shows the high specificity of proton NMR spectrometry in characterizing cancer cell lines and also shows the variations in the glucose accumulation and phospholipid composition between the primary and metastatic melanoma cell lines from the same donor. Differences in the cell culture method does plays an important role in phospholipid composition of the cells.

Piceatannol induced apoptosis through up-regulation of microRNA-181a in melanoma cells

BACKGROUND: Melanoma took top position among the lethal cancers and, despite there have been some great attempts made to increase the natural life of patients with metastatic disease, long-lasting and complete remissions are few. Piceatannol, owns the similar function as resveratrol, has been defined as an anti-cancer agent playing important role in inhibition of proliferation, migration and metastasis in various cancer. Thus, we aim to investigate the anti-cancer effect and mechanisms of piceatannol in melanoma cells. METHODS: Melanoma cell lines WM266-4 and A2058 were treated either with or without piceatannol. Cell viability and cell apoptosis were assessed by using MTT and Annexin V/PI assay, respectively. Cells were transfected with specific miRNA using Lipfectamine 2000. miRNA bingding ability to 3'-UTR region within specific gene was assed by firefly luciferase analysis. Gene and protein expression was eveluated by qRT-PCR and western blot analysis, respectively. RESULTS: Our study showed that piceatannol inhibited WM266-4 and A2058 cells growth and induced apoptosis. Totally, 16 differentially expressed miRNAs were screened out including 8 up-regulated and 8 down-regulated miRNAs. Expression level of miR-181a is significantly higher in piceatannol-treated cells than normal control and is lower in melanoma cancer tissues than its adjacent normal tissues. Bcl-2 is a target gene of miR-181a. Moreover, silencing of miR-181a reverses the decrease of cell viability induced by piceatannol in WM266-4 and A2058 cells. Taken together, present study uncovered the ability of piceatannol to repress melanoma cell growth and clarified the contribution of miR-181a in the anticancer role of piceatannol. CONCLUSION: The present study proposes that piceatannol can be taken into account to be a hopeful anticancer agent for melanoma.

Evaluación de reactividad inmunohistoquímica con método del Complejo Avidina­Biotina (ABC) / Evaluation of immunohistochemical reactivity with Avidin-Biotin Complex (ABC) method

Inmunohistoquímica es toda técnica que permite detectar in situ componentes celulares y extracelulares por medio de anticuerpos específicos, empleando sistemas de detección enzimáticos. Dentro de los métodos inmunohistoquímicos, la técnica del complejo avidina­biotina(ABC) es ampliamente utilizada debido a su alta sensibilidad. El objetivo del presente estudio fueevaluar la reactividad inmunohistoquímica del anticuerpo 4C4.9 para la detección de la proteínaS-100, utilizando el método ABC. Para la evaluación de la reactividad inmunohistoquímica se utilizaron 2 biopsias de piel humana con diagnóstico histopatológico de melanoma maligno nodular ulcerado y nevus melanocítico intradérmico, provenientes del Laboratorio de Investigación en Biotecnología Animal de la Universidad de La Frontera, Temuco, Chile. Se utilizó el Kit VECTASTAIN®como método de detección, la dilución del anticuerpo 4C4.9 fue 1/250 y la temperatura de incubación fue a 4 ºC ó 37 ºC por 18 horas. Para validar la técnica, se realizó un control positivo y otro negativo para 4C4.9. Los resultados de la tinción inmunohistoquímica por el método del complejo ABC mostraron tinción positiva para la proteína S-100, tanto en melanoma maligno nodular ulcerado, como en nevus melanocítico intradérmico, incubados durante 18 horas a 4 ºC ó 37 ºC. Sin embargo, la inmunotinción fue más intensa cuando el anticuerpo primario se incubó a 37 ºC. Para una correcta interpretación de los resultados, es necesario tener en consideración que la reacción antígeno-anticuerpo se ve influenciada por diversos factores, como la concentración del anticuerpo, el tiempo y la temperatura de incubación. En conclusión, nuestros resultados sugieren incubarlas muestras con el primer anticuerpo (4C4.9) en una dilución de 1/250 en agua destilada, incu-bando durante 18 h a 37 ºC. Se recomienda la utilización del anticuerpo 4C4.9 como apoyo al diagnóstico y diagnóstico diferencial.

Immunohistochemistry is anytechnique that can detect cellular and extracellular components in situ by means of specific antibodies,using enzymatic detection systems. Among immunohistochemical methods, the technique ofavidin - biotin complex (ABC) is widely used because of its high sensitivity. The aim of this study was to evaluate the immunohistochemical reactivity of the4C4.9 antibody for detection of S-100 protein using the ABC method. For the evaluation ofimmunohistochemical reactivity 2 biopsies of humanskin were used with histopathological diagnosis ofulcerated malignant melanoma and melanocyticintradermal nevi from the Research Laboratory onAnimal Biotechnology of the Universidad de La Fron-tera, Chile. The Kit VECTASTAIN® was used asdetection method, the dilution the 4C4.9 antibodywas 1/250 and incubation temperature was at 4 °Cor 37 °C for 18 hours. To validate the technique, apositive control and a negative for 4C4.9 was performed. The results of immunohistochemicalstaining by the method of ABC complex showed positive staining for protein S-100 both in ulcerated malignant melanoma and melanocytic intradermalnevi, incubated for 18 hours at 4 °C or 37 °C.However, immunostaining was more intense when the primary antibody was incubated at 37° C. For acorrect interpretation of the results, it is necessary to take into consideration that the antigen-antibody reaction is influenced by various factors such as the concentration of antibody, time and temperature ofincubation. In conclusion, our results suggest incubating the samples with the first antibody (4C4.9)at 1/250 dilution in distilled water, incubating for 18h at 37 ºC. However, immunostaining was moreintense when the primary antibody was incubated at37° C. For a correct interpretation of the results, it isnecessary to take into consideration that antigen-antibody reaction is influenced by various factors suchas the concentration of antibody, time and temperature of incubation. In conclusion, our results suggest incubating the samples with the first antibody(4C4.9) at 1/250 dilution in distilled water, incubating for 18 h at 37 ºC. The use of the antibody 4C4.9 is recommended to support the diagnosis and differential diagnosis.

Inhibitory Effect of Melanoma Differentiation Associated Gene-7/Interleukin-24 on Invasion In Vitro of Human Melanoma Cancer Cells

The acquisition of metastasis potential is a critical point for malignant tumors. Melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24) is a potential tumor suppress gene and frequently down-regulated in malignant tumors. It has been implicated that overexpression of MDA-7 led to proliferation inhibition in many types of human tumor. Invasion is an important process which is potential to promote tumor metastasis. However, the role and potential molecular mechanism of mda-7/IL-24 to inhibit the invasion of human melanoma cancer is not fully clear. In this report, we identified a solid role for mda-7/IL-24 in invasion inhibition of human melanoma cancer LiBr cells, including decreasing of adhesion and invasion in vitro, blocking cell cycle, down-regulating the expression of ICAM-1, MMP-2/9, CDK1, the phosphorylation of ERK and Akt, NF-kappaB and AP-1 transcription activity. Meanwhile, there was an increased expression of PTEN in mda-7/IL-24 over-expression LiBr cells. Our results demonstrated that mda-7/IL-24 is a potential invasion suppress gene, which inhibits the invasion of LiBr cells by the down-regulation of ICAM-1, MMP-2/9, PTEN, and CDK1 expression. The molecular pathways involved were the MAPK/ERK, PI3K-Akt, NF-kappaB, and AP-1. These findings suggest that mda-7/IL-24 may be used as a possible therapeutic strategy for human melanoma cancer.

Subretinal lipid exudation associated with untreated choroidal melanoma.

Subretinal lipid exudation in an untreated choroidal melanoma is very rare. It is seen following plaque radiotherapy in choroidal melanoma. There is only one case report of untreated choroidal melanoma with massive lipid exudation in a patient with metastatic hypernephroma. We report here a rare case of untreated choroidal melanoma with lipid exudation. Subretinal exudation that is rarely seen following plaque brachytherapy was noted at the borders of this untreated tumor. Lipid exudation partially resolved following brachytherapy.

Procoagulant properties of human MV3 melanoma cells

A correlation between cancer and prothrombotic states has long been described. More recently, a number of studies have focused on the procoagulant mechanisms exhibited by tumor cells. In the present study, we dissected the molecular mechanisms responsible for the procoagulant activity of MV3, a highly aggressive human melanoma cell line. It was observed that tumor cells strongly accelerate plasma coagulation as a result of: i) expression of the blood clotting initiator protein, a tissue factor, as shown by flow cytometry and functional assays (factor Xa formation in the presence of cells and factor VIIa), and ii) direct activation of prothrombin to thrombin by cells, as evidenced by hydrolysis of the synthetic substrate, S-2238, and the natural substrate, fibrinogen. This ability was highly potentiated by the addition of exogenous factor Va, which functions as a co-factor for the enzyme factor Xa. In contrast, prothrombin activation was not observed when cells were previously incubated with DEGR-factor Xa, an inactive derivative of the enzyme. Moreover, a monoclonal antibody against bovine factor Xa reduced the prothrombin-converting activity of tumor cells. In conclusion, the data strongly suggest that MV3 cells recruit factor Xa from the culture medium, triggering an uncommon procoagulant mechanism.

Selective expression of progesterone receptor in malignant melanoma was inversely correlated with PCNA / 华中科技大学学报（医学）（英德文版）

To investigate the role of progesterone receptor (PR) expression in malignant melanoma (MM), PR and proliferative cell nuclear antigen (PCNA) expression were immunohistochemistrically evaluated in a series of 35 specimens of MM, and the correlation between the immunohistochemistrical findings and clinicopathological data was also analyzed. PR expression was detected in 25.7% (9/35) of the patients with MM. No PR expression was observed in nevi. PR expression was inversely correlated with PCNA expression (r=-0.353, P=0.026). PR expression was slightly increased in females, subjects aged under 55 y, those with ulceration, non-acral subtype and diagnosis delay longer than 1 y, but the difference was not statistically significant. Selective expression of progesterone receptor in malignant melanoma might be correlated with inhibited tumor growth.

The expression of endothelin receptor B in melanoma cells A375 and Sk-mel-1 and the proliferative effects of endothelin 3 on A375 cells / 华中科技大学学报（医学）（英德文版）

In order to investigate the expression of endothelin receptor B (ETR-B) in human malignant melanoma (MM) cells A375 and SK-mel-1 and the proliferative effects of endothelin 3 (ET3) on A375 cells, RT-PCR was applied to detect the expression of ETR-B gene in human MM cells A375 and SK-mel-1. MTT method was used to evaluate the growth enhancing effects of ET3 on A375 cell line in vitro. The results showed that ETR-B gene was expressed in both MM A375 and SK-mel-1 cells. ET3 had stronger ability to enhance the proliferation of A375 cells in vitro in a concentration-dependent manner. It was suggested that ET3/ETR-B might play an important proliferative role in MM.

Tetraspanin CD9 induces MMP-2 expression by activating p38 MAPK, JNK and c-Jun pathways in human melanoma cells

Expression of matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9), which correlates with tumor invasion and metastasis, has been known to be regulated by several intracellular signaling pathways. Since the CD9 membrane protein has been implicated in signal transduction and malignant progression of cancer cells, we examined the functional involvement of CD9 in the regulation of MMP-2 and MMP-9 expression by using stable CD9 transfectant clones of MelJuso human melanoma cells. The CD9 cDNA-transfected cells with elevated CD9 expression displayed increased MMP-2 and decreased MMP-9 expression when compared with the mock transfectant cells. Among several signal pathway inhibitors tested, SB203580 and SP600125, which inhibit p38 MAPK and JNK respectively, completely blocked the CD9-stimulated MMP-2 expression. Phosphorylation levels of p38 MAPK and c-Jun in MelJuso cells were also significantly increased by CD9 transfection. In addition, the down-regulation of p38 MAPK and JNK by siRNA transfection resulted in a decrease in MMP-2 expression by MelJuso cells. Promoter analysis and gel shift assay showed that the CD9-induced MMP-2 expression is mediated by a functional AP-1 site through interactions with AP-1 transcription factors including c-Jun. These results suggest that CD9 induces MMP-2 expression by activating c- Jun through p38 MAPK and JNK signaling pathways in human melanoma cells.

IL-1beta Acts in Synergy with Endogenous IL-1beta in A375-S2 Human Melanoma Cell Apoptosis Through Mitochondrial Pathway

Interleukin-1beta (IL-1beta) is a pivotal proinflammatory cytokine. To investigate the mechanism of IL-1beta-induced cell death in human malignant melanoma A375-S2 cells, MTT assay, photomicroscopical observation, DNA agarose gel electrophoresis, radioimmunoassay and Western blot analysis were carried out. IL-1beta did not only induce nuclear condensation and DNA fragmentation, but also increased degradation of two substrates of caspase-3, poly ADP-ribose polymerase (PARP) and inhibitor of caspase-activated DNase (ICAD). Simultaneously, release of precursor of IL-1beta (pro-IL-1beta) and endogenous IL-1beta production were involved in the apoptotic process. IL-1beta enhanced the ratio of Bax/Bcl-2 and Bax/Bcl-xL expression and up-regulated apoptosis inducing factor (AIF) expression, which required the activation of downstream caspases. These results suggest that IL-1beta induces endogenous IL-1beta production, enhances cleavage of caspase downstream substrates and promotes mitochondria mediated apoptosis in A375-S2 cells.

Human placental lipid induces mitogenesis and melanogenesis in B16F10 melanoma cells.

A hydroalcoholic extract of fresh term human placenta was found to be mitogenic as well as melanogenic on B16F10 mouse melanoma in an in vitro culture. The extract, a reservoir of a large number of bioactive molecules, was resolved to get the lipid fraction. Its activity was evaluated on B16F10 mouse melanoma by assessing the change in cellular morphology, growth and melanin induction. The lipid fraction, placental total lipid fraction (PTLF) tested in the study employed doses of 0 01 to 200 microg/ml; optimum growth and melanization accompanied by morphological changes were recorded at 10 and 100 microg/ml respectively. At intermediate doses growth and melanization were found to show a pattern of change over between growth and melanization and finally reached at an inverse relation at the respective optimal dose of response. Compared with defined sphingolipids, C(2) ceramide and sphingosine-1-phosphate, the results were mostly corroborative. The duality of biological response of sphingolipids as reported in numerous studies was comparable for the PTLF suggesting that its active component is a sphingolipid and showing its use for pigment recovery in vitiligo.

Biología molecular y mocrometástasis del melanoma cutáneo / Molecular biology and micrometastasis in cutaneous melanoma

Las controversias en el manejo de la enfermedad ganglionar ha permanecido en discusión desde hace 20 años. Los recientes avances tecnológicos en biología molecular y las nuevas técnicas quirúrgicas mediante la detección del ganglio centinela han permitido identificar con mayor precisión un grupo seleccionado de pacientes que se habrán de beneficiar en el control local de la enfermedad y en la supervivencia, al efectuarse disecciones ganglionares de manera electiva ante la presencia de metástasis ganglionar microscópica y con la administración de terapias sistémicas ante la detección temprana de micrometástasis a distancia. Mediante el empleo de los marcadores de membrana de las células con melanoma, el uso de anticuerpos monoclonales nos permiten identificar el fenotipo de las lesiones melanocíticas, que pueden ser empleadas en inmunohistopatología e inmunocentellografía. Finalmente, el advenimiento de las técnicas de transcriptasa reversa, aunado a las de la reacción en cadena de polimerasa, ha permitido una mayor sensibilidad en la detección de la enfermedad micrometastásica, modificándose de manera significativa y haciendo má precisa la estadificación de los pacientes con melanoma. El empleo de estas técnicas es factible en nuestro medio por su costo y sencillez. Con base en ellas es posible diagnosticar micrometástasis en aproximadamente el 33 por ciento de pacientes clasificados en estadio I (lesiones < 0.76 mm), en quienes no se identificarían metástasis ganlgionares mediante técnicas de hematoxilina eosina. El 50 por ciento de estos enfermos podrían recibir una terapia locorregional más agresiva con el consecuente beneficio en la supervivencia. Sin embargo, en la actualidad, estas técnicas únicamente son empleadas de manera rutinaria en estudios protocolizados

Rol del gen SPARC en la capacidad tumorigénica de células de melanoma humano / The role of SPARC gene in tumorigenic capacity of human melanoma cells

En un estudio previo demostramos que líneas celulares y tumores de melanoma humano expresan altos niveles de la proteína de matriz extracelular SPARC. Para determinar su rol en la progresión del melanoma humano, la línea IIB-MELLES fue transfectada con el cDNA de SPARC anti-sentido. Se aislaron tres clones con expresión disminuida de SPARC. Ninguno de ellos mostró cambios en la cinética de crecimiento in vitro comparado con las células control. La inyección s.c. de células control en ratones atímicos mostró desarrollo tumoral en el 100 por ciento de los animales, mientras que ninguno de los clones dio origen a tumores. Estos estudios demuestran que SPARC podría jugar un rol central en la progresión del melanoma humano.

Energy balance in subcutaneous melanoma-bearing mice

Energy balance of control and melanoma-bearing mice was determined after 15 days of controlled food intake. Body and tumor energy contents were evaluated after preparing the materials for bomb calorimetry. Neither energy intake nor expenditure was different between control and melanoma mice. Body energy gain was lower in melanoma mice, but including tumor energy both groups had similar energy gain during the experimental period. It is concluded that a two-week skin melanoma did not seriously affect the energy balance of mice, and that tumor growth was achieved by utilizing body energy without promoting any increase in energy intake.

Induction of ICAM-1 and HLA-DR expression by IFN-gamma in malignant melanoma cell lines

Two human malignant melanoma cell lines, Malme-3M and SK-Mel-28, were analyzed for their ability to induce the expression of intercellular adhesion molecule 1 (ICAM-1) and human leukocyte antigen (HLA)-DR molecules on their cell surfaces as well as at the transcriptional level before and after treatment with interferon (IFN)-gamma. Both cell lines demonstrated a high percentage(> 99%) of ICAM-1 expression regardless of IFN-gamma treatment. Before IFN-gamma treatment, Malme-3M cells barely expressed HLA-DR molecules ( 50%) of HLA-DR expression. Both cell lines displayed elevated levels of HLA-DR expression in a time dependent manner after IFN-gamma treatment. However, these two cell lines have been shown to respond differentially to IFN-gamma. The molecular mechanism underlying such a differential behavior was investigated, and HLA-DR gene regulation was studied at the transcriptional level. Treatment with IFN-gamma led to the steady-state mRNA augmentation of the HLR-DR gene. The HLA-DRA mRNA augmentation was similar in both cell lines, whereas in Malme-3M, IFN-gamma did not augment the rate of transcription of the HLA-DRB gene as much as in SK-Mel-28. Data from this study established the fact that the melanoma cell lines displayed a differential susceptibility to IFN-gamma on the modulation of HLA-DR molecules, and this modulation was transcriptionally regulated.

Cobre: consideraciones biologicas; su utilidad como marcador tumoral de melanomas / Copper: biologic considerations; it`s use as a tumor marker for melanomas

Se resumen los niveles séricos de Cobre (Cu) y Ceruloplasmina (Cp) en medicina general y particularmente en diversos procesos malignos y benignos. Se menciona la hipótesis que vincula las metástasis, el crecicmiento tumoral y la angiogénesis concomitante con la elevación del Cu sérico. Se mensionan los resultados obtenidos en 20 pacientes con melanoma maligno concluyendo que para el Estadio I una elevación brusca de Cu sérico obliga a pensar en una sistematización del proceso oncológico