Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0278883 (metastatic melanoma)
 6,224 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Melanoma tumors and cultured cell lines are relatively resistant to the cytotoxic effects of ionizing radiation, thereby limiting the use of radiotherapy for the clinical treatment of melanoma. New strategies for sensitizing melanoma cells therefore deserve examination. In an attempt to identify and target signaling pathways that contribute to radioresistance, we investigated the role of nuclear factor-kappaB (NF-kappaB), a transcription factor known to inhibit apoptosis induced by a variety of stimuli and promote radioresistance. Two human metastatic melanoma cell lines, A375 and MeWo, were used to examine the radiosensitizing effects of inhibitors of the NF-kappaB pathway. Nuclear extracts from these cell lines were tested for active NF-kappaB using the electrophoretic mobility shift assay. Both melanoma cell lines had constitutively activated NF-kappaB as observed by electrophoretic mobility shift assay. In an attempt to reverse NF-kappaB activity, cells were treated either with vehicle alone (DMSO) or with a proteasome inhibitor Z-Leu-Leu-Leu-H (MG132; 10 micromol/L for 2 hours prior to irradiation) that inhibited both constitutive and radiation-induced NF-kappaB activity. The clonogenic cell survival assay showed that pretreatment with MG132 enhanced tumor cell radiosensitivity with the survival factor at 2 Gy being reduced from 48 +/- 0.8% and 48 +/- 1.6% in vehicle-treated cells to 27.7 +/- 0.32% and 34.3 +/- 0.7% in MG132-treated MeWo and A375 cells, respectively. To test the role of NF-kappaB in radioresistance more directly, MeWo cells were stably transfected with a dominant-negative mutant IkappaBalpha construct, which led to the inhibition of both constitutive and radiation-induced NF-kappaB activity. A modest restoration of radiosensitivity was also observed in the stably transfected MeWo cells with survival factor at 2 Gy values being reduced from 47 +/- 0.8% in parental MeWo cells to 32.9 +/- 0.7% in stable transfectants. Because constitutively activated mitogen-activated protein kinase kinase (MEK) pathway has been shown to lead to activated NF-kappaB, we wanted to determine the relative contribution of activated MEK in the human melanoma cells. To test this, MeWo and A375 melanoma cells were exposed to the MEK inhibitor PD184352. Treatment with PD184352 partially reversed NF-kappaB activity but did not impart radiation sensitivity to these cells. Our results indicate that activated NF-kappaB may be one of the pathways responsible for the radioresistance of melanoma cells and that strategies for inhibiting its influence may be useful in restoring the radioresponse of melanomas.
 ...
PMID:Inhibition of constitutively activated nuclear factor-kappaB radiosensitizes human melanoma cells. 1529 81

Dimethyl sulphoxide (DMSO) is widely used as a solvent in biomedical research, regularly in concentrations up to 1%. Nevertheless, little is known about the effect of different DMSO concentration on WM-266-4 metastatic melanoma cells, which are often used in melanoma research. Due to resistance of melanoma cells high concentrations of cytotoxic substances soluble in DMSO are used in vitro tests. Consequently, total DMSO concentration often exceeds 1%. The aim of our study was to test the metabolic activity and morphology of WM-266-4 cells exposed to selected DMSO concentrations for different period of time. Cells were incubated in selected ethanol concentrations for comparison. MTT test was performed to determine proliferation activity of the cells and morphological analysis was carried out by phase-contrast microscopy. Our results show inhibitory effect of DMSO on WM-266-4 cells' metabolic activity. Morphology of the cells changed progressively with the time of exposure. Ethanol showed little effect on metabolic activity of the cells and no effect on cell morphology after selected period of time. According to our study, for specific in vitro tests concentrations of DMSO up to 1.5% may be appropriate for WM-266-4 cell line experiments.
 ...
PMID:The influence of dimethyl sulfoxide (DMSO) on metabolic activity and morphology of melanoma cell line WM-266-4. 3021 98