During human melanoma progression AP-1 binding pairs are altered with loss of c-Jun in vitro.

Abstract

We demonstrated previously that c-Jun, JunB and c-Fos RNA were dysregulated in metastatic melanoma cells compared with normal human melanocytes. The purpose of this study was to evaluate the distribution in composition of AP-1 dimers in human melanoma pathogenesis. We investigated AP-1 dimer pairing in radial growth phase-like (RGP) (w3211) and vertical growth phase-like (VGP) (w1205) human melanoma cells and metastatic cell lines (cloned from patients, c83-2c, c81-46A, A375, respectively) compared with melanocytes using electrophoretic mobility shift assay (EMSA), Western blot and transfection analyses. There are progressive variations in AP-1 composition in different melanoma cell lines compared with normal melanocytes, in which c-Jun, JunD and FosB were involved in AP-1 complexes. In w3211, c-Jun, JunD and Fra-1 were involved in AP-1 binding, while in w1205, overall AP-1 binding activity was decreased significantly and supershift binding was detected only with JunD antibodies. In metastatic c81-46A and A375 cells, only JunD was involved in AP-1 binding activity, but in a third (c83-2c) c-Jun, JunD and Fra-1 were present. Western blot evaluation detected c-Jun in melanocytes and w3211, but this component was decreased significantly or was not detectable in w1205, c81-46A and A375 cells. In contrast, JunD protein was elevated in c81-46A and c83-2c cells compared with melanocytes and RGP and VGP cell lines. Normal melanocytes and c83-2c cells (which have c-Jun involved in AP-1 binding), transfected with c-Jun antisense and treated with cisplatin, showed higher viability compared with untransfected cells, while in c81-46A cells (in which only JunD is detectable) no change in cell viability was observed following treatment with cisplatin and c-jun antisense transfection. A dominant-negative c-Jun mutant (TAM67) significantly increased the soft agar colony formation of w3211 and c83-2c cells. These results suggest that components of AP-1, especially c-Jun, may offer a new target for the prevention or treatment of human melanoma progression.

• Authors: Sun Yang, Susan McNulty, Frank L Meyskens Jr
• Journal: Pigment cell research (Pigment Cell Res) Vol. 17 Issue 1 Pg. 74-83 (Feb 2004) ISSN: 0893-5785 [Print] Denmark
• PMID: 14717848 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• DNA-Binding Proteins
• Nuclear Proteins
• Oligoribonucleotides, Antisense
• Proto-Oncogene Proteins c-jun
• Transcription Factor AP-1
• Transcription Factors

Topics

• Cells, Cultured
• DNA-Binding Proteins (metabolism)
• Humans
• Melanocytes (cytology, metabolism)
• Melanoma (metabolism)
• Nuclear Proteins (metabolism)
• Oligoribonucleotides, Antisense
• Promoter Regions, Genetic (physiology)
• Protein Binding
• Proto-Oncogene Proteins c-jun (drug effects, metabolism)
• Transcription Factor AP-1 (genetics, metabolism)
• Transcription Factors (metabolism)
• Transcriptional Activation (physiology)