Roesch, Alexander and Becker, Bernd and Meyer, Stefanie and Wild, Peter and Hafner, Christian and Landthaler, Michael and Vogt, Thomas (2005) Retinoblastoma-binding protein 2-homolog 1: a retinoblastoma-binding protein downregulated in malignant melanomas. MODERN PATHOLOGY, 18 (9). pp. 1249-1257. ISSN 0893-3952,
Full text not available from this repository. (Request a copy)Abstract
In malignant melanomas, the loss of cell cycle control is thought to be due to a lack of retinoblastoma protein (pRb)-activity. Members of the previously described family of retinoblastoma-binding proteins (RBPs) are supposed to act as pRb-modulating factors. Based on RNA-fingerprinting of normal human melanocytes, we previously described a new family member with high sequence homology to the retinoblastoma-binding protein-2 (RBP-2), termed RBP2-Homolog 1 (RBP2-H1). Based on its UVB responsiveness, it was hypothesized that this gene may also play a role in melanocytic tumors. In the present study, we can confirm by real-time RT-PCR (six common melanocytic nevi, five advanced nodular melanomas and seven melanoma metastases) and immunohistochemistry (tissue microarrays: 52 melanocytic nevi, 60 melanomas, 60 metastases; and conventional sections: five common nevi, four advanced nodular melanomas, five melanoma metastases) that RBP2-H1 expression is progressively downregulated in advanced and metastatic melanomas in vivo with a certain intratumoral heterogeneity. Whereas benign melanocytic nevi are RBP2-H1 positive in about 70% of the cases, a lack of RBP2-H1 expression was found in 90% of the primary malignant melanomas and 70% of the melanoma metastases, respectively. Interestingly, a similar deficiency can be found in glioblastomas, but not epithelial cancers. In accordance to the in vivo data, established melanoma cell lines exhibit low but heterogeneous levels of RBP2-H1 expression. By co-immunoprecipitation, we provide the first evidence that a subfraction of total RBP2-H1 can bind to pRb, which makes this protein a true pRb-interacting factor. We conclude that loss of RBP2-H1 is a common finding in the progression of malignant melanomas. Since a direct interaction of RBP2-H1 and pRb seems possible, the loss of RBP2-H1 may possibly contribute to uncontrolled growth in malignant melanomas.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | BREAST-CANCER; GENE-PRODUCT; OF-VIEW; EXPRESSION; PLU-1; TRANSCRIPTION; TISSUES; EPHB6; RBP1; cell cycle; PLU-1; malignant melanoma; tumor progression |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Dermatologie und Venerologie Medicine > Lehrstuhl für Pathologie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 30 Apr 2021 08:57 |
| Last Modified: | 30 Apr 2021 08:57 |
| URI: | https://pred.uni-regensburg.de/id/eprint/35718 |
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