Bone morphogenic proteins are overexpressed in malignant melanoma and promote cell invasion and migration

University of Regensburg Medical School, Regensburg, Germany.
Cancer Research (Impact Factor: 9.33). 02/2005; 65(2):448-56.
Source: PubMed

ABSTRACT Malignant melanoma cells are known to have altered expression of growth factors compared with normal human melanocytes. These changes probably favor tumor growth and progression and influence the tumor environment. The induction of transforming growth factor beta1 (TGF-beta1), TGF-beta2, and TGF-beta3 expression in malignant melanoma has been reported before, whereas the expression of related bone morphogenic protein (BMP) molecules has not been analyzed in melanomas until now. Here, we show that BMP4 and BMP7 are up-regulated in nine melanoma cell lines, whereas BMP2 is overexpressed in only two of the analyzed cell lines. Immunohistochemistry of primary and metastatic melanoma also shows increased BMP4 and BMP7 expression compared with nevi. Promoter studies reveal that expression is controlled at the transcriptional level. The transcription factor Ets-1 was identified as a positive regulator for BMP4 expression. In order to determine the functional relevance of BMP expression in malignant melanoma, chordin-expressing cell clones and antisense BMP4 cell clones were generated. The clones in which BMP4 activity and expression are reduced show no changes in proliferation or in attachment-independent growth when compared with controls. However, a strong reduction of migratory and invasive properties was observed in these cells, suggesting that BMP4 promotes melanoma cell invasion and migration and therefore has an important role in the progression of malignant melanoma.

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Available from: Anja Katrin Bosserhoff, Apr 07, 2014
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    • "Studies analyzing 25 tongue squamous cell carcinomas by gene microarray and qPCR analyses revealed that BMP-2 gene expression may be associated with lymph node metastasis [17]. In addition, ectopic expression of BMP-2 stimulated angiogenesis in developing tumors and resulted in significantly increased local invasion and metastasis in melanoma [18], [19], lung cancer cells [20], [21], and breast cancer cells [22]. However, findings of these previous studies are insufficient for revealing the role of BMP-2 and its mechanism related to oral cancer progression. "
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    ABSTRACT: Bone morphogenetic protein-2 (BMP-2)-containing bone grafts are useful regenerative materials for oral and maxillofacial surgery; however, several in vitro and in vivo studies previously reported cancer progression-related adverse effects caused by BMP-2. In this study, by quantifying the rhBMP-2 content released from bone grafts, the rhBMP-2 concentration that did not show cytotoxicity in each cell line was determined and applied to the in vitro monoculture or coculture model in the invasion assay. Our results showed that 1 ng/ml rhBMP-2, while not affecting cancer cell viability, significantly increased the invasion ability of the cancer cells cocultured with fibroblasts. Cocultured medium with rhBMP-2 also contained increased levels of matrix metalloproteinases. rhBMP-2-treated cocultured fibroblasts did not show a prominent difference in mRNA expression profile. Some cytokines, however, were detected in the conditioned medium by a human cytokine antibody array. Among them, the cancer invasion-related factor CCL5 was quantified by ELISA. Interestingly, CCL5 neutralizing antibodies significantly reduced the invasion of oral cancer cells. In conclusion, our results suggest that 1 ng/ml rhBMP-2 may induce invasion of oral squamous cell carcinoma (OSCC) cells by CCL5 release in coculture models. Therefore, we propose that a careful clinical examination before the use of rhBMP-2-containing biomaterials is indispensable for using rhBMP-2 treatment to prevent cancer progression.
    PLoS ONE 10/2014; 9(10):e108170. DOI:10.1371/journal.pone.0108170 · 3.23 Impact Factor
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    • "This could be of particular importance for cancer therapy because activating mutations in p110α are frequently found in human cancers, and p55γ is differentially up-regulated in several tumours, which is sufficient to stimulate tumour angiogenesis [45]. This, together with the crucial role of BMP2 in oncogenic transformation and tumour angiogenesis [46-48], suggests that the p55γ/p110α complex positively regulates BMP2-induced motility, chemotaxis, and invasion of endothelial and cancer cells [9,49,50]. Whether the PI3K p55γ/p110α dimer indeed represents an attractive molecular target to interfere with BMP2-related cancers will require intense investigations in future. "
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    ABSTRACT: Background BMP-induced chemotaxis of mesenchymal progenitors is fundamental for vertebrate development, disease and tissue repair. BMP2 induces Smad and non-Smad signalling. Whereas signal transduction via Smads lead to transcriptional responses, non-Smad signalling induces both, transcriptional and immediate/early non-transcriptional responses. However, the molecular mechanisms by which BMP2 facilitates planar cell polarity, cortical actin rearrangements, lamellipodia formation and chemotaxis of mesenchymal progenitors are poorly understood. Our aim was to uncover the molecular mechanism by which BMP2 facilitates chemotaxis via the BMP2-dependent activation of PI3K and spatiotemporal control of PIP3 production important for actin rearrangements at the mesenchymal cell cytocortex. Results We unveiled the molecular mechanism by which BMP2 induces non-Smad signalling by PI3K and the role of the second messenger PIP3 in BMP2-induced planar cell polarity, cortical actin reorganisation and lamellipodia formation. By using protein interaction studies, we identified the class Ia PI3K regulatory subunit p55γ to act as a specific and non-redundant binding partner for BMP receptor type II (BMPRII) in concert with the catalytic subunit p110α. We mapped the PI3K interaction to a region within the BMPRII kinase. Either BMP2 stimulation or increasing amounts of BMPRI facilitated p55γ association with BMPRII, but BMPRII kinase activity was not required for the interaction. We visualised BMP2-dependent PIP3 production via PI3K p55γ/p110α and were able to localise PIP3 to the leading edge of intact cells during the process of BMP2-induced planar cell polarity and actin dependent lamellipodia formation. Using mass spectrometry, we found the highly PIP3-sensitive PH-domain protein LL5β to act as a novel BMP2 effector in orchestrating cortical actin rearrangements. By use of live cell imaging we found that knock-down of p55γ or LL5β or pharmacological inhibition of PI3K impaired BMP2-induced migratory responses. Conclusions Our results provide evidence for an important contribution of the BMP2-PI3K (p55γ/p110α)- PIP3-LL5β signalling axis in mesenchymal progenitor cell chemotaxis. We demonstrate molecular insights into BMP2-induced PI3K signalling on the level of actin reorganisation at the leading edge cytocortex. These findings are important to better understand BMP2–induced cytoskeletal reorganisation and chemotaxis of mesenchymal progenitors in different physiological or pathophysiological contexts.
    BMC Biology 05/2014; 12(1):43. DOI:10.1186/1741-7007-12-43 · 7.98 Impact Factor
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    • "containing polycarbonate filters with 8-mm pore size (Costar, Bodenheim, Germany), essentially as described previously (Rothhammer et al, 2005). Filters were coated with gelatin (5 mg l À 1 ). "
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    ABSTRACT: Background: Processing of microRNAs (miRNAs) is a highly controlled process. Deregulation of miRNA expression was observed in several types of cancer but changes in the miRNA-processing enzymes have not been analysed until today. In this study, we analysed Argonaute2 (AGO2, EIF2C2), as one main factor of the miRNA processing ensemble, in the context of cancer development, especially in melanoma. Methods: We determined the AGO2 expression level in melanoma, as well as in other cancers, with biochemical approaches (qRT–PCR, western blot and immunofluorescence studies) and analysed the cell behaviour in migration assays. Results: Specifically in melanoma, we revealed a strong reduction of AGO2 expression compared with primary melanocytes. The reduction of AGO2 expression was only found on protein level, whereas the mRNA level stayed unchanged hinting to post-transcriptional regulation. We could show that re-expression of AGO2 in melanoma leads to a strong improvement of regulatory effects due to increased functionality of small-interfering RNAs and short hairpin RNAs. Conclusion: We identified melanoma-specific downregulation of AGO2 and corresponding reduced RNAi efficiency. These findings will help to understand the molecular basis of malignant melanoma and can potentially lead to an improvement of therapeutic strategies.
    British Journal of Cancer 10/2013; 109(12). DOI:10.1038/bjc.2013.646 · 4.84 Impact Factor
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