Bone Morphogenetic Proteins BMP-4 Research Articles

Osteogenic and Adipogenic Differentiation Potential of Oral Cancer Stem Cells May Offer New Treatment Modalities

(1) Treatment failure of oral squamous cell carcinoma (OSCC) is generally due to the development of therapeutic resistance caused by the existence of cancer stem cells (CSCs), a small cell subpopulation with marked self-renewal and differentiation capacity. Micro RNAs, notably miRNA-21, appear to play an important role in OSCC carcinogenesis. Our objectives were to explore the multipotency of oral CSCs by estimating their differentiation capacity and assessing the effects of differentiation on stemness, apoptosis, and several miRNAs' expression. (2) A commercially available OSCC cell line (SCC25) and five primary OSCC cultures generated from tumor tissues obtained from five OSCC patients were used in the experiments. Cells harboring CD44, a CSC marker, were magnetically separated from the heterogeneous tumor cell populations. The CD44+ cells were then subjected to osteogenic and adipogenic induction, and the specific staining was used for differentiation confirmation. The kinetics of the differentiation process was evaluated by qPCR analysis of osteogenic (Bone Morphogenetic Protein-BMP4, Runt-related Transcription Factor 2-RUNX2, Alkaline Phosphatase-ALP) and adipogenic (Fibroblast Activation Protein Alpha-FAP, LIPIN, Peroxisome Proliferator-activated Receptor Gamma-PPARG) markers on days 0, 7, 14, and 21. Embryonic markers (Octamer-binding Transcription Factor 4-OCT4, Sex Determining Region Y Box 2-SOX2, and NANOG) and micro RNAs (miRNA-21, miRNA-133, and miRNA-491) were also correspondingly evaluated by qPCR. An Annexin V assay was used to assess the potential cytotoxic effects of the differentiation process. (3) Following differentiation, the levels of markers for the osteo/adipo lineages showed a gradual increase from day 0 to day 21 in the CD44+ cultures, while stemness markers and cell viability decreased. The oncogenic miRNA-21 also followed the same pattern of gradual decrease along the differentiation process, while tumor suppressor miRNA-133 and miRNA-491 levels increased. (4) Following induction, the CSCs acquired the characteristics of the differentiated cells. This was accompanied by loss of stemness properties, a decrease of the oncogenic and concomitant, and an increase of tumor suppressor micro RNAs.

Intrinsically disordered BMP4 morphogen and the beak of the finch: Co-option of an ancient axial patterning system

Darwin's finches, with the primary diversity in the shape and size of their beaks, represent an excellent model system to study speciation and adaptive evolution. It is generally held that evolution depends on the natural selection of heritable phenotypic variations originating from the genetic mutations. However, it is now increasingly evident that epigenetic transgenerational inheritance of phenotypic variation can also guide evolutionary change. Several studies have shown that the bone morphogenetic protein BMP4 is a major driver of beak morphology. A recent study explored variability of the morphological, genetic, and epigenetic differences in the adjacent “urban” and “rural” populations of two species of Darwin's finches on the Galápagos Islands and revealed significant changes in methylation patterns in several genes including those involved in the BMP/TGFß pathway in the sperm DNA compared to erythrocyte DNA. These observations indicated that epigenetic changes caused by environmental fluctuations can be passed on to the offspring. Nonetheless, the mechanism by which dysregulated expression of BMP4 impacts beak morphology remains poorly understood. Here, we show that BMP4 is an intrinsically disordered protein and present a causal a link between epigenetic changes, BMP4 dysregulation and the evolution of the beak of the finch by natural selection.

Hormones and dentistry: a two-way relationship.

Stem cells of dental pulp (SCDPs) are multipotent stem cells with the potential to differentiate into various cell types. For this reason, they have been proposed as an alternative source for mesenchymal stem cells. Somatostatin (ST) is a peptide hormone with an inhibitory effect on several endogenous hormones. The aim of our study is to investigate whether somatostatin can promote or inhibit differentiation of SCDPs in osteoblasts and bone tissue. SCDPs were extracted from third molars of healthy subjects and were treated with ST at the concentration of 100 ng/ml for 24 and 48 h. Gene expression in treated SCDPs was compared with untreated cells (control) to check the effect of somatostatin on stem cell differentiation. After 24 h of treatment many genes investigated were downregulated in treated SCDPs vs untreated SCDPs. Significantly up-regulated gene (Fold change >2) was the Bone Morphogenetic Protein BMP4. On the contrary ST induced the over-expression of bone related genes after 48 h of treatment. TGFB family genes and their receptors were also significantly upregulated after 48 h of treatment. ST demonstrated to promote the self-renewal of SCDPs: in our experiments somatostatin mainly acted on TGFB family genes. Further studies are needed to explore this new way of creating bone tissue.

Effects of airborne particulate matter on alternative pre-mRNA splicing in colon cancer cells

Alternative pre-mRNA splicing plays key roles in determining tissue- and species-specific cell differentiation as well as in the onset of hereditary disease and cancer, being controlled by multiple post- and co-transcriptional regulatory mechanisms. We report here that airborne particulate matter, resulting from industrial pollution, inhibits expression and specifically affects alternative splicing at the 5′ untranslated region of the mRNA encoding the bone morphogenetic protein BMP4 in human colon cells in culture. These effects are consistent with a previously reported role for BMP4 in preventing colon cancer development, suggesting that ingestion of particulate matter could contribute to the onset of colon cell proliferation. We also show that the underlying mechanism might involve changes in transcriptional elongation. This is the first study to demonstrate that particulate matter causes non-pleiotropic changes in alternative splicing.

Bone morphogenetic protein Bmp4 overexpression is not associated to Smad4 expression in oral cancer

In order to evaluate the expression of bone morphogenetic protein 4 (BMP-4) and its intracellular mediator SMAD4 in oral cancer, a study was performed on 91 oral squamous cell carcinoma (SCC) and 21 metastatic lymph node archival specimens. Nine specimens of benign oral mucosa lesions were included as controls. Immunohistochemistry was performed with polyclonal anti-human BMP-4 and monoclonal anti-human SMAD4 antibodies. All specimens of SCC and metastatic lymph nodes showed positive BMP-4 staining, which appeared weak and inconsistent for the control group.

BMP4 Administration Induces Differentiation of CD133+ Hepatic Cancer Stem Cells, Blocking Their Contributions to Hepatocellular Carcinoma

CD133+ cancer stem cells (CSC) contribute to hepatocellular carcinoma (HCC) progression and resistance to therapy. Bone morphogenetic protein BMP4 plays an important role in hepatogenesis and hepatic stem cell differentiation, but little is known about its function in hepatic CSCs. In this study, we showed that high-dose exogenous BMP4 promotes CD133+ HCC CSC differentiation and inhibits the self-renewal, chemotherapeutic resistance, and tumorigenic capacity of these cells. Interestingly, we found that low-dose exogenous BMP4 upregulated CD133 protein expression in vitro, and endogenous BMP4 was preferentially expressed in CD133+ HCC CSCs, suggesting that low doses of BMP4 may facilitate CSC maintenance. A reduction in endogenous BMP4 levels decreased CD133 protein expression in vitro. In HCC tissues, expression of the BMP4 signaling target gene SMAD6 was positively correlated with CD133 expression. Activation of the Erk1/2 signaling pathway led to BMP4-mediated reduction in CD133 expression, which was reversed by treatment with MEK inhibitors. Taken together, our findings indicated that BMP4 might be a potent therapeutic agent in HCC that targets CSCs.

BMP4 Promotes Prostate Tumor Growth in Bone through Osteogenesis

Induction of new bone formation is frequently seen in the bone lesions from prostate cancer. However, whether osteogenesis is necessary for prostate tumor growth in bone is unknown. Recently, 2 xenografts, MDA-PCa-118b and MDA-PCa-133, were generated from prostate cancer bone metastases. When implanted subcutaneously in severe combined immunodeficient (SCID) mice, MDA-PCa-118b induced strong ectopic bone formation while MDA-PCa-133 did not. To identify the factors that are involved in bone formation, we compared the expression of secreted factors (secretome) from MDA-PCa-118b and MDA-PCa-133 by cytokine array. We found that the osteogenic MDA-PCa-118b xenograft expressed higher levels of bone morphogenetic protein BMP4 and several cytokines including interleukin-8, growth-related protein (GRO), and CCL2. We showed that BMP4 secreted from MDA-PCa-118b contributed to about a third of the osteogenic differentiation seen in MDA-PCa-118b tumors. The conditioned media from MDA-PCa-118b induced a higher level of osteoblast differentiation, which was significantly reduced by treatment with BMP4 neutralizing antibody or the small molecule BMP receptor 1 inhibitor LDN-193189. BMP4 did not elicit an autocrine effect on MDA-PCa-118b, which expressed low to undetectable levels of BMP receptors. Treatment of SCID mice bearing MDA-PCa-118b tumors with LDN-193189 significantly reduced tumor growth. Thus, these studies support a role of BMP4-mediated osteogenesis in the progression of prostate cancer in bone.

DLX5 (Distal-less Homeobox 5) Promotes Tumor Cell Proliferation by Transcriptionally Regulating MYC

The human DLX homeobox genes, which are related to Dll (Drosophila distal-less gene), encode transcription factors that are expressed primarily in embryonic development. Recently, DLX5 was reported to act as an oncogene in lymphomas and lung cancers, although the mechanism is not known. The identification of target genes of DLX5 can facilitate our understanding of oncogenic mechanisms driven by overexpression of DLX5. The MYC oncogene is aberrantly expressed in many human cancers and regulates transcription of numerous target genes involved in tumorigenesis. Here we demonstrate by luciferase assay that the MYC promoter is specifically activated by overexpression of DLX5 and that two DLX5 binding sites in the MYC promoter are important for transcriptional activation of MYC. We also show that DLX5 binds to the MYC promoter both in vitro and in vivo and that transfection of a DLX5 expression plasmid promotes the expression of MYC in a dose-dependent manner in mammalian cells. Furthermore, overexpression of DLX5 results in increased cell proliferation by up-regulating MYC. Knockdown of DLX5 in lung cancer cells overexpressing DLX5 resulted in decreased expression of MYC and reduced cell proliferation, which was rescued by overexpression of MYC. Because DLX5 has a restricted pattern of expression in adult tissues, it may serve as a potential therapeutic target for the treatment of cancers that overexpress DLX5.

BMP-4 and BMP-6 involvement in the osteogenic properties of the HeLa cell line.

The heterotopically induced ossicles are used in our research on bone tissue. The ossicles are formed in the thigh muscle of BALB/c mice under the influence of injected suspension of 3 x 10(6) HeLa cells. We postulate that the mechanism of bone induction is based on the secretion of bone morphogenetic proteins BMP-4 and BMP-6 by the grafted HeLa cells. This was proved by the use of specific immunohistochemical reaction and Western blots of conditioned culture medium. It seems that HeLa cells secrete BMPs continuously into the culture medium, even without contact with the mice muscle tissue, were induction of bone tissue is observed.

Expression patterns of the bone morphogenetic protein genes Bmp-4 and Bmp-2 in the developing chick face suggest a role in outgrowth of the primordia.

Bone morphogenetic proteins BMP-4 and BMP-2 are closely-related members of the transforming growth factor-beta superfamily that have been implicated in signalling in a number of developmental systems. To determine whether they could be involved in the epithelial-mesenchymal interactions that control face development, we mapped the distribution of Bmp-4 and Bmp-2 gene transcripts in the developing chick facial primordia. At stages when primordia were becoming established, Bmp-4 transcripts were present in specific regions of epithelium in all facial primordia, but were undetectable in the mesenchyme. Bmp-4 transcripts appeared subsequently in specific regions of mesenchyme at the distal tips of the primordia. This mesenchymal expression first appeared in the frontonasal mass and then, in turn, in the lateral nasal processes, the maxillary primordia and the mandibular primordia. There was a complex relationship between domains of epithelial and mesenchymal Bmp-4 expression, and at many sites there was an inverse correlation between epithelial and mesenchymal Bmp-4 expression. Bmp-2 transcripts were found in the epithelium and mesenchyme of the maxillary and mandibular primordia at early stages in facial development. Bmp-2 transcripts appeared in the frontonasal mass and lateral nasal processes at later stages, with epithelial expression preceding mesenchymal expression. In general, mesenchymal Bmp-2 expression was associated with overlying epithelial Bmp-2 expression. The domains of Bmp-4 expression overlapped with those of Bmp-2, but detailed examination showed that there was no precise correlation between the expression patterns of the two genes. Indeed, in some places the Bmp-4 and Bmp-2 expression domains were complementary. The expression of the Bmp-4 and Bmp-2 genes in the epithelium and distal mesenchyme of the facial primordia suggests that BMP-4 and BMP-2 may be involved in the epithelial-mesenchymal interactions that control outgrowth of these primordia.