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The epigenetic influence of tumor and embryonic microenvironments: how different are they?

Abbott DE, Bailey CM, Postovit LM, Seftor EA, Margaryan N, Seftor RE, Hendrix MJ - Cancer Microenviron (2008)

Bottom Line: The microenvironment is being increasingly recognized as a critical component in tumor progression and metastases.As such, the bi-directional signaling of extracellular mediators that promote tumor growth within the microenvironment is a focus of intense scrutiny.Moreover, we have a better appreciation of the convergence of embryonic and tumorigenic signaling pathways that might stimulate further consideration of targeting Nodal in aggressive tumor cells resulting in a down-regulation of tumorigenic potential and plasticity.

View Article: PubMed Central - PubMed

Affiliation: Children's Memorial Research Center, Department of Surgery, Northwestern University/Feinberg School of Medicine, Chicago, IL 60614, USA.

ABSTRACT
The microenvironment is being increasingly recognized as a critical component in tumor progression and metastases. As such, the bi-directional signaling of extracellular mediators that promote tumor growth within the microenvironment is a focus of intense scrutiny. Interestingly, there are striking similarities between the phenotypes of aggressive tumor and embryonic stem cells, particularly with respect to specific signaling pathways underlying their intriguing plasticity. Here, we demonstrate the epigenetic influence of the hESC microenvironment on the reprogramming of aggressive melanoma cells using an innovative 3-D model. Specifically, our laboratory has previously demonstrated the redifferentiation of these melanoma cells to a more melanocyte-like phenotype (Postovit et al., Stem Cells 24(3):501-505, 2006), and now we show the loss of VE-Cadherin expression (indicative of a plastic vasculogenic phenotype) and the loss of Nodal expression (a plasticity stem cell marker) in tumor cells exposed to the hESC microenvironment. Further studies with the 3-D culture model revealed the epigenetic influence of aggressive melanoma cells on hESCs resulting in the down-regulation of plasticity markers and the emergence of phenotype-specific genes. Additional studies with the aggressive melanoma conditioned matrix microenvironment demonstrated the transdifferentiation of normal melanocytes into melanoma-like cells exhibiting a vasculogenic phenotype. Collectively, these studies have advanced our understanding of the epigenetic influence associated with the microenvironments of hESCs and aggressive melanoma cells, and shed new light on their therapeutic implications. Moreover, we have a better appreciation of the convergence of embryonic and tumorigenic signaling pathways that might stimulate further consideration of targeting Nodal in aggressive tumor cells resulting in a down-regulation of tumorigenic potential and plasticity.

No MeSH data available.


Related in: MedlinePlus

hESCs exhibit a vasculogenic and mesenchymal-like phenotype following exposure to the microenvironment of metastatic melanoma cells. a Phase-contrast microscopy of hESCs grown on 3-D Matrigel matrices. Under control conditions, hESCs grow as densely packed undifferentiated colonies. In contrast, hESCs cultured on a matrix conditioned by C8161 cells (C8161 CMTX) exhibit an altered phenotype reminiscent of cell differentiation. b Real time RT-PCR analysis of Nodal, Lefty, Nanog, Vimentin, and VE-Cadherin mRNA in hESCs exposed for 3 days to either control (unconditioned) Matrigel or to Matrigel conditioned by human metastatic melanoma cells (C8161 CMTX). Gene levels were normalized using RPLPO and bars represent mean gene expression±standard deviation normalized to gene expression in hESCs cultured under control conditions
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Fig4: hESCs exhibit a vasculogenic and mesenchymal-like phenotype following exposure to the microenvironment of metastatic melanoma cells. a Phase-contrast microscopy of hESCs grown on 3-D Matrigel matrices. Under control conditions, hESCs grow as densely packed undifferentiated colonies. In contrast, hESCs cultured on a matrix conditioned by C8161 cells (C8161 CMTX) exhibit an altered phenotype reminiscent of cell differentiation. b Real time RT-PCR analysis of Nodal, Lefty, Nanog, Vimentin, and VE-Cadherin mRNA in hESCs exposed for 3 days to either control (unconditioned) Matrigel or to Matrigel conditioned by human metastatic melanoma cells (C8161 CMTX). Gene levels were normalized using RPLPO and bars represent mean gene expression±standard deviation normalized to gene expression in hESCs cultured under control conditions

Mentions: Melanocytes are not the only cell type susceptible to this kind of epigenetic modulation by a cancerous microenvironment. When hESCs are cultured on a 3-D matrix conditioned by aggressive melanoma cells for 3 days, their morphologic transformation is striking (Fig. 4a). Rather than typical spheroidal clusters under control conditions (top left panel), hESCs begin to flatten on the matrix, migrate as a monolayer, and exhibit a mesenchymal-like morphology—characteristics associated with the aggressive melanoma cells that conditioned this microenvironment. This dramatic change in cell morphology is associated with intriguing gene expression changes as well (Fig. 4b). hESCs cultured on an C8161 CMTX for 3 days and harvested for mRNA analysis demonstrate: (1) a significant down-regulation of markers associated with embryonic stem cell pluripotency and an undifferentiated state (Nodal, Lefty and Nanog), and (2) dramatic amplification of genes associated with a differentiated cellular phenotype (Vimentin and VE-Cadherin). Specifically, Nodal is suppressed to nearly 20% of control levels, consistent with the morphologic changes noted in Fig. 4a following exposure to an C8161 CMTX. Lefty, one of Nodal’s inhibitors and expressed primarily by undifferentiated hESCs, is found at less than 50% of control levels. Again, this finding is consistent with the notion that hESCs, induced by the cancerous microenvironment, lose this regulatory factor inherent to hESCs—and critical to cell fate determination. Furthermore, Nanog, a marker widely associated with ‘stemness’, is decreased in expression following hESC exposure to a melanoma tumor-conditioned microenvironment.Fig. 4


The epigenetic influence of tumor and embryonic microenvironments: how different are they?

Abbott DE, Bailey CM, Postovit LM, Seftor EA, Margaryan N, Seftor RE, Hendrix MJ - Cancer Microenviron (2008)

hESCs exhibit a vasculogenic and mesenchymal-like phenotype following exposure to the microenvironment of metastatic melanoma cells. a Phase-contrast microscopy of hESCs grown on 3-D Matrigel matrices. Under control conditions, hESCs grow as densely packed undifferentiated colonies. In contrast, hESCs cultured on a matrix conditioned by C8161 cells (C8161 CMTX) exhibit an altered phenotype reminiscent of cell differentiation. b Real time RT-PCR analysis of Nodal, Lefty, Nanog, Vimentin, and VE-Cadherin mRNA in hESCs exposed for 3 days to either control (unconditioned) Matrigel or to Matrigel conditioned by human metastatic melanoma cells (C8161 CMTX). Gene levels were normalized using RPLPO and bars represent mean gene expression±standard deviation normalized to gene expression in hESCs cultured under control conditions
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2654360&req=5

Fig4: hESCs exhibit a vasculogenic and mesenchymal-like phenotype following exposure to the microenvironment of metastatic melanoma cells. a Phase-contrast microscopy of hESCs grown on 3-D Matrigel matrices. Under control conditions, hESCs grow as densely packed undifferentiated colonies. In contrast, hESCs cultured on a matrix conditioned by C8161 cells (C8161 CMTX) exhibit an altered phenotype reminiscent of cell differentiation. b Real time RT-PCR analysis of Nodal, Lefty, Nanog, Vimentin, and VE-Cadherin mRNA in hESCs exposed for 3 days to either control (unconditioned) Matrigel or to Matrigel conditioned by human metastatic melanoma cells (C8161 CMTX). Gene levels were normalized using RPLPO and bars represent mean gene expression±standard deviation normalized to gene expression in hESCs cultured under control conditions
Mentions: Melanocytes are not the only cell type susceptible to this kind of epigenetic modulation by a cancerous microenvironment. When hESCs are cultured on a 3-D matrix conditioned by aggressive melanoma cells for 3 days, their morphologic transformation is striking (Fig. 4a). Rather than typical spheroidal clusters under control conditions (top left panel), hESCs begin to flatten on the matrix, migrate as a monolayer, and exhibit a mesenchymal-like morphology—characteristics associated with the aggressive melanoma cells that conditioned this microenvironment. This dramatic change in cell morphology is associated with intriguing gene expression changes as well (Fig. 4b). hESCs cultured on an C8161 CMTX for 3 days and harvested for mRNA analysis demonstrate: (1) a significant down-regulation of markers associated with embryonic stem cell pluripotency and an undifferentiated state (Nodal, Lefty and Nanog), and (2) dramatic amplification of genes associated with a differentiated cellular phenotype (Vimentin and VE-Cadherin). Specifically, Nodal is suppressed to nearly 20% of control levels, consistent with the morphologic changes noted in Fig. 4a following exposure to an C8161 CMTX. Lefty, one of Nodal’s inhibitors and expressed primarily by undifferentiated hESCs, is found at less than 50% of control levels. Again, this finding is consistent with the notion that hESCs, induced by the cancerous microenvironment, lose this regulatory factor inherent to hESCs—and critical to cell fate determination. Furthermore, Nanog, a marker widely associated with ‘stemness’, is decreased in expression following hESC exposure to a melanoma tumor-conditioned microenvironment.Fig. 4

Bottom Line: The microenvironment is being increasingly recognized as a critical component in tumor progression and metastases.As such, the bi-directional signaling of extracellular mediators that promote tumor growth within the microenvironment is a focus of intense scrutiny.Moreover, we have a better appreciation of the convergence of embryonic and tumorigenic signaling pathways that might stimulate further consideration of targeting Nodal in aggressive tumor cells resulting in a down-regulation of tumorigenic potential and plasticity.

View Article: PubMed Central - PubMed

Affiliation: Children's Memorial Research Center, Department of Surgery, Northwestern University/Feinberg School of Medicine, Chicago, IL 60614, USA.

ABSTRACT
The microenvironment is being increasingly recognized as a critical component in tumor progression and metastases. As such, the bi-directional signaling of extracellular mediators that promote tumor growth within the microenvironment is a focus of intense scrutiny. Interestingly, there are striking similarities between the phenotypes of aggressive tumor and embryonic stem cells, particularly with respect to specific signaling pathways underlying their intriguing plasticity. Here, we demonstrate the epigenetic influence of the hESC microenvironment on the reprogramming of aggressive melanoma cells using an innovative 3-D model. Specifically, our laboratory has previously demonstrated the redifferentiation of these melanoma cells to a more melanocyte-like phenotype (Postovit et al., Stem Cells 24(3):501-505, 2006), and now we show the loss of VE-Cadherin expression (indicative of a plastic vasculogenic phenotype) and the loss of Nodal expression (a plasticity stem cell marker) in tumor cells exposed to the hESC microenvironment. Further studies with the 3-D culture model revealed the epigenetic influence of aggressive melanoma cells on hESCs resulting in the down-regulation of plasticity markers and the emergence of phenotype-specific genes. Additional studies with the aggressive melanoma conditioned matrix microenvironment demonstrated the transdifferentiation of normal melanocytes into melanoma-like cells exhibiting a vasculogenic phenotype. Collectively, these studies have advanced our understanding of the epigenetic influence associated with the microenvironments of hESCs and aggressive melanoma cells, and shed new light on their therapeutic implications. Moreover, we have a better appreciation of the convergence of embryonic and tumorigenic signaling pathways that might stimulate further consideration of targeting Nodal in aggressive tumor cells resulting in a down-regulation of tumorigenic potential and plasticity.

No MeSH data available.


Related in: MedlinePlus