MB is supported by grant funding from an MRC fellowship. KP and AHM are supported by grant funding from Wessex Medical Research and Cancer Research UK/RCS (England) (C28503/A10013). We are thankful for the support of the University of Southampton Histochemistry Research Unit.

1. Establishment of Primary Fibroblast Cultures from Colonic Explants
<ol>
	<li>Obtain samples of normal human colon mucosa tissue directly from the surgical operating theatre, and suspend in 7-10 ml of PBS supplemented with 100 units/ml penicillin, 100 &#956;g/ml streptomycin, and 0.25 &#956;g/ml Fungizone.</li>
	<li>In the laboratory, place the specimen at the center of a 10-cm tissue culture dish and wash 3 times with PBS/Pen-strep/Fungizone. Do not aspirate after the final wash.</li>
	<li>With sterile forceps and s...

<ol>
	<li>Nystrom, M. L., Thomas, G. J., Stone, M., Mackenzie, I. C., Hart, I. R., Marshall, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+quantitative+method+to+analyse+tumour+cell+invasion+in+organotypic+culture.">Development of a quantitative method to analyse tumour cell invasion in organotypic culture.</a> J Pathol. 205 (4), 468-475 (2005).</li><li>Zhang, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=miR-153+supports+colorectal+cancer+progression+via+pleiotropic+effects+that+enhance+invasion+and+chemotherapeutic+resistance.">miR-153 supports colorectal cancer progression via pleiotropic effects that enhance invasion and chemotherapeutic resistance.</a> Cancer Res. , (2013).</li><li>Bullock, M. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pleiotropic+actions+of+miR-21+highlight+the+critical+role+of+deregulated+stromal+microRNAs+during+colorectal+cancer+progression.">Pleiotropic actions of miR-21 highlight the critical role of deregulated stromal microRNAs during colorectal cancer progression.</a> Cell Death Dis. 20 (4), (2013).</li><li>Jenei, V., Nystrom, M. L., Thomas, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+invasion+in+an+organotypic+model.">Measuring invasion in an organotypic model.</a> Methods Mol Biol. 769, 223-232 (2011).</li><li>De Wever, O., Demetter, P., Mareel, M., Bracke, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stromal+myofibroblasts+are+drivers+of+invasive+cancer+growth.">Stromal myofibroblasts are drivers of invasive cancer growth.</a> Int J Cancer. 123 (10), 2229-2238 (2008).</li><li>Fries, K. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+of+fibroblast+heterogeneity+and+the+role+of+fibroblast+subpopulations+in+fibrosis.">Evidence of fibroblast heterogeneity and the role of fibroblast subpopulations in fibrosis.</a> Clin Immunol Immunopathol. 72 (3), 283-292 (1994).</li><li>Moutasim, K. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Betel-derived+alkaloid+up-regulates+keratinocyte+alphavbeta6+integrin+expression+and+promotes+oral+submucous+fibrosis.">Betel-derived alkaloid up-regulates keratinocyte alphavbeta6 integrin expression and promotes oral submucous fibrosis.</a> J Pathol. 223 (3), 366-377 (2011).</li><li>Winter, J., Jung, S., Keller, S., Gregory, R. I., Diederichs, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Many+roads+to+maturity:+microRNA+biogenesis+pathways+and+their+regulation.">Many roads to maturity: microRNA biogenesis pathways and their regulation.</a> Nat Cell Biol. 11 (3), 228-234 (2009).</li><li>Li, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+miRNA+expression+patterns+using+total+RNA+extracted+from+matched+samples+of+formalin-fixed+paraffin-embedded+(FFPE)+cells+and+snap+frozen+cells.">Comparison of miRNA expression patterns using total RNA extracted from matched samples of formalin-fixed paraffin-embedded (FFPE) cells and snap frozen cells.</a> BMC Biotechnol. 7 (36), (2007).</li><li>Szafranska, A. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accurate+molecular+characterization+of+formalin-fixed,+paraffin-embedded+tissues+by+microRNA+expression+profiling.">Accurate molecular characterization of formalin-fixed, paraffin-embedded tissues by microRNA expression profiling.</a> J Mol Diagn. 10 (5), 415-423 (2008).</li></ol>

The authors disclose no potential conflicts of interest.

Here we describe a method to specifically isolate and characterize tumor cells which have acquired the capacity to invade the cancer associated stroma during the earliest stages of metastatic progression in a 3-dimensional co-culture construct of epithelial and stromal cells.
Co-culture models comprised of CRC epithelial cells juxtaposed with a synthetic stroma containing ex&#160;vivo human colonic fibroblasts were used to study CRC invasion in 3-dimensions. This physiologically relev...

Organotypic co-cultures are tissue-engineered models which aid in reconstructing the in vivo tumor microenvironment in 3-dimensions by juxtaposing malignant epithelial cells and stromal cells in a collagen gel containing essential extracellular matrix components1-3. Principally conceived as a method of measuring tumor invasion, organotypics reduce reliance on in vivo animal models, and avoid the shortcomings of other in vitro techniques such as Transwell assays, in which invading cells are forced artificially into a mono-dispersed state2-4. The inclusion of stromal cells in these models, such as fibroblasts, reflects the essential role of the tumor microenvironment in regulating malignant invasion and metastasis3-4, however the phenotypic heterogeneity of the stroma is such that in order to maximize the physiological relevance of organotypic models, organ specific, anatomically accurate ex vivo fibroblasts should be included wherever possible3,6.
Organotypics are a versatile platform to study interactions between tumor and stromal cells and are increasingly used in novel ways to examine the impact on tumor invasion of chemical inhibitors and targeted gene alterations7,8. Studying the invasive tumor margin is a particularly exciting prospect. In organotypic models, established colorectal cancer (CRC) cell lines typically produce a well stratified epithelial layer, and in cross section, cells that have acquired the capacity to invade the extracellular matrix (ECM) are easily discernible. In light of the established micro-topographic heterogeneity of tumor and tumor associated stromal cells in vivo, extracting these cells using Laser microdissection and studying them in isolation, may reveal important biological insights regarding the origins of colorectal cancer metastasis and how it may be more efficiently targeted. In the following methodology, all patients who donated tissue samples provided written informed consent, and the study was approved by the institutions regional research ethics committee.

<table border="0" cellpadding="0" cellspacing="0" width="634">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Colorectal cancer cell lines - example shown SW480</td>
			<td style="width:132px;">ATCC</td>
			<td style="width:119px;">ATCC CCL-228</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Collagen</td>
			<td style="width:132px;">BD Biosciences</td>
			<td style="width:119px;">354265</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Matrigel</td>
			<td style="width:132px;">BD Biosciences</td>
			<td style="width:119px;">354234</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Nylon membrane</td>
			<td style="width:132px;">Merck Millipore</td>
			<td style="width:119px;">VVLP01300</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Metal grid</td>
			<td style="width:132px;">The Mesh Company</td>
			<td>WSS20-A4</td>
			<td>themeshcompany.com</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Laser microdissection platform</td>
			<td style="width:132px;">Leica Microsystems</td>
			<td style="width:119px;">Leica AS LMD</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Membrane mounted slides</td>
			<td style="width:132px;">Molecular devices</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Cresyl Violet</td>
			<td style="width:132px;">Merck Millipore</td>
			<td style="width:119px;">1052350025</td>
			<td></td>
		</tr>
	</tbody>
</table>

molecular profiling of the invasive tumor microenvironment in a 3-dimensional model of colorectal cancer cells and ex vivo fibroblasts

Invading colorectal cancer (CRC) cells have acquired the capacity to break free from their sister cells, infiltrate the stroma, and remodel the extracellular matrix (ECM). Characterizing the biology of this phenotypically distinct group of cells could substantially improve our understanding of early events during the metastatic cascade.

Tumor invasion is a dynamic process facilitated by bidirectional interactions between malignant epithelium and the cancer associated stroma. In order to examine cell-specific responses at the tumor stroma-interface we have combined organotypic co-culture and laser micro-dissection techniques.
Organotypic models, in which key stromal constituents such as fibroblasts are 3-dimentioanally co-cultured with cancer epithelial cells, are highly manipulatable experimental tools which enable invasion and cancer-stroma interactions to be studied in near-physiological conditions.

Laser microdissection (LMD) is a technique which entails the surgical dissection and extraction of the various strata within tumor tissue, with micron level precision.
By combining these techniques with genomic, transcriptomic and epigenetic profiling we aim to develop a deeper understanding of the molecular characteristics of invading tumor cells and surrounding stromal tissue, and in doing so potentially reveal novel biomarkers and opportunities for drug development in CRC.&#160;&#160;&#160;

We have applied the above method to multiple combinations of CRC cell lines and stromal cells. One example presented here is SW480 epithelial CRC cell lines with primary human ex&#160;vivo colonic fibroblasts. 3-dimensional co-cultures are constructed (Figure 1), subjected to microscopy and laser capture microdissection (Figure 2), and analyzed by microRNA (miRNA) profiling (Figure 3) for comparison of differentially expressed miRNAs between cells at the invasiv...

Watch this Scientific Journal Video about Molecular Profiling of the Invasive Tumor Microenvironment in a 3-Dimensional Model of Colorectal Cancer Cells and Ex vivo Fibroblasts at JoVE.com

Molecular Profiling of the Invasive Tumor Microenvironment in a 3-Dimensional Model of Colorectal Cancer Cells and Ex vivo Fibroblasts

Molecular profiling of laser microdissected cells and stroma from synthetic, tissue-engineered colorectal cancer models represents a novel and manipulatable approach to characterize and dissect the distinctive biology at the interface between tumor cells at the invasive front and cancer associated stromal cells. &#160;

Molecular Profiling of the Invasive Tumor Microenvironment in a 3-Dimensional Model of Colorectal Cancer Cells and Ex vivo Fibroblasts

Invading colorectal cancer (CRC) cells have acquired the capacity to break free from their sister cells, infiltrate the stroma, and remodel the ...

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11.0K Views.  University of Southampton School of Medicine. Molecular profiling of laser microdissected cells and stroma from synthetic, tissue-engineered colorectal cancer models represents a novel and manipulatable approach to characterize and dissect the distinctive biology at the interface between tumor cells at the invasive front and cancer associated stromal cells.  