We greatly appreciate the editorial contributions by Cheryl Schaeberle. This research was supported by Avon Grants #02-2009-093 and 02-2011-095, and NIEHS/NIH ES 08314 to AMS. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Environmental Health Sciences or the National Institutes of Health.

1. Preparation of Reagents
<ol>
	<li>Dissolve the synthetic progestagen promegestone (R5020) and 17-&#946;-estradiol (E2) in ethanol to make 10-3 M stock solutions. Dissolve prolactin in distilled deionized water to make a 1 mg/ml stock solution. Dissolve the antiestrogen ICI 182,780 in DMSO to make a 10-2M stock solution. Store these solutions at -20 &#176; C for up to 6 months.</li>
	<li>Charcoal dextran (CD) stripped serum and CDFBS medium:
	<ol>
		<li>Heat-inactivate fetal bovine serum (FBS) in a 57 &#176;C water bath for 30 min. 
		Note: Use only acid-washed glassware for the remainder of this protocol.</li>
		<li>Calculate the amount of charcoal needed. Using 10% more volume than the amount of serum to compensate for the displacement caused by the charcoal, weigh 5% wt/vol activated powdered charcoal.</li>
		<li>Wash charcoal twice with cold deionized distilled water using the same volume as the amount of serum. For each wash centrifuge at 50 x g for 2 min to pellet the charcoal. Remove the water between washes. Add 0.5% wt/vol Dextran T-70 to the last charcoal pellet. Re-suspend with distilled, deionized water and centrifuge at 100 x g for 5 min. Aspirate the water.</li>
		<li>Add the appropriate volume of serum to the pellet and re-suspend the charcoal dextran pellet into the serum. Incubate, while rolling (6 RPM), at 37 &#186;C for 60 min. Centrifuge at 2,000 x g for 20 min. If supernatant appears cloudy, repeat centrifugation; however, serum may not be completely clear at this time but will be cleared during filtration.</li>
		<li>Filter through a 0.80 micron filter and then again through a 0.45 micron filter to remove larger particulate matter. Finally, filter-sterilize with a 0.20 micron filter. Store filtered CDFBS in glass tubes or T-25 culture flasks at -20 &#186;C.</li>
		<li>Charcoal Dextran Stripped Fetal Bovine-containing media (CDFBS media): mix 375 ml of phenol red-free DMEM and 125 ml of DMEM/F-12. Remove 37.5 ml and replace it with the same volume of Charcoal Dextran Stripped Fetal Bovine serum. Add 106 U/ml penicillin and L-glutamine to a 2 mM final concentration. The resulting media is 75% DMEM, 25% DMEM/F-12, 7.5% Charcoal dextran stripped-FBS, 2mM L-glutamine, and 106 U/ml penicillin.</li>
	</ol>
	</li>
	<li>Prepare 10X PBS, 1N NaOH and distilled deionized water. Prepare enough volume of each according to the volume of collagen solution needed. Sterilize all solutions by filtering. Store the 10x PBS and sterile distilled deionized water at 4 &#176; C for up to 1 month. Do not store the 1N NaOH solution.</li>
	<li>Prepare collagen solution at a 1 mg/ml final concentration according to the protocol for &#34;Alternate Gelation Procedure for Collagen I, Rat tail&#34; provided by the manufacturer. Each gel is made of 1.5 ml of collagen solution. For example, prepare 18.5 ml (0.5 ml to account for loss during pipetting) of collagen solution to prepare 12 gels. Use the collagen solution immediately or hold on ice for up to 2-3 hr.</li>
	<li>Carmine Alum dye:
	<ol>
		<li>Combine 1 g Carmine and 2.5 g Aluminum potassium sulfate in 500 ml distilled water. Boil while stirring for 20 min. Watch carefully to avoid boiling over. Adjust final volume back to 500 ml with additional distilled water.</li>
		<li>Add a crystal of thymol for antimicrobial activity and cover bottle with aluminum foil to protect from light. Filter through a laboratory grade paper filter before each use. Reuse the carmine solution for up to three months. Store at RT, protected from light.</li>
	</ol>
	</li>
	<li>Collagenase solution: dissolve the collagenase in DMEM/F12 medium at a concentration of 0.125% w/v. Do not store this solution.</li>
</ol>
2. 3D Culture of T47D Cells in Rat Tail Collagen Type 1 Gels and Hormone Treatment
Note: keep sterile serological pipettes and pipette tips at 4 &#176;C.
<ol>
	<li>Prepare a single-cell suspension and perform a cell count. Split T47D cell cultures before they reach 70% confluence. Centrifuge the volume that contains the amount of cells needed. Consider that one gel should contain about 75,000 T47D cells.</li>
	<li>Using a cold-pipette, re-suspend the cell pellet in the appropriate volume of collagen. Consider that each gel is made up of 1.5 ml of collagen. Mix the cells and the collagen gently to avoid introducing bubbles.</li>
	<li>To prevent the effect of static electricity on cell distribution, brush the borders, top and bottom of the 12-well plate with a static-reducing brush after unwrapping the plate. To avoid static charge buildup during contact with the working surface of the hood, place this plate on top of another 12-well plate (blank plate) that has also been brushed with the static-reducing brush.Gently, pour 1.5 ml of the mix into each well of the 12-well plate.</li>
	<li>Place the plate in an incubator at 37 &#176;C for 30 min. Remove the plate from the incubator and place it back in the hood.</li>
	<li>Using a p200 sterile tip, carefully detach the gel in a gentle circular motion from the border of the well. The gel should also detach from the bottom of the well.</li>
	<li>Dilute hormones in CDFBS media to be added to the wells. Use E2 and R5020 at a 10 -10 M final concentration and prolactin at a at 10-7 M final concentration. As control, use CDFBS media without hormones added but still containing the highest volume of DMSO equal to the hormone stocks used. Ensure that each well contains 1.5 ml of media. Place the 3D cultures inside a 37 &#176;C, 5% CO2, 100% humidity tissue culture incubator. Maintain the cultures for 1 or 2 weeks, changing the media every 2 days.</li>
</ol>
3. Gel Processing for Whole Mounts
<ol>
	<li>Remove culture media and add 1.5 ml of PBS to each well.</li>
	<li>Transfer the gel to a slide. Cut the gel in half using a curved surgical blade. Continue processing with one half and save the other half for histological analysis.</li>
	<li>Transfer the half gel for whole mount to a slide. Let gel dry for 5 min and then transfer the slide to a coplin jar containing 10% formalin. 
	Note: all incubations should be done at RT.</li>
	<li>Fix gels in a coplin jar on a shaker O/N.</li>
	<li>Wash slides twice with PBS for 10 min each on shaker. Transfer slides to 70% EtOH; incubate for 1 hr on shaker. Transfer slides to Carmine Alum O/N.</li>
	<li>The next day, dehydrate slides on shaker in 70% EtOH, 95% EtOH and 100% EtOH for 1 hr each. Transfer slides to xylene twice for 1 hr each and keep on shaker. Use toluene-based mounting medium to mount the gels and 1.5 mm thick coverslips.</li>
	<li>Examine whole mounts under regular light (microscope or stereoscope). For a more detailed analysis of shape and lumen use confocal microscopy and visualize Carmine dye with HeNE 633 nm laser.</li>
</ol>
4. Gel Processing for Processing for Histology Analysis
<ol>
	<li>Transfer the remaining half of the gel to a 20 ml glass vial containing 10% formalin and fix on shaker O/N.</li>
	<li>Wash gels twice with PBS for 10 min each on shaker. Place gels into processing cassettes for paraffin embedding.</li>
	<li>Transfer gels to 70% EtOH, incubate for 1 hr and follow with 95% EtOH for 1 hr, change to fresh 95% EtOH for 1 hr, 100% EtOH for 1 hr, and change to fresh 100% EtOH for 1 hr. At this point, gels may be stored in 100% EtOH O/N at RT or incubated with xylene for 1 hr and then again in fresh xylene for 1 hr.</li>
	<li>Transfer cassettes to paraffin for 1 hr at 60 &#176;C in vacuum incubator, repeat with fresh paraffin twice more.</li>
	<li>Fill plastic molds with clean paraffin. Open the cassette, remove the gel and place it in the plastic mold containing paraffin. Fill up with paraffin and add top of cassette containing the label on top and let block cool.</li>
	<li>Remove the plastic mold and section the block using a microtome. Obtain 5 um thick sections for H-E staining and immunocytochemistry.</li>
</ol>
5. Extraction of Cells from Cells from Gels Using Collagenase Treatment
<ol>
	<li>Remove gel from the well and transfer it to a petri dish containing PBS. Rinse gel briefly.</li>
	<li>Transfer the gel to a 15 ml tube containing 2 ml of 0.125% collagenase. Pipette up and down 4-5 times in order to break the gel into small pieces.</li>
	<li>Incubate at 37 &#176;C for 25 min (until gel has dissolved and cells are in suspension)</li>
	<li>Add 2 ml of serum supplemented culture medium. Collect cells by centrifugation (1,000 x g, 5 min), discard supernatant, re-suspend cells and count.</li>
</ol>

<ol>
	<li>Barnes, C., 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=From+single+cells+to+tissues:+interactions+between+the+matrix+and+human+breast+cells+in+real+time.">From single cells to tissues: interactions between the matrix and human breast cells in real time.</a> PLoS ONE. 9, e93325 (2014).</li><li>Berthois, Y., Katzenellenbogen, J. A., Katzenellenbogen, B. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phenol+red+in+tissue+culture+is+a+weak+estrogen:+implications+concerning+the+study+of+estrogen+responsive+cells+in+culture.">Phenol red in tissue culture is a weak estrogen: implications concerning the study of estrogen responsive cells in culture.</a> Proc.Nat.Acad.Sci.USA. 83, 2496-2500 (1986).</li><li>Chalbos, D., Vignon, F., Keydar, I., Rochefort, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estrogens+stimulate+cell+proliferation+and+induce+secretory+proteins+in+a+human+breast+cancer+cell+line+(T47D).">Estrogens stimulate cell proliferation and induce secretory proteins in a human breast cancer cell line (T47D).</a> J.Clin.Endocrinol.Metab. 55, 276-283 (1982).</li><li>Dhimolea, E., Maffini, M. V., Soto, A. M., Sonnenschein, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+collagen+reorganization+on+mammary+epithelial+morphogenesis+in+a+3D+culture+model.">The role of collagen reorganization on mammary epithelial morphogenesis in a 3D culture model.</a> Biomaterials. 31, 3622-3630 (2010).</li><li>Dhimolea, E., Soto, A. M., Sonnenschein, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Breast+epithelial+tissue+morphology+is+affected+in+3D+cultures+by+species-specific+collagen-based+extracellular+matrix.">Breast epithelial tissue morphology is affected in 3D cultures by species-specific collagen-based extracellular matrix.</a> J.Biomed.Mat.Res.A. 100, 2905-2912 (2012).</li><li>Krause, S., 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=Dual+regulation+of+breast+tubulogenesis+using+extracellular+matrix+composition+and+stromal+cells.">Dual regulation of breast tubulogenesis using extracellular matrix composition and stromal cells.</a> Tissue Eng Part A. 18, 520-532 (2012).</li><li>Krause, S., Maffini, M. V., Soto, A. M., Sonnenschein, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+3D+in+vitro.+culture+model+to+study+stromal-epithelial+interactions+in+the+mammary+gland.">A novel 3D in vitro. culture model to study stromal-epithelial interactions in the mammary gland.</a> Tissue Eng.Part C Methods. 14, 261-271 (2008).</li><li>Krause, S., Maffini, M. V., Soto, A. M., Sonnenschein, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+microenvironment+determines+the+breast+cancer+cells'+phenotype:+organization+of+MCF7+cells+in+3D+cultures.">The microenvironment determines the breast cancer cells' phenotype: organization of MCF7 cells in 3D cultures.</a> BMC Cancer. 10, 263-275 (2010).</li><li>Lee, G. Y., Kenny, P. A., Lee, E. H., Bissell, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+culture+models+of+normal+and+malignant+breast+epithelial+cells.">Three-dimensional culture models of normal and malignant breast epithelial cells.</a> Nat.Methods. 4, 359-365 (2007).</li><li>Martinson, H. A., Jindal, S., Durand-Rougely, C., Borges, V. F., Schedin, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wound+healing-like+immune+program+facilitates+postpartum+mammary+gland+involution+and+tumor+progression.">Wound healing-like immune program facilitates postpartum mammary gland involution and tumor progression.</a> Int.J.Cancer. , (2014).</li><li>Soto, A. M., Murai, J. T., Siiteri, P. K., Sonnenschein, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+cell+proliferation:+evidence+for+negative+control+on+estrogen-sensitive+T47D+human+breast+cancer+cells.">Control of cell proliferation: evidence for negative control on estrogen-sensitive T47D human breast cancer cells.</a> Cancer Res. 46, 2271-2275 (1986).</li><li>Speroni, 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=Hormonal+regulation+of+epithelial+organization+in+a+3D+breast+tissue+culture+model.">Hormonal regulation of epithelial organization in a 3D breast tissue culture model.</a> Tissue Eng.Part C Methods. 20, 42-51 (2014).</li><li>Vignon, F., Bardon, S., Chalbos, D., Rochefort, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antiestrogenic+effect+of+R5020,+a+synthetic+progestin+in+human+breast+cancer+cells+in+culture.">Antiestrogenic effect of R5020, a synthetic progestin in human breast cancer cells in culture.</a> J.Clin.Endocrinol.Metab. 56, 1124-1130 (1983).</li></ol>

The authors have nothing to disclose.

Here, we describe a hormone-sensitive 3D culture model to test the action of hormones on breast epithelium. The response to hormones can be assessed at the tissue morphology, cell proliferation and gene expression levels 12. One limitation of this technique is that visualization during the culture period is restricted to light microscopy since the cultures are grown in a plastic bottom plate. The 3D culture system could be adapted to glass bottom plates to allow for live imaging of the cultures 1.</...

Unlike standard 2D cultures, 3D cell culture surrogate models allow for the study of epithelial cell behavior in a physiologically relevant context, one resembling a tissue. 3D cultures of the mammary gland have helped elucidate many aspects of mammary gland development and neoplasia. However, most of the 3D culture models currently available are unsuitable to study hormone action because the human epithelial cell lines used for the task lack hormone receptor expression 6,7,9.
Herein, we describe a 3D culture model of the human breast epithelium that is suitable to study hormone action 12. This model uses the commercially available hormone-responsive human breast epithelial cell line, T47D 3,11,13, which were originally derived from a pleural effusion obtained from a 54 year old female patient with an infiltrating ductal carcinoma of the breast. We use rat tail collagen type 1 as a matrix. This 3D culture model is appropriate for the study of the action of the three main mammotropic hormones (estradiol, promegestone (an analogue of progesterone), and prolactin) on human breast epithelial cells. Hormone-induced epithelial morphology can be assessed quantitatively over time by morphometric analysis12.
An appropriate seeding density allows these 3D cultures to be kept for 2 weeks. By this time, the development of structures is sufficient for a robust quantitative assessment of hormone action on epithelial morphology. Gels may also be harvested at earlier time points for cell proliferation and gene expression analyses. Additionally, this model is suitable to test the effects of a sequential hormonal treatment; for example, after treatment with estradiol during the first week and replacement with other hormone/combination of hormones during the following week. The effect of estrogenic compounds and antiestrogens, such as ICI 182,780, can also be studied using this 3D culture model 12.

<table border="0" cellpadding="0" cellspacing="0" width="1344">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">12-well Tissue Culture Plates (Falcon)</td>
			<td style="width:249px;">Fisher Scientific</td>
			<td style="width:171px;">08-772-29</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">15 ml polystyrene conical Tubes</td>
			<td style="width:249px;">Fisher Scientific</td>
			<td style="width:171px;">14-959-49D</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Activated Charcoal</td>
			<td style="width:249px;">Sigma</td>
			<td style="width:171px;">C-5510</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Carmine Alum</td>
			<td style="width:249px;">Sigma</td>
			<td style="width:171px;">C1022-100G</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Collagenase, Type 3</td>
			<td style="width:249px;">Worthington</td>
			<td style="width:171px;">S0C11784</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Confocal Microscope</td>
			<td style="width:249px;">Zeiss</td>
			<td style="width:171px;">LSM510</td>
			<td style="width:488px;">Equiped with HeNe 633nm laser</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Dextran T-70</td>
			<td style="width:249px;">Abersham/Pharmacia</td>
			<td style="width:171px;">17-0280-01</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">DMEM/F-12, HEPES, no phenol red&#160;</td>
			<td style="width:249px;">Life Technologies</td>
			<td style="width:171px;">11339-021</td>
			<td style="width:488px;">Phenol red-free media for hormone use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:22px;width:436px;">DMEM, low glucose, pyruvate, no glutamine, no phenol red</td>
			<td style="width:249px;">Life Technologies</td>
			<td style="width:171px;">11054-020</td>
			<td style="width:488px;">Phenol red-free media for hormone use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">17-&#946;-Estradiol</td>
			<td style="width:249px;">EMD Millipore</td>
			<td style="width:171px;">3301</td>
			<td style="width:488px;">Dissolved in Ethanol</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Ethanol</td>
			<td style="width:249px;">Koptec</td>
			<td style="width:171px;">V1001</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Fetal Bovine Serum</td>
			<td style="width:249px;">Hyclone</td>
			<td style="width:171px;">SH30070.03</td>
			<td style="width:488px;">For use with hormones, must be Charcoal Dextran stripped&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:436px;">Filters (115ml)</td>
			<td style="width:249px;">Nalgene</td>
			<td style="width:171px;">380-0080, 245-0045, 120-0020</td>
			<td style="width:488px;">0.88, 0.45, 0.20 micron, respectively&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Formalin, 10%</td>
			<td style="width:249px;">Fisher Scientific</td>
			<td style="width:171px;">SF93-20</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">L-Glutamine (200 mM)</td>
			<td style="width:249px;">Life Technologies</td>
			<td style="width:171px;">25030-081</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">ICI 182,780 (fulvestrant)</td>
			<td style="width:249px;">Sigma Aldrich</td>
			<td style="width:171px;">I4409-25MG</td>
			<td style="width:488px;">Dissolved in DMSO</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Microtome&#160;</td>
			<td style="width:249px;">Leica</td>
			<td style="width:171px;">RM2155</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Tissue embedding media</td>
			<td style="width:249px;">McCormick Scientific</td>
			<td style="width:171px;">39502004</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Penicillin</td>
			<td style="width:249px;">Sigma</td>
			<td style="width:171px;">7794-10MU</td>
			<td style="width:488px;">Dissolved in 10 ml of distilled deionized water</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Permount</td>
			<td style="width:249px;">Fisher Scientific</td>
			<td style="width:171px;">SP15-500</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Phosphate Buffered Saline pH 7.4</td>
			<td style="width:249px;">Sigma Aldrich</td>
			<td style="width:171px;">P3813-10PAK</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Prolactin</td>
			<td style="width:249px;">Sigma Aldrich</td>
			<td style="width:171px;">L4021-50UG</td>
			<td style="width:488px;">Dissolved in distilled deionized water</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Promegestone</td>
			<td style="width:249px;">Perkin Elmer</td>
			<td style="width:171px;">NLP004005MG</td>
			<td style="width:488px;">Dissolved in Ethanol</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Rat-Tail Collagen&#160;</td>
			<td style="width:249px;">Corning&#160;</td>
			<td style="width:171px;">354236</td>
			<td style="width:488px;">Lots may contain varying concentrations, note accordingly</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Scalpel</td>
			<td style="width:249px;">Miltex</td>
			<td style="width:171px;">4311</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Semi-enclosed Benchtop Tissue Processor</td>
			<td style="width:249px;">Leica</td>
			<td style="width:171px;">TP1020</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Sodium Hydroxide</td>
			<td style="width:249px;">Sigma Aldrich</td>
			<td style="width:171px;">S5881</td>
			<td style="width:488px;">Prepare 1N NaOH stock</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">StaticMaster Anti-static brush&#160;</td>
			<td style="width:249px;">Amstat</td>
			<td style="width:171px;">C3500</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Stripette Serological Pipettes&#160;</td>
			<td style="width:249px;">Corning&#160;</td>
			<td style="width:171px;">4101</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">T-25 flasks</td>
			<td style="width:249px;">Corning&#160;</td>
			<td style="width:171px;">430168</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Tissue Cassettes</td>
			<td style="width:249px;">Fisher Scientific</td>
			<td style="width:171px;">15-200-403E</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Wheaton Vials, Glass, 20mL</td>
			<td style="width:249px;">Fisher Scientific</td>
			<td style="width:171px;">03-341-25D&#160;</td>
			<td style="width:488px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:436px;">Xylene&#160;</td>
			<td style="width:249px;">VWR</td>
			<td style="width:171px;">95057-822</td>
			<td style="width:488px;"></td>
		</tr>
	</tbody>
</table>

a hormone-responsive 3d culture model of the human mammary gland epithelium

The process of mammary epithelial morphogenesis is influenced by hormones. The study of hormone action on the breast epithelium using 2D cultures is limited to cell proliferation and gene expression endpoints. However, in the organism, mammary morphogenesis occurs in a 3D environment. 3D culture systems help bridge the gap between monolayer cell culture (2D) and the complexity of the organism. Herein, we describe a 3D culture model of the human breast epithelium that is suitable to study hormone action. It uses the commercially available hormone-responsive human breast epithelial cell line, T47D, and rat tail collagen type 1 as a matrix. This 3D culture model responds to the main mammotropic hormones: estradiol, progestins and prolactin. The influence of these hormones on epithelial morphogenesis can be observed after 1- or 2-week treatment according to the endpoint. The 3D cultures can be harvested for analysis of epithelial morphogenesis, cell proliferation and gene expression.

Figure 1 summarizes the procedure for preparing the hormone-sensitive 3D cultures. Epithelial structures are observed in whole mounts of gels cultured for 2 weeks in the presence of E2 alone and in combination with other hormones. Only single cells or groups of 2-3 cells are present when no hormones are added to the culture medium (CDFBS medium) (Figure 2). This condition serves as a negative control.
Cells in 3D culture form structures that vary in shape, siz...

Watch this Scientific Journal Video about A Hormone-responsive 3D Culture Model of the Human Mammary Gland Epithelium at JoVE.com

A Hormone-responsive 3D Culture Model of the Human Mammary Gland Epithelium

We describe a 3D culture model of the human breast epithelium that is suitable to study hormone action.

The process of mammary epithelial morphogenesis is influenced by hormones. The study of hormone action on the breast epithelium using 2D cultures is ...

a-hormone-responsive-3d-culture-model-human-mammary-gland

Research

JoVE Journal

Bioengineering

8.7K Views.  Tufts University School of Medicine. We describe a 3D culture model of the human breast epithelium that is suitable to study hormone action.

Video: A Hormone-responsive 3D Culture Model of the Human Mammary Gland Epithelium

A Simple Hanging Drop Cell Culture Protocol for Generation of 3D Spheroids

Studies of cell-cell cohesion and cell-substratum adhesion have historically been performed on monolayer cultures adherent to rigid substrates. Cells within a tissue, however, are typically encased within a closely packed tissue mass in which cells establish intimate connections with many near-neighbors and with extracellular matrix components. Accordingly, the chemical milieu and physical forces experienced by cells within a 3D tissue are fundamentally different than those experienced by cells grown in monolayer culture. This has been shown to markedly impact cellular morphology and signaling. Several methods have been devised to generate 3D cell cultures including encapsulation of cells in collagen gels1or in biomaterial scaffolds2. Such methods, while useful, do not recapitulate the intimate direct cell-cell adhesion architecture found in normal tissues. Rather, they more closely approximate culture systems in which single cells are loosely dispersed within a 3D meshwork of ECM products. Here, we describe a simple method in which cells are placed in hanging drop culture and incubated under physiological conditions until they form true 3D spheroids in which cells are in direct contact with each other and with extracellular matrix components. The method requires no specialized equipment and can be adapted to include addition of any biological agent in very small quantities that may be of interest in elucidating effects on cell-cell or cell-ECM interaction. The method can also be used to co-culture two (or more) different cell populations so as to elucidate the role of cell-cell or cell-ECM interactions in specifying spatial relationships between cells. Cell-cell cohesion and cell-ECM adhesion are the cornerstones of studies of embryonic development, tumor-stromal cell interaction in malignant invasion, wound healing, and for applications to tissue engineering. This simple method will provide a means of generating tissue-like cellular aggregates for measurement of biomechanical properties or for molecular and biochemical analysis in a physiologically relevant model.

We describe a simple, rapid method of generating 3D tissue-like spheroids and their potential application to quantify differences in cell-cell interactions.

Studies of cell-cell cohesion and cell-substratum adhesion have historically been performed on monolayer cultures adherent to rigid substrates. Cells ...

Rotating Cell Culture Systems for Human Cell Culture: Human Trophoblast Cells as a Model

The field of human trophoblast research aids in understanding the complex environment established during placentation. Due to the nature of these studies, human in vivo experimentation is impossible. A combination of primary cultures, explant cultures and trophoblast cell lines1 support our understanding of invasion of the uterine wall2 and remodeling of uterine spiral arteries3,4 by extravillous trophoblast cells (EVTs), which is required for successful establishment of pregnancy. Despite the wealth of knowledge gleaned from such models, it is accepted that in vitro cell culture models using EVT-like cell lines display altered cellular properties when compared to their in vivo counterparts5,6. Cells cultured in the rotating cell culture system (RCCS) display morphological, phenotypic, and functional properties of EVT-like cell lines that more closely mimic differentiating in utero EVTs, with increased expression of genes mediating invasion (e.g. matrix metalloproteinases (MMPs)) and trophoblast differentiation7,8,9. The Saint Georges Hospital Placental cell Line-4 (SGHPL-4) (kindly donated by Dr. Guy Whitley and Dr. Judith Cartwright) is an EVT-like cell line that was used for testing in the RCCS.
The design of the RCCS culture vessel is based on the principle that organs and tissues function in a three-dimensional (3-D) environment. Due to the dynamic culture conditions in the vessel, including conditions of physiologically relevant shear, cells grown in three dimensions form aggregates based on natural cellular affinities and differentiate into organotypic tissue-like assemblies10,11,12 . The maintenance of a fluid orbit provides a low-shear, low-turbulence environment similar to conditions found in vivo. Sedimentation of the cultured cells is countered by adjusting the rotation speed of the RCCS to ensure a constant free-fall of cells. Gas exchange occurs through a permeable hydrophobic membrane located on the back of the bioreactor. Like their parental tissue in vivo, RCCS-grown cells are able to respond to chemical and molecular gradients in three dimensions (i.e. at their apical, basal, and lateral surfaces) because they are cultured on the surface of porous microcarrier beads. When grown as two-dimensional monolayers on impermeable surfaces like plastic, cells are deprived of this important communication at their basal surface. Consequently, the spatial constraints imposed by the environment profoundly affect how cells sense and decode signals from the surrounding microenvironment, thus implying an important role for the 3-D milieu13.
We have used the RCCS to engineer biologically meaningful 3-D models of various human epithelial tissues7,14,15,16. Indeed, many previous reports have demonstrated that cells cultured in the RCCS can assume physiologically relevant phenotypes that have not been possible with other models10,17-21. In summary, culture in the RCCS represents an easy, reproducible, high-throughput platform that provides large numbers of differentiated cells that are amenable to a variety of experimental manipulations. 
In the following protocol, using EVTs as an example, we clearly describe the steps required to three-dimensionally culture adherent cells in the RCCS.

Traditional, two dimensional cell culture techniques often result in altered characteristics with respect to differentiation markers, cytokines and growth factors. Three-dimensional cell culture in the rotating cell culture system (RCCS) reestablishes expression of many of these factors as shown here with an extravillous trophoblast cell line.

The field of human trophoblast research aids in  understanding the complex environment established during placentation. Due to the  nature of these ...

Tissue Engineering of a Human 3D in vitro Tumor Test System

Cancer is one of the leading causes of death worldwide. Current therapeutic strategies are predominantly developed in 2D culture systems, which inadequately reflect physiological conditions in vivo. Biological 3D matrices provide cells an environment in which cells can self-organize, allowing the study of tissue organization and cell differentiation. Such scaffolds can be seeded with a mixture of different cell types to study direct 3D cell-cell-interactions. To mimic the 3D complexity of cancer tumors, our group has developed a 3D in vitro tumor test system.	
	Our 3D tissue test system models the in vivo situation of malignant peripheral nerve sheath tumors (MPNSTs), which we established with our decellularized porcine jejunal segment derived biological vascularized scaffold (BioVaSc). In our model, we reseeded a modified BioVaSc matrix with primary fibroblasts, microvascular endothelial cells (mvECs) and the S462 tumor cell line. For static culture, the vascular structure of the BioVaSc is removed and the remaining scaffold is cut open on one side (Small Intestinal Submucosa SIS-Muc). The resulting matrix is then fixed between two metal rings (cell crowns).	
	Another option is to culture the cell-seeded SIS-Muc in a flow bioreactor system that exposes the cells to shear stress. Here, the bioreactor is connected to a peristaltic pump in a self-constructed incubator. A computer regulates the arterial oxygen and nutrient supply via parameters such as blood pressure, temperature, and flow rate. This setup allows for a dynamic culture with either pressure-regulated pulsatile or constant flow.	
	In this study, we could successfully establish both a static and dynamic 3D culture system for MPNSTs. The ability to model cancer tumors in a more natural 3D environment will enable the discovery, testing, and validation of future pharmaceuticals in a human-like model.

Tissue Engineering of a Human 3D in vitro Tumor Test System

Methods to create human 3D tumor tissues as test systems are described. These technologies are based on a decellularized Biological Vascularized Scaffold (BioVaSc), primary human cells and a tumor cell line, which can be cultured under static as well as under dynamic conditions in a flow bioreactor.

Cancer is one of the leading causes of death worldwide.  Current therapeutic strategies are predominantly developed in 2D culture  systems, which ...

Production, Characterization and Potential Uses of a 3D Tissue-engineered Human Esophageal Mucosal Model

The incidence of both esophageal adenocarcinoma and its precursor, Barrett&#8217;s Metaplasia, are rising rapidly in the western world. Furthermore esophageal adenocarcinoma generally has a poor prognosis, with little improvement in survival rates in recent years. These are difficult conditions to study and there has been a lack of suitable experimental platforms to investigate disorders of the esophageal mucosa.
A model of the human esophageal mucosa has been developed in the MacNeil laboratory which, unlike conventional 2D cell culture systems, recapitulates the cell-cell and cell-matrix interactions present in vivo and produces a mature, stratified epithelium similar to that of the normal human esophagus. Briefly, the model utilizes non-transformed normal primary human esophageal fibroblasts and epithelial cells grown within a porcine-derived acellular esophageal scaffold. Immunohistochemical characterization of this model by CK4, CK14, Ki67 and involucrin staining demonstrates appropriate recapitulation of the histology of the normal human esophageal mucosa.
This model provides a robust, biologically relevant experimental model of the human esophageal mucosa. It can easily be manipulated to investigate a number of research questions including the effectiveness of pharmacological agents and the impact of exposure to environmental factors such as alcohol, toxins, high temperature or gastro-esophageal refluxate components. The model also facilitates extended culture periods not achievable with conventional 2D cell culture, enabling, inter alia, the study of the impact of repeated exposure of a mature epithelium to the agent of interest for up to 20 days. Furthermore, a variety of cell lines, such as those derived from esophageal tumors or Barrett&#8217;s Metaplasia, can be incorporated into the model to investigate processes such as tumor invasion and drug responsiveness in a more biologically relevant environment.

This manuscript describes the production, characterization and potential uses of a tissue engineered 3D esophageal construct prepared from normal primary human esophageal fibroblast and squamous epithelial cells seeded within a de-cellularized porcine scaffold. The results demonstrate the formation of a mature stratified epithelium similar to the normal human esophagus.

The incidence of both esophageal adenocarcinoma and its precursor, Barrett&#8217;s Metaplasia, are rising rapidly in the western world. Furthermore ...

Preparation of 3D Collagen Gels and Microchannels for the Study of 3D Interactions In Vivo

Historically, most cellular processes have been studied in only 2 dimensions. While these studies have been informative about general cell signaling mechanisms, they neglect important cellular cues received from the structural and mechanical properties of the local microenvironment and extracellular matrix (ECM). To understand how cells interact within a physiological ECM, it is important to study them in the context of 3 dimensional assays. Cell migration, cell differentiation, and cell proliferation are only a few processes that have been shown to be impacted by local changes in the mechanical properties of a 3-dimensional ECM. Collagen I, a core fibrillar component of the ECM, is more than a simple structural element of a tissue. Under normal conditions, mechanical cues from the collagen network direct morphogenesis and maintain cellular structures. In diseased microenvironments, such as the tumor microenvironment, the collagen network is often dramatically remodeled, demonstrating altered composition, enhanced deposition and altered fiber organization. In breast cancer, the degree of fiber alignment is important, as an increase in aligned fibers perpendicular to the tumor boundary has been correlated to poorer patient prognosis1. Aligned collagen matrices result in increased dissemination of tumor cells via persistent migration2,3. The following is a simple protocol for embedding cells within a 3-dimensional, fibrillar collagen hydrogel. This protocol is readily adaptable to many platforms, and can reproducibly generate both aligned and random collagen matrices for investigation of cell migration, cell division, and other cellular processes in a tunable, 3-dimensional, physiological microenvironment.

Preparation of 3D Collagen Gels and Microchannels for the Study of 3D Interactions In Vivo

Collagen is a core component of the ECM, and provides essential cues for several cellular processes ranging from migration to differentiation and proliferation. Provided here is a protocol for embedding cells within 3D collagen hydrogels, and a more advanced technique for generating randomized or aligned collagen matrices using PDMS microchannels.

Historically, most cellular processes have been studied in only 2 dimensions.  While these studies have been informative about general cell signaling ...

Tunable Hydrogels from Pulmonary Extracellular Matrix for 3D Cell Culture

Here we present a method for establishing multiple component cell culture hydrogels for in vitro lung cell culture. Beginning with healthy en bloc lung tissue from porcine, rat, or mouse, the tissue is perfused and submerged in subsequent chemical detergents to remove the cellular debris. Histological comparison of the tissue before and after processing confirms removal of over 95% of double stranded DNA and alpha galactosidase staining suggests the majority of cellular debris is removed. After decellularization, the tissue is lyophilized and then cryomilled into a powder. The matrix powder is digested for 48 hr in an acidic pepsin digestion solution and then neutralized to form the pregel solution. Gelation of the pregel solution can be induced by incubation at 37 &#176;C and can be used immediately following neutralization or stored at 4 &#176;C for up to two weeks. Coatings can be formed using the pregel solution on a non-treated plate for cell attachment. Cells can be suspended in the pregel prior to self-assembly to achieve a 3D culture, plated on the surface of a formed gel from which the cells can migrate through the scaffold, or plated on the coatings. Alterations to the strategy presented can impact gelation temperature, strength, or protein fragment sizes. Beyond hydrogel formation, the hydrogel stiffness may be increased using genipin.

This is a method to create a 3-dimensional cell culture scaffold from pulmonary extracellular matrix. Intact lung is processed into hydrogels that can support the growth of cells in three-dimensions.

Here we present a method for establishing multiple component cell culture hydrogels for in vitro lung cell culture. Beginning with healthy en bloc lung ...

Intraductal Delivery to the Rabbit Mammary Gland

Localized intraductal treatments for breast cancer offer potential advantages, including efficient delivery to the tumor and reduced systemic toxicity and adverse effects1,2,3,4,5,6,7. However, several challenges remain before these treatments can be applied more widely. The development and validation of intraductal therapeutics in an appropriate animal model facilitate the development of intraductal therapeutic strategies for patients. While the mouse mammary gland has been widely used as a model system of mammary development and tumorigenesis, the anatomy is distinct from the human gland. A larger animal model, such as the rabbit, may serve as a better model for mammary gland structure and intraductal therapeutic development. In contrast to mice, in which ten ductal trees are spatially distributed along the body axis, each terminating in a separate teat, the rabbit mammary gland more closely resembles the human gland, with multiple overlapping ductal systems that exit through separate openings in one teat. Here, we present minimally invasive methods for the delivery of reagents directly into the rabbit mammary duct and for visualization of the delivery itself with high-resolution ultrasound imaging.

Here, we describe a technique for the localized delivery of reagents to the rabbit mammary gland via an intraductal injection. In addition, we describe a protocol for visualization and the confirmation of delivery by high-resolution ultrasound imaging of contrast agents.

Localized intraductal treatments for breast cancer offer potential advantages, including efficient delivery to the tumor and reduced systemic toxicity and ...

High Resolution 3D Imaging of the Human Pancreas Neuro-insular Network

Using traditional histological methods, researchers are hampered in their ability to image whole tissues or organs in large-scale 3D. Histological sections are generally limited to &#60;20 &#181;m as formalin fixed paraffin section on glass slides or &#60;500 &#181;m for free-floating fixed sections. Therefore, extensive efforts are required for serial sectioning and large-scale image reconstruction methods to recreate 3D for samples &#62;500 &#181;m using traditional methods. In addition, light scatters from macromolecules within tissues, particularly lipids, prevents imaging to a depth &#62;150 &#181;m with most confocal microscopes. To reduce light scatter and to allow for deep tissue imaging using simple confocal microscopy, various optical clearing methods have been developed that are relevant for rodent and human tissue samples fixed by immersion. Several methods are related and use protein crosslinking with acrylamide and tissue clearing with sodium dodecyl sulfate (SDS). Other optical clearing techniques used various solvents though each modification had various advantages and disadvantages. Here, an optimized passive optical clearing method is described for studies of the human pancreas innervation and specifically for interrogation of the innervation of human islets.

Here, we present a protocol to image human pancreas sections in three dimensions (3D) using optimized passive clearing methods. This manuscript demonstrates these procedures for passive optical clearing followed by multiple immunofluorescence staining to identify key elements of the autonomic and sensory neural networks innervating human islets.

Using traditional histological methods, researchers are hampered in their ability to image whole tissues or organs in large-scale 3D. Histological ...

Construction of a Multilayered Mesenchymal Stem Cell Sheet with a 3D Dynamic Culture System

Stem cell therapy shows a promising future in regenerating injured organ and tissues, and the cell sheet technique has been developed to improve the low cell retention and poor survival within the target zone. However, during the in vitro construction process, a solution for maintaining stem cell bioactivity and increasing the cell amount within the cell sheet is urgently needed. Here, this protocol presents a method for constructing a multilayered cell sheet with favorable stem cell bioactivity and optimal operability. Decellularized porcine pericardium (DPP) is prepared by phospholipase A2 (PLA2) decellularization method as the cell sheet scaffold, and rat bone marrow mesenchymal stem cells (BMSCs) are isolated and expanded as the seeded cells. The temporary multilayered cell sheet structure is constructed by using RAD16-I peptide hydrogel. Finally, the cell sheet is cultured with a dynamic perfusion system to stabilize the three-dimensional (3D) structure, and the cell sheet could be obtained following a 48-hour culture in vitro. This protocol provides an efficient and feasible method for constructing a multilayered stem cell sheet, and the cell sheet could be developed as a favorable stem cell therapy product in the future.

This article provides an efficient and feasible method for constructing multilayered stem cell sheets with favorable stem cell property.

Stem cell therapy shows a promising future in regenerating injured organ and tissues, and the cell sheet technique has been developed to improve the low ...

Growth and Characterization of Irradiated Organoids from Mammary Glands

Organoids derived from the digested tissue are multicellular three-dimensional (3D) constructs that better recapitulate in vivo conditions than cell monolayers. Although they cannot completely model in vivo complexity, they retain some functionality of the original organ. In cancer models, organoids are commonly used to study tumor cell invasion. This protocol aims to develop and characterize organoids from the normal and irradiated mouse mammary gland tissue to evaluate the radiation response in normal tissues. These organoids can be applied to future in vitro cancer studies to evaluate tumor cell interactions with irradiated organoids. Mammary glands were resected, irradiated to 20 Gy and digested in a collagenase VIII solution. Epithelial organoids were separated via centrifugal differentiation, and 3D organoids were developed in 96-well low-adhesion microplates. Organoids expressed the characteristic epithelial marker cytokeratin 14. Macrophage interaction with the organoids was observed in co-culture experiments. This model may be useful for studying tumor-stromal interactions, infiltration of immune cells, and macrophage polarization within an irradiated microenvironment.

Organoids developed from mouse mammary glands were irradiated and characterized to assess epithelial traits and interactions with immune cells. Irradiated organoids can be used to better evaluate cell-cell interactions that may lead to tumor cell recruitment in irradiated normal tissue.

Organoids derived from the digested tissue are multicellular three-dimensional (3D) constructs that better recapitulate in vivo conditions than cell ...