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

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Research

JoVE Journal

Bioengineering

8.8K 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

Differentiation of Mouse Breast Epithelial HC11 and EpH4 Cells

Cadherins play an important role in the regulation of cell differentiation as well as neoplasia. Here we describe the origins and methods of the induction of differentiation of two mouse breast epithelial cell lines, HC11 and EpH4, and their use to study complementary stages of mammary gland development and neoplastic transformation.
The HC11 mouse breast epithelial cell line originated from the mammary gland of a pregnant Balb/c mouse. It differentiates when grown to confluence attached to a plastic Petri dish surface in medium containing fetal calf serum and Hydrocortisone, Insulin and Prolactin (HIP medium). Under these conditions, HC11 cells produce the milk proteins &#946;-casein and whey acidic protein (WAP), similar to lactating mammary epithelial cells, and form rudimentary mammary gland-like structures termed &#34;domes&#34;.
The EpH4 cell line was derived from spontaneously immortalized mouse mammary gland epithelial cells isolated from a pregnant Balb/c mouse. Unlike HC11, EpH4 cells can fully differentiate into spheroids (also called mammospheres) when cultured under three-dimensional (3D) growth conditions in HIP medium. Cells are trypsinized, suspended in a 20% matrix consisting of a mixture of extracellular matrix proteins produced by Engelbreth-Holm-Swarm (EHS) mouse sarcoma cells, plated on top of a layer of concentrated matrix coating a plastic Petri dish or multiwell plate, and covered with a layer of 10% matrix-containing HIP medium. Under these conditions, EpH4 cells form hollow spheroids that exhibit apical-basal polarity, a hollow lumen, and produce &#946;-casein and WAP.
Using these techniques, our results demonstrated that the intensity of the cadherin/Rac signal is critical for the differentiation of HC11 cells. While Rac1 is necessary for differentiation and low levels of activated RacV12 increase differentiation, high RacV12 levels block differentiation while inducing neoplasia. In contrast, EpH4 cells represent an earlier stage in mammary epithelial differentiation, which is inhibited by even low levels of RacV12.

We describe techniques for differentiation induction of two breast epithelial lines, HC11 and EpH4. While both require fetal calf serum, insulin, and prolactin to produce milk proteins, EpH4 cells can fully differentiate into mammospheres in three-dimensional culture. These complementary models are useful for signal transduction studies of differentiation and neoplasia.

Cadherins play an important role in the regulation of cell differentiation as well as neoplasia. Here we describe the origins and methods of the induction ...

Cancer Research

A Three-dimensional Tissue Culture Model to Study Primary Human Bone Marrow and its Malignancies

Tissue culture has been an invaluable tool to study many aspects of cell function, from normal development to disease. Conventional cell culture methods rely on the ability of cells either to attach to a solid substratum of a tissue culture dish or to grow in suspension in liquid medium. Multiple immortal cell lines have been created and grown using such approaches, however, these methods frequently fail when primary cells need to be grown ex vivo. Such failure has been attributed to the absence of the appropriate extracellular matrix components of the tissue microenvironment from the standard systems where tissue culture plastic is used as a surface for cell growth. Extracellular matrix is an integral component of the tissue microenvironment and its presence is crucial for the maintenance of physiological functions such as cell polarization, survival, and proliferation. Here we present a 3-dimensional tissue culture method where primary bone marrow cells are grown in extracellular matrix formulated to recapitulate the microenvironment of the human bone (rBM system). Embedded in the extracellular matrix, cells are supplied with nutrients through the medium supplemented with human plasma, thus providing a comprehensive system where cell survival and proliferation can be sustained for up to 30 days while maintaining the cellular composition of the primary tissue. Using the rBM system we have successfully grown primary bone marrow cells from normal donors and patients with amyloidosis, and various hematological malignancies. The rBM system allows for direct, in-matrix real time visualization of the cell behavior and evaluation of preclinical efficacy of novel therapeutics. Moreover, cells can be isolated from the rBM and subsequently used for in vivo transplantation, cell sorting, flow cytometry, and nucleic acid and protein analysis. Taken together, the rBM method provides a reliable system for the growth of primary bone marrow cells under physiological conditions.

In standard culture methods cells are taken out of their physiological environment and grown on the plastic surface of a dish. To study the behavior of primary human bone marrow cells we created a 3-D culture system where cells are grown under conditions recapitulating the native microenvironment of the tissue.

Tissue culture has been an invaluable tool to study many aspects of cell function, from normal development to disease. Conventional cell culture methods ...

Medicine

Phospholipid Mediator Induced Transformation in Three-Dimensional Cultures

Several models have been developed to study cancer, such as rodent models and established cell lines. Valuable insights into carcinogenesis have been provided by studies using these models. Cell lines have provided an understanding of the deregulation of molecular signaling associated with breast tumorigenesis, while rodent models are widely used to study cellular and molecular characteristics of breast cancer in vivo. The establishment of 3D cultures of breast epithelial and cancerous cells aids in bridging the gap between in vivo and in vitro models by mimicking the in vivo conditions in vitro. This model can be used to understand the deregulation of complex molecular signaling events and the cellular characteristics during breast carcinogenesis. Here, a 3D culture system is modified to study a phospholipid mediator-induced (Platelet Activating Factor, PAF) transformation. Immunomodulators and other secreted molecules play a major role in tumor initiation and progression in the breast. In the present study, 3D acinar cultures of breast epithelial cells are exposed to PAF exhibited transformation characteristics such as loss of polarity and altered cellular characteristics. This 3D culture system will assist in shedding light on genetic and/or epigenetic perturbations induced by various small molecule entities in the tumor microenvironment. Additionally, this system will also provide a platform for the identification of novel as well as known genes that may be involved in the process of transformation.

The present protocol describes the setting up of 3D 'on top' cultures of a non-transformed breast epithelial cell line, MCF10A, that has been modified to study Platelet Activating Factor (PAF) induced transformation. Immuno-fluorescence has been used to assess the transformation and is discussed in detail.

Several models have been developed to study cancer, such as rodent models and established cell lines. Valuable insights into carcinogenesis have been ...

Three Dimensional Cultures: A Tool To Study Normal Acinar Architecture vs. Malignant Transformation Of Breast Cells

Invasive breast carcinomas are a group of malignant epithelial tumors characterized by the invasion of adjacent tissues and propensity to metastasize. The interplay of signals between cancer cells and their microenvironment exerts a powerful influence on breast cancer growth and biological behavior1. However, most of these signals from the extracellular matrix are lost or their relevance is understudied when cells are grown in two dimensional culture (2D) as a monolayer. In recent years, three dimensional (3D) culture on a reconstituted basement membrane has emerged as a method of choice to recapitulate the tissue architecture of benign and malignant breast cells. Cells grown in 3D retain the important cues from the extracellular matrix and provide a physiologically relevant ex&#160;vivo system2,3. Of note, there is growing evidence suggesting that cells behave differently when grown in 3D as compared to 2D4. 3D culture can be effectively used as a means to differentiate the malignant phenotype from the benign breast phenotype and for underpinning the cellular and molecular signaling involved3. One of the distinguishing characteristics of benign epithelial cells is that they are polarized so that the apical cytoplasm is towards the lumen and the basal cytoplasm rests on the basement membrane. This apico-basal polarity is lost in invasive breast carcinomas, which are characterized by cellular disorganization and formation of anastomosing and branching tubules that haphazardly infiltrates the surrounding stroma. These histopathological differences between benign gland and invasive carcinoma can be reproduced in 3D6,7. Using the appropriate read-outs like the quantitation of single round acinar structures, or differential expression of validated molecular markers for cell proliferation, polarity and apoptosis in combination with other molecular and cell biology techniques, 3D culture can provide an important tool to better understand the cellular changes during malignant transformation and for delineating the responsible signaling.

Three dimensional culture of mammary epithelial cells on a reconstituted basement membrane is a useful method to recapitulate the in vivo architecture of the benign breast, and to differentiate the malignant phenotype from the benign breast phenotype. Importantly, this system can be applied to study invasive carcinomas in other tissues.

Invasive breast carcinomas are a group of malignant epithelial tumors characterized by the invasion of adjacent tissues and propensity to metastasize. The ...

Quantification of Breast Cancer Cell Invasiveness Using a Three-dimensional (3D) Model

It is now well known that the cellular and tissue microenvironment are critical regulators influencing tumor initiation and progression. Moreover, the extracellular matrix (ECM) has been demonstrated to be a critical regulator of cell behavior in culture and homeostasis in vivo. The current approach of culturing cells on two-dimensional (2D), plastic surfaces results in the disturbance and loss of complex interactions between cells and their microenvironment. Through the use of three-dimensional (3D) culture assays, the conditions for cell-microenvironment interaction are established resembling the in vivo microenvironment. This article provides a detailed methodology to grow breast cancer cells in a 3D basement membrane protein matrix, exemplifying the potential of 3D culture in the assessment of cell invasion into the surrounding environment. In addition, we discuss how these 3D assays have the potential to examine the loss of signaling molecules that regulate epithelial morphology by immunostaining procedures. These studies aid to identify important mechanistic details into the processes regulating invasion, required for the spread of breast cancer.

Quantification of Breast Cancer Cell Invasiveness Using a Three-dimensional 3D Model

This article provides detailed methodologies for the use of three-dimensional (3D) assays to quantify breast cancer cell invasion. Specifically, we discuss the procedures required to set up such assays, quantification, and data analysis, as well as methods to examine the loss of membrane integrity that occurs when cells invade.

It is now well known that the cellular and tissue microenvironment are critical regulators influencing tumor initiation and progression. Moreover, the ...

Generating and Imaging Mouse and Human Epithelial Organoids from Normal and Tumor Mammary Tissue Without Passaging

Organoids are a reliable method for modeling organ tissue due to their self-organizing properties and retention of function and architecture after propagation from primary tissue or stem cells. This method of organoid generation forgoes single-cell differentiation through multiple passages and instead uses differential centrifugation to isolate mammary epithelial organoids from mechanically and enzymatically dissociated tissues. This protocol provides a streamlined technique for rapidly producing small and large epithelial organoids from both mouse and human mammary tissue in addition to techniques for organoid embedding in collagen and basement extracellular matrix. Furthermore, instructions for in-gel fixation and immunofluorescent staining are provided for the purpose of visualizing organoid morphology and density. These methodologies are suitable for myriad downstream analyses, such as co-culturing with immune cells and ex vivo metastasis modeling via collagen invasion assay. These analyses serve to better elucidate cell-cell behavior and create a more complete understanding of interactions within the tumor microenvironment.

This protocol discusses an approach for generating epithelial organoids from primary normal and tumor mammary tissue through differential centrifugation. Furthermore, instructions are included for three-dimensional culturing as well as immunofluorescent imaging of embedded organoids.

Organoids are a reliable method for modeling organ tissue due to their self-organizing properties and retention of function and architecture after ...

Engineering Three-dimensional Epithelial Tissues Embedded within Extracellular Matrix

The architecture of branched organs such as the lungs, kidneys, and mammary glands arises through the developmental process of branching morphogenesis, which is regulated by a variety of soluble and physical signals in the microenvironment. Described here is a method created to study the process of branching morphogenesis by forming engineered three-dimensional (3D) epithelial tissues of defined shape and size that are completely embedded within an extracellular matrix (ECM). This method enables the formation of arrays of identical tissues and enables the control of a variety of environmental factors, including tissue geometry, spacing, and ECM composition. This method can also be combined with widely used techniques such as traction force microscopy (TFM) to gain more information about the interactions between cells and their surrounding ECM. The protocol can be used to investigate a variety of cell and tissue processes beyond branching morphogenesis, including cancer invasion.

This manuscript describes a soft lithography-based technique to engineer uniform arrays of three-dimensional (3D) epithelial tissues of defined geometry surrounded by extracellular matrix. This method is amenable to a wide variety of cell types and experimental contexts and allows for high-throughput screening of identical replicates.

The architecture of branched organs such as the lungs, kidneys, and mammary glands arises through the developmental process of branching morphogenesis, ...

Generation of Mosaic Mammary Organoids by Differential Trypsinization

Organoids offer self-organizing, three-dimensional tissue structures that recapitulate physiological processes in the convenience of a dish. The murine mammary gland is composed of two distinct epithelial cell compartments, serving different functions: the outer, contractile myoepithelial compartment and the inner, secretory luminal compartment. Here, we describe a method by which the cells comprising these compartments are isolated and then combined to investigate their individual lineage contributions to mammary gland morphogenesis and differentiation. The method is simple and efficient and does not require sophisticated separation technologies such as fluorescence activated cell sorting. Instead, we harvest and enzymatically digest the tissue, seed the epithelium on adherent tissue culture dishes, and then use differential trypsinization to separate myoepithelial from luminal cells with ~90% purity. The cells are then plated in an extracellular matrix where they organize into bilayered, three-dimensional (3D) organoids that can be differentiated to produce milk after 10 days in culture. To test the effects of genetic mutations, cells can be harvested from wild type or genetically engineered mouse models, or they can be genetically manipulated prior to 3D culture. This technique can be used to generate mosaic organoids that allow investigation of gene function specifically in the luminal or myoepithelial compartment.

The mammary gland is a bilayered structure, comprising outer myoepithelial and inner luminal epithelial cells. Presented is a protocol to prepare organoids using differential trypsinization. This efficient method allows researchers to separately manipulate these two cell types to explore questions concerning their roles in mammary gland form and function.

Organoids offer self-organizing, three-dimensional tissue structures that recapitulate physiological processes in the convenience of a dish. The murine ...

Developmental Biology

An Ex vivo Model to Study Hormone Action in the Human Breast

The study of hormone action in the human breast has been hampered by lack of adequate model systems. Upon in vitro culture, primary mammary epithelial cells tend to lose hormone receptor expression. Widely used hormone receptor positive breast cancer cell lines are of limited relevance to the in vivo situation. Here, we describe an ex vivo model to study hormone action in the human breast. Fresh human breast tissue specimens from surgical discard material such as reduction mammoplasties or mammectomies are mechanically and enzymatically digested to obtain tissue fragments containing ducts and lobules and multiple stromal cell types. These tissue microstructures kept in basal medium without growth factors preserve their intercellular contacts, the tissue architecture, and remain hormone responsive for several days. They are readily processed for RNA and protein extraction, histological analysis or stored in freezing medium. Fluorescence activated cell sorting (FACS) can be used to enrich for specific cell populations. This protocol provides a straightforward, standard approach for translational studies with highly complex, varied human specimens.

An Ex vivo Model to Study Hormone Action in the Human Breast

We have developed a novel ex vivo model to study hormone action in the human breast. It is based on tissue microstructures isolated from surgical breast tissue specimens which preserve tissue architecture, intercellular interactions, and paracrine signaling.

The study of hormone action in the human breast has been hampered by lack of adequate model systems. Upon in vitro culture, primary mammary epithelial ...

Isolation of Mammary Epithelial Cells from Three-dimensional Mixed-cell Spheroid Co-culture

While enormous efforts have gone into identifying signaling pathways and molecules involved in normal and malignant cell behaviors1-2, much of this work has been done using classical two-dimensional cell culture models, which allow for easy cell manipulation. It has become clear that intracellular signaling pathways are affected by extracellular forces, including dimensionality and cell surface tension3-4. Multiple approaches have been taken to develop three-dimensional models that more accurately represent biologic tissue architecture3. While these models incorporate multi-dimensionality and architectural stresses, study of the consequent effects on cells is less facile than in two-dimensional tissue culture due to the limitations of the models and the difficulty in extracting cells for subsequent analysis.
The important role of the microenvironment around tumors in tumorigenesis and tumor behavior is becoming increasingly recognized4. Tumor stroma is composed of multiple cell types and extracellular molecules. During tumor development there are bidirectional signals between tumor cells and stromal cells5. Although some factors participating in tumor-stroma co-evolution have been identified, there is still a need to develop simple techniques to systematically identify and study the full array of these signals6. Fibroblasts are the most abundant cell type in normal or tumor-associated stromal tissues, and contribute to deposition and maintenance of basement membrane and paracrine growth factors7.
Many groups have used three dimensional culture systems to study the role of fibroblasts on various cellular functions, including tumor response to therapies, recruitment of immune cells, signaling molecules, proliferation, apoptosis, angiogenesis, and invasion8-15. We have optimized a simple method for assessing the effects of mammary fibroblasts on mammary epithelial cells using a commercially available extracellular matrix model to create three-dimensional cultures of mixed cell populations (co-cultures)16-22. With continued co-culture the cells form spheroids with the fibroblasts clustering in the interior and the epithelial cells largely on the exterior of the spheroids and forming multi-cellular projections into the matrix. Manipulation of the fibroblasts that leads to altered epithelial cell invasiveness can be readily quantified by changes in numbers and length of epithelial projections23. Furthermore, we have devised a method for isolating epithelial cells out of three-dimensional co-culture that facilitates analysis of the effects of fibroblast exposure on epithelial behavior. We have found that the effects of co-culture persist for weeks after epithelial cell isolation, permitting ample time to perform multiple assays. This method is adaptable to cells of varying malignant potential and requires no specialized equipment. This technique allows for rapid evaluation of in vitro cell models under multiple conditions, and the corresponding results can be compared to in vivo animal tissue models as well as human tissue samples.

A simple method is described for analyzing effects of tissue fibroblasts on associated epithelial cells. The combination of this method and three-dimensional tissue culture can facilitate analysis of cells after isolation from 3D. The technique is applicable to cells of varying malignant potential, allowing systematic study of effects of tumor-associated stroma on tumor cells.

While enormous efforts have gone into identifying signaling pathways and molecules involved in normal and malignant cell behaviors1-2, much of this work ...

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

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