Background:

Traditional tissue culture procedures and animal studies have numerous limitations. Three-dimensional (3-D) cell culture helps bypass several of these limitations, and is becoming more and more popular. One major advantage of 3-D cell cultures is their well-defined geometry, which makes it possible to directly relate structure to function and which enables theoretical analyses. Combining different experimental approaches with molecular analysis has clearly demonstrated that, in comparison with conventional cultures, cells in 3-D cultures more closely resemble the in vivo situation with regard to cell shape and cellular environment.

For example, in breast cancer, 3-D cultures have been used for studies on molecular mechanisms involved in invasion and metastasis. The limitations of monolayer cell culture can be overcome to an extent by 3-D cell culture of epithelial cells. Unlike monolayer cultures, mammary epithelial cells grown in three dimensions recapitulate numerous features of breast epithelium in vivo, including the formation of acini-like spheroids with a hollow lumen and apicobasal polarization of cells making up these acini. Once oncogenes or other tumor initiating factors are introduced, these morphogenic processes will be disrupted and elicit distinct morphological phenotypes. Thus 3-D epithelial culture provides the appropriate structural and functional context fundamental for examining the biological activities of cancer genes.

Though the 3-D cell culture system has several advantages over traditional monolayer culture, at present, its high cost limits its use by many of the research laboratories. Currently, the most commonly used media is the reconstituted basement membrane derived from Engelbreth-Holm-Swarm (EHS) tumor which is commercially available as MatrigelTM. The Matrigel^TM^ medium is very expensive and is unaffordable to many of the research laboratories. Thus the need for an alternative economically viable 3-D cell culture medium is in high demand.

Development of the Egg-Based 3-D Cell Culture System:

During their search for a cost effective, easily accessible and reliable alternative for the currently used, expensive 3-D culture media, the developers came up with the idea of using egg white in 3-D cell culture. They decided to carry out cell culture using egg white as the supporting basement membrane, and they cultivated two different types of cells in their modified 3-D culture medium:

1. MCF10A, an immortalized normal breast cell line which forms acini-like structures in 3-D cell culture; and

2. MCF-7, another well-known breast cancer cell line which does not form acini-like structures in 3-D cell culture.

They found that the cells are growing in a similar fashion in the modified egg-white based 3-D cell culture system as compared to the Matrigel^TM^ media. They found that the MCF10A cells form the acini as observed with the Matrigel^TM^ media, and the MCF7 cells did not form the acini as observed with the Matrigel^TM^ media.

One of the typical characteristics with MCF10A in a 3-D culture model is its growth arrest and formation of a hollow lumen after two weeks of growth. To confirm the possibility of acini formation in their modified egg-based 3-D culture medium, they have taken confocal pictures of MCF10A cells at different time points after nuclei staining using Topro3, and have photos showing that the MCF10A cells do indeed form a hollow lumen with their modified egg-based 3-D culture system as observed with the Matrigel^TM^ media.

Altogether the developers’ observations suggest that egg-based 3-D cell culture medium can be used as an economic and easily available alternative for the Matrigel^TM^ cell culture medium.

File Number: BLG 06-081 

Web site: http://www.bcm.edu/blg/showned.cfm?06-081