Cultrex Reduced Growth Factor Basement Membrane Extract, Type 2, Pathclear

Many cell lines and tumor biopsy specimens (usually cut into small fragments) have been found to grow in vivo when implanted with Cultrex^® BME. These include melanoma, intestinal, prostate, breast, lung, renal, and liver cancers as well as the 3T3 mouse embryonic fibroblast cell line.

All epithelial and endothelial cells are in contact with a basement membrane matrix on at least one of their surfaces. By providing them with their natural matrix in vitro as a substrate for the cells that provides biological cues, the cells can assume a more physiological morphology (i.e. correct shape) and begin expression of cell-lineage specific proteins. Two-dimensional plastic surfaces, in combination with serum-containing media, cause cells to flatten, proliferate and de-differentiate.

Cultrex BME should be stored at or below -20°C for optimal stability. Preparation of working aliquots is recommended. Cultrex BME should be thawed overnight on ice at 4°C, however long term storage at 4°C is not recommended. Freeze/thaw cycles and gel-liquid phase transitions should be avoided, since they can compromise product integrity.

The Tube Formation Assay is based on the ability of endothelial cells to form three-dimensional capillary-like tubular structures when cultured on a hydrogel of reconstituted basement membrane, such as Cultrex Basement Membrane Extract (BME).

The Tube Formation Assay is the most widely used in vitro angiogenesis assay. The assay is rapid, inexpensive and quantifiable. It can be used to identify potentially angiogenic and anti-angiogenic factors, to determine endothelial cell phenotype, and to study pathways and mechanisms involved in angiogenesis. It can be performed in a high throughput mode to screen for a large number of compounds.

The Tube Formation Assay is specific for endothelial cells, either primary cells or immortalized cell lines. Only endothelial cells form capillary-like structures with a lumen inside. Other endothelial cell types form other structures.

The major variables associated with tube formation are composition of the Cultrex Basement Membrane Extract (BME) hydrogel, thickness of the hydrogel, cell density, composition of angiogenic factors in the assay medium, and assay period.

Cultrex Reduced Growth Factor BME (RGF BME) is generally used for testing compounds that promote angiogenesis because formation of capillary-like structures (tubes) is significantly less compared to non-growth factor reduced varieties of Cultrex BME. The Cultrex In Vitro Angiogeneis Assay (Tube Formation) includes a qualified production lot of Cultrex RGF BME that exhibits reduced background tube formation in the absence of angiogenic factors.

Primary endothelial cells, such as Human Umbilical Vein Endothelial Cells (HUVECs) form capillary-like structures in the absence of added angiogenic factors less often than immortalized endothelial cells. Generally, reducing the number of cells per cm² plated onto Cultrex BME will result in less background or spontaneous tube formation. Titrate the number of cells and find optimal conditions for your specific cell line. When endothelial cells fully form capillary structures in response to angiogenic activators, but not in their absence, you may proceed.

BME is known to have autofluorescence, but if appropriate controls are evaluated, background can be successfully subtracted. A BME only control well with no cells should be used to subtract the background fluorescence.