Moreover, we performed experiments with primary cultures from human breast tumors in order to compare α-amylase effects on
different mammary cells from various sources and species. These investigations were expected to provide evidence if α-amylase serves Selleckchem GW786034 as a new candidate for breast cancer prophylaxis or therapy. Materials and methods Animals Female rats from two inbred rat strains, F344 and Lewis, were obtained from Charles River (Sulzfeld, Germany) at an age of about six weeks (42-45 days). In total, 18 F344 and 16 Lewis rats were used for five preparations per strain. Rats were housed in groups of 4-5 animals per cage with controlled conditions of temperature (23-24°C), humidity (about 50%), and light (12 h dark/light cycle; light off 6 p.m.). The experimental protocol was in line
with national and international ethical guidelines, conducted in compliance with the German Animal Welfare Act, and approved by the responsible governmental agency, selleck including approval by an animal NCT-501 clinical trial ethics committee. All efforts were made to minimize pain or discomfort of the animals. Human cells Primary human breast cancer-derived epithelial cells (HBCEC) from mammary carcinoma excisions were used to study the effect of salivary α-amylase in different mammary cells of human origin. Detailed information about derivation or source of these cells and their maintenance was described previously [32]. Cell preparation and culture Rats were killed at an age of 7-9 weeks by CO2-anesthesia and cervical dislocation for dissection of three paired mammary gland complexes (cranial cervical;
abdominal; cranial inguinal). Cell preparation of the rat mammary glands was done according to the protocol of Bissell´s group for mouse tissue [33] in a modified way. Prior to dissection of mammary gland complexes, skin and fur were cleaned with ethanol (70%) or Braunol® (Braun, Melsungen, Germany). Cells from about 20% of the animals, cleaned with ethanol, turned out to be infected mostly PD184352 (CI-1040) with fungi. The number of culture infections decreased from 20% to about 5% by use of the iodine-based disinfectant Braunol®. The mammary gland complexes were taken under sterile conditions and stored in ice-cold phosphate-buffered saline (PBS). For cell extraction, tissue was minced by scalpels and incubated in a pre-warmed enzymatic solution (0.2% trypsin, 0.2% collagenase A, 5% fetal calf serum, and 5 µg/ml gentamicin in Dulbecco´s Modified Eagle Medium with nutrient mixture F12 (DMEM/F12)) on a shaker for 70-90 min at 37°C. After centrifugation (1,500 rpm, 10 min), DNAse (40-50 U) was used for further cell dissociation (2-5 min, room temperature, manual shaking). Groups of epithelial cells were separated by pulse centrifugations from single cells that were supposed to be mainly fibroblasts.