Characterization of primary breast carcinomas grown in three-dimensional cultures

Background. The process of progression and spread of cancer is not easily replicated in animal models and is difficult to examine in vitro. This is particularly true for human primary breast carcinoma cells, whose in vitro growth is shown to be limited to one or two passages in monolayer culture. Three-dimensional (3D) growth of breast cancer cells suggests that cell aggregates grown in this manner have many similarities to in vivo behavior. Materials and methods. Primary tumors obtained from five breast cancer patients were grown in 3D cultures using the rotating-wall vessel bioreactor. Tumor aggregates were assessed for DNA ploidy, cell cycle kinetics, and expression of tumor markers and cytokines. Comparisons between fresh tumor cells and 3D aggregates were performed. Results. All five breast cancers were found to be aneuploid after 3D culture, with elevated S-phase fractions. Reverse transcription-polymerase chain reaction analyses revealed mRNA expression of HER2/ neu, H-ras, K-ras, p53, transforming growth factor-a, transforming growth factor-beta, interleukin-1, and interleukin-6 in 3D-grown tumor cells; in most cases, expression appeared increased when compared with mRNA obtained from freshly isolated primary tumor cells. Conclusions. After prolonged 3D growth in the rotating wall bioreactor, complex tissue-like constructs of primary breast tumor cells exhibited significantly increased proliferative activity in conjunction with oncogene activation and developed into aggressive aneuploid populations. (C) 2007 Elsevier Inc. All rights reserved.