Culture conditions modulate cell phenotype and cause selection of subpopulations in PC3 prostate cancer cell line

PC3 cell line contains different cell variants. A first variant grows as sp herical multicellular aggregates and shows anchorage-independent growth. A second valiant grows as single small rounds and shows anchorage-dependent g rowth without cell spreading. A third variant, representing the most abunda nt population, grows as adherent cells. These populations differ in alpha2 beta1 and alpha3 beta1 integrin expression with low levels in the suspended (S) cells, intermediate in partially adherent (R) cells and high in adhere nt cells (A). TPA, which up-regulates the expression of beta1 integrins, in creases invasiveness of cells. In addition, PC3 variants differ in MMP9 and uPA secretion and activity. High levels of TIMP1 and PAI1 present in S var iant reduce MMP9 and uPA activities, respectively. In conclusion, PC3 cell line shows variants with strong phenotypic heterogeneity reflecting also th e in vitro culture condition. Our observations may explain some of the cont radictions in the literature. Therefore, the data obtained with this line s hould be evaluated more carefully, considering morphological and functional characteristics of the possible variants in the cell population. However, this heterogeneity may represent a good model in the study of tumor progres sion.