CG5/Dx human breast cancer cell line: characterization of a new doxorubicin-resistant variant
Gibelli, N.; Zibera, C.; Asti, A.; Maestri, L.; Bacchella, L.; Pedrazzoli, P.; Calligaro, A.; Robustelli della Cuna, G.
Anticancer Research 16(4a): 1675-1681
1996
ISSN/ISBN: 0250-7005 PMID: 8712686 Document Number: 464081
By continuous exposure of CG5 human breast cancer cell line to increasing doxorubicin (Dx) concentrations, a multidrug-resistant (MDR) subline (CG5/Dx) was obtained. The resistant variant showed P-glycoprotein (P-gp) expression and a lower intracellular doxorubicin level than the parental cells. CG5/Dx cells were 19.4 fold more resistant to Dx than CG5 cells and showed a cross-resistance to some structurally related and unrelated compounds. Differences in kinetics, biological and ultrastructural features between the two cell lines were investigated. The CG5/Dx cells grew more slowly, produced higher CEA levels and showed a reduced progesterone receptor (PgR) content than the parental cells. Ultrastructural studies revealed differences involving, polyribosomes, rough endoplasmic reticulum, and cytoskeleton.