Development and characterisation of novel human multidrug resistant mammary carcinoma lines in vitro and in vivo

✍ Scribed by Ulrike Stein; Wolfgang Walther; Margit Lemm; Helga Naundorf; Iduna Fichtner

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: French
• Weight: 127 KB
• Volume: 72
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/(sici)1097-0215(19970904)72:5<885::aid-ijc28>3.0.co;2-6

✦ Synopsis

Clinical chemotherapy of breast carcinomas must be considered insufficient, mainly due to the appearance of drug resistance. The multidrug resistance (MDR) phenotype, either intrinsically occurring or acquired, e.g., against a panel of different antineoplastic drugs, is discussed in relation to several MDR-associated genes such as the MDR-gene mdr1 encoding the P-glycoprotein (PGP), the MRP gene (multidrug resistance protein) encoding an MDR-related protein or the LRP gene encoding the lung resistance protein. Numerous experimental and clinical approaches aiming at reversing resistance require well-characterised in vitro and in vivo models. The aim of our work was to develop multidrug resistant sublines from human xenotransplanted breast carcinomas, in addition to the broadly used line MCF-7 and its multidrug resistant subline MCF-7/Adr R . MDR was induced in vitro with increasing concentrations of Adriablastin (ADR) for several weeks, resulting in a 3.5-to 35-fold increase in IC 50 values using the MTT-test. Cell lines were cross-resistant toward another MDR-related drug, vincristine, but remained sensitive to non-MDR-related compounds such as cisplatin and methotrexate. The resistance toward Adriamycin and vincristine was confirmed in vivo by a lack of tumour growth inhibition in the nude mouse system. Gene expression data for the mdr1/PGP, MRP/MRP and LRP/LRP on both the mRNA (RT-PCR) and the protein levels (immunoflow cytometry) demonstrated that induction of mdr1 gene expression was responsible for the acquired MDR phenotype. Rhodamine efflux data, indicated by PGP overexpression, underlined the development of this MDR mechanism in the newly established breast carcinoma lines MT-1/ADR, MT-3/ADR and MaTu/ADR.