Assessment of in vitro drug resistance of human breast cancer cells subcultured from biopsy specimens.
The low cellular yield of a breast cancer sample represents a limiting factor for in vitro chemosensitivity/chemoresistance testing. The use of in vitro serially cultured cells can help overcome this obstacle.


METHODS
In vitro drug resistance of cells cultured from mammary carcinomas by the 3T3 feeder-layer technique was tested by the MTT assay. Out of the 33 tested cultures, 9 were derived from cells obtained from true-cut biopsies of primary tumours, with sample volume less than 0.03 cm3. The cultures were treated with 6 anticancer drugs at 6-8 concentrations. The chemoresistance of cultured cells was monitored by the surviving cell fraction as a function of the drug concentration.


RESULTS
The average time to obtain a result was 28 days. The volume of an original sample had no effect on the in vitro resistance of a culture, suggesting minimal alteration of in vitro chemosensitivity of cells by their cultivation. Histopathological grade, estrogen receptor status or expression of the c-erb-B2 protein of the original tumours did not significantly correlate with the resistance of cultures. Individual drugs displayed distinct in vitro effectiveness. Paclitaxel and cisplatin were the most potent drugs. Gemcitabine, vinorelbine and mafosfamide were the least potent drugs. Doxorubicin and gemcitabine most frequently failed to completely metabolically inhibit 100% of cultured cells at any concentration.


CONCLUSIONS
Combination of the optimised feeder-layer cultivation technique and the MTT test permits extensive drug resistance testing from very small breast cancer samples.
Krasna
Luboslava
L
Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Department of Oncology, 1st Medical Faculty, Charles University, Prague, Czech Republic.
Netikova
Irena
I
Chaloupkova
Alena
A
Taislova
Eva
E
Zimovjanova
Martina
M
Vesely
Pavel
P
Danes
Jan
J
Petruzelka
Lubos
L
Matouskova
Eva
E
D016475:3T3 Cells; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001706:Biopsy; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D002470:Cell Survival / Q000187:drug effects; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D005240:Feasibility Studies; D006801:Humans; D051379:Mice; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D013778:Tetrazolium Salts; D013844:Thiazoles; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D013778:Tetrazolium Salts; D013844:Thiazoles; C022616:thiazolyl blue