Influence of clodronate on breast cancer cells in vitro.
One of the major therapies of bone metastasis is administration of clodronate. But the influence of clodronate alone on tumour cells is not quite clear. Radiotherapy and administration of clodronate increasingly are used in combination. The influence of clodronate on radiosensitivity of tumour cells is not known.


METHODS
We used MDA-MB-435S and MCF-7 cells (breast cancer) in vitro and exposed the cells to clodronate in different concentrations and different short application times. In a second experiment we added graded doses of radiotherapy to the cell cultures. All experiments were done under standard conditions of the colony test.


RESULTS
At different concentrations and different incubation times clodronate is able to reduce the cell survival of MDA-MB-435S cells, but not of MCF-7 cells. Even very low concentrations of clodronate in the cell culture medium are sufficient to reduce the tumour cell survival of MDA-MB-435S down to 59%. This reduction is time and concentration dependent. Using irradiation, clodronate has definitively no influence on the radiosensitivity of MDA-MB-435S cells in vitro, but the shoulder of the survival curve of MCF-7 cells is markedly reduced, demonstrating reduced repair of sublethal radiation damage.
Busch
M
M
Klinik und Poliklinik für Strahlentherapie und Radioonkologie, Ludwig-Maximilians-University München, Klinikum Grosshadern, Marchioninistr. 15, D-81377 München, Germany. busch@radonc.med.uni-muenchen.de
Rave-Fränk
M
M
Hille
A
A
Dühmke
E
E
D000368:Aged; D001943:Breast Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000532:radiotherapy; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004002:Clodronic Acid / Q000494:pharmacology* / Q000627:therapeutic use; D003131:Combined Modality Therapy; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D014407:Tumor Cells, Cultured
D004002:Clodronic Acid