[Decrease in toxicity and therapeutic effect of zoledronic acid in combination therapy with different antioxidant extracts]

Abstract

Background: Zoledronic acid is used in the treatment of cancer-related diseases, although its use has been associated with avascular osteonecrosis.

Aims: To determine the possible protective effect of a range of antioxidant substances against the inhibition of human prostate epithelial cell growth (PNT2) and transgenic adenocarcinoma mouse prostate tumour cells (TRAMP-C1), in treatments combining zoledronic acid and ionising radiation (IR).

Material and method: Cell survival is studied via cell viability assays (MTT) for 2 cell lines in isolated and combined treatments with zoledronic acid and/or IR, as well as the effect of adding 3 antioxidant substances.

Results: Zoledronic acid displays a significant cytotoxic effect over PNT2 and TRAMP-C1 cells (P<.001). The administration of antioxidants together with the zoledronic acid shows a protective effect for normal prostate cells, yet not so for prostate tumour cells. However, the administration of rosmarinic acid and apigenin in treatments combined with zoledronic acid provides a protective effect from the harmful effects of applying ionizing radiation, not only for normal PNT2 cells, but also for tumour cells.

Conclusion: The use of antioxidant substances decreases the cytotoxic effect of zoledronic acid over non-tumour cells, and as such could be used in benign diseases. Furthermore, in the combined treatment using ionising radiation, these antioxidants also produced a protective effect in tumour cells, thus reducing the therapeutic effect sought by combining the treatment with radiation.

Keywords: Efectos de la radiación; Effects of radiation; Radio-protective; Radio-sensitising; Radioprotectores; Radiosensibilizantes; Zoledronic acid; Ácido zoledrónico.