Zoledronic acid induces micronuclei formation, mitochondrial-mediated apoptosis and cytostasis in kidney cells.

AIMS: Zoledronic acid (ZA), a FDA approved drug has used widely in the treatment of bone metastasis complications, has been linked to renal toxicity with unclear mechanism. The present study is aimed at investigating the genotoxic and cytotoxic effects of ZA in renal epithelial cells. MAIN METHODS: The genotoxic effect of ZA in Vero and MDCK cells determined by cytokinesis block micronucleus (CBMN) assay. The cytotoxic effect assessed by analysing cell cycle profile, cell death and mitochondrial membrane potential by flow cytometry using propidium iodide, AnnexinV-FITC/PI and JC1 dye staining, respectively, BAX and Bcl-2 expression by Western blotting and caspase activity by spectrofluorimetry. KEY FINDINGS: The cytotoxic effect of ZA based on MTT assay revealed variable sensitivities of Vero and MDCK cells, with IC50 values of 7.41 and 109.58 µM, respectively. The CBMN assay has shown prominent dose-dependent (IC10-50) induction of micronuclei formation in both cells, indicating ZA's clastogenic and aneugenic potential. Further, the ZA treatment led the cells to apoptosis, evident from dose-dependent increase in the percentage of cells in subG1 phase and display of membranous phosphatidylserine translocation. Studies also confirmed apoptosis through mitochondria, evident from the prominent increase in BAX/Bcl-2 ratio, mitochondrial membrane depolarization and caspase-3/7 activity. In addition, ZA reduces cytokinetic activity of renal cells, evident from dose-wise lowered replicative indices. SIGNIFICANCE: The study depict ZA's potential genotoxic effect along with cytotoxic effect in renal epithelial cells, could be key factors for the development of renal complications associated with it, which prompts renal safety measures in lieu with ZA usage.

Dehydrocostus lactone induces prominent apoptosis in kidney distal tubular epithelial cells and interstitial fibroblasts along with cell cycle arrest in ovarian epithelial cells.

Dehydrocostus lactone (DHCL), a sesquiterpene lactone is well-known for its antiulcer, anti-hepatotoxic and anticancer activity. However, the studies concerning the safety/toxicity potential of DHCL toward the cells of normal origin remain unclear. The present study is aimed at investigating the toxicity potential of DHCL in renal distal tubular and interstitial fibroblast cell lines (MDCK and NRK-49F cells, respectively), and also in ovarian epithelial cell line (CHO cells). The MTT assay has predicted potential cytotoxic activity of DHCL against the cell line types with IC50 values of 0.99, 2.1 and 5.15??M, respectively. The prominent dose-dependent (IC30,50 & 70) increase in the percentage of cells at subG1 phase in all the cell lines revealed apoptosis induction, further establishing the cytotoxic effect of DHCL. The DHCL exposure (4?h) revealed the induction of ROS in both renal cell lines, which is responsible for apoptosis induction. The NRK-49F cells displayed dose-wise (IC30-70) increase in chromatin condensation and membranous phosphatidylserine translocation further confirming apoptotic cell death. Also, their increase in BAX/Bcl-2 ratio, mitochondrial membrane permeability and caspase-3/7 activity establishes mitochondrial mediated apoptosis. In case of CHO cells, the higher percentage of cells at G2/M phase and expression of Cyclin B1 at lower concentration of DHCL (?IC30), indicate mitotic arrest. The incidence of chromatid gaps and negligible micronuclei formation in treated cells (IC10-30) suggest that sub-lethal concentrations of DHCL exposure causes mitotic arrest in response to the damages by steady expression of Cyclin B1. Under in vitro condition, the study of DHCL's potential cytotoxic effect on both kidney cells and ovarian epithelial cells indicated the possibility of adverse effects on normal healthy cells as well. Hence, the study recommends in-depth investigations on DHCL usage concerning its safety in therapeutic applications.

Costunolide induces micronuclei formation, chromosomal aberrations, cytostasis, and mitochondrial-mediated apoptosis in Chinese hamster ovary cells.

Costunolide (CE) is a sesquiterpene lactone well-known for its antihepatotoxic, antiulcer, and anticancer activities. The present study focused on the evaluation of the cytogenetic toxicity and cellular death-inducing potential of CE in CHO cells, an epithelial cell line derived from normal ovary cells of Chinese hamster. The cytotoxic effect denoting MTT assay has shown an IC50 value of 7.56 µM CE, where 50% proliferation inhibition occurs. The oxidative stress caused by CE was confirmed based on GSH depletion induced cell death, conspicuously absent in N-acetylcysteine (GSH precursor) pretreated cells. The evaluation of genotoxic effects of CE using cytokinesis block micronucleus assay and chromosomal aberration test has shown prominent induction of binucleated micronucleated cells and aberrant metaphases bearing chromatid and chromosomal breaks, indicating CE's clastogenic and aneugenic potential. The apoptotic death in CE treated cells was confirmed by an increase in the number of cells in subG1 phase, exhibiting chromatin condensation and membranous phosphatidylserine translocation. The apoptosis induction follows mitochondrial mediation, evident from an increase in the BAX/Bcl-2 ratio, caspase-3/7 activity, and mitochondrial membrane permeability. CE also induces cytostasis in addition to apoptosis, substantiated by the reduced cytokinetic (replicative indices) and mitotic (mitotic indices and histone H3 Ser-10 phosphorylation) activities. Overall, the cellular GSH depletion and potential genotoxic effects by CE led the CHO cells to commit apoptosis and lowered cell division. The observed sensitivity of CHO cells doubts unintended adverse effects of CE on normal healthy cells, suggesting higher essentiality of further studies in order to establish its safety efficacy in therapeutic explorations.