title: Pinpointing differences in cisplatin-induced apoptosis in adherent and non-adherent cancer cells.
abstract: Platinum compounds are used in the treatment of cancer. We demonstrate that cisplatin-induced (10 μM) apoptosis (caspase-3 activity) is pronounced within 18 hours in non-adherent Ehrlich ascites tumour cells (EATC), whereas there is no increase in caspase-3 activity in the adherent Ehrlich Lettré ascites tumour cells (ELA). Loss of KCl and cell shrinkage are hallmarks in apoptosis and has been shown in EATC. However, we find no reduction in cell volume and only a minor loss of K(+) which is accompanied by net uptake of Na(+) following 18 hours cisplatin exposure in ELA. Glutathione and taurine have previously been demonstrated to protect cells from apoptosis. We find, however, that increase or decrease in the cellular content of glutathione and taurine has no effect on cisplatin-induced cell death in EATC and ELA. Nevertheless, knock-down of the taurine transporter TauT leads to a significant increase in apoptosis in ELA following cisplatin exposure. We find that cytosolic accumulation of cisplatin is similar in EATC and ELA. However, the nuclear accumulation and DNA-binding of cisplatin is significant lower in ELA compared to EATC. We suggest three putative reasons for the observed cisplatin insensitivity in the adherent tumor cells (ELA) compared to the non-adherent tumor cells (EATC): less nuclear cisplatin accumulation, increased TauT activity, and decreased anion and water loss.
authors.affiliation: Department of Biology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Hanne Sørup
authors.initials: HS
authors.lastname: Tastesen
authors.forename: Jacob Bak
authors.initials: JB
authors.lastname: Holm
authors.forename: Jacob
authors.initials: J
authors.lastname: Møller
authors.forename: Kristian Arild
authors.initials: KA
authors.lastname: Poulsen
authors.forename: Charlotte
authors.initials: C
authors.lastname: Møller
authors.forename: Stefan
authors.initials: S
authors.lastname: Stürup
authors.forename: Else Kay
authors.initials: EK
authors.lastname: Hoffmann
authors.forename: Ian Henry
authors.initials: IH
authors.lastname: Lambert
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000633:toxicity*; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D048429:Cell Size / Q000187:drug effects; D002945:Cisplatin / Q000633:toxicity*; D019008:Drug Resistance, Neoplasm; D055785:Gene Knockdown Techniques; D005978:Glutathione / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D035683:MicroRNAs / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D013654:Taurine / Q000378:metabolism; D014407:Tumor Cells, Cultured; D000099247:Taurine Transporters
chemical_list: D000970:Antineoplastic Agents; D053148:Caspase 3; D002945:Cisplatin; D005978:Glutathione; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D035683:MicroRNAs; D011188:Potassium; D013654:Taurine; D000099247:Taurine Transporters