title: Stability, accumulation and cytotoxicity of an albumin-cisplatin adduct.
abstract: The accumulation and cytotoxicity of a 10 μmol L⁻¹ equimolar human serum albumin-cisplatin adduct (HSA-Pt) was investigated in suspension Ehrlich Ascites Tumor Cells (EATC) and adherent Ehrlich Lettré Ascites Cells (Lettré). HSA-Pt did not induce apoptosis nor was it taken up by the cells to any significant amount within 24 h incubation. The accumulation and cytotoxicity of HSA-Pt was compared to 10 μmol L⁻¹ cisplatin for which a larger accumulation and cytotoxicity were observed in EATC compared to Lettré. The experiment was performed with cell medium exchange every fourth hour as HSA-Pt and cisplatin were not stable in RPMI-1640 with 10% serum. The stability was determined using size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS) and after 4 h new platinum peaks were observed. These findings indicate that before conducting cell experiments, the stability of the compound in the cell medium should be investigated especially when long exposure times are applied. Furthermore, HSA-Pt was found to be stable in Hanks Balanced Saline Solution (HBSS) and in Phosphate Buffered Saline (PBS) at pH 5.3, 6.1 and 7.4. Thus, the shift in pH when HSA-cisplatin passes from blood (pH 7.4) to tumor tissue (pH 5-6) is not capable of releasing cisplatin from HSA.
authors.affiliation: Department of Pharmaceutics and Analytical Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetspark 2, DK-2100 Copenhagen East, Denmark. cmoe@farma.ku.dk
authors.forename: Charlotte
authors.initials: C
authors.lastname: Møller
authors.forename: Hanne Sørup
authors.initials: HS
authors.lastname: Tastesen
authors.forename: Bente
authors.initials: B
authors.lastname: Gammelgaard
authors.forename: Ian Henry
authors.initials: IH
authors.lastname: Lambert
authors.forename: Stefan
authors.initials: S
authors.lastname: Stürup
mesh_terms: D045744:Cell Line, Tumor; D002945:Cisplatin / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D003603:Cytotoxins / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D006801:Humans; D008667:Metalloproteins / Q000378:metabolism / Q000633:toxicity; D010984:Platinum / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*
chemical_list: D003603:Cytotoxins; D008667:Metalloproteins; D012709:Serum Albumin; D010984:Platinum; D002945:Cisplatin