Induction of magnetic resonance-visible lipid in a transformed human breast cell line by tetraphenylphosphonium chloride

✍ Scribed by Sandrine K. Roman; Thomas M. Jeitner; Rebecca Hancock; Wendy A. Cooper; Darryl C. Rideout; Edward J. Delikatny

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: French
• Weight: 219 KB
• Volume: 73
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/(sici)1097-0215(19971114)73:4<570::aid-ijc19>3.0.co;2-d

✦ Synopsis

Proton magnetic resonance spectroscopy ( 1 H MRS) and DNA flow cytometry were used to monitor the effects of the cationic lipophilic phosphonium salt and potential antineoplastic agent tetraphenylphosphonium chloride (TPP) on the transformed human breast cell line HBL-100. TPP treatment for 48 hr was cytostatic at low concentrations and cytotoxic at higher concentrations with an IC 50 of 55 µM as measured by Trypan blue exclusion. At micromolar concentrations, TPP caused a significant increase in the methylene MR signal arising from mobile lipid as measured by the ratio of the lipid CH 2 peak height to either the CH 3 peak height (internal referencing) or the peak height for p-aminobenzoic acid (PABA) as an external reference in a co-axial capillary within the sample. Over the same concentration range, TPP caused a slowing of passage through S phase as demonstrated by a significant depletion of cells in G 2 /M phase with a concurrent but non-significant increase in cells in S. Time-dependent increases in MR-visible lipid were observed with 2 M TPP treatment, and the removal of TPP from the culture medium caused no significant reduction in mobile lipid. Two-dimensional 1 H} 1 H COSY spectra of TPP-treated HBL-100 cells revealed concentration-dependent increases in cross-peak volume ratios arising from lipid acyl chains relative to both internal (lysine, polyamines) and external (PABA) standards. Increases in choline and glycerophosphocholine cross-peak volume ratios were observed, indicating that the catabolism or rearrangement of phospholipids may be responsible for the observed MR-visible lipid increases.