title: Creatine and cyclocreatine treatment of human colon adenocarcinoma xenografts: 31P and 1H magnetic resonance spectroscopic studies.
abstract: Creatine (Cr) and cyclocreatine (cyCr) have been shown to inhibit the growth of a variety of human and murine tumours. The purpose of this study was to evaluate the anti-tumour effect of these molecules in relation to drug accumulation, energy metabolism, tumour water accumulation and toxicity. Nude mice carrying a human colon adenocarcinoma (LS174T) with a creatine kinase (CK) activity of 2.12 units mg(-1) protein were fed Cr (2.5% or 5%) or cyCr (0.025%, 0.1% or 0.5%) for 2 weeks and compared with controls fed standard diet. Cr concentrations of 2.5% and 5% significantly inhibited tumour growth, as did 0.1% and 0.5% cyCr. In vivo 31P magnetic resonance spectroscopy (MRS) after 2 weeks of treatment showed an increase in [phosphocreatine (PCr)+phosphocyclocreatine (PcyCr)]/nucleoside triphosphate (NTP) with increasing concentrations of dietary Cr and cyCr, without changes in absolute NTP contents. The antiproliferative effect of the substrates of CK was not related to energy deficiency but was associated with acidosis. Intratumoral substrate concentrations (measured by 1H-MRS) of 4.8 micromol g(-1) wet weight Cr (mice fed 2.5% Cr) and 6.2 micromol g(-1) cyCr (mice fed 0.1% cyCr) induced a similar decrease in growth rate, indicating that both substrates were equally potent in tumour growth inhibition. The best correlant of growth inhibition was the total Cr or (cyCr+Cr) concentrations in the tissue. In vivo, these agents did not induce excessive water accumulation and had no systemic effects on the mice (weight loss, hypoglycaemia) that may have caused growth inhibition.
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Kristensen
authors.forename: N
authors.initials: N
authors.lastname: Askenasy
authors.forename: R K
authors.initials: RK
authors.lastname: Jain
authors.forename: A P
authors.initials: AP
authors.lastname: Koretsky
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism* / Q000494:pharmacology; D001834:Body Water; D002455:Cell Division / Q000187:drug effects; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology; D003401:Creatine / Q000378:metabolism* / Q000494:pharmacology; D003402:Creatine Kinase / Q000378:metabolism; D003404:Creatinine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051379:Mice; D008819:Mice, Nude; D010758:Phosphorus; D010766:Phosphorylation; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D010758:Phosphorus; C012260:cyclocreatine; D006859:Hydrogen; D003404:Creatinine; D003402:Creatine Kinase; D003401:Creatine