title: Effect of hypoxia on the expression of phosphoglycerate kinase and antitumor activity of troxacitabine and gemcitabine in non-small cell lung carcinoma.
abstract: Beta-L-dioxolane-cytidine (L-OddC; BCH-4556; troxacitabine), a novel L-configuration deoxycytidine analogue, was under clinical trials for treating cancer. The cytotoxicity of L-OddC is dependent on its phosphorylation to L-OddCTP by phosphoglycerate kinase (PGK) and its subsequent addition into nuclear DNA. Because PGK is induced with hypoxia, the expression of hypoxia-inducible factor-1alpha and PGK of H460 cells (human non-small cell lung carcinoma) in vitro and in vivo was studied. In culture, hypoxic treatment induced the protein expression of PGK by 3-fold but had no effect on the protein expression of other L-OddC metabolism-associated enzymes such as apurinic/apyrimidinic endonuclease-1, deoxycytidine kinase, CMP kinase, and nM23 H1. Using a clonogenic assay, hypoxic treatment of H460 cells rendered cells 4-fold more susceptible to L-OddC but not to gemcitabine (dFdC) following exposure to drugs for one generation. Using hypoxia response element-luciferase reporter system, Western blotting, and immunohistochemistry, it was found that hypoxia-inducible factor-1alpha and PGK expression increased and could be correlated to tumor size. Despite dFdC being more toxic than L-OddC in cell culture, L-OddC (300 mg/kg i.p.) had a stronger antitumor activity than dFdC in H460 xenograft-bearing nude mice. Furthermore, L-OddC retained approximately 50% of its antitumor activity with oral gavage compared with i.p. delivery. Oral administration of L-OddC (600 mg/kg p.o.) had a similar area under the curve value compared with i.p. injection of dFdC (300 mg/kg i.p.). In conclusion, the hypoxia, which commonly exists in non-small cell lung carcinoma or other solid tumors resistant to radiotherapy or chemotherapy, is a favorable determinant to enhance the antitumor activity of L-OddC in vivo.
authors.affiliation: Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06510, USA.
authors.forename: Wing
authors.initials: W
authors.lastname: Lam
authors.forename: Scott
authors.initials: S
authors.lastname: Bussom
authors.forename: Yung-Chi
authors.initials: YC
authors.lastname: Cheng
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy* / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology; D016923:Cell Death / Q000187:drug effects; D015687:Cell Hypoxia / Q000187:drug effects; D045744:Cell Line, Tumor; D003596:Cytosine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use; D004148:Dioxolanes / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000378:metabolism; D010735:Phosphoglycerate Kinase / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements; D014158:Transcription, Genetic / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays; D000093542:Gemcitabine
chemical_list: D000970:Antineoplastic Agents; D004148:Dioxolanes; D009363:Neoplasm Proteins; D003841:Deoxycytidine; C074908:troxacitabine; D003596:Cytosine; D010735:Phosphoglycerate Kinase; D000093542:Gemcitabine