Selective tumor targeting by the hypoxia-activated prodrug AQ4N blocks tumor growth and metastasis in preclinical models of pancreatic cancer.

Abstract

PURPOSE:

The antitumor activities and pharmacokinetics of the hypoxia-activated cytotoxin AQ4N and its metabolites were assessed in several preclinical models of pancreatic cancers.

EXPERIMENTAL DESIGN:

The cytotoxic effects of AQ4N prodrug and its bioreduced form, AQ4, were tested against multiple human tumor cell lines using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Nude mice bearing s.c. or orthotopically implanted human BxPC-3 or Panc-1 tumor cells were treated with AQ4N. Tumor growth inhibition, time to progression/end point, and liver metastasis were evaluated in treatment versus control groups. Plasma and tumor levels of AQ4N and its metabolites were quantitated by liquid chromatography-tandem mass spectrometry.

RESULTS:

In contrast to AQ4N, the bioreduced AQ4 metabolite displayed potent cytotoxicity in many human tumor lines, including those derived from human pancreatic adenocarcinomas. Single-agent administration of AQ4N significantly delayed tumor growth, progression, and survival in a manner comparable with gemcitabine in multiple pancreatic tumor models in vivo. Survival increases were accompanied by a reduction in incidence and spread of liver metastasis. Quantitation of AQ4N and its metabolites in tumor-bearing mice showed that the prodrug is rapidly cleared from the circulation by 24 h and neither of the bioreduced metabolites was detected in plasma. In contrast, AQ4N readily penetrated BxPC-3 tumors and the cytotoxic AQ4 metabolite rapidly accumulated in tumor tissues at high levels in a dose-dependent fashion.

CONCLUSION:

AQ4N undergoes rapid and selective conversion into the potent antineoplastic metabolite AQ4 in tumors in vivo and provides proof of principle for the use of hypoxia-activated prodrugs in the treatment against pancreatic cancers.

• Authors: Alshad S Lalani, Susan E Alters, Alvin Wong, Mark R Albertella, Jeffrey L Cleland, William David Henner
• Journal: Clinical cancer research : an official journal of the American Association for Cancer Research (Clin Cancer Res) Vol. 13 Issue 7 Pg. 2216-25 (Apr 01 2007) ISSN: 1078-0432 [Print] United States
• PMID: 17404106 (Publication Type: Journal Article)

Chemical References

• Anthraquinones
• Antineoplastic Agents
• Prodrugs
• AQ4N

Topics

• Animals
• Anthraquinones (metabolism, pharmacology)
• Antineoplastic Agents (metabolism, pharmacology)
• Cell Hypoxia (physiology)
• Cell Proliferation (drug effects)
• Disease Models, Animal
• Drug Delivery Systems
• Female
• Humans
• Mice
• Mice, Nude
• Neoplasm Metastasis (drug therapy)
• Pancreatic Neoplasms (drug therapy)
• Prodrugs (metabolism, pharmacology)