A Novel Alkylating Agent, Glufosfamide, Enhances the Activity of Gemcitabine In Vitro, In Vivo

Abstract

Glufosfamide is an alkylating agent consisting of iphosphoramide mustard conjugated to glucose that is currently included in clinical studies of pancreatic cancer. We studied the effects of glufosfamide, in combination with gemcitabine, on in vitro, in vivo models of pancreatic cancer. In proliferation assays, glufosfamide, gemcitabine inhibited the growth of MiaPaCa- 2, H766t, PANC-1 cells, but the combination of the two agents provided greater effects. Apoptosis of MiaPaCa-2 cells, measured by fluorescence-activated cell sorting, was enhanced by the combination of the two drugs, compared to single-agent treatment. Glufosfamide alone inhibited the growth of red fluorescent proteinexpressing MiaPaCa-2 tumors in an orthotopic nude mouse model in a dose-dependent manner. Combining glufosfamide (30 mg/kg) with gemcitabine resulted in enhanced inhibition of tumor growth, significantly prolonged survival. Immunohistochemistry of excised tumors revealed that both glufosfamide, gemcitabine increased levels of apoptosis (measured by terminal deoxynucleotidyl transferase-mediated nick end labeling staining), reduced proliferation (measured by proliferating cell nuclear antigen staining). No effects on microvessel density were observed. These results support the use of the alkylating agent glufosfamide, the DNA synthesis inhibitor gemcitabine, rather than the use of either agent alone, to provide greater benefits, demonstrate that this combination treatment should be useful in the clinical treatment of pancreatic carcinoma.

Keywords

• Glufosfamide
• gemcitabine
• pancreatic cancer
• orthotopic model
• alkylating agent