2-(2-nitro-1h-imidazol-1-yl)-n-(2-2-3-3-3-pentafluoropropyl)acetamide and Carcinoma--Squamous-Cell

Localization and quantitation of 2-nitroimidazole drug binding in low pO2 tumors is a technique that can allow the assessment of hypoxia as a predictive assay. EF5 [2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl) acetamide] is such a drug, and it has been shown to be predictive of radiation response in rodent tumors. Using fluorescence immunohistochemical techniques, we provide data on the presence, distribution, and levels of EF5 binding as a surrogate for hypoxia in human head and neck and uterine cervix squamous cell cancers (SCCs). Six patients with SCC were studied. Four patients had head and neck tumors, and two had uterine cervix cancers. The incubation of fresh tissue cubes in EF3 under hypoxic conditions ("reference binding") demonstrated that all tumors were capable of binding drug, and that this binding varied by a factor of 2.9-fold (174.5-516.1) on an absolute fluorescence scale. In the five patients treated at the lowest drug doses (9 mg/kg), in situ binding was quantitatable. For all six patients, the maximum rate of in situ binding varied by a factor of 6.7 between the lowest and highest binding tumor (24.8-160.3) on an absolute fluorescence scale. In tumors with high binding regions, intratumoral heterogeneity was large, extending from minimal fluorescence (<1%) up to 88.6% of reference binding. In tumors with minimal binding, there was little intratumoral heterogeneity. These studies demonstrate substantial heterogeneity of in situ binding between and within individual squamous cell tumors.

Topics: Adult; Aged; Antineoplastic Agents; Binding Sites; Carcinoma, Squamous Cell; Cell Hypoxia; Etanidazole; Female; Head and Neck Neoplasms; Humans; Hydrocarbons, Fluorinated; Male; Middle Aged; Uterine Cervical Neoplasms

Topics: Antigens, Neoplasm; Biomarkers; Carbonic Anhydrase IX; Carbonic Anhydrases; Carcinoma, Squamous Cell; Cell Hypoxia; Electrodes; Etanidazole; Head and Neck Neoplasms; Humans; Hydrocarbons, Fluorinated; Intracellular Signaling Peptides and Proteins; Mitochondrial Proteins; Neoplasm Proteins; Nitroimidazoles; Osteopontin; Oxygen; Partial Pressure; Radiation-Sensitizing Agents; Tirapazamine; Triazines

EF5, a 2-nitroimidazole hypoxia marker, was used to study the presence, levels, and prognostic significance of hypoxia in primary head and neck squamous cell tumors.. Twenty-two patients with newly diagnosed squamous cell carcinoma of the oral cavity, oropharynx, or larynx with at least 2 years of clinical follow-up were included in this study. Quantitative analyses of EF5 immunofluorescence was carried out, and these data were compared with patient outcome.. EF5 immunostaining showed substantial intra- and intertumoral hypoxic heterogeneity. The majority of cells in all tumors were well oxygenated. Three patterns of EF5 binding in cells were identified using criteria based on the cellular region that was stained (peripheral or central) and the relationship of binding to necrosis. We tested the association between EF5-binding levels with event-free and overall survival irrespective of the pattern of cellular binding or treatment regimen. Patients with tumors containing EF5-binding regions corresponding to severe hypoxia (< or =0.1% oxygen) had a shorter event-free survival time than patients with pO(2) values greater than 0.1% (p = 0.032). Nodal status was also predictive for outcome.. These data illustrate the potential utility of EF5 binding based on quantitative immunohistochemistry of tissue pO(2) and provide support for the development of noninvasive hypoxia positron emission tomographic studies with fluorine 18-labeled EF5.

Topics: Aged; Carcinoma, Squamous Cell; Cell Hypoxia; Etanidazole; Female; Fluorescent Antibody Technique; Head and Neck Neoplasms; Humans; Hydrocarbons, Fluorinated; Indicators and Reagents; Laryngeal Neoplasms; Male; Middle Aged; Mouth Neoplasms; Oropharyngeal Neoplasms; Prospective Studies

The hypoxia-inducible factor 1 (HIF-1) is known to induce the expression of several proteins linked to the maintenance of oxygen homeostasis, cellular energy metabolism, and tumor progression. Its alpha subunit (HIF-1alpha) is stabilized under hypoxic conditions and, therefore, might represent an intrinsic marker for tissue hypoxia. Here we report on the spatial relationship between HIF-1alpha and the nitroimidazole hypoxia marker EF5 in cervical carcinoma xenografts, and on their spatial relationship to tumor blood vessels. EF5 was administered to mice bearing ME180 and SiHa cervical cancer xenografts. Frozen tumor tissue sections, triple-stained for HIF-1alpha, the endothelial cell marker CD31, and EF5, were imaged using wide-field multiparameter immunofluorescence microscopy. Expression levels of EF5 and HIF-1alpha were similar in ME180 xenografts, but the percentage of tumor area stained with EF5 was significantly smaller than the percentage of HIF-1alpha-positive area in SiHa tumors. In both tumor types the EF5-HIF-1alpha overlap was statistically significant, thus confirming their spatial and temporal colocalization. Spatial distribution analysis of EF5 and HIF-1alpha is consistent with different pO2 value "thresholds" for EF5 binding and HIF-1alpha expression. Summarized, our results indicate that HIF-1alpha is a useful intrinsic marker for hypoxia in cervical carcinoma xenografts.

Topics: Animals; Biomarkers, Tumor; Carcinoma, Squamous Cell; Cell Hypoxia; Etanidazole; Female; Humans; Hydrocarbons, Fluorinated; Mice; Mice, SCID; Microscopy, Fluorescence; Neoplasm Transplantation; Transplantation, Heterologous; Uterine Cervical Neoplasms