2-(2-nitro-1h-imidazol-1-yl)-n-(2-2-3-3-3-pentafluoropropyl)acetamide and Sarcoma

The presence of hypoxia, measured by needle electrodes, has been shown to be associated with poor patient outcome in several human tumor types, including soft tissue sarcomas. The present report emphasizes the evaluation of hypoxia in soft tissue sarcomas based upon the binding of the 2-nitroimidazole drug EF5 (2-[2-nitro-1H-imidazol-1-yl]-N-(2,2,3,3,3-pentafluoropropyl) acetamide). EF5 has previously been shown to be predictive of radiation response in animal tumors and in in vitro studies. We have also previously reported studies of EF5 binding in human squamous cell tumors. Using fluorescent immunohistochemical techniques, we provide data on the presence and distribution of EF5 binding, as a surrogate for hypoxia, in human spindle cell tumors.. Patients with spindle cell tumors who were scheduled for tumor surgery were asked to participate in the Phase I trial of EF5. Approximately 48 h preoperatively, EF5 was administered i.v. at doses between 9 and 21 mg/kg. Binding in frozen sections of biopsied tissues was determined using monoclonal antibodies labeled with the green-excited, orange-emitting fluorescent dye, Cy3. Calibration studies were performed in vitro by incubating fresh tumor tissue cubes obtained from each patient with EF3 (an analog of EF5) under hypoxic conditions ("reference binding"). The goal of these calibration studies was to quantify the maximal binding levels possible in individual patient's tissues. The relationship between binding (in situ based on EF5 binding) and reference binding (in vitro based on EF3 binding) was determined.. Eight patients were studied; 3 of these patients had gastrointestinal stromal tumors (GIST). The incubation of tumor tissue cubes in EF3 under hypoxic conditions demonstrated that all tumors bound drug to a similar extent. Reference binding showed a 3.2-fold variation in median fluorescence (113-356) on an absolute fluorescence scale, calibrated by a Cy3 dye standard. In situ binding in the brightest tumor section varied by a factor of 25.4 between the lowest and highest binding tumor (7.5-190.2). Heterogeneity of highest binding was greater between tumors than within individual tumors. A correspondence between EF5 binding and Eppendorf needle electrode studies was seen in the 5 patients with non-GISTs.. Inter- and intratumoral heterogeneity of EF5 binding in spindle cell tumors has been documented. Patterns of binding consistent with diffusion limited hypoxia are present in human spindle cell neoplasms.

Topics: Adult; Aged; Cell Hypoxia; Etanidazole; Extremities; Female; Gastrointestinal Neoplasms; Humans; Hydrocarbons, Fluorinated; Immunohistochemistry; Indicators and Reagents; Male; Middle Aged; Radiation-Sensitizing Agents; Sarcoma

To study the 2-nitroimidazole agent EF5 as a surrogate for measuring hypoxia in a series of patients with soft tissue sarcomas, and to determine whether hypoxia measured with this technique was associated with patient outcome.. Patients with soft tissue sarcomas of the head and neck, extremity, trunk, or retroperitoneum for whom surgical excision was the initial treatment of choice, were given 21 mg/kg EF5 24-48 hours before surgery. Biopsy specimens were stained for EF5 binding with fluorescence-labeled monoclonal antibodies, and the images were analyzed quantitatively. Endpoints included the relationship between EF5 binding, clinically important prognostic factors, and patient outcome.. Two patients with recurrent and 14 patients with de novo sarcomas were studied. There were seven low-grade, one intermediate-grade, and eight high-grade tumors. No relationship was found between EF5 binding and patient age, sex, hemoglobin level, or tumor size. In de novo tumors, the presence of mitoses and histologic grade were positively correlated with hypoxia. High-grade and -stage de novo tumors had higher levels of EF5 binding compared with low-grade and -stage tumors. Patients with de novo tumors containing moderate to severe hypoxia (> or = 20% EF5 binding), high grade, or > or = 7% mitoses were more likely to develop metastases.. Further studies in a larger cohort of patients are necessary to determine whether hypoxia, as measured by EF5 binding, is an independent prognostic factor for outcome in high-grade sarcomas. Such data should be useful to identify high-risk patients for clinical trials to determine whether early chemotherapy will influence the occurrence of metastasis.

Topics: Adult; Aged; Cell Hypoxia; Etanidazole; Female; Humans; Hydrocarbons, Fluorinated; Indicators and Reagents; Male; Middle Aged; Neoplasm Recurrence, Local; Sarcoma; Survival Analysis; Treatment Outcome

Response to photodynamic therapy depends on adequate tumor oxygenation as well as sufficient accumulation of photosensitizer in the tumor. The goal of this study was to investigate the presence of hypoxia and retention of the photosensitizer Photofrin in the tumors of patients with intra-abdominal carcinomatosis or sarcomatosis.. Tumor nodules from 10 patients were studied. In nine of these patients, hypoxia was identified in histological sections of biopsied tumor after administration of the hypoxia marker 2-(2-nitroimidazol-1[H]-yl)-N-(2,2,3,3,3-pentafluoropropyl)acetamide (EF5). In separate tumor nodules from 10 patients, Photofrin uptake was measured by fluorescence after tissue solubilization.. Hypoxia existed in the tumors of five patients, with three of these patients demonstrating at least one severely hypoxic nodule. Physiological levels of oxygen were present in the tumors of four patients. An association between tumor size and hypoxia was not evident because some tumor nodules as small as approximately 2 mm in diameter were severely hypoxic. However, even these tumor nodules contained vascular networks. Three patients with severely hypoxic tumor nodules exhibited moderate levels of Photofrin uptake of 3.9 +/- 0.4 to 3.9 +/- 0.5 ng/mg (mean +/- SE). The four patients with tumors of physiological oxygenation did not consistently exhibit high tumor concentrations of Photofrin: mean +/- SE drug uptake among these patients ranged from 0.6 +/- 0.8 to 5.8 +/- 0.5 ng/mg.. Carcinomatosis or sarcomatosis of the i.p. cavity may exhibit severe tumor hypoxia. Photofrin accumulation in tumors varied by a factor of approximately 10x among all patients, and, on average, those with severe hypoxia in at least one nodule did not demonstrate poor Photofrin uptake in separate tumor samples. These data emphasize the need for reconsideration of the generally accepted paradigm of small tumor size, good oxygenation, and good drug delivery because this may vary on an individual tumor basis.

Topics: Appendiceal Neoplasms; Benzimidazoles; Binding, Competitive; Carbocyanines; Colonic Neoplasms; Dihematoporphyrin Ether; Etanidazole; Female; Gastrointestinal Neoplasms; Gastrointestinal Stromal Tumors; Humans; Hydrocarbons, Fluorinated; In Vitro Techniques; Intestine, Small; Male; Microscopy, Fluorescence; Ovarian Neoplasms; Oxygen; Photochemotherapy; Sarcoma

The present studies were undertaken to determine whether 19F MRS could be used to quantify the binding of the pentafluorinated derivative of etanidazole (EF5) in hypoxic cells of solid tumors.. A 4.7 T imaging magnet was used for the in situ and in vitro evaluation of EF5 signals. In order to develop a better understanding of these NMR measurements the characteristics of parent, reduced unbound, and reduced bound EF5 signals were examined in vitro using a 12 T spectrometer.. In situ data acquired using a 4.7 T imaging magnet, showed retention of EF5 signals in KHT sarcomas that was absent in muscles for 6 h after EF5 injection. In vitro studies showed no difference in the NMR detectable signal of parent and reduced unbound EF5. T2 values determined using parent EF5 samples revealed a T2 time of 675 ms. In contrast, EF5 bound to KHT tumor cells gave rise to signals of low intensity, broad line widths, and T2 relaxation times of less than 30 ms. When the same samples were analyzed using the 4.7 T imaging magnet, the CF3 and CF2 fluorine peaks were readily identifiable in the parent EF5 sample but no fluorine signal could be detected from EF5 bound to KHT tumor cells.. The inability to resolve bound EF5 metabolites even at high field strengths (12 T), coupled with the short T2 relaxation times of the bound EF5, and the limits of detection of the in situ applied imaging magnet (4.7 T), meant that hypoxic cells could not be quantified in tumors using the 19F MRS technique. In situ 19F MRS measurements of EF5 signals (parent/reduced unbound) may reflect conditions of tumor physiology and thus indicate the extent of tumor hypoxia but they are not capable of resolving the cellular oxygenation status of the tumor cells.

Topics: Animals; Antineoplastic Agents; Biomarkers; Cell Hypoxia; Etanidazole; Female; Fluorine Radioisotopes; Hydrocarbons, Fluorinated; Magnetic Resonance Spectroscopy; Mice; Radionuclide Imaging; Sarcoma