Anomalous patterns of nitroimidazole binding adjacent to necrosis in human glioma xenografts: possible role of decreased oxygen consumption

Parliament, M.B.; Franko, Allan J.; Allalunis-Turner, M. J.; Mielke, BW; Santos, C; Wolokoff, BG; Mercer, JR

doi:10.1038/bjc.1997.52

Cited by 37 publications

(54 citation statements)

References 30 publications

(25 reference statements)

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“…and exhibited patterns of labelling with [H]misonidazole that were similar to those of xenografted tumours (Parliament et al 1997). Within the same flask.…”

Section: Resultsmentioning

confidence: 67%

“…Thus. although in several cases spheroids that were initiated from the same passage showed a restricted range of grain density over the innermost cells (Figure 3 and Table 1 (Parliament et al 1997). As the mechanism by which this diversity arises is unknown.…”

Section: Resultsmentioning

confidence: 95%

“…we examined the microregional distribution of a similar hypoxia marker ['H]misonidazole. in subcutaneous xenografts of several human glioma cell lines (Parliament et al 1997). Ex-idence for severe hypoxia adjacent to necrosis A-as found consistentlx in MOlOb tumours.…”

mentioning

confidence: 74%

“…The tumours were fixed in formalin and the distribution of misonidazole binding was assessed usinr autoradiography as described above for spheroids. Procedures specific to the xenografts have been described recently (Parliament et al 1997). …”

Section: Autoradiographymentioning

confidence: 99%

“…We proposed an interpretation of the variable presence of hypoxia in some xenografted glioma lines (Parliament et al 1997).…”

mentioning

confidence: 99%

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Variable presence of hypoxia in M006 human glioma spheroids and in spheroids and xenografts of clonally derived sublines

Franko¹,

Parliament²,

Allalunis-Turner³

et al. 1998

Br J Cancer

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Summary Recently we reported the variable presence of hypoxia adjacent to necrosis in human glioma lines grown as subcutaneous tumours in severe combined immunodeficient (SCID) mice. To assess the basis for this observation. we examined the pattem of oxygenation in M006 and M006XLo glioma spheroids. We found a wide range of binding of [3H] aExduding two spheroids with a mixture of high and low grains ( Figure 3B).completely at each feeding. The number of spheroids w-as reduced at each feeding to stabilize the rate of consumption of nutrients. The first spheroids reached diameters of 0.8-1.2 mm. at x-hich they w-ere eliaible for experiments. w ithin 4-5 eeks. M006XLo sublineIn an effort to denrve a subline that w-as adapted to grow-th at lowambient oxy gen. the M006XLo subline x as established from small M006 spheroids that had been exposed continuously to 0.6%7 oxygen for 13 days. beainning 1 week after initiation in air. The spheroids were disaggregated wxith 0.25%c trypsin. and the cells w ere groxx n in monolayer culture for four passages (5 w eeks). then injected subcutaneously in SCID mice. A tumour x-as disaggregated to yield a new line designated M006XLo. w hich w as propagated in monolayer culture. Cells from the third passage were stored in liquid nitrogen. and each line x-as discarded after 3 months in culture and replaced from frozen stock.Clonally derived sublines (Franko et al. 1987). The desired oxygen level was obtained by a series of partial evacuations. each of which was followed by refilling of the chambers with 95% nitroaenlr5% carbon dioxide. Metabolic actixation of misonidazole during the degrassing procedure w-as minimized by precooling the medium and the chambers to 0°C and maintainingr this temperature during, the 30-to 40-min degassing process. The incubation period was 3 h for the spinner flask. and an additional 30 min for the aluminum chambers. w-hich is the time required for the medium in the dishes to return to 37' in the cabinet used for incubation. The oxygen tension in each chamber was measured at the end of the incubation period. as described previously (Franko et al. 1987). AutoradiographyThe spheroids were fixed in formalin and embedded in wax. and 4-gm serial sections w-ere taken throughout the spheroids. Slides w-ith sections near the centres of the majority of the spheroids were

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“…and exhibited patterns of labelling with [H]misonidazole that were similar to those of xenografted tumours (Parliament et al 1997). Within the same flask.…”

Section: Resultsmentioning

confidence: 67%

Section: Resultsmentioning

confidence: 95%

mentioning

confidence: 74%

Section: Autoradiographymentioning

confidence: 99%

“…We proposed an interpretation of the variable presence of hypoxia in some xenografted glioma lines (Parliament et al 1997).…”

mentioning

confidence: 99%

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Variable presence of hypoxia in M006 human glioma spheroids and in spheroids and xenografts of clonally derived sublines

Franko¹,

Parliament²,

Allalunis-Turner³

et al. 1998

Br J Cancer

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Implantable polymers for tirapazamine treatments of experimental intracranial malignant glioma

Yuan¹,

Tabassi

Williams

1999

Radiat. Oncol. Investig.

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Malignant gliomas remain refractory to intensive radiotherapy and cellular hypoxia enhances clinical radioresistance. Under hypoxic conditions, the benzotriazine di‐N‐oxide (3‐amino‐1,2,4‐benzotriazine 1,4‐dioxide) (tirapazamine) is reduced to yield a free‐radical intermediate that results in DNA damage and cellular death. For extracranial xenografts, tirapazamine treatments have shown promise. We therefore incorporated tirapazamine into the synthetic, biodegradable polymer, measured the release, and tested the efficacy both alone and in combination with external beam radiotherapy in the treatment of experimental intracranial human malignant glioma xenografts. The [(poly(bis(p‐carboxyphenoxy)‐propane) (PCPP):sebacic acid (SA) (PCPP:SA ratio 20:80)] polymer was synthesized. The PCPP:SA polymer and solid tirapazamine were combined to yield proportions of 20% or 30% (wt/wt). Polymer discs (3 × 2 mm) (10 mg) were incubated (PBS, 37°C), and the proportion of the drug released vs. time was recorded. Male nu/nu nude mice were anesthetized and received intracranial injections of 2 × 105 U251 human malignant glioma cells. For single intraperitoneal (i.p.) drug and/or external radiation treatments, groups of mice had i.p. 0.3 mmol/kg tirapazamine, 5 Gy cranial irradiation, or combined treatments on day 8 after inoculation. For fractionated drug and radiation treatments, mice had i.p. 0.15 mmol/kg tirapazamine, 5 Gy radiation, or combined treatments on days 8 and 9 after inoculation. For intracranial (i.c.) polymer treatments, mice had craniectomies and intracranial placement of polymer discs at the site of cellular inoculation. The maximally tolerated percentage loading of tirapazamine in the polymer disc was determined. On day 7 after inoculation, groups of mice had i.c. empty or 3% tirapazamine alone or combined with radiation (5 Gy × 2 doses) or combined with i.p. drug (0.15 mmol/kg × 2 doses on days 8 and 9). Survival was recorded. Polymers showed controlled, protracted in vitro release for over 100 days. The 5 Gy × 1 treatment resulted in improved survival; 28.5 ± 3.7 days (P = 0.01 vs. controls), while the single i.p. 0.3 mmol/kg tirapazamine treatment, 17.5 ± 1.9 days (P = NS) and combined treatments; 21.5 ± 5.0 days (P = NS) were not different. The fractionated treatments: 5 Gy × 2, i.p. 0.15 mmol/kg tirapazamine × 2 and the combined treatments resulted in improved survival: 44.5 ± 3.9 (P < 0.001), 24.5 ± 2.3 (P = 0.05) and 50.0 ± 6.0 (P < 0.001), respectively. Survival after intracranial empty polymer was 16.5 ± 3.0 days and increased to 31.0 ± 3.0 (P = 0.003) days when combined with the 5 Gy × 2 treatment. The survival after the polymer bearing 3% tirapazamine alone vs. combined with radiation was not different. The combined 3% tirapazamine polymer, i.p. tirapazamine, and radiation treatments resulted in both early deaths and the highest long‐term survivorship. The basis for potential toxicity is discussed. We conclude that implantable biodegradable polymers provide controlled intracranial release for tr...

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Introducing fluorine-18 fluoromisonidazole positron emission tomography for the localisation and quantification of pig liver hypoxia

Piert

Machulla

Becker

et al. 1999

European Journal of Nuclear Medicine and Molecular Imaging

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Fluorine-18 labelled fluoromisonidazole ([18F]FMISO) has been shown to accumulate in hypoxic tissue in inverse proportion to tissue oxygenation. In order to evaluate the potential of [18F]FMISO as a possible positron emission tomography (PET) tracer for imaging of liver tissue hypoxia, we measured the [18F]FMISO uptake in 13 domestic pigs using dynamic PET scanning. Hypoxia was induced by segmental arterial hepatic occlusion. During the experimental procedure the fractional concentration of inspired oxygen (FiO2) was set to 0.67 in group A (n=6) and to 0.21 in group B (n=7) animals. Before and after arterial occlusion, the partial pressure of O2 in tissue (TPO2) and the arterial blood flow were determined in normal flow and flow-impaired liver segments. Standardised uptake values [SUV=kBq tissue (in g) / body weight (in kg) x injected dose (in kBq)] for [18F]FMISO were calculated from PET images obtained 3 hours after injection of about 10 MBq/kg body weight [18F]FMISO. Immediately before PET scanning, the mean arterial blood flow was significantly decreased in arterially occluded segments [group A: 0. 41 (0.32-0.52); group B: 0.24 (0.16-0.33) ml min-1 g-1] compared with normal flow segments [group A: 1.05 (0.76-1.46); group B: 1.14 (0.83-1.57) ml min-1 g-1; geometric mean (95% confidence limits); P<0.001 for both groups]. After PET scanning, the TPO2 of occluded segments (group A: 5.1 (4.1-6.4); group B: 3.5 (2.6-4.9) mmHg] was significantly decreased compared with normal flow segments [group A: 26.4 (21.2-33.0); group B: 18.2 (13.3-25.1) mmHg; P<0.001 for both groups]. During the 3-h PET scan, the mean [18F]FMISO SUV determined in occluded segments increased significantly to 3.84 (3.12-4.72) in group A and 5.7 (4.71-6.9) in group B, while the SUV remained unchanged in corresponding normal liver tissue [group A: 1.4 (1.14-1. 71); group B: 1.31 (1.09-1.57); P<0.001 for both groups]. Regardless of ventilation conditions, a significant inverse exponential relationship was found between the TPO2 and the [18F]FMISO SUV (r2=0. 88, P<0.001). Our results suggest that because tracer delivery to hypoxic tissues was maintained by the portal circulation, the [18F]FMISO accumulation in the liver was found to be directly related to the severity of tissue hypoxia. Thus, [18F]FMISO PET allows in vivo quantification of pig liver hypoxia using simple SUV analysis as long as tracer delivery is not critically reduced.

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Anomalous patterns of nitroimidazole binding adjacent to necrosis in human glioma xenografts: possible role of decreased oxygen consumption

Cited by 37 publications

References 30 publications

Variable presence of hypoxia in M006 human glioma spheroids and in spheroids and xenografts of clonally derived sublines

Variable presence of hypoxia in M006 human glioma spheroids and in spheroids and xenografts of clonally derived sublines

Implantable polymers for tirapazamine treatments of experimental intracranial malignant glioma

Introducing fluorine-18 fluoromisonidazole positron emission tomography for the localisation and quantification of pig liver hypoxia

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