Temporal heterogeneity in microregional erythrocyte flux in experimental solid tumours

Dj, Chaplin; Hill, SA

doi:10.1038/bjc.1995.235

Cited by 93 publications

(58 citation statements)

References 8 publications

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“…The counting of vessels does not seem to reflect their perfusion status. Many tumour vessels are only perfused temporarily (Chaplin and Hill, 1995), or sometimes not at all (Vajkoczy et al, 2000). In addition to vascular length, tissue perfusion is determined by mean vessel diameter, flow resistance, and erythrocyte velocity (Intaglietta and Zweifach, 1974;Leunig et al, 1992;Baish et al, 1996;Vajkoczy et al, 1998).…”

Section: Anti-vegf Mab Does Not Impair Intratumoral Cpt-11 Deliverymentioning

confidence: 99%

Effect of antivascular endothelial growth factor treatment on the intratumoral uptake of CPT-11

Wildiers¹,

Guetens²,

Boeck³

et al. 2003

Br J Cancer

298

150

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Promising preclinical activity with agents blocking the function of vascular endothelial growth factor (VEGF) has been observed in various cancer types, especially with combination therapy. However, these drugs decrease microvessel density, and it is not known whether this reduced vessel density (VD) results in decreased delivery of concomitantly administered classical anticancer drugs. We designed an in vivo study to investigate the relation between VEGF-blocking therapy, tumoral blood vessels, and intratumoral uptake of anticancer drugs. Nude NMRI mice bearing colon adenocarcinoma (HT29) were treated with the anti-VEGFmAb A4.6.1 or placebo. After 1 week, CPT-11 was administered 1 h prior to killing the animals. In A4.6.1 treated tumours, there was a significant decrease in VD, more pronounced with potentially functional large vessels than endothelial cords. Interestingly, a trend to increased intratumoral CPT-11 concentration was observed (P ¼ 0.09). In parallel, we measured an increase in tumour perfusion, as estimated by high-performance liquid chromatography determination of intratumoural Hoechst 33342 concentration. In the growth delay study, CPT-11 was at least equally effective with or without pretreatment with A4.6.1. These data suggest that tumour vascular function and tumour uptake of anticancer drugs improve with VEGF-blocking therapy, and indicate the relevance for further investigations.

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Section: Anti-vegf Mab Does Not Impair Intratumoral Cpt-11 Deliverymentioning

confidence: 99%

Effect of antivascular endothelial growth factor treatment on the intratumoral uptake of CPT-11

Wildiers¹,

Guetens²,

Boeck³

et al. 2003

Br J Cancer

298

150

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“…A system of changing oxygenation aimed at mimicking those transient hypoxic conditions found in solid tumours (Brizel et al, 1995;Chaplin and Hill, 1995) was utilized to further test the effect of tumour conditions on gene transfer. Reoxygenation of T24 cells for different lengths of time (0-24 h) after anoxic transfection (2 h + 5 h anoxia) showed the same transfection efficiency as aerobic controls ( Figure 4A).…”

Section: Hypoxic Transfection Efficiency: Effect Of Transient Anoxiamentioning

confidence: 99%

Gene delivery to hypoxic cells in vitro

et al. 2000

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Summary Hypoxia in solid tumours has been correlated with poor prognosis and resistance to radiation and chemotherapy. Hypoxia is also a strong stimulus for gene expression. We previously proposed a gene therapy approach which exploits the presence of severe hypoxia in tumours for the induction of therapeutic genes. Hypoxic cells are known to have a reduced metabolic rate, transcription and translation. These facts may prevent gene transfer and therefore warranted further investigation. In this paper the feasibility of gene delivery in vitro under tumour conditions was demonstrated. DNA was delivered in vitro using a peptide-mediated non-viral system. Across a range of oxygen tensions and mammalian cell lines (including human tumour and endothelial cells) it was shown that hypoxic cells could be transfected. Transfection efficiencies varied depending on the level of hypoxia, cell characteristics and gene promoters used. An in vitro model of hypoxia/reoxygenation, designed to mimic the variable nature of tumour hypoxia, showed that hypoxic preconditioning and reoxygenation alone did not reduce transfection efficiency significantly; only chronic anoxia reduced transfection. The fact that neither intermediate hypoxia nor intermittent anoxia significantly reduced transfection is promising for future hypoxia-targeted gene therapy strategies. 662-667 © 2000 Cancer Research Campaign doi: 10.1054/ bjoc.2000.1318, available online at http://www.idealibrary.com on List of abbreviations: HIF-1, hypoxia inducible factor 1; CMV, cytomegalovirus; SV40, simian virus 40; AnO 2 , anoxia; GFP, green fluorescent protein; FACS, fluorescent activated cell sorting Transfection efficiencies of two commonly used marker genes and viral promoters were recorded in a range of cell lines under different oxygenation conditions. A simple in vitro model of hypoxia/reoxygenation was used to mimic the variable nature of tumour hypoxia. MATERIALS AND METHODS Cell lines and growth mediaThe human bladder carcinoma cell line T24 (European Collection of Cell Cultures; Bubenik et al, 1973;Dirks et al, 1999), the immortalized human microvascular endothelial cell line HMEC-1 (Ades et al, 1992), human squamous carcinoma cell line of the head and neck FaDu (Rangan, 1972; American Type Culture Collection), the mouse hepatoma cell line Hepa-1 wild type (clone Hepa-1c1c7) and its derivative Hepa c4 (HIF-1β mutant; Hankinson, 1979) were utilised. Only cells tested negative for mycoplasma were used in the experiments, since it had been shown that mycoplasma interfered with transfection, especially under hypoxia (results not shown). All cells were maintained in Dulbecco's MEM (DMEM, Life Technologies, UK) with 10% fetal calf serum and L-glutamine in a 5% CO 2 humidified incubator at 37°C.Cell proliferation was monitored by cell counting using a haemocytometer and trypan blue (0.2% final concentration, Sigma) to distinguish live and dead cells. Hypoxic conditionsCells were plated 16-24 h prior to the experiment in oxygen impermeable dishes (Permanox, Nunc, UK...

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“…14 Using laser-Doppler technology, temporal variations in perfusion have been seen in both experimental and human tumors. [15][16][17] Kimura et al demonstrated that temporal instability in tumor red blood cell flux could lead to transient hypoxia. 18 Dewhirst et al linked temporal changes in microvessel red blood cell flux with changes in the oxygen content in the same vessel.…”

Section: Introductionmentioning

confidence: 99%

Assessment of tumor oxygenation by electron paramagnetic resonance: principles and applications

2004

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This review paper attempts to provide an overview of the principles and techniques that are often termed electron paramagnetic resonance (EPR) oximetry. The paper discusses the potential of such methods and illustrates they have been successfully applied to measure oxygen tension, an essential parameter of the tumor microenvironment. To help the reader understand the motivation for carrying out these measurements, the importance of tumor hypoxia is first discussed: the basic issues of why a tumor is hypoxic, why these hypoxic microenvironments promote processes driving malignant progression and why hypoxia dramatically influences the response of tumors to cytotoxic treatments will be explained. The different methods that have been used to estimate the oxygenation in tumors will be reviewed. To introduce the basics of EPR oximetry, the specificity of in vivo EPR will be discussed by comparing this technique with NMR and MRI. The different types of paramagnetic oxygen sensors will be presented, as well as the methods for recording the information (EPR spectroscopy, EPR imaging, dynamic nuclear polarization). Several applications of EPR for characterizing tumor oxygenation will be illustrated, with a special emphasis on pharmacological interventions that modulate the tumor microenvironment. Finally, the challenges for transposing the method into the clinic will also be discussed.

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Temporal heterogeneity in microregional erythrocyte flux in experimental solid tumours

Cited by 93 publications

References 8 publications

Effect of antivascular endothelial growth factor treatment on the intratumoral uptake of CPT-11

Effect of antivascular endothelial growth factor treatment on the intratumoral uptake of CPT-11

Gene delivery to hypoxic cells in vitro

Assessment of tumor oxygenation by electron paramagnetic resonance: principles and applications

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