PubMed Health⌕ Search

PubMed · 15280064

Decrease in tumor apparent permeability-surface area product to a MRI macromolecular contrast medium following angiogenesis inhibition with correlations to cytotoxic drug accumulation.

Abstract

BACKGROUND: New strategies for cancer therapy include the combination of angiogenesis inhibitors with cytotoxins. However, angiogenesis inhibitors may alter tumor microvessel structure and transendothelial permeability thereby reducing tumoral delivery of cytotoxic agents. The aim of this study was to estimate quantitatively the apparent permeability-surface area product (K(PS)) in tumors to a macromolecular contrast medium (MMCM), to follow changes in K(PS) induced by antibodies to vascular endothelial growth factor (anti-VEGF), and to correlate the findings with tumor accumulation of cisplatin, a highly protein-bound cytotoxin, and 5-fluorouracil (5-FU), a small unbound cytotoxin. METHODS: Dynamic MRI enhanced with a MMCM (albumin-(Gd-DTPA)(30)) was analyzed using a two-compartment tumor tissue model (plasma and interstitial water) to quantitatively estimate K(PS). These estimates of K(PS) were correlated with cytotoxic drug accumulations in the tumors. RESULTS: Anti-VEGF treatment reduced K(PS) to MMCM in tumor tissue from 0.013 mL h(-1) cm(-3) (n = 9) at baseline to 0.003 mL h(-1) cm(-3) (n = 9) 24 h later (p <.05). The K(PS) values correlated significantly (r(2) =.78; p <.0001) with the tumor cisplatin accumulation. No correlation (r(2) =.001; p =.89) was found between K(PS) and tumor accumulation of the substantially smaller 5-FU molecule. CONCLUSIONS: MMCM-enhanced MRI can be used to detect and estimate changes in K(PS) to this contrast agent following a single dose of anti-VEGF antibody. The decline in K(PS) induced by this inhibitor of angiogenesis is associated with reduced tumor concentration of a protein-bound cytotoxin, similar in molecular weight to the contrast agent. MRI assays of microvascular status as performed here may be useful to clinically monitor responses to anti-angiogenesis drugs and to optimize the choice and timing of cytotoxic drug administration.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Heike E Daldrup-Link, Yoshitaka Okuhata, Allan Wolfe, Sudesk Srivastav, Sven Øie, Napoleone Ferrara, Robert L Cohen, David M Shames, Robert C Brasch. Decrease in tumor apparent permeability-surface area product to a MRI macromolecular contrast medium following angiogenesis inhibition with correlations to cytotoxic drug accumulation.. https://doi.org/10.1080/10739680490457665

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Anti-angiogenic therapy subsequent to adeno-associated-virus-mediated immunotherapy eradicates lymphomas that disseminate to the liver.

Liver cancer has a very poor prognosis and lacks effective therapy. We have previously demonstrated that intraportal injection of adeno-associated-viral (AAV) particles that express angiostatin lead to long-term expression of angiostatin capable of suppressing the outgrowth of EL-4 tumors in the liver. Here we combine AAV-mediated angiostatin therapy with immunotherapy by employing an AAV vector encoding the T-cell costimulator B7.1. Incubation of EL-4 cells with AAV-B7.1 viruses resulted in the rapid expression of B7.1 on the surface of 80% of EL-4 cells. Mice that were vaccinated with B7.1-engineered tumor cells rejected the tumor cells and resisted a secondary challenge with unmodified parental cells. Splenocytes from the vaccinated mice were highly cytotoxic towards parental EL-4 cells in vitro. However, the vaccinated mice failed to resist the challenge of a heavy burden of EL-4 cells. Intraportal injection of AAV particles that express angiostatin into mice that had been vaccinated 1 month earlier with B7.1-engineered tumor cells protected mice against the challenge of a heavy burden of EL-4 cells and eradicated tumors that had disseminated to the liver. The combinational therapy increased the survival rate of mice with advanced liver cancer. These encouraging results warrant investigation of the employment of anti-angiogenic therapy subsequent to cancer immunotherapy for targeting unresectable disseminated liver metastases.

Angiogenesis Inhibitors↗

Increased endothelial uptake of paclitaxel as a potential mechanism for its antiangiogenic effects: potentiation by Cox-2 inhibition.

Paclitaxel has antiangiogenic properties, but the mechanisms for the enhanced sensitivity of endothelial cells (ECs) to this drug are not established. The aims of our study were to compare the distribution of paclitaxel into ECs with other cell types, to assess the effects of low doses of paclitaxel on Cox-2 expression and to determine the combined effects of paclitaxel and Cox-2 inhibitors on angiogenesis in vitro and in patients with cancer. Upon exposure to low (5 nM) concentrations of [3H]-paclitaxel, uptake of radioactivity was more than 5 times higher in ECs than other cell types. Exposing human umbilical vein ECs to low nanomolar (1-50 nM) concentrations of paclitaxel enhanced Cox-2 expression more than 2-fold, as measured by ELISA. Combined treatment with paclitaxel and the Cox-2 inhibitor NS-398 resulted in increased antiendothelial effects as compared to each agent alone. To assess the biologic effects of the combined treatment in vivo, 4 cancer patients were treated with a prolonged intravenous infusion of paclitaxel (10 mg/m2/day) and the Cox-2 inhibitor celecoxib (400 mg p.o. BID), and plasma angiogenic activity and drug levels were measured. The treatment was well tolerated, providing steady-state concentrations of paclitaxel in plasma near 10 nM and potent plasma antiendothelial effects were observed. These findings suggest that antiangiogenic effects of paclitaxel may be due its preferential accumulation in ECs. Low dose paclitaxel in combination with a Cox-2 inhibitor is an attractive antiangiogenic and antitumor strategy that deserves further evaluation in clinical trials.

Angiogenesis Inhibitors↗

Antiangiogenic cancer gene therapy by adeno-associated virus 2-mediated stable expression of the soluble FMS-like tyrosine kinase-1 receptor.

Antiangiogenic gene transfer has the potential to be more efficacious than protein-based therapies or pharmacotherapies for the control of solid tumor growth, invasion and metastasis. For a sustained antiangiogenic effect, a vector capable of long-term expression without vector-associated immunity or toxicity is advantageous. The present study evaluated the potential of a recombinant adeno-associated virus-2 (rAAV) encoding the human soluble FMS-like tyrosine kinase receptor 1 (sFlt-1), which functions by both sequestering vascular endothelial growth factor (VEGF) and forming inactive heterodimers with other membrane-spanning VEGF receptors, in vitro and in vivo. Results indicated significant growth inhibitory activity of the transgenic factor in a human umbilical vein endothelial cell proliferation assay in vitro and protection against the growth of an angiogenesis-dependent human ovarian cancer cell line, SKOV3.ip1, xenograft in vivo with increased disease-free survival. Stable expression of the secretory factor and transgene persistence were confirmed by immunohistochemistry and in situ hybridization analyses, respectively. Increased therapeutic effects on both the growth index of the implanted tumor cells and tumor-free survival also correlated with an increasing dose of the vector used. These studies indicate that rAAV-mediated sFlt-1 gene therapy may be a feasible approach for inhibiting tumor angiogenesis, particularly as an adjuvant/therapy.

Angiogenesis Inhibitors↗