Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C1658953 (tumor vasculature)
 2,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have evaluated gene transfer efficiency to tumor nodules in diethylnitrosoamine (DENA)-induced hepatocellular carcinoma (HCC) in rats using adenoviral vectors administered by three different routes: intraportal, intra-arterial and intratumoral injection. Our results showed that intraportal infusion could not transduce tumor nodules greater than 1 mm in diameter while the intra-arterial route allowed transduction of nodules up to 2-5 mm in diameter. Tumors greater than this size were resistant to transduction by intravascular route, but could be transduced by direct intratumoral injection, indicating that the obstacle preventing gene transfer to tumor cells was mainly at the level of tumor vasculature and not at the level of neoplastic cells. We have studied the extracellular matrix in tumoral lesions to assess whether nodules with different size and histological pattern have different profiles in relation to transduction efficacy. Immunohistochemical detection showed a high expression of fibronectin (FN), laminin (LN) and alpha-smooth muscle actin (alpha-SMA) in those large HCC, which were resistant to adenoviral infection. Intra-arterial infusion of vasoactive compounds (histamine, angiotensin II or nitric oxide donor nitroglycerin) before vector administration enhanced gene transfer to tumor nodules that were poorly transduced without pre-treatment. Nitroglycerin was active to enhance transduction of large tumors with trabecular or pseudoglandular histological pattern, which were impermeable to adenoviral vectors even after histamine or angiotensin treatments. Our data indicate the presence of a physical barrier between blood and neoplastic cells, which prevents transduction of the tumor by vectors given by the intravascular route. The thickness and impermeability of the barrier increases as the tumor nodule grows. Vasoactive compounds may be of value in gene therapy of liver cancer by increasing transduction efficiency by intravascularly administered vectors.
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PMID:A blood-tumor barrier limits gene transfer to experimental liver cancer: the effect of vasoactive compounds. 1111 Apr 14

Angiotensin II receptor type 1 blockers (ARBs), widely used antihypertensive drugs, have also been investigated for their anticancer effects. The effect of ARBs on prostate cancer in experimental models compared with meta-analysis data from clinical trials is conflicting. Whereas this discrepancy might be due to the use of supratherapeutic doses of ARBs in cellular and animal models as compared with the clinical doses used in human trials, further investigation of the effects of clinical doses of ARBs on prostate cancer in experimental models is warranted. In the current study, we sought to determine the effects of candesartan on prostate cancer cellular function in vitro and tumor growth in vivo, and characterize the underlying mechanisms. Our analysis indicated that clinically relevant doses of candesartan significantly inhibited growth of PC3 cell tumor xenografts in mice. Interestingly, the same concentrations of candesartan actually promoted prostate cancer cellular function in vitro, through a modest but significant inhibition in apoptosis. Inhibition of tumor growth by candesartan was associated with a decrease in vascular endothelial growth factor (VEGF) expression in tumors and inhibition of tumor angiogenesis, but normalization of tumor vasculature. Although candesartan did not impair PC3 cell viability, it inhibited endothelial-barrier disruption by tumor-derived factors. Furthermore, candesartan significantly inhibited expression of VEGF in PC3 and DU145 cell lines independent of angiotensin II type 2 receptor, but potentially via angiotensin II type 1 receptor inhibition. Our findings clearly demonstrate the therapeutic potential of candesartan for prostate cancer and establish a link between ARBs, VEGF expression, and prostate tumor angiogenesis.
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PMID:Clinically relevant doses of candesartan inhibit growth of prostate tumor xenografts in vivo through modulation of tumor angiogenesis. 2499 Sep 40