Pharmacologic intervention with angiotensin II and kininase inhibitor enhanced efficacy of radioimmunotherapy in human colon cancer xenografts

Autor: S, Kinuya, K, Yokoyama, A, Kawashima, T, Hiramatsu, S, Konishi, N, Shuke, N, Watanabe, T, Takayama, T, Michigishi, N, Tonami
Rok vydání: 2000
Předmět:
Zdroj: Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 41(7)
ISSN: 0161-5505
Popis: Induced hypertension and kininase inhibition can enhance tumor targeting of radiolabeled monoclonal antibody (MAb) by altering tumor circulation. This study investigated the effect of this manipulation on the antitumor efficacy of radioimmunotherapy (RIT).Mice bearing human colon cancer xenografts were administered 2.0 microg/kg/min of angiotensin II (AT-II) for 1 h and 30 microg of a kininase inhibitor, enalapril maleate, before the administration of 3.7 MBq (131)I-A7, an IgG1 against 45-kDa glycoprotein on colorectal cancer, and tumor growth was observed thereafter. The mechanism of the manipulation effect was investigated by estimation of the tissue absorbed dose and radioluminography of tumors.The pharmacologic manipulation with AT-II and enalapril improved the tumor quadrupling time (Tq) of 3.7 MBq RIT from 24.3 +/- 2.75 d to 33.1 +/- 2.83 d (P0.05). Addition of this manipulation made 3.7 MBq RIT as effective as 9.25 MBq RIT alone (Tq, 37.2 +/- 2.97 d). Dose estimation showed that the manipulation increased the tumor absorbed dose 1.55-fold without affecting the doses to normal tissues. Uniform intratumoral distribution in the manipulated tumors was shown by radioluminography.Larger and more uniform tumor radiation produced by this pharmacologic manipulation can benefit RIT with (131)I-MAb.
Databáze: OpenAIRE