[Study about the growth of two tumors of the solid Yoshida sarcoma of the rat in the same animals as well as about the reactions of tumors of different sizes to treatment with 2-, 3-, 5-trisethyleneiminobenzochinone (1,4) (author's transl)]

Free radical formation by antitumor quinones

Quinones are among the most frequently used drugs to treat human cancer. All of the antitumor quinones can undergo reversible enzymatic reduction and oxidation, and form semiquinone and oxygen radicals. For several antitumor quinones enzymatic reduction also leads to formation of alkylating species but whether this involves reduction to the semiquinone or the hydroquinone is not always clear. The antitumor activity of quinones is frequently linked to DNA damage caused by alkylating species or oxygen radicals. Some other effects of the antitumor quinones, such as cardiotoxicity and skin toxicity, may also be related to oxygen radical formation. The evidence for a relationship between radical formation and the biological activity of the antitumor quinones is evaluated.

The pharmacology of diaziquone given in intravenous or intracarotid infusion to normal and intracranial tumor-bearing puppies

Diaziquone (also called "aziridinyl benzoquinone," or AZQ), an antitumor drug designed to penetrate the blood-brain barrier, has demonstrated activity against central nervous system (CNS) neoplasms. Four-hour infusions of carbon-14 (14C)-labeled AZQ (0.8 mg/kg) were given via the left common carotid artery or left brachial vein to two groups of puppies. A third group, harboring a transplantable canine glioma, received 14C-AZQ by intravenous infusion. Levels of chloroform (CHCl3)-extractable 14C (AZQ only) and total 14C (AZQ and metabolites) were determined in serial samples of plasma and cerebrospinal fluid (CSF). At the end of the infusion time, total and CHCl3-extractable 14C levels were determined in brain and tumor. Intra-arterial infusion of AZQ caused no histological abnormalities in the retina or brain. For the intravenous infusion group, the concentrations of CHCl3-extractable 14C (in nmol/ml or nmol/gm) were 0.68, 0.35, and 0.84 for plasma, brain, and CSF, respectively. For the intra-arterial infusion group, the concentrations were 0.25, 0.13, and 0.32 for plasma, brain, and CSF, respectively. Comparison of right and left hemispheres following intra-arterial infusion showed a slightly higher concentration of 14C in the ipsilateral (left) hemisphere, with concentrations (nmol/gm) of CHCl3-extractable 14C/total of 14C of 0.15/0.87 on the left and 0.12/0.65 on the right. Concentrations (nmol/gm) of CHCl3-extractable 14C/total 14C in brain and tumor were 0.60/1.24 and 0.58/1.65, respectively. In tumor-bearing animals, tumor and surrounding brain contained similar concentrations of AZQ, but there were higher concentrations of metabolites in tumor. This may reflect different metabolism of AZQ within brain and tumor or different permeability to metabolites. This study revealed that AZQ enters the CNS and brain-tumor tissue in substantial concentrations and that there is no significant advantage to intracarotid infusion of AZQ.

Potential CNS antitumor agents VI: aziridinylbenzoquinones III

Thirty-one aziridinylbenzoquinones were compared against five murine tumor models in vivo. Two intracerebral (ependymoblastoma and L-1210 leukemia) and three intraperitoneal (P-388 and L-1210 leukemia and B16 melanoma) systems were utilized. Excellent activity was observed for many compounds. Multiple long-term survivors were produced in the ependymoblastoma, P-388, and intraperitoneal L-1210 systems. Diethyl 2,5-bis(1-aziridinyl)-3,6-dioxo-1,4-cyclohexadiene-1,4-dicarbamate demonstrated superior activity in all five test systems. This compound also was reproducibly active against two colon tumors, a mammary tumor, and the intracerebrally implanted P-388 leukemia model.