Biomedical subjects

B B Hasinoff

Publications and source records attributed to B B Hasinoff.

At least 37 records · Page 2Linked to original sources

PubMed1997

Comparison of the structural changes induced by doxorubicin and mitoxantrone in the heart, kidney and intestine and characterization of the Fe(III)-mitoxantrone complex.

Histologic, nick end labeling for apoptosis and electron microscopic studies were made of the heart, kidney and small intestine in spontaneously hypertensive rats (SHR) treated for 12 weeks with doxorubicin (1 mg/kg/week), mitoxantrone (0.5 or 0.25 mg/kg/week) or saline (controls). Semiquantitative scoring showed that the severity of the cardiac lesions produced by doxorubicin was comparable to that resulting from 0.5 mg/kg mitoxantrone, but greater than that induced by 0.25 mg/kg mitoxantrone (to which it is therapeutically equivalent). The nephropathy and the intestinal toxicity produced by doxorubicin were also more severe than those resulting from either dose of mitoxantrone. Apoptosis of cardiac myocytes was not induced by either drug, but involved cardiac dendritic cells in SHR given doxorubicin. Apoptosis in renal tubular epithelium was comparable in SHR given doxorubicin and the higher dose of mitoxantrone. Doxorubicin induced more frequent apoptosis in intestinal epithelium than did the higher dose of mitoxantrone. We also show that mitoxantrone and iron(III) form a strong 2:1 complex, in which the drug may be acting as a tridentate ligand. This complex, like the iron(III)-doxorubicin complex, may be capable of redox cycling and producing reactive oxygen intermediates (ROI) that damage tissue. Decreased formation of ROI by mitoxantrone may account for its reduced cardiotoxicity compared to that of doxorubicin.

Animals↗

PubMed1997

Comparison of the protective effects against chronic doxorubicin cardiotoxicity and the rates of iron (III) displacement reactions of ICRF-187 and other bisdiketopiperazines.

Histologic and biochemical studies were carried out to compare the protective activity of various bisdiketopiperazines against the cardiac and renal toxicity induced by doxorubicin in spontaneously hypertensive rats (SHR), a well-established animal model of this disorder, with: (1) the rates of hydrolysis of these agents to form the iron-chelating derivatives (which are considered to cause a decrease in the formation of reactive oxygen intermediates) and (2) the ability of these derivatives to bind iron. SHR were given 12 weekly injections of doxorubicin, 1 mg/kg i.v. either alone or 30 min after the administration of ICRF-154, ICRF-187, ICRF-192, ICRF-197, ICRF-198, ICRF-239 and ADR-559. Semiquantitative grading of the severity of the resulting cardiac and renal lesions showed that ICRF-187, ICRF-154 and ADR-559 were the most protective, whereas ICRF-197 and ICRF-239 provided intermediate degrees of protection, and ICRF-192 and ICRF-198 were not protective. Quantitative measurements in vitro revealed only relatively small differences in the rates of opening of the two diketopiperazine rings of the various agents to form the corresponding iron-chelating diacid diamide derivatives, and in the ability of these various derivatives to remove iron from the iron-doxorubicin complex. Such differences showed no relationship with cardioprotective activity. Some bisdiketopiperazines (including ICRF-154 and ICRF-187) with cardioprotective activity also are inhibitors of DNA topoisomerase II; however, the significance of this relationship remains uncertain, since ADR-925, the open-ring derivative of ICRF-187, does not inhibit DNA topoisomerase II.

Animals↗

PubMed1997

Mitindomide is a catalytic inhibitor of DNA topoisomerase II that acts at the bisdioxopiperazine binding site.

The antitumor drug mitindomide (NSC 284356) was shown to inhibit the decatenation activity of human and Chinese hamster ovary (CHO) topoisomerase II [DNA topoisomerase (ATP-hydrolyzing), EC 5.99.1.1]. Mitindomide did not induce the formation of topoisomerase II-DNA covalent cleavable complexes in CHO cells. These results taken together indicate that mitindomide is a catalytic/noncleavable complex-forming-type inhibitor of topoisomerase II. The growth inhibitory effects of mitindomide and dexrazoxane toward a sensitive parent CHO cell line and the dexrazoxane-resistant DZR cell line, which is highly (500-fold) resistant to the bisdioxopiperazine dexrazoxane, were measured. The DZR cell line was shown to be 30-fold cross-resistant to mitindomide. Mitindomide, like dexrazoxane, was shown to inhibit cleavable complex formation by the topoisomerase II poison etoposide. The attenuated inhibition of etoposide-induced cleavable complexes in DZR compared with CHO cells was, likewise, very similar for dexrazoxane and mitindomide. Together these results suggest that mitindomide acts at the same site on topoisomerase II as does dexrazoxane and other bisdioxopiperazines. Various molecular parameters obtained by molecular modeling were compared for mitindomide and dexrazoxane. Mitindomide, which is conformationally very rigid, has highly coplanar imide rings, as does dexrazoxane in the solid state. Other molecular parameters, such as the imide nitrogen-to-imide nitrogen bond distances, and polar and nonpolar surface areas were also very similar. Thus, it is concluded that mitindomide exerts its antitumor effects through its inhibition of topoisomerase II by binding to the bisdioxopiperazine binding site.

Animals↗

PubMed1996

Collateral sensitivity to the bisdioxopiperazine dexrazoxane (ICRF-187) in etoposide (VP-16)-resistant human leukemia K562 cells.

Etoposide (VP-16)-resistant K562 cells (K/VP.5) were 26-fold resistant to VP-16, due in part to a reduction in DNA topoisomerase II (topoisomerase II) protein levels. Compared with parental K562 cells, VP-16-resistant K/VP.5 cells were found to be 3.4-fold more sensitive to the effects of dexrazoxane (ICRF-187), a topoisomerase II inhibitor that does not stabilize topoisomerase II-DNA covalent complexes. In contrast, K/VP.5 cells were 4.0-fold cross-resistant to merbarone and showed no cross-resistance to fostriecin, two other topoisomerase II inhibitors that do not stabilize topoisomerase II-DNA covalent complexes. Preincubation with ICRF-187 resulted in greater inhibition of subsequent VP-16-induced topoisomerase II-DNA covalent complexes in K/VP.5 cells than in K562 cells. Conversely, preincubation with merbarone resulted in less inhibition of VP-16-induced topoisomerase II-DNA covalent complexes in K/VP.5 cells than in parental K562 cells. Preincubation with forstriecin had little effect on VP-16-induced topoisomerase II-DNA covalent complex formation in either cell line. The onset rates for ICRF-187 inhibition of VP-16-induced topoisomerase II-DNA complex formation were similar in sensitive and resistant cells. In addition, ICRF-187 had a comparable concentration-dependent inhibitory effect on the topoisomerase II catalytic activities of K562 and K/VP.5 cells. Together, our results indicate that collateral sensitivity to ICRF-187 in K/VP.5 cells is due to decreased topoisomerase II protein levels rather than to an alteration in topoisomerase II activity. Furthermore, results suggest that ICRF-187, merbarone, and fostriecin have different mechanisms of action that can be studied effectively in K/VP.5 and K562 cells.

Alkenes↗

PubMed1996

Inhibition of anthracycline semiquinone formation by ICRF-187 (dexrazoxane) in cells.

The formation of semiquinone free radicals of doxorubicin, epirubicin, daunorubicin, and idarubicin was measured by electron paramagnetic resonance (EPR) spectroscopy in hypoxic suspensions of chinese hamster ovary (CHO) cells. The amount of semiquinone produced was in the order idarubicin >> doxorubicin > daunorubicin > epirubicin. The idarubicin semiquinone signal was both the fastest to be formed and to decay. Idarubicin, which was the most lipophilic of the anthracyclines studied, also displayed the fastest fluorescence-measured cellular uptake of drug. Thus, it was concluded that semiquinone formation was dependent upon the rate of cellular uptake. Lysed cell suspensions were also shown to be capable of producing the doxorubicin semiquinone in the presence of added NADPH. The cardioprotective agent dexrazoxane (ICRF-187) was observed to decrease the amount of doxorubicin semiquinone observed in cell suspensions. Dexrazoxane also decreased the amount of doxorubicin semiquinone observed in the NADPH-lysed cell suspension mixture. Neither bipyridine nor deferoxamine decreased NADPH-dependent doxorubicin semiquinone formation. These results suggest that dexrazoxane does not decrease doxorubicin semiquinone formation through an iron complex formed from hydrolyzed dexrazoxane. Dexrazoxane may be inhibiting an NADPH-dependent enzyme.

Animals↗

PubMed1996

Ferrous sulfate does not reduce serum levels of famotidine or cimetidine after concurrent ingestion.

A series of randomized crossover studies were performed to determine whether there was a reduction in serum levels of cimetidine and famotidine when coingested with ferrous sulfate (300 mg). Coingestion of a ferrous sulfate tablet with cimetidine (300 mg) was associated with little reduction in serum cimetidine area under the curve (AUC) (mean versus mean, 20.8 versus 23.4 mumol.hr/L; mean percentage difference, -11%; 95% confidence interval [CI] of percentage difference, -26% to 4.2%) or peak concentration (Cmax) (mean versus mean, 5.1 versus 6.1 mumol/L; mean percentage difference, -16%; CI of percentage difference, -36% to 4%). Similarly, ferrous sulfate solution coingested with cimetidine caused little change in cimetidine AUC (mean versus mean, 19.9 versus 23.0 mumol.hr/L; mean percentage difference, -13%; CI of percentage difference, -34% to 7%) or Cmax (mean versus mean, 5.0 versus 5.0 mumol/L; mean percentage difference, 1%; CI of percentage difference, -18% to 20%). Concurrent ingestion of famotidine (40 mg) with a ferrous sulfate tablet did not result in significant reductions in serum famotidine AUC (mean versus mean, 1.78 versus 1.99 mumol.hr/L; mean percentage difference, -10%; CI of percentage difference, -34% to 13%) or Cmax (mean versus mean, 0.31 versus 0.32 mumol/L; mean percentage difference, -3%; CI of percentage difference, -27% to 22%). The formation of famotidine:iron(III) complexes was shown in methanol but was not observed in an aqueous buffer at pH 6.5. Ranitidine did not bind iron in an aqueous buffer and only weakly bound iron in methanol. Coingestion of ferrous sulfate with either cimetidine or famotidine does not cause a clinically relevant reduction in serum histamine H2-receptor blocker levels and, on the basis of in vitro binding experiments, iron is unlikely to interact with ranitidine.

Administration, Oral↗

PubMed1996

The effect of dexrazoxane (ICRF-187) on doxorubicin- and daunorubicin-mediated growth inhibition of Chinese hamster ovary cells.

Dexrazoxane (ICRF-187) is clinically used to reduce doxorubicin-induced cardiotoxicity. Because dexrazoxane, doxorubicin and daunorubicin all act on DNA topoisomerase II, a study was undertaken to see what effect dexrazoxane had on the growth inhibitory effects of doxorubicin and daunorubicin towards Chinese hamster ovary cells. Dexrazoxane exhibited significant antagonism of doxorubicin- and daunorubicin-mediated growth inhibition when the cells were preincubated with dexrazoxane before the anthracycline was added. Continuous exposure of cells to either anthracycline and low concentrations of dexrazoxane resulted in additive growth inhibitory effects at low anthracycline concentrations, and no effect at higher anthracycline concentrations.

Animals↗

PubMed1996

Brain samples from Alzheimer's patients have elevated levels of loosely bound iron.

The amount of loosely bound iron was measured in frontal cortex and cerebellum from autopsy brain samples from Alzheimer's patients and from non-demented, age matched controls. It was found that the amount of total iron and of ferric iron in Alzheimer's brain tissues was significantly higher compared to control samples in both regions studied. Neither the ferrous nor the ferrous to ferric ratio were found to be changed. Since it is the loosely bound iron that is responsible for free radical reactions in vivo, these results are consistent with an increased free radical burden in Alzheimer's disease that leads to the progressive neurodegeneration seen in this disorder.

Aged↗

PubMed1996

Semiquinone free radical formation by daunorubicin aglycone incorporated into the cellular membranes of intact Chinese hamster ovary cells.

The production of semiquinone free radicals has been measured by electron paramagnetic resonance spectroscopy (EPR) in Chinese hamster ovary cells in which 7-hydroxy daunorubicin aglycone had been incorporated. The highly lipophilic daunorubicin aglycone was incorporated into the cellular membrane by swirling a cell suspension over a thin layer of daunorubicin aglycone. Thus, the observed semiquinone free radical was likely formed directly in the lipophilic environment of the cellular membrane. The linewidth of the observed EPR signal suggested that a neutral protonated semiquinone species was formed. In the presence of the cell-impermeant paramagnetic line broadening agent chromium(III) oxalate, no detectable signal was observed. This result indicates that even though the semiquinone is embedded in the membrane, it is still partly accessible to the external chromium(III) oxalate. Analysis of chloroform extracts of the cells after EPR experiments indicated that daunorubicin aglycone was extensively metabolized. The results of a growth inhibition assay carried out on cells into which daunorubicin aglycone had been incorporated showed almost no effect on cell growth. This result indicates that in spite of significant daunorubicin aglycone-induced radical formation taking place directly in the cell membrane, little cell damage results.

Animals↗

PubMed1995

A QSAR study comparing the cytotoxicity and DNA topoisomerase II inhibitory effects of bisdioxopiperazine analogs of ICRF-187 (dexrazoxane).

A series of twelve structurally related bisdioxopiperazines that included ICRF-187 (dexrazoxane), ICRF-159 (razoxane), ICRF-193, and ICRF-154 were examined both for their ability to inhibit the growth of Chinese hamster ovary (CHO) cells and their ability to inhibit the catalytic activity of mammalian DNA topoisomerase II. The bisdioxopiperazines exhibited a wide range in both growth inhibitory effects (30,000-fold), and in their ability to inhibit the catalytic activity of topoisomerase II (150-fold). The cytotoxicity of the bisdioxopiperazines toward CHO cells was highly correlated (correlation coefficient r = 0.86, P = 0.0003) with their inhibition of the catalytic activity of DNA topoisomerase II. This result strongly suggests that DNA topoisomerase II is the functional target of the bisdioxopiperazines. The stereoisomers (+)-ICRF-187 and (-)-ICRF-186 were observed to be equally cytotoxic and equally inhibitory toward DNA topoisomerase II. This result indicates that the bisdioxopiperazine binding site on DNA topoisomerase II is large enough or flexible enough to accommodate either form of the drug. The strongly metal-ion binding fully rings-opened hydrolysis product of ICRF-187, ADR-925, demonstrated no measurable inhibitory activity toward DNA topoisomerase II or cytotoxicity toward CHO cells.

Animals↗

PubMed1995

Production of hydroxyl radical by iron(III)-anthraquinone complexes through self-reduction and through reductive activation by the xanthine oxidase/hypoxanthine system.

The iron(III) complexes of doxorubicin and epirubicin were observed to undergo a self-reduction (autoxidation) reaction in the absence of added reductants under aerobic conditions that resulted in the formation of ferrous anthracycline complexes. These self-reduction reactions resulted in significant hydrogen peroxide-mediated hydroxyl radical formation, as determined by electron paramagnetic resonance spin trapping. In contrast, the iron(III) complexes of daunorubicin, idarubicin, and mitoxantrone produced no significant amount of hydroxyl radical formation. Only the anthraquinones with an alpha-ketol side chain were observed to undergo both self-reduction and hydroxyl radical formation. Thus, the alpha-ketol side chain must be undergoing concomitant oxidation. The rate of self-reduction of the iron(III)-doxorubicin complex is consistent with a mechanism in which unbound doxorubicin binds to an iron(III)-doxorubicin complex of decreased coordination and after binding undergoes an intramolecular electron transfer. Molecular modeling was used to identify iron(III)-doxorubicin complexes that could result in electron transfer from the doxorubicin side chain hydroxyl group to the iron(III). All of the iron(III)-anthracycline complexes were able to produce hydroxyl radicals at significantly increased rates in the presence of the xanthine oxidase/hypoxanthine superoxide-generating system. In this system the iron(III)-epirubicin complex gave the greatest rate of hydroxyl radical production, with iron(III)-idarubicin giving the least.

Antibiotics, Antineoplastic↗

PubMed1995

Morphologic and morphometric evaluation of the effect of ICRF-187 on bleomycin-induced pulmonary toxicity.

Morphologic and morphometric studies were made of the protective effects of ICRF-187 against the pulmonary damage induced by bleomycin in male and female C57/BL6 mice. Sixty minutes prior to the subcutaneous administration of 15 mg/kg of bleomycin, animals received either saline or ICRF-187 (300 or 150 mg/kg) intraperitoneally, twice a week for 4 weeks. The lungs of animals treated with bleomycin alone showed inflammation, hyperplasia of type II epithelial cells, squamous cell metaplasia and fibrosis. The extent of fibrosis was quantified by means of a color videometric system and histologic sections of lung stained according to a modified Masson trichrome method. The severity of these alterations, particularly of fibrosis, was reduced in all groups of animals pretreated with ICRF-187. The fibrosis was reduced to a similar extent in female mice treated with the 300 mg/kg and the 150 mg/kg doses of ICRF-187, from 39.3% to 17.6% and 13.3%, respectively. ICRF-187 induced significantly different degrees of reduction in fibrosis in the 2 groups of male mice treated with the 150 mg/kg and the 300 mg/kg doses, from 30% to 19.7% and 12.2%, respectively. In vitro studies indicated that both ICRF-187 and its open-ring hydrolysis product (ADR-925) remove iron slowly from the bleomycin-iron complex. This observation provides a basis for the concept that ICRF-187 protects by chelating iron involved in the formation of the bleomycin-Fe3+ complex that generates reactive oxygen radicals capable of causing pulmonary damage.

Animals↗

PubMed1995

Ferrous ion strongly promotes the ring opening of the hydrolysis intermediates of the antioxidant cardioprotective agent dexrazoxane (ICRF-187).

The ferrous- and ferric-ion-promoted hydrolysis of the doxorubicin cardioprotective agent dexrazoxane (ICRF-187) has been studied spectrophotometrically and by HPLC. While dexrazoxane itself did not undergo any iron-promoted ring-opening hydrolysis, both ferrous (t1/2 0.4 min) and ferric (t1/2 170 min) ions promoted, by factors of up to 6000 and 8, respectively, the hydrolysis of the one-ring open intermediates of dexrazoxane to yield the strongly metal-ion-chelating form. The pH dependence of both the ferrous- and ferric-ion-promoted hydrolysis of one of the one-ring open intermediates was studied and was consistent with base-catalyzed hydrolysis. In each case, due to the problem of proton ambiguity in the rate law, a bimolecular reaction with external hydroxide could not be distinguished from an intramolecular reaction of hydroxide bound to iron. The mechanism of the cardioprotective effects of dexrazoxane may involve enzymatic or nonenzymatic hydrolysis to the one-ring open intermediates. Thus, these intermediates may be the active forms of the drug that may be acting by either displacing iron from the iron-doxorubicin complex or chelating loosely bound iron and then undergoing a rapid metal-ion-promoted hydrolysis to their strongly chelating forms. Thus, the ability of iron to participate in site-specific hydroxyl radical damage may be reduced.

Chromatography, High Pressure Liquid↗

PubMed1995

Doxorubicin reduces the iron(III) complexes of the hydrolysis products of the antioxidant cardioprotective agent dexrazoxane (ICRF-187) and produces hydroxyl radicals.

Dexrazoxane (ICRF-187) is very effective in protecting against doxorubicin-induced cardiotoxicity. Dexrazoxane likely acts though its metal ion binding hydrolysis product ADR-925 by reducing doxorubicin-promoted iron-based oxygen-free radical damage. In this study we show that doxorubicin and epirubicin (but not daunorubicin, idarubicin, or mitoxantrone) are able to reduce iron(III)-ADR-925 and under aerobic conditions are able to produce hydroxyl radicals that are detectable by EPR spin trapping. The ability of iron(III)-ADR-925 to produce hydroxyl radicals in the presence of anthraquinones is compared with that of other ferric chelates, including those of the one-ring open hydrolysis intermediates of dexrazoxane, the tetraacid derivative of ADR-925, EDTA, DTPA, and deferoxamine. The anthraquinones that lacked an alpha-ketol side chain (daunorubicin, idarubicin, and mitoxantrone) produced much less hydroxyl radical than those that did (doxorubicin and epirubicin). The model alpha-ketol, dihydroxyacetone, was also able to promote the formation of hydroxyl radicals in the presence of iron(III) chelates. Since dexrazoxane and doxorubicin are administered together, the possibility must be considered that anthracyclines with alpha-ketol side chains may be oxidized by iron(III)-ADR-925, thus changing their antitumor activity.

Aerobiosis↗

PubMed1995

NADPH-cytochrome-P450 reductase promotes hydroxyl radical production by the iron complex of ADR-925, the hydrolysis product of ICRF-187 (dexrazoxane).

ICRF-187 (dexrazoxane) is currently in clinical trials as a cardioprotective agent for the prevention of doxorubicin-induced cardiotoxicity. ICRF-187 likely acts through its strongly metal ion-binding rings-opened hydrolysis product ADR-925 by removing iron from its complex with doxorubicin or by chelating free iron. The ability of NADPH-cytochrome-P450 reductase to promote hydroxyl radical formation by iron complexes of ADR-925 and EDTA was compared by EPR spin trapping. The iron-EDTA complex produced hydroxyl radicals at six times the rate that the iron-ADR-925 complex did. The aerobic oxidation of ferrous complexes of ADR-925, its tetraacid analog, EDTA and DTPA was followed spectrophotometrically. The iron(II)-ADR-925 complex was aerobically oxidized 700 times slower than was the EDTA complex. It is concluded that even though ADR-925 does not completely eliminate iron-based hydroxyl radical production, it likely protects by preventing site-specific hydroxyl radical damage by the iron-doxorubicin complex.

Animals↗

PubMed1994

Quantitation of the dexrazoxane hydrolysis product ADR-925 by fluorescence detection of its terbium(III) complex after high-performance liquid chromatographic separation.

An HPLC fluorescence detection method was developed to quantitate the complexing agent ADR-925 (II). Compound II is the metal-ion-binding rings-opened hydrolysis product of the doxorubicin cardioprotective drug dexrazoxane (I). II formed a strong complex with the fluorescent metal-ion terbium(III) and this complex could be chromatographed by HPLC and detected by its fluorescence, with excitation and emission wavelengths of 200 and 544 nm, respectively. The terbium(III)-II complex was separated isocratically on a C18 reversed-phase column with an eluent consisting of 50% methanol and 50% 4 mM aqueous solution of the ion-pairing reagent 1-heptanesulfonate. The lower limit of detection of II, quantitated as its fluorescent terbium(III) complex, was estimated to be 25 pmol, which was some twenty times lower than with UV-Vis absorbance detection. The fluorescent detection method was used to follow the hydrolysis of I to II in buffer and in blood plasma.

Chelating Agents↗

PubMed1994

Stereoselective hydrolysis of ICRF-187 (dexrazoxane) and ICRF-186 by dihydropyrimidine amidohydrolase.

The enzymatic ring-opening hydrolyses of the doxorubicin cardioprotective agents (+)-(S)-ICRF-187 (dexrazoxane), (-)-(R)-ICRF-186, and rac-ICRF-159 by the enzyme dihydropyrimidine amidohydrolase (DHPase) have been studied. ICRF-187 underwent enzymatic ring-opening hydrolysis by DHPase 4.5 times faster than did ICRF-186. It was also shown that DHPase opens only one ring of ICRF-186 and does not act on this one-ring open hydrolysis product, as has been observed for ICRF-187. Differences in the rates at which the two optical isomers are acted upon by DHPase suggest that they could have differing protective effects.

Amidohydrolases↗

PubMed1994

Pharmacodynamics of the hydrolysis-activation of the cardioprotective agent (+)-1,2-bis(3,5-dioxopiperazinyl-1-yl)propane.

The hydrolysis of the cardioprotective agent ICRF-187 [(+)-1,2-bis(3,5-dioxopiperazinyl-1-yl)propane] to its presumed active form under conditions of physiologic pH and temperature were followed by HPLC chromatography. Successful chromatography of all of the hydrolysis products required the use of EDTA in the aqueous eluant to prevent metals in the HPLC flow system from binding to the strongly metal ion-binding product ADR-925. The kinetics of the hydrolysis was followed to approximately 200 h. The ring closest to the methyl group on ICRF-187 was observed to open at about twice the rate of the other ring. This product accumulates in the reaction mixture not only because it is produced more quickly but also because it decays more slowly. ICRF-187 is lost from the reaction mixture with a half-life of 9.3 h, whereas the final hydrolysis product ADR-925 is produced with a half-life of 23.0 h. Rate constants for ring opening to one-ring and two-ring opened hydrolysis products were obtained with a reaction scheme that assumed parallel and consecutive first-order reactions for these steps.

Biotransformation↗