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Quinacrine sterilization (QS) is a nonsurgical female method used by more than 175,000 women in over 50 countries. With FDA approval, QS is expected to be used by hundreds of millions of women. The negative international health consequences of the results of a 2-year rat study in 2010 by Cancel et al. in Regulatory Toxicology and Pharmacology (RTP) (56:156-165) are incalculable. S1C(R2) was ignored in this study, including the fundamental concept of maximum tolerated dose (MTD), which resulted in the use of massive doses (up to 35 times the MTD) which killed many of the rats and destroyed the uterus of survivors. The design of this rat study was built on the false assertion that this study mimics what happens in women. Cancel et al. (2010), concludes it "seems most likely" that genotoxicity was a major factor in the carcinogenicity observed, prompting the FDA to halt further research of QS. In RTP, McConnell et al. (2010), and Haseman et al. (2015), using the authors' data, definitively determined the carcinogenicity to be secondary to necrosis and chronic inflammation. Decisions made in the design, conduct, analysis, interpretation and reporting in this study lack scientific foundation. This paper explores these decisions., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Arginine auxotrophy constitutes the Achilles' heel for several tumors, among them glioblastoma multiforme (GBM). Hence, arginine-depleting enzymes such as arginine deiminase (ADI) from Streptococcus pyogenes are promising for treatment of primary and maybe even refractory GBM. Based on our previous study in which ADI-susceptibility was shown on a panel of patient-derived GBM cell lines, we here aimed at deciphering underlying molecular mechanisms of ADI-mediated growth inhibition. We found that ADI (35 mU/mL) initially induces a cellular stress-response that is characterized by upregulation of genes primarily belonging to the heat-shock protein family. In addition to autophagocytosis, we show for the first time that senescence constitutes another cellular response mechanism upon ADI-treatment and that this bacterial enzyme is able to act as radiosensitizer (¼ cases). Long-term treatment schedules revealed no resistance development, with treated cells showing morphological signs of cell stress. Next, several combination strategies were employed to optimize ADI-based treatment. Simultaneous and sequential S. pyogenes ADI-based combinations included substances acting at different molecular pathways (curcumin, resveratrol, quinacrine, and sorafenib, 2 × 72 h treatment). Adding drugs to GBM cell lines (n = 4, including a matched pair of primary and recurrent GBM in one case) accelerated and potentiated ADI-mediated cytotoxicity. Autophagy was identified as the main cause of tumor growth inhibition. Of note, residual cells again showed classical signs of senescence in most combinations. Our results suggest an alternative treatment regimen for this fatal cancer type which circumvents many of the traditional barriers. Using the metabolic defect in GBM thus warrants further (pre-) clinical evaluation., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Quinacrine, which is clinically used as an antimalarial drug, has anti-cancer activity. However, mechanism underlying its cytotoxic effect remains to be completely elucidated. In the present study, we investigated the cytotoxic effect of quinacrine on human leukemia U937 cells. Quinacrine-induced apoptosis of U937 cells was accompanied with ROS generation, mitochondrial depolarization, and BAX upregulation. Quinacrine-treated U937 cells showed ROS-mediated p38 MAPK activation and ERK inactivation, which in turn upregulated FOXP3 transcription. FOXP3-mediated miR-183 expression decreased β-TrCP mRNA stability and suppressed β-TrCP-mediated SP1 degradation, thus increasing SP1 expression in U937 cells. Upregulated SP1 expression further increased BAX expression. BAX knock-down attenuated quinacrine-induced mitochondrial depolarization and increased the viability of quinacrine-treated cells. Together, our data indicate that quinacrine-induced apoptosis of U937 cells is mediated by mitochondrial alterations triggered by FOXP3/miR-183/β-TrCP/SP1 axis-mediated BAX upregulation., (Copyright © 2017 Elsevier Inc. All rights reserved.)

A rat carcinogenicity bioassay (CaBio) of quinacrine was reanalyzed to investigate its mode of tumor induction. Quinacrine's effects in the rat uterus when administered as a slurry in methylcellulose were contrasted with the human clinical experience which uses a solid form of the drug, to determine the relevance of the tumors produced in the rat to safe clinical use of quinacrine for permanent contraception (QS). A review was performed of the study report, dose feasibility studies, and clinical evaluations of women who had undergone the QS procedure. The top three doses of quinacrine in the CaBio exceeded the maximum tolerated dose, and produced chronic damage, including inflammation, resulting in reproductive tract tumors. Chronic inflammation was significantly correlated with the tumors; there was no evidence of treatment-related tumors in animals without chronic inflammation or other reproductive system toxicity. Because such permanent uterine damage and chronic toxicity have not been observed in humans under therapeutic conditions, we conclude that this mode of action for tumor production will not occur at clinically relevant doses in women who choose quinacrine for permanent contraception., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

Although quinacrine dihydrochloride dihydrate is a widely used drug substance, a comprehensive determination of its stability profile is lacking. In this work, an integrative approach is implemented to determine the drug stability both in the solid state and aqueous solutions, identify the impurities that can be found in the active pharmaceutical ingredient, and evaluate the associated toxicity risks. Thermal analyses pointed out a two-step dehydration of the solid state. This phenomenon seems to be consistent with the organization of the water molecules in the crystal structure and results in the destruction of the lattice. Seven related compounds of quinacrine have been identified by liquid chromatography-ion trap mass spectrometry. The main thermal degradant both in the solid state and the solution corresponds to the N-deethyl compound, whereas quinacrine tertiary amine oxyde appears to be a signal impurity of oxidative stress in solution. Moreover, two photolytic impurities can be formed in solution either by aromatic amine cleavage or via O-demethylation. Additionally, using computational approaches, the analysis of the potential toxicity of the impurities compared with the parent compound one shows that ketone and O-demethyl derivatives may exhibit specific toxicity profiles., (Copyright © 2011 Wiley-Liss, Inc.)

Gold nanoparticles coated with oppositely charged polyelectrolytes, such as polyallylamine hydrochloride and polystyrenesulfonate, were examined for potential inhibition of prion protein aggregation and prion (PrPSc) conversion and replication. Different coatings, finishing with a positive or negative layer, were tested, and different numbers of layers were investigated for their ability to interact and reduce the accumulation of PrPSc in scrapie prion infected ScGT1 and ScN2a cells. The particles efficiently hampered the accumulation of PrPSc in ScN2a cells and showed curing effects on ScGT1 cells with a nanoparticle concentration in the picomolar range. Finally, incubation periods of prion-infected mice treated with nanomolar concentrations of gold nanoparticles were significantly longer compared to untreated controls.

The in vitro micronucleus assay has been extensively used as an in vitro screening tool to identify test articles that might have aneugenic or clastogenic potential. Currently, the Organization for Economic Co-operation and Development (OECD) is working towards a final version of the guideline for the conduct of the in vitro mammalian cell micronucleus Test (MNvit). A few questions regarding appropriate cytotoxicity measurements and cytotoxicity limits to use remain to be answered. In order to resolve the remaining questions, we compared the induction of micronuclei at the top dose (50-60% cytotoxicity) determined by either Relative Cell Counts (RCC), Relative Increase in Cell Counts (RICC), Relative Population Doublings (RPD), or Cytokinesis-Blocked Proliferating Index (CBPI) using weak and strong inducers of micronuclei in both the presence and absence of cytochalasin B (CYB) in Chinese hamster ovary (CHO) and human lymphoblastoid TK6 cells. In order to assess extensive dose-response relationships, we selected expected weak (diazepam, phenolphthalein, quinacrine dihydrochloride dihydrate) and strong (cytosine arabinoside, mitomycin C, vinblastine sulphate) inducers of micronuclei with a variety of different mechanisms of action for testing. The results clearly demonstrated that all six compounds produced positive responses using either cytotoxicity measurement. The outcome from these studies further supports the cytotoxicity measurements and cytotoxicity limits proposed in the draft OECD guideline., (Copyright © 2010 Elsevier B.V. All rights reserved.)

This study investigated if quinacrine can induce a tumorigenic response in rats when administered in a manner similar to the intended human use for female non-surgical sterilization. Young sexually mature female rats received two doses of quinacrine (or 1% methylcellulose control) into each uterine horn approximately 21 days apart, and were observed for 23 months after the second dose administration. Dose levels were 0/0, 0/0, 10/10, 70/70, and 70/250-350 mg/kg (first dose/second dose), which represent local doses in the uterus at approximate multiples of 1x, 8x and 40x the human dose (mg quinacrine/g uterine weight) used for female non-surgical sterilization. Rats were observed for viability, clinical signs of toxicity, and changes in body weight and food consumption. At necropsy, selected organs were weighed, macroscopic observations were recorded, and tissues were collected, fixed, processed, and examined for microscopic pathologic findings. Acute quinacrine toxicity was evident during the dosing period but did not affect long-term survival. Non-neoplastic findings were more common in treated animals than controls, providing evidence of the appropriateness of the bioassay. The incidence of uncommon tumors of the reproductive tract was similar to controls at doses of 10/10mg/kg but increased with dose level and was significantly greater than controls at >or=70/70 mg/kg. We conclude that two doses of quinacrine administered approximately 21 days apart into the uterus of young sexually mature rats at a local dose approximately 8 times the human dose used for non-surgical female sterilization increased the lifetime risk of tumor development in the reproductive tract., ((c) 2009 Elsevier Inc. All rights reserved.)

This companion article offers an alternative interpretation for the quinacrine-induced uterine tumors observed in a 2-year bioassay in rats (CaBio, Cancel et al., 2010), and provides additional data from two new experiments that support a different interpretation and analysis. Our major premise is that the design of the Cancel et al. bioassay was flawed, particularly regarding dose selection that allowed for misinterpretation of carcinogenic activity. We feel the totality of the information provided herein dictates that the doses (70/70, 70/250 and 70/350 mg/kg quinacrine) causing uterine tumors in their study clearly exceeded the maximum tolerated dose (MTD) typically administered in chronic cancer studies. Our new data support this conclusion and serve to explain the development of lesions, especially the uterine tumors, they have reported. We argue that the rat uterus is not a valid surrogate for the human fallopian tube. Further, we maintain that quinacrine is not genotoxic in vivo, as suggested in their paper. In summary, we believe that quinacrine is not carcinogenic in rats at doses that do not exceed the MTD., ((c) 2010 Elsevier Inc. All rights reserved.)

Adaptive response (AR) is a well-documented phenomenon by which cells or organisms exposed to low dose of a genotoxicant become less sensitive to subsequent high-dose exposure to the same or another genotoxicant. AR, if induced can modify the efficacy leading to drug or radio-resistance, during anti-neoplastic drug or radiation treatment. Contradictions exist in AR induction by different genotoxicants with respect to the biomarkers, time schedules, and inter-individual variability, reflecting the complexity of AR in eukaryotic cells. In order to further ascertain these factors, AR induced by anti-neoplastic agents mitomycin C (MMC), bleomycin (BLM) and chemosterilant quinacrine dihydrochloride was examined in different donors and time schedules using cytogenetic biomarkers chromosome aberrations, sister chromatid exchanges and micronuclei (MN). BLM- and hyperthermia (HT)-induced cross-resistance to gamma rays and MMC/BLM, respectively, was also studied. Difference between MMC- and BLM-induced protective effects in biomarkers examined in the same donors was noticed. Adaptation to BLM and HT showed cross-resistance to chromosome damage induction by gamma rays and BLM/MMC, respectively. Cell cycle analysis indicated that adaptation is not caused by change in the rate of cell proliferation after challenge dose. MN as a chromosomal biomarker in large-scale population studies on AR is advocated, based on similar AR induced in all donors by MMC/BLM and rapid assessment in binucleated cells. Influence of certain genotypes on chromosomal biomarkers used in AR studies and role of AR in radiation and chemotherapy need to be further deciphered.

Quinacrine is an acridine derivative under investigation for its use in nonsurgical female sterilization. Safety issues regarding the carcinogenic potential of quinacrine have been raised because it is mutagenic and clastogenic in vitro. The objective of the study was to evaluate the carcinogenic potential of quinacrine dihydrochloride (quinacrine) in neonatal mice treated with single intraperitoneal doses on postpartum days 8 and 15 and observed for 52 weeks. Neonatal Crl: CD-1 mice of each sex were randomly allocated into four treatment groups (0, 10, 50, and 150 mg/kg), dosed twice with quinacrine suspended in carboxymethylcellulose, observed for 52 weeks post dose, and then euthanized, necropsied, and subjected to a full histopathological examination. In male mice, tumor incidence was not significantly increased at any site at any dose level. In female mice, the incidence of benign uterine endometrial stromal polyps was slightly greater at the mid and high dose (> or = 50 mg/kg), as was the incidence of endometrial hyperplasia. The incidence of polyps in these groups was not significantly greater than in controls by pair-wise comparison but was significantly greater (p = .042) by the linear trend test. The authors conclude that quinacrine administered twice to neonatal mice may have enhanced or accelerated the development of endometrial hyperplasia and uterine stromal polyps at higher doses. Because uterine stromal polyps are a commonly observed benign tumor in older mice, the significance of this finding is unclear and will require a weight of evidence evaluation for a conclusion on the carcinogenic potential of quinacrine.

1. Recent publication has suggested that quinacrine may be a candidate for treatment of Creutzfeldt-Jakob disease (CJD). But serious toxicity of quinacrine to liver and hematological system has been reported. 2. We disclosed the permeability of quinacrine can be enhanced by presence of p-glycoprotein inhibitor at blood-brain barrier in vitro. Therefore, we tried the protocol of combination of quinacrine and p-glycoprotein inhibitor, verapamil for patients with CJD. 3. When compared clinical effects by quinacrine and the combination therapy, improvement of clinical findings was observed at the same level without any adverse effects. Low-dose quinacrine with verapamil can be used as safe treatment of CJD.

This article describes the results of a combined photophysical and photobiological study aimed at understanding the phototoxicity mechanism of the antimalarial drugs quinine (Q), quinacrine (QC) and mefloquine (MQ). Photophysical experiments were carried out in aqueous solutions by stationary and time-resolved fluorimetry and by laser flash photolysis to obtain information on the various decay pathways of the excited states of the drugs and on transient species formed on irradiation. The results obtained showed that fluorescence and intersystem crossing account for all the adsorbed quanta for Q and MQ (quantum yield of about 0.1 and 0.9, respectively) and only for 24% in the case of QC, which has a negligible fluorescence quantum yield (0.001). Laser flash photolysis experiments evidenced, for QC and MQ, the occurrence of photoionization processes leading to the formation of the radical cations of the drugs. The effects of tryptophan and histidine on the excited states and transient species of the three drugs were also investigated. In parallel, the photoactivity of the antimalarial drugs was investigated under UV irradiation on various biological targets through a series of in vitro assays in the presence and in the absence of oxygen. Phototoxicity on 3T3 cultured fibroblasts and lipid photoperoxidation were observed for all the drugs. The photodamage produced by the drugs was also evaluated on proteins by measuring the photosensitized cross-linking of spectrin. The combined approaches were proven to be useful for understanding the mechanism of phototoxicity induced by the antimalarial drugs.

The frameshift mutagenicity of 9-aminoacridine (9AA) was compared with that of quinacrine, the acridine mustards ICR-191 and quinacrine mustard (QM), and the nitroacridine Entozon in the lacZ reversion assay in Escherichia coli. As intercalating agents, 9AA and quinacrine cause mutations through noncovalent associations with DNA. Mustards and nitroacridines form covalent adducts in DNA and give rise to different spectra of mutations. Quinacrine and 9AA most effectively induced -1 frameshifts in a run of guanine residues, with 9AA being the more potent mutagen. They also induced +G frameshifts. The acridine mustard ICR-191 was a stronger mutagen than 9AA, owing largely to its potent induction of +G frameshifts. QM induced +G frameshifts more strongly than did its nonreactive counterpart quinacrine. The nitroacridine Entozon differed from the other acridines in being a potent inducer of -2 frameshifts, but it was less effective in inducing +/-1 frameshifts. Quinacrine, although a simple intercalator, induced all five kinds of frameshift mutations detected in the assay, as did the acridine mustards. Although +A and -A frameshifts were induced, adenine runs were less susceptible to acridine mutagenesis than guanine runs. The patterns of frameshift mutagenicity in the lacZ assay are similar to those in an assay based on the reversion of mutations in the tetracycline-resistance gene of the plasmid pBR322. The similarity suggests that the responses reflect the inherent bacterial mutagenicity of the compounds in the local sequence context and are not highly dependent on the broader sequence context. The results are interpreted with respect to slipped mispairing models of frameshift mutagenesis., (Copyright 2003 Wiley-Liss, Inc.)

Clastogenicity is frequently observed following treatment of mammalian cells with new chemical entities. This clastogenicity, unless proven otherwise, is assumed to result from the imperfect repair of DNA lesions produced from covalent chemical/DNA interaction. However, clastogenicity can also arise via other mechanisms such as non-covalent chemical intercalation into DNA resulting in poisoning of cellular DNA topoisomerase II (topo II) and stabilization of DNA double strand breaks. We have recently reported modifications to the V79 in vitro micronucleus assay which allow an indirect evaluation of both the intercalative and topoisomerase-interactive activities of chemical agents. In the present studies we have used these modified assays to further assess the validity of this approach in an evaluation of a number of intercalating and non-intercalating polycyclic compounds. It is shown that intercalating agents may be catalytic topo II inhibitors (e.g. chloroquine (CHL), tacrine (TAC), 9-aminoacridine (9AA), ethidium bromide (EB)) or topo II poisons (e.g. proflavine (PROF), auramine O (AUR) and curcumin (CURC)). Still other intercalators are shown to lack detectable topo II-interactions, (e.g. imipramine (IMP), quinacrine (QUIN), 2-aminoanthracene (AA), iminostilbene (IMN) and promethazine (PHE)). It is concluded that (1) the clastogenicity of three agents, PROF (a typical DNA intercalating agent), and AUR and CURC (both structurally atypical intercalating agents, with unknown clastogenic mechanisms), may be due to topo II poisoning; (2) other intercalating agents may either act as catalytic topo II inhibitors or exhibit no functional topo II interaction; (3) The use of these cell-based approaches may provide a logical first step in determining if unexpected clastogenicity associated with test article exposure is due to a topo II interaction.

Quinacrine has been used for voluntary female non-surgical sterilization for its ability to produce tubal occlusion. Safety issues regarding quinacrine have been raised because it has been shown to intercalate with DNA. Therefore, safety issues need to be resolved by appropriate toxicology studies to support a review for human transcervical use. Such toxicology studies include mutagenicity assays. Here we report an evaluation of the genotoxicity of quinacrine dihydrochloride dihydrate (QH) using a battery of assays. In the bacterial mutagenicity assay, QH was strongly positive in Salmonella typhimurium tester strain TA1537 with and without S9-activation and in S. typhimurium tester strain TA98 with S9-activation; QH was also strongly positive in Escherichia coli WP2 uvrA without S9-activation. QH was not mutagenic in S. typhimurium tester strains TA100 and TA1535 with and without S9-activation. QH was mutagenic in the mouse lymphoma assay in the absence of S9-activation. QH was clastogenic in Chinese hamster ovary (CHO) cells, with and without S9-activation. QH was negative for polyploidy in the same chromosome aberration test. Using a triple intraperitoneal injection treatment protocol in both male and female mice, QH was negative in the in vivo mouse micronucleated erythrocyte (micronucleus) assay. These results confirm that QH is mutagenic and clastogenic in vitro and suggest a potential risk to human health due to QH exposure after intrauterine exposure.

The intrauterine installation of quinacrine represents a simple, inexpensive, effective, and seemingly safe method of non-surgical female sterilization. Existing clinical data on its use are very encouraging: Results of a large study conducted in Vietnam with an overall sample of over 30,000 women showed high effectiveness; in addition, when a retrospective study was conducted in these women, cumulative 5-year pregnancy rates were estimated to be 13% in women younger than 35 years and 6.8% in the women older than 35. Overall, failure rates with quinacrine have been estimated, at 10 years, to be between 1.9 and 4 times higher than those obtainable with conventional surgical procedures of tubal interruption. Unfortunately, existing toxicology for topical use of quinacrine pellets is incomplete. This prompted an expert group convened by WHO, to comment, in 1994, that the toxicology of locally applied quinacrine is inadequate. To counter this statement the proponents of the method argue that it is unfair to apply the stringent pre-clinical requirements that are mandatory in the industrialized world, to methods utilized in countries plagued by both high fertility and high maternal mortality. This controversy will soon be resolved since conventional toxicological evaluation is now underway. In conclusion, the future of quinacrine for non-surgical female sterilization will depend on the results of long-term animal studies, as well as the retrospective human studies now being carried out.

Quinacrine and chloroquine, two widely used antimalarials, bind strongly to deoxyribonucleic acid, thus preventing mutagenesis. We studied a possible chemoprotective effect of these substances on carcinogenesis of the nervous system induced in Wistar rats by transplacental administration of ethylnitrosourea. One experimental group consisted of rats born from mothers treated with quinacrine prior to prenatal exposure to ethylnitrosourea; a second group consisted of rats chronically treated with chloroquine after prenatal exposure to ethylnitrosourea. When compared with controls, no significant differences were observed in tumor incidence. However, early tumor growth was observed in both rats treated with quinacrine (P < 0.0004) and rats treated with chloroquine (P < 0.02). These differences were due mostly to rapid development of ependymomas of the spinal cord. Our results suggest that quinacrine and chloroquine do not prevent the structural alterations induced in DNA by ethylnitrosourea, which lead, in the long term, to a high incidence of neoplasms in the nervous system. Moreover, the antimalarials studied seem to promote the carcinogenic effects of ethylnitrosourea on ependymal cells.

Objective: To compare the efficacies of erythromycin and quinacrine for nonsurgical sterilization in rats. Quinacrine used for nonsurgical sterilization in women is mutagenic, and most clinical regimens have had a higher failure rate than surgical sterilization., Design: This acute mammal study included five groups of rats assigned randomly and evaluated at two times after treatment., Animal(s): Adult female Sprague-Dawley rats., Intervention(s): Five groups of female Sprague-Dawley rats (20 per group) were given 70 or 280 mg/kg of erythromycin lactobionate, 350 mg/kg of quinacrine hydrochloride, or vehicle control administered transcervically. Rats were mated 21 days later. Additional groups (n = 4 per group) were treated and killed 21 days later without mating., Main Outcome Measure(s): Fourteen days after mating, numbers of ovarian corpora lutea, total uterine implants, and embryos were evaluated. For unmated animals, uterine sections were examined for fibrosis and lumen closure., Result(s): Neither drug altered numbers of corpora lutea. Erythromycin decreased pregnancy rate and number of implantations (increased preimplantation loss) in a dose-related fashion. Quinacrine increased resorptions. Uterine pathology was more extensive and frequent in erythromycin-treated animals, with extent and severity increasing from 21 to 35+ days., Conclusion(s): Erythromycin was more effective than quinacrine in preventing pregnancy.

Maitotoxin (MTX), a putative Ca(2+) channel activator produced by the dinoflagellate Gambierdiscus toxicus showed extremely potent hemolytic and ichthyotoxic activities. Hemolysis of 1% mouse blood cell suspension in saline occurred at 15 nM of MTX. The activity was enhanced six-fold in the presence of 10 microM of Ca(2+) and completely blocked by EDTA2Na, indicating its dependency on external Ca(2+). The MTX-induced hemolysis was little affected by L-type Ca(2+) channel blockers (diltiazem, nifedipine, verapamil) but was strongly inhibited by calmodulin blockers (prenylamine and chlorpromazine) or a phospholipase A2 inhibitor (quinacrine). MTX was mimicked by a calcium ionophore, calcimycin. Based on these results, a series of cellular events triggered by MTX were presumed to occur in the following sequence: increased Ca(2+) entry in cells, activation of calmodulin, promotion of phospholipase A2 activity, and finally destruction of cell membrane resulting from hydrolysis of membrane lipids. The sensitivity of blood cells to MTX varied significantly, dependent on the animal sources. Nucleated blood cells of carps and chickens were 100 times more resistant than those of mammals. LC(50) of MTX to freshwater fish Tanichthys albonubes in Ca(2+) free media (pH 8) was 5 nM but was markedly lowered to 3 pM by raising pH to 8 and increasing Ca(2+) concentration to 2 mM. In a marine environment MTX was 2000 times more toxic to fish than 42-di-hydrobrevetoxin-B (PbTx-3), one of the best known ichthyotoxins of red-tide origins., (Copyright 1999 John Wiley & Sons, Ltd.)

The modifying effects of quinacrine administration during the post-initiation phase of carcinogenesis were investigated in hamsters treated with N-nitrosobis(2-oxopropyl)amine (BOP). Female Syrian hamsters were given three weekly s.c. injections of BOP at a dose of 10 mg/kg and then 300 or 100 ppm quinacrine in their diet for 37 weeks. Additional groups of animals received the BOP injection alone, or only the 300 ppm quinacrine treatment as BOP-negative controls. At week 40 of the experiment, all surviving animals were killed and development of proliferative lesions was assessed histopathologically. The multiplicity of pancreatic adenocarcinomas and dysplastic lesions per hamster was significantly higher (P<0.01 and P<0.05) in the BOP/Q100 group (1.92 and 1.78) than in the BOP-alone group (1.07 and 0.79). The incidence of hepatocellular adenomas plus carcinomas was also significantly elevated (P<0.05) in the BOP/Q300 and BOP/Q100 groups. In contrast, the multiplicity of lung adenomas plus adenocarcinomas was significantly decreased (P<0.05) by the Q300 treatment. Neither the incidence nor the multiplicity of renal cell tumors (adenomas and carcinomas) or nephroblastomas significantly differed between the BOP-treated groups. Electron microscopic examination revealed an abundance of myeloid lamellar bodies filling the cytoplasm of hepatocytes and pancreatic ductular and acinar cells, and epithelial cells of the gallbladder in the quinacrine-treated animals, the degree being dose-dependent. Our results indicate that quinacrine enhances pancreatic and hepatic carcinogenesis in hamsters induced by BOP.

The antimalarial agents quinacrine and chloroquine are well known as potent inducers of lysosomal storage of polar lipids (lipidosis) in cell culture and in vivo. In previous experiments on cultured fibroblasts, chloroquine was shown to additionally cause weak lysosomal storage of sulphated glycosaminoglycans (GAGs) thus inducing mucopolysaccharidosis (MPS). In the present study, quinacrine was investigated for this ability, because we wished to know whether or not the acridine ring system in quinacrine would enhance the MPS-inducing potency as compared to chloroquine carrying an isoquinoline ring system. Tilorone (2,7-bis[2-(diethylamino)ethoxy]fluoren-9-one) known as a potent inducer of MPS served as reference compound. The compounds were compared at a concentration (3 microM) which did not enhance the secretion of the lysosomal enzyme beta-hexosaminidase (E.C. 3.2.1.52), since this would be an indication of unspecific drug effects upon the endosomal/lysosomal compartments of the cell. Additionally the liver of quinacrine- and chloroquine-treated rats was examined with the question whether the lysosomal GAG storage induced by either drug in cell culture had an equivalent in intact organisms. Both, in cell culture and in vivo, quinacrine was found to be a more potent inducer of lysosomal GAG storage than was chloroquine. The results suggest that the acridine ring system favours this drug side effect as compared with the bicyclic isoquinoline ring system. On the other hand, quinacrine was significantly less potent than tilorone and the Symmetrically substituted acridine derivative 3,6-bis[2-(diethylamino)ethoxy]acridine investigated previously. This suggests that the asymmetric structure of the quinacrine molecule reduces the potency as compared to the symmetrically substituted bisbasic compounds with planary tricyclic ring systems such as tilorone and congeners.

Quinacrine resistance has been induced in 3 Giardia duodenalis laboratory stocks and 4 lines resistant to other drugs. The quinacrine-resistant lines were maintained in normally lethal levels of 5 microM quinacrine and some lines are viable in 20 microM levels of the drug. Fluorescence studies indicated that quinacrine was taken up by sensitive cells but was actively excluded from resistant trophozoites. The nuclei were not a site of drug accumulation and no specific fluorescence in the trophozoite could be attributed to any structure. Blebs of concentrated drug appeared prior to disintegration of the membrane of drug-sensitive trophozoites exposed to drug overnight. Parasite lines already resistant to furazolidone adapted more readily to quinacrine exposure than drug-sensitive stocks. This multiple drug resistant phenotype was not as marked with metronidazole-resistant lines.

The functional effects of chronic administration of 60 mg kg-1 chloroquine or quinacrine given as daily intraperitoneal injections for 84 days on normal and denervated expansor secundariorum muscles, a smooth muscle from the wing of chicks wholly innervated by noradrenergic nerves, have been investigated. Administration of quinacrine, but not chloroquine, blocked responses to noradrenergic nerve stimulation. Surgical denervation abolished responses to nerve stimulation. Contraction of the expansor muscle induced by noradrenaline was not changed by chronic administration of chloroquine or quinacrine, and both drugs did not influence denervation supersensitivity of expansor muscles to noradrenaline. Expansor muscles were unresponsive to acetylcholine (ACh) and histamine, but muscles from chicks chronically treated with chloroquine and quinacrine were responsive to ACh and histamine. Denervation also restored the response of expansor muscles to ACh and histamine and the responses were greater for denervated muscles from chronically treated chicks; these changes were more marked with quinacrine. Expansor muscles were contracted by potassium chloride (KCl) and 5-hydroxytryptamine (5-HT), and chronic treatment increased the responsiveness of expansor muscles to KCl. Denervation increased the responsiveness of expansor muscles to KCl and 5-HT; this effect was more pronounced in denervated muscles from quinacrine-treated chicks. The findings indicate that chronic administration of quinacrine sensitizes smooth muscles to agonist drugs by blocking noradrenergic transmission to induce postjunctional changes and exerting a direct action on the smooth muscle; these actions are less pronounced with chloroquine administration.

The functional effects on chick smooth and skeletal muscle of chronic administration of 60 mg kg-1 chloroquine or quinacrine given as daily intraperitoneal injections for 70 days have been investigated. Noradrenaline and potassium chloride (KCl) contracted the normal expansor secundariorum muscle, a smooth muscle from the wing of chicks wholly innervated by noradrenergic nerves. The muscle was unresponsive to acetylcholine and histamine. Chronic administration of chloroquine or quinacrine induced supersensitivity of expansor muscles to KCl and the muscles were contracted by acetylcholine and histamine. These actions were more pronounced in quinacrine-treated chicks and could be due to direct smooth muscle sensitization that may result in postjunctional changes. The oesophagus is a smooth muscle that is predominantly under parasympathetic control. The oesophagus from chronically-treated chicks was more sensitive to acetylcholine and KCl than the control muscles. This sensitization was more marked for chloroquine than quinacrine. Chronic administration of chloroquine and quinacrine depressed skeletal muscle contractions evoked by acetylcholine and potassium chloride. These findings indicate that chronic chloroquine and quinacrine administration sensitise smooth muscle to agonist drugs but depress neuromuscular transmission.

The purpose of this study was to investigate whether generalized lipidosis experimentally induced by cationic amphiphilic drugs in rats is regularly associated with lipidotic alterations in the cornea. After chronic oral treatment with chlorphentermine, iprindole, or tamoxifen all animals showed clear lipidosis-like alterations in corneal cells. After chronic oral treatment with chloroquine and quinacrine the results were variable and unpredictable; however, consistent lipidosis-like alterations were found when chloroquine was applied locally onto the cornea. The present results show that basically the cornea of rats is involved in drug-induced lipidosis. For toxicological studies it must be kept in mind, however, that the reactions of rat cornea may be unreliable and less marked than in the cornea of human beings.

To extend the data on the mutagenic effects of intercalating agents in Drosophila melanogaster, chloroquine and quinacrine were tested for the induction of genetic damage in D. melanogaster males. Sex-linked recessive lethals and sex-chromosome loss induction were studied following treatment of adult males using a feeding technique. Our results show that both intercalating compounds increase significantly the frequency of sex-linked recessive lethals, but are unable to induce sex-chromosome loss in male germ cells under the conditions of testing.

Quinacrine hydrochloride is toxic for the heart of F-344 rats. Rats treated with 500 ppm quinacrine hydrochloride in the diet all developed a high incidence of left atrial thrombosis. The lesion was associated with cardiac hypertrophy and dilatation and focal myocardial degeneration. Rats died from cardiac hypertrophy with severe acute and chronic congestion of the lungs, liver, and other organs. Seventy percent of rats given 250 ppm quinacrine hydrochloride and 1,000 ppm sodium nitrite simultaneously in the diet had thrombosis of the atria of the heart, while untreated control rats in this laboratory did not have atrial thrombosis. Sodium nitrite in combination with quinacrine hydrochloride appeared to have no additional effect.

The toxic effects of intraperitoneal, intrauterine and intravenous administration of quinacrine hydrochloride solution were evaluated in female adult rhesus monkeys (Macaca mulatta). A single intraperitoneal injection of 400 mg and above resulted in the development of toxic manifestations leading to death of monkeys. Intrauterine instillation of 500 mg of quinacrine was well tolerated and did not produce any toxic effects. However, intravenous injection of 100 and 75 mg was lethal to the animals.

Acridine, the parent nucleus of atabrine, is much more toxic than its 4,5-dimethyl derivative. The 4,5-dimethyl derivative of atabrine was therefore synthesized in the hope of producing a better-tolerated drug. The analogue was considerably more toxic than atabrine.

Escherichia coli K12ND-160 possesses characteristics which make it highly suitable for studies on mutagenic/antimutagenic specificity and has been used to investigate such effects for several agents. Nitrofurazone (NFZ) was used as a mutagen at non-lethal concentrations; it causes mutation from fucose sensitivity to resistance (FucS----FucR) and from inability to utilize melibiose to melibiose utilization (Mel(-)----Mel+), but does not induce mutations from deoxygalactose sensitivity to resistance (DGAS----DGAR). Caffeine is mutagenic for reversions from lactose non-utilization to utilization (Lac(-)----Lac+) and mutations from FucS----FucR, but it is antimutagenic for mutations from 6-azauracil sensitivity to resistance (AzaUS----AzaUR) and Mel(-)----Mel+ reversions and produces no effect on spontaneous DGAS----DGAR mutations. Added guanosine and cytidine (G + C at 100 micrograms/ml each) exert antimutagenic activity against spontaneous Lac(-)----Lac+ reversion, but not against caffeine-induced Lac(-)----Lac+ reversions; a strong antimutagenic effect on spontaneous Mel(-)----Mel+ reversion is also observed. The addition of G + C does not result in either mutagenic or antimutagenic effects against spontaneous or NFZ-induced FucS----FucR or DGAS----DGAR mutations; it is, however, strongly mutagenic for AzaUS----AzaUR mutations. The 'natural antimutagen', chlorophyllin, is antimutagenic for DGAS----DGAR mutations, but fails to demonstrate such activity against spontaneous or caffeine-induced Lac(-)----Lac+ reversion, spontaneous or NFZ-induced Mel(-)----Mel+ reversion, or spontaneous or NFZ-induced FucS----FucR mutation.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolated hepatocytes provide a suitable system for investigation of various aspects of the mechanism of a toxic response. The mechanism by which most chemicals induce hepatotoxicity is still not known. Evidence that phospholipases may play a role in cellular injury has been reported. In the present study the effects of reported inhibitors of phospholipase A2 (quinacrine, chlorpromazine, dexamethasone, and dibutyryl cyclic AMP) on diethyl maleate (DEM)-induced lipid peroxidation, reduced glutathione (GSH) depletion, and cellular injury were examined in isolated hepatocyte suspensions. Hepatocytes were incubated for 7 h under control conditions or with (1) DEM (4 mM), (2) one of the inhibitors (quinacrine, 10, 50, or 150 microM; chlorpromazine, 50 microM; dexamethasone, 0.1, 0.5, 1, or 2.5 mM; dibutyryl cyclic AMP, 0.1, 0.5, 1, or 2.5 mM) or aspirin (500 microM), or (3) a combination of DEM and one of the inhibitors or aspirin to determine their effect on DEM toxicity. Samples were withdrawn at hourly intervals for estimation of cellular injury (loss of intracellular K+ and lactate dehydrogenase and trypan blue exclusion index), lipid peroxidation (thiobarbituric acid reactants assay), and GSH concentration. Quinacrine and chlorpromazine inhibited DEM-induced lipid peroxidation but not cellular injury or GSH loss. This suggests that phospholipase A2 may be involved in DEM-induced lipid peroxidation but not cell damage. However, dexamethasone and dibutyryl cyclic AMP enhanced both lipid peroxidation and loss of cell viability due to DEM, suggesting novel aspects of the biochemical mechanisms of chemically induced cytotoxicity.