Synthesis and antitumor activity of novel benzophenone derivatives

Novel benzophenone derivatives were synthesized and screened for cytotoxic and antitumor activity. Friedel-Crafts condensation was employed to construct the benzophenone skeleton. Among the compounds synthesized, morpholino and thiomorpholino benzophenones 3a-d exhibited potent cytotoxic activity against P388 murine leukemia and PC-6 human lung carcinoma cells in vitro, and compounds 3a, 3c, and 3j, when administered intraperitoneally, showed significant antitumor activity against the malignant ascites caused by intraperitoneal inoculation of P388 cells in mice.     

Thymoquinone ameliorates the nephrotoxicity induced by cisplatin in rodents and potentiates its antitumor activity

The effects of thymoquinone (TQ) on cisplatin-induced nephrotoxicity in mice and rats were studied. Oral administration of TQ (50 mg/L in drinking water) for 5 days before and 5 days after single injections of cisplatin (5 mg/kg, i.v., in rats and 7 or 14 mg/kg, i.p., in mice) greatly ameliorated cisplatin-induced nephrotoxicity in both species. In rats, i.v. cisplatin caused 4- and 5-fold elevations in serum urea and creatinine, a 235% increase in urine volume, a 41% increase in kidney weight, 8.5-fold decrease in creatinine clearance, and extensive histological damage 5 days after treatment. In mice, similar alterations in kidney function were observed. TQ-induced amelioration of cisplatin nephrotoxicity was evident by significant reductions in serum urea and creatinine and significant improvement in polyuria, kidney weight, and creatinine clearance. The protective effects of TQ against cisplatin-induced nephrotoxicity in the rat were further confirmed by histopathological examination. To evaluate the possible modification of the antitumor activity of cisplatin by TQ, we studied their interaction in Ehrlich ascites carcinoma (EAC) bearing mice. The results revealed that TQ potentiated the antitumor activity of cisplatin. The current study suggests that TQ may improve the therapeutic index of cisplatin.     

Naphthazarin derivatives: synthesis, cytotoxic mechanism and evaluation of antitumor activity

Patients with type Ib glycogen storage disease (GSD Ib) are susceptible to hypoglycaemic episodes. To determine whether an amylase (alpha-glucosidase) inhibitor, voglibose, can be useful in the control of hypoglycaemia, we tried it in a 14-y-old male with GSD Ib. Oral administration of voglibose prolonged the duration of normoglycaemia and reduced the incidence of hypoglycaemia attacks. These findings indicate that voglibose may be useful for preventing hypoglycaemia in GSD Ib patients.     

Synthesis and antitumor activity of duocarmycin derivatives: A-ring pyrrole compounds bearing cinnamoyl groups

A series of N-cinnamates of the A-ring pyrrole compound of duocarmycin were synthesized and evaluated for in vitro anticellular activity against HeLa S3 cells and in vivo antitumor activity against murine sarcoma 180 in mice. The 4'-methoxy- and 4'-BocNH-cinnamates exhibited strong in vitro anticellular activity among the synthesized compounds. The ortho substitution of the 4'-methoxycinnamate did not affect the anticellular activity and contributed to an enhancement of water solubility. Most of the 8-O-(N,N-dialkylcarbamoyl) derivatives of the 4'-methoxycinnamate displayed remarkably superior in vivo antitumor activity to duocarmycin A or B2. Moreover, it is noteworthy that these 8-O-(N,N-dialkylcarbamoyl) derivatives exhibited significant antitumor activity at wider range of doses as compared with the A-ring pyrrole derivatives having the trimethoxyindole skeleton in segment B.     

Substrate specificity for isomerase activity of macrophage migration inhibitory factor and its inhibition by indole derivatives

Macrophage migration inhibitory factor (MIF) was discovered as a cytokine that inhibits random migration of macrophages and concentrates them at inflammatory loci. We recently reported the tertiary structure of MIF, and revealed its similarity to that of 5-carboxymethyl-2-hydroxymuconate isomerase. Moreover, MIF was found to have isomerase activity converting D-dopachrome, a stereoisomer of naturally-occurring L-dopachrome, to 5,6-dihydroxyindole-2-carboxylic acid. In this study, we examined the effects of a series of compounds analogous to D-dopachrome on the enzyme activity to obtain vital information for identification of a natural substrate of MIF. Adrenochrome, lacking a carboxyl group at position 2 of the indolinequinone ring, could not be a substrate. Several indole-ring-containing compounds with a carboxyl group were inhibitory to D-dopachrome isomerase activity, of which indole-3-acrylic acid was the most potent inhibitor, with an inhibitor constant (Ki) of 2.8 mM. 2,3-Indolinedione, which lacks a complete indole ring or a carboxyl group but has carbonyl groups at positions 2 and 3, apparently inhibited the enzyme activity in a competitive or mixed manner with a Ki of 0.9 mM. Taken together, these facts suggest that the 2-carboxyl group of the substrate is essential for interaction with the active site of MIF.     

Anti-mutagenic activity of DNA damage-binding proteins mediated by direct inhibition of translesion replication

DNA lesions that block replication can be bypassed in Escherichia coli by a special DNA synthesis process termed translesion replication. This process is mutagenic due to the miscoding nature of the DNA lesions. We report that the repair enzyme formamido-pyrimidine DNA glycosylase and the general DNA damage recognition protein UvrA each inhibit specifically translesion replication through an abasic site analog by purified DNA polymerases I and II, and DNA polymerase III (alpha subunit) from E. coli. In vivo experiments suggest that a similar inhibitory mechanism prevents at least 70% of the mutations caused by ultraviolet light DNA lesions in E. coli. These results suggest that DNA damage-binding proteins regulate mutagenesis by a novel mechanism that involves direct inhibition of translesion replication. This mechanism provides anti-mutagenic defense against DNA lesions that have escaped DNA repair.     

Biochemical modulation of tumor cell energy in vivo: II. A lower dose of adriamycin is required and a greater antitumor activity is induced when cellular energy is depressed

A quadruple drug combination--consisting of a triple-drug combination of N-(phosphonacetyl)-L-aspartate (PALA) + 6-methylmercaptopurine riboside (MMPR) + 6-amino-nicotinamide (6-AN), designed to primarily deplete cellular energy in tumor cells, + Adriamycin (Adria)--yielded significantly enhanced anticancer activity (i.e., tumor regressions) over that produced by either Adria alone at maximum tolerated dose (MTD) or by the triple-drug combination, against large, spontaneous, autochthonous murine breast tumors. The adenosine triphosphate (ATP)-depleting triple-drug combination administered prior to Adria resulted in a 100% tumor regression rate (12% complete regression; 88% partial regression) of spontaneous tumors. Histological examination of treated tumors demonstrated that the treatment-induced mechanism of cancer cell death was by apoptosis. The augmented therapeutic results (100% tumor regressions) were obtained with approximately one-half the MTD of Adria as a single agent and suggest the potential clinical benefit of longer, more effective, and safer treatment by low doses of Adria when combined with the triple-drug combination. Two likely mechanisms of action are discussed: (1) prevention of DNA repair; (2) complementary disruption of biochemical pathways by both the triple-drug combination and the biochemical cascade of apoptosis that is induced by a DNA-damaging anticancer agents such as Adria.     

The effect of cyclophosphamide on the experimental inflammation induced by the toxic mushroom Cortinarius speciosissimus in the rat kidney

A single intraperitoneal dose of cyclophosphamide (150 mg/kg) given at the same time as an oral dose of Cortinarius speciosissimus prevented the renal inflammation induced by this toxic mushroom in the male rat. Furthermore, a scar formation around dilated collecting ducts was clearly reduced by cyclophosphamide treatment. In general the only lesions observed in the cyclophosphamide treated animals were dilated collecting ducts in the outer medullary zone, the epithelia of which were either in regenerative mitosis or were atrophic. Apparently the primary sites of action of Cortinarius toxins in male rats are the collecting ducts of the outer medullary zone. When inflammation and the subsequent scar formation is prevented by cyclophosphamide, the damaged tubules can regenerate by mitotic activity and perhaps restore normal function.     

Enhanced binding to DNA and topoisomerase I inhibition by an analog of the antitumor antibiotic rebeccamycin containing an amino sugar residue

Many antitumor agents contain a carbohydrate side chain appended to a DNA-intercalating chromophore. This is the case with anthracyclines such as daunomycin and also with indolocarbazoles including the antibiotic rebeccamycin and its tumor active analog, NB506. In each case, the glycoside residue plays a significant role in the interaction of the drug with the DNA double helix. In this study we show that the DNA-binding affinity and sequence selectivity of a rebeccamycin derivative can be enhanced by replacing the glucose residue with a 2'-aminoglucose moiety. The drug-DNA interactions were studied by thermal denaturation, fluorescence, and footprinting experiments. The thermodynamic parameters indicate that the newly introduced amino group on the glycoside residue significantly enhanced binding to DNA by increasing the contribution of the polyelectrolyte effect to the binding free energy, but does not appear to participate in any specific molecular contacts. The energetic contribution of the amino group of the rebeccamycin analog was found to be weaker than that of the sugar amino group of daunomycin, possibly because the indolocarbazole derivative is only partially charged at neutral pH. Topoisomerase I-mediated DNA cleavage studies reveal that the OH-->NH2 substitution does not affect the capacity of the drug to stabilize enzyme-DNA covalent complexes. Cytotoxicity studies with P388 leukemia cells sensitive or resistant to camptothecin suggest that topoisomerase I represents a privileged intracellular target for the studied compounds. The role of the sugar amino group is discussed. The study provides useful guidelines for the development of a new generation of indolocarbazole-based antitumor agents.     

Synthesis and antitumor activity of leinamycin derivatives: modifications of C-8 hydroxy and C-9 keto groups

A series of leinamycin derivatives were synthesized and evaluated for antitumor activity. Modifications at C-8 and C-9 positions revealed a broad structure-activity relationship in vitro and some derivatives showed potent antiproliferative activity against HeLa S3 cells.     

Experimental study on antagonizing action of herba Epimedii on side effects induced by glucocorticoids

The experimental result has shown that the water extract of Herba Epimedii (Epimedium sagittalum) works very well in preventing and curing the side effects induced by long-term use of glucocorticoids in rats, especially in antagonizing adrenocortical atrophy and osteoporosis.     

Effects of hypoxia on the use-dependent inhibition of conduction velocity induced by cibenzoline in guinea pig ventricular myocardium

The objective of this study was to determine the combined accuracy of emergency department (ED) cardiac enzymes and electrocardiograms (ECGs) in patients who were admitted to "rule-out" myocardial infarction (ROMI). A retrospective analysis of ED creatinine kinase (CK), CKMB, and ECG was performed and the results were compared with final hospital diagnosis of MI, in the ED of a medical school- and university hospital-affiliated teaching Veterans Affairs Medical Center. Approximately 222 consecutive ED patients admitted to ROMI, including 43 (19%) MI patients, 29 (67%) of whom presented to the ED within 24 hours of symptom onset were eligible to participate. Interventions included an analysis of CK and CKMB results and ECG findings. There were no statistical differences in the sensitivities, specificities, and predictive values when the two cardiac enzymes were compared. Almost all of the elevated cardiac enzyme results occurred in MI patients who presented within 24 hours of symptom onset, more than half of whom had ED cardiac enzyme elevations. For all MI patients, regardless of duration of symptoms, more than half of the ED ECGs had new ST-T changes consistent with an acute MI or acute myocardial ischemia. In the MI patients who presented within 24 hours of symptom onset, 79% had positive enzymes or ECG or both in the ED. No statistically significant difference in the sensitivity rates for MI between the CK and CKMB comparing enzymes with ECGs was found.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anticonvulsant activity and inhibition of cellular respiratory activity by substituted imidazolocarbamides

Several 1-(1-aryl-2-mercaptoacetylimidazole)-3-alkylcarbamides were synthesized and characterized by their sharp melting points, elemental analyses, and IR spectra. These substituted imidazolocarbamides possessed anticonvulsant activity, which was reflected by the 20-80% protection observed with these compounds against pentylenetetrazol-induced convulsions in mice. These substituted imidazolocarbamides selectively inhibited the in vitro oxidation of nicotinamide adenine dinucleotide (NAD)-dependent oxidations of pyruvate, alpha-ketoglutarate, beta-hydroxybutyrate, and NADH by rat brain homogenates. However, NAD-independent oxidation of succinate was not affected. The anticonvulsant activity possessed by 1-(1-aryl-2-mercaptoacetylimidazole)-3-alkylcarbamides had no relationship to their ability to inhibit cellular respiratory activity.     

Inhibition of angiogenesis by antitumor antibiotic C1027 and its effect on tumor metastasis

Seven genes were regionally localized on rat Chromosome (Chr) 1, from 1p11 to 1q42, and two of these genes were also included in a linkage map. This mapping work integrates the genetic linkage map and the cytogenetic map, and allows us to orient the linkage map with respect to the centromere, and to deduce the approximate position of the centromere in the linkage map. These mapping data also indicate that the Slc9a3 gene, encoding the Na+/H+ exchanger 3, is an unlikely candidate for the blood pressure loci assigned to rat Chr 1. These new localizations expand comparative mapping between rat Chr 1 and mouse or human chromosomes.     

Synthesis, cytotoxicity and antitumor activity of some new simplified pyrazole analogs of the antitumor agent CC-1065. Effect of an hydrophobic group on antitumor activity

Three simplified pyrazole analogs (7-9) of the antitumor agents CC-1065, were synthesized. In in vitro assays, against L1210 cell lines all derivatives showed a cytotoxicity in a pM range, values close to the natural target compound (+)-CC-1065. In in vivo tests, against disseminate L1210 leukemia cells, synthesized compounds showed a good potency (O.D. 300 micrograms/Kg) but no activity. These observations further validate the effect of the hydrophilic and/or hydrophobic characteristics of the substituents present on the molecules, confirming the relevance of this phenomena on in vivo activity. In fact in this case the increase of hydrophobic characteristics of the molecules produce the loss of activity, probably due to a worse bioavailability of the drugs in animals.     

Effects of Ca2+ channel blockers on Ca2+ loading induced by metabolic inhibition and hyperkalemia in cardiomyocytes

The treatment of neuropathic pain with opioid analgesics is a matter of controversy among clinicians and clinician scientists. Although neuropathic pain is usually believed to be only slightly responsive to opioids, several studies show that satisfactory analgesia can be obtained if adequate doses are administered. In the present study, we tested the effectiveness of buprenorphine in 21 patients soon after thoracic surgery (nociceptive postoperative pain) and 1 month after surgery in the same 21 patients who developed postthoracotomy neuropathic pain with a burning, electrical and shooting quality. According to a double-blind randomized study, the analgesic dose (AD) of buprenorphine needed to reduce the long-term neuropathic pain by 50% (AD50) was calculated and compared to the AD50 in the immediate postoperative period. We found that long-term neuropathic pain could be adequately reduced by buprenorphine. However, the AD50 in neuropathic pain was significantly higher relative to the AD50 in the short-term postoperative pain, indicating a lower responsiveness of neuropathic pain to opioids. We also found a strict relationship between the short-term and long-term AD50, characterized by a saturating effect. In fact, if the AD50 soon after surgery was low, the AD50 increase in the long-term neuropathic pain was threefold. By contrast, if the AD50 soon after surgery was high, the AD50 in neuropathic pain was only slightly increased. This suggests that, though neuropathic pain is indeed less sensitive to opioids, in some neuropathic patients a large amount of opioid resistance is already present in other painful conditions.     

Association of macrophage activation with antitumor activity by synthetic and biological agents

Treatment of normal BALB/c mice i.p. with a number of adjuvants, including pyran copolymer, the copolymer of polyinosinic and polycytidylic acids, Bacillus Calmette-Guérin, glucan, and dextran sulfate, rendered macrophages nonspecifically cytostatic for syngeneic tumor cells. Macrophage activation was highly dose dependent. The validity of the inhibition of DNA synthesis assay for measuring macrophage-induced cytostasis of target cells was proven by demonstrating a concurrent decrease in RNA synthesis and a reduction in viable tumor cell number. Moreover, conditioned supernatants from pyran-activated macrophages did not significantly decrease [3H]thymidine incorporation by freshly added leukemia cells. Biological or synthetic agents that activated macrophages were generally effective systemic antitumor agents against the M109 lung carcinoma. Drugs that did not activate macrophages, such as typhoid vaccine, tilorone, levamisole, WY-13876, and thymosin, were ineffective in prolonging the life of tumor-bearing mice. Pyran treatment i.p. was the most effective antitumor adjuvant in two separate tumor models, and suppression of tumor growth appeared to be related not only to an increase in macrophage tumoricidal function, but also to a larger influx of macrophages responding at the tumor site.     

Immunomodulating and hepatoprotective action of retinoids in toxic liver involvement induced by D-galactosamine

The experiments on Wistar rats showed that beta-carotene and retinol acetate decreased the level of the biochemical signs of the hepatocyte injury and lowered or abolished the immunosuppressive effect induced by D-galactosamine. The hepatoprotective and immunomodulating effects of beta-carotene were higher. D-Galactosamine induced the development of the immunosuppressing properties in light erythrocytes and retinol acetate induced the development of the immunostimulating properties in heavy erythrocyte of the poisoned animals. beta-carotene prevented the development of the immunosuppressing properties in such cells. The immunomodulating effect of beta-carotene in the toxic affection of the liver was associated with blocking or retarding of the entry of the suppressing substances to the vascular channel from the hepatocytes and did not depend on their action on the erythrocytes.