Mononuclear copper(II) complexes with 2-thiophene carboxylate and N-N donors; DNA interaction, antioxidant/anti-inflammatory and antitumor activity.

Redox-active compounds such as copper-phenanthroline are known as artificial/chemical nucleases with a great impact and potential for their applications as metallotherapeutics. In that vein, the mononuclear copper(II) complexes [Cu(L)2(bipy)] (1), [Cu(L)2(bipy)(H2O)] (2) and [Cu(L)2(phen)(H2O)] (3), where L = 2-thiophene carboxylate, bipy = 2,2΄-bipyridine and phen = 1,10-phenanthroline, have been prepared and pharmacochemically studied, while the crystal structure of 1 is also reported. All the tested complexes preferably bind to CT-DNA via minor groove as resulted from UV spectroscopy studies, luminescent titration, EB competition assays and viscosity measurements. Complexes 2 and 3 in aqua behave like a "light switch" for DNA. The intensity enhancement, with the increase of DNA concentration, reached about 3-fold for 2 and 10-fold for 3. In vitro antioxidant activity of compounds 1-3, was evaluated using two different antioxidant assays: a) interaction with 1,1-diphenyl-2-picryl-hydrazyl (DPPH) stable free radical and b) inhibition of lipid peroxidation. Moreover, their inhibitory activity on soybean lipoxygenase (LOX) was evaluated for their anti-inflammatory potency. The tested complexes showed good activity on both lipid peroxidation and soybean LOX inhibition while complex 2 exhibited the best antioxidant/anti-inflammatory activity. A computational analysis over the LOX protein structure 1JNQ was performed, in an effort to support their possible mode of action. The cytotoxicity of the complexes was determined and their efficacy against several human cancer cell lines (ovarian, OAW-42; lung, A549; colon, HT29; breast, MDA-MB-231; kidney, Caki-2; and cervical, Hela) and human non-tumor cell lines (lung, MRC-5; and breast, MTSV1-7) were evaluated. The best cytotoxic activity was appeared for complex 3. In silico, computational methods support antiestrogen activity of the administered complexes on normal breast cells.

Preclinical evaluation of amiodarone for the treatment of murine leukemia P388. In vivo and in vitro investigation.

PURPOSE: The purpose of the present study was the investigation of antileukemic effect of amiodarone in leukemia P388 BDF1 bearing mice and its genotoxic and cytostatic effect in cultured normal human lymphocytes. METHODS: Leukemia P388 was used in this study. BDF1 mice were used for chemotherapy evaluation in vivo. The antitumor activity was assessed by the oncostatic parameter T/C, representing the increase of life span of drug-treated animals vs. controls. Lymphocyte cultures were used to study the genotoxic and cytostatic effect in vitro, expressed by enhanced sister chromatid exchange (SCE) and reduced proliferation rate indices (PRIS). RESULTS: Amiodarone was found to exert antileukemic potency against leukemia P388 bearing mice at all three different treatment schedules used, yielding T/C values of 155%, 163% with one cure and 230%. In the in vitro cytogenic experiments, significant increase of SCE rates by amiodarone was observed at 0.2 µM, while at the same concentration significant suppression of PRIS was achieved. CONCLUSION: According to the National Cancer Institute (NCI), a compound is characterized as potential chemotherapeutic deserving further evaluation if it produces T/C values≥125%. On the other hand the SCE assay has predictive value as a clinical assay for drugs exhibiting a strong correlation between cell killing and induction of SCEs. Further studies are warranted to clarify the structure-activity relationship of amiodarone.

Effect of navelbine on inhibition of tumor growth, cellular differentiation and estrogen receptor status on Lewis lung carcinoma.

We studied the antitumor activity of Navelbine (NVB) together with its ability to induce cellular differentiation and to influence estrogen receptor status of Lewis lung carcinoma (LLC). A total of 32 C(57)B1 mice divided into 5 groups were used for transplantation of LLC. Four groups of mice were treated with 5.0, 2.5 and 1.25 mg/kg/day from day 1 to 9 and 1.25 mg/kg on days 1, 7 and 13. Eight mice were controls. The dose of 1.25 mg/kg/day was the most effective and produced 72.7% inhibition of tumor growth. Ultrastructurally, on day 1 the cells showed poor differentiation. On day 14, in the case of 72.7% inhibition of tumor growth the study revealed a significant restoration of the morphology of the cells. Estrogen receptors gave a positive value in contrast to the initial measurement which was negative. The present study demonstrated good antitumor activity of NVB on LLC. NVB may also induce cellular differentiation and influence the estrogen receptor status.

Albumin possesses intrinsic enolase activity towards dihydrotestosterone which can differentiate benign from malignant breast tumors.

Serum albumin was found to possess enolase activity towards the dihydrotestesterone (DHT) molecule, converting it from its 3-keto to 3-enol form. This activity was accompanied by albumin during all stages of purification, as well as following various treatments, a fact indicating that the enzymatic activity was an intrinsic property of albumin molecule and did not represent an impurity of the preparation. Enolase activity was decreased in parallel with the quantity of intact albumin molecules when proteolytic enzymes were used for their degradation. The activity was strongly inhibited by Ni (II) and Cu (II) ions, which bind to 3-histidine of the albumin molecule, as well as by oleic acid and cholesterol. It was also inhibited, in a reversible manner by surface-active agents. Enolase activity was found in all mammalian species studied, the specific activity however was very low in the serum of dogs. The administration of DHT to mice did not influence the albumin or enolase levels in their serum. The optimum pH of enolase was at 9.2, with a carbonate buffer solution. In addition to the serum enolase activity was found to be a feature of intracellular albumin. The two albumins exhibited the same specific activity and the same Km for DHT. The study of cytosolic albumin, obtained from human mammary gland tissue, revealed that benign and malignant tumors of this gland differed substantially with respect to their percentage of albumin. Significant differences were also observed in enolase activity, a consequence of the existence of a fraction of albumin in the malignant tissue in a polymeric form. This form exhibited a decreased enzymatic activity, compared to its monomeric form, exclusively encountered in benign breast specimens. The last observation, along with the quantitative differences of albumin in the two tissues, offers a possibility of reliable differentiation between benign and malignant breast tumors.

Enzymatic conversion of dihydrotestosterone from 3-keto to 3-enol form in the rat prostate.

Dihydrotestosterone (DHT) is the active androgen, as well as a strong tumor promoter in the prostate, where several enzymes are essential for the regulation of its activity. We localized four enzymes promoting the enolization of the 3-keto group of DHT in rat prostate. The enzymes were purified by ion-exchange chromatography, acetone fractionation and gel filtration to homogeneity, and found to have molecular sizes of 19.5, 22.0, 44.5 and 21.5 kDa. A partial characterization of the four enzymes revealed that their structure consisted of a common chain of 14.5 kDa with various subunits which differentiate the four enzymes from each other. All the enzymes exerted their activity only on 5-dihydro 3-keto steroids. The total enzymatic activity was strongly influenced by animal age, being very low before sexual maturation, as well as after castration. In the latter case the level of total activity fell to about 8% control animals. Activity was also estimated in human, pork, ram and bovine prostate and it was found that all these species have 20-25 times lower enzyme levels than rat. These results, in combination with the practically exclusive localization of the enzymes in the prostate, suggest a role relating to the bioavailability of DHT in this gland.