In vitro and in silico evaluation of the inhibitory effect of a curcumin-based oxovanadium (IV) complex on alkaline phosphatase activity and bacterial biofilm formation.

The scientific interest in the development of novel metal-based compounds as inhibitors of bacterial biofilm-related infections and alkaline phosphatase (ALP) deregulating effects is continuous and rising. In the current study, a novel crystallographically defined heteroleptic V(IV)-curcumin-bipyridine (V-Cur) complex with proven bio-activity was studied as a potential inhibitor of ALP activity and bacterial biofilm. The inhibitory effect of V-Cur was evaluated on bovine ALP, with two different substrates: para-nitrophenyl phosphate (pNPP) and adenosine triphosphate (ATP). The obtained results suggested that V-Cur inhibited the ALP activity in a dose-dependent manner (IC50 = 26.91 ± 1.61 µM for ATP, IC50 = 2.42 ± 0.12 µM for pNPP) exhibiting a mixed/competitive type of inhibition with both substrates tested. The evaluation of the potential V-Cur inhibitory effect on bacterial biofilm formation was performed on Gram (+) bacteria Staphylococcus aureus (S. aureus) and Gram (-) Escherichia coli (E. coli) cultures, and it positively correlated with inhibition of bacterial ALP activity. In silico study proved the binding of V-Cur at eukaryotic and bacterial ALP, and its interaction with crucial amino acids of the active sites, verifying complex's inhibitory potential. The findings suggested a specific anti-biofilm activity of V-Cur, offering a further dimension in the importance of metal complexes, with naturally derived products as biological ligands, as therapeutic agents against bacterial infections and ALP-associated diseases. KEY POINTS: • V-Cur inhibits bovine and bacterial alkaline phosphatases and bacterial biofilm formation. • Alkaline phosphatase activity correlates with biofilm formation. • In silico studies prove binding of the complex on alkaline phosphatase.

Administration of the extra virgin olive oil (EVOO) in mild cognitive impairment (MCI) patients as a therapy for preventing the progress to AD.

OBJECTIVE: Although Mediterranean diet is connected with longevity and lower rate of many disorders including Alzheimer's disease (AD), the effect of olive oil, which is the principal component of the Mediterranean diet, on fibrinolytic system related to AD and especially on plasminogen activator inhibitor-1 (PAI-1) and a2-antiplasmin in aged participants are not yet examined. This study was performed on 108 aged participants allocated into 5 groups: Mild Cognitive Impairment (MCI) (36) patients subjected to 1-year therapy with extra virgin olive oil (EVOO), MCI without therapy patients (26), MCI without therapy 1-year later patients (11), AD patients (30) and healthy individuals (16). Hypothesis/Purpose: To examine the effect of EVOO therapy on the fibrinolytic factors PAI-1 and a2-antiplasmin, on hallmarks of AD, tau and Aß amyloid fragments and on an oxidative stress biomarker, MDA in the serum of MCI patients aiming to be exploited as a future preventive therapy. RESULTS: Using ELISA method, the levels of both fibrinolytic factors PAI-1 and a2- antiplasmin in the serum of MCI patients were reduced notably in the EVOO treated patients versus the control group and were lower than those of all other groups. For better determination of AD from other pathological conditions the ratio Aß1-42/Aß1-40 was measured in serum of all participants. The more lessened the ratio is, the more cognitive impairment is observed in patients. The MCI group with one-year EVOO therapy displayed a ratio similar to this of healthy individuals. Moreover, patients with EVOO therapy showed decreased tau protein levels in comparison with all the other groups. The levels of the oxidative stress's biomarker, malondialdehyde (MDA) showed a significant decrease in MCI patients subjected to EVOO therapy revealing the involvement of the beneficial antioxidative properties of EVOO in the progression of AD. CONCLUSION: We demonstrated that EVOO therapy may prevent the risk of patients with MCI to progress to AD via decreasing fibrinolytic factors PAI-1 and a2 antiplasmin that reflecting in the diminution of the hallmarks proteins of AD, tau and Aß amyloid as well and in a biomarker of oxidative stress, MDA.

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.

Synthesis, structure elucidation and biological evaluation of triple bridged dinuclear copper(II) complexes as anticancer and antioxidant/anti-inflammatory agents.

Seeking for copper based metallo-therapeutics, three triple bridged dinuclear copper(II) complexes [Cu2(µ2-L2)(bipy)2(µ2-OH)(µ2-H2O)](NO3)2·H2O (1·H2O), [Cu2(µ2-L2)(bipy)2(µ2-OH)(µ2-NO3)](NO3)·0.6MeOH·0.4H2O (2·0.6MeOH·0.4H2O) and [Cu2(µ2-L1)(bipy)2(µ2-OH)(µ2-NO3)(H2O)](NO3)·2H2O (3·2H2O) where L2=2-thiophene acetato, L1=2-thiophene carboxylato and bipy=2,2'-bipyridine were synthesized and structurally characterized. The complexes were subjected in vitro to a pharmacochemical evaluation for their antioxidant/anti-inflammatory activity, cytotoxicity and efficacy against human ovarian, lung, colon, breast, kidney and cervical cancer cell lines along with non tumor human lung and breast cell lines. The biological results support the structure related cytotoxic activity of the compounds. Complex 3 presented a combination of best anticancer and anti-inflammatory activities. A computational analysis over the LOX-3 protein structure 1JNQ was performed to support the possible mode of action.

A novel silver iodide metalo-drug: experimental and computational modelling assessment of its interaction with intracellular DNA, lipoxygenase and glutathione.

The new mixed ligand silver(I) complex of formula [AgI(TPP)2(MBZT)] (1) was obtained by reacting 2-mercapto-benzothiazole (MBZT) with triphenylphosphine (TPP). The complex was characterized by m.p., vibrational spectroscopy (FT-IR), (1)H NMR, UV-vis, ESI-MS spectroscopic techniques and its structure was confirmed by X-ray crystallography. Mixed ligand complexes of silver(I) iodide with thiones and phosphines are very rare in the literature and to the best of our knowledge compound 1 is the first of this kind exhibiting significant biological effects. Complex 1 was evaluated for its in vitro cytotoxic activity (cell viability) under irradiation with UV light and without irradiation against human cancer cell lines: MCF-7 (breast, ER positive), MDA-MB-231 (breast, ER negative), Caki-1 (renal), A549 (lung), OAW-42 (ovarian), HeLa (cervical) and additionally against the normal human lung cell line MRC-5 (normal human fetal lung fibroblast cells) and normal immortalized human mammary gland epithelial cell line (MTSV17) with SRB assay. The results showed that 1 mediates a strong cytotoxic response to the tested normal and cancer cell lines. It exhibits equal activity against MDA-MB-231 cells where estrogen receptors (ERs) are devoid with the one against MCF-7 where ERs are present. Molecular docking studies have shown that 1 is docked in the different pocket than that of the ERs modulators. The binding affinity of 1 towards the intracellular molecules DNA and lipoxygenase (LOX) was studied for the evaluation of the mechanism of its cytostasis. The binding constant (Kb) of 1 towards CT-DNA was calculated by UV-Vis and fluorescent spectra suggesting intercalation or electrostatic interactions of 1 into DNA. Docking studies on DNA-complex interactions confirm the binding of 1. Moreover, the influence of complex 1 on the catalytic peroxidation of linoleic acid to hydroperoxylinoleic acid by the enzyme lipoxygenase (LOX) was kinetically and theoretically studied. In addition, since the deactivation of cisplatin caused by glutathione, seems to be an important determinant of its cytotoxic effects, the reaction of 1 with glutathione (GSH) was investigated by UV-absorption spectroscopy.

Dexamethasone plus octreotide regimen increases anticancer effects of docetaxel on TRAMP-C1 prostate cancer model.

AIM: The aim of this study was to evaluate whether the neoadjuvant use of the dexamethasone (DEX) plus octreotide (OCT) regimen can improve the direct anticancer effects of docetaxel (DOC) in the TRAMP-C1 prostate cancer model. MATERIALS AND METHODS: TRAMP-C1 cells were first characterized for the expression of SSTR1-5 and then were inoculated onto the femur of C57Bl mice. Investigation protocols employed TRAMP-C1 cell proliferation and invasion assays, analysis of radiographic images of the bone lesions and overall survival of the diseased animals. RESULTS: The triple combination treatment scheme showed significant anticancer effects, in both proliferation and invasion assays, compared to any single agent treatment scheme. DOC treatment following the neoadjuvant administration of DEX plus OCT regimen improved significantly the anticancer effects both on the grading of the bone lesions and on the overall survival of the diseased animals. CONCLUSION: Our data suggest that the neoadjuvant administration of DEX plus OCT regimen can improve the anticancer effects of DOC on the TRAMP-C1 model.

Synthesis, structural characterization and biological studies of the triphenyltin(IV) complex with 2-thiobarbituric acid.

The reaction between 2-thiobarbituric acid (H(2)TBA), which was treated with an equimolar amount of potassium hydroxide, in a water with triphenytin chloride in methanol, results in the formation of the {[Ph(3)Sn(O-HTBA)]}(n) (1) complex. Crystals of the hydrated 1 with formula {[Ph(3)Sn(O-HTBA)]·0.7(H(2)O)}(n) were growth from methanol/acetonitrile solution, of the white precipitation, filtered off, from the reaction. The crystal structure of complex 1 has been determined by X-ray diffraction at 120 K. Complex 1 is polymeric. The geometry around the tin(IV) ions is trigonal bi-pyramidal with coordination to three C atoms from phenyl groups and one O atom from a de-protonated HTBA ligand. Complex 1 and the already known [(n-Bu)(3)Sn(O-HTBA)·H(2)O] (2) were evaluated for their in vitro cytotoxic activity (cell viability) against human cancer cell lines: HeLa (cervical), OAW-42 (ovarian), MCF-7 (breast, ER positive), MDA-MB-231 (breast, ER negative), A549 (lung), Caki-1 (renal) and additionally, the normal human lung cell line MRC-5 (normal human fetal lung fibroblast cells) and normal immortalized human mammary gland epithelial cell line MTSV17 with a Trypan Blue assay. Moreover complex 1 was evaluated for its in vitro cell growth proliferation activity against leiomyosarcoma cells (LMS), MCF-7 and MRC-5 cells with a Thiazolyl Blue Tetrazolium Bromide (MTT) assay. The type of cell death caused by complexes 1 and 2 was also evaluated by use of flow cytometry assay. The results showed that these compounds mediate a strong cytotoxic response to normal and cancer cell lines tested through apoptosis and induce cell cycle arrest in S phase of the cell cycle, suggesting DNA intercalation (direct or indirect) with the complexes. Finally, the influence of these complexes 1 and 2 upon the catalytic peroxidation of linoleic acid to hydroperoxylinoleic acid by the enzyme lipoxygenase (LOX) was kinetically and theoretically studied.

Preparation and pharmacochemical evaluation of mixed ligand copper(II) complexes with triethanolamine and thiophenyl-2 saturated carboxylic acids.

The dinuclear complex [Cu(2)(L(1))(2)(H(2)tea)(2)] (1) as well as the linear trinuclear complexes [Cu(3)(L(1))(4)(H(2)tea)(2)] (2), [Cu(3)(L(2))(4)(H(2)tea)(2)] (3) and [Cu(3)(L(1))(2)(H(2)tea)(2)(NO(3))(2)] (4) where L(1) = 2-thiophene carboxylato, L(2) = 2-thiophene acetato and H(2)tea = the single deprotonated form of triethanolamine have been prepared and pharmacochemically studied. The crystal structure of 1 is also reported. In vitro antioxidant activity of free ligands and their respective copper complexes includes: a) interaction with 1,1-diphenyl-2-picrylhydrazyl stable free radical, b) the ΗΟ˙ mediated oxidation of DMSO, c) scavenging of superoxide anion radicals, d) inhibition of lipid peroxidation and e) soybean lipoxygenase inhibition. The results indicate selectivity of the complexes to different free radicals as a consequence of their physichochemical features. The majority of the complexes 1, 2, 3, 4 effectively inhibit lipid peroxidation. The trinuclear complex 3 is by far the most active with IC(50)=10 µM, within the set, followed by complexes 1 and 2. The complexes were evaluated for their efficacy as anticancer agents against different cancer and normal human cell lines. Results showed that, these compounds mediate a moderate cytotoxic response to normal and cancer cell lines tested and induce cell cycle arrest in G2/M phase of the cell cycle. Flow cytometric analysis suggested that the tested compounds can induce apoptosis.

Positive urinary cytology in patients with lung cancer in the absence of obvious urine tract metastases.

PURPOSE: To study the phenomenon of positive urine cytology in patients with lung cancer in the absence of obvious urothelial metastases. PATIENTS AND METHODS: 150 patients with small (SCLC) and non-small cell lung cancer (NSCLC) of all stages and 3 control groups were prospectively studied. Immunocytochemical study (cytokeratins 7-20, TTF1) in all positive urine specimens and chemokine profile (CXCR4, CCL21) study of the primary tumor in selected positive patients was performed. In experimental study, C57Bl/6 BALB/C mice injected with LLC lung and 4T1 mammary cancer cells were used for the detection of positive urine cytology. RESULTS: 11% of patients with NSCLC, 7% of patients with SCLC and none of the control group had positive urine cytology. In NSCLC, metastatic disease and high tumor burden positively correlated (p=0.01 and 0.03 respectively) with the phenomenon. In SCLC, correlation with extensive disease and multiple metastatic sites (p=0.02 and 0.04 respectively) was found. No correlation was found in either group with: age, gender, histology, performance status, line of chemotherapy, previous platinum-based chemotherapy, adrenal metastases, renal function, abnormal urinary sediment, response to chemotherapy and overall survival (p=0.9). Distinctive chemokine expression was identified in positive patients studied and was not observed in negative patients (×2 p=0.008). In the experimental study, only the LLC lung cancer cells were detected in the urine cytology of mice. CONCLUSION: This phenomenon, carrying undefined pathophysiological mechanisms, seems to characterize only patients with metastatic/extensive disease and high tumor burden. Further studies are needed to validate our preliminary chemokine expression results.

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.

Inhibition of rat hepatic CYP2E1 by quinacrine: molecular modeling investigation and effects on 4-(methyl nitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced mutagenicity.

Increased activity of CYP2E1 has been associated with increased risk of chemically-mediated cancers, through enhanced activation of a variety of procarcinogens. In this context, inhibition of CYP2E1 is potentially of significance in xenobiotic toxicity. The aim of the present study was to test the hypothesis that quinacrine inhibits hepatic CYP2E1. For this purpose, disulfiram (75 mg/kg i.p) as an inhibitor and isoniazid (100 mg/kg i.p) as an inducer of CYP2E1, as well as quinacrine (50 mg/kg i.p) were administered to Wistar rats and the hepatic activity of CYP2E1 was measured. The expression of CYP2E1 was further assessed by Western blot analysis. As expected, disulfiram inhibited, while isoniazid induced the activity and expression of the enzyme. Interestingly, treatment with quinacrine resulted in a significant decrease of CYP2E1 activity and expression. To investigate any similarities in the inhibition of CYP2E1 by quinacrine and disulfiram, molecular modeling techniques were adopted and revealed that quinacrine molecule anchors inside the same binding pocket of the protein where disulfiram is also attached. Finally, as assessed by the sister chromatid exchanges (SCE) assay, quinacrine was demonstrated to reduce the mutagenic effects of the tobacco-specific N-nitrosamine 4-(methyl nitrosamino)-1-(3-pyridyl)-1-butanone (NNK), which is known to be converted to active mutagen in the liver principally through CYP2E1. We suggest that these antimutagenic effects of quinacrine could be possibly attributed, at least in part, to its ability to block the bioactivation of NNK, mainly by the inhibition of CYP2E1. Our results, even preliminary, indicate that quinacrine as an inhibitor of CYP2E1 might be protective against chemically-induced toxicities such as NNK-induced mutagenicity.

Preclinical studies of steroid-linked nitrosoureas in murine pancreatic adenocarcinoma PANO2.

PURPOSE: In earlier studies, this laboratory carried out research on the synthesis and anticancer evaluation of hybrid compounds, which combine two molecules in one such as homo-aza-steroidal esters (HASE) of carboxylic derivatives of N, N-bis (2-chloroethyl) aniline. In this combination, steroidal hormones are employed as carriers for transporting the alkylating agents to specific targeted tissues. Aiming to continue our research, we used alkylating agents, as nitrosoureas, instead of nitrogen mustards. In this work the N-[N- (2-chloroethyl)-N-nitroso-carbomoyl]-L-alanine (CNC-ala) has been used and was bound to 7 newly synthesized modified steroidal esters (carrier molecule) of nitrosourea and the hybrid molecules were tested for antitumor activity against PANO2 murine pancreatic adenocarcinoma. MATERIALS AND METHODS: PANO2 adenocarcinoma was used in this study. C57Bl mice were used for chemotherapy evaluation. The activity was assessed from the inhibition of tumor growth and the oncostatic parameter T/C %. RESULTS: The antitumor activity displayed by 7 hybrid steroidal esters of nitrosourea was quite interesting. It was able to discern 4 of 7 compounds that exhibited considerable antitumor activity, increasing the lifespan of the tumor-bearing mice by inhibiting the tumor growth. CONCLUSION: The comparative study of 7 newly synthesized hybrid steroidal esters of nitrosourea shows that the antitumor effects of compound 7, which has an enlarged (7 carbon atoms) A-lactamic ring and nitrosourea esterified at the position 17, which seems to be the most appropriate for the connection of a DNA cross-linking amino acid derivative is superior.

Combinational effect of topotecan and octreotide on murine leukemia cells in vivo and in vitro.

PURPOSE: The activity of topotecan (TPT) against a number of hematological malignancies is now notably increased. TPT is a drug which inhibits the DNA enzyme topoisomerase I (topo I), thereby leading to the induction of tumor cell apoptosis. On the other hand, octreotide (OCT) is a synthetic analogue of somatostatin, which can induce apoptosis and antiproliferative effects on various human tumor cell lines, human xenografts and animal tumors, as well as on lymphoproliferative neoplasms. Hereby, we studied the effects of TPT and OCT, and their combination in the treatment of the rodent P388 lymphocytic leukemia, in vitro and in vivo. MATERIALS AND METHODS: Cell cultures of P388 lymphocytic leukemia cells, as well as BDF1 male and female mice implanted with the P388 leukemia cells, were used for the in vitro and in vivo evaluation of the antineoplastic activity of OCT and TPT. RESULTS: A significant increase of antileukemic activity of the combined treatment with both TPT and OCT was demonstrated. These results suggest that OCT enhances the effectiveness of TPT in the treatment of leukemia. CONCLUSION: Our results indicate that the combination of OCT with TPT in the treatment of hematological neoplasias is effective, and represents an interesting addition to the future therapeutic options, because os its mechanism of action and its toxicity profile.

Synergistic interaction between a mixed ligand copper (II) chelate complex and two anticancer agents in T47D human breast cancer cells in vitro.

PURPOSE: We have developed a copper(II) chelate complex with a tridentate ONN-Schiff ligand and the anion of salicylate, showing a potent cytotoxic activity against a panel of human and murine cancer cell lines. In this experiment we have explored the combination effect between Cu(SalNEt(2))salicylate (Cu-Sal) complex and two widely used drugs in cancer chemotherapy, bleomycin (BLM) and 5-fluorouracil (5-FU), against T47D human breast cancer cells. Previous theoretical quantum-chemical studies of this complex and ass adducts with biological molecules elucidated the underlying mechanism of action of this complex. MATERIALS AND METHODS: Cells grown in adherence in 96-well microplates were exposed simultaneously to both agents for 48 h. During cytotoxicity was assessed via the XTT colorimetric assay. The combined drug interaction was assessed with the median-effect analysis and the combination index (CI). RESULTS: Concurrent treatment of cells with Cu-Sal complex and the chemotherapeutic drugs BLM and 5-FU and the antioxidant agent ascorbic acid (AsA) resulted mainly in synergistic interaction for most concentration ratios. CONCLUSION: Cu-Sal complex interacts synergistically with the chemotherapeutic drugs for most schedules of administration. These findings call for prompting to search for possible interaction of this complex with other cellular elements of fundamental importance in cell proliferation.

Octreotide neutralizes dexamethasone antitumor actions on P388 murine lymphocytic leukemia in vivo.

PURPOSE: A wide variety of human malignancies, including lymphoproliferative neoplasms, express somatistatin (SS) receptors (SS-R). SS induces apoptosis and exerts pronounced antiproliferative effects on various human tumors cell lines, human xenografts, and animal tumors including P388 lymphocytic leukemia. In patients with thymoma the combination of octreotide (OCT) with corticosteroids improves the overall response rate. It has been reported that SS can increase glucocorticoid activity. Hereby, we studied the in vitro and in vivo activity of the SS analogue OCT and of the glucocorticoid dexamethasone (DEX) alone or in combination against the murine P388 lymphocytic leukemia. MATERIALS AND METHODS: Cultures of P388 lymphocytic leukemia and BDF(1) male mice implanted with P388 cells where used for the in vitro an in vivo evaluation of the antileukemic activity of SS and DEX. RESULTS: OCT induced a moderate and DEX a satisfactory cytostatic effect in vitro. OCT produced borderline antileukemic effect when administered on days 1-5 while DEX was effective in all schemes and routes of administration. However, none of the combination schemes exerted any anti-leukemic activity both in vitro and in vivo. CONCLUSION: Since both SS and glucocorticoids exert direct (via receptors) and indirect antitumor actions (regulation of growth factor activity) on several cell lines, in vitro and in vivo, it becomes obvious that further in vitro studies shall provide the molecular evidence for the signal transduction pathways which are involved in the interactions of such important anticancer drugs. Based on the results of the present study, the simultaneous use of these drugs in clinical practice should be carefully considered.

Synergistic interaction between a novel mixed ligand copper(II) chelate complex and a panel of anticancer agents in T47D human breast cancer cells in vitro.

PURPOSE: We have developed a novel copper(II) chelate complex with a tridentate ONN-Schiff base ligand and the anion of salicylate, which presented a potent cytotoxic activity against a panel of human and murine cancer cell lines. In this experiment we explored the combined effect between Cu(SalNEt(2))salicylate (Cu-Sal) complex and the widely used anticancer drugs carboplatin (CBDCA), cyclophosphamide (CTX) and paclitaxel (TXL) against T47D human breast cancer cells. Theoretical (quantum-chemical) study of this complex and its adducts with biological molecules were carried out, aiming at the elucidation of the underlying mechanism of action. MATERIALS AND METHODS: Cells grown in adherence in 96-well microplates were exposed simultaneously to both agents for 48 h. Drug cytotoxicity was assessed via the XTT colorimetric assay. The combined drug interaction was assessed with the median-effect analysis and the combination index (CI). RESULTS: Copper(II) salicylate complex was proved active against T47D human breast cancer cells. Concurrent treatment of cells with Cu-Sal complex and the chemotherapeutic drugs CBDCA, CTX and TXL, mainly showed a synergistic interaction in most concentration ratios. CONCLUSION: Cu-Sal complex interacts synergistically with tested chemotherapeutic drugs for most schedules of administration, and only occasionally an additive or antagonistic effect was apparent. With the aid of quantum-chemical calculations it was demonstrated that the mechanism of action of this complex involves binding to DNA and RNA. These findings prompt to search for possible interaction of this complex with other cellular elements of fundamental importance in cell proliferation.

A preclinical survey on the efficacy of lactandrate in the treatment of colon carcinoma.

PURPOSE: There has been a recent and dramatic increase in the pace of drug development for colorectal cancer which holds promise to further improve curative therapy. We tested lactandrate, an alkylating ester of D-lactam androsterone, for antineoplastic activity against colon adenocarcinoma in vitro and in vivo. MATERIALS AND METHODS: The cytostatic and cytotoxic activity of lactandrate were evaluated in vitro against 9 human colon adenocarcinoma cell lines. The in vitro testing was performed with the sulforhodamine B (SRB) colorimetric assay and the mean concentrations of each drug that generated 50% (GI50) or total (100%) growth inhibition (TGI), as well as the drug concentrations that produced cytotoxicity against 50% of the cultured cells (IC50) were calculated. The in vivo antitumour effect was determined against two rodent colon carcinomas, the Colon 26 and the relatively chemoresistant Colon 38 carcinoma, as well as against the human xenograft CX-1 colon carcinoma. RESULTS: Lactandrate displayed a satisfactory activity against the 9 human colon cancer cell lines, inducing significant growth inhibition and cytotoxicity. Lactandrate induced antiproliferative activity against colon cancer cell lines linearly correlated with the carcinoembryonic antigen (CEA) production. There was a non-linear polynomial correlation between CEA production and the cytotoxic effect of lactandrate. The more differentiated cell lines DLD-1 and HCC2998 appeared more resistant to the cytostatic effect of lactandrate. In vivo, the compound produced a significant antitumour activity against Colon 26 and Colon 38, as well as a moderate antitumour effect against CX-1 colon carcinoma. CONCLUSION: Preclinical research supports the high in vitro and in vivo antitumour potential of lactandrate against colon carcinoma. Therefore, lactandrate represents an important candidate drug for further clinical development.

Cytotoxic effects of a mixed ligand copper(II) chelate complex against a panel of human and murine cancer cells in vitro. Theoretical study of the mechanism of biologic action through molecular modelling.

PURPOSE: In an effort to discover new compounds with anticancer activity, we have developed a novel copper (II) [Cu(II)] chelate complex with a tridentate ONNSchiff base ligand and the anion of salicylate and we evaluated the in vitro chemosensitivity of various human and murine tumor cell lines by measuring cell growth inhibition. The ultimate goal was to evaluate the existence of a potential antitumor activity of this complex. Beyond the cytotoxic activity assessment of the complex, we aimed at the elucidation of the underlying mechanism of action of this complex and its interactions with biological molecules, carrying out theoretical (quantum-chemical) calculations. MATERIALS AND METHODS: Cells grown in adherence or in suspension in 96-well microplates were exposed to Cu(II) complex for 24, 48 or 72 h. In vitro drug cytotoxicity was assessed by SRB and XTT colorimetric assays. Molecular modelling tools were used applying semiempirical and ab initio calculations. RESULTS: A series of experiments was carried out, showing a potent cytotoxic activity against most of the tested cancer cell lines. Quantum-chemical calculations demonstrate that the mechanism of the cellular damage can be explained, at least in part, by the ability of the nucleobases and nucleotides to be subject to nucleophilic attack on copper. CONCLUSION: Profound growth inhibitory effects were observed for the tested Cu(II) complex. It was also verified the hypothesis that the mechanism of action of this complex involves binding to DNA and RNA. These findings prompt to search for possible interaction of this complex with other cellular elements of fundamental importance for cell proliferation.

A comparative study on cytogenetic and antineoplastic effects induced by two modified steroidal alkylating agents.

We investigated the effects of two newly synthesized steroidal derivatives of nitrogen mustard on sister chromatid exchange rates and on human lymphocyte proliferation kinetics. The compound 33-hydroxy-5alpha,22alpha-spirostan- 12-one-p-(N,N-bis(2-chloroethyl)amino)phenylacetate(1) was, on a molar basis, less effective in inducing sister chromatid exchange and suppressing cell proliferation rate indices than compound 3beta-hydroxy-12alpha-aza-C-homo-5alpha,22alpha-spirostan-12-one-p-(N,N-bis(2-chloroethyl)amino)phenylacetate(2). A correlation was observed between the magnitude of the sister chromatid exchange response and the depression of cell proliferation index. We also studied the effects of the aforementioned compounds on Lewis lung carcinoma. The order of the percent inhibition of tumor growth achieved by the compounds coincides with the order of the cytogenetic effects they induce.

Antitumor activity of L-asparaginase from Thermus thermophilus.

L-asparaginase (EC 3.5.1.1) was purified to homogeneity from Thermus thermophilus. The apparent molecular mass of L-asparaginase was found to be 33 kDa by SDS-PAGE, whereas by Sephacryl S-300 superfine column it was found to be 200 kDa, indicating that the enzyme in the native stage acts as hexamer. It is a thermostable enzyme and keeps all of its activity at 80 degrees C for 10 min. The antiproliferative activity of the purified L-asparaginase from T. thermiphilus was tested against the following human cell lines: K-562 (chronic myelogenous leukemia), Raji (Burkitt's lymphoma), SK-N-MC (primitive neuroectodermal tumor), HeLa (cervical cancer), BT20 and MCF7 (breast cancers), HT-29 (human colon cancer), and OAW-42 (ovarian cancer). The antiproliferative activity of T. thermophilus enzyme was compared with Erwinase, the commercially available L-asparaginase from Erwinia corotovora. The potency difference between the two L-asparaginases was greater in HeLa and SK-N-MC than in other cell lines. The fact that L-asparaginase from T. thermophilus does not hydrolyse L-glutamine makes it advantageous for future clinical trials.