Effects of the ruthenium-based drug NAMI-A on the roles played by TGF-ß1 in the metastatic process.

The ruthenium-based drug NAMI-A, characterised by its selectivity against solid tumour metastases, promotes TGF-ß1-dependent fibrosis and the reduction of the release of MMPs in the primary tumour. The aim of the study was to examine the interaction of NAMI-A with TGF-ß1 in the process of metastasis formation. NAMI-A (1) affects the secretion of TGF-ß1 in metastatic MDA-MB-231 cells rather than in non-tumorigenic HBL-100 cells, (2) prevails over TGF-ß1 with regard to the invasive capacity of the treated cells, and (3) contrasts integrin-dependent migration stimulated by TGF-ß1. It, thus, appears that the effects of NAMI-A on cell invasion and migration are best summarised as an interference with TGF-ß1 and a reduction of its activity in these events. At a molecular level, the similar activity of NAMI-A and TGF-ß1 on RhoA GTPase supports its interaction with cell surface integrins while TGF-ß1 can activate it by interaction with its TGFßR receptor. The inhibition of TGF-ß1-induced migration of MDA-MB-231 cells by NAMI-A cannot simply be attributed to a modulation of the Smad2 and p38MAPK pathways. In conclusion, the effects of NAMI-A on the biological role of TGF-ß1 in cancer metastasis are insufficient to attribute the responsibility for the anti-metastatic activity of the ruthenium-based drug to this target alone.

The antimetastatic drug NAMI-A potentiates the phenylephrine-induced contraction of aortic smooth muscle cells and induces a transient increase in systolic blood pressure.

The ruthenium-based drug imidazolium trans-imidazoledimethylsulphoxidetetrachlorido ruthenate (NAMI-A) is a novel antitumour drug under clinical evaluation. In this study, NAMI-A is tested on aortic rings in vitro and on the systolic blood pressure in vivo with the aim of evaluating its effects on smooth muscle cells and, more in general, on the vascular system. Pre-incubation of aortic rings with 10 µM NAMI-A for 10 min potentiates the contraction induced by phenylephrine (PE). The reduction of the B max value of [(3)H]-prazosin bound to NAMI-A-treated aortic rings and the ability of NAMI-A to displace [(3)H]-prazosin and [(3)H]-IP3 binding by 25 and 42%, respectively, suggest the involvement of α1-adrenoceptor in mediating the effects on smooth muscle cells. NAMI-A also decreases the number of maximal sites of [(3)H]-prazosin bound to kidney membrane preparation from 34 to 24 fmol/mg proteins. A single i.p. dose (105 mg/kg) or a repeated treatment for 6 consecutive days (17 mg/kg/day) in Wistar rats increases the systolic blood pressure, respectively, 1 h and 3 days after treatment, and the responsiveness of rat aortic rings to PE. Atomic absorption spectroscopy confirms the presence of ruthenium in the aortic rings excised from the treated rats. These findings suggest monitoring the cardiovascular parameters when the drug is used in humans for treating cancer patients, particularly if the drug is associated with chemicals that are potentially active at the cardiovascular level.

Chitosan-coated alginate micro-particles delivery of active principles through conventional pelleted food - A study in Tilapia (Oreochromis niloticus).

The search for alternatives to antibiotics in aquaculture has focused on the use of vaccines for immune-prophylaxis. The purpose of this study was to examine the feasibility and characteristics of chitosan-alginate microparticles for the oral delivery of immune-prophylactics to finfish. The microparticles, which incorporate fluorescent-labelled lysozyme, were produced by spray-drying method; their structural properties and uptake from the gastrointestinal tract of Tilapia (Oreochromis niloticus) were assessed by microscopy. The main findings show that the microparticles are able to retain their content in an acidic environment and to release it later in slightly alkaline conditions such as those found in the intestines. Moreover, both the microencapsulation procedure and the biopolymers used have no deleterious impact on the lysozyme lytic activity, which is maintained after the protein has been released from the microparticles. Administered in vivo in Tilapia by medicated food, the microparticles transit unaffected through the stomach, and reach the anterior intestines, in particular the villum sectum and the basal lamina of epithelial cells, 2 and 4 h after feeding. Overall, the evidence obtained here supports the potential of these chitosan-alginate microparticles as agents for oral immune-prophylaxis in the management of fish diseases.

Good Manufacturing Practice for Medicinal Products in Bulgaria: an Analysis of Regulatory Inspection Findings.

BACKGROUND: The manufacture of medicinal products for human use in the European Economic Area is governed by European Directives and Regulations stipulating the relevant principles and guidelines of Good Manufacturing Practice, describing the minimum standard to be fulfilled in the production processes. AIM: To present analysis of the deficiencies reported following Good Manufacturing Practice inspections in Bulgaria in two consecutive years (2016, 2017) and to compare them with results from similar inspections reported by other EU member states. MATERIALS AND METHODS: A retrospective study was carried out by reviewing the complete Good Manufacturing Practice inspection reports of all manufacturers conducted by the Bulgarian Drug Agency in 2016 and 2017, according to relevant requirements and applicable local legislation. The items reviewed were scope of inspection, type of companies, classification of deficiencies ­ 'critical', 'major' and 'other significant deficiencies', their nature and reference to EU Good Manufacturing Practice. RESULTS: The analyzed data included 55 inspections, revealing 460 various deficiencies, of which 2 were critical and 102 ­ major. Twenty inspections were performed in 2016 vs. 35 inspections in 2017. The pattern of deficiencies was similar to the findings of other EU regulatory agencies, showing that equivalent requirements were applied. Our analysis showed that Bulgarian Drug Agency inspectors rarely raised deficiencies related to Computer Systems, Qualification/Validation, Personnel and Qualification of Suppliers unlike other EU regulators agents. CONCLUSIONS: Our analysis of Good Manufacturing Practice inspection findings in 2016 and 2017 showed that the Bulgarian Drug Agency demonstrated its ability to detect non-compliances and take necessary regulatory actions. Quality related issues constitute the main reasons for non-compliances with the requirements.

Orally administered microencapsulated lysozyme downregulates serum AGE and reduces the severity of early-stage diabetic nephropathy.

AIM: Diabetic nephropathy is the leading cause of end-stage kidney disease in developed countries and is related to chronic hyperglycaemia. The increased production and tissue deposition of advanced glycation end products (AGE) are known to play a major role in the pathogenesis of diabetic kidney damage. This study was undertaken to determine if lysozyme (LZ), microencapsulated in orally administrable chitosan-coated alginate microspheres (MS), is effective against the early changes seen in the initial stages of diabetic nephropathy. METHODS: LZ-containing MS (MSLZ) and an equivalent dose (equidose) of nonencapsulated LZ were given as oral treatments. LZ was administered to Wistar rats for seven weeks after diabetes induction with streptozotocin. RESULTS: The results showed that microencapsulated LZ treatment significantly reduced the concentration of serum AGE in the circulation and their deposition in the kidneys. Likewise, MSLZ significantly prevented the development of microalbuminuria compared with untreated diabetic rats. Furthermore, MSLZ significantly prevented the development of glomerular and renal hypertrophy as well as overexpression of AGE receptors (RAGE). An equidose of free LZ had little or no effect whatsoever. CONCLUSION: Our study supports a relationship between serum AGE and nephropathy in diabetes, and suggests that orally administered microencapsulated LZ can exert kidney-protective activity in a diabetic animal model.

A novel retinoic/butyric hyaluronan ester for the treatment of acute promyelocytic leukemia: preliminary preclinical results.

All-trans retinoic acid (ATRA) represents the therapy of choice for patients with acute promyelocytic leukemia (APL). However, patients often relapse due to ATRA-resistance. The molecular basis of APL alterations indicates that addition of a histone deacetylase inhibitor to ATRA may restore the sensitivity to retinoids. We explored the in vitro and in vivo effects of a novel retinoic/butyric hyaluronan ester (HBR) on a retinoic acid (RA)-sensitive human myeloid cell line, NB4, and on its RA-resistant subclone, NB4.007/6. In vitro, HBR induced growth arrest and terminal differentiation in RA-sensitive NB4 cells (as confirmed by an increased expression of CD11 family members and nitroblue tetrazolium assay), whereas it inhibited the growth of RA-resistant cells by apoptosis, paralleled by an increase in the levels of caspase 3 and 7. In vivo, HBR treatment of NB4-inoculated severe combined immunodeficient mice resulted in a statistically significant increase in survival time (P<0.0001), comparable to that induced by a maximum tolerated dose of RA alone. Also on P388-inoculated mice, HBR was active in contrast to RA that was completely ineffective. Present findings suggest that, owing to the simultaneous presence of RA and an histone deacetylases inhibitor, HBR might be useful in controlling the proliferation of RA-resistant cells and the differentiation of RA-sensitive cells.

Antimetastatic effects of N-diazoacetyl-glycine derivatives in C57BL mice.

When three diazoacetyl-glycine derivatives, N-diazoacetyl-glycine amide (DGA), N-diazoacetyl-glycine hydrazide (DGI), and N-diazoacetyl-glycine ethyl ester (DGE), were tested against Lewis lung carcinoma in C57BL mice, DGA reduced sharply the number and weight of pulmonary metastases; the effects of DGI and DGE were less pronounced. The growth of the primary tumor was reduced slightly by DGA, but the greater effect was produced by DGI. The absence of correlation between the reduction of the growth of the primary implant and the number of lung secondary tumors for the tested compounds indicated that DGA possesses antimetastatic properties.

Antimetastatic action and hematological toxicity of p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt and 5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide used as prophylactic adjuvants to surgical tumor removal in mice bearing B16 melanoma.

The treatment of mice bearing i.m. B16 melanoma with equitoxic dosages of the clinically used 5-(3,3-dimethyl-1-triazeno)-imidazole-4-carboxamide (DTIC) and of its benzenoid water-soluble analogue p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (DM-COOK) prior to surgical tumor removal results in a remarkable proportion of cures, even when the treatment is started on already palpable tumors for which surgery alone is ineffective. The survival time of mice which are not cured is also significantly increased with DM-COOK. At the same time, DM-COOK does not affect artificial metastases or spontaneous metastases in mice undergoing surgery and treated with DM-COOK postoperatively. Inhibition of i.m. tumor growth in surgical experiments, and of s.c. tumors in mice not treated with surgery, is significant, although not as pronounced as is necessary to obtain significant prolongation of the life span of the host; the survival time of mice with s.c. tumors treated with both drugs is indeed not significantly increased. DM-COOK thus appears to exert selective antimetastatic effects, unrelated to cytotoxicity for tumor cells, against B16 melanoma in addition to those reported for Lewis lung carcinoma and M5 ovarian reticular cell sarcoma; its therapeutic usefulness is evidenced in adjuvant surgical experiments. DM-COOK, unlike DTIC, is devoid of hematological toxicity for the host. Since, in leukemic mice, it is at least as active as DTIC in increasing the life span of the treated animals, it appears to be an advantageous substitute for DTIC that could undergo preliminary clinical trial.

Selectivity of the antimetastatic and cytotoxic effects of 1-p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (+/-)-1,2-di(3,5-dioxopiperazin-1-yl)propane, and cyclophosphamide in mice bearing Lewis lung carcinoma.

The effects of two selective antimetastatic agents, 1-p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (DM-COOK), and (+/-)-1,2-di(3,5-dioxopiperazin-1-yl)propane, have been examined in comparison with those of a cytotoxic agent, cyclophosphamide, in mice bearing Lewis carcinoma. Cyclophosphamide at the two highest dosages causes a strictly related and pronounced inhibition (to less than 10%) of the weight of the s.c. tumor, spontaneous metastases, and lung colonies formed after i.v. injection of tumor cells (artificial metastases); this behavior is consistent with a purely cytotoxic mechanism. At the three dosages used, (+/-)-1,2-di(3,5-dioxopiperazin-1-yl)propane reduces the weight of spontaneous metastases to less than 3%. A dose-dependent reduction of artificial metastasis weight is also observed. At the highest dose, artificial metastasis weight is reduced to about 5%, and s.c. tumor mass is significantly lowered to 40%. These effects are consistent with the combined occurrence of cytotoxic and selective antimetastatic action, although the latter appears to be predominant. At the three dosages used, DM-COOK markedly depresses the weight and number of spontaneous metastases to about 10%, leaving the formation of artificial metastases unaffected and causing no significant effect on primary tumor growth. The effects of these agents on the fractional incorporation of [3H]thymidine in tumor cells further indicate that only DM-COOK is devoid of cytotoxic effects for pulmonary and s.c. tumors. In hosts pretreated with DM-COOK, no reduction in the formation either of spontaneous or of artificial metastases is observed. These data indicate that DM-COOK acts directly on tumor cells and that it presumably inhibits their release from the primary tumor into the bloodstream.

Influence of the binding of reduced NAMI-A to human serum albumin on the pharmacokinetics and biological activity.

NAMI-A is a ruthenium-based drug endowed with the unique property of selectively targeting solid tumour metastases. Although two clinical studies had already been completed, limited information exists on the behavior of NAMI-A after injection into the bloodstream. PK data in humans informs us of a rather low free drug concentration, of a relatively high half-life time of elimination and of a linear relationship between the administered dose and the corresponding AUC for up to toxic doses. In the present study, we examined the chemical kinetics of albumin binding with or without the presence of reducing agents, and we evaluated how these chemical aspects might influence the in vivo PK and the in vitro ability of NAMI-A to inhibit cell migration, which is a bona fide, rapid and easy way to suggest anti-metastatic properties. The experimental data support the binding of NAMI-A to serum albumin. The reaction is facilitated when the drug is in its reduced form and, in agreement with already reported data, the adduct formed with albumin maintains the biological activity of the ruthenium drug. The formation of the adduct is favored by low ratios of NAMI-A : HSA and by the reduction of the drug with ascorbic acid. The difference in in vivo PK and the faster binding to albumin of the reduced NAMI-A seem to suggest that the drug is not rapidly reduced immediately upon injection, even at low doses. Most probably, cell and protein binding prevail over the reduction of the drug. This observation supports the thesis that the reduction of the drug before injection must be considered relevant for the pharmacological activity of NAMI-A against tumour metastases.

Antimetastatic action of orally administered lysozyme in mice bearing Lewis lung carcinoma.

The pharmacological activity of orally administered lysozyme, for the control of the growth of solid tumor metastases, was examined in mice bearing Lewis lung carcinoma. Groups of at least 10 tumor-bearing mice, fed daily for three consecutive weeks from subcutaneous tumor implantation with lysozyme, prepared from hen egg-white, had a pronounced reduction of the weight of their metastatic tumor to 25-50 per cent of controls within a wide range of doses (25-200 mg/kg/day). The antimetastatic effect was not related to the length of the treatment schedule employed; a short course of 7 days, given on days 1-7 after tumor implantation, proved equally active. The inhibition of the formation of lung metastases, in mice treated with lysozyme prior to tumor inoculation, lasts for at least 2 weeks after discontinuation of treatment, indicating that the antimetastatic activity observed is not associated with cytotoxic activity of the lysozyme, and is probably mediated by the elicitation of host responses. The examination of the therapeutic potential of the antimetastatic action of lysozyme supplied through the usual diet indicates that this treatment synergizes with the antitumor effects of cisplatin, given to mice after surgical removal of the primary tumor, causing a statistically significant prolongation of the survival time of the animals as compared with chemotherapy alone.

Na[trans-RuCl4(DMSO)Im], a metal complex of ruthenium with antimetastatic properties.

The antitumor and antimetastatic effects of a ruthenium(III) complex, Na[trans-RuCl4(DMSO)Im], have been examined in mice bearing MCa mammary carcinoma. Na[trans-RuCl4(DMSO)Im] is capable of reducing primary tumor growth and of prolonging the survival time with different schedules of administration. However, better effects were obtained (a) with treatments started soon after tumor implantation, (b) with daily administration rather than with treatments at 4-day intervals and (c) using relatively low daily doses. The prolongation of survival time in tumor-bearing hosts, greater than that obtained with cisplatin, cannot be simply related to the effect on primary tumor growth, always less than that of cisplatin. Rather, emphasis is placed on the reduction of lung metastasis formation, obtained either by i.v. injection of tumor cells (lung colonization or spontaneously from i.m. tumor implants, which is significantly greater than the reduction of primary tumor growth. The antimetastatic effect depends on the treatment schedule and is greater with low doses given daily than with high doses administrated with drug-free intervals. Metastasis reduction involved mainly large metastatic nodules, reducing the average weight of each metastasis by 8-fold for spontaneous metastases and by 5-fold for lung colonies. The antimetastatic action of Na[trans-RuCl4(DMSO)Im] thus indicates the possibility that related analogs can represent a new generation of antitumor compounds capable of selectively interacting with metastasis formation of solid tumors.

Antimetastatic action and toxicity on healthy tissues of Na[trans-RuCl4(DMSO)Im] in the mouse.

The ruthenium-dimethylsulfoxide complex Na(trans-RuCl4(DMSO)Im] was given i.v. to mice bearing MCa mammary carcinoma and its effects on tumor growth and on healthy host tissues were studied by macroscopic examination of primary tumor growth, by survival time, and by histological analysis using light microscopy and SEM. Either by means of vivo-vivo bioassays or by microscopic examination it appeared that the growth of lung tumors was markedly reduced, whereas the growth of the i.m. primary tumor was much less affected. These effects account for the prolongation of survival time and for the cure rate observed. The favourable effect on survival time was also influenced by the lack of significant cytotoxicity for normal tissues such as lung and kidney epithelia, muscle and liver cells, splenocytes and bone marrow. It thus appears that the selective interaction with tumor cells in the lungs cannot simply be attributed to a selectively higher localization of the compound at this site, nor to a modification of the histological structure of primary tumor. These results highlight the pharmacologic properties of this compound for the control of solid tumor metastases, an effect that was shown to be similarly exerted on advanced tumor metastases.

Effects of antimetastatic, antiinvasive and cytotoxic agents on the growth and spread of transplantable leukemias in mice.

The effects of cytotoxic (cyclophosphamide, CCNU, GANU), antiinvasive (vincristine, vinblastine) and antimetastatic (ICRF-159, DM-COOK) agents have been compared in mice-bearing P388 and L1210 leukemias, and TLX5 lymphoma. The drugs tested increase the survival time of the treated mice in a manner consistent with a cytotoxic action in the case of cyclophosphamide, CCNU, GANU, vincristine and vinblastine. Leukemic infiltration of the brain after i.p. tumor implantation has been determined by bioassay of this organ, and is reduced by treatment with all of the drugs tested, with the exception of ICRF-159. DM-COOK appears to increase the life-span of the treated animals by the inhibition of leukemic spread rather than by a cytotoxic action. The marked cytotoxicity of vincristine and vinblastine is sufficient to account for failure to detect any antimetastatic effects of these agents. The lack of antidisseminative effect observed for ICRF-159 under the experimental conditions employed might be connected with the observation that the antimetastatic action of this drug on solid tumors is due to its effects on tumor blood vessels.

Antimetastatic action of the prostacyclin analog iloprost in the mouse.

The antimetastatic activity of the prostacyclin analog Iloprost has been examined in mice bearing Lewis lung carcinoma. An inhibition of lung colony formation is observed when 100 or 200 micrograms/kg Iloprost are administered i.v. 1 h before i.v. injection of tumor cells, which is dependent on the size of tumor inoculum. The effects of 200 micrograms/kg Iloprost persist for 24 h, and are of the same magnitude as those obtained with 10 mg/kg prostacyclin, which last only for 30 min. When treatment with Iloprost is followed by surgical removal of primary tumor, spontaneous metastasis formation is reduced, and the survival time of the treated animals is significantly increased over controls treated with surgery only. The antimetastatic effects of Iloprost appear dissociated from drug's effects on the hemostatic system of the host as indicated by the clot retraction assay, performed after in vivo treatment, using ADP or tumor cells as platelet aggregating agents. Iloprost thus appears to reduce spontaneous metastasis formation and intraoperative tumor cell dissemination, with pharmacological properties more favourable to therapeutic use than those of prostacyclin.

Effects of DTIC, DM-COOK and ICRF-159 on the number of circulating Lewis lung carcinoma cells detected by flow cytometry.

Circulating tumor cells can be detected by means of flow cytometry in the blood of mice bearing i.m. Lewis lung carcinoma. This technique can be applied in the case of aneuploid tumors and does not require either concentration of nucleated cells or other processing of the blood samples. It offers the advantages of simplicity and speed and allows quantitative measurement of the number of circulating tumor cells. It can be applied to the study of the effects of drug treatment on the number of circulating tumor cells, for those drugs which do not cause alterations in the nuclear DNA content of normal diploid blood cells. The number of circulating tumor cells determined by flow cytometry is markedly reduced by treatment with ICRF-159, by dimethyltriazene DM-COOK, and also by its clinically used analog, DTIC.

Pharmacological control of lung metastases of solid tumours by a novel ruthenium complex.

Imidazolium trans-imidazoledimethylsulphoxidetetrachlororuthenate ImH[trans-RuCl4(DMSO)Im] (NAMI-A), a ruthenium compound that replaces Na+ with ImH+ in the molecule of Na[trans-RuCl4(DMSO)Im] (NAMI), was studied for the anti-metastasis effects in models of solid metastasizing tumours of the mouse. NAMI-A, given i.p. at 35 mg/kg/day for six consecutive days, a dose equimolar to that of NAMI, to mice bearing Lewis lung carcinoma and MCa mammary carcinoma, markedly reduces lung metastasis weight by 80-90%, with an effect equal or even superior to that of NAMI, depending on the experimental system adopted. Correspondingly, NAMI-A increases the content of connective tissue in the tumour matrix, around blood vessels, and in the tumour capsule, augments the percentage of tumour cells in G2/M phase and reduces the amount of CD45+ cells infiltrating the tumour parenchyma. The effects of the same doses on spleen lymphocytes correspond to an increase of CD8+ subset without any change of the distribution of cells in G0/G1, S and G2/M phases. The study shows that NAMI-A behaves similarly to NAMI on the several parameters examined in comparison experiments and therefore we suggest to credit NAMI-A with all the biological actions already described for NAMI during the last 3 years. The replacement of Na+ with ImH+ therefore, besides the better chemical stability of the molecule, confers to [trans-RuCl4(DMSO)Im]- a closer similarity with a true drug to be used in humans, and suggests this molecule for future studies of preclinical toxicology and phase I and II clinical trials.

Anti-leukaemic action of RuCl2 (DMSO)4 isomers and prevention of brain involvement on P388 leukaemia and on P388/DDP subline.

Two ruthenium(II) complexes, characterised by the presence of dimethylsulphoxide ligands, were investigated in comparison to cisplatin on mouse P388 leukaemia and on a subline made resistant to cisplatin (P388/DDP). Both cis- and trans-RuCl2(DMSO)4 significantly prolonged the survival time of leukaemic mice, independently of the tumour line used. Unlike cisplatin, the prolongation of life-span of tumour-bearing hosts caused by ruthenium complexes was not supported by a parallel inhibition of the number of tumour cells in the treated hosts, as evidenced by tumour cell count in the peritoneal cavity and by vivo-vivo bioassays of blood samples and of whole brains. Thus, cis- and trans-RuCl2(DMSO)4 appear capable of preventing leukaemic spread into the central nervous system also when the number of tumour cells in the peritoneal cavity and in the blood stream is as high as in untreated controls. When the drug-induced DNA damage was investigated by modifying double stranded DNA and identifying the lesions able to inhibit DNA synthesis in vitro, trans-RuCl2(DMSO)4 and, to a lesser extent, cis-RuCl2(DMSO)4 formed blocking lesions at the same sites of cisplatin; nevertheless, the mechanism of antitumour activity of ruthenium complexes appears to be different from that of cisplatin for the absence of any relationship between cytotoxicity and prevention of leukaemic dissemination into the central nervous system. These data indicate that the activity of cis- and trans-RuCl2(DMSO)4 on the P388 leukaemia is characterised by the lack of cross-resistance with cisplatin and by the alteration of the metastasising behaviour of leukaemic cells which lose their natural capacity to invade the central nervous system.

Actin-dependent tumour cell adhesion after short-term exposure to the antimetastasis ruthenium complex NAMI-A.

Imidazolium trans-imidazoledimethylsulphoxidetrachlororuthenate (NAMI-A) was tested in vitro on the pro-adhesive properties, evaluated as resistance to trypsin treatment, which is a bona fide measure of adhesion strength, of KB and HeLa carcinoma cell lines and on human polymorphonuclear neutrophils (HPMN). NAMI-A increased the pro-adhesive activity of KB cells at 0.001 mM concentration, after few minutes incubation and this effect was not influenced by the vehicle used for cell challenge, neither did it depend on NAMI-A concentration or on temperature. The same effect occurred on HeLa cells at 0.01 mM NAMI-A. This effect, detected at concentrations up to 100 times lower than those necessary to block cells at the G(2)-M premitotic phase of cell cycle, or to inhibit matrix metalloproteinase release or cell invasion, was not related to ruthenium uptake by tumour cells. HeLa cells and healthy HPMN, following short exposure to 0.1 mM NAMI-A, assumed a different shape, with the extrusion of filopodia (HeLa) and of large lamellopodia (HPMN), which increased their interactions with the substrate. This effect was attributed to stabilisation, altered turnover and sensitivity to cytochalasin D of actin filaments. Provided that adhesion is associated with cell motility and invasion, these data suggest that NAMI-A may exert antimetastatic properties at concentrations lower than those observed in the lungs at the end of a conventional intraperitoneal treatment in vivo.

Influence of chemical stability on the activity of the antimetastasis ruthenium compound NAMI-A.

The influence of chemical stability on the antimetastatic ruthenium(III) compound imidazolium trans-imidazoletetrachlorodimethylsulphoxideruthenium(III) (NAMI-A) in aqueous solution was studied both in vitro and in vivo. The loss of dimethyl-sulphoxide (DMSO) ligand from the compound was tested by using a NAMI-A solution acidified with HCl at pH 3.0 and aged for 0, 4, 8 and 24 h prior to intraperitoneal (i.p.) injection into CBA mice bearing advanced MCa mammary carcinoma. The activity of NAMI-A on lung metastases showed no change even after the loss of DMSO ligand from up to 50% of the molecules. The reduction of NAMI-A did not modify the number of KB cells blocked in the S+G2M phases, independent of whether the reduction occurred outside the cells or after loading the cells with the compound prior to treatment with the reductants (ascorbic acid, glutathione or cysteine). In vivo, the complete reduction of NAMI-A with equivalent amounts of ascorbic acid, glutathione or cysteine prior to administration to mice bearing advanced MCa mammary carcinoma was more active than NAMI-A alone. The data show that NAMI-A, although undergoing a series of chemical modifications, maintains its antimetastatic activity in a broad range of experimental conditions.