New ruthenium(II) complexes with cyclic thio- and semicarbazone: evaluation of cytotoxicity and effects on cell migration and apoptosis of lung cancer cells.

We describe the synthesis, physicochemical characterization, and in vitro antitumor assays of four novel analogous ruthenium(II) complexes with general formula cis-[RuII(N-L)(P-P)2]PF6, where P-P = bis(diphenylphosphine)methane (dppm, in complexes 1 and 2) or bis(diphenylphosphine)ethane (dppe, in complexes 3 and 4) and N-L = 5,6-diphenyl-4,5-dihydro-2H-[1,2,4]triazine-3-thione (Btsc, in complexes 1 and 3) or 5,6-diphenyltriazine-3-one (Bsc, in complexes 2 and 4). The data were consistent with cis arrangement of the biphosphine ligands. For the Btsc and Bsc ligands, the data pointed to monoanionic bidentate coordination to ruthenium(II) through N,S and N,O, respectively. Single-crystal X-ray diffraction showed that complex 1 crystallized in the monoclinic system, space group P21/c. Determination of the cytotoxicity profiles of complexes 1-4 gave SI values ranging from 1.19 to 3.50 against the human lung adenocarcinoma cell line A549 and the non-tumor lung cell line MRC-5. Although the molecular docking studies suggested that the interaction between DNA and complex 4 was energetically favorable, the experimental results showed that they interacted weakly. Overall, our results demonstrated that these novel ruthenium(II) complexes have interesting in vitro antitumor potential and this study may contribute to further studies in medicinal inorganic chemistry.

Anti-melanoma effect of ruthenium(II)-diphosphine complexes containing naphthoquinone ligand.

The use of natural products as potential ligands has been explored as a strategy in the development of metal-based chemotherapy. Since ruthenium complexes are promising alternatives to traditional antitumor agents, this study evaluated the anti-melanoma potential of two ruthenium(II) complexes containing the naphthoquinone ligands lapachol (lap), [Ru(lap)(dppm)2]PF6, and lawsone (law), [Ru(law)(dppm)2]PF6, in addition to the bis(diphenylphosphino)methane (dppm) ligand, referred to as complexes (1) and (2), respectively, using a syngeneic murine melanoma model. Activation of the apoptotic pathway by the treatments was assessed by immunohistochemistry in tumor tissue. Additionally, toxicity of the treatments was evaluated by variation in body and organ weight, quantification of biochemical indicators of renal damage, and genotoxicity in bone marrow and hepatocytes. First, the antiproliferative activity of (1) and (2) was observed in B16F10 cells, with IC50 values of 2.78 and 1.68 µM, respectively. The results obtained in mice showed that, unlike complex (1), (2) possesses significant anti-melanoma activity demonstrated by a reduction in tumor volume and mass (88.42%), as well as in mitosis frequency (83.86%). Additionally, complex (2) increased the levels of cleaved caspase-3, inducing tumor cell apoptosis. When compared to the metallodrug cisplatin, complex (2) exhibited similar anti-melanoma activity and lower toxicity considering all parameters evaluated. In silico studies demonstrated no difference in the binding energy of the naphthoquinone complex between complexes (1) and (2). However, the complex containing the lawsone ligand has a lower molar volume, which may be important for interactions with minor DNA grooves. The present results demonstrate the antitumor efficiency of complex (2) and a significantly lower systemic toxicity compared to cisplatin.

Evaluation of the antiseptic and wound healing potential of polyhexamethylene guanidine hydrochloride as well as its toxic effects.

The synthetic polyhexamethylene guanidine hydrochloride (PHMGH) polymer presents antifungal and antimicrobial activities in vitro. However, in vivo reports regarding its antiseptic and healing activity are scarce in the scientific literature. Thus, the present study aimed to evaluate the antimicrobial and healing effects, as well as toxicological parameters, of a topical solution containing 0.5% PHMGH (Akwaton®) in the treatment of superficial skin wounds experimentally induced on the dorsum of rodents. In addition, non-clinical safety studies were also conducted for use in human health, such as acute oral toxicity and genotoxicity tests. Animals did clinically not present dermatitis. After two days of topical treatment, PHMGH showed a significant antiseptic effect compared to the untreated group, reducing the number of colony-forming units by 72%, reaching 100% on the fourth day of treatment. The animals treated with PHMGH showed a significant area reduction of the skin lesions in relation to the untreated group, indicating a healing effect of the polymer. Moreover, PHMGH treatment led to a significant increase in fibroblasts when compared to the untreated group, revealing its healing action. No significant differences were observed between the biochemical indicators of hepatoxicity and nephrotoxicity, nor genotoxicity between the PHMGH-treated and the negative control groups. The results of acute oral toxicity showed that PHMGH at 5% presents a lethal dose 50% greater than the 2000 mg/kg. At a concentration of 5%, PHMGH did not show genotoxicity nor cytotoxicity at doses up to 1500 mg/kg through the micronucleus assay in mice. Therefore, 0.5% PHMGH showed an antimicrobial and healing effect, with no toxicity, and could be a promising adjunct in the microbial control of healing wounds.

Manool, a diterpene from Salvia officinalis, exerts preventive effects on chromosomal damage and preneoplastic lesions.

The present study aimed to evaluate the effect of the manool diterpene on genomic integrity. For this purpose, we evaluated the influence of manool on genotoxicity induced by mutagens with different mechanisms of action, as well as on colon carcinogenesis. The results showed that manool (0.5 and 1.0 µg/ml) significantly reduced the frequency of micronuclei induced by doxorubicin (DXR) and hydrogen peroxide in V79 cells but did not influence genotoxicity induced by etoposide. Mice receiving manool (1.25 mg/kg) exhibited a significant reduction (79.5%) in DXR-induced chromosomal damage. The higher doses of manool (5.0 and 20 mg/kg) did not influence the genotoxicity induced by DXR. The anticarcinogenic effect of manool (0.3125, 1.25 and 5.0 mg/kg) was also observed against preneoplastic lesions chemically induced in rat colon. A gradual increase in manool doses did not cause a proportional reduction of preneoplastic lesions, thus demonstrating the absence of a dose-response relationship. The analysis of serum biochemical indicators revealed the absence of hepatotoxicity and nephrotoxicity of treatments. To explore the chemopreventive mechanisms of manool via anti-inflammatory pathways, we evaluated its effect on nitric oxide (NO) production and on the expression of the NF-kB gene. At the highest concentration tested (4 µg/ml), manool significantly increased NO production when compared to the negative control. On the other hand, in the prophylactic treatment model, manool (0.5 and 1.0 µg/ml) was able to significantly reduce NO levels produced by macrophages stimulated with lipopolysaccharide. Analysis of NF-kB in hepatic and renal tissues of mice treated with manool and DXR revealed that the mutagen was unable to stimulate expression of the gene. In conclusion, manool possesses antigenotoxic and anticarcinogenic effects and its anti-inflammatory potential might be related, at least in part, to its chemopreventive activity.

Influence of Asiatic acid on cell proliferation and DNA damage in vitro and in vivo systems.

Asiatic acid (AA) is a triterpene with promising pharmacological activity. In the present study, in vitro and in vivo assays were conducted to understand the effect of AA on cell proliferation and genomic instability. AA was cytotoxic to human tumor cell lines (M059J, HeLa, and MCF-7), with IC50 values ranging from 13.91 to 111.72 µM. In the case of M059J, AA exhibited selective cytotoxicity after 48 h of treatment (IC50 = 24 µM), decreasing the percentage of cells in the G0/G1 phase, increasing the percentage of cells in the S phase, and inducing apoptosis. A significant increase in chromosomal damage was observed in V79 cell cultures treated with AA (40 µM), revealing genotoxic activity. In contrast, low concentrations (5, 10, and 20 µM) of AA significantly reduced the frequencies of micronuclei induced by the mutagens doxorubicin (DXR), methyl methanesulfonate, and hydrogen peroxide. A reduction of DXR-induced intracellular free radicals was found in V79 cells treated with AA (10 µM). The antigenotoxic effect of AA (30 mg/kg) was also observed against DXR-induced chromosomal damage in Swiss mice. Significant reductions in p53 levels were verified in the liver tissue of these animals. Taken together, the data indicate that AA exerted antiproliferative activity in M059J tumor cells, which is probably related to the induction of DNA damage, leading to cell cycle arrest and apoptosis. Additionally, low concentrations of AA exhibited antigenotoxic effects and its antioxidant activity may be responsible, at least in part, for chemoprevention.

Anti-Melanoma Activity of Indomethacin Incorporated into Mesoporous Silica Nanoparticles.

Melanoma is the deadliest type of skin cancer. Treatments that directly address tumor survival are required. Indomethacin (IND) is a well-known drug used worldwide. Although widely used as a therapeutic agent, IND has undesirable gastrointestinal effects. PURPOSE: To investigate the antitumor efficacy of IND incorporated into mesoporous silica nanoparticles (MSNPs+IND), as well as its toxic potential in a syngeneic murine B16 melanoma model. METHODS: Antitumor activity was evaluated by measuring tumor size and weight and by histopathological analysis. Possible molecular signaling pathways involved in the antitumor activity were analyzed by Western blot in liver tissue and by immunohistochemistry in tumor tissue. The potential toxicity was evaluated by determining body and organ weights and by biochemical and genotoxic analysis. RESULTS: MSNPs+IND treatments inhibited tumor growth by up to 70.09% and decreased the frequency of mitosis in tumor tissues, which was up to 37.95% lower compared to the IND groups. In hepatic tissue, COX-2 levels decreased significantly after treatment with MSNPs+IND and IND. Additionally, MSNPs+IND and IND increased the levels of cleaved caspase-3 (156.25% and 137.50%, respectively), inducing tumor cell apoptosis. Genotoxicity was limited to the group treated with the higher concentration of IND, while MSNPs prevented IND-induced genotoxicity. CONCLUSIONS: MSNPs may be promising for future applications in cancer therapy.

Betulinic acid modulates urethane-induced genotoxicity and mutagenicity in mice and Drosophila melanogaster.

Betulinic acid (BA) is a pentacyclic triterpenoid found in several plant species. Urethane (URE) is a known promutagen. Here, we examine the genotoxicity and mutagenicity of BA alone or in combination with URE using the bone marrow micronucleus assay in mice bone marrow cells and the Somatic Mutation and Recombination Test in Drosophila melanogaster. Findings revealed that BA alone was not genotoxic, but reduced the frequency of micronucleus when compared to the positive control. No significant differences were observed in the cytotoxicity. Biochemical analyzes showed no significant differences for liver (AST and ALT) or renal (creatinine and urea) function parameters, indicating the absence of hepatotoxic and nephrotoxic effects. BA alone did not increase the frequency of mutant spots, but reduced the total frequency of mutant spots when co-administered with URE in both ST and HB crosses. In addition, BA reduced the recombinogenic effect of URE at the highest concentrations of both crosses. In conclusion, under experimental conditions, BA has modulatory effects on the genotoxicity induced by URE in mice, as well as in somatic cells of D. melanogaster. We suggest that the modulatory effects of BA may be mainly due to its antioxidant and apoptotic properties.

Usnic acid attenuates genomic instability in Chinese hamster ovary (CHO) cells as well as chemical-induced preneoplastic lesions in rat colon.

Usnic acid (UA) is one of the pharmacologically most important compounds produced by several lichen species. To better understand the mechanism of action (MOA) of this important substance, this study examined the genotoxicity attributed to UA and its influence on mutagens with varying MOA using the micronucleus (MN) test in Chinese hamster ovary cells (CHO). Additional experiments were conducted to investigate the effect of UA on colon carcinogenesis in Wistar rats employing the aberrant crypt focus (ACF) assay. In vitro studies showed a significant increase in the frequency of MN in cultures treated with the highest UA concentration tested (87.13 µM). In contrast, UA concentrations of 10.89, 21.78, or 43.56 µM produced an approximate 60% reduction in chromosomal damage induced by doxorubicin, hydrogen peroxide, and etoposide, indicating an antigenotoxic effect. In the ACF assay, male Wistar rats treated with different UA doses (3.125, 12.5, or 50 mg/kg b.w.) and with the carcinogen 1,2-dimethylhydrazine exhibited a significantly lower incidence of neoplastic lesions in the colon than animals treated only with the carcinogen. Data suggest that the MOA responsible for the chemopreventive effect of UA may be related to interaction with DNA topoisomerase II and/or the antioxidant potential of the compound.

Chemopreventive role of Copaifera reticulata Ducke oleoresin in colon carcinogenesis.

In Brazilian folk medicine, copaiba oleoresin is widely known for its therapeutic activity, especially its wound healing and anti-inflammatory actions. Considering the relationship between inflammatory processes and carcinogenesis, this paper reports on the Copaifera reticulata Ducke oleoresin (CRO) chemopreventive potential in the colon carcinogenesis model in rats. To understand the mechanisms involved in this effect, the anti-inflammatory activity of CRO and its major chemical constituent, the diterpene ent-polyalthic acid (PA), were evaluated on the production of nitric oxide (NO) and prostaglandin E2 (PGE2) in mouse macrophages. For the chemoprevention assessment, the effect of CRO administered by gavage was investigated on DNA damage, pre-neoplastic lesions and mitotic frequencies induced by the 1,2-dimethylhydrazine (DMH; intraperitoneal injection) carcinogen by comet, aberrant crypt focus (ACF) and long-term assays, respectively. CRO reduced DNA damage (average 31.5%) and pre-neoplastic lesions (average 64.5%) induced by DMH, which revealed that CRO has antigenotoxic and anticarcinogenic effects. In the long-term assay, treatment with CRO significantly decreased mitoses in the tumor tissue, which suggested that CRO influenced carcinogenesis progression. PA reduced NO levels induced by lipopolysaccharides in macrophages. However, this diterpene showed no effect on PGE2. Taken together, our results suggest that PA exerts anti-inflammatory action via the NO pathway. The CRO chemopreventive effect may be partly due to the anti-inflammatory property of its major chemical constituent, PA. Our findings indicate that CRO is a promising agent to suppress colon carcinogenesis.