Targeting ROS overgeneration by N-benzyl-2-nitro-1-imidazole-acetamide as a potential therapeutic reposition approach for cancer therapy.

BackgroundWe investigated the role of reactive oxygen species (ROS) in the anticancer mechanism of N-benzyl-2-nitro-1-imidazole-acetamide (BZN), a drug used in Chagas' disease treatment. MethodsBALB/c mice, inoculated with Ehrlich ascites carcinoma (EAC), were treated with BZN or BZN + Nacylcysteine (NAC) or NAC for 9 days. Subsequently, the inhibition of tumor growth and angiogenesis as well as animal survival were evaluated. Apoptosis and the cell cycle were evaluated using fluorescence microscopy and flow cytometry, while oxidative stress was evaluated by measuring TBARS content, DNA damage, calcium influx and ROS generation and antioxidant defenses (CAT, SOD, GPx, GST and GR). Immunoblotting was used to evaluate key death and cell cycle proteins. Results BZN treatment inhibited tumor progression (79%), angiogenesis (2.8-fold) and increased animal survival (29%). Moreover, BZN increased ROS levels (42%), calcium influx (55%), TBARS contents (1.9-fold), SOD (4.4-fold), GPx (17.5-fold) and GST (3-fold) activities and GSH depletion (2.5-fold) also caused DNA fragmentation (7.6-fold), increased cleaved PARP and promoted the trapping of cells in the G1 phase, as corroborated by the reduction in cyclin A and increased CDK2 protein levels. In silico DNA and molecular dynamic simulations showed H-bonds and hydrophobic interactions that were confirmed by circular dichroism. Increased apoptosis (232%), induced by treatment with BZN, was demonstrated by apoptotic cell staining and p53 level. Conclusion The current findings indicate that BZN acts as a tumor growth inhibitor and anti-angiogenic agent by ROS overgeneration, which interact with DNA causing damage and triggering apoptosis.

Novel selenylated imidazo[1,2-a]pyridines for breast cancer chemotherapy: Inhibition of cell proliferation by Akt-mediated regulation, DNA cleavage and apoptosis.

A novel series of selenylated imidazo[1,2-a]pyridines were designed and synthesized with a view to a promising activity against breast cancer cell. The compounds, 7-methyl-3-(naphthalene-1-ylselanyl)-2-phenylimidazo[1,2-a]pyridine, named IP-Se-05, and 3-((2-methoxyphenyl)selanyl)-7-methyl-2-phenylimidazo[1,2-a]pyridine, named IP-Se-06, showed high cytotoxicity for MCF-7 cells (IC50 = 26.0 µM and 12.5 µM, respectively). Both the compounds inhibited the cell proliferation and caused decrease in the number of cells in the G2/M phase of cell cycle. IP-Se-05 and IP-Se-06 were also evaluated for effects on CT-DNA and DNA of MCF-7 cells. The compounds intercalated into CT-DNA and both treatments caused cleavage of DNA in cells. In addition, the compounds induced cell death by apoptosis. However, the presence of (2-methoxyphenyl) selenyl moiety at the imidazo[1,2-a]pyridine (IP-Se-06) appears to have a better antitumor effect with higher cytotoxicity at a lower concentration and caused less necrosis. Overall, the current study established IP-Se-06 more than IP-Se-05 as a potential prototype compound to be employed as an antiproliferative agent for the treatment of breast cancer.

CDK2 and Bcl-xL inhibitory mechanisms by docking simulations and anti-tumor activity from piperine enriched supercritical extract.

Supercritical fluid technologies offer an innovative method for food industry and drug discovery from natural sources. The aim of the study is to investigate the anti-tumor activity of piperine rich extract by supercritical fluid (SFE) from black pepper (Piper nigrum). In silico docking simulations predicted anti-tumor molecular mechanism and protein-piperine hydrophobic interactions, showing hydrogen bonds between piperine and residue Ser5 inside the ATP binding site in CDK2. Moreover, piperine interacts with peptide substrate residue Lys8 inside its binding site in Cyclin A molecule. Other predicted interaction showed piperine inside the hydrophobic groove of Bcl-xL. Confirming the docking simulation, in vitro assays with SFE (40 °C/30 MPa) showed cytotoxicity to MCF-7 cells (IC50 = 27.8 ±â€¯6.8 µg/ml) correlated to increased apoptosis. Balb/c mice-bearing Ehrlich Ascites Carcinoma (EAC) group that received the SFE (100 mg/kg/day) showed tumor growth inhibition (60%) and increased mice survival (50%), probably related to cell cycle arrest (G2/M) and increased apoptosis. In vivo treatments with SFE increased the expression of pro-apoptotic proteins (p53 and Bax), inhibited cell cycle proteins (CDK2, Cyclin A) and anti-apoptotic protein (Bcl-xL). Thus, confirming in silico predicted inhibitory interactions. These results clearly showed promising performance of the piperine-rich fraction recovered from black pepper, drawing attention to its use as complementary therapy for cancer.

Novel pyrimidinic selenourea induces DNA damage, cell cycle arrest, and apoptosis in human breast carcinoma.

Novel pyrimidinic selenoureas were synthesized and evaluated against tumour and normal cell lines. Among these, the compound named 3j initially showed relevant cytotoxicity and selectivity for tumour cells. Three analogues of 3j were designed and synthesized keeping in view the structural requirements of this compound. Almost all the tested compounds displayed considerable cytotoxicity. However, 8a, one of the 3j analogues, was shown to be highly selective and cytotoxic, especially for breast carcinoma cells (MCF-7) (IC50 = 3.9 µM). Furthermore, 8a caused DNA damage, inhibited cell proliferation, was able to arrest cell cycle in S phase, and induced cell death by apoptosis in human breast carcinoma cells. Moreover, predictions of pharmacokinetic properties showed that 8a may present good absorption and permeation characteristics for oral administration. Overall, the current study established 8a as a potential drug prototype to be employed as a DNA interactive cytotoxic agent for the treatment of breast cancer.

In vivo antitumor activity of by-products of Passiflora edulis f. flavicarpa Deg. Rich in medium and long chain fatty acids evaluated through oxidative stress markers, cell cycle arrest and apoptosis induction.

Antiinflammatory and antitumor activity has been reported in Passiflora edulis (yellow passion fruit) nevertheless the intrinsic mechanisms of action are not fully elucidated. The present study aimeds to perform a comparison between the antitumor activity involving the crude extract (HCE) and the supercritical fluid extract with ethanol as co-solvent (SFEtOH) from P. edulis f. flavicarpa Deg. The in vitro cytotoxicity was evaluated in MCF-7 cells, while the in vivo antitumor activity was assessed in male Balb/c mice inoculated with Ehrlich carcinoma cells. SFEtOH exhibited higher antitumor activity compared to HCE. Wherein, SFEtOH showed an EC50 of 264.6 µg/mL against MCF-7 cells as well as an increased inhibition of tumor growth of 48.5% (p < 0.001) in male Balb/c mice, thereby promoting an increased mice lifespan to approximately 42%. Moreover, SFEtOH caused lipid (p < 0.001) and protein (p < 0.001) oxidation by increasing glutathione redox cycle activity while decreased the thioredoxin reductase activity (p < 0.001). SFEtOH also induced oxidative DNA damage in Ehrlich ascites carcinoma (EAC) cells leading to G2/M cycle arrest and has increased apoptotic cells up to 48.2%. These data suggest that the probable mechanisms of antitumor effect are associated to the lipid, protein and DNA damage, leading to cell cycle arrest and triggering apoptosis via mitochondrial pathway, should be probable due to the presence of medium and long chain fatty acids such as lauric acid.