Antiproliferative and Genotoxic Action of an Underexploited Organoteluran Derivative on Sarcoma 180 Cells

BACKGROUND

The search for novel metallic chemical compounds with toxicogenic effects has been of great importance for more efficient cancer treatment.

OBJECTIVE

The study evaluated the cytotoxic, genotoxic and mutagenic activity of organoteluran RF07 in the S-180 cell line.

METHODS

The bioassays used were cell viability with 3-(4,5-dimethyl-2-thiazole)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test, evaluation of apoptosis and necrosis using fluorescence and flow cytometry, cytokinesisblock micronucleus test and comet assay. The compound was tested at 1; 2.5 and 5μM.

RESULTS

The results showed the cytotoxicity of RF07 at concentrations of 2.5, 5, 10 and 20μM when compared to the negative control. For genotoxicity tests, RF07 showed effects in all concentrations assessed by increased index and frequencies of damage and mutagenic alterations. The compound was also cytotoxic due to the significant decrease in the nuclear division index, with significant values of apoptosis and necrosis. The results of fluorescence and flow cytometry showed apoptosis as the main type of cell death caused by RF07 at 5μM, which is thought to avoid an aggressive immune response of the organism.

CONCLUSION

In addition to cytotoxic and genotoxic effects, RF07 creates good perspectives for future antitumor formulations.

Alpha-Terpineol as Antitumor Candidate in Pre-Clinical Studies

BACKGROUND

Alpha-terpineol is a monoterpene alcohol with anti-tumor activity against different tumor cell lines (lung, breast, leukemias and colorectal) through blockage of NF-kB expression, which play an important role in tumor cells growth.

OBJECTIVE

Evaluate the antitumor activity of alpha-terpineol in murine Sarcoma 180 cell line Methods: For the tests, different cytotoxic and genotoxic assays were used, including Trypan blue, cytokinesis-blocked micronucleus assay, comet assay, agarose gel DNA fragmentation, flow cytometry and cell viability using fluorescence. Ascitic fluid cells from sarcoma 180 were obtained from Mus musculus peritoneal cavity and Alpha-terpineol was tested at 100, 250 and 500 μg/mL. Doxorubicin and Cisplatin were used as positive controls.

RESULTS

Cytotoxic effects of alpha-terpineol were found in all concentrations tested, reducing cell viability in 50.9; 38.53; 30.82% at 100, 250 and 500 μg/mL, respectively. Alpha-terpineol induced genotoxic effects due to DNA fragmentation (increased frequency and index of damage), and was clastogenic by increased micronuclei formation, nucleoplasmic bridges and nuclear buds. DNA fragmentation and increased cell death indicated that alpha-terpineol can cause early, late, and necrotic apoptosis.

CONCLUSION

Our data indicate that alpha-terpineol has antitumor activity revealed by cytogenetic mechanisms and / or loss of cell membrane integrity.

Antiproliferative and photoprotective activities of the extracts and compounds from Calea fruticosa

In this paper, we complement our previous study on the antiproliferative activity of Calea fruticosa (Asteraceae) by isolating the compounds apigenin-4',7-dimethyl ether (1), budlein A (2), quercetin (3), and cichoriin (4) from the plant’s aerial parts. The antiproliferative activity of these compounds was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method against human tumor cell lines. Compound 3 displayed moderate antiproliferative activity in three cell lines (HCT-116, PC-3, and SF-295, with cell growth inhibition values of 72.97, 74.55, and 68.94%) and high antiproliferative activity (90.86%) in the HL-60 cell line. The in vitro sun protection factor (SPF) of the extracts and compound 4, with and without sunscreen, was determined by a spectrophotometric method. The ethanol extract exhibited the highest SPF (9.67) at a concentration of 0.100 mg/mL, while compound 4, isolated from this extract, showed a SPF of 13.79 at the same concentration. A relative increased efficacy of SPF was observed for the extracts and compound 4 when sunscreen was also used. Compound 4 has not been reported previously from any species within the genus Calea. Compounds 1–4 were obtained from this species for the first time.

Are salty liquid food flavorings in vitro antitumor substances?

The objective of this study was to evaluate the antiproliferative, cytotoxic and genotoxic potential of salty liquid synthetic flavorings of Butter, Cheddar Cheese and Onion. The antiproliferative potential (2.9-1500 µg/mL) was assessed by MTT assay after 72h using the human tumor lines SF-295 (glioblastoma), OVCAR-8 (ovarian), HCT-116 (colon) and HL-60 (promyelocytic leukemia) and primary cultures of murine Sarcoma 180 (S180) and peripheral blood mononuclear cells (PBMC). Allium cepa bulbs were exposed to growing respective doses (1 mL and 2 mL). Only Butter and Cheddar flavorings revealed cytotoxic activity on cancer cells, with IC50 values ranging from 125.4 µg/mL (Cheddar - HCT-116) to 402.6 µg/mL (Butter - OVCAR-8). Butter flavoring was the most cytotoxic on PBMC (136.3 µg/mL) and increased cell division rate in relation to the mitotic index but did not cause cellular aberrations. Onion and Cheddar flavorings reduced the mitotic index after 24h and 48h exposure, but only Onion flavoring resulted in cellular aberrations and mitotic spindle abnormalities, such as anaphase and telophase bridges, micronucleated cells, conchicine-metaphases and amplifications. So, Butter, Onion and/or Cheddar flavorings caused significant changes in the division of meristematic cells of A. cepa and presented cytotoxic action even on decontrolled proliferating human tumor cells.

Genotoxic and Mutagenic Activity of PT-31

Toxicity assessment is an important tool in drug discovery and development. PT-31 (3-(2-chloro-6-fluorobenzyl)-imidazolidine-2,4-dione) is an imidazolidine- 2,4-dione analogue of clonidine that displays a dose-dependent analgesic profile and synergism with morphine. This study investigated genotoxic and mutagenic effects of PT-31 in Swiss mice. For this, ten mice (M1:F1) per group were treated with PT-31 intraperitoneally (i.p.) at 0.5, 1.0 and 5.0 mg/kg. The dimethyl sulfoxide (0.5%) and 50 mg/kg cyclophosphamide (i.p.) were taken as negative (NC) and positive controls, respectively. The bone marrow cells were collected after 24 h, while peripheral blood after 30 min, 12 h and 24 h of the treatment for the comet assay. Micronucleus (MN) test was performed only on bone marrow cells collected after 24 h of i.p. treated animals. A hundred cells were considered for the comet assay and quantification of the index of damage and frequency of damage. Lack of genotoxicity with 0.5 mg/kg of PT-31 and DNA repair ability with 0.5 and 1.0 mg/kg doses at 12 h and 24 h in comparison to NC group was observed (P<0.05). There was an increase in MN formation by PT-31 1.0 and 5.0 mg/kg treated female and male mice, respectively. PT-31 induced genotoxic and mutagenic effects only in higher doses.

Cytotoxic clerodane diterpenes from Casearia rupestris

Four new clerodane diterpenes, casearupestrins A-D (1-4), were isolated from the leaves of Casearia rupestris. Compounds 1 and 4 were acetylated to yield 2,7-di-O-acetylcasearupestrin A (5) and 2,6-di-O-acetylcasearupestrin D (6). All compounds were evaluated for cytotoxicity against a small panel of human cancer cell lines. Casearupestrin A (1) exhibited the most potent activity against MDA/MB-435 (human melanoma) and SF-295 (human glioblastoma) cells, superior to that of the standard drug doxorubicin.

Lipoic acid effects on lipid peroxidation level, superoxide dismutase activity and monoamines concentration in rat hippocampus

The purposes of the present work were to verify lipid peroxidation level, superoxide dismutase (SOD) activity and monoamines (dopamine (DA), norepinephrine (NE), serotonin (5-HT)), and their metabolites (3,4-hydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA)) contents in rat hippocampus after lipoic acid (LA) administration. Wistar rats were treated with 0.9% saline (i.p., control group) and LA (10, 20 or 30 mg/kg, i.p., LA10, LA20 and LA30 groups, respectively). After the treatments all groups were observed for 24h. In LA20 group only there was a significant decrease in lipid peroxidation level. However, no alteration was observed in SOD activity in groups treated with LA. The NE and DA levels were increased only in 20mg/kg dose of LA in rat hippocampus. Serotonin content and their metabolite 5-HIAA levels was decreased in same dose of LA. On the other hand, DOPAC and HVA levels did not show any significant change. The reduction in lipid peroxidation level and alterations in hippocampal monoamines can be suggested as a possible brain mechanism from this antioxidant. The outcome of the study may have therapeutic implications in the neurodegenerative diseases.