ABSTRACT
Objective: To explore the anti-proliferative activity of purified L-asparaginase from Aspergillus oryzae CCT 3940 (A. oryzae). Methods: L-asparaginase was produced by submerged fermentation and purified to electrophoresis homogeneity by ionic exchanged chromatography in a fast protein liquid chromatographic system. The purified enzyme was characterized and used for the anti-proliferative assay against nine tumor cell lines and one non-tumor cell line. Results: The free glutaminase L-asparaginase was purified 28.6 fold. L-asparaginase showed high stability under physiological condition, remaining stable in the pH range 7.0–8.0 after 1 h incubation at temperature range 30–45 °C. The Km and Vmax values of purified L-asparaginase were estimated as 0.66 mmol/L and 313 IU/mL, respectively. The purified enzyme could inhibit the growth of a broad range of human tumor cell lines at the concentrations studied. Also, the enzyme from A. oryzae CCT 3940 could inhibit tumor growth of leukemia cell line (K562) with a total growth inhibition value of (3.2 ± 2.5) IU/mL and did not inhibit the non-carcinogenic human cell line growth at the concentrations studied. Conclusions: The sensitivity of the cells lines to purified L-asparaginase from A. oryzae CCT 3940 appeared to be concentration dependent affording a more significant decrease in cell growth than that observed for the commercial L-asparaginase from Escherichia coli. The L-asparaginase from A. oryzae CCT 3940 has a high potential for pharmaceu-tical exploitation in the treatment of leukemia.
ABSTRACT
Objective To explore the anti-proliferative activity of purified L-asparaginase from Aspergillus oryzae CCT 3940 (A. oryzae). Methods L-asparaginase was produced by submerged fermentation and purified to electrophoresis homogeneity by ionic exchanged chromatography in a fast protein liquid chromatographic system. The purified enzyme was characterized and used for the antiproliferative assay against nine tumor cell lines and one non-tumor cell line. Results The free glutaminase L-asparaginase was purified 28.6 fold. L-asparaginase showed high stability under physiological condition, remaining stable in the pH range 7.0–8.0 after 1 h incubation at temperature range 30–45 °C. The Km and Vmax values of purified L-asparaginase were estimated as 0.66 mmol/L and 313 IU/mL, respectively. The purified enzyme could inhibit the growth of a broad range of human tumor cell lines at the concentrations studied. Also, the enzyme from A. oryzae CCT 3940 could inhibit tumor growth of leukemia cell line (K562) with a total growth inhibition value of (3.2 ± 2.5) IU/mL and did not inhibit the non-carcinogenic human cell line growth at the concentrations studied. Conclusions The sensitivity of the cells lines to purified L-asparaginase from A. oryzae CCT 3940 appeared to be concentration dependent affording a more significant decrease in cell growth than that observed for the commercial L-asparaginase from Escherichia coli. The L-asparaginase from A. oryzae CCT 3940 has a high potential for pharmaceutical exploitation in the treatment of leukemia.
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Objective To develop paclitaxel-loaded polymeric micelles from poly (ε-caprolactone)-poly (ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL),and to evaluate in vitro cytotoxicity as well as in vivo antitumor activity against EMT-6 tumor breast cell.Methods Paclitaxel-loaded polymeric micelles were prepared by thin-film hydration and ultrasonic method.The physical status of paclitaxel inside the polymeric micelles was investigated by differential scanning calorimetry (DSC).In vitro cytotoxicity of paclitaxel-loaded polymeric micelles against EMT-6 cell line was assessed by MTT assay.In vivo anticancer activity was evaluated against EMT-6 tumorbearing mice,with commercially available Taxol injection as control.Results Paclitaxel-loaded polymeric micelles exhibited homogeneous spherical shapes with apparent core-shell morphology.The average diameter of paclitaxelloaded polymeric micelles was 93 nm.DSC study indicated that paclitaxel was in solid amorphous state after being encapsulated in the polymeric micelles.In vitro cytotoxicity demonstrated that the cytotoxic effect of paclitaxelloaded polymeric micelles was lower than that of Taxol injection at the same paclitaxel content.Paclitaxel-loaded polymeric micelles showed greater tumor growth-inhibition effect in vivo on EMT-6 breast tumor in comparison with that of Taxol injection,with tumor growth inhibition of 85.79％ and 63.37％,respectively (P＜0.05).Conculsions The prepared paclitaxel-loaded polymeric micelles showed high anti-tumoral efficacy and low toxicity,and might have the potential to be developed as an effective anticancer drug-delivery system for cancer chemotherapy.
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Bioassay guided isolation of active natural compounds was performed to investigate the anti-tumor potential of the crude extract and isolated compounds from inflorescences of Piper claussenianum. LC-DAD-UV, GC-MS and NMR analyzes revealed the presence of phenolic metabolites in the methanol crude extract. Phytochemical procedures lead to the isolation of the major flavonoids, 2’,6’-dihydroxy-4-methoxychalcone, 5,7- dihydroxyflavanone and 5-methoxy-7-hydroxyflavanone that were assayed for inhibition or viability stimulation of the human breast cancer cell line MCF-7. The results suggest the 2’,6’-dihydroxy-4-methoxychalcone as the biologically active compound in the crude methanol extract of inflorescences from P. claussenianum. The crude extract was found as potential natural source of compounds with breast cancer cell inhibition properties. All isolated compounds have not been described from this species yet.
ABSTRACT
We analyzed the in vitro effects of the anti-tumoral drugs doxorubicin, cytosine arabinoside and hydroxyurea on the G2-prophase checkpoint in lymphocytes from healthy individuals. At biologically equivalent concentrations, the induced DNA damage activated the corresponding checkpoint. Thus: i) there was a concentration-dependent delay of G2 time and an increase of both the total DNA lesions produced and repaired before metaphase and; ii) G2-checkpoint adaptation took place as chromosome aberrations (CAs) started to appear in the metaphase, indicating the presence of unrepaired double-strand breaks (DSBs) in the previous G2. The checkpoint ATM/ATR kinases are involved in DSB repair, since the recorded frequency of CAs increased when both kinases were caffeine-abrogated. In genotoxic-treated cells about three-fold higher repair activity was observed in relation to the endogenous background level of DNA lesions. The maximum rate of DNA repaired was 3.4 CAs/100 metaphases/hour, this rise being accompanied by a modest 1.3 fold lengthening of late G2 prophase timing. Because of mitotic chromosome condensation, no DSBs repair can take place until the G1 phase of the next cell cycle, when it occurs by DNA non-homologous end joining (NHEJ). Chromosomal rearrangements formed as a consequence of these error-prone DSB repairs ensure the development of genome instability through the DNA-fusion-bridge cycle. Hence, adaptation of the G2 checkpoint supports the appearance of secondary neoplasia in patients pretreated with genotoxic drugs.
Subject(s)
Adult , Female , Humans , Male , Young Adult , Antibiotics, Antineoplastic/toxicity , Chromosome Aberrations/chemically induced , /drug effects , Lymphocytes/drug effects , Prophase/drug effects , Cytarabine/toxicity , DNA Damage/drug effects , Doxorubicin/toxicity , /genetics , Hydroxyurea/toxicity , Lymphocytes/cytologyABSTRACT
Allamanda (Apocynaceae) is a genus of climbing shrubs known for producing compounds with a range of biological activities. Previous works have shown the anti-proliferative effect of the ethanolic extract of Allamanda schottii on leukemic cells. The present work was conducted to evaluate the effects of dichloromethane fraction, obtained from Allamanda schottii, on sea urchin Echinometra lucunter eggs, as a multicellular model for evaluating anti-tumor activity. Our results show an inhibition of sea urchin development in a dose-dependent manner in the presence of dichloromethane fraction. The IC50 values for first and third cleavage and blastulae stage were 103.7 µg/mL, 33.1 µg/mL and 10.2 µg/mL, respectively. These results also demonstrate the cumulative effect of this fraction on sea urchin embryos. In the present work, the expressive anti-mitotic activity of dichloromethane fraction towards sea urchin eggs, a multicellular model, reinforces the anti-tumor potential of the Allamanda schotti.
Allamanda (Apocynacea) é um gênero de arbustos escandentes conhecido por produzir compostos com várias atividades biológicas. Trabalhos anteriores têm mostrado um efeito anti-proliferativo do extrato etanólico de Allamanda schottii sobre células leucêmicas. O presente trabalho foi realizado para avaliar o efeito da fração diclorometano, obtida de Allamanda schotti, sobre os ovos de ouriço-do-mar de Echinometra lucunter, como um modelo multicelular para estudar atividade anti-tumoral. Nossos resultados mostram uma inibição do desenvolvimento dos ovos de uma maneira dose-dependente na presença da fração diclorometano. Os valores de IC50 para a primeira e terceira clivagem e para o estágio de blástula foram de 103,7 µg/mL, 33.1 µg/mL e 10,2 µg/mL, respectivamente. Estes resultados também demonstram um efeito acumulativo da fração sobre os embriões do ouriço-do-mar. No presente trabalho, esta expressiva atividade anti-mitótica da fração diclorometano sobre o desenvolvimento embrionário do ouriço-do-mar, um modelo multicelular, reforça o potencial antitumoral de Allamanda schotti.