A study on inhibition mechanism of breast cancer cells by bis-type triaziquone

Nanocurcumin: preparation, characterization and cytotoxic effects towards human laryngeal cancer cells

The aim of the present study was to prepare curcumin nanoparticles (nanocurcumin) by a sol-oil method to improve curcumin absorption and bioavailability, and to investigate the therapeutic effects of the prepared nanoparticles on the inhibition mechanisms towards human Hep-2 cancer cells. The nanoparticles were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, and zeta potential analysis. The prepared curcumin nanoparticles possessed a narrow particle size distribution with an average diameter of 28 nm. The inhibition effects on the growth of human Hep-2 cells were investigated using neutral red uptake and lactate dehydrogenase assays. The results indicated that the nanocurcumin has a selective effect in inhibiting Hep-2 cell growth in a dose- and time-dependent mode with the most effective IC₅₀ value (17 ± 0.31 μg ml⁻¹) obtained after 48 h of incubation without any cytotoxic effects on normal cells. This IC₅₀ value of nanocurcumin revealed a significant increase of early and late apoptotic cells with an intense comet nucleus of Hep-2 cells as a marker of DNA damage. Flow cytometry analysis of the progression of apoptosis in nanocurcumin Hep-2 treated cells showed that arresting in the cell cycle in the G2/M phase with increasing apoptotic cells in the sub-G1 phase. At the same time, real-time PCR analysis indicated that the treatment of Hep-2 cells with nanocurcumin resulted in upregulation of P53, Bax, and Caspase-3, whereas there was downregulation of Bcl-XL. These findings gave insights into understanding that the inhibition mechanisms of nanocurcumin on the proliferation of Hep-2 cancer cells was through the G2/M cell cycle arrest and the induction of apoptosis was dependent on Caspase-3 and p53 activation. However, in vivo studies with an animal model are essential to validate these results.

The aim of this study was to prepare curcumin nanoparticles using a sol–oil method to improve curcumin absorption and bioavailability, and to investigate the therapeutic effect of the prepared nanoparticles on the inhibition mechanisms toward human Hep-2 cancer cells.

Inhibition of lung cancer cells A549 and H460 by curcuminoid extracts and nanoemulsions prepared from Curcuma longa Linnaeus

The objectives of this study were to explore the inhibition mechanism of lung cancer cells A549 and H460 by curcuminoid extracts and nanoemulsions prepared from Curcuma longa Linnaeus. In addition, human bronchus epithelial cell line BEAS-2B (normal cell) was selected for comparison. A high-performance liquid chromatography (HPLC) method was developed to separate and quantify the various curcuminoids in C. longa extract, including curcumin (1,714.5 μg/mL), demethoxycurcumin (1,147.4 μg/mL), and bisdemethoxycurcumin (190.2 μg/mL). A high-stability nanoemulsion composed of Tween 80, water, and curcuminoid extract was prepared, with mean particle size being 12.6 nm. The cell cycle was retarded at G2/M for both the curcuminoid extract and nanoemulsion treatments; however, the inhibition pathway may be different. H460 cells were more susceptible to apoptosis than A549 cells for both curcuminoid extract and nanoemulsion treatments. Growth of BEAS-2B remained unaffected for both the curcuminoid extract and nanoemulsion treatments, with a concentration range from 1 to 4 μg/mL. Also, the activities of caspase-3, caspase-8, and caspase-9 followed a dose-dependent increase for both A549 and H460 cells for both the treatments, accompanied by a dose-dependent increase in cytochrome C expression and a dose-dependent decrease in CDK1 expression. Interestingly, a dose-dependent increase in cyclin B expression was shown for A549 cells for both the treatments, while a reversed trend was found for H460 cells. Both mitochondria and death receptor pathways may be responsible for apoptosis of both A549 and H460 cells.

Antiproliferation of melanoma cells by polysaccharide isolated from Zizyphus jujuba

OBJECTIVE

Zizyphus jujuba, a traditional Chinese herb rich in functional components such as polysaccharide, has been widely consumed in Asian countries. The objective of this study was to determine the antiproliferation effect of melanoma cells as affected by deproteinized polysaccharide (DPP) isolated from Z. jujuba.

METHODS

Deproteinized polysaccharide was obtained through boiling water extraction, ethanol precipitation, deproteinization, and dialysis, and the molecular weight of DPP was determined by high-performance gel-filtration chromatography. Melanoma cell viability was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, the cell cycle was analyzed by flow cytometry, the formation of apoptotic bodies was observed under a fluorescence microscope at 450 nm, and caspase-3 and caspase-9 were measured by an assay kit.

RESULTS

Deproteinized polysaccharide was composed of two fractions with average molecular weights of 143 108 and 67 633 Da. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test showed that the antiproliferation effect of DPP on melanoma cells followed a dose- and time-dependent course. The 50% inhibitory concentration of DPP in inhibiting melanoma cell growth was 3.99 ± 0.10 mg/mL after 24-h treatment but decreased significantly to 3.36 ± 0.14 mg/mL after 48 h. The cell cycle assay revealed melanoma cells to be arrested in G2/M phase. Moreover, with DPP treatment, the apoptotic bodies were generated, accompanied by an increase in caspase-3 and caspase-9 activity.

CONCLUSIONS

This outcome suggested that DPP may be used as a potential anti-skin cancer agent for further in vivo and clinical trial experiments.