ABSTRACT
<p><b>BACKGROUND</b>The suillin isoform iso-suillin is a natural substance isolated from a petroleum ether extract of the fruiting bodies of the mushroom Suillus flavus. Previous studies have found its inhibition effect on some cancer cells, and we aimed to study its effects on human small cell lung cancer H446 cell line.</p><p><b>METHODS</b>Cell viability was measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay. Cellular morphological changes (apoptosis and necrosis) were evaluated using an electron microscope and Hoechst 33258 staining detected by the inverted microscope. Flow cytometry was used to detect cell apoptosis, cell cycle distribution, and mitochondrial membrane potential. Protein expression was determined by Western blotting analysis.</p><p><b>RESULTS</b>Here, we describe the ability of iso-suillin to inhibit the growth of H446 cells in time- and dose-dependent way. Iso-suillin had no obvious impact on normal human lymphocyte proliferation at low concentrations (9.09, 18.17, or 36.35 μmol/L) but promoted lymphocyte proliferation at a high concentration (72.70 μmol/L). After treatment of different concentrations of iso-suillin (6.82, 13.63, or 20.45 μmol/L), the apoptosis rate of H446 cells increased with increasing concentrations of iso-suillin (16.70%, 35.54%, and 49.20%, respectively, all P < 0.05 compared with the control), and the expression of related apoptotic proteins in the mitochondrial pathway including cytochrome c and caspase-9 were up-regulated compared with the control (all P < 0.05). On the contrary, Bcl-2/Bax ratio was down-regulated compared with the control. Besides, the expression of pro-apoptotic proteins in the death receptor apoptosis pathway, including Fas-associating protein with a novel death domain and caspase-8, and the expression of caspase-3, a downstream regulatory protein of apoptosis, were also increased compared with the control (all P < 0.05). Inhibitors of caspase-9 and caspase-8 reversed the apoptosis process in H446 cells to varying degrees.</p><p><b>CONCLUSIONS</b>These results suggest that iso-suillin could induce H446 cell apoptosis through the mitochondrial pathway and the death-receptor pathway. Therefore, iso-suillin might have a potential application as a novel drug for lung cancer treatment.</p>
Subject(s)
Animals , Humans , Mice , Apoptosis , Caspase 3 , Metabolism , Caspase 8 , Metabolism , Caspase 9 , Metabolism , Cell Line, Tumor , Cell Survival , Cytochromes c , Metabolism , Diterpenes , Pharmacology , Flow Cytometry , Phenols , Pharmacology , Small Cell Lung CarcinomaABSTRACT
Objective: To optimize the formulations of microporosity osmotic pump controlled release tablet of solid dispersion for total flavonoids from Desmodium styracifolium (TFDS) by central composite design-response surface methodology. Methods: The independent variables comprised of the amount of lactose, pore-forming agent, and coating weight gain, and the dependent variables involved the cumulative release after 2, 6, and 12 h, and the linear correlation coefficient of cumulative release curve. Design-expert software was used to fit multivariate linear models and quadratic multinomial models for experimental data. Response surface was delineated according to best-fit mathematic models and the optimum formulation was selected by Numerical Optimization. Results: The correlation coefficients of quadratic multinomial models were better than those of multivariate linear models. There was close agreement between the observed and predicted values for the cumulative release, and bias were all less than 5%. Conclusion: The model established by Design-expert Software is better to predict and could be used to optimize the formulations of microporosity osmotic pump controlled release tablets of solid dispersion for TFDS.
ABSTRACT
<p><b>BACKGROUND</b>Small cell lung cancer (SCLC) is the most aggressive form of lung cancer. This study aimed to investigate the mechanism of human small cell lung cancer cell line resistance to etoposide (VP-16), H446/VP.</p><p><b>METHODS</b>The cell viability was measured by MTT assay. Immunocytochemistry, reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting methods were used to detect the multidrug resistance gene (MDR1), bcl-2, bax and the topoisomerase II (Topo II) expressions in H446 and H446/VP cells after treated with or without VP-16.</p><p><b>RESULTS</b>The 50% inhibition concentration (IC50) of VP-16 on H446 cells was 49 mg/L, and 836 mg/L was for H446/VP cells. The expressions of MDR1 and bcl-2 were up-regulated, while the amounts of bax and Topo II were reduced in H446/VP cells. After treated with 49 mg/L of VP-16, it showed that the drug could significantly inhibit bcl-2 and Topo II expressions, and increase bax expression in H446 cells compared with that of H446/VP cells.</p><p><b>CONCLUSIONS</b>The H446/VP cell was stably resistant to VP-16. The decreased expression of Topo II was correlated with the H446/VP multidrug resistance. The elevated expressions of MDR1, and the altered apoptotic pathways also played an important role in VP-16 induced multidrug resistance of SCLC.</p>