Application of proteomics to identify the target molecules involved in Lonicera japonica-induced photokilling in human lung cancer CH27 cells.

BACKGROUND: The Lonicera japonica has been used as natural and healthy drink for its anti-inflammatory effect and pleasant odor in China and Taiwan. METHODS: 2D electrophoresis was used to analyze the proteins involved in photoactivated Lonicera japonica-induced CH27 cell apoptosis. The fluorescent dyes MitoTracker Red CMXRos, calcein AM and JC-1 were used to elucidate mitochondrial function. The protein expression was performed by Western blotting. Fluorescent image of endoplasmic reticulum was accomplished by using ER-Tracker Green. This study used fluorescent dye CM-H2DCFDA to detect intracellular generation of reactive oxygen species. RESULTS: The identified proteins can be classified into three major groups, which include proteins involved in mitochondrial function, cytoskeleton-related proteins and proteins associated with endoplasmic reticulum (ER) stress. Photoactivated Lonicera japonica caused a significant effect on the mitochondrial function and ER stress in CH27 cells. The reactive oxygen species producing was found to be involved in photoactivated Lonicera japonica-induced CH27 cell apoptosis. CONCLUSION: Mitochondria and endoplasmic reticulum are the integral targets in photoactivated Lonicera japonica-induced CH27 cell apoptosis. We also demonstrated that ethyl acetate fraction of Lonicera japonica extracts caused photocytotoxicity in a dose-dependent manner in CH27 cells. This could explain the fact that the ethyl acetate fraction of Lonicera japonica extracts may contain compounds which exhibit the photosensitizing activity in CH27 cells.

2-(Naphthalene-1-yl)-6-pyrrolidinyl-4-quinazolinone inhibits skin cancer M21 cell proliferation through aberrant expression of microtubules and the cell cycle.

Microtubules are a proven target for anticancer drug development because they are critical for mitotic spindle formation and the separation of chromosomes at mitosis. 2-(Naphthalene-1-yl)-6-pyrrolidinyl-4-quinazolinone (HL66) induced cell death with the large cells and multiple micronuclei in M21 skin cancer cells. We demonstrated that HL66-induced cell death is caspase-independent and accompanied by the failure of cell cycle progression. Therefore, HL66-induced cell death may be a mitotic catastrophe. HL66 inhibits the dephosphorylation on Thr14 or Tyr15 of cyclin-dependent kinase (Cdk) 1 and the formation of Cdk1/cyclin B1 complex, which might be associated with cell cycle arrest at the S and G(2)/M phases. HL66 is an antimicrotubule agent by molecular modeling on the basis of ligand binding to tubulin molecule. Furthermore, we also demonstrated that HL66, like vinblastine, is a tubulin-destabilizing agent via microtubule disruption in M21 cells. These results describe a novel pharmacological property of HL66 as a microtubule inhibitor, which may make it an attractive new agent for the treatment of skin cancer.

Up-regulation of matrix metalloproteinase family gene involvement in ursolic acid-induced human lung non-small carcinoma cell apoptosis.

Ursolic acid is a triterpenoid reported to inhibit the invasion of cancer cells. In this study, there was a significant increase in the gene expression of matrix metalloproteinase (MMP)-1, -2 -3, -9 and -10 in H460 cells after treatment with 10 microM ursolic acid for 24 h. Under these experimental conditions, it was found that ursolic acid induced H460 cell apoptosis. These results indicated that matrix metalloproteinase family members are involved not only in invasion, but also in apoptosis of cancer cells. It has been suggested that ursolic acid acts via a glucocorticoid receptor in the regulation of MMP. Our study also demonstrated that the localization of glucocorticoid receptor in the cytosol might be an important factor of MMP up-regulation during ursolic acid-induced H460 cell apoptosis. Ursolic acid induced a typical apoptosis on H460 cells, which was characterized by the activation of caspase-3, nuclear morphological changes and DNA fragmentation.

Baicalein induced cell cycle arrest and apoptosis in human lung squamous carcinoma CH27 cells.

Baicalein, a flavonoid compound, is one of the active constituents of the root of Scutellariae Radix. Baicalein inhibited the growth of human lung squamous carcinoma CH27 cells in a dose-dependent manner. Cell cycle analysis revealed an increase in the S-phase cell population following 24-h exposure to 50 microM baicalein. During the S-phase arrest, analysis of cell cycle regulatory molecules demonstrated that baicalein decreased the levels of cdk 4, cyclin B1 and cyclin D1. Furthermore, baicalein (50 microM) significantly induced cell apoptosis after 3 days of treatment. Baicalein induced apoptosis, as confirmed by condensed nuclei and DNA fragmentation, in CH27 cells. Baicalein-induced apoptosis was also accompanied by a decrease in Bcl-2 and caspase-3 proform levels. These results suggest that baicalein inhibits the proliferation of CH27 cells via S-phase arrest and apoptosis.