Anti-carcinogenic actions of glycoprotein conjugated with isoflavones from submerged-liquid culture of Agaricus blazei mycelia through reciprocal expression of Bcl-2 and Bax proteins / 동물의과학연구지

Glycoproteins isolated from fruit bodies and mycelial cultures of mushrooms exhibit anti-carcinogenic actions in human cancer cells and animal tumor cells by induction of apoptosis. Here, we report that isoflavone-conjugated glycoproteins (designate Gluvone), exhibit strong anti-carcinogenic effects on human breast cancer MCF-7 cells by induction of apoptosis. Gluvone with 9.4 kDa of molecular weight was isolated from submerged-liquid culture of Agaricus blazei mycelia (ABM) in soy flake-containing liquid medium. MCF-7 cells were incubated with various amounts of Gluvone (0~250 microM) for a period of 6 days. Gluvone exhibited anti-proliferative actions in a dose-dependent manner and 62% growth inhibition at 200 microM for 4 days relative to control. Hoechst 33258 staining analysis revealed that Gluvone induced formation of apoptotic bodies. Gluvone was associated with down-regulation of anti-apoptotic Bcl-2 protein expression as well as up-regulation of pro-apoptotic Bax protein expression. Gluvone treatment induced proteolytic activation of caspase-9 and caspase-3 through cytochrome c release from mitochondria to cytosol as well as concomitant degradation of poly (ADP-ribose) polymerase (PARP). In addition, Gluvone induced activation of caspase-8. Taken all together, these results indicate that the anti-proliferative effect of Gluvone is associated with induction of apoptotic cell death through the mitochondrial dysfunction pathway mediated by enhancement of Bax protein expression and suppression of Bcl-2 protein expression.

Anti-proliferative efficacy comparison of conjugated linoleic acid on human cancer cell lines / 동물의과학연구지

The anti-proliferative efficacy of t,t-conjugated linoleic acid (t,t-CLA), c9,t11-CLA, and t10,c12-CLA was compared in several human cancer cell lines. Gastric NCI-N87, liver Hep3B, pancreas Capan-2, and lung NCI-H522 cancer cells were incubated with 50 microM CLA isomers over a period of 6 days. The t,t-CLA inhibited the growth of all cancer cell lines to different extents, but c9,t11-CLA and t10,c12-CLA inhibited or stimulated the growth of the cancer cell lines. NCI-N87 cells were the most sensitive to growth inhibition and apoptosis from all CLA isomers tested. In NCI-N87 cells, CLA isomers reduced the release of arachidonic acid (AA) via the inhibition of cytosolic phospholipase A2 (cPLA2) activity, consequently reducing the production of PGE2 through the inhibition of cyclooxygenase-2 (COX-2). The efficacies of CLA isomers were in the following order (from most to least effective): t,t-CLA, t10,c12-CLA and c9,t11-CLA. Overall, these results imply that the anti-proliferative efficacy of t,t-CLA on cancer cells, especially NCI-N87 cells, was greater than other CLA isomers due to its induction of apoptosis through the inhibition of cPLA2 and COX-2 activities.

Effect of Dietary CLA Isomers on Apoptosis and Cell Proliferation in Colonic Mucosa of DMH-Treated Rats

The study was designed to compare the anti-carcinogenic effect of conjugated linoleic acid (CLA) isomers on colon carcinogenesis in 1,2-dimethylhydrazine (DMH)-treated rats by determining the levels of apoptosis, cell proliferation, eicosanoids and 1,2-diacylglycerol (DAG) in colonic mucosa. Sixty male Sprague Dawley rats were randomly divided into 3 groups depending on the types of CLA isomers, i.e. BT group (no CLA contained), CLA-C group (cis-9, trans11 isomer contained), and CLA- T group (trans-10, cis-12 isomer contained). The experimental diet was composed of protein at 20%, carbohydrate at 56.2%, and fat at 14.5% including 0.8% CLA isomers by weight. The experimental diet was fed for 14 weeks with the initiation of intramuscular injection of DMH, which was injected twice a week for 6 weeks to give total dose of l80mg per kg body weight. Two CLA isomers (c9t11 and t10c12) significantly increased the relative percentage of apoptosis but reduced cell proliferation in mucosal cell and also the levels of PGE2, TXB2, and DAG in colonic mucosa. However, there was no significant differences in anti-carcinogenic effect between c9t11 isomer and t10c12 isomer. Overall, colon carcinogenesis could be significantly inhibited by CLA isomers by increasing apoptosis and reducing cell proliferation, the levels of eicosanoids and DAG in colonic mucosa.