Because twigs of Cinnamomum cassia (TC) have been reported to exert anti-cancer activity, the mechanistic study for TC’s anti-cancer activity is required. Thus, we elucidated the potential molecular mechanism of TC’s anti-proliferative effect and the induction of apoptosis in human colorectal cancer cells. How water extracts form TC (TC-HW) was used in this study. Anti-cell proliferative effect of TC-HW was evaluated by MTT assay. The change of protein or mRNA level by TC-HW was evaluated by Western blot and RT-RCR, respectively. The promoter construct for ATF3, NF-κB, TOP-FLASH or FOP-FLASH was used for the investigation of the transcriptional activity for ATF3, NF-κB or Wnt. siRNA for ATF3 or p65 was used for the knockdown of ATF3 and p65. TC-HW reduced the cell viability in human colorectal cancer cells. TC-HW decreased cyclin D1 protein level through cyclin D1 degradation via GSK3β-dependent threonine-286 (T286) phosphorylation of cyclin D1, indicating that cyclin D1 degradation may contribute to TC-HW-mediated decrease of cyclin D1 protein level. TC-HW downregulated the expression of cyclin D1 mRNA level and inhibited Wnt activation through the downregulation of β-catenin and TCF4 expression, indicating that inhibition of cyclin D1 transcription may also result in TC-HW-mediated decrease of cyclin D1 protein level. In addition, TC-HW was observed to induce apoptosis through ROS-dependent DNA damage. TC-HW-induced ROS increased NF-κB and ATF3 activation, and inhibition of NF-κB and ATF3 activation attenuated TC-HW-mediated apoptosis. Our results suggest that TC-HW may suppress cell proliferation through the downregulation of cyclin D1 via proteasomal degradation and transcriptional inhibition, and may induce apoptosis through ROS-dependent NF-κB and ATF3 activation. These effects of TC-HW may contribute to the reduction of cell viability in human colorectal cancer cells. From these findings, TC-HW has potential to be a candidate for the development of chemoprevention or therapeutic agents for human colorectal cancer.

Although it has been reported to contain high polyphenols, the pharmacological studies of the calyx of Diospyros kaki Thunb (DKC) have not been elucidated in detail. In this study, we elucidated anti-cancer activity and potential molecular mechanism of DKC against human colorectal cancer cells. Anti-cell proliferative effect of 70% ethanol extracts from the calyx of Diospyros kaki (DKC-E70) was evaluated by MTT assay. The effect of DKC-E70 on the expression of cyclin D1 in the protein and mRNA level was evaluated by Western blot and RT-PCR, respectively. DKC-E70 suppressed the proliferation of human colorectal cancer cell lines such as HCT116, SW480, LoVo and HT-29. Although DKC-E70 decreased cyclin D1 expression in protein and mRNA level, decreased level of cyclin D1 protein by DKC-E70 occurred at the earlier time than that of cyclin D1 mRNA, which indicates that DKC-E70-mediated downregulation of cyclin D1 protein may be a consequence of the induction of degradation and transcriptional inhibition of cyclin D1. In cyclin D1 degradation, we found that cyclin D1 downregulation by DKC-E70 was attenuated in presence of MG132. In addition, DKC-E70 phosphorylated threonine-286 (T286) of cyclin D1 and T286A abolished cyclin D1 downregulation by DKC-E70. We also observed that DKC-E70-mediated T286 phosphorylation and subsequent cyclin D1 degradation was blocked in presence of the inhibitors of ERK1/2, p38 or GSK3β. In cyclin D1 transcriptional inhibition, DKC-E70 inhibited the expression of β-catenin and TCF4, and β–catenin/TCF-dependent luciferase activity. Our results suggest that DKC-E70 may downregulate cyclin D1 as one of the potential anti-cancer targets through cyclin D1 degradation by T286 phosphorylation dependent on ERK1/2, p38 or GSK3β, and cyclin D1 transcriptional inhibition through Wnt signaling. From these findings, DKC-E70 has potential to be a candidate for the development of chemoprevention or therapeutic agents for human colorectal cancer.

Sageretia thea (S. thea) has been used as the medicinal plant for treating hepatitis and fevers in Korea and China. Recently, anticancer activity of S. thea has been reported, but the potential mechanism for the anti-cancer property of S. thea is still insufficient. Thus, we evaluated whether extracts from the leaves (STL) and branches (STB) of S. thea exert anticancer activity and elucidated its potential mechanism in SW480 cells. MTT assay was performed for measuring cell viability. Western blot and RT-PCR were used for analyzing the level of protein and mRNA, respectively. Treatment of STL or STB decreased the cell viability and induced apoptosis in SW480 cells. Decreased level of cyclin D1 protein was observed in SW480 cells treated with STL or STB, but no change in cyclin D1 mRNA level was observed with the treatment of STL or STB. MG132 blocked downregulation of cyclin D1 protein by STL or STB. Thr286 phosphorylation of cyclin D1 by STL or STB occurred faster than downregulation of cyclin D1 protein in SW480 cells. When SW480 cells were transfected with T286A-cyclin D1, cyclin D1 degradation by STL or STB did not occur. Inhibition of GSK3β and cyclin D1 nuclear export attenuated STL or STB-mediated cyclin D1 degradation. In addition, STL or STB increased HO-1 expression, and the inhibition of HO-1 attenuated the induction of apoptosis by STL or STB. HO-1 expression by STL or STB resulted from Nrf2 activation through ROS-dependent p38 activation. These results indicate that STL or STB may induce GSK3β-dependent cyclin D1 degradation, and increase HO-1 expression through activating Nrf2 via ROS-dependent p38 activation, which resulted in the decrease of the viability in SW480 cells. These findings suggest that STL or STB may have great potential for the development of anti-cancer drug.

In this study, we evaluated the functionality of water extracts from the fruit of Actinidia polygama (APF) in macrophages. The APF is a medicinal plant belonging to Actinidiaceae, it has been reported to exert anti-inflammatory, analgesic and hypouricemic activities. However, the potential mechanism for the immune activation of the APF is still insufficient. So, we evaluated whether APF exerts immune activation activities and elucidated its potential mechanism in macrophages. The APF dose-dependently increased the production of immunomodulators in macrophages. The inhibition of Toll-like receptor 4 (TLR4) blocked APF-mediated production of immunomodulators in RAW264.7 cells. In addition, APF-mediated production of immunomodulators was attenuated by MAPKs and NF-κB inhibition in RAW264.7 cells. Also, we analyzed the sugars content of the APF. The contents of glucose, galactose and fructose were 3597, 904, 7582 mg/L, respectively. These results suggest that the APF may have great potential for the development of immunomodulatory drugs.

Berchemia floribunda (Wall.) Brongn. (BF), which belongs to Rhamnaceae, is a special plant of Anmyeon Island in Korea. BF has been reported to have antioxidant and whitening effects. However, the anti-inflammatory activity of BR has not been elucidated. In this study, we evaluated the anti-inflammatory effect of leaves (BR-L), branches (BR-B) and fruit (BR-F) extracted with 70% ethanol of BR and elucidated the potential signaling pathway in LPS-induced RAW264.7 cells. BR-L showed a strong anti-inflammatory activity through the inhibition of NO production. BR-L significantly suppressed the production of the pro-inflammatory mediators such as iNOS, COX-2, IL-1β, IL-6 and TNF-α in LPS-stimulated RAW264.7 cells. BR-L suppressed the degradation and phosphorylation of IκB-α, which contributed to the inhibition of p65 nuclear accumulation and NF-κB activation. BR-L obstructed the phosphorylation of MAPKs (ERK1/2, p38 and JNK) in LPS-stimulated RAW264.7 cells. Consequently, these results suggest that BR-L may have great potential for the development of anti-inflammatory drugs to treat acute and chronic inflammatory disorders.