Gene Profiling of Cannabis-sativa-mediated Apoptosis in Human Melanoma Cells.

BACKGROUND/AIM: Malignant melanoma is an aggressive skin cancer, accounting for the majority of skin cancer deaths. Prognosis is often poor and finding effective treatment remains a challenge. Tetrahydrocannabinol (THC) and cannabidiol (CBD) are main bioactive components of Cannabis sativa plant extracts that have been shown to exert anti-tumor effects. In this study, we aimed to perform gene expression analysis of human melanoma A375 cells following stimulation with C. sativa extracts. MATERIALS AND METHODS: Gene expression profiles of A375 human melanoma and Vero (control) cell lines were evaluated by RNA sequencing and quantitative real-time PCR. RESULTS: Flow cytometry showed that the THC+CBD cannabis fractions induced apoptosis on A375 cells. Induction of apoptosis was accompanied by a notable up-regulation of DNA damage inducible transcript 3 (DDIT), nerve growth factor receptor (NGFR), colony-stimulating factor 2 (CSF2), growth arrest and DNA damage inducible beta (GADD45B), and thymic stromal lymphopoietin (TSLP) genes and down-regulation of aryl hydrocarbon receptor nuclear translocator 2 (ARNT2), cyclin E2 (CCNE2), integrin subunit alpha 9 (ITGA9), proliferating cell nuclear antigen (PCNA) and E2F transcription factor 1 (E2F1) genes. Treatment of A375 cells with the THC+CBD fraction inhibited the phosphorylation of ERK1/2 signaling pathway, which regulates melanoma cell proliferation. We showed that the THC+CBD combination disrupted melanoma cell migration. CONCLUSION: Use of C. sativa-derived extracts containing equal amounts of THC and CBD is proposed as a potential treatment of melanoma.

Antiproliferative Activity and Induction of Apoptosis in Human Melanoma Cells by Houttuynia cordata Thunb Extract.

BACKGROUND/AIM: To analyze the apoptotic effect of Houttuynia cordata Thunb (HCT) extract on human melanoma A375 cells and its underlying mechanisms. MATERIALS AND METHODS: The effects of HCT on cell death were determined using the MTT assay. Hoechst 33342 staining was conducted to confirm the detection of cell apoptosis. Caspase-3 and caspase-8 mRNA and cleaved protein levels were investigated by RT-PCR and western blotting, respectively. The release of high mobility group box 1 (HMGB1) and phosphorylation of mitogen-activated protein kinase (MAPK) were determined by ELISA. RESULTS: Caspase-3 and caspase-8 specific inhibitors suppressed HCT-induced cell death. HCT increased caspase-3 and caspase-8 mRNA, protein levels, and caspase activities in a concentration- and time-dependent manner. HCT induced MAPK phosphorylation in a time-dependent fashion. Pretreatment of cells with a selective inhibitor of p38 MAPK reduced apoptosis and reversed the levels of HMGB1 release in response to HCT treatment. CONCLUSION: HCT induces A375 programmed cell death by activating the caspase-dependent pathway and by p38 phosphorylation associated with HMGB1 reduction.

Green tea extract supplement inhibition of HMGB1 release in rats exposed to cigarette smoke.

Tobacco-smoke exposure is linked to carcinogenic, oxidative and inflammatory cellular reactions. Green tea has been reported to have anti-release properties against various pro-inflammatory cytokines. To determine the effects of green tea extract (GTE) on serum high mobility group box-1 (HMGB1) levels in rats exposed to cigarette smoke (CS), we divided rats into 4 treatment groups: (1) CS only, (2) dietary supplement with GTE (3 mg/d) and CS (GCS1), (3) dietary supplement with GTE (4.5 mg/d) and CS (GCS2) and (4) a control group. HMGB1 and cotinine serum levels were analyzed by ELISA. The average serum HMGB1 level in the CS group was significantly higher than the other groups (p < 0.01), indicating the release of HMGB1 into the blood was stimulated by CS exposure, while GTE consumption suppressed HMGB1 levels. Rats exposed to CS had an average serum cotinine level of 37 ng/ml, indicating tobacco related compounds were present in the rats' blood. However, treatment with GTE did not reduce cotinine levels in all groups. Cotinine stimulated HMGB1 secretion in a dose- and time-dependent manner, and HMGB1 levels were suppressed by GTE in murine macrophage cell lines. Our results show GTE supplementation may offer beneficial systemic effects and suppress HMGB1 by protecting against cell inflammation.

Mechanism of HMGB1 release inhibition from RAW264.7 cells by oleanolic acid in Prunus mume Sieb. et Zucc.

High mobility group box-1 protein (HMGB1), primarily from the nucleus, is released into the extracellular milieu either passively from necrotic cells or actively through secretion by monocytes/macrophages. Extracellular HMGB1 acts as a potent inflammatory agent by promoting the release of cytokines such as tumor necrosis factor (TNF)-alpha, has procoagulant activity, and is involved in death due to sepsis. Accordingly, HMGB1 is an appropriate therapeutic target. In this study, we found that an extract of Prunus mume Sieb. et Zucc. (Ume) fruit (Ume extract), an abundant source of triterpenoids, strongly inhibited HMGB1 release from lipopolysaccharide (LPS)-stimulated macrophage-like RAW264.7 cells. The inhibitory effect on HMGB1 release was enhanced by authentic oleanolic acid (OA), a naturally occurring triterpenoid. Similarly, the HMGB1 release inhibitor in Ume extract was found to be OA. Regarding the mechanisms of the inhibition of HMGB1 release, the OA or Ume extract was found to activate the transcription factor Nrf2, which binds to the antioxidative responsive element, and subsequently the heme oxygenase (HO)-1 protein was induced, indicating that the inhibition of HMGB1 release from LPS-stimulated RAW264.7 cells was mediated via the Nrf2/HO-1 system; an essentially antioxidant effect. These results suggested that natural sources of triterpenoids warrant further evaluation as 'rescue' therapeutics for sepsis and other potentially fatal systemic inflammatory disorders.