Anticancer effects of Ixeris dentata (Thunb. ex Thunb.) nakai extract on human melanoma cells A375P and A375SM.

ETHNOPHARMACOLOGICAL RELEVANCE: The plant species Taraxacum coreanum (TC), Youngia sonchifolia (YS), and Ixeris dentata (ID) belong to the family Compositae and are used for medicinal purposes in traditional medicine. However, the anticancer effects of TC, YS, and ID extracts and the underlying molecular mechanisms in melanoma cells have not been elucidated. AIM OF THE STUDY: To investigate the potential anticancer effects of TC, YS, and ID extracts on human melanoma cells and explore the potential pharmacological mechanisms in vitro and in vivo. MATERIALS AND METHODS: In this comparative study, we investigated the effects of TC, YS, and ID extracts on cell proliferation in human melanoma A375P and A375SM cells using MTT[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays. Apoptotic cells were detected by 4',6-diamidino-2-phenylinodole (DAPI) staining. We also investigated whether the growth-inhibitory effects were associated with the induction of apoptosis and whether the mechanisms of cell death were the result of signaling molecules such as p53, Bax, Bcl-2, caspase-9, Poly-ADP ribose polymerase (PARP), and Erk (Extracellular signal-regulated protein kinase) 1/2. The in vivo antitumor effects were evaluated by measuring the tumor volume and weight and performing Terminal deoxynucleotidyl transferase (TdT) dUTP Nick End Labeling (TUNEL) assay and immunohistochemistry (IHC) in tumor xenograft models. RESULTS: TC, YS, and ID extracts effectively inhibited the growth of A375P and A375SM cells. In addition, several apoptotic events were observed following treatment, including DNA fragmentation and chromatin condensation by DAPI staining. The extracts increased p53, Bax, cleaved-caspase-9 and cleaved-PARP expression, whereas the expression of Bcl-2 was decreased in both cell lines. Furthermore, ID extract significantly inhibited the activation of Erk1/2 in both cell lines. Among the three extracts, ID had the strongest apoptotic effects. The administration of ID extract to mice inhibited tumor growth without any toxicity following 4 weeks of treatment. This extract increased the expression of apoptotic cells and p53 protein and decreased phospho-Erk1/2 protein. CONCLUSION: TC, YS, and ID extracts suppress the growth of human melanoma cells through apoptosis. Among these extracts, ID has the strongest anticancer and apoptotic effects. It induces apoptosis through the inhibition of Erk1/2 in A375P and A375SM human melanoma cells and in tumor xenograft models and may be a potential chemotherapeutic agent against melanoma.

Convallaria keiskei as a novel therapeutic alternative for salivary gland cancer treatment by targeting myeloid cell leukemia-1.

BACKGROUND: Various chemotherapeutic agents have been used largely for the treatment of salivary gland cancer. However, results are disappointing, and these agents can cause some serious side effects. Therefore, recent studies have focused on the possible roles of natural products to overcome these limitations. METHODS: Salivary gland cancer cells treated with or without Convallaria keiskei (MECK) for 24 hours. Apoptotic changes were evaluated by live/dead assay, immunoblotting, and expression levels of caspase-3 and B-cell lymphoma-2 family member. RESULTS: MECK significantly inhibited salivary gland cancer growth. At the molecular level, MECK dramatically reduced myeloid cell leukemia-1 (Mcl-1) in a translation-dependent manner and thereby induced apoptosis through Bax/Bid. Furthermore, we found that Mcl-1 could be a potential therapeutic target of MECK-induced apoptosis and its stability is regulated by extracellular signal-regulated kinases 1/2 (ERK1/2) signaling CONCLUSION: MECK can be used as a safe and efficient therapeutic alternative for the treatment of salivary gland cancer. © 2015 Wiley Periodicals, Inc. Head Neck 38: E761-E770, 2016.

Apoptotic effect of hot water extract of Sanguisorba officinalis L. in human oral cancer cells.

Sanguisorba officinalis L. has been used in traditional Asian medicine to treat diseases including diarrhea, chronic intestinal infections, duodenal ulcers and bleeding. This study examined the antiproliferative effects and apoptotic activity of hot water extract of S. officinalis L. (HESO) on HSC4 and HN22 human oral cancer cells. The effects of HESO were evaluated by the 3-(4,5-dimethylthiazol-20yl)-(3-carboxymethoxyphenyl)-2-(4-sulphophenyl)-2H-tetrazolium (MTS) assay, 4'-6-diamidino-2-phenylindole (DAPI) staining and western blot analysis. HESO was found to inhibit cell growth and induce apoptosis in HSC4 and HN22 oral cancer cells. HESO downregulated myeloid cell leukemia-1 (Mcl-1) in HSC4 cells and was associated with the activation of Bak, resulting in Bak oligomerization on the mitochondrial outer membrane. HESO did not alter Mcl-1 expression in HN22 cells, but it decreased Sp1 expression. The downregulation of Sp1 by HESO in HN22 cells resulted in a decrease in survivin, a downstream target protein of Sp1. These results suggested that HESO inhibited the growth of oral cancer through either Mcl-1 or Sp1, indicating that HESO may serve as a potential drug candidate against oral cancer.

KO-202125, a sauristolactam derivate, induces apoptosis to prevent KB human oral squamous carcinoma cells through inhibition of cyclooxygenase-2 expression.

In a previous study, we demonstrated that cyclooxygenase-2 (COX-2) is overexpressed in Korean patients having oral cancer. The goal of this study was to study whether KO-202125 (KO), a sauristolactam derivative in KB human oral squamous carcinoma cells, inhibits the activity of COX-2 enzyme and induces apoptotic cell death. In this study, it was shown that KO inhibited COX-2 mRNA and protein and its catalytic activity (prostaglandin E2), but not COX-1. The antiproliferative effect of KO on KB cells was also examined. The results showed that KO significantly decreased the number of viable cells and showed morphological changes in a concentration-dependent manner. The decrease in cell number was associated with apoptotic cell death evidenced by cleaved poly ADP ribose polymerase (PARP), nuclear fragmentation, sub-G1 population and annexin V positivity. Interestingly, KO is more potent than celecoxib, which is a well-known selective COX-2 inhibitor, although more studies are needed to prove it. Altogether, these results show that KO can act as a potent antioral cancer drug candidate by regulating COX-2 activity.