Hyun-Ju Yu

Induction of apoptosis by parthenolide in human oral cancer cell lines and tumor xenografts

OBJECTIVES Parthenolide (PTL), a representative sesquiterpene lactone that is responsible for medicinal properties of the feverfew, is known to modulate diverse intracellular signaling pathways, thereby exerting the tumor growth-inhibitory effects. In this study, authors attempted to examine the pro-apoptotic effects and possible biochemical mechanisms of PTL in human oral cancer cell lines and tumor xenografts. MATERIAL AND METHODS The apoptotic effects and related molecular mechanisms of PTL on oral cancer were evaluated using cell viability assay, MTS assay, DAPI staining, western blot analysis, reverse transcriptase-polymerase chain reaction, small interfering RNA transfection and nude mouse xenograft assay. RESULTS PTL treatment increased the cleavage of caspase-3 and poly (ADP-ribose) polymerase (PARP), and the nuclear fragmentation in a concentration- or time-dependent manner. PTL treatment increased Bim protein expression by enhancing the Bim mRNA expression as well as stabilizing Bim protein level. PTL treatment also induced the translocation of cytosolic Bim into the mitochondria and, more importantly, PTL-induced apoptosis was significantly attenuated, when the Bim expression was knockdown by siRNA transfection. PTL treatment also induced death receptor 5 (DR5) protein expression and this event was closely correlated with an increase in the cleavage of caspase-8 and formation of truncation of Bid (t-Bid). Finally, PTL shrunk tumor size and volume resulting from apoptotic cell death by increasing Bim and DR5 whereas there were no abnormal histopathological findings in normal organs. CONCLUSION This study proposes that PTL is a strong apoptotic inducer that deserves the further investigations for potential chemotherapeutic agent of human oral cancers.

In Vitro Assessment of the Anticancer Potential of Evodiamine in Human Oral Cancer Cell Lines.

Evodiamine, a bioactive alkaloid, has been regarded as having antioxidant, antiinflammatory, and anticancer properties. In the present study, we explored the effects of evodiamine on cell growth and apoptosis in human oral cancer cell lines. Our data revealed that evodiamine significantly inhibited the proliferation of human oral cancer cells and resulted in the cleavages of PARP (poly (ADP‐ribose) polymerase) and caspase‐3, in addition to causing the typical characteristics of apoptosis. Evodiamine also increased Bax protein levels and caused translocation of Bax into mitochondria and Bax oligomerization. In addition, evodiamine decreased expression of myeloid cell leukemia (Mcl‐1) at the transcriptional modification, and knockdown of Mcl‐1 clearly resulted in an increase in expression of Bax and active Bax, resulting in induction of apoptosis. Evodiamine reduced expression of phosphorylated AKT, and LY294002 potentiated evodiamine‐induced apoptosis by regulating Mcl‐1 protein. Our results suggest that evodiamine induces apoptosis in human oral cancer cells through the AKT pathway. These findings provide a rationale for its clinical application in the treatment of oral cancer. Copyright

Signal transducer and activators of transcription 3 regulates cryptotanshinone-induced apoptosis in human mucoepidermoid carcinoma cells

Background: Cryptotanshinone (CT) is a biologically active compound from the root of Salvia miltiorrhiza that has been reported to induce apoptosis in various cancer cell lines; but, it has not yet been fully explored in human mucoepidermoid carcinoma (MEC). Objective: Here, we demonstrated the apoptotic effects and its related mechanism in MC-3 and YD-15 human MEC cell lines. Materials and Methods: The effects of CT on apoptotic activity were evaluated by cell proliferation assay, Western blotting, 4’-6-diamidino-2-phenylindole staining, reverse transcription-polymerase chain reaction, and luciferase assay. Results: Our data show that CT treatment of MC-3 cells results in anti-proliferative and apoptotic activities in MC-3 and it is accompanied by a decrease in phosphorylation and dimerization of signal transducer and activators of transcription 3 (STAT3). CT decreased the expression levels of myeloid cell leukemia-1 (Mcl-1) and surviving, whereas Bcl-xL expression was not changed. CT clearly regulates survivin protein at a transcriptional level and alters Mcl-1 through proteasome-dependent protein degradation. In addition, CT-induced apoptotic cell death in YD-15, another human MEC cell line, was associated with the inhibition of STAT3 phosphorylation. Conclusion: These data suggest that CT could be a good apoptotic inducer through modification of STAT3 signaling in human MEC cell lines.

Silymarin and its active component silibinin act as novel therapeutic alternatives for salivary gland cancer by targeting the ERK1/2-Bim signaling cascade

PurposeApproximately 20% of all salivary gland cancer patients who are treated with current treatment modalities will ultimately develop metastases. Its most common form, mucoepidermoid carcinoma (MEC) is a highly aggressive tumor with an overall 5-year survival rate of ~30%. Until now, several chemotherapeutic drugs have been tested for the treatment of salivary gland tumors, but the results have been disappointing and the drugs often cause unwanted side effects. Therefore, several recent studies have focused on the potential of alternative and/or complementary therapeutic options, including the use of silymarin.MethodsThe effects of silymarin and its active component silibinin on salivary gland cancer-derived MC3 and HN22 cells and their underlying molecular mechanisms were examined using trypan blue exclusion, 4′-6-diamidino-2-phenylindole (DAPI) staining, Live/Dead, Annexin V/PI staining, mitochondrial membrane potential (ΔΨm) measurement, quantitative RT-PCR, soft agar colony formation and Western blotting analyses.ResultsWe found that silymarin and silibinin dramatically increased the expression of the pro-apoptotic protein Bim in a concentration- and time-dependent manner and, concomitantly, induced apoptosis in MC3 and HN22 cells. We also found that ERK1/2 signaling inhibition successfully sensitized these cells to the apoptotic effects of silymarin and silibinin, which indicates that the ERK1/2 signaling pathway may act as an upstream regulator that modulates the silymarin/silibinin-induced Bim signaling pathway.ConclusionsTaken together, we conclude that ERK1/2 signaling pathway inhibition by silymarin and silibinin increases the expression of the pro-apoptotic Bcl-2 family member Bim which, subsequently, induces mitochondria-mediated apoptosis in salivary gland cancer-derived cells.

Inhibition of myeloid cell leukemia‐1: Association with sorafenib‐induced apoptosis in human mucoepidermoid carcinoma cells and tumor xenograft

The purpose of our study was to investigate the anticancer effect of sorafenib on mucoepidermoid carcinoma (MEC) and find its new molecular mechanism.

Nitidine chloride acts as an apoptosis inducer in human oral cancer cells and a nude mouse xenograft model via inhibition of STAT3

Nitidine chloride (NC) is a natural alkaloid compound derived from the plant Zanthoxylum nitidum and is known for its therapeutic anticancer potential. In this study, we investigated the effects of NC on growth and signaling pathways in human oral cancer cell lines and a tumor xenograft model. The apoptotic effects and related molecular targets of NC on human oral cancer were investigated using trypan blue exclusion assay, DAPI staining, Live/Dead assay, Western blotting, Immunohistochemistry/Immunofluorescence and a nude mouse tumor xenograft. NC decreased cell viability in both HSC3 and HSC4 cell lines; further analysis demonstrated that cell viability was reduced via apoptosis. STAT3 was hyper-phosphorylated in human oral squamous cell carcinoma (OSCC) compared with normal oral mucosa (NOM) and dephosphorylation of STAT3 by the potent STAT3 inhibitor, cryptotanshinone or NC decreased cell viability and induced apoptosis. NC also suppressed cell viability and induced apoptosis accompanied by dephosphorylating STAT3 in four other oral cancer cell lines. In a tumor xenograft model bearing HSC3 cell tumors, NC suppressed tumor growth and induced apoptosis by regulating STAT3 signaling without liver or kidney toxicity. Our findings suggest that NC is a promising chemotherapeutic candidate against human oral cancer.

Apoptosis induced by caffeic acid phenethyl ester in human oral cancer cell lines: Involvement of Puma and Bax activation

OBJECTIVE Caffeic acid phenethyl ester (CAPE), a natural honeybee product exhibits a spectrum of biological activities including antimicrobial, anti-inflammatory, antioxidant and antitumor actions. The purpose of this research was to investigate the anticancer potential of CAPE and its molecular mechanism in human oral cancer cell lines (YD15, HSC-4 and HN22 cells). DESIGN To determine the apoptotic activity of CAPE and identify its molecular targets, trypan blue exclusion assay, soft agar assay, Western blot analysis, DAPI staining, and live/dead assay were performed. RESULTS CAPE significantly suppressed transformation of neoplastic cells induced by epidermal growth factor (EGF) and 12-O-tetradecanoylphorbol 13-acetate (TPA) without inhibiting growth. CAPE treatment inhibited cell growth, increased the cleavages of caspase-3 and poly (ADP-ribose) polymerase (PARP), and augmented the number of fragmented nuclei in human oral cancer cell lines. CAPE activated Bax protein causing it to undergo a conformational change, translocate to the mitochondrial outer membrane, and oligomere. CAPE also significantly increased Puma expression and interestingly Puma and Bax were co-localized. CONCLUSION Overall, these results suggest that CAPE is a potent apoptosis-inducing agent in human oral cancer cell lines. Its action is accompanied by up-regulation of Bax and Puma proteins.

The Effects of Fucoidan on the Activation of Macrophage and Anticancer in Gastric Cancer Cell

This study was designed to investigate the effect of fucoidan on the activation of macrophage and on induction of apoptosis in AGS cell. To measure the activity of macrophages, NO and TNF-α assays were per- formed in Raw 264.7 cell. Treatment with fucoidan significantly increased production of NO and TNF-α, indicating activation of macrophages. The result of MTT assay shows that cell viability was significantly decreased in a dose and time-dependent manner. Fucoidan increased to enhance mitochondrial membrane permeability, as well as the cyto- chrome c release from the mitochondria. Fucoidan decreased Bcl-2 and XIAP expression, whereas the expression of Bax was increased in a time-dependent manner compared to the control. In addition, the active forms of caspase-9 were increased, and the inactivation of Akt was decreased in a time-dependent manner. Caspase inhibitor, z-VAD- FMK, canceled the apoptosis of fucoidan, expression of Bax and caspase-9 were decrease. These results indicate that fucoidan induces activation of macrophage and apoptosis through activation of caspase on AGS cell.

Apoptosis induced by methanol extract of Potentilla discolor in human mucoepidermoid carcinoma cells through STAT3/PUMA signaling axis

Potentilla discolor has been used in traditional Chinese medicine for the treatment of hyperglycemia. However, the potential role of Potentilla discolor against cancer and its mode of action remain to be fully elucidated. The present study explored the apoptotic effect of methanol extract of Potentilla discolor (MEPD) in human mucoepidermoid carcinoma (MEC) cell lines of salivary glands. MEPD markedly suppressed the growth and induced apoptotic cell death in MC3 and YD15 cells. MEPD treatment significantly upregulated the expression of PUMA and reduced STAT3 phosphorylation. Overexpression of STAT3 partially recovered the growth of MEC cells inhibited by MEPD. In addition, dephosphorylation of STAT3 by cryptotanshinone (a potent STAT3 inhibitor) was sufficient to inhibit the growth of MEC cells and induce apoptosis via affecting PUMA protein. These results suggest that MEPD has a potential anticancer property via the STAT3/PUMA signaling axis in human MEC cells of salivary gland.