In vitro antimetastatic potential of pseudolaric acid B in HSC-3 human tongue squamous carcinoma cell line.

OBJECTIVE: Pseudolaric acid B (PAB) is a novel diterpenoid derived from the traditional Chinese medicinal herb Cortex pseudolaricis that exerts anticancer, anti-inflammatory, and immunomodulatory properties. While the anticancer potential of PAB has been studied, its effects on metastasis have not been well-studied. This study aims to determine the inhibitory effects of PAB on HSC-3 human tongue squamous cell carcinoma (TSCC) cell line. DESIGN: Cell viability and soft agar colony formation assays were conducted to assess cellular proliferation and in vitro tumorigenic capacity of TSCC cells, respectively. Additionally, wound healing, transwell migration, and invasion assays were conducted to monitor the aggressive behavior of TSCC cells. Furthermore, Western blotting analysis was conducted to reveal the signaling pathways involved in the modulation of epithelial-mesenchymal transition (EMT). RESULTS: The migratory and invasive capacities of HSC-3 cells were suppressed by PAB irrespective of their proliferation states. PAB's effects on EMT involved upregulation of E-cadherin expression and downregulation of Twist; these were concomitantly accompanied by downregulated phosphorylation of epidermal growth factor receptor (EGFR). CONCLUSIONS: PAB suppresses human TSCC in vitro by regulating Twist/E-cadherin through the EGFR signaling pathway. PAB may have potential as a candidate antimetastatic drug for TSCC treatment.

Metabolite profiling of a Sargassum micracanthum methanol extract with in vitro efficacy against human head and neck squamous cell carcinoma aggressiveness.

OBJECTIVE: Extracts from the brown algae Sargassum micracanthum have documented anti-viral, anti-oxidant, and anti-inflammatory activities as well as potential anti-tumor efficacy against several cancer types. Here, we evaluated the inhibitory effect and molecular mechanisms of methanol extract of S. micracanthum (MESM) on the aggressiveness of human head and neck squamous cell carcinoma (HNSCC) using in vitro cell culture-based models. DESIGN: To test the potential efficacy of MESM on the migratory and invasive properties of HNSCC cells, we used wound healing, transwell cell migration and invasion assays. Proteome profiling and functional in silico analysis were applied to investigate the possible modes of action by MESM. We also examined the metabolite profiling of MESM using gas chromatography/mass spectrometry. RESULTS: MESM inhibited the motility of human HNSCC cell lines as well as invasiveness without influencing cell survival. Proteome profiling identified 19 oncogenic proteins significantly downregulated by MESM treatment. Protein-protein interaction network and gene ontology analyses revealed that Tie2 and associated angiogenic signaling pathway components were significantly enriched among these downregulated oncogenic proteins, which was confirmed by validating the reduced Tie2 expression in MESM treatment groups. Metabolite profiling of MESM identified six-carbon sugar alcohols such as D-sorbitol and/or D-mannitol as the main bioactive compounds. D-sorbitol and D-mannitol effectively reduced Tie2 expression and the aggressiveness of human HNSCC cell lines. CONCLUSIONS: These findings suggest that six-carbon sugar alcohols in MESM have promising anti-cancer efficacy for the treatment of human HNSCC and further identify Tie2 signaling components as potential treatment targets.

Methanol extract of Sedum oryzifolium and its constituent, trehalose, impede the invasiveness of oral squamous cell carcinoma cell lines via downregulation of Slug.

BACKGROUND: Sedum species are reported to possess diverse pharmacological activities in various solid tumors. However, the anticancer functions of Sedum orizyfolium and its constituents have never been determined in human cancers. PURPOSE: The present study focused on addressing the inhibition efficacy of the methanol extract of S. orizyfolium (MESO) and its constituents and the molecular mechanism underlying invasion and epithelial-to-mesenchymal transition (EMT) in oral squamous cell carcinoma (OSCC) cell lines. STUDY DESIGN/METHODS: After MESO treatment, a wound-healing assay, an invasion assay, and immunocytochemistry were performed in OSCC cell lines, coupled with in silico analysis and immunohistochemistry in OSCC patient samples, to investigate the role of the EMT transcription factor Slug. Trehalose, an active component of MESO, was identified through gas chromatography-mass spectrometry. RESULTS: Among the methanol extracts of 18 various wild plants from South Korea, MESO exhibited the highest anticancer functionality in OSCC cells by downregulating Slug expression. In silico analysis and immunohistochemistry indicated that elevated Slug levels are remarkably associated with tumor progression and invasion in patients with OSCC, suggesting that changes in Slug expression alter EMT progression and invasion in OSCC. Notably, treatment with trehalose, a sugar component of MESO, inhibited invasiveness and Slug expression in OSCC cells. CONCLUSION: Cumulatively, this study highlighted the beneficial role of MESO and trehalose in the inhibition of invasiveness of OSCC cells via suppression of Slug expression and suggested a new design for potential chemotherapeutic drugs against OSCC.

In vitro induction of mitotic catastrophe as a therapeutic approach for oral cancer using the ethanolic extract of Juniperus squamata.

Mitotic catastrophe, a cell death mechanism characterized by abnormal mitosis, has been regarded as a therapeutic approach for the development of anti­cancer drug candidates. The aim of the present study was to investigate the potential effect of the ethanolic extract of Juniperus squamata (EEJS) on the occurrence of mitotic catastrophe in human oral cancer cell lines. The effect of EEJS on the occurrence of mitotic catastrophe was evaluated by measuring cytotoxicity, observing phase­contrast or transmission electron microscope findings, evaluating the appearance of microtubule or chromosome abnormalities, and detecting the phosphorylation of histone H3 (Ser10). The apoptotic effect of EEJS was assessed by detecting cleaved PARP, analyzing the sub­G1 population, Annexin V­FITC/PI double staining, western blot analysis, and the transient transfection of myeloid cell leukemia­1 (Mcl­1) overexpression vectors. EEJS treatment was effective in inhibiting cell proliferation in human oral cancer cell lines. EEJS resulted in the enrichment of enlarged multinucleated cells, the disturbance of microtubule formation, and increased phosphorylation of histone H3 (Ser10), which demonstrates the occurrence of mitotic catastrophe. Additionally, the multinucleated cells underwent apoptotic cell death in a cell context­dependent manner, which was associated with the reduction of Mcl­1 protein levels. Findings of the present study indicate that EEJS could be effective for treating human oral cancer by promoting mitotic catastrophe linked to apoptotic cell death.

Pseudolaric Acid B Induces Growth Inhibition and Caspase-Dependent Apoptosis on Head and Neck Cancer Cell lines through Death Receptor 5.

Pseudolaric Acid B (PAB), diterpenoid isolated from the root bark of Pseudolarix kaempferi Gordon tree (Pinaceae), exhibits an anti-proliferative and apoptotic activity in various cancer cell lines but to date, the effects of PAB on head and neck cancer (HNC) cell lines remain to be elucidated. In this study, we showed that PAB significantly inhibited the viability and caspase-dependent apoptosis in HN22 cell line. PAB-induced apoptosis is through inducing death receptor 5 (DR5) together with the increase in the expression of cleaved caspase-8. It also inhibited the proliferations and induced apoptosis through DR5 in other three HNC cell lines (HSC3, Ca9.22, and HSC4). Extending our in vitro findings, we found that ethanol extract of Pseudolarix kaempferi (2.5 mg/kg/day) reduced tumor growth in a xenograft model bearing HN22 cell line without any change in body weight. DR5 were also found to be increased in tumors tissue of PAB-treated mice without any apparent histopathological changes in liver or kidney tissues. Taken together, PAB may be a potential lead compound for chemotherapeutic agents against head and neck cancer.

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.

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

PURPOSE: Approximately 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. METHODS: The 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. RESULTS: We 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. CONCLUSIONS: Taken 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.

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.

Anti-cancer effects of traditional Korean wild vegetables in complementary and alternative medicine.

This research study explored the anti-cancer effects of natural materials in South Korea. Although South Korea has a long history of traditional medicine, many natural materials of South Korea have not yet been introduced to the rest of the world because of language barriers and inconsistent study conditions. In the past 3 years, 56 papers introducing 56 natural materials, which have anti-cancer effects, have been published by scientists in South Korea. Further, these studies have introduced five kinds of natural materials presented in research papers that were written in Korean and are therefore virtually unknown overseas. The anti-cancer effects were confirmed by 2-3 cancer markers in the majority of the studies, with the most common targets being breast cancer cells and gastric cancer cells. These cancers have the greatest incidence in South Korea. The natural materials studied not only exhibit anti-cancer activity but also display anti-inflammatory, anti-oxidative stress, and anti-diabetic activities. They have not yet been used for the direct treatment of disease but have potential as medicinal materials for alternative and complementary medicine for the treatment of many modern diseases. Many natural materials of South Korea are already known all over the world, and with this study, we hope to further future research to learn more about these natural medicines.

Anticancer activity of Ashwagandha against human head and neck cancer cell lines.

BACKGROUND: The aim of this study was to determine the apoptotic activity of methanol extract of Ashwagandha (MEAG) and in human head and neck squamous cell carcinoma (HNSCC) cells and to investigate the underlying mechanisms. METHODS: We investigated the effects of MEAG on programmed cell death in HNSCC cells using a Live/Dead assay, detection of nuclear morphologic changes, Mitotracker, siRNA knockdown, and RT-PCR. RESULTS: Treatment with MEAG showed dose-dependent growth-inhibitory activity that attribute to caspase-dependent apoptosis. Loss of mitochondrial membrane potential, release of cytochrome c, and activation of caspase 9 suggested that MEAG leads to activation of mitochondria-mediated apoptosis. MEAG selectively upregulated the expression of Bim protein at the transcriptional level and induced the translocation of Bim into the mitochondria. Knockdown of Bim by siRNA partially blocked MEAG-mediated apoptosis. MEAG also caused an increase in truncated Bid (t-Bid), cleaved caspase-8, and death receptor 5 (DR5). Interestingly, withaferin A (WA), a bioactive component of MEAG, clearly induced apoptosis accompanied by upregulation of Bim, t-Bid, caspase-8, and DR5 similar to the effects of MEAG. CONCLUSIONS: These suggest that MEAG and WA may be potential natural materials for the treatment of HNSCC.

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.

Targeting ERK1/2-bim signaling cascades by BH3-mimetic ABT-737 as an alternative therapeutic strategy for oral cancer.

To date, many different chemotherapeutic agents have been widely used as common treatments for oral cancers. However, their therapeutic effects have been disappointing, and these agents may have unwanted side effects. Among the many regulatory factors, overexpression of pro-survival Bcl-2 family members may promote resistance to chemotherapeutic drugs in many tumors. The BH3 domain-only proteins effectively antagonize their apoptotic activities. Therefore, there is substantial interest in developing chemotherapeutic drugs that directly target pro-survival Bcl-2 proteins by mimicking the BH3 domain and unleashing pro-apoptotic molecules in tumor cells. Among the numerous available small molecule BH3 mimetics, ABT-737, a potent small molecule that binds to Bcl-2/Bcl-xL with high affinity, has anti-tumor activity in a wide variety of cancer cells. However, the effects of ABT-737 on human oral cancers and the underlying molecular mechanisms have not previously been elucidated. In the present study, we observed that inactivation of the ERK1/2 signaling pathway using ABT-737 dramatically increased the expression of pro-apoptotic protein Bim via transcriptional and/or posttranslational regulation, in a cell type-dependent manner, inducing mitochondria-mediated apoptosis of human oral cancer cells. To the best of our knowledge, this is the first demonstration of the antitumor effects of ABT-737 on 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.

Down-regulation of Akt by methanol extracts of Impatiens balsamina L. promotes apoptosis in human oral squamous cell carcinoma cell lines.

BACKGROUND: The apoptotic activity of methanol extracts of Impatiens balsamina L. (MEIB) and related mechanisms in human oral squamous cell carcinoma (OSCC) cells have been systematically investigated. METHODS: The effects of MEIB on human OSCC cell lines were investigated using trypan blue exclusion assay, MTS assay, Western blot, 4'-6-diamidino-2-phenylindole (DAPI) staining, Live/Dead assay, Immunohistochemistry, reverse transcription-polymerase chain reaction, and promoter assay. RESULTS: MEIB decreased cell viability and induced apoptosis in HSC-4 cells. Higher levels of p-Akt expression were observed in OSCC than in normal oral mucosa (NOM), and it correlated with poor survival of the patients. MEIB dephosphorylated p-Akt and decreased Akt expression through proteasome-dependent degradation. LY294002 (PI3K inhibitor) decreased p-Akt and Akt, resulting in enhancing MEIB-induced apoptosis. MEIB down-regulated the expression level of survivin protein at the transcriptional level and YM155 (survivin inhibitor) decreased survivin, which facilitated MEIB-induced apoptosis. MEIB and LY294002 significantly increased Bax, thereby inducing the conformational change, mitochondrial translocation, and oligomerization. In addition, MEIB-induced growth inhibition and apoptosis in OSC-20, another human OSCC cells were mediated by regulating Akt and it downstream targets, survivin and Bax. CONCLUSIONS: These results suggest that MEIB may serve as a potential drug candidate for the treatment of human OSCC.

Apoptotic effect of methanol extract of Picrasma quassioides by regulating specificity protein 1 in human cervical cancer cells.

In the present study, we examined the effects of methanol extracts of Picrasma quassioides (MEPQ) on apoptosis in human cervical cancer cells. The results showed that MEPQ decreased the viability and induced caspase-dependent apoptosis in HEp-2 cells. MEPQ decreased specificity protein 1 (Sp1) in HEp-2 cells, whereas Sp1 mRNA was not changed. We found that MEPQ reduced Sp1 protein through proteasome-dependent protein degradation, but not the inhibition of protein synthesis. Also, MEPQ increased the expressions of Bad and truncated Bid (t-Bid) but did not alter other Bcl-2 family members. The knock-down of Sp1 by both Sp1 interfering RNA and Mithramycin A, Sp1 specific inhibitor clearly increased Bad and t-Bid expression to decrease cell viability and induce apoptosis. In addition, MEPQ inhibited cell viability and induced apoptotic cell death through the modulation of Sp1 in KB cells. These results suggest that MEPQ may be a potential anticancer agent for human cervical cancer.

Extracellular signal­regulated kinase inhibition is required for methanol extract of Smilax china L.­induced apoptosis through death receptor 5 in human oral mucoepidermoid carcinoma cells.

Smilax china L., a well­known Chinese traditional medicine, has been used as an anti­inflammatory, anti­cancer and analgesic agent, but its role has not yet been fully elucidated in oral mucoepidermoid carcinoma (MEC). The present study focused on addressing the anticancer activity and molecular mechanism of methanol extract of Smilax china L. (MESC) in MC­3 human oral MEC cells. The results indicated that MESC inhibited cell growth and induced apoptosis in MC­3 cells. These observations were found to correlate with increases in truncated BH3 interacting­domain death agonist and B­cell lymphoma 2 (Bcl­2) interacting mediator of cell death, but not Bcl­2 homologous antagonist killer, Bcl­2­associated X protein, Bcl­2, B­cell lymphoma­extra large and induced myeloid leukemia cell differentiation protein levels. MESC also damaged the mitochondrial membrane potential, cleaved caspase­8 protein and increased death receptor 5 (DR5) protein levels by enhancing the stability of DR5 protein. Furthermore, MESC affected the phosphorylation of extracellular signal­regulated kinase (ERK) only, and did not affect c­Jun N­terminal kinase or p38 phosphorylation. Co­treatment with MESC and an ERK inhibitor (PD98059) significantly increased the expression of DR5 to induce apoptosis in MC­3 cells. Therefore, these results suggest that MESC may induce apoptosis via the ERK pathway and may be a potential anticancer drug candidate against human oral MEC.

Anti-proliferative effect of honokiol in oral squamous cancer through the regulation of specificity protein 1.

Honokiol (HK), a novel plant-derived natural product, is a physiologically activated compound with polyphenolic structure, and has been identified to function as an anticancer agent. It has been widely used in several diseases as a traditional medicine for a long time. We investigated whether HK could show anticancer effects on two oral squamous cell lines (OSCCs), HN-22 and HSC-4. We demonstrated that HK-treated cells showed dramatic reduction in cell growth and apoptotic cell morphologies. Intriguingly, the transcription factor specificity protein 1 (Sp1) was significantly inhibited by HK in a dose-dependent manner. Furthermore, we checked changes in cell cycle regulatory proteins and anti-apoptotic proteins at the molecular level, which are known as Sp1 target genes. The important key regulators in the cell cycle such as p27 and p21 were up-regulated by HK-mediated down-regulation of Sp1, whereas anti-apoptotic proteins including Mcl-1 and survivin were decreased, resulting in caspase-dependent apoptosis. Taken together, results from this study suggest that HK could modulate Sp1 transactivation and induce apoptotic cell death through the regulation of cell cycle and suppression of anti­apoptotic proteins. In addition, HK may be used in cancer prevention and therapies to improve the clinical outcome as an anticancer drug.

4-Deoxypyridoxine improves the viability of isolated pancreatic islets ex vivo.

The successful islet transplantation, for the treatment of type 1 diabetes, depends on the quantity and the quality of transplanted islets. Previously, it has reported that the significant loss of isolated islet mass could be prevented by sphingolipid metabolite, sphinogosine 1-phophate (S1P). This study was performed to elucidate whether the beneficial effects of S1P maintaining isolated pancreatic islets ex vivo are mimicked by modulation of intracellular S1P. We tested the in vitro effect of various agents that modulate intracellular S1P levels in insulinoma cell lines and isolated islets to compare their anti-apoptotic effects with that of S1P. As results, we discovered that 4-deoxypyridoxine (DOP), which inhibits the degradation of intracellular S1P by inhibiting S1P lyase (SPL) activity, minimized the chemically induced apoptosis of insulinoma cell lines as S1P did. Also, supplementation of DOP in the culture media protected the regression of isolated islets that have been maintained ex vivo at least for 18 h providing the evidence of increasing viability of isolated islets with DOP, which impaired SPL activity. In conclusion, these results suggest that the application of SPL inhibitors could be considered as a supplement for the maintenance of viable islets isolated from donor sources in the process of islet transplantation.

In vitro apoptotic effects of methanol extracts of Dianthus chinensis and Acalypha australis L. targeting specificity protein 1 in human oral cancer cells.

BACKGROUND: The aims of this study were to evaluate the apoptotic activities and molecular mechanisms of methanol extracts of Dianthus chinensis (MEDC) and Acalypha australis L. (MEAL) in human oral cancer cells. METHODS: The apoptotic effects and related molecular mechanisms of MEDC and MEAL on oral cancer cells were evaluated using MTS assay, DAPI staining, immunostaining, Western blotting, and reverse transcriptase-polymerase chain reaction. RESULTS: Sp1 was overexpressed in oral tumor tissues compared with normal oral mucosa. Downregulation of Sp1 inhibited the growth of SCC-15 and YD-15 oral cancer cells. MEDC and MEAL inhibited cell growth and induced apoptosis in both cell lines by decreasing the expression of Sp1. In addition, treatment of cells with MEDC and MEAL decreased Mcl-1 expression, which is a downstream target of Sp1. CONCLUSION: Our results indicate that MEDC and MEAL are bioactive natural products that can potentially induce apoptosis of tumor cells that overexpress the Sp1 protein.

Althaea rosea Cavanil and Plantago major L. suppress neoplastic cell transformation through the inhibition of epidermal growth factor receptor kinase.

For thousands of years in Asia, Althaea rosea Cavanil (ARC) and Plantago major L. (PML) have been used as powerful non-toxic therapeutic agents that inhibit inflammation. However, the anticancer mechanisms and molecular targets of ARC and PML are poorly understood, particularly in epidermal growth factor (EGF)-induced neoplastic cell transformation. The aim of this study was to evaluate the chemopreventive effects and mechanisms of the methanol extracts from ARC (MARC) and PML (MPML) in EGF-induced neoplastic cell transformation of JB6 P+ mouse epidermal cells using an MTS assay, anchorage-independent cell transformation assay and western blotting. Our results showed that MARC and MPML significantly suppressed neoplastic cell transformation by inhibiting the kinase activity of the EGF receptor (EGFR). The activation of EGFR by EGF was suppressed by MARC and MPML treatment in EGFR(+/+) cells, but not in EGFR(-/-) cells. In addition, MARC and MPML inhibited EGF-induced cell proliferation in EGFR-expressing murine embryonic fibroblasts (EGFR(+/+)). These results strongly indicate that EGFR targeting by MARC and MPML may be a good strategy for chemopreventive or chemotherapeutic applications.