The Antiviral Activity of Varenicline against Dengue Virus Replication during the Post-Entry Stage.

Dengue virus (DENV) poses a significant global health challenge, with millions of cases each year. Developing effective antiviral drugs against DENV remains a major hurdle. Varenicline is a medication used to aid smoking cessation, with anti-inflammatory and antioxidant effects. In this study, varenicline was investigated for its antiviral potential against DENV. This study provides evidence of the antiviral activity of varenicline against DENV, regardless of the virus serotype or cell type used. Varenicline demonstrated dose-dependent effects in reducing viral protein expression, infectivity, and virus yield in Vero and A549 cells infected with DENV-1 and DENV-2, with EC50 values ranging from 0.44 to 1.66 µM. Time-of-addition and removal experiments demonstrated that varenicline had a stronger inhibitory effect on the post-entry stage of DENV-2 replication than on the entry stage, as well as the preinfection and virus attachment stages. Furthermore, cell-based trans-cleavage assays indicated that varenicline dose-dependently inhibited the proteolytic activity of DENV-2 NS2B-NS3 protease. Docking models revealed the formation of hydrogen bonds and van der Waals forces between varenicline and specific residues in the DENV-1 and DENV-2 NS2B-NS3 proteases. These results highlight the antiviral activity and potential mechanism of varenicline against DENV, offering valuable insights for further research and development in the treatment of DENV infection.

Correction: Aloe-emodin inhibits HER-2 expression through the downregulation of Y-box binding protein-1 in HER-2-overexpressing human breast cancer cells.

[This corrects the article DOI: 10.18632/oncotarget.10410.].

Citronellol Induces Necroptosis of Human Lung Cancer Cells via TNF-α Pathway and Reactive Oxygen Species Accumulation.

BACKGROUND/AIM: Our current study aimed to determine the molecular mechanisms of citronellol-induced cell death and ROS accumulation in non-small cell lung cancer (NCI-H1299 cells) and also compare the anticancer effects of citronellol and EOPC. MATERIALS AND METHODS: ROS measurement and western blotting were performed to detect whether citronellol can induce necroptosis in vitro. Besides, we performed an in vivo analysis of tumourigenesis inhibition by citronellol treatment in BALB/c (nu/nu) nude mice. RESULTS: Necroptosis occured by up-regulating TNF-α, RIP1/RIP3 activities, and down-regulating caspase-3/caspase-8 activities after citronellol treatment in NCI-H1299 cells. Citronellol also resulted in a biphasic increase in ROS production at 1 h and at 12 h in NCI-H1299 cells. Xenograft model experiments showed that citronellol could effectively inhibit subcutaneous tumours produced 4 weeks after intraperitoneal injection of NCI-H1299 in BALB/c nude mice. CONCLUSION: Citronellol induced necroptosis of NCI-H1299 cells via TNF-α pathway and ROS accumulation.

Curcumin Promotes Connexin 43 Degradation and Temozolomide-Induced Apoptosis in Glioblastoma Cells.

Glioblastoma (GBM) is the most commonly occurring tumor in the cerebral hemispheres. Currently, temozolomide (TMZ), an alkylating agent that induces DNA strand breaks, is considered the frontline chemotherapeutic agent for GBM. Despite its frontline status, GBM patients commonly exhibit resistance to TMZ treatment. We have recently established and characterized TMZ-resistant human glioma cells. The aim of this study is to investigate whether curcumin modulates cell apoptosis through the alternation of the connexin 43 (Cx43) protein level in TMZ-resistant GBM. Overexpression of Cx43, but not ATP-binding cassette transporters (ABC transporters), was observed (approximately 2.2-fold) in TMZ-resistant GBM cells compared to the Cx43 levels in parental GBM cells. Furthermore, at a concentration of 10 µ M, curcumin significantly reduced Cx43 protein expression by about 40%. In addition, curcumin did not affect the expression of other connexins like Cx26 or epithelial-to-mesenchymal transition (EMT) proteins such as ß -catenin or α E-catenin. Curcumin treatment led to an increase in TMZ-induced cell apoptosis from 4% to 8%. Importantly, it did not affect the mRNA expression level of Cx43. Concomitant treatment with the translation inhibitor cycloheximide (CHX) exerted additional effects on Cx43 degradation. Treatment with the autophagy inhibitor 3-MA (methyladenine) did not affect the curcumin-induced Cx43 degradation. Interestingly, treatment with the proteasome inhibitor MG132 (carbobenzoxy-Leu-Leu-leucinal) significantly negated the curcumin-induced Cx43 degradation, which suggests that curcumin-induced Cx43 degradation occurs through the ubiquitin-proteasome pathway.

Efficacy and Safety Evaluation of a Chlorine Dioxide Solution.

In this study, a chlorine dioxide solution (UC-1) composed of chlorine dioxide was produced using an electrolytic method and subsequently purified using a membrane. UC-1 was determined to contain 2000 ppm of gaseous chlorine dioxide in water. The efficacy and safety of UC-1 were evaluated. The antimicrobial activity was more than 98.2% reduction when UC-1 concentrations were 5 and 20 ppm for bacteria and fungi, respectively. The half maximal inhibitory concentrations (IC50) of H1N1, influenza virus B/TW/71718/04, and EV71 were 84.65 ± 0.64, 95.91 ± 11.61, and 46.39 ± 1.97 ppm, respectively. A 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test revealed that the cell viability of mouse lung fibroblast L929 cells was 93.7% at a 200 ppm UC-1 concentration that is over that anticipated in routine use. Moreover, 50 ppm UC-1 showed no significant symptoms in a rabbit ocular irritation test. In an inhalation toxicity test, treatment with 20 ppm UC-1 for 24 h showed no abnormality and no mortality in clinical symptoms and normal functioning of the lung and other organs. A ClO2 concentration of up to 40 ppm in drinking water did not show any toxicity in a subchronic oral toxicity test. Herein, UC-1 showed favorable disinfection activity and a higher safety profile tendency than in previous reports.

Aloe-emodin inhibits HER-2 expression through the downregulation of Y-box binding protein-1 in HER-2-overexpressing human breast cancer cells.

Human epidermal growth factor receptor-2 (HER-2)-positive breast cancer tends to be aggressive, highly metastatic, and drug resistant and spreads rapidly. Studies have indicated that emodin inhibits HER-2 expression. This study compared the HER-2-inhibitory effects of two compounds extracted from rhubarb roots: aloe-emodin (AE) and rhein. Our results indicated that AE exerted the most potent inhibitory effect on HER-2 expression. Treatment of HER-2-overexpressing breast cancer cells with AE reduced tumor initiation, cell migration, and cell invasion. AE was able to suppress YB-1 expression, further suppressing downstream HER-2 expression. AE suppressed YB-1 expression through the inhibition of Twist in HER-2-overexpressing breast cancer cells. Our data also found that AE inhibited cancer metastasis and cancer stem cells through the inhibition of EMT. Interestingly, AE suppressed YB-1 expression through the downregulation of the intracellular integrin-linked kinase (ILK)/protein kinase B (Akt)/mTOR signaling pathway in HER-2-overexpressing breast cancer cells. In vivo study showed the positive result of antitumor activity of AE in nude mice injected with human HER-2-overexpressing breast cancer cells. These findings suggest the possible application of AE in the treatment of HER-2-positive breast cancer.

Quantitative phosphoproteomic analysis reveals γ-bisabolene inducing p53-mediated apoptosis of human oral squamous cell carcinoma via HDAC2 inhibition and ERK1/2 activation.

γ-Bisabolene, one of main components in cardamom, showed potent in vitro and in vivo anti-proliferative activities against human oral squamous cell carcinoma (OSCC). γ-Bisabolene activated caspases-3/9 and decreased mitochondrial memebrane potential, leading to apoptosis of OSCC cell lines (Ca9-22 and SAS), but not normal oral fibroblast cells. Phosphoproteome profiling of OSCC cells treated with γ-bisabolene was identified using TiO2-PDMS plate and LC-MS/MS, then confirmed using Western blotting and real-time RT-PCR assays. Phosphoproteome profiling revealed that γ-bisabolene increased the phosphorylation of ERK1/2, protein phosphatases 1 (PP1), and p53, as well as decreased the phosphorylation of histone deacetylase 2 (HDAC2) in the process of apoptosis induction. Protein-protein interaction network analysis proposed the involvement of PP1-HDAC2-p53 and ERK1/2-p53 pathways in γ-bisabolene-induced apoptosis. Subsequent assays indicated γ-bisabolene eliciting p53 acetylation that enhanced the expression of p53-regulated apoptotic genes. PP1 inhibitor-2 restored the status of HDAC2 phosphorylation, reducing p53 acetylation and PUMA mRNA expression in γ-bisabolene-treated Ca9-22 and SAS cells. Meanwhile, MEK and ERK inhibitors significantly decreased γ-bisabolene-induced PUMA expression in both cancer cell lines. Notably, the results ascertained the involvement of PP1-HDAC2-p53 and ERK1/2-p53 pathways in mitochondria-mediated apoptosis of γ-bisabolene-treated cells. This study demonstrated γ-bisabolene displaying potent anti-proliferative and apoptosis-inducing activities against OSCC in vitro and in vivo, elucidating molecular mechanisms of γ-bisabolene-induced apoptosis. The novel insight could be useful for developing anti-cancer drugs.

Penta-O-galloyl-ß-D-glucose suppresses EGF-induced eIF3i expression through inhibition of the PI3K/AKT/mTOR pathway in prostate cancer cells.

Approximately 70% of prostate cancer patients will develop bone metastasis in axial and other regions of the skeleton. Epidermal growth factor (EGF) generated from bone tissue contributes to prostate cancer metastasis. In a previous study, penta-O-galloyl-ß-D-glucose (PGG) suppressed androgen-independent prostate cancer bone metastasis by transcriptionally repressing EGF-induced MMP-9 expression. This study utilized proteomics to analyze the effects of PGG in EGF-induced prostate cancer bone metastasis. This study showed that PGG suppressed EGF-induced eIF3i expression in PC-3 cells. By transfection of eIF3i shRNA, it was observed that reduced eIF3i expression suppressed the invasion of PC-3 cells in vitro. PGG reduced EGF-induced eIF3i expression through inhibition of the PI3K/AKT/mTOR pathway. Therefore, PGG may be able to be used as a potential new therapeutic drug for prostate cancer bone metastasis.

S100A8 as potential salivary biomarker of oral squamous cell carcinoma using nanoLC-MS/MS.

BACKGROUND: Oral squamous cell carcinoma (OSCC) shows low 5-year survival; early treatment greatly reduces mortality and morbidity. Saliva is a non-invasive sample, with good potential to discover biomarkers for early detection. METHODS: NanoLC-MS/MS served to analyze saliva proteome from control subjects (n=35) and OSCC patients T1 (n=29), T2 (n=36), T3 (n=14) and T4 (n=21) stages. Identified biomarkers were verified by Western blot and ELISA assays. RESULTS: NanoLC-MS/MS analysis of salivary proteins between 10 and 15kDa identified S100A8, hemoglobin delta and gamma-G globin in T3 and T4 stage OSCC as well as S100A7 in T1 and T2 stage OSCC. Western blot and ELISA indicated positive correlation between salivary S100A8 increment and tumor size stage. High level of S100A8 appeared in 3.4, 13.9, 92.9, and 100% of saliva OSCC patients with T1, T2, T3, and T4 stages, respectively. Significant increase of salivary S100A7 was observed in 20.7% and 11.1% of those with T1 and T2, respectively. AUROC curve indicated high sensitivity, specificity and accuracy of S100A8-based ELISA as a detector. CONCLUSIONS: NanoLC-MS/MS, Western blot and ELISA manifested salivary S100A8 as a specific and sensitive marker for detection of OSCC patients. Salivary S100A8 protein could be applicable in developing OSCC diagnostics.

Osthole inhibits insulin-like growth factor-1-induced epithelial to mesenchymal transition via the inhibition of PI3K/Akt signaling pathway in human brain cancer cells.

Glioblastoma multiforme (GBM) is one of the most lethal types of tumors and highly metastatic and invasive. The epithelial-to-mesenchymal transition (EMT) is the crucial step for cancer cells to initiate the metastasis and could be induced by many growth factors. In this study, we found that GBM8401 cells were converted to fibroblastic phenotype and the space between the cells became expanded in response to insulin-like growth factor-1 (IGF-1) treatment. Epithelial markers were downregulated and mesenchymal markers were upregulated simultaneously after IGF-1 treatment. Our results illustrate that IGF-1 was able to induce EMT in GBM8401 cells. Osthole would reverse IGF-1-induced morphological changes, upregulated the expression of epithelial markers, and downregulated the expression of mesenchymal markers. Moreover, wound-healing assay also showed that osthole could inhibit IGF-1-induced migration of GBM8401 cells. By using dual-luciferase reporter assay and real-time PCR, we demonstrated that osthole inhibited IGF-1-induced EMT at the transcriptional level. Our study found that osthole decreased the phosphorylation of Akt and GSK3ß and recovered the GSK3ß bioactivity in inhibiting EMT transcription factor Snail and Twist expression. These results showed that osthole inhibited IGF-1-induced EMT by blocking PI3K/Akt pathway. We hope that osthole can be used in anticancer therapy and be a new therapeutic medicine for GBM in the future.

Chemical constituents and anticancer activity of Curcuma zedoaria roscoe essential oil against non-small cell lung carcinoma cells in vitro and in vivo.

In this study, we report that the essential oil obtained from Curcuma zedoaria Roscoe, known as zedoary, possesses efficient cytotoxic effects on non-small cell lung carcinoma (NSCLC) cells and causes cell apoptosis. Zedoary essential oil increased the sub-G1 population and the level of annexin-V binding and induced cleavage and activation of caspase-3, -8, and -9 and poly(ADP ribose) polymerase. Decreases in the levels of Bcl-2 and Bcl-xL and an increase in the Bax/Bcl-2 ratio were also observed following zedoary essential oil treatment. Notably, zedoary essential oil led to the release of AIF, endonuclease G, and cytochrome c into the cytosol and increased levels of p53 in H1299 cells. Our results indicate that zedoary essential oil slightly inhibited the phosphorylation of ERK1/2 and enhanced the phosphorylation of JNK1/2 and p38. Zedoary essential oil also inhibited AKT/NF-κB signaling pathways in H1299 cells. Moreover, intraperitoneal administration of zedoary essential oil significantly suppressed the growth of H1299 cells in vivo. In addition, potential active compounds were detected using gas chromatography and mass spectrometry. 8,9-Dehydro-9-formyl-cycloisolongifolene, 6-ethenyl-4,5,6,7-tetrahydro-3,6-dimethyl-5-isopropenyl-trans-benzofuran, eucalyptol, and γ-elemene were found in zedoary essential oil. In summary, our findings provide insight into the molecular mechanisms underlying zedoary essential oil-induced apoptosis in NSCLC cells that are worthy of further study.

EGCG inhibits transforming growth factor-ß-mediated epithelial-to-mesenchymal transition via the inhibition of Smad2 and Erk1/2 signaling pathways in nonsmall cell lung cancer cells.

Transforming growth factor-ß (TGF-ß)-mediated epithelial mesenchymal transition (EMT) of human lung cancer cells may contribute to lung cancer metastasis. It has been reported that EGCG can inhibit tumorigenesis and cancer cell growth in lung cancer; however, the effect of EGCG on EMT in nonsmall cell lung cancer (NSCLC) cells has not been investigated. In this study, we found that NSCLC cells A549 and H1299 were converted to the fibroblastic phenotype in response to TGF-ß. Epithelial marker E-cadherin was down-regulated, and mesenchymal marker vimentin was up-regulated simultaneously. Our results illustrated that TGF-ß was able to induce EMT in NSCLC cells, and EGCG would reverse TGF-ß-induced morphological changes, up-regulate the expression of E-cadherin, and down-regulate the expression of vimentin. Immunofluorescent staining also demonstrated that E-cadherin was up-regulated and that vimentin was down-regulated by EGCG pretreatment. Moreover, wound-healing and the in vitro invasion assay showed that EGCG could inhibit TGF-ß-induced migration and invasion of NSCLC cells. By using the dual-luciferase reporter assay, we demonstrated that EGCG inhibited TGF-ß-induced EMT at the transcriptional level. EGCG decreased the phosphorylation of Smad2 and Erk1/2, inhibited the nuclear translocation of Smad2, and repressed the expression of transcription factors ZEB1, Snail, Slug, and Twist, and up-regulated the expression of E-cadherin. In summary, our results suggest that EGCG can inhibit TGF-ß-induced EMT via down-regulation of phosphorylated Smad2 and Erk1/2 in NSCLC cells.

High yield expression in a recombinant E. coli of a codon optimized chicken anemia virus capsid protein VP1 useful for vaccine development.

BACKGROUND: Chicken anemia virus (CAV), the causative agent chicken anemia, is the only member of the genus Gyrovirus of the Circoviridae family. CAV is an immune suppressive virus and causes anemia, lymph organ atrophy and immunodeficiency. The production and biochemical characterization of VP1 protein and its use in a subunit vaccine or as part of a diagnostic kit would be useful to CAV infection prevention. RESULTS: Significantly increased expression of the recombinant full-length VP1 capsid protein from chicken anemia virus was demonstrated using an E. coli expression system. The VP1 gene was cloned into various different expression vectors and then these were expressed in a number of different E. coli strains. The expression of CAV VP1 in E. coli was significantly increased when VP1 was fused with GST protein rather than a His-tag. By optimizing the various rare amino acid codons within the N-terminus of the VP1 protein, the expression level of the VP1 protein in E. coli BL21(DE3)-pLysS was further increased significantly. The highest protein expression level obtained was 17.5 g/L per liter of bacterial culture after induction with 0.1 mM IPTG for 2 h. After purification by GST affinity chromatography, the purified full-length VP1 protein produced in this way was demonstrated to have good antigenicity and was able to be recognized by CAV-positive chicken serum in an ELISA assay. CONCLUSIONS: Purified recombinant VP1 protein with the gene's codons optimized in the N-terminal region has potential as chimeric protein that, when expressed in E. coli, may be useful in the future for the development of subunit vaccines and diagnostic tests.

Study of the Anti-Proliferative Activity of 5-Substituted 4,7-Dimethoxy-1,3-Benzodioxole Derivatives of SY-1 from Antrodia camphorata on Human COLO 205 Colon Cancer Cells.

A set of 10 4,7-dimethoxy-1,3-benzodioxole derivatives based on a lead compound previously discovered by our group, SY-1, which was isolated from Antrodia camphorata, were evaluated for their in vitro inhibitory activity on human colorectal carcinoma cells (COLO 205). Structure-activity relationship studies of the 10 compounds indicated the importance of the chain length of the alkyl group at the 5-position, and the 2-propenyl substituent named "apiole" exhibited the most potent inhibitory activity. In the present study, we demonstrate that the SY-1 analogue "apiole" decreased the proliferation of COLO 205 cells, but not that of normal human colonic epithelial cells (FHC). The G0/G1 cell cycle arrest induced by apiole (75-225 µM) was associated with significantly increased levels of p53, p21 and p27 and decreased levels of cyclin D1. Concerning COLO 205 cell apoptosis, apiole (>150 µM) treatment significantly increased the levels of cleaved caspases 3, 8, 9 and bax/bcl-2 ratio and induced ladder formation in DNA fragmentation assay and sub-G1 peak in flow cytometry analysis. These findings suggest that apiole can suppress COLO 205 cell growth; however, the detailed mechanisms of these processes require further investigation.

Salivary zinc finger protein 510 peptide as a novel biomarker for detection of oral squamous cell carcinoma in early stages.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is one of the most frequent malignancies worldwide. Early diagnosis can mean adequate treatment and increase survival. METHODS: This study uses ClinProt technique to identify salivary biomarkers for early diagnosis of OSCC. A total of 77 salivary samples from both OSCC patients (n=47) and healthy donors (n=30) were analyzed with MALDI-TOF MS technology. RESULTS: Salivary peptides from OSCC patients were separated, using C8-functionalized magnetic beads. Three signals (2918.57 Da, 5592.64 Da, and 4372.66 Da) distinguished OSCC patients from controls. Among them, unique peptide 2918.57 Da, identified as a 24-mer peptide of zinc finger protein 510 (ZNF510), was found in 0% of saliva from healthy individuals, versus 25.0% and 60% from OSCC patients with T1+T2 and T3+T4 stages, respectively (P<0.001). ELISA analysis with rabbit anti-ZNF510 peptide sera shows a starkly higher 24-mer ZNF510 peptide level in saliva from OSCC patients than that in controls (P<0.001). Also, in immunohistochemical analysis of oral tissues, a significantly higher level of ZNF510 was observed in OSCC tissues than in the OSCC free control tissues. Analysis of areas under receiver-operating characteristic (ROC) curves in OSCC early (T1+T2) and late stages (T3+T4) shows greater than 0.95. CONCLUSIONS: Identifying 24-mer ZNF510 peptide as OSCC-related salivary biomarkers via proteomic approach proved useful in adjunct diagnosis for early detection rather than specific diagnosis marker for progression of OSCC patients.

Antifatigue and Antioxidant Activity of Alcoholic Extract from Saussurea involucrata.

Fatigue is a noticeable and highly prevalent symptom in tense, industriously, and economically affluent modern society. Therefore, new antifatigue agents to smooth the fatigue feature are an energetic topic. The total ethanol extract (ESI) of Saussurea involucrata Kar et Kir., known as Tian-Shan snow lotus, was evaluated for antifatigue activity in ICR mice with mice forced swimming test and the determination of the contents of blood lactic acid and serum urea nitrogen. ESI (0.05, 0.15, 0.25 g/kg) was administered orally to mice for 4 weeks. The average swimming times to exhaustion of the ESI-treated ICR mice (0.15, 0.25 g/kg) were prolonged by 132% and 180% (p<0.001) with a lessening of fatigue compared with that of the control group. Analysis of biochemical parameters showed that levels of serum urea nitrogen and blood lactic acid of experimental groups were also decreased significantly (p<0.001) compared with that of the control group. The antioxidant activity of ESI was investigated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assay and the hydrogen peroxide-induced luminol chemiluminescence assay and the results indicated that ESI exerts DPPH scavenging ability and reducing power. These results provide scientific evidence that S. involucrata may have been potential as an antifatigue agent.

Proteomic identification of salivary transferrin as a biomarker for early detection of oral cancer.

Oral cancer has a low five-year survival rate. Early detection of oral cancer could reduce the mortality and morbidity associated with this disease. Saliva, which can be sampled non-invasively and is less complex than blood, is a good potential source of oral cancer biomarkers. Proteomic analysis of saliva from oral cancer patients and control subjects was performed to identify salivary biomarkers of early stage oral cancer in humans. The protein profile of pooled salivary samples from patients with oral squamous cell carcinoma (OSCC) or OSCC-free control subjects was analyzed using two-dimensional gel electrophoresis (2DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analyses. Potential biomarkers were verified by Western blotting and ELISA assays. Transferrin levels were elevated in the saliva of OSCC patients as determined using 2DE followed by MALDI-TOF MS and confirmed by MALDI-TOF/TOF MS, Western blotting and ELISA. The increase in salivary transferrin levels in OSCC patients strongly correlated with the size and stage of the tumor. The area under the receiver-operating characteristics curves showed that salivary transferrin-based ELISA was highly specific, sensitive and accurate for the early detection of oral cancer. We have identified salivary transferrin as a biomarker for the detection of early stage oral cancer. This finding provides a promising basis for the development of a non-invasive diagnostic test for early stage oral cancer.

Regulation of excision repair cross-complementation group 1 by Snail contributes to cisplatin resistance in head and neck cancer.

PURPOSE: We investigated the mechanism and clinical significance of the epithelial-mesenchymal transition (EMT)-induced chemoresistance in head and neck squamous cell carcinoma (HNSCC). EXPERIMENTAL DESIGN: The correlation between the expression of different EMT regulators and chemoresistance genes, such as excision repair cross complementation group 1 (ERCC1), was evaluated in cancer cell lines from the NCI-60 database and four human HNSCC cell lines. Ectopic expression of Snail or short-interference RNA-mediated repression of Snail or ERCC1 was done in HNSCC cell lines. Cell viability was examined for cells after cisplatin treatment. A luciferase reporter assay and chromatin immunoprecipitation were used to identify the transcriptional regulation of ERCC1 by Snail. Immunohistochemical analysis of Snail, Twist1, ERCC1, hypoxia inducible factor-1 α (HIF-1α), and NBS1 were done in samples from 72 HNSCC patients receiving cisplatin-based chemotherapy. RESULTS: The correlation between the expression of Snail and ERCC1 was confirmed in different cell lines, including HNSCC cells. In HNSCC cell lines, overexpression of Snail in the low endogenous Snail/ERCC1 cell lines FaDu or CAL-27 increased ERCC1 expression, and hypoxia or overexpression of NBS1 also upregulated ERCC1. Knockdown of Snail in the high endogenous Snail/ERCC1 cell line OECM-1 downregulated ERCC1 expression and attenuated cisplatin resistance. Furthermore, suppression of ERCC1 in Snail- or NBS1-overexpressing HNSCC cells enhanced sensitivity to cisplatin. Snail directly regulated ERCC1 transcription. In patients with HNSCC, coexpression of Snail and ERCC1 correlated with cisplatin resistance and a poor prognosis. CONCLUSIONS: Activation of ERCC1 by Snail is critical in the generation of cisplatin resistance of HNSCC cells.

Hispidulin potently inhibits human glioblastoma multiforme cells through activation of AMP-activated protein kinase (AMPK).

Glioblastoma multiforme (GBM) is the most common and lethal type of primary brain tumor. Despite recent therapeutic advances in other cancers, the treatment of GBM remains ineffective and essentially palliative. The current focus lies in the finding of components that activate the AMP-activated protein kinase (AMPK), one key enzyme thought to be activated during the caloric restriction (CR). In the present study, we found that treatment of hispidulin, a flavone isolated from Saussurea involucrate Kar. et Kir., resulted in dose-dependent inhibition of GBM cellular proliferation. Interestingly, we show that hispidulin activated AMPK in GBM cells. The activation of AMPK suppressed downstream substrates, such as the mammalian target of rapamycin (mTOR) and eukaryotic initiation factor 4E-binding protein-1 (4E-BP1), and resulted in a general decrease in mRNA translation. Moreover, hispidulin-activated AMPK decreases the activity and/or expression of lipogenic enzymes, such as fatty acid synthase (FASN) and acetyl-CoA carboxylase (ACC). Furthermore, hispidulin blocked the progression of the cell cycle at the G1 phase and induced apoptosis by inducing p53 expression and further upregulating p21 expression in GBM cells. On the basis of these results, we demonstrated that hispidulin has the potential to be a chemopreventive and therapeutic agent against human GBM.

Hispidulin sensitizes human ovarian cancer cells to TRAIL-induced apoptosis by AMPK activation leading to Mcl-1 block in translation.

Whether hispidulin, a flavone from traditional Chinese medicine, can modulate the anticancer effects of the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), the cytokine currently in clinical trials was investigated. In the present study, we found that hispidulin potentiated the TRAIL-induced apoptosis in human ovarian cancer cells and converted TRAIL-resistant cells to TRAIL-sensitive cells. When examined for its mechanism, we found that hispidulin was highly effective in activation of caspases 8 and caspase 3 and consequent poly(ADP-ribose) polymerase (PARP) cleavage. Moreover, we found that hispidulin downregulated the expression of Mcl-1, Bcl-2, and Bcl-xL. Whereas the downregulation of Bcl-2 and Bcl-xL was less pronounced, the downregulation of Mcl-1 was quite dramatic and was time-dependent. This sensitization is controlled through the adenosine monophosphate (AMP)-activated protein kinase (AMPK), which is the central energy-sensing system of the cell. Interestingly, we determined that AMPK is activated upon hispidulin treatment, resulting in mammalian target of rapamycin (mTOR) inhibition leading to Mcl-1 decrease. Therefore, our results show a novel mechanism for the sensitization to TRAIL-induced apoptosis linking hispidulin treatment to Mcl-1 downexpression. In addition, this study provides a rationale for the combined use of death receptor (DR) ligands with AMPK activators or mTOR inhibitors in the treatment of human cancers.