Metformin induces autophagy of cisplatin-resistant human gastric cancer cells in addition to apoptosis.

Metformin has been used to treat cases of type 2 diabetes mellitus, and mounting studies have shown that metformin can act alone or in synergy with other anticancer agents to achieve anti-cancer efficacies on various types of tumors. However, the role of metformin in either inducing autophagy and cisplatin-resistance of human gastric cancer (GC) cells has never been examined. The study has established a cisplatin-resistant GC cell line and investigated the effects of metformin on inducing autophagy on it. The results demonstrated that treatment with metformin can concentration-dependently suppress the cell viability and cell confluence of cisplatin-resistant GC cells, while having no effects on human primary stomach epithelial cells (HPSEC). For the first time, we found that metformin can significantly increase the acidic vesicular organelles (AVO) level and decrease the acridine orange (AO) level spontaneously in the cisplatin-resistant GC cells. Thus, we further checked the other markers, Atg5, Atg12 and LC3-II, which showed that metformin indeed induced autophagy in the cisplatin-resistant GC cells. In addition, treatment of 3-Methyladenine (3-MA) can significantly rescue the metformin-induced autophagy. At the same time, metformin can induce the alterations of apoptosis-associated signal molecules, such as caspase-3 and caspase-7 activities. Overall, the pilot study provided evidence for metformin induced autophagy in addition to apoptosis, making it as an effective anticancer drug for the therapy of cisplatin-resistant GC. Killing the cisplatin-resistant GC cells with non-toxic metformin via both autophagy and apoptosis might extend its usefulness in our fighting with chemo-resistance of gastric cancer cells.

Efficacy of HMJ-38, a new quinazolinone analogue, against the gemcitabine-resistant MIA-PaCa-2 pancreatic cancer cells.

Gemcitabine is frequently utilized to treat pancreatic cancer. The purpose of our study was to create a gemcitabine-resistant MIA-PaCa-2 pancreatic cancer cell line (MIA-GR100) and to evaluate the anti-pancreatic cancer efficacy of HMJ-38, a new quinazolinone analogue. Compared to their parental counterparts, MIA-PaCa-2, established MIA-GR100 cells were less sensitive to gemcitabine. MIA-GR100 cell viability was not affected by 10, 50 and 100 nM gemcitabine concentrations. HMJ-38 reduced MIA-GR100 cell growth and induced autophagy and apoptosis. When stained with monodansylcadaverine (MDC), acridine orange (AO), and terminal deoxynucleotide transferase dUTP nick end labeling (TUNEL), MIA-GR100 cells shrunk, punctured their membranes, and produced autophagy vacuoles and apoptotic bodies. Combining chloroquine (CQ) and 3-methyladenine (3-MA) with HMJ-38 dramatically reduced cell viability, indicating that autophagy function as a cytoprotective mechanism. MIA-GR100 cells treated with both z-VAD-FMK and HMJ-38 were much more viable than those treated with HMJ-38 alone. HMJ-38 promotes apoptosis in MIA-GR100 cells by activating caspases. Epidermal growth factor receptor (EGFR) is one of HMJ-38's principal targets, as determined via in silico target screening with network prediction. HMJ-38 also inhibited EGFR kinase activity and EGFR-associated signaling in MIA-GR100 cells. HMJ-38 may be an effective chemotherapeutic adjuvant for gemcitabine-resistant pancreatic cancer cells, in which it induces an antitumor response.

Tremella fuciformis Inhibits Melanogenesis in B16F10 Cells and Promotes Migration of Human Fibroblasts and Keratinocytes.

BACKGROUND/AIM: Natural skin whiteners have been investigated for centuries. The development of preparations that safely achieve whitening of hyper-pigmented skin lesions is a challenge for the cosmetics industry. Furthermore, promoting rapid wound healing and minimizing inflammation in injured skin are key to prevent from abnormal pigmentation in scar tissue. Natural products, including the fungus Tremella fuciformis (TF), are attracting attention as potential sources of lead compounds for these applications. MATERIALS AND METHODS: We investigated the in vitro effects of TF on melanogenesis in murine B16F10 cells. Melanin and tyrosinase levels were measured after treatment with TF. Wound healing in human keratinocytes (HaCaT) and fibroblasts (Detroit 551) was also determined via cell migration assay prior to TF exposure. RESULTS: TF significantly decreased melanin content and tyrosinase expression in a concentration-dependent manner in B16F10 cells. Furthermore, TF promoted wound healing in human HaCaT keratinocytes and Detroit 551 fibroblasts. CONCLUSION: TF proved effectively on inhibiting melanogenesis and promoting wound healing in vitro, demonstrating its potential as a novel skin-whitening agent. However, further clinical studies of safety and efficacy are required.

Curcumin suppresses cell proliferation and triggers apoptosis in vemurafenib-resistant melanoma cells by downregulating the EGFR signaling pathway.

Melanoma is a malignant tumor with aggressive behavior. Vemurafenib, a BRAF inhibitor, is clinically used in melanoma, but resistance to melanoma cytotoxic therapies is associated with BRAF mutations. Curcumin can effectively inhibit numerous types of cancers. However, there are no reports regarding the correlation between curcumin and vemurafenib-resistant melanoma cells. In this study, vemurafenib-resistant A375.S2 (A375.S2/VR) cells were established, and the functional mechanism of the epidermal growth factor receptor (EGFR), serine-threonine kinase (AKT), and the extracellular signal-regulated kinase (ERK) signaling induced by curcumin was investigated in A375.S2/VR cells in vitro. Our results indicated that A375.S2/VR cells had a higher IC50 concentration of vemurafenib than the parental A375.S2 cells. Moreover, curcumin reduced the viability and confluence of A375.S2/VR cells. Curcumin triggered apoptosis via reactive oxygen species (ROS) production, disruption of mitochondrial membrane potential (ΔΨm), and intrinsic signaling (caspase-9/-3-dependent) pathways in A375.S2/VR cells. Curcumin-induced apoptosis was also mediated by the EGFR signaling pathway. Combination treatment with curcumin and gefitinib (an EGFR inhibitor) synergistically potentiated the inhibitory effect of cell viability in A375.S2/VR cells. The present study provides new insights into the therapy of vemurafenib-resistant melanoma and suggests that curcumin might be an encouraging therapeutic candidate for its drug-resistant treatment.

Novel quinazolinone MJ­33 induces AKT/mTOR­mediated autophagy­associated apoptosis in 5FU­resistant colorectal cancer cells.

Novel quinazolinone compounds have been studied in the field of drug discovery for a long time. Among their broad range of pharmacological effects, certain compounds effectively inhibit cancer cell proliferation. MJ­33 is a quinazolinone derivative with proposed anticancer activities that was synthesized in our laboratory. The present study aimed to evaluate the anticancer activity of MJ­33 in fluorouracil (5FU)­resistant colorectal cancer cells (HT­29/5FUR) and to investigate the underlying molecular mechanisms. The cell viability assay results indicated that HT­29/5FUR cell viability was inhibited by MJ­33 treatment in a concentration­dependent manner compared with the control group. The cellular morphological alterations observed following MJ­33 treatment indicated the occurrence of apoptosis and autophagy, as well as inhibition of cell proliferation in a time­dependent manner compared with the control group. The acridine orange, LysoTracker Red and LC3­green fluorescent protein staining results indicated that MJ­33 treatment significantly induced autophagy compared with the control group. The DAPI/TUNEL dual staining results demonstrated increased nuclear fragmentation and condensation following MJ­33 treatment compared with the control group. The Annexin V apoptosis assay and image cytometry analysis results demonstrated a significant increase in apoptotic cells following MJ­33 treatment compared with the control group. The western blotting results demonstrated markedly decreased Bcl­2, phosphorylated (p)­BAD, pro­caspase­9 and pro­caspase­3 expression levels, and notably increased cytochrome c and apoptotic peptidase activating factor 1 expression levels following MJ­33 treatment compared with the control group. Moreover, the expression levels of autophagy­related proteins, including autophagy related (ATG)­5, ATG­7, ATG­12, ATG­16, p62 and LC3­II, were increased following MJ­33 treatment compared with the control group. Furthermore, MJ­33­treated HT­29/5FUR cells displayed decreased expression levels of p­AKT and p­mTOR compared with control cells. The results suggested that MJ­33­induced apoptosis was mediated by AKT signaling, and subsequently modulated via the mitochondria­dependent signaling pathway. Therefore, the results suggested that suppression of AKT/mTOR activity triggered autophagy in the HT­29/5FUR cell line. In summary, the results indicated that MJ­33 inhibited HT­29/5FUR cell viability, and induced apoptosis and autophagy via the AKT/mTOR signaling pathway. The present study may provide novel insight into the anticancer effects and mechanisms underlying MJ­33 in 5FU­resistant colorectal cancer cells.

Analysis of COVID-19 prevention and treatment in Taiwan.

Coronavirus disease 2019 (COVID-19) has been spreading worldwide with a mind-boggling speed. According to a statement from World Health Organization (WHO), COVID-19 has infected more than six billions people and caused more than one and half million passing in the world. Based on previous experience with SARS, the Taiwanese government had decided to block viral transmission during its early stages. This review sums up the clinical characteristics, Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) viral infection process, diagnostic methods, preventive strategy, and the executive proportions of COVID-19, as well as the name-based mask distribution system (NBMDS) in Taiwan. We also give a review of the conceivable sub-atomic pharmacologic systems against SARS-CoV-2 specialists and the blend of remdesivir (GS-5734), chloroquine (CQ), and hydroxychloroquine (HCQ). Lastly, we summarized the therapeutic agents against COVID-19 as mentioned by COVID-19 treatment guidelines. In this review, development of novel anti-SARS-CoV-2 viral agents, vaccines for COVID-19 therapy or an effective combination therapy can be expected based on all the information accumulated. Last but not least, we might want to stretch out our best respects to all medical providers in their worldwide battle against COVID-19.

Sensitivity of allyl isothiocyanate to induce apoptosis via ER stress and the mitochondrial pathway upon ROS production in colorectal adenocarcinoma cells.

Allyl isothiocyanate (AITC), a bioactive phytochemical compound that is a constituent of dietary cruciferous vegetables, possesses promising chemopreventive and anticancer effects. However, reports of AITC exerting antitumor effects on apoptosis induction of colorectal cancer (CRC) cells in vitro are not well elucidated. The present study focused on the functional mechanism of the endoplasmic reticulum (ER) stress­based apoptotic machinery induced by AITC in human colorectal cancer HT­29 cells. Our results indicated that AITC decreased cell growth and number, reduced viability, and facilitated morphological changes of apoptotic cell death. DNA analysis by flow cytometry showed G2/M phase arrest, and alterations in the modulated protein levels caused by AITC were detected via western blot analysis. AITC also triggered vital intrinsic apoptotic factors (caspase­9/caspase­3 activity), disrupted mitochondrial membrane potential, and stimulated mitochondrial­related apoptotic molecules (e.g., cytochrome c, apoptotic protease activating factor 1, apoptosis­inducing factor, and endonuclease G). Additionally, AITC prompted induced cytosolic Ca2+ release and Ca2+­dependent ER stress­related signals, such as calpain 1, activating transcription factor 6α, glucose­regulated proteins 78 and 94, growth arrest­ and DNA damage­inducible protein 153 (GADD153), and caspase­4. The level of reactive oxygen species (ROS) production was found to induce the hallmark of ER stress GADD153, proapoptotic marker caspase­3, and calpain activity after AITC treatment. Our findings showed for the first time that AITC induced G2/M phase arrest and apoptotic death via ROS­based ER stress and the intrinsic pathway (mitochondrial­dependent) in HT­29 cells. Overall, AITC may exert an epigenetic effect and is a potential bioactive compound for CRC treatment.

Metformin triggers the intrinsic apoptotic response in human AGS gastric adenocarcinoma cells by activating AMPK and suppressing mTOR/AKT signaling.

Metformin is commonly used to treat patients with type 2 diabetes and is associated with a decreased risk of cancer. Previous studies have demonstrated that metformin can act alone or in synergy with certain anticancer agents to achieve anti­neoplastic effects on various types of tumors via adenosine monophosphate­activated protein kinase (AMPK) signaling. However, the role of metformin in AMPK­mediated apoptosis of human gastric cancer cells is poorly understood. In the current study, metformin exhibited a potent anti­proliferative effect and induced apoptotic characteristics in human AGS gastric adenocarcinoma cells, as demonstrated by MTT assay, morphological observation method, terminal deoxynucleotidyl transferase dUTP nick end labeling and caspase­3/7 assay kits. Western blot analysis demonstrated that treatment with metformin increased the phosphorylation of AMPK, and decreased the phosphorylation of AKT, mTOR and p70S6k. Compound C (an AMPK inhibitor) suppressed AMPK phosphorylation and significantly abrogated the effects of metformin on AGS cell viability. Metformin also reduced the phosphorylation of mitogen­activated protein kinases (ERK, JNK and p38). Additionally, metformin significantly increased the cellular ROS level and included loss of mitochondrial membrane potential (ΔΨm). Metformin altered apoptosis­associated signaling to downregulate the BAD phosphorylation and Bcl­2, pro­caspase­9, pro­caspase­3 and pro­caspase­7 expression, and to upregulate BAD, cytochrome c, and Apaf­1 proteins levels in AGS cells. Furthermore, z­VAD­fmk (a pan­caspase inhibitor) was used to assess mitochondria­mediated caspase­dependent apoptosis in metformin­treated AGS cells. The findings demonstrated that metformin induced AMPK­mediated apoptosis, making it appealing for development as a novel anticancer drug for the treating gastric cancer.

Autophagy and apoptotic machinery caused by Polygonum cuspidatum extract in cisplatin­resistant human oral cancer CAR cells.

Polygonum cuspidatum (Hu Zhang) is a traditional Chinese medicine (TCM) and has been revealed to exert anticancer, anti­angiogenesis, anti­human immunodeficiency virus (HIV), anti­hepatitis B virus, anti­microbial, anti­inflammatory, and neuro­protective bio­activities. However, the effect of P. cuspidatum extract (PCE) on drug­resistant human oral cancer cells regarding cell death is not fully understood yet. The present study was undertaken to explore the induction of autophagic and apoptotic cell death and to investigate their underlying molecular mechanisms in PCE­treated cisplatin­resistant human oral cancer CAR cells. Our results revealed that PCE was determined via HPLC analytic method, and it was revealed that resveratrol may be a major compound in PCE. The data also demonstrated that PCE reduced CAR cell viability in a concentration­ and time­dependent response via an MTT assay. PCE had an extremely low toxicity in human normal gingival fibroblasts (HGF). Autophagic and apoptotic cell death was found after PCE treatment by morphological determination. PCE was revealed to induce autophagy as determined using acridine orange (AO), LC3­GFP, monodansylcadaverine (MDC) and LysoTracker Red staining in CAR cells. In addition, PCE was revealed to induce apoptosis in CAR cells via 4',6­diamidino­2­phenylindole (DAPI)/terminal deoxynucleotidyl transferase dUTP nick­end labeling (TUNEL) double staining. PCE significantly stimulated caspase­9 and ­3 activities as revealed using caspase activity assays. PCE markedly increased the protein levels of Atg5, Atg7, Atg12, Beclin­1, LC3, Bax and cleaved caspase­3, while it decreased the protein expression of Bcl­2 in CAR cells as determined by western blotting. In conclusion, our findings are the first to suggest that PCE may be potentially efficacious for the treatment of cisplatin­resistant human oral cancer.

Synergistic inhibitory effects of cetuximab and curcumin on human cisplatin-resistant oral cancer CAR cells through intrinsic apoptotic process.

Cetuximab, an epidermal growth factor receptor (EGFR)-targeting monoclonal antibody (mAb), is a novel targeted therapy for the treatment of patients with oral cancer. Cetuximab can be used in combination with chemotherapeutic agents to prolong the overall survival rates of patients with oral cancer. Curcumin is a traditional Chinese medicine, and it has been demonstrated to have growth-inhibiting effects on oral cancer cells. However, information regarding the combination of cetuximab and curcumin in drug-resistant oral cancer cells is lacking, and its underlying mechanism remains unclear. The purpose of the present study was to explore the oral anticancer effects of cetuximab combined with curcumin on cisplatin-resistant oral cancer CAR cell apoptosis in vitro. The results demonstrated that combination treatment synergistically potentiated the effect of cetuximab and curcumin on the suppression of cell viability and induction of apoptosis in CAR cells. Cetuximab and curcumin combination induced apoptosis and dramatically increased caspase-3 and caspase-9 activities compared with singular treatment. Combination treatment also markedly suppressed the protein expression levels of EGFR and mitogen-activated protein kinases (MAPKs) signaling (phosphorylation of ERK, JNK and p38). The results demonstrated that co-treatment with cetuximab and curcumin exerts synergistic oral anticancer effects on CAR cells through the suppression of the EGFR signaling by regulation of the MAPK pathway.

Ursolic acid elicits intrinsic apoptotic machinery by downregulating the phosphorylation of AKT/BAD signaling in human cisplatin­resistant oral cancer CAR cells.

Oral squamous cell carcinoma (OSCC) is a type of cancer with high morbidity and mortality rates worldwide; it also demonstrates chemotherapeutic resistance. Triterpenoid ursolic acid has been shown to exhibit various biological activities and anticancer effects in several preclinical studies. In our previous study, human cisplatin­resistant oral cancer CAR cells were established, and the present study aimed to further examine the effects of ursolic acid on CAR cells. The results revealed that ursolic acid inhibited CAR cell viability, as determined using a 3­(4,5­dimethylthiazol­2­yl)­2,5­diphenyltetrazolium bromide assay. Ursolic acid­induced cell death was mediated through a caspase­dependent pathway, determined with the pan­caspase inhibitor, z­VAD­fmk. Ursolic acid also increased the activities of caspase­3 and caspase­9 in CAR cells, determined by a colorimetric assay. Specifically, the production of reactive oxygen species and loss of mitochondrial membrane potential, detected by flow cytometry, were observed in the ursolic acid­treated CAR cells. The apoptosis­associated signaling showed that ursolic acid decreased the phosphorylation of AKT (Ser473) and B­cell lymphoma 2 (Bcl­2)­associated agonist of cell death (BAD; Ser136), and the protein levels of Bcl­2 and Bcl­extra large (Bcl­xL), and increased the expression of BAD and Bcl­2­associated X (Bax) protein in CAR cells. In summary, the results supported the potential application of ursolic acid against drug­resistant oral carcinoma and to improve oral anticancer efficacy in the near future.

cDNA Microarray Analysis and Influx Transporter OATP1B1 in Liver Cells After Exposure to Gadoxetate Disodium, a Gadolinium-based Contrast Agent in MRI Liver Imaging.

BACKGROUND/AIM: Gadoxetate disodium (Primovist or Eovist) is extensively used as a hepatospecific contrast agent during magnetic resonance imaging (MRI) examinations. However, there is no information determining whether gadoxetate disodium has a cytotoxic impact and/or affects relative gene expression on liver cells. In the current study, we investigated the effects of gadoxetate disodium on cytotoxicity and the levels of gene expression in human normal Chang Liver cells. MATERIALS AND METHODS: The cytotoxic effect was detected via methyl thiazolyl tetrazolium (MTT) assay and 4',6-diamidino-2-phenylindole (DAPI) staining. mRNA expression was monitored by cDNA microarray and quantitative PCR (qPCR) analysis. The protein levels were determined by western blotting. RESULTS: Gadoxetate disodium at 5 and 10 mM failed to induce any cell cytotoxicity and morphological changes in Chang Liver cells. Our data demonstrated that gadoxetate disodium significantly enhanced the expression of 29 genes and suppressed that of 27. The SLCO1C1 (solute carrier organic anion transporter family member 1C1) mRNA expression was also increased by 2.62-fold (p-value=0.0006) in gadoxetate disodium-treated cells. Furthermore, we also checked and found that gadoxetate disodium up-regulated organic anion transporter polypeptide 1B1 (OATP1B1) protein level and increased OATP uptake transporter gene SLCO1C1 mRNA expression. CONCLUSION: Our results provide evidence regarding that gadoxetate disodium might be no cytotoxic effects on liver cells.

Pterostilbene modulates the suppression of multidrug resistance protein 1 and triggers autophagic and apoptotic mechanisms in cisplatin-resistant human oral cancer CAR cells via AKT signaling.

Pterostilbene is a natural polyphenolic compound that is primarily found in fruits, such as blueberries and has a similar structure to resveratrol. Pterostilbene exhibits antioxidant, anti-inflammatory and antitumor activity but the effects of pterostilbene on drug-resistant oral cancer cells and its underlying mechanisms of action have not yet been explored. Therefore, the present study was performed to clarify the anticancer effects of pterostilbene on cisplatin-resistant human oral cancer CAR cells. The results demonstrated that CAR cells exhibited marked shrinkage, cell membrane breakage and autophagic vacuole formation following treatment with pterostilbene. Pterostilbene also effectively inhibited cell viability and suppressed cell confluence in a time- and concentration-dependent manner. Probing with acridine orange, monodansylcadaverine and LysoTracker Red demonstrated that the number of acidic vesicular organelles was increased, indicating increased autophagy. Furthermore, Heochst 33342 staining determined that DNA condensation, a characteristic of apoptosis, was enhanced following treatment with pterostilbene. Furthermore, pterostilbene upregulated mRNA levels of LC3-II and Atg12, as well as the expression of Atgs/Beclin-1/LC3-associated signaling, suggesting that it enhances autophagy. The autophagy inhibitors 3-methyladenine and chloroquine were used to confirm that pterostilbene induces autophagy. It was also determined that pterostilbene triggered caspase-dependent apoptosis by directly testing DNA breakage and using the pan-caspase inhibitor carbobenzoxyvalyl-alanyl-aspartyl fluoromethyl ketone. The results demonstrated that pterostilbene mediates the apoptosis of CAR cells via the intrinsic apoptotic cascade. In addition, pterostilbene inhibited MDR1 expression and the phosphorylation of AKT on the Ser473 site in CAR cells. Therefore, pterostilbene may elicit an oral anticancer response in drug-resistant cells and may be used as a chemotherapeutic adjuvant to treat patients with oral cancer.

Relaxant and vasoprotective effects of ginger extracts on porcine coronary arteries.

Ginger (Zingiber officinale Roscoe) is a popular Chinese herbal medicine, which is considered to warm the stomach and dispel cold in traditional Chinese medicine. Ginger is widely used to treat stomach disorders, and it has been reported to exhibit antithrombotic activity via the inhibition of platelet aggregation and thromboxane B2 production in vitro. Cardiovascular disease is associated with the aberrant functioning of the heart and circulatory system; the relatively narrow vessels of the circulation are commonly affected and blocked by atherosclerosis, which may result in angina or heart attack. Numerous drugs and medicines are used to treat myocardial infarction; however, they are often associated with numerous side effects. Therefore, it is important to identify substitutive drugs with no unbearable side effects. In the present study, the relaxant effects of ginger crude extract (GCE) were determined on porcine coronary arteries. The DPPH radical scavenging assay, lucigenin­enhanced chemiluminescence assay and western blot analysis were used to individually detect antioxidant assay of ginger extraction or superoxide anion produced by endothelial cells and molecular signaling. The results indicated that GCE induced relaxation of porcine coronary arteries in an endothelium­dependent manner. GCE increased vasoprotection via the suppression of nitric oxide synthase and cyclooxygenase. In addition, GCE possessed antioxidant ability, as determined using 1,1­diphenyl­2­picrylhydrazyl and lucigenin­enhanced chemiluminescence assays. Taken together, the present study demonstrated that GCE exerts marked vasoprotective effects and free radical­scavenging activities in porcine coronary arteries.

The differential regulation of microRNAs is associated with oral cancer.

Oral squamous cell carcinoma (OSCC), is the most frequently occurring malignant head and neck tumor, generally it exhibits a poor prognosis, and metastasis is the main cause of death in these cancer patients. The discovery of reliable prognostic indicators for tumors progression would greatly improve clinical treatments. MicroRNAs (miRNAs) play a critical role in the degradation of mRNA and the inhibition of protein synthesis. The miRNAs function either as tumor suppressors or as oncogenes in tumorigenesis, and little is known about the clinical significance of miRNA expression profiles in oral cancers. In the present study, we investigated the expression profiles of miR-375, miR-204 and miR-196a in 39 healthy and tumor tissue pairs of oral cancer patients using TaqMan real-time quantitative polymerase chain reaction (qPCR). The predicted target genes for miR-375, miR-204 and miR-196a were confirmed using luciferase reporter-based assays and western blot analyses. In oral cancer tissue, the expression of miR-375 and miR-204 decreased, whereas the expression of miR-196a was significantly elevated. In OSCC, HOXB8 and p27 (CDKN1B) were the direct target genes of miR-196a, whereas HMGA2 was the direct target gene of miR-204. HOXB8 and p27 (CDKN1B) protein expression levels were inhibited by miR-196a, whereas the protein expression level of HMGA2 was inhibited by miR-204. Furthermore, the miR-196a inhibitor blocked cell proliferation. Our results indicate that the combined expression signatures of miR-375, miR-204 and miR-196a are promising biomarkers for the diagnosis, prognosis and treatment of OSCC.

Epigallocatechin gallate sensitizes cisplatin-resistant oral cancer CAR cell apoptosis and autophagy through stimulating AKT/STAT3 pathway and suppressing multidrug resistance 1 signaling.

Epigallocatechin gallate (EGCG) is a green tea polyphenol that presents anticancer activities in multiple cancer cells, but no available report was addressed for the underling molecular mechanism of cytotoxic impacts on drug-resistant oral squamous cell carcinoma cells. In the present study, the inhibitory effects of EGCG were experienced on cisplatin-resistant oral cancer CAR cells. EGCG inhibited cell viability in a time- and concentration-dependent manner by a sulforhodamine B (SRB) assay. EGCG induced CAR cell apoptosis and autophagy by 4',6-diamidino-2-phenylindole (DAPI) dye, acridine orange (AO) staining and green fluorescent protein (GFP)-tagged LC3B assay, respectively. EGCG also significantly enhanced caspase-9 and caspase-3 activities by caspase activity assay. EGCG markedly increased the protein levels of Bax, cleaved caspase-9, cleaved caspase-3, Atg5, Atg7, Atg12, Beclin-1, and LC3B-II, as well as significantly decreased the expression of Bcl-2, phosphorylated AKT (Ser473) and phosphorylation of STAT3 on Tyr705 by western blotting in CAR cells. Importantly, the protein and gene expression of multidrug resistance 1 (MDR1) were dose-dependently inhibited by EGCG. Overall, downregulation of MDR1 levels and alterations of AKT/STAT3 signaling contributed to EGCG-induced apoptosis and autophagy in CAR cells. Based on these results, EGCG has the potential for therapeutic effect on oral cancer and may be useful for long-term oral cancer prevention in the future. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 845-855, 2017.

Antitumor effects of deguelin on H460 human lung cancer cells in vitro and in vivo: Roles of apoptotic cell death and H460 tumor xenografts model.

Deguelin, a naturally occurring rotenoid of the flavonoid family, is known to be an Akt inhibitor, to have chemopreventive activities and anti-tumor effect on several cancers. In this study, investigation to elucidate the effect of deguelin on apoptotic pathways in human lung cancer cells and on the anti-tumor effect in lung cancer xenograft nu/nu mice was performed. In vitro studies, found that deguelin induced cell morphological changes, and decreased the percentage of viability through the induction of apoptosis in H460 lung cancer cells. Deguelin triggered apoptosis in H460 cells was also confirmed by DAPI staining, DNA gel electrophoresis, and Annexin V-FITC staining and these effects are dose-dependent manners. It was also found that deguelin promoted the Ca2+ production and activation of caspase-3 but decreased the level of ΔΨm in H460 cells. Western blots indicated that the protein levels of cytochrome c, AIF, and pro-apoptotic Bax and Bak protein were increased, but the anti-apoptotic Bcl-2 and Bcl-x were decreased that may have led to apoptosis in H460 cells after exposure to deguelin. It was also confirmed by confocal laser microscope examination that deguelin promoted the release of AIF from mitochondria to cytosol. In vivo studies, found that in immunodeficient nu/nu mice bearing H460 tumor xenografts showed that the deguelin significantly suppressed tumor growth. Deguelin might be a potential therapeutic agent for the treatment of lung cancer in the future. This finding might fully support a critical event for deguelin via induction of apoptotic cell death and H460 tumor xenografts model against human lung cancer. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 84-98, 2017.

Gadolinium chloride elicits apoptosis in human osteosarcoma U-2 OS cells through extrinsic signaling, intrinsic pathway and endoplasmic reticulum stress.

Gadolinium (Gd) compounds are important as magnetic resonance imaging (MRI) contrast agents, and are potential anticancer agents. However, no report has shown the effect of gadolinium chloride (GdCl3) on osteosarcoma in vitro. The present study investigated the apoptotic mechanism of GdCl3 on human osteosarcoma U-2 OS cells. Our results indicated that GdCl3 significantly reduced cell viability of U-2 OS cells in a concentration-dependent manner. GdCl3 led to apoptotic cell shrinkage and DNA fragmentation in U-2 OS cells as revealed by morphologic changes and TUNEL staining. Colorimetric assay analyses also showed that activities of caspase-3, caspase-8, caspase-9 and caspase-4 occurred in GdCl3-treated U-2 OS cells. Pretreatment of cells with pan-caspase inhibitor (Z-VAD-FMK) and specific inhibitors of caspase-3/-8/-9 significantly reduced cell death caused by GdCl3. The increase of cytoplasmic Ca2+ level, ROS production and the decrease of mitochondria membrane potential (ΔΨm) were observed by flow cytometric analysis in U-2 OS cells after GdCl3 exposure. Western blot analyses demonstrated that the levels of Fas, FasL, cytochrome c, Apaf-1, GADD153 and GRP78 were upregulated in GdCl3-treated U-2 OS cells. In conclusion, death receptor, mitochondria-dependent and endoplasmic reticulum (ER) stress pathways contribute to GdCl3-induced apoptosis in U-2 OS cells. GdCl3 might have potential to be used in treatment of osteosarcoma patients.

Pharmacological exploitation of the phenothiazine antipsychotics to develop novel antitumor agents-A drug repurposing strategy.

Phenothiazines (PTZs) have been used for the antipsychotic drugs for centuries. However, some of these PTZs have been reported to exhibit antitumor effects by targeting various signaling pathways in vitro and in vivo. Thus, this study was aimed at exploiting trifluoperazine, one of PTZs, to develop potent antitumor agents. This effort culminated in A4 [10-(3-(piperazin-1-yl)propyl)-2-(trifluoromethyl)-10H-phenothiazine] which exhibited multi-fold higher apoptosis-inducing activity than the parent compound in oral cancer cells. Compared to trifluoperazine, A4 demonstrated similar regulation on the phosphorylation or expression of multiple molecular targets including Akt, p38, and ERK. In addition, A4 induced autophagy, as evidenced by increased expression of the autophagy biomarkers LC3B-II and Atg5, and autophagosomes formation. The antitumor activity of A4 also related to production of reactive oxygen species and adenosine monophosphate-activated protein kinase. Importantly, the antitumor utility of A4 was extended in vivo as it, administrated at 10 and 20 mg/kg intraperitoneally, suppressed the growth of Ca922 xenograft tumors. In conclusion, the ability of A4 to target diverse aspects of cancer cell growth suggests its value in oral cancer therapy.

Inhibitory effects of tetrandrine on epidermal growth factor-induced invasion and migration in HT29 human colorectal adenocarcinoma cells.

Tetrandrine has been shown to reduce cancer cell proliferation and to inhibit metastatic effects in multiple cancer models in vitro and in vivo. However, the effects of tetrandrine on the underlying mechanism of HT29 human colorectal adenocarcinoma cell metastasis remain to be fully elucidated. The aim of the present study was focused on tetrandrine­treated HT29 cells following epidermal growth factor (EGF) treatment, and Transwell, gelatin zymography, gene expression and immunoblotting assays were performed to investigate metastatic effects in vitro. Tetrandrine was observed to dose­dependently inhibit EGF­induced HT29 cell invasion and migration, however, no effect on cell viability occurred following exposure to tetradrine between 0.5 and 2 µM. Tetrandrine treatment inhibited the enzymatic activity of matrix metalloprotease (MMP)­2 and MMP­9 in a concentration­dependent manner. The present study also found a reduction in the mRNA expression levels of MMP­2 and MMP­9 in the tetrandrine­treated HT29 cells. Tetrandrine also suppressed the phosphorylation of EGF receptor (EGFR) and its downstream pathway, including phosphoinositide­dependent kinase 1, phosphatidylinositol 3­kinase and phosphorylated AKT, suppressing the gene expression of MMP­2 and MMP­9. Furthermore, tetrandrine triggered mitogen­activated protein kinase signaling through the suppressing the activation of phosphorylated extracellular signal­regulated protein kinase. These data suggested that targeting EGFR signaling and its downstream molecules contributed to the inhibition of EGF­induced HT29 cell metastasis caused by tetrandrine, eventually leading to a reduction in the mRNA and gelatinase activities of MMP-2 and MMP-9, respectively.