Polyphyllin G induces apoptosis and autophagy cell death in human oral cancer cells

Exploiting new strategies in combating head and neck carcinoma: A comprehensive review on phytochemical approaches passing through PI3K/Akt/mTOR signaling pathway

Recently, malignant neoplasms have growingly caused human morbidity and mortality. Head and neck cancer (HNC) constitutes a substantial group of malignancies occurring in various anatomical regions of the head and neck, including lips, mouth, throat, larynx, nose, sinuses, oropharynx, hypopharynx, nasopharynx, and salivary glands. The present study addresses the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway as a possible therapeutic target in cancer therapy. Finding new multitargeting agents capable of modulating PI3K/Akt/mTOR and cross-linked mediators could be viewed as an effective strategy in combating HNC. Recent studies have introduced phytochemicals as multitargeting agents and rich sources for finding and developing new therapeutic agents. Phytochemicals have exhibited immense anticancer effects, including targeting different stages of HNC through the modulation of several signaling pathways. Moreover, phenolic/polyphenolic compounds, alkaloids, terpenes/terpenoids, and other secondary metabolites have demonstrated promising anticancer activities because of their diverse pharmacological and biological properties like antiproliferative, antineoplastic, antioxidant, and anti-inflammatory activities. The current review is mainly focused on new therapeutic strategies for HNC passing through the PI3K/Akt/mTOR pathway as new strategies in combating HNC.

The mechanism of polyphyllin in the treatment of gastric cancer was verified based on network pharmacology and experimental validation

Background

Polyphyllin is a class of saponins extracted from Paris polyphylla rhizomes and has been used in clinical application in China for more than 2000 years. However, the mechanism for treating gastric cancer (GC) is still unclear. This study was designed to predict the targets and mechanisms of total Polyphyllin from Paris polyphylla rhizomes for the treatment of GC.

Method

Firstly, PubChem and Swiss Target Prediction databases were utilized to collect the 12 ingredients of total Polyphyllin from Paris polyphylla rhizomes and their targets. GC-related genes were obtained from the GEO database. Then the intersecting targets to all these molecules that identified using Venny. Secondly, the intersecting targets were imported into STRING platform for protein-protein interaction (PPI) network. Moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted in DAVID website. In addition, the GEPIA was applied to perform the expression levels, transcript levels, staging, and overall survival of hub genes. In addition, we used AutoDock Vina to evaluate binding affinity of molecular docking between key ingredients and anti-GC targets. In vitro cell experiments, we detected the cell viability of gastric cancer cells at 24, 36, and 48 h using CCK-8 assay. The G0/G1 of cell cycle and apoptosis were detected by flow cytometry. Finally, quantitative real time polymerase chain reaction (qRT-PCR) was used to detect the level of hub genes, and Western blot was used to detect the changes of PI3K/Akt signal pathway.

Results

Firstly, we identified 12 ingredients and 286 targets of total Polyphyllin. A total of 2653 GC-related differentially expressed genes (DEGs) were collected, including 1366 up-regulated genes and 1287 down-regulated genes. Moreover, 45 targets were obtained after intersection. Secondly, results of the GO enrichment suggested that these genes were closely related to cell proliferation, migration and aging. KEGG analysis suggested that Polyphyllin in GC therapy were mostly regulated by multiple pathways, including the pathways in cancer, calcium signaling pathway, Rap1 signaling pathway, phospholipase D signaling pathway, etc. In addition, GEPIA results exhibited that PDGFRB, KIT, FGF1, GLI1, F2R, and HIF1A were associated with GC progression, stage, and survival. Besides, the molecular docking results further confirmed that the binding energy of Polyphyllin Ⅲ with HIF1A was minimal. In vitro cell experiments, Polyphyllin Ⅲ inhibited the cell viability of gastric cancer cells, blocked the cell cycle G0/G1 phase, and induced cell apoptosis. In addition, Polyphyllin Ⅲ down-regulated the mRNA levels of PDGFRB, KIT, FGF1, GLI1, F2R, and HIF1A, and regulated the PI3K/Akt signal pathway.

Conclusions

The results revealed that total Polyphyllin treated GC through multiple targets, multiple channels, and multiple pathways. In addition, Polyphyllin Ⅲ played an anti-gastric cancer role by inhibiting the proliferation of gastric cancer.

Steroid and triterpenoid saponins from the rhizomes of Paris polyphylla var. stenophylla

Five new saponins, including three steroid saponins, paristenoids A-C (1-3), and two triterpenoid saponins, paristenoids D-E (4-5), along with four known ones (6-9) were isolated from the rhizomes of Paris polyphylla var. stenophylla. The structures of the isolated compounds were identified mainly by detailed spectroscopic analysis, including extensive 1D and 2D NMR, MS, as well as chemical methods. Compound 3 is a new cyclocholestanol-type steroidal saponin with a rare 6/6/6/5/5 fused-rings cholestanol skeleton, and this skeleton has been first found from the genus Paris. The cytotoxicities of the isolated compounds against three human three glioma cell lines (U87MG, U251MG and SHG44) were evaluated, and compound 7 displayed certain inhibitory effect with IC50 values of 15.22 ± 1.73, 18.87 ± 1.81 and 17.64 ± 1.69 μmol·L-1, respectively.

Paris saponins Ⅶ inhibits glycolysis of ovarian cancer via the RORC/ACK1 signaling pathway

Rhizoma Paridis is a traditional Chinese medicine commonly used for treatment of malignant tumors. Paris saponins Ⅶ (PSⅦ) is one of the components of Rhizoma Paridis, but the role of PSⅦ in glucose metabolism in ovarian cancer remains elucidated. A series of experiments in the current study demonstrated that PSⅦ inhibites glycolysis and promotes cell apoptosis in ovarian cancer cells. Expression levels of glycolysis-related proteins and apoptosis-related proteins were significantly altered by upon treatment with PSⅦ, as determined from western blot analyses. Mechanistically, PSⅦ exerted its anti-tumor effects by targeting the RORC/ACK1 signaling pathway. These findings indicate that PSⅦ inhibits glycolysis-induced cell proliferation and apoptosis through the RORC/ACK1 pathway, supporting its potential development as a candidate chemotherapeutic agent for ovarian cancer.

Polyphyllin VII protects from breast cancer-induced osteolysis by suppressing osteoclastogenesis via c-Fos/NFATc1 signaling

Bone is a preferred metastatic site of advanced breast cancer and the 5-year overall survival rate of breast cancer patients with bone metastasis is only 22.8%. Targeted inhibition of osteoclasts can treat skeletal-related events (SREs) in breast cancer patients. Polyphyllin VII (PP7), a pennogenyl saponin isolated from traditional Chinese herb Paris polyphylla, exhibits strong anti-inflammatory and anti-cancer activities. In this study, we evaluated the effect of PP7 on metastatic breast cancer-induced bone destruction in vivo and the underlying mechanisms. We found that intraperitoneal injection of 1 mg/kg PP7 significantly ameliorated the breast cancer MDA-MB-231 cell-induced osteolysis in mice. Mechanistically, PP7 (0.125-0.5 μM) inhibited the conditioned medium of MDA-MB-231 cells (MDA-MB-231 CM)-induced osteoclast formation in bone marrow-derived macrophages (BMMs). Furthermore, PP7 markedly reduced MDA-MB-231 CM-induced osteoclastic bone resorption and F-actin rings formation in vitro. During MDA-MB-231 CM-induced osteoclastogenesis, the activation of c-Fos and NFATc1 signaling was significantly downregulated by PP7, and finally osteoclast-related genes such as Oscar, Atp6v0d2, Mmp9 and β3 integrin were decreased. In addition, the formation of osteoblast was promoted by PP7 treatment. Our current findings revealed PP7 as a potential safe agent for preventing and treating bone destruction in breast cancer patients with bone metastases.

Paris polyphylla Sm. Induces Reactive Oxygen Species and Caspase 3-Mediated Apoptosis in Colorectal Cancer Cells In Vitro and Potentiates the Therapeutic Significance of Fluorouracil and Cisplatin

Paris polyphylla Sm. (Melanthiaceae) is an essential, vulnerable herb with a wide range of traditional applications ranging from fever to cancer in various communities. The use of P. polyphylla in India is limited to traditional healers. Here, we demonstrated that P. polyphylla extract (PPE) has good phenol, flavonoid, saponin, and steroidal saponin content and anti-oxidant activity with IC₅₀ 35.12 ± 6.1 μg/mL in DPPH and 19.69 ± 6.7 μg/mL in ABTS. Furthermore, PPE induces cytotoxicity in HCT-116 with IC₅₀ 8.72 ± 0.71 μg/mL without significant cytotoxicity inthe normal human colon epithelial cell line, CCD 841 CoN. PPE inhibits the metastatic property and induces apoptosis in HCT-116, as measured by Annexin V/PI, by increasing the production of reactive oxygen species (ROS) and caspase 3 activation. PPE acts synergistically with 5FU and cisplatin in HCT-116 and potentiates their therapeutic significance. Steroidal saponins with anticancer activities were detected in PPE by HR-LCMS. The present study demonstrated that PPE induces apoptosis by increasing ROS and activating caspase 3, which was attributed to steroidal saponins. PPE can be used as a potential natural remedy for colon cancer.

A simple and sensitive LC-MS/MS method for the determination of polyphyllin VII in rat plasma and its application to pharmacokinetic study

Polyphyllin VII is an isoprene saponin extracted from Rhizoma paridis, and it can effectively suppress tumor initiation, growth, and metastasis. In this study, we aim to develop and validate an LC-MS/MS method for the quantification of polyphyllin VII in rat plasma using digoxin as the internal standard (IS). The plasma samples were precipitated with methanol, and the samples were separated on an ACQUITY BEH C₁₈ column (2.1 × 50 mm, 1.7 μm). The mobile phase consisted of 0.1% formic acid solution and acetonitrile. The detection was performed in the multiple reactions monitoring mode, with the precursor-to-product transitions of m/z 1075.4 > 883.3 for polyphyllin VII and m/z 779.4 > 649.6 for the IS. The method showed excellent linearity over the concentration range of 0.5-1000 ng/ml, with a correlation coefficient of 0.9996 (r = 0.9996). The lower limit of quantification was 0.5 ng/ml. The inter- and intra-day accuracy (relative error) ranged from -4.8 to 5.9%, and precision (relative standard deviation) was < 9.0%. The assay showed high extraction recovery, ranging from 90.6 to 95.6%. Polyphyllin VII was demonstrated to be stable under the storage conditions. The validated LC-MS/MS method was successfully applied to the pharmacokinetic study of polyphyllin VII in rats after oral, intraperitoneal, and intravenous administrations. The pharmacokinetic results indicated that polyphyllin VII showed low oral (5.86%) bioavailability and moderate (38.81%) intraperitoneal bioavailability.

Separation and Purification of Two Saponins from Paris polyphylla var. yunnanensis by a Macroporous Resin

An effective method for separating and purifying critical saponins (polyphyllin II and polyphyllin VII) from a Paris polyphylla var. yunnanensis extract was developed in this study which was environmentally friendly and economical. Static adsorption kinetics, thermodynamics, and the dynamic adsorption-desorption of macroporous resins were investigated, and then the conditions of purification and separation were optimized by fitting with an adsorption thermodynamics equation and a kinetic equation. Effective NKA-9 resin from seven macroporous resins was screened out to separate and purify the two saponins. The static adsorption and dynamic adsorption were chemical and physical adsorption dual-processes on the NKA-9 resin. Under the optimum parameters, the contents of polyphyllin II and polyphyllin VII in the product were 17.3-fold and 28.6-fold those in plant extracts, respectively. The total yields of the two saponins were 93.16%. This research thus provides a theoretical foundation for the large-scale industrial production of the natural drugs polyphyllin II and polyphyllin VII.

MAPK Signaling Pathway in Oral Squamous Cell Carcinoma: Biological Function and Targeted Therapy

Oral squamous cell carcinoma accounts for 95% of human head and neck squamous cell carcinoma cases. It is highly malignant and aggressive, with a poor prognosis and a 5-year survival rate of <50%. In recent years, basic and clinical studies have been performed on the role of the mitogen-activated protein kinase (MAPK) signaling pathway in oral cancer. The MAPK signaling pathway is activated in over 50% of human oral cancer cases. Herein, we review research progress on the MAPK signaling pathway and its potential therapeutic mechanisms and discuss its molecular targeting to explore its potential as a therapeutic strategy for oral squamous cell carcinoma.

Stellettin B-Induced Oral Cancer Cell Death via Endoplasmic Reticulum Stress-Mitochondrial Apoptotic and Autophagic Signaling Pathway

Oral squamous cell carcinoma (OSCC) affects tens of thousands of people worldwide. Despite advances in cancer treatment, the 5-year survival rate of patients with late-stage OSCC is low at 50–60%. Therefore, the development of anti-OSCC therapy is necessary. We evaluated the effects of marine-derived triterpene stellettin B in human OC2 and SCC4 cells. Stellettin B dose-dependently decreased the viability of both cell lines, with a significant reduction in OC2 cells at ≥0.1 µM at 24 and 48 h, and in SCC4 cells at ≥1 µM at 24 and 48 h. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive cells were significantly observed at 20 µM of stellettin B at 48 h, with the overexpression of cleaved caspase3 and cleaved poly(ADP-ribose) polymerase (PARP). Moreover, mitochondrial respiratory functions were ablated by stellettin B. Autophagy-related LC3-II/LC3-I ratio and Beclin-1 proteins were increased, whereas p62 was decreased. At 20 µM at 48 h, the expression levels of the endoplasmic reticulum (ER) stress biomarkers calnexin and BiP/GRP78 were significantly increased and mitogen-activated protein kinase (MAPK) signaling pathways were activated. Further investigation using the autophagy inhibitor 3-methyladenine (3-MA) demonstrated that it alleviated stellettin B-induced cell death and autophagy. Overall, our findings show that stellettin B induces the ER stress, mitochondrial stress, apoptosis, and autophagy, causing cell death of OSCC cells.

Qizhen capsule inhibits colorectal cancer by inducing NAG-1/GDF15 expression that mediated via MAPK/ERK activation

ETHNOPHARMACOLOGICAL RELEVANCE

Qizhen capsule (QZC) is a traditional Chinese medicine (TCM) preparation that has been widely used in clinical practice and exerts promising therapeutic effects against breast, lung, and gastric cancers. However, studies have not reported whether QZC inhibits colorectal cancer (CRC) development and progression. Meanwhile, the underlying molecular mechanisms of its anticancer activity have not been studied.

AIM OF THE STUDY

To investigate the anticancer effects of QZC on CRC and the possible underlying molecular mechanisms of QZC in vitro and in vivo.

MATERIALS AND METHODS

The MTT assay and flow cytometry were used to determine the viability and apoptosis of HCT116 and HT-29 cancer cells. A xenograft nude mouse model was used to study the antitumor effects of QZC in vivo. Western blotting was performed to determine the expression of key proteins responsible for the molecular mechanisms elicited by QZC. Immunofluorescence staining was performed to detect the expression of nonsteroidal anti-inflammatory drug (NSAID)-activated gene-1 or growth differentiation factor-15 (NAG-1/GDF15). Small interfering RNAs (siRNAs) were used to silence NAG-1/GDF15 in cells.

RESULTS

In this study, QZC significantly reduced the viability of HCT116 and HT-29 cells and induced apoptosis in dose- and time-dependent manners, but displayed much less toxicity toward normal cells. QZC-induced apoptosis in HCT116 cells was accompanied by the deregulation of the expression of the Bcl-2, Bax, PARP, caspase-3, and caspase-9 proteins. Furthermore, QZC induced NAG-1/GDF15 expression in HCT116 cells, while silencing of NAG-1/GDF15 attenuated QZC-induced apoptosis and cell death. Next, QZC increased the phosphorylation of mTOR, AMPK, p38, and MAPK/ERK in HCT116 cells. We then demonstrated that QZC-induced apoptosis and NAG-1/GDF15 upregulation were mediated by MAPK/ERK activation. Moreover, QZC significantly inhibited HCT116 xenograft tumor growth in nude mice, which was accompanied by NAG/GDF15 upregulation and MAPK/ERK activation. QZC also prevented 5-FU-induced weight loss or cachexia in tumor-bearing mice. The expression of Ki67 and PCNA was suppressed, while cleaved caspase-3 level and TUNEL staining were increased in the tumor sections from QZC-treated mice compared to the control.

CONCLUSION

QZC is a novel anticancer agent for CRC that targets NAG-1/GDF15 via the MAPK/ERK signaling pathway.

Platyphyllenone Induces Autophagy and Apoptosis by Modulating the AKT and JNK Mitogen-Activated Protein Kinase Pathways in Oral Cancer Cells

Platyphyllenone is a type of diarylheptanoid that exhibits anti-inflammatory and chemoprotective effects. However, its effect on oral cancer remains unclear. In this study, we investigated whether platyphyllenone can promote apoptosis and autophagy in SCC-9 and SCC-47 cells. We found that it dose-dependently promoted the cleavage of PARP; caspase-3, -8, and -9 protein expression; and also led to cell cycle arrest at the G2/M phase. Platyphyllenone up-regulated LC3-II and p62 protein expression in both SCC-9 and SCC-47 cell lines, implying that it can induce autophagy. Furthermore, the results demonstrated that platyphyllenone significantly decreased p-AKT and increased p-JNK1/2 mitogen-activated protein kinase (MAPK) signaling pathway in a dose-dependent manner. The specific inhibitors of p-JNK1/2 also reduced platyphyllenone-induced cleavage of PARP, caspase-3, and caspase -8, LC3-II and p62 protein expression. These findings are the first to demonstrate that platyphyllenone can induce both autophagy and apoptosis in oral cancers, and it is expected to provide a therapeutic option as a chemopreventive agent against oral cancer proliferation.

Natural Polyphyllins (I, II, D, VI, VII) Reverses Cancer Through Apoptosis, Autophagy, Mitophagy, Inflammation, and Necroptosis

Cancer is the second leading cause of mortality worldwide. Conventional therapies, including surgery, radiation, and chemotherapy, have limited success because of secondary resistance. Therefore, safe, non-resistant, less toxic, and convenient drugs are urgently required. Natural products (NPs), primarily sourced from medicinal plants, are ideal for cancer treatment because of their low toxicity and high success. NPs cure cancer by regulating different pathways, such as PI3K/AKT/mTOR, ER stress, JNK, Wnt, STAT3, MAPKs, NF-kB, MEK-ERK, inflammation, oxidative stress, apoptosis, autophagy, mitophagy, and necroptosis. Among the NPs, steroid saponins, including polyphyllins (I, II, D, VI, and VII), have potent pharmacological, analgesic, and anticancer activities for the induction of cytotoxicity. Recent research has demonstrated that polyphyllins (PPs) possess potent effects against different cancers through apoptosis, autophagy, inflammation, and necroptosis. This review summarizes the available studies on PPs against cancer to provide a basis for future research.

Targeting autophagy using saponins as a therapeutic and preventive strategy against human diseases

Autophagy is a ubiquitous mechanism for maintaining cellular homeostasis through the degradation of long-lived proteins, insoluble protein aggregates, and superfluous or damaged organelles. Dysfunctional autophagy is observed in a variety of human diseases. With advanced research into the role that autophagy plays in physiological and pathological conditions, targeting autophagy is becoming a novel tactic for disease management. Saponins are naturally occurring glycosides containing triterpenoids or steroidal sapogenins as aglycones, and some saponins are reported to modulate autophagy. Research suggests that saponins may have therapeutic and preventive efficacy against many autophagy-related diseases. Therefore, this review comprehensively summarizes and discusses the reported saponins that exhibit autophagy regulating activities. In addition, the relevant signaling pathways that the mechanisms involved in regulating autophagy and the targeted diseases were also discussed. By regulating autophagy and related pathways, saponins exhibit bioactivities against cancer, neurodegenerative diseases, atherosclerosis and other cardiac diseases, kidney diseases, liver diseases, acute pancreatitis, and osteoporosis. This review provides an overview of the autophagy-regulating activity of saponins, the underlying mechanisms and potential applications for managing various diseases.

Molecular mechanisms of anticancer activities of polyphyllin VII

Cancer is the leading cause of mortality in the world. The major therapies for cancer treatment are chemotherapy, surgery, and radiation therapy. All these therapies expensive, toxic and show resistance. The plant-derived compounds are considered safe, cost-effective and target cancer through different pathways. In these pathways include oxidative stress, mitochondrial dependent and independent, STAT3, NF-kB, MAPKs, cell cycle, and autophagy pathways. One of the new plants derived compounds is Polyphyllin VII (PPVII), which target cancer through different molecular mechanisms. In literature, there is a review gap of studies on PPVII; therefore in the current review, we summarized the available studies on PPVII to provide a base for future research.

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field.

Polyphyllin VII suppresses cell proliferation, the cell cycle and cell migration in colorectal cancer

Colorectal cancer (CRC) is one of the most common types of human cancer. However, there is still an urgent need to identify novel treatment strategies for CRC. The present study aimed to validate the potential antitumor effects of polyphyllin VII in CRC. The present study revealed that polyphyllin VII could significantly inhibit CRC proliferation and induce cell cycle arrest and apoptosis. Moreover, the anti-metastatic effect of polyphyllin VII in CRC cells was implicated. Microarray analysis identified that polyphyllin VII could affect multiple protein coding genes and non-coding RNAs. Bioinformatics analysis revealed that polyphyllin VII regulated multiple pathways in CRC, including ‘ER to Golgi vesicle-mediated transport’, ‘response to cAMP’, ‘Ras protein signal transduction’, ‘metabolic pathways’, ‘MAPK signaling pathway’ and ‘cell cycle’. Protein-Protein Interaction network analysis identified a series of key polyphyllin VII-regulating genes in CRC, including ribonucleoside-diphosphate reductase subunit M2, structural maintenance of chromosomes protein 4 and DNA replication licensing factor MCM4. Finally, the present results demonstrated that these key polyphyllin VII-regulating genes were dysregulated in CRC. Taken together, these results indicated that polyphyllin VII could be a novel antitumor drug for the treatment of CRC.

Cinnamaldehyde Treatment of Prostate Cancer-Associated Fibroblasts Prevents Their Inhibitory Effect on T Cells Through Toll-Like Receptor 4

Introduction

Cancer-associated fibroblasts (CAFs) promote tumor progression; thus, drugs that can modify CAFs need to be identified.

Methods

To test the effect of cinnamaldehyde on prostate CAFs, the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-2H-tetrazolium bromide assay was used to determine their survival. When spleen cells were treated with CAF supernatant, the proliferation of T cells was inhibited as determined by flow cytometry. After cinnamaldehyde treatment, this immunosuppressive function of CAFs was partially reversed. To explore the molecular mechanism, Western blotting and the quantitative real-time polymerase chain reaction were applied, and TLR4-dependent signaling pathway-related protein and mRNA levels were quantified.

Results

Cinnamaldehyde acted on the TLR4-dependent signaling pathway, altering the function of CAFs such that its supernatant no longer inhibited the proliferation of T cells.

Conclusion

These data indicate that cinnamaldehyde can modify the functions of CAFs, which may be helpful for treating tumors. Cinnamaldehyde can suppress CAF T-cell inhibition.

Anticancer effects of a traditional Thai herbal recipe Benja Amarit extracts against human hepatocellular carcinoma and colon cancer cell by targeting apoptosis pathways

ETHNOPHARMACOLOGICAL RELEVANCE

A preparation of Benja Amarit (BJA) has been effectively used in folk medicine to treat diseases related to the liver and colon and forms of cancer for hundreds of years in Thailand. However, there has not been any research on BJA with regard to its anticancer activity against human hepatocellular carcinoma and colon cancer cells.

AIM OF THE STUDY

This study was to obtain the scientific supports for the traditional usage in anticancer potential of BJA extracts on hepatocellular carcinoma and colon cancer.

MATERIALS AND METHODS

The cytotoxic effects were determined using MTT assay. Apoptosis was quantitated by annexin V-FITC/PI staining. Caspases activities were measured by using specific substrates and colorimetric analysis. The protein expressions were determined by Western blot analysis. Reactive oxygen species (ROS) generation, mitochondrial transmembrane potential, and calcium ion levels were measured by specific fluorescence probes and flow cytometry. The chick embryo chorioallantoic membrane model has been used to study the in vivo anticancer activity. The phytochemical identification was performed by GC-MS and LC-MS.

RESULTS

Notably, 95% (BJA-95) and 50% (BJA-50) ethanolic extract of BJA inhibited hepatocellular carcinoma and colon cancer cell viability in a dose-dependent manner. While, the water extract of BJA (BJA-W) was not found to be toxic to both kinds of cancer cell lines. BJA extract induced both the extrinsic and intrinsic or mitochondria-mediated apoptosis pathways. Moreover, BJA-95 caused ROS generation and endoplasmic reticulum stress-mediated apoptosis. The extract exhibited the growth inhibitory effects on cancer cells in vivo. Phytochemical analysis revealed that the major active compounds were piperine, xanthotoxol and dihydrogambogic acid.

CONCLUSION

This study is the first to demonstrate anticancer efficiency of BJA extracts on human cancer cells. We consider BJA extract to be a potentially alternative cancer treatment and to be a promising candidate in the future development of antitumor agents.

Targeting AKT/mTOR in Oral Cancer: Mechanisms and Advances in Clinical Trials

Oral cancer (OC) is a devastating disease that takes the lives of lots of people globally every year. The current spectrum of treatment modalities does not meet the needs of the patients. The disease heterogeneity demands personalized medicine or targeted therapies. Therefore, there is an urgent need to identify potential targets for the treatment of OC. Abundant evidence has suggested that the components of the protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) pathway are intrinsic factors for carcinogenesis. The AKT protein is central to the proliferation and survival of normal and cancer cells, and its downstream protein, mTOR, also plays an indispensable role in the cellular processes. The wide involvement of the AKT/mTOR pathway has been noted in oral squamous cell carcinoma (OSCC). This axis significantly regulates the various hallmarks of cancer, like proliferation, survival, angiogenesis, invasion, metastasis, autophagy, and epithelial-to-mesenchymal transition (EMT). Activated AKT/mTOR signaling is also associated with circadian signaling, chemoresistance and radio-resistance in OC cells. Several miRNAs, circRNAs and lncRNAs also modulate this pathway. The association of this axis with the process of tumorigenesis has culminated in the identification of its specific inhibitors for the prevention and treatment of OC. In this review, we discussed the significance of AKT/mTOR signaling in OC and its potential as a therapeutic target for the management of OC. This article also provided an update on several AKT/mTOR inhibitors that emerged as promising candidates for therapeutic interventions against OC/head and neck cancer (HNC) in clinical studies.

Polyphyllin VII induces fibroblasts apoptosis via the ERK/JNK pathway

Hypertrophic scar (HS) is a pathological scar that often occurs in burn patients. Its histology is characterized by the excessive proliferation of fibroblasts (FB) and excessive accumulation of extracellular matrix (ECM). Inhibition of proliferation and activation of FB is essential for the treatment of HS. The crude extracts of traditional Chinese medicines have beneficial therapeutic effects on HS besides possessing fewer side effects and being easily available. Polyphyllin VII (PP7) is an isoprene saponin isolated from Rhizoma paridis. It has a pro-apoptotic effect on cancer cells. In the present study, we demonstrate that PP7 exerts a significant inhibitory effect on hypertrophic scar fibroblasts (HSFs) in vitro. We also demonstrate that PP7 considerably induces the apoptosis of HSFs and inhibits their activity. Our data show that the PP7-induced HSFs cell apoptosis was mainly due to the enhanced expression of apoptotic genes (Bax, Caspase-3, Caspase-9) and decreased expression of Bcl-2. Moreover, PP7 treatment also enhances the expression of JNK, but that of extracellular protein kinases (ERK) was reduced, and induces apoptosis through ERK/JNK pathways. Thus, PP7 can be used as a drug to prevent the formation of HS.

How autophagy can restore proteostasis defects in multiple diseases?

Cellular evolution develops several conserved mechanisms by which cells can tolerate various difficult conditions and overall maintain homeostasis. Autophagy is a well-developed and evolutionarily conserved mechanism of catabolism, which endorses the degradation of foreign and endogenous materials via autolysosome. To decrease the burden of the ubiquitin-proteasome system (UPS), autophagy also promotes the selective degradation of proteins in a tightly regulated way to improve the physiological balance of cellular proteostasis that may get perturbed due to the accumulation of misfolded proteins. However, the diverse as well as selective clearance of unwanted materials and regulations of several cellular mechanisms via autophagy is still a critical mystery. Also, the failure of autophagy causes an increase in the accumulation of harmful protein aggregates that may lead to neurodegeneration. Therefore, it is necessary to address this multifactorial threat for in-depth research and develop more effective therapeutic strategies against lethal autophagy alterations. In this paper, we discuss the most relevant and recent reports on autophagy modulations and their impact on neurodegeneration and other complex disorders. We have summarized various pharmacological findings linked with the induction and suppression of autophagy mechanism and their promising preclinical and clinical applications to provide therapeutic solutions against neurodegeneration. The conclusion, key questions, and future prospectives sections summarize fundamental challenges and their possible feasible solutions linked with autophagy mechanism to potentially design an impactful therapeutic niche to treat neurodegenerative diseases and imperfect aging.

Polyphyllin VII induces apoptotic cell death via inhibition of the PI3K/Akt and NF‑κB pathways in A549 human lung cancer cells

Polyphyllin VII is an active compound isolated from Paris polyphylla, which is termed Chonglou in China. The present study was designed to investigate the underlying mechanisms of the antitumor effect of Polyphyllin VII in lung cancer cells. The cytotoxic effect of Polyphyllin VII in human lung cancer A549 cells was analyzed; the results revealed an IC₅₀ value of 0.41±0.10 µM at 24 h. The associated mechanisms were investigated by phase-contrast microscopy, fluorescence microscopy, flow cytometry and western blot analysis. Exposure of A549 cells to Polyphyllin VII resulted in apoptosis. Pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, and wortmannin, an inhibitor of PI3K, both decreased the proportion of viable A549 cells in the presence of Polyphyllin VII. The ratio of apoptotic cells increased in the presence of wortmannin and PDTC. Western blot analysis revealed that PI3K, phosphorylated (p)-PI3K, Akt, p-Akt, NF-κB and p-NF-κB were downregulated following treatment with Polyphyllin VII. Increased caspase-3 activity, increased poly-(ADP-ribose) polymerase cleavage and a downregulation of inhibitor of caspase-activated DNase were observed following treatment with Polyphyllin VII, and these effects were enhanced by either wortmannin or PDTC. The present results revealed that Polyphyllin VII was able to induce apoptotic cell death in A549 human lung cancer cells via inhibition of the PI3K/Akt and NF-κB pathways.

Autophagy modulators for the treatment of oral and esophageal squamous cell carcinomas

Oral squamous cell carcinomas (OSCC) and esophageal squamous cell carcinomas (ESCC) exhibit a survival rate of less than 60% and 40%, respectively. Late-stage diagnosis and lack of effective treatment strategies make both OSCC and ESCC a significant health burden. Autophagy, a lysosome-dependent catabolic process, involves the degradation of intracellular components to maintain cell homeostasis. Targeting autophagy has been highlighted as a feasible therapeutic strategy with clinical utility in cancer treatment, although its associated regulatory mechanisms remain elusive. The detection of relevant biomarkers in biological fluids has been anticipated to facilitate early diagnosis and/or prognosis for these tumors. In this context, recent studies have indicated the presence of specific proteins and small RNAs, detectable in circulating plasma and serum, as biomarkers. Interestingly, the interplay between biomarkers (eg, exosomal microRNAs) and autophagic processes could be exploited in the quest for targeted and more effective therapies for OSCC and ESCC. In this review, we give an overview of the available biomarkers and innovative targeted therapeutic strategies, including the application of autophagy modulators in OSCC and ESCC. Additionally, we provide a viewpoint on the state of the art and on future therapeutic perspectives combining the early detection of relevant biomarkers with drug discovery for the treatment of OSCC and ESCC.

Polyphyllin I and VII potentiate the chemosensitivity of A549/DDP cells to cisplatin by enhancing apoptosis, reversing EMT and suppressing the CIP2A/AKT/mTOR signaling axis

Poor response and resistance to cisplatin (DDP)-based chemotherapy frequently leads to treatment failure in advanced non-small cell lung cancer (NSCLC). The underlying molecular mechanism is extremely complex and currently remains unclear. The overexpression of cancerous inhibitor of protein phosphatase 2A (CIP2A) indicates poor prognosis and promotes the epithelial-to-mesenchymal transition (EMT) and metastasis. The EMT has been reported to promote drug resistance in numerous previous studies. CIP2A and its downstream protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway also plays a role in mediating DDP resistance. Polyphyllin I (PPI) and polyphyllin VII (PPVII) are natural components extracted from Paris polyphylla that display anti-cancer properties. In the present study, the chemosensitizing effects of PPI and PPVII were investigated in the DDP-resistant NSCLC cell line A549/DDP, as well as the underlying molecular mechanisms. The results demonstrated that PPI and PPVII could significantly inhibit cell proliferation and enhance the sensitivities of A549/DDP cells to DDP. When assessing the underlying molecular mechanism, it was revealed that PPI and PPVII enhanced DDP-induced apoptosis in A549/DDP cells via p53 upregulation and the caspase-dependent pathway. Furthermore, PPI and PPVII reversed the EMT and suppressed CIP2A and its downstream AKT/mTOR signaling cascade in A549/DDP cells. Overall, the results from the present study demonstrated that PPI and PPVII may function as chemosensitizers by enhancing apoptosis via the p53 pathway, reversing EMT and suppressing the CIP2A/AKT/mTOR signaling axis, and the combination with DDP may be a promising strategy for the development of new therapeutic agents.

Polyphyllin I induces autophagy and cell cycle arrest via inhibiting PDK1/Akt/mTOR signal and downregulating cyclin B1 in human gastric carcinoma HGC-27 cells

Paris polyphylla. is a traditional medicinal herb that has long been used to prevent cancer in many Asian countries. Polyphyllin I (PPI), an important bioactive constituent of Paris polyphylla, has been found to exhibit a wide variety of anticancer activities in many types of cancer cells. However, the effects of PPI on human gastric carcinoma cells and its mechanism of action remain unclear. In this study, we examined the effective anti-gastric carcinoma activity of PPI and its underlying mechanism of action in HGC-27 cells. In vitro, sub-micromolar concentrations of PPI inhibited HGC-27 cell proliferation with an IC₅₀ of 0.34 ± 0.06 μM after a 72-h treatment. In vivo, 3 mg/kg PPI significantly inhibited proliferation of HGC-27 tumor cells, with a 78.8% inhibition rate compared to paclitaxel, and demonstrated higher safety. Analysis of MDC and mGFP-LC3 fluorescence, Western blotting and flow cytometry indicated that PPI induced cell cycle arrest in HGC-27 cells by promoting the conversion of LC3-I to LC3-II and by downregulating cyclin B1. Furthermore, Western blotting showed that PPI inhibited the autophagy-regulating PDK1/Akt/mTOR signaling pathway in vitro and in vivo. In addition, immunohistochemistry and TUNEL staining revealed that PPI decreased Ki67 expression and increased the percentage of apoptotic cells in HGC-27 xenograft tumors. These data indicate that PPI is an PDK1/Akt/mTOR signaling inhibitor and of therapeutic relevance for gastric cancer treatment and that the rhizome of Paris polyphylla deserves further clinical investigation as an alternative therapy for gastric cancer.

Celastrol, a plant-derived triterpene, induces cisplatin-resistance nasopharyngeal carcinoma cancer cell apoptosis though ERK1/2 and p38 MAPK signaling pathway

BACKGROUND

Developing resistance to chemotherapeutic drugs has become a major problem in the management of nasopharyngeal carcinoma (NPC). To overcome this issue, use of natural plant products as chemosensitizers is gaining importance at a fast pace.

HYPOTHESIS/PURPOSE

The present study was designed to evaluate the cytotoxic effect and mode of action of a natural pentacyclic triterpenoid, celastrol, on cisplatin-resistant NPC cells.

RESULTS

Study results revealed that celastrol treatment significantly reduced the viability of NPC cells in dose and time dependent manners, as compared to untreated control cells. The cytotoxic effect of celastrol was mediated by cell cycle arrest at G2/M phase and induction of intrinsic and extrinsic apoptotic pathways. With further analysis, we observed that celastrol-induced activation of caspases was accompanied by increased phosphorylation of MAPK pathway proteins, p38, ERK1/2.

CONCLUSION

Taken together, our observation provides a novel insight on use of a natural plant product, celastrol, in the management of chemoresistant NPC.

Coronarin D induces apoptotic cell death through the JNK pathway in human hepatocellular carcinoma

Coronarin D, a diterpene derived from the rhizomes of Hedychium coronarium, has been used to treat inflammatory diseases. Coronarin D can exert strong anticancer effects through cell growth prevention and cell cycle arrest in many cancer cells. In this study, we investigated the molecular mechanism through which coronarin D suppresses cell proliferation and triggers cell death in human hepatocellular carcinoma (HCC) cells. Treatment of Huh7 and Sk-hep-1 cells with coronarin D resulted in a significantly increased loss of mitochondrial membrane potential, leading to the cleavage and activation of caspase-9, caspase-8, and caspase-3 and changes in Bax, Bcl-2, and Bcl-xL protein levels. Coronarin D significantly induced autophagy by increasing the expression of Beclin-1 and LC3-II and reducing the expression of p62. Moreover, Huh7 and Sk-hep-1 cells exposed to coronarin D had decreased expression of phosphorylated AKT, p38, and ERK and increased expression of phosphorylated JNK. Exposure of cells to the JNK-specific inhibitor SP600125 attenuated the apoptotic effects of coronarin D. Taken together, this is the first study to report that coronarin D may effectively inhibit cell growth through apoptosis. We have provided evidence indicating that coronarin D induces cell death through the upregulation of JNK mitogen-activated protein kinases in human HCC cells.

Glabridin induces apoptosis and cell cycle arrest in oral cancer cells through the JNK1/2 signaling pathway

Glabridin, a flavonoid extracted from licorice (Glycyrrhiza glabra), possesses various biological properties, including anticancer activities. However, the effect of glabridin on oral cancer cell apoptosis and the underlying molecular mechanisms has not been elucidated. In this study, we demonstrated that glabridin treatment significantly inhibits cell proliferation in human oral cancer SCC-9 and SAS cell lines. Flow cytometric assays demonstrated that glabridin induced several features of apoptosis, such as sub-G1 phase cell increase and phosphatidylserine externalization. Furthermore, glabridin induced apoptosis dose-dependently in SCC-9 cells through caspase-3, -8, and -9 activation and poly (ADP-ribose) polymerase cleavage. Moreover, glabridin increased the phosphorylation of the extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase (JNK) pathways in a dose-dependent manner. Moreover, the inhibition of the JNK1/2 inhibitor significantly reversed the glabridin-induced activation of the caspase pathway. In conclusion, our findings suggest that glabridin induces oral cancer cell apoptosis through the JNK1/2 pathway and is a potential therapeutic agent for oral cancer.

A naturally occuring triterpene saponin ardisiacrispin B displayed cytotoxic effects in multi-factorial drug resistant cancer cells via ferroptotic and apoptotic cell death

INTRODUCTION

Multidrug resistance of cancer cells constitutes a serious problem in chemotherapy and a challenging issue in the discovery of new cytotoxic drugs. Many saponins are known to display anti-cancer effects. In this study, the cytotoxicity and the modes of action of a naturally occuring oleanane-type tritepene saponin, ardisiacrispin B isolated from the fruit of Ardisia kivuensis Taton (Myrsinaceae) was evaluated on a panel of 9 cancer cell lines including various sensitive and drug-resistant phenotypes.

METHODS

Resazurin reduction assay was used to evaluate cytotoxicity and ferroptotic cell death of samples; caspase-Glo assay was used to detect the activation of caspases in CCRF-CEM leukemia cells. Flow cytometry was used for cell cycle analysis and detection of apoptotic cells by annexin V/PI staining, analysis of mitochondrial membrane potential (MMP) and measurement of reactive oxygen species (ROS).

RESULTS

Ardisiacrispin B displayed significant cytotoxic effects in the 9 tested cancer cell lines with IC₅₀ values below 10 µM. The IC₅₀ values ranges were 1.20 µM (towards leukemia CCRF-CEM cells) to 6.76 µM [against heptocarcinoma HepG2 cells] for ardisiacrispin B and 0.02 µM (against CCRF-CEM cells) to 122.96 µM (against resistant CEM/ADR5000 leukemia cells) for doxorubicin. Collateral sensitivity of resistant HCT116p53^-/- colon adenocarcinoma cells to ardisiacripsin B was observed. Ardisiacrispin B induced apoptosis in CCRF-CEM cells via activation of inititator caspases 8 and 9 and effector caspase 3/7, alteration of MMP and increase in ROS production. Ferroptosis also contributed to the cytotoxicity of ardisiacrispin B.

CONCLUSIONS

The studied oleanane-type triterpene saponin is a good cytotoxic molecule that deserve more detailed exploration in the future, to develop novel cytotoxic drugs to combat both sensitive and drug-resistant cancers.

Non-apoptotic cell death in malignant tumor cells and natural compounds

Traditional cancer therapy is mainly targeting on enhancing cell apoptosis, however, it is well established that many cancer cells are chemo-resistant and defective in apoptosis induction. Therefore, it may have important therapeutic implications to exploit some novel natural compounds based on non-apoptotic programmed cell death. Currently, accumulating evidence shows that the compounds from nature source can induce non-apoptotic programmed cell death in cancer cells, and therefore these natural compounds have gained a great promise for the future anticancer therapeutics. In this review, we will concentrate our efforts on the latest developments regarding major forms of non-apoptotic programmed cell death--autophagic cell death, necroptosis, ferroptosis, pyroptosis, glutamoptosis and exosome-associated cell death. Our increased understanding of the role of natural compounds in regulating non-apoptotic programmed cell death will hopefully provide prospective strategies for cancer therapy.

Isoaaptamine Induces T-47D Cells Apoptosis and Autophagy via Oxidative Stress

Aaptos is a genus of marine sponge which belongs to Suberitidae and is distributed in tropical and subtropical oceans. Bioactivity-guided fractionation of Aaptos sp. methanolic extract resulted in the isolation of aaptamine, demethyloxyaaptamine, and isoaaptamine. The cytotoxic activity of the isolated compounds was evaluated revealing that isoaaptamine exhibited potent cytotoxic activity against breast cancer T-47D cells. In a concentration-dependent manner, isoaaptamine inhibited the growth of T-47D cells as indicated by short-(MTT) and long-term (colony formation) anti-proliferative assays. The cytotoxic effect of isoaaptamine was mediated through apoptosis as indicated by DNA ladder formation, caspase-7 activation, XIAP inhibition and PARP cleavage. Transmission electron microscopy and flow cytometric analysis using acridine orange dye indicated that isoaaptamine treatment could induce T-47D cells autophagy. Immunoblot assays demonstrated that isoaaptamine treatment significantly activated autophagy marker proteins such as type II LC-3. In addition, isoaaptamine treatment enhanced the activation of DNA damage (γH2AX) and ER stress-related proteins (IRE1 α and BiP). Moreover, the use of isoaaptamine resulted in a significant increase in the generation of reactive oxygen species (ROS) as well as in the disruption of mitochondrial membrane potential (MMP). The pretreatment of T-47D cells with an ROS scavenger, N-acetyl-l-cysteine (NAC), attenuated the apoptosis and MMP disruption induced by isoaaptamine up to 90%, and these effects were mediated by the disruption of nuclear factor erythroid 2-related factor 2 (Nrf 2)/p62 pathway. Taken together, these findings suggested that the cytotoxic effect of isoaaptamine is associated with the induction of apoptosis and autophagy through oxidative stress. Our data indicated that isoaaptamine represents an interesting drug lead in the war against breast cancer.

Mechanism of NF-κB signaling pathway and autophagy in the regulation of osteoblast differentiation

OBJECTIVE

The objective of the present work was to investigate a possible mechanism of NF-κB signaling pathway and autophagy in the regulation of osteoblast differentiation, and provide experimental basis for the study of tooth eruption disorder.

METHODS

Mouse osteoblast-like (MC3T3-E1) cells were inoculated with a cell density of 70%. According to the grouping experimental design, Western blot and monodansylcadaverine (MDC) detection were conducted after dosing for 24 h. The cells were divided into the following five groups: blank control group; 6.25 µg/mL SN50 group; 12.5 µg/mL SN50 group; 25 µg/mL SN50 group and 50 µg/mL SN50 group.

RESULTS

Western blot analysis revealed that the expression of LC3 protein was present in the blank control group; 6.25 µg/mL SN50 group; 12.5 µg/mL SN50 group and 50 µg/mL SN50 group, with no significant differences among these groups. However, the expression of LC3 protein was significantly lower in the 25 µg/mL SN50 group. MDC detection showed that, in the blank control group; 6.25 µg/mL SN50 group; 12.5 µg/mL SN50 group and 50 µg/mL SN50 group, there was obvious green fluorescence in the cytoplasm of the osteoblasts. However, in the 25 µg/mL SN50 group, it was found that there were significantly fewer green fluorescent particles.

CONCLUSION

The osteoblast itself had a strong function of autophagy. The appropriate concentration of SN50 in blocking the NF-κB pathway of the osteoblast was associated with the obvious inhibition of autophagy. However, the relationship between NF-κB signaling pathway and autophagy in the process of tooth eruption requires further study.

Nimbolide induces apoptosis in human nasopharyngeal cancer cells

Nasopharyngeal carcinoma (NPC), a tumor arising from epithelial cells that cover the surface and line the nasopharynx, is a rare malignancy worldwide but is prevalent in certain geographical areas, such as Southern Asia (Taiwan, Hong Kong, Singapore, Malaysia, and Southern China) and North Africa. Despite advances in diagnostic techniques and improvements in treatment modalities, the prognosis of NPC remains poor. Therefore, an effective chemotherapy regimen that enhances tumor sensitivity to chemotherapeutics is urgently required. Nimbolide, derived from Azadirachta indica, has a wide range of beneficial effects, including anti-inflammatory and anticancer properties. The present study evaluated the antitumor activity of nimbolide in NPC cells and its underlying mechanisms. Our results revealed that the treatment of HONE-1 cells with nimbolide potently inhibited cell viability. Moreover, nimbolide led to cell cycle arrest, which subsequently activated caspase-3, -8, and -9 and poly (ADP-ribose) polymerase to induce cell apoptosis. Moreover, nimbolide induced Bik, Bax, and t-Bid expression in HONE-1 cells. The results indicated that nimbolide induces apoptosis through the modulation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) pathways. Nimbolide induces apoptosis in human NPC cells and is a potential chemopreventive agent against NPC proliferation. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 2085-2092, 2017.

Ginkgo biloba exocarp extracts induces autophagy in Lewis lung cancer cells involving AMPK / mTOR / p70S6k signaling pathway

OBJECTIVES

Ginkgo biloba L. is called a living fossil plant, and could be used for the treatment of cancer thousands of years ago in China. The extracts prepared from the Ginkgo biloba exocarp (Ginkgo biloba exocarp extracts, GBEE) has a significant anti-cancer effect. Autophagy plays an important role in the occurrence and development of cancer as programmed cell death (PCD) type II. Thus it would be interesting to study the effects and mechanisms of GBEE inducing autophagy in Lewis lung cancer (LLC) cells.

METHODS

MTT method was used to detect the inhibitory effect of GBEE on LLC cells. Monodansylcadaverine (MDC) staining method was applied to observe the formation of acidic vacuoles in cells. The ultrastructure of LLC cells was observed using transmission electron microscope (TEM) to confirm the formation of autophagosomes. Quantify reverse transcription-polymerase chain reaction (qRT-PCR) was used to detect the mRNA levels of Beclin1 and Atg5. Western Blot was used to detect the protein levels of Beclin1, Atg5, LC3I/II, p-AMPK, AMPK, p-mTOR, mTOR, p-p70S6k and p70S6K in LLC cells.

RESULTS

GBEE (5-160μg/mL) inhibited the proliferation of LLC cells in vitro with the half maximal inhibitory concentration (IC50) value of 161.26μg/mL. The formation and activation of acidic vacuoleswere increased by the action of GBEE (10, 20 and 40μg/mL) on LLC cells. The autophagosomes were also increased. Meanwhile, it up-regulated both the mRNA and protein levels of Beclin1 and Atg5. The ratio of LC3-I/LC3-II protein was down-regulated. In addition, the protein level of p-AMPK was increased, and the p-mTOR and p-p70S6K was decreased. But the AMPK, mTOR and p70S6K proteins were not significantly changed.

CONCLUSIONS

The inhibitory effect of GBEE on LLC is associate with inducing autophagy in LLC cells, which may be closely relevant to the regulation of AMPK/mTOR/p70S6k signaling pathways.

Role of JNK signaling in oral cancer: A mini review

JNKs (c-Jun N-terminal kinases) belong to mitogen-activated protein kinases' family and become activated by several growth factors, stress, radiation, and other extracellular signals. In turn, JNK activation results in phosphorylation of downstream molecules involved in many normal cellular processes. Nevertheless, recent data have linked JNK signaling with several pathological conditions, including neurodegenerative diseases, inflammation, and cancer. The role of JNK in cancer remains controversial. Initially, JNK was thought to play a rather oncosuppressive role by mediating apoptosis in response to stress stimuli, inflammatory, or oncogenic signals. However, a number of studies have implicated JNK in malignant transformation and tumor growth. The contradictory functions of JNK in cancer may be due to the diversity of JNK upstream and downstream signaling and are under intensive investigation. This review summarizes current literature focusing on the significance of JNK pathway in cancer development and progression, particularly addressing its role in oral cancer. Understanding the complexity of JNK signaling has the potential to elucidate important molecular aspects of oral cancer, possibly leading to development of novel and individualized therapeutic strategies.