Volatile Oil of Acori Graminei Rhizoma-Induced Apoptosis and Autophagy are dependent on p53 Status in Human Glioma Cells

Recent insights into autophagy and metals/nanoparticles exposure

Some anthropogenic pollutants, such as heavy metals and nanoparticles (NPs), are widely distributed and a major threat to environmental safety and public health. In particular, lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As), and mercury (Hg) have systemic toxicity even at extremely low concentrations, so they are listed as priority metals in relation to their significant public health burden. Aluminum (Al) is also toxic to multiple organs and is linked to Alzheimer's disease. As the utilization of many metal nanoparticles (MNPs) gradually gain traction in industrial and medical applications, they are increasingly being investigated to address potential toxicity by impairing certain biological barriers. The dominant toxic mechanism of these metals and MNPs is the induction of oxidative stress, which subsequently triggers lipid peroxidation, protein modification, and DNA damage. Notably, a growing body of research has revealed the linkage between dysregulated autophagy and some diseases, including neurodegenerative diseases and cancers. Among them, some metals or metal mixtures can act as environmental stimuli and disturb basal autophagic activity, which has an underlying adverse health effect. Some studies also revealed that specific autophagy inhibitors or activators could modify the abnormal autophagic flux attributed to continuous exposure to metals. In this review, we have gathered recent data about the contribution of the autophagy/mitophagy mediated toxic effects and focused on the involvement of some key regulatory factors of autophagic signaling during exposure to selected metals, metal mixtures, as well as MNPs in the real world. Besides this, we summarized the potential significance of interactions between autophagy and excessive reactive oxygen species (ROS)-mediated oxidative damage in the regulation of cell survival response to metals/NPs. A critical view is given on the application of autophagy activators/inhibitors to modulate the systematic toxicity of various metals/MNPs.

Natural Products as Anticancer Agents: Current Status and Future Perspectives

Natural products have been an invaluable and useful source of anticancer agents over the years. Several compounds have been synthesized from natural products by modifying their structures or by using naturally occurring compounds as building blocks in the synthesis of these compounds for various purposes in different fields, such as biology, medicine, and engineering. Multiple modern and costly treatments have been applied to combat cancer and limit its lethality, but the results are not significantly refreshing. Natural products, which are a significant source of new therapeutic drugs, are currently being investigated as potential cytotoxic agents and have shown a positive trend in preclinical research and have prompted numerous innovative strategies in order to combat cancer and expedite the clinical research. Natural products are becoming increasingly important for drug discovery due to their high molecular diversity and novel biofunctionality. Furthermore, natural products can provide superior efficacy and safety due to their unique molecular properties. The objective of the current review is to provide an overview of the emergence of natural products for the treatment and prevention of cancer, such as chemosensitizers, immunotherapeutics, combinatorial therapies with other anticancer drugs, novel formulations of natural products, and the molecular mechanisms underlying their anticancer properties.

Network Pharmacology-Based Study on the Active Component and Mechanism of the Anti-Gastric-Cancer Effect of Herba Sarcandrae

Background

Herba Sarcandrae is used in the clinical practice of traditional Chinese medicine to deal with gastric cancer. However, there are few studies on its precise mechanism.

Method

In this study, a network pharmacological approach was utilized to construct a molecular/target/pathway molecular regulatory network for the anti-gastric-cancer effect of Herba Sarcandrae. The active components of Herba Sarcandrae and their potential mechanisms were explored. Chemical components of the Herba Sarcandrae were identified through a database, and they were evaluated and screened based on oral bioavailability and drug similarity.

Results

Genes related to gastric cancer were found in the Gene Expression Omnibus (GEO) database, and gene targets related to anti-gastric-cancer were chosen by comparison. Using annotation, visualization, and a comprehensive discovery database, the function and related pathways of target genes were analyzed and screened. Cytoscape software was utilized to construct a component/target/pathway network for the antitumor effect of Herba Sarcandrae. Finally, 6 drug ingredients and 29 target genes related to gastric cancer were detected. IL-17 signaling pathway, NF-kappa B signaling pathway, and other signaling pathways were significantly enriched. Many signaling pathways that directly act on tumors and indirect pathways inhibit the development of gastric cancer.

Conclusion

This study provides a scientific basis for further elucidating the mechanism of the anti-gastric-cancer effect of Herba Sarcandrae.

P53/miR-154 Pathway Regulates the Epithelial-Mesenchymal Transition in Glioblastoma Multiforme Cells by Targeting TCF12

PURPOSE

Glioblastoma multiforme (GBM) is an aggressive brain tumor with a rather short survival time. Mutation of p53 has been observed and reported to play critical roles in the progression of GBM. However, the pathological mechanisms are still unclear. This study was designed to identify the role of miR-154 in mediating the biological functions of p53 in glioblastoma multiforme.

METHODS

In the current study, the expression of miR-154 in GBM tissue samples and cell lines with wt-p53 or mutant p53 was evaluated. The functions of miR-154 in tumor migration, invasion and epithelial-mesenchymal transition were analyzed in vitro. A luciferase reporter assay was used to identify the target of miR-154.

RESULTS

We found that expression of miR-154 was much lower in patient tissues with mutant p53. Further study revealed that p53 was a transcription factor of miR-154 and that the R273H mutation led to its inactivation. In addition, overexpression of miR-154 remarkably suppressed cell migration, invasion and EMT in vitro and tumor growth in vivo. Moreover, TCF12 was proven to be a direct target of miR-154, and the tumor suppressive effect of miR-154 was reversed by TCF12.

CONCLUSION

Overall, miR-154, which was regulated by wt-p53, inhibited migration, invasion and EMT of GBM cells by targeting TCF12, indicating that miR-154 may act as a biomarker and that the p53/miR-154/TCF12 pathway could be a potential therapeutic target for GBM.

Towards DNA-damage induced autophagy: A Boolean model of p53-induced cell fate mechanisms

How a cell determines a given phenotype upon damaged DNA is an open problem. Cell fate decisions happen at cell cycle checkpoints and it is becoming clearer that the p53 pathway is a major regulator of cell fate decisions involving apoptosis or senescence upon DNA damage, especially at G1/S. However, recent results suggest that this pathway is also involved in autophagy induction upon DNA damage. To our knowledge, in this work we propose the first model of the DNA damage-induced G1/S checkpoint contemplating the decision between three phenotypes: apoptosis, senescence, and autophagy. The Boolean model is proposed based on experiments with U87 glioblastoma cells using the transfection of miR-16 that can induce a DNA damage response. The wild-type case of the model shows that DNA damage induces the checkpoint and the coexistence of the three phenotypes (tristable dynamics), each with a different probability. We also predict that the positive feedback involving ATM, miR-16, and Wip1 has an influence on the tristable state. The model predictions were compared to experiments of gain and loss of function in other three different cell lines (MCF-7, A549, and U2OS) presenting agreement. For p53-deficient cell lines such as HeLa, H1299, and PC-3, our model contemplates the experimental observation that the alternative AMPK pathway can compensate this deficiency. We conclude that at the G1/S checkpoint the p53 pathway (or, in its absence, the AMPK pathway) can regulate the induction of different phenotypes in a stochastic manner in the U87 cell line and others.

Sinensetin Induces Autophagic Cell Death through p53-Related AMPK/mTOR Signaling in Hepatocellular Carcinoma HepG2 Cells

Sinensetin (SIN) has been reported to exhibit anti-inflammatory and anti-cancer activity. However, the cellular and molecular mechanism by which SIN promotes hepatocellular carcinoma (HCC) cell death remains unclear. In the present study, we investigated the induction of cell death by SIN and its underlying mechanism in HepG2 cells, an HCC cell line. We found that SIN significantly induced cell death in HepG2 cells, whereas the proliferation rate of Thle2, human liver epithelial cells, was unaffected by SIN. SIN-treated HepG2 cells were not affected by apoptotic cell death; instead, autophagic cell death was induced through the p53-mediated AMPK/mTOR signaling pathway. Inhibition of p53 degradation led to both autophagy and apoptosis in HepG2 cells. p53 translocation led to SIN-induced autophagy, whereas p53 translocation inhibited SIN-induced apoptosis. However, SIN showed apoptosis in the p53-mutant Hep3B cell line. Molecular docking simulation of the p53 core domain showed effective binding with SIN, which was found significant compared with the known p53 activator, RITA. Collectively, these data suggest that SIN may be a potential anti-cancer agent targeting autophagic cell death in human liver cancer.

AGEs induces apoptosis and autophagy via reactive oxygen species in human periodontal ligament cells

The apoptosis of human periodontal ligament cells (HPDLCs) may be an important factor of the negative effect of advanced glycation end products (AGEs) on the periodontal tissue of diabetic patients. However, the pathways or potential effects of apoptosis in AGEs-treated HPDLCs have not been fully elucidated. Autophagy is closely related to apoptosis. Herein, we investigated the potential mechanism of apoptosis and autophagy in HPDLCs treated with AGEs via an in vitro model. We found that AGEs-treated HPDLCs showed a time- and concentration-dependent reduction in the cell survival rate. The mitochondrial-dependent apoptosis was induced in AGEs-treated HPDLCs, as confirmed by the mitochondrial membrane potential depolarization, decreased Bcl-2 expression, increased Bax expression, and increased caspase-3 and PARP cleavage. Autophagy was also induced in AGEs-treated HPDLCs, as indicated by the conversion of LC3-II/LC3-I and the presence of autophagosomes. Interestingly, our study results suggested that apoptosis and autophagy were related to reactive oxygen species (ROS) production. In addition, AGEs-induced autophagy acted as a latent factor in decreasing the generation of ROS in HPDLCs and protecting against the AGEs-induced apoptosis. In summary, our study shows that ROS are essential in AGEs-induced HPDLCs apoptosis and autophagy, which may be a molecular mechanism for the repairment of ROS-induced damage in HPDLCs treated with AGEs to promote cell survival. The present study might provide new insights into the therapeutic targeting of HPDLCs autophagy, which could be an additional strategy for periodontitis in patients with diabetes mellitus.

Molecular mechanisms of apoptosis and autophagy elicited by combined treatment with oridonin and cetuximab in laryngeal squamous cell carcinoma

Combined oridonin (ORI), a natural and safe kaurene diterpenoid isolated from Rabdosia rubescens, and cetuximab (Cet), an anti-EGFR monoclonal antibody, have been reported to exert synergistic anti-tumor effects against laryngeal squamous cell carcinoma (LSCC) both in vitro and in vivo by our group. In the present study, we further found that ORI/Cet treatment not only resulted in apoptosis but also induced autophagy. AMPK/mTOR signaling pathway was found to be involved in the activation of autophagy in ORI/Cet-treated LSCC cells, which is independent of p53 status. Additionally, chromatin immunoprecipitation (ChIP) assay showed that ORI/Cet significantly increased the binding NF-κB family member p65 with the promotor of BECN 1, and p65-mediated up-regulation of BECN 1 caused by ORI/Cet is coupled to increased autophagy. On the other hand, we demonstrated that either Beclin 1 SiRNA or autophagy inhibitors could increase ORI/Cet induced-apoptosis, indicating that autophagy induced by combination of the two agents plays a cytoprotective role. Interestingly, 48 h after the combined treatment, autophagy began to decrease but apoptosis was significantly elevated. Our findings suggest that autophagy might be strongly associated with the antitumor efficacy of ORI/Cet, which may be beneficial to the clinical application of ORI/Cet in LSCC treatment.

Saikosaponin-d Increases the Radiosensitivity of Hepatoma Cells by Adjusting Cell Autophagy

Radiotherapy for liver cancer can affect the level of autophagy in cells, and effective autophagy regulation can increase the radiosensitivity of liver cancer cells.Saikosaponin-d (SSd) is an effective active ingredient extracted from traditional Chinese medicine Bupleurum. We have confirmed previously in vitro and in vitro experiments that SSd can significantly induce apoptosis of liver cancer cells, increase the radiosensitivity of liver cancer cells.This study explored the role of autophagy in SSd-mediated radiosensitivity of liver cancer cells. MTT and clone formation experiments showed that radiation can inhibit the proliferation of hepatoma cells and reduce the colony formation of hepatoma cells. After the addition of SSd, the inhibitory effect of radiation on the proliferation and clonal formation of hepatoma cells was further enhanced. However, the addition of the autophagy inhibitor chloroquine or mTOR agonist can partially reverse the inhibitory effect of the combined treatment of SSd with radiation on the proliferation of hepatoma cells. Similarly, transmission electron microscopy and laser confocal microscopy showed that after the addition of SSd, the number of radiation-induced autophagosomes increased significantly in hepatoma cells and the intervention of mTOR agonist can reduce the formation of autophagosomes in hepatoma cells.In addition,Western blot analysis presented that radiation significantly increased LC3-II levels. Especially when SSd is added, LC3-II levels is further increased. Our data indicate that SSd can inhibit the growth of liver cancer cells and enhance cell radiosensitivity by inducing autophagy formation.

Ochratoxin A induces cytoprotective autophagy via blocking AKT/mTOR signaling pathway in PK-15 cells

Ochratoxin A (OTA) could cause a variety of toxicological effects especially nephrotoxicity in animals and humans. Autophagy is a highly conserved metabolic process that plays an important role in the maintenance of cellular homeostasis under stress. However, the role of autophagy in OTA-induced nephrotoxicity is unknown. In the present study, we demonstrated that OTA treatment at 2.0-8.0 μM could increase cytotoxicity of PK-15 cells by inducing apoptosis as shown by the increased Annexin V/PI staining, increased caspase-3 and PARP cleavage and increased apoptotic nuclei. Meantime, autophagy was triggered when OTA was administrated, as indicated by markedly increased expressions of LC3-II, ATG5 and Beclin-1, accumulation of GFP-LC3 dots and increased double- or single-membrane vesicles. OTA treatment decreased p-AKT and p-mTOR activities, and OTA-induced autophagy was inhibited when insulin was applied. Furthermore, OTA treatments with autophagy inhibitors (3-methyladenine or chloroquine) or knockdown of autophagy-related genes (ATG5 or Beclin-1) resulted in significantly reduced autophagy level and enhanced cytotoxicity. In conclusion, OTA induces cytoprotective autophagy against its cytotoxicity and inactivation of AKT/mTOR axis plays a critical role in autophagy induction.

Triptolide induces protective autophagy and apoptosis in human cervical cancer cells by downregulating Akt/mTOR activation

Triptolide exhibits immunosuppressive, anti-inflammatory, antifertility and antineoplastic functions. However, the anticancer effect of triptolide on cervical cancer and the underlying mechanism remains to be fully understood. The present study assessed the mechanisms underlying the effect of triptolide on the viability and apoptosis of human cervical cancer cells. SiHa cells were treated with 12.5-100.0 nM triptolide for 12, 24 or 48 h. The present study demonstrated that triptolide inhibited viability and induced apoptosis in SiHa cells time- and dose-dependently. Furthermore, treatment with triptolide promoted autophagy and activated microtubule associated protein 1 light chain 3 α expression in SiHa cells. Triptolide treatment suppressed the expression of phosphorylated (p)-protein kinase B (Akt), p-mechanistic target of rapamycin (mTOR), and p-p70S6K, activated the expression of p-p38, mitogen-activated protein kinase (MAPK) and p53 and inhibited the expression of p-forkhead box O3 (Foxo3a) in SiHa cells. These results suggested that triptolide induces protective autophagy, suppresses cell viability and promotes apoptosis in human cervical cancer cells by inducing the autophagy-targeting phosphoinositide 3-kinase/Akt/mTOR, p38, MAPK, p53 and Foxo3a pathways.

β-Asarone Induces Apoptosis and Cell Cycle Arrest of Human Glioma U251 Cells via Suppression of HnRNP A2/B1-Mediated Pathway In Vitro and In Vivo

HnRNP A2/B1 has been found to be an oncogenic protein strongly related to the growth of human glioma cells. Herein, β-asarone, the main component in the volatile oil of Acori tatarinowii Rhizoma, inhibited the cell viability, proliferation, and colony formation ability of U251 cells. Moreover, β-asarone induced apoptosis and cell cycle arrest at the G1 phase. Notably, β-asarone suppressed the expression of hnRNP A2/B1 and hnRNPA2/B1 overexpression remarkably reversed β-asarone-mediated apoptosis and cell cycle arrest. Importantly, β-asarone promoted the alternative splicing of Bcl-x by enhancing the ratio of Bcl-xS/Bcl-xL. Meanwhile, hnRNPA2/B1 overexpression mitigated the promoting effect of β-asarone on the alternative splicing of Bcl-x. β-asarone also regulated the level of the key proteins involved in the death receptor pathway and mitochondrial apoptosis pathway. Additionally, β-asarone modulated the cell cycle-related proteins p21, p27, Cdc25A, cyclin D, cyclin E, and CDK2. Finally, β-asarone inhibited tumor growth and induced apoptosis in nude mice bearing U251 tumor xenografts. β-asarone also suppressed the hnRNP A2/B1 expression, enhanced the expression of cleaved-caspase 3 and p27 and the ratio of Bcl-xS/Bcl-xL, and reduced the expression of CDK2 in U251 xenografts. Together, β-asarone-induced apoptosis and cell cycle arrest of U251 cells may be related to the suppression of hnRNPA2/B1-mediated signaling pathway.

Tripartite motif 31 promotes resistance to anoikis of hepatocarcinoma cells through regulation of p53-AMPK axis

Anoikis-resistance is an essential feature of cancer cells to obtain successful metastasis, whereas the molecular mechanism involved in this process of hepatocellular carcinoma (HCC) cells is not fully understood. Here we demonstrated that tripartite motif-containing (TRIM) 31, a new member of the TRIM family, was significantly upregulated in the anchorage-deprived HCC cells compared with their attached counterpart. When we blocked TRIM31 expression by its specific interference RNAs, the anoikis-resistance of HCC cells was significantly reversed. We further verified that overactivation of AMPK pathway was responsible for TRIM31-mediated resistance to anoikis of HCC cells; and TRIM31 could directly target p53, the upstream suppressor of AMPK pathway, and mediate K48-linked ubiquitous degradation of p53 in a RING-domain-dependent way. Therefore we demonstrated that TRIM31 promoted anoikis-resistance by targeting p53 for degradation and subsequently overactivating AMPK pathway. Thus our study defined for the first time the role of TRIM31 in the anoikis-resistant process of HCC cells， and it may pave a new avenue for manipulation of metastatic cancer by targeting TRIM31.

β-Asarone Inhibits Invasion and EMT in Human Glioma U251 Cells by Suppressing Splicing Factor HnRNP A2/B1

β-asarone, the main component in the volatile oil of Acori tatarinowii Rhizoma, has been found to possess antitumor activity. However, its effect and mechanisms against tumor invasion and epithelial–mesenchymal transition (EMT) are still unclear. In this study, no or less cytotoxicity was caused by β-asarone within 0–120 μM in human glioma U251 cells for 48 h. β-asarone (30 and 60 μM) inhibited the migration of U251 cells in the wound healing assay, suppressed the invasion of U251 cells in the Boyden chamber invasion assay, and inhibited the adhesion of U251 cells onto the Matrigel. Moreover, β-asarone suppressed EMT with the up-regulation of E-cadherin and the down-regulation of vimentin. HnRNP A2/B1, a well-characterized oncogenic protein, was shown at a high basal level in U251 cells and β-asarone reduced hnRNP A2/B1 expression in a concentration and time-dependent way. Importantly, hnRNP A2/B1 overexpression significantly counteracted the inhibition of β-asarone on the migration, invasion, and adhesion of U251 cells and reversed the modulation of EMT markers by β-asarone. Additionally, β-asarone decreased the MMP-9 and p-STAT3 in U251 cells, which was also reversed by hnRNP A2/B1 overexpression. Together, our results suggest that hnRNP A2/B1 may be a potential molecular target underlying the inhibitory effect of β-asarone on invasion and EMT in glioma cells.

A novel polysaccharide derived from algae extract inhibits cancer progression via JNK, not via the p38 MAPK signaling pathway

Cancer has long been one of the most malignant diseases worldwide. Processes in cancer cells are often mediated by Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (p38 MAPK) and other signaling pathways. Traditional therapies are often problematic. Recently, a novel polysaccharide derived from algae extract was investigated due to the increasing interest in biological activities of compounds from marine organisms. The effect of this novel polysaccharide on human MKN45 gastric carcinoma cells was determined previously. The current aimed to determine whether the polysaccharide affects other types of cancer, and the deeper mechanisms involved in the process. Human MCF-7 breast cancer cells were used to investigate the novel polysaccharide for its role in the cell growth and migration, and determine the mechanisms affected. MTT assay, nuclear staining and fluorescence activated cell sorting analysis demonstrated that the novel polysaccharide reduced the viability of MCF-7 cells by inducing cell apoptosis and arresting the cells at G2/M phase. Results of western blot analysis demonstrated that phosphorylation of JNK and expression of p53, caspase-9 and caspase-3 were upregulated in the polysaccharide-treated MCF-7 cells. SP600125, an inhibitor of JNK, maintained MCF-7 cell viability, prevented cell apoptosis and cycle arrest, and downregulated the polysaccharide-induced protein phosphorylation/expression. However, a migration assay demonstrated that the novel polysaccharide did not change the migration of MCF-7 cells, as well as the expression of p38 MAPK, and matrix metalloproteinase-9 and -2. Taken together, the current study demonstrated that the novel polysaccharide suppressed cancer cell growth, induced cancer cell apoptosis and cell cycle arrest via JNK signaling, but had no effect on cancer cell migration and p38 MAPK signaling.

Retigabine ameliorates acute stress-induced impairment of spatial memory retrieval through regulating USP2 signaling pathways in hippocampal CA1 area

Acute stress could trigger maladaptive changes associated with stress-related cognitive and emotional deficits. Dysfunction of ion channel or receptor in the hippocampal area has been linked to the cognitive deficits induced by stress. It is known that Kv7 channel openers, including FDA-approved drug retigabine, show cognitive protective efficacy. However, the underlying molecular mechanisms remain elusive. Here we showed that exposing adult male rats to acute stress significantly impaired the spatial memory, a cognitive process controlled by the hippocampus. Concomitantly, significantly reduced AMPA receptor expression was found in hippocampal CA1 area from acute stressed rats. This effect relied on the down-regulation of deubiquitinating enzyme USP2 and its upstream regulators (PGC-1α and β-catenin), and the subsequent enhancement of mTOR-related autophagy which is regulated by USP2. These findings suggested that acute stress dampened AMPA receptor expression by controlling USP2-related signaling, which caused the detrimental effect on hippocampus-dependent cognitive processes. We also found that retigabine alleviated acute stress-induced spatial memory retrieval impairment through adjusting the aberrance of USP2, its upstream regulators (PGC-1α, E4BP4 and β-catenin) and its downstream targets (mTOR, autophagy and GluA1). Our results have identified USP2 as a key molecule that mediates stress-induced spatial memory retrieval impairment, which provides a framework for new druggable targets to conceptually treat stress-associated cognitive deficits.

Review of Natural Product-Derived Compounds as Potent Antiglioblastoma Drugs

Common care for glioblastoma multiforme (GBM) is a surgical resection followed by radiotherapy and temozolomide- (TMZ-) based chemotherapy. Unfortunately, these therapies remain inadequate involving severe mortality and recurrence. Recently, new approaches discovering combinations of multiple inhibitors have been proposed along with the identification of key driver mutations that are specific to each patient. To date, this approach is still limited by the lack of effective therapy. Hopefully, novel compounds derived from natural products are suggested as potential solutions. Inhibitory effects of natural products on angiogenesis and metastasis and cancer suppressive effect of altering miRNA expression are provident discoveries. Angelica sinensis accelerates apoptosis by their key substances influencing factors of apoptosis pathways. Brazilin displays antitumor features by making influence on reactive oxygen species (ROS) intensity. Sargassum serratifolium, flavonoids, and so on have antimetastasis effect. Ficus carica controls miRNA that inhibits translation of certain secretory pathway proteins during the UPR. Serratia marcescens and patupilone (EPO 906) are physically assessed materials through clinical trials related to GBM progression. Consequently, our review puts emphasis on the potential of natural products in GBM treatment by regulating multiple malignant cancer-related pathway solving pending problem such as reducing toxicity and side effect.

MicroRNA-141-3p promotes glioma cell growth and temozolomide resistance by directly targeting p53

Glioblastoma multiforme is the most common primary malignancy in the brain and confers a uniformly poor prognosis. MicroRNAs have been shown to activate or inhibit tumorigenesis. Abnormalities in the p53 signaling pathway are found in various cancers and correlate with tumor formation. We examined the expression of microRNA-141-3p (miR-141-3p) in glioma of different grades by analysis of expression profiling databases and clinical specimens. Cell proliferation and flow cytometry assays were performed to evaluate the promotion of miR-141-3p in proliferation, cell cycle, apoptosis, and temozolomide resistance of glioblastoma cells in vitro. Bioinformatics analyses, luciferase reporter assays, and immunoblotting showed that p53 is a target gene of miR-141-3p. A significant inverse correlation was observed between expression of miR-141-3p and p53 in glioma and normal brain tissues (R²=0.506, P<0.0001). Rescue experiments indicated that overexpression of p53 significantly reversed the alterations in proliferation, cell cycle distribution, and temozolomide resistance measured by cell apoptosis induced by miR-141-3p overexpression. In an orthotopic mouse model of human glioma, inhibition of miRNA-141-3p reduced the proliferation and growth of glioma cells in the brain and significantly prolonged the survival of glioma-bearing mice. We suggest that miR-141-3p promotes glioblastoma progression and temozolomide resistance by altering p53 expression and therefore may serve as a new diagnostic marker and therapeutic target for glioma in the future.

GC-MS analysis of volatile compounds of Perilla frutescens Britton var. Japonica accessions: Morphological and seasonal variability

OBJECTIVE

To investigate the composition of volatile compounds in the different accessions of Perilla frutescens (P. frutescens) collected from various habitats of China and Japan.

METHODS

In the present study, the essential oil from the leaves of P. frutescens cultivars from China and Japan was extracted by hydro-distillation and the chemical composition and concentration of the volatile components present in the oils were determined by gas chromatography-mass spectrometry (GC-MS) analysis.

RESULTS

Among the volatile components, the major proportion was of perilla ketone, which was followed by elemicin and beta-caryophyllene in the Chinese Perilla cultivars. The main component in the oil extracted from the Japanese accessions was myristicin, which was followed by perilla ketone and beta-caryophyllene. We could distinguish seven chemotypes, namely the perilla ketone (PK) type, perilla ketone, myristicin (PM) type, perilla ketone, unknown (PU) type, perilla ketone, beta-caryophyllene, myristicine (PB) type, perilla ketone, myristicin, unknown (PMU) type, perilla ketone, elemicine, myristicin, beta-caryophyllene (PEMB) type, and the perilla ketone, limonene, beta-cryophyllene, myristicin (L) type. Most of the accessions possessed higher essential oil content before the flowering time than at the flowering stage. The average plant height, leaf length, leaf width of the Chinese accessions was higher than those of the Japanese accessions.

CONCLUSION

The results revealed that the harvest time and geographical origin caused polymorphisms in the essential oil composition and morphological traits in the Perilla accessions originating from China and Japan. Therefore, these chemotypes with desirable characters might be useful for industrial exploitation and for determining the harvest time.

Lithium enhances the antitumour effect of temozolomide against TP53 wild-type glioblastoma cells via NFAT1/FasL signalling

Background:

We previously showed that activation of the nuclear factor of activated T cells (NFAT)1/Fas ligand (FasL) pathway induces glioma cell death. Lithium (Li) is an inhibitor of glycogen synthase kinase (GSK)-3 that activates NFAT1/FasL signalling. Temozolomide (TMZ) inhibits GSK-3 and activates Fas in tumour protein (TP)53 wild-type (TP53wt) glioma cells. The present study investigated the combinational effects of TMZ and low-dose Li on TP53wt glioma cells.

Methods:

The combined effect of TMZ and Li was examined in TP53wt U87 and primary glioma cells and a mouse xenograft model.

Results:

Combination with 1.2 mM Li potentiated TMZ-induced cell death in TP53wt glioma cells, as determined by neurosphere formation and apoptosis assays. Temozolomide combined with Li treatment inhibited GSK-3 activation, promoted NFAT1 nuclear translocation and upregulated Fas/FasL expression. Targeted knockdown of NFAT1 expression blocked the induction of cell death by TMZ and Li via FasL inhibition. In vivo, combined treatment with TMZ and Li suppressed tumour growth and prolonged the survival of tumour-bearing mice. However, the combination of TMZ and Li did not produce a statistically significant effect in TP53mut glioma cells.

Conclusions:

Temozolomide combined with low-dose Li induces TP53wt glioma cell death via NFAT1/FasL signalling. This represents a potential therapeutic strategy for TP53wt glioma treatment.

CASC2c as an unfavorable prognosis factor interacts with miR-101 to mediate astrocytoma tumorigenesis

miR-101 has been suggested as a tumor suppressor, but the promoter methylation and loss of heterozygosity didn't contribute to its low expression in astrocytoma. We investigated the role of a new long non-coding RNA CASC2c binding with miR-101. High CASC2c was positively correlated with astrocytoma progression, and an unfavorable prognosis factor for patients. Knockdown CASC2c inhibited proliferation and tumorgenesis. Overexpression of CASC2c promotes the malignant characteristic of astrocytoma cells.CASC2c directly bound miR-101 and mediated pre-miR-101 processing into mature miR-101, and functions as a competitor of miR-101 target genes such as CPEB1. Patients who possessed both low CASC2c and high miR-101 had a longer survival than those of low CASC2c alone or high miR-101 alone. In summary, CASC2c plays the onco-RNA role in the tumorgenesis of astrocytoma by acting as a decoy miR-101 sponge. Combination of low expression of CASC2c and high expression of miR-101 has an important referential significance to evaluate the prognosis of patients.

Icaritin induces apoptotic and autophagic cell death in human glioblastoma cells

BACKGROUND

GBM represents the most aggressive type of glioma which is featured by extremely aggressive invasion and destructive malignancy with a high proliferation rate. The aim of this study was to investigate the in vitro anti-tumor effect of icaritin in human GBM cell line U87.

METHODS

The effect of icaritin on In vitro cell viability was determined by MTT assay and colony formation assay. The inducing effect of icaritin on cell cycle arrest, mitochondrial membrane potential loss, apoptosis, autophagy and intracellular ROS generation was assessed by flow cytometry. The apoptotic cell death was also confirmed by TUNEL assay. The expression levels of target or marker molecules were examined by western blot. The activity of caspase-3, -8 and -9 was detected with ELISA kit.

RESULTS

Our results showed that icaritin significantly induced both caspase-dependent apoptosis and autophagy in human GBM cell line U87. Additionally, our findings revealed that icaritin exerted anti-tumor effect by modulating Stat3 through generating ROS and subsequent activation of AMPK and inhibition of mTOR. Further investigation also showed that icaritin-induced autophagy served as a pro-death function and possibly contributed to icaritin-induced apoptosis.

CONCLUSION

Icaritin potently inhibit the cell growth of human GBM cell line U87 through inducing both caspase-dependent apoptosis and autophagy. Base on our findings, icaritin can be considered as a promising candidate therapeutic agent for treatment of GBM, though further studies are needed.

Inhibition of autophagy increased AGE/ROS-mediated apoptosis in mesangial cells

The aim of our study was to investigate the role of autophagy, a homeostatic process involved in the lysosomal degradation of damaged cell organelles and proteins, in regulating the survival of mesangial cells treated with advanced glycation end products (AGEs). In the present study, AGEs induced mitochondrial depolarization and led to mitochondrial-dependent apoptosis in mesangial cells, as shown by the loss of the mitochondrial membrane potential; increased Bax processing; increased Caspase-9, Caspase-3 and PARP cleavage; and decreased Bcl-2 expression. Meanwhile, AGEs also triggered autophagy flux in mesangial cells, as confirmed by the presence of autophagic vesicles, the conversion of LC3II/LC3I and the increase/decrease in Beclin-1/p62 expression. Interestingly, this study reported apparent apoptosis and autophagy that were dependent on reactive oxygen species (ROS) production. Scavenging ROS with N-acetyl-l-cysteine could prevent the appearance of the autophagic features and reverse AGE-induced apoptosis. Moreover, AGE-triggered mitophagy, which was confirmed by the colocalization of autophagosomes and mitochondria and Parkin translocation to mitochondria, played a potential role in reducing ROS production in mesangial cells. Additionally, inhibition of autophagy significantly enhanced AGE-induced cell apoptosis. Taken together, our data suggest that ROS were the mediators of AGE-induced mesangial cell apoptosis and that autophagy was likely to be the mechanism that was triggered to repair the ROS-induced damage in the AGE-treated cells and thereby promote cell survival. This study provides new insights into the molecular mechanism of autophagy involved in AGE-induced apoptosis in mesangial cells.