Retracted: Bilobalide alleviates tumor necrosis factor‐alpha‐induced pancreatic beta‐cell MIN6 apoptosis and dysfunction through upregulation of miR‐153

Type 1 diabetes mellitus (T1DM) is a systemic disease and one classical type of total DM. Bilobalide (BB) is constituted of EGb 761. Our purpose was identifying the role of BB in TIDM in the current study. MIN6 cells were treated by TNF‐α; then, viability, apoptosis, and insulin secretion were assessed by performing Cell Counting Kit‐8 assay, flow cytometry, glucose‐stimulated insulin secretion assay, and western blot. The effects of BB were assessed to identify its function. Further, the above mentioned parameters were reassessed when silencing miR‐153. TNF‐α declined viability and insulin secretion as well as raised apoptosis and inducible nitric oxide synthase (iNOS) expression in MIN6 cells. BB alleviated the apoptosis and dysfunction induced by TNF‐α. MiR‐153 expression was elevated by BB when induced by TNF‐α. Increase of viability and insulin secretion as well as decline of apoptosis and iNOS induced by BB treatment was alleviated by silencing miR‐153. The rates of p/t‐p70S6K, p/t‐mammalian target of rapamycin (mTOR) and p/t‐adenosine monophosphate‐activated protein kinase (AMPK) were raised by BB and suppressed by silencing miR‐153 under TNF‐α induced condition. BB raised viability and insulin secretion, declined apoptosis and iNOS expression by up‐regulating miR‐153. Furthermore, BB activated AMPK/mTOR pathway by up‐regulating miR‐153.     

1,7‐Bis(4‐hydroxyphenyl)‐4‐hepten‐3‐one from Betula platyphylla induces apoptosis by suppressing autophagy flux and activating the p38 pathway in lung cancer cells

Betula platyphylla (BP) is frequently administered in the treatment of various human diseases, including cancers. This study was undertaken to investigate the pharmacological function of the active components in BP and the underlying mechanism of its chemotherapeutic effects in human lung cancer cells. We observed that BP extracts and 1,7‐bis(4‐hydroxyphenyl)‐4‐hepten‐3‐one (BE1), one of the components of BP, effectively decreased the cell viability of several lung cancer cell lines. BE1‐treated cells exhibited apoptosis induction and cell cycle arrest at the G2/M phase. Further examination demonstrated that BE1 treatment resulted in suppression of autophagy, as evidenced by increased protein expression levels of both LC3 II and p62/SQSTM1. Interestingly, the pharmacological induction of autophagy with rapamycin remarkably reduced the BE1‐induced apoptosis, indicating that apoptosis induced by BE1 was associated with autophagy inhibition. Our data also demonstrated that BE1 exposure activated the p38 pathway resulting in regulation of the pro‐apoptotic activity. Taken together, we believe that BE1 is a potential anticancer agent for human lung cancer, which exerts its effect by enhancing apoptosis via regulating autophagy and the p38 pathway.     

Retracted: Ganoderic Acid A exerts the cytoprotection against hypoxia‐triggered impairment in PC12 cells via elevating microRNA‐153

Ganoderic Acid A (GAA) is often applied for healing cardiovascular and cerebrovascular ailments, but the influences in cerebral ischemia injury are still hazy. The research delved into the functions of GAA in hypoxia‐triggered impairment in PC12 cells. PC12 cells received hypoxia management for 12 hr, and subsequently, cell viability, migration, apoptosis, and correlative protein levels were assessed. After preprocessing with GAA, above cell behaviors were monitored again. The vector of microRNA (miR)‐153 inhibitor was utilized for PC12 cell transfection to further explore the functions of miR‐153 in hypoxia‐impaired cells. Pathways of phosphatidylinositol 3‐kinase (PI3K)/protein kinase B (AKT) and mammalian target of rapamycin (mTOR) were investigated via executing western blot for uncovering the latent mechanism. Results revealed that hypoxia disposition triggered PC12 cells impairment via restraining cell viability and migration and accelerating apoptosis. However, GAA visibly mollified hypoxia‐provoked impairment in PC12 cells. Interestingly, the enhancement of miR‐153 triggered by GAA was observed in hypoxia‐impaired PC12 cells. After miR‐153 inhibitor transfection, the protective functions of GAA in hypoxia‐impaired PC12 cells were dramatically inversed. Furthermore, GAA caused PI3K/AKT and mTOR activations via enhancement of miR‐153 in hypoxia‐impaired PC12 cells. The findings evinced that GAA exhibited the protective functions in PC12 cells against hypoxia‐evoked impairment through activating PI3K/AKT and mTOR via elevating miR‐153.     

Curcumin inhibits cell viability,migration, and invasion of thymic carcinoma cells via downregulation of microRNA‐27a

Curcumin (CUR) is a kind of polyphenolic compound and widely used in the treatment of diseases. However, the involvement of CUR in thymic carcinoma remains unknown. The object of our research is to clarify the role of CUR and related regulatory mechanism in thymic carcinoma cells. After treatment with CUR for 24 hr, cell viability, apoptosis, migration, and invasion of TC1889 cells were measured. Real‐time polymerase chain reaction was executed to examine the expression of microRNA‐27a (miR‐27a) in thymic carcinoma tissues and TC1889 cells. After miR‐27a mimic transfection, whether miR‐27a is involved in CUR‐modulated cell behaviors was measured. Finally, western blot was utilized to detect mTOR and Notch 1 pathways‐linked proteins. CUR restrained cell viability and increased cell apoptosis of TC1889 cells. In addition, cell migration and invasion were restrained by CUR. Meanwhile, miR‐27a expression was positively regulated in thymic carcinoma tissues and downregulated by CUR in TC1889 cells. Overexpressed miR‐27a reversed the CUR‐induced reduction of growth, migration, and invasion in TC1889 cells. Furthermore, CUR blocked mTOR and Notch 1 pathways via downregulating miR‐27a. We demonstrated that CUR blocked mTOR and Notch 1 pathways via downregulating miR‐27a, thereby suppressing cell growth, migration, and invasion of thymic carcinoma cells.     

Retracted: Ganoderic acid A alleviates hypoxia‐induced apoptosis,autophagy, and inflammation in rat neural stem cells through the PI3K/AKT/mTOR pathways

Effects of ganoderic acid A (GAA), a lanostane triterpene, on hypoxia‐ischemia encephalopathy (HIE) remain unclear. We aimed to figure out the specific role of GAA in hypoxia‐treated neural stem cells (NSCs) as well as the regulatory mechanisms. Primary rat NSCs were incubated under hypoxia to simulate HIE. Viability and apoptosis of hypoxia‐injured NSCs were measured by cell counting kit‐8 and flow cytometry assays, respectively. Proteins related to apoptosis, autophagy, and the PI3K/AKT/mTOR pathways were evaluated by Western blot analysis. LY294002 and rapamycin were added to inhibit the PI3K/AKT pathway and mTOR pathway, respectively. Enzyme‐linked immunosorbent assay was carried out to test the release of proinflammatory cytokines. We found that hypoxia‐induced decrease of cell viability, increases of apoptotic cells and autophagy, and the release of IL‐6, IL‐1β, and TNF‐α were all attenuated by GAA stimulation. Activation of caspases induced by hypoxia was alleviated by GAA. Furthermore, we found that inhibition of the PI3K/AKT pathway eliminated the effects of GAA on apoptosis and proinflammatory cytokines release in hypoxia‐injured NSCs. Meanwhile, inhibition of the mTOR pathway abrogated the effects of GAA on cell autophagy in hypoxia‐injured NSCs. In conclusion, GAA alleviated hypoxia‐induced injury in NSCs might be through activating the PI3K/AKT and mTOR pathways.     

Matrine triggers colon cancer cell apoptosis and G0/G1 cell cycle arrest via mediation of microRNA‐22

Matrine (MAT) is an alkaloid in the dried roots of Sophora flavescens. The antitumor activity has been testified in colon cancer. Howbeit, the latent mechanism is still indistinct. The research probed the antitumor mechanism of MAT in colon cancer cells. MAT (0.25, 0.5, 0.75, 1, and 1.25 mM) was utilized to stimulate SW480 and SW620 cells for 24, 48, and 72 hr. Cell viability, apoptosis, cell cycle, and the correlative proteins were assessed via Cell Counting Kit‐8, flow cytometry, and Western blot. microRNA‐22 (miR‐22) in MAT‐treated or miR‐22‐silenced cells was estimated via real‐time quantitative polymerase chain reaction. The functions of miR‐22 inhibition were reassessed. Western blot was conducted for quantifying β‐catenin, MEK, and ERK. Luciferase reporter assay was done for confirming the targeting relationship between miR‐22 and ERBB3 or MECOM. MAT prohibited cell viability, accelerated apoptosis, and triggered cells cycle stagnation at G0/G1 phase. Additionally, miR‐22 was elevated by MAT; meanwhile, the influences of MAT were all inverted by miR‐22 inhibitor. MAT enhanced the expression of miR‐22, thereby obstructing Wnt/β‐catenin and MEK/ERK pathways. miR‐22 had a potential to target mRNA 3'UTR of ERBB3 and MECOM. These discoveries manifested that MAT could evoke colon cancer cell apoptosis and G0/G1 cell cycle arrest via elevating miR‐22.     

Anti‐Proliferative Effects of Polyphenols from Pomegranate Rind (Punica granatum L.) on EJ Bladder Cancer Cells Via Regulation of p53/miR‐34a Axis

miRNAs and their validated miRNA targets appear as novel effectors in biological activities of plant polyphenols; however, limited information is available on miR‐34a mediated cytotoxicity of pomegranate rind polyphenols in cancer cell lines. For this purpose, cell viability assay, Realtime quantitative PCR for mRNA quantification, western blot for essential protein expression, p53 silencing by shRNA and miR‐34a knockdown were performed in the present study. EJ cell treatment with 100 µg (GAE)/mL PRE for 48 h evoked poor cell viability and caspase‐dependent pro‐apoptosis appearance. PRE also elevated p53 protein and triggered miR‐34a expression. The c‐Myc and CD44 were confirmed as direct targets of miR‐34a in EJ cell apoptosis induced by PRE. Our results provide sufficient evidence that polyphenols in PRE can be potential molecular clusters to suppress bladder cancer cell EJ proliferation via p53/miR‐34a axis. Copyright © 2015 John Wiley & Sons, Ltd.     

Curcumin Modulates miR‐19/PTEN/AKT/p53 Axis to Suppress Bisphenol A‐induced MCF‐7 Breast Cancer Cell Proliferation

Breast cancer is the most common cancer in women. Bisphenol A (BPA), as a known endocrine disrupter, is closely related to the development of breast cancer. Curcumin has been clinically used in chemopreventation and treatment of cancer; however, it remains unknown whether microRNAs are involved in curcumin‐mediated protection from BPA‐associated promotive effects on breast cancer. In the present study, we showed that BPA exhibited estrogenic activity by increasing the proliferation of estrogen‐receptor‐positive MCF‐7 human breast cancer cells and triggering transition of the cells from G1 to S phase. Curcumin inhibited the proliferative effects of BPA on MCF‐7 cells. Meanwhile, BPA‐induced upregulation of oncogenic miR‐19a and miR‐19b, and the dysregulated expression of miR‐19‐related downstream proteins, including PTEN, p‐AKT, p‐MDM2, p53, and proliferating cell nuclear antigen, were reversed by curcumin. Furthermore, the important role of miR‐19 in BPA‐mediated MCF‐7 cell proliferation was also illustrated. These results suggest for the first time that curcumin modulates miR‐19/PTEN/AKT/p53 axis to exhibit its protective effects against BPA‐associated breast cancer promotion. Findings from this study could provide new insights into the molecular mechanisms by which BPA exerts its breast‐cancer‐promoting effect as well as its target intervention. Copyright © 2014 John Wiley & Sons, Ltd.     

6-Methoxydihydrosanguinarine induces apoptosis and autophagy in breast cancer MCF-7 cells by accumulating ROS to suppress the PI3K/AKT/mTOR signaling pathway

6-Methoxydihydrosanguinarine (6-MDS) is a natural benzophenanthridine alkaloid extracted from Hylomecon japonica (Thunb.) Prantl. It is the first time to explore the effect and mechanism of 6-MDS in breast cancer. Network pharmacology, molecular docking, and molecular dynamics simulation technology were adopted to identify the potential targets and pathways of 6-MDS in breast cancer. Besides, cell proliferation, apoptosis, and western blotting assays were conducted to investigate the effect of 6-MDS on MCF-7 cells. Network pharmacology, molecular docking, and molecular dynamics simulation results confirmed the effect of 6-MDS on resisting breast cancer via the PI3K/AKT/mTOR signaling pathway. In addition, the functional experiments results demonstrated that 6-MDS inhibited proliferation and induced apoptosis and autophagy. The autophagy inhibitor chloroquine and the silence of Atg5 augmented the effect of 6-MDS on promoting apoptosis. Furthermore, 6-MDS suppressed the PI3K/AKT/mTOR signaling pathway, and the PI3K inhibitor LY294002 enhanced these changes and promoted the 6-MDS pro-apoptotic and autophagy effects. 6-MDS triggered the generation of reactive oxygen species. The pretreatment with antioxidant N-acetyl-L-cysteine reversed the changes induced by 6-MDS, including increases in apoptosis and autophagy and inhibition of the PI3K/AKT/mTOR pathway. In conclusion, 6-MDS induces the apoptosis and autophagy of MCF-7 cells by ROS accumulation to suppress the PI3K/AKT/mTOR signaling pathway.     

Retracted: Lipopolysaccharides‐mediated injury to chondrogenic ATDC5 cells can be relieved by Sinomenine via downregulating microRNA‐192

Sinomenine (SIN) is an isoquinoline derived from Caulis Sinomenii that has been used to treat rheumatoid arthritis and osteoarthritis for several decades in China. This study aims to reveal the effects of SIN on mouse chondrogenic ATDC5 cells growth and inflammation. SIN was used to treat ATDC5 cells injured by lipopolysaccharides (LPS). The following parameters were determined for evaluating the treatment effects of SIN: cell viability, apoptosis, reactive oxygen species generation, and pro‐inflammatory cytokines release. Besides, the expression of LPS‐sensitive miRNA (miR‐192) and the activation of NF‐κB and MAPK signaling were studied to explain SIN's function. SIN with concentration of 30 μM significantly attenuated LPS‐induced cell damage via increasing cell viability, inhibiting apoptosis and reactive oxygen species generation, and declining IL‐6 and TNF‐α release. miR‐192 was downregulated by SIN treatment. Restoration of miR‐192 expression by miRNA transfection could significantly impede SIN's protective action. Besides, the inhibitory effects of SIN on the activation of NF‐κB and MAPK signaling were attenuated by miR‐192 overexpression. Furthermore, GDF11 was found to be a target gene of miR‐192. LPS‐mediated injury to chondrogenic ATDC5 cells can be relieved by SIN via downregulating miR‐192 and subsequently repressing the activation of NF‐κB and MAPK signaling.     

Retracted: Baicalin relieves TNF‐α‐evoked injury in human aortic endothelial cells by up‐regulation of miR‐145

Hypertension is recognized to be associated with low‐grade inflammation. Baicalin (BAI) is reported to possess various pharmacological including anti‐inflammatory activities. This research explored the molecular mechanism by which BAI functions in human aortic endothelial cells (HAECs). HAECs were pretreated with BAI. Cell viability, apoptosis, and expressions of crucial proteins were respectively evaluated using cell counting kit‐8 assay, flow cytometry, and western blot. Productions of cytokines were respectively assessed employing quantitative real‐time polymerase chain reaction and enzyme‐linked immunosorbent assay. Cell transfection was utilized to alter miR‐145 expression. The expressions of proteins participated in JNK and p38MAPK pathways were analyzed utilizing western blot. TNF‐α inducement successfully evoked inflammatory injury in HAECs, exhibiting as prominently suppressed viability, while facilitated apoptosis and productions of cytokines. However, BAI pretreatment significantly ameliorated TNF‐α‐triggered inflammatory injuries. Besides, miR‐145 expression was markedly inhibited by TNF‐α inducement, while notably elevated by BAI pretreatment. Although miR‐145 overexpression had no significant influence on apoptosis, miR‐145 silence observably reversed BAI pretreatment‐evoked protective influences on TNF‐α‐induced HAECs, as well as the inhibited impacts on the levels of key proteins involved in JNK and p38MAPK pathways. This investigation illustrated that BAI relieved TNF‐α‐triggered injuries through upregulating miR‐145 via suppressing JNK and p38MAPK pathways.     

Turmeric Toxicity in A431 Epidermoid Cancer Cells Associates with Autophagy Degradation of Anti‐apoptotic and Anti‐autophagic p53 Mutant

The keratinocyte‐derived A431 Squamous Cell Carcinoma cells express the p53R273H mutant, which has been reported to inhibit apoptosis and autophagy. Here, we show that the crude extract of turmeric (Curcuma longa), similarly to its bioactive component Curcumin, could induce both apoptosis and autophagy in A431 cells, and these effects were concomitant with degradation of p53. Turmeric and curcumin also stimulated the activity of mTOR, which notoriously promotes cell growth and acts negatively on basal autophagy. Rapamycin‐mediated inhibition of mTOR synergized with turmeric and curcumin in causing p53 degradation, increased the production of autophagosomes and exacerbated cell toxicity leading to cell necrosis. Small‐interference mediated silencing of the autophagy proteins BECLIN 1 or ATG7 abrogated the induction of autophagy and largely rescued p53 stability in Turmeric‐treated or Curcumin‐treated cells, indicating that macroautophagy was mainly responsible for mutant p53 degradation. These data uncover a novel mechanism of turmeric and curcumin toxicity in chemoresistant cancer cells bearing mutant p53. Copyright © 2014 John Wiley & Sons, Ltd.     

Tanshinone IIA Induces Autophagic Cell Death via Activation of AMPK and ERK and Inhibition of mTOR and p70 S6K in KBM‐5 Leukemia Cells

Although tanshinone IIA (Tan IIA) from Salviae miltiorrhizae was known to induce apoptosis in various cancers, its underlying mechanism of autophagic cell death was not reported yet. Thus, in the present study, the molecular mechanism of autophagic cell death by Tan IIA was investigated in KBM‐5 leukemia cells. Tan IIA significantly increased the expression of microtubule‐associated protein light chain 3 (LC3) II as a hallmark of autophagy in western blotting and immunofluorescence staining. Tan IIA augmented the phosphorylation of adenosine monophosphate‐activated protein kinase (AMPK) and attenuated the phosphorylation of mammalian target of rapamycin (mTOR) and p70 S6K in a dose‐dependent manner. Conversely, autophagy inhibitor 3‐methyladenine partly reversed the cytotoxicity and the phosphorylation of AMPK, mTOR and p70 S6K induced by Tan IIA in KBM‐5 leukemia cells. In addition, Tan IIA dramatically activated the extracellular signal regulated kinase (ERK) signaling pathway including Raf, ERK and p90 RSK in a dose‐dependent and time‐dependent manner. Consistently, ERK inhibitor PD184352 suppressed LC3‐II activation induced by Tan IIA, whereas PD184352 and PD98059 did not affect poly (ADP‐ribose) polymerase cleavage and sub‐G1 accumulation induced by Tan IIA in KBM‐5 leukemia cells. Furthermore, Tan IIA could induce autophagy via LC3‐II activation in various cancer cells such as prostate (PC‐3), multiple myeloma (U266), lung (NCI‐H460), and breast (MDA‐MB‐231) cells. Overall, these findings suggest that Tan IIA induces autophagic cell death via activation of AMPK and ERK and inhibition of mTOR and p70 S6K in KBM‐5 cells as a potent natural compound for leukemia treatment. Copyright © 2013 John Wiley & Sons, Ltd.     

Paris saponin VII induces cell cycle arrest and apoptosis by regulating Akt/MAPK pathway and inhibition of P‐glycoprotein in K562/ADR cells

Paris saponinVII (PSVII) is a steroidal saponin isolated from the roots and rhizomes of Trillium tschonoskii Maxim. We found that PSVII could inhibit the growth of adriamycin‐resistant human leukemia cells (K562/ADR) in a dose‐dependent manner. Furthermore, the molecular mechanism underlying the cytotoxicity and downregulation of P‐glycoprotein (P‐gp) expression by PSVII was clarified. PSVII significantly suppressed cell proliferation by cell cycle arrest in the G0/G1 phase, which was associated with an obvious decrease in cyclin B1/D1 and CDK2/4/6 protein expression. Moreover, PSVII could attenuate mitochondrial membrane potential, increase the expression of apoptosis‐related proteins, such as Bax and cytochrome c, and decrease the protein expression levels of Bcl‐2, caspase‐9, caspase‐3, PARP‐1, and p‐Akt. We also found that JNK, ERK1/2, and p38 were regulated by PSVII in K562/ADR cells. And further studies indicated that the decrease in the reactive oxygen species level inhibited intrinsic P‐gp expression. Therefore, PSVII‐induced apoptosis in K562/ADR cells was associated with Akt/MAPK and the inhibition of P‐gp. In addition, PSVII induced a robust autophagy in K562/ADR cells as demonstrated by the degradation of LC3‐I. These results provide a biochemical basis for possible clinical applications of PSVII in the treatment of leukemia.     

Retracted: Baicalin relieves lipopolysaccharide‐evoked inflammatory injury through regulation of miR‐21 in H9c2 cells

Myocarditis is a common heart disease which lacks effective treatment till now. Baicalin possesses plenty of activities, including anti‐inflammation. In this investigation, we attempted to investigate the influences of Baicalin on Lipopolysaccharide (LPS)‐evoked H9c2 cells.Cells viability, apoptosis, and expressions of apoptosis‐associated proteins were, respectively, measured utilizing CCK‐8 assay, flow cytometry and western blot. The levels of IL‐6 and TNF‐α were detected through enzyme‐linked immunosorbent assay, western blot and qRT‐PCR. miR‐21 expression was detected through qRT‐PCR and was silenced using cell transfection. The expressions of NF‐κB and PDCD4/JNK pathways related proteins were measured through western blot. We found that LPS stimulation induced cell apoptosis and upregulation of IL‐6 and TNF‐α. Baicalin treatment effectively suppressed LPS‐induced inflammation and apoptosis. The NF‐κB and PDCD4/JNK pathways were blocked by Baicalin. Additionally, the enhanced expression of miR‐21 triggered by LPS was further elevated by Baicalin. Further study revealed that the inhibiting effects of Baicalin on LPS‐evoked injury were largely attenuated by knockdown of miR‐21. Moreover, the associated NF‐κB and JNK pathways, which were suppressed by Baicalin treatment, were then activated by knockdown of miR‐21. Our present study revealed that Baicalin alleviated LPS‐evoked inflammatory injury via suppressing the NF‐κB and PDCD4/JNK pathways through regulating miR‐21 expression.     

Palmitoylethanolamide Exerts Antiproliferative Effect and Downregulates VEGF Signaling in Caco‐2 Human Colon Carcinoma Cell Line Through a Selective PPAR‐α‐Dependent Inhibition of Akt/mTOR Pathway

Palmitoylethanolamide (PEA) is a nutraceutical compound that has been demonstrated to improve intestinal inflammation. We aimed at evaluating its antiproliferative and antiangiogenic effects in human colon adenocarcinoma Caco‐2 cell line. Caco‐2 cells were treated with increasing concentrations of PEA (0.001, 0.01 and 0.1 μM) in the presence of peroxisome proliferator‐activated receptor‐a (PPAR‐α) or PPAR‐γ antagonists. Cell proliferation was evaluated by performing a MTT assay. Vascular endothelial growth factor (VEGF) release was estimated by ELISA, while the expression of VEGF receptor and the activation of the Akt/mammalian target of rapamycin (mTOR) pathway were evaluated by western blot analysis. PEA caused a significant and concentration‐dependent decrease of Caco‐2 cell proliferation at 48 h. PEA administration significantly reduced in a concentration‐dependent manner VEGF secretion and VEGF receptor expression. Inhibition of Akt phosphorylation and a downstream decrease of phospho‐mTOR and of p‐p70S6K were observed as compared with untreated cells. PPAR‐α, but not PPAR‐γ antagonist, reverted all effects of PEA. PEA is able to decrease cell proliferation and angiogenesis. The antiangiogenic effect of PEA depends on the specific inhibition of the AkT/mTOR axis, through the activation of PPAR‐α pathway. If supported by in vivo models, our data pave the way to PEA co‐administration to the current chemotherapeutic regimens for colon carcinoma. Copyright © 2016 John Wiley & Sons, Ltd.     

Protective Effects of Gastrodin Against Autophagy‐Mediated Astrocyte Death

Gastrodin is an active ingredient derived from the rhizome of Gastrodia elata. This compound is usually used to treat convulsive illness, dizziness, vertigo, and headache. This study aimed to investigate the effect of gastrodin on the autophagy of glial cells exposed to lipopolysaccharides (LPS, 1 µg/mL). Autophagy is a form of programmed cell death, although it also promotes cell survival. In cultured astrocytes, LPS exposure induced excessive autophagy and apoptosis, which were significantly prevented by the pretreatment cells with gastrodin (10 μM). The protective effects of gastrodin via autophagy inhibition were verified by the decreased levels of LC3‐II, P62, and Beclin‐1, which are classical markers for autophagy. Furthermore, gastrodin protected astrocytes from apoptosis through Bcl‐2 and Bax signaling pathway. The treatment of astrocytes with rapamycin (500 nM), wortmannin (100 nM), and LY294002 (10 μM), which are inhibitors of mTOR and PI3K, respectively, eliminated the known effects of gastrodin on the inhibited Beclin‐1 expression. Furthermore, gastrodin blocked the down‐regulation of glutamine synthetase induced by LPS exposure in astrocytes. Our results suggest that gastrodin can be used as a preventive agent for the excessive autophagy induced by LPS. Copyright © 2015 John Wiley & Sons, Ltd.     

Celastrol inhibits growth and metastasis of human gastric cancer cell MKN45 by down‐regulating microRNA‐21

Celastrol could inhibit cancer cell growth in vitro. However, effect(s) of celastrol on gastric cancer is not well studied. Therefore, we investigated the effects of celastrol on human gastric cancer cell line MKN45 and the underlying mechanisms. We found that celastrol inhibited cell proliferation, migration, and invasion and induced cell apoptosis and G2/M cell cycle arrest (p < .05, p < .01, or p < .001). Under celastrol treatment, overexpression of microRNA‐21 (miR‐21) increased cell viability, migration, and invasion and inhibited cell apoptosis compared with negative control (p < .05, p < .01, or p < .001). In addition, the phosphorylation of PTEN was significantly up‐regulated, whereas PI3K, AKT, p65, and IκBα phosphorylation was statistically decreased by celastrol (p < .05 or p < .01) and then further reversed by miR‐21 overexpression (p < .05 or p < .01). On the other side, miR‐21 silence showed contrary results (p < .05) as relative to miR‐21 overexpression. In conclusion, celastrol inhibits proliferation, migration, and invasion and inactivates PTEN/PI3K/AKT and nuclear factor κB signaling pathways in MKN45 cells by down‐regulating miR‐21.