Retraction Statement

RETRACTED Tanshinone IIA Affects Autophagy and Apoptosis of Glioma Cells by Inhibiting Phosphatidylinositol 3-Kinase/Akt/Mammalian Target of Rapamycin Signaling Pathway

One of the most important abnormalities of the tubular epithelial cells lining the cysts as well as noncystic tubular epithelium is a disturbance in the balance between tubular cell proliferation and apoptosis. Activation of the mammalian target of rapamycin signaling pathway results in increased cell proliferation. Recent studies suggested abnormalities of the mammalian target of rapamycin signaling pathway in polycystic kidney disease. Mammalian target of rapamycin inhibition with sirolimus or everolimus results in attenuation of cyst formation in rat and mouse models of polycystic kidney disease. Apoptosis is a pathologic feature of most models of polycystic kidney disease, including human polycystic kidneys. Caspases, the major mediators of apoptosis, are increased in polycystic kidney disease kidneys. Both in vitro and in vivo studies suggest that caspase or apoptosis inhibition attenuates cyst formation. This review focuses on mammalian target of rapamycin and apoptosis signaling pathways in polycystic kidney disease and the role of mammalian target of rapamycin inhibitors and apoptosis inhibitors as potential therapies to reduce cyst formation.

Objective To investigate the effects of NADPH oxidase (NOX) on the survival,proliferation and apoptosis of U251 glioma cells. Methods RT-PCR was employed to examine the expressions of NOX genes in the U251 glioma cells. Five, 15 and 25 μmol/L diphenyleneiodonium (DPI,the NOX inhibitor) and 10 mmol/L antioxidant Tiron were added into the cells, respectively, and 24 h after that, the proliferation of U251 glioma cells was tested by alamarBlue assay, and the production of intraceilular reactive oxygen species (ROS) and the apoptosis of U251 glioma cells were examined by flow cytometry. These results were compared with those in the normal control group. Results High mRNA expression level of NOX4 gene was found in the U251 glioma cells. DPI at each concentration can inhibit the growth of U251 glinma cells and induce the apoptosis of U251 glioma cells. Compared with the normal control group, the treatment groups showed significantly decreased ROS in the U251 glioma cells (P<0.05). Conclusion NOX4 gene may be a major source that generates the intracellular ROS in the glioma cells. NOX4 gene regulates the proliferation, survival and apoptosis of glioma cells through increasing the level of ROS and then acting on its downstream regulatory molecules. Key words: NADPH oxidase; Reactive oxygen species; Diphenyleneiodonium; Glioma; Apoptosis

Objective To investigate the effects of norcantharidin (NCTD) on the proliferation and apoptosis on glioma cells. Methods Glioma U87 cells were treated with various concentrations of NCTD (25, 50, 100, 200 μmol/L) for 24, 48 h. The effects of NCTD on the proliferation and apoptosis of glioma cells were measured by methyl thiazol tetrazolium (MTT) assay and flow cytometry. The Mitogen-activated protein kinase/extracellular regulated protein kinase (MAPK/ERK) signaling pathway changes were detected by Western blotting. Results The results showed that NCTD effectively inhibited cell growth and induced apoptosis in U87 cells in a time- and dose-dependent manner. After incubation with NCTD for 24 h and 48 h, the average half maximal inhibitory concentration (IC50) was 147.7 μmol/L and 62.5 μmol/L, respectively. It could significantly inhibit proliferation at 24 h and 48 h (F=30.234, 42.106, P=0.000). As compared with the control group [(1.2±0.9)%], the cell apoptosis rate induced by 30, 50 μmol/L of NCTD for 10 h was (6.8±1.2)% and (17.2±2.0)%, respectively, which indicated that NCTD could induce apoptosis of cells in a dose-dependent manner (F=405.761, P=0.000). Western blotting results revealed that the phospho-MEK and phospho-ERK were down-regulated significantly in NCTD group as compared with control group (P=0.007). Conclusion Our findings demonstrated that NCTD inhibited proliferation and induced apoptosis of U87 glioma cells through MAPK/ERK signaling pathway. Key words: Glioma; Norcantharidin; Mitogen-activated protein kinase/extracellular regulated protein kinase signaling pathway; Apoptosis

DNA methylation modulates allograft survival and acute rejection after renal transplantation by regulating the mTOR pathway

Objective To investigate the effects of quercetin on cell viability,apoptosis,autophagy,and phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)/mammalian target of rapamycin(mTOR)signaling pathway in human prostate cell carcinoma PC-3 cells.Methods PC-3 cells were cultured in vitro,and cell viability was detected by CCK-8.Apoptosis was detected by TUNEL staining.Autophagy vesicle was observed by acridine orange staining.Autophagosomes was observed by GFP-LC3 plasmid transfection analysis.Expressions of autophagy-related protein microtubule associated protein 1 light chain 3 fusion protein(LC3)and Beclin-1 and PI3K/Akt/mTOR signaling pathway protein were detected by Western blot analysis.Results Quercetin inhibited cell viability in a dose-time dependent manner and induced apoptosis.Quercetin increased the number of autophagy vesicles and autophagosomes in PC-3 cells.Quercetin increased the expressions of LC3-Ⅱ/LC3-Ⅰ and Beclin-1 in PC-3 cells and decreased the expression of phosphorylated-PI3K,phosphorylated-Akt and phosphorylated-mTOR.Conclusion Quercetin may induce autophagy by inactivating PI3K/Akt/mTOR signaling pathway in PC-3 cells.

Objective To investigate the effect of As4S4 inhibit the growth of breast cancer cell by regulating phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signal pathway. Methods Methyl thiazol tetrazolium (MTT) assay was used to detect breast cancer cell MCF-7 proliferation after 0, 20, 40, 60, 80 μmol/L As4S4 treatment for 24, 48, 72 h, and 10 μmol/L LY294002 treatment 48 h. Wound healing and transwell were used to detect the distance of MCF-7 cell migration and invasion after As4S4 dealing with 48 h. Flow cytometry was used to detect MCF-7 cell apoptosis after and 10 μmol/L LY294002 treatment 48 h. Western blotting was used to detect PI3K, p-Akt, mTOR expression levels in MCF-7 cell after As4S4 and 10 μmol/L LY294002 dealing with 48 h. Results Compared with 0 μmol/L treatment, 20 μmol/L As4S4 had no significant inhibition of cell proliferation at 24 h (P=0.065), it had a significant inhibition of cell proliferation at 48 h and 72 h (P=0.033) with the inhibition ratio of 11.1% and14.3%, respectively.40, 60, 80 μmol/L As4S4 treatment had the most obvious inhibitory effect at 72 h (P=0.002) the inhibition ratio of 47.9%, 58.8%, 67.1%, respectively. After60 As4S4 treatment for 48 h, the migration rate and invasion ability of MCF-7 cell were lower than the control group (with decrease of 42.4%), the difference was significant (P=0.005), the apptosis rate was significant increased to (19.56±1.12)% (P=0.009), the expression of PI3K in MCF-7 cell had no significantly change and p-Akt, mTOR were significantly decreased than control group (P=0.008) with the decrease of 64.3% and 58.7%, respectively. The results of proliferation and apoptosis was consistent with the LY294002 treatment. Conclusion As4S4 may inhibit breast cancer MCF-7 cell proliferation and metastasis and promote apoptosis by inhibiting PI3K/Akt/mTOR signaling pathway. Key words: As4S4; Breast cancer; Proliferation; Transfer; Apoptosis

Gambogic acid (GA) is a natural compound with a polyprenylated xanthone structure that has antiinflammatory, antioxidant, and neuroprotective properties and acts as a chemopreventive agent. GA exhibits anti-tumor, antimicrobial, and anti-proliferative effects on cancer cells. In the current study, the effect of GA on phosphoinositide kinase-3 (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway was examined in human U251 glioma cells. Cell viability and apoptosis were evaluated by MTT and Annexin V/PI Double Staining. The expressions of P38, AKT, and mTOR were evaluated by western blot and qRT-PCR, respectively. MagBeads Total RNA Extraction Kit was used to isolate cell tissue RNA. GA decreased the phosphorylation of P38, AKT, and mTOR. Inhibitors of PI3K (LY294002) enhanced the phosphorylation of P38, AKT, and mTOR. GA reduced the phosphorylation of ribosomal protein precursors (Pre) and upstream binding factor (UBF), and insulin-like growth factor I (IGF-1) further enhanced the cell proliferation and expression of Pre and UBF. These results suggested that downregulation of PI3K/AKT/mTOR signaling pathway may be an important mediator in GA-affected ribosomal occurrence in glioma cells.

The mechanisms of the antitumor effects of tamoxifen upon gliomas are still unclear. In this study, we investigated the role of c-Jun N-terminal kinase-1 (JNK1) and caspase 3 in the tamoxifen-induced apoptosis of rat glioma cells. Glioma cells were treated with tamoxifen, followed by a cytotoxicity assay to study its effects on the cells, and then a flow-activated cell sorter (FACS) analysis was performed to analyze the cellular apoptosis of the glioma cells. The expression of JNK1 and phospho-specific JNK1 in glioma cells treated with tamoxifen was investigated by Western blot analysis. The activity of caspase 3 in glioma cells was analyzed by caspase activity assay. Tamoxifen was demonstrated to exert cytotoxic effects upon and induced apoptosis of the glioma cells in a concentration- and time-dependent manner (P<0.05). Western blot analysis demonstrated that tamoxifen increased the expression of phospho-specific JNK1 in glioma cells, and an increasing concentration of tamoxifen induced an increasing expression of phospho-specific JNK1. Four-hour 50-microM tamoxifen treatment increased the expression of phospho-specific JNK1 to 3.2 times that of the control level in glioma cells. Tamoxifen also increased the activity of caspase 3 in glioma cells. Pretreatment of glioma cells with the antisense oligonucleotide (OGN) of JNK1 immediately prior to tamoxifen treatment suppressed the expression of phospho-specific JNK1 and the activity of caspase 3. The apoptosis fraction of glioma cells induced by 4-h treatment with 50 microM tamoxifen was decreased from 51% to 28% by pretreatment with the antisense OGN of JNK1 (P<0.003), and to 20% by pretreatment with caspase 3 inhibitor (DEVD-CHO) (P<0.0008). The results suggest that the tamoxifen-induced apoptosis of rat glioma cells is related to the activation of the JNK1/caspase 3 signaling pathway; however, the confirmation of the occurrence of such activation in vivo needs further investigation.

BackgroundThe mammalian target of rapamycin (mTOR) signaling pathway is vital for the regulation of cell metabolism, growth and proliferation in the kidney. This study aims to show current research focuses and predict future trends about mTOR pathway in kidney disease by the methods of scientometric analysis.MethodsWe referred to publications from the Web of ScienceTM Core Collection (WoSCC) Database. Carrot2, VOSviewer and CiteSpace programs were applied to evaluate the distribution and contribution of authors, institutes and countries/regions of extensive bibliographic metadata, show current research focuses and predict future trends in kidney disease’s area.ResultsUntil July 10, 2020, there are 2,585 manuscripts about mTOR signaling pathway in kidney disease in total and every manuscript is cited 27.39 times on average. The big name of course is the United States. Research hot spots include “diabetic nephropathy”, “kidney transplantation”, “autosomal dominant polycystic kidney disease”, “tuberous sclerosis complex”, “renal cell carcinoma” and “autophagy”. Seven key clusters are detected, including “kidney transplantation”, “autosomal dominant polycystic kidney disease”, “renal transplantation”, “renal cell carcinoma”, “hamartin”, “autophagy” and “tuberous sclerosis complex”.ConclusionsDiabetic nephropathy, kidney transplantation, autosomal dominant polycystic kidney disease, tuberous sclerosis complex, renal cell carcinoma and autophagy are future research hot spots by utilizing scientometric analysis. In the future, it is necessary to research these fields.

Objective:One of the main complications of sepsis that is linked to poor clinical outcomes and high mortality is sepsis-induced myocardial dysfunction (SIMD). Fatty acid-binding protein 4 (FABP4) is a protein that is expressed in macrophages and adipose tissue and is involved in inflammation and apoptosis in various pathological processes. The purpose of this study was to investigate the role of FABP4 in SIMD.Material and Methods:The H9c2 cell model of myocardial dysfunction induced by septicemia was established by lipopolysaccharide (LPS). Measurements of cell viability, apoptosis, reactive oxygen species levels, mitochondrial activity, and proinflammatory factor expression were used to assess FABP4’s involvement in SIMD. In addition, the expression level of key proteins in the mammalian target of rapamycin (mTOR) signaling pathway was analyzed using Western blot. Finally, the combination of AZD-8055 further demonstrated the possibility of mTOR as a therapeutic target for SIMD.Results:Silencing FABP4 expression drastically increased H9c2 cell viability and mitochondrial function. In addition, by upregulating B-cell lymphoma-2 (Bcl-2) and downregulating Bcl-2 associated X protein, FABP4 silencing improved LPS-induced anti-apoptosis of H9c2 cells. Finally, silencing FABP4 alleviated SIMD through the mTOR signaling pathway. However, the therapeutic effect was inhibited when FABP4 silencing was combined with the mTOR inhibitor AZD-8055.Conclusion:Silencing FABP4 alleviates LPS-induced inflammatory response and apoptosis in H9c2 cells and enhances mitochondrial function through the mTOR signaling pathway.

Cerebral ischemia/reperfusion (CIR) injury could lead to the function of brain cell disorder and cerebral infarction. MicroRNAs (miRNAs) have been reported to participate in the progression and protection of CIR injury. Thus, our study aimed to investigate the functional effects of microRNA-338-5p (miR-338-5p) on proliferation, apoptosis, and inflammatory response of CIR injury. According to the results, miR-338-5p was downregulated in the brain of the mice caused by CIR injury, and overexpression of miR-338-5p reduced the neurological deficit and infarct volume of the brain in the mice caused by CIR injury. Meanwhile, miR-338-5p overexpression promoted the proliferation, while suppressed the apoptosis and the inflammatory response of Neuro-2a cells exposed to hypoxia/reoxygenation (H/R). Interestingly, miR-338-5p directly targeted connective tissue growth factor (CTGF) and overexpression of CTGF reversed the functional effects of miR-338-5p on proliferation, apoptosis, and inflammatory response in Neuro-2a cells caused by H/R. More importantly, miR-338-5p affected the adenosine 5¢-monophosphate (AMP)-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) signaling pathway by regulating CTGF expression in Neuro-2a cells exposed to H/R. Taken together, we concluded that MiR-338-5p promoted the proliferation, while suppressed the apoptosis and the inflammatory response of cells exposed to H/R by targeting CTGF through the AMPK/mTOR signaling pathway.

Shikonin, a traditional Chinese medicine, has been identified as being capable of inducing apoptosis in various tumors, including glioma, and is thus considered to be a promising therapeutic agent for tumor therapy. However, little is known about the molecular mechanism of shikonin in glioma. The present study investigated the influence of shikonin on the proliferation and apoptosis of glioma cells U251 and U87MG and explored the potential molecular mechanisms. It was identified that shikonin was able to induce apoptosis in human glioma cells in a time- and dose-dependent manner, and a decreased expression level of cluster of differentiation (CD)147 was observed in shikonin-treated U251 and U87MG cells. Knockdown of CD147 inhibited U251 and U87MG cell growth, whereas CD147 overexpression enhanced cell growth and decreased shikonin-induced apoptosis. Additionally, an increased expression level of CD147 suppressed the elevated production of reactive oxygen species and mitochondrial membrane potential levels induced by shikonin. The data indicated that shikonin-induced apoptosis in glioma cells was associated with the downregulation of CD147 and the upregulation of oxidative stress. CD147 may be an optional target of shikonin-induced cell apoptosis in glioma cells.

Nuclear factor of activated T cells (NFAT), a family of transcription factors, has been implicated in many cellular processes, including some cancers. Here, we characterize, for the first time, the role of NFAT3 in doxorubicin (DOX)-mediated apoptosis, migration, and invasion in SNB19 and U87 glioma cells. This study demonstrates that the specific knockdown of NFAT3 results in a dramatic inhibition of the apoptotic effect induced by DOX and favors cell survival. Inhibition of NFAT3 activation by shNFAT3 (shNF3) significantly downregulated tumor necrosis factor (TNF)-alpha induction, its receptor TNFR1, caspase 10, caspase 3, and poly (ADP-ribose) polymerase, abrogating DOX-mediated apoptosis in glioma cells. DOX treatment resulted in NFAT3 translocation to the nucleus. Similarly, shNF3 treatment in SNB19 and U87 cells reversed DOX-induced inhibition of cell migration and invasion, as determined by wound healing and matrigel invasion assays. Taken together, these results indicate that NFAT3 is a prerequisite for the induction of DOX-mediated apoptosis in glioma cells.

One of the most fundamental aspects of growth in plants is its plasticity in relation to fluctuating environmental conditions. Growth of meristematic cells relies predominantly on protein synthesis, one of the most energy-consuming activities in cells, and thus is tightly regulated in accordance with the available nutrient and energy supplies. The Target of Rapamycin (TOR) signalling pathway takes a central position in this regulation. The core of the TOR signalling pathway is conserved throughout evolution, and can be traced back to the last eukaryotic common ancestor. In plants, a single complex constitutes the TOR signalling pathway. Manipulating the components of the TOR complex in Arabidopsis highlighted its common role as a major regulator of protein synthesis and metabolism, that is also involved in other biological functions such as cell-wall integrity, regulation of cell proliferation, and cell size. TOR, as an integral part of the auxin signalling pathway, connects hormonal and nutrient pathways. Downstream of TOR, S6 kinase and the ribosomal S6 protein have been shown to mediate several of these responses, although there is evidence of other complex non-linear TOR signalling pathway structures.