• Title, Summary, Keyword: Beclin-1

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Expression and Significance of Microsomal Prostaglandin Synthase-1 (mPGES-1) and Beclin-1 in the Development of Prostate Cancer

  • Xu, Lu-Wei;Qian, Ming;Jia, Rui-Peng;Xu, Zheng;Wu, Jian-Ping;Li, Wen-Cheng;Huang, Wen-Bin;Chen, Xing-Guo
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.4
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    • pp.1639-1644
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    • 2012
  • The aim of this study was to investigate the expression and significance of microsomal prostaglandin synthase-1 (mPGES-1) and Beclin-1 in the development of prostate cancer (PCa). Immunohistochemistry was performed on paraffin-embedded sections with rabbit polyclonal against mPGES-1 and Beclin-1 in 40 PCa, 40 benign prostatic hyperplasia (BPH) and 10 normal prostate specimens for this purpose. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied for mRNA expression of mPGES-1 and Beclin-1, while MTT assays were used to ascertain the best working concentration of the mPGES-1 inhibitor (CAY10526). The effect of CAY10526 treatment on expression of Beclin-1 in DU-145 cells was studied using Western blot analysis. Localization of Beclin-1 and mPGES-1 was in endochylema. Significant differences in expression was noted among PCa, BPH and normal issues (P<0.05). Beclin-1 expression inversely correlated with mPGES-1 expression in PCa tissue (P<0.05). CAY10526 could significantly block mPGES-1 expression and the proliferation of DU-145 cells (P<0.05), while increasing Beclin-1 levels (P<0.05). Overexpression of mPGES-1 could decrease the autophagic PCa cell death. Inhibiting the expression of mPGES-1 may lead to DU-145 cell death and up-regulation of Beclin-1. The results suggest that inhibition of mPGES-1 may have therapeutic potential for PCa in the future.

Prognostic Significance of Beclin-1 Expression in Colorectal Cancer: a Meta-analysis

  • Han, Ye;Xue, Xiao-Feng;Shen, Hu-Gang;Guo, Xiao-Bo;Wang, Xu;Yuan, Bin;Guo, Xing-Po;Kuang, Yu-Ting;Zhi, Qiao-Ming;Zhao, Hong
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.11
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    • pp.4583-4587
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    • 2014
  • Objective: Beclin-1 has recently been observed as an essential marker of autophagy in several cancers. However, the prognostic role of Beclin-1 in colorectal neoplasia remains controversial. Our study aimed to evaluate the potential association between Beclin-1 expression and the outcome of colorectal cancer patients. Materials and Methods: All related studies were systematically searched in Pubmed, Embase, Springer and Chinese National Knowledge Infrastructure databases (CNKI), and then a meta-analysis was performed to determine the association of Beclin-1 expression with clinical outcomes. Finally, a total of 6 articles were included in our analysis. Results: Our data showed that high Beclin-1 expression in patients with CRC was associated with poor prognosis in terms of tumor distant metastasis (OR=2.090, 95%CI=1.061-4.119, p=0.033) and overall survival (RR=1.422, 95%CI=1.032-1.959, p=0.031). However, we did not found any correlation between Beclin-1 over-expression and tumor differentiation (OR=1.711, 95%CI=0.920-3.183, p=0.090). In addition, there was no evidence of publication bias as suggested by Egger's tests for tumor distant metastasis (p=1.000), differentiation (p=1.000) and OS (p=0.308). Conclusions: Our present meta-analysis indicated that elevated Beclin-1 expression iss associated with tumor metastasis and a poor prognosis in patients with CRC. Beclin-1 might serve as an efficient prognostic indicator in CRC, and could be a new molecular target in CRC therapy.

Effect of Autophagy-Related Beclin1 on Sensitivity of Cisplatin-Resistant Ovarian Cancer Cells to Chemotherapeutic Agents

  • Sun, Yang;Liu, Jia-Hua;Jin, Long;Sui, Yu-Xia;Han, Li-Li;Huang, Yin
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.7
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    • pp.2785-2791
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    • 2015
  • The purpose of the study was to determine the effects of autophagy related gene Beclin1 at different levels of expression on the sensitivity of cisplatin-resistant ovarian cancer cells (SKOV3/DDP) to different chemotherapeutics. In pSUPER-Beclin1 transfected cells, real-time fluorescence quantitative RT-PCR and Western blot analysis showed that expression was significantly inhibited. Flow cytometry revealed that the mean fluorescence intensity (MDC), reflecting autophagy, and cells in the G0/G1 phase were markedly reduced. When compared with the blank control group, inhibition of Beclin1 expression in SKOV3/DDP cells not only increased the rate of apoptosis following treatment with chemotherapeutics, but also increased the sensitivity. These findings suggest that Beclin1 expression plays an important role in chemotherapeutic agent-induced death of SKOV3/DDP cells. Inhibition of autophagy related gene Beclin1 expression in SKOV3/DDP cells may increase the rate of apoptosis and elevate the sensitivity to chemotherapeutics.

Alternative Messenger RNA Splicing of Autophagic Gene Beclin 1 in Human B-cell Acute Lymphoblastic Leukemia Cells

  • Niu, Yu-Na;Liu, Qing-Qing;Zhang, Su-Ping;Yuan, Na;Cao, Yan;Cai, Jin-Yang;Lin, Wei-Wei;Xu, Fei;Wang, Zhi-Jian;Chen, Bo;Wang, Jian-Rong
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.5
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    • pp.2153-2158
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    • 2014
  • Beclin 1 is a key factor for initiation and regulation of autophagy, which is a cellular catabolic process involved in tumorigenesis. To investigate the role of alternative splicing of Beclin1 in the regulation of autophagy in leukemia cells, Beclin1 mRNA from 6 different types of cell lines and peripheral blood mononuclear cells from 2 healthy volunteers was reversely transcribed, subcloned, and screened for alternative splicing. New transcript variants were analyzed by DNA sequencing. A transcript variant of Beclin 1 gene carrying a deletion of exon 11, which encoded a C-terminal truncation of Beclin 1 isoform, was found. The alternative isoform was assessed by bioinformatics, immunoblotting and subcellular localization. The results showed that this variable transcript is generated by alternative 3' splicing, and its translational product displayed a reduced activity in induction of autophagy by starvation, indicating that the spliced isoform might function as a dominant negative modulator of autophagy. Our findings suggest that the alternative splicing of Beclin 1 might play important roles in leukemogenesis regulated by autophagy.

Bacterial Overexpression and Denaturing Purification of VPS34-Binding Domain of Beclin 1

  • Baek, Jong-Hyuk;Jung, Juneyoung;Seo, Jeongbin;Kim, Jeong Hee;Kim, Joungmok
    • Journal of Microbiology and Biotechnology
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    • v.26 no.10
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    • pp.1808-1816
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    • 2016
  • As a scaffolding subunit of the PIK3C3/VPS34 complex, Beclin 1 recruits a variety of proteins to class III phosphatidylinositol-3-kinase (VPS34), resulting in the formation of a distinct PIK3C3/VPS34 complex with a specific function. Therefore, the investigation of a number of Beclin 1 domains required for the protein-protein interactions will provide important clues to understand the PIK3C3/VPS34 complex, of which Beclin1-VPS34 interaction is the core unit. In the present study, we have designed a bacterial overexpression system for the Beclin 1 domain corresponding to VPS34 binding (Vps34-BD) and set up the denaturing purification protocol due to the massive aggregation of Vps34-BD in Escherichia coli. The expression and purification conditions determined in this study successfully provided soluble and functional Vps34-BD.

Over-Expression of Beclin-1 Facilitates Acquired Resistance to Histone Deacetylase Inhibitor-Induced Apoptosis

  • Wang, Shi-Miao;Li, Xiao-Hui;Xiu, Zhi-Long
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.18
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    • pp.7913-7917
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    • 2014
  • Apoptotic cell death plays a predominant role in histone deacetylase (HDAC) inhibitor-induced cytotoxicity. Nuclear morphological changes and activation of apoptotic executors are involved in CTS203-induced cell death. However, emerging issues of HDAC inhibitor-resistance have been observed in patients. Herein, MCF-7 cells were continuously exposed to CTS203 until the derived cells could proliferate normally in its presence. The newly obtained CTS203-resistant cells were nominated as MCF-7/203R. Compared to MCF-7 original cells, the MCF-7/203R cells were less sensitive to CTS203-induced apoptosis, with a minimal 6-fold higher $IC_{50}$ value. In contrast, the expression of Beclin-1 was dramatically up-regulated, positively correlated to the acquisition of CTS203-resistance. Our results revealed the participation of autophagy in acquired HDAC inhibitor-resistance and further identified Beclin-1 as a promising target for anti-drug resistance.

Autophagy-related protein LC3 and Beclin-1 in the first trimester of pregnancy

  • Chifenti, Barbara;Locci, Maria Teresa;Lazzeri, Gloria;Guagnozzi, Mariangela;Dinucci, Dino;Chiellini, Federica;Filice, Maria Elena;Salerno, Maria Giovanna;Battini, Lorella
    • Clinical and Experimental Reproductive Medicine
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    • v.40 no.1
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    • pp.33-37
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    • 2013
  • Autophagy is a degradation process that acts in response to environmental stressors. Recently, autophagy has been detected in normal term, preeclamptic and intrauterine growth-restricted placentas. The object of this work was to investigate the presence of autophagy in first trimester voluntary interruption of pregnancy placental villi by the expression of autophagy-related proteins, light chain 3 (LC3), and Beclin-1. In first trimester placental villi laser scanning confocal microscopy (LSCM) analysis revealed LC3 and Beclin-1 immunoreactivity prevalently located in villous cytotrophoblasts. Using LSCM, LC3, and Beclin-1 were localized to the cytoplasm of the trophoblast layer in human full-term placentas. Beclin-1 expression and LC3 activation were confirmed by western blotting. These data emphasize that autophagy activation is different among cytotrophoblasts and syncytiotrophoblasts depending on the gestational age and thus we speculate that autophagy might play a prosurvival role throughout human pregnancy.

ZFP36L1 and AUF1 Induction Contribute to the Suppression of Inflammatory Mediators Expression by Globular Adiponectin via Autophagy Induction in Macrophages

  • Shrestha, Aastha;Pun, Nirmala Tilija;Park, Pil-Hoon
    • Biomolecules & Therapeutics
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    • v.26 no.5
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    • pp.446-457
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    • 2018
  • Adiponectin, a hormone predominantly originated from adipose tissue, has exhibited potent anti-inflammatory properties. Accumulating evidence suggests that autophagy induction plays a crucial role in anti-inflammatory responses by adiponectin. However, underlying molecular mechanisms are still largely unknown. Association of Bcl-2 with Beclin-1, an autophagy activating protein, prevents autophagy induction. We have previously shown that adiponectin-induced autophagy activation is mediated through inhibition of interaction between Bcl-2 and Beclin-1. In the present study, we examined the molecular mechanisms by which adiponectin modulates association of Bcl-2 and Beclin-1 in macrophages. Herein, we demonstrated that globular adiponectin (gAcrp) induced increase in the expression of AUF1 and ZFP36L1, which act as mRNA destabilizing proteins, both in RAW 264.7 macrophages and primary peritoneal macrophages. In addition, gene silencing of AUF1 and ZFP36L1 caused restoration of decrease in Bcl-2 expression and Bcl-2 mRNA half-life by gAcrp, indicating crucial roles of AUF1 and ZFP36L1 induction in Bcl-2 mRNA destabilization by gAcrp. Moreover, knock-down of AUF1 and ZFP36L1 enhanced interaction of Bcl-2 with Beclin-1, and subsequently prevented gAcrp-induced autophagy activation, suggesting that AUF1 and ZFP36L1 induction mediates gAcrp-induced autophagy activation via Bcl-2 mRNA destabilization. Furthermore, suppressive effects of gAcrp on LPS-stimulated inflammatory mediators expression were prevented by gene silencing of AUF1 and ZFP36L1 in macrophages. Taken together, these results suggest that AUF1 and ZFP36L1 induction critically contributes to autophagy induction by gAcrp and are promising targets for anti-inflammatory responses by gAcrp.

Src Family Kinase Inhibitor PP2 Induces LC3 Conversion in a Manner That is Uncoupled from Autophagy and Increases Apoptosis in Multidrug-Resistant Cells

  • Kim, Yun-Ki;Ahn, Jun-Ho;Lee, Mi-Chael
    • Biomolecules & Therapeutics
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    • v.20 no.4
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    • pp.393-398
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    • 2012
  • Recently, we reported that defective autophagy may contribute to the inhibition of the growth in response to PP2 (4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine), a selective SFK inhibitor, in multidrug-resistant v-Ha-ras-transformed NIH 3T3 cells (Ras-NIH 3T3/Mdr). In this study, we demonstrated that PP2 induces LC3 conversion via a mechanism that is uncoupled from autophagy and increases apoptosis in Ras-NIH 3T3/Mdr cells. PP2 preferentially induced autophagy in Ras-NIH 3T3 cells rather than in Ras-NIH 3T3/Mdr cells as determined by LC3-I to LC3-II conversion and GFP-LC3 fluorescence microscopy. Beclin 1 knockdown experiments showed that, regardless of drug resistance, PP2 induces autophagy via a Beclin 1-dependent mechanism. PP2 induced a conformational change in Beclin 1, resulting in the enhancement of the pro-autophagic activity of Beclin 1, in Ras-NIH 3T3 cells. Further, PI3K inhibition induced by wortmannin caused a significant increase in apoptosis in Ras-NIH 3T3 cells, as demonstrated by flow cytometric analysis of Annexin V staining, implying that autophagy inhibition through PI3K increases apoptosis in response to PP2 in Ras-NIH 3T3 cells. However, despite the fact that wortmannin abrogates PP2-induced GFP-LC3 punctae formation, some LC3 conversion remains in Ras-NIH 3T3/Mdr cells, suggesting that LC3 conversion may occur in an autophagy-independent manner. Taken together, these results suggest that PP2 induces LC3 conversion independent of PI3K, concomitant with the uncoupling of LC3 conversion from autophagy, in multidrug-resistant cells.

29-kDa FN-f inhibited autophagy through modulating localization of HMGB1 in human articular chondrocytes

  • Hwang, Hyun Sook;Choi, Min Ha;Kim, Hyun Ah
    • BMB Reports
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    • v.51 no.10
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    • pp.508-513
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    • 2018
  • Fibronectin fragments found in the synovial fluid of patients with osteoarthritis (OA) induce the catabolic responses in cartilage. Nuclear high-mobility group protein Box 1 (HMGB1), a damage-associated molecular pattern, is responsible for the regulation of signaling pathways related to cell death and survival in response to various stimuli. In this study, we investigated whether changes induced by 29-kDa amino-terminal fibronectin fragment (29-kDa FN-f) in HMGB1 expression influences the pathogenesis of OA via an HMGB1-modulated autophagy signaling pathway. Human articular chondrocytes were enzymatically isolated from articular cartilage. The level of mRNA was measured by quantitative real-time PCR. The expression of proteins was examined by western blot analysis, immnunofluorescence assay, and enzyme-linked immunosorbent assay. Interaction of proteins was evaluated by immunoprecipitation. The HMGB1 level was significantly lower in human OA cartilage than in normal cartilage. Although 29-kDa FN-f significantly reduced the HMGB1 expression at the mRNA and protein levels 6 h after treatment, the cytoplasmic level of HMGB1 was increased in chondrocytes treated with 29-kDa FN-f, which significantly inhibited the interaction of HMGB1 with Beclin-1, increased the interaction of Bcl-2 with Beclin-1, and decreased the levels of Beclin-1 and phosphorylated Bcl-2. In addition, the level of microtubule-associated protein 1 light chain 3-II, an autophagy marker, was down-regulated in chondrocytes treated with 29-kDa FN-f, whereas the effect was antagonized by mTOR knockdown. Furthermore, prolonged treatment with 29-kDa FN-f significantly increased the release of HMGB1 into the culture medium. These results demonstrated that 29-kDa FN-f inhibits chondrocyte autophagy by modulating the HMGB1 signaling pathway.