BECN1

Gene Summary

Gene:BECN1; beclin 1
Aliases: ATG6, VPS30, beclin1
Location:17q21.31
Summary:This gene encodes a protein that regulates autophagy, a catabolic process of degradation induced by starvation. The encoded protein is a component of the phosphatidylinositol-3-kinase (PI3K) complex which mediates vesicle-trafficking processes. This protein is thought to play a role in multiple cellular processes, including tumorigenesis, neurodegeneration and apoptosis. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Sep 2015]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:beclin-1
Source:NCBIAccessed: 11 March, 2017

Ontology:

What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 11 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 11 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (4)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: BECN1 (cancer-related)

Wang YF, Xu YL, Tang ZH, et al.
Baicalein Induces Beclin 1- and Extracellular Signal-Regulated Kinase-Dependent Autophagy in Ovarian Cancer Cells.
Am J Chin Med. 2017; 45(1):123-136 [PubMed] Related Publications
Baicalein (BA), one of the major compounds isolated from the root of Scutellaria baicalensis Gerogi, exhibits various pharmacological effects, such as anti-oxidant, anti-inflammatory, and anticancer effects. In this study, we found that BA reduced cell viability and increased apoptosis in ovarian cancer cells. Treatment of cells with BA enhanced microtubule-associated protein light chain 3-II (LC3-II) expression, acidic vesicular organelle and GFP-LC3 fluorescence dot accumulation. Combined treatment with chloroquine and BA apparently reduced cell viability and increased the cleavage of poly (ADPribose) polymerase (PARP) in both HEY and A2780 ovarian cancer cell lines, indicating that BA induces a protective autophagy in these cells. Knockdown of Beclin 1 by siRNA remarkably decreased BA-induced LC3-II lipidation. In addition, we found an increase in the phosphorylation of extracellular signal-regulated kinase (ERK, Thr202/Thr204) and AKT (Ser473) after BA treatment, and inhibition of ERK activation by the pharmacological inhibitor U0126 or ERK siRNA blocked BA-induced autophagy. Taken together, these results suggest that BA induces Beclin 1- and ERK-dependent autophagy in ovarian cancer cells.

He ZJ, Zhu FY, Li SS, et al.
Inhibiting ROS-NF-κB-dependent autophagy enhanced brazilin-induced apoptosis in head and neck squamous cell carcinoma.
Food Chem Toxicol. 2017; 101:55-66 [PubMed] Related Publications
Autophagy modulation has been considered a potential therapeutic strategy for head and neck squamous cell carcinoma (HNSCC). A previous study confirmed that brazilin might possess significant anti-carcinogenic activity. However, whether brazilin induces autophagy and its roles in cell death in HNSCC are still unclear. In this study, we have shown that brazilin induced significant apoptosis in the Cal27 HNSCC cell line but not in oral keratinocyte cell line (OKC). In addition to showing apoptosis induction, we demonstrated the brazilin-induced autophagic response in the Cal27 cells, as evidenced by the formation of GFP-LC3 puncta, and also showed the upregulation of LC3-II and Beclin-1. Moreover, pharmacologically or genetically blocking autophagy enhanced the brazilin-induced apoptosis, indicating the cytoprotective role of autophagy in brazilin-treated Cal27 cells. Moreover, brazilin activated nuclear factor kappa B (NF-κB p65) nuclear translocation and increased NF-κB p65 reporter activity, which contributed to the upregulation of autophagy-related genes, including LC3-II and Beclin-1. Importantly, we found that brazilin triggered reactive oxygen species (ROS) generation in Cal27 cells. Furthermore, N-acetyl-cysteine (NAC), a ROS scavenger, abrogated the effects of brazilin on the NF-κB p65-dependent autophagy. Taken together, our results demonstrated that brazilin increased the NF-κB p65-dependent autophagy through the promotion of ROS signalling pathways in HNSCC. These data also suggest that a strategy of blocking ROS-NF-κB p65-dependent autophagy to enhance the activity of brazilin warrants further attention for the treatment of HNSCC.

Chang CD, Lin PY, Hsu JL, Shih WL
Ursolic Acid Suppresses Hepatitis B Virus X Protein-mediated Autophagy and Chemotherapeutic Drug Resistance.
Anticancer Res. 2016; 36(10):5097-5107 [PubMed] Related Publications
Hepatitis B virus X (HBx) protein is a multifunctional oncoprotein that affects diverse cell activities via regulation of various host cell signaling pathways. The current investigation demonstrated that ursolic acid (UA), a pentacyclic triterpenoid, protected hepatoma cells and reduced HBx-mediated autophagy through modulation of Ras homolog gene family member A (RhoA). Low-level ectopic HBx expression in Huh7 cells induced more significant autophagosome formation than high-level HBx expression. HBx activated beclin-1 promoter and enhanced the beclin-1 protein expression under low HBx expression. Transcription factor AP-1 played an essential function in HBx-mediated beclin-1 promoter activation. Inhibition of RhoA and its downstream effector Rho-associated coiled-coil-containing protein kinase 1 (ROCK1) alleviated HBx-mediated autophagy significantly. Transiently-expressed HBx elicited an increased RhoA-GTP level, as well as phospho-ROCK1 transient accumulation. Utilization of transactivation-deficient HBx demonstrated that the transactivation activity of HBx is required for autophagy induction. Furthermore, UA suppressed HBx-mediated RhoA activation, beclin-1 promoter activation and subsequent autophagy induction, while, most importantly, reversed HBx-induced anti-cancer drug resistance.

Yu Y, Hou L, Song H, et al.
Akt/AMPK/mTOR pathway was involved in the autophagy induced by vitamin E succinate in human gastric cancer SGC-7901 cells.
Mol Cell Biochem. 2017; 424(1-2):173-183 [PubMed] Related Publications
Vitamin E succinate (VES), a derivative of vitamin E, is a promising cancer chemopreventive agent that inhibits tumor promotion by inducing apoptotic cell death. The effects of VES on autophagy, an intricate programmed process which helps cells survive in some stressed situations by degrading some cytoplasmic material, are unclear. When human gastric cancer cells SCG-7901 were exposed to VES, both the level of microtubule-associated protein 1 light chain 3 and the yeast ATG6 homolog Beclin-1 increased, and related autophagy genes were activated, thereby suggesting that autophagy was induced by VES. We also observed that VES-induced autophagy was accompanied by the activation of AMP-activated protein kinases (AMPK). VES-induced autophagy decreased when AMPK was inhibited by using small interfering RNA (siRNA), thereby suggesting that VES-induced autophagy is mediated by AMPK. Moreover, further studies revealed that the decreased activity of mammalian target of rapamycin (mTOR) and its downstream targets P70S6K and 4EBP-1 were involved in VES-activated autophagy associated with AMPK activation. The experiments also showed that the activity of protein kinases B (Akt)-mTOR axis was inhibited by VES. VES-induced AMPK activation could be attenuated by Akt activation. Overall, our studies demonstrated that AMPK was involved in the VES-induced autophagy. Crosstalk exists between AMPK and the Akt/mTOR axis. The results elucidated the mechanism of VES-induced autophagy in human gastric cancer cells.

Ji GH, Cui Y, Yu H, Cui XB
Profiling analysis of FOX gene family members identified FOXE1 as potential regulator of NSCLC development.
Cell Mol Biol (Noisy-le-grand). 2016; 62(11):57-62 [PubMed] Related Publications
Lung cancer is one of the most malignant tumors worldwide with a high mortality rate, which has not been improved since several decades ago. FOX gene family members have been reported to play extensive roles in regulating many biological processes and disorders. In order to clarify the contribution of FOX gene family members in lung cancer biology, we performed expression profiling analysis of FOX gene family members from FOXA to FOXR in lung cancer cell lines and tissue specimens by Real-time PCR, western blot and immunohistochemistry analysis. We found that FOXE1 was the only gene which was over-expressed in six out of eight lung cancer cell lines and human cancer tissue specimens (28 out of 35 cases with higher expression and 7 out of 35 cases with moderate expression). Further investigation showed that MMP2 gene was up-regulated, and autophagy markers such as LC3B, ATG5, ATG12 and BECLIN1, were down-regulated concomitant with the increase of FOXE1. These results implicated that FOXE1 may be an important regulator by targeting autophagy and MMPs pathways in lung cancer development.

Wu X, Feng X, Zhao X, et al.
Role of Beclin-1-Mediated Autophagy in the Survival of Pediatric Leukemia Cells.
Cell Physiol Biochem. 2016; 39(5):1827-1836 [PubMed] Related Publications
BACKGROUND/AIMS: Acute and chronic leukemia are severe malignant cancers worldwide, and can occur in pediatric patients. Since bone marrow cell transplantation is seriously limited by the availability of the immune-paired donor sources, the therapy for pediatric leukemia (PL) remains challenging. Autophagy is essential for the regulation of cell survival in the harsh environment. However, the role of autophagy in the survival of PL cells under the oxidative stress, e.g. chemotherapy, remain ill-defined. In the current study, we addressed these questions.
METHODS: We analyzed the effects of oxidative stress on the cell viability of PL cells in vitro, using a CCK-8 assay. We analyzed the effects of oxidative stress on the apoptosis and autophagy of PL cells. We analyzed the levels of Beclin-1 and microRNA-93 (miR-93) in PL cells. Prediction of binding between miR-93 and 3'-UTR of Beclin-1 mRNA was performed by a bioinformatics algorithm and confirmed by a dual luciferase reporter assay. The relationship between levels of miR-93 and patients' survival was analyzed in PL patients.
RESULTS: We found that oxidative stress dose-dependently increased autophagy in PL cells. While low-level oxidative stress did not increase apoptosis, high-level oxidative stress increased apoptosis, seemingly from failure of autophagy-mediated cell survival. High-level oxidative stress appeared to suppress the protein levels of an autophagy protein Beclin-1 in PL cells, possibly through induction of miR-93, which inhibited the translation of Beclin-1 mRNA via 3'-UTR binding.
CONCLUSION: Beclin-1-mediated autophagy plays a key role in the survival of PL cells against oxidative stress. Induction of miR-93 may increase the sensitivity of PL cells to oxidative stress during chemotherapy to improve therapeutic outcome.

Zhang F, Wang B, Long H, et al.
Decreased miR-124-3p Expression Prompted Breast Cancer Cell Progression Mainly by Targeting Beclin-1.
Clin Lab. 2016; 62(6):1139-45 [PubMed] Related Publications
BACKGROUND: Recent findings have revealed that abnormal expression of microRNAs (miRNA, miR) contributes to the malignancies of various cancers. Here, we report a novel miRNA that regulates the expression of Beclin-1 in breast cancer cells.
METHODS: The expression of miR-124-3p and Beclin-1 was identified in breast cancer tissues and breast cancer cell lines. To explore whether Beclin-1 was the target gene of miR-124-3p, luciferase reporter assay was applied. MIR-124-3p was overexpressed or inhibited with the corresponding mimics or inhibitors. The expression of autophagy-related proteins including Beclin-1 and LC3II were explored by western blot and quantitative real-time PCR.
RESULTS: We first demonstrated that miR-124-3p was decreased in breast cancer tissues and breast cancer cells lines. Furthermore, we validated that miR-124-3p could negatively regulate the expression of Beclin-1. Increased miR-124-3p significantly decreased the expression of Beclin-1 and LC3I. Further study showed that overexpres- sion of miR-124-3p could partially reverse 4-hydroxytamoxifen (4-OHT)-induced autophagy in breast cancer cells.
CONCLUSIONS: Decreased miR-124-3p expression prompted breast cancer cell progression mainly by enhancing the expression of autophagy related protein, Beclin-1.

Pirtoli L, Belmonte G, Toscano M, et al.
Cyclin D1 Co-localizes with Beclin-1 in Glioblastoma Recurrences: A Clue to a Therapy-induced, Autophagy-mediated Degradative Mechanism?
Anticancer Res. 2016; 36(8):4057-62 [PubMed] Related Publications
BACKGROUND: Glioblastoma (GB) recurrences are rarely removed, therefore, tissue modifications induced by radiotherapy, and temozolomide chemotherapy are scarcely known. Nuclear cyclin D1 is associated with GB progression and resistance to therapy. We previously found that the expression of autophagic protein beclin-1 is a major determinant of prognosis in GB.
PATIENTS AND METHODS: In 31 patients with primary GB and their recurrences, we investigated the protein expression of cyclin D1 and beclin-1, before and after radiotherapy-temozolomide therapy by immunohistochemistry.
RESULTS: Most (20/31) primary GBs were negative for nuclear cyclin D1, and highly expressed beclin-1. In their recurrences, cytoplasmic cyclin D1 positivity was observable, which co-localized with beclin-1. Eleven primary GBs instead exhibited low beclin-1 expression and were positive for nuclear cyclin D1; three of their recurrences exhibited an increase of beclin-1, which co-localized with cyclin D1 in the cytoplasm.
CONCLUSION: Our results suggest therapy-induced degradation of cyclin D1 via autophagy.

Zhao G, Ge T, Yang X, Li X
The direct anti-cancer efficacy of Sapylin on breast cancer cells in vitro and in vivo.
Hell J Nucl Med. 2016 May-Aug; 19(2):111-7 [PubMed] Related Publications
OBJECTIVE: On the basis of our previous study in which we studied cancer cells under in vitro and in vivo hypoxia conditions, we have now investigated the anti-cancer efficacy of Sapylin on breast cancer cells in mice and human.
MATERIALS AND METHODS: We used different concentrations of Sapylin and the three kinds of breast cancer cells. We used water-soluble tetrazolium salt cell proliferation test (WST-1) to detect changes in cell proliferation and Fluorescein Iothiocyanate-Propidium Iodide (Anexin V FITC-PI) to detect changes in the rate of apoptosis by flow cytometry. We also used reverse transcription-polymerase chain reaction (RT-PCR) to detect possible changes of mRNA expression and used western blot in order to test changes related to protein expression that could lead to cell death. The anti-tumor effect was studied by locally injecting Sapylin into an animal tumor model of breast cancer. We also studied the possible postoperative adverse clinical side effects in 60 female breast cancer patients, stage II-III, aged 25-55 years. The patients underwent a modified, radical operation with smooth incisions which healed well.
RESULTS: Sapylin was able to inhibit by 10%-15% the proliferation of all three kinds of breast cancer cells and also to present positive correlation in vivo with some phenomenona which were time and concentration dependent. After applying Sapylin for 48h, the apoptosis rate was significantly increased by 12%-20%. Apoptosis of breast cancer cells may be related to biological effects supporting cells survival, through B-cell lymphoma gene 2 (Bcl-2nd) Ki67 mRNA expression descent and Bcl-2 associated X Protein (Bax mRNA) expression. This process ultimately promotes cell death. At the same time this process also showed a significant anti-tumor effect (50%-60%) in a mice model. We found no significant adverse reactions, the patients had no significant pain and the postoperative wound was partially healed. After 5 days, the drainage was well reduced and remained so more in the study group than in the control group at a range of 20%-30% (P<0.05).
CONCLUSION: In our research, Sapylin displayed a strong direct anti-cancer effect in breast cancer cells and supported postoperative recovery. Clinically we noticed an obvious reduction of drainage in contrast with the control group.

Zhang Z, Tian H, Miao Y, et al.
Upregulation of p72 Enhances Malignant Migration and Invasion of Glioma Cells by Repressing Beclin1 Expression.
Biochemistry (Mosc). 2016; 81(6):574-82 [PubMed] Related Publications
p72 is the member of the DEAD-box RNA helicase family, which can unwind double-stranded RNA and is efficient for microRNA (miRNA, miR) processing. However, its specific role in glioma has not been elucidated. First, the expression of p72 in glioma cell lines and tissues was explored using Western blot. To explore the role of p72 on glioma progression, adenovirus inhibiting p72 was transfected into A172 and T98G cells. Cell autophagy was determined using GFP-LC3 dots, and cell apoptosis was determined using flow cytometry. The effect of Beclin1 was explored using GFP-LC3 dots, flow cytometry, and colony formation. The possible miRNAs that target the 3'-untranslated region (3'-UTR) of Beclin1 were predicted using TargetScan. Dual luciferase reporter assay was applied to determine whether these miRNAs bind to the 3'-UTR of Beclin1. The expression of p72 was significantly increased in glioma cell lines and tissues. Autophagy-related protein Beclin1 was found to be significantly enhanced when p72 was inhibited. The accumulation of GFP-LC3 dots was significant in cells transfected with ad-sh-p72 compared with ad-con. Colony formation capacity and cell apoptosis were also found to be significantly decreased with p72 inhibition. Furthermore, upregulation of Beclin1 contributes to A172 cell autophagy, invasion, and apoptosis. Overexpression of p72 induces increased miR-34-5p and miR-5195-3p expression in A172 and T98G cells. Beclin1 was the target gene of miR-34-5p and miR-5195-3p. In conclusion, we found for the first time that overexpression of p72 decreased Beclin1 expression partially by increasing miR-34-5p and miR-5195-3p expression in A172 and T98G cells.

Yang XJ, Si RH, Liang YH, et al.
Mir-30d increases intracellular survival of Helicobacter pylori through inhibition of autophagy pathway.
World J Gastroenterol. 2016; 22(15):3978-91 [PubMed] Free Access to Full Article Related Publications
AIM: To determine if mir-30d inhibits the autophagy response to Helicobacter pylori (H. pylori) invasion and increases H. pylori intracellular survival.
METHODS: The expression of mir-30d was detected by quantitative polymerase chain reaction (PCR), and autophagy level was examined by transmission electron microscopy, western blot, and GFP-LC3 puncta assay in human AGS cells and GES-1 cells. Luciferase reporter assay was applied to confirm the specificity of mir-30d regulation on the expression of several core molecules involved in autophagy pathway. The expression of multiple core proteins were analyzed at both the mRNA and protein level, and the intracellular survival of H. pylori after different treatments was detected by gentamicin protection assay.
RESULTS: Autophagy level was increased in AGS and GES-1 cells in response to H. pylori infection, which was accompanied by upregulation of mir-30d expression (P < 0.05, vs no H. pylori infection). In the two gastric epithelial cell lines, mimic mir-30d was found to repress the autophagy process, whereas mir-30d inhibitor increased autophagy response to H. pylori invasion. mir-30d mimic decreased the luciferase activity of wild type reporter plasmids carrying the 3' untranslated region (UTR) of all five tested genes (ATG2B, ATG5, ATG12, BECN1, and BNIP3L), whereas it had no effect on the mutant reporter plasmids. These five genes are core genes of autophagy pathway, and their expression was reduced significantly after mir-30d mimic transfection (P < 0.05, vs control cells without mir-30d mimic treatment). Mir-30d mimic transfection and direct inhibition of autophagy increased the intracellular survival of H. pylori in AGS cells.
CONCLUSION: Mir-30d increases intracellular survival of H. pylori in gastric epithelial cells through inhibition of multiple core proteins in the autophagy pathway.

Abdel-Mohsen MA, Ahmed OA, El-Kerm YM
BRCA1 Gene Mutations and Influence of Chemotherapy on Autophagy and Apoptotic Mechanisms in Egyptian Breast Cancer Patients.
Asian Pac J Cancer Prev. 2016; 17(3):1285-92 [PubMed] Related Publications
BACKGROUND: It is well established that mutations in the BRCA1 gene are a major risk factor for breast cancer. Induction of cancer cell death and inhibition of survival are the main principles of cancer therapy. In this context, autophagy may have dual roles in cancer, acting on the one hand as a tumor suppressor and on the other as a mechanism of cell survival that can promote the growth of established tumors. Therefore, understanding the role of autophagy in cancer treatment is critical. Moreover, defects in apoptosis, programmed cell death, may lead to increased resistance to chemotherapy.
PURPOSE: The aim of the present study was to detect BRCA1 gene mutations in order to throw more light on their roles as risk factors for breast cancer in Egypt. Secondly the role of autophagy and apoptosis in determining response to a fluorouracil, doxorubicin, cyclophosphamide (FAC) regimen was investigated.
MATERIALS AND METHODS: Forty-five female breast cancer cases and thirty apparently healthy females were enrolled in the present study. Serum levels of autophagic biomarkers, Beclin 1 and LC3 as well as the serum levels of apoptosis biomarkers Bcl-2 and Caspase-3 were measured before and after chemotherapy.
RESULTS: BRCA1 mutations were found in 5 (16.7%) and 44 (99.8%) of the controls and cancer patients, the most frequent being 5382insC followed by C61G and 185 delAG. The results revealed that chemotherapy caused elevation in serum concentration levels of the autophagic biomarkers (Beclin 1 and LC3). This elevation was associated with a significant decrease in serum concentration levels of Bcl-2 and significant increase in caspase-3 concentration levels (apoptotic markers).
CONCLUSIONS: The results of the present study indicate a very high level of BRCA mutations in breast cancer cases in Egypt and point to involvement of autophagic and apoptotic machinery activation in response to FAC chemotherapy.

Zhang Z, Wu B, Chai W, et al.
Knockdown of WAVE1 enhances apoptosis of leukemia cells by downregulating autophagy.
Int J Oncol. 2016; 48(6):2647-56 [PubMed] Related Publications
Chemoresistance of leukemia constitutes a great challenge for successful treatment of leukemia. Autophagy has recently attracted increasing attention for its role in conferring resistance to various conventional anti-neoplastic regiments. In the present study, the authors showed that WAVE1, a member of WASP family verprolin-homologous proteins, is a critical regulator of chemoresistance during autophagy. It is positively correlated with clinical status in pediatric acute myeloblastic leukemia (AML) and leukemia cell lines. The knockdown of WAVE1 expression decreased autophagy was accompanied by an upregulation of autophagic marker microtubule-associated protein light chain 3 (LC3)-Ⅱ, a degradation of SQSTM1/sequestosome 1 (p62) and the formation of autophagosomes. Moreover, a suppression of WAVE1 expression increased the sensitivity of leukemia cells to chemotherapy and apoptosis, and depletion of WAVE1 expression promoted the translocation of Bcl-2 from mitochondria into the cytoplasm. In addition, a knockdown of PI3K-Ⅲ expression significantly inhibited WAVE1-mediated autophagy. Furthermore, suppression of WAVE1 expression blocked the interactions between Beclin1 and PI3K-Ⅲ and the disassociation of Beclin1-Bcl-2 during enhanced autophagy. The above results suggested that WAVE1 is a critical pro-autophagic protein capable of enhancing cell survival and regulating chemoresistance in leukemia cells potentially through the Beclin1/Bcl-2 and Beclin1/PI3K-Ⅲ complex-dependent pathways.

Qin L, Xu T, Xia L, et al.
Chloroquine enhances the efficacy of cisplatin by suppressing autophagy in human adrenocortical carcinoma treatment.
Drug Des Devel Ther. 2016; 10:1035-45 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: It has been demonstrated that chloroquine (CQ) enhances the efficacy of chemotherapy. However, little is known about whether CQ could enhance the efficacy of cisplatin (DDP) in the treatment of adrenocortical carcinoma (ACC). In this study, we explore the efficacy and mechanism by which CQ affects DDP sensitivity in human ACC in vitro and in vivo.
METHODS: The autophagic gene Beclin-1 expression was detected by immunohistochemistry, and the protein levels were analyzed using immunoblotting assays of ACC tissues and normal adrenal cortex tissues. The ACC SW13 cells were treated with DDP and/or CQ. The cell viability assay was performed using the MTT method. Qualitative autophagy detection was performed by monodansylcadaverine staining of autophagic vacuoles. Annexin V-fluorescein isothiocyanate/propidium iodide double staining was used to count cell apoptosis by flow cytometry. The autophagy-related protein (Beclin-1, LC3, and p62) and apoptosis relative protein (Bax and Bcl-2) levels were evaluated with Western blot analysis. Furthermore, a murine model of nude BALB/c mice bearing SW13 cell xenografts was established to evaluate the efficacy of concomitant therapy.
RESULTS: The expression of the autophagic gene Beclin-1 was significantly downregulated in ACC tissues compared to normal adrenal cortex tissues. The Beclin-1 protein level in ACC tissues was lower than that in normal adrenal cortex tissues (P<0.05). In vitro concomitant therapy (DDP and CQ) was more effective in restraining SW13 cell proliferation. DDP could promote cell apoptosis and induce autophagy in SW13 cells. Concomitant therapy further promoted cell apoptosis by inhibiting autophagy. In vivo, we found that concomitant therapy was more potent than DDP monotherapy in inhibiting the growth of xenografted tumors and prolonging the survival of tumor-bearing mice.
CONCLUSION: The antitumor ability of DDP was related to autophagy activity, and the concomitant therapy (DDP and CQ) could be an optimal strategy for treating ACC.

Radwan SM, Hamdy NM, Hegab HM, El-Mesallamy HO
Beclin-1 and hypoxia-inducible factor-1α genes expression: Potential biomarkers in acute leukemia patients.
Cancer Biomark. 2016; 16(4):619-26 [PubMed] Related Publications
BACKGROUND: Beclin-1, an important autophagic gene, and hypoxia-inducible factor-1α (HIF-1α), the master regulator of the hypoxic response, are reported in several human cancers. However, their expressions in acute leukemia haven't yet been well investigated.
OBJECTIVE: This study was designed to investigate the gene expression of beclin-1, microtubule-associated protein-1 light chain-3B (MAB1LC3B), the anti-apoptotic marker Bcl-2, and HIF-1α, as well as to evaluate the relationship between their expressions profile and prognosis in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) adult patients.
METHODS: The study involved 30 AML patients, 25 ALL patients, and 20 controls. Gene expression was analyzed using quantitative reverse transcriptase polymerase chain reaction (QRT-PCR).
RESULTS: In both AML and ALL groups, beclin-1 and MAB1LC3B expressions were significantly down-regulated (p < 0.001), while HIF-1α (p < 0.01) and Bcl-2 (p < 0.001) expressions were significantly up-regulated compared to the control group. HIF-1α fold expression was significantly negatively correlated with beclin-1 (p < 0.01). Moreover, decreased beclin-1 gene expression and increased HIF-1α gene expression were both associated with poor survival, supporting their pivotal role in the development and progression of acute leukemia.
CONCLUSIONS: Both Beclin-1 and HIF-1α could be considered as important biomarkers determinants of pathogenesis and survival in acute leukemia.

Ueno T, Saji S, Sugimoto M, et al.
Clinical significance of the expression of autophagy-associated marker, beclin 1, in breast cancer patients who received neoadjuvant endocrine therapy.
BMC Cancer. 2016; 16:230 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Neoadjuvant endocrine therapy (NAE) has been employed to improve surgical outcomes for hormone receptor-positive breast cancers in postmenopausal women. Endocrine responsiveness is estimated by expressions of hormone receptors, but its heterogeneity has been recognized. Autophagy is an evolutionally conserved process associated with cell survival and cell death and has been implicated in cancer treatment.
METHODS: In order to examine the possible association between autophagy and response to endocrine therapy, we evaluated the status of autophagy-associated markers, beclin 1 and LC3, and apoptosis-associated markers, TUNEL and M30, in pre- and post-treatment specimens from 71 patients in a multicenter prospective study of neoadjuvant exemestane (JFMC34-0601).
RESULTS: Immunoreactivity of the autophagy-associated markers, beclin 1 and LC3, in carcinoma cells increased in 14% and 52% of the patients, respectively, following the exemestane treatment. These increases were statistically significant (beclin 1, p = 0.016, N = 49; LC3, p < 0.0001, N = 33). The status of M30 immunoreactivity decreased (p = 0.008, N = 47) and TUNEL remained unchanged (N = 53). In addition, tumors with pre-treatment stromal beclin 1 immunoreactivity revealed poor clinical and pathological responses compared with those without stromal beclin 1 immunoreactivity (25% vs 67% for clinical response, p = 0.011, N = 51; 0% vs 41% for pathological response, p = 0.0081, N = 49). Tumors with positive pre-treatment stromal beclin 1 had a higher baseline Ki-67 labeling index (both hot spot and overall average) than those without (p = 0.042 and 0.0075, respectively, N = 53). Results of logistic regression analyses revealed that stromal beclin 1 was a predictor for clinical and pathological responses while ER, PR, Ki-67, and stromal LC3 expressions were not.
CONCLUSIONS: Results of our present study demonstrated that beclin 1 and LC3 immunoreactivity increased in carcinoma cells following exemestane treatment and that the status of pre-treatment stromal beclin 1 is associated with higher carcinoma cell proliferation and poor clinical and pathological responses to NAE.
TRIAL REGISTRATION: UMIN C000000345 (2006/03/06).

Rai G, Mishra S, Suman S, Shukla Y
Resveratrol improves the anticancer effects of doxorubicin in vitro and in vivo models: A mechanistic insight.
Phytomedicine. 2016; 23(3):233-42 [PubMed] Related Publications
BACKGROUND: Resveratrol (RSVL), a well known dietary compound and in combination with doxorubicin (DOX) has gained a global importance for cancer prevention. However, mechanism of action by this combination is not well understood till date.
HYPOTHESIS: The synergistic combination of RSVL and DOX might be more effective in anti-cancer activity by modulating the diverse cancer signaling pathways as compared to their alone treatments.
METHODS: The cytotoxicity of alone and combination doses of RSVL and DOX were analyzed by colorimetric MTT(3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) cell proliferation assay. The migration and colony forming abilities were evaluated by wound healing and clonogenic assays. Apoptosis was detected by Annexin V/PI and DAPI stainings. The cell cycle and intracellular reactive oxygen species (ROS) generation were measured by flow cytometry. The differential expression of genes and proteins were measured by qRT-PCR and western blotting analyses. Finally, in-vivo studies were performed in Ehrlich ascitic carcinoma (EAC) mouse model.
RESULTS: The synergistic combination of DOX (IC20) and RSVL (IC30) was selected based on the combination index values in MCF-7 and MDA-MB-231 cell lines. This combination showed potent growth inhibition with ∼2.5 fold of dose advantage and also significantly decreased the wound healing and clonogenic potential of breast cancer cells. The combination treatment was also found to inhibit the inflammatory response (NF-kB, COX-2), autophagic flux (LC3, Beclin-1), redox regulation (Nrf2) and induces apoptosis (BAX: BCL-2 ratio and Caspase-9) in breast cancer cells. Further, combined dosages of DOX (5 mg/kg b.wt) and RSVL (10 mg/kg b.wt) inhibited tumor volume with increased life span (139%, p value<0.05) in Ehrlich ascitic carcinoma (EAC) cells bearing mice.
CONCLUSION: In brief, our results suggested that resveratrol chemosensitizes doxorubicin in combination, through inhibiting breast cancer cells proliferation and invasion, and inducing apoptosis via suppression of chronic inflammation and autophagy.

Shim BY, Sun DS, Won HS, et al.
Role of autophagy-related protein expression in patients with rectal cancer treated with neoadjuvant chemoradiotherapy.
BMC Cancer. 2016; 16:207 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Autophagy, a cellular degradation process, has complex roles in tumourigenesis and resistance to cancer treatment in humans. The aim of this study was to explore the expression levels of autophagy-related proteins in patients with rectal cancer and evaluate their clinical role in the neoadjuvant chemoradiotherapy setting.
METHODS: All specimens evaluated were obtained from 101 patients with colorectal cancer who had undergone neoadjuvant chemoradiotherapy and curative surgery. The primary outcomes measured were the expression levels of two autophagy-related proteins (microtubule-associated protein 1 light chain 3 beta (LC3β) and beclin-1) by immunohistochemistry and their association with clinicopathological parameters and patient survival.
RESULTS: Among the 101 patients, the frequency of high expression of beclin-1 was 31.7% (32/101) and that of LC3β was 46.5% (47/101). A pathologic complete response was inversely associated with LC3β expression (P = 0.003) and alterations in the expression of autophagy-related proteins (P = 0.046). In the multivariate analysis, however, autophagy-related protein expression did not show prognostic significance for relapse-free survival or overall survival.
CONCLUSIONS: High expression of autophagy-related proteins shows a strong negative association with the efficacy of neoadjuvant chemoradiotherapy in patients with rectal cancer. Autophagy has clear implications as a therapeutic target with which to improve the efficacy of neoadjuvant chemoradiotherapy.

Tan S, Shi H, Ba M, et al.
miR-409-3p sensitizes colon cancer cells to oxaliplatin by inhibiting Beclin-1-mediated autophagy.
Int J Mol Med. 2016; 37(4):1030-8 [PubMed] Related Publications
The chemoresistance of colon cancer cells limits the efficacy of chemotherapy. miR-409-3p has been shown to be downregulated in various types of cancer. In the present study, we examined the role of miR-409-3p in colon cancer as well as the effects of miR‑409-3p on the sensitivity of colon cancer cells to oxaliplatin. The expression of miR-409 was significantly downregulated in the human colon cancer cell lines compared with the normal colon epithelial cells. Importantly, the miR-409-3p expression levels were lower in human colon cancer patient samples than in normal colon tissues. Moreover, we observed a negative correlation between the miR‑409-3p levels and resistance to oxaliplatin: the oxaliplatin-resistant colon cancer cells exhibited significantly downregulated miR‑409-3p levels, but higher autophagic activity than the oxaliplatin-sensitive cells. Using bioinformatics analysis, we predicted that miR‑409-3p miRNA binds to the key autophagy gene encoding Beclin-1. Our findings indicated that the overexpression of miR‑409-3p inhibited Beclin-1 expression and autophagic activity by binding to the 3'-untranslated region of Beclin-1 mRNA. In addition, the overexpression of miR‑409-3p enhanced the chemosensitivity of the oxaliplatin-sensitive and oxaliplatin-resistant colon cancer cells. The restoration of Beclin-1 abrogated these effects of miR‑409-3p. In a xenograft model using nude mice, we examined the effects of miR‑409-3p on tumor growth during chemotherapy. miR‑409-3p overexpression sensitized the tumor to chemotherapy, while inhibiting chemotherapy-induced autophagy in a manner dependent on Beclin-1. The findings of our study suggest that miR-409-3p is capable of enhancing the chemosensitivity of colon cancer cells by inhibiting Beclin-1-mediated autophagy.

Su Z, Wang K, Li R, et al.
Overexpression of RBM5 induces autophagy in human lung adenocarcinoma cells.
World J Surg Oncol. 2016; 14:57 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Dysfunctions in autophagy and apoptosis are closely interacted and play an important role in cancer development. RNA binding motif 5 (RBM5) is a tumor suppressor gene, which inhibits tumor cells' growth and enhances chemosensitivity through inducing apoptosis in our previous studies. In this study, we investigated the relationship between RBM5 overexpression and autophagy in human lung adenocarcinoma cells.
METHODS: Human lung adenocarcinoma cancer (A549) cells were cultured in vitro and were transiently transfected with a RBM5 expressing plasmid (GV287-RBM5) or plasmid with scrambled control sequence. RBM5 expression was determined by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blot. Intracellular LC-3 I/II, Beclin-1, lysosome associated membrane protein-1 (LAMP1), Bcl-2, and NF-κB/p65 protein levels were detected by Western blot. Chemical staining with monodansylcadaverine (MDC) and acridine orange (AO) was applied to detect acidic vesicular organelles (AVOs). The ultrastructure changes were observed under transmission electron microscope (TEM). Then, transplanted tumor models of A549 cells on BALB/c nude mice were established and treated with the recombinant plasmids carried by attenuated Salmonella to induce RBM5 overexpression in tumor tissues. RBM5, LC-3, LAMP1, and Beclin1 expression was determined by immunohistochemistry staining in plasmids-treated A549 xenografts.
RESULTS: Our study demonstrated that overexpression of RBM5 caused an increase in the autophagy-related proteins including LC3-I, LC3-II, LC3-II/LC3-I ratio, Beclin1, and LAMP1 in A549 cells. A large number of autophagosomes with double-membrane structure and AVOs were detected in the cytoplasm of A549 cells transfected with GV287-RBM5 at 24 h. We observed that the protein level of NF-κB/P65 was increased and the protein level of Bcl-2 decreased by RBM5 overexpression. Furthermore, treatment with an autophagy inhibitor, 3-MA, enhanced RBM5-induced cell death and chemosensitivity in A549 cells. Furthermore, we successfully established the lung adenocarcinoma animal model using A549 cells. Overexpression of RBM5 enhanced the LC-3, LAMP1, and Beclin1 expression in the A549 xenografts.
CONCLUSIONS: Our findings showed for the first time that RBM5 overexpression induced autophagy in human lung adenocarcinoma cells, which might be driven by upregulation of Beclin1, NF-κB/P65, and downregulation of Bcl-2. RBM5-enhanced autophagy acts in a cytoprotective way and inhibition of autophagy may improve the anti-tumor efficacy of RBM5 in lung cancer.

Qian HR, Yang Y
Functional role of autophagy in gastric cancer.
Oncotarget. 2016; 7(14):17641-51 [PubMed] Free Access to Full Article Related Publications
Autophagy is a highly regulated catabolic pathway responsible for the degradation of long-lived proteins and damaged intracellular organelles. Perturbations in autophagy are found in gastric cancer. In host gastric cells, autophagy can be induced by Helicobacter pylori (or H. pylori) infection, which is associated with the oncogenesis of gastric cancer. In gastric cancer cells, autophagy has both pro-survival and pro-death functions in determining cell fate. Besides, autophagy modulates gastric cancer metastasis by affecting a wide range of pathological events, including extracellular matrix (ECM) degradation, epithelial-to-mesenchymal transition (EMT), tumor angiogenesis, and tumor microenvironment. In addition, some of the autophagy-related proteins, such as Beclin 1, microtubule-associated protein 1 light chain 3 (MAP1-LC3), and p62/sequestosome 1 (SQSTM1) have certain prognostic values for gastric cancer. In this article, we review the recent studies regarding the functional role of autophagy in gastric cancer.

Zhou Y, Wu PW, Yuan XW, et al.
Interleukin-17A inhibits cell autophagy under starvation and promotes cell migration via TAB2/TAB3-p38 mitogen-activated protein kinase pathways in hepatocellular carcinoma.
Eur Rev Med Pharmacol Sci. 2016; 20(2):250-63 [PubMed] Related Publications
OBJECTIVE: Hepatocellular carcinoma (HCC) is characterized by progressive development and poor prognosis against a background of chronic inflammation. Interleukin (IL)-17A is an important proinflammatory cytokine that contributes to inflammatory pathology and tumor microenvironment. Research on autophagy has increasingly focused on its role in inflammation. Thus, we investigated the effect of IL-17A on the progression of HCC through the autophagic pathway.
MATERIALS AND METHODS: The expression and prognostic values of IL-17A and autophagic gene Beclin-1 were determined using immunohistochemistry in 83 HCC patients after resection. The effects and underlying molecular mechanisms of IL-17A on human HCC were explored in vitro using recombinant human IL-17A.
RESULTS: High expression of IL-17A and low expression of Beclin-1 were associated with worse TNM stage in HCC patients. And the level of autophagy was lower in tumor tissues compared with tumor-adjacent tissues. In vitro, recombinant human IL-17A inhibited starvation-induced autophagy and maintained cell viability through activating TAK1-binding protein 2 (TAB2 and TAK1-binding protein 3 (TAB3)-inducing p38 mitogen-activated protein kinase (MAPK) in Huh7 and HepG2 HCC cells. IL-17A promoted migration of HCC cells through the TAB2/p38 MAPK and TAB3/p38 MAPK pathways.
CONCLUSIONS: IL-17A promotes migration of HCC cells and prevents autophagic cell death from starvation by activating TAB2/p38 MAPK and TAB3/p38 MAPK.

Chen K, Shi W
Autophagy regulates resistance of non-small cell lung cancer cells to paclitaxel.
Tumour Biol. 2016; 37(8):10539-44 [PubMed] Related Publications
Paclitaxel is a chemotherapeutic drug that is effective for treating non-small cell lung cancer (NSCLC). However, some NSCLCs are not sensitive to paclitaxel treatment with undetermined underlying molecular mechanisms. In this study, we found that paclitaxel dose-dependently activated Beclin-1 in 2 NSCLC cell lines, A549 and Calu-3. Inhibition of autophagy significantly increased the paclitaxel-induced NSCLC cell death in a cell counting kit-8 (CCK-8) assay. Moreover, microRNA (miR)-216b levels were significantly downregulated in paclitaxel-treated NSCLC cells. Bioinformatics study showed that miR-216b targeted the 3'-UTR of Beclin-1 mRNA to inhibit its translation, which was confirmed by luciferase reporter assay. Together, these data suggest that paclitaxel may decrease miR-216b levels in NSCLC cells, which subsequently upregulates Beclin-1 to increase NSCLC cell autophagy to antagonize paclitaxel-induced cell death. Strategies that increase miR-216b levels or inhibit cell autophagy may improve the outcome of paclitaxel treatment in NSCLC therapy.

Xu YZ, Li YH, Lu WJ, et al.
YL4073 is a potent autophagy-stimulating antitumor agent in an in vivo model of Lewis lung carcinoma.
Oncol Rep. 2016; 35(4):2081-8 [PubMed] Related Publications
Cancer cells activate autophagy in response to anticancer therapies. Autophagy induction is a promising therapeutic approach to treat cancer. In a previous study, YL4073 inhibited the growth of liver cancer and induced liver cancer cell apoptosis. Here, we demonstrated the anticancer activity and specific mechanisms of YL4073 in Lewis lung carcinoma LL/2 cells. Our results show that YL4073-induced autophagy was followed by apoptotic cell death. The anticancer and autophagy stimulating efficacy was confirmed by several factors, including the appearance of autophagic vacuoles, formation of acidic vesicular organelles, recruitment of microtubule-associated protein 1 light chain 3 II (LC3-II) to the autophagosomes, conversion and cleavage of LC3-I to LC3-II, upregulation of Beclin 1 expression, and formation of the Atg12-Atg5 conjugate in LL/2 cells after YL4073 treatment for 24 or 48 h. Furthermore, P53 activation and p-histone H3 phosphorylation occurred after cell exposure to YL4073 for 48 h, suggesting that cell apoptosis had occurred. Pharmacological inhibition of autophagy using 3-methyladenine increased cell apoptosis. Molecular level studies revealed that YL4073 inhibited survival signalling by blocking the activation of Akt and mTOR phosphorylation and reduced the expression of p-mTOR downstream targets for phosphorylation, including p70S6K, p-TSC, p-MAPK, and p-AMPK. This suggests that the Akt/mTOR/p70S6K and TSC/MAPK/AMPK pathways are involved in the effects of YL4073 treatment in LL/2 cells. In addition, YL4073 significantly inhibited LL/2 tumor growth and induced apoptosis in vivo. These data suggest that YL4073 has a significant anticancer effect, with a pathway-specific mechanism of autophagy both in vitro and in vivo.

Koo JS, Kim JW, Yoon JS
Expression of Autophagy and Reactive Oxygen Species-Related Proteins in Lacrimal Gland Adenoid Cystic Carcinoma.
Yonsei Med J. 2016; 57(2):482-9 [PubMed] Free Access to Full Article Related Publications
PURPOSE: To investigate the difference of expression of autophagy and reactive oxygen species (ROS) related proteins in adenoid cystic carcinoma (ACC) of lacrimal gland in comparison with ACC of salivary gland.
MATERIALS AND METHODS: Formalin-fixed, paraffin-embedded tissue samples from patients pathologically diagnosed as lacrimal gland ACC (n=11) and salivary gland ACC (n=64) were used. Immunochemistry was used to measure expression of autophagy related proteins [beclin-1, light chain (LC) 3A, LC3B, p62, and BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3)] and ROS related proteins [catalase, thioredoxinreductase, glutathione S-transferasepi (GSTpi), thioredoxin interacting protein, and manganese superoxide dismutase (MnSOD)]. The prognostic factors related to disease-free and overall survival (OS) in lacrimal gland ACC by log-rank tests, were determined.
RESULTS: GSTpi in stromal cells was more highly expressed in lacrimal gland ACC (p=0.006), however, MnSOD in epithelial cells was expressed more in salivary gland ACC (p=0.046). LC3B positivity and BNIP3 positivity in epithelial component were associated with shorter disease-free survival (both p=0.002), and LC3A positivity in stromal component was the factor related to shorter OS (p=0.005).
CONCLUSION: This is the first study to demonstrate the expression of autophagy and ROS related proteins in lacrimal gland ACC in comparison with the salivary gland ACC, which would provide a basis for further study of autophagy and ROS mechanism as novel therapeutic targets in lacrimal gland ACC.

Goulielmaki M, Koustas E, Moysidou E, et al.
BRAF associated autophagy exploitation: BRAF and autophagy inhibitors synergise to efficiently overcome resistance of BRAF mutant colorectal cancer cells.
Oncotarget. 2016; 7(8):9188-221 [PubMed] Free Access to Full Article Related Publications
Autophagy is the basic catabolic mechanism that involves cell degradation of unnecessary or dysfunctional cellular components. Autophagy has a controversial role in cancer--both in protecting against tumor progression by isolation of damaged organelles, or by potentially contributing to cancer growth. The impact of autophagy in RAS induced transformation still remains to be further analyzed based on the differential effect of RAS isoforms and tumor cell context. In the present study, the effect of KRAS/BRAF/PIK3CA oncogenic pathways on the autophagic cell properties and on main components of the autophagic machinery like p62 (SQSTM1), Beclin-1 (BECN1) and MAP1LC3 (LC3) in colon cancer cells was investigated. This study provides evidence that BRAF oncogene induces the expression of key autophagic markers, like LC3 and BECN1 in colorectal tumor cells. Herein, PI3K/AKT/MTOR inhibitors induce autophagic tumor properties, whereas RAF/MEK/ERK signalling inhibitors reduce expression of autophagic markers. Based on the ineffectiveness of BRAFV600E inhibitors in BRAFV600E bearing colorectal tumors, the BRAF related autophagic properties in colorectal cancer cells are further exploited, by novel combinatorial anti-cancer protocols. Strong evidence is provided here that pre-treatment of autophagy inhibitor 3-MA followed by its combination with BRAFV600E targeting drug PLX4720 can synergistically sensitize resistant colorectal tumors. Notably, colorectal cancer cells are very sensitive to mono-treatments of another autophagy inhibitor, Bafilomycin A1. The findings of this study are expected to provide novel efficient protocols for treatment of otherwise resistant colorectal tumors bearing BRAFV600E, by exploiting the autophagic properties induced by BRAF oncogene.

Yu X, Li R, Shi W, et al.
Silencing of MicroRNA-21 confers the sensitivity to tamoxifen and fulvestrant by enhancing autophagic cell death through inhibition of the PI3K-AKT-mTOR pathway in breast cancer cells.
Biomed Pharmacother. 2016; 77:37-44 [PubMed] Related Publications
Tamoxifen (TAM) and fulvestrant (FUL) represent the major adjuvant therapy to estrogen receptor-alpha positive (ER(+)) breast cancer patients. However, endocrine resistance to TAM and FUL is a great impediment for successful treatment. We hypothesized that miR-21 might alter the sensitivity of breast cancer cells to TAM or FUL by regulating cell autophagy. Using the ER(+) breast cancer cells, we knockdown miR-21.by transfection with miR-21 inhibitor, then the cells were exposed to TAM or FUL and the percentages of apoptosis and autophagy were determined. Knockdown of miR-21 significantly increased the TAM or FUL-induced apoptosis in ER(+) breast cancer cells. Further, silencing of miR-21 in MCF-7 cells enhanced cell autophagy at both basal and TAM or FUL-induced level. The increase of autophagy in miR-21-knockdown MCF-7 cells was also indicated by increase of beclin-1, LC3-II and increased GFP-LC3 dots. Importantly, knockdown of miR-21 contributed to autophagic cell death, which is responsible for part of TAM induced cell death in miR-21 inhibitor-transfected cells. Further analysis suggested that miR-21 inhibitor enhance autophagic cell death through inhibition of PI3K-AKT-mTOR pathway. MiR-21 coordinated the function of autophagy and apoptosis by targeting Phosphatase and tensin homolog (PTEN) through inhibition of PI3K-AKT-mTOR pathway. In conclusion, silencing of miR-21 increased the sensitivity of ER(+) breast cancer cells to TAM or FUL by increasing autophagic cell death. Targeting autophagy-related miRNAs is a potential strategy for overcoming endocrine resistance to TAM and FUL.

Li P, Guo Y, Bledsoe G, et al.
Kallistatin induces breast cancer cell apoptosis and autophagy by modulating Wnt signaling and microRNA synthesis.
Exp Cell Res. 2016; 340(2):305-14 [PubMed] Free Access to Full Article Related Publications
Kallistatin is an endogenous protein that regulates differential signaling pathways and biological functions. Our previous studies showed that kallistatin gene therapy inhibited angiogenesis, tumor growth and metastasis in mice, and kallistatin protein suppressed Wnt-mediated growth, migration and invasion by blocking Wnt/β-catenin signaling pathway in breast cancer cells. In this study, we show that kallistatin reduced cell viability, and increased apoptotic cell death and caspase-3 activity in MDA-MB-231 breast cancer cells. Kallistatin also induced cancer cell autophagy, as evidenced by increased LC3B levels and elevated Atg5 and Beclin-1 expression; however, co-administration of Wnt or PPARγ antagonist GW9662 abolished these effects. Moreover, kallistatin via its heparin-binding site antagonized Wnt3a-induced cancer cell proliferation and increased PPARγ expression. Kallistatin inhibited oncogenic miR-21 synthesis associated with reduced Akt phosphorylation and Bcl-2 synthesis, but increased BAX expression. Kallistatin via PKC-ERK activation reduced miR-203 levels, leading to increased expression of suppressor of cytokine signaling 3 (SOCS3), a tumor suppressor. Conversely, kallistatin stimulated expression of the tumorigenic suppressors miR-34a and p53. Kallistatin's active site is essential for suppressing miR-21 and miR-203, and stimulating miR-34a and SOCS3 expression. This is the first study to demonstrate that kallistatin's heparin-binding site is essential for inhibiting Wnt-mediated effects, and its active site plays a key role in regulating miR-21, miR-203, miR-34a and SOCS3 synthesis in breast cancer cells. These findings reveal novel mechanisms of kallistatin in inducing apoptosis and autophagy in breast cancer cells, thus inhibiting tumor progression by regulation of Wnt/PPARγ signaling, as well as miR-21, miR-203 and miR-34a synthesis.

Huang K, Cui M, Ye F, et al.
Global profiling of the signaling network of papillary thyroid carcinoma.
Life Sci. 2016; 147:9-14 [PubMed] Related Publications
AIMS: Thyroid carcinoma is one of the most fast rising cancer diagnoses in the US. Papillary thyroid carcinoma (PTC) comprises 80% of thyroid carcinoma. The goal of our study is to identify regulatory proteins and signaling pathways altered in PTC.
MAIN METHODS: Protein Pathway Array (PPA) was applied to screen 65 signaling proteins and phosphoproteins in 27 pairs of PTC and surrounding benign tissues. Ingenuity Pathway Analysis (IPA) was applied to analyze the signaling pathway.
KEY FINDINGS: 11 were differentially expressed between tumors and surrounding tissues, 8 of which were up-regulated (cytokeratin 18, Stat 1, HMG-1, p-p70 S6 kinase, Raf-B, glutamine synthetase, p-PKC δ, and HDAC1), while 3 of which were down-regulated (cytokeratin 5, BECN1, and p-ERK). Further study showed that two proteins (p-p70 S6 kinase and cytokeratin 18) were associated with lymph node metastasis. The top 10 canonical pathways in PTC were identified to be involved in PTC.
SIGNIFICANCE: Taken together, there is a broad array of dysregulation of signaling proteins in PTC, suggesting a heterogeneous group of diseases.

Fader CM, Salassa BN, Grosso RA, et al.
Hemin induces mitophagy in a leukemic erythroblast cell line.
Biol Cell. 2016; 108(4):77-95 [PubMed] Related Publications
BACKGROUND INFORMATION: In eukaryotic cells, autophagy is considered a lysosomal catabolic process which participates in the degradation of intracellular components in a vacuolar structure termed autolysosome. This pathway plays a significant role in the erythropoiesis process, contributing to the clearance of some organelles (such as mitochondria) that are not necessary in the mature red blood cells. Nevertheless, the role of autophagy in erythrocyte maturation has not been fully established.
RESULTS: Here, we have demonstrated that hemin (a physiological erythroid maturation stimulator) is able to induce the expression of critical autophagic genes (i.e., Map1a1b (LC3), Beclin-1 gen, Atg5) in an erythroleukemia cell type. We have also shown that hemin increased the size of autophagic vacuoles which were labelled with LC3 and the degradative lysosomal marker dye quenched-bovine serum albumin. In addition, we have determined by Western blot a rise in the lipidated form of the autophagic protein LC3 (i.e., LC3-II) upon hemin treatment. Moreover, we provide evidence that hemin induces mitochondrial membrane depolarisation and that mitochondria sequestration by autophagy requires the active form of the NIX protein.
CONCLUSIONS: We have found that the physiological erythroid maturation stimulator hemin is able to induce mitophagy in K562 cells, and that the autophagy adaptor NIX is necessary for mitophagy progression. K562 cells have been used as a relevant model to determine the possible therapeutic role of new differentiating compounds.
SIGNIFICANCE: It has been proposed that autophagy induction is a feasible new therapeutic key in fighting cancer. Our results suggest that hemin is favoring erythroid maturation by inducing an autophagic response in K562 cells, being a possible therapeutic candidate that may help in the chronic myelogenous leukemia (CML) treatment.

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