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Circular RNA is a newly discovered member of non‐coding RNA (ncRNA) and regulates the target gene by acting as a micro‐RNA sponge. It plays vital roles in various diseases. However, the functions of circular RNA in non‐small cell lung cancer (NSCLC) remain still unclear. Our data showed that circ‐WHSC1 was highly expressed in NSCLC cells and tissues. Both in vitro and in vivo experiments showed that circ‐WHSC1 promoted NSCLC proliferation. circ‐WHSC1 also promoted the migration and invasion of lung cancer cells. Through bioinformatic analysis and functional experiments, we showed that circ‐WHSC1 could act as a sponge for micro‐RNA‐7 (miR‐7) and regulate the expression of TAB2 (TGF‐beta activated kinase one binding protein two). Inhibition of the circ‐WHSC1/miR‐7/TAB2 pathway could effectively attenuate lung cancer progression. In summary, this study confirmed the existence and oncogenic function of circ‐WHSC1 in NSCLC. The research suggests that the circ‐WHSC1/miR‐7/TAB2 axis might be a potential target for NSCLC therapy.

Circular RNA (circRNA) is a type of noncoding RNA that can interact with miRNAs to regulate gene expression. However, little is known concerning circRNA, which is crucial in the pathogenesis of lung cancer. To date, limited studies have explored the role of circ_0044516 in lung cancer progression. Recently, we observed that circ_0044516 expression levels were obviously elevated in lung cancer tissues and cells. A549 and SPCA1 cells were transfected with circ_0044516 siRNA. We observed that knockdown of circ_0044516 dramatically repressed cell proliferation, increased cell apoptosis, and repressed the cell cycle. Moreover, A549 and SPCA1 cell migration and invasion abilities were greatly repressed by circ_0044516 siRNA. Due to accumulating evidence demonstrating the vital role of cancer stem cells, their mechanism of involvement has drawn increasing attention in tumor progression and metastasis research. We also found that cancer stem cell properties were restrained by silencing circ_0044516 in A549 and SPC-A1 cells. Moreover, in vivo xenograft experiments showed that circ_0044516 downregulation reduced tumor growth. Mechanistically, in lung cancer and using bioinformatics, we demonstrated that circ_0044516 sponges miR-136 targeting MAT2A. Furthermore, rescue assays were carried out to identify that circ_0044516 modulates cell proliferation, invasion, and stemness by regulating miR-136 and MAT2A in lung cancer. In summary, our study revealed that the circ_0044516/miR-136/MAT2A axis is involved in lung cancer progression. Our findings may provide novel targets for diagnosis and therapeutic intervention in lung cancer patients.

Scorpiothyrsus erythrotrichus belongs to Melastomataceae. Here, we present its complete plastome. To our knowledge, this is the first reported complete chloroplast genome of S. erythrotrichus. The complete plastome of S. erythrotrichus is 160,731 bp in length with a typical quadripartite structure, consisting of four regions: large single-copy (LSC) region (85,483 bp), small single-copy (SSC) region (17,007 bp), and two inverted repeat regions (IRs, 26,780 bp). It contains 128 genes (79 coding genes, four rRNAs, and 30 tRNAs). The overall GC content is 36.9% and in the LSC, SSC, and IR regions are 34.70%, 30.40%, and 42.50%, respectively. Our study contributes to the molecular phylogenetic studies of Scorpiothyrsus and Melastomataceae.

Callicarpa nudiflora Vahl is a medicinal plant occurring in Guangdong, Guangxi, Hainan provinces of China. Here, we report and characterize the complete plastid genome sequence of C. nudiflora in an effort to provide genomic resources useful for promoting its conservation. The complete plastome is 154,080 bp in length and contains the typical structure and gene content of angiosperm plastome, including two inverted repeat (IR) regions of 25,657 bp, a large single-copy (LSC) region of 84,949 bp, and a small single-copy (SSC) region of 17,817 bp. There are 113 genes annotated, including 79 unique protein-coding genes, 4 unique ribosomal RNA genes, and 30 transfer RNA genes. To investigate the evolution status of C. nudiflora, as well as Verbenaceae, we constructed a phylogenetic tree with C. nudiflora and other 11 species based on their complete chloroplast genomes. According to the phylogenetic topologies, C. nudiflora was closely related to Lancea hirstua.

OBJECTIVE The expression levels of histone deacetylase 2 (HDAC2), eukaryotic initiation factor 5 (eIF5), and eukaryotic initiation factor 6 (eIF6), and relationship between HDAC2 and eIF5 or eIF6 in lung cancer tissues were investigated, in order to charify the relationship between HDAC2 and the prognosis of lung cancer patients and its influence on the expression of eIF5 and eIF6. METHODS The expression of HDAC2, eIF5, and eIF6 in lung cancer tissues was detected by quantitative reverse transcription polymerase chain reaction. The expression correlation between HDAC2 and eIF5 or eIF6 was tested using a t test. The correlation between HDAC2 and eIF5 or eIF6 was analyzed using the TCGA database. The identified cells were constructed with small interfering siRNA and HDAC2 overexpression plasmid. The proliferation and migration ability of the identified cells was investigated by CCK8 and Transwell assays, respectively. RESULTS HDAC2, eIF5, and eIF6 were overexpressed in lung cancer tissues, and HDAC2 expression level was negatively correlated with the prognosis of lung cancer patients. HDAC2 expression level was positively correlated with eIF5 and eIF6 expression levels. HDAC2 could regulate the expression of eIF5 and eIF6. The regulation of proliferation and invasion of lung cancer cells by HDAC2 depended on eIF5 and eIF6. CONCLUSION HDAC2, eIF5, and eIF6 were closely related with lung cancer tumorigenesis, which might be potential biological markers and therapeutic targets for lung cancer.

Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (HMGR) inhibitors decreasing serum cholesterol and have shown promise in cancer prevention. In this study, we demonstrated the oncogenic role of HMGR in colorectal cancer (CRC) by disclosing increased HMGR activity in CRC patients and its enhancement of anti-apoptosis and stemness. Our previous studies showed that statins containing carboxylic acid chains possessed activity against histone deacetylases (HDACs), and strengthened their anti-HDAC activity through designing HMGR-HDAC dual inhibitors, JMF compounds. These compounds exerted anti-cancer effect in CRC cells as well as in AOM-DSS and ApcMin/+ CRC mouse models. JMF mostly regulated the genes related to apoptosis and inflammation through genome-wide ChIP-on-chip analysis, and Ingenuity Pathways Analysis (IPA) predicted their respective regulation by NR3C1 and NF-κB. Furthermore, JMF inhibited metastasis, angiogenesis and cancer stemness, and potentiated the effect of oxaliplatin in CRC mouse models. Dual HMGR-HDAC inhibitor could be a potential treatment for CRC.

Maspin is a tumor suppressor that stimulates apoptosis and inhibits metastasis in various cancer types, including hepatocellular carcinoma (HCC). Our previous study has demonstrated that HBx induced microRNA-7, 103, 107, and 21 expressions to suppress maspin expression, leading to metastasis, chemoresistance, and poor prognosis in HCC patients. However, it remains unclear how HBx elicits these microRNA expressions. HBx has been known to induce aberrant activation and nuclear translocation of inhibitor-κB kinase-α (IKKα) to promote HCC progression. In this study, our data further revealed that nuclear IKKα expression was inversely correlated with maspin expression in HBV-associated patients. Nuclear IKKα but not IKKβ reduced maspin protein and mRNA expression, and inhibition of IKKα reverses HBx-mediated maspin downregulation and chemoresistance. In response to HBx overexpression, nuclear IKKα was further demonstrated to induce the gene expressions of microRNA-7, -103, -107, and -21 by directly targeting their promoters, thereby leading to maspin downregulation. These findings indicated nuclear IKKα as a critical regulator for HBx-mediated microRNA induction and maspin suppression, and suggest IKKα as a promising target to improve the therapeutic outcome of HCC patients.

Hepatocellular carcinoma (HCC) is among the most common and lethal human cancers worldwide. Despite curative resection, high recurrence of HCC remains a big threat, leading to poor patient outcomes. Hepatitis B virus (HBV) pre-S mutants, which harbor deletions over pre-S1 and pre-S2 gene segments of large surface proteins, have been implicated in HCC recurrence. Therefore, a reliable approach for detection of pre-S mutants is urgently needed for predicting HCC recurrence to improve patient survival. In this study, we used a next-generation sequencing (NGS)-based platform for quantitative detection of pre-S mutants in the plasma of HBV-related HCC patients and evaluated their prognostic values in HCC recurrence. We demonstrated that the presence of deletions spanning the pre-S2 gene segment and the high percentage of pre-S2 plus pre-S1 + pre-S2 deletions, either alone or in combination, was significantly and independently associated with poor recurrence-free survival and had greater prognostic performance than other clinicopathological and viral factors in predicting HCC recurrence. Our data suggest that the NGS-based quantitative detection of pre-S mutants in plasma represents a promising approach for identifying patients at high risk for HBV-related HCC recurrence after surgical resection in a noninvasive manner.

Poor prognosis of hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) involves HBV X protein (HBx)-induced tumor progression. HBx also contributes to chemo-resistance via inducing the expressions of anti-apoptosis and multiple drug resistance genes. However, the impact of HBx expression on the therapeutic efficacy of various receptor tyrosine kinase inhibitors remains unknown. In this study, our data showed that HBx overexpression did not alter the cellular sensitivity of HCC cell lines to sorafenib but unexpectedly enhanced the cell death induced by EGFR family inhibitors, including gefitinib, erlotinib, and lapatinib due to ErbB3 up-regulation. Mechanistically, HBx transcriptionally up-regulates ErbB3 expression in a NF-κB dependent manner. In addition, HBx also physically interacts with ErbB2 and ErbB3 proteins and enhances the formation of ErbB2/ErbB3 heterodimeric complex. The cell viability of HBx-overexpressing cells was decreased by silencing ErbB3 expression, further revealing the pivotal role of ErbB3 in HBx-mediated cell survival. Our data suggest that HBx shifts the oncogenic addiction of HCC cells to ErbB2/ErbB3 signaling pathway via inducing ErbB3 expression and thereby enhances their sensitivity to EGFR/ErbB2 inhibitors.

Maspin suppresses tumor progression by promoting cell adhesion and apoptosis and by inhibiting cell motility. However, its role in tumorigenesis of hepatocellular carcinoma (HCC) remains unclear. The gene regulation of maspin and its relationship with HCC patient prognosis were investigated in this study. Maspin expression was specifically reduced in HBV-associated patients and correlated with their poor prognosis. Maspin downregulation in HCC cells was induced by HBx to promote their motility and resistance to anoikis and chemotherapy. HBx-dependent induction of microRNA-7, -107, and -21 was further demonstrated to directly target maspin mRNA, leading to its protein downregulation. Higher expressions of these microRNAs also correlated with maspin downregulation in HBV-associated patients, and were associated with their poor overall survival. These data not only provided new insights into the molecular mechanisms of maspin deficiency by HBx, but also indicated that downregulation of maspin by microRNAs confers HBx-mediated aggressiveness and chemoresistance in HCC.

High-performance copper-coated tungsten composite powders were successfully prepared using electroless plating at an appropriate pH in the plating bath. The effect of pH value in the plating bath on the microstructure and purity of the coated Cu layer was studied systematically. With the increase of pH in the bath, the surface roughness, particle size and average grain size of coated Cu increased, and the particle shape gradually changed from round into square block. At pH 12–12.5, coated Cu was highly pure with very little oxygen content (less than 0.09 wt.%). The promotion effect of the increased pH on both main electroless plating reaction and side reactions causes the changes of surface morphology, average grain size of Cu and the oxygen content in the composite powders.

Object: To detect expression of hypoxia inducible factor-1α (HIF-1α) and lysyl oxidase (LOX) in non-small cell lung cancer (NSCLC) and explore their roles in prognosis. Methods: The mRNA levels of HIF-1α and LOX were investigated by real-time reverse-transcriptase polymerase chain reaction in 40 cases of tumour and paired normal tissues. In addition, protein expression of HIF-1α and LOX was examined by immunohistochemistry in 82 cases of tumour and 45 paired normal tissues. The relationship between HIF-1α or LOX and clinicopathologic characteristics, as well as the correlation between HIF-1α and LOX, were also examined. Kaplan-Meier survival curves and the log-rank test were used to analyze progression-free survival. Results: HIF-1α or LOX mRNA levels in tumor tissues was significantly higher than those in paired normal tissues ( p

Lapatinib, a dual epidermal growth factor receptor (EGFR)/human epidermal growth factor receptor 2 (HER2) kinase inhibitor, showed clinical benefits in advanced HER2-positive breast cancer patients. Because some triple-negative breast cancers (TNBCs) frequently overexpress EGFR, the antitumor activity of lapatinib in such diseases was also tested. However, the results showed a worse event-free survival rate. It remains unknown whether and how lapatinib elicits the aggressiveness of such cancer cells. In this study, our results demonstrated that lapatinib facilitated axillary and lung metastases of triple-negative MDA-MB-231 breast cancer cells without affecting their viability, leading to worse survival in orthotopic xenograft mice. The lapatinib-increased motility was attributed by the elevation of EGFR through the downregulation of microRNA-7 and by the subsequent overexpression of cyclooxygenase-2 (COX-2). Strikingly, independent of its kinase activity, the elevated EGFR at least partly stabilized COX-2 expression by enhancing the binding of HuR to COX-2 mRNA. Our results suggest that lapatinib may increase the migration and invasion of MDA-MB-231 cells by upregulating EGFR and COX-2 through the downregulation of microRNA-7, providing a potential explanation for the worse clinical outcome of TNBC patients who receive lapatinib-based treatment. These findings also shed new light on the molecular mechanism of COX-2 mRNA stabilization by EGFR in a kinase-independent manner.

Purpose: The aim of this study was to investigate whether fisetin is a potential radiosensitizer for human colorectal cancer cells, which are relatively resistant to radiotherapy. Methods and Materials: Cell survival was examined by clonogenic survival assay, and DNA fragmentation was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. The effects of treatments on cell cycle distribution and apoptosis were examined by flow cytometry. Western blot analysis was performed to ascertain the protein levels of {gamma}-H2AX, phospho-Chk2, active caspase-3, PARP cleavage, phospho-p38, phospho-AKT, and phospho-ERK1/2. Results: Fisetin pretreatment enhanced the radiosensitivity of p53-mutant HT-29 human colorectal cancer cells but not human keratocyte HaCaT cells; it also prolonged radiation-induced G{sub 2}/M arrest, enhanced radiation-induced cell growth arrest in HT-29 cells, and suppressed radiation-induced phospho-H2AX (Ser-139) and phospho-Chk2 (Thr-68) in p53-mutant HT-29 cells. Pretreatment with fisetin enhanced radiation-induced caspase-dependent apoptosis in HT-29 cells. Fisetin pretreatment augmented radiation-induced phosphorylation of p38 mitogen-activated protein kinase, which is involved in caspase-mediated apoptosis, and SB202190 significantly reduced apoptosis and radiosensitivity in fisetin-pretreated HT-29 cells. By contrast, both phospho-AKT and phospho-ERK1/2, which are involved in cell proliferation and antiapoptotic pathways, were suppressed after irradiation combined with fisetin pretreatment. Conclusions: To our knowledge, this study ismore » the first to provide evidence that fisetin exerts a radiosensitizing effect in p53-mutant HT-29 cells. Fisetin could potentially be developed as a novel radiosensitizer against radioresistant human cancer cells.« less

Purpose Radiotherapy is one of the best choices for cancer treatment. However, various tumor cells exhibit resistance to irradiation-induced apoptosis. The development of new strategies to trigger cancer cell death besides apoptosis is necessary. This study investigated the role of securin in radiation-induced apoptosis and senescence in human cancer cells. Methods and Materials Cell survival was determined using clonogenic assays. Western blot analysis was used to analyze levels of securin, caspase-3, PARP, p53, p21, Rb, γ-H2AX, and phospho-Chk2. Senescent cells were analyzed using a β-galactosidase staining assay. A securin-expressed vector (pcDNA-securin) was stably transfected into securin-null HCT116 cells. Securin gene knockdown was performed by s mall interfering RNA and small hairpin RNA in HCT116 and MDA-MB-231 cells, respectively. Results Radiation was found to induce apoptosis in securin wild type HCT116 cells but induced senescence in securin-null cells. Restoration of securin reduced senescence and increased cell survival in securin-null HCT116 cells after irradiation. Radiation-induced γ-H2AX and Chk2 phosphorylation were induced transiently in securin-wild-type cells but exhibited sustained activation in securin-null cells. Securin gene knockdown switches irradiation-induced apoptosis to senescence in both HCT116 p53-null and MDA-MB-231 cells. Conclusions Our results demonstrated that the level of securin expression plays a determining role in the radiosensitivity and fate of cells. Depletion of securin impairs DNA repair after irradiation, increasing DNA damage and promoting senescence in the residual surviving cells regardless of functional p53 expression. The knockdown of securin may contribute to a novel radiotherapy protocol for the treatment of human cancer cells that are resistant to irradiation.

For a preliminary study of the role of beta-catenin/Tcf signaling in squamous differentiation of airway (tracheobronchial) epithelial cells, a stable mutant of beta-catenin was transfected into primarily cultured porcine airway epithelial cells. Western blotting revealed that exogenous protein was observed in large quantity in cytoplasm and nucleus. When co-transfected with Tcf luciferase reporter plasmids, beta-catenin mutant increased the reporter's transcriptional activities. However, mRNA expression of a squamous differentiation marker, small proline-rich protein (SPRP), was not elevated, as shown by reverse transcription-polymerase chain reaction. These findings suggest that beta-catenin/Tcf signaling may not be directly involved in the squamous differentiation of porcine airway epithelial cells.

Lapatinib, a dual EGFR/HER2 tyrosine kinase inhibitor, has been shown to improve the survival rate of patients with advanced HER2-positive breast cancers. However, the off-target activity of lapatinib in inducing EGFR expression without tyrosine kinase activity was demonstrated to render HER2-negative breast cancer cells more metastatic, suggesting a limitation to the therapeutic effectiveness of this dual inhibitor in HER2-heterogeneous tumors. Therefore, targeting EGFR expression may be a feasible approach to improve the anticancer efficiency of lapatinib-based therapy. Inhibition of HDAC has been previously reported to epigenetically suppress EGFR protein expression. In this study, however, our data indicated that treatment with HDAC inhibitors trichostatin A (TSA), but not suberoylanilide hydroxamic acid (SAHA) or HDAC siRNA, can attenuate both protein and mRNA expressions of EGFR in lapatinib-treated triple-negative breast cancer cells, suggesting that TSA may suppress EGFR expression independently of HDAC inhibition. Nevertheless, TSA reduced EGFR 3′UTR activity and induced the gene expression of microRNA-7, a known EGFR-targeting microRNA. Furthermore, treatment with microRNA-7 inhibitor attenuated TSA-mediated EGFR suppression. These results suggest that TSA induced microRNA-7 expression to downregulate EGFR expression in an HDAC-independent manner.

Introduction Triple-negative breast cancer (TNBC), a subtype of breast cancer with negative expressions of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2), is frequently diagnosed in younger women and has poor prognosis for disease-free and overall survival. Due to the lack of known oncogenic drivers for TNBC proliferation, clinical benefit from currently available targeted therapies is limited, and new therapeutic strategies are urgently needed. Methods Triple-negative breast cancer cell lines were treated with proteasome inhibitors in combination with lapatinib (a dual epidermal growth factor receptor (EGFR)/HER2 tyrosine kinase inhibitor). Their in vitro and in vivo viability was examined by MTT assay, clonogenic analysis, and orthotopic xenograft mice model. Luciferase reporter gene, immunoblot, and RT-qPCR, immunoprecipitation assays were used to investigate the molecular mechanisms of action. Results Our data showed that nuclear factor (NF)-κB activation was elicited by lapatinib, independent of EGFR/HER2 inhibition, in TNBCs. Lapatinib-induced constitutive activation of NF-κB involved Src family kinase (SFK)-dependent p65 and IκBα phosphorylations, and rendered these cells more vulnerable to NF-κB inhibition by p65 small hairpin RNA. Lapatinib but not other EGFR inhibitors synergized the anti-tumor activity of proteasome inhibitors both in vitro and in vivo. Our results suggest that treatment of TNBCs with lapatinib may enhance their oncogene addiction to NF-κB, and thus augment the anti-tumor activity of proteasome inhibitors. Conclusions These findings suggest that combination therapy of a proteasome inhibitor with lapatinib may benefit TNBC patients.

Hepatitis B virus- (HBV-) associated hepatocellular carcinoma (HCC) is the most common type of liver cancer. However, the underlying mechanism of HCC tumorigenesis is very complicated and HBV-encoded X protein (HBx) has been reported to play the most important role in this process. Activation of downstream signal pathways of epidermal growth factor receptor (EGFR) family is known to mediate HBx-dependent HCC tumor progression. Interestingly, HER2 (also known as ErbB2/Neu/EGFR2) is frequently overexpressed in HBx-expressing HCC patients and is associated with their poor prognosis. However, it remains unclear whether and how HBx regulates HER2 expression. In this study, our data showed that HBx expression increased HER2 protein level via enhancing its mRNA stability. The induction of RNA-binding protein HuR expression by HBx mediated the HER2 mRNA stabilization. Finally, the upregulated HER2 expression promoted the migration ability of HBx-expressing HCC cells. These findings deciphered the molecular mechanism of HBx-mediated HER2 upregulation in HBV-associated HCC.

Background Granular cell tumors (GCT), especially in the esophagus, are rare neoplasms originating from the nervous system. There is still some controversy regarding the diagnosis and treatment of esophageal GCT. Methods We report 14 cases of esophageal GCT diagnosed and treated from January 2004 to March 2013. Their clinical manifestations, endoscopic image, endoscopic ultrasonography (EUS) appearance, pathology, immunohistochemistry, treatment, and prognosis were reviewed. Results The typical images of EUS were hypoechoic, homogenous, and smooth-edged tumors restricted to deep mucosal and submucosal layers. However, there were 2 cases with tumors invading muscular layer. Endoscopic ultrasonography was valuable to assess the tumor size, location, depth of invasion, and nature. According to EUS manifestation, 11 cases with lesions 3 cm or less in diameter without muscular layer invasion underwent endoscopic resection without complication and the other 3 cases underwent surgical resection. A new technique of submucosal tunnel endoscopic resection was performed in 3 submucosal cases with lesions ranging from 2 cm to 3 cm in diameter. All of these cases were benign and histology was necessary for differential diagnosis. Conclusions Endoscopic ultrasonography plays an important guiding role in the diagnosis and treatment of esophageal GCT. Submucosal tunnel endoscopic resection is safe and effective. Further study is needed to determine whether this technique can be expanded into other applications.

Hepatitis B virus (HBV) infection accounts for over a half of cases of hepatocellular carcinoma (HCC), the most frequent malignant tumor of the liver. HBV-encoded X (HBx) plays critical roles in HBV-associated hepatocarcinogenesis. However, it is unclear whether and how HBx regulates the expression of epidermal growth factor receptor (EGFR), an important gene for cell growth. Therefore, the study aimed to investigate the association between HBx and EGFR expression. In this study, we found that HBx upregulates miR-7 expression to target 3′UTR of EGFR mRNA, which in turn results in the reduction of EGFR protein expression in HCC cells. HBx-mediated EGFR suppression renders HCC cells a slow-growth behavior. Deprivation of HBx or miR-7 expression or restoration of EGFR expression can increase the growth rate of HCC cells. Our data showed the miR-7-dependent EGFR suppression by HBx, supporting an inhibitory role of HBx in the cell growth of HCC. These findings not only identify miR-7 as a novel regulatory target of HBx, but also suggest HBx-miR-7-EGFR as a critical signaling in controlling the growth rate of HCC cells.

The outcome of producing apoptotic defects in cancer cells is the primary obstacle that limits the therapeutic efficacy of anticancer agents, and hence the development of novel agents targeting novel non-canonical cell death pathways has become an imperative mission for clinical research. Fisetin (3,3',4',7-tetrahydroxyflavone) is a naturally occurring flavonoid commonly found in fruits and vegetables. In this study, we investigated the potential anticancer effects of fisetin on breast cancer cells. The result showed fisetin induced higher cytotoxicity in human breast cancer MCF-7 than in MDA-MB-231 cells otherwise it did not exert any detectable cytotoxicity in non-tumorigenic MCF-10A cells. We found fisetin can trigger a novel form of atypical apoptosis in caspase-3-deficient MCF-7 cells, which was characterized by several apoptotic features, including plasma membrane rupture, mitochondrial depolarization, activation of caspase-7, -8 and -9, and PARP cleavage; however, neither DNA fragmentation and phosphotidylserine (PS) externalization was observed. Although p53 was also activated by fisetin, the fisetin-induced apoptosis was not rescued by the p53 inhibitor pifithrin-α. In contrast, the fisetin-induced apoptosis was abrogated by pan-caspase inhibitor z-VAD-fmk. Furthermore, inhibition of autophagy by fisetin was shown as additional route to prompt anticancer activity in MCF-7 cells. These data allow us to propose that fisetin appears as a new potential anticancer agent which can be applied to develop a clinical protocol of human breast cancers.

Hepatitis B virus (HBV) X protein (HBx) has been implicated in HBV-associated carcinogenesis through activation of IκB kinase (IKK)/nuclear factor kappa B (NF-κB) signaling pathway. Besides activating NF-κB in the cytoplasm, IKKα was found in the nucleus to regulate gene expression epigenetically in response to various stimuli. However, it is unknown whether nuclear IKKα plays a role in HBx-associated tumor progression. Moreover, the molecular mechanism underlying IKKα nuclear transport also remains to be elucidated. Here, we disclosed HBx as a new inducer of IKKα nuclear transport in hepatoma cells. HBx induced IKKα nuclear transport in an Akt-dependent manner. HBx-activated Akt promoted IKKα nuclear translocation via phosphorylating its threonine-23 (Thr23). In addition, IKKα ubiquitination enhanced by HBx and Akt also contributed to the IKKα accumulation in the nucleus, indicating the involvement of ubiquitination in Akt-increased IKKα nuclear transport in response to HBx. Furthermore, inhibition of IKKα nuclear translocation by mutation of its nuclear localization signal and Thr23 diminished IKKα-dependent cell migration. Taken together, our findings shed light on the molecular mechanism of IKKα nuclear translocation and provide a potential role of nuclear IKKα in HBx-mediated hepatocellular carcinoma (HCC) progression. J. Cell. Physiol. 227: 1446–1454, 2012. © 2011 Wiley Periodicals, Inc.

Network-on-chip (NoC) architectures have been recently proposed as the communication framework for large-scale chips. The design of the routing system for the packet-switched on-chip network is one of the critical issues for the success of NoC architectures, especially when there are faulty components in the network. In this paper, we present a routing technique that uses an embedded tree for mesh networks to achieve high-performance on-chip communication. In this design, the abundant links not belonging to the embedded tree become shortcuts to reduce the distance for packet routing. We show that our routing is deadlock-free and, with appropriate mapping of the tree, equivalent to the well-known XY routing for mesh networks. Furthermore, when there are faulty components in the network, our switch can still successfully deliver packets through tree re-mapping as long as the network is connected. Our design is evaluated by using static analysis and simulation for faulty networks with various network sizes. The results show that our design achieves superior performance without using a routing table in the switch for faulty mesh on-chip networks.

Oxaliplatin, a chemotherapeutic drug, induces DNA double-strand breaks (DSBs) and apoptosis in colorectal cancer cells. It has been shown that gamma-H2AX acts as a marker of DSBs. However, the molecular events associated with oxaliplatin-mediated cell cycle arrest and cell death remain unclear. In this study, we investigated the roles of p53 and gamma-H2AX following oxaliplatin treatment, as they are important effector proteins for apoptosis and DSB repair, respectively. Both phosphorylated-p53 (Ser-15) and gamma-H2AX were up-regulated and accumulated in the nuclei of p53-wild type human colorectal cancer HCT116 cells after exposure to oxaliplatin. Concomitantly, oxaliplatin-induced G2/M arrest was associated with a reduction in both cyclin B1 expression and phosphorylated-CDC2 (Thr-161). Release of G2/M arrest by caffeine was accompanied by a decrease in the levels of p53/p21; however, gamma-H2AX levels were unchanged. Furthermore, inhibition of p53 phosphorylation by pifithrin-alpha was sufficient to reduce the oxaliplatin-induced up-regulation of gamma-H2AX and apoptosis. Oxaliplatin-induced gamma-H2AX via a p53-independent pathway but did not cause caspase-3 activation in p53-null HCT116 cells. Interestingly, no changes were observed in the H2AX gene knockdown with regards to oxaliplatin-induced G2/M arrest in p53-wild type and S phase arrest in p53-null HCT116 cells. Taken together, these data indicate that a molecular pathway involving p53, gamma-H2AX and cell cycle arrest plays a pivotal role in the cellular response to oxaliplatin.

Epidemiological evidence suggests that cigarette smoke induces squamous metaplasia in human tracheobronchial epithelium that can progress to lung squamous carcinoma. But it is not well understood how tracheobronchial epithelial cells transduce the signals that mediate cigarette smoke-induced squamous differentiation or squamous metaplasia. In the present study, we found that in vitro cigarette smoke components notably inhibited glycogen synthase kinase 3 (GSK3) and induced the expression of involucrin, a marker of squamous differentiation. The inactivation of GSK3 by two highly selective inhibitors, lithium and SB216763, also significantly enhanced involucrin expression in cultured porcine tracheobronchial epithelial cells (PTBECs). Moreover, we demonstrated that cigarette smoke components significantly promoted activator protein-1 (AP-1) binding activities to the upstream regulatory region of involucrin gene, and similar results were observed by further studies through using GSK3 inhibitors to imitate the effects of cigarette smoke components. Taken together, we conclude that GSK3 is involved in involucrin expression induced by cigarette smoke in PTBEC probably via negatively regulating AP-1 activity, implying a possible mechanism responsible for squamous differentiation induced by cigarette smoke.

To investigate if glycogen synthase kinase 3 (GSK3) is involved in squamous differentiation of airway (tracheobronchial) epithelial cells, primary pig airway epithelial cells were treated with lithium chloride, a highly selective inhibitor of GSK3. Change in morphology of cells was monitored under microscopy, and expression of beta-catenin, phosphorylated GSK3 and involucrin, a squamous differentiation marker, were dectected by Western blotting, while expression of mRNA of another squamous differentiation marker, small proline-rich protein, was detected by RT-PCR. Further, luciferase reporter assay was used to assess the activation of beta-catenin/Tcf signaling. The results demonstrated that lithium was able to induce a squamous morphology of the cells, and to enhance the expression of involucrin and small proline-rich protein mRNA. Moreover, lithium increased inhibitory phosphorylation of GSK3, augmented nuclear translocation of beta-catenin in a dose- and time-dependent manner. Activation of beta-catenin/Tcf signaling was observed after the elevation of squamous differentiation markers. Taken together, these data suggest that GSK3 is possibly involved in squamous differentiation of pig airway epithelial cells.