Overexpression of CDC2/CyclinB1 in gliomas, and CDC2 depletion inhibits proliferation of human glioma cells in vitro and in vivo

USP39-mediated deubiquitination of Cyclin B1 promotes tumor cell proliferation and glioma progression

BACKGROUND

The elevated Cyclin B1 expression contributes to various tumorigenesis and poor prognosis. Cyclin B1 expression could be regulated by ubiquitination and deubiquitination. However, the mechanism of how Cyclin B1 is deubiquitinated and its roles in human glioma remain unclear.

METHODS

Co-immunoprecipitation and other assays were performed to detect the interacting of Cyclin B1 and USP39. A series of in vitro and in vivo experiments were performed to investigate the effect of USP39 on the tumorigenicity of tumor cells.

RESULTS

USP39 interacts with Cyclin B1 and stabilizes its expression by deubiquitinating Cyclin B1. Notably, USP39 cleaves the K29-linked polyubiquitin chain on Cyclin B1 at Lys242. Additionally, overexpression of Cyclin B1 rescues the arrested cell cycle at G2/M transition and the suppressed proliferation of glioma cells caused by USP39 knockdown in vitro. Furthermore, USP39 promotes the growth of glioma xenograft in subcutaneous and in situ of nude mice. Finally, in human tumor specimens, the expression levels of USP39 and Cyclin B1 are positively relevant.

CONCLUSION

Our data support the evidence that USP39 acts a novel deubiquitinating enzyme of Cyclin B1 and promoted tumor cell proliferation at least in part through Cyclin B1 stabilization, represents a promising therapeutic strategy for tumor patients.

Penalized estimation of a class of single-index varying-coefficient models for integrative genomic analysis

Recent technological advances have made it possible to collect high-dimensional genomic data along with clinical data on a large number of subjects. In the studies of chronic diseases such as cancer, it is of great interest to integrate clinical and genomic data to build a comprehensive understanding of the disease mechanisms. Despite extensive studies on integrative analysis, it remains an ongoing challenge to model the interaction effects between clinical and genomic variables, due to high dimensionality of the data and heterogeneity across data types. In this paper, we propose an integrative approach that models interaction effects using a single-index varying-coefficient model, where the effects of genomic features can be modified by clinical variables. We propose a penalized approach for separate selection of main and interaction effects. Notably, the proposed methods can be applied to right-censored survival outcomes based on a Cox proportional hazards model. We demonstrate the advantages of the proposed methods through extensive simulation studies and provide applications to a motivating cancer genomic study.

Therapeutic potential of parkin as a tumor suppressor via transcriptional control of cyclins in glioblastoma cell and animal models

Parkin (PK) is an E3-ligase harboring tumor suppressor properties that has been associated to various cancer types including glioblastoma (GBM). However, PK is also a transcription factor (TF), the contribution of which to GBM etiology remains to be established.

Methods: The impact of PK on GBM cells proliferation was analyzed by real-time impedance measurement and flow cytometry. Cyclins A and B proteins, promoter activities and mRNA levels were measured by western blot, luciferase assay and quantitative real-time PCR. Protein-protein and protein-promoter interactions were performed by co-immunoprecipitation and by ChIP approaches. The contribution of endogenous PK to tumor progression in vivo was performed by allografts of GL261 GBM cells in wild-type and PK knockout mice.

Results: We show that overexpressed and endogenous PK control GBM cells proliferation by modulating the S and G2/M phases of the cell cycle via the trans-repression of cyclin A and cyclin B genes. We establish that cyclin B is regulated by both E3-ligase and TF PK functions while cyclin A is exclusively regulated by PK TF function. PK invalidation leads to enhanced tumor progression in immunocompetent mice suggesting an impact of PK-dependent tumor environment to tumor development. We show that PK is secreted by neuronal cells and recaptured by tumor cells. Recaptured PK lowered cyclins levels and decreased GBM cells proliferation. Further, PK expression is decreased in human GBM biopsies and its expression is inversely correlated to both cyclins A and B expressions.

Conclusion: Our work demonstrates that PK tumor suppressor function contributes to the control of tumor by its cellular environment. It also shows a key role of PK TF function in GBM development via the control of cyclins in vitro and in vivo. It suggests that therapeutic strategies aimed at controlling PK shuttling to the nucleus may prove useful to treat GBM.

Twenty Years After Glioblastoma Multiforme Diagnosis: A Case of Long-Term Survival

Glioblastoma multiforme (GBM) is an aggressive tumor that has a poor prognosis with a median survival of 15 months with treatment and 3-4 months without treatment. Subsets of patients are found to survive longer than two years, some survivors lived more than 10 years, and rare cases survived 20 years or more with treatment. Better prognosis has been found to be associated with many factors. Some of these factors are related to patients' characteristics, biological factors that impact tumor aggressiveness, and/or factors associated with treatment. However, the exact contribution for extended survival is still not known. Finding the factors that have a strong impact on the long survival is of high importance and can help give hope to better treat glioblastoma cases. In this report, we present a case of a glioblastoma patient who was diagnosed at the age of 47 years with more than 20-year survival. We further discuss the suggested factors that may have contributed to a better prognosis with a focus on the possible role of varicella-zoster infection in mediating long-term survival.

A novel lncRNA ARST represses glioma progression by inhibiting ALDOA-mediated actin cytoskeleton integrity

Background

Glioma is one of the most aggressive malignant brain tumors that is characterized with inevitably infiltrative growth and poor prognosis. ARST is a novel lncRNA whose expression level is significantly decreased in the patients with glioblastoma multiforme. However, the exact mechanisms of ARST in gliomagenesis are largely unknown.

Methods

The expressions of ARST in the glioma samples and cell lines were analyzed by qRT-PCR. FISH was utilized to detect the distribution of ARST in the glioma cells. CCK-8, EdU and flow cytometry were used to examine cellular viability, proliferation and apoptosis. Transwell and wound-healing assays were performed to determine the migratory and invasive abilities of the cells. Intracranial tumorigenesis models were established to explore the roles of ARST in vivo. RNA pulldown assay was used to examine proteins that bound to ARST. The activities of key enzymes in the glycolysis and production of lactate acid were measured by colorimetry. In addition, RIP, Co-IP, western blot and immunofluorescence were used to investigate the interaction and regulation between ARST, F-actin, ALDOA and cofilin.

Results

In this study, we reported that ARST was downregulated in the gliomas. Overexpression of ARST in the glioma cells significantly suppressed various cellular vital abilities such as cell growth, proliferation, migration and invasion. The tumorigenic capacity of these cells in vivo was reduced as well. We further demonstrated that the tumor suppressive effects of ARST could be mediated by a direct binding to a glycolytic enzyme aldolase A (ALDOA), which together with cofilin, keeping the polymerization and depolymerization of actin filaments in an orderly dynamic equilibrium. Upregulation of ARST interrupted the interaction between ALDOA and actin cytoskeleton, which led to a rapid cofilin-dependent loss of F-actin stress fibers.

Conclusions

Taken together, it is concluded that ARST performs its function via a non-metabolic pathway associated with ALDOA, which otherwise modifies the morphology and invasive properties of the glioma cells. This has added new perspective to its role in tumorigenesis, thus providing potential target for glioma diagnosis, therapy, and prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01977-9.

CDK1 is up-regulated by temozolomide in an NF-κB dependent manner in glioblastoma

The alkylating agent, temozolomide (TMZ), is the most commonly used chemotherapeutic for the treatment of glioblastoma (GBM). The anti-glioma effect of TMZ involves a complex response that includes G2-M cell cycle arrest and cyclin-dependent kinase 1 (CDK1) activation. While CDK1 phosphorylation is a well-described consequence of TMZ treatment, we find that TMZ also robustly induces CDK1 expression. Analysis of this pathway demonstrates that CDK1 is regulated by NF-κB via a putative κB-site in its proximal promoter. CDK1 was induced in a manner dependent on mature p50 and the atypical inhibitor κB protein, BCL-3. Treatment with TMZ induced binding of NF-κB to the κB-site as assessed by gel shift analysis and chromatin immunoprecipitation. Examination of a CDK1 promoter-reporter demonstrated the functional relevance of the κB-site and underlined the requirement of p50 and BCL-3 for activation. Targeted knockdown of CDK1 or chemical inhibition with the selective CDK1 inhibitor, RO-3306, potentiated the cytotoxic effect of TMZ. These results identify CDK1 as an NF-κB target gene regulated by p50 and BCL-3 and suggest that targeting CDK1 may be a strategy to improve the efficacy of TMZ against GBM.

Cinnamaldehyde Inhibits the Function of Osteosarcoma by Suppressing the Wnt/β-Catenin and PI3K/Akt Signaling Pathways

BACKGROUND

Osteosarcoma (OS) is a primary bone tumor associated with locally aggressive growth and early metastatic potential that typically occurs in children and adolescents. Chinese traditional medicine Cinnamomum cassia Presl has been shown to have significant tumor-killing effect, in which cinnamaldehyde (CA) is the main active ingredient.

PURPOSE

To explore the anticancer effect of CA on the osteosarcoma cells and the possible molecular mechanism.

METHODS

Crystal violet assay, MTT assay and colony-forming assay were used to confirm the inhibitory role of CA in the proliferation of 143B and MG63 osteosarcoma cells. Hoechst 33258 staining and flow cytometry were used to observe apoptosis. The migration and invasion role of OS cells were evaluated using transwell assays and wound healing assays. Western blotting was used to analyse the protein expression levels. Nude mice were inoculated with 143B cells to establish an orthotopic OS tumor animal model and to investigate the effects of CA on OS tumors.

RESULTS

According to crystal violet assay, MTT assay and colony-forming assay, CA significantly inhibited cell proliferation. Hoechst 33258 staining and flow cytometry analysis showed that CA-induced apoptosis in a concentration-dependent manner. In addition, transwell assays and wound healing assays showed that CA inhibited the migration and invasion of osteosarcoma cells. In vivo mouse models, CA inhibited the growth of osteosarcoma. The potential mechanisms could be that CA inhibited the transcriptional activity of Wnt/β-catenin and PI3K/Akt of the osteosarcoma.

CONCLUSION

CA may inhibit the proliferation, migration, invasion and promote apoptosis of OS cells by inhibiting Wnt/β-catenin and PI3K/Akt signaling pathways. CA may be a potentially effective anti-tumor drug.

Knockdown of Tousled‑like kinase 1 inhibits survival of glioblastoma multiforme cells

Glioblastoma multiforme (GBM) is an aggressive type of brain tumour that commonly exhibits resistance to treatment. The tumour is highly heterogenous and complex kinomic alterations have been reported leading to dysregulation of signalling pathways. The present study aimed to investigate the novel kinome pathways and to identify potential therapeutic targets in GBM. Meta‑analysis using Oncomine identified 113 upregulated kinases in GBM. RNAi screening was performed on identified kinases using ON‑TARGETplus siRNA library on LN18 and U87MG. Tousled‑like kinase 1 (TLK1), which is a serine/threonine kinase was identified as a potential hit. In vitro functional validation was performed as the role of TLK1 in GBM is unknown. TLK1 knockdown in GBM cells significantly decreased cell viability, clonogenicity, proliferation and induced apoptosis. TLK1 knockdown also chemosensitised the GBM cells to the sublethal dose of temozolomide. The downstream pathways of TLK1 were examined using microarray analysis, which identified the involvement of DNA replication, cell cycle and focal adhesion signalling pathways. In vivo validation of the subcutaneous xenografts of stably transfected sh‑TLK1 U87MG cells demonstrated significantly decreased tumour growth in female BALB/c nude mice. Together, these results suggested that TLK1 may serve a role in GBM survival and may serve as a potential target for glioma.

Identification of potential crucial genes and molecular mechanisms in glioblastoma multiforme by bioinformatics analysis

Glioblastoma multiforme (GBM) is the most common and malignant brain tumor of the adult central nervous system and is associated with poor prognosis. The present study aimed to identify the hub genes in GBM in order to improve the current understanding of the underlying mechanism of GBM. The RNA-seq data were downloaded from The Cancer Genome Atlas database. The edgeR package in R software was used to identify differentially expressed genes (DEGs) between two groups: Glioblastoma samples and normal brain samples. Gene Ontology (GO) functional enrichment analysis and the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis were performed using Database for Annotation, Visualization and Integrated Discovery software. Additionally, Cytoscape and Search Tool for the Retrieval of Interacting Genes/Proteins tools were used for the protein-protein interaction network, while the highly connected modules were extracted from this network using the Minimal Common Oncology Data Elements plugin. Next, the prognostic significance of the candidate hub genes was analyzed using UALCAN. In addition, the identified hub genes were verified by reverse transcription-quantitative (RT-q) PCR. In total, 1,483 DEGs were identified between GBM and control samples, including 954 upregulated genes and 529 downregulated genes (P<0.01; fold-change >16) and these genes were involved in different GO terms and signaling pathways. Furthermore, CDK1, BUB1, BUB1B, CENPA and GNG3 were identified as key genes in the GBM samples. The UALCAN tool verified that higher expression level of CENPA was relevant to poorer overall survival rates. In conclusion, CDK1, BUB1, BUB1B, CENPA and GNG3 were found to be potential biomarkers for GBM. Additionally, ‘cell cycle’ and ‘γ-aminobutyric acid signaling’ pathways may serve a significant role in the pathogenesis of GBM.

Advancing towards Effective Glioma Therapy: MicroRNA Derived from Umbilical Cord Mesenchymal Stem Cells' Extracellular Vesicles

A glioma, especially a grade IV glioblastoma, is a malignant tumour with a poor prognosis despite growing medical advancements. Researchers have been looking for better and more effective treatments targeting the molecular pathways of gliomas due to glioblastomas’ ability to develop resistance to chemotherapies. Moreover, glioma stem cells (GSC) contribute to maintaining the glioma population, which benefits from its ability to self-renew and differentiate. Recent research has reported that through the introduction of umbilical cord mesenchymal stem cells (UCMSC) into glioma cells, the growth and development of the glioma cells can be downregulated. It has more currently been found out that UCMSC release extracellular vesicles (EVs) containing miRNA that are responsible for this phenomenon. Therefore, this review analyses literature to discuss all possible miRNAs contained within the UCMSC’s EVs and to elaborate on their molecular mechanisms in halting gliomas and GSC growth. This review will also include the challenges and limitations, to account for which more in vivo research is suggested. In conclusion, this review highlights how miRNAs contained within UCMSC’s EVs are able to downregulate multiple prominent pathways in the survival of gliomas.

Discovery of an Indirubin Derivative as a Novel c-Met Kinase Inhibitor with In Vitro Anti-Tumor Effects

The c-Met protein is a receptor tyrosine kinase involved in cell growth, proliferation, survival, and angiogenesis of several human tumors. Overexpression of c-Met has been found in gastric cancers and correlated with a poor prognosis. Indirubin is the active component of Danggui Longhui Wan, which is a traditional Chinese antileukemic recipe. In the present study, we tested the anti-cancer effects of an indirubin derivative, LDD-1937, on human gastric cancer cells SNU-638. When we performed the in vitro kinase assay against the c-Met activity, LDD-1937 inhibited the activity of c-Met. This result was confirmed by immunoblot and immunofluorescence of phosphorylated c-Met. Immunoblot analysis showed that LDD-1937 decreased the expression of the Erk1/2, STAT3, STAT5, and Akt, downstream proteins of c-Met. In addition, LDD-1937 reduced the cell viability and suppressed colony formation and migration of SNU-638 cells. Furthermore, LDD-1937 induced G₂/M phase arrest in the SNU-638 cells by decreasing the expression levels of cyclin B1 and CDC2. Cleaved-PARP, an apoptosis-related protein, was up-regulated in cells treated with LDD-1937. Overall, this study suggests that LDD-1937 may be a novel small-molecule with therapeutic potential for selectively inhibiting c-Met and c-Met downstream pathways in human gastric cancers overexpressing c-Met.

Comprehensive analysis of Reverse Phase Protein Array data reveals characteristic unique proteomic signatures for glioblastoma subtypes

The most common and lethal type of intracranial tumors include the astrocytomas. Grade IV astrocytoma or Glioblastoma (GBM) is highly aggressive and treatment-refractory with a median survival of only 14 to 16 months. Molecular profiling of GBMs reveals a high degree of intra- and inter-tumoral heterogeneity, and hence it is important to understand the important signalling axes that get deregulated in different GBM subtypes to provide effective tailor-made therapies. In this study, we have carried out extensive analysis of Reverse Phase Protein Array (RPPA) data from TCGA cohort to develop protein signatures that define glioma grades or subtypes. The protein signatures that distinguished Grade II or III from GBM had largely overlapped, and pathway analysis revealed the positive enrichment of extracellular matrix proteins (ECM), MYC pathway, uPAR pathway and G2/M checkpoint genes in GBM. We also identified protein signatures for GBMs with genetic alterations (IDH mutation, p53 mutation, EGFR amplification or mutation, CDKN2A/CDKN2B deletion, and PTEN mutation) that occur at high frequency. G-CIMP positive GBM-specific protein signature showed a large similarity with IDH1-mutant protein signature, thus signifying the importance of IDH1 mutation driving the G-CIMP. Gene expression subtype analysis revealed an association of specific proteins to classical (EGFR and phosphor variants), mesenchymal (SERPINE1, TAZ, and Myosin-IIa_pS1943), neural (TUBA1B), and proneural (GSK3_pS9) types. Univariate Cox regression analysis identified several proteins showing significant correlation with GBM survival. Multivariate analysis revealed that IGFBP2 and RICTOR_pT1135 are independent predictors of survival. Overall, our analyses reveal that specific proteins are regulated in different glioma subtypes underscoring the importance of diverse signalling axes playing important role in the pathogenesis of glioma tumors.

Down-regulation of miRNA-320c promotes tumor growth and metastasis and predicts poor prognosis in human glioma

Emerging studies show that dysregulated miRNAs are implicated in tumorigenesis and progression of various cancers. MiRNA-320c, an important member of miRNA-320 family, was characterized as a new candidate miRNA that suppressed the development of colorectal cancer and bladder cancer. However, the function of miRNA-320c in human glioma remained unclear. Here, we found that miRNA-320c was significantly down-regulated in glioma tissues in contrast with normal brain tissues, being tightly related to clinical stage of glioma by qRT-PCR. Moreover, Kaplan-Meier analysis demonstrated that patients with low miRNA-320c expression had a shorter survival. Multivariate Cox regression analysis indicated that miRNA-320c could serve as an independent poor prognostic factor for patients with glioma. Functionally, overexpression of miRNA-320c could dramatically inhibit glioma cell proliferation, migration and invasion, as well as promote apoptosis. Further analysis indicated that overexpression of miRNA-320c dramatically led to the G0/G1 phase arrest and correspondingly decreased the percentage of S phase cells by suppressing the expression of G1/S transition key regulators, such as Cyclin D1 and CDK6. Additionally, up-regulation of miRNA-320c could significantly impair migration and invasion of glioma cells via reducing the expression of MMP2, MMP9, N-cadherin and Integrin β1. Collectively, our data revealed that miRNA-320c played a crucial role in the carcinoma processes of glioma and might serve as a new prognosis biomarker and therapeutic target of glioma.

PRAJA is overexpressed in glioblastoma and contributes to neural precursor development

PRAJA, a RING-H2 E3 ligase, is abundantly expressed in brain tissues such as the cerebellum and frontal cortex, amongst others, and more specifically in neural progenitor cells as well as in multiple cancers that include glioblastomas. However, the specific role that Praja plays in neural development and gliomas remains unclear. In this investigation, we performed bioinformatic analyses to examine Praja1 and Praja2 expression across 29 cancer types, and observed raised levels of Praja1 and Praja2 in gliomas with an inverse relationship between Praja1 and apoptotic genes and Praja substrates such as Smad3. We analyzed the role of Praja in the developing brain through loss of function studies, using morpholinos targeting Praja1 in embryonic zebrafish, and observed that Praja1 is expressed prominently in regions enriched with neural precursor cell subtypes. Antisense Praja morpholinos resulted in multiple embryonic defects including delayed neural development likely through increased apoptosis. Further studies revealed high levels of Cdk1 with loss of Praja1 in TGF-β or insulin treated cells, supporting the link between Praja1 and cell cycle regulation. In summary, these studies underscore Praja's role in mammalian brain development and Praja1 deregulation may lead to gliomas possibly through the regulation of cell cycle and/or apoptosis.

Astaxanthin increases radiosensitivity in esophageal squamous cell carcinoma through inducing apoptosis and G2/M arrest

Nowadays esophageal squamous cell carcinoma (ESCC) is primarily treated by a comprehensive approach combining surgical resection and neoadjuvant chemo- or radiotherapy. However, ESCC is resistant to radiation therapy, resulting in its invasion, infiltration, and metastasis. It usually has rapidly progressed and has a poor outcome clinically. The purpose of this study is to determine the potential radiosensitizing effect of astaxanthin (ATX) and explore the underlying mechanisms in ESCC cells in vitro. ESCC cell lines were exposure to irradiation, in the presence or absence of ATX treatment. Cell viability and radiosensitization were tested by CCK8 assay and clonogenic survival assay, respectively. Cell apoptosis and the changes of cell cycle distribution were observed by flow cytometry. The protein expression of Bcl2, Bax, CyclinB1, and Cdc2 was examined by western blot analysis. It was shown that ATX improved radiosensitivity of ESCC cells and induced apoptosis and G2/M arrest via inhibiting Bcl2, CyclinB1, Cdc2, and promoting Bax expression. In conclusion, ATX might function as a promising radiosensitizer in ESCC cells by leading to apoptosis and G2/M arrest.

Silencing platelet-derived growth factor receptor-β enhances the radiosensitivity of C6 glioma cells in vitro and in vivo

Platelet-derived growth factor receptor (PDGFR)-β is an important tyrosine kinase and its downregulation has been reported to alter the radiosensitivity of glioma cells, although the underlying mechanism is unclear. In order to investigate the effect of PDGFR-β on the radiosensitivity of glioblastoma, the present study transfected C6 glioma cells with a PDGFR-β-specific small interfering (si)RNA expression plasmid, and downregulation of the expression of PDGFR-β in C6 glioma cells was confirmed by western blotting and immunohistochemical analysis. Clone formation assays and xenograft growth curves demonstrated that PDGFR-β-siRNA enhanced the radiosensitivity of C6 glioma cells in vitro and in vivo. Furthermore, MTT and xenograft growth curves demonstrated that PDGFR-β-siRNA inhibited the proliferation of C6 glioma cells in vitro and in vivo, and terminal deoxynucleotidyl transferase dUTP nick end-labeling and immunohistochemical analyses demonstrated that PDGFR-β-siRNA induced apoptosis and inhibited the expression of Ki-67, cyclin B1 and vascular endothelial growth factor in C6 glioma cell xenografts. Taken together, these results suggested that PDGFR-β may be used as a target for the radiosensitization of glioblastoma.

15α-methoxypuupehenol Induces Antitumor Effects In Vitro and In Vivo against Human Glioblastoma and Breast Cancer Models

Studies with 15α-methoxypuupehenol (15α-MP), obtained from the extracts of Hyrtios species, identified putative targets that are associated with its antitumor effects against human glioblastoma and breast cancer. In the human glioblastoma (U251MG) or breast cancer (MDA-MB-231) cells, treatment with 15α-MP repressed pY705Stat3, pErk1/2, pS147CyclinB1, pY507Alk (anaplastic lymphoma kinase), and pY478ezrin levels and induced pS10merlin, without inhibiting pJAK2 (Janus kinase) or pAkt induction. 15α-MP treatment induced loss of viability of breast cancer (MDA-MB-231, MDA-MB-468) and glioblastoma (U251MG) lines and glioblastoma patient-derived xenograft cells (G22) that harbor aberrantly active Stat3, with only moderate or little effect on the human breast cancer, MCF7, colorectal adenocarcinoma Caco-2, normal human lung fibroblast, WI-38, or normal mouse embryonic fibroblast (MEF Stat3^fl/fl) lines that do not harbor constitutively active Stat3 or the Stat3-null (Stat3^-/-) mouse astrocytes. 15α-MP-treated U251MG cells have severely impaired F-actin organization and altered morphology, including the cells rounding up, and undergo apoptosis, compared with a moderate, reversible morphology change observed for similarly treated mouse astrocytes. Treatment further inhibited U251MG or MDA-MB-231 cell proliferation, anchorage-independent growth, colony formation, and migration in vitro while only moderately or weakly affecting MCF7 cells or normal mouse astrocytes. Oral gavage delivery of 15α-MP inhibited the growth of U251MG subcutaneous tumor xenografts in mice, associated with apoptosis in the treated tumor tissues. Results together suggest that the modulation of Stat3, CyclinB1, Alk, ezrin, merlin, and Erk1/2 functions contributes to the antitumor effects of 15α-MP against glioblastoma and breast cancer progression. Mol Cancer Ther; 16(4); 601-13. ©2017 AACR.

MicroRNA-219-5p Inhibits Morphine-Induced Apoptosis by Targeting Key Cell Cycle Regulator WEE1

BACKGROUND To identify the effects of microRNA (miR)-219-5p on morphine-induced apoptosis by targeting WEE1. MATERIAL AND METHODS Forty Balb/C mice (Toll-like receptor 9, TLR9 knockout) were randomly allocated to the experimental and control groups (20 in each group). The baseline miR-219-5p expression was detected using quantitative real-time PCR (qRT-PCR). After morphine was injected at 6 h on the 2nd and 6th days, experimental and control groups received miR-219-5p mimics or miRNA-negative control (NC), respectively, compound injection. Tissues and cells were later obtained from subjects in each group separately after mice were killed. TUNEL assay was used to investigate apoptosis in both groups. RAW264.7 cells were treated with miR-219-5p mimics and controls, respectively. After 24 h, 10 μM of morphine was added at 24 h. Cell apoptosis was assessed by flow cytometer. The WEE1 and Phospho-cdc2 (Tyr15) expressions were examined by Western blotting. RESULTS MiR-219-5p expression in the experimental group was significantly lower than that in the control group (P<0.05). Mice injected with miR-219-5p mimic experienced an evident increase in apoptosis rate compared with the control group (P<0.05). The miR-219-5p NC group and the morphine group both presented an elevated apoptosis rate compared with the blank control group (both, P<0.05). The apoptosis rate in the miR-219-5p mimic group was 10.06%, remarkably lower than in the miR-219-5p NC group and blank control group (both P<0.05). WEE1 and Tyr15 protein expressions in the miR-219-5p NC group and morphine group were obviously stronger than those in the blank control group (all P<0.05). In the miR-219-5p mimic group, WEE1 and Tyr15 protein expressions were significantly lower compared with those in the miR-219-5p NC group and morphine group (all P<0.05). CONCLUSIONS Morphine significantly downregulated the expression of miRNA-219-5p, which targets WEE1 to suppress Tyr15 expressions and activate Cdc2, thus inhibiting the morphine-induced macrophage apoptosis.

Molecular mechanisms underlying mangiferin-induced apoptosis and cell cycle arrest in A549 human lung carcinoma cells

Mangiferin, which is a C-glucosylxanthone (1,3,6,7-tetrahydroxyxanthone-C2-β-D-glucoside) purified from plant sources, has recently gained attention due to its various biological activities. The present study aimed to determine the apoptotic effects of mangiferin on A549 human lung adenocarcinoma cells. In vitro studies demonstrated that mangiferin exerted growth-inhibitory and apoptosis-inducing effects against A549 cells. In addition, mangiferin exhibited anti-tumor properties in A549 xenograft mice in vivo. Mangiferin triggered G₂/M phase cell cycle arrest via down-regulating the cyclin-dependent kinase 1-cyclin B1 signaling pathway, and induced apoptotic cell death by inhibiting the protein kinase C-nuclear factor-κB pathway. In addition, mangiferin was able to enhance the antiproliferative effects of cisplatin on A549 cells, thus indicating the potential for a combined therapy. Notably, mangiferin exerted anticancer effects in vivo, where it was able to markedly decrease the volume and weight of subcutaneous tumor mass, and expand the lifespan of xenograft mice. The present study clarified the molecular mechanisms underlying mangiferin-induced antitumor activities, and suggested that mangiferin may be considered a potential antineoplastic drug for the future treatment of cancer.

Cytotoxic withanolides from Physalis angulata var. villosa and the apoptosis-inducing effect via ROS generation and the activation of MAPK in human osteosarcoma cells

Physagulide I induced apoptosis and cell cycle arrest via ROS generation and the activation of MAPK in human osteosarcoma cells.

Influence of Toxoplasma gondii on in vitro proliferation and apoptosis of hepatoma carcinoma H7402 cell

OBJECTIVE

To discuss the influence of tachyzoite of Toxoplasma gondii (T. gondii) RH strain on proliferation and apoptosis of hepatoma carcinoma (HCC) H7402 cell.

METHODS

The HCC H7402 cell in logarithmic phase and tachyzoite of T. gondii RH strain in different concentrations (1 × 10(7)/mL, 2 × 10(7)/mL, 4 × 10(7)/mL, 8 × 10(7)/mL and 16 × 10(7)/mL) were co-cultured. CCK-8 was utilized to determine the inhibition rate of T. gondii tachyzoite on H7402 cell growth. Flow cytometry was used to detect the change of cell cycle. RT-PCR method was used to detect the expression of cyclinB1 and cdc2-two genes related to cell cycle. Western blot method was used to detect the expression of apoptosis-related proteins Caspase-3 and Bcl-2.

RESULTS

The tachyzoite of T. gondii RH strain can inhibit the proliferation of HCC H7402 cells. The inhibition rate of tumor cell growth increased with the increase of concentration of T. gondii tachyzoite. With the increase of concentration of T. gondii tachyzoite, the proportion of G0/G1 phase of H7402 cell increased, the proportion of S phase decreased, and PI value decreased accordingly. The expression of cyclinB1 and cdc2 genes decreased with the increase of the concentration of T. gondii tachyzoite. With the increase of the concentration of tachyzoite of T. gondii RH strain, the expression quantity of Caspase-3 in H7402 cell increased, but the expression quantity of Bcl-2 protein decreased.

CONCLUSIONS

T. gondii can inhibit the in vitro proliferation of HCC H7402 cell, and induce its apoptosis. This effect shows a trend of concentration-dependent increase. Moreover, it is related to the down-regulation of cyclinB1 and cdc2 (cell cycle-related genes), the increase of apoptosis-related protein Caspase-3, and the decrease of Bcl-2 expression.

Significance of expression of CyclinB1, CDK1, p53, and Rb in esophageal oncogenesis

AIM: To detect the expression of CyclinB1, cyclin-dependent kinases 1 (CDK1), p53, and Rb in esophageal oncogenesis and to analyze their clinical significance.

METHODS: Thirty-five cases of esophageal squamous cell carcinoma (each case simultaneously had carcinoma, intraepithelial neoplasia and normal mucosa) were selected and used to prepare tissue chips. The changes of CyclinB1, CDK1, p53 and Rb protein expression in the evolution of esophageal squamous cell carcinoma were observed immunohistochemically and their correlations were analyzed.

RESULTS: The positive expression rates of CyclinB1, CDK1 and p53 were significantly higher in esophageal squamous cell carcinoma than in normal esophageal mucosa, low- and high-grade intraepithelial neoplasia (P < 0.05). The positive expression rate of Rb was similar between esophageal squamous cell carcinoma and high grade intraepithelial neoplasia (P > 0.05), but differed significantly in other pairwise comparisons (P < 0.01). CyclinB1, CDK1, p53 and Rb expression had a significantly positive correlation in esophageal squamous cell carcinoma (P < 0.01).

CONCLUSION: In esophageal oncogenesis, CyclinB1, CDK1, p53 and Rb are overexpressed and have synergistic action. As esophageal intraepithelial neoplasia progresses, Rb protein is overexpressed, which is the early event in gastric oncogenesis of esophageal epithelia. The combined detection of CyclinB1, CDK1, p53 and Rb protein expression will contribute to the early diagnosis and evaluation of esophageal carcinoma.

Targeting cell cycle regulators in hematologic malignancies

Hematologic malignancies represent the fourth most frequently diagnosed cancer in economically developed countries. In hematologic malignancies normal hematopoiesis is interrupted by uncontrolled growth of a genetically altered stem or progenitor cell (HSPC) that maintains its ability of self-renewal. Cyclin-dependent kinases (CDKs) not only regulate the mammalian cell cycle, but also influence other vital cellular processes, such as stem cell renewal, differentiation, transcription, epigenetic regulation, apoptosis, and DNA repair. Chromosomal translocations, amplification, overexpression and altered CDK activities have been described in different types of human cancer, which have made them attractive targets for pharmacological inhibition. Mouse models deficient for one or more CDKs have significantly contributed to our current understanding of the physiological functions of CDKs, as well as their roles in human cancer. The present review focuses on selected cell cycle kinases with recent emerging key functions in hematopoiesis and in hematopoietic malignancies, such as CDK6 and its role in MLL-rearranged leukemia and acute lymphocytic leukemia, CDK1 and its regulator WEE-1 in acute myeloid leukemia (AML), and cyclin C/CDK8/CDK19 complexes in T-cell acute lymphocytic leukemia. The knowledge gained from gene knockout experiments in mice of these kinases is also summarized. An overview of compounds targeting these kinases, which are currently in clinical development in various solid tumors and hematopoietic malignances, is presented. These include the CDK4/CDK6 inhibitors (palbociclib, LEE011, LY2835219), pan-CDK inhibitors that target CDK1 (dinaciclib, flavopiridol, AT7519, TG02, P276-00, terampeprocol and RGB 286638) as well as the WEE-1 kinase inhibitor, MK-1775. The advantage of combination therapy of cell cycle inhibitors with conventional chemotherapeutic agents used in the treatment of AML, such as cytarabine, is discussed.

MicroRNA-584 functions as a tumor suppressor and targets PTTG1IP in glioma

MicroRNAs (miRNAs) are small noncoding RNA molecules that regulate gene expression at the post transcriptional level. Compelling evidence shows that there are causative links between miRNAs deregulation and cancer development and progression. In this study, we demonstrated that miR-584 was downregulated in human glioma and could suppress growth of the human glioma cell line U87-MG and U251-MG. Bioinformatics analysis indicated that PTTG1IP was a putative target of miR-584. In a Luciferase reporter system, we confirmed that PTTG1IP was a direct target gene of miR-584. These findings indicate that miR-584 suppresses glioma cell growth by negatively regulating the expression of PTTG1IP, suggesting that miR-584 has a tumor suppressive role in human glioma pathogenesis.

Knockdown of CDC2 expression inhibits proliferation, enhances apoptosis, and increases chemosensitivity to temozolomide in glioblastoma cells

Cell division cycle 2 (CDC2) is always overexpressed in malignant tumor cells and is correlated with chemosensitivity, but it is unclear whether CDC2 overexpression contributes to the chemoresistance potential of glioma cells. The aim of study was to determine the relationship of CDC2 expression with the prognosis and chemoresistance of glioblastoma. In this study, the glioblastoma U87 and U251 cell lines were steadily transfected with a lentivirus vector expressing a short hairpin RNA-targeting CDC2. Expression of CDC2 was evaluated in glioblastoma and cell lines by immunohistochemistry and Western blot analysis. The relationship between CDC2 expression and clinicopathological characteristics was analyzed. Using RNA interference, the effects of CDC2 on chemosensitivity to temozolomide (TMZ) were investigated in U87 and U251 cell lines in vitro. Combined CDC2 knockdown and TMZ treatment inhibited cell proliferation and induced apoptosis in vitro more effectively than either treatment alone. qRT-PCR and Western blot analysis showed that cells underexpressing CDC2 revealed lower expression of the anti-apoptotic protein B cell lymphoma-2 and increased expression of the apoptosis effector caspase-3 compared to U87 and U251 cells transfected with a control vector. Furthermore, expression levels of CDC2 in U87 and U251 cells were related to the IC50 of the antitumor drug TMZ. Knockdown of CDC2 expression was associated with decreased expression of Ral-binding protein 1, a classical chemotherapy drugs transporter. These results indicate that the ability to suppress the malignant phenotype by down-regulating CDC2 expression may provide a new gene therapy approach for overcoming CDC2-associated chemoresistance in patients with malignant glioma.

Association study of germline variants in CCNB1 and CDK1 with breast cancer susceptibility, progression, and survival among Chinese Han women

The CCNB1 and CDK1 genes encode the proteins of CyclinB1 and CDK1 respectively, which interact with each other and are involved in cell cycle regulation, centrosome duplication and chromosome segregation. This study aimed to investigate whether the genetic variants in these two genes may affect breast cancer (BC) susceptibility, progression, and survival in Chinese Han population using haplotype-based analysis. A total of ten tSNPs spanning from 2kb upstream to 2kb downstream of these genes were genotyped in 1204 cases and 1204 age-matched cancer-free controls. The haplotype blocks were determined according to our genotyping data and linkage disequilibrium (LD) status of these SNPs. For CCNB1, rs2069429 was significantly associated with increased BC susceptibility under recessive model (OR=2.352, 95%CI=1.480-3.737), so was the diplotype TAGT/TAGT (OR=1.947 95%CI=1.154-3.284, P=0.013). In addition, rs164390 was associated with Her2-negative BC. For CDK1, rs2448343 and rs1871446 were significantly associated with decreased BC risk under dominant models, so was the haplotype ATATT. These two SNPs also showed a dose-dependent effect on BC susceptibility. Using stratified association analysis, we found that women with the heterozygotes or minor allele homozygotes of rs2448343 had much less BC susceptibility among women with BMI<23. In CDK1, three closely located SNPs, rs2448343, rs3213048 and rs3213067, were significantly associated with tumor’s PR status: the heterozygotes of rs2448343 were associated with PR-positive tumors, while the minor allele homozygotes of rs3213048 and heterozygotes of rs3213067 were associated with PR-negative BC tumors. In survival analysis, rs1871446 was associated with unfavorable event-free survival under recessive model, so was the CDK1 diplotype ATATG/ATATG, which carried the minor allele homozygote of rs1871446. Our study indicates that genetic polymorphisms of CCNB1 and CDK1 are related to BC susceptibility, progression, and survival in Chinese Han women. Further studies need to be performed in other populations as an independent replication to verify these results.

Overexpression of p42.3 promotes cell growth and tumorigenicity in hepatocellular carcinoma

AIM: To investigate the association of p42.3 expression with clinicopathological characteristics and the biological function of p42.3 in human hepatocellular carcinoma (HCC).

METHODS: We used reverse transcription-polymerase chain reaction (RT-PCR), quantitative real-time RT-PCR and western blotting to detect p42.3 mRNA and protein expression in hepatic cell lines. We examined primary HCC samples and matched adjacent normal tissue by immunohistochemistry to investigate the correlation between p42.3 expression and clinicopathological features. HepG2 cells were transfected with a pIRES2-EGFP-p42.3 expression vector to examine the function of the p42.3 gene. Transfected cells were analyzed for their viability and malignant transformation abilities by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, colony formation assay, and tumorigenicity assay in nude mice.

RESULTS: p42.3 is differentially expressed in primary HCC tumors and cell lines. Approximately 69.6% (96/138) of cells were p42.3-positive in hepatic tumor tissues, while 30.7% (35/114) were p42.3-positive in tumor-adjacent normal tissues. Clinicopathological characteristics of the HCC specimens revealed a significant correlation between p42.3 expression and tumor differentiation (P = 0.031). However, p42.3 positivity was not related to tumor tumor-node-metastasis classification, hepatitis B virus status, or hepatoma type. Regarding p42.3 overexpression in stably transfected HepG2 cells, we discovered significant enhancement of cancer cell growth and colony formation in vitro, and significantly enhanced tumorigenicity in nude mice. Western blot analysis of cell cycle proteins revealed that enhanced p42.3 levels promote upregulation of proliferating cell nuclear antigen, cyclin B1 and mitotic arrest deficient 2.

CONCLUSION: p42.3 promotes tumorigenicity and tumor growth in HCC and may be a potential target for future clinical cancer therapeutics.

Effects of siRNA‑mediated Cdc2 silencing on MG63 cell proliferation and apoptosis

The present study aimed to determine the effect of small interfering RNA (siRNA)‑induced inhibition of cyclin‑dependent kinase 2 (Cdc2) expression on osteosarcoma MG63 cell proliferation and apoptosis. An siRNA expression plasmid, psilencer 2.1‑U6/Cdc2, targeting the Cdc2 gene, and a control psilencer 2.1‑U6/Scramble plasmid were constructed and transfected into MG63 cells using liposomes. Cdc2 expression in the MG63 cells was investigated by western blot analysis and real‑time polymerase chain reaction. Cell morphology was also examined. The effects of psilencer 2.1‑U6/Cdc2 on MG63 cell proliferation and the cell cycle were detected via MTT and flow cytometry, respectively. Expression levels of apoptosis‑related molecules, B‑cell lymphoma 2 (Bcl‑2) and Bcl‑2‑associated X (Bax) were determined by western blot analysis. MG63 cells stably transfected with the psilencer 2.1‑U6/Cdc2 plasmid (MG63‑siRNA/Cdc2) and negative control cells, MG63‑siRNA/Scramble, were successfully obtained. The silencing efficiencies of the Cdc2‑expressing mRNA and protein in MG63‑siRNA/Cdc2 were 86 and 89% of that of the control MG63‑siRNA/Scramble cells, respectively. Interference of Cdc2 expression inhibited MG63 cell proliferation and was demonstrated to significantly increase and decrease cells in the G2/M and S phases, respectively. Cdc2 expression silencing had negligible effects on Bcl‑2 and Bax expression in MG63 cells. In conclusion, silencing of Cdc2 expression suppresses proliferation of osteosarcoma MG63 cells but has negligible effects on apoptosis.

Three meta-analyses define a set of commonly overexpressed genes from microarray datasets on astrocytomas

Glioma is one of the most common tumors of the central nervous system, and one of its main types is astrocytoma. Microarray technology has been widely used to explore the molecular mechanism of cancer. It is universally accepted that meta-analysis considerably improves the statistical robustness of results, particularly in clinical research. To obtain the maximum reliability, we used three different meta-analyses to integrate the four microarray datasets, GSE16011, GSE4290, GSE2223, and GSE19728 (local), and defined the common differentially expressed genes (DEGs) in astrocytomas compared with normal brain tissue. Four DEGs, PCNA, CDC2, CDK2 and CCNB2, which are components of the cell cycle pathway, were chosen for Real-Time Polymerase Chain Reaction (RT-PCR) and immunohistochemistry validation. PCNA is similar to the P53 gene and has been widely implicated in various cancers including gliomas. Therefore, the expression status of PCNA in our study was considered as a reference to test our whole experimental scheme, and the results indicate that our methodology is valid. Although a few studies have reported the overexpression of the CDC2, CDK2 and CCNB2 genes in glioma cell lines, we are the first to identify the statuses of these genes in human astrocytoma tissues at the mRNA and protein levels. The results of the gene validations strongly suggested that the genes play an important role in astrocytomas and could potentially be valuable in the diagnosis and treatment of astrocytoma.

Molecular resistance fingerprint of pemetrexed and platinum in a long-term survivor of mesothelioma

Background

Pemetrexed, a multi-folate inhibitor combined with a platinum compound is the first-line treatment of malignant mesothelioma, but median survival is still one year. Intrinsic and acquired resistance to pemetrexed is common, but its biological basis is obscure. Here we report for the first time a genome-wide profile of acquired resistance in the tumour from an exceptional case with advanced pleural mesothelioma and almost six years survival after 39 cycles of second-line pemetrexed/carboplatin treatment.

Methodology and Principal Findings

Genome-wide analysis with Illumina BeadChip Kit of 25,000 genes was performed on mRNA from pre-treatment and post-resistance biopsies from this individual as well on case and control samples from our previously published study (in total 17 samples). Cell specific expression of proteins encoded by selected genes were analysed by immunohistochemistry. Serial serum levels of CA125, CYFRA21-1 and SMRP levels were examined. TS protein, the main target of pemetrexed was overexpressed. Proteins and genes related to DNA damage response, elongation and telomere extension and repair related directly and indirectly to platinum resistance were overexpressed, as the CHK1 protein and the genes CHEK2, LIG3, POLD1, POLA2, FANCD2, PRPF19, RECQ5 respectively, the last two not previously described in mesothelioma. We observed a down-regulation of leukocyte transendothelial migration and cell adhesion molecules pathways. Silencing of NT5C in two mesothelioma cell lines did not sensitize the cells to Pemetrexed. Proposed resistance markers are TS, KRT7/ CK7, TYMP/ thymidine phosphorylase and down-regulated SPARCL1 and CDKN1B. Moreover, comparison of the primary expression of the sensitive versus a primary resistant case showed multi-fold overexpressed DNA repair, cell cycle, cytokinesis, and spindle formation in the latter. Serum CA125 and SMRP reflected the clinical and radiological course and tumour burden.

Conclusions

Genome-wide microarray of mesothelioma pre- and post-resistance biopsies indicated a novel resistance signature to pemetrexed/carboplatin that deserve validation in a larger cohort.

iTRAQ analysis of a cell culture model for malignant transformation, including comparison with 2D-PAGE and SILAC

To study human cancer development, cell culture models for malignant transformation can be used. In 1999 Hahn and Coworkers introduced such a model system and established herewith a basis for research on human tumorigenesis. Primary human fibroblasts are sequentially transduced with defined genetic elements (hTERT, SV40 ER, and H-RasV12), resulting in four defined cell lines, whereby the last has a fully transformed phenotype. In order to get a deeper insight into the molecular biology of human tumorigenesis, we compared the proteomes of these four cell lines following a multimethod concept. At the beginning we assumed SILAC and sample fractionation with COFRADIC is the method of choice to analyze the cell culture model for malignant transformation. Here, the compared samples are combined before sample preparation, thus avoiding differences in sample preparation, and using COFRADIC notably reduces sample complexity. Because 2D-PAGE is a standard method for the separation and visualization of closely related proteomes, we decided to analyze and compare the proteomes of these four cell lines in a first approach by differential 2D-PAGE. Surprisingly, we discovered much more unique results with iTRAQ and sample fractionation with SCX than with the combination of 2D-PAGE and SILAC-COFRADIC. Moreover, iTRAQ outperforms the other strategies not only in number of yielded results but also in analysis time. Here, we present the iTRAQ quantification results and compare them with the results of 2D-PAGE and SILAC-COFRADIC. We found changes in the protein level at each transition. Thereby, SV40 has the strongest impact on the proteome. In detail we identified 201 regulated proteins. Beside others, these proteins are involved in cytoskeleton, RNA processing, and cell cycle, such as CDC2, hnRNPs, snRNPs, collagens, and MCM proteins. For example, MCM proteins are up-regulated and collagens are down-regulated due to SV40 ER expression. Furthermore we made the observation that proteins containing the same domain have analogous regulation profiles during malignant transformation. For instance, several proteins containing a CH or LIM domain are down-regulated. Moreover, by this study and the defined cell culture model, changes could be clearly matched to specific steps during tumorigenesis.

Downregulation of GRIM-19 promotes growth and migration of human glioma cells

It has become increasingly clear that there are notable parallels between normal development and tumorigenesis. Glioma is a classic model that links between tumorigenesis and development. We evaluated the expression of GRIM-19, a novel gene essential for normal development, in various grades of gliomas and several human glioma cell lines. We showed that GRIM-19 mRNA and protein expression were markedly lower in gliomas than in control brain tissues and negatively correlated with the malignancy of gliomas. Downregulation of GRIM-19 in glioma cells significantly enhanced cell proliferation and migration, whereas overexpression of GRIM-19 showed the opposite effects. We also showed that the activation of signal transducer and activator of transcription 3 (STAT3) and the expression of many STAT3-dependent genes were regulated by the expression of GRIM-19. In addition, GRIM-19 exerted its role probably through the non-STAT3 signaling pathway. Collectively, our data suggest that most gliomas expressed GRIM-19 at low levels, which may play a major role in tumorigenesis in the brain.

Candidate genes influencing sensitivity and resistance of human glioblastoma to Semustine

OBJECTIVE

The prognosis of glioblastoma (GBM) is poor. The therapeutic outcome of conventional surgical and adjuvant treatments remains unsatisfactory, and therefore individualized adjuvant chemotherapy has aroused more attention. Microarrays have been applied to study mechanism of GBM development and progression but it has difficulty in determining responsible genes from the plethora of genes on microarrays unrelated to outcome. The present study was attempted to use bioinformatics method to investigate candidate genes that may influence chemosensitivity of GBM to Semustine (Me-CCNU).

METHODS

Clinical data of 4 GBM patients in Affymetrix microarray were perfected through long-term follow-up study. Differential expression genes between the long- and short-survival groups were picked out, GO-analysis and pathway-analysis of the differential expression genes were performed. Me-CCNU-related signal transduction networks were constructed. The methods combined three steps before were used to screen core genes that influenced Me-CCNU chemosensitivity in GBM.

RESULTS

In Affymetrix microarray there were altogether 2018 differential expression genes that influenced survival duration of GBM. Of them, 934 genes were up-regulated and 1084 down-regulated. They mainly participated in 94 pathways. Me-CCNU-related signal transduction networks were constructed. The total number of genes in the networks was 466, of which 66 were also found in survival duration-related differential expression genes. Studied key genes through GO-analysis, pathway-analysis and in the Me-CCNU-related signal transduction networks, 25 core genes that influenced chemosensitivity of GBM to Me-CCNU were obtained, including TP53, MAP2K2, EP300, PRKCA, TNF, CCND1, AKT2, RBL1, CDC2, ID2, RAF1, CDKN2C, FGFR1, SP1, CDK6, IGFBP3, MDM4, PDGFD, SOCS2, CCNG2, CDK2, SDC2, STMN1, TCF7L1, TUBB.

CONCLUSION

Bioinformatics may help excavate and analyze large amounts of data in microarrays by means of rigorous experimental planning, scientific statistical analysis and collection of complete data about survival of GBM patients. In the present study, a novel differential gene expression pattern was constructed and advanced study will provide new targets for chemosensitivity of GBM.

Essential role of the Hedgehog signaling pathway in human glioma-initiating cells

Recent findings have demonstrated that malignant tumors, including glioblastoma multiforme, contain cancer-initiating cells (also known as cancer stem cells), which self-renew and are malignant, with features of tissue-specific stem cells. As these cells are resistant to irradiation and anti-cancer drugs, it is important to characterize them and find targeting therapies. In this study, we established two primary human glioma cell lines from anaplastic oligodendroglioma and glioblastoma multiforme. These lines were enriched in glioma-initiating cells, as just 10 cells formed malignant glioma when injected into mouse brain. We used these cell lines to examine the roles of the Notch, Hedgehog and Wnt signaling pathways, which are involved in stem-cell maintenance and tumorigenesis, to determine which of these pathways are crucial to glioma-initiating cells and their regulation. Here we show that the Hedgehog pathway is indispensable for glioma-initiating cell proliferation and tumorigenesis; the Hedgehog signaling inhibitors prevented glioma-initiating cell proliferation, while signaling inhibitors for Notch or Wnt did not. Overexpression of Gli2ΔC, a C-terminal-truncated form of Gli2 that antagonizes Gli transcription factor functions, blocked glioma-initiating cell proliferation in culture and tumorigenesis in vivo. Knockdown of the Gli downstream factor Cdc2 also prevented glioma-initiating cell proliferation. Taken together, these results show that the Hedgehog→ Gli→Cdc2 signaling cascade plays a role in the proliferation and malignancy of glioma-initiating cells.

Integrative analysis of many weighted co-expression networks using tensor computation

The rapid accumulation of biological networks poses new challenges and calls for powerful integrative analysis tools. Most existing methods capable of simultaneously analyzing a large number of networks were primarily designed for unweighted networks, and cannot easily be extended to weighted networks. However, it is known that transforming weighted into unweighted networks by dichotomizing the edges of weighted networks with a threshold generally leads to information loss. We have developed a novel, tensor-based computational framework for mining recurrent heavy subgraphs in a large set of massive weighted networks. Specifically, we formulate the recurrent heavy subgraph identification problem as a heavy 3D subtensor discovery problem with sparse constraints. We describe an effective approach to solving this problem by designing a multi-stage, convex relaxation protocol, and a non-uniform edge sampling technique. We applied our method to 130 co-expression networks, and identified 11,394 recurrent heavy subgraphs, grouped into 2,810 families. We demonstrated that the identified subgraphs represent meaningful biological modules by validating against a large set of compiled biological knowledge bases. We also showed that the likelihood for a heavy subgraph to be meaningful increases significantly with its recurrence in multiple networks, highlighting the importance of the integrative approach to biological network analysis. Moreover, our approach based on weighted graphs detects many patterns that would be overlooked using unweighted graphs. In addition, we identified a large number of modules that occur predominately under specific phenotypes. This analysis resulted in a genome-wide mapping of gene network modules onto the phenome. Finally, by comparing module activities across many datasets, we discovered high-order dynamic cooperativeness in protein complex networks and transcriptional regulatory networks.

Morphological analysis of CDC2 and glycogen synthase kinase 3β phosphorylation as markers of g2 → m transition in glioma

G2 → M transition is a strategic target for glioma chemotherapy. Key players in G2 → M transition include CDC2 and glycogen synthase kinase 3β (GSK3β), which are highly regulated by posttranslational phosphorylation. This report is a morphological analysis of CDC2 and GSK3β phosphorylation using immunohistochemistry in gliomas with different biological properties. GBM showed a 2.8-fold and 5.6-fold increase in number of cells positive for pThr161CDC2 and a 4.2- and 6.9-fold increase in number of cells positive for pTyr15CDC2 relative to oligodendroglioma and ependymoma, respectively. Elevated labeling for inhibited phospho-CDC2 (pTyr15CDC) correlates with elevated levels of phosphorylated glycogen synthase kinase 3β (GSK3β). 71% of the GBM cases showed intermediate to high intensity staining for pSer9SGK3β 53% of oligodendroglioma, and 73% of ependymoma showed low intensity staining. CDC2 gene amplification correlates with increased survival in glioblastoma multiforme (GBM) and astrocytoma WHO grades II-III, but not in oligodendroglioma WHO grades II-III.

Glioma stem cells involved in tumor tissue remodeling in a xenograft model

OBJECT

Although tissue remodeling plays a crucial role in the tumorigenesis and progression of human gliomas, its mechanisms remain largely uncertain. In the current study, the authors investigated the potential role of human glioma stem cells (hGSCs) in the tissue remodeling of gliomas.

METHODS

Transgenic nude mice with ubiquitous green fluorescent protein (GFP) expression were obtained by crossing nontransgenic NC athymic nude mice with the GFP transgenic C57BL/6J mice. As a result, GFP was expressed in essentially all tissues in the offspring. Human glioma stem cells were then orthotopically implanted into the GFP nude mice in an effort to assess the hGSC-host brain interactions and thereby elucidate the roles of tissue remodeling during tumorigenesis and progression of human gliomas.

RESULTS

All of the essential tissues in the GFP transgenic nude mice, including the brain, fluoresced green under an excitation light; therefore, tumor remodeling by hGSCs can be unambiguously distinguished from a bright green background composed of adjacent host GFP-expressing components. This technique enabled the authors to address the following concerns: 1) hGSCs were involved in the invasiveness of gliomas and adjacent stroma degradation of the host. 2) An in vivo study demonstrated that cell fusion occurred between hGSCs and host cells. 3) Vasculogenic mimicry--the formation of patterned, tubular networks of vascular channels by transdifferentiated hGSCs--could be observed. 4) Differentiation mimicry--namely, the differentiation direction of hGSCs bearing multidifferentiation potentials--seemed to be decided by the local host cellular microenviroment.

CONCLUSIONS

The results of this study indicated that the GFP transgenic nude mice model with GFP expression in essentially all tissues could be obtained by crossing nontransgenic athymic nude mice with transgenic GFP mice. This model should greatly expand our knowledge of glioma-host interactions. The data indicated that hGSCs might play a decisive role in tissue remodeling of gliomas as well.

Clinical significance of cyclin B1 and cyclin-dependent kinase 1 expression in human esophageal squamous cell carcinoma

AIM: To investigate the expression of cyclin B1 and cyclin-dependent kinase 1 (CDK1) proteins in esophageal squamous cell carcinoma (ESCC) and analyze its clinicopathological significance.

METHODS: A total of 52 ESCC specimens were used in the study. Matched normal esophageal mucosal tissues were used as controls. Of all ESCC specimens, 8 had grade I disease, 20 had grade II disease, 24 had grade III disease; 20 had lymph node metastasis, 32 had no lymph node metastasis; 16 had carcinoma in situ, 36 had invasive carcinoma. The expression of cyclin B1 and CDK1 was detected by streptavidin-peroxidase (SP) immunohistochemical method. The correlation of cyclin B1 and CDK1 expression with the clinical features of ESCC was then analyzed.

RESULTS: The expression levels of cyclin B1 and CDK1 were significantly higher in ESCC tissues than in adjacent normal esophageal mucosal tissues (71.2% vs 2.0% and 65.4% vs 3.9%, respectively; both P < 0.05). The overexpression of cyclin B1 and CDK1 in ESCC tissues had no correlation with patient gender and age, but had significant correlations with histological grade, depth of invasion and lymph node metastasis (all P < 0.05). The overexpression of cyclin B1 in ESCC tissues was positively correlated with that of CDK1 (r = 0.697, P < 0.05).

CONCLUSION: Overexpression of cyclin B1 and CDK1 proteins can promote the development and progression of ESCC. There is a positive correlation between the expression of cyclin B1 and CDK1 in ESCC. Detection of cyclin B1 and CDK1 expression is useful for evaluation of the biological behavior of ESCC.

Cellular distributions of molecules with altered expression specific to thyroid proliferative lesions developing in a rat thyroid carcinogenesis model

To identify differentially regulated molecules related to early and late stages of tumor promotion in a rat two-stage thyroid carcinogenesis model by an antithyroid agent, sulfadimethoxine, microarray-based microdissected lesion-specific gene expression profiling was carried out. Proliferative lesions for profiling were divided into two categories: (i) focal follicular cell hyperplasias (FFCH) and adenomas (Ad) as early lesions; and (ii) carcinomas (Ca) as more advanced. In both cases, gene expression was compared with that in surrounding non-tumor follicular cells. Characteristically, upregulation of cell cycle-related genes in FFCH + Ad, downregulation of genes related to tumor suppression and transcription inhibitors of inhibitor of DNA binding (Id) family proteins in Ca, and upregulation of genes related to cell proliferation and tumor progression in common in FFCH + Ad and Ca, were detected. The immunohistochemical distributions of molecules included in the altered expression profiles were further examined. In parallel with microarray data, increased localization of ceruloplasmin, cyclin B1, and cell division cycle 2 homolog A, and decreased localization of poliovirus receptor-related 3 and Id3 were observed in all types of lesion. Although inconsistent with the microarray data, thyroglobulin immunoreactivity appeared to reduce in Ca. The results thus suggest cell cycling facilitation by induction of M-phase-promoting factor consisting of cyclin B1 and cell division cycle 2 homolog A and generation of oxidative responses as evidenced by ceruloplasmin accumulation from an early stage, as well as suppression of cell adhesion involving poliovirus receptor-related 3 and inhibition of cellular differentiation regulated by Id3. Decrease of thyroglobulin in Ca may reflect dedifferentiation with progression.