Anchoring super-enhancer-driven oncogenic lncRNAs for anti-tumor therapy in hepatocellular carcinoma.

Super-enhancer (SE) plays a vital role in the determination of cell identity and fate. Up-regulated expression of coding genes is frequently associated with SE. However, the transcription dysregulation driven by SE, from the viewpoint of long non-coding RNA (lncRNA), remains unclear. Here, SE-associated lncRNAs in HCC are comprehensively outlined for the first time. This study integrally screens and identifies several novel SE-associated lncRNAs that are highly abundant and sensitive to JQ1. Especially, HSAL3 is identified as an uncharacterized SE-driven oncogenic lncRNA, which is activated by transcription factors HCFC1 and HSF1 via its super-enhancer. HSAL3 interference negatively regulates NOTCH signaling, implying the potential mechanism of its tumor-promoting role. The expression of HSAL3 is increased in HCC samples, and higher HSAL3 expression indicates an inferior overall survival of HCC patients. Furthermore, siHSAL3 loaded nanoparticles exert anti-tumor effect on HCC in vitro and in vivo. In conclusion, this is the first comprehensive survey of SE-associated lncRNAs in HCC. HSAL3 is a novel SE-driven oncogenic lncRNA, and siHSAL3 loaded nanoparticles are therapeutic candidates for HCC. This work sheds lights on the merit of anchoring SE-driven oncogenic lncRNAs for HCC treatment.

Isocitrate dehydrogenase 1-snail axis dysfunction significantly correlates with breast cancer prognosis and regulates cell invasion ability.

BACKGROUND: The isocitrate dehydrogenase (IDH) gene family expresses key functional metabolic enzymes in the Krebs cycle and mediates the epigenetic reprogramming, which serves as an important biomarker of breast cancer. However, the expression levels of the IDH protein and their biological function in human breast cancer remain largely unknown. METHODS: In this study, the clinical impact of IDH1 expression on the progression and prognosis of breast cancer was evaluated using immunohistochemistry assay (IHC) of the corresponding tumor-adjacent normal, ductal carcinoma in situ (DCIS), and invasive ductal carcinoma (IDC) tissues from 309 patients with breast ductal carcinoma. The relationship between microRNA (miRNA) and IDH1 were examined by a bioinformatics approach, western blot and reporter assay. The biological functions of IDH1 were examined in breast cancer cells with IDH1 knockdown, including proliferation, migration and invasion. RESULTS: The present findings revealed that the mRNA and protein expression levels of IDH1 were both significantly lower in breast cancer tissues than in adjacent normal tissues. A low expression level of IDH1 in breast cancer significantly correlated with advanced stage (p = 0.012), lymph node metastasis (p = 0.018), and poor disease-specific survival (DSS) (adjusted hazard ratio (AHR), 1.57, 95% confidence interval (CI), 1.08-2.30; p = 0.02). Furthermore, oncogenic miR-32 and miR-92b were identified to suppress IDH1 expression, leading to the inhibition of cell migration and invasion. We further explored whether reduced expression of IDH1 significantly increases snail expression by activating HIFα (hypoxia-inducible factor-1 alpha) and NFκB (nuclear factor kappa B) signaling. Multivariate Cox regression analysis revealed that the combination of low IDH1 and high snail expression could be an independent risk factor for shorter DSS (AHR, 2.34; 95% CI, 1.32-4.16; p = 0.004) and shorter disease-free survival (AHR, 2.50; 95% CI, 1.39-4.50; p = 0.002) in patients with breast cancer. CONCLUSION: Our findings revealed that a IDH1low/Snailhigh molecular signature could serve as an independent biomarker for poor prognosis in breast cancer.

LncRNAs: key players and novel insights into cervical cancer.

Cervical cancer contributed the second highest number of deaths in female cancers, exceeded only by breast cancer, carrying high risks of morbidity and mortality. There was a great need and urgency in searching novel treatment targets and prognosis biomarkers to improve the survival rate of cervical cancer patients. Many long non-coding RNAs (lncRNAs) were emerging as pivotal regulators in various biological processes and took vitally an effect on the oncogenesis and progression of cervical cancer. In this review, we summarized the origin and overview function of lncRNAs; highlighted the roles of lncRNAs in cervical cancer in terms of prognosis and tumor progression, invasion and metastasis, apoptosis, and radio-resistance; and outlined the molecular mechanisms of lncRNAs in cervical cancer from the aspects of the interaction of lncRNAs with proteins/mRNAs (especially in HPV protein) and miRNAs, as well as RNA N-methyladenosine (m6A) methylation of lncRNAs. Meanwhile, the application of lncRNAs as biomarkers in cervical cancer prognosis and predictors for metastasis was also discussed. An overview of these researches will be valuable for broadening horizons into mechanisms, selection of meritorious biomarkers for diagnosis as well as prognosis, and future targeted therapy of cervical cancer.

Global DNA hypomethylation is associated with the development and poor prognosis of tongue squamous cell carcinoma.

BACKGROUNDS: Oral cancer is the 4th leading cause of cancer death for males and the top cancer in young adult males in Taiwan. Tongue squamous cell carcinoma (TSCC) is a common oral cancer and generally associated with poor prognosis. Global DNA hypomethylation at the 5 position of cytosine (5mC) is a well-known epigenetic feature of cancer. Therefore, the purpose of this study was to investigate the relationship of the global 5mC content with the tumorigenesis and prognosis of patients with TSCC. METHODS: The levels of global 5mC were evaluated by immunohistochemistry using tissue microarray slides of 248 surgically resected TSCC and 202 corresponding tumor adjacent normal (TAN) tissues. RESULTS: We found that the level of 5mC in TSCC (P < 0.001) was significantly decreased as compared to TAN. Among TSCC tissues, decreased levels of 5mC were associated with female gender (P = 0.036). In addition, the global hypomethylation was associated with the poor disease-specific survival in TSCC patients (adjusted hazard ratio: 1.55, P = 0.043), especially for patients in older age group (> 50 years, P = 0.013), with moderate or poor cell differentiation (P = 0.044), early stage of disease (I-II, P = 0.046), small tumor size (T1-T2, P = 0.005), without lymph node involvement (P = 0.041), and ever received postoperative radiotherapy (P = 0.009). CONCLUSIONS: Global hypomethylation was an independent biomarker for the development and poor prognosis of TSCC.

Polymerization under Hypersaline Conditions: A Robust Route to Phenolic Polymer-Derived Carbon Aerogels.

Polymer-derived carbon aerogels can be obtained by direct polymerization of monomers under hypersaline conditions using inorganic salts. This allows for significantly increased mechanical robustness and avoiding special drying processes. This concept was realized by conducting the polymerization of phenol-formaldehyde (PF) in the presence of ZnCl2 salt. Afterwards, the simultaneous carbonization and foaming process conveniently converts the PF monolith into a foam-like carbon aerogel. ZnCl2 plays a key role, serving as dehydration agent, foaming agent, and porogen. The carbon aerogels thus obtained are of very low density (25 mg cm-3 ), high specific surface area (1340 m2 g-1 ), and have a large micro- and mesopore volume (0.75 cm3 g-1 ). The carbon aerogels show very promising potential in the separation/extraction of organic pollutants and for energy storage.

Reduction of global 5-hydroxymethylcytosine is a poor prognostic factor in breast cancer patients, especially for an ER/PR-negative subtype.

DNA methylation at the 5 position of cytosine (5 mC) is an epigenetic hallmark in cancer. The 5 mC can be converted to 5-hydroxymethylcytosine (5 hmC) through a ten-eleven-translocation (TET). We investigated the impact of 5 mC, 5 hmC, TET1, and TET2 on tumorigenesis and prognosis of breast cancer. Immunohistochemistry was used to assess the levels of 5 mC, 5 hmC, TET1, and TET2 in the corresponding tumor adjacent normal (n = 309), ductal carcinoma in situ (DCIS, n = 120), and invasive ductal carcinoma (IDC, n = 309) tissues for 309 breast ductal carcinoma patients. 5 mC, 5 hmC, TET1-n, and TET2-n were significantly decreased during DCIS and IDC progression. In IDC, the decrease of 5 hmC was correlated with the cytoplasmic mislocalization of TET1 (p < 0.001) as well as poor disease-specific survival (DSS) (adjusted hazard ratio [AHR] 1.95, p = 0.003) and disease-free survival (DFS) (AHR 1.91, p = 0.006). The combined decrease of 5 mC and 5 hmC was correlated with worse DSS (AHR 2.19, p = 0.008) and DFS (AHR 1.99, p = 0.036). Stratification analysis revealed that the low level of 5 mC was associated with poor DSS (AHR 1.89, p = 0.044) and DFS (AHR 2.02, p = 0.035) for the ER/PR-positive subtype. Conversely, the low level of 5 hmC was associated with worse DSS (AHR 2.77, p = 0.002) and DFS (AHR 2.69, p = 0.006) for the ER/PR-negative subtype. The decreases of 5 mC, 5 hmC, TET1-n, and TET2-n were biomarkers of tumor development. The global reduction of 5 hmC was a poor prognostic factor for IDC, especially for ER/PR-negative subtype.

Human anti-EGFL7 recombinant full-length antibodies selected from a mammalian cell-based antibody display library.

Epidermal growth factor-like domain 7 (EGFL7) has been implicated in promoting solid tumor growth and metastasis via stimulating tumor-associated angiogenesis. The advent of antibody display technology (phage, bacteria, and yeast) led to an enormous revival in the use of antibodies as diagnostic and therapeutic tools for fighting cancer. However, problems with protein folding, posttranslational modification, and codon usage still limit the number of improved antibodies that can be obtained. We describe here the isolation of an EGFL7-specific antibody from a mammalian cell-based full-length antibody display library generated from peripheral blood mononuclear cells of patients with hepatocellular carcinoma. Using a novel vector, contained glycosylphosphatidylinositol anchor and restriction enzyme sites NheI and ClaI, antibody libraries are displayed as whole IgG molecules on the cell surface and screened for specific antigen binding by a combination of magnetic beads and measured by cell ELISA. Anti-EGFL7 antibody was successfully isolated from the library. The mammalian cell-based full-length antibody display library is a great potential application for rapid identification and cloning of human mAbs of targeting hepatocellular carcinoma.

Construction and development of a mammalian cell-based full-length antibody display library for targeting hepatocellular carcinoma.

We present a detailed method for constructing a mammalian cell-based full-length antibody display library for targeting hepatocellular carcinoma. Two novel mammalian library vectors pcDNA3-CHm and pcDNA3-CLm were constructed that contained restriction enzyme sites NheI, ClaI and antibody constant domain. Mammalian expression vector pcDNA3-CHm contains IgG heavy-chain (HC) constant region and glycosylphosphatidylinositol anchor (GPI) that could be anchored full-length antibodies on the surface of mammalian cells. GOLPH2 prokaryotic expression vector was carried out in Escherichia coli and purified by immobilized metal affinity chromatography. Variable domain of heavy-chain and variable domain of light-chain genes were respectively inserted into the vector pcDNA3-CHm and pcDNA3-CLm by ligation, and antibody libraries are displayed as whole IgG molecules on the cell surface by co-transfecting this HC-GPI with a light chain. By screening the cell library using magnetic beads and cell ELISA, the cell clone that displayed GOLPH2-specific antibodies on cell surfaces was identified. The mammalian cell-based antibody display library is a great potential application for displaying full-length functional antibodies of targeting hepatocellular carcinoma on the surface of mammalian cells. Anti-GOLPH2 display antibody was successfully isolated from the library.

eccDNAdb: a database of extrachromosomal circular DNA profiles in human cancers.

Extrachromosomal circular DNA (eccDNA) elements are circular DNA molecules that are derived from but are independent of chromosomal DNA. EccDNA is emerging as a rising star because of its ubiquitous existence in cancers and its crucial role in oncogene amplification and tumor progression. In the present study, whole-genome sequencing (WGS) data of cancer samples were downloaded from public repositories. Afterwards, eccDNAs were identified from WGS data via bioinformatic analyses. To leverage database coverage, eccDNAs were also collected by manual curation of literatures. Gene expression and clinical data were downloaded from TCGA and CCLE and then used to investigate the roles of eccDNAs in cancers. Finally, the first integrated database of eccDNAs, eccDNAdb, was developed. eccDNAdb currently includes 1270 eccDNAs, which were identified in 480 samples (of 42 cancers) after analyzing a total number of 3395 tumor samples (of 57 cancers) including patient tissues, patient-derived xenografts, and cancer cell lines. A total number of 54,901 eccDNA genes were annotated and included in the database as well. With the integration of gene expression, clinical information and chromatin accessibility data, eccDNAdb enables users to easily determine the biological function and clinical relevance of eccDNAs in human cancers. In conclusion, eccDNAdb is freely accessible at http://www.eccdnadb.org . To our knowledge, eccDNAdb is the first database in the eccDNA research field. It is expected to provide insight for novel cancer therapies.

Upregulation of Superenhancer-Driven LncRNA FASRL by USF1 Promotes De Novo Fatty Acid Biosynthesis to Exacerbate Hepatocellular Carcinoma.

Superenhancers drive abnormal gene expression in tumors and promote malignancy. However, the relationship between superenhancer-associated long noncoding RNA (lncRNA) and abnormal metabolism is unknown. This study identifies a novel lncRNA, fatty acid synthesis-related lncRNA (FASRL), whose expression is driven by upstream stimulatory factor 1 (USF1) through its superenhancer. FASRL promotes hepatocellular carcinoma (HCC) cell proliferation in vitro and in vivo. Furthermore, FASRL binds to acetyl-CoA carboxylase 1 (ACACA), a fatty acid synthesis rate-limiting enzyme, increasing fatty acid synthesis via the fatty acid metabolism pathway. Moreover, the expression of FASRL, USF1, and ACACA is increased, and their high expression indicates a worse prognosis in HCC patients. In summary, USF1 drives FASRL transcription via a superenhancer. FASRL binding to ACACA increases fatty acid synthesis and lipid accumulation to mechanistically exacerbate HCC. FASRL may serve as a novel prognostic marker and treatment target in HCC.

Spaceflight alters the gene expression profile of cervical cancer cells.

Our previous study revealed that spaceflight induced biological changes in human cervical carcinoma Caski cells. Here, we report that 48A9 cells, which were subcloned from Caski cells, experienced significant growth suppression and exhibited low tumorigenic ability after spaceflight. To further understand the potential mechanism at the transcriptional level, we compared gene expression between 48A9 cells and ground control Caski cells with suppression subtractive hybridization (SSH) and reverse Northern blotting methods, and analyzed the relative gene network and molecular functions with the Ingenuity Pathways Analysis (IPA) program. We found 5 genes, SUB1, SGEF, MALAT-1, MYL6, and MT-CO2, to be up-regulated and identified 3 new cDNAs, termed B4, B5, and C4, in 48A9 cells. In addition, we also identified the two most significant gene networks to indicate the function of these genes using the IPA program. To our knowledge, our results show for the first time that spaceflight can reduce the growth of tumor cells, and we also provide a new model for oncogenesis study.

Mapping gene associations in human mitochondria using clinical disease phenotypes.

Nuclear genes encode most mitochondrial proteins, and their mutations cause diverse and debilitating clinical disorders. To date, 1,200 of these mitochondrial genes have been recorded, while no standardized catalog exists of the associated clinical phenotypes. Such a catalog would be useful to develop methods to analyze human phenotypic data, to determine genotype-phenotype relations among many genes and diseases, and to support the clinical diagnosis of mitochondrial disorders. Here we establish a clinical phenotype catalog of 174 mitochondrial disease genes and study associations of diseases and genes. Phenotypic features such as clinical signs and symptoms were manually annotated from full-text medical articles and classified based on the hierarchical MeSH ontology. This classification of phenotypic features of each gene allowed for the comparison of diseases between different genes. In turn, we were then able to measure the phenotypic associations of disease genes for which we calculated a quantitative value that is based on their shared phenotypic features. The results showed that genes sharing more similar phenotypes have a stronger tendency for functional interactions, proving the usefulness of phenotype similarity values in disease gene network analysis. We then constructed a functional network of mitochondrial genes and discovered a higher connectivity for non-disease than for disease genes, and a tendency of disease genes to interact with each other. Utilizing these differences, we propose 168 candidate genes that resemble the characteristic interaction patterns of mitochondrial disease genes. Through their network associations, the candidates are further prioritized for the study of specific disorders such as optic neuropathies and Parkinson disease. Most mitochondrial disease phenotypes involve several clinical categories including neurologic, metabolic, and gastrointestinal disorders, which might indicate the effects of gene defects within the mitochondrial system. The accompanying knowledgebase (http://www.mitophenome.org/) supports the study of clinical diseases and associated genes.

Autoantibodies as potential biomarkers for nasopharyngeal carcinoma.

Autoantibody signatures, as new biomarkers, may improve the early detection of nasopharyngeal carcinoma (NPC). We constructed a T7 phage cDNA library from mixed NPC tissues, and we isolated 31 tumor-associated proteins using biopan enrichment techniques with sera from NPC patients and from healthy population. DNA sequence analysis showed that among 31 phage-displayed proteins, 22 have sequence identity with known or putative tumor-associated proteins. The results of immunochemical reactivity of patients' sera with phage-expressed proteins showed enrichment in the number of immunogenic phage clones in the biopanning process and also confirmed that antibodies were present in the sera of patients but not in the sera of healthy donors. The autoantibody against phage-expressed protein MAGE, HSP70, Fibronectin, and CD44 measured by ELISA had greater predictive value than that against EBNA-1, respectively. The antibody levels against MAGE in sera positively correlated with the clinical stages of NPC, and the antibody levels against other three proteins partly correlated with the clinical stages of NPC. Our studies suggested that the autoantibodies against tumor-associated antigens in the sera of NPC patients could be used as a screening test for NPC. Studies of the corresponding proteins may have significances in tumor biology, novel drug development, and immunotherapy.

Colorectal carcinoma-associated antigen Ca-Hb3 detected by one-dimensional SDS-polyacrylamide gel electrophoresis and liquid chromatography-tandem mass spectrometry.

AIM: To comprehensively identify the proteins of tumor relative antigen Ca-Hb3 recognized by colorectal carcinoma monoclonal antibody Hb3. METHODS: Ca-Hb3 was isolated by SDS-polyacrylamide gel electrophoresis (PAGE) followed by digestion with trypsin. Trypsin peptides were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The proteins identified by mass spectrometry were analyzed using bioinformatics. RESULTS: Ca-Hb3 was identified as a CKAP4-like protein by Nano HPLC tandem mass spectrometry analysis. The molecular weight of CKAP4-like protein was 62.02 kDa, including one hydrophobic region, one transmembrane domain, five coiled coils, four glycosylation sites and forty-nine phosphorylation sites. CKAP4-like protein had a high homogeneity with DeltaNp63alpha. The characteristic expression of DeltaNp63alpha that is considered a potential oncogene in the isoforms of p63 was similar to that of Ca-Hb3. CONCLUSION: Ca-Hb3 is probably a CKAP4-like protein, belonging to DeltaNp63alpha isoform of p63 family.

Gamma-aminobutyric acid promotes human hepatocellular carcinoma growth through overexpressed gamma-aminobutyric acid A receptor alpha 3 subunit.

AIM: To investigate the expression pattern of gamma-aminobutyric acid A (GABAA) receptors in hepatocellular carcinoma (HCC) and indicate the relationship among gamma-aminobutyric acid (GABA), gamma-aminobutyric acid A receptor alpha3 subunit (GABRA3) and HCC. METHODS: HCC cell line Chang, HepG2, normal liver cell line L-02 and 8 samples of HCC tissues and paired non-cancerous tissues were analyzed with semiquantitative polymerase chain reaction (PCR) for the expression of GABAA receptors. HepG2 cells were treated with gamma-aminobutyric acid (GABA) at serial concentrations (0, 1, 10, 20, 40 and 60 micromol/L), and their proliferating abilities were analyzed with the 3-(4, 5-methylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, cell doubling time test, colon formation assay, cell cycle analysis and tumor planted in nude mice. Small interfering RNA was used for knocking down the endogenous GABRA3 in HepG2. Proliferating abilities of these cells treated with or without GABA were analyzed. RESULTS: We identified the overexpression of GABRA3 in HCC cells. Knockdown of endogenous GABRA3 expression in HepG2 attenuated HCC cell growth, suggesting its role in HCC cell viability. We determined the in vitro and in vivo effect of GABA in the proliferation of GABRA3-positive cell lines, and found that GABA increased HCC growth in a dose-dependent manner. Notably, the addition of GABA into the cell culture medium promoted the proliferation of GABRA3-expressing HepG2 cells, but not GABRA3-knockdown HepG2 cells. This means that GABA stimulates HepG2 cell growth through GABRA3. CONCLUSION: GABA and GABRA3 play important roles in HCC development and progression and can be a promising molecular target for the development of new diagnostic and therapeutic strategies for HCC.

[Construction of eukaryotic expression vector encoding human nasopharyngeal carcinoma anti-idiotype antibody single chain fragment gene G22 and its expression].

OBJECTIVE: To construct a eukaryotic expression vector encoding human nasopharyngeal carcinoma anti-idiotype antibody single chain fragment (ScFv) gene G22, and to identify its expression in rectal cancer cells (CMT-93). METHODS: The G22 gene was ligated into the sites of EcoRI and NotI of eukaryotic expression vector pcDNA3.1(+). After the identification and DNA sequencing, the recombinant plasmid pc DNA3.1(+)-G22 was stably transfected into CMT-93 cells, and the expression of G22 was detected by Western blot, flow cytometry and immunofluorescence staining. RESULTS: Restriction enzyme digestion and DNA sequencing showed that the recombinant plasmid contained the human nasopharyngeal carcinoma anti-idiotype antibody ScFv gene G22. Transfection experiment verified that G22 gene could be expressed in CMT-93 cells in the right way. CONCLUSION: The eukaryotic expression vector containing the human nasopharyngeal carcinoma anti-idiotype antibody ScFv gene G22 is successfully constructed and expressed, which is the basis for further study of its DNA vaccine.

[Detection of autoantibodies in the sera of nasopharyngeal carcinoma patients].

OBJECTIVE: To investigate whether there are autoantibodies to nasopharyngeal carcinoma (NPC) in the sera of patients and to find new NPC biomarkers. METHODS: Cell plate of Epstein Barr virus negative NPC cell line CNE1 was prepared, and difference between 32 NPC patient sera and 54 normal sera was analyzed by ELISA. We extracted the total protein of CNE1, and analyzed whether there were specific proteins to react with NPC sera by Western blot. RESULTS: The average absorbance values of serum antibody in NPC patients (0.904+/-0.032) were significantly higher than those of normal serum antibody absorbance values (0.736+/-0.028) (P< 0.01). The analysis with Western blot showed there were positive bands,and some of these were unanimous bands, but the intensity increased, and some of these were new bands compared with the normal sera. These positive bands may be NPC tumor-associated antigens or NPC tumor-specific antigens. CONCLUSION: Autoantibodies that react with NPC exist in the sera of NPC patients, but they do not react with Epstein-Barr virus. It provides the basis to seek the tumor biomarkers in NPC sera.

The emergence of long non-coding RNAs in hepatocellular carcinoma: an update.

Hepatocellular carcinoma (HCC) accounting for roughly 90% of all primary liver neoplasms is the sixth most frequent neoplasm and the second prominent reason of tumor fatality worldwide. As regulators of diverse biological processes, long non-coding RNAs (lncRNAs) are involved in onset and development of neoplasms. With the continuous booming of well-featured lncRNAs in HCC from 2016 to now, we reviewed the newly-presented comprehension about the relationship between lncRNAs and HCC in this study. To be specific, we summarized the overview function and study tools of lncRNAs, elaborated the roles of lncRNAs in HCC, and sketched the molecule mechanisms of lncRNAs in HCC. In addition, the application of lncRNAs serving as biomarkers in early diagnosis and outcome prediction of HCC patients was highlighted.

Ten-eleven translocation 1 dysfunction reduces 5-hydroxymethylcytosine expression levels in gastric cancer cells.

A sixth base, 5-hydroxymethylcytosine (5hmC), is formed by the oxidation of 5-methylcytosine (5mC) via the catalysis of the ten-eleven translocation (TET) protein family in cells. Expression levels of 5hmC are frequently depleted during carcinogenesis. However, the detailed mechanisms underlying the depletion of 5hmC expression in gastric cancer cells remains unclear, and further research is required. The present study examined the expression levels of 5mC and 5hmC and the expression levels of TET1 and TET2 in gastric cancer tissues using immunohistochemistry. The results revealed that 5hmC expression levels were markedly lower in gastric cancer tissues compared with corresponding adjacent normal tissues. Furthermore, a decrease in 5hmC expression levels was associated with a decrease in TET1 protein expression levels in gastric cancer tissues. The ectopic expression level of TET1 may increase the 5hmC expression level in gastric cancer cells. In addition, the results revealed that TET1 protein expression was markedly different in regards to subcellular localization, and mislocalization was significantly associated with the depletion of 5hmC expression levels in gastric cancer. Together, the results of the present study indicated that TET1 dysfunction reduces 5hmC expression levels, and this phenomenon may serve a crucial role in gastric cancer progression.

[Biological properties of Caski cell lines induced by exposing to the space environment].

OBJECTIVE: To investigate the biological properties of Caski cell lines induced by exposing to the space environment. METHODS: Caski cells were carried in "Shen Zhou IV" airship. After 7 days of spaceflight, cells survived and were monocoloned, and the experimental methods such as cell morphological observation, the cell proliferation assay, flow cytometry cell cycle analysis, the soft agar assay, and tumorigenesis assay were used to analyze cell growth characteristics and malignant phenotypes. RESULTS: Altogether 1440 strains subclonal cell lines were established and 4 strains were screened. Compared with the control group, mutated cells appeared to have multiple cell morphological changes. Strains numbered 44F10 and 17E3 were screened due to their increased cell proliferation and tumorigenesis, and their cell cycles were induced to progress from G(1) to S phase, while strains 48A9 and 31F2 were opposite to 44F10 and 17E3 in cytological events. The average population double time of ground nomal control group, ground simulant control group, strains numbered 44F10, 17E3, 48A9 and 31F2 groups were 56.54, 58.44, 52.96, 51.46, 101.76 and 88.47h, respectively; compared with the control group, the average double time of strains numbered 44F10 and 17E3 was decline, but with no statistical significance. However, compared with the control groups, the average double time of 48A9 and 31F2 was significant increased (P<0.05). The colony formation rates were 9.7%, 9.3%, 14.7%, 12.1%, 0 and 0.1%, respectively, and the difference between the ground control groups and the other groups was significant (P<0.01); 6 groups of above-mentioned Caski cells were inoculated subcutaneously in Babl/c nude mice respectively. Forty-seven days later, the formed tumors in the nude mice were statistically analyzed and tested. The average weight of tumors of the above-mentioned groups was 0.066, 0.066, 0.175, 0.249, 0.011 and 0.018g. The difference between the ground control groups and other groups was significant (P<0.05). CONCLUSION: Spaceflight may affect the physiological characteristics of tumor cells and the variation is complicated.