LINC00313 facilitates osteosarcoma carcinogenesis and metastasis through enhancing EZH2 mRNA stability and EZH2-mediated silence of PTEN expression.

BACKGROUND: Osteosarcoma is one of the five leading causes of cancer death among all pediatric malignancies. Recent advances in non-coding RNAs suggested that many long noncoding RNAs (lncRNAs) are dysregulated in cancer tissues and play important roles in carcinogenesis. We aimed to further explore the mechanisms of Long Intergenic Non-Protein Coding RNA 313 (LINC00313)-promoted malignant phenotypes of osteosarcoma. METHODS: The mRNA expressions were determined by quantitative real-time PCR. Protein levels were detected using Western blotting or immunohistochemistry staining. Protein binding to genomic DNA and RNA were measured using chromatin and RNA immunoprecipitation assay, respectively. CCK-8 and EdU incorporation assay were adopted to detect cell proliferation. Transwell assay was employed to assess the capacity of cell migration and invasion. The roles of LINC00313 and its target genes in tumorigenesis and metastasis of osteosarcoma were evaluated using subcutaneous xenograft models and tail vein inoculation models. RESULTS: LINC00313 was elevated in osteosarcoma tissues compared with adjacent normal tissues. Higher LINC00313 was associated with advanced grades of osteosarcoma. LINC00313 promoted cell proliferation, migration, invasion in vitro and tumor growth as well as metastasis in vivo through inhibiting PTEN expression to promote AKT phosphorylation. Mechanistically, LINC00313 favored the interaction between FUS and EZH2, leading to the prolonged half-life of EZH2 mRNA, thereby in turn up-regulating EZH2 proteins and increasing EZH2-mediated epigenetic silence of PTEN. CONCLUSION: LINC00313 exerted oncogene-like actions through increasing EZH2 mRNA stability, leading to PTEN deficiency in osteosarcoma.

Anticancer activity of Fisetin against the human osteosarcoma cell lines involves G2/M cell cycle arrest, mitochondrial apoptosis and inhibition of cell migration and invasion.

Retraction of: 'Anticancer activity of Fisetin against the human osteosarcoma cell lines involves G2/M cell cycle arrest, mitochondrial apoptosis and inhibition of cell migration and invasion', by Chunyang Xing, Yuzhu Zhang, Rong Su, Ronghuan Wu JBUON 2019;25(2):1022-1027; PMID:32521901. Following the publication of the above article, readers drew to our attention that part of the data was unreliable. The authors were requested to provide the raw data to prove the originality, but were unable to do so. After an investigation, the Editors of JBUON decided to retract this article. We thank the readers for bringing this matter to our attention. We apologize for any inconvenience it may cause.

Anticancer activity of Fisetin against the human osteosarcoma cell lines involves G2/M cell cycle arrest, mitochondrial apoptosis and inhibition of cell migration and invasion.

PURPOSE: Osteosarcoma is rare but fatal type of human malignancy. The high metastasis rate, late diagnosis, emergence of drug resistance against drugs such as doxorubicin, and the lack of therapeutic targets obstructs the treatment of osteosarcoma. The present investigation explores the anticancer properties of Fisetin against human osteosarcoma cells. METHODS: The cell viability was determined by WST-1 assay. DAPI and Annexin V/propidium iodide (PI) assays were used for detection of apoptosis. Flow cytometry was used for the determination of osteosarcoma MG-63 cell distribution. Wound healing and transwell assays were used for cell migration and invasion. Western blotting was used for protein expression analysis. RESULTS: The results showed that Fisetin inhibits the growth of the MG-63 cells in a dose-dependent manner. Fisetin showed an IC50 of 18 µM against the MG-63 cells. The growth inhibitory effects of Fisetin were mainly due to induction of apoptosis which was accompanied by enhancement of the capsase-3 and Bax and depletion of Bcl-2 expression. Fisetin treatment increased reactive oxygen species (ROS) from 100 in untreated to 220% at 36 µM and decreased mitochondrial membrane potential (MMP) levels from 100 in untreated to 21% at 36 µM. Fisetin also induced G2/M cell cycle arrest of the MG-63 cells and suppressed the expression of cyclin-B1. The wound healing and the transwell assay showed that Fisetin suppressed the migration and invasion of the MG-63 cells. CONCLUSION: Taken together, Fisetin may find use as lead molecule in the osteosarcoma therapeutic development programmes.

Long non-coding RNA SNHG3 accelerates progression in glioma by modulating miR-384/HDGF axis.

Glioma is a malignant primary brain tumor that occurs in the central nervous system and has threatened the well-being of millions of patients. It is well acknowledged that long non-coding RNA (lncRNA) SNHG3 participates in the regulation of proliferation, inflation, differentiation, and metastasis in many cancers. However, the regulatory effect of SNHG3 on glioma progression is still controversial. The expression of SNHG3 and HDGF was upregulated, whereas miR-384 was downregulated in glioma tissues, compared with the normal tissues. Interestingly, high SNHG3 contributed to low survival rate while low SNHG3 showed the opposite result. Moreover, SNHG3 or HDGF knockdown significantly suppressed proliferation, migration, and invasion and induced apoptosis in glioma. Meanwhile, restoration of HDGF abrogated the inhibition of SNHG3 silencing on glioma cell progression. Besides, miR-384 inhibitor attenuated SNHG3 silencing induced inhibition on HDGF mRNA and protein expression in A172 and SHG44 cells. LncRNA SNHG3 promotes cell proliferation, migration, and invasion in glioma by enhancing HDGF expression via miR-384 sponging, representing the promising targets for the development of novel therapeutic strategies.

Correction to: PHF8 upregulation contributes to autophagic degradation of E-cadherin, epithelial-mesenchymal transition and metastasis in hepatocellular carcinoma.

In the publication of our publication [1], we have noticed there is a wrong label in Fig. 1e, in which the position of "HCC" and "Adjacent" should be transposed.

Correction to: PHF8 upregulation contributes to autophagic degradation of E-cadherin, epithelial-mesenchymal transition and metastasis in hepatocellular carcinoma.

In the publication of this article [1], there are two inadvertent errors.

PHF8 upregulation contributes to autophagic degradation of E-cadherin, epithelial-mesenchymal transition and metastasis in hepatocellular carcinoma.

BACKGROUND: Plant homeodomain finger protein 8 (PHF8) serves an activator of epithelial-mesenchymal transition (EMT) and is implicated in various tumors. However, little is known about PHF8 roles in hepatocellular carcinoma (HCC) and regulating E-cadherin expression. METHODS: PHF8 expression pattern was investigated by informatic analysis and verified by RT-qPCR and immunochemistry in HCC tissues and cell lines. CCK8, xenograft tumor model, transwell assay, and tandem mCherry-GFP-LC3 fusion protein assay were utilized to assess the effects of PHF8 on proliferation, metastasis and autophagy of HCC cells in vitro and in vivo. ChIP, immunoblot analysis, rescue experiments and inhibitor treatment were used to clarify the mechanism by which PHF8 facilitated EMT, metastasis and autophagy. RESULTS: PHF8 upregulation was quite prevalent in HCC tissues and closely correlated with worse overall survival and disease-relapse free survival. Furthermore, PHF8-knockdown dramatically suppressed cell growth, migration, invasion and autophagy, and the expression of SNAI1, VIM, N-cadherin and FIP200, and increased E-cadherin level, while PHF8-overexpression led to the opposite results. Additionally, FIP200 augmentation reversed the inhibited effects of PHF8-siliencing on tumor migration, invasion and autophagy. Mechanistically, PHF8 was involved in transcriptionally regulating the expression of SNAI1, VIM and FIP200, rather than N-cadherin and E-cadherin. Noticeably, E-cadherin degradation could be accelerated by PHF8-mediated FIP200-dependent autophagy, a crucial pathway complementary to transcriptional repression of E-cadherin by SNAI1 activation. CONCLUSION: These findings suggested that PHF8 played an oncogenic role in facilitating FIP200-dependent autophagic degradation of E-cadherin, EMT and metastasis in HCC. PHF8 might be a promising target for prevention, treatment and prognostic prediction of HCC.

Apoptotic effect of pyrroloquinoline quinone on chondrosarcoma cells through activation of the mitochondrial caspase­dependent and caspase­independent pathways.

Chondrosarcomas are malignant tumors of the bone that exhibit resistance to chemotherapy and radiation. Pyrroloquinoline quinone (PQQ) is a bacterial redox co­factor and antioxidant that has been found to induce apoptosis in various cancer cells. This study investigated the role of PQQ in cell apoptosis of chondrosarcoma cells and the underlying pathways involved. We confirmed that PQQ was cytotoxic to chondrosarcoma SW1353 cells by a cell cytotoxicity assay. Furthermore, flow cytometry showed that the number of apoptotic cells increased in a concentration­dependent and time­dependent manner following PQQ treatment, but this effect was not significant in normal cells. Co­immunoprecipitation assays showed that the binding of Smac to X­linked inhibitor­of­apoptosis protein (XIAP) was significantly increased and the binding of XIAP with caspase­3 was significantly decreased following PQQ treatment. This was accompanied by a decrease in the levels of caspase­1 and procaspase­3, as demonstrated by western blot analysis. Western blotting also showed that the level of cytochrome c in the mitochondria was decreased and its level in the cytoplasm was increased. These findings indicate the role of caspase­dependent apoptotic pathways in the effect of PQQ. Furthermore, the cytoplasmic and nuclear levels of apoptosis­inducing factor (AIF) were increased and its mitochondrial levels were decreased, and similar results were obtained for endonuclease G. Thus, the role of caspase­independent pathways was also demonstrated. Finally, in vivo tumor implantation experiments showed that PQQ was able to inhibit tumor growth in mice with chondrosarcoma. These findings demonstrated that PQQ induced apoptosis in human chondrosarcoma cells by activating mitochondrial caspase­dependent and caspase­independent pathways. Thus, the proteins involved in these pathways may have potential as antitumor treatment targets for chondrosarcoma.

The neutrophil lymphocyte ratio is associated with breast cancer prognosis: an updated systematic review and meta-analysis.

Breast cancer (BC) is the most common female malignancy within the spectrum of human cancer. One promising way to reduce the mortality and morbidity of BC is to explore novel diagnostic markers for early diagnosis and prognostication. The neutrophil lymphocyte ratio (NLR) is a good reflection of inflammation, which plays an important role in tumor progression and metastasis. However, the association between NLR and BC prognosis remains unclear. The aim of this meta-analysis is to explore the prognostic value of NLR in BC. Among the screened references in the database, 12 eligible studies were identified in this study. Patients with a higher NLR had a shorter disease-free survival (hazard ratio =1.46, 95% confidence interval: 1.12-1.90, P=0.044) and overall survival (hazard ratio =2.03, 95% confidence interval: 1.41-2.93, P<0.001). In the subgroup analysis of NLR and disease-free survival, the studies from Eastern countries had a positive result with perfect homogeneity (I (2)=0); however, this homogeneity has not been achieved in studies from Western countries. In the subgroup analysis of the NLR and overall survival, the results of the univariate and multivariate analyses were completely different, with different heterogeneity. In the luminal A and luminal B subtypes, we found that there was no association between the NLR and overall survival in the BC patients. Positive results were obtained in the analyses of the human epidermal growth factor receptor 2 (HER2)-positive and triple-negative BC subtypes. In conclusion, this meta-analysis suggests that NLR is a good prognostic marker for BC, and patients with a higher NLR have poorer prognoses. Future studies should perform more detailed investigations to decrease heterogeneity and determine the appropriate cut-off values for different races.

CADM1 regulates the G1/S transition and represses tumorigenicity through the Rb-E2F pathway in hepatocellular carcinoma.

BACKGROUND: Increasing evidence indicates that downregulation of cell adhesion molecule 1 (CADM1) contributes to tumorigenesis in various cancers. The present study was undertaken to investigate the CADM1 expression pattern in human hepatocellular carcinoma (HCC), and to elucidate the mechanism underlying CADM1-mediated tumor suppression. METHODS: CADM1 expression in HCC cell lines was measured by quantitative real-time PCR. The function of CADM1 in the context of tumor suppression in HCC cells was determined using proliferation assays, cell cycle analysis, EdU incorporation assays, in vitro colony formation analysis, and in vivo tumorigenicity assays. The mechanism by which CADM1 acts as a tumor suppressor gene in HCC was investigated using Western blotting analysis. RESULTS: Downregulation of CADM1 expression is frequently detected in both HCC cells and clinical samples. Restoration of CADM1 expression in HCC cell lines significantly inhibits cell growth and negatively regulates the G1/S transition. CADM1 overexpression can inhibit the tumorigenicity of HCC cells both in vitro and in vivo. Western blotting analysis revealed that ectopic expression of CADM1 in HCC cells is associated with increased expression of Retinoblastoma (Rb) protein. CONCLUSIONS: Our results showed that suppression of tumorigenesis by CADM1 may be mediated by the Rb-E2F pathway, involving upregulation of Rb protein levels. This pathway could therefore represent an attractive target for HCC therapy.

MicroRNA-452 promotes stem-like cells of hepatocellular carcinoma by inhibiting Sox7 involving Wnt/ß-catenin signaling pathway.

The decrease of microRNA-452 (miR-452) in gliomas promoted stem-like features and tumorigenesis. However, the role of miR-452, especially in regulating cancer stem cells (CSCs) in hepatocellular carcinoma (HCC) remains ambiguous. We enriched stem-like HCC cells by serial passages of hepatospheres with chemotherapeutic agents. Stem-like characteristics including the capabilities of chemo-resistance, stemness-related gene expression profiling, self-renewal, tumorigenicity and metastasis formation were detected. MiR-452 was markedly increased in the chemo-resistant hepatospheres and human HCC tissues. and the overexpression of miR-452 in HCC patients predicted poor overall survival. MiR-452 significantly promoted stem-like characteristics in vitro and in vivo. Further, Sox7 was identified as the direct target of miR-452, which could physically bind with ß-catenin and TCF4 in the nucleus and then inhibit the activity of Wnt/ß-catenin signaling pathway. Finally, the combined chemotherapy of doxorubicin and all-trans retinoic acid (ATRA) showed dramatically efficiency in suppressing HCC metastasis. These data suggested that miR-452 promoted stem-like traits of HCC, which might be a potential therapeutic target for HCC. The combination of doxorubicin and ATRA might be a promising therapy in HCC management.

Oncogenic role of microRNA-423-5p in hepatocellular carcinoma.

BACKGROUND: It has been found that microRNA-423-5p (miR423-5p) is an oncogenic factor and frequently upregulated in gastric carcinoma. However, the involvement of miR423-5p in hepatocellular carcinoma (HCC) has been rarely reported. The aim of this study was to assess whether miR423-5p is aberrantly expressed in HCC tissues, and to characterize its roles in the cancerous biology of HCC. METHODS: HCC and corresponding nonmalignant tissues were obtained from 115 patients during liver transplantation to detect the expression level of miR423-5p. The miR423-5p mimic and inhibitor were transfected into LM3 cell line. Cell viability assay, cell cycle analysis, transwell invasion and migration experiments were used to evaluate the oncogenic role of miR423-5p. RESULTS: miR423-5p was significantly upregulated in HCC compared with nonmalignant tissues, and this upregulation was negatively associated with recurrence-free survival. For patients beyond the Milan criteria, low expression of miR423-5p was correlated with better prognosis. Functional analysis showed that miR423-5p enhanced the proliferative, invasive and migratory capacity of HCC cells. CONCLUSIONS: miR423-5p contributed to the tumorigenesis and progression of HCC. It could be a new predictor in HCC patients beyond the Milan criteria and would help to improve patient outcomes and enlarge recipient pools of liver transplantation.

MRC-5 fibroblast-conditioned medium influences multiple pathways regulating invasion, migration, proliferation, and apoptosis in hepatocellular carcinoma.

BACKGROUND: Carcinoma associated fibroblasts (CAFs), an important component of tumor microenvironment, are capable of enhancing tumor cells invasion and migration through initiation of epithelial-mesenchymal transition (EMT). MRC-5 fibroblasts are one of the CAFs expressing alpha-smooth muscle actin. It is ascertained that medium conditioned by MRC-5 fibroblasts stimulate motility and invasion of breast cancer cells. However, its role in hepatocellular carcinoma (HCC) is less clear. The aim of our study was to investigate the effect of MRC-5-CM on HCC and explore the underlying mechanisms. METHODS AND RESULTS: Using a combination of techniques, the role of MRC-5-CM in HCC was evaluated. We determined that MRC-5-CM induced the non-classical EMT in Bel-7402 and MHCC-LM3 cell lines. Initiation of the non-classical EMT was mainly via quintessential redistribution of α-, ß- and γ-catenin, P120 catenin, E-cadherin, and N-cadherin, rather than up-regulation of typical EMT-related transcription factors (i.e., Snail, Twist1, ZEB-1 and ZEB2). We also found that MRC-5-CM potentiated both the migration and invasion of Bel-7402 and MHCC-LM3 cells in mesenchymal movement mode through activation of the α6, ß3, ß4, ß7 integrin/FAK pathway and upregulation of MMP2. The flow cytometric analysis showed that MRC-5-CM induced G1 phase arrest in Bel-7402 cells with a concomitant reduction of S phase cells. In contrast, MRC-5-CM induced S phase arrest in MHCC-LM3 cells with a concomitant reduction of cells in the G2/M phase. MRC-5-CM also inhibited apoptosis in Bel-7402 cells while inducing apoptosis in MHCC-LM3 cells. CONCLUSION: Collectively, MRC-5-CM promoted HCC cell motility and invasiveness through initiation of the non-classical EMT, including redistribution of α-, ß- and γ-catenin, P120 catenin, E-cadherin, and N-cadherin, activation of the integrin/FAK pathway, and upregulation of MMP2. Hence, MRC-5-CM exerted distinct roles in Bel-7402 and MHCC-LM3 cell viability by regulating cyclins, cyclin dependent kinases (CDKs), CDK inhibitors (CKIs), Bcl-2 family proteins and other unknown mechanosensors.

Polymorphisms of FGFR1 in HBV-related hepatocellular carcinoma.

Hepatitis B virus (HBV)-induced hepatocellular carcinoma (HCC) is one of the most commonly diagnosed cancers in China. It is important to understand the genetic mechanisms underlying the development and progression of HBV-related HCC and to identify new biomarkers for clinical treatment. The important role of fibroblast growth factor receptors (FGFRs) has been widely recognized in many types of cancers, but the association between FGFR polymorphisms and HCC carcinogenesis has been rarely reported. In this study, 199 patients with HBV-associated cirrhosis, 203 with HBV-associated HCC, and 184 healthy controls with no liver diseases were enrolled as participants. Using SNaPshot assays, five SNPs (rs13317, rs7825208, rs1047057, rs1047111, and rs1966265) of growth factor receptor genes were genotyped. Our results showed that the G/A and G/G genotypes at rs7825208 of FGFR1 were negatively correlated with HBV-related HCC (odds ratio (OR) = 0.45, 95% confidence interval (CI) = 0.22-0.93, P = 0.027). However, after Bonferroni correction, these significant differences no longer existed (P > 0.05). Our results indicated that these five polymorphisms of fibroblast growth factor receptor genes do not play any independent roles in the tumorigenesis and progression of HBV-related HCC in Han Chinese patients.

Association of RNF43 with cell cycle proteins involved in p53 pathway.

Our previous study has demonstrated that RNF43 could regulate the cell cycle in a p53-dependent manner in HCC. In this study, we aimed to access whether RNF43 could interact with cell cycle proteins involved in p53 pathway, including pRB, Cyclin D1 and MDM2. Totally, 123 paired HCC tissues and corresponding noncancerous tissues from HCC patients were included, and the expression of Cyclin D1, pRB and MDM2 was analyzed using tissue microarray. Our results showed the expression level of RNF43 in HCC was positively correlated with that of MDM2, Cyclin D1 and pRB-S780. There was no significant correlation between the expression of RNF43 and pRB-S807/S811. Indicating that RNF43 effected cell cycling by regulating the expression of pRB, Cyclin D1 and MDM2 proteins, and pRB-S780 but not pRB-S807/S811, was participated in RNF43 regulated cell cycling.

Prohibitin-2 promotes hepatocellular carcinoma malignancy progression in hypoxia based on a label-free quantitative proteomics strategy.

The rapid growth of hepatocellular carcinoma (HCC) leading to tumor hypoxia is a common pathological phenomenon. Meanwhile, tumor hypoxia can promote a change in the biological properties of tumor cells. It may enhance the survival of tumor cells under stress conditions, resulting in resistance to apoptosis and angiogenesis. The moleculars that could modulate the malignant phenotypes of HCC cells remain largely unknown. Based on label-free quantitative proteomic data, we found a significant upregulation of prohibitin-2 (PHB2) in HCC tissues. Treatment of hepatoma cells with small interfering RNAs against PHB2 suppressed cell growth and colony formation, led to G1 phase arrest and sensitized HCC cells to apoptosis. Moreover, inhibition of PHB2 expression dramatically repressed the ability of HCC cells to adapt to hypoxic microenvironments and resist chemotherapy-induced apoptosis. Thus, PHB2 in HCC supports the development and progression of hepatocellular malignancy to hypoxia, and implicates the potential antagonist function of PHB2 in transarterial chemoembolization treatment.

microRNA-200a is an independent prognostic factor of hepatocellular carcinoma and induces cell cycle arrest by targeting CDK6.

Deregulation of microRNA­200a (miR­200a) has been observed in different types of diseases, including cancers. However, the exact roles of miR­200a in hepatocellular carcinoma (HCC) are still largely unknown. We aimed to elucidate the prognostic implications of miR­200a and its biological function in HCC. Quantitative polymerase chain reaction was used to evaluate miR­200a expression. Western blotting was performed to evaluate the protein level. Gain-of-function studies were performed to evaluate the roles of miR­200a in HCC. Our results revealed that miR­200a was frequently downregulated in HCC. In addition, multivariate analysis confirmed that miR­200a was significantly associated with the overall survival of HCC patients. In vitro assays demonstrated that miR­200a suppressed the proliferation of HCC cells by induction of G1 phase arrest. Furthermore, CDK6 was identified as a novel functional target of miR­200a. Our data indicate that miR­200a functions as a potential tumor suppressor in HCC.

MicroRNA-503 inhibits the G1/S transition by downregulating cyclin D3 and E2F3 in hepatocellular carcinoma.

BACKGROUND: Increasing evidence indicates that deregulation of microRNAs (miRNAs) is involved in tumorigenesis. Downregulation of microRNA-503 has been observed in various types of diseases, including cancer. However, the biological function of miR-503 in hepatocellular carcinoma (HCC) is still largely unknown. In this study we aimed to elucidate the prognostic implications of miR-503 in HCC and its pathophysiologic role. METHODS: Quantitative reverse transcriptase polymerase chain reaction was used to evaluate miR-503 expression in HCC tissues and cell lines. Western blotting was performed to evaluate the expression of the miR-503 target genes. In vivo and in vitro assays were performed to evaluate the function of miR-503 in HCC. Luciferase reporter assay was employed to validate the miR-503 target genes. RESULTS: miR-503 was frequently downregulated in HCC cell lines and tissues. Low expression levels of miR-503 were associated with enhanced malignant potential such as portal vein tumor thrombi, histologic grade, TNM stage, AFP level and poor prognosis. Multivariate analysis indicated that miR-503 downregulation was significantly associated with worse overall survival of HCC patients. Functional studies showed miR-503 suppressed the proliferation of HCC cells by induction of G1 phase arrest through Rb-E2F signaling pathways, and thus may function as a tumor suppressor. Further investigation characterized two cell cycle-related molecules, cyclin D3 and E2F3, as the direct miR-503 targets. CONCLUSION: Our data highlight an important role for miR-503 in cell cycle regulation and in the molecular etiology of HCC, and implicate the potential application of miR-503 in prognosis prediction and miRNA-based HCC therapy.

Lentivirus-mediated CD/TK fusion gene transfection neural stem cell therapy for C6 glioblastoma.

A suicide gene can convert nontoxic prodrugs into toxic products to kill tumor cells. In this study, our aim was to transfect lentivirus-mediated CD/TK fusion gene into Wistar rat's neural stem cells (NSC) and then implant the NSC into a C6 glioma model to observe a C6 glioma growth inhibition effect. Primary NSC and stable transfection CD/TK fusion gene cell lines were established. To observe the tumor size and rat survival period in different groups, C6 glioma cell apoptosis and cell viability rate were applied to analyze the tumor inhibition effect of the neural stem cells' transfected CD/TK fusion gene. C6 cell viability showed that CDglyTK-NSC + GCV/5-Fc (group 1) was lower than CDglyTK-NSC (group 2), NSC + GCV/5-Fc (group 3), and control (group 4) from day 2 (p < 0.05), and the apoptosis rate was higher in group 1 compared with that of other groups (50.6%, p < 0.05) either in vitro or in vivo (35.47%, p < 0.05); both cell viability and apoptosis had no significance in the other three groups. In vivo, tumor size in group 1 was 7.76 ± 1.37 mm(3), which is smaller than the others (group2 27.28 ± 4.11 mm(3), group3 27.94 ± 2.08 and 28.61 ± 2.97 mm(3); p < 0.05). The other groups' tumor size was not significant (p > 0.05). Survival time of rats treated with CDglyTK-NSC + GCV/5-Fc (group 1) was significantly longer than that of the other groups (p < 0.05; group 1 48.86 ± 1.97, group 2 28.67 ± 3.75, group 3 31.5 ± 1.27, group 4 29.3 ± 1.33). We also showed that the transfected C6 cells had a migratory capacity toward gliomas in vivo. Transfected CD/TK fusion gene neural stem cells combined with propyl-guanosine and 5-flucytosine double prodrug significantly inhibit the development of glioma.

Induction of an EMT-like transformation and MET in vitro.

BACKGROUND: The epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET) play pivotal roles in metastasis of epithelial cancers. The distinction between them has shed new light on the molecular mechanisms of tumor metastasis. Recently, tumor microenvironment (TM) has been identified as one of the most potent inducers of EMT and MET. TM is characterized by its complexity and flexibility. The purpose of this study was to ascertain the exact effect of each distinct TM component on the evolution hepatocellular carcinoma (HCC) metastasis. METHODS: Two different cell culture models were used. The HCC cell line Bel-7402 was co-cultured with the normal liver cell line HL-7702 or with the retinal vascular endothelial cell line RF/6A in double-layer six-well plates, imitating the direct interaction between tumor-host cells and tumor cells. Bel-7402 was also cultured in the conditioned medium (CM) of the human lung fibroblast cell line MRC-5, HL-7702 or RF/6A, imitating an indirect interaction. Integrin ß1, ß3, ß4, ß7, laminin ß3, E-cadherin and Snail levels were measured by quantitative RT-PCR in tumor sepecimens from 42 resected HCC. RESULTS: We found that Bel-7402 cells co-cultured with HL-7702 or RF/6A cells were induced to undergo MET. The expression of E-cadherin, α-catenin and ß-catenin was up-regulated, accompanied with a strengthened E-cadherin/catenin complex on the membrane of co-cultured Bel-7402 cells. Consequently, the invasion and migration ability of cells was declined. Conversely, Bel-7402 cells cultured in conditioned medium from MRC-5 cells underwent an EMT-like transformation as the cells became elongated with increased invasion and migration ability. Furthermore, we demonstrated that HL-7702 cells could generally inhibit the tumorigenicity and viability of Bel-7402 cells. We also found that integrin ß1 expression was negatively associated with capsular formation, and that integrin ß4 expression was negatively associated with CK19 expression. CONCLUSION: Our findings highlight the strong influences exerted by TM on tumor progression through EMT and MET by impacting the expression of adhesion molecules, including the E-cadherin/catenin complex, laminins and integrins.