The risk of new-onset cancer associated with HFE C282Y and H63D mutations: evidence from 87,028 participants.

To investigate the association between mutation of HFE (the principal pathogenic gene in hereditary haemochromatosis) and risk of cancer, we conducted a meta-analysis of all available case-control or cohort studies relating to two missense mutations, C282Y and H63D mutations. Eligible studies were identified by searching databases including PubMed, Embase and the ISI Web of Knowledge. Overall and subgroup analyses were performed and odds ratios (ORs) combined with 95% confidence intervals (CIs) were applied to evaluate the association between C282Y mutation, H63D mutation and cancer risk. Sensitivity and cumulative analyses were used to evaluate the stability of the results. A total of 36 eligible studies were included, comprising 13,680 cases and 73,348 controls. C282Y was significantly associated with elevated cancer risk in a recessive genetic model (OR: 1.991, 95% CI: 1.448-2.737). On subgroup analysis stratified by cancer type, statistically significantly increased cancer risks were found for breast cancer, colorectal cancer and hepatocellular carcinoma in a recessive model. When stratified by territory, a significantly increased risk of cancer was found in Oceanic populations in a recessive model and in Asian populations in an allele model and dominant model. H63D mutation did not significantly increase overall cancer risk in any genetic model. However, when, stratified by territory, an increased cancer risk was found in the Asian population in an allele and dominant. C282Y but not H63D mutation was related to elevated cancer risk. Further large-scale studies considering gene-environment interactions and functional research should be conducted to further investigate this association.

Endothelial cells promote stem-like phenotype of glioma cells through activating the Hedgehog pathway.

Microenvironmental regulation of cancer stem cells (CSCs) strongly influences the onset and spread of cancer. The way in which glioma cells interact with their microenvironment and acquire the phenotypes of CSCs remains elusive. We investigated how communication between vascular endothelial cells and glioma cells promoted the properties of glioma stem cells (GSCs). We observed that CD133(+) GSCs were located closely to Shh(+) endothelial cells in specimens of human glioblastoma multiforme (GBM). In both in vitro and in vivo studies, we found that endothelial cells promoted the appearance of CSC-like glioma cells, as demonstrated by increases in tumourigenicity and expression of stemness genes such as Sox2, Olig2, Bmi1 and CD133 in glioma cells that were co-cultured with endothelial cells. Knockdown of Smo in glioma cells led to a significant reduction of their CSC-like phenotype formation in vitro and in vivo. Endothelial cells with Shh knockdown failed to promote Hedgehog (HH) pathway activation and CSC-like phenotype formation in co-cultured glioma cells. By examination of glioma tissue specimens from 65 patients, we found that the survival of glioma patients was closely correlated with the expression of both Shh by endothelial cells and Gli1 by perivascular glioma cells. Taken together, our study demonstrates that endothelial cells in the tumour microenvironment provide Shh to activate the HH signalling pathway in glioma cells, thereby promoting GSC properties and glioma propagation.

[Effects of Bmi1 gene on endothelial cells promoting glioma stem cell-like phenotype].

OBJECTIVE: To explore the effects of B-cell specific Maloney leukemia virus integration site 1 (Bmi1) gene on endothelial cells promoting glioma stem cell (GSC)-like phenotype. METHODS: Glioblastoma cell line GL261 and brain micro-vessel endothelial cell line b.END3 were used. Transwell co-culture system, limit dilution assay, xenograft, real-time polymerase chain reaction (PCR), Western blot, fluorescence activating cell sorter (FACS) and gene knock-down assay were used to determine the GSC-like phenotype and Bmi1 gene expression in glioma cells. RESULTS: Compared with the control of GL261 cell alone, (1) more and larger tumor spheres formed after co-culturing with endothelial cells (62.5% ± 1.5% vs 25.0% ± 4.6% at 40 cells/well, P = 0.000). Xenografts generated by GL261 cells with b.END3 cells appeared earlier and were larger than that by GL261 cells alone ((0.798 ± 0.297) cm(3) vs (0.362 ± 0.123) cm(3), P = 0.000); (2) CD133 positive glioma cells increased after co-culturing with endothelial cells (8.48% ± 0.78% vs 4.81% ± 0.37%, P = 0.000); (3) the expression of Bmi1 in co-cultured glioma cells was up-regulated at mRNA level (2.72 ± 0.18 vs 1.00 ± 0.15, P = 0.000) and at protein level; (4) the above phenomenon was attenuated when Bmi1 gene expression was inhibited by siRNA in glioma cells, CD133 positive portion of Bmi1-knockdown GL261 cells co-culturing with b.END3 cells decreased than that of wildtype GL261 cells (0.34% ± 0.21% vs 1.70% ± 0.69%, P = 0.025). CONCLUSION: Endothelial cells promote GSC-like phenotype by up-regulating the expression of Bmi1 in glioma cells.

TSSC3 represses self-renewal of osteosarcoma stem cells and Nanog expression by inhibiting the Src/Akt pathway.

Osteosarcoma is the most common type of bone cancer, and the second leading cause of cancer-related death in children and young adults. Osteosarcoma stem cells are essential for osteosarcoma initiation, metastasis, chemoresistance and recurrence. In the present study, we report that: 1) higher TSSC3 expression indicates a better prognosis for osteosarcoma patients, and; 2) overexpression of TSSC3 significantly decreases sphere-forming capacity, tumor initiation, stemness-related surface markers and Nanog expression in osteosarcoma cells. We also discovered that higher Nanog expression correlates to a worse prognosis for osteosarcoma patients, and overexpression of Nanog increases the stem-related phenotype in osteosarcoma cells. Knockdown of Nanog suppresses these phenotypes. Inhibition of Nanog expression and self-renewal of osteosarcoma cells by TSSC3 overexpression appears to be mediated through inactivation of the Src/Akt pathway. In the clinical setting, expression of TSSC3, p-Src and Nanog is associated with recurrence, metastasis and surgical intervention. Lower TSSC3 expression, higher Nanog expression or higher p-Src expression indicate a poor prognosis for osteosarcoma patients. Overall, our study demonstrates that TSSC3 inhibits the stem-like phenotype and Nanog expression by inactivation of the Src/Akt pathway; this emphasizes the importance of Nanog in osteosarcoma stem cells.

Advances in osteosarcoma stem cell research and opportunities for novel therapeutic targets.

Osteosarcoma is the most common type of bone cancer, especially in children and young adults. The primary treatment for osteosarcoma is a combination of surgery and chemotherapy, however prognoses remain poor due to chemoresistance and early metastases. Osteosarcoma stem cells appear to play central roles in tumor recurrence, metastases and chemoresistance via self-renewal and differentiation. Targeting these cells may provide a novel strategy in the treatment of osteosarcoma. This review summarizes current knowledge of this rare phenotype and recent advances in understanding the functions OSCs (osteosarcoma stem cells) in osteosarcoma, with the aim of improving therapies in the future.

RanBP9/TSSC3 complex cooperates to suppress anoikis resistance and metastasis via inhibiting Src-mediated Akt signaling in osteosarcoma.

Suppression of anoikis is a prerequisite for tumor cell metastasis, which is correlated with chemoresistance and poor prognosis. We characterized a novel interaction between RanBP9 SPRY domain and TSSC3 PH domain by which RanBP9/TSSC3 complex exerts transcription and post-translation regulation in osteosarcoma. RanBP9/TSSC3 complex was inversely correlated with a highly anoikis-resistant phenotype in osteosarcoma cells and metastasis in human osteosarcoma. RanBP9 cooperated with TSSC3 to inhibit anchorage-independent growth and to promote anoikis in vitro and suppress lung metastasis in vivo. Moreover, RanBP9 SPRY domain was required for RanBP9/TSSC3 complex-mediated anoikis resistance. Mechanistically, RanBP9 formed a ternary complex with TSSC3 and Src to scaffold this interaction, which suppressed both Src and Src-dependent Akt pathway activations and facilitated mitochondrial-associated anoikis. Collectively, the newly identified RanBP9/TSSC3 complex cooperatively suppress metastasis via downregulation of Src-dependent Akt pathway to expedite mitochondrial-associated anoikis. This study provides a biological basis for exploring the therapeutic significance of dual targeting of RanBP9 and TSSC3 in osteosarcoma.

Downregulation of tumor suppressing STF cDNA 3 promotes epithelial-mesenchymal transition and tumor metastasis of osteosarcoma by the Wnt/GSK-3ß/ß-catenin/Snail signaling pathway.

Epithelial to mesenchymal transition (EMT) has received considerable attention as a conceptual paradigm for explaining the invasive and metastatic behavior of cells during cancer progression. Our previous study showed that loss of expression of TSSC3 is positively associated with osteosarcoma malignancy and progression. However, whether TSSC3 mediates EMT in osteosarcoma is poorly understood. In the present study, we determined that TSSC3 downregulation induced cell migration and invasion ability and promoted mesenchymal transition of osteosarcoma cells by upregulating mesenchymal markers and inhibiting the epithelial markers. Furthermore, TSSC3 downregulation elicited a signaling cascade that included increased levels of Wnt3a and LRP5, inactivation of GSK-3ß, accumulation of nuclear ß-catenin and Snail, the augmented binding of ß-catenin to TCF-4, and accordingly increased the expression of Wnt target genes (CD44, MMP7). The gene knockdown of these signaling proteins could inhibit TSSC3 downregulation-promoted EMT, migration, and invasion in osteosarcoma. Finally, TSSC3 overexpression obviously inhibited cell migration, invasion, and repressed mesenchymal phenotypes, reducing lung metastasis through GSK-3ß activation. Collectively, TSSC3 downregulation promotes the EMT of osteosarcoma cells by regulating EMT markers via a signal transduction pathway that involves Snail, Wnt-ß-catenin/TCF, and GSK-3ß.

Enhancer of zeste homolog 2 silencing inhibits tumor growth and lung metastasis in osteosarcoma.

The enhancer of zeste homolog 2 (EZH2) methyltransferase is the catalytic subunit of polycomb repressive complex 2 (PRC2), which acts as a transcription repressor via the trimethylation of lysine 27 of histone 3 (H3K27me3). EZH2 has been recognised as an oncogene in several types of tumors; however, its role in osteosarcoma has not been fully elucidated. Herein, we show that EZH2 silencing inhibits tumor growth and lung metastasis in osteosarcoma by facilitating re-expression of the imprinting gene tumor-suppressing STF cDNA 3 (TSSC3). Our previous study showed that TSSC3 acts as a tumor suppressor in osteosarcoma. In this study, we found that EZH2 was abnormally elevated in osteosarcoma, and its overexpression was associated with poor prognosis in osteosarcoma. Silencing of EZH2 resulted in tumor growth inhibition, apoptosis and chemosensitivity enhancement. Moreover, suppression of EZH2 markedly inhibited tumor growth and lung metastasis in vivo. Furthermore, EZH2 knockdown facilitated the re-expression of TSSC3 by reducing H3K27me3 in the promoter region. Cotransfection with siEZH2 and siTSSC3 could partially reverse the ability of siEZH2 alone. We have demonstrated that EZH2 plays a crucial role in tumor growth and distant metastasis in osteosarcoma; its oncogenic role is related to its regulation of the expression of TSSC3.

Is CD133 expression a prognostic biomarker of non-small-cell lung cancer? A systematic review and meta-analysis.

BACKGROUND: The clinical and prognostic significance of CD133 in non-small-cell lung cancer (NSCLC) remains controversial. To clarify a precise determinant of the clinical significance of CD133, we conducted a systematic review and meta-analysis to evaluate the association of CD133 with prognosis and clinicopathological features of NSCLC patients. METHODS: The electronic and manual searches were performed through the database of Pubmed, Medline, Web of Science, Scopus, and Chinese CNKI (from January 1, 1982 to January 1, 2014) for titles and abstracts by using the following keywords: "CD133", "ac133" or "Prominin-1", and "lung cancer" to identify the studies eligible for our analysis. Meta-analysis was performed by using Review Manager 5.0 and the outcomes included the overall survival and various clinicopathological features. RESULTS: A total of 23 studies were finally included, and our results showed that CD133 level was significantly correlated with the overall survival (OR = 2.25, 95% CI: 1.24-4.07, P = 0.008) of NSCLC patients but not with the disease free survival (OR = 1.33, 95% CI = 0.77-2.30, P = 0.31). With respect to clinicopathological features, CD133 level was positively correlated with lymph node metastasis (OR = 1.99, 95%CI = 1.06-3.74, P = 0.03), but not correlated with the histological classification (OR = 1.00, 95%CI = 0.81-1.23, P = 0.99(ac), OR = 0.87, 95%CI = 0.61-1.24, P = 0.45(sc)), or differentiation (OR = 0.94, 95%CI 0.53-1.68, Z = 0.20, P = 0.84 random-effect) of NSCLC patients. CONCLUSION: High level of CD133 expression trends to correlate with a worse prognosis and a higher rate of lymph node metastasis in NSCLC patients, revealing CD133 as a potential pathological prognostic marker for NSCLC patients.

Glioma stem cells enhance endothelial cell migration and proliferation via the Hedgehog pathway.

The aim of the present study was to determine the possible mechanism underlying the enhanced migration and proliferation of endothelial cells caused by glioma stem cells (GSCs). Tumor spheres enriched in GSCs derived from the mouse GL261 glioma cell line, and the brain microvessel endothelial cell line, b.END3, were used in this study. A Transwell co-culture system, RNAi experiments, quantitative polymerase chain reaction, western blotting and enzyme-linked immunosorbent, cell counting kit-8 (CCK-8) proliferation, Transwell migration and wound-healing assays were used in this study to determine the migration and proliferation ability, as well as the Hedgehog (HH) pathway-related gene expression in the b.END3 cells. Based on the results, it was demonstrated that the migration and proliferation of the endothelial cells were enhanced following co-culture with GSCs. The gene expression of the HH pathway-related genes, Sonic Hedgehog (Shh) and Hedgehog-interacting protein (Hhip) was altered in the endothelial cells when co-cultured with GSCs. Overexpression of glioma-associated oncogene homolog 1 indicated activation of the HH pathway. Following knockdown of smoothened (Smo) in the endothelial cells, the migration and proliferation abilities of the cells were inhibited. GSCs have little effect on enhancing these behaviors in endothelial cells following Smo-knockdown. Further investigation revealed that Shh levels in the supernatant of the co-culture system were elevated, indicating the importance of secreted Shh from the endothelial cells. In conclusion, GSCs enhanced the migration and proliferation of the endothelial cells in vitro, which was likely associated with the activation of the HH pathway in the endothelial cells, caused by the increased secretion of Shh.