Xianting Huang

Expression of far upstream element (FUSE) binding protein 1 in human glioma is correlated with c-Myc and cell proliferation

Glioma is one of the most common type of primary intracranial tumor. Although great advances have been achieved in treatment of glioma, the underlying molecular mechanisms remain largely unknown. Previous studies demonstrated that FBP1 is a transcriptional regulator of c‐Myc and acts as an important prognostic indicator in many cancers. Our study aimed to assess the expression and function of FBP1 in human glioma. Immunohistochemical and Western blot analysis were performed in human glioma and normal brain tissues. High FBP1 expression (located in cell nuclei) was observed in 70 samples and its level was correlated with the grade of malignancy. A strongly positive correlation was observed between FBP1 and c‐Myc (P = 0.005) and Ki‐67 expression (P = 0.009). In a multivariate analysis, high FBP1 and c‐Myc expressions were showed to be associated with poor prognosis in glioma. While in vitro, following serum stimulation of starved U87MG cells, the expression of FBP1 was upregulated, as well as c‐Myc and PCNA. Moreover, knockdown of FBP1 by siRNA transfection diminished the expression of c‐Myc and arrested cell growth at G1 phase. Collectively, our results shows that the expression of FBP1 is in close correlation with c‐Myc level and cell proliferation in glioma and provides a potential strategy to develop FBP1 inhibitors as novel anti‐tumor agents.

Chaperonin containing TCP1, subunit 8 (CCT8) is upregulated in hepatocellular carcinoma and promotes HCC proliferation.

The development of molecular pathogenesis of hepatocellular carcinoma (HCC) is complex and involves alterations in the expression and conformation of assorted oncoproteins and tumor suppressors. Chaperonin containing TCP1 (CCT) is a cytolic molecular chaperone complex that is required for the correct folding of numerous proteins. In this study, we investigated a possible involvement of CCT subunit 8 (CCT8) in HCC development. Immunohistochemical analysis was performed in 102 human HCC samples. High CCT8 expression was detected in clinical HCC samples compared with adjacent noncancerous tissues. The univariate and multivariate survival analyses were also performed to determine their prognostic significance. Western blot confirmed the high expression of CCT8 in HCC compared with adjacent normal tissue. Moreover, the biological significance of the aberrant expression of CCT8 was investigated in HCC cell lines. Expression of CCT8 was correlated directly with the histologic grades and tumor size of HCC and high expression of CCT8 was associated with a poor prognosis. CCT8 depletion by siRNA inhibited cell proliferation and blocked S‐phase entry in HuH7 cells. These results suggested that CCT8 might be an oncogene and participate in HCC cell proliferation. These findings provide a potential therapeutic strategy for the treatment of HCC.

Effects of EHD2 interference on migration of esophageal squamous cell carcinoma

C-Terminal EH domain-containing protein 2 (EHD2) of the EHD family is associated with plasma membrane. We investigated the expression of EHD2 in human esophageal squamous cell carcinoma (ESCC) and the EHD2 expression to study the therapeutic effect of chemotherapy drugs. Western blot and immunohistochemistry were used to measure the expression of EHD2 protein in ESCC and adjacent normal tissue in 98 patients. EHD2 protein level was reduced in ESCC tissues in comparison with adjacent normal tissues. Under-expression of EHD2 increased the motility property of ESCC cell TE1 in vitro by wound-healing assays and transwell migration assays, and it was concurrent with the decreased expression of epithelial marker E-cadherin. Under-expression of EHD2 in TE1 can cause resistance to cisplatin. Our results suggested that EHD2 low expression is involved in the pathogenesis of ESCC, and it might be a favorable independent poor prognostic parameter for ESCC.

Spy1 induces de-ubiquitinating of RIP1 arrest and confers glioblastoma's resistance to tumor necrosis factor (TNF-α)-induced apoptosis through suppressing the association of CLIPR-59 and CYLD

Glioblastoma multiforme (GBM), a grade-IV glioma, is resistant to TNF-α induced apoptosis. CLIPR-59 modulates ubiquitination of RIP1, thus promoting Caspase-8 activation to induce apoptosis by TNF-α. Here we reported that CLIPR-59 was down-regulated in GBM cells and high-grade glioma tumor samples, which was associated with decreased cancer-free survival. In GBM cells, CLIPR-59 interacts with Spy1, resulting in its decreased association with CYLD, a de-ubiquitinating enzyme. Moreover, experimental reduction of Spy1 levels decreased GBM cells viability, while increased the lysine-63-dependent de-ubiquitinating activity of RIP1 via enhancing the binding ability of CLIPR-59 and CYLD in GBM, thus promoting Caspase-8 and Caspase-3 activation to induce apoptosis by TNF-α. These findings have identified a novel Spy1-CLIPR-59 interplay in GBM cells resistance to TNF-α-induced apoptosis revealing a potential target in the intervention of malignant brain tumors.

FBP1 and p27kip1 Expression After Sciatic Nerve Injury: Implications for Schwann Cells Proliferation and Differentiation

Far Upstream Element (FUSE) Binding Protein 1 (FBP1), first identified as a single‐stranded DNA (ssDNA) binding protein that binds to the FUSE, could modulate c‐myc mRNA levels and also has been shown to regulate tumor cell proliferation and replication of virus. Typically, FBP1 could active the translation of p27kip1 (p27) and participate in tumor growth. However, the expression and roles of FBP1 in peripheral system lesions and repair are still unknown. In our study, we found that FBP1 protein levels was relatively higher in the normal sciatic nerves, significantly decreased and reached a minimal level at Day 3, and then returned to the normal level at 4 weeks. Spatially, we observed that FBP1 had a major colocation in Schwann cells and FBP1 was connected with Ki‐67 and Oct‐6. In vitro, we detected the decreased level of FBP1 and p27 in the TNF‐α‐induced Schwann cells proliferation model, while increased expression in cAMP‐induced Schwann cells differentiation system. Specially, FBP1‐specific siRNA‐transfected SCs did not show fine and longer morphological change after cAMP treatment and had a decreased motility compared with normal. At 3 days after cAMP treatment and SC/neuron co‐cultures, p27 was transported to cytoplasm to form CDK4/6‐p27 to participate in SCs differentiation. In conclusion, we speculated that FBP1 and p27 were involved in SCs proliferation and the following differentiation in the sciatic nerve after crush by transporting p27 from nucleus to cytoplasm. J. Cell. Biochem. 115: 130–140, 2014.

A role for activator of G-protein signaling 3 (AGS3) in multiple myeloma.

Previous studies have demonstrated that activator of G-protein signaling 3 (AGS3; also known as GPSM1), a member of the AGS family, plays an important anti-apoptotic role through enhancing the phosphorylation of cyclic AMP response element-binding protein (p-CREB). In this report, we delineate the anti-apoptotic role of AGS3 in multiple myeloma (MM). To do this, we developed a cell apoptotic model induced by doxorubicin in MM. Our data indicate that decreased expression of AGS3 is correlated with reduced levels of p-CREB in the apoptotic model. The negative role of AGS3 in cell apoptosis was further confirmed by knocking down AGS3. The microenvironment has been shown to influence tumor cell phenotype in response to chemotherapy. Since cell adhesion-mediated drug resistance remains a major obstacle for successful treatment of MM, we constructed a cell adhesion model in MM and detected the changing of AGS3 protein expression. AGS3 siRNA reversed the high rate of MM cell adhesion to either fibronectin or HS-5 cells. Consistent with the reduced adhesion rate, the cells also exhibited reduced drug resistance to doxorubicin, mitoxantrone, and dexamethasone. Collectively, these data indicate that AGS3 may be represented as a good candidate for pursuing clinical trials in MM. Moreover, our data provide a clinical therapeutic target for MM and potentially other tumors that home and/or metastasize to the bone.

The role of the orphan G protein-coupled receptor 37 (GPR37) in multiple myeloma cells.

The orphan G protein-coupled receptor 37 (GPR37) is homologous to endothelin (ETB-R) and bombesin (GRP-R, NMB-R) receptors. The present study was undertaken to determine the expression and functional significance of GPR37 in human multiple myeloma (MM). We found that GPR37 was lowly expressed in MM cell adhesion model and highly expressed in proliferating cells. In vitro, meddling with the expression of GPR37 affected the CAM-DR by regulating the ability of cell adhesion and the activity of Akt and ERK in MM cells. Further studies indicated the positive role of GPR37 in the proliferation of MM cells.

Expression of small glutamine-rich TPR-containing protein A (SGTA) in Non-Hodgkin's Lymphomas promotes tumor proliferation and reverses cell adhesion-mediated drug resistance (CAM-DR).

The expression and biologic function of SGTA in Non-Hodgkins Lymphomas (NHL) was investigated in this study. Clinically, by immunohistochemistry analysis we detected SGTA expression in both reactive lymphoid tissues and NHL tissues. In addition, we also correlated high expression of SGTA with poor prognosis. Functionally, SGTA expression was positively related with cell proliferation and negative related with cell adhesion. Finally, SGTA knockdown induced adhesion-mediated drug resistance. Our finding supports a role of SGTA in NHL cell proliferation, adhesion and drug resistance, and it may pave the way for a novel therapeutic approach for CAM-DR in NHL.

Low expression of cyclic amp response element modulator-1 can increase the migration and invasion of esophageal squamous cell carcinoma

Cyclic AMP response element-binding protein (CREB) family can regulate biological functions of various types of cells and has relation with esophageal cancer cell migration and invasion. Cyclic AMP response element modulator-1 (CREM-1) is one member of the family with limited acquaintance. This study was conducted to investigate the effect of CREM-1 on migration and invasion in human esophageal squamous cell carcinoma (ESCC). The expression of CREM-1 protein in ESCC tissues with or without lymph nodes metastasis was determined by western blot. Immunohistochemical analysis of CREM-1 expression were carried out in paraffin-embedded sections of ESCC and correlated with clinical features. The roles of CREM-1 in migration and invasion were studied in TE1 cells through knocking CREM-1 down with siRNA or overexpression of CREM-1 in ECA109 cells. The regulations of CREM-1 on invasion and migration were determined by transwell and wounding healing assay. The effect of CREM-1 on chemotherapy drug was analyzed by Cell counting kit-8 assay. We found that the expression of CREM-1 was significantly downregulated in ESCC tissues with lymph nodes metastasis compared with the tissues without lymph nodes metastasis and was correlated with the clinical features of pathological grade, tumor stage and lymph node metastasis. Moreover, knocking CREM-1 down with siRNA increased cell migration and invasion in human ESCC cell lines TE1 while upregulation of CREM-1 inhibited the motility. Our data suggested that CREM-1 might play an important role in the regulation of tumor metastasis and invasion and serve as a tumor suppressor in human ESCC. We proposed that CREM-1 might be used as a potential therapeutic agent for human ESCC.