Elucidating the expression and function of Numbl during cell adhesion-mediated drug resistance (CAM-DR) in multiple myeloma (MM).

BACKGROUND: Cell adhesion-mediated drug resistance (CAM-DR) is a major clinical problem that prevents successful treatment of multiple myeloma (MM). In particular, the expression levels of integrin ß1 and its sub-cellular distribution (internalization and trafficking) are strongly associated with CAM-DR development. METHODS: Development of an adhesion model of established MM cell lines and detection of Numbl and Integrinß1 expression by Western Blot analysis. The interaction between Numbl and Integrinß1 was assessed by a co-immunoprecipitation (CO-IP) method. Calcein AM assay was performed to investigate the levels of cell adhesion. Finally, the extent of CAM-DR in myeloma cells was measured using cell viability assay and flow cytometry analysis. RESULTS: Our preliminary date suggest that Numbl is differentially expressed in a cell adhesion model of MM cell lines. In addition to binding to the phosphotyrosine-binding (PTB) domain, the carboxyl terminal of Numbl can also interact with integrin ß1 to regulate the cell cycle by activating the pro-survival PI3K/AKT signaling pathway. This study intends to verify and elucidate the interaction between Numbl and integrin ß1 and its functional outcome on CAM-DR. We have designed and developed a CAM-DR model using MM cells coated with either fibronectin or bone marrow stromal cells. We assessed whether Numbl influences cell-cycle progression and whether it, in turn, contributes to activation of PI3K/AKT signal pathway through the adjustment of its carboxyl end. Finally, we showed that the interaction of Numbl with integrin ß1 promotes the formation of CAM-DR in MM cells. CONCLUSIONS: Our findings elucidated the specific molecular mechanisms of CAM-DR induction and confirmed that Numbl is crucial for the development of CAM-DR in MM cells.

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.

High expression of SGTA in esophageal squamous cell carcinoma correlates with proliferation and poor prognosis.

Receptor tyrosine kinases (RTKs) expression and the growth factor such as platelet-derived growth factor (PDGF) and their receptors have been considered relevant in the process of angiogenesis and dissemination in esophageal squamous cell carcinoma (ESCC). Small glutamine-rich tetratricopeptide repeat-containing protein alpha (SGTA) downstream of RTK signaling was a critical regulator of PDGF receptors (PDGFR) stability. The aim of the present study was to examine the expression of SGTA and to elucidate its clinicopathologic significance in ESCC. Immunohistochemistry and western blot analysis were performed for SGTA in ESCC samples. SGTA was up-regulated in ESCC as compared with the adjacent normal tissue. High expression of SGTA was associated with tumor grade (P < 0.01), and SGTA was positively correlated with proliferation marker Ki-67 (P < 0.05). Univariate analysis showed that SGTA expression did has a remarkable prediction for poor prognosis (P = 0.016). Knockdown or overexpression of SGTA affected ESCC cells proliferation and cell cycle. Additionally, after ESCC cells silenced for SGTA were treated with cisplatin (an anti-ESCC agent), the cell growth was down-regulated. These findings suggested that SGTA was involved in the pathogenesis of ESCC and might indicate a poor prognosis for ESCC patients.

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.

Expression of NF45 correlates with malignant grade in gliomas and plays a pivotal role in tumor growth.

Nuclear factor of activated T cells 45 kDa (NF45), is a transcription factor that interacts with NF90 to regulate gene expression. It has been proved to be associated with tumor proliferation in various human malignancies. However, the role of NF45 in glioma is poorly understood. The aim of our study was to examine the relationship between NF45 expression and pathological grade in glioma and the impact of NF45 on the proliferation of glioma cells. Expression levels of NF45 are significantly elevated in high-grade human tissue samples compared with low-grade human glioma tissues samples (P < 0.0001) in Western blot analysis. The result of immunohistochemical also revealed that the expression of NF45 was overexpressed in 121 resected gliomas of different pathologic grades and associated with Ki-67. To investigate the role of NF45 in glioma carcinogenesis, we reduced the expression of NF45 by small interfering RNAs, and results showed suppression of cell proliferation, arrest of the cell cycle, and reduction in clone in vitro. Importantly, we show that SiNF45 can induce the expression of p21 and reduce the expression of proliferating cell nuclear antigen (PCNA) and cyclin E. These findings indicate that NF45 plays an important role in the growth regulation of glioma cells, suggesting that NF45 maybe a molecular marker for pathology and a novel therapeutic target for malignant glioma.

Suppression of KIF3B expression inhibits human hepatocellular carcinoma proliferation.

BACKGROUND: Human hepatocellular carcinoma (HCC) is one of the most common fatal cancers and an important health problem worldwide, but its mechanism is still unclear. Microtubule (MT) kinesin motor proteins orchestrate a variety of cellular processes (e.g. mitosis, motility and organelle transportation) and have been involved in human carcinogenesis. KIF3B, the kinesin superfamily of proteins (KIFs), plays an important role in the regulation of mitotic progression. AIM: The expression of KIF3B and its involvement in HCC was investigated. METHODS: Western blot and immunohistochemistry were used to measure the expression of KIF3B protein in HCC and adjacent non-tumorous tissues in 57 patients and Cell Counting Kit-8 to analyze the effects of growth and interference of KIF3B in the cell cycle process. RESULTS: KIF3B protein level was increased in HCC tissues compared with the adjacent non-tumorous tissues. It was significantly associated with histological differentiation, tumor size, the level of alpha fetal protein (AFP) and proliferation marker Ki-67. Over-expression of KIF3B was correlated with poor survival. Following release of HepG2 cells from serum starvation, the expression of KIF3B was up-regulated. Furthermore, suppression of KIF3B not only decreased cancer cell growth but also induced apoptosis of cells. CONCLUSIONS: Our results suggested that KIF3B expression was upregulated in HCC tumor tissues and proliferating HCC cells, and an increased KIF3B expression was associated with poor overall survival. KIF3B over-expression is involved in the pathogenesis of hepatocellular carcinoma and may serve as a potential therapeutic target for human HCC.

Low expression of cyclinH and cyclin-dependent kinase 7 can decrease the proliferation of human esophageal squamous cell carcinoma.

BACKGROUND: Increased expression of cyclinH (CCNH) and cyclin-dependent kinase 7 (CDK7) has a relationship with poor prognosis in most human cancers. AIM: Investigate the expression of CCNH and CDK7 in human esophageal squamous cell carcinoma (ESCC) and the effect of chemotherapy on their expression. METHODS: Western blotting and immunohistochemistry were used to measure the expression of CCNH and CDK7 proteins in ESCC and adjacent normal tissue in 98 patients. We use Cell Counting Kit-8 and cell flow to analyze the effects of cisplatin and interference of CCNH and CDK7 in cell cycle process. RESULTS: Immunohistochemical analysis showed that CCNH and CDK7 expression were significantly associated with unfavorable clinicopathologic variables. CCNH and CDK7 protein levels were elevated in ESCC tissues in comparison with adjacent normal tissues. Survival analysis revealed that CCNH and CDK7 overexpression were significantly associated with overall survival (P < 0.001). Cisplatin or interference of CCNH or CDK7 led cells to grow slowly. Overexpression of CCNH and CDK7 in TE1 cells can lead to resistance to cisplatin. CONCLUSIONS: We can conclude that CCNH and CDK7 may play an important role in the tumorigenesis and development of ESCC. CCNH and CDK7 expression affected the chemotherapy of tumor.

Interaction with AEG-1 and MDM2 is associated with glioma development and progression and correlates with poor prognosis.

Glioma is the most common central nervous system tumor with poor prognosis. The AEG-1 (Astrocyte Elevated Gene 1) gene displays oncogenic characteristics, including proliferation, metastasis, chemoresistance, invasion, and evasion of apoptosis, and is strongly linked to the occurrence of glioma. Here, we elucidated the potential contribution of AEG-1 in human glioma pathogenesis. In glioma cells, AEG-1 could directly interact with Murine Double Minute-2 (MDM2) protein resulting in MDM2-p53-mediated cell proliferation and apoptosis. MDM2 is being revealed as an oncoprotein, which is involved in many human cancers progression. By immunohistochemical and a multivariate analysis, expressions of AEG-1 and MDM2 were elevated in glioma and high AEG-1 and MDM2 expressions were showed to be correlated with poor prognosis. AEG-1-MDM2 interaction prolonged stabilization of MDM2 where AEG-1 inhibited ubiquitination and subsequent proteasome-mediated degradation of MDM2 protein. Moreover, slicing AEG-1 blocked MDM2 expression and then impacted MDM2-p53 pathway that influenced cell proliferation and apoptosis. These findings uncover a novel AEG-1-MDM2 interplay by which AEG-1 augments glioma progression and reveal a viable potential therapy for the treatment of glioma patients.

CRMP1 Interacted with Spy1 During the Collapse of Growth Cones Induced by Sema3A and Acted on Regeneration After Sciatic Nerve Crush.

CRMP1, a member of the collapsin response mediator protein family (CRMPs), was reported to regulate axon outgrowth in Sema3A signaling pathways via interactions with its co-receptor protein neuropilin-1 and plexin-As through the Fyn-cyclin-dependent kinase 5 (CDK5) cascade and the sequential phosphorylation of CRMP1 by lycogen synthase kinase-3ß (GSK-3ß). Using yeast two-hybrid, we identified a new molecule, Speedy A1 (Spy1), a member of the Speedy/RINGO family, with an interaction with CRMP1. Besides, for the first time, we observed the association of CRMP1 with actin. Based on this, we wondered the association of them and their function in Sema3A-induced growth cones collapse and regeneration process after SNC. During our study, we constructed overexpression plasmid and short hairpin RNA (shRNA) to question the relationship of CRMP1/Spy1 and CRMP1/actin. We observed the interactions of CRMP1/Spy1 and CRMP1/actin. Besides, we found that Spy1 could affect CRMP1 phosphorylation actived by CDK5 and that enhanced CRMP1 phosphorylation might disturb the combination of CRMP1 and actin, which would contribute to abnormal of Sema3A-induced growth cones collapse and finally lead to influent regeneration process after rat sciatic nerve crush. Through rat walk footprint test, we also observed the variance during regeneration progress, respectively. We speculated that CRMP1 interacted with Spy1 which would disturb the association of CRMP1 with actin and was involved in the collapse of growth cones induced by Sema3A and regeneration after sciatic nerve crush.

LAP3 promotes glioma progression by regulating proliferation, migration and invasion of glioma cells.

Leucine aminopeptidase 3 (LAP3), belonging to the M1 family, has been proved to catalyze the hydrolysis of leucine residues. Leucine aminopeptidases are involved in many pathological disorders and regulate cell proliferation, invasion and/or angiogenesis of tumor. Recent study showed that LAP3 is highly expressed in several malignant and affects tumor angiogenesis. We aimed at investigating the clinical significance of LAP3 expression in human gliomas and its biological function in glioma cells. RT-PCR, Western blot and immunohistochemistry analysis were used to detect the expression levels of LAP3 in 121 glioma tissues, high LAP3 expression was correlated with the grade of malignancy and poor prognosis of glioma patients. In vitro, after increasing of LAP3 by myc-LAP3 transfection and knockdown of LAP3 by siRNA transfection in glioma cells, cell viability, cell cycle, migration and invasion were determined with CCK8 assay, flow cytometry, wound healing and transwell invasion assays. The results indicated that increasing LAP3 could promte cell viability, cell cycle, migration and invasion, knockdown LAP3 could decrease cell viability, suppress cell proliferation, migration and invasion. Our findings uncover that LAP3 might be a new prognostic factor and be close correlation with glioma cell growth, migration, invasion.

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 cell's resistance to TNF-α-induced apoptosis revealing a potential target in the intervention of malignant brain tumors.

The role of FoxJ2 in the migration of human glioma cells.

Previous studies have demonstrated that FoxJ2 (forkhead box J2) is a member of Forkhead Box transcription factors and acts as an important prognostic indicator in human breast cancer. Our study aimed to assess the expression and function in human glioma. Western blot analysis and immunohistochemistry were performed in human glioma tissues. Low FoxJ2 expression was observed in 80 samples and its level was correlated with the grade of malignancy. A strongly positive correlation was observed between FoxJ2 and E-cadherin. Overexpression of FoxJ2 increased E-cadherin expression and decreased vimentin expression. The wound healing and transwell assays showed that overexpression of FoxJ2 significantly inhibited their migration in U87 cells. Consistent with this, knockdown of FoxJ2 promoted cellular motility. In a word, FoxJ2 suppressed cell migration and invasion in glioma, which might be a potential novel molecular targeted therapy for surgery and immune treatment.

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.

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.

Glycinamide ribonucleotide formyl transferase is frequently overexpressed in glioma and critically regulates the proliferation of glioma cells.

AIMS: Current treatments for the most common form of brain tumor, glioma, are disappointing in their effectiveness. Low expression levels of GART, an enzyme in the core nucleotide metabolism, significantly correlate with chemosensitivity, conferring a survival advantage to tumor cells. Our study aimed to explore the expression and function of GART in glioma. METHODS: Immunohistochemical and Western blot analysis were performed in 70 cases of human gliomas and normal brain tissues. We mainly used cell growth assay and multicellular tumor spheroid formation assay to evaluate the proliferation and chemosensitivity of glioma cells. RESULTS: High GART expression (most cancer cells cytoplasm stained) was observed in 70 specimens and was related to the grade of malignancy. We also reviewed each grade of tumors separately and investigated whether GART expression predicted patient survival within each subgroup. In brief, GART overexpression was significantly associated with overall survival (P=0.03). Interestingly, transfecting cells with GART-siRNA suppressed proliferation and enhanced temozolomide (TMZ)-induced apoptosis in glioma cells. CONCLUSION: The current results showed that GART expression was associated with glioma grade and that high GART protein expression might be related to poor outcome.