Clinical significance and biological roles of CARMA3 in human bladder carcinoma

Caspase recruitment domain and membrane-associated guanylate kinase-like domain protein 3 (CARMA3) was reported as an oncoprotein overexpressed in several cancers. The expression pattern of CARMA3 and its clinical significance in human bladder cancer have not been well characterized. In the present study, CARMA3 expression was analyzed in 90 archived bladder cancer specimens using immunohistochemistry, and the correlation between CARMA3 expression and clinicopathological parameters was evaluated. We found that CARMA3 was overexpressed in 35 of 90 (38.8 %) bladder cancer specimens. Significant association was observed between CARMA3 overexpression with tumor status (p?=?0.081) and tumor grade (p?=?0.027). To further explore the biological functions of CARMA3 in bladder cancer, we depleted CARMA3 in T24 and 5637 cell lines using small interfering RNA (siRNA). Using cell counting kit-8 (CCK8) assay and colony formation assay, we were able to show that CARMA3 depletion inhibited cell proliferation and colony number. Further study demonstrated that CARMA3 depletion decreased an expression of nuclear factor kappa B (NF-κB) targets cyclin D1 and Bcl-2 expression, as well as IκB phosphorylation. Luciferase reporter assay showed that CARMA3 depletion could downregulate NF-κB reporter activity. In conclusion, CARMA3 is overexpressed in bladder cancer and regulates malignant cell growth and NF-κB signaling, which makes CARMA3 a candidate therapeutic target for bladder cancer.     

Rsf-1 overexpression serves as a prognostic marker in human hepatocellular carcinoma

Rsf-1 (HBXAP) was recently reported to be overexpressed in various cancers and associated with the malignant behavior of cancer cells. However, the expression of Rsf-1 and its clinical significance in human hepatocellular carcinoma (HCC) have not been reported. In the present study, we analyzed the expression pattern of Rsf-1 in human HCC tissues and found that Rsf-1 was overexpressed in 41.1 % of HCC specimens. There was a significant association between Rsf-1 overexpression and tumor stage (p?=?0.0322), AFP (p?=?0.0184), and tumor relapse (p?=?0.0112). Furthermore, Rsf-1 overexpression correlated with poor overall survival in HCC patients (p?p?=?0.0079). Small interfering RNA (siRNA) knockdown in SK-Hep-1 cells with high endogenous Rsf-1 expression inhibited cell proliferation and colony formation, with downregulation of cyclin E protein. In conclusion, Rsf-1 is overexpressed in HCCs and serves as a novel tumor marker. Rsf-1 contributes to hepatocellular carcinoma cell growth through regulation of cell cycle proteins.     

The roles of human sucrose nonfermenting protein 2 homologue in the tumor-promoting functions of Rsf-1

Rsf-1 interacts with human sucrose nonfermenting protein 2 homologue (hSNF2H) to form a chromatin remodeling complex that participates in several biological processes. We have previously shown that Rsf-1 gene amplification was associated with the most aggressive type of ovarian cancer and cancer cells with Rsf-1 overexpression depended on Rsf-1 to survive. In this report, we determine if formation of the Rsf-1/hSNF2H complex could be one of the mechanisms contributing to tumor cell survival and growth in ovarian carcinomas. Based on immunohistochemistry, we found that Rsf-1 and hSNF2H were co-upregulated in ovarian cancer tissues. Ectopic expression of Rsf-1 in SKOV3 ovarian cancer cells with undetectable endogenous Rsf-1 expression enhanced hSNF2H protein levels and promoted SKOV3 tumor growth in a mouse xenograft model. Our studies also indicated that induction of Rsf-1 expression affected the molecular partnership of hSNF2H and translocated hSNF2H into nuclei where it colocalized with Rsf-1. Furthermore, analysis of Rsf-1 deletion mutants showed that the Rsf-D4 fragment contained the hSNF2H binding site based on coimmunoprecipitation and in vitro competition assays. As compared with other truncated mutants, expression of Rsf-D4 resulted in remarkable growth inhibition in ovarian cancer cells with Rsf-1 gene amplification and overexpression, but not in those without detectable Rsf-1 expression. The above findings suggest that interaction between Rsf-1 and hSNF2H may define a survival signal in those tumors overexpressing Rsf-1.     

CARMA3 is upregulated in human pancreatic carcinoma,and its depletion inhibits tumor proliferation,migration, and invasion

Elevated CARMA3 expression has been reported to be involved in tumor progression of several cancer types. In the present study, we examined the expression pattern of CARMA3 protein and its biological roles in human pancreatic carcinoma. Using immunohistochemistry, we checked CARMA3 protein expression in 95 pancreatic ductal carcinoma specimens. We found that CARMA3 was overexpressed in 34 of 95 (35.8 %) specimens. A significant association was observed between CARMA3 overexpression with histological grade (p?=?0.0099) and nodal status (p?=?0.0126). To further explore its biological roles, we knocked down CARMA3 expression in CAPAN2 cell line using small interfering RNA (siRNA). MTT growth assay, wound healing assay, and Transwell assay showed that CARMA3 depletion inhibited cell proliferation, migration, and invasion. We also showed that CARMA3 depletion inhibited EGF-induced nuclear factor-kappaB (NF-κB) activation and its target genes’ expression. The effect of CARMA3 depletion on NF-κB signaling was significantly reduced in Bcl10-depleted cells. In conclusion, CARMA3 is overexpressed in pancreatic cancer and regulates malignant cell growth, invasion, and NF-κB signaling, which was dependent on its association with Bcl10.     

Rab11通过NF-κB信号通路调控膀胱癌细胞的增殖和侵袭

目的:探讨Rab11调控膀胱癌细胞增殖和侵袭的分子机制。方法:用Western blot方法检测膀胱癌BIU-87、T24、RT4、5637细胞系中Rab11的内源表达量。在BIU-87（Rab11低表达）和T24（Rab11高表达）细胞系中分别转染Rab11过表达质粒和Rab11 siRNA。用荧光素酶报告实验检测转染后细胞内的NF-κB信号通路的活性,通过Western blot技术分析与NF-κB信号通路相关蛋白p-IκB的变化情况。用NF-κB抑制剂Bay 11-7082处理转染Rab11过表达质粒的BIU-87细胞系,通过Western blot检测细胞系中细胞周期相关因子cyclin D1和侵袭相关因子MMP9蛋白的变化。结果:转染Rab11过表达质粒的BIU-87细胞系中NF-κB活性水平提高,p-IκB表达量显著提高;而敲除Rab11后NF-κB活性受到抑制,p-IκB的表达受到抑制,而p-IκB与NF-κB信号通路的活性呈正相关。NF-κB抑制剂Bay 11-7082阻遏了Rab11诱导cyclin D1和MMP9表达上调的过程。结论:Rab11通过NF-κB信号通路调控膀胱癌细胞的增殖和侵袭。     

Enhanced MGMT expression contributes to temozolomide resistance in glioma stem-like cells

O6-methylguanine DNA methyltransferase （MGMT） can remove DNA alkylation adducts, thereby repairing damaged DNA and contributing to the drug resistance of gliomas to alkylating agents. In addition, glioma stem-like cells （GSCs） have been demonstrated to be involved in the recurrence and treatment resistance of gliomas. In this study, we aimed to investigate MGMT expression and regulatory mechanisms in GSCs and the association of MGMT with temozolomide （TMZ） sensitivity. GSCs were enriched from one MGMT-positive cell line （SF-767） and 7 MGMT-negative cell lines （U251, SKMG-4, SKMG-1, SF295, U87, MGR1, and MGR2） through serum-free clone culture. GSCs from the U251G, SKMG-4G, SF295G, and SKMG-1G cell lines became MGMT-positive, but those from the U87G, MGR1G, and MGR2G cell lines remained MGMT-negative. However, aJl the GSCs and their parental glJoma cell lines were positive for nuclear factor-KB （NF-KB）. In addition, GSCs were more resistant to TMZ than their parental glioma cell lines （P 〈 0.05）. However, there was no significant difference in the 50% inhibition concentration （ICo） of TMZ between MGMT-positive and MGMT-negatJve GSCs （P 〉 0.05）. When we treated the MGMT-positive GSCs with TMZ plus MG-132 （an NF-KB inhibitor）, the antitumor activity was significantly enhanced compared to that of GSCs treated with TMZ alone （P 〈 0.05）. Furthermore, we found that MGMT expression decreased through the down-regulation of NF-KB expression by MG-132. Our results show that MG-132 may inhibit NF-KB expression and further decrease MGMT expression, resulting in a synergistic effect on MGMT-positive GSCs. These results indicate that enhanced MGMT expression contributes to TMZ resistance in MGMT-positive GSCs.     

MKP1 repression is required for the chemosensitizing effects of NF-κB and PI3K inhibitors to cisplatin in non-small cell lung cancer

Treatment of non-small cell lung cancer (NSCLC) with cisplatin has a level of antitumor activity still modest. We have shown previously that MKP1/DUSP1 inhibits cisplatin-induced apoptosis in NSCLC cells and is overexpressed in tumors from most patients with stage I–II NSCLC. Here, using different NSCLC cell lines we found that MKP1 and NF-κB are differentially expressed. We studied whether targeting MKP1, NF-κB or both affects cisplatin-induced cell death. MKP1 is expressed in H460 and H727 cells. H727 and H1299 cells showed constitutive phosphorylation of Akt and increased NF-κB activity than did H460 cells. H460-MKP1-siRNA-expressing cells (but not H727-MKP1-siRNA or H1299-MKP1-siRNA cells) exhibit a marked increase in cisplatin response compared with parental cells. Treatment with the PI3K inhibitor LY294002 or the NF-κB inhibitor BAY11-7082 enhanced cisplatin antitumor activity in parental H1299 cells but only weakly affected responses of H727 and H460 cells. MKP1-siRNA expression enhanced the chemosensitization effect of LY294002 and BAY11-7082 on H727 and H460 cells. Additionally, NSCLC cell lines with higher NF-κB-constitutive activation were the most sensitive to PS-341 (Bortezomib), a non-specific NF-κB inhibitor. This finding suggests the proteasome as a suitable strategy in treating NSCLC tumors with high constitutive NF-κB activity. Altogether, these results showed that either an activated PI3K/Akt/NF-κB pathway and/or high MKP1 was linked to reduced sensitivity to cisplatin in NSCLC cells. Inhibition of NF-κB or PI3K potently enhanced cisplatin cytotoxicity in cells with endogenous or genetically induced low MKP1 levels. These findings support the potential improvement in cisplatin responses by co-targeting NF-κB or Akt and MKP1.     

Induction of cell apoptosis in non-small cell lung cancer cells by cyclin A1 small interfering RNA

Cyclin A1 and cyclin B1 are overexpressed in various tumors but are present at low levels in normal tissues. Cyclin A1 is restricted to germ cells undergoing meiosis. In order to explore the possibility of using cyclin A1 and cyclin B1 as anticancer targets, we knocked them down in two lung cancer cell lines, H157 and H596, using siRNA. As with cyclin A1 siRNA in lung cancer cell lines, cyclin B1, Cdc2 and CDK2 were all significantly downregulated. The S phase fraction increased significantly, and they eventually underwent apoptosis by way of downregulated intrinsic apoptotic pathways and modulators with upregulated extrinsic apoptotic pathways. Our study suggests that cyclin A1 might be a promising anticancer target specific to lung cancer.     

Rsf-1 overexpression correlates with poor prognosis and cell proliferation in colon cancer

Rsf-1 (HBXAP) was recently reported to be overexpressed in various cancers and associated with the malignant behavior of cancer cells. However, the expression of Rsf-1 and its biological roles in colon cancer have not been reported. The molecular mechanism of Rsf-1 in cancer aggressiveness remains ambiguous. In the present study, we analyzed the expression pattern of Rsf-1 in colon cancer tissues and found that Rsf-1 was overexpressed in 50.4?% of colon cancer specimens. There was a significant association between Rsf-1 overexpression and TNM stage (p?=?0.0205), lymph node metastasis (p?=?0.0025), and poor differentiation (p?=?0.0235). Furthermore, Rsf-1 overexpression correlated with a poor prognosis in colon cancer patients (p?=?0.0011). In addition, knockdown of Rsf-1 expression in HT29 and HCT116 cells with high endogenous Rsf-1 expression decrease cell proliferation and colony formation ability. Further analysis showed that Rsf-1 knockdown decreased cyclin E expression and phospho-Rb level. In conclusion, Rsf-1 is overexpressed in colon cancers and contributes to malignant cell growth by cyclin E and phospho-Rb modulation, which makes Rsf-1 a candidate therapeutic target in colon cancer.     

Anti-neoplastic effects of fucoxanthin and its deacetylated product, fucoxanthinol, on Burkitt's and Hodgkin's lymphoma cells

Fucoxanthin (FX) is a natural carotenoid with reported antitumorigenic activity. This study explored the effects of FX and its deacetylated product, fucoxanthinol (FXOH), on B-cell malignancies, including Burkitt's lymphoma, Hodgkin's lymphoma and Epstein-Barr virus-immortalized B cells. Both FX and FXOH reduced the viability of these malignant B cells in a dose-dependent manner accompanied by the induction of cell cycle arrest during G1 phase and caspase-dependent apoptosis. FXOH was approximately twice more potent than FX in these activities. In contrast, normal peripheral blood mononuclear cells were resistant to FX and FXOH. Strong and constitutive activation of nuclear factor-κB (NF-κB) is a common characteristic of many B-cell malignancies, and FXOH suppressed constitutive NF-κB activity. NF-κB inhibition was accompanied by downregulation of NF-κB-dependent anti-apoptotic and cell cycle regulator gene products, including Bcl-2, cIAP-2, XIAP, cyclin D1 and cyclin D2. The results indicated that FX and FXOH are potentially useful therapeutic agents in B-cell malignancies characterized by aberrant regulation of NF-κB.     

Differential regulation of cdk2 and cyclin D1 in irradiated human glioma cells

We have utilized a series of glioma cell lines to study the effects of ionizing radiation on the regulation of proteins that contribute to cell cycle progression. While no alterations of cyclin E or cdk4 were detected, a high percentage of glioma cell lines exhibited constitutive overexpression of cdk2 protein and aberrant patterns of cyclin D1 protein. The fraction of glioma cells expressing cdk2 was similar to that observed in normal astrocytes, but individual glioma cells overexpressed cdk2. In response to ionizing radiation, both cyclin D1 and cdk2 accumulated in control cells but not in gliomas with overexpressed cdk2 or aberrant cyclin D1. These novel findings provide the first evidence of altered cyclin-cdk regulation in gliomas in response to ionizing radiation.     

PELP1 signaling contributes to medulloblastoma progression by regulating the NF-κB pathway

Medulloblastoma (MB) is the most common and deadliest brain tumor in children. Proline-, glutamic acid-, and leucine-rich protein 1 (PELP1) is a scaffolding protein and its oncogenic signaling is implicated in the progression of several cancers. However, the role of PELP1 in the progression of MB remains unknown. The objective of this study is to examine the role of PELP1 in the progression of MB. Immunohistochemical analysis of MB tissue microarrays revealed that PELP1 is overexpressed in the MB specimens compared to normal brain. Knockdown of PELP1 reduced cell proliferation, cell survival, and cell invasion of MB cell lines. The RNA-sequencing analysis revealed that PELP1 knockdown significantly downregulated the pathways related to inflammation and extracellular matrix. Gene set enrichment analysis confirmed that the PELP1-regulated genes were negatively correlated with nuclear factor-κB (NF-κB), extracellular matrix, and angiogenesis gene sets. Interestingly, PELP1 knockdown reduced the expression of NF-κB target genes, NF-κB reporter activity, and inhibited the nuclear translocation of p65. Importantly, the knockdown of PELP1 significantly reduced in vivo MB progression in orthotopic models and improved the overall mice survival. Collectively, these results suggest that PELP1 could be a novel target for therapeutic intervention in MB.     

Cyclin D2 is overexpressed in proliferation centers of chronic lymphocytic leukemia/small lymphocytic lymphoma

The D cyclins are important cell cycle regulatory proteins involved in the pathogenesis of some lymphomas. Cyclin D1 overexpression is a hallmark of mantle cell lymphoma, whereas cyclins D2 and D3 have not been shown to be closely associated with any particular subtype of lymphoma. In the present study, we found that cyclin D2 was specifically overexpressed in the proliferation centers (PC) of all cases of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) examined (19/19). To examine the molecular mechanisms underlying this overexpression, we immunohistochemically examined the expression of nuclear factor (NF)-κB, p15, p16, p18, and p27 in the PC of six patients. Five cases showed upregulation of NF-κB expression, which is known to directly induce cyclin D2 by binding to the promoter region of CCND2. All six PC examined demonstrated downregulation of p27 expression. In contrast, upregulation of p15 expression was detected in five of six PC examined. This discrepancy suggests that unknown cell cycle regulatory mechanisms involving NF-κB-related pathways are also involved, because NF-κB upregulates cyclin D2 not only directly, but also indirectly through c-Myc, which is believed to downregulate both p27 and p15. In conclusion, cyclin D2 is overexpressed in the PC of CLL/SLL and this overexpression is due, in part, to the upregulation of NF-κB-related pathways.     

Use of RNA interference to target cyclin E-overexpressing hepatocellular carcinoma

RNA interference is the process by which double-stranded RNA directs sequence-specific degradation of mRNA. It has recently been shown that RNA interference can be triggered by 21-nucleotide duplexes of small interfering RNAs (siRNAs) in both cultured mammalian cells and adult mice. We hypothesize that siRNA can be used to specifically target oncogene overexpression in a therapeutic manner. Here, we show that overexpression of the oncogene cyclin E can be suppressed by up to 90% in hepatocellular carcinoma (HCC) cell lines by siRNA targeted on the coding region of cyclin E. We also find that depletion of cyclin E in this manner promotes apoptosis of HCC cells and blocks cell proliferation. Finally, we show that the siRNA oligos inhibits HCC tumor growth in nude mice. Thus, this study demonstrates the therapeutic potential of siRNA on the treatment of HCC by targeting overexpressed oncogenes such as cyclin E. Our results also indicate that cyclin E, which is overexpressed in 70% of HCCs, may serve as a novel therapeutic target.     

Expression and biological roles of SATB1 in human bladder cancer

Special AT-rich sequence-binding protein-1 (SATB1) has been recently reported to be overexpressed in various cancers and associate with the malignant behavior of cancer cells. However, the expression and potential roles of SATB1 in bladder cancer remains unclear. In the present study, SATB1 expression was analyzed in 85 archived bladder cancer specimens using immunohistochemistry and the correlations between SATB1 expression and clinicopathological parameters were evaluated. To further explore the biological functions of SATB1 in bladder cancer, siRNA knockdown was performed in 5637 and T24 bladder cancer cell lines. We then carried out CCK8 assay and examined cisplatin-induced apoptosis to address the roles of SATB1 in proliferation and apoptosis. We found that SATB1 was overexpressed in 33 of 85 (38.8 %) bladder cancer specimens. SATB1 overexpression associated with tumor grade (p?=?0.002) and tumor stage (p?=?0.027). SATB1 depletion in 5637 and T24 cells decreased cell proliferation while upregulating cisplatin-induced apoptosis. Further study demonstrated that SATB1 knockdown decreased cyclin D1 and cyclin E expression and upregulated caspase3 cleavage. In conclusion, SATB1 is overexpressed in bladder cancer and regulates malignant cell growth and apoptosis, which makes SATB1 a therapeutic target candidate for bladder cancer.     

Numblike regulates proliferation, apoptosis, and invasion of lung cancer cell

Numblike (Numbl), a conserved homolog of Drosophila Numb, has been proved to be implicated in early development of the nervous system. A recent study also showed that Numbl played an important role in tumorigenesis and invasion by suppressing NF-κB activation. However, the biological role of Numbl remains unknown in lung cancer up to now. To address the expression of Numbl in the lung cancer cell, four lung cancer cell lines (metastatic cell lines NCI-H292, 95-D, and non-metastatic cell lines A549, HCC827) and non-cancerous human bronchial epithelial cells were used to detect the protein expression of Numbl by western blotting. The results in this study indicated that the expression of Numbl was downregulated in human lung cancer cell lines, especially in metastatic cell lines. To investigate the role of Numbl in lung cancer cell proliferation, apoptosis, and invasion, we generated human lung cancer 95-D cell lines in which Numbl was either overexpressed or depleted. Subsequently, the effects of Numbl on the cell viability, cycle, apoptosis, and invasion properties in 95-D cells were determined with MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] assay, flow cytometry analysis, and Transwell invasion assays. The results indicated that Numbl could decrease cell viability, suppress cell proliferation and invasion, and promote cell apoptosis. In addition, we investigated the effects of Numbl on the expression of the following proteins: TRAF6 (tumor necrosis factor receptor-associated factor 6), p-p65 (phosphor-NF-κB), cyclin D1, caspase-3, and matrix metalloproteinase 9 (MMP9). Results showed that Numbl could decrease the expression of TRAF6, p-p65, cyclin D1, and MMP9 and increase the expression of caspase-3. All these results suggested that Numbl might be involved in the inhibition of growth, proliferation, and invasion of 95-D cells, as well as the potentiation of apoptosis of 95-D cells by abrogating TRAF6-induced activation of NF-κB.     

Comparison of the effect of p65 siRNA and curcumin in promoting apoptosis in esophageal squamous cell carcinoma cells and in nude mice

The activation of the NF-κB signaling pathway plays a critical role in carcinogenesis. The role of the NF-κB pathway in esophageal squamous cell carcinoma (ESCC) remains ill-defined. The objective was to detect whether p65siRNA and curcumin could promote ESCC cell apoptosis and increase the sensitivity of ESCC cells to chemotherapeutic drugs by inhibiting the NF-κB signaling pathway, and to compared these two treatments. In the present study, the status of the NF-κB pathway, in the two ESCC cell lines Eca109 and EC9706, was analyzed and the ability of p65 siRNA and curcumin alone or in combination with 5-FU to modulate this pathway in vitro and in vivo was investigated. The results showed that the NF-κB signaling pathway in the ESCC cell lines was constitutively activated. Both p65 siRNA and curcumin mediated suppression of activation of the NF-κB signaling pathway via inhibition of the expression of p65 or IκBα phosphorylation in ESCC cell lines. The cells treated with combination of p65 siRNA or curcumin and 5-FU revealed a lower cell viability and higher apoptosis compared to those treated with 5-FU alone. In a human ESCC xenograft model, p65 siRNA or curcumin and 5-FU alone reduced the tumor volume, respectively, but their combination had the strongest anticancer effects. Curcumin was more effective than p65 siRNA in vitro and in vivo. Overall, our results indicate that the constitutively activated NF-κB signaling pathway plays a crucial role in these two ESCC cell lines and both p65siRNA and curcumin can promote ESCC cell apoptosis and enhance the sensitivity to 5-FU through suppression of the NF-κB signaling pathway. It is still a long time before RNA interference will be used in the clinic. Therefore, curcumin is proved to be useful in the treatment of ESCC as it is a pharmacologically safe compound without side effects.