@article {235, title = {Knockdown of cullin 4A inhibits growth and increases chemosensitivity in lung cancer cells.}, journal = {J Cell Mol Med}, volume = {20}, year = {2016}, month = {2016 Jul}, pages = {1295-306}, abstract = {

Cullin 4A (Cul4A) has been observed to be overexpressed in various cancers. In this study, the role of Cul4A in the growth and chemosensitivity in lung cancer cells were studied. We showed that Cul4A is overexpressed in lung cancer cells and tissues. Knockdown of the Cul4A expression by shRNA in lung cancer cells resulted in decreased cellular proliferation and growth in lung cancer cells. Increased sensitivity to gemcitabine, a chemotherapy drug, was also noted in those Cul4A knockdown lung cancer cells. Moreover, increased expression of p21, transforming growth factor (TGF)-β inducible early gene-1 (TIEG1) and TGF beta-induced (TGFBI) was observed in lung cancer cells after Cul4A knockdown, which may be partially related to increased chemosensitivity to gemcitabine. G0/G1 cell cycle arrest was also noted after Cul4A knockdown. Notably, decreased tumour growth and increased chemosensitivity to gemcitabine were also noted after Cul4A knockdown in lung cancer xenograft nude mice models. In summary, our study showed that targeting Cul4A with RNAi or other techniques may provide a possible insight to the development of lung cancer therapy in the future.

}, issn = {1582-4934}, doi = {10.1111/jcmm.12811}, author = {Hung, Ming-Szu and Chen, I-Chuan and You, Liang and Jablons, David M and Li, Ya-Chin and Jiang-Hua Mao and Xu, Zhidong and Lung, Jr-Hau and Yang, Cheng-Ta and Liu, Shih-Tung} } @article {223, title = {Analysis of lung tumor initiation and progression in transgenic mice for Cre-inducible overexpression of Cul4A gene.}, journal = {Thorac Cancer}, volume = {6}, year = {2015}, month = {2015 Jul}, pages = {480-7}, abstract = {

BACKGROUND: Lung cancer is the leading cause of morbidity and death worldwide. Although the available lung cancer animal models have been informative and further propel our understanding of human lung cancer, they still do not fully recapitulate the complexities of human lung cancer. The pathogenesis of lung cancer remains highly elusive because of its aggressive biologic nature and considerable heterogeneity, compared to other cancers. The association of Cul4A amplification with aggressive tumor growth and poor prognosis has been suggested. Our previous study suggested that Cul4A is oncogenic in vitro, but its oncogenic role in vivo has not been studied.

METHODS: Viral delivery approaches have been used extensively to model cancer in mouse models. In our experiments, we used Cre-recombinase induced overexpression of the Cul4A gene in transgenic mice to study the role of Cul4A on lung tumor initiation and progression and have developed a new model of lung tumor development in mice harboring a conditionally expressed allele of Cul4A.

RESULTS: Here we show that the use of a recombinant adenovirus expressing Cre-recombinase ("AdenoCre") to induce Cul4A overexpression in the lungs of mice allows controls of the timing and multiplicity of tumor initiation. Following our mouse models, we are able to study the potential role of Cul4A in the development and progression in pulmonary adenocarcinoma as well.

CONCLUSION: Our findings indicate that Cul4A is oncogenic in vivo, and this mouse model is a tool in understanding the mechanisms of Cul4A in human cancers and for testing experimental therapies targeting Cul4A.

}, issn = {1759-7706}, doi = {10.1111/1759-7714.12257}, author = {Wang, Yang and Xu, Zhidong and Jiang-Hua Mao and Hung, Ming-Szu and Hsieh, David and Au, Alfred and Jablons, David M and You, Liang} } @article {230, title = {Knockdown of Cul4A increases chemosensitivity to gemcitabine through upregulation of TGFBI in lung cancer cells.}, journal = {Oncol Rep}, volume = {34}, year = {2015}, month = {2015 Dec}, pages = {3187-95}, abstract = {

Cullin 4A (Cul4A) promotes oncogenesis through overexpression and then ubiquitination-mediated proteolysis of tumor suppressors in various types of cancers. Transforming growth factor β-induced (TGFBI) has been implicated as a tumor suppressor, which enhances gemcitabine chemosensitivity in lung cancer cells. The present study aimed to investigate the association of TGFBI and Cul4A and the mechanism by which Cul4A regulates TGFBI. In addition, we also evaluated the therapeutic value of Cul4A RNAi using adenoviral transfection of Cul4A RNAi in nude mouse xenograft models. We observed that knockdown of Cul4A was associated with increased sensitivity to gemcitabine through upregulation of TGFBI in lung cancer cells. Cul4A regulated TGFBI through direct interaction and then ubiquitin-mediated protein degradation. In the nude mouse xenograft models, adenoviral transfection of Cul4A RNAi in combination with gemcitabine chemotherapy inhibited lung cancer tumor growth. As the result, combination of Cul4A RNAi with chemotherapy may provide a new approach to lung cancer treatment.

}, keywords = {Animals, Cell Line, Tumor, Cell Transformation, Neoplastic, Cullin Proteins, Deoxycytidine, Drug Resistance, Neoplasm, Extracellular Matrix Proteins, Gene Expression Regulation, Neoplastic, Gene Knockdown Techniques, Humans, Lung Neoplasms, Mice, Transforming Growth Factor beta, Xenograft Model Antitumor Assays}, issn = {1791-2431}, doi = {10.3892/or.2015.4324}, author = {Hung, Ming-Szu and Chen, I-Chuan and You, Liang and Jablons, David M and Li, Ya-Chin and Jiang-Hua Mao and Xu, Zhidong and Hsieh, Meng-Jer and Lin, Yu-Ching and Yang, Cheng-Ta and Liu, Shin-Tung and Tsai, Ying-Huang} } @article {208, title = {Lung tumourigenesis in a conditional Cul4A transgenic mouse model.}, journal = {J Pathol}, volume = {233}, year = {2014}, month = {2014 Jun}, pages = {113-23}, abstract = {

Cullin4A (Cul4A) is a scaffold protein that assembles cullin-RING ubiquitin ligase (E3) complexes and regulates many cellular events, including cell survival, development, growth and cell cycle control. Our previous study suggested that Cul4A is oncogenic in vitro, but its oncogenic role in vivo has not been studied. Here, we used a Cul4A transgenic mouse model to study the potential oncogenic role of Cul4A in lung tumour development. After Cul4A over-expression was induced in the lungs for 32 weeks, atypical epithelial cells were observed. After 40 weeks, lung tumours were visible and were characterized as grade I or II adenocarcinomas. Immunohistochemistry (IHC) revealed decreased levels of Cul4A-associated proteins p21(CIP1) and tumour suppressor p19(ARF) in the lung tumours, suggesting that Cul4A regulated their expression in these tumours. Increased levels of p27(KIP1) and p16(INK4a) were also detected in these tumours. Moreover, the protein level of DNA replication licensing factor CDT1 was decreased. Genomic instability in the lung tumours was further analysed by the results from pericentrin protein expression and array comparative genomic hybridization analysis. Furthermore, knocking down Cul4A expression in lung cancer H2170 cells increased their sensitivity to the chemotherapy drug cisplatin in vitro, suggesting that Cul4A over-expression is associated with cisplatin resistance in the cancer cells. Our findings indicate that Cul4A is oncogenic in vivo, and this Cul4A mouse model is a tool in understanding the mechanisms of Cul4A in human cancers and for testing experimental therapies targeting Cul4A.

}, keywords = {Adenocarcinoma, Animals, Antineoplastic Agents, Cell Cycle Proteins, Cell Line, Tumor, Cell Survival, Cell Transformation, Neoplastic, Cisplatin, Cullin Proteins, Cyclin-Dependent Kinase Inhibitor p16, Cyclin-Dependent Kinase Inhibitor p19, Cyclin-Dependent Kinase Inhibitor p21, Cyclin-Dependent Kinase Inhibitor p27, Disease Models, Animal, DNA-Binding Proteins, Dose-Response Relationship, Drug, Drug Resistance, Neoplasm, Gene Expression Regulation, Neoplastic, Genomic Instability, Humans, Lung, Lung Neoplasms, Mice, Mice, Transgenic, Neoplasm Grading, Proliferating Cell Nuclear Antigen, RNA Interference, Time Factors, Transfection, Up-Regulation}, issn = {1096-9896}, doi = {10.1002/path.4352}, author = {Yang, Yi-Lin and Hung, Ming-Szu and Wang, Yang and Ni, Jian and Jiang-Hua Mao and Hsieh, David and Au, Alfred and Kumar, Atul and Quigley, David and Fang, Li Tai and Yeh, Che-Chung and Xu, Zhidong and Jablons, David M and You, Liang} } @article {204, title = {Hematein, a casein kinase II inhibitor, inhibits lung cancer tumor growth in a murine xenograft model.}, journal = {Int J Oncol}, volume = {43}, year = {2013}, month = {2013 Nov}, pages = {1517-22}, abstract = {

Casein kinase II (CK2) inhibitors suppress cancer cell growth. In this study, we examined the inhibitory effects of a novel CK2 inhibitor, hematein, on tumor growth in a murine xenograft model. We found that in lung cancer cells, hematein inhibited cancer cell growth, Akt/PKB Ser129 phosphorylation, the Wnt/TCF pathway and increased apoptosis. In a murine xenograft model of lung cancer, hematein inhibited tumor growth without significant toxicity to the mice tested. Molecular docking showed that hematein binds to CK2α in durable binding sites. Collectively, our results suggest that hematein is an allosteric inhibitor of protein kinase CK2 and has antitumor activity to lung cancer.

}, keywords = {Animals, Apoptosis, Blotting, Western, Casein Kinase II, Enzyme Inhibitors, Female, Hematoxylin, Humans, Immunoenzyme Techniques, Lung Neoplasms, Mice, Mice, Inbred BALB C, Phosphorylation, Proto-Oncogene Proteins c-akt, T Cell Transcription Factor 1, Tumor Cells, Cultured, Wnt Proteins, Xenograft Model Antitumor Assays}, issn = {1791-2423}, doi = {10.3892/ijo.2013.2087}, author = {Hung, Ming-Szu and Xu, Zhidong and Chen, Yu and Smith, Emmanuel and Jiang-Hua Mao and Hsieh, David and Lin, Yu-Ching and Yang, Cheng-Ta and Jablons, David M and You, Liang} } @article {173, title = {Cul4A is an oncogene in malignant pleural mesothelioma.}, journal = {J Cell Mol Med}, volume = {15}, year = {2011}, month = {2011 Feb}, pages = {350-8}, abstract = {

Cullin 4A (Cul4A) is important in cell survival, development, growth and the cell cycle, but its role in mesothelioma has not been studied. For the first time, we identified amplification of the Cul4A gene in four of five mesothelioma cell lines. Consistent with increased Cul4A gene copy number, we found that Cul4A protein was overexpressed in mesothelioma cells as well. Cul4A protein was also overexpressed in 64\% of primary malignant pleural mesothelioma (MPM) tumours. Furthermore, knockdown of Cul4A with shRNA in mesothelioma cells resulted in up-regulation of p21 and p27 tumour suppressor proteins in a p53-independent manner in H290, H28 and MS-1 mesothelioma cell lines. Knockdown of Cul4A also resulted in G0/G1 cell cycle arrest and decreased colony formation in H290, H28 and MS-1 mesothelioma cell lines. Moreover, G0/G1 cell cycle arrest was partially reversed by siRNA down-regulation of p21 and/or p27 in Cul4A knockdown H290 cell line. In the contrary, overexpression of Cul4A resulted in down-regulation of p21 and p27 proteins and increased colony formation in H28 mesothelioma cell line. Both p21 and p27 showed faster degradation rates in Cul4A overexpressed H28 cell line and slower degradation rates in Cul4A knockdown H28 cell line. Our study indicates that Cul4A amplification and overexpression play an oncogenic role in the pathogenesis of mesothelioma. Thus, Cul4A may be a potential therapeutic target for MPM.

}, keywords = {Cell Cycle, Cell Line, Tumor, Cullin Proteins, Humans, Mesothelioma, Oncogenes, Pleural Neoplasms, Proliferating Cell Nuclear Antigen, rho GTP-Binding Proteins, RNA Interference, RNA, Small Interfering, Signal Transduction}, issn = {1582-4934}, doi = {10.1111/j.1582-4934.2009.00971.x}, author = {Hung, Ming-Szu and Jiang-Hua Mao and Xu, Zhidong and Yang, Cheng-Ta and Yu, Jau-Song and Harvard, Chansonette and Lin, Yu-Ching and Bravo, Dawn Therese and Jablons, David M and You, Liang} } @article {174, title = {Transgenic mice for cre-inducible overexpression of the Cul4A gene.}, journal = {Genesis}, volume = {49}, year = {2011}, month = {2011 Mar}, pages = {134-41}, abstract = {

The Cullin 4A(Cul4A) gene is important in cell survival, development, growth, and cell cycle control and is amplified in breast and hepatocellular cancers. Recently, we reported that Cul4A plays an oncogenic role in the pathogenesis of mesothelioma. An important strategy for studying Cul4A in different tissues is targeted overexpression of this gene in vivo. Studies of Cul4A in mice have been restricted to the loss-of-function studies using Cul4A knockout mice; gain-of-function studies of Cul4A using transgenic mice have not been reported. We, therefore, generated a gain-of-function transgenic mouse model that overexpresses Cul4A in a Cre-dependent manner. Before Cre recombination, these mice express LacZ during development in most adult tissues. After Cre-mediated excision of the LacZ reporter, the transfected Cul4A gene is expressed along with a C-terminal Myc-tag in different tissues. In this study, Cre-excision was induced in mouse lungs by inhalation of an adenovirus vector encoding Cre recombinase. This mouse model provides a valuable resource for investigating the significance of Cul4A overexpression in various tissues.

}, keywords = {Adenoviridae, Animals, Cullin Proteins, Gene Expression Regulation, Genes, Reporter, Genetic Vectors, Integrases, Lac Operon, Mice, Mice, Knockout, Mice, Transgenic, Models, Animal, Promoter Regions, Genetic, Recombination, Genetic, Transgenes}, issn = {1526-968X}, doi = {10.1002/dvg.20708}, author = {Li, Tong and Hung, Ming-Szu and Wang, Yucheng and Jiang-Hua Mao and Tan, Jia-Li and Jahan, Kenneth and Roos, Hannah and Xu, Zhidong and Jablons, David M and You, Liang} } @article {170, title = {Functional polymorphism of the CK2alpha intronless gene plays oncogenic roles in lung cancer.}, journal = {PLoS One}, volume = {5}, year = {2010}, month = {2010}, pages = {e11418}, abstract = {

Protein kinase CK2 is frequently up-regulated in human cancers, although the mechanism of CK2 activation in cancer remains unknown. In this study, we investigated the role of the CK2alpha intronless gene (CSNK2A1P, a presumed CK2alpha pseudogene) in the pathogenesis of human cancers. We found evidence of amplification and over-expression of the CSNK2A1P gene in non-small cell lung cancer and leukemia cell lines and 25\% of the lung cancer tissues studied. The mRNA expression levels correlated with the copy numbers of the CSNK2A1P gene. We also identified a novel polymorphic variant (398T/C, I133T) of the CSNK2A1P gene and showed that the 398T allele is selectively amplified over the 398C allele in 101 non-small cell lung cancer tissue samples compared to those in 48 normal controls (p = 0.013<0.05). We show for the first time CSNK2A1P protein expression in transfected human embryonic kidney 293T and mouse embryonic fibroblast NIH-3T3 cell lines. Both alleles are transforming in these cell lines, and the 398T allele appears to be more transforming than the 398C allele. Moreover, the 398T allele degrades PML tumor suppressor protein more efficiently than the 398C allele and shows a relatively stronger binding to PML. Knockdown of the CSNK2A1P gene expression with specific siRNA increased the PML protein level in lung cancer cells. We report, for the first time, that the CSNK2A1P gene is a functional proto-oncogene in human cancers and its functional polymorphism appears to degrade PML differentially in cancer cells. These results are consistent with an important role for the 398T allele of the CSNK2A1P in human lung cancer susceptibility.

}, keywords = {Animals, Blotting, Western, Casein Kinase II, Cell Line, Cell Line, Tumor, Gene Expression Regulation, Neoplastic, Humans, Immunoprecipitation, In Situ Hybridization, Fluorescence, In Vitro Techniques, Lung Neoplasms, Mice, NIH 3T3 Cells, Nuclear Proteins, Polymorphism, Genetic, Protein Binding, Reverse Transcriptase Polymerase Chain Reaction, RNA, Small Interfering, Sequence Analysis, DNA, Transcription Factors, Tumor Suppressor Proteins}, issn = {1932-6203}, doi = {10.1371/journal.pone.0011418}, author = {Hung, Ming-Szu and Lin, Yu-Ching and Jiang-Hua Mao and Kim, Il-Jin and Xu, Zhidong and Yang, Cheng-Ta and Jablons, David M and You, Liang} } @article {166, title = {Identification of hematein as a novel inhibitor of protein kinase CK2 from a natural product library.}, journal = {BMC Cancer}, volume = {9}, year = {2009}, month = {2009}, pages = {135}, abstract = {

BACKGROUND: Casein kinase 2 (CK2) is dysregulated in various human cancers and is a promising target for cancer therapy. To date, there is no small molecular CK2 inhibitor in clinical trial yet. With the aim to identify novel CK2 inhibitors, we screened a natural product library.

METHODS: We adopted cell-based proliferation and CK2 kinase assays to screen CK2 inhibitors from a natural compound library. Dose-dependent response of CK2 inhibitors in vitro was determined by a radioisotope kinase assay. Western blot analysis was used to evaluate down stream Akt phosphorylation and apoptosis. Apoptosis was also evaluated by annexin-V/propidium iodide (PI) labeling method using flow cytometry. Inhibition effects of CK2 inhibitors on the growth of cancer and normal cells were evaluated by cell proliferation and viability assays.

RESULTS: Hematein was identified as a novel CK2 inhibitor that is highly selective among a panel of kinases. It appears to be an ATP non-competitive and partially reversible CK2 inhibitor with an IC50 value of 0.55 muM. In addition, hematein inhibited cancer cell growth partially through down-regulation of Akt phosphorylation and induced apoptosis in these cells. Furthermore, hematein exerted stronger inhibition effects on the growth of cancer cells than in normal cells.

CONCLUSION: In this study, we showed that hematein is a novel selective and cell permeable small molecule CK2 inhibitor. Hematein showed stronger growth inhibition effects to cancer cells when compared to normal cells. This compound may represent a promising class of CK2 inhibitors.

}, keywords = {Adenosine Triphosphate, Apoptosis, Casein Kinase II, Cell Growth Processes, Cell Line, Tumor, Dose-Response Relationship, Drug, HCT116 Cells, HeLa Cells, Hematoxylin, Humans, Lung Neoplasms, Neoplasms, Protein Kinase Inhibitors, Proto-Oncogene Proteins c-akt, Substrate Specificity}, issn = {1471-2407}, doi = {10.1186/1471-2407-9-135}, author = {Hung, Ming-Szu and Xu, Zhidong and Lin, Yu-Ching and Jiang-Hua Mao and Yang, Cheng-Ta and Chang, Pey-Jium and Jablons, David M and You, Liang} }