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Characterization of ARF-BP1/HUWE1 Interactions with CTCF, MYC, ARF and p53 in MYC-Driven B Cell Neoplasms  [PDF]
Chen-Feng Qi,Yong-Soo Kim,Shao Xiang,Ziedulla Abdullaev,Ted A. Torrey,Siegfried Janz,Alexander L. Kovalchuk,Jiafang Sun,Delin Chen,William C. Cho,Wei Gu,Herbert C. Morse III
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms13056204
Abstract: Transcriptional activation of MYC is a hallmark of many B cell lineage neoplasms. MYC provides a constitutive proliferative signal but can also initiate ARF-dependent activation of p53 and apoptosis. The E3 ubiquitin ligase, ARF-BP1, encoded by HUWE1, modulates the activity of both the MYC and the ARF-p53 signaling pathways, prompting us to determine if it is involved in the pathogenesis of MYC-driven B cell lymphomas. ARF-BP1 was expressed at high levels in cell lines from lymphomas with either wild type or mutated p53 but not in ARF-deficient cells. Downregulation of ARF-BP1 resulted in elevated steady state levels of p53, growth arrest and apoptosis. Co-immunoprecipitation studies identified a multiprotein complex comprised of ARF-BP1, ARF, p53, MYC and the multifunctional DNA-binding factor, CTCF, which is involved in the transcriptional regulation of MYC, p53 and ARF. ARF-BP1 bound and ubiquitylated CTCF leading to its proteasomal degradation. ARF-BP1 and CTCF thus appear to be key cofactors linking the MYC proliferative and p53-ARF apoptotic pathways. In addition, ARF-BP1 could be a therapeutic target for MYC-driven B lineage neoplasms, even if p53 is inactive, with inhibition reducing the transcriptional activity of MYC for its target genes and stabilizing the apoptosis-promoting activities of p53.
Triterpenoids Display Single Agent Anti-tumor Activity in a Transgenic Mouse Model of Chronic Lymphocytic Leukemia and Small B Cell Lymphoma  [PDF]
Christina L. Kress, Marina Konopleva, Vanesa Martínez-García, Maryla Krajewska, Sophie Lefebvre, Marc L. Hyer, Teresa McQueen, Michael Andreeff, John C. Reed, Juan M. Zapata
PLOS ONE , 2007, DOI: 10.1371/journal.pone.0000559
Abstract: Background The synthetic triterpenoid 2-Cyano-3,12-Dioxooleana-1,9-Dien-28-Oic Acid (CDDO) and derivatives display anti-tumor activity against a variety of cultured tumor cell lines and in mouse xenografts. In this report, we have studied the effects of CDDO and its imidazolide derivative (CDDO-Im) on chronic lymphocytic leukemia (CLL), using patients' CLL cells and a mouse model of CLL and small B cell lymphoma (SBL). Principal Findings CDDO and CDDO-Im efficiently induced apoptosis of malignant human and mouse B-cells ex vivo, although CDDO-Im was over 10-fold more potent than CDDO. Treating mice with CLL/SBL with liposome-formulated CDDO or CDDO-Im resulted in significant reductions of B cells in blood, spleen and lung. CDDO-Im was shown to be more potent than CDDO, while treatment with empty liposomes had no impact on disease. CDDO-Im treatment initially resulted in an increase of circulating B cells, which correlates with a reduction in resident lymphocytes in spleen, and lungs, suggesting that CDDO-Im induces mobilization of tumor cells from lymphoid organs and infiltrated tissues into the circulation. Analysis of blood cells recovered from treated mice also showed that CDDO-Im is a potent inducer of tumor cells death in vivo. Furthermore, CDDO-Im efficiently eradicated mouse CLL/SBL cells but had little effect on the viability of normal B and T cells in vivo. Significance The presented data demonstrate that triterpenoids CDDO and CDDO-Im reduce leukemia and lymphoma burden in vivo in a transgenic mouse model of CLL/SBL, and support the clinical testing of CDDO-based synthetic triterpenoids in patients with CLL.
新型CDDO衍生物的合成及抗肿瘤活性  [PDF]
- , 2017,
Abstract: 对2-氰基-3,12-二氧代齐墩果烷-1,9(11)-二烯-28-羧酸(CDDO)进行结构修饰,通过不同连接臂将几种含氮杂环分别引入C-17位羧基,设计并合成了12个未见文献报道的新化合物(9a~9l),其结构经ESI-MS、IR和1H NMR确认。采用MTT法评价了化合物对HCT-116、A549及HepG2肿瘤细胞的抑制活性。实验结果表明,部分化合物对肿瘤细胞具有较强的抑制活性,其中化合物9c的活性最强,高于CDDO咪唑啉酮衍生物(CDDO-Im)。血浆稳定性实验表明,化合物9c的血浆稳定性较高,显著高于CDDO-Im。
Twelve novel 2-cyano-3, 12-dioxooleana-1, 9(11)-dien-28-oic acid(CDDO)derivatives were designed and synthesized(9a-9l)by introducing different heterocyclic rings to 17-COOH of CDDO through various linkers. Their structures were determined by ESI-MS, IR and 1H NMR. The antiproliferative activity of the synthetic derivatives against human cancer cells HCT-116, A549 and HepG2 was evaluated by MTT assay. Several compounds showed potent inhibitory activities against test cell lines. Among them, compound 9c showed more potent antiproliferative activity than the CDDO-imidazolide(CDDO-Im). Moreover, rat plasma stability assay showed that compound 9c was more stable than CDDO-Im
Inhibition of Telomerase Activity by Oleanane Triterpenoid CDDO-Me in Pancreatic Cancer Cells is ROS-Dependent  [PDF]
Dorrah Deeb,Xiaohua Gao,Yongbo Liu,Nadimpalli R. S. Varma,Ali S. Arbab,Subhash C. Gautam
Molecules , 2013, DOI: 10.3390/molecules18033250
Abstract: Methyl-2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oate (CDDO-Me) is a synthetic derivative of oleanolic acid, a triterpene, with apoptosis-inducing activity in a wide range of cancer cells. Induction of apoptosis by CDDO-Me is associated with the generation of reactive oxygen species (ROS) and inhibition of telomerase activity. In the present study, we investigated the role of ROS in inhibition of telomerase by CDDO-me. Treatment of MiaPaCa-2 and Panc-1 pancreatic cancer cell lines with CDDO-Me induced the production of hydrogen peroxide and superoxide anions and inhibited the telomerase activity. Pretreatment of cells with N-acetylcycsteine, a general purpose antioxidant or overexpression of glutathione peroxidase (GPx) or superoxide dismutase-1 (SOD-1) blocked the telomerase inhibitory activity of CDDO-Me. Furthermore, blocking ROS generation also prevented the inhibition of hTERT gene expression, hTERT protein production and expression of a number of hTERT–regulatory proteins by CDDO-Me (e.g., c-Myc, Sp1, NF-κB and p-Akt). Data also showed that Akt plays an important role in the activation of telomerase activity. Together, these data suggest that inhibition of telomerase activity by CDDO-Me is mediated through a ROS-dependent mechanism; however, more work is needed to fully understand the role of ROS in down-regulation of hTERT gene and hTERT-regulatory proteins by CDDO-Me.
Telomerase Reverse Transcriptase (TERT) is a Therapeutic Target of Oleanane Triterpenoid CDDO-Me in Prostate Cancer  [PDF]
Yongbo Liu,Xiaohua Gao,Dorrah Deeb,Ali S. Arbab,Subhash C. Gautam
Molecules , 2012, DOI: 10.3390/molecules171214795
Abstract: Methyl-2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oate (CDDO-Me) is an synthetic oleanane triterpenoid with strong antiprolifertive and proapoptotic activities in cancer cells. However, the effect of CDDO-Me on human telomerase reverse transcriptase (hTERT) and its telomerase activity in prostate cancer cells has not been studied. We investigated the role of hTERT in mediating the anticancer activity of CDDO-Me in prostate cancer cells in vitro and in vivo. The inhibition of cell proliferation and induction of apoptosis by CDDO-Me in LNCaP and PC-3 prostate cancer cell lines was associated with the inhibition of hTERT gene expression, hTERT telomerase activity and a number of proteins that regulate hTERT transcriptionally and post-translationally. Furthermore, ablation of hTERT protein increased the sensitivity of cancer cells to CDDO-Me, whereas its overexpression rendered them resistant to CDDO-Me. In addition, inhibition of progression of preneoplastic lesions (i.e., low and high-grade prostate intraepithelial neoplasms, PINs) to adenocarcinoma of the prostate by CDDO-Me in TRAMP mice was associated with significant decrease in TERT and its regulatory proteins in the prostate gland. These data provide evidence that telomerase is a potential target of CDDO-Me for the prevention and treatment of prostate cancer.
RNA interference-mediated c-MYC inhibition prevents cell growth and decreases sensitivity to radio- and chemotherapy in childhood medulloblastoma cells
André O von Bueren, Tarek Shalaby, Christoph Oehler-J?nne, Lucia Arnold, Duncan Stearns, Charles G Eberhart, Alexandre Arcaro, Martin Pruschy, Michael A Grotzer
BMC Cancer , 2009, DOI: 10.1186/1471-2407-9-10
Abstract: To study the role of c-MYC in MB biology, we down-regulated c-MYC expression by using small interfering RNA (siRNA) and investigated changes in cellular proliferation, cell cycle analysis, apoptosis, telomere maintenance, and response to ionizing radiation (IR) and chemotherapeutics in a representative panel of human MB cell lines expressing different levels of c-MYC (DAOY wild-type, DAOY transfected with the empty vector, DAOY transfected with c-MYC, D341, and D425).siRNA-mediated c-MYC down-regulation resulted in an inhibition of cellular proliferation and clonogenic growth, inhibition of G1-S phase cell cycle progression, and a decrease in human telomerase reverse transcriptase (hTERT) expression and telomerase activity. On the other hand, down-regulation of c-MYC reduced apoptosis and decreased the sensitivity of human MB cells to IR, cisplatin, and etoposide. This effect was more pronounced in DAOY cells expressing high levels of c-MYC when compared with DAOY wild-type or DAOY cells transfected with the empty vector.In human MB cells, in addition to its roles in growth and proliferation, c-MYC is also a potent inducer of apoptosis. Therefore, targeting c-MYC might be of therapeutic benefit when used sequentially with chemo- and radiotherapy rather than concomitantly.Medulloblastomas (MB) are the most common malignant pediatric neoplasms of the central nervous system. MB constitute 20% of all pediatric brain tumors [1] and are characterized by their aggressive clinical behavior and a high risk of leptomeningeal dissemination. With current treatment strategies, nearly half of all patients eventually die from progressive tumors. Accordingly, the identification of novel therapeutic strategies remains a major goal.The c-MYC proto-oncogene encodes a nuclear phosphoprotein involved in the transcription of genes central to regulating the cell cycle [2-4], proliferation [5,6], apoptosis [7-9], telomere maintenance [10,11], angiogenesis [12], and differentiation [13]. Th
Proteotypic classification of spontaneous and transgenic mammary neoplasms
Igor Mikaelian, Natalie Blades, Gary A Churchill, Karen Fancher, Barbara B Knowles, Janan T Eppig, John P Sundberg
Breast Cancer Research , 2004, DOI: 10.1186/bcr930
Abstract: Expression patterns for terminal differentiation markers were used to characterize tumor types and to study tumor progression in transgenic mouse models of mammary neoplasia (mice overexpressing Neu (Erbb2), Hras, Myc, Notch4, SV40-TAg, Tgfa, and Wnt1), in spontaneous mammary carcinomas, and in mammary neoplasms associated with infection by the mouse mammary tumor virus (MMTV).On the basis of the expression of terminal differentiation markers, three types of neoplasm were identified: first, simple carcinomas composed exclusively of cells with a luminal phenotype are characteristic of neoplasms arising in mice transgenic for Neu, Hras, Myc, Notch4, and SV40-TAg; second, 'complex carcinomas' displaying luminal and myoepithelial differentiation are characteristic of type P tumors arising in mice transgenic for Wnt1, neoplasms arising in mice infected by the MMTV, and spontaneous adenosquamous carcinomas; and third, 'carcinomas with epithelial to mesenchymal transition (EMT)' are a characteristic feature of tumor progression in Hras-, Myc-, and SV40-TAg-induced mammary neoplasms and PL/J and SJL/J mouse strains, and display de novo expression of myoepithelial and mesenchymal cell markers. In sharp contrast, EMT was not detected in papillary adenocarcinomas arising in BALB/cJ mice, spontaneous adenoacanthomas, neoplasms associated with MMTV-infection, or in neoplasms arising in mice transgenic for Neu and Wnt1.Immunohistochemical profiles of complex neoplasms are consistent with a stem cell origin, whereas simple carcinomas might originate from a cell committed to the luminal lineage. In addition, these results suggest that the initiating oncogenic events determine the morphologic features associated with cancer progression because EMT is observed only in certain types of neoplasm.Architectural and cytological patterns have been the basis for mammary tumor categorization for more than a century [1]. Over the past 20 years, immunohistochemistry has added a molecular dimen
c-myc Regulates Cell Proliferation during Lens Development  [PDF]
Gabriel R. Cavalheiro, Gabriel E. Matos-Rodrigues, Anielle L. Gomes, Paulo M. G. Rodrigues, Rodrigo A. P. Martins
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0087182
Abstract: Myc protooncogenes play important roles in the regulation of cell proliferation, growth, differentiation and survival during development. In various developing organs, c-myc has been shown to control the expression of cell cycle regulators and its misregulated expression is detected in many human tumors. Here, we show that c-myc gene (Myc) is highly expressed in developing mouse lens. Targeted deletion of c-myc gene from head surface ectoderm dramatically impaired ocular organogenesis, resulting in severe microphtalmia, defective anterior segment development, formation of a lens stalk and/or aphakia. In particular, lenses lacking c-myc presented thinner epithelial cell layer and growth impairment that was detectable soon after its inactivation. Defective development of c-myc-null lens was not caused by increased cell death of lens progenitor cells. Instead, c-myc loss reduced cell proliferation, what was associated with an ectopic expression of Prox1 and p27Kip1 proteins within epithelial cells. Interestingly, a sharp decrease in the expression of the forkhead box transcription factor Foxe3 was also observed following c-myc inactivation. These data represent the first description of the physiological roles played by a Myc family member in mouse lens development. Our findings support the conclusion that c-myc regulates the proliferation of lens epithelial cells in vivo and may, directly or indirectly, modulate the expression of classical cell cycle regulators in developing mouse lens.
CDDO-Me: A Novel Synthetic Triterpenoid for the Treatment of Pancreatic Cancer  [PDF]
Dorrah Deeb,Xiaohua Gao,Ali S. Arbab,Kenneth Barton,Scott A. Dulchavsky,Subhash C. Gautam
Cancers , 2010, DOI: 10.3390/cancers2041779
Abstract: Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal human malignancy with dismal prognosis and few effective therapeutic options. Novel agents that are safe and effective are urgently needed. Oleanolic acid-derived synthetic triterpenoids are potent antitumorigenic agents, but their efficacy or the mechanism of action for pancreatic cancer has not been adequately investigated. In this study, we evaluated the antitumor activity and the mechanism of action of methyl-2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oate (CDDO-Me), a oleanane-derived synthetic triterpenoid for human pancreatic cancer cell lines. CDDO-Me inhibited the growth of both K-ras mutated (MiaPaca2, Panc1 and Capan2) and wild-type K-ras (BxPC3) pancreatic cancer cells at very low concentrations. The growth inhibitory activity of CDDO-Me was attributed to the induction of apoptosis characterized by increased annexin-V-FITC binding and cleavage of PARP-1 and procaspases-3, -8 and-9. In addition, CDDO-Me induced the loss of mitochondrial membrane potential and release of cytochrome C. The antitumor activity of CDDO-Me was associated with the inhibition of prosurvival p-Akt, NF-κB and mammalian target of rapamycin (mTOR) signaling proteins and the downstream targets of Akt and mTOR, such as p-Foxo3a (Akt) and p-S6K1, p-eIF-4E and p-4E-BP1 (mTOR). Silencing of Akt or mTOR with gene specific-siRNA sensitized the pancreatic cancer cells to CDDO-Me, demonstrating Akt and mTOR as molecular targets of CDDO-Me for its growth inhibitory and apoptosis-inducing activity.
Prevention of Prostate Cancer with Oleanane Synthetic Triterpenoid CDDO-Me in the TRAMP Mouse Model of Prostate Cancer  [PDF]
Xiaohua Gao,Dorrah Deeb,Yongbo Liu,Ali S. Arbab,George W. Divine,Scott A. Dulchavsky,Subhash C. Gautam
Cancers , 2011, DOI: 10.3390/cancers3033353
Abstract: 2-Cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO), a synthetic analog of oleanolic acid, and its C28 methyl ester derivative (CDDO-Me), have shown potent antitumorigenic activity against a wide range of cancer cell lines, including prostate cancer cells in vitro, and inhibited the development of liver and lung cancer in vivo. In the present study, we examined the efficacy of CDDO-Me in preventing the development and progression of prostate cancer in the transgenic adenocarinoma of the mouse prostate (TRAMP) model. CDDO-Me inhibited the growth of murine TRAMPC-1 prostate cancer cells by inducing apoptosis through the inhibition of antiapoptotic p-Akt, p-mTOR and NF-κB. Early intervention with CDDO-Me (7.5 mg/kg) initiated at five weeks of age for 20 wk inhibited the progression of the preneoplastic lesions (low-grade PIN and high-grade-PIN) to adenocarcinoma in the dorsolateral prostate (DLP) and ventral prostate (VP) lobes of TRAMP mice. Even delayed administration of CDDO-Me started at 12 wk of age for 12 wk inhibited the development of adenocarcimona of the prostate. Both early and late treatment with CDDO-Me inhibited the metastasis of tumor to the distant organs. Treatment with CDDO-Me inhibited the expression of prosurvival p-Akt and NF-κB in the prostate and knocking-down Akt in TRAMPC-1 tumor cells sensitized them to CDDO-Me. These findings indicated that Akt is a target for apoptoxicity in TRAMPC-1 cells in vitro and potentially a target of CDDO-Me for inhibition of prostate cancer in vivo.
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