The Triterpenoid 2-Cyano-3,12-dioxooleana-1,9-dien-28-oic-acid Methyl Ester Has Potent Anti-diabetic Effects in Diet-induced Diabetic Mice and Lepr Mice
2010; Elsevier BV; Volume: 285; Issue: 52 Linguagem: Inglês
10.1074/jbc.m110.176545
ISSN1083-351X
AutoresPradip Saha, Vasumathi T. Reddy, Marina Konopleva, Michael Andreeff, Lawrence Chan,
Tópico(s)Genomics, phytochemicals, and oxidative stress
ResumoThe triterpenoid 2-Cyano-3,12-dioxooleana-1,9-dien-28-oic-acid (CDDO) and its methyl ester (CDDO-Me) are undergoing clinical trials in cancer and leukemia therapy. Here we report that CDDO-Me ameliorates diabetes in high fat diet-fed type 2 diabetic mice and in Leprdb/db mice. CDDO-Me reduces proinflammatory cytokine expression in these animals. Oral CDDO-Me administration reduces total body fat, plasma triglyceride, and free fatty acid levels. It also improves glucose tolerance and insulin tolerance tests. Its potent glucose-lowering activity results from enhanced insulin action. Hyperinsulinemic-euglycemic clamp reveals an increased glucose infusion rate required to maintain euglycemia and showed a significant increase in muscle-specific insulin-stimulated glucose uptake (71% soleus, 58% gastrocnemius) and peripheral glucose clearance as documented by a 48% increase in glucose disposal rate. CDDO-Me activates AMP-activated protein kinase (AMPK) and via LKB1 activation in muscle and liver in vivo. Treatment of isolated hepatocytes with CDDO-Me directly stimulates AMPK activity and LKB1 phosphorylation and decreases acetyl-coA carboxylase activity; it also down-regulates lipogenic gene expression, suppresses gluconeogenesis, and increases glucose uptake. Inhibition of AMPK phosphorylation using compound C and lentiviral-mediated knockdown of AMPK completely blocks the CDDO-Me-induced effect on hepatocytes as well as C2C12 cells. We conclude that the triterpenoid CDDO-Me has potent anti-diabetic action in diabetic mouse models that is mediated at least in part through AMPK activation. The in vivo anti-diabetogenic effects occur at a dose substantially lower than that used for anti-leukemia therapy. We suggest that CDDO-Me holds promise as a potential anti-diabetic agent. The triterpenoid 2-Cyano-3,12-dioxooleana-1,9-dien-28-oic-acid (CDDO) and its methyl ester (CDDO-Me) are undergoing clinical trials in cancer and leukemia therapy. Here we report that CDDO-Me ameliorates diabetes in high fat diet-fed type 2 diabetic mice and in Leprdb/db mice. CDDO-Me reduces proinflammatory cytokine expression in these animals. Oral CDDO-Me administration reduces total body fat, plasma triglyceride, and free fatty acid levels. It also improves glucose tolerance and insulin tolerance tests. Its potent glucose-lowering activity results from enhanced insulin action. Hyperinsulinemic-euglycemic clamp reveals an increased glucose infusion rate required to maintain euglycemia and showed a significant increase in muscle-specific insulin-stimulated glucose uptake (71% soleus, 58% gastrocnemius) and peripheral glucose clearance as documented by a 48% increase in glucose disposal rate. CDDO-Me activates AMP-activated protein kinase (AMPK) and via LKB1 activation in muscle and liver in vivo. Treatment of isolated hepatocytes with CDDO-Me directly stimulates AMPK activity and LKB1 phosphorylation and decreases acetyl-coA carboxylase activity; it also down-regulates lipogenic gene expression, suppresses gluconeogenesis, and increases glucose uptake. Inhibition of AMPK phosphorylation using compound C and lentiviral-mediated knockdown of AMPK completely blocks the CDDO-Me-induced effect on hepatocytes as well as C2C12 cells. We conclude that the triterpenoid CDDO-Me has potent anti-diabetic action in diabetic mouse models that is mediated at least in part through AMPK activation. The in vivo anti-diabetogenic effects occur at a dose substantially lower than that used for anti-leukemia therapy. We suggest that CDDO-Me holds promise as a potential anti-diabetic agent. IntroductionTriterpenoids, together with their close relatives, the steroids, are members of the cyclosqualenoid family (1Sporn M.B. Suh N. Carcinogenesis. 2000; 21: 525-530Crossref PubMed Scopus (439) Google Scholar). The semisynthetic triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO) 2The abbreviations used are: CDDO2-cyano-3,12-dioxooleana-1,9-dien-28-oic-acidCDDO-MeCDDO methyl esterAMPKAMP-activated protein kinaseACCacetyl-coA carboxylaseFFAfree fatty acidGTTglucose tolerance testITTinsulin tolerance testIRinsulin receptorAICAR5-amino-imidazole carboxamide ribosideWATwhite adipose tissueFASfatty acid synthaseSREBPsterol response element-binding proteinComp CCompound CPEPCKphosphoenolpyruvate carboxykinaseTGtriglycerideT2DMtype 2 diabetes mellitus. is structurally related to the pentacyclic triterpenoids oleanolic and ursolic acids. Studies with CDDO have revealed potent cellular differentiating, antiproliferative, proapoptotic (2Wang Y. Porter W.W. Suh N. Honda T. Gribble G.W. Leesnitzer L.M. Plunket K.D. Mangelsdorf D.J. Blanchard S.G. Willson T.M. Sporn M.B. Mol. Endocrinol. 2000; 14: 1550-1556Crossref PubMed Google Scholar), anti-inflammatory, and anticarcinogenic activities (3Huang M.T. Ho C.T. Wang Z.Y. Ferraro T. Lou Y.R. Stauber K. Ma W. Georgiadis C. Laskin J.D. Conney A.H. Cancer Res. 1994; 54: 701-708PubMed Google Scholar, 4Nishino H. Nishino A. Takayasu J. Hasegawa T. Iwashima A. Hirabayashi K. Iwata S. Shibata S. Cancer Res. 1988; 48: 5210-5215PubMed Google Scholar, 5Suh N. Honda T. Finlay H.J. Barchowsky A. Williams C. Benoit N.E. Xie Q.W. Nathan C. Gribble G.W. Sporn M.B. Cancer Res. 1998; 58: 717-723PubMed Google Scholar). This triterpenoid has been shown to induce monocytic differentiation of human myeloid leukemia cells, adipogenic differentiation of mouse 3T3-L1 fibroblasts, and nerve growth factor-induced neuronal differentiation of rat PC12 cells (6Suh N. Wang Y. Honda T. Gribble G.W. Dmitrovsky E. Hickey W.F. Maue R.A. Place A.E. Porter D.M. Spinella M.J. Williams C.R. Wu G. Dannenberg A.J. Flanders K.C. Letterio J.J. Mangelsdorf D.J. Nathan C.F. Nguyen L. Porter W.W. Ren R.F. Roberts A.B. Roche N.S. Subbaramaiah K. Sporn M.B. Cancer Res. 1999; 59: 336-341PubMed Google Scholar). CDDO enhanced the differentiation of acute promyelocytic leukemia cells in vitro and induced differentiation of all -trans retinoic acid-resistant acute promyelocytic leukemia cells (7Tabe Y. Konopleva M. Kondo Y. Contractor R. Tsao T. Konoplev S. Shi Y. Ling X. Watt J.C. Tsutsumi-Ishii Y. Ohsaka A. Nagaoka I. Issa J.P. Kogan S.C. Andreeff M. Cancer Biol. Ther. 2007; 6: 1967-1977Crossref PubMed Scopus (28) Google Scholar). The mechanism responsible for the differentiating action of CDDO was in part associated with activation of CEBP-β (8Koschmieder S. D'Alò F. Radomska H. Schöneich C. Chang J.S. Konopleva M. Kobayashi S. Levantini E. Suh N. Di Ruscio A. Voso M.T. Watt J.C. Santhanam R. Sargin B. Kantarjian H. Andreeff M. Sporn M.B. Perrotti D. Berdel W.E. Müller-Tidow C. Serve H. Tenen D.G. Blood. 2007; 110: 3695-3705Crossref PubMed Scopus (44) Google Scholar). Micromolar concentrations of CDDO have been observed to induce apoptosis in different cancer cell lines (9Gao X. Deeb D. Jiang H. Liu Y. Dulchavsky S.A. Gautam S.C. J. Neurooncol. 2007; 84: 147-157Crossref PubMed Scopus (85) Google Scholar, 10Hyer M.L. Shi R. Krajewska M. Meyer C. Lebedeva I.V. Fisher P.B. Reed J.C. Cancer Res. 2008; 68: 2927-2933Crossref PubMed Scopus (59) Google Scholar, 11Ikeda T. Nakata Y. Kimura F. Sato K. Anderson K. Motoyoshi K. Sporn M. Kufe D. Mol. Cancer Ther. 2004; 3: 39-45PubMed Google Scholar). CDDO inhibited the growth of several ovarian cancer cell lines that express peroxisome proliferator-activated receptor γ, but co-treatment with the peroxisome proliferator-activated receptor γ antagonist T007 did not block the apoptogenic effects of CDDO, suggesting a peroxisome proliferator-activated receptor γ-independent action (12Kodera Y. Takeyama K. Murayama A. Suzawa M. Masuhiro Y. Kato S. J. Biol. Chem. 2000; 275: 33201-33204Abstract Full Text Full Text PDF PubMed Scopus (182) Google Scholar, 13Melichar B. Konopleva M. Hu W. Melicharova K. Andreeff M. Freedman R.S. Gynecol. Oncol. 2004; 93: 149-154Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar).The C-28 methyl ester of CDDO, CDDO-Me, has been shown to decrease the viability of leukemic cell lines, including multidrug resistance 1-overexpressing cells (14Konopleva M. Tsao T. Ruvolo P. Stiouf I. Estrov Z. Leysath C.E. Zhao S. Harris D. Chang S. Jackson C.E. Munsell M. Suh N. Gribble G. Honda T. May W.S. Sporn M.B. Andreeff M. Blood. 2002; 99: 326-335Crossref PubMed Scopus (169) Google Scholar). It has been suggested that the combination of antitumorigenic, antiangiogenic, and proapoptotic effects and the ability of CDDO-Me to suppress cyclooxygenase 2 (COX-2), inducible nitric-oxide synthase, multidrug resistance gene 1, and FLIP is mediated by NF-κB activation through suppression of IκBα kinase (15Shishodia S. Sethi G. Konopleva M. Andreeff M. Aggarwal B.B. Clin. Cancer Res. 2006; 12: 1828-1838Crossref PubMed Scopus (146) Google Scholar). CDDO and CDDO-Me have shown differentiating effects in a clinical phase I study in acute myeloblastic leukemic patients and anti-tumor effects in solid tumors, alone and in combination with chemotherapy (8Koschmieder S. D'Alò F. Radomska H. Schöneich C. Chang J.S. Konopleva M. Kobayashi S. Levantini E. Suh N. Di Ruscio A. Voso M.T. Watt J.C. Santhanam R. Sargin B. Kantarjian H. Andreeff M. Sporn M.B. Perrotti D. Berdel W.E. Müller-Tidow C. Serve H. Tenen D.G. Blood. 2007; 110: 3695-3705Crossref PubMed Scopus (44) Google Scholar, 16Hong, D. S., Kurzrock, R., Supko, J. G., Lawrence, D. P., Wheler, J. J., Meyer, C. J., Mier, J. W., Andreeff, M., Shapiro, G. I., Dezube, B. J. (2008) American Society of Clinical Oncology (ASCO) Annual Meeting 2008, May 30–June 3, Chicago, IL.Google Scholar). The experimental drugs appear to have little toxic side effects at the doses used. We hypothesized that CDDO-Me may have beneficial action in diabetes and investigated its potential anti-diabetic effects and possible mode of action in mouse models of type 2 diabetes.DISCUSSIONThis study is the first detailed metabolic analysis of T2DM mice treated with CDDO-Me, an agent currently in phase I clinical trials in cancer patients. Our data showed that CDDO-Me treatment greatly attenuates the hyperglycemia of diet-induced T2DM mice. Euglycemic-hyperinsulinemic clamp experiments indicate that an increased rate of glucose infusion is required to maintain euglycemia in CDDO-Me-treated mice, indicating increased glucose disposal in peripheral tissues (mainly skeletal muscle). Therefore, the improvement of the diabetic state appears to be the result of improved insulin sensitivity in skeletal muscle, whereas hepatic glucose production remains relatively unchanged. Interestingly, in Leprdb/db mice, a genetic T2DM model, we found significant reduction in basal glucose production measured by a steady state infusion method in CDDO-Me-liposome-treated as compared with empty liposome-treated mice. We believe that in diet-induced diabetic mice in which the CDDO-Me was administered by gavage, we could have missed a mild to moderate decrease in hepatic glucose production, because for 4 days after jugular vein catheterization, we had to temporarily suspend the gavage for technical reasons. Even then, we observed in these diet-induced diabetic mice that 2 weeks of drug treatment restored euglycemia and reduced plasma insulin levels (random (Fig. 1D) as well as during GTT (Fig. 1F)). Increased phosphorylation of IRS-1 and IRS-2 (Fig. 2E) in the setting of a constant insulin infusion suggests enhanced signaling at a proximal step in the insulin signaling pathway.In addition to reversal of hyperglycemia, CDDO-Me treatment of diet-induced T2DM mice has a beneficial effect on all of these other comorbid conditions, i.e. it reverses obesity and insulin resistance, lowers TG and FFA, whereas it down-regulates the expression of a number of proinflammatory cytokines (35Yang J. Park Y. Zhang H. Xu X. Laine G.A. Dellsperger K.C. Zhang C. Am. J. Physiol. Heart Circ. Physiol. 2009; 296: H1850-H1858Crossref PubMed Scopus (92) Google Scholar) (Fig. 3, A and B). CDDO-Me has been reported to act on multiple targets (1Sporn M.B. Suh N. Carcinogenesis. 2000; 21: 525-530Crossref PubMed Scopus (439) Google Scholar), including inhibition of NF-κB-mediated gene expression after translocation of activated NF-κB to the nucleus. CDDO was found to abolish NF-κB-dependent resynthesis of IκBα, which suggests that CDDO-Me targets a step downstream of NF-κB translocation into the nucleus (36Stadheim T.A. Xiao H. Eastman A. Cancer Res. 2001; 61: 1533-1540PubMed Google Scholar). Our data are consistent with such an interpretation. In this study we also showed that this drug reduces lipogenesis in T2D mice, which corroborates a recent report by Shin et al. (37Shin S. Wakabayashi J. Yates M.S. Wakabayashi N. Dolan P.M. Aja S. Liby K.T. Sporn M.B. Yamamoto M. Kensler T.W. Eur. J. Pharmacol. 2009; 620: 138-144Crossref PubMed Scopus (215) Google Scholar).We showed that CDDO-Me action is mediated, at least in part, by AMPK activation. Although AMPK is ubiquitously expressed (38Hardie D.G. Carling D. Carlson M. Annu. Rev. Biochem. 1998; 67: 821-855Crossref PubMed Scopus (1265) Google Scholar), the in vivo effects of CDDO-Me have been primarily associated with increased glucose uptake in skeletal muscle, which involves AMPK activation (32Zhou G. Myers R. Li Y. Chen Y. Shen X. Fenyk-Melody J. Wu M. Ventre J. Doebber T. Fujii N. Musi N. Hirshman M.F. Goodyear L.J. Moller D.E. J. Clin. Invest. 2001; 108: 1167-1174Crossref PubMed Scopus (4332) Google Scholar, 39Fujii N. Aschenbach W.G. Musi N. Hirshman M.F. Goodyear L.J. Proc. Nutr. Soc. 2004; 63: 205-210Crossref PubMed Scopus (34) Google Scholar, 40Shaw R.J. Lamia K.A. Vasquez D. Koo S.H. Bardeesy N. Depinho R.A. Montminy M. Cantley L.C. Science. 2005; 310: 1642-1646Crossref PubMed Scopus (1537) Google Scholar). The increased phosphorylation and activation of AMPK by CDDO-Me would provide a mechanism for the observed improvements in glucose and lipid metabolism. Phosphorylation and inactivation of ACC by AMPK activation would inhibit the proximal and rate-limiting step of lipogenesis. These effects are likely to contribute to the capacity of CDDO-Me to lower triglycerides and FFA in vivo.AMPK activation is implicated as a mechanism for the induction of skeletal muscle glucose uptake; this effect is additive with insulin (41Hayashi T. Hirshman M.F. Kurth E.J. Winder W.W. Goodyear L.J. Diabetes. 1998; 47: 1369-1373Crossref PubMed Scopus (705) Google Scholar). Therefore, the observed association of increased glucose uptake and AMPK activation in isolated skeletal muscle suggests that the effect of CDDO-Me in augmenting muscle insulin action in vivo may be attributed to AMPK as well. AMPK mediates a decrease in SREBP-1 mRNA. FAS, a known lipogenic target gene for SREBP-1, is also down-regulated in CDDO-Me-treated hepatocytes, further contributing to the effect of CDDO-Me on modulating circulating lipids and reducing hepatic lipogenesis. It should be noted that increased SREBP-1 is postulated as a central mediator of insulin resistance in T2DM and related metabolic disorders (42Kakuma T. Lee Y. Higa M. Wang Z. Pan W. Shimomura I. Unger R.H. Proc. Natl. Acad. Sci. U.S.A. 2000; 97: 8536-8541Crossref PubMed Scopus (228) Google Scholar, 43Shimomura I. Matsuda M. Hammer R.E. Bashmakov Y. Brown M.S. Goldstein J.L. Mol. Cell. 2000; 6: 77-86Abstract Full Text Full Text PDF PubMed Scopus (686) Google Scholar) and that increased liver lipid content is implicated in hepatic insulin resistance (44McGarry J.D. Science. 1992; 258: 766-770Crossref PubMed Scopus (567) Google Scholar).The α subunit of AMPK contains the catalytic site, and phosphorylation of Thr-172 in its activation loop by one or more upstream kinases (AMPK kinase) is required for activation (28Wellen K.E. Hotamisligil G.S. J. Clin. Invest. 2005; 115: 1111-1119Crossref PubMed Scopus (3141) Google Scholar, 46Kemp B.E. Stapleton D. Campbell D.J. Chen Z.P. Murthy S. 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LKB1 is a tumor suppressor kinase and can phosphorylate the T-loop of all 12 known members of the human AMPK family (51Lizcano J.M. Göransson O. Toth R. Deak M. Morrice N.A. Boudeau J. Hawley S.A. Udd L. Mäkelä T.P. Hardie D.G. Alessi D.R. EMBO J. 2004; 23: 833-843Crossref PubMed Scopus (1042) Google Scholar). It is not clear whether LKB1 phosphorylation is required for AMPK activation and, if so, which site of phosphorylation is involved in AMPK activation. LKB1 is phosphorylated at Ser-325, Thr-366, and Ser-431 by upstream kinases. In addition, LKB1 autophosphorylates at Ser-31, Thr-185, Thr-189, Thr-336, and Ser-404 (52Alessi D.R. Sakamoto K. Bayascas J.R. Annu. Rev. Biochem. 2006; 75: 137-163Crossref PubMed Scopus (626) Google Scholar). Mutation of any of these phosphorylation sites to Ala (to abolish phosphorylation) or Glu (to mimic phosphorylation) does not significantly affect the in vitro catalytic activity of LKB1 or its intracellular localization (53Boudeau J. Baas A.F. Deak M. Morrice N.A. Kieloch A. Schutkowski M. Prescott A.R. Clevers H.C. Alessi D.R. EMBO J. 2003; 22: 5102-5114Crossref PubMed Scopus (351) Google Scholar, 54Sapkota G.P. Boudeau J. Deak M. Kieloch A. Morrice N. Alessi D.R. Biochem. J. 2002; 362: 481-490Crossref PubMed Scopus (79) Google Scholar, 55Sapkota G.P. Kieloch A. Lizcano J.M. Lain S. Arthur J.S. Williams M.R. Morrice N. Deak M. Alessi D.R. J. Biol. Chem. 2001; 276: 19469-19482Abstract Full Text Full Text PDF PubMed Scopus (211) Google Scholar). Recently, Zou and co-workers (56Xie Z. Dong Y. Scholz R. Neumann D. Zou M.H. Circulation. 2008; 117: 952-962Crossref PubMed Scopus (224) Google Scholar) demonstrated that phosphorylation of LKB1 Ser-428 is required for metformin-enhanced AMPK activation. However, the precise mechanism(s) underlying LKB1 activation, the relevant phosphorylation sites, and the upstream activating kinase(s) are still not well understood. Neither the activity of LKB1 itself nor that of AMPK-related kinases is influenced directly by agents known to activate AMPK, e.g. AICAR and metformin (57Davis B.J. Xie Z. Viollet B. Zou M.H. Diabetes. 2006; 55: 496-505Crossref PubMed Scopus (355) Google Scholar, 58Sakamoto K. Göransson O. Hardie D.G. Alessi D.R. Am. J. Physiol. Endocrinol. Metab. 2004; 287: E310-E317Crossref PubMed Scopus (262) Google Scholar, 59Sakamoto K. Murata T. Chuma H. Hori M. Ozaki H. Arterioscler. Thromb. Vasc. Biol. 2005; 25: 327-333Crossref PubMed Scopus (33) Google Scholar, 60Zou M.H. Hou X.Y. Shi C.M. Kirkpatick S. Liu F. Goldman M.H. Cohen R.A. J. Biol. Chem. 2003; 278: 34003-34010Abstract Full Text Full Text PDF PubMed Scopus (158) Google Scholar). Thus, how these agents lead to LKB1-dependent AMPK activation remains unclear to date. Our results suggest, however, that phosphorylation of LKB1 is necessary for CDDO-Me-mediated AMPK phosphorylation.It remains unclear how CDDO-Me activates LKB1. Our preliminary data suggest that it could work through activation of ERK1/2, a rate-limiting enzyme in MAPK pathway. A MAPK inhibitor that blocks ERK1/2 phosphorylation also inhibits AMPK phosphorylation, further supporting ERK1/2 as a possible upstream target for CDDO-Me. Much additional work will be needed to clearly define the underlying mechanisms involved.CDDO-Me is undergoing phase I trial for different cancers (61Dezube, B. J., Kurzrock, R., Eder, J. P., Supko, J. G., Meyer, C. J., Camacho, L. H., Andreeff, M., Konopleva, M., Lescale-Matys, L., Hong, D. (2007) Annual Meeting of the AACR-NCI-EORTC, International Conference on Molecular Targets and Cancer Therapeutics: Discovery, Biology, and Clinical Applications October 22–26, San Francisco, CA.Google Scholar). It is noteworthy that the dose of CDDO-Me used in the in vivo studies reported herein (2–3 mg/kg) is about 1 log lower than the doses required to achieve its anti-tumor effects (20–100 mg/kg) (45Ling X. Konopleva M. Zeng Z. Ruvolo V. Stephens L.C. Schober W. McQueen T. Dietrich M. Madden T.L. Andreeff M. Cancer Res. 2007; 67: 4210-4218Crossref PubMed Scopus (83) Google Scholar, 62Liby K. Yore M.M. Roebuck B.D. Baumgartner K.J. Honda T. Sundararajan C. Yoshizawa H. Gribble G.W. Williams C.R. Risingsong R. Royce D.B. Dinkova-Kostova A.T. Stephenson K.K. Egner P.A. Yates M.S. Groopman J.D. Kensler T.W. Sporn M.B. Cancer Res. 2008; 68: 6727-6733Crossref PubMed Scopus (48) Google Scholar). Therefore, it is likely that, clinically, the use of CDDO-Me as an anti-diabetic agent may require a substantially lower dose than that used in cancer therapy. To date, data from the ongoing phase I trials of CDDO-Me (RTA-402) indicate that toxicity of this agent even at the much higher anti-cancer dose is minimal. Therefore, it is possible that use of CDDO-Me for clinical management of T2DM could be achieved without serious side effects. IntroductionTriterpenoids, together with their close relatives, the steroids, are members of the cyclosqualenoid family (1Sporn M.B. Suh N. Carcinogenesis. 2000; 21: 525-530Crossref PubMed Scopus (439) Google Scholar). The semisynthetic triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO) 2The abbreviations used are: CDDO2-cyano-3,12-dioxooleana-1,9-dien-28-oic-acidCDDO-MeCDDO methyl esterAMPKAMP-activated protein kinaseACCacetyl-coA carboxylaseFFAfree fatty acidGTTglucose tolerance testITTinsulin tolerance testIRinsulin receptorAICAR5-amino-imidazole carboxamide ribosideWATwhite adipose tissueFASfatty acid synthaseSREBPsterol response element-binding proteinComp CCompound CPEPCKphosphoenolpyruvate carboxykinaseTGtriglycerideT2DMtype 2 diabetes mellitus. is structurally related to the pentacyclic triterpenoids oleanolic and ursolic acids. Studies with CDDO have revealed potent cellular differentiating, antiproliferative, proapoptotic (2Wang Y. Porter W.W. Suh N. Honda T. Gribble G.W. Leesnitzer L.M. Plunket K.D. Mangelsdorf D.J. Blanchard S.G. Willson T.M. Sporn M.B. Mol. Endocrinol. 2000; 14: 1550-1556Crossref PubMed Google Scholar), anti-inflammatory, and anticarcinogenic activities (3Huang M.T. Ho C.T. Wang Z.Y. Ferraro T. Lou Y.R. Stauber K. Ma W. Georgiadis C. Laskin J.D. Conney A.H. Cancer Res. 1994; 54: 701-708PubMed Google Scholar, 4Nishino H. Nishino A. Takayasu J. Hasegawa T. Iwashima A. Hirabayashi K. Iwata S. Shibata S. Cancer Res. 1988; 48: 5210-5215PubMed Google Scholar, 5Suh N. Honda T. Finlay H.J. Barchowsky A. Williams C. Benoit N.E. Xie Q.W. Nathan C. Gribble G.W. Sporn M.B. Cancer Res. 1998; 58: 717-723PubMed Google Scholar). This triterpenoid has been shown to induce monocytic differentiation of human myeloid leukemia cells, adipogenic differentiation of mouse 3T3-L1 fibroblasts, and nerve growth factor-induced neuronal differentiation of rat PC12 cells (6Suh N. Wang Y. Honda T. Gribble G.W. Dmitrovsky E. Hickey W.F. Maue R.A. Place A.E. Porter D.M. Spinella M.J. Williams C.R. Wu G. Dannenberg A.J. Flanders K.C. Letterio J.J. Mangelsdorf D.J. Nathan C.F. Nguyen L. Porter W.W. Ren R.F. Roberts A.B. Roche N.S. Subbaramaiah K. Sporn M.B. Cancer Res. 1999; 59: 336-341PubMed Google Scholar). CDDO enhanced the differentiation of acute promyelocytic leukemia cells in vitro and induced differentiation of all -trans retinoic acid-resistant acute promyelocytic leukemia cells (7Tabe Y. Konopleva M. Kondo Y. Contractor R. Tsao T. Konoplev S. Shi Y. Ling X. Watt J.C. Tsutsumi-Ishii Y. Ohsaka A. Nagaoka I. Issa J.P. Kogan S.C. Andreeff M. Cancer Biol. Ther. 2007; 6: 1967-1977Crossref PubMed Scopus (28) Google Scholar). The mechanism responsible for the differentiating action of CDDO was in part associated with activation of CEBP-β (8Koschmieder S. D'Alò F. Radomska H. Schöneich C. Chang J.S. Konopleva M. Kobayashi S. Levantini E. Suh N. Di Ruscio A. Voso M.T. Watt J.C. Santhanam R. Sargin B. Kantarjian H. Andreeff M. Sporn M.B. Perrotti D. Berdel W.E. Müller-Tidow C. Serve H. Tenen D.G. Blood. 2007; 110: 3695-3705Crossref PubMed Scopus (44) Google Scholar). Micromolar concentrations of CDDO have been observed to induce apoptosis in different cancer cell lines (9Gao X. Deeb D. Jiang H. Liu Y. Dulchavsky S.A. Gautam S.C. J. Neurooncol. 2007; 84: 147-157Crossref PubMed Scopus (85) Google Scholar, 10Hyer M.L. Shi R. Krajewska M. Meyer C. Lebedeva I.V. Fisher P.B. Reed J.C. Cancer Res. 2008; 68: 2927-2933Crossref PubMed Scopus (59) Google Scholar, 11Ikeda T. Nakata Y. Kimura F. Sato K. Anderson K. Motoyoshi K. Sporn M. Kufe D. Mol. Cancer Ther. 2004; 3: 39-45PubMed Google Scholar). CDDO inhibited the growth of several ovarian cancer cell lines that express peroxisome proliferator-activated receptor γ, but co-treatment with the peroxisome proliferator-activated receptor γ antagonist T007 did not block the apoptogenic effects of CDDO, suggesting a peroxisome proliferator-activated receptor γ-independent action (12Kodera Y. Takeyama K. Murayama A. Suzawa M. Masuhiro Y. Kato S. J. Biol. Chem. 2000; 275: 33201-33204Abstract Full Text Full Text PDF PubMed Scopus (182) Google Scholar, 13Melichar B. Konopleva M. Hu W. Melicharova K. Andreeff M. Freedman R.S. Gynecol. Oncol. 2004; 93: 149-154Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar).The C-28 methyl ester of CDDO, CDDO-Me, has been shown to decrease the viability of leukemic cell lines, including multidrug resistance 1-overexpressing cells (14Konopleva M. Tsao T. Ruvolo P. Stiouf I. Estrov Z. Leysath C.E. Zhao S. Harris D. Chang S. Jackson C.E. Munsell M. Suh N. Gribble G. Honda T. May W.S. 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