In vitro: |
Tumour Biol. 2014 Dec;35(12):11903-11. | Nobiletin suppresses the proliferation and induces apoptosis involving MAPKs and caspase-8/-9/-3 signals in human acute myeloid leukemia cells.[Pubmed: 25164609] | Nobiletin, a compound isolated from citrus fruits, is a polymethoxylated flavone derivative that was shown to have anti-inflammatory and anticancer activities in various solid tumors. The anticancer effect of nobiletin on nonsolid tumor remains unclear.
METHODS AND RESULTS:
Herein, the molecular mechanisms by which nobiletin exerts its anticancer effects on acute myeloid leukemia (AML) cells were investigated. The results showed that nobiletin suppressed cell proliferation in various types of AML cell lines. Moreover, nobiletin induced cell-cycle arrest of HL-60 AML cells at the G0/G1 phase by suppressing extracellular signal-regulated kinase (ERK) activity. Furthermore, nobiletin effectively induced apoptosis of HL-60 cells through caspase-8, caspase-9, and caspases-3 activation concomitantly with a marked induction of p38 mitogen-activated protein kinase (MAPK) activation, but without affecting expression levels of Bcl-2, Bax, or Bid.
CONCLUSIONS:
Taken together, our results suggest that nobiletin inhibited HL-60 cell proliferation through inducing cell-cycle arrest and apoptosis and could serve as a potential additional chemotherapeutic agent for treating AML. | Expert Opin Ther Targets. 2015 Mar;19(3):307-20. | Nobiletin inhibits invasion and migration of human nasopharyngeal carcinoma cell lines by involving ERK1/2 and transcriptional inhibition of MMP-2.[Pubmed: 25563790] | Nasopharyngeal carcinoma (NPC) is known for its high incidence of neck lymph node metastasis, which represents poor prognosis. Nobiletin is a citrus polymethoxyflavonoid that suppresses tumor growth and metastasis, both of which depend on angiogenesis in previous studies. However, the effect of Nobiletin on human NPC cells metastasis has not been clearly clarified.
METHODS AND RESULTS:
In this study, we determine the effects of Nobiletin on the migration and invasion in NPC cells.
Nobiletin significantly inhibited migration/invasion capacities of HONE-1 and NPC-BM cell lines. The results of gelatin zymography and western blotting revealed that the activities and protein levels of the MMP-2 were inhibited by Nobiletin. Nobiletin also showed that inhibits phosphorylation of ERK1/2. Tests of the real-time PCR and promoter assays evaluated the inhibitory effects of Nobiletin on MMP-2 expression in human NPC cells. Nobiletin inhibits MMP-2 expression, up-regulating tissue inhibitor of metalloproteinase-2 and down-regulation of the transcription factors of NF-κB and activator protein 1 (AP-1) signaling pathways. Finally, an administration of Nobiletin effectively suppressed the tumor formation and metastasis in the NPC xenograft model in vivo.
CONCLUSIONS:
Nobiletin may have potential use as a chemo-preventive agent against nasopharyngeal cancer metastasis. | Biochem Pharmacol. 2003 Jun 15;65(12):2065-71. | Novel anti-inflammatory actions of nobiletin, a citrus polymethoxy flavonoid, on human synovial fibroblasts and mouse macrophages.[Pubmed: 12787887] | We previously reported that nobiletin (5,6,7,8,3',4'-hexamethoxy flavone), a citrus polymethoxy flavonoid, effectively interferes with the production of promatrix metalloproteinase (proMMP)-9/progelatinase B in rabbit synovial fibroblasts [J. Rheumatol. 27 (2000) 20].
METHODS AND RESULTS:
In this paper, we further examine the effects of nobiletin on the production of cyclooxygenases (COXs), prostaglandin (PG) E(2), and proinflammatory cytokines in human synovial fibroblasts and the mouse macrophage J774A.1 cell line. Nobiletin suppressed the interleukin (IL)-1-induced production of PGE(2) in human synovial cells in a dose-dependent manner (<64 microM). Additionally, it selectively downregulated COX-2, but not COX-1 mRNA expression. Nobiletin also interfered with the lipopolysaccharide-induced production of PGE(2) and the gene expression of proinflammatory cytokines including IL-1alpha, IL-1beta, TNF-alpha and IL-6 in mouse J774A.1 macrophages. In addition, nobiletin downregulated the IL-1-induced gene expression and production of proMMP-1/procollagenase-1 and proMMP-3/prostromelysin-1 in human synovial fibroblasts.
CONCLUSIONS:
In contrast, production of the endogenous MMP inhibitor, TIMP-1, was augmented by nobiletin. These anti-inflammatory actions of nobiletin are very similar to those of anti-inflammatory steroids such as dexamethasone, and the upregulation of TIMP-1 production is a unique action of nobiletin. Therefore, these results further support the notion that nobiletin is likely to be a candidate for characterization as a novel immunomodulatory and anti-inflammatory drug. | Oncotarget . 2016 Jun 7;7(23):35208-23. | Nobiletin inhibits human osteosarcoma cells metastasis by blocking ERK and JNK-mediated MMPs expression[Pubmed: 27144433] | Nobiletin, a polymethoxyflavone, has a few pharmacological activities, including anti-inflammation and anti-cancer effects. However, its effect on human osteosarcoma progression remains uninvestigated. Therefore, we examined the effectiveness of nobiletin against cellular metastasis of human osteosarcoma and the underlying mechanisms. Nobiletin, up to 100 μM without cytotoxicity, significantly decreased motility, migration and invasion as well as enzymatic activities, protein levels and mRNA expressions of matrix metalloproteinase (MMP)-2 and MMP-9 in U2OS and HOS cells. In addition to inhibition of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), the inhibitory effect of nobiletin on the DNA-binding activity of the transcription factor nuclear factor-kappa B (NF-κB), cAMP response element-binding protein (CREB), and specificity protein 1 (SP-1) in U2OS and HOS cells. Co-treatment with ERK and JNK inhibitors and nobiletin further reduced U2OS cells migration and invasion. These results indicated that nobiletin inhibits human osteosarcoma U2OS and HOS cells motility, migration and invasion by down-regulating MMP-2 and MMP-9 expressions via ERK and JNK pathways and through the inactivation of downstream NF-κB, CREB, and SP-1. Nobiletin has the potential to serve as an anti-metastatic agent for treating osteosarcoma. |
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In vivo: |
Mol Nutr Food Res. 2015 May;59(5):829-42. | Citrus nobiletin ameliorates experimental colitis by reducing inflammation and restoring impaired intestinal barrier function.[Pubmed: 25655748] | Inflammatory bowel disease is a chronic inflammatory disorder of the gastrointestinal tract. Citrus nobiletin can exert robust anti-inflammatory effects in vivo and in vitro. We evaluated the impact of nobiletin on the excessive inflammatory response and impaired barrier function in a rodent colitis model.
METHODS AND RESULTS:
Colitis was established by infusion with 1 mL 2,4,6-trinitrobenzene sulfonic acid (TNBS) dissolved in ethanol (40% v/v) in rats at a 125 mg/kg dose. Caco-2 cell monolayer exposed to LPSs is used as a culture model for intestinal permeability measurements. Nobiletin decreased rat epithelial proinflammatory cytokines and mediators production. Nobiletin restored impaired barrier function in colitic rats and Caco-2 monolayer. Nobiletin decreased protein expressions of Akt, nuclear factor-kappa B (NF-κB), and myosin light chain kinase (MLCK) isolated from rat intestinal epithelial tissue and Caco-2 cell, respectively. PI3K inhibitor or siRNA targeting of either Akt or NF-κB mitigated the impact of nobiletin on MLCK expression and barrier function in Caco-2 monolayer, respectively.
CONCLUSIONS:
Nobiletin exerted anti-inflammatory effects in TNBS-induced colitis through the downregulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) expression. Nobiletin restored barrier function, which had been damaged after TNBS administration, through the inhibition of the Akt-NF-κB-MLCK pathway.
| Nat Commun . 2019 Aug 28;10(1):3923. | Nobiletin fortifies mitochondrial respiration in skeletal muscle to promote healthy aging against metabolic challenge[Pubmed: 31462679] | Circadian disruption aggravates age-related decline and mortality. However, it remains unclear whether circadian enhancement can retard aging in mammals. We previously reported that the small molecule Nobiletin (NOB) activates ROR (retinoid acid receptor-related orphan receptor) nuclear receptors to potentiate circadian oscillation and protect against metabolic dysfunctions. Here we show that NOB significantly improves metabolic fitness in naturally aged mice fed with a regular diet (RD). Furthermore, NOB enhances healthy aging in mice fed with a high-fat diet (HF). In HF skeletal muscle, the NOB-ROR axis broadly activates genes for mitochondrial respiratory chain complexes (MRCs) and fortifies MRC activity and architecture, including Complex II activation and supercomplex formation. These mechanisms coordinately lead to a dichotomous mitochondrial optimization, namely increased ATP production and reduced ROS levels. Together, our study illustrates a focal mechanism by a clock-targeting pharmacological agent to optimize skeletal muscle mitochondrial respiration and promote healthy aging in metabolically stressed mammals. |
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