Flowchart: Preparation: MEN1
 


                 

       

Text Box: P18


                                            

                                                 

                                                                                     

 

Text Box: Men1Lung cancer

Neuroendocrine disease

                                          

                            

                                                   

Text Box: H3K4 Text Box: Estrogen Text Box: Vitamin D
 


                                                     

 2007/11/3/32                 

Mol Cell Biol. 2007 Feb;27(4):1495-504. Epub 2006 Dec 4.Click here to read Click here to readLinks

p18Ink4c, but not p27Kip1, collaborates with Men1 to suppress neuroendocrine organ tumors.

Bai F, Pei XH, Nishikawa T, Smith MD, Xiong Y.

Lineberger Comprehensive Cancer Center, Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7295, USA.

Mutant mice lacking both cyclin-dependent kinase (CDK) inhibitors p18(Ink4c) and p27(Kip1) develop a tumor spectrum reminiscent of human multiple endocrine neoplasia (MEN) syndromes. To determine how p18 and p27 genetically interact with Men1, the tumor suppressor gene mutated in familial MEN1, we characterized p18-Men1 and p27-Men1 double mutant mice. Compared with their corresponding single mutant littermates, the p18(-/-); Men1(+/-) mice develop tumors at an accelerated rate and with an increased incidence in the pituitary, thyroid, parathyroid, and pancreas. In the pituitary and pancreatic islets, phosphorylation of the retinoblastoma (Rb) protein at both CDK2 and CDK4/6 sites was increased in p18(-/-) and Men1(+/-) cells and was further increased in p18(-/-); Men1(+/-) cells. The remaining wild-type Men1 allele was lost in most tumors from Men1(+/-) mice but was retained in most tumors from p18(-/-); Men1(+/-) mice. Combined mutations of p27(-/-) and Men1(+/-), in contrast, did not exhibit noticeable synergistic stimulation of Rb kinase activity, cell proliferation, and tumor growth. These results demonstrate that functional collaboration exists between p18 and Men1 and suggest that Men1 may regulate additional factor(s) that interact with p18 and p27 differently.

PMID: 17145768 [PubMed - indexed for MEDLINE]

Cancer Res. 2006 May 1;66(9):4929-35.Click here to read Links

Menin links estrogen receptor activation to histone H3K4 trimethylation.

Dreijerink KM, Mulder KW, Winkler GS, Höppener JW, Lips CJ, Timmers HT.

Departments of Physiological Chemistry, University Medical Center Utrecht, Utrecht, the Netherlands.

The product of the multiple endocrine neoplasia type 1 (MEN1) tumor suppressor gene, menin, is an integral component of MLL1/MLL2 histone methyltransferase complexes specific for Lys4 of histone H3 (H3K4). We show that menin is a transcriptional coactivator of the nuclear receptors for estrogen and vitamin D. Activation of the endogenous estrogen-responsive TFF1 (pS2) gene results in promoter recruitment of menin and in elevated trimethylation of H3K4. Knockdown of menin reduces both activated TFF1 (pS2) transcription and H3K4 trimethylation. In addition, menin can directly interact with the estrogen receptor-alpha (ERalpha) in a hormone-dependent manner. The majority of disease-related MEN1 mutations prevent menin-ERalpha interaction. Importantly, ERalpha-interacting mutants are also defective in coactivator function. Our results indicate that menin is a critical link between recruitment of histone methyltransferase complexes and nuclear receptor-mediated transcription.

PMID: 16651450 [PubMed - indexed for MEDLINE]

The tumor suppressor menin regulates hematopoiesis and myeloid transformation by influencing Hox gene expression.

Chen YX, Yan J, Keeshan K, Tubbs AT, Wang H, Silva A, Brown EJ, Hess JL, Pear WS, Hua X.

Abramson Family Cancer Research Institute, Department of Cancer Biology, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA 19104-6160, USA.

Menin is the product of the tumor suppressor gene Men1 that is mutated in the inherited tumor syndrome multiple endocrine neoplasia type 1 (MEN1). Menin has been shown to interact with SET-1 domain-containing histone 3 lysine 4 (H3K4) methyltransferases including mixed lineage leukemia proteins to regulate homeobox (Hox) gene expression in vitro. Using conditional Men1 knockout mice, we have investigated the requirement for menin in hematopoiesis and myeloid transformation. Men1 excision causes reduction of Hoxa9 expression, colony formation by hematopoietic progenitors, and the peripheral white blood cell count. Menin directly activates Hoxa9 expression, at least in part, by binding to the Hoxa9 locus, facilitating methylation of H3K4, and recruiting the methylated H3K4 binding protein chd1 to the locus. Consistent with signaling downstream of menin, ectopic expression of both Hoxa9 and Meis1 rescues colony formation defects in Men1-excised bone marrow. Moreover, Men1 excision also suppresses proliferation of leukemogenic mixed lineage leukemia-AF9 fusion-protein-transformed myeloid cells and Hoxa9 expression. These studies uncover an important role for menin in both normal hematopoiesis and myeloid transformation and provide a mechanistic understanding of menin's function in these processes that may be used for therapy.

PMID: 16415155 [PubMed - indexed for MEDLINE]