1982, Bengbu Medical College, MD
1985, Sun Yat-Sen University, MS
1990, University of Heidelberg, Germany, PhD
Dr. Chen's Faculty Collaboration Database
Ras is the most established oncogene in human cancer, with its mutation (K-Ras) occurring in about 50% human colon cancer and its hyperexpression (H-Ras) in more than 50% of human breast cancer. Ras oncogene activity, however, is determined by downstream effectors and elucidation of this regulation is essential to understand why not all Ras mutations can lead to human malignancies. MAPKs (mitogen-activated protein kinases), including ERK, JNK, and p38, signal downstream of Ras by converting extracellular and Ras signals into specific cellular response through a group of transcription factors. Our previous work established that Ras-induced p38 alpha phosphorylation/activation inhibits the oncogene activity by negative feedback. Results from our recent studies further showed that p38 gamma, a p38 family protein, is induced by Ras and in turn required for Ras transformation in rat intestinal epithelial cells and for Ras-invasive activity in human breast cancer. These results together indicate that signaling integrations among p38 family members determine Ras oncogene activity in a given tissues and p38 proteins regulate Ras activity by isoform-dependent mechanisms. Currently, we are investigating mechanisms by which Ras induces p38 gamma expression and by which p38gamma is required for Ras-induced transformation / invasion.
Nuclear receptors are group of transcription factors that play an important role in reproduction, homeostasis, and cancer development through regulating gene expression in response to their ligand. Our second research interest is to study signal cross-talks between Ras/MAPK pathways and nuclear receptors. Studies from our lab have established a c-Jun/AP-1 dependent trans-activation for stress-induced vitamin D receptor (VDR) expression and an anti-apoptotic activity of VDR by a K-ras-dependent mechanism. Our results further showed that another nuclear receptor ER (estrogen receptor) inhibits stress MAPK-mediated cell death independent of its transcriptional activity by converting pro-apoptotic c-Jun activity into a c-Jun-dependent AP1 transcription. These results together suggest that nuclear receptors may cooperate with Ras/MAPKs to regulate stress-response independent of their transcription activity. We are currently investigating whether regulation of nuclear receptors represents a novel strategy for human cancer treatment.
(Ma S, Yin N, Qi X, Pfister SL, Zhang MJ, Ma R, Chen G.) Oncotarget. 2015 May 30;6(15):13320-33.
(Qi X, Yin N, Ma S, Lepp A, Tang J, Jing W, Johnson B, Dwinell MB, Chitambar CR, Chen G.) Stem Cells. 2015 Sep;33(9):2738-47.
(Yin N, Qi X, Tsai S, Lu Y, Basir Z, Oshima K, Thomas JP, Myers CR, Stoner G, Chen G.) Oncogene. 2016 Feb 25;35(8):1039-48.
(Qi X, Xie C, Hou S, Li G, Yin N, Dong L, Lepp A, Chesnik MA, Mirza SP, Szabo A, Tsai S, Basir Z, Wu S, Chen G.) Oncotarget. 2014 Jun 30;5(12):4269-82.
(Suresh PS, Ma S, Migliaccio A, Chen G.) Mol Cancer Ther. 2014 Jan;13(1):230-8.
(Kobayashi Y, Qi X, Chen G.) Genes Cancer. 2012 Jul;3(7-8):521-30.
(Hou S, Suresh PS, Qi X, Lepp A, Mirza SP, Chen G.) J Biol Chem. 2012 Aug 10;287(33):27895-905.
p38γ mitogen-activated protein kinase (MAPK) confers breast cancer hormone sensitivity by switching estrogen receptor (ER) signaling from classical to nonclassical pathway via stimulating ER phosphorylation and c-Jun transcription.
(Qi X, Zhi H, Lepp A, Wang P, Huang J, Basir Z, Chitambar CR, Myers CR, Chen G.) J Biol Chem. 2012 Apr 27;287(18):14681-91.
(Qi X, Hou S, Lepp A, Li R, Basir Z, Lou Z, Chen G.) J Biol Chem. 2011 Oct 14;286(41):35883-90.
(Zhi HY, Hou SW, Li RS, Basir Z, Xiang Q, Szabo A, Chen G.) Oncogene. 2011 Apr 07;30(14):1706-15.
(Hou SW, Zhi HY, Pohl N, Loesch M, Qi XM, Li RS, Basir Z, Chen G.) Cancer Res. 2010 Apr 01;70(7):2901-10.
(Loesch M, Zhi HY, Hou SW, Qi XM, Li RS, Basir Z, Iftner T, Cuenda A, Chen G.) J Biol Chem. 2010 May 14;285(20):15149-58.