Identification of novel target genes specifically activated by deregulated E2F in human normal fibroblasts
GENES TO CELLS
Authors: Kitamura, Hodaka; Ozono, Eiko; Iwanaga, Ritsuko; Bradford, Andrew P.; Okuno, Junko; Shimizu, Emi; Kurayoshi, Kenta; Kugawa, Kazuyuki; Toh, Hiroyuki; Ohtani, Kiyoshi
Abstract
The transcription factor E2F is the principal target of the tumor suppressor pRB. E2F plays crucial roles not only in cell proliferation by activating growth-related genes but also in tumor suppression by activating pro-apoptotic and growth-suppressive genes. We previously reported that, in human normal fibroblasts, the tumor suppressor genes ARF, p27(Kip1) and TAp73 are activated by deregulated E2F activity induced by forced inactivation of pRB, but not by physiological E2F activity induced by growth stimulation. In contrast, growth-related E2F targets are activated by both E2F activities, underscoring the roles of deregulated E2F in tumor suppression in the context of dysfunctional pRB. In this study, to further understand the roles of deregulated E2F, we explored new targets that are specifically activated by deregulated E2F using DNA microarray. The analysis identified nine novel targets (BIM, RASSF1, PPP1R13B, JMY, MOAP1, RBM38, ABTB1, RBBP4 and RBBP7), many of which are involved in the p53 and RB tumor suppressor pathways. Among these genes, the BIM gene was shown to be activated via atypical E2F-responsive promoter elements and to contribute to E2F1-mediated apoptosis. Our results underscore crucial roles of deregulated E2F in growth suppression to counteract loss of pRB function.
Analysis of pigmented villonodular synovitis with genome-wide complementary DNA microarray and tissue array technology reveals insight into potential novel therapeutic approaches
ARTHRITIS AND RHEUMATISM
Authors: Finis, K; Sultmann, H; Ruschhaupt, M; Buness, A; Helmchen, B; Kuner, R; Gross, ML; Fink, B; Schirmacher, P; Poustka, A; Berger, I
Abstract
Objective. To characterize the gene expression profile and determine potential diagnostic markers and therapeutic targets in pigmented villonodular synovitis (PVNS). Methods. Gene expression patterns in 11 patients with PVNS, 18 patients with rheumatoid arthritis (RA), and 19 patients with osteoarthritis (OA) were investigated using genome-wide complementary DNA microarrays. Validation of differentially expressed genes was performed by real-time quantitative polymerase chain reaction and immunohistochemical analysis on tissue arrays (80 patients with PVNS, 51 patients with RA, and 20 patients with OA). Results. The gene expression profile in PVNS was clearly distinct from those in RA and OA. One hundred forty-one up-regulated genes and 47 down-regulated genes were found in PVNS compared with RA, and 153 up-regulated genes and 89 down-regulated genes were found in PVNS compared with OA (fold change >= 1.5; Q <= 0.001). Genes differentially expressed in PVNS were involved in apoptosis regulation, matrix degradation, and inflammation (ALOX5AP, ATP6V1B2, CD53, CHBL1, CTSL, CXCR4, HSPA8, HSPCA, LAPTM5, MHP9, MOAP1, and SPP1). Conclusion. The gene expression signature in PVNS is similar to that of activated macrophages and is consistent with the local destructive course of the disease. The gene and protein expression patterns suggest that the ongoing proliferation in PVNS is sustained by apoptosis resistance. This result suggests the possibility of a potential novel therapeutic intervention against PVNS.