Mithramycin reduces expression of fibro-proliferative mRNAs in human gingival fibroblasts

Abstract

Fibrosis is characterized by loss of normal structure and function of a tissue or organ resulting from excessive fibroblast proliferation and extracellular matrix production. Currently, there is no efficient treatment for fibrosis. Herein, we test effects of the drug mithramycin, which targets the Sp1 family of transcription factors, on mRNA expression by human gingival fibroblasts. Mithramycin reduced expression of connective tissue growth factor and type I collagen mRNAs. Microarray profiling revealed that mithramycin selectively blocked expression of cell proliferation and transforming growth factor-beta (TGF-β) signalling clusters. These microarray data were validated using real-time polymerase chain reaction and western blot analyses. Mithramycin suppressed expression of key profibrotic TGF-β signalling mediators, Smad3 and p300, as well as cell proliferation. Taken together, these data suggest that the Sp1 family of transcription factors may contribute to expression of fibrogenic genes in human gingival fibroblasts; drugs targeting the Sp1 family may be beneficial in treatment of fibro-proliferative diseases.

A Novel Mithramycin Analogue with High Antitumor Activity and Less Toxicity Generated by Combinatorial Biosynthesis

“…9–11 For example, it has been shown that 1 selectively blocks expression of cell proliferation and transforming growth factor-beta (TGF-β) signalling clusters in human gingival fibroblasts, and in glioma cells it was found to suppress and delay tumor cell migration; 12,13 also, 1 supresses the growth of Ewing sarcoma family of tumors (ESFTs) xenografts-bearing mice. In this context, 1 was identified in a screening of 50,000 compounds as the lead compound for the inhibition of aggressive ESFTs, for its in vitro and in vivo inhibition of the Ewing sarcoma breakpoint region 1 and Friend leukemia virus integration 1 (EWS-FLI1) TF, a protein that had previously been thought to be undruggable.…”

Loss of PPARγ expression by fibroblasts enhances dermal wound closure

“…Real-time PCR to detect the expression of target genes was performed essentially as previously described [ 20 , 21 ]. Cells were cultured until 50% confluence and treated for 24 hours with dimethyl sulfoxide (DMSO) or troglitazone (40 μM, EMD Biosciences, Billerica, MA, USA) and total RNA was isolated (RNeasy; QIAGEN, Toronto, ON, Canada).…”

The hard problem: Mechanotransduction perpetuates the myofibroblast phenotype in scleroderma fibrosis

“…Sp1 is responsive to sheer stress and integrin/FAK activation. [72][73][74][75][76] Sp1 DNA binding activity is elevated in SSc fibroblasts and the selective Sp1 inhibitor reduces the overexpression of CCN2 in SSc fibroblasts and selectively impairs expression of pro-fibrotic mRNAs in fibroblasts [77][78][79][80] (Figure 1).…”