Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
 10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tristetraprolin (TTP or ZFP36) is a tandem CCCH zinc-finger RNA-binding protein that regulates the stability of certain AU-rich element (ARE) mRNAs. Recent work suggests that TTP is deficient in cancer cells when compared with normal cell types. In this study we found that TTP expression was lower in invasive breast cancer cells (MDAMB231) compared with normal breast cell lines MCF12A and MCF-10. TTP targets were probed using a novel approach by expressing the C124R zinc-finger TTP mutant that functions as dominant negative and increases target mRNA expression. In contrast to wild-type TTP, C124R TTP was able to increase certain ARE-mRNA expressions in serum-stimulated breast cancer cells. Using an ARE-gene microarray, novel targets of TTP regulation were identified, namely, urokinase plasminogen activator (uPA), uPA receptor and matrix metalloproteinase-1, all known to have prominent roles in breast cancer invasion and metastasis. Expression of these targets was upregulated in tumorigenic types, particularly in highly invasive MDAMB231. The mRNA half-lives of these TTP-regulated genes were increased in TTP-knockout embryonic mouse fibroblasts, as assessed using real-time polymerase chain reaction, whereas forced restoration of TTP by transfection led to a reduction in their mRNA levels. RNA immunoprecipitation confirmed an association of TTP, but not C124R, with these target transcripts. Moreover, TTP reduced, whereas the mutant C124R TTP increased, the activity of reporter constructs fused to target ARE. As a result of TTP regulation, invasiveness of MDAMB231 cells was reduced. The data suggest that TTP, in a 3' untranslated region-and ARE-dependent manner, regulates an important subset of cancer-related genes that are involved in cellular growth, invasion and metastasis.
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PMID:The RNA-binding zinc-finger protein tristetraprolin regulates AU-rich mRNAs involved in breast cancer-related processes. 2049 46

The activities of RNA-binding proteins are perturbed in several pathological conditions, including cancer. These proteins include tristetraprolin (TTP, ZFP36) and HuR (ELAVL1), which respectively promote the decay or stability of adenylate-uridylate-rich (AU-rich) mRNAs. Here, we demonstrated that increased stabilization and subsequent over-expression of HuR mRNA were coupled to TTP deficiency. These findings were observed in breast cancer cell lines with an invasive phenotype and were further confirmed in ZFP36-knockout mouse fibroblasts. We show that TTP-HuR imbalance correlated with increased expression of AU-rich element (ARE) mRNAs that code for cancer invasion genes. The microRNA miR-29a was abundant in invasive breast cancer cells when compared to non-tumourigenic cell types. When normal breast cells were treated with miR-29a, HuR mRNA and protein expression were up-regulated. MiR-29a recognized a seed target in the TTP 3' UTR and a cell-permeable miR-29a inhibitor increased TTP activity towards HuR 3' UTR. This led to HuR mRNA destabilization and restoration of the aberrant TTP-HuR axis. Subsequently, the cancer invasion factors uPA, MMP-1 and MMP-13, and cell invasiveness, were decreased. The TTP:HuR mRNA ratios were also perturbed in samples from invasive breast cancer patients when compared with normal tissues, and were associated with invasion gene expression. This study demonstrates that an aberrant ARE-mediated pathway in invasive cancer can be normalized by targeting the aberrant and functionally coupled TTP-HuR axis, indicating a potential therapeutic approach.
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PMID:miR-29a inhibition normalizes HuR over-expression and aberrant AU-rich mRNA stability in invasive cancer. 2338 14