Proteasome inhibitor inhibits proliferation and induces apoptosis in renal interstitial fibroblasts.

Abstract

BACKGROUND:

The ubiquitin proteasome pathway plays a pivotal role in controlling cell proliferation, apoptosis and differentiation in a variety of normal and tumor cells. This study aimed to investigate the role of a proteasome inhibitor on proliferation, apoptosis and related proteins in renal interstitial fibroblasts (NRK-49F).

METHODS:

NRK-49F cells were induced using transforming growth factor-β1 (TGF-β1) and pretreated with the proteasome inhibitor MG-132. Cell proliferation was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The cell cycle and apoptosis were analyzed using flow cytometry. Apoptosis was also analyzed using a DNA ladder. The protein expression of p53, p27, p21, caspase-3, Bcl-2 and Bax was examined using western blots.

RESULTS:

The results showed that TGF-β1 (5 ng/ml) can stimulate the proliferation of NRK-49F cells.MG-132 (0.25-5 μM) inhibited TGF-β1-induced proliferation in a dose-dependent manner through G1-arrest; TGF-β1 alone did not induce apoptosis (3.8 ± 0.4% vs. 4.7 ± 1.6%). However, pretreatment with MG-132 significantly induced apoptosis in TGF-b1-stimulated NRK-49F cells in a dose-dependent manner. A typical DNA ladder was also confirmed in these two groups. Western blot analysis showed that MG-132 activated p53, p21, caspase-3 and Bax, and inhibited Bcl-2 in a dose-dependent manner, while p27 expression remained unchanged.

CONCLUSIONS:

A proteasome inhibitor inhibited proliferation and induced apoptosis in renal interstitial fibroblasts stimulated by TGF-β1. The mechanism may relate to the p53, p21, caspase-3, Bcl-2 and Bax pathways. Our results suggest that a proteasome inhibitor could be a new strategy to treat renal interstitial fibrosis.

• Authors: Bingbing Zhu, Yuanmeng Jin, Lin Han, Hui Chen, Fang Zhong, Weiming Wang, Nan Chen
• Journal: Pharmacological reports : PR (Pharmacol Rep) Vol. 65 Issue 5 Pg. 1357-65 ( 2013) ISSN: 2299-5684 [Electronic] Switzerland
• PMID: 24399732 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Bax protein, rat
• Cdkn1a protein, rat
• Cdkn1b protein, rat
• Cyclin-Dependent Kinase Inhibitor p21
• Leupeptins
• Proteasome Inhibitors
• Proto-Oncogene Proteins c-bcl-2
• Transforming Growth Factor beta1
• Tumor Suppressor Protein p53
• bcl-2-Associated X Protein
• Cyclin-Dependent Kinase Inhibitor p27
• Casp3 protein, rat
• Caspase 3
• Proteasome Endopeptidase Complex
• benzyloxycarbonylleucyl-leucyl-leucine aldehyde

Topics

• Animals
• Apoptosis (drug effects)
• Caspase 3 (metabolism)
• Cell Line
• Cell Proliferation (drug effects)
• Cyclin-Dependent Kinase Inhibitor p21 (metabolism)
• Cyclin-Dependent Kinase Inhibitor p27 (metabolism)
• Dose-Response Relationship, Drug
• Fibroblasts (drug effects, enzymology, pathology)
• Fibrosis
• Kidney (drug effects, enzymology, pathology)
• Leupeptins (pharmacology)
• Proteasome Endopeptidase Complex (metabolism)
• Proteasome Inhibitors (pharmacology)
• Proto-Oncogene Proteins c-bcl-2 (metabolism)
• Rats
• Transforming Growth Factor beta1 (pharmacology)
• Tumor Suppressor Protein p53 (metabolism)
• bcl-2-Associated X Protein (metabolism)