Compound Astragalus and Salvia miltiorrhiza extract inhibits cell proliferation, invasion and collagen synthesis in keloid fibroblasts by mediating transforming growth factor-β / Smad pathway

Authors

  • S. He,

    1. Department of Pharmacology and Institute of Natural Medicine, Anhui Medical University, Key Laboratoy of Antiinflammatory and Immunopharmacology, Ministry of Education, Hefei, Anhui 230032, China
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  • Y. Yang,

    1. Department of Pharmacology and Institute of Natural Medicine, Anhui Medical University, Key Laboratoy of Antiinflammatory and Immunopharmacology, Ministry of Education, Hefei, Anhui 230032, China
    2. Institute of Dermatology and Department of Dermatology, Anhui Medical University, Hefei, Anhui 230032, China
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  • X. Liu,

    1. Therapeutics Research Centre, University of Queensland, Princess Alexandra Hospital, Brisbane, Qld 4102, Australia
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  • W. Huang,

    1. Department of Pharmacology and Institute of Natural Medicine, Anhui Medical University, Key Laboratoy of Antiinflammatory and Immunopharmacology, Ministry of Education, Hefei, Anhui 230032, China
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  • X. Zhang,

    1. Department of Pharmaceutical Engineering, Hefei University of Technology, Hefei, Anhui 230009, China
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  • S. Yang,

    1. Institute of Dermatology and Department of Dermatology, Anhui Medical University, Hefei, Anhui 230032, China
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  • X. Zhang

    1. Institute of Dermatology and Department of Dermatology, Anhui Medical University, Hefei, Anhui 230032, China
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  • Funding sources
    This work was granted financial support from the National Natural Science Foundation of China (no. 81073098), the China Postdoctoral Science Foundation (no. 20060400716), and the Scientific Research Foundation for Talent of Anhui Province (no. 2008Z027).

  • Conflicts of interest
    None declared.

Yan Yang.
E-mail: yangyan276866@sohu.com

Summary

Background  The transforming growth factor (TGF)-β/Smad pathway plays a key role in keloid development. We have previously demonstrated that compound Astragalus and Salvia miltiorrhiza extract (CASE) inhibits liver fibrosis and reduces invasion capacity of HepG2 cells by mediating the TGF-β/Smad pathway. We therefore hypothesize that CASE may also exert antifibrotic effects in keloids by mediating the TGF-β/Smad pathway.

Objectives  To investigate the effects of CASE on cell proliferation, invasion and collagen synthesis in keloid fibroblasts, and to explore the effects of CASE on the TGF-β/Smad signal pathway in order to elucidate its mechanisms of action.

Methods  The inhibitory effects of CASE on keloid fibroblasts were evaluated. Cell proliferation was studied by MTT assay; cell invasion was observed utilizing Transwell invasion chambers; and collagen synthesis in keloid fibroblasts was measured by 3H-proline incorporation assay. Expression of proteins induced by TGF-β1 and their intracellular localization in keloid fibroblasts were investigated by Western blot and immunofluorescence, respectively. Plasminogen activator inhibitor-1 (PAI-1) transcriptional activity was measured by real-time reverse transcription–polymerase chain reaction.

Results  CASE significantly inhibited cell proliferation induced by newborn bovine serum as well as collagen synthesis and cell invasion induced by TGF-β1 in keloid fibroblasts, while it showed weak effects on normal fibroblasts. The phosphorylation of Smad2/3 was markedly reduced by CASE treatment, while CASE exhibited stronger inhibitory effects on linker region phosphorylation (pSmad2L and pSmad3L) compared with effects on C-terminal region phosphorylation (pSmad2C and pSmad3C). In addition, CASE blocked formation of Smad2/3/4 complexes and their nuclear translocation, but upregulated Smad7 expression in a dose-dependent manner. PAI-1 mRNA and protein levels were also suppressed by CASE treatment.

Conclusions  These results suggest that CASE exhibits inhibitory effects on cell proliferation, invasion and collagen synthesis in keloid fibroblasts, and its mechanisms of action may involve the TGF-β/Smad pathway.

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