In situ normoxia enhances survival and proliferation rate of human adipose tissue-derived stromal cells without increasing the risk of tumourigenesis

PLoS One. 2015 Jan 23;10(1):e0115034. doi: 10.1371/journal.pone.0115034. eCollection 2015.

Abstract

Adipose tissue-derived stromal cells (ASCs) natively reside in a relatively low-oxygen tension (i.e., hypoxic) microenvironment in human body. Low oxygen tension (i.e., in situ normoxia), has been known to enhance the growth and survival rate of ASCs, which, however, may lead to the risk of tumourigenesis. Here, we investigated the tumourigenic potential of ASCs under their physiological condition to ensure their safe use in regenerative therapy. Human ASCs isolated from subcutaneous fat were cultured in atmospheric O2 concentration (21% O2) or in situ normoxia (2% O2). We found that ASCs retained their surface markers, tri-lineage differentiation potential, and self-renewal properties under in situ normoxia without altering their morphology. In situ normoxia displayed a higher proliferation and viability of ASCs with less DNA damage as compared to atmospheric O2 concentration. Moreover, low oxygen tension significantly up-regulated VEGF and bFGF mRNA expression and protein secretion while reducing the expression level of tumour suppressor genes p16, p21, p53, and pRb. However, there were no significant differences in ASCs telomere length and their relative telomerase activity when cultured at different oxygen concentrations. Collectively, even with high proliferation and survival rate, ASCs have a low tendency of developing tumour under in situ normoxia. These results suggest 2% O2 as an ideal culture condition for expanding ASCs efficiently while maintaining their characteristics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / cytology
  • Adult
  • Carcinogenesis*
  • Cell Hypoxia
  • Cell Proliferation*
  • Cells, Cultured
  • Female
  • Humans
  • Mesenchymal Stem Cells / cytology
  • Mesenchymal Stem Cells / metabolism*
  • Mesenchymal Stem Cells / physiology
  • Oxygen / metabolism*
  • Telomerase / metabolism
  • Telomere Homeostasis
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism

Substances

  • Tumor Suppressor Proteins
  • Vascular Endothelial Growth Factor A
  • Telomerase
  • Oxygen

Grant support

This work was financially supported by the University of Malaya, High Impact Research Grant (UM.C/HIR/MOHE/ENG/44) from the Ministry of Higher Education Malaysia. FX was partially supported by the Major International Joint Research Program of China (11120101002), the National Natural Science Foundation of China (11372243), and the National 111 Project of China (B06024). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.