Clinical & Experimental Metastasis

, Volume 24, Issue 2, pp 107–119 | Cite as

Parathyroid hormone-related protein and ezrin are up-regulated in human lung cancer bone metastases

  • Xiyun Deng
  • Sarah H. Tannehill-Gregg
  • Murali V. P. Nadella
  • Guangchun He
  • Andrea Levine
  • Ya Cao
  • Thomas J. RosolEmail author
Research Paper


Lung cancer often metastasizes to bone in patients with advanced disease. Identification of the factors involved in the interactions between lung cancer cells and bone will improve the prevention and treatment of bone metastases. We identified changes in metastasis-related gene expression of human HARA lung squamous carcinoma cells co-cultured with neonatal mouse calvariae using a pathway-specific microarray analysis. Nine genes were up-regulated and two genes down-regulated in HARA cells co-cultured with mouse calvariae. Five of the nine up-regulated genes, including caveolin 1, CD44, EphB2, ezrin, and Parathyroid hormone-related protein (PTHrP), and one down-regulated gene, SLPI, were further confirmed by Reverse transcription-polymerase chain reaction (RT-PCR). A mouse model was subsequently used to study the role of PTHrP and ezrin in bone metastasis in vivo. PTHrP (all three isoforms) and ezrin were up-regulated in HARA cells at sites of bone metastasis as detected by RT-PCR and immunohistochemistry. The PTHrP 141 mRNA isoform was increased by the greatest extent (13.9-fold) in bone metastases compared to PTHrP 139 and PTHrP 173 mRNA. We then generated a HARA cell line in which PTHrP expression was inducibly silenced by RNA interference. Silencing of PTHrP expression caused significant reduction of submembranous F-actin and decreased HARA cell invasion. Ezrin up-regulation was confirmed by Western blots on HARA cells co-cultured with adult mouse long bones. Further, Transforming growth factor beta (TGF-β) was identified as one of the factors in the bone microenvironment that was responsible for the up-regulation of ezrin. The identification of PTHrP and ezrin as important regulators of lung cancer bone metastasis offers new mechanistic insights into the metastasis of lung cancer and provides potential targets for the prevention and treatment of lung cancer metastasis.


Parathyroid hormone-related protein Ezrin Lung cancer Bone metastasis 



Parathyroid hormone-related protein


Humoral hypercalcemia of malignancy






Yellow fluorescent protein






In vivo imaging system


Reverse transcription-polymerase chain reaction




Small interfering RNA


Short hairpin RNA


Plasminogen activator receptor, urokinase type


Bone morphogenetic protein-2


Fibroblast growth factor


Transforming growth factor beta



The authors would like to thank Drs. Wessel Dirksen and Ramiro Toribio, Dept. of Veterinary Biosciences, The Ohio State University, for critical reading of the manuscript and valuable comments on it. This work was supported by the National Institutes of Health, Nation Cancer Institute (RO1 CA 77911, PO1 CA100730) and the National Center for Research Resources (K26 RR00168).


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Copyright information

© Springer Science + Business Media B.V. 2007

Authors and Affiliations

  • Xiyun Deng
    • 1
    • 3
  • Sarah H. Tannehill-Gregg
    • 1
    • 2
  • Murali V. P. Nadella
    • 1
  • Guangchun He
    • 1
    • 3
  • Andrea Levine
    • 1
  • Ya Cao
    • 3
  • Thomas J. Rosol
    • 1
    Email author
  1. 1.Department of Veterinary BiosciencesThe Ohio State UniversityColumbusUSA
  2. 2.Bristol-Meyers SquibbPharmaceutical Research InstituteEvansvilleUSA
  3. 3.Cancer Research InstituteXiangya School of Medicine, Central South UniversityChangsha, HunanChina

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