Validation of heat shock protein 70 as a tumor-specific biomarker for monitoring the outcome of radiation therapy in tumor mouse models

Int J Radiat Oncol Biol Phys. 2014 Mar 1;88(3):694-700. doi: 10.1016/j.ijrobp.2013.11.008.

Abstract

Purpose: Tumor cells, in contrast to normal cells, frequently overexpress heat shock protein 70 (Hsp70) in the cytosol, present it on their cell surface, and actively release it. Therefore, soluble Hsp70 (sHsp70) was investigated as a potential tumor biomarker for monitoring the outcome of radiation therapy.

Methods and materials: Plasma from mice bearing membrane Hsp70 (mHsp70)-positive FaDu human squamous cell carcinoma of the head and neck and spontaneous pancreatic ductal adenocarcinoma (PDAC) was investigated. A cohort of mice with FaDu tumors (0.32 cm(3)) was irradiated with 30 Gy, and plasma was collected 24 hours after irradiation, after the tumors had shrunk to 50% of their starting volume and after complete remission. sHsp70 levels in the plasma were quantified by enzyme-linked immunosorbent assay.

Results: sHsp70 levels were significantly higher in the blood of tumor-bearing mice than that of control animals. A correlation between increasing sHsp70 plasma levels and tumor volume in the range of 0.01 cm(3) to 0.66 cm(3) was observed. Radiation-induced regression of the tumors was associated with significantly decreased sHsp70 levels, which returned to the level of control animals after complete remission.

Conclusion: We propose sHsp70 as an innovative biomarker for detecting tumors and for monitoring the clinical outcome of radiation therapy in cancer patients.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Animals
  • Biomarkers, Tumor / blood*
  • Carcinoma, Pancreatic Ductal / blood*
  • Carcinoma, Pancreatic Ductal / pathology
  • Carcinoma, Pancreatic Ductal / radiotherapy
  • Carcinoma, Squamous Cell / blood*
  • Carcinoma, Squamous Cell / pathology
  • Carcinoma, Squamous Cell / radiotherapy
  • Cell Line, Tumor
  • Disease Models, Animal*
  • Female
  • HSP70 Heat-Shock Proteins / blood*
  • Head and Neck Neoplasms / blood*
  • Head and Neck Neoplasms / pathology
  • Head and Neck Neoplasms / radiotherapy
  • Heterografts
  • Humans
  • Mice
  • Pancreatic Neoplasms / blood*
  • Pancreatic Neoplasms / pathology
  • Pancreatic Neoplasms / radiotherapy
  • Radiation Dosage
  • Spheroids, Cellular / metabolism
  • Spheroids, Cellular / radiation effects
  • Treatment Outcome
  • Tumor Burden

Substances

  • Biomarkers, Tumor
  • HSP70 Heat-Shock Proteins