Phosphoproteomic profiling of tumor tissues identifies HSP27 Ser82 phosphorylation as a robust marker of early ischemia

Muhammad Saddiq Zahari, Xinyan Wu, Sneha M. Pinto, Raja Sekhar Nirujogi, Min Sik Kim, Barry Fetics, Mathew Philip, Sheri R. Barnes, Beverly Godfrey, Edward Gabrielson, Erez Nevo, Akhilesh Pandey

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Delays between tissue collection and tissue fixation result in ischemia and ischemia-associated changes in protein phosphorylation levels, which can misguide the examination of signaling pathway status. To identify a biomarker that serves as a reliable indicator of ischemic changes that tumor tissues undergo, we subjected harvested xenograft tumors to room temperature for 0, 2, 10 and 30 minutes before freezing in liquid nitrogen. Multiplex TMT-labeling was conducted to achieve precise quantitation, followed by TiO 2 phosphopeptide enrichment and high resolution mass spectrometry profiling. LC-MS/MS analyses revealed phosphorylation level changes of a number of phosphosites in the ischemic samples. The phosphorylation of one of these sites, S82 of the heat shock protein 27 kDa (HSP27), was especially abundant and consistently upregulated in tissues with delays in freezing as short as 2 minutes. In order to eliminate effects of ischemia, we employed a novel cryogenic biopsy device which begins freezing tissues in situ before they are excised. Using this device, we showed that the upregulation of phosphorylation of S82 on HSP27 was abrogated. We thus demonstrate that our cryogenic biopsy device can eliminate ischemia-induced phosphoproteome alterations, and measurements of S82 on HSP27 can be used as a robust marker of ischemia in tissues.

Original languageEnglish (US)
Article number13660
JournalScientific reports
StatePublished - Sep 2 2015

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Phosphoproteomic profiling of tumor tissues identifies HSP27 Ser82 phosphorylation as a robust marker of early ischemia'. Together they form a unique fingerprint.

Cite this