The use of  label-free LC-MS/MS approach to identify signaling pathways associated with prostate cancer radioresistance — ASN Events
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The use of  label-free LC-MS/MS approach to identify signaling pathways associated with prostate cancer radioresistance (#211)

Lei Chang 1 2 , Valerie Wasinger 3 , Peter Graham 1 2 , Jingli Hao 1 2 , Jie Ni 1 2 , Julia Beretov 1 2 , Joseph Bucci 1 2 , Paul Cozzi 2 4 , John Kearsley 1 2 , Yong Li 1 2
  1. Cancer Care Centre, St George Hospital, Kogarah, NSW, Australia
  2. St George Clinical School, Faculty of Medicine,UNSW, Kensington, NSW, Australia
  3. Bioanalytical Mass Spectrometry facility, Mark Wainwright Analytical centre, UNSW, Kingsford, NSW, Australia
  4. Department of Surgery, St George Hospital, Kogarah, NSW, Australia

Aim: Radioresistance is still the major problem in current prostate cancer (CaP) radiation therapy (RT). Our objective in this study was to identify related signaling pathways and determine differential proteins in CaP radioresistant (RR) cell lines for biomarker candidates using a LC-MS/MS proteomic approach.

Methods: Three CaP-RR cell lines (PC-3RR, DU145 and LNCaPRR) were developed in our lab. After extracting and digesting the proteins from CaP-RR (PC-3RR and LNCaPRR) and CaP-control (PC-3 and LNCaP) cells. Samples were cleaned prior to MS using 3 passes through a C18 Stage-tip (proxeon) with elution in between passes. LC-MS/MS using the LTQ Orbitrap Velos ETD (Thermo Scientific, US) was used for a relative and quantitative analysis. The findings were statistically analyzed using Progenesis LC-MS software (Non-Linear Dynamics, UK) and all MS/MS ions filed were searched using the Mascot search engine for peptide and protein identification. The results were searched against the human non-redundant NCBInr database.

Results: Total 513 proteins were found to be statistically significant differences between CaP-RR and CaP-control cells (p≤ 0.05, fold differences>3, sort using >80% power). Of these 513 proteins, 186 proteins were up-regulated while 120 were down-regulated in PC-3RR cells. Whereas, 207 differential proteins, 110 were found higher while 97 proteins were lower in LNCaPRR cells compared to LNCaP cells. The several identified proteins are associated with CaP metastasis, progression, signaling pathways and radoresistance.

Conclusions: Significant proteins were identification in the CaP-RR. These proteins are associated with CaP radioresistance and will be validated in human CaP-RR tissues. The characterization of these proteins is worthwhile in the future studies. 

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