Proteomic and phosphoproteomic analysis of cell response to photon and particle irradiation

ABSTRACT: The growing number of particle treatment facilities worldwide and patients treated with particles instead of X-rays marks the upcoming rearrangement of modern radiotherapy. Especially for tumors being difficult to access and for tumors that are resistant to conventional X-ray treatment particle radiotherapy is a beneficial technology. At the Heidelberg Ion Beam Therapy Center (HIT) patients are treated with this technology since 2009 as it offers clear benefits. Contrary to X-rays, which show an exponential dose decrease (after reaching electron equilibrium) with increasing tissue depth, charged particles deposit most of their energy to a small region within the tissue with a sharp dose fall-off after the so-called Bragg peak. This precise dose localization enables further dose escalation within the tumor while sparing healthy tissue. Besides physical advantages, particle radiotherapy offers additional biological advantages. In radiobiology, the term relative-biological effectiveness (RBE) is defined as the ratio of X-rays dose to an alternative irradiation modality dose which produce the same biological effect (e.g. survival or number of DSBs). While protons have a relative biological effectiveness (RBE) comparable to X-rays, carbon ions are more effective in inducing DNA damage(1, 2) and are therefore especially useful for radioresistant tumors. This is due to the fact, that carbon ions induce clustered and direct DNA damage, which is considered to be less dependent on cell cycle stage, oxygen level, genetic background and hinders DNA repair mechanisms(3–6). Nevertheless, their exact mode of action and cellular mechanisms are largely unknown. We show the first comprehensive proteomic and phosphoproteomic study elucidating the cellular response to treatment with protons, carbon ions and X-rays. We found that 2h after treatment with these radiations negligible regulation occurred at protein expression level. But 181 phosphorylation sites were deregulated by ionizing radiation contributing mainly to DNA damage response functionalities. Interestingly we found 55 phosphorylation sites being differentially regulated between the radiations. Here, we observed protons and carbon ions producing equal cellular response whereas X-rays show altered regulation for certain phosphorylation sites. A subset of 28 phosphorylation sites being involved in the DNA damage response or differentially regulated between the ionizing radiations was selected for result confirmation.

INSTRUMENT(S): LTQ Orbitrap

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Epithelial Cell

DISEASE(S): Lung Adenocarcinoma

SUBMITTER: Martin Winter  

LAB HEAD: Martina Schnölzer

PROVIDER: PXD004817 | Pride | 2017-03-20

REPOSITORIES: Pride