近日,，來自伯克利國家實驗室等處的科學家發(fā)現,，來自質子的輻射可以增強腫瘤發(fā)生的過程,，該項研究或許使得我們開發(fā)出更好的方法來保護宇航員免受太空輻射。野味我們更好地理解輻射給人體帶來的影響提供基礎,。
質子是帶電荷的亞原子顆粒,，也是主要的宇宙輻射的輻射來源,，研究者Francis表示,，我們的研究發(fā)現了，在輻射治療期間低劑量的質子輻射所引發(fā)的腫瘤發(fā)生風險,。而且質子輻射可以增強進行性腫瘤發(fā)生的過程,，這個過程被稱為上皮間質變遷（EMT），其和癌癥發(fā)展直接相關,。EMT同樣和輻射誘導的纖維化有關,。
值得注意的是，這項研究揭示了單獨的質子可以誘發(fā)正常人類上皮細胞的EMT相關改變,。盡管在太空中接受的輻射相比放療低的多,。低劑量的質子或許也可以激發(fā)EMT并且導致潛在的不利作用。相關研究成果刊登在了近日的國際雜志PLoS One上,。（生物谷Bioon.com）
編譯自：NASA Investigates Proton Radiation Effects On Cells
doi:10.1371/journal.pone.0041249
PMC:
PMID:
Protons Sensitize Epithelial Cells to Mesenchymal Transition
Minli Wang1, Megumi Hada1, Janapriya Saha1, Deepa M. Sridharan2, Janice M. Pluth2, Francis A. Cucinotta3*
Proton radiotherapy has gained more favor among oncologists as a treatment option for localized and deep-seated tumors. In addition, protons are a major constituent of the space radiation astronauts receive during space flights. The potential for these exposures to lead to, or enhance cancer risk has not been well studied. Our objective is to study the biological effects of low energy protons on epithelial cells and its propensity to enhance transforming growth factor beta 1 (TGFβ1)-mediated epithelial-mesenchymal transition (EMT), a process occurring during tumor progression and critical for invasion and metastasis. Non-transformed mink lung epithelial cells (Mv1Lu) and hTERT- immortalized human esophageal epithelial cells (EPC) were used in this study. EMT was identified by alterations in cell morphology, EMT-related gene expression changes determined using real-time PCR, and EMT changes in specific cellular markers detected by immunostaining and western blotting. Although TGFβ1 treatment alone is able to induce EMT in both Mv1Lu and EPC cells, low energy protons (5 MeV) at doses as low as 0.1 Gy can enhance TGFβ1 induced EMT. Protons alone can also induce a mild induction of EMT. SD208, a potent TGFβ Receptor 1 (TGFβR1) kinase inhibitor, can efficiently block TGFβ1/Smad signaling and attenuate EMT induction. We suggest a model for EMT after proton irradiation in normal and cancerous tissue based on our results that showed that low and high doses of protons can sensitize normal human epithelial cells to mesenchymal transition, more prominently in the presence of TGFβ1, but also in the absence of TGFβ1.
