Carbon-ion radiotherapy of human lung cancer

ABSTRACT: Carbon-ion irradiation is an emerging therapeutic option for several tumor entities including lung cancer. Well oxygenated tumor areas compared to a hypoxic environment favor therapeutic photon irradiation efficiency of solid tumors due to increased amounts of DNA damage. The resistance of hypoxic tumor areas towards photon irradiation is enhanced through increased HIF-1 signaling. Here, we compared the effects of oxygen and HIF 1 after photon and carbon-ion irradiation with biological equivalent doses in a human non-small lung cancer model. In hypoxia compared to normoxia, A549 and H1299 cells displayed improved survival after photon irradiation. Knockdown of HIF-1M-NM-1 combined with photon irradiation synergistically delayed tumor growth in vivo. Photon irradiation induced HIF-1M-NM-1 and several of its target genes such as PDK1, GLUT-1, LDHA, and VEGF with subsequent enhanced tumor angiogenesis in vivo, a signaling cascade that was not targeted by carbon-ion irradiation. We present evidence that photons but not carbon-ions induce HIF-1M-NM-1 via mTOR pathway. Importantly, after carbon-ion irradiation in vivo, we observed substantial downregulation of HIF-1M-NM-1 and a drastically delayed tumor growth indicating a considerable higher relative biological effectiveness (RBE) than anticipated from the cell survival data. In sum, our results demonstrate that carbon-ions mediate an improved therapeutic response of tumor treatment compared to photon irradiation that is independent of cell oxygenation and HIF-1 signaling. 16 independent cell cultures were used. Each culture was split into an irradiated and a control plate, yieldin a total of 16 paired samples. Paired samples were analysed in 16 two-color hybridizations. Factors time (after irradiation) with levels 1h and 4h and factor radiation quality with levels C12 and X-rays were analyzed. Each of the 2x2 combinations was analyzed in 4 independent experiments.

ORGANISM(S): Homo sapiens

SUBMITTER: Jochen Wilhelm 

PROVIDER: E-GEOD-45403 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress