Reoxygenation and Repopulation of Tumor Cells after Ablative Hypofractionated Radiotherapy (SBRT and SRS) in Murine Tumors.

Reoxygenation and Repopulation of Tumor Cells after Ablative Hypofractionated Radiotherapy (SBRT and SRS) in Murine Tumors.
Radiat Res. 2019 Jun 12;:
Authors: Song CW, Griffin RJ, Lee YJ, Cho H, Seo J, Park I, Kim HK, Kim DH, Kim MS, Dusenbery KE, Cho LC
Abstract
In this work, we investigated the change in tumor microenvironment caused by semi-ablative high-dose irradiation and its implication on tumor cell survival, reoxygenation of hypoxic cells and repopulation in FSaII tumors grown subcutaneously in the hind legs of C3H mice. Tumors were exposed to 10-30 Gy of X-ray radiation in a single exposure, and the vascularity and blood perfusion were assessed based on the levels of CD31 expression and Hoechst 33342 perfusion, respectively. The tumor hypoxia was assessed by staining for pimonidazole adduct formation and the expression of hypoxia-inducible factor-1α (HIF-1α) and carbonic anhydrase 9 (CA9). Tumor cell survival was determined using in vivo-in vitro excision assay method. The proportion of hypoxic cells in the tumor was determined from the surviving cell fraction in tumors exposed to a test dose under aerobic and hypoxic conditions. Radiation expsoure markedly reduced the functional vascularity and blood perfusion, and profoundly increased the expression of HIF-1α and CA9 pointing to an increase in tumor hypoxia. The overall clonogenic cell survival progressively decreased during 2-5 days postirradiation, most likely due to...

Source: Radiation Research - June 11, 2019 Category: Physics Authors: Song CW, Griffin RJ, Lee YJ, Cho H, Seo J, Park I, Kim HK, Kim DH, Kim MS, Dusenbery KE, Cho LC Tags: Radiat Res Source Type: research