Autophosphorylation of H2AX in a cell-specific frozen dependent way.

Effective cryopreservation is a highly desired outcome in many laboratories including clinical and research centers. Cryopreservation-induced cellular damage through necrosis and apoptosis has been well characterized. However, our knowledge of the mechanism of induction of these cell death modalities is limited. H2AX histone phosphorylation to gamma-H2AX is a DNA damage response and is an excellent indicator of DNA double stranded break formation. In this study we examined and detected significant phosphorylation of H2AX in response to cryopreservation of HELF and B16 cell lines. The data provide strong evidence of intrinsic alterations in DNA repair pathway members for which the impact is yet to be fully understood. While further investigation will be necessary to characterize this response, our findings show a clear linkage between freezing resulting in phosphorylation and activation of the key DNA repair enzyme H2AX.