HeLa cells are a cell line with two unique cellular features: a short-shouldered survival curve and two peaks of radioresistance during the cell cycle phase, while their underlying mechanisms remain unclear. We herein proposed that these radiobiological features are due to a common mechanism by which radiation suppresses homologous recombination repair (HRR) in a dose-dependent manner. This radio-suppression of HRR is mediated by an intra-S checkpoint and reduces survivals of cells in S phase, especially early S phase, resulting in both short shoulder and radioresistance with two peaks in the cell cycle. This new explanation may not be limited to HeLa cells since a similar close association of these features is also observed in other type of cells.

中文翻译：

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短肩 HeLa 细胞存活曲线及其 S 期特异性敏感性的机制见解

HeLa细胞是一种具有两个独特细胞特征的细胞系：短肩生存曲线和细胞周期阶段的两个放射抗性峰值，但其潜在机制仍不清楚。我们在此提出，这些放射生物学特征是由于辐射以剂量依赖性方式抑制同源重组修复（HRR）的共同机制所致。HRR 的这种放射抑制是由 S 内检查点介导的，会降低 S 期细胞的存活率，尤其是早期 S 期，导致短肩和细胞周期中有两个峰值的放射抗性。这种新的解释可能不仅限于 HeLa 细胞，因为在其他类型的细胞中也观察到这些特征的类似密切关联。