Fernandez Brianna, Passanisi Victor, Ashraf Humza M, Spencer Sabrina L
Department of Biochemistry and BioFrontiers Institute, University of Colorado Boulder, Boulder, CO 80303, USA.
bioRxiv. 2025 May 14:2025.05.13.653730. doi: 10.1101/2025.05.13.653730.
Quiescence (reversible cell-cycle arrest) and senescence (irreversible arrest) are challenging to distinguish due to a lack of specific biomarkers, yet both arise simultaneously after chemotherapy. While senescence suppresses tumors by limiting proliferation and recruiting the immune system, quiescent cancer cells evade future therapies and may resume proliferation. Here, we pair time-lapse imaging of cell-cycle dynamics with single-cell RNA-sequencing after etoposide treatment to differentiate these states, linking heterogeneous cell-cycle phenotypes to the transcriptomic landscape. We identify diverse senescent types (senotypes) and link them to two arrest pathways - a gradual path arising after a standard mitosis-to-G0 transition, and a rarer but direct path driven by a mitotic slip. Using pseudotime trajectory analysis, we find that senescent phenotypes begin to manifest early and gradually along the first trajectory, even in shallow quiescent cells. These data support a model wherein, following chemotherapy, quiescence and senescence exist on a continuum of cell-cycle withdrawal at a transcriptome-wide level.
由于缺乏特异性生物标志物，静止（可逆性细胞周期停滞）和衰老（不可逆性停滞）难以区分，但二者在化疗后会同时出现。衰老通过限制增殖和招募免疫系统来抑制肿瘤，而静止的癌细胞则逃避未来的治疗并可能恢复增殖。在这里，我们在依托泊苷处理后，将细胞周期动态的延时成像与单细胞RNA测序相结合，以区分这些状态，将异质性细胞周期表型与转录组景观联系起来。我们识别出不同的衰老类型（衰老型），并将它们与两种停滞途径联系起来——一种是在标准的有丝分裂到G0期转变后出现的渐进途径，另一种是由有丝分裂滑脱驱动的较罕见但直接的途径。使用伪时间轨迹分析，我们发现衰老表型即使在浅静止细胞中也会沿着第一条轨迹早期开始并逐渐显现。这些数据支持了一个模型，即在化疗后，静止和衰老在全转录组水平的细胞周期退出连续体上存在。
