College of Pharmacy, Sookmyung Women's University, Seoul 04310, Republic of Korea.
Muscle Physiome Research Center, Sookmyung Women's University, Seoul 04310, Republic of Korea.
Int J Mol Sci. 2023 May 31;24(11):9530. doi: 10.3390/ijms24119530.
We investigated the role of TONSL, a mediator of homologous recombination repair (HRR), in stalled replication fork double-strand breaks (DSBs) in cancer. Publicly available clinical data (tumors from the ovary, breast, stomach and lung) were analyzed through KM Plotter, cBioPortal and Qomics. Cancer stem cell (CSC)-enriched cultures and bulk/general mixed cell cultures (BCCs) with RNAi were employed to determine the effect of loss in cancer cell lines from the ovary, breast, stomach, lung, colon and brain. Limited dilution assays and ALDH assays were used to quantify the loss of CSCs. Western blotting and cell-based homologous recombination assays were used to identify DNA damage derived from TONSL loss. was expressed at higher levels in cancer tissues than in normal tissues, and higher expression was an unfavorable prognostic marker for lung, stomach, breast and ovarian cancers. Higher expression of is partly associated with the coamplification of and , suggesting its oncogenic role. The suppression of using RNAi revealed that it is required in the survival of CSCs in cancer cells, while BCCs could frequently survive without . dependency occurs through accumulated DNA damage-induced senescence and apoptosis in -suppressed CSCs. The expression of several other major mediators of HRR was also associated with worse prognosis, whereas the expression of error-prone nonhomologous end joining molecules was associated with better survival in lung adenocarcinoma. Collectively, these results suggest that TONSL-mediated HRR at the replication fork is critical for CSC survival; targeting TONSL may lead to the effective eradication of CSCs.
我们研究了 TONSL 在同源重组修复（HRR）介导的停滞复制叉双链断裂（DSBs）中的作用，TONSL 是同源重组修复（HRR）的中介物。通过 KM Plotter、cBioPortal 和 Qomics 分析了公开可用的临床数据（来自卵巢、乳腺、胃和肺的肿瘤）。采用癌症干细胞（CSC）富集培养物和批量/普通混合细胞培养物（BCC）进行 RNAi，以确定卵巢、乳腺、胃、肺、结肠和脑癌细胞系中 缺失的影响。采用有限稀释测定和 ALDH 测定来定量 CSCs 的缺失。采用 Western blot 和基于细胞的同源重组测定来鉴定源自 TONSL 缺失的 DNA 损伤。在癌症组织中表达水平高于正常组织，高表达是肺癌、胃癌、乳腺癌和卵巢癌不利的预后标志物。TONSL 表达水平较高与 和 共扩增部分相关，提示其致癌作用。使用 RNAi 抑制 发现，它是癌症干细胞在癌细胞中存活所必需的，而 BCC 通常可以在没有 的情况下存活。TONSL 依赖性是通过在抑制 的 CSCs 中积累的 DNA 损伤诱导的衰老和凋亡来实现的。几种其他主要 HRR 介质的表达也与预后不良相关，而易错非同源末端连接分子的表达与肺腺癌的更好生存相关。总之，这些结果表明，TONSL 介导的复制叉 HRR 对 CSC 存活至关重要；靶向 TONSL 可能导致 CSCs 的有效根除。
