Robust-to-fragile transitions of a phase-separated mitotic organelle in triple-negative breast cancer

项目摘要/摘要 非整倍体和杂合性丢失是由姊妹染色体引起的高度普遍的染色体异常。 有丝分裂过程中的染色单体分离错误。非整倍体在三阴性乳腺中尤其常见。 癌症，非整倍体细胞的生长是由TP53的近乎普遍的丢失所允许的，正常情况下 监测基因组的完整性。我们团队之前的工作已经将乳腺癌的非整倍体表型联系起来 到有丝分裂转录因子诱导的基因网络水平的丰度变化，这些转录因子是慢性的 在肿瘤中升高。这些转录因子的靶基因位于基因的上游和下游 染色体乘客复合体(CPC)，一个正确的纺锤体组装的四种蛋白质传感器和一个 修理。CPC必须定位于着丝粒内侧，并在微管错误时自动激活 附在这里。我们最近发现，CPC在中期积累到一个临界浓度，从而导致它 以液体冷凝物的形式相分离。CPC相分离可能会赋予函数的健壮性，但 癌症通过改变多个调节器和效应器的丰度来设法绕过这个检查点 共同导致细胞进入染色体不稳定状态。我们的目标是揭开这个复杂的 在肿瘤中发现的网络调节因子的丰度失衡强调了CPC对 内着丝粒，并在乳腺癌或前驱病变中产生染色体不稳定性。领先者 假说认为，在有丝分裂过程中，相分离的CPC通过缓冲小到 适度失衡(存储)，并在阈值失衡达到 达到(卸货)。我们将使用生化反应-扩散模型来检验这一假说 受管制的CPC相分离，将根据从马赛克衍生的初级乳腺器官量身定做 三阴性乳腺癌的GEMM和通过标准诊断扩展到临床样本 化验。具体目标是1)开发和验证CPC招募的空间系统模型 分离易患癌症的乳腺器官中的相分离并预测关键的网络失衡； 2)通过定量扰动三重不平衡来测试临界网络不平衡的不稳定性产生潜力。 体内阴性的乳腺癌前病变；以及3)利用常规临床诊断预测可用药 任何原发乳腺癌的染色体不稳定特征。特定于患者的系统级模型 非整倍体易感性将提名网络中的激酶抑制剂，这些抑制剂被预测将细胞从 对脆弱的种族隔离忠诚度很强。

PROJECT ABSTRACT/SUMMARY Aneuploidy and loss of heterozygosity are highly prevalent chromosome aberrations caused by sister- chromatid segregation errors during mitosis. Aneuploidy is especially common in triple-negative breast cancers, where outgrowth of aneuploid cells is permitted by the near-universal loss of TP53 that normally surveils genomic integrity. Prior work from our team has connected the aneuploid phenotype in breast cancer to network-level abundance changes in genes induced by mitotic transcription factors, which are chronically elevated in tumors. The target genes of these transcription factors reside upstream and downstream of the chromosome passenger complex (CPC), a four-protein sensor of proper spindle assembly and a mediator of repair. The CPC must localize to the inner centromere and auto-activate when microtubules are incorrectly attached. We recently found that the CPC accumulates during metaphase to a critical concentration causing it to phase separate as a liquid condensate. CPC phase separation likely confers robustness of function, yet cancers manage to bypass this checkpoint by changing the abundance of multiple regulators and effectors that together cause cells to enter a state of chromosome instability. Our objective is to unravel how the complex abundance imbalances of network regulators found in tumors stress the robust localization of the CPC to the inner centromere and generate chromosome instability in breast cancers or precursor lesions. The leading hypothesis is that phase-separated CPC acts as a “phenotypic capacitor” during mitosis by buffering small to moderate imbalances (storage) and unleashing dramatic rearrangements when a threshold imbalance is reached (discharge). We will test this hypothesis using biochemical reaction-diffusion models of spatially regulated CPC phase separation, which will be tailored to primary mammary organoids derived from a mosaic GEMM of triple-negative mammary cancer and extended to clinical samples through standard diagnostic assays. The specific aims are to 1) develop and validate a spatial systems model of CPC recruitment that isolates phase separation and predicts critical network imbalances in cancer-predisposed mammary organoids; 2) test the instability-generating potential of critical network imbalances by quantitatively perturbing triple- negative mammary premalignancies in vivo; and 3) leverage routine clinical diagnostics to predict druggable chromosomal instability signatures in any primary breast cancer. Patient-specific, systems-level models of aneuploidy susceptibility will nominate kinase inhibitors in the network that are predicted to shift cells from robust to fragile states of segregation fidelity.