Project description:Chromosome instability (CIN) leads to aneuploidy, a state in which cells have abnormal numbers of chromosomes affecting two out of three cancers. Continuous CIN in murine T-cells was previously shown to dramatically accelerate lymphomagenesis in a p53-deficient background. Despite the predicted ongoing CIN in our mouse model, we observed whole chromosome copy number changes that affected all lymphoma cells, suggesting that CIN is somehow suppressed in the aneuploid lymphomas or that selection for frequently lost/gained chromosomes outcompetes the CIN-imposed missegregation. To distinguish between these explanations and to examine karyotype dynamics in CIN lymphoma, we used a newly developed single-cell whole genome-sequencing (scWGS) platform that provides a complete and unbiased overview of copy number variations (CNV) in individual cells. In this study we applied single cell whole genome sequencing (scWGS) to map and quantify karyotype heterogeneity in primary mouse lymphoma and human leukaemia samples. We used cohorts of Mps1f/f; Lck-Cre+, Mps1f/f; p53f/f; Lck-Cre+ and Mps1f/f; p53f/+; Lck-Cre+ mice, and Lck-Cre- mice as controls. Mice were sacrificed when exhibiting signs of lymphoma (10-14 weeks of age, typically dyspnoea due to an enlarged thymus), thymuses were harvested, and primary T-ALL single cell suspensions were frozen for subsequent single cell sequencing analysis.
Project description:Cervical intraepithelial neoplasia (CIN), also known as cervical dysplasia, is premalignant lesions of the cervical squamous cell carcinoma (CSCC) that shows abnormal growth of squamous cells in the cervix epithelium. Given the evidence suggesting that differences may exist between CIN and CSCC, we hypothesize that progression may be mediated by subpopulation selection or by acquisition of additional alterations, including gene mutations or chromosomal alterations. In this study, we analyzed cervical CIN, microinvasive carcinoma (MIC) and CSCC by whole-exome sequencing and array-comparative genomic hybridization (array-CGH) and found that CIN genomes harbored fewer mutations (especially fewer driver mutations) and copy number alterations (CNAs), suggesting that additional genomic alterations might burst onto the CIN genome at the final stage of CIN progression to CSCC or an early stage of CSCC.
Project description:Chromosomal instability (CIN), a pervasive feature of esophageal adenocarcinoma (EAC), drives tumor aggressiveness and metastasis. CIN stimulates the cGAS–STING pathway, typically linked to anti-tumor immunity. However, despite the high CIN burden in EAC, the cGAS–STING pathway remains largely intact. To address this paradox, we interrogated multiple esophageal cancer models, discovering myeloid-attracting chemokines – with CXCL8 as a prominent hit – as conserved CIN-driven targets in EAC. Using multiplexed immunofluorescence microscopy, we quantified ongoing CIN in human EAC tumors by measuring cGAS-positive micronuclei, validated by whole-genome sequencing. Coupling in situ CIN detection with single-nucleus RNA sequencing and multiplex immunophenotyping of human EAC, we link CIN to tumor-intrinsic innate immune activation, CXCL8 expression, and myeloid cell-mediated immunosuppression. In EAC patients, CIN-high, myeloid-dominated tumors correlate with poor outcomes and aberrant cGAS–STING signaling. These insights explain the counterintuitive maintenance of cGAS–STING and highlight disruption of the CIN–cGAS–inflammation axis as a potential therapeutic strategy in EAC.
Project description:Chromosomal instability (CIN), a pervasive feature of esophageal adenocarcinoma (EAC), drives tumor aggressiveness and metastasis. CIN stimulates the cGAS–STING pathway, typically linked to anti-tumor immunity. However, despite the high CIN burden in EAC, the cGAS–STING pathway remains largely intact. To address this paradox, we interrogated multiple esophageal cancer models, discovering myeloid-attracting chemokines – with CXCL8 as a prominent hit – as conserved CIN-driven targets in EAC. Using multiplexed immunofluorescence microscopy, we quantified ongoing CIN in human EAC tumors by measuring cGAS-positive micronuclei, validated by whole-genome sequencing. Coupling in situ CIN detection with single-nucleus RNA sequencing and multiplex immunophenotyping of human EAC, we link CIN to tumor-intrinsic innate immune activation, CXCL8 expression, and myeloid cell-mediated immunosuppression. In EAC patients, CIN-high, myeloid-dominated tumors correlate with poor outcomes and aberrant cGAS–STING signaling. These insights explain the counterintuitive maintenance of cGAS–STING and highlight disruption of the CIN–cGAS–inflammation axis as a potential therapeutic strategy in EAC.
Project description:Chromosomal instability (CIN), a pervasive feature of esophageal adenocarcinoma (EAC), drives tumor aggressiveness and metastasis. CIN stimulates the cGAS–STING pathway, typically linked to anti-tumor immunity. However, despite the high CIN burden in EAC, the cGAS–STING pathway remains largely intact. To address this paradox, we interrogated multiple esophageal cancer models, discovering myeloid-attracting chemokines – with CXCL8 as a prominent hit – as conserved CIN-driven targets in EAC. Using multiplexed immunofluorescence microscopy, we quantified ongoing CIN in human EAC tumors by measuring cGAS-positive micronuclei, validated by whole-genome sequencing. Coupling in situ CIN detection with single-nucleus RNA sequencing and multiplex immunophenotyping of human EAC, we link CIN to tumor-intrinsic innate immune activation, CXCL8 expression, and myeloid cell-mediated immunosuppression. In EAC patients, CIN-high, myeloid-dominated tumors correlate with poor outcomes and aberrant cGAS–STING signaling. These insights explain the counterintuitive maintenance of cGAS–STING and highlight disruption of the CIN–cGAS–inflammation axis as a potential therapeutic strategy in EAC.
Project description:Chromosomal instability (CIN), defined as an increased occurrence of chromosome segregation errors during cell division, is a prominent form of genomic instability (Bakhoum and Avi Landau, 2017). It is the major cause of aneuploidy, an imbalanced complement of whole chromosomes or chromosome arms, which is the most prevalent genetic alteration in human cancers (Vasudevan et al., 2021; Santaguida and Amon, 2015). Importantly, aneuploidy is commonly associated with ongoing CIN through consecutive cell divisions (Shelzer et al. 2011; Passerini et al., 2016), resulting in intratumor genetic heterogeneity, a central driver of cancer evolution and therapeutic resistance (Sansregret et al., 2018; Ben-David and Amon, 2019). Indeed, aneuploidy has been shown to act both as a tumor suppressor and as a tumor initiator (Weaver et al., 2007; Silk et al., 2013; Vasudevan et al., 2020), most likely depending on the specific chromosomes that are gained or lost (Ben-David et al., 2011; Sack et al., 2018; Adell et al., 2023). Despite the ubiquitous presence of CIN in several aneuploid cancer types and its clinical relevance, its presence in B-cell acute lymphoblastic leukemia (B-ALL) remains largely unexplored owing to the impaired proliferation of leukemic cells in vitro and the lack of reliable experimental models to comprehensively assess chromosome segregation in vivo. B-ALL is the most frequent childhood cancer, with 75% of cases occurring in children under 6 years of age, and it is characterized by the accumulation of highly proliferative immature B-cell precursors in the bone marrow (BM) (Hunger and Mullighan, 2015). The presence of CIN and its contribution to aneuploid cB-ALL progression is largely unknown due to the lack of preclinical models to study actively dividing cells. Accordingly, studies of CIN in cB-ALL are limited to the characterization of chromosomal copy-number heterogeneity (chr-CNH) in primary cB-ALL samples, but there is controversy over its presence due to the different techniques used to assess karyotype variability (Raimondi et al., 1996; Talamo et al., 2010; Alpar et al., 2014; Heerema et al.; 2007; Ramos-Muntada et al., 2022). Here, we explored the presence and the levels of CIN in different clinically-relevant aneuploid subtypes of cB-ALL using single-cell whole-genome sequencing (WGS) of primary samples to reliably assess chr-CNH, and by generating a large cohort of PDX models from primary cB-ALL samples (cB-ALL-PDX). Our results in cB-ALL-PDX models revealed variable levels of CIN in aneuploid cB-ALL subtypes, which significantly correlate with intraclonal karyotype heterogeneity and with disease progression. Additionally, mass-spectrometry analyses of cB-ALL-PDX samples revealed a CIN “signature” enriched in mitosis and chromosome segregation regulatory pathways. We speculate that this signature identifies adaptive mechanisms to ongoing CIN in aneuploid cB-ALL cells, which displayed a transcriptional signature characterized by an impaired mitotic spindle as observed by RNA-sequencing (RNA-Seq) analyses of a large cohort of primary cB-ALL patient samples. Our work might help to improve stratification of patients with cB-ALL with different levels of CIN who could benefit in the future from new therapeutic approaches aiming to target ongoing CIN.
Project description:Telomere dysfunction drives chromosomal instability (CIN) during the transition from benign adenoma to malignant adenocarcinoma. While CIN provides a mutator mechanism for cancer- relevant genomic events, its role in shaping tumor biology during carcinogenesis is not well understood. Here, we explored the molecular and biological impact of telomere dysfunction and associated CIN in vivo in a faithful model of CRC. In vivo lineage tracing revealed that CIN increased the rate of neoplastic cell clonal expansion through accelerated differentiation of neighboring stem cells, resulting in increased number of adenomas and decreased survival in CIN-high Apcmin mice. Mechanistically, CIN represses EZH2 leading to upregulation of secreted Wnt antagonists, which resulted in a growth advantage to CIN-high neoplastic cells. Correspondingly, pharmacological activation of intrinsic WNT signaling enhanced intestinal stem cells fitness, leading to reduced neoplastic cell clonal expansion and adenoma burden. Thus, the CIN-EZH2-WNT axis enhances intestinal cancer initiation in the nascent tumor microenvironment, providing a preventive strategy for patients harboring germline APC mutations.
Project description:Chromosomal instability (CIN) and epigenetic alterations, major drivers of tumor evolution, contribute to breast cancer metastasis. Whether CIN is epigenetically regulated in metastatic cells is poorly understood. Here we show that EZH2 expression is highly correlated with genomic copy number alterations across human breast tumors. Consistently, increased expression of EZH2 histone methyl transferase is associated with elevated CIN in triple negative breast cancer (TNBC) metastasis initiating cells. Genetic or pharmacological inhibition of EZH2 suppresses CIN whereas forced overexpression of EZH2 in otherwise non-transformed cells promotes chromosome segregation errors. Integrated global chromatin and transcriptome profiling identified Tankyrase (TNKS), a multifunctional poly (ADP ribose) polymerase (PARP), as a direct target of EZH2 transcriptional suppressive activity. Strikingly, depletion of TNKS was sufficient to abrogate the ability of EZH2 inhibition to suppress CIN. EZH2-mediated suppression of TNKS induced centrosome amplification and multipolar mitosis which often clustered into pseudo-bipolar mitotic spindles exhibiting chromosome segregation defects. Our work establishes a previously unappreciated epigenetic regulatory mechanisms of CIN and suggests that CIN suppression might be an important component of epigenetic modifying therapies such as EZH2 inhibitors which are currently in clinical use.
Project description:Chromosomal instability (CIN), an ongoing rate of chromosome missegregation during mitosis, is a defining feature of cancer. However, high chromosomal aberrations are detrimental for cell fitness. Here we investigated mechanisms allowing lethal prostate cancer (PCa) to tolerate and survive increasing CIN. Transcriptomic and proteomic analysis of patient datasets and experimental models showed a concomitant increase of CIN and cell division fidelity kinases in lethal PCa. Functional studies identified MASTL as a key kinase to which therapy-resistant PCa cells become addicted to restrain lethal CIN and ensure survival. Combined analysis of transcription factors increased in high CIN PCa patient datasets with detailed promoter analysis identified that MASTL expression is regulated by the Androgen Receptor variant 7 (AR-V7) and E2F7. Finally, targeting MASTL addiction vulnerability in vivo using the small molecule inhibitor GKI-1, improves survival of pre-clinical models. These findings provide proof-of-concept for exploiting CIN levels as a therapeutic approach in cancer.