Biology subjects

Okimoto, R. A.

Publications and source records attributed to Okimoto, R. A..

6 recordsLinked to original sources

bioRxiv2025

First Generation Tools for the Modeling of Capicua (CIC) - Family Fusion Oncoprotein-Driven Cancers

Clinical divergence between patients harboring CIC-rearrangements is frequently observed. For example, the prototypical CIC::DUX4 fusion associates with soft tissue tumors while CIC::NUTM1 fusions typically localize to the CNS (brain/spinal cord). The basis for these differences is poorly understood due to a lack of molecular tools. To address this need, we generated patient-informed, synthetic coding sequences for CIC::NUTM1, CIC::LEUTX, and ATXN1::DUX4 and validated them in structure-function studies. We found that CIC::NUTM1 drives a transcriptional program distinct from that of CIC::DUX4 due to a C-terminal NUTM1 functional domain, CIC::LEUTX weakly activates CIC target genes through LEUTX transactivation sequences, and ATXN1::DUX4 upregulates CIC target genes via the ATXN1 AXH domain. Our findings indicate that the CIC fusion binding partner may alter overall fusion oncoprotein activity. Thus, these first generation synthetic tools provide an unprecedented resource to study CIC-family fusions beyond CIC::DUX4 and allow for the dissection of this rare subgroup of cancers. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=195 SRC="FIGDIR/small/653825v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1c1cf27org.highwire.dtl.DTLVardef@1073faforg.highwire.dtl.DTLVardef@e61455org.highwire.dtl.DTLVardef@140e952_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2024

The Capicua C1 Domain is Required for Full Activity of the CIC::DUX4 Fusion Oncoprotein

Rearrangements between genes can yield neomorphic fusions that drive oncogenesis. Fusion oncogenes are made up of fractional segments of the partner genes that comprise them, with each partner potentially contributing some of its own function to the nascent fusion oncoprotein. Clinically, fusion oncoproteins driving one diagnostic entity are typically clustered into a single molecular subset and are often treated a similar fashion. However, knowledge of where specific fusion breakpoints occur in partner genes, and the resulting retention of functional domains in the fusion, is an important determinant of fusion oncoprotein activity and may differ between patients. This study investigates this phenomena through the example of CIC::DUX4, a fusion between the transcriptional repressor capicua (CIC) and the double homeobox 4 gene (DUX4), which drives an aggressive subset of undifferentiated round cell sarcoma. Using a harmonized dataset of over 100 patient fusion breakpoints from the literature, we show that most bona fide CIC::DUX4 fusions retain the C1 domain, which is known to contribute to DNA binding by wild type CIC. Mechanistically, deletion or mutation of the C1 domain reduces, but does not eliminate, activation of CIC target genes by CIC::DUX4. We also find that expression of C1-deleted CIC::DUX4 is capable of exerting intermediate transformation-related phenotypes compared with those imparted by full-length CIC::DUX4, but was not sufficient for tumorigenesis in a subcutaneous mouse model. In summary, our results suggest a supercharging role for the C1 domain in the activity of CIC::DUX4. Significance StatementFusion oncogenes are neomorphic entities comprised of fractional coding sequences from two partner genes that have been inappropriately rearranged. The functional domains contributed by the partner genes shape the function of the resulting fusion. We use CIC::DUX4, a transcription factor fusion that drives an ultra-rare soft tissue sarcoma, to explore how preferential retention of a partner gene domain may influence the activity of the overall fusion. Our results indicate that the capicua C1 domain is retained in most CIC::DUX4 transcripts and is required for full activity of the CIC::DUX4 oncoprotein. We demonstrate that knowledge of where breakpoints occur and the resulting impact this has on the retention of functional domains can teach us about fusion behavior.

cancer biology↗

bioRxiv2021

Transcriptional fidelity enhances cancer cell line selection in pediatric cancers

Multi-omic technologies have allowed for comprehensive profiling of patient-derived tumor samples and the cell lines that are intended to model them. Yet, our understanding of how cancer cell lines reflect native pediatric cancers in the age of molecular subclassification remains unclear and represents a clinical unmet need. Here we use Treehouse public data to provide an RNA-seq driven analysis of 799 cancer cell lines, focusing on how well they correlate to 1,655 pediatric tumor samples spanning 12 tumor types. For each tumor type we present a ranked list of the most representative cell lines based on correlation of their transcriptomic profiles to those of the tumor. We found that most (8/12) tumor types best correlated to a cell line of the closest matched disease type. We furthermore showed that inferred molecular subtype differences in medulloblastoma significantly impacted correlation between medulloblastoma tumor samples and cell lines. Our results are available as an interactive web application to help researchers select cancer cell lines that more faithfully recapitulate pediatric cancer.

cancer biology↗

bioRxiv2021

WEE1 kinase is a therapeutic vulnerability in CIC-DUX4 undifferentiated sarcoma.

CIC-DUX4 rearrangements define an aggressive and chemotherapy-insensitive subset of undifferentiated sarcomas. The CIC-DUX4 fusion drives oncogenesis through direct transcriptional upregulation of cell cycle and DNA replication genes. Notably, CIC-DUX4- mediated CCNE1 upregulation compromises the G1/S transition, conferring a potential survival dependence on the G2/M cell cycle checkpoint. Through an integrative transcriptional and kinase activity screen using patient-derived specimens, we now show that CIC-DUX4 sarcomas depend on the G2/M checkpoint regulator, WEE1, as an adaptive survival mechanism. Specifically, CIC-DUX4 sarcomas depend on WEE1 activity to limit DNA damage and unscheduled mitotic entry. Consequently, genetic or pharmacologic WEE1 inhibition in vitro and in vivo leads to rapid DNA damage-associated apoptotic induction of patient-derived CIC-DUX4 sarcomas. Thus, we identify WEE1 as an actionable therapeutic vulnerability in CIC-DUX4 sarcomas.

cancer biology↗

bioRxiv2020

Continuous lineage recording reveals rapid, multidirectional metastasis in a lung cancer xenograft model in mouse

Cancer progression is characterized by rare, transient events which are nonetheless highly consequential to disease etiology and mortality. Detailed cell phylogenies can recount the history and chronology of these critical events - including metastatic seeding. Here, we applied our Cas9-based lineage tracer to study the subclonal dynamics of metastasis in a lung cancer xenograft mouse model, revealing the underlying rates, routes, and drivers of metastasis. We report deeply resolved phylogenies for tens of thousands of metastatically disseminated cancer cells. We observe surprisingly diverse metastatic phenotypes, ranging from metastasis-incompetent to aggressive populations. These phenotypic distinctions result from pre-existing, heritable, and characteristic differences in gene expression, and we demonstrate that these differentially expressed genes can drive invasiveness. Furthermore, metastases transit via diverse, multidirectional tissue routes and seeding topologies. Our work demonstrates the power of tracing cancer progression at unprecedented resolution and scale. One Sentence SummarySingle-cell lineage tracing and RNA-seq capture diverse metastatic behaviors and drivers in lung cancer xenografts in mice.

cancer biology↗

bioRxiv2018

The CIC-DUX4 fusion oncoprotein drives metastasis and tumor growth via distinct downstream regulatory programs and therapeutic targets in sarcoma

Transcription factor fusion genes create oncoproteins that drive oncogenesis, and represent challenging therapeutic targets. Understanding the molecular targets by which such fusion oncoproteins promote malignancy offers an approach to develop rational treatment strategies to improve clinical outcomes. CIC-DUX4 is a transcription factor fusion that defines certain undifferentiated round cell sarcomas with high metastatic propensity and poor clinical outcomes. The molecular targets regulated by the CIC-DUX4 oncoprotein that promote this aggressive malignancy remain largely unknown. We show that increased expression of ETV4 and CCNE1 occurs via neo-morphic, direct effects of CIC-DUX4 and drives tumor metastasis and survival, respectively. We demonstrate a molecular dependence on the CCNE-CDK2 cell cycle complex that renders CIC-DUX4 tumors sensitive to inhibition of the CCNE-CDK2 complex, highlighting a therapeutic strategy for CIC-DUX4 tumors. Our findings highlight a paradigm of functional diversification of transcriptional repertoires controlled by a genetically-aberrant transcriptional regulator, with therapeutic implications.

cancer biology↗