Biology subjects

Winkler, R.

Publications and source records attributed to Winkler, R..

8 recordsLinked to original sources

bioRxiv2026

Targeting IGF2BP1 Creates a Mitotic Vulnerability in Colorectal Carcinoma

Background Mitotic dysregulation is a common feature of colorectal cancer (CRC), yet the contribution of post-transcriptional mechanisms remain incompletely understood. We investigated how the oncofetal RNA-binding protein IGF2BP1 supports mitotic integrity and exposes therapeutic vulnerabilities in CRC. Methods We integrated patient cohort analyses with genetic and pharmacological perturbation of IGF2BP1, transcriptomics, proteomics, RNA-binding assays and functional studies. Xenografts assessed tumor formation, while BTYNB-paclitaxel responses were examined in CRC cell lines and patient-derived organoids. Results IGF2BP1 expression was elevated in CRC, increased with tumor stage, and associated with poor survival and proliferative gene signatures. Genetic depletion or pharmacological inhibition of IGF2BP1 impaired cell viability, induced mitotic abnormalities, and promoted apoptosis, whereas its re-expression enhanced tumor formation in vivo. Integrated molecular analyses identified the chromosomal passenger complex (CPC) as a previously unrecognized downstream target of IGF2BP1. IGF2BP1 bound transcripts encoding CPC components and its depletion consistently reduced their expression across multiple cancer cell models. BTYNB disrupted IGF2BP1 association with INCENP, CDCA8, and BIRC5 transcripts and accelerated INCENP mRNA decay. Functionally, INCENP depletion recapitulated the mitotic defects and impaired viability observed upon IGF2BP1 inhibition. Exploiting this mitotic vulnerability, BTYNB synergized with paclitaxel in CRC cell lines and across four independent IGF2BP1-positive patient-derived organoid models. Conclusions Our findings uncover an IGF2BP1-dependent post-transcriptional regulatory mechanism sustaining CPC expression and mitotic integrity in CRC. Targeting this mechanism exposes a therapeutically exploitable mitotic vulnerability and provides a rationale for combining IGF2BP1 inhibition with microtubule-targeting agents.

cancer biology↗

bioRxiv2026

Integrative enhancer discovery identifies functional enhancer dependencies in pediatric acute myeloid leukemia

Pediatric acute myeloid leukemia (AML) is driven by aberrant transcriptional programs sustained by poorly defined cis-regulatory mechanisms. To systematically identify functional enhancer dependencies, we developed an integrative enhancer discovery strategy that combines H3K27ac CUT&Tag profiling, enhancer-associated transcription, and CRISPR interference (CRISPRi) screening. By leveraging enhancer-associated transcription to prioritize candidate regulatory elements, we identified 321 leukemia-associated enhancers for functional interrogation. This approach uncovered the hematopoietic MYB enhancer (H-ME) within the HBS1L-MYB-AHI1 locus as a critical regulator of leukemic growth. H-ME repression reduced chromatin accessibility and active histone marks at the MYB promoter, suppressed MYB expression, and induced differentiation-associated transcriptional programs. In contrast, selective depletion of the enhancer-associated transcript had no effect on MYB expression or leukemic proliferation, demonstrating that enhancer activity resides within the underlying regulatory DNA element rather than its mature RNA product. H-ME exhibited preferential activity in megakaryocytic leukemia, and its perturbation impaired leukemic growth in primary patient-derived models in vitro and in vivo. Together, our findings establish an integrative framework for the systematic discovery of functional enhancer dependencies and identified H-ME as an RNA-independent regulator of MYB in pediatric AML.

cancer biology↗

bioRxiv2026

Lineage-restricted dependency on an oncofetal SNHG29-IGF2BP1 RNA axis in acute megakaryoblastic leukemia

Acute megakaryoblastic leukemia (AMKL) is a rare, aggressive subtype of acute myeloid leukemia with developmental origins in early childhood. To uncover long noncoding RNAs (lncRNAs) sustaining this high-risk malignancy, we conducted CRISPR interference screens targeting lncRNAs overexpressed in primary AMKL samples. This analysis identified SNHG29 as a previously unrecognized lineage-specific dependency, whose silencing profoundly impaired leukemic proliferation and clonogenic growth in vitro and reduced leukemic burden in vivo. RNA pulldown coupled with proteomic analysis revealed that SNHG29 interacts with the oncofetal RNA-binding protein IGF2BP1, which is aberrantly expressed in AMKL. SNHG29 was required to maintain expression of IGF2BP1 target transcripts, including MYC- and E2F-driven proliferative programs, thereby reinforcing fetal transcriptional programs essential for leukemic maintenance. Pharmacologic inhibition of IGF2BP1-RNA interactions with the small-molecule BTYNB induced potent and selective cytotoxicity in patient-derived AMKL models. Together, these findings uncover a developmental co-dependency between SNHG29 and IGF2BP1 that defines a lineage-restricted oncogenic circuit and an actionable therapeutic vulnerability in AMKL.

cancer biology↗

bioRxiv2024

A Genome-Wide Arrayed CRISPR Screen Reveals PLSCR1 as an Intrinsic Barrier to SARS-CoV-2 Entry

Interferons (IFNs) play a crucial role in the regulation and evolution of host-virus interactions. Here, we conducted a genome-wide arrayed CRISPR knockout screen in the presence and absence of IFN to identify human genes that influence SARS-CoV-2 infection. We then performed an integrated analysis of genes interacting with SARS-CoV-2, drawing from a selection of 67 large-scale studies, including our own. We identified 28 genes of high relevance in both human genetic studies of COVID-19 patients and functional genetic screens in cell culture, with many related to the IFN pathway. Among these was the IFN-stimulated gene PLSCR1. PLSCR1 did not require IFN induction to restrict SARS-CoV-2 and did not contribute to IFN signaling. Instead, PLSCR1 specifically restricted spike-mediated SARS-CoV-2 entry. The PLSCR1-mediated restriction was alleviated by TMPRSS2 over-expression, suggesting that PLSCR1 primarily restricts the endocytic entry route. In addition, recent SARS-CoV-2 variants have adapted to circumvent the PLSCR1 barrier via currently undetermined mechanisms. Finally, we investigate the functional effects of PLSCR1 variants present in humans and discuss an association between PLSCR1 and severe COVID-19 reported recently.

immunology↗

bioRxiv2021

Targeting the MYC interaction network in B-cell lymphoma via histone deacetylase 6 inhibition

Overexpression of MYC is a genuine cancer driver in lymphomas and related to poor prognosis. However, therapeutic targeting of the transcription factor MYC remains challenging. Here, we show that inhibition of the histone deacetylase 6 (HDAC6) using the HDAC6 inhibitor Marbostat-100 (M-100) reduces oncogenic MYC levels and prevents lymphomagenesis in a mouse model of MYC-induced aggressive B-cell lymphoma. M-100 specifically alters protein-protein interactions by switching the acetylation state of HDAC6 substrates, such as tubulin. Tubulin facilitates nuclear import of MYC, and MYC-dependent B-cell lymphoma cells rely on continuous import of MYC due to its high turn-over. Acetylation of tubulin impairs this mechanism and enables proteasomal degradation of MYC. M-100 targets almost exclusively B-cell lymphoma cells with high levels of MYC whereas non-tumor cells are not affected. M-100 induces massive apoptosis in human and murine MYC-overexpressing B-cell lymphoma cells. We identified the heat-shock protein DNAJA3 as an interactor of tubulin in an acetylation-dependent manner and overexpression of DNAJA3 resulted in a pronounced degradation of MYC. We propose a mechanism by which DNAJA3 associates with hyperacetylated tubulin in the cytoplasm to control MYC turnover. Taken together, our data demonstrate a beneficial role of HDAC6 inhibition in MYC-dependent B-cell lymphoma.

cancer biology↗

bioRxiv2021

Hepatocyte nuclear factor 4a and glucocorticoid receptor coordinately regulate lipid metabolism in mice fed a high-fat-high-sugar diet

Hepatocyte nuclear factor 4 (HNF4) and glucocorticoid receptor (GR), master regulators of liver metabolism, are down-regulated in fatty liver diseases. The present study was aimed to elucidate the role of down-regulation of HNF4 and GR in fatty liver and hyperlipidemia. Adult mice with liver-specific heterozygote and knockout (knockout) of HNF4 were fed a low-fat diet (LFD) or a high-fat-high-sugar diet (HFHS) for 15 days. Compared to LFD-fed mice, HFHS-fed wildtype mice had hepatic induction of lipid catabolic genes and down-regulation of lipogenic genes. Compared to HFHS-fed wildtype mice, HNF4 heterozygote mice had down-regulation of lipid catabolic genes, induction of lipogenic genes, and increased hepatic and blood levels of lipids, whereas HNF4 knockout mice had mild hypolipidemia, down-regulation of lipid-efflux genes, but induction of genes for uptake/storage of lipids. Sterol-regulatory-element-binding protein-1c (SREBP-1C), a master lipogenic regulator, was induced in HFHS-fed HNF4 heterozygote mice. In reporter assays, HNF4 potently inhibited the transactivation of mouse and human SREBP-1C promoter by liver X receptor. Surprisingly, nuclear GR proteins were gene-dosage-dependently decreased in HNF4 heterozygote and knockout mice. HFHS-fed mice with liver-specific knockout of GR had increased hepatic lipids and induction of SREBP-1C and PPAR{gamma}. In reporter assays, GR and HNF4 synergistically/additively induced lipid catabolic genes. Phosphorylation of AMP-activated protein kinase (AMPK), a key GR modulator, was dramatically decreased in HNF4 knockout mice. Thus, cooperative induction of lipid catabolic genes and suppression of lipogenic genes by HNF4 and GR, modulated by AMPK, may mediate the early resistance to HFHS-induced fatty liver and hyperlipidemia.

molecular biology↗

bioRxiv2020

SARS-CoV-2 utilizes a multipronged strategy to suppress host protein synthesis

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the ongoing coronavirus disease 19 (COVID-19) pandemic. Despite the urgent need, we still do not fully understand the molecular basis of SARS-CoV-2 pathogenesis and its ability to antagonize innate immune responses. Here, we use RNA-sequencing and ribosome profiling along SARS-CoV-2 infection and comprehensively define the mechanisms that are utilized by SARS-CoV-2 to shutoff cellular protein synthesis. We show SARS-CoV-2 infection leads to a global reduction in translation but that viral transcripts are not preferentially translated. Instead, we reveal that infection leads to accelerated degradation of cytosolic cellular mRNAs which facilitates viral takeover of the mRNA pool in infected cells. Moreover, we show that the translation of transcripts whose expression is induced in response to infection, including innate immune genes, is impaired, implying infection prevents newly transcribed cellular mRNAs from accessing the ribosomes. Overall, our results uncover the multipronged strategy employed by SARS-CoV-2 to commandeer the translation machinery and to suppress host defenses.

microbiology↗

bioRxiv2020

Target-Decoy MineR for determining the biological relevance of variables in noisy data sets

Machine learning algorithms excavate important variables from biological big data. However, deciding on the biological relevance of identified variables is challenging. The addition of artificial noise, decoy variables, to raw data, target variables, enables calculating a false-positive rate (FPR) and a biological relevance probability (BRp) for each variable rank. These scores allow the setting of a cut-off for informative variables can be defined, depending on the required sensitivity/ specificity of a scientific question. We demonstrate the function of the Target-Decoy MineR (TDM) with synthetic data and with experimental metabolomics results. The Target-Decoy MineR is suitable for different types of quantitative data in tabular format. An implementation of the algorithm in R is freely available from https://bitbucket.org/cesaremov/targetdecoy_mining/.

bioinformatics↗