Biology subjects

Janiszewska, M.

Publications and source records attributed to Janiszewska, M..

8 recordsLinked to original sources

bioRxiv2026

Multi-region biopsies and patient-derived neurosphere cultures reveal spatial divergence in glioblastoma.

Intratumor heterogeneity (ITH) is one of the main reasons for the lack of effective targeted therapies for glioblastoma (GBM). Imaging-guided surgical navigation allows for tumor-wide sampling to account for variation across distant regions of the tumor, but typical drug screening is performed on cell lines derived from a single biopsy and does not account for GBM heterogeneity. Here we profiled matching MRI-guided multi-region primary tumor biopsies from 6 GBM cases (n=40 biopsies) and corresponding neurosphere cultures (n=30) derived from these spatially distinct tumor samples. We found that in vitro cultures derived from distinct regions of the same tumor display divergent phenotypes, proliferative capacity and ability to accumulate 5-aminolevulinic acid, used to visualize cancer cells during surgery. The differential drug response of the multi-region neurospheres remains linked to the gene expression of the original tumor biopsies. Thus, studies with multiregion-derived neurospheres are essential to faithfully model GBM ITH for therapeutic testing. KEY POINTSO_LIMulti-region biopsy-derived neurospheres represent distinct spatial locations in the GBM tumor. C_LIO_LICultures derived from different regions of the tumor retain phenotypic diversity. C_LIO_LIParental biopsy phenotype predicts drug response better than to in vitro phenotype. C_LI IMPORTANCE OF THE STUDYCell lines developed from spatially distinct regions of glioblastoma capture its intratumor heterogeneity. We show that while the transcriptional output of these cell lines is not connected to their spatial origin, their drug response can be linked to it. Thus, spatial heterogeneity reflected in our neurosphere collection provides a new paradigm for drug screening in these highly heterogenous and difficult to treat tumors.

cancer biology↗

bioRxiv2026

Selective Glucocorticoid Receptor Modulators of Immune Checkpoint Function

Glucocorticoids (GCs) coordinate immunity, inflammation, and metabolism through allosteric regulation of the glucocorticoid receptor (GR) transcription factor. GCs are indispensable anti-inflammatory drugs yet linking specific ligand-receptor structural states to specific biological outcomes has remained a major barrier to designing safer, more selective therapies. Using structure-based design, we developed selective glucocorticoid receptor modulators (SGRMs) of immune function by extending a steroidal scaffold from the ligand-binding pocket into an adjacent solvent channel. These SGRMs suppressed T cell pro-inflammatory cytokines and promoted differentiation of memory precursor T cells while showing minimal induction of M2 macrophage polarization or T cell checkpoint proteins PD-1 and CTLA-4, all key targets of immunotherapy. Molecular dynamics simulations revealed that solvent-channel substituents function as a lever arm to drive dynamic oscillations in the steroid core, thereby allosterically tuning GR activity states. Systematic perturbation of immune cells with a graded series of ligands enabled a ligand perturbation with machine learning (LPML) framework to map coregulated responses across cell types and identified effector T cell gene networks tightly coupled with immune checkpoint induction. This approach outlines a general strategy for decoding the logic of allosteric drug action, enabling the rational design of SGRMs with tailored immunomodulatory profiles.

systems biology↗

bioRxiv2025

Distribution and Shared Pathogenicity of Small-Spored Alternaria on Solanaceous Crops in Europe

Small-spored Alternaria species such as A. alternata and A. arborescens are frequently isolated from diseased potato and tomato plants. However, their respective host ranges and pathogenic behaviours remain poorly resolved, and it is unclear whether their occurrence across hosts reflects true specialisation or ecological opportunism. Limited genetic differentiation among these closely related taxa further complicates their classification as primary necrotrophs or secondary colonisers. In this study, we analysed natural populations of small-spored Alternaria from Germany, Poland, and Serbia using molecular phylogenetics, morphological characterisation, and controlled infection assays to clarify species identity, host associations, and pathogenic potential. Both A. alternata and A. arborescens were detected across all regions and hosts, indicating broad distribution and ecological overlap. The two species were consistently isolated from foliar lesions and were each capable of causing characteristic Alternaria Brown-Spot (ABS) symptoms, thereby fulfilling Kochs postulates. Phylogenetic analyses based on Alt A1 and RPB2 loci resolved two well-supported species clades and revealed extensive haplotype sharing across more than 1300 km, multiple hosts, and diverse climates, suggesting high gene flow and limited population structure. The consistent co-occurrence and comparable pathogenicity of A. alternata and A. arborescens underscore their equal ecological relevance and redefine their roles in ABS epidemiology. These findings indicate that perceived differences in host specialisation may be overstated and that both species contribute equally to Alternaria Brown-Spot epidemics in solanaceous crops.

microbiology↗

bioRxiv2025

Photoproximity labeling of c-Myc reveals SLK as a cancer specific co-regulator

Transcription factors (TFs) have long been aspirational therapeutic targets for the treatment of diseases, as their dysregulation is a common mechanism for altered cell states. Despite this, many TFs implicated in disease have disordered structures and lack canonical binding pockets, rendering them non-trivial targets for small molecule-based therapies. Directly inhibiting TF function has proven difficult, but indirect inhibition by targeting the effector molecules that modulate TF function is a promising, yet underexplored, alternative approach. Here we report a strategy for capturing cancer-specific protein-protein interactions using context-dependent {micro}Map photoproximity labeling. Using an intein-based method for catalyst conjugation in biochemically intact nuclei, we demonstrate that we can capture unique protein interactomes of c-Myc in healthy and cancerous prostate cell lines, and that these unique interactors can be mined to identify druggable vulnerabilities. We find that a cancer specific Myc interactor, SLK, selectively promotes c-Myc stabilization at the protein level, drives epithelial morphology, and is essential for tumorigenesis, validating it as a viable therapeutic target. Importantly, this stabilization is driven by a change in SLK splicing rather than expression at the protein or RNA levels. Furthermore, analysis of cancer patient data shows a strong correlation between this splice isoform and expression of c-Myc targets, suggesting this novel regulatory axis is operative across human cancer.

cancer biology↗

bioRxiv2024

Cell sorting based on single nucleotide variation enables characterization of mutation-dependent transcriptome and chromatin states.

Single nucleotide variants (SNVs) contribute to cancer by altering the coding and the non-coding regions of the genome. Connecting SNVs to transcriptomic and epigenetic changes at the single-cell level remains challenging. To enable studies of rare cell populations harboring specific point mutations, we developed STAR-FACS, Specific-To-Allele PCR-FACS, to sort cells based on genomic allele alterations. We show that STAR-FACS can separate cells based on TERT promoter mutation status and is compatible with bulk and single-cell transcriptomic and epigenetic profiling. We demonstrate that glioblastoma cell lines derived from the same tumor but harboring distinct TERT promoter SNVs have different transcriptional programs.

cancer biology↗

bioRxiv2024

Structural insights into IMP2 dimerization and RNA binding

IGF2BP2 (IMP2) is an RNA-binding protein that contributes to cancer tumorigenesis and metabolic disorders. Structural studies focused on individual IMP2 domains have provided important mechanistic insights into IMP2 function; however, structural information on full-length IMP2 is lacking but necessary to understand how to target IMP2 activity in drug discovery. In this study, we investigated the behavior of full-length IMP2 and the influence of RNA binding using biophysical and structural methods including mass photometry, hydrogen-deuterium exchange coupled to mass spectrometry (HDX-MS), and small angle x-ray scattering (SAXS). We found that full-length IMP2 forms multiple oligomeric states but predominantly adopts a dimeric conformation. Molecular models derived from SAXS data suggest the dimer is formed in a head-to-tail orientation by the KH34 and RRM1 domains. Upon RNA binding, IMP2 forms a pseudo-symmetric dimer different from its apo/RNA-free state, with the KH12 domains of each IMP2 molecule forming the dimer interface. We also found that the formation of IMP2 oligomeric species, which includes dimers and higher-order oligomers, is sensitive to ionic strength and RNA binding. Our findings provide the first insight into the structural properties of full-length IMP2, which may lead to novel opportunities for disrupting its function with more effective IMP2 inhibitors.

molecular biology↗

bioRxiv2022

Collateral lethality between HDAC1 and HDAC2 exploits cancer-specific NuRD complex vulnerabilities

Histone deacetylases (HDACs) have been widely pursued as targets for anti-cancer therapeutics. However, many of these targets are universally essential for cell survival, which may limit the therapeutic window that can be achieved by drug candidates. By examining large collections of CRISPR/Cas9-based essentiality screens, we discovered a genetic interaction between HDAC1 and HDAC2 wherein each paralog is synthetically lethal with hemizygous deletion of the other. This collateral synthetic lethality is caused by recurrent chromosomal translocations that occur in diverse solid and hematological malignancies, including neuroblastoma and multiple myeloma. Using genetic deletion or dTAG-mediated degradation, we show that HDAC2 disruption suppresses the growth of HDAC1-deficient neuroblastoma in vitro and in vivo. Mechanistically, we find that targeted degradation of HDAC2 in these cells prompts the degradation of several members of the nucleosome remodeling and deacetylase (NuRD) complex, leading to diminished chromatin accessibility at HDAC2/NuRD-bound sites of the genome and impaired control of enhancer-associated transcription. Furthermore, we reveal that several of the degraded NuRD complex subunits are dependencies in neuroblastoma and multiple myeloma, providing motivation to develop paralog-selective HDAC1 or HDAC2 degraders. Altogether, we identify HDAC1/2 collateral synthetic lethality as a new therapeutic target and reveal a novel mechanism for exploiting NuRD-associated cancer dependencies.

cancer biology↗

bioRxiv2021

Single-cell genetic heterogeneity linked to immune infiltration in glioblastoma.

Glioblastoma (GBM) is the most aggressive brain tumor with a median survival of ~15 months. Targeted approaches have not been successful in this tumor type due to the large extent of intratumor heterogeneity. Mosaic amplification of oncogenes suggests that multiple genetically distinct clones are present in each tumor. To uncover the relationships between genetically diverse subpopulations of GBM cells and their native tumor microenvironment, we employed highly multiplexed spatial protein profiling, coupled with single-cell spatial mapping of fluorescence in situ hybridization (FISH) for EGFR, CDK4, and PDGFRA. Single-cell FISH analysis of a total of 35,843 single nuclei (~2,100 per tumor) revealed that tumors in which amplifications of EGFR and CDK4 more frequently co-occur in the same cell exhibit higher infiltration of CD163+ immunosuppressive macrophages. Our results suggest that high throughput assessment of genomic alterations at the single cell level could provide a measure for predicting the immune state of GBM.

cancer biology↗