Biology subjects

Reilly, K.

Publications and source records attributed to Reilly, K..

6 recordsLinked to original sources

bioRxiv2026

Systematic mapping of chromatin dysregulation driven by viral transcriptional regulators at scale

Viral transcriptional regulators (vTRs) reprogram host cell transcriptional and epigenetic networks to promote infection, persistence, and oncogenic transformation. Despite their broad essentiality to viral pathogenesis, thousands of putative vTRs remain functionally uncharacterized. Here we apply PROD-ATAC, a pooled single-cell epigenomic screening platform, to map chromatin accessibility dysregulation induced by over 100 vTRs in a single assay. Our screen identified dozens of vTRs which directly and indirectly remodel chromatin, including variants with no previously reported epigenetic activity. Comparative analyses revealed that unrelated vTRs frequently opened chromatin regions associated with the same host transcription factor networks, including the NF-{kappa}B, AP-1, p53, and Sp1/KLF families. Integration of chromatin accessibility and transcriptomic datasets highlighted that epigenetic perturbations often coincide with downstream gene expression changes. By adapting PROD-ATAC to incorporate small-molecule perturbations, we demonstrate that targeted inhibition of host features (including the MAPK signaling cascade) can illuminate host dependencies for vTR-induced epigenomic dysregulation. These results establish a scalable framework for discovering virus-host chromatin interactions and suggest that epigenetic manipulation of host regulatory networks is a widespread and conserved function of many diverse vTRs.

genomics↗

bioRxiv2024

Identification of DLK1, a Notch ligand, as an immunotherapeutic target and regulator of tumor cell plasticity and chemoresistance in adrenocortical carcinoma

Immunotherapeutic targeting of cell surface proteins is an increasingly effective cancer therapy. However, given the limited number of current targets, the identification of new surface proteins, particularly those with biological importance, is critical. Here, we uncover delta-like non-canonical Notch ligand 1 (DLK1) as a cell surface protein with limited normal tissue expression and high expression in multiple refractory adult metastatic cancers including small cell lung cancer (SCLC) and adrenocortical carcinoma (ACC), a rare cancer with few effective therapies. In ACC, ADCT-701, a DLK1 targeting antibody-drug conjugate (ADC), shows potent in vitro activity among established cell lines and a new cohort of patient-derived organoids as well as robust in vivo anti-tumor responses in cell line-derived and patient-derived xenografts. However, ADCT-701 efficacy is overall limited in ACC due to high expression and activity of the drug efflux protein ABCB1 (MDR1, P-glycoprotein). In contrast, ADCT-701 is extremely potent and induces complete responses in DLK1+ ACC and SCLC in vivo models with low or no ABCB1 expression. Genetic deletion of DLK1 in ACC dramatically downregulates ABCB1 and increases ADC payload and chemotherapy sensitivity through NOTCH1-mediated adrenocortical de-differentiation. Single cell RNA-seq of ACC metastatic tumors reveals significantly decreased adrenocortical differentiation in DLK low or negative cells compared to DLK1 positive cells. This works identifies DLK1 as a novel immunotherapeutic target that regulates tumor cell plasticity and chemoresistance in ACC. Our data support targeting DLK1 with an ADC in ACC and neuroendocrine neoplasms in an active first-in-human phase I clinical trial (NCT06041516).

cancer biology↗

bioRxiv2024

Enhancing oncolytic virotherapy by exosome-mediated microRNA reprograming of the tumour microenvironment.

BackgroundThere has been limited success of cancer immunotherapies in the treatment of ovarian cancer (OvCa) to date, largely due to the immunosuppressive tumour microenvironment (TME). Tumour-associated macrophages (TAMs) are a major component of both the primary tumour and malignant ascites, promoting tumour growth, angiogenesis, metastasis, chemotherapy resistance and immunosuppression. Differential microRNA (miRNA) profiles have been implicated in the plasticity of TAMs. Therefore, delivering miRNA to TAMs to promote an anti-tumour phenotype is a novel approach to reverse their pro-tumour activity and enhance the efficacy of cancer immunotherapies. Oncolytic viruses (OVs) preferentially replicate in tumour cells making them ideal vehicles to deliver miRNA mimetics to the TME. Importantly, miRNA expressed by OVs get packaged within tumour-derived extracellular vesicles (TDEVs), and release of TDEV is augmented by OV infection, thus enhancing the dissemination of miRNA throughout the TME. MethodSmall RNAseq was used to identify differentially expressed miRNA during TAM generation and following LPS/IFN{gamma} stimulation to induce an anti-tumour phenotype. Two differentially expressed miRNA identified, miR-155 and miR-19a, were cloned into oncolytic rhabdovirus (ORV), and anti-tumour efficacy was investigated using both in vitro and in vivo models of OvCa. ResultsThis study demonstrates that ORV infection enhances TDEV production in OvCa cell lines both in vitro and in vivo and that TDEV are preferentially taken up by myeloid cells, including TAMs. Small RNAseq identified 23 miRNAs that were significantly upregulated in anti-tumour TAMs, including miR-155-5p. While 101 miRNAs were downregulated during pro-tumour TAM differentiation, including miR-19a-3p. Culturing TDEV expressing miR-155 or miR-19a with TAMs reversed their immunosuppressive activity, as measured by T cell proliferation. While ORV-miR-155 enhanced the generation of anti-tumour T cells, only ORV-miR19a significantly improved survival of mice bearing ovarian tumours. ConclusionThis study demonstrates (i) that arming ORVs with immunomodulatory miRNA is an effective approach to deliver miRNA to myeloid cells within the TME and (ii) that miRNA have the capacity to reverse the tumour promoting properties of TAMs and improve the efficacy of cancer immunotherapies, such as OV.

cancer biology↗

bioRxiv2023

Self-renewing Sox9+ osteochondral stem cells in the postnatal skeleton

Postnatal skeletal growth, homeostatic maintenance, and regeneration is driven by skeletal stem cells. In addition, it is well established that skeletal tissues lose their regenerative potential with age, comorbidities, and repeated trauma, possibly through stem cell exhaustion or loss of function. However, it is largely unknown where these cells reside in skeletal tissues, what molecular mechanisms regulate their self-renewal and fate decisions, and how to isolate, purify, and expand them ex vivo. Therefore, there is an urgent need for a deeper understanding of postnatal skeletal stem cells. Here, we used genetic lineage tracing, thymidine analogues retention, whole bone microscopy, imaging cytometry, in vitro assays, and single cell transcriptomics and provide the first experimental evidence for the existence of self-renewing osteochondral stem cells in the postnatal skeleton in both males and females. We also show direct comparisons between adult, fetal, mouse, and human skeletal stem cells at the transcriptome level.

developmental biology↗

bioRxiv2022

Therapeutic vulnerability to ATR inhibition in concurrent NF1 and ATRX-deficient high-grade solid tumors

Subsets of Neurofibromatosis Type 1 (NF1)-associated solid tumors have been shown to display high frequencies of ATRX mutations and presence of alternative lengthening of telomeres (ALT). In addition, a potential biologic vulnerability of ALT-positive cancer cells is ATR inhibition, a regulator of homologous recombination. We studied the phenotype of combined NF1 and ATRX deficiency in malignant solid tumors. For these experiments, cell lines derived from NF1-deficient sporadic glioblastomas (U251, SF188), a NF1-associated ATRX mutant glioblastoma cell line (JHH-NF1-GBM1), a NF1-derived sarcoma cell line (JHH-CRC65), and two NF1-deficient MPNST cell lines (ST88-14, NF90.8) were utilized. Cancer cells were treated with ATR inhibitors (AZD6738 and VE-822), in vitro, with or without a MEK inhibitor (AZD6244, selumetinib) or temozolomide. In contrast to the glioma cell line SF188, combined ATRX knockout (KO) and TERC KO led to ALT-like properties and sensitized U251 glioma cells to ATR inhibition (AZD6738 and VE-822) in vitro and in vivo. In addition, ATR inhibitors sensitized U251 cells to temozolomide, but not MEK inhibition (AZD6244), irrespective of ATRX level manipulation; whereas, the JHH-NF1-GBM1 cell line (ATRX loss/ALT-positive) demonstrated sensitivity to ATR inhibition (AZD6738), but not temozolomide. Similar effects were noted using the MPNST cell line NF90.8 after combined ATRX knockdown and TERC KO; however, not in the MPNST cell line ST88-14. Taken together, our study supports the feasibility of targeting the ATR pathway in subsets of NF1-deficient and associated tumors. Tumors with pre-existing ALT, or that subsequently develop ALT after ATRX downregulation, are particularly vulnerable to this therapeutic approach.

cancer biology↗

bioRxiv2019

Expression profiling of single cells and patient cohorts identifies multiple immunosuppressive pathways and an altered natural killer cell phenotype in glioblastoma

Glioblastoma (GBM) is an aggressive cancer with a very poor prognosis. Generally viewed as weakly immunogenic, GBM responds poorly to current immunotherapies. To better understand this problem we used a combination of NK cell functional assays together with gene and protein expression profiling to define the NK cell response to GBM and explore immunosuppression in the GBM microenvironment. In addition, we used transcriptome data from patient cohorts to classify GBM according to immunological profiles. We show that glioma stem-like cells, a source of post-treatment tumour recurrence, express multiple immunomodulatory cell surface molecules and are targeted in preference to normal neural progenitor cells by natural killer (NK) cells ex vivo. In contrast, GBM-infiltrating NK cells express reduced levels of activation receptors within the tumour microenvironment, with hallmarks of TGF-{beta} mediated inhibition. This NK cell inhibition is accompanied by expression of mutiple immune checkpoint molecules on T cells. Single cell transcriptomics demonstrated that both tumour and haematopoietic-derived cells in GBM express multiple, diverse mediators of immune evasion. Despite this, immunome analysis across a patient cohort identifies a spectrum of immunological activity in GBM, with active immunity marked by co-expression of immune effector molecules and feedback inhibitory mechanisms. Our data show that GBM is recognised by the immune system but that anti-tumour immunity is restrained by multiple immunosuppressive pathways, some of which operate in the healthy brain. The presence of immune activity in a subset of patients suggests that these patients will more likely benefit from combination immunotherapies directed against multiple immunosuppressive pathways.

immunology↗