Biology subjects

Pouwels, J.

Publications and source records attributed to Pouwels, J..

5 recordsLinked to original sources

bioRxiv2025

Microtubule Inhibition Triggers MYC-Mediated Immunogenic Cell Death in Breast Cancer

Oncogenic MYC promotes cancer cell proliferation, metabolism, and death, while also driving immunosuppression in the tumour microenvironment, complicating immune-based therapies. To counter MYC-driven immune evasion while leveraging MYC-dependent synthetic lethality (MYC-SL), we identified microtubule-targeting agents, including eribulin, as potent inducers of immunogenic cell death in MYChigh triple-negative breast cancer (TNBC). A screen of 528 oncology compounds using damage-associated molecular pattern (DAMP) reporters revealed that microtubule inhibitors induced key DAMPs, including HMGB1 secretion, calreticulin exposure, and double-stranded DNA release, leading to gasdermin-E associated cell death in MYChigh TNBCs. Immune cell co-culture assays showed immune activation, and patient-derived explant cultures confirmed pro-inflammatory cytokine responses. In vivo, cell-free media from eribulin-treated MYChigh murine TNBCs enhanced tumour protection in vaccination models compared to MYC-knockdown controls, linking MYC-dependent DAMP release to immunogenicity. These findings highlight a dual-function therapeutic strategy: agents that selectively induce MYC-dependent immunogenic cell death can provide both targeted cytotoxicity and local immune stimulation, thereby addressing a key limitation of conventional chemotherapeutics, offering a new approach for MYC-driven cancers.

cancer biology↗

bioRxiv2024

Patient-derived tumor explant models of tumor immune microenvironment reveal distinct and reproducible immunotherapy responses

Tumor-resident immune cells play a crucial role in eliciting anti-tumor immunity and immunomodulatory drug responses, yet these functions have been difficult to study without tractable models of tumor immune microenvironment (TIME). Patient-derived ex vivo models contain authentic resident immune cells and therefore, could provide new mechanistic insights into how TIME responds to tumor or immune cell-directed therapies. Here, we assessed the reproducibility and robustness of immunomodulatory drug responses across two different ex vivo models of breast cancer TIME and one of renal cell carcinoma. These independently developed TIME models were treated with a panel of clinically relevant immunomodulators, revealing remarkably similar changes in gene expression and cytokine profiles among the three models in response to T cell activation and STING-agonism while still preserving individual patient-specific response patterns. Moreover, we found two common core signatures of adaptive or innate immune responses present across all three models and both types of cancer, potentially serving as a benchmark for drug-induced immune activation in ex vivo models of TIME. The robust reproducibility of immunomodulatory drug responses observed across diverse ex vivo models of TIME underscores the significance of human patient-derived models in elucidating the complexities of antitumor immunity and therapeutic interventions.

immunology↗

bioRxiv2023

Respiratory Complex I Regulates Dendritic Cell Maturation in Explant Model of Human Tumor Immune Microenvironment

Combining cytotoxic chemotherapy or novel anticancer drugs with T-cell modulators holds great promise in treating advanced cancers. However, the response varies depending on the tumor immune microenvironment (TIME). Therefore, there is a clear need for pharmacologically tractable models of the TIME to dissect its influence on mono- and combination treatment response at the individual level. Here we establish a Patient-Derived Explant Culture (PDEC) model of breast cancer, which retains the immune contexture of the primary tumor, recapitulating cytokine profiles and CD8+ T cell cytotoxic activity. We explored the immunomodulatory action of a synthetic lethal BCL2 inhibitor venetoclax + metformin drug combination ex vivo, discovering metformin cannot overcome the lymphocyte-depleting action of venetoclax. Instead, metformin promotes dendritic cell maturation through inhibition of mitochondrial complex I, increasing their capacity to co-stimulate CD4+ T cells and thus facilitating anti-tumor immunity. Our results establish PDECs as a feasible model to identify immunomodulatory functions of anticancer drugs in the context of patient-specific TIME.

cancer biology↗

bioRxiv2022

SHARPIN serine 146 phosphorylation mediates ARP2/3 interaction, cancer cell invasion, and metastasis

The adaptor protein SHARPIN is involved in a number of cellular processes and promotes cancer progression and metastasis. However, how the choice between different functions of SHARPIN is post-translationally regulated is unclear. Here we have characterized SHARPIN phosphorylation by mass spectrometry and in vitro kinase assay. Focusing on two uncharacterized phosphorylation sites, serine 131 and 146, in the unstructured linker region of SHARPIN, we demonstrate their role in SHARPIN-ARP2/3 complex interaction, whereas they play no role in integrin inhibition or LUBAC activation. Consistent with its novel role in ARP2/3 regulation, serine 146 (S146) phosphorylation of SHARPIN promoted lamellopodia formation. Notably, CRISPR-Cas9 mediated knockout of SHARPIN abrogated three-dimensional (3D) invasion of several cancer cell lines. The 3D invasion of cancer cells was rescued by overexpression of the wild-type SHARPIN, but not by SHARPIN S146A mutant, identifying S146 as an invasion promoting phosphorylation switch. Finally, we demonstrate that inhibition of phosphorylation at S146 significantly reduces the in vivo metastasis in the zebrafish model. Collectively, these results demonstrate that SHARPIN S146 phosphorylation constitutes a single functional determinant of cancer cell invasion both in vitro and in vivo.

cancer biology↗

bioRxiv2021

Ovarian cancers with low CIP2A tumor expression constitute an APR-246 sensitive disease subtype

Identification of ovarian cancer (OvCa) patient subpopulations with increased sensitivity to targeted therapies could offer significant clinical benefit. We report that 22% of the high grade OvCa tumors at diagnosis express CIP2A oncoprotein at low levels. CIP2Alow OvCa tumors have significantly lower likelihood of disease relapse after standard chemotherapy, but yet a portion of relapsed tumors retain their CIP2Alow phenotype. We further discover that reactive oxygen species (ROS) inducing compound APR-246 (PRIMA-1Met/Eprenetapopt), currently in clinical development, preferentially kill CIP2Alow OvCa cells across multiple chemotherapy resistant cell lines. Consistent with CIP2Alow OvCa subtype in humans, CIP2A is dispensable for development of MISIIR-TAg-driven mouse OvCa tumors. Nevertheless, CIP2A deficient OvCa tumor cells from MISIIR-TAg mice displayed APR-246 hypersensitivity both in vitro and in vivo. Mechanistically, the lack of CIP2A expression hypersensitizes the OvCa cells to APR-246 by inhibition of NF-kB activity. Accordingly, combination of APR-246 and Nf-kB inhibitor compounds strongly synergized in killing of CIP2A positive OvCa cells. Collectively, we discover low CIP2A expression as a vulnerability for APR-246 in OvCa. The results warrant consideration of clinical testing of APR-246 for CIP2Alow OvCa tumor subtype patients, and reveal CIP2A as a candidate APR-246 combination therapy target.

cancer biology↗