Biology subjects

Klefstrom, J.

Publications and source records attributed to Klefstrom, J..

6 recordsLinked to original sources

bioRxiv2026

MYC Overexpression Confers Sensitivity to TACC3 Inhibition for Triple-Negative Breast Cancer

The oncogenic transcription factor MYC is overexpressed across many cancer types, including triple-negative breast cancers (TNBCs), where it drives cell proliferation, chromosomal instability, and immune suppression. As MYC has proven difficult to target directly, identifying vulnerabilities created by MYC-driven mitotic rewiring is of significant therapeutic interest. Using a focused pharmacological screen of mitosis-related targets that are overexpressed in the context of MYC signaling, we identified several previously unrecognized dependencies on mitotic spindle proteins, including KIF18A and TACC3 in MYCHIGH cells. We focused on TACC3 and found the small molecule inhibitor BO-264 induced pronounced micronuclei formation, cell cycle arrest, transcriptional reactivation of inflammatory signaling, and heightened cytotoxicity in MYCHIGH models. TACC3 inhibition activates interferon-stimulated response element (ISRE) mediated inflammatory signaling and can activate the cGAS-STING pathway in a subset of triple-negative breast cancer contexts. Together, these findings identify TACC3 as a MYC-driven mitotic vulnerability. We highlight TACC3 inhibition as a promising strategy to impair tumor cell fitness and activate tumor-intrinsic inflammatory responses in MYC-driven cancers.

cancer biology↗

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↗

bioRxiv2025

Complex I Drives Glutamine-Dependent TCA Cycle to Support Viability of MYChigh Breast Cancer Cells

In many cancers, stably elevated MYC levels drive persistent and concerted activation of cell growth promoting anabolic programs and the cell cycle in ways that are distinct from normal cells. Therefore, synthetic-lethal strategies to target MYC reprograming of these pathways may identify new selective anticancer therapies for the treatment of MYChigh tumors. Here, we identify enhanced mitochondrial respiration as a hallmark of MYC overexpressing cancer cells. Mitochondrial respiration sustains the TCA cycle by regenerating NAD+ through complex I-mediated oxidation of NADH. Metabolic carbon tracing analysis revealed that MYC shifts TCA cycles carbon source from glucose to glutamine. Inhibition of the glutamine-fueled TCA cycle using NAD+-depleting complex I inhibitors resulted in MYC-dependent synthetic lethality in breast cancer cells. In mouse models of MYChigh tumors, persistent inhibition of tumor growth was achieved through combined inhibition of complex I and glutaminolysis. Our results suggest that the high respiration rate observed in MYChigh cells supports glutamine carbon-enriched TCA cycle, rendering MYChigh tumors selectively vulnerable to inhibitors of mitochondrial respiration and glutaminolysis.

cancer biology↗

bioRxiv2024

Biomimetic porous silicon for rationally engineered combination therapy to induce immunogenic cell death

Combined chemo-photothermal therapy (CHT-PTT) is a promising treatment for metastatic cancers. It enables the synergistic induction of immunogenic cell death (ICD), while sensitising suppressive tumour microenvironment to immunotherapy. To induce ICD, the rational design of a combined CHT-PTT regimen remains unclear. In the present study, black porous silicon nanoparticles (BPSi NPs) were utilized as both drug carriers and photothermal conversion agents. To enhance their colloidal stability and homotypic targeting, BPSi NP surfaces were modified with polyethylene glycol and further coated with cancer cell membranes (CMs). Six chemotherapeutic drugs with different cell growth inhibition mechanisms were tested against metastatic MDA-MB-231 breast cancer cells to evaluate their ICD induction potentials. Finally, in the combined CHT-PTT, the effect of temperature was evaluated. Based on the analysis of ICD markers, high-mobility group box 1 and calreticulin proteins, we found that bromodomain-containing protein 4 inhibitor, (+)-JQ-1 (JQ1) was the optimal drug, and the mild-hyperthermia temperature of 45 {degrees}C was the best temperature setting in the combined CHT-PTT to induce ICD. Thus, our study provides rationally designed CHT-PTT regimen for efficient cancer treatment with high efficacy and low side effects.

bioengineering↗

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↗

bioRxiv2019

Laminin alpha 5 is Necessary for Mammary Epithelial Growth and Function by Maintaining Luminal Epithelial Cell Identity

Epithelial attachment to the basement membrane (BM) is essential for mammary gland development, yet the exact roles of specific BM components remain unclear. Here, we demonstrate that expression of distinct laminin -isoforms by luminal and basal mammary epithelial cells enforces lineage identity that is necessary for normal mammary gland growth and function. Laminin 5 (LM5) is mainly expressed by the luminal epithelial cells, and it is necessary for pubertal mammary gland growth, pregnancy induced gland remodeling, and for alveolar function. Adhesion to LM5 containing laminin promotes luminal traits in both luminal and basal epithelial cells, and reduces progenitor activity of basal epithelial cells. Mechanistically, we show that Lama5 loss interferes with differentiation of hormone receptor positive luminal cells, which results in reduced Wnt4 expression and defective crosstalk between luminal and basal epithelial cells during gland remodeling. Our results reveal a novel BM-mediated mechanism, which regulates mammary gland remodeling and function via specification of luminal epithelial cells.

cell biology↗