Biology subjects

Demaria, M.

Publications and source records attributed to Demaria, M..

7 recordsLinked to original sources

bioRxiv2026

A two-step organoid screen identifies transient p53 activation as a senolytic strategy for radiation-induced salivary gland dysfunction

Radiotherapy significantly improves the survival of head and neck cancer patients. However, it frequently damages the salivary glands, causing persistent hyposalivation and xerostomia. Radiation-induced cellular senescence within the salivary gland stem/progenitor cell niche contributes to hyposalivation, suggesting that selective elimination of senescent cells could promote tissue recovery. However, the effectiveness of senolytic compounds is strongly context dependent, varying with tissue of origin and potentially impairing regenerative cells required for functional restoration. Here, we developed a two-step organoid-based screening methodology that integrates the preferential induction of apoptosis in irradiated, senescence enriched, salivary gland organoids with the preservation of stem/progenitor cell regenerative capacity. As a first step, the senolytic activity of candidate drugs was tested to identify drugs that induced apoptosis in senescent cells of irradiated organoids but were not or less toxic to unirradiated organoids. As a second step, the confirmed senolytic compounds were tested for effects on stem cell self-renewal potential. Using this approach, we identified Nutlin3a, an MDM2 inhibitor and p53 activator, as the compound with the most favorable toxicity profile in salivary glands. Last, we confirmed the anti-senescence and pro-regenerative potential of Nutlin3a in an in vivo mouse model of radiation-induced hyposalivation, where localized Nutlin3a delivery resulted in a robust increase in saliva production, as early as two weeks after administration. These findings establish an organoid-based strategy for identifying tissue-adapted senolytic interventions and propose transient local p53 activation with Nutlin3a as a potential approach to mitigate radiation-induced salivary gland dysfunction.

cell biology↗

bioRxiv2026

Targeting cellular senescence alleviates bone marrow aging

Aging of the hematopoietic system impairs hematopoietic stem cell (HSC) function and alters bone marrow niche behavior, increasing susceptibility to anemia, infections, and hematologic malignancies. Here, pharmacologic clearance of senescent cells with the PROTAC compound 753b simultaneously targeting BCL-xL and BCL-2 reverses key secretory, transcriptional, and functional hallmarks of hematopoietic aging with low toxicity, restoring balanced lineage output. Single-cell RNA sequencing further demonstrates that 753b treatment attenuates aging-associated transcriptional signatures in HSCs, while selectively eliminating senescent, pro-survival niche cells without grossly perturbing niche composition. Functionally, 753b suppresses pro-inflammatory cues from both niche and hematopoietic cells including those emanating from neutrophil progenitors, rebalancing global bone marrow secretory ecosystem across stromal and hematopoietic compartments. Collectively, we identify 753b-induced senescent cell clearance as a powerful strategy to rejuvenate aged hematopoiesis and re-establish homeostatic communication between HSCs and their microenvironment, with implications for mitigating age-related hematologic dysfunction and improving hematologic health in older individuals.

cell biology↗

bioRxiv2026

Reproducible in vivo applications of the p16-3MR model in senescence research

The p16-3MR mouse model has been widely used to visualize and conditionally eliminate p16-expressing senescent cells in vivo and has been applied across diverse biological contexts, including tissue repair, fibrosis, cancer, therapy response, and aging. Despite the development of multiple senescence reporter and ablation systems, p16-3MR stands out for its broad and sustained adoption across independent laboratories. Here, we review the extensive published literature supporting the reproducibility and utility of the p16-3MR system and present new validation data across acute and chronic senescence-inducing conditions. We demonstrate reproducible induction of p16-associated bioluminescence during wound healing, chemotherapy, and aging, as well as partial but consistent reduction following ganciclovir treatment. We further delineate the strengths and limitations of the individual components of the 3MR construct, including HSV-thymidine kinase-mediated clearance, Renilla luciferase- based bioluminescence, and monomeric red fluorescent protein, and discuss how factors such as cell abundance, tissue context, pigmentation, and substrate chemistry influence detection sensitivity. Together, these data confirm that the p16-3MR model is a functional and versatile tool for studying senescent cells in vivo when used with appropriate experimental design and interpretation, and they provide support for its continued application alongside emerging senescence models.

cell biology↗

bioRxiv2024

Transcriptional profiling reveals a previously unknown population of Cdkn2a-positive tumor-associated macrophages in aggressive brain cancer

Microglia, the resident immune cells of the Central Nervous System (CNS), play crucial roles in homeostasis, immune responses, and the modulation of neuronal functions. In brain tumors, microglia are difficult to distinguish from infiltrating macrophages and are collectively called Tumor-Associated Macrophages (TAMs). While these cells exhibit plasticity, support tumor growth, and suppress antitumor immune responses, their identity and function remain largely unknown. Cellular senescence, a state of growth arrest associated with the upregulation of the cell cycle inhibitor p16INK4A (Cdkn2a), can both suppress and promote tumor progression via the secretion of inflammatory and tissue remodeling factors, collectively known as Senescence-Associated Secretory Phenotype (SASP). By leveraging existing single-cell RNA sequencing (scRNA-seq) data of murine brain tumors, we identified a population of Cdkn2a-positive TAMs involved in immune regulation and neurogenesis, characterized by high expression of Emb and Cd93, which we named MECC (Microglia-like, and Emb-, CD93- and Cdkn2a-positive) cells. In humans, these cells were more prevalent in recurrent glioblastoma and associated with poorer prognosis. Comparative analysis of brain samples from patients with neurodegeneration and healthy older individuals revealed the specificity of MECCs for brain tumors. These findings suggest that MECCs are a unique and distinct cell population associated with aggressive brain tumors, which could potentially serve as targets for novel treatments.

cancer biology↗

bioRxiv2024

CDK4/6 inhibitors promote senescence-associated lysosomal alterations and enhance sensitivity to lysosomotropic agents in breast cancer

Breast cancer is a leading cause of mortality worldwide. Pharmacological inhibitors of Cyclin- Dependent Kinases (CDK) 4 and 6 (CDK4/6i) inhibit breast cancer growth by inducing a senescent-like state. However, the long-term treatment efficacy remains hindered by the development of drug resistance. Clearance of senescent-like cancer cells may extend the durability of treatment. In this study, we showed that CDK4/6i-treated breast cancer cells exhibit various senescence-associated phenotypes, but remain insensitive to common senolytic compounds. By searching for novel vulnerabilities, we identified a significantly increased lysosomal mass and altered lysosomal structure across various breast cancer cell types upon exposure to CDK4/6i in preclinical systems and clinical specimens. We demonstrated that these lysosomal alterations render breast cancer cells sensitive to lysosomotropic agents, such as L- leucyl-L-leucine methyl ester (LLOMe) and salinomycin. Importantly, sequential treatment with CDK4/6i/lysosomotropic agents effectively reduced the growth of both Hormone Receptor- positive (HR+) and triple-negative breast cancer (TNBC) cells in vivo. This sequential therapeutic strategy offers a promising approach to eliminate CDK4/6i-induced senescent(-like) cells, potentially reducing tumor recurrence and enhancing the overall efficacy of breast cancer therapy.

cancer biology↗

bioRxiv2020

Genomic instability is an early event driving chromatin reorganization and escape from oncogene-induced senescence

Oncogene-induced senescence (OIS) is an inherent and important tumor suppressor mechanism. However, if not timely removed via immune surveillance, senescent cells will also present a detrimental side. Although this has mostly been attributed to the senescence-associated-secretory-phenotype (SASP) of these cells, we recently proposed that "escape" from the senescent state represents another unfavorable outcome. Here, we exploit genomic and functional data from a prototypical human epithelial cell model carrying an inducible CDC6 oncogene to identify an early-acquired recurrent chromosomal inversion, which harbors a locus encoding the circadian transcription factor BHLHE40. This inversion alone suffices for BHLHE40 activation upon CDC6 induction and for driving cell cycle re-entry and malignant transformation. In summary, we now provide strong evidence in support of genomic instability underlying "escape" from oncogene-induced senescence. HIGHLIGHTSO_LIOncogene driven error-prone repair produces early genetic lesions allowing escape from senescence C_LIO_LICells escaping oncogene-induced senescence display mutational signatures observed in cancer patients C_LIO_LIA single recurrent inversion harboring a circadian TF gene suffices for bypassing oncogene-induced senescence C_LIO_LIChromatin loop and compartment remodeling support the "escape" transcriptional program C_LI

cell biology↗

bioRxiv2020

CDK4/6 inhibition promotes senescent states with restricted secretory phenotype and reduced toxicity

Cellular senescence is a state of stable growth arrest that acts as a tumor suppressive mechanism. Several anti-cancer interventions function partly by inducing malignant cells into senescence. However, because of systemic administration and lack of specificity, anti-cancer treatments are associated with premature senescence of various non-malignant cells. Therapy-induced non-malignant senescent cells can have profound detrimental pro-tumorigenic and pro-disease functions via activation of a pro-inflammatory and NF-{kappa}B-mediated secretory phenotype (SASP). Inhibitors of the cyclin-dependent kinases 4/6 (CDK4/6i) has recently shown to have potent cytostatic effects with reduced toxicities. Here, we show that CDK4/6i lead non-malignant cells to a senescent state that lacks the pro-inflammatory and NF-{kappa}B-associated SASP. Interestingly, CDK4/6i-induced senescence overexpressed a number of genes encoding for secreted proteins, which we show being dependent on p53 transcriptional activity. CDK4/6i-induced p16+ senescent cells with a p53-associated (PASP), but not NF-{kappa}B-associated (NASP), secretory phenotype do not exert detrimental and pro-tumorigenic functions, but still retain the capacity to induce paracrine senescence and undergo clearance in vivo. Our data suggest that that senescent cells with a PASP but without a NASP may be well-tolerated and may represent a less toxic outcome for cancer interventions.

cell biology↗