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Biology subjects

Fenou, L.

Publications and source records attributed to Fenou, L..

2 recordsLinked to original sources

Deciphering Oxygen Distribution and Hypoxia Profiles in the Tumor Microenvironment: A Data-Driven Mechanistic Modeling Approach

The distribution of hypoxia within tissues plays a critical role in tumor diagnosis and prognosis. Recognizing the significance of tumor oxygenation and hypoxia gradients, we introduce mathematical frameworks grounded in mechanistic modeling approaches for their quantitative assessment within a tumor microenvironment. Our approach provides a non-invasive method to measure and predict hypoxia using known blood vasculature. Formulating a reaction-diffusion model for oxygen distribution, we apply it to derive the corresponding hypoxia profile. The modeling and simulations successfully replicate the observed inter- and intra-tumor heterogeneity in experimentally obtained hypoxia profiles across various tumor tissues (breast, ovarian, and pancreatic) in our dataset. Employing a data-driven approach, we propose a method to deduce partial differential equation (PDE) models with spatially dependent parameters, enabling us to comprehend the variability of hypoxia profiles within a tissue. The versatility of our framework lies not only in capturing diverse and dynamic behaviors of tumor oxygenation but also in categorizing states of vascularization. These categories are distinguished based on the dynamics of oxygen molecules, as identified by the model parameters.

cancer biology↗

Replication poison treated BRCA1-deficient breast cancers are prone to MRE11 over-resection resulting in single strand DNA accumulation and mitotic catastrophe

BRCA1, BRCA2 and RAD51, key players of homologous recombination (HR) repair, are also involved in stalled DNA replication fork protection and repair. BRCA1-deficiency is encountered in 25% of Triple Negative Breast Cancer (TNBC). Here we investigated the sensitivity of BRCA1-deficient TNBC cell models to gemcitabine a frequently used replication poison that does not alter DNA structure. We show that BRCA1-deficient models, in contrast to their isogenic BRCA1-proficient counterparts, are superiorly sensitive to gemcitabine, accumulate massive levels of single strand DNA (ssDNA), in absence of RPA and RAD51 signals and elevated double strand break (DSB) numbers leading to cell death. Remarkably, ssDNA accumulation in gemcitabine-treated BRCA1-deficient cells was strongly diminished by the MRE11 inhibitor mirin, while it did not affect ssDNA levels resulting from PARP inhibitor olaparib treatment. The central role of MRE11 DNA resection strongly suggested that replication fork reversal may be important in response to replication poisoning by gemcitabine in BRCA1-deficient models. Furthermore, we demonstrate that gemcitabine-treated BRCA1-deficient cells showing massive ssDNA accumulation slipped into mitosis and produced mitotic bridges and micronuclei (MN) showing strong BrdU and {gamma}H2AX staining. Noticeably these BrdU-positive MN and DNA bridges triggered cGAS sensing. Our data, thus, strongly suggest that gemcitabine treatment could be beneficial in BRCA1-deficient TNBC both in terms of cancer cell death, but possibly as well in terms of antitumor immune response.

cancer biology↗