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Biology subjects

Salazar-Roa, M.

Publications and source records attributed to Salazar-Roa, M..

5 recordsLinked to original sources

CDC14 phosphatases control adipogenesis via PPARγ de-phosphorylation

Adipogenesis is a finely tuned process requiring an appropriate balance between proliferation and differentiation. We demonstrate that CDC14, a CDK-counteracting phosphatase, regulates adipogenesis and glucose metabolism in mammals. Simultaneous depletion of CDC14A and CDC14B protects against high-fat diet-induced obesity, hepatic steatosis and glucose intolerance in vivo. Lack of these phosphatases blocks differentiation of stem cells into adipocytes, a defect rescued by the PPAR{gamma} agonist troglitazone. Mechanistically, we show that CDC14 counteracts ERK2 and CDK5-induced phosphorylation of PPAR{gamma}, a master regulator of adipogenesis, by directly dephosphorylating S112, S273 and T296 residues. This study supports the idea that cell cycle regulators in multicellular organisms evolved to coordinate the balance between proliferation and differentiation in different cell types. Furthermore, since PPAR{gamma} is a key target of anti-diabetic drugs and a central regulator of adipogenesis and metabolism, these findings may have important implications for treatment of metabolic diseases such as type 2 diabetes.

cell biology↗

CB2R-induced differentiation epigenetically restrains cancer plasticity enabling adaptive therapy

Cellular plasticity enables cancer cells to escape therapy by adopting stem-like or alternate lineage states. Here, we identify a mechanism by which cannabinoid receptor 2 (CB2R) activation promotes irreversible lineage commitment in breast cancer. Using patient-derived and murine organoids, we show that brief, low-dose exposure to CB2R agonists--either phytogenic or synthetic--induces a basal-to-luminal transition, accompanied by reduced self-renewal, invasiveness, and tumor-initiating potential. These changes are retained under conditions that normally promote dedifferentiation, including fibroblast co-culture, immune pressure, and mechanical shear stress. Mechanistically, CB2R engagement initiates a transient chromatin remodeling program, marked by early expression of pluripotency-associated genes followed by silencing and differentiation commitment. This epigenetically stabilized state renders tumor cells more responsive to tamoxifen and limits the emergence of resistant clones. Our findings uncover a previously unrecognized role for CB2R in modulating cancer cell identity and suggest new opportunities to constrain tumor plasticity by directing differentiation through a drug-responsive pathway.

cancer biology↗

miR-203 drives breast cancer cell differentiation

A hallmark of many malignant tumors is dedifferentiated (immature) cells bearing slight or no resemblance to the normal cells from which the cancer originated. Tumor dedifferentiated cells exhibit a higher capacity to survive to chemo and radiotherapies and have the ability to incite tumor relapse. Inducing cancer cell differentiation would abolish their self-renewal and invasive capacity and could be combined with the current standard of care, especially in poorly differentiated and aggressive tumors (with worst prognosis). However, differentiation therapy is still in its early stages and the intrinsic complexity of solid tumor heterogeneity demands innovative approaches in order to be efficiently translated into the clinic. We demonstrate here that microRNA 203, a potent driver of differentiation in pluripotent stem cells (ESCs and iPSCs), promotes the differentiation of mammary gland tumor cells. Combining mouse in vivo approaches and both mouse and human-derived tridimensional organoid cultures, we report here that miR-203 influences the self-renewal capacity, plasticity and differentiation potential of breast cancer cells, and prevents tumor cell growth in vivo. Our work sheds light on differentiation-based antitumor therapies and offers miR-203 as a promising tool for directly confronting the tumor-maintaining and regeneration capability of cancer cells.

cancer biology↗

miR-203 imposes an intrinsic barrier during cellular reprogramming by targeting NFATC2

Cellular reprogramming from somatic to pluripotent cells is the basis for multiple applications aimed to replace damaged tissues in regenerative medicine. However, this process is limited by intrinsic barriers that are induced in response to reprogramming factors. In this manuscript we report that miR-203, a microRNA with multiple functions in differentiation and tumor suppression, acts as an endogenous barrier to reprogramming. Genetic ablation of miR-203 results in enhanced reprogramming whereas its expression prevents the formation of pluripotent cells both in vitro and in vivo. Mechanistically, this effect correlates with the direct repression of NFATC2, a transcription factor involved in the early phases of reprogramming. Inhibition of NFATC2 mimics miR-203 effects whereas NFATC2 overexpression rescues inducible cell pluripotency in miR-203-overexpressing cultures. These data suggest that miR-203 repression may favor the efficiency of reprogramming in a variety of cellular models.

cell biology↗

A novel microRNA-based strategy to expand the differentiation potency of stem cells

Full differentiation potential along with self-renewal capacity is a major property of pluripotent stem cells (PSCs). However, the differentiation capacity frequently decreases during expansion of PSCs in vitro. We show here that transient exposure to a single microRNA, expressed at early stages during normal development, improves the differentiation capacity of already-established murine and human PSCs. Short exposure to miR-203 in PSCs (miPSCs) results in expanded differentiation potency as well as improved efficiency in stringent assays such as tetraploid complementation and human-mouse interspecies chimerism. Mechanistically, these effects are mediated by direct repression of de novo DNA methyltransferases Dnmt3a and Dnmt3b, leading to transient and reversible erasing of DNA methylation. As a proof of concept, miR-203 improves differentiation and maturation of PSCs into cardiomyocytes in vitro as well as cardiac regeneration in vivo, after cardiac injury. These data support the use of transient exposure to miR-203 as a general and single method to reset the epigenetic memory in PSCs, and improve their use in regenerative medicine.

cell biology↗