Publications by authors named "Ana Fernandez-Ruiz"

5 Publications

  • Page 1 of 1

A hydride transfer complex reprograms NAD metabolism and bypasses senescence.

Mol Cell 2021 Sep;81(18):3848-3865.e19

CRCHUM, 900 Saint-Denis St, Montréal, QC H2X 0A9, Canada; Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3C 3J7, Canada. Electronic address:

Metabolic rewiring and redox balance play pivotal roles in cancer. Cellular senescence is a barrier for tumorigenesis circumvented in cancer cells by poorly understood mechanisms. We report a multi-enzymatic complex that reprograms NAD metabolism by transferring reducing equivalents from NADH to NADP. This hydride transfer complex (HTC) is assembled by malate dehydrogenase 1, malic enzyme 1, and cytosolic pyruvate carboxylase. HTC is found in phase-separated bodies in the cytosol of cancer or hypoxic cells and can be assembled in vitro with recombinant proteins. HTC is repressed in senescent cells but induced by p53 inactivation. HTC enzymes are highly expressed in mouse and human prostate cancer models, and their inactivation triggers senescence. Exogenous expression of HTC is sufficient to bypass senescence, rescue cells from complex I inhibitors, and cooperate with oncogenic RAS to transform primary cells. Altogether, we provide evidence for a new multi-enzymatic complex that reprograms metabolism and overcomes cellular senescence.
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http://dx.doi.org/10.1016/j.molcel.2021.08.028DOI Listing
September 2021

Oxidative stress-induced senescence mediates inflammatory and fibrotic phenotypes in fibroblasts from systemic sclerosis patients.

Rheumatology (Oxford) 2021 Jun 11. Epub 2021 Jun 11.

Faculty of Pharmacy, Université de Montréal, Québec, Canada.

Objective: Systemic sclerosis (SSc) is an autoimmune connective tissue disorder characterized by inflammation and fibrosis. Although constitutive activation of fibroblasts is proposed to be responsible for the fibrotic and inflammatory features of the disease, the underlying mechanism remains elusive and, effective therapeutic targets are still lacking. The aim of this study was to evaluate the role of oxidative stress-induced senescence and its contribution to the pro-fibrotic and pro-inflammatory phenotypes of fibroblasts from SSc patients.

Methods: Dermal fibroblasts were isolated from SSc (n = 13) and healthy (n = 10) donors. Fibroblast's intracellular and mitochondrial reactive oxygen species were determined by flow cytometry. Mitochondrial function measured by Seahorse XF24 analyzer. Fibrotic and inflammatory gene expressions were assessed by qPCR and key pro-inflammatory components of the fibroblasts' secretome (interleukin (IL) 6 and IL8) were quantified by ELISA.

Results: Compared to healthy fibroblasts, SSc fibroblasts displayed higher levels of both intracellular and mitochondrial ROS. Oxidative stress in SSc fibroblasts induced the expression of fibrotic genes and activated the transforming growth factor-β-activated kinase 1 (TAK1) -IκB kinase β (IKKβ)- interferon regulatory factor 5 (IRF5) inflammatory signaling cascade. These cellular responses paralleled the presence of a DNA damage response, a senescence-associated secretory phenotype and a fibrotic response. Treatment of SSc fibroblasts with ROS scavengers reduced their pro-inflammatory secretome production and fibrotic gene expression.

Conclusions: Oxidative stress-induced cellular senescence in SSc fibroblasts underlies their pro-inflammatory and pro-fibrotic phenotypes. Targeting redox imbalance of SSc fibroblasts enhances their in vitro functions and could be of relevance for SSc therapy.
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http://dx.doi.org/10.1093/rheumatology/keab477DOI Listing
June 2021

Phenylethynylbenzyl-modified biguanides inhibit pancreatic cancer tumor growth.

Sci Rep 2021 05 10;11(1):9854. Epub 2021 May 10.

Département de Chimie-Faculté des Arts et des Sciences, Université de Montréal, 2900 Edouard Montpetit, Succursale Centre-Ville, CP 6128, Montreal, QC, H3C3J7, Canada.

We present the design and synthesis of a small library of substituted biguanidium salts and their capacity to inhibit the growth of pancreatic cancer cells. We first present their in vitro and membrane activity, before we address their mechanism of action in living cells and in vivo activity. We show that phenylethynyl biguanidium salts possess higher ability to cross hydrophobic barriers, improve mitochondrial accumulation and anticancer activity. Mechanistically, the most active compound, 1b, like metformin, activated AMPK, decreased the NAD/NADH ratio and mitochondrial respiration, but at 800-fold lower concentration. In vivo studies show that compound 1b significantly inhibits the growth of pancreatic cancer xenografts in mice, while biguanides currently in clinical trials had little activity.
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http://dx.doi.org/10.1038/s41598-021-87993-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8110578PMC
May 2021

Ribosomal protein RPL22/eL22 regulates the cell cycle by acting as an inhibitor of the CDK4-cyclin D complex.

Cell Cycle 2019 Mar - Apr;18(6-7):759-770. Epub 2019 Mar 28.

a Department of Biochemistry and Molecular Medicine , Université de Montréal , Montréal , Québec , Canada.

Senescence is a tumor suppressor program characterized by a stable growth arrest while maintaining cell viability. Senescence-associated ribogenesis defects (SARD) have been shown to regulate senescence through the ability of the ribosomal protein S14 (RPS14 or uS11) to bind and inhibit the cyclin-dependent kinase 4 (CDK4). Here we report another ribosomal protein that binds and inhibits CDK4 in senescent cells: L22 (RPL22 or eL22). Enforcing the expression of RPL22/eL22 is sufficient to induce an RB and p53-dependent cellular senescent phenotype in human fibroblasts. Mechanistically, RPL22/eL22 can interact with and inhibit CDK4-Cyclin D1 to decrease RB phosphorylation both in vitro and in cells. Briefly, we show that ribosome-free RPL22/eL22 causes a cell cycle arrest which could be relevant during situations of nucleolar stress such as cellular senescence or the response to cancer chemotherapy.
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http://dx.doi.org/10.1080/15384101.2019.1593708DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6464582PMC
April 2020

The senescence-associated secretory phenotype and its regulation.

Cytokine 2019 05 16;117:15-22. Epub 2019 Feb 16.

Department of Biochemistry and Molecular Medicine, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec H3C 3J7, Canada; CRCHUM, 900 Saint-Denis - Room R10.432, Montréal, QC H2X 0A9, Canada. Electronic address:

The senescence-associated secretory phenotype (SASP) defines the ability of senescent cells to express and secrete a variety of extracellular modulators that includes cytokines, chemokines, proteases, growth factors and bioactive lipids. The role of the SASP depends on the context. The SASP reinforces the senescent cell cycle arrest, stimulates the immune-mediated clearance of potentially tumorigenic cells, limits fibrosis and promotes wound healing and tissue regeneration. On the other hand, the SASP can mediate chronic inflammation and stimulate the growth and survival of tumor cells. The regulation of the SASP occurs at multiple levels including chromatin remodelling, activation of specific transcription factors such as C/EBP and NF-κB, control of mRNA translation and intracellular trafficking. Several SASP modulators have already been identified setting the stage for future research on their clinical applications.
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http://dx.doi.org/10.1016/j.cyto.2019.01.013DOI Listing
May 2019
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