Browsing by Author "Retamal, Claudio"
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- ItemAnti-Ribosomal P Protein Autoantibodies From Patients With Neuropsychiatric Lupus Impair Memory in Mice(2015) Bravo Zehnder, Marcela; Toledo, Enrique M.; Segovia Miranda, Fabian; Serrano, Felipe G.; Benito, Maria J.; Metz Baer, Claudia Andrea; Retamal, Claudio; Álvarez Rojas, Alejandra; Massardo Vega, Loreto; Inestrosa Cantín, Nibaldo
- ItemD-Propranolol Impairs EGFR Trafficking and Destabilizes Mutant p53 Counteracting AKT Signaling and Tumor Malignancy(2021) Barra, Jonathan; Cerda-Infante, Javier; Sandoval, Lisette; Gajardo-Meneses, Patricia; Henriquez, Jenny F.; Labarca, Mariana; Metz, Claudia; Venegas, Jaime; Retamal, Claudio; Oyanadel, Claudia; Cancino, Jorge; Soza, Andrea; Cuello, Mauricio A.; Carlos Roa, Juan; Montecinos, Viviana P.; Gonzalez, AlfonsoSimple Summary Cancer progression is frequently driven by altered functions of EGFR belonging to the tyrosine-kinase family of growth factor receptors and by the transcription factor p53, which is called the "genome guardian". We report that D-Propranolol, previously used for other purposes in human patients, has antitumor effects involving a redistribution of cell surface EGFR to intracellular compartments and degradation of gain-of-function mutants of p53 (GOF-mutp53). These effects can be seen in cancer cell lines expressing EGFR and GOF-mutp53 and are reproduced in vivo, reducing tumor growth and prolonging survival of xenografted mice. D-Propranolol is proposed as a prototype drug for a new strategy against highly aggressive EGFR- and mutp53-expressing tumors. Cancer therapy may be improved by the simultaneous interference of two or more oncogenic pathways contributing to tumor progression and aggressiveness, such as EGFR and p53. Tumor cells expressing gain-of-function (GOF) mutants of p53 (mutp53) are usually resistant to EGFR inhibitors and display invasive migration and AKT-mediated survival associated with enhanced EGFR recycling. D-Propranolol (D-Prop), the non-beta blocker enantiomer of propranolol, was previously shown to induce EGFR internalization through a PKA inhibitory pathway that blocks the recycling of the receptor. Here, we first show that D-Prop decreases the levels of EGFR at the surface of GOF mutp53 cells, relocating the receptor towards recycling endosomes, both in the absence of ligand and during stimulation with high concentrations of EGF or TGF-alpha. D-Prop also inactivates AKT signaling and reduces the invasive migration and viability of these mutp53 cells. Unexpectedly, mutp53 protein, which is stabilized by interaction with the chaperone HSP90 and mediates cell oncogenic addiction, becomes destabilized after D-Prop treatment. HSP90 phosphorylation by PKA and its interaction with mutp53 are decreased by D-Prop, releasing mutp53 towards proteasomal degradation. Furthermore, a single daily dose of D-Prop reproduces most of these effects in xenografts of aggressive gallbladder cancerous G-415 cells expressing GOF R282W mutp53, resulting in reduced tumor growth and extended mice survival. D-Prop then emerges as an old drug endowed with a novel therapeutic potential against EGFR- and mutp53-driven tumor traits that are common to a large variety of cancers.
- ItemEpidermal growth factor receptor endocytic traffic perturbation by phosphatidate phosphohydrolase inhibition : new strategy against cancer(2014) Shaughnessy, Ronan Patrick; Retamal, Claudio; Oyanadel, Claudia; Norambuena Pérez, Andrés; López, Alejandro; Bravo Zehnder, Marcela; Montecino, Fabián, J.; Metz Baer, Claudia Andrea; Soza Gajardo, Andrea; González de la Rosa, Alfonso
- ItemFact or Fiction, It Is Time for a Verdict on Vasculogenic Mimicry?(2019) Valdivia Román, Andrés Felipe; Mingo Orsini, Gabriel Antonio; Aldana, Varina; Pinto, Mauricio P.; Ramírez, Marco; Retamal, Claudio; González, Alfonso; Nualart, Francisco; Corválan, Alejandro H.; Owen, Gareth Ivor
- ItemGalectin-8 induces partial epithelial-mesenchymal transition with invasive tumorigenic capabilities involving a FAK/EGFR/proteasome pathway in Madin-Darby canine kidney cells(2018) Oyanadel, Claudia; Holmes, Christopher; Pardo, Evelyn; Retamal, Claudio; Shaughnessy, Ronan; Smith, Patricio; Cortes, Priscilla; Bravo-Zehnder, Marcela; Metz, Claudia; Feuerhake, Teo; Romero, Diego, V; Carlos Roa, Juan; Montecinos, Viviana; Soza, Andrea; Gonzalez, AlfonsoEpithelial cells can acquire invasive and tumorigenic capabilities through epithelial-mesenchymal- transition (EMT). The glycan-binding protein galectin-8 (Gal-8) activates selective beta 1-integrins involved in EMT and is overexpressed by certain carcinomas. Here we show that Gal-8 overexpression or exogenous addition promotes proliferation, migration, and invasion in nontumoral Madin-Darby canine kidney (MDCK) cells, involving focal-adhesion kinase (FAK)-mediated transactivation of the epidermal growth factor receptor (EGFR), likely triggered by alpha 5 beta 1 integrin binding. Under subconfluent conditions, Gal-8-overexpressing MDCK cells (MDCK-Gal-8(H)) display hallmarks of EMT, including decreased E-cadherin and up-regulated expression of vimentin, fibronectin, and Snail, as well as increased beta-catenin activity. Changes related to migration/invasion included higher expression of alpha 5 beta 1 integrin, extracellular matrix-degrading MMP13 and urokinase plasminogen activator/urokinase plasminogen activator receptor (uPA/uPAR) protease systems. Gal-8-stimulated FAK/EGFR pathway leads to proteasome overactivity characteristic of cancer cells. Yet MDCK-Gal-8H cells still develop apical/basolateral polarity reverting EMT markers and proteasome activity under confluence. This is due to the opposite segregation of Gal-8 secretion (apical) and beta 1-integrins distribution (basolateral). Strikingly, MDCK-Gal-8(H) cells acquired tumorigenic potential, as reflected in anchorage-independent growth in soft agar and tumor generation in immunodeficient NSG mice. Therefore, Gal-8 can promote oncogenic-like transformation of epithelial cells through partial and reversible EMT, accompanied by higher proliferation, migration/invasion, and tumorigenic properties.
- ItemNegative Modulation of Macroautophagy by Stabilized HERPUD1 is Counteracted by an Increased ER-Lysosomal Network With Impact in Drug-Induced Stress Cell Survival(2022) Vargas, Gabriela; Cortes, Omar; Arias-Munoz, Eloisa; Hernandez, Sergio; Cerda-Troncoso, Cristobal; Hernandez, Laura; Gonzalez, Alexis E.; Tatham, Michael H.; Bustamante, Hianara A.; Retamal, Claudio; Cancino, Jorge; Varas-Godoy, Manuel; Hay, Ronald T.; Rojas-Fernandez, Alejandro; Cavieres, Viviana A.; Burgos, Patricia V.Macroautophagy and the ubiquitin proteasome system work as an interconnected network in the maintenance of cellular homeostasis. Indeed, efficient activation of macroautophagy upon nutritional deprivation is sustained by degradation of preexisting proteins by the proteasome. However, the specific substrates that are degraded by the proteasome in order to activate macroautophagy are currently unknown. By quantitative proteomic analysis we identified several proteins downregulated in response to starvation independently of ATG5 expression. Among them, the most significant was HERPUD1, an ER membrane protein with low expression and known to be degraded by the proteasome under normal conditions. Contrary, under ER stress, levels of HERPUD1 increased rapidly due to a blockage in its proteasomal degradation. Thus, we explored whether HERPUD1 stability could work as a negative regulator of autophagy. In this work, we expressed a version of HERPUD1 with its ubiquitin-like domain (UBL) deleted, which is known to be crucial for its proteasome degradation. In comparison to HERPUD1-WT, we found the UBL-deleted version caused a negative role on basal and induced macroautophagy. Unexpectedly, we found stabilized HERPUD1 promotes ER remodeling independent of unfolded protein response activation observing an increase in stacked-tubular structures resembling previously described tubular ER rearrangements. Importantly, a phosphomimetic S59D mutation within the UBL mimics the phenotype observed with the UBL-deleted version including an increase in HERPUD1 stability and ER remodeling together with a negative role on autophagy. Moreover, we found UBL-deleted version and HERPUD1-S59D trigger an increase in cellular size, whereas HERPUD1-S59D also causes an increased in nuclear size. Interestingly, ER remodeling by the deletion of the UBL and the phosphomimetic S59D version led to an increase in the number and function of lysosomes. In addition, the UBL-deleted version and phosphomimetic S59D version established a tight ER-lysosomal network with the presence of extended patches of ER-lysosomal membrane-contact sites condition that reveals an increase of cell survival under stress conditions. Altogether, we propose stabilized HERPUD1 downregulates macroautophagy favoring instead a closed interplay between the ER and lysosomes with consequences in drug-cell stress survival.
- ItemPathogenicity of lupus anti-ribosomal P antibodies : Role of cross-reacting neuronal surface P antigen in glutamatergic transmission and plasticity in a mouse model(2015) Segovia Miranda, Fabián; Serrano, Felipe; Dyrda, Agnieszka; Ampuero, Estibaliz; Retamal, Claudio; Bravo Zehnder, Marcela; Parodi, Jorge; Zamorano, Pedro; Valenzuela, David; Massardo Vega, Loreto; Van Zundert, Brigitte; Inestrosa Cantín, Nibaldo; González Alfonso
- ItemPhosphatidic Acid Induces Ligand-independent Epidermal Growth Factor Receptor Endocytic Traffic through PDE4 Activation(AMER SOC CELL BIOLOGY, 2010) Norambuena, Andres; Metz, Claudia; Jung, Juan E.; Silva, Antonia; Otero, Carolina; Cancino, Jorge; Retamal, Claudio; Valenzuela, Juan C.; Soza, Andrea; Gonzalez, AlfonsoEndocytosis modulates EGFR function by compartmentalizing and attenuating or enhancing its ligand-induced signaling. Here we show that it can also control the cell surface versus intracellular distribution of empty/inactive EGFR. Our previous observation that PKA inhibitors induce EGFR internalization prompted us to test phosphatidic acid (PA) generated by phospholipase D (PLD) as an endogenous down-regulator of PKA activity, which activates rolipram-sensitive type 4 phosphodiesterases (PDE4) that degrade cAMP. We found that inhibition of PA hydrolysis by propranolol, in the absence of ligand, provokes internalization of inactive (neither tyrosine-phosphorylated nor ubiquitinated) EGFR, accompanied by a transient increase in PA levels and PDE4s activity. This EGFR internalization is mimicked by PA micelles and is strongly counteracted by PLD2 silencing, rolipram or forskolin treatment, and PKA overexpression. Accelerated EGFR endocytosis seems to be mediated by clathrin-dependent and -independent pathways, leading to receptor accumulation in juxtanuclear recycling endosomes, also due to a decreased recycling. Internalized EGFR can remain intracellular without degradation for several hours or return rapidly to the cell surface upon discontinuation of the stimulus. This novel regulatory mechanism of EGFR, also novel function of signaling PA, can transmodulate receptor accessibility in response to heterologous stimuli.
- ItemPhosphatidic acid-PKA signaling regulates p38 and ERK1/2 functions in ligand-independent EGFR endocytosis(2021) Metz, Claudia; Oyanadel, Claudia; Jung, Juan; Retamal, Claudio; Cancino, Jorge; Barra, Jonathan; Venegas, Jaime; Du, Guangwei; Soza, Andrea; Gonzalez, AlfonsoLigand-independent epidermal growth factor receptor (EGFR) endocytosis is inducible by a variety of stress conditions converging upon p38 kinase. A less known pathway involves phosphatidic acid (PA) signaling toward the activation of type 4 phosphodiesterases (PDE4) that decrease cAMP levels and protein kinase A (PKA) activity. This PA/PDE4/PKA pathway is triggered with propranolol used to inhibit PA hydrolysis and induces clathrin-dependent and clathrin-independent endocytosis, followed by reversible accumulation of EGFR in recycling endosomes. Here we give further evidence of this signaling pathway using biosensors of PA, cAMP, and PKA in live cells and then show that it activates p38 and ERK1/2 downstream the PKA inhibition. Clathrin-silencing and IN/SUR experiments involved the activity of p38 in the clathrin-dependent route, while ERK1/2 mediates clathrin-independent EGFR endocytosis. The PA/PDE4/PKA pathway selectively increases the EGFR endocytic rate without affecting LDLR and TfR constitute endocytosis. This selectiveness is probably because of EGFR phosphorylation, as detected in Th1046/1047 and Ser669 residues. The EGFR accumulates at perinuclear recycling endosomes colocalizing with TfR, fluorescent transferrin, and Rab11, while a small proportion distributes to Alix-endosomes. A non-selective recycling arrest includes LDLR and TfR in a reversible manner. The PA/PDE4/PKA pathway involving both p38 and ERK1/2 expands the possibilities of EGFR transmodulation and interference in cancer.
- ItemPrehabilitation for Chilean frail elderly people - pre-surgical conditioning protocol - to reduce the length of stay: randomized control trial(2024) Contreras Ibacache, Víctor; Elgueta Le-beuffe, María Francisca; Balde Sepulveda, Detlef Peter Mario; Astaburuaga Jorquera, Paula Daniela; Carrasco, Marcela; Pedemonte Trewhela, Juan Cristobal; Nicoletti Santoni, Maria Natalia; Medina Díaz, René; Figueroa, Constanza; Alamos Ramirez, Mirelly De Los Angeles; Cuzmar Benítez, Valeria; Vargas Moreno, Benjamin Ignacio; Barraza Mendizabal, Benjamin Juan Pablo; Retamal, Claudio; Cortinez Fernandez, Luis Ignacio; Franco, Sebastián; Agurto, Raul; Vivanco, CatherinBackground: Frail elderly patients have a higher risk of postoperative morbidity and mortality. Prehabilitation is a potential intervention for optimizing postoperative outcomes in frail patients. We studied the impact of a prehabilitation program on length of stay (LOS) in frail elderly patients undergoing elective surgery.Methods: An RCT study was conducted. Frail patients scheduled for elective surgery were randomized to receive either pre-surgical conditioning protocol (PCP) or standard preoperative care. PCP included nursing, anesthetic, and geriatric assessment, nutritional intervention, and physical training for 4-weeks preoperatively. A nurse followed both groups until discharge criteria were met. The primary outcome was postoperative LOS. Secondary outcomes were nutritional status, preoperative frailty status (frailty phenotype-FP) after PCP, and postoperative complications up to three months categorized according to the Clavien-Dindo Classification. Means and medians between the control and intervention groups were compared, with statistical significance set at α=5%.Results: Thirty-four patients were to intervention and Thirty-seven to the control group. In the intervention group, adherence to prehabilitation was 90%. The median LOS after surgery was three days in both groups, without finding statistically significant differences between groups (P=0.754), although there was a trend towards lower LOS in the urologic surgery subgroup. We found a significant reduction in frailty status after PCP (FPpre=2.4±0.5 and FPpost=1.7±0.5, P<0.001). Nutritional status significantly improved in frail patients after prehabilitation (MNAbasal=9.0±2.5 and MNApost=10.6±2.6), P=0.028. The intervention group had less severe postoperative complications, which were not statistically significant.Conclusions: The PCP conducted both in-person and online, for older frail patients undergoing elective colorectal and urological surgery was not associated with shorter LOS. However, frailty status significantly improved after completing PCP.
- ItemSonic hedgehog is basolaterally sorted from the TGN and transcytosed to the apical domain involving Dispatched-1 at Rab11-ARE(2022) Sandoval, Lisette; Labarca, Mariana; Retamal, Claudio; Sanchez, Paula; Larrain, Juan; Gonzalez, AlfonsoHedgehog proteins (Hhs) secretion from apical and/or basolateral domains occurs in different epithelial cells impacting development and tissue homeostasis. Palmitoylation and cholesteroylation attach Hhs to membranes, and Dispatched-1 (Disp-1) promotes their release. How these lipidated proteins are handled by the complex secretory and endocytic pathways of polarized epithelial cells remains unknown. We show that polarized Madin-Darby canine kidney cells address newly synthesized sonic hedgehog (Shh) from the TGN to the basolateral cell surface and then to the apical domain through a transcytosis pathway that includes Rab11-apical recycling endosomes (Rab11-ARE). Both palmitoylation and cholesteroylation contribute to this sorting behavior, otherwise Shh lacking these lipid modifications is secreted unpolarized. Disp-1 mediates first basolateral secretion from the TGN and then transcytosis from Rab11-ARE. At the steady state, Shh predominates apically and can be basolaterally transcytosed. This Shh trafficking provides several steps for regulation and variation in different epithelia, subordinating the apical to the basolateral secretion.
- ItemThe Adaptor Protein-1 μ1B Subunit Expands the Repertoire of Basolateral Sorting Signal Recognition in Epithelial Cells(2013) Guo, Xiaoli; Mattera, Rafael; Ren, Xuefeng; Chen, Yu; Retamal, Claudio; Gonzalez, Alfonso; Bonifacino, Juan S.An outstanding question in protein sorting is why polarized epithelial cells express two isoforms of the mu 1 subunit of the AP-1 clathrin adaptor complex: the ubiquitous mu 1A and the epithelial-specific mu 1B. Previous studies led to the notion that mu 1A and mu 1B mediate basolateral sorting predominantly from the trans-Golgi network (TGN) and recycling endosomes, respectively. Using improved analytical tools, however, we find that mu 1A and mu 1B largely colocalize with each other. They also colocalize to similar extents with TGN and recycling endosome markers, as well as with basolateral cargoes transiting biosynthetic and endocytic-recycling routes. Instead, the two isoforms differ in their signal-recognition specificity. In particular, mu 1B preferentially binds a subset of signals from cargoes that are sorted basolaterally in a mu 1B-dependent manner. We conclude that expression of distinct mu 1 isoforms in epithelial cells expands the repertoire of signals recognized by AP-1 for sorting of a broader range of cargoes to the basolateral surface.
- ItemThe p75 neurotrophin receptor evades the endolysosomal route in neuronal cells, favouring multivesicular bodies specialised for exosomal release(2014) Escudero, Claudia A.; Lazo, Oscal M.; Galleguillos, Carolina; Parraguez, Jose I.; Lopez-Verrilli, Maria A.; Cabeza, Carolina; Leon, Luisa; Saeed, Uzma; Retamal, Claudio; Gonzalez, Alfonso; Marzolo, Maria-Paz; Carter, Bruce D.; Court, Felipe A.; Bronfman, Francisca C.The p75 neurotrophin receptor (p75, also known as NGFR) is a multifaceted signalling receptor that regulates neuronal physiology, including neurite outgrowth, and survival and death decisions. A key cellular aspect regulating neurotrophin signalling is the intracellular trafficking of their receptors; however, the post-endocytic trafficking of p75 is poorly defined. We used sympathetic neurons and rat PC12 cells to study the mechanism of internalisation and post-endocytic trafficking of p75. We found that p75 internalisation depended on the clathrin adaptor protein AP2 and on dynamin. More surprisingly, p75 evaded the lysosomal route at the level of the early endosome, instead accumulating in two different types of endosomes, Rab11-positive endosomes and multivesicular bodies (MVBs) positive for CD63, a marker of the exosomal pathway. Consistently, depolarisation by KCl induced the liberation of previously endocytosed full-length p75 into the extracellular medium in exosomes. Thus, p75 defines a subpopulation of MVBs that does not mature to lysosomes and is available for exosomal release by neuronal cells.