Validation and Identification of New Targets in cancer and AGEing (VINTAGE)
Group of Metabolism and Cell Signaling — Raul V. Duran (CR1, INSERM)
Raul V. Duran obtained his PhD at the University of Seville (Spain) in 2005 on cellular bioenergetics. Then, he joined the lab of Prof. Eyal Gottlieb at Cancer Research UK (Glasgow, UK) as a postdoctoral researcher (2006-2009) to work on the metabolism of cancer cells. Later, he moved to the lab of Prof. Michael N. Hall at the Biozentrum (University of Basel, Switzerland) as a senior postdoc (2010-2013) to study the role of the metabolism of glutamine in the control of cell growth. In June 2013, he joined the U1218 Unit as a Junior Group Leader of the Institut Européen de Chimie et Biologie, focusing on the crosstalk between metabolism and cell signaling in cancer cells.
We study the mechanisms by which the de-regulation of cell signaling contributes to metabolic transformation in cancer. Particularly, we focus our research on the regulation of glutamine metabolism (glutaminolysis) by the mTORC1 pathway (a master regulator of cell growth) in cancer cells. First, we investigate the biochemical and cellular mechanisms of the interaction between glutaminolysis and mTORC1. Second, we study the interplay between glutamine metabolism and mTORC1 in cancer models of lymphoblastic leukemia. Third, we analyze the role of glutamine-dependent activation of mTORC1 in cell death and senescence in cancer models.
Despite the role of both glutaminolysis and mTORC1 in the promotion of cell growth, we recently observed that the unbalanced activation of the glutaminolysis/mTORC1 pathway in the absence of other amino acids induced apoptotic cell death in human cells. We termed this unusual type of cell death as “glutamoptosis”. During glutamoptosis, the long-term production of glutaminolysis-derived αKG in the absence of other amino acids was sufficient to activate mTORC1 and to inhibit autophagy, but concomitantly reduced cell viability and activated apoptosis. Inhibition of mTORC1 or re-activation of autophagy were sufficient to suppress the glutaminolysis-induced apoptosis. We additionally observed that the ability of rapamycin to prevent apoptosis resides in its pro-autophagic potential: re-inhibition of autophagy prevented cell survival in rapamycin-treated cells. The surprising role of glutaminolysis as a cell death inducing mechanism during nutrient restriction points at the importance of nutritional imbalance in the control of cell viability and the potential use of this metabolic disequilibrium to identify new metabolic components and targets with potential implication in the treatment of nutrition-related diseases, such as obesity, diabetes, cancer, or cardiovascular diseases. In any case, whether the activation of apoptosis by the unbalanced activation of glutaminolysis and mTORC1 plays an active role in the biochemical basis of those diseases is a question that remains to be elucidated.
Recent selected publications
Villar VH & Durán RV (2017) Glutamoptosis: a new cell death mechanism inhibited by autophagy during nutritional imbalance. Autophagy, in press.
Villar VH, Nguyen TL, Delcroix V, Terés S, Bouchecareilh M, Salin B, Bodineau C, Vacher P, Priault M, Soubeyran P and Durán RV (2017) mTORC1 inhibition in cancer cells protects from glutaminolysis-mediated apoptosis during nutrient limitation. Nature Comm. 8, 14124.
Nguyen TL and Durán RV (2016) Prolyl hydroxylase domain enzymes and their role in cell signaling and cancer metabolism. Int. J. Biochem. Cell Biol. 80, 71-80.
Villar VH, Mehri F, Djavaheri-Mergny M and Durán RV (2015) Glutaminolysis and autophagy in cancer. Autophagy 11, 1198-208.
Durán RV, MacKenzie EM, Boulahbel H, Frezza C, Tardito S, Heiserich L, Bussolati O, Rocha S, Hall MN and Gottlieb E (2013) HIF-independent role of prolyl hydroxylases in the cellular response to amino acids. Oncogene 32, 4549-56.
Durán RV, Oppliger W, Robitaille AM, Heiserich L, Skendaj R, Gottlieb E and Hall MN (2012) Glutaminolysis activates Rag-mTORC1 signaling. Mol. Cell 47, 349-58.
Oncogenic roles of calcium signaling. Implication in resistance to chemotherapeutic treatment and in metastasis
Calcium ions and resistance to treatment (Pierre Vacher, Laurence Bresson-Bépoldin)
Apoptosis is essential for organ and tissue homeostasis. Furthermore, age-related diseases including cancer, auto-immunity and diabetes occur when apoptotic processes are impaired. Resistance to apoptosis occurs both during tumorigenesis and tumour relapse following chemotherapeutic treatment. Numerous anti-tumour agents eliminate cancer cells by activation of the death receptor pathways. Hence, the restoration or amplification of these apoptotic pathways is a topic of great interest in oncology. To achieve this, we need to better understand the mechanisms of death receptor activation. We have recently shown that calcium ions play an unexpected role in the regulation of apoptosis. Specifically, we have shown that the CD95/Fas death receptor ligands trigger a calcium-mediated negative feedback loop preventing death signaling (1).
Traditional chemotherapies induce major side effects because they target both cancerous and non-cancerous dividing cells. Fortunately, they are being supplemented by a new generation of “targeted” drugs. These are more specific and several have already been approved for use in malignancies, including non-Hodgkin lymphomas (NHL). For example, Rituximab (Mabthéra™ ou Rituxan™, Roche), a monoclonal anti-CD20 antibody targeting B lymphocytes, is currently used alone or in combination with standard chemotherapeutic regimens to treat NHL. We have shown in vitro and in vivo that the pro-apoptotic effect of Rituximab can be significantly increased when intra- or extra-cellular calcium concentration is decreased. It thus appears that combination therapy with a hypocalcemic agent can potentiate the therapeutic effect of Rituximab without triggering major side effects (2). This reduced toxicity offers a promising approach for the treatment of fragile elderly patients. Future work (with Dr. F. Bijou, institut Bergonié) will explore the association of hypocalcemic agents with a novel glycoengineered type II anti-CD20 monoclonal antibody, GA101 (Obinutuzumab, Roche).
Klotho and IGF1 (Pierre Vacher)
The klotho gene was identified as an “aging-suppressor” gene in mice that accelerates aging when disrupted and extends life span when overexpressed. Mice lacking Klotho display a premature-aging syndrome. Klotho gene also appears as a “tumor suppressor” gene. In collaboration with the Sarcoma group (Frédéric Chibon, Institut Bergonié), we have established Klotho-overexpressing dedifferentiated liposarcoma cell lines. We have observed that these cells have a better apoptotic response to the BH3 mimetics (ABT), Thapsigargin (TG) and to a lesser extent, Gemcitabine, than under expressing cells. Our preliminary results suggest that this effect is linked to an IGF1R-dependent mechanism of regulation of the intra-reticular calcium concentration.
Calcium ions and cell migration (Pierre Vacher)
Cancer metastasis is the major cause of cancer morbidity and mortality, and accounts for about 90% of cancer deaths. Limited progress has been made in the treatment of cancer metastasis. New approaches in the treatment of cancer metastasis are needed.
We were among the first authors to show that activation of a death receptor (CD95, for example) doesn’t necessarily leads to apoptosis but also to survival mechanisms such as cell migration, according to the nature of the ligand (3-5). Indeed, we show that (i) a metalloprotease-cleaved CD95L (Cl-CD95L) is increased in sera of systemic lupus erythematosus (SLE, auto-immune disease) patients (age-matched) (3, 4) and of patients suffering from Triple-negative breast cancer (TNBC) (5), (ii) it promotes cell migration through a c-yes/Ca²⁺/PI3K-driven signaling pathway (3), and (iii) is associated with increased risk of developing distant metastases (5). By a structure/function study, we have identified the region of the receptor involved in the calcium signal initiation, pase to evoke a Ca2+ response. We generated a cell-penetrating CID peptide, TAT-CID, which competes with CD95 to bind PLCg1 and blocks the calcium signal, prevents Th17 cell transmigration and alleviates clinical symptoms in lupus-prone mice (3), an animal model for SLE. In vitro, TAT-CID also blocks the migration of TNBC cells. Future work will explore the effects of TAT-CID on the metastatic effects of cl-CD95L in TNBC-xenografted mice. Therefore, neutralizing the CD95 non-apoptotic signaling pathway turns out to be a novel and attractive therapeutic approach for auto-immune disease and cancer treatment. This work is the subject of patents (6-7). Using calcium responses, CD95/PLCg interactions, and migration assays as read-out, we have screened chemical libraries to find inhibitors of the CD95 non-apoptotic signaling pathway. Several hits were identified in the Prestwick library, 2 are currently under investigation. A company (APOFAS Biotech) was crdesignated calcium-inducing domain (CID) (4). CD95-CID directly interacts with the SH3 domain of phospholipase Cγ1 (PLCγ1), recruiting the lieated to exploit the therapeutic abilities of these molecules. Note that age-dependent changes of serum CD95L levels were demonstrated.
Bcl2 family proteins and calcium flux from ER to mitochondria
We have recently demonstrated that the anti-apoptotic factors Bcl-2 and BclxL collaborate to induce CD95-mediated mitochondrial Ca2+ upload, increasing ATP production and thereby promoting cell migration in TNBC (8). This study reveals a novel molecular mechanism controlled by BclxL to promote cancer cell migration and supports the use of BH3 mimetics as therapeutic options not only to kill tumor cells but also to prevent metastatic dissemination in TNBCs. Therefore, tumor cells are not only selected according to their ability to resist apoptotic signaling pathways but also their capacity to use this “apoptotic machinery” in order to become more aggressive and thus metastatic. Navitoclax, also designated ABT-263, is an orally bioavailable derivative of ABT-737 that unfortunately showed side effects such as thrombocytopenia in phase II clinical trials. Our results indicate that a combination of low doses of navitoclax with classical chemotherapy applied in TNBC women (i.e., taxanes and anthracyclines) is an attractive therapeutic option not only to reduce the risk of metastatic dissemination in patients with a high serum concentration of Cl-CD95L but also to decrease the side effects observed when this drug is used at cytotoxic doses.
Figure 3: CD95-mediated cell migration occurs through a Bcl2/BclxL/VDAC1/MCU-driven mitochondrial calcium loading.
|Death inducing signaling complex (DISC) and Motility inducing signaling complex (MISC) are formed through protein/protein interaction. For the CD95-mediated apoptotic signaling pathway, type II cells (e.g., hepatocytes) rely on the release of apoptotic factors (i.e., cytochrome c, smac/Diablo, Omi/Hrt2A) by the mitochondria to implement the apoptotic cue while Type I (e.g., T lymphocytes) does not. The CD95-mediated calcium response is initiated by PLCγ1 activation leading to release of the ER-stored Ca2+ in the cytosol (1), followed by a Store-operated calcium entry (SOCE) through activation of the Ca2+ channel Orai1 (2). This study shows the pivotal role played by the calcium transfer from ER to mitochondria (3) in TNBC cell migration induced by cl-CD95.|
1. Khadra N*, Bresson-Bepoldin L*, Chaigne Delalande B*, Penna A, Cahalan MD, Ségui B, Levade T, Vacher AM, Reiffers J, Ducret T, Moreau JF, Vacher P¥ and Legembre P¥.*premiers co-auteurs, ¥derniers co-auteurs. Identification of a CD95-mediated negative feedback loop that hinders the DISC formation through an Orai1-Ca2+-PKCb2 signaling pathway. PNAS 108: 19072-19077, 2011 IF 9.737
Editor’s choice Foley JF Applying the brakes with calcium Sc. Signal. 4: ec330, 2011
2. Vacher P, Vacher A-M, Pineau R, Latour S, Soubeyran I, Pangault C, Tarte K, Soubeyran P, Ducret T, and Bresson-Bepoldin L. Localized store-operated calcium influx represses CD95-dependent apoptotic effects of Rituximab in Non-Hodgkin B lymphomas. J Immunol. 195: 2207-2215, 2015 IF 5.362
Top 10% J Immunol. 195:1907-1908
3. Tauzin S, Chaigne-Delalande B, Selva E, Khadra N, Daburon S, Contin-Bordes C, Blanco P, Le Seyec J, Ducret T, Counillon L Moreau J-F, Hofman P, Vacher P and Legembre P. The naturally processed CD95L elicits a c-yes/calcium/PI3K-driven cell migration pathway PLoS Biol, 9 (6):e1001090, 2011. IF 11.452
4. Sanséau D, Poissonier A, Malleter M, Le Gallo M, Levoin N, Penna A, , Blanco P, Dupuy A, Poizeau F, Fautrel A, Viel R, Séneschal J, Contin C, Ducret T, Vacher A-M, Levoin N, Flynn R, Vacher P ¶ and Legembre P ¶ co-derniers auteurs¶.Inhibition of CD95-mediated Ca2+ signaling prevents Th17 cell recruitment to inflamed tissues, and alleviates clinical symptoms in lupus-prone mice Therapeutic targeting of CD95-mediated Ca2+ signaling alleviates clinical symptoms in lupus-prone mice. Immunity, 45: 209-223, 2016, IF 24,08
Highlighted in Nature Reviews Rheumatology by the associate editor Dr J. Collison
5. Malleter M, Tauzin S, Bessede A, Castellano R, Goubard A, Godey F, Leveque J, Jezequel P, Campion L, Campone M, Ducret T, Macgrogan G, Debure L, Colette Y, Vacher P, and Legembre P. CD95L cell surface cleavage triggers a pro-metastatic signalling pathway in triple negative breast cancer. Cancer Research, 73:6711-6721, 2013, IF 7.856
6. Patent: Vacher P, Legembre P, Levoin N. Peptides and uses thereof for reducing CD95-mediated cell motility, EP16 305 242.6, US N°09-148
7. Patent: Vacher P, Legembre P, Amanda Poissonnier. Methods and pharmaceutical compositions for reducing CD95-mediated cell motility WO2015189236 – EP17305047.7
8. Fouqué A, Lepvrier E, Debure L, Gouriou Y, Malleter M, Delcroix V, Ovize M, Ducret T, Li C, Hammadi M, Vacher, P ¶, and Legembre P ¶.co- derniers auteurs¶. The apoptotic members CD95, BclxL, and Bcl-2 cooperate to promote cell migration by inducing Ca2+ flux from the endoplasmic reticulum to mitochondria. Cell Death and Differentiation 23:1702-1716, 2016. IF 8.184
I. Charles E, Hammadi M, Kischel, Delcroix V, Demaurex N, Castelbout C, Vacher A-M, Devin A, Ducret T, Nunes P and Vacher P. The antidepressant fluoxetine induces necrosis by energy depletion and mitochondrial calcium overload. Oncotarget doi: 10.18632/oncotarget.13689, IF 6.63
II. Hammadi M, Delcroix V, Vacher AM, Ducret T, Vacher P. CD95-mediated calcium signaling. Methods in Molecular Biology 1557: 79-93, IF 1.5