Julie Guillermet-Guibert

SigDYN :

Integrated cellular signalling and PI3K isoforms

the specifities

of our research axis


The team directed by J Guillermet-Guibert studies the family of lipid kinases known as phosphoinositide 3-kinases (PI3Ks) from different angles. This family of enzymes is involved in major cellular functions such as cell survival, proliferation, growth, migration, differentiation but also protein synthesis and intracellular vesicular trafficking. In vertebrates, the PI3K family is divided into three different classes. This classification is based on their structure, mode of activation and lipid substrate specificity in vitro and in vivo. These enzymes, encoded by 8 different genes, all phosphorylate the hydroxyl group in position 3 of the inositol ring of phosphoinositides, hence their name.

Only class I (composed of PI3Kα, PI3Kβ, PI3Kγ, PI3Kδ) can convert phosphatidylinositol (4,5)-bisphosphate [PtdIns-4,5-P2, PtdIns (4,5) P2, PIP2] to phosphatidylinositol (3,4,5)-trisphosphate [PtdIns-3,4,5-P3, PtdIns (3,4,5) P3, PIP3]. The substrate of class I enzymes is mainly located at the cell membrane. Thus, activation of class I PI3Ks produces a lipid second messenger at the plasma membrane at the interface with the cytoplasm, which allows the transmission of biochemical information into the cytoplasm and leads to a cellular response.

Class II (PI3KC2α, PI3KC2β, PI3KC2γ) and class III (VPS34) PI3Ks can generate phosphatidylinositol 3-phosphate [PtdIns-3-P, PtdIns (3) P, PI-3-P]. Class II PI3Ks can also synthesise phosphatidylinositol (3,4)-bisphosphate [PtdIns-3, 4-P2, PtdIns (3,4) P2]. The substrates of these enzymes are present in the outer membranes of organelles within the cell, at the level of endosomes, autophagosomes. Thus, class II and III PI3Ks control intracellular vesicular trafficking.

The high activation of class I PI3Ks is considered to be a characteristic of cancer; however, the role of each class I PI3K in the different stages of carcinogenesis is poorly understood. This research is carried out by our team.

The roles of class II and III PI3Ks in cancer are poorly studied. We have undertaken to understand them.

We mostly apply our research to solid cancers such as pancreatic cancer to better understand, earlier diagnose and treat this deadly disease. We also work on ovarian cancers and collaborate with teams working on liquid cancers.


Oncogenic signalling


Targeted therapies


Tumour niche

Cancer initiation



Genetically modified mice

Tumour imaging

Pancreatic cancer

Ovarian cancer




Despas, Fabien, Maria Chaouki, Sandra de Barros, Baptiste Bonneau, Ben Allal, Julie Guillermet-Guibert, and Loïc Ysebaert. “Pharmacokinetics of Idelalisib in Chronic Lymphocytic Leukemia and Follicular Lymphoma Disclose Better Outcomes for Patients with Lower Exposure.” Leukemia & Lymphoma, May 15, 2024, 1–3.
Fébrissy, Chanaëlle, Marine Adlanmerini, Christel Péqueux, Frédéric Boudou, Mélissa Buscato, Adrien Gargaros, Silveric Gilardi-Bresson, et al. “Reprogramming of Endothelial Gene Expression by Tamoxifen Inhibits Angiogenesis and ERα-Negative Tumor Growth.” Theranostics 14, no. 1 (2024): 249–64.
Schmitter, Céline, Mickaël Di-Luoffo, and Julie Guillermet-Guibert. “Transducing Compressive Forces into Cellular Outputs in Cancer and Beyond.” Life Science Alliance 6, no. 9 (September 2023): e202201862.
Nicco, Carole, Marine Thomas, Julie Guillermet, Maryline Havard, Fanny Laurent-Tchenio, Ludivine Doridot, François Dautry, Frédéric Batteux, and Thierry Tchenio. “Mechanistic Target of Rapamycin (MTOR) Regulates Self-Sustained Quiescence, Tumor Indolence, and Late Clinical Metastasis in a Beclin-1-Dependent Manner.” Cell Cycle (Georgetown, Tex.) 22, no. 5 (March 2023): 542–64.
Thibault, Benoît, Fernanda Ramos-Delgado, and Julie Guillermet-Guibert. “Targeting Class I-II-III PI3Ks in Cancer Therapy: Recent Advances in Tumor Biology and Preclinical Research.” Cancers 15, no. 3 (January 27, 2023): 784.
Ben Meriem, Zacchari, Tiphaine Mateo, Julien Faccini, Céline Denais, Romane Dusfour-Castan, Catherine Guynet, Tatiana Merle, et al. “A Microfluidic Mechano-Chemostat for Tissues and Organisms Reveals That Confined Growth Is Accompanied with Increased Macromolecular Crowding.” Lab on a Chip 23, no. 20 (2023): 4445–55.
Chaves-Almagro, Carline, Johanna Auriau, Alizée Dortignac, Pascal Clerc, Hubert Lulka, Simon Deleruyelle, Fabrice Projetti, et al. “Upregulated Apelin Signaling in Pancreatic Cancer Activates Oncogenic Signaling Pathways to Promote Tumor Development.” International Journal of Molecular Sciences 23, no. 18 (September 13, 2022): 10600.
Cintas, Célia, Thibault Douche, Zahra Dantes, Emmanuelle Mouton-Barbosa, Marie-Pierre Bousquet, Coralie Cayron, Nicole Therville, et al. “Phosphoproteomics Identifies PI3K Inhibitor-Selective Adaptive Responses in Pancreatic Cancer Cell Therapy and Resistance.” Molecular Cancer Therapeutics 20, no. 12 (December 2021): 2433–45.
Di-Luoffo, M., Z. Ben-Meriem, P. Lefebvre, M. Delarue, and J. Guillermet-Guibert. “PI3K Functions as a Hub in Mechanotransduction.” Trends in Biochemical Sciences 46, no. 11 (November 2021): 878–88.
Cayron, C., S. Rigal, and J. Guillermet-Guibert. “Is Targeting Autophagy a Promising Lead to Unveil the Cloak of Invisibility in Pancreatic Cancer?” Clinics and Research in Hepatology and Gastroenterology 45, no. 6 (November 2021): 101622.
Thibault, Benoit, Fernanda Ramos-Delgado, Elvire Pons-Tostivint, Nicole Therville, Celia Cintas, Silvia Arcucci, Stephanie Cassant-Sourdy, et al. “Pancreatic Cancer Intrinsic PI3Kα Activity Accelerates Metastasis and Rewires Macrophage Component.” EMBO Molecular Medicine 13, no. 7 (July 7, 2021): e13502.
Arcucci, Silvia, Fernanda Ramos-Delgado, Coralie Cayron, Nicole Therville, Marie-Pierre Gratacap, Céline Basset, Benoit Thibault, and Julie Guillermet-Guibert. “Organismal Roles for the PI3Kα and β Isoforms: Their Specificity, Redundancy or Cooperation Is Context-Dependent.” The Biochemical Journal 478, no. 6 (March 26, 2021): 1199–1225.
Mazloumi Gavgani, Fatemeh, Thomas Karlsson, Ingvild L. Tangen, Andrea Papdiné Morovicz, Victoria Smith Arnesen, Diana C. Turcu, Sandra Ninzima, et al. “Nuclear Upregulation of Class I Phosphoinositide 3-Kinase P110β Correlates with High 47S RRNA Levels in Cancer Cells.” Journal of Cell Science 134, no. 3 (February 10, 2021).
Rizzuti, Ilaria Francesca, Pietro Mascheroni, Silvia Arcucci, Zacchari Ben-Mériem, Audrey Prunet, Catherine Barentin, Charlotte Rivière, et al. “Mechanical Control of Cell Proliferation Increases Resistance to Chemotherapeutic Agents.” Physical Review Letters 125, no. 12 (September 18, 2020): 128103.
Hakobyan, Davit, Chantal Médina, Nathalie Dusserre, Marie-Laure Stachowicz, Charles Handschin, Jean-Christophe Fricain, Julie Guillermet-Guibert, and Hugo Oliveira. “Laser-Assisted 3D Bioprinting of Exocrine Pancreas Spheroid Models for Cancer Initiation Study.” Biofabrication 12, no. 3 (April 16, 2020): 035001.
Cayron, Coralie, and Julie Guillermet-Guibert. “The Type of KRAS Mutation Drives PI3Kα/γ Signalling Dependency: Implication for the Choice of Targeted Therapy in Pancreatic Adenocarcinoma Patients.” Clinics and Research in Hepatology and Gastroenterology, 2020, S2210740120301662.
Zamora, Audrey, Melinda Alves, Charlotte Chollet, Nicole Therville, Tiffany Fougeray, Florence Tatin, Camille Franchet, et al. “Paclitaxel Induces Lymphatic Endothelial Cells Autophagy to Promote Metastasis.” Cell Death & Disease 10, no. 12 (December 20, 2019): 956.
Müller, David, Sauyeun Shin, Théo Goullet de Rugy, Rémi Samain, Romain Baer, Manon Strehaiano, Laia Masvidal-Sanz, et al. “EIF4A Inhibition Circumvents Uncontrolled DNA Replication Mediated by 4E-BP1 Loss in Pancreatic Cancer.” JCI Insight 4, no. 21 (November 1, 2019).
Therville, Nicole, Silvia Arcucci, Aurélie Vertut, Fernanda Ramos-Delgado, Dina Ferreira Da Mota, Marlène Dufresne, Céline Basset, and Julie Guillermet-Guibert. “Experimental Pancreatic Cancer Develops in Soft Pancreas: Novel Leads for an Individualized Diagnosis by Ultrafast Elasticity Imaging.” Theranostics 9, no. 22 (2019): 6369–79.

team members

Corentin Bouvier
Doctorant / PhD student
Silvia Arcucci
Ingénieur de laboratoire / laboratory engineer
Ingénieur de laboratoire / laboratory engineer
Sanzhar Aitbay
Doctorant / PhD student
Maria Chaouki
Doctorant / PhD student
Julien Faccini
Ingénieur de laboratoire / laboratory engineer
Hala Shalhoub
Chercheur Post-Doctorant / Post-Doc researcher
Julie Guillermet-Guibert
Chercheur statutaire / permanent scientist
Nicole Therville
Ingénieur de laboratoire / laboratory engineer
Benoît Thibault
Chercheur statutaire / permanent scientist
Mickael Di-Luoffo
Chercheur Post-Doctorant / Post-Doc researcher
Camille Guyon
Doctorant / PhD student
Coralie Cayron
Doctorant / PhD student


Centre de Recherches en Cancérologie de Toulouse

Centre de Recherches en Cancérologie de Toulouse (Oncopole)

Toulouse – FR

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