Centre de Recherche en Cancérologie de Marseille

About: Centre de Recherche en Cancérologie de Marseille is a facility organization based out in . It is known for research contribution in the topics: Biology & Chemistry. The organization has 4 authors who have published 10 publications receiving 27 citations.

Endowing universal CAR T-cell with immune-evasive properties using TALEN-gene editing

Abstract: Abstract Universal CAR T-cell therapies are poised to revolutionize cancer treatment and to improve patient outcomes. However, realizing these advantages in an allogeneic setting requires universal CAR T-cells that can kill target tumor cells, avoid depletion by the host immune system, and proliferate without attacking host tissues. Here, we describe the development of a novel immune-evasive universal CAR T-cells scaffold using precise TALEN-mediated gene editing and DNA matrices vectorized by recombinant adeno-associated virus 6. We simultaneously disrupt and repurpose the endogenous TRAC and B2M loci to generate TCRαβ- and HLA-ABC-deficient T-cells expressing the CAR construct and the NK-inhibitor named HLA-E. This highly efficient gene editing process enables the engineered T-cells to evade NK cell and alloresponsive T-cell attacks and extend their persistence and antitumor activity in the presence of cytotoxic levels of NK cell in vivo and in vitro, respectively. This scaffold could enable the broad use of universal CAR T-cells in allogeneic settings and holds great promise for clinical applications.

Targeting CISH enhances natural cytotoxicity receptor signaling and reduces NK cell exhaustion to improve solid tumor immunity

Abstract: Background The success and limitations of current immunotherapies have pushed research toward the development of alternative approaches and the possibility to manipulate other cytotoxic immune cells such as natural killer (NK) cells. Here, we targeted an intracellular inhibiting protein ‘cytokine inducible SH2-containing protein’ (CISH) in NK cells to evaluate the impact on their functions and antitumor properties. Methods To further understand CISH functions in NK cells, we developed a conditional Cish-deficient mouse model in NK cells ( Cish fl/fl Ncr1 Ki/+ ). NK cells cytokine expression, signaling and cytotoxicity has been evaluated in vitro. Using intravenous injection of B16F10 melanoma cell line and EO711 triple negative breast cancer cell line, metastasis evaluation was performed. Then, orthotopic implantation of breast tumors was performed and tumor growth was followed using bioluminescence. Infiltration and phenotype of NK cells in the tumor was evaluated. Finally, we targeted CISH in human NK-92 or primary NK cells, using a technology combining the CRISPR(i)-dCas9 tool with a new lentiviral pseudotype. We then tested human NK cells functions. Results In Cish fl/fl Ncr1 Ki/+ mice, we detected no developmental or homeostatic difference in NK cells. Global gene expression of Cish fl/fl Ncr1 Ki/+ NK cells compared with Cish +/+ Ncr1 Ki/+ NK cells revealed upregulation of pathways and genes associated with NK cell cycling and activation. We show that CISH does not only regulate interleukin-15 (IL-15) signaling pathways but also natural cytotoxicity receptors (NCR) pathways, triggering CISH protein expression. Primed Cish fl/fl Ncr1 Ki/+ NK cells display increased activation upon NCR stimulation. Cish fl/fl Ncr1 Ki/+ NK cells display lower activation thresholds and Cish fl/fl Ncr1 Ki/+ mice are more resistant to tumor metastasis and to primary breast cancer growth. CISH deletion favors NK cell accumulation to the primary tumor, optimizes NK cell killing properties and decreases TIGIT immune checkpoint receptor expression, limiting NK cell exhaustion. Finally, using CRISPRi, we then targeted CISH in human NK-92 or primary NK cells. In human NK cells, CISH deletion also favors NCR signaling and antitumor functions. Conclusion This study represents a crucial step in the mechanistic understanding and safety of Cish targeting to unleash NK cell antitumor function in solid tumors. Our results validate CISH as an emerging therapeutic target to enhance NK cell immunotherapy.

CRCM5484: A BET-BDII Selective Compound with Differential Anti-leukemic Drug Modulation

Abstract: Differentially screening the Fr-PPIChem chemical library on the bromodomain and extra-terminal (BET) BRD4-BDII versus -BDI bromodomains led to the discovery of a BDII-selective tetrahydropyridothienopyrimidinone (THPTP)-based compound. Structure-activity relationship (SAR) and hit-to-lead approaches allowed us to develop CRCM5484, a potent inhibitor of BET proteins with a preferential and 475-fold selectivity for the second bromodomain of the BRD3 protein (BRD3-BDII) over its first bromodomain (BRD3-BDI). Its very low activity was demonstrated in various cell-based assays, corresponding with recent data describing other selective BDII compounds. However, screening on a drug sensitivity and resistance-profiling platform revealed its ability to modulate the anti-leukemic activity in combination with various FDA-approved and/or in-development drugs in a cell- and context-dependent differential manner. Altogether, the results confirm the originality of the THPTP molecular mode of action in the bromodomain (BD) cavity and its potential as a starting scaffold for the development of potent and selective bromodomain inhibitors.

Therapeutic Targeting of Tumor-Infiltrating Regulatory T Cells in Breast Cancer

Abstract: Regulatory T cells (Treg) are an immunosuppressive subtype of CD4+ T cells essential for maintaining self-tolerance in physiological settings. Tregs also abundantly infiltrate inflamed tumor tissues, impeding the host's antitumor immune response and contributing to tumor growth and metastasis. In breast cancers, subsets of Tregs express highly immunosuppressive effector phenotypes that favor tumorigenesis, progression, and resistance to immune-checkpoint inhibitor therapies. Tregs share phenotypic features with cytotoxic lymphocytes, rendering them difficult to inhibit without compromising productive antitumor immunity. In addition, systemic targeting of Tregs causes serious autoimmune adverse events in patients with cancer. Hence, the identification of candidate targets or methodologies allowing the specific elimination of tumor antigen-specific Tregs, including tumor-infiltrating Tregs, is a prerequisite for developing efficient and safe combinatorial immunotherapeutic strategies in breast cancers. To date, numerous preclinical studies have demonstrated that specific targeting of breast tumor-infiltrating Tregs restores a competent antitumor immune response and improves responses to immune-checkpoint inhibitors such as PD-1/PD-L1 blockade. Herein, we discuss major candidate molecules for Treg-targeted therapeutic strategies in breast cancers, detailing the pros and cons of various approaches, including mAb-mediated depletion, homeostasis destabilization, and functional blockade.

Regulation of Mus81-Eme1 structure-specific endonuclease by Eme1 SUMO-binding and Rad3ATR kinase is essential in the absence of Rqh1BLM helicase

Abstract: The Mus81-Eme1 structure-specific endonuclease is crucial for the processing of DNA recombination and late replication intermediates. In fission yeast, stimulation of Mus81-Eme1 in response to DNA damage at the G2/M transition relies on Cdc2CDK1 and DNA damage checkpoint-dependent phosphorylation of Eme1 and is critical for chromosome stability in absence of the Rqh1BLM helicase. Here we identify Rad3ATR checkpoint kinase consensus phosphorylation sites and two SUMO interacting motifs (SIM) within a short N-terminal domain of Eme1 that is required for cell survival in absence of Rqh1BLM. We show that direct phosphorylation of Eme1 by Rad3ATR is essential for catalytic stimulation of Mus81-Eme1. Chk1-mediated phosphorylation also contributes to the stimulation of Mus81-Eme1 when combined with phosphorylation of Eme1 by Rad3ATR. Both Rad3ATR- and Chk1-mediated phosphorylation of Eme1 as well as the SIMs are critical for cell fitness in absence of Rqh1BLM and abrogating bimodal phosphorylation of Eme1 along with mutating the SIMs is incompatible with rqh1Δ cell viability. Our findings unravel an elaborate regulatory network that relies on the poorly structured N-terminal domain of Eme1 and which is essential for the vital functions Mus81-Eme1 fulfills in absence of Rqh1BLM.