Abstract PO-023: CD70 deregulation in follicular lymphoma at diagnosis is associated with relapse and opens new avenues for dual CD19-CD70 CAR-T therapy
Authors: Araujo-Ayala Ferran , Bachiller Mireia , Alexandru Raluca , Mozas Pablo , Colell Salut , Villalba-Esparza María , Mateos-Jaimez Judith , Nadeu Ferran , Rivero Andrea , Ros Maria , Dobaño-López Cèlia , Valero Juan Garcia , Serrat Neus , Gimenez-Alejandre Marta , Giro Ariadna , Hodson Daniel , López-Guillermo Armando , Campo Elias , Colomer Dolors , Maiques-Diaz Alba , Martín-Subero José Ignacio , Beà Sílvia , Magnano Laura , Guedan Sonia , de Andrea Carlos E. , Pérez-Galan Patricia 
Published: June 2024

Abstract
Follicular lymphoma (FL) is the most common indolent B-cell lymphoma. Despite most patients achieve a complete response with first-line treatment, an important fraction of them relapse, which may worsen the prognosis and increase the risk of a histological transformation to aggressive lymphoma. Therefore, there is a need to better stratify the patients at the diagnosis and develop tailored therapies for high-risk patients. Here we have assessed the immune profile (Nanostring® nCounter) in FFPE-derived biopsies in a series of FL patients at diagnosis, homogenously treated with immunochemotherapy regimen (mostly R-CHOP), and followed-up at Hospital Clínic de Barcelona for more than 12 years. By comparing patients who experienced relapse (n=20) with those who did not relapse at any time (NR, n=12), we have found 31 differentially expressed genes, 25 of them up-regulated in the relapse group. Among them, we have further focused on the role of CD70 in FL pathogenesis. mRNA CD70 was higher in those patients who eventually relapsed and correlated with inferior PFS. Moreover, CD70high FL cases bear a limited number of recurrent somatic mutations. We next sought to determine the specific subpopulations expressing CD70 by multiplex immunofluorescence (Vectra Polaris). Interestingly, we have demonstrated it is mainly expressed in tumor cells correlating with inferior PFS. Moreover, a fraction of T cells from the tumor microenvironment also expresses CD70. Intriguingly, higher levels of CD70 were detected in both CD4+ and CD8+ T cells in the relapse group, including T regulatory and T follicular helper cells. CD70 interacts with CD27, its only known ligand, and can be mutually activated. While CD27 RNA levels did not change between groups, CD27 protein was increased in the B cell population in patients who eventually relapse and in TFH cells, while it was down-regulated in CD8+ and CD4+ T helper non-follicular cells. Furthermore, we found an association between the percentage of CD70+ cells within B cell population and CD70+ in CD4+ and CD8+ cells (R=0.51, p &lt; 0.05). To investigate the role of CD70 in FL pathogenesis we generated two CD70 KO cell lines and FL patient derived cells (n=4) using CRISPR/Cas9 technique. By co-culturing T cells from healthy donors with CD70+ or CD70- FL cell lines, we observed CD70+ tumor cells promote CD70 expression in T cells. In primary samples, we have demonstrated that CD70-KO B cells exhibit reduced response to proliferative stimuli. Moreover, RNAseq analysis followed by GSEA pathway assignment indicated that CD70 expression was related to increased angiogenesis, glycolysis and hypoxia. Finally, to advance towards personalized therapies for this high-risk patient and taking advantage of our institution CAR-T program, we have generated a dual CD19-CD70 CAR-T combining an approved academic product, ARI-0001, and a truncated CD27 protein. Finally, we have demonstrated that this novel CAR-T is effective in both cell lines and ex vivo FL spheroids (PDLS, Dobaño-López, Blood Cancer J 2024), while in vivo studies are ongoing.
Citation Format: Ferran Araujo-Ayala, Mireia Bachiller, Raluca Alexandru, Pablo Mozas, Salut Colell, María Villalba-Esparza, Judith Mateos-Jaimez, Ferran Nadeu, Andrea Rivero, Maria Ros, Cèlia Dobaño-López, Juan Garcia Valero, Neus Serrat, Marta Gimenez-Alejandre, Ariadna Giro, Daniel Hodson, Armando López-Guillermo, Elias Campo, Dolors Colomer, Alba Maiques-Diaz, José Ignacio Martín-Subero, Sílvia Beà, Laura Magnano, Sonia Guedan, Carlos E. de Andrea, Patricia Pérez-Galan. CD70 deregulation in follicular lymphoma at diagnosis is associated with relapse and opens new avenues for dual CD19-CD70 CAR-T therapy [abstract]. In: Proceedings of the Fourth AACR International Meeting on Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2024 Jun 19-22; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(3_Suppl):Abstract nr PO-023.