Centro Interdipartimentale di Biotecnologie Molecolari "Guido Tarone"
Tiziana Vaisitti - PI
2021 to date Associate Professor of Medical Genetics, Dept. of Medical Sciences, University of Torino, Italy
Lorenzo Brandimarte PhD Student
Giulia Omezzolli Post-graduate Fellow
Francesco Edoardo Vallone Post-graduate Fellow
Research activity
The Research Unit is focused on two distinct topics: Richter’s syndrome, a hematological cancer, and monogenic diseases leading to organ failure. Even though they appear as distinct fields of interest, there is a common denominator: the use of “omics” and functional approaches to understand pathogenetic mechanisms underlying the diseases. Richter’s syndrome (RS) is a high-grade lymphoma occurring in 10-12% of patients diagnosed with chronic lymphocytic leukemia, the most frequent leukemia in Western countries. RS is a clinical need since the current chemotherapeutic regimes result in no or limited responses. Our research is focused on the understanding of mechanisms characterizing RS cells biology and contributing to disease aggressiveness, with the final goal of identifying potential targets to be translated into the clinics. To this, we are exploiting both primary cells and patient-derived xenograft (RS-PDX) models, that recapitulate the human disease allowing for functional analyses and genetic manipulation. Moreover, PDXs are useful tools to preclinically validate the impact of selective drugs. Primary RS cells and PDXs have been characterized from the genetic and transcriptomic points of view. The profiling of these cells and models allowed us to i) obtain a fingerprint of RS, ii) identify critical biological features (e.g., cellular metabolism, RNA translation) and iii) pinpoint molecular pathways that are detrimentally activated (e.g., apoptosis) or molecules that are aberrantly expressed (e.g., CD37, ROR1). We are currently validating and molecularly characterize these pathways to understand their pathogenic role and whether they can be exploited in a translational perspective (Figure 1).
In line with this view, recently, we have shown that RS cells are characterized by the expression of selective receptors whose expression is restricted to cancer cells, making them good candidates for targeting approaches. By exploiting RS-PDXs, we proved the ex-vivo and in vivo efficacy of antibody-drug conjugates (ADCs) targeting these receptors (Figure 2).
The second main topic of investigation of the Research Unit is the identification, by sequencing approaches, of variants relevant for the diagnosis of rare genetic diseases responsible for organ failure and their functional validation to better understand their clinical impact and meaning. Approximately 80% of all rare diseases have a genetic background and most of them are monogenic conditions.
Early diagnosis and specific treatments can improve patients’ quality of life. Transplantation is among the therapeutic options and represents the definitive treatment for end-stage organ failure, both in children and adults. A significant number of patients in transplant waiting lists is affected by rare monogenic diseases, while approximately 20% of them are undiagnosed. We are applying a clinical exome sequencing based approach to uncover genetic variants that lead to organ failure, thus ultimately requiring organ transplantation. This approach allows the identification of causative genetic variants in a significant proportion of patients. However, one of the main drawbacks of applying sequencing technology in the diagnostic feld, is the identification of the so called “variants of unknown significance - VUS”, meaning that their role in contributing to the disease remains to be defined. This classification poses questions on the biological meaning of the identified variants and whether they may be involved in the pathogenesis of the disease. To address this point, it is crucial to reproduce these variants using gene editing approaches (e.g., CRISPR/Cas9) to generate ad hoc cellular models that allow for functional validation of the identified variants and ultimately to understand their role in the disease (Figure 3).
This approach is currently used to validate VUS variants identified in patients with kidney diseases (e.g., polycystic kidney disease, hypocalciuric hypercalcemia). This part of the research is performed in a joint effort with the group of Prof. Deaglio.
Regarding the first topic, the available DNA and RNA sequencing data are a treasure trove of information and may open for novel paths of investigation. Specifically, we plan to more deeply characterize those pathways that emerged as the most differentially expressed between the CLL and RS phases and that contribute to the aberrant behavior of these neoplastic cells (e.g., DNA repair mechanisms, migration, apoptosis). Molecular characterization is a necessary step to explore novel therapeutic opportunities. Regarding the second topic, we plan to investigate the genetic basis of the clinical heterogeneity typical of some monogenic diseases by re-analyzing genetic data and looking for variants, besides the causative ones, in genes that may act as disease modifiers and characterize their role.
Italian Ministry of Health, Young Investigator Grant “Analysis of the in vitro and in vivo role of ET-1/ETAR and CD38/CD31 axes in chronic lymphocytic leukemia: prognostic, functional and therapeutic implications”
Italian Ministry of Health, Young Investigator Grant “Highlighting the tumorigenic role of long non-coding RNA in patients with Anaplastic Large cell Lymphoma”.
Italian Association for Cancer Research (AIRC) – My First AIRC Grant “Probing Richter’s syndrome by multiple “omics” approaches to fund its Achilles heel”.
Fondazione CRT - Erogazioni Ordinarie 2021 “Analysis of the therapeutic response of Richter’s syndrome cells: targeting novel molecular players”.
Fondazione Ricerca Molinette – Ricerca Scientifca d’Eccellenza “DeRiMe – Deciphering Richter’s Syndrome Metabolism to identify novel therapeutic opportunities”.
Progetti di Rilevanza Nazionale – PRIN 20229LATWH “Cell homing and apoptosis resistance in Richter’s syndrome: 2 features opening translational opportunities”
Vaisitti T, Gaudino F, Ouk S, Moscvin M, Vitale N, Serra S, Arruga F, Zakrzewski JL, Liou HC, Allan JN, Furman RR, Deaglio S. “Targeting metabolism and survival in chronic lymphocytic leukemia and Richter syndrome cells by a novel NF-κB inhibitor.” Haematologica. 2017 Nov;102(11):1878-1889. doi: 10.3324/haematol.2017.173419
Vaisitti T, Braggio E, Allan JN, Arruga F, Serra S, Zamò A, Tam W, Chadburn A, Furman RR, Deaglio S. “Novel Richter Syndrome Xenograf Models to Study Genetic Architecture, Biology, and Therapy Responses.” Cancer Res. 2018 Jul 1;78(13):3413-3420. doi: 10.1158/0008-5472.CAN-17-4004
Vaisitti T, Arruga F, Vitale N, Lee TT, Ko M, Chadburn A, Braggio E, Di Napoli A, Iannello A, Allan JN, Miller LL, Lannutti BJ, Furman RR, Jessen KA, Deaglio S. “ROR1 targeting with the antibody-drug conjugate VLS-101 is efective in Richter syndrome patient-derived xenograf mouse models.” Blood. 2021 Jun 17;137(24):3365- 3377. doi: 10.1182/blood.2020008404.
Iannello A, Vitale N, Coma S, Arruga F, Chadburn A, Di Napoli A, Laudanna C, Allan JN, Furman RR, Pachter JA, Deaglio S, Vaisitti T. “Synergistic eficacy of the dual PI3K-δ/γ inhibitor duvelisib with the Bcl-2 inhibitor venetoclax in Richter syndrome PDX models.” Blood. 2021 Jun 17;137(24):3378-3389. doi: 10.1182/ blood.2020010187.
Chakraborty S, Martines C, Porro F, Fortunati I, Bonato A, Dimishkovska M, Piazza S, Yadav BS, Innocenti I, Fazio R, Vaisitti T, Deaglio S, Zamò A, Dimovski AJ, Laurenti L, Efremov DG. “B-cell receptor signaling and genetic lesions in TP53 and CDKN2A/ CDKN2B cooperate in Richter transformation.” Blood. 2021 Sep 23;138(12):1053-1066. doi: 10.1182/ blood.2020008276.
Vaisitti T, Vitale N, Micillo M, Brandimarte L, Iannello A, Papotti MG, Jaksic O, Lopez G, Di Napoli A, Cutrin JC, Orlik C, Kulke M, Pahl A, Deaglio S. “Anti-CD37 α-amanitin-conjugated antibodies as potential therapeutic weapons for Richter syndrome.” Blood. 2022 Sep 29;140(13):1565-1569. doi: 10.1182/ blood.2022016211.
Martines C, Chakraborty S, Vujovikj M, Gobessi S, Vaisitti T, Deaglio S, Laurenti L, Dimovski AJ, Efremov DG. “Macrophage- and BCR-derived but not TLR-derived signals support the growth of CLL and Richter syndrome murine models in vivo.” Blood. 2022 Dec 1;140(22):2335-2347. doi: 10.1182/blood.2022016272.
Vaisitti T, Sorbini M, Callegari M, Kalantari S, Bracciamà V, Arruga F, Vanzino SB, Rendine S, Togliatto G, Giachino D, Pelle A, Cocchi E, Benvenuta C, Baldovino S, Rollino C, Fenoglio R, Sciascia S, Tamagnone M, Vitale C, Calabrese G, Biancone L, Bussolino S, Savoldi S, Borzumati M, Cantaluppi V, Chiappero F, Ungari S, Peruzzi L, Roccatello D, Amoroso A, Deaglio S. “Clinical exome sequencing is a powerful tool in the diagnostic fow of monogenic kidney diseases: an Italian experience.” J Nephrol. 2021 Oct;34(5):1767-1781. doi: 10.1007/s40620-020-00898-8.
Vaisitti T, Peritore D, Magistroni P, Ricci A, Lombardini L, Gringeri E, Catalano S, Spada M, Sciveres M, Di Giorgio A, Limongelli G, Varrenti M, Gerosa G, Terzi A, Pace Napoleone C, Amodeo A, Ragni L, Dello Strologo L, Benetti E, Fontana I, Testa S, Peruzzi L, Mitrotti A, Abbate S, Comai G, Gotti E, Schiavon M, Bofini M, De Angelis D, Bertani A, Pinelli D, Torre M, Poggi C, Deaglio S, Cardillo M, Amoroso A. “The frequency of rare and monogenic diseases in pediatric organ transplant recipients in Italy.” Orphanet J Rare Dis. 2021 Sep 4;16(1):374. doi: 10.1186/s13023-021-02013-x.
Vaisitti T, Bracciamà V, Faini AC, Brach Del Prever GM, Callegari M, Kalantari S, Mioli F, Romeo CM, Luca M, Camilla R, Mattozzi F, Gianoglio B, Peruzzi L, Amoroso A, Deaglio S. “The role of genetic testing in the diagnostic workfow of pediatric patients with kidney diseases: the experience of a single institution.” Hum Genomics. 2023 Feb 13;17(1):10. doi: 10.1186/s40246- 023-00456-w
