The Laboratory of Molecular Immunology and Oncology was founded in 2007 and is part of the Human Anatomy Section of the Department of Experimental Medicine, University of Genoa. The main field of research is the biology and pathogenesis of B cell Chronic Lymphocytic Leukemia (B-CLL).
Main ongoing projects
Clusters of three-dimensional BCR models in CLL
Igs expressed in Chronic Lymphocytic Leukemia (CLL) have a restricted diversity and up to 30% of CLL cases use stereotypical B-cell receptors (BCR). The three-dimensional (3D) structures of the BCR antigen binding site (ABS) can be reliably modelled and analysed for similarities by informatics tools. In this way non-obvious structural similarities can be identified among the ABSs of BCRs that are apparently different from the genetic point of view. With this approach we showed that most CLL BCRs can be grouped in a limited number of clusters with similar chemico-physical properties (REF).
We believe that the 3D structure of CLL cell BCR has a biological and clinical significance, according to preliminary data. We are studying whether CLL cells belonging to different 3D BCR clusters display peculiar and specific features in terms of: clinical outcome, gene expression profile (GEP), genetic lesions, Ig signalling competence and sensitivity to drugs that inhibit BCR signalling. Our ultimate goal is 1) a biological and clinical validation of the BCR modelling and clustering algorithm employed to define similarities among CLL BCRs and 2) understanding the biological issues responsible for the clinical prognostic value of 3D BCR clusters.
Role of fatty acid oxidation in CLL
A crucial mechanism for CLL development resides in the multiple cycles of re-activation and subsequent clonal expansion of leukemic cells in lymphoid tissues. Our preliminary studies suggest that, in CLL cells turning to an activated/proliferating state, a metabolic reprogramming occurs that enhances fatty acid (FA) metabolism, making CLL cells more dependent on FA oxidation (FAO) and more sensitive to FAO-inhibitors (FAOI).
We observed that activated/proliferating CLL cells are sensitive to the cytotoxic action of FAOIs, at clinically achievable concentrations, more than quiescent cells are, that FAOI induce apoptosis of proliferating CLL cells through mechanisms involving ROS accumulation and down-regulation of anti-apoptotic Bcl-2 machinery, STAT3 pathway and de-novo FA synthesis, that FAOIs potentiate the cytotoxic activity of CLL standard-of-care therapies and novel approaches that loose effectiveness when CLL cells are activated/proliferating. We are investigating the mechanisms underlying the increased dependence on FAO of proliferating CLL cells and the molecular determinants that dictate sensitivity to FAOI among CLL-associated clinical and molecular markers. We also investigate whether pre-leukemic Monoclonal B-cell Lymphocytosis (MBL) cells are sensitive to FAOIs determining a possible CLL-preventive activity.
Altogether, we propose that impairment of FAO by specific inhibitory drugs interferes with leukemic cell activation and subsequent proliferation, lowers proliferation-associated chemoresistance thus increasing drug effectiveness with a consequent decrease of treatment-derived morbidity, and may provide a preventive tool in persons at high-risk of developing CLL. The results may be exploited for designing synergistic therapeutic intervention strategies for high-risk patients.
CLL and bone erosion
In collaboration with the Unit of Nuclear Medicine (GM Sambuceti, Policlinico Ospedale San Martino, Genova) we reported compact bone volume loss in CLL patients as a strong/independent prognostic marker (doi: 10.1038/s41598-017-12761-1). Bone erosion is particularly evident in long bone shafts, progressively increased from Binet stage A to Binet stage C, and correlates with both local expansion of metabolically active bone marrow documented by FDG uptake and with the number of RANKL + cells present in the circulating blood. In immune-deficient NOD/Shi-scid, γcnull (NSG) mice, administration of CLL cells causes an appreciable compact bone erosion that is prevented by Denosumab (doi: 10.1038/s41598-017-12761-1). CLL cell proliferation in vitro correlates with RANK expression and is impaired by Denosumab-mediated disruption of the RANK/RANKL loop (doi: 10.1038/s41598-017-12761-1). Our studies aim at further characterizing the interaction between CLL cells and stromal elements able to simultaneously impair bone structure and increase proliferating potential of leukemic clone. The principal aim is the detailed characterization of the role of RANK/RANKL/OP/OPG axis for leukemic cells survival/proliferation in bone marrow micro-environment and the definition of the effects elicited by interfering with it.
Second, we aim at disclosing the role of CLL cells in bone resorption.
Novel pathway for monosaccharide degradation
We are collaborating with the groups of G.M. Sambuceti and S. Ravera (Depts. Of Health Sciences and Biochemistry, respectively, Genoa University) in the characterization of a novel monosaccharide metabolism and extra-mitochondrial oxidative phosphorylation (OXPHOS). According to all biochemistry textbooks, OXPHOS only occurs in the mitochondrion. Nevertheless, according to our experiments, respiratory proteins have been repeatedly found in non-mitochondrial membranes. Similarly, a competent OXPHOS has been detected in mitochondrion-free structures and in isolated microsomes as samples of the endoplasmic reticulum (ER) (doi: 10.1038/srep25092). Coherently with these observations, silencing the ER enzyme hexose-6P-dehydrogenase (H6PD) impaired ATP content of cancer cells without affecting mitochondrial OXPHOS potential (doi: 10.1038/srep25092). Based on this background, our objective is to test the hypothesis that ER of living cells holds an OXPHOS activity and that the role of mitochondrion, with its genomic cargo, extends beyond the power plant function to the export of OXPHOS proteins empowering other cellular components with the capability to locally adapt energy production.