Mechanisms of ALK-mediated transformation and drug resistance to therapy in ALK-driven tumors

By exploiting different in vitro (2D and 3D cell lines, and patient-derived organoids- PDO), and in vivo models (patient-derived xenograft -PDX and mouse models for ALCL and NSCLC), our research aims at defining relevant mechanisms of transformation in ALK-positive tumors to find new therapeutic vulnerabilities and to validate innovative treatments (FIGURE 3). 

Proper cytoskeletal regulation is fundamental in lymphoid cells for almost any aspect of T-cell biology, and small GTPases (Ras and Rho-family GTPases) are among the major players in this regulation. We are investigating the role of the RHO GTPases in lymphomagenesis, specifically in anaplastic large cell lymphomas (ALK+ and ALK- ALCL). Using in vitro and in vivo models we will study how RHOA impacts the biology of lymphoma cells. RHO GTPases are key biological regulators of both ALK+ and ALK- ALCL therefore they can represent novel targetable vulnerabilities that can be exploited in the treatment of ALCL alone or in combination with other existing treatments. In addition, our findings can potentially highlight therapeutic targets for other type of T cell lymphoma. Targeted therapy has changed the clinical outcome of ALK+ patients. However, the development of resistance is inevitable. There is still limited understanding on how acquired resistance develops and undermines the effects of ALK TKIs. In addition, it is now clear that the heterogeneity of cancer cells is associated with resistance and that the presence of sub-population of drug-tolerant cells (called persister cells) can play a major role in resistance. We have recently demonstrated that CCL19/21-CCR7-PI3Kg axis drives resistance to ALK tyrosine kinase inhibitors (TKIs) and promotes survival of ALK+ ALCL persister cells in the perivascular niche during TKI treatment. We are then working on the hypothesis that the concomitant blockade of PI3Kg and/or the CCR7 receptor during ALK TKI treatment would contribute to reduce primary resistance as well as the survival of residual lymphoma cells. We will use 3D microvessel cell culture system that mimic the lymphoma perivascular niche and sub cutis or intravenous grafs of ALK+ ALCL cell lines and ALK+ ALCL patient derived xenografs (ALCL-PDX). In ALK+ lung cancer, there is unmet medical need for ALK+ NSCLC patients with co-occurring TP53 mutations, which account for about 25% of ALK-positive NSCLC patients, as these patients sufer from unfavorable outcome treated either with ALK-inhibitors or conventional chemotherapy. Recently, the selective inhibitors of nuclear export (SINEs) represent a promising therapy in single or in combination with standard therapies. We previously demonstrated that treatment of ALK+ ALCL cells with SINE together with the ALK-inhibitor crizotinib exerts a pronounced synergistic activity on cell viability and survival of lymphoma cells. Based on these data, we are now investigating the eficacy of SINEs as single agents and in combination with ALK-inhibitors in ALK TKI-sensitive and resistant ALK+ lung cancer cell lines and in ALK TKI-resistant patient-derived organoids (PDOs). In addition, we are also looking for novel mechanisms of resistance to ALK TKI treatment in ALK-driven tumors. To discover these mechanisms, we will use high throughput screening techniques such as whole genome sequencing (WES), RNA-sequencing, sc-RNA sequencing and proteomics and we will develop murine models along with more innovative 3D models to study the biology of these mechanisms.