Treatment Options for Paediatric Anaplastic Large Cell Lymphoma (ALCL): Current Standard and beyond.

Anaplastic Lymphoma Kinase (ALK)-positive Anaplastic Large Cell Lymphoma (ALCL), remains one of the most curable cancers in the paediatric setting; multi-agent chemotherapy cures approximately 65-90% of patients. Over the last two decades, major efforts have focused on improving the survival rate by intensification of combination chemotherapy regimens and employing stem cell transplantation for chemotherapy-resistant patients. More recently, several new and 'renewed' agents have offered the opportunity for a change in the paradigm for the management of both chemo-sensitive and chemo-resistant forms of ALCL. The development of ALK inhibitors following the identification of the EML4-ALK fusion gene in Non-Small Cell Lung Cancer (NSCLC) has opened new possibilities for ALK-positive ALCL. The uniform expression of CD30 on the cell surface of ALCL has given the opportunity for anti-CD30 antibody therapy. The re-evaluation of vinblastine, which has shown remarkable activity as a single agent even in the face of relapsed disease, has led to the consideration of a revised approach to frontline therapy. The advent of immune therapies such as checkpoint inhibition has provided another option for the treatment of ALCL. In fact, the number of potential new agents now presents a real challenge to the clinical community that must prioritise those thought to offer the most promise for the future. In this review, we will focus on the current status of paediatric ALCL therapy, explore how new and 'renewed' agents are re-shaping the therapeutic landscape for ALCL, and identify the strategies being employed in the next generation of clinical trials

Super-enhancer-based identification of a BATF3/IL-2R-module reveals vulnerabilities in anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL), an aggressive CD30-positive T-cell lymphoma, comprises systemic anaplastic lymphoma kinase (ALK)-positive, and ALK-negative, primary cutaneous and breast implant-associated ALCL. Prognosis of some ALCL subgroups is still unsatisfactory, and already in second line effective treatment options are lacking. To identify genes defining ALCL cell state and dependencies, we here characterize super-enhancer regions by genome-wide H3K27ac ChIP-seq. In addition to known ALCL key regulators, the AP-1-member BATF3 and IL-2 receptor (IL2R)-components are among the top hits. Specific and high-level IL2R expression in ALCL correlates with BATF3 expression. Confirming a regulatory link, IL-2R-expression decreases following BATF3 knockout, and BATF3 is recruited to IL2R regulatory regions. Functionally, IL-2, IL-15 and Neo-2/15, a hyper-stable IL-2/IL-15 mimic, accelerate ALCL growth and activate STAT1, STAT5 and ERK1/2. In line, strong IL-2Rα-expression in ALCL patients is linked to more aggressive clinical presentation. Finally, an IL-2Rα-targeting antibody-drug conjugate efficiently kills ALCL cells in vitro and in vivo. Our results highlight the importance of the BATF3/IL-2R-module for ALCL biology and identify IL-2Rα-targeting as a promising treatment strategy for ALCL

Patient-derived xenograft models of ALK+ ALCL reveal preclinical promise for therapy with brigatinib

Anaplastic large-cell lymphoma (ALCL) is a T-cell malignancy predominantly driven by the oncogenic anaplastic lymphoma kinase (ALK), accounting for approximately 15% of all paediatric non-Hodgkin lymphoma. Patients with central nervous system (CNS) relapse are particularly difficult to treat with a 3-year overall survival of 49% and a median survival of 23.5 months. The second-generation ALK inhibitor brigatinib shows superior penetration of the blood–brain barrier unlike the first-generation drug crizotinib and has shown promising results in ALK+ non-small-cell lung cancer. However, the benefits of brigatinib in treating aggressive paediatric ALK+ ALCL are largely unknown. We established a patient-derived xenograft (PDX) resource from ALK+ ALCL patients at or before CNS relapse serving as models to facilitate the development of future therapies. We show in vivo that brigatinib is effective in inducing the remission of PDX models of crizotinib-resistant (ALK C1156Y, TP53 loss) ALCL and furthermore that it is superior to crizotinib as a second-line approach to the treatment of a standard chemotherapy relapsed/refractory ALCL PDX pointing to brigatinib as a future therapeutic option.</p

STAT3 and TP53 mutations associate with poor prognosis in anaplastic large cell lymphoma

Funder: European Union’s Horizon 2020 Marie Skłodowska – Curie Innovative Training Networks (ITN - ETN) under grant agreement No.: 675712European Union’s Horizon 2020 Marie Skłodowska – Curie Innovative Training Networks (ITN - ETN) under grant agreement No.: 675712 Czech Science Foundation (GA CR), junior project no. 19-23424Y MEYS CZ project CEITEC 2020 (LQ1601)Funder: MEYS CZ project CEITEC 2020 (LQ1601) NCMG research infrastructure (LM22018132 funded by MEYS CR)Funder: European Union’s Horizon 2020 Marie Skłodowska – Curie Innovative Training Networks (ITN - ETN) under grant agreement No.: 675712.Funder: MH CZ-RVO 6526970

Super-enhancer-based identification of a BATF3/IL-2R-module reveals vulnerabilities in anaplastic large cell lymphoma.

Anaplastic large cell lymphoma (ALCL), an aggressive CD30-positive T-cell lymphoma, comprises systemic anaplastic lymphoma kinase (ALK)-positive, and ALK-negative, primary cutaneous and breast implant-associated ALCL. Prognosis of some ALCL subgroups is still unsatisfactory, and already in second line effective treatment options are lacking. To identify genes defining ALCL cell state and dependencies, we here characterize super-enhancer regions by genome-wide H3K27ac ChIP-seq. In addition to known ALCL key regulators, the AP-1-member BATF3 and IL-2 receptor (IL2R)-components are among the top hits. Specific and high-level IL2R expression in ALCL correlates with BATF3 expression. Confirming a regulatory link, IL-2R-expression decreases following BATF3 knockout, and BATF3 is recruited to IL2R regulatory regions. Functionally, IL-2, IL-15 and Neo-2/15, a hyper-stable IL-2/IL-15 mimic, accelerate ALCL growth and activate STAT1, STAT5 and ERK1/2. In line, strong IL-2Rα-expression in ALCL patients is linked to more aggressive clinical presentation. Finally, an IL-2Rα-targeting antibody-drug conjugate efficiently kills ALCL cells in vitro and in vivo. Our results highlight the importance of the BATF3/IL-2R-module for ALCL biology and identify IL-2Rα-targeting as a promising treatment strategy for ALCL

The targetable kinase PIM1 drives ALK inhibitor resistance in high-risk neuroblastoma independent of MYCN status

Abstract: Resistance to anaplastic lymphoma kinase (ALK)-targeted therapy in ALK-positive non-small cell lung cancer has been reported, with the majority of acquired resistance mechanisms relying on bypass signaling. To proactively identify resistance mechanisms in ALK-positive neuroblastoma (NB), we herein employ genome-wide CRISPR activation screens of NB cell lines treated with brigatinib or ceritinib, identifying PIM1 as a putative resistance gene, whose high expression is associated with high-risk disease and poor survival. Knockdown of PIM1 sensitizes cells of differing MYCN status to ALK inhibitors, and in patient-derived xenografts of high-risk NB harboring ALK mutations, the combination of the ALK inhibitor ceritinib and PIM1 inhibitor AZD1208 shows significantly enhanced anti-tumor efficacy relative to single agents. These data confirm that PIM1 overexpression decreases sensitivity to ALK inhibitors in NB, and suggests that combined front-line inhibition of ALK and PIM1 is a viable strategy for the treatment of ALK-positive NB independent of MYCN status

ALK in the pathogenesis of cancer

Anaplastic Lymphoma Kinase (ALK) has been implicated in the pathogenesis of many types of cancer including Anaplastic Large Cell Lymphoma (ALCL) and neuroblastoma (NB). ALK is an ideal drug target as its endogenous expression is limited to neuronal cells during neonatal development, although resistance to ALK-targeted therapy has been observed. In this thesis I explore potential mechanisms of resistance to the ALK inhibitors that have been approved for ALK+ non-small cell lung cancer (NSCLC) including crizotinib, alectinib, ceritinib, brigatinib and lorlatinib. To define a global landscape of resistance mechanisms, patient-centric studies require many pre- and post-treatment tumour specimens taken from a sufficient number of patients, which is not possible for a rare cancer such as ALK+ ALCL or ALK driven NB. Hence, genome-wide CRISPR overexpression screens were conducted in ALCL and NB cell lines. We show that resistance to ALK inhibition by crizotinib in ALCL can be driven by aberrant upregulation of interleukin-10 receptor alpha (IL10RA). Elevated IL10RA expression rewires the STAT3 signalling pathway bypassing otherwise critical phosphorylation of STAT3 by NPM1-ALK. IL-10RA expression does not correlate with response to standard chemotherapy in paediatric patients suggesting that a combination of crizotinib with chemotherapy could prevent ALK-inhibitor resistance-specific relapse. In the case of ALK-driven NB resistance to ALK inhibition is associated with expression of the serine/threonine-protein kinase PIM1. While both ALK-driven and ALK-negative NB cells were insensitive to several small-molecule pan-PIM kinase inhibitors, knockdown of PIM1 by RNA interference sensitized cells to ALK inhibition and the combination of ALK inhibitors with the PIM1 inhibitor AZD1208 demonstrated mild synergy. Therefore, our data suggest the potential for combined pharmacological inhibition of ALK and PIM1 in patients with ALK-driven NB. Finally, given the above investigations largely focused on cell line-based models whereby in vitro culture conditions may cause rapid phenotypic and genotypic divergence of patient-derived cells from the originating tumour, we developed two paediatric ALK+ ALCL patient-derived xenograft (PDX) models from liquid biopsy samples of chemotherapy-refractory and crizotinib resistant patients. In vivo investigation showed that second generation ALK inhibitor brigatinib led to a reduction in the mean tumour volume relative to either vehicle or crizotinib treatment. This suggests brigatinib as a treatment option for crizotinib resistant ALCL patients. In summary, this study has identified potential mechanisms of ALK inhibitor resistance particularly in NPM1-ALK positive ALCL and ALK-driven NB.This project has received funding from the European Union’s Horizon 2020 Marie Skłodowska-Curie Innovative Training Networks (ITN-ETN) under grant agreement No.: 67571

Structure and decoy-mediated inhibition of the SOX18/Prox1-DNA interaction

The transcription factor (TF) SOX18 drives lymphatic vessel development in both embryogenesis and tumour-induced neo-lymphangiogenesis. Genetic disruption of Sox18 in a mouse model protects from tumour metastasis and established the SOX18 protein as a molecular target. Here, we report the crystal structure of the SOX18 DNA binding high-mobility group (HMG) box bound to a DNA element regulating Prox1 transcription. The crystals diffracted to 1.75 angstrom presenting the highest resolution structure of a SOX/DNA complex presently available revealing water structure, structural adjustments at the DNA contact interface and non-canonical conformations of the DNA backbone. To explore alternatives to challenging small molecule approaches for targeting the DNA-binding activity of SOX18, we designed a set of five decoys based on modified Prox1-DNA. Four decoys potently inhibited DNA binding of SOX18 in vitro and did not interact with non-SOX TFs. Serum stability, nuclease resistance and thermal denaturation assays demonstrated that a decoy circularized with a hexaethylene glycol linker and terminal phosphorothioate modifications is most stable. This SOX decoy also interfered with the expression of a luciferase reporter under control of a SOX18-dependent VCAM1 promoter in COS7 cells. Collectively, we propose SOX decoys as potential strategy for inhibiting SOX18 activity to disrupt tumour-induced neo-lymphangiogenesis

IL10RA modulates crizotinib sensitivity in NPM1-ALK-positive anaplastic large cell lymphoma

Anaplastic Large Cell Lymphoma (ALCL) is a T-cell malignancy predominantly driven by a hyperactive Anaplastic Lymphoma Kinase (ALK) fusion protein. ALK inhibitors such as crizotinib provide alternatives to standard chemotherapy with reduced toxicity and side effects. Children with lymphomas driven by NPM1-ALK fusion proteins achieved an objective response rate to ALK inhibition therapy of 54-90% in clinical trials. However, a subset of patients progress within the first 3 months of treatment. The mechanism for the development of ALK inhibitor resistance is unknown. Through genome-wide CRISPR activation and knockout screens in ALCL cell lines combined with RNA-seq data derived from ALK inhibitor relapsed patient tumors, we show that resistance to ALK inhibition by crizotinib in ALCL can be driven by aberrant upregulation of IL10RA. Elevated IL10RA expression rewires the STAT3 signaling pathway bypassing otherwise critical phosphorylation by NPM1-ALK. IL10RA expression does not correlate with response to standard chemotherapy in pediatric patients suggesting that combination of crizotinib with chemotherapy could prevent ALK-inhibitor resistance-specific relapse