Tyrosine phosphatases regulate resistance to ALK inhibitors in ALK+ anaplastic large cell lymphoma

Anaplastic large cell lymphomas (ALCLs) frequently carry oncogenic fusions involving the anaplastic lymphoma kinase (ALK) gene. Targeting ALK using tyrosine kinase inhibitors (TKIs) is a therapeutic option in cases relapsed after chemotherapy, but TKI resistance may develop. By applying genomic loss-of-function screens, we identified PTPN1 and PTPN2 phosphatases as consistent top hits driving resistance to ALK TKIs in ALK+ ALCL. Loss of either PTPN1 or PTPN2 induced resistance to ALK TKIs in vitro and in vivo. Mechanistically, we demonstrated that PTPN1 and PTPN2 are phosphatases that bind to and regulate ALK phosphorylation and activity. In turn, oncogenic ALK and STAT3 repress PTPN1 transcription. We found that PTPN1 is also a phosphatase for SHP2, a key mediator of oncogenic ALK signaling. Downstream signaling analysis showed that deletion of PTPN1 or PTPN2 induces resistance to crizotinib by hyperactivating SHP2, the MAPK, and JAK/STAT pathways. RNA sequencing of patient samples that developed resistance to ALK TKIs showed downregulation of PTPN1 and PTPN2 associated with upregulation of SHP2 expression. Combination of crizotinib with a SHP2 inhibitor synergistically inhibited the growth of wild-type or PTPN1/PTPN2 knock-out ALCL, where it reverted TKI resistance. Thus, we identified PTPN1 and PTPN2 as ALK phosphatases that control sensitivity to ALK TKIs in ALCL and demonstrated that a combined blockade of SHP2 potentiates the efficacy of ALK inhibition in TKI-sensitive and -resistant ALK+ ALCL. READ ARTICLE

Blood DOI:10.1182/blood.2020008136

Authors: Karaca Atabay E, Mecca C, Wang Q, Ambrogio C, Mota I, Prokoph N, Mura G, Martinengo C, Patrucco E, Leonardi G, Hossa J, Pich A, Mologni L, Gambacorti-Passerini C, Brugières L, Geoerger B, Turner SD, Voena C, Cheong TC, Chiarle R.

Phase-separated foci of EML4-ALK facilitate signalling and depend upon an active kinase conformation

Variants of the oncogenic EML4-ALK fusion protein contain a similar region of ALK encompassing the kinase domain, but different portions of EML4. Here, we show that EML4-ALK V1 and V3 proteins form cytoplasmic foci that contain components of the MAPK, PLCγ and PI3K signalling pathways. The ALK inhibitors ceritinib and lorlatinib dissolve these foci and EML4-ALK V3 but not V1 protein re-localises to microtubules, an effect recapitulated in a catalytically inactive EML4-ALK mutant. Mutations that promote a constitutively active ALK stabilise the cytoplasmic foci even in the presence of these inhibitors. In contrast, the inhibitor alectinib increases foci formation of both wild-type and catalytically inactive EML4-ALK V3 proteins, but not a Lys-Glu salt bridge mutant. We propose that EML4-ALK foci formation occurs as a result of transient association of stable EML4-ALK trimers mediated through an active conformation of the ALK kinase domain. Our results demonstrate the formation of EML4-A..... READ ARTICLE

EMBO Reports DOI:10.15252/embr.202153693

Authors: Josephina Sampson, Mark W Richards, Jene Choi, Andrew M Fry, Richard Bayliss

Pre-Clinical, group2Kirk SmithOctober 18, 2021EML4-ALK fusion protein, variants, inhibitors, cytoplasmic foci

Outcomes of first, second, and third-generation anaplastic lymphoma kinase (ALK) inhibitors in non-small cell lung cancer brain metastases (NSCLCBM)

Background: Non-small cell lung cancer (NSCLC) is the most common cause of brain metastases. ALK, which codes for tyrosine kinase receptors, is rearranged in 4-7% of NSCLC. First-generation ALK inhibitors have restricted efficacy due to poor blood-brain barrier (BBB) penetration and ALK-resistant tumor mutations. Second-generation ALK inhibitors have shown better BBB penetration, while third-generation ALK inhibitors were efficacious even against ALK-resistant mutations. In this retrospective study, we investigated the overall survival (OS) and progression-free survival (PFS) in NSCLCBM patients treated with first, second, and third-generation ALK inhibitors. Conclusions: Newer generations of targeted therapies in NSCLCBM have improved BBB penetration and effectiveness against resistant mutations. We determined that there was a significant 5-year OS benefit in patients who received second and third-generation ALK inhibitors compared to first-generation ALK inhibitors, and a respective..... READ ARTICLE

Journal of Clinical Oncology DOI:10.1200/JCO.2021.39.15_suppl.2034

Authors: Vineeth Tatineni, Patrick Joseph O'Shea, Yasmeen Rauf, Xuefei Jia, Erin Sennett Murphy, Samuel T. Chao, John H. Suh, David M. Peereboom, Manmeet Singh Ahluwalia

A Novel Nonreciprocal/Reciprocal ALK Translocation Cause ALK+ in NSCLC

The development and clinical application of ALK inhibitors have made a great breakthrough in recent years. It is of great clinical significance to identify the target population suitable for ALK inhibitors by using appropriate ALK detection methods. 5’ALK fusions currently draw the most attention. Nonreciprocal/reciprocal ALK translocations were often thought of nonfunctional or neglected. Here, we identified a rare patient with lung adenocarcinoma in pT1N2M0 stage IIIA. Tumor tissue of the patient harbored a novel nonreciprocal/reciprocal ALK translocation which did not form a 5’ALK fusion. But Tumor tissue did express ALK protein, which is normally not expressed in the lungs. READ ARTICLE

Lung Cancer DOI: 10.1016/j.lungcan.2021.05.020

Authors: Xianguo Chen, Bo Xu, Fangni Fu, Ke Cai and Zhaonan Yu

Case StudyKirk SmithMay 20, 2021ALK, Nonreciprocal/reciprocal Translocation, NSCLC, inhibitors

SPECC1L-ALK: A novel gene fusion response to ALK inhibitors in non-small cell lung cancer

There was a case report showed that a novel pleckstrin homology and RUN domain containing M2 (PLEKHM2)- anaplastic lymphoma kinase (ALK) gene rearrangement in small cell lung cancer (SCLC) patient had long-term benefit from ALK inhibitors [ [1] ]. Actually, the case report demonstrated that next generation sequence (NGS) maybe a very useful method for detecting a new subtype of ALK fusion and it may provide a better understanding of ALK- tyrosine kinase inhibitors (TKIs) treatment. Here, we identified a novel type of ALK rearrangement responding to ALK inhibitors in non-small cell lung cancer (NSCLC) by NGS. READ ARTICLE

Lung Cancer DOI:10.1016/j.lungcan.2020.03.017

Authors: Li Ma, Quan Zhang, Yujie Dong, Haoyang Li, Jinghui Wang

Case StudyKirk SmithMay 1, 2020SPECC1L-ALK, gene fusion, ALK, inhibitors, non-small cell lung cancer