ALK Signaling Research Articles

Identification of the Wallenda JNKKK as an Alk suppressor reveals increased competitiveness of Alk-expressing cells

Anaplastic lymphoma kinase (Alk) is a receptor tyrosine kinase of the insulin receptor super-family that functions as oncogenic driver in a range of human cancers such as neuroblastoma. In order to investigate mechanisms underlying Alk oncogenic signaling, we conducted a genetic suppressor screen in Drosophila melanogaster. Our screen identified multiple loci important for Alk signaling, including members of Ras/Raf/ERK-, Pi3K-, and STAT-pathways as well as tailless (tll) and foxo whose orthologues NR2E1/TLX and FOXO3 are transcription factors implicated in human neuroblastoma. Many of the identified suppressors were also able to modulate signaling output from activated oncogenic variants of human ALK, suggesting that our screen identified targets likely relevant in a wide range of contexts. Interestingly, two misexpression alleles of wallenda (wnd, encoding a leucine zipper bearing kinase similar to human DLK and LZK) were among the strongest suppressors. We show that Alk expression leads to a growth advantage and induces cell death in surrounding cells. Our results suggest that Alk activity conveys a competitive advantage to cells, which can be reversed by over-expression of the JNK kinase kinase Wnd.

Inhibition of Alk signaling promotes the induction of human salivary-gland-derived organoids.

ABSTRACTHyposalivation and xerostomia are the cause of several morbidities, such as dental caries, painful mucositis, oral fungal infections, sialadenitis and dysphagia. For these reasons, preservation of normal saliva secretion is critical for the maintenance of functionally normal oral homeostasis and for keeping good health. Several strategies for restoring salivary gland function have been reported, from different points of view, based on the use of salivary-gland-derived epithelial stem/progenitor cells and tissue engineering approaches to induce organoids that mimic in vivo salivary glands. In this study, we clarified that inhibition of activin receptor-like kinase (Alk) signaling was essential for the induction of human salivary-gland-derived organoids, and demonstrated the usefulness of such organoids as an inflammatory disease model. In inflammatory conditions like sialadenitis, in general, pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α, also known as TNF) are upregulated, but their function is still unclear. In our established human salivary-gland-derived organoid culture system, we successfully induced organoid swelling by stimulation with carbachol, a non-selective cholinergic agonist, and forskolin, an activator of cystic fibrosis transmembrane conductance regulator (CFTR). Furthermore, we found that this organoid swelling was inhibited by TNF-α. From these results, we could clarify the inhibitory function of TNF-α on saliva secretion in vitro. Thus, our established human salivary-gland-derived organoids would be useful for in vitro analyses of the morphological and functional changes involved in salivary gland dysfunctions in several research fields, such as pathobiology, inflammation and regenerative medicine.This article has an associated First Person interview with the first author of the paper.

First person – Shohei Yoshimoto

ABSTRACTFirst Person is a series of interviews with the first authors of a selection of papers published in Disease Models & Mechanisms, helping early-career researchers promote themselves alongside their papers. Shohei Yoshimoto is first author on ‘Inhibition of Alk signaling promotes the induction of human salivary-gland-derived organoids’, published in DMM. Shohei is a research scientist in the lab of Professor Shuichi Hashimoto at Fukuoka Dental College, Fukuoka, Japan, investigating salivary gland disorders.

The neuronal receptor tyrosine kinase Alk is a target for longevity.

Inhibition of signalling through several receptor tyrosine kinases (RTKs), including the insulin‐like growth factor receptor and its orthologues, extends healthy lifespan in organisms from diverse evolutionary taxa. This raises the possibility that other RTKs, including those already well studied for their roles in cancer and developmental biology, could be promising targets for extending healthy lifespan. Here, we focus on anaplastic lymphoma kinase (Alk), an RTK with established roles in nervous system development and in multiple cancers, but whose effects on aging remain unclear. We find that several means of reducing Alk signalling, including mutation of its ligand jelly belly (jeb), RNAi knock‐down of Alk, or expression of dominant‐negative Alk in adult neurons, can extend healthy lifespan in female, but not male, Drosophila. Moreover, reduced Alk signalling preserves neuromuscular function with age, promotes resistance to starvation and xenobiotic stress, and improves night sleep consolidation. We find further that inhibition of Alk signalling in adult neurons modulates the expression of several insulin‐like peptides, providing a potential mechanistic link between neuronal Alk signalling and organism‐wide insulin‐like signalling. Finally, we show that TAE‐684, a small molecule inhibitor of Alk, can extend healthy lifespan in Drosophila, suggesting that the repurposing of Alk inhibitors may be a promising direction for strategies to promote healthy aging.

Abstract 3806: Overcoming drug-tolerant cancer cell subpopulations showing AXL activation and epithelial-mesenchymal transition is critical in conquering ALK-positive lung cancer

Abstract Anaplastic lymphoma kinase tyrosine kinase inhibitors (ALK-TKIs) induce a dramatic response in non-small cell lung cancer (NSCLC) patients with the ALK fusion gene. However, acquired resistance to ALK-TKIs remains an inevitable problem. In this study, we aimed to discover novel therapeutic targets to conquer ALK-positive lung cancer. We established three types of ALK-TKI (crizotinib, alectinib and ceritinib) -resistant H2228 NSCLC cell lines by high exposure and stepwise methods. We found these cells showed a loss of ALK signaling, overexpressed AXL with epithelial-mesenchymal transition (EMT), and had cancer stem cell-like (CSC) properties, suggesting drug-tolerant cancer cell subpopulations. Similarly, we demonstrated that TGF-β1 treated H2228 cells also showed AXL overexpression with EMT features and ALK-TKI resistance. The AXL inhibitor, R428, or HSP90 inhibitor, ganetespib, were effective in reversing ALK-TKI resistance and EMT changes in both ALK-TKI-resistant and TGF-β1-exposed H2228 cells. Tumor volumes of xenograft mice implanted with established H2228-ceritinib-resistant (H2228-CER) cells were significantly reduced after treatment with ganetespib, or ganetespib in combination with ceritinib. Some ALK-positive NSCLC patients with AXL overexpression showed a poorer response to crizotinib therapy than patients with a low expression of AXL. ALK signaling-independent AXL overexpressed in drug-tolerant cancer cell subpopulations with EMT and CSC features may be commonly involved commonly involved in intrinsic and acquired resistance to ALK-TKIs. This suggests AXL and HSP90 inhibitors may be promising therapeutic drugs to overcome drug-tolerant cancer cell subpopulations in ALK-positive NSCLC patients for the reason that ALK-positive NSCLC cells do not live through ALK-TKI therapy. Citation Format: Shinji Nakamichi, Seike Masahiro, Akihiko Miyanaga, Akiko Takahashi, Rintaro Noro, Kaoru Kubota, Akihiko Gemma. Overcoming drug-tolerant cancer cell subpopulations showing AXL activation and epithelial-mesenchymal transition is critical in conquering ALK-positive lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3806.

Genome-wide screening identifies oncofetal lncRNA Ptn-dt promoting the proliferation of hepatocellular carcinoma cells by regulating the Ptn receptor

Oncofetal genes are genes that express abundantly in both fetal and tumor tissues yet downregulated or undetected in adult tissues, and can be used as tumor markers for cancer diagnosis and treatment. Meanwhile, long noncoding RNAs (lncRNAs) are known to play crucial roles in the pathogenesis of hepatocellular carcinoma (HCC), including tumor growth, proliferation, metastasis, invasion, and recurrence. We performed a genome-wide screening using microarrays to detect the lncRNA expression profiles in fetal livers, adult livers, and liver cancer tissues from mice to identify oncofetal lncRNAs in HCC. From the microarray data analysis, we identified lncRNA Ptn-dt as a possible oncofetal gene. Both in vitro and in vivo experiments results confirmed that overexpression of Ptn-dt significantly promoted the proliferation of mouse HCC cells. RNA pulldown assay showed that Ptn-dt could interact with the HuR protein. Interestingly, miR-96 binds with HuR to maintain its stability as well. Overexpression of lncRNA Ptn-dt led to the downregulation of miR-96, which might be due to the interaction between Ptn-dt and HuR. Meanwhile, previous studies have reported that Ptn can promote tumor growth and vascular abnormalization via anaplastic lymphoma kinase (Alk) signaling. In our study, we found that overexpression of Ptn-dt could promote the expression of Alk through repressing miR-96 via interacting with HuR, thus enhancing the biologic function of Ptn. In summary, a new oncofetal lncRNA Ptn-dt is identified, and it can promote the proliferation of HCC cells by regulating the HuR/miR-96/Alk pathway and Ptn-Alk axis.

ALK positively regulates MYCN activity through repression of HBP1 expression.

ALK mutations occur in 10% of primary neuroblastomas and represent a major target for precision treatment. In combination with MYCN amplification, ALK mutations infer an ultra-high-risk phenotype resulting in very poor patient prognosis. To open up opportunities for future precision drugging, a deeper understanding of the molecular consequences of constitutive ALK signaling and its relationship to MYCN activity in this aggressive pediatric tumor entity will be essential. We show that mutant ALK downregulates the 'HMG-box transcription factor 1' (HBP1) through the PI3K-AKT-FOXO3a signaling axis. HBP1 inhibits both the transcriptional activating and repressing activity of MYCN, the latter being mediated through PRC2 activity. HBP1 itself is under negative control of MYCN through miR-17~92. Combined targeting of HBP1 by PI3K antagonists and MYCN signaling by BET- or HDAC-inhibitors blocks MYCN activity and significantly reduces tumor growth, suggesting a novel targeted therapy option for high-risk neuroblastoma.

Concomitant resistance mechanisms to multiple tyrosine kinase inhibitors in ALK-positive non-small cell lung cancer

ObjectivesALK tyrosine kinase inhibitors (TKIs), including crizotinib and several next generation TKIs, have demonstrated beneficial clinical outcomes in ALK-positive non-small cell lung cancer (NSCLC). However, resistance mechanisms following multiple TKI treatments in ALK-positive NSCLC are not fully elucidated. Materials and methodsMutation profiles of 422 cancer-relevant genes in 52 patients with post-TKI biopsy samples were analyzed using next-generation sequencing (NGS), and compared between patients receiving crizotinib alone (n = 35) and multi-TKIs (n = 17). ResultsEML4-ALK variant 3 is the most frequent ALK variants in this cohort, followed by EML4-ALK variant 1. Half of the patients harbored ALK activating mutations upon progression on crizotinib treatment. After multi-TKIs treatment, 59% of the cases developed resistant ALK mutations, and concomitant ALK activating mutations were more commonly observed in this cohort (P = 0.031). Specifically, ALK G1269 A, L1196 M, and C1156Y substitutions were more common in crizotinib-alone samples, while ALK G1202R was significantly more enriched post-multi-TKIs (P = 0.009). Activated bypass signaling tended to be more prevalent in patients post-multi-TKIs. Furthermore, dual activation of ALK and bypass signaling was more frequently found in the multi-TKIs group (5/17, 29%) in contrast to crizotinib-alone (2/35, 6%) (P = 0.031). Additionally, concurrent TP53 mutation demonstrated significantly shorter progression-free survival (PFS) compared with TP53 wildtype in crizotinib-alone group (median PFS: 8 vs 13 months, Hazard Ratio = 1.494, P = 0.019). ConclusionConcurrent ALK activating mutations and/or upregulated bypass signaling are more enriched in patients undergoing multiple ALK TKI treatments compared to crizotinib alone. Concomitant TP53 mutation correlated to unfavorable survival when receiving a single TKI crizotinib.

Phosphoproteome and gene expression profiling of ALK inhibition in neuroblastoma cell lines reveals conserved oncogenic pathways

Anaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor that is a clinical target of major interest in cancer. Mutations and rearrangements in ALK trigger the activation of the encoded receptor and its downstream signaling pathways. ALK mutations have been identified in both familial and sporadic neuroblastoma cases as well as in 30 to 40% of relapses, which makes ALK a bona fide target in neuroblastoma therapy. Tyrosine kinase inhibitors (TKIs) that target ALK are currently in clinical use for the treatment of patients with ALK-positive non-small cell lung cancer. However, monotherapy with the ALK inhibitor crizotinib has been less encouraging in neuroblastoma patients with ALK alterations, raising the question of whether combinatorial therapy would be more effective. In this study, we established both phosphoproteomic and gene expression profiles of ALK activity in neuroblastoma cells exposed to first- and third-generation ALK TKIs, to identify the underlying molecular mechanisms and identify relevant biomarkers, signaling networks, and new therapeutic targets. This analysis has unveiled various important leads for novel combinatorial treatment strategies for patients with neuroblastoma and an increased understanding of ALK signaling involved in this disease.

TROP-2 exhibits tumor suppressive functions in cervical cancer by dual inhibition of IGF-1R and ALK signaling

ObjectiveInactivation of tumor suppressor genes promotes initiation and progression of cervical cancer. This study aims to investigate the tumor suppressive effects of TROP-2 in cervical cancer cells and to explain the underlying mechanisms. MethodsThe tumor suppressive functions of TROP-2 in cervical cancer cells were examined by in vitro and in vivo tumorigenic functional assays. Downstream factors of TROP-2 were screened using Human Phospho-Receptor Tyrosine Kinase Array. Small molecule inhibitors were applied to HeLa cells to test the TROP-2 effects on the oncogenicity of IGF-1R and ALK. Protein interactions between TROP-2 and the ligands of IGF-1R and ALK were detected via immunoprecipitation assay and protein-protein affinity prediction. ResultsIn vitro and in vivo functional assays showed that overexpression of TROP-2 significantly inhibited the oncogenicity of cervical cancer cells; while knockdown of TROP-2 exhibited opposite effects. Human Phospho-Receptor Tyrosine Kinase Array showed that the activity of IGF-1R and ALK was stimulated by TROP-2 knockdown. Small molecule inhibitors AG1024 targeting IGF-1R and Crizotinib targeting ALK were treated to HeLa cells with and without TROP-2 overexpression, and results from cell viability and migration assays indicated that the oncogenicity of vector-transfected cells was repressed to a greater extent by the inhibition of either IGF-1R or ALK than that of the TROP-2-overexpressed cells. Immunoprecipitation assay and protein-protein affinity prediction suggested protein interactions between TROP-2 and the ligands of IGF-1R and ALK. ConclusionsCollectively, our results support that TROP-2 exhibits tumor suppressor functions in cervical cancer through inhibiting the activity of IGF-1R and ALK.

Neoadjuvant Crizotinib in Resectable Locally Advanced Non–Small Cell Lung Cancer with ALK Rearrangement

BackgroundLocally advanced NSCLC is one of the most heterogeneous conditions, with multidimensional treatments involved. Neoadjuvant therapy had been commonly considered an optimal management strategy for patients with operable locally advanced. However, as targeted therapy has been widely applied in advanced NSCLC, neoadjuvant targeted therapy has remained poorly explored in locally advanced disease. MethodsWe have described 11 ALK receptor tyrosine kinase gene (ALK)-positive patients with pathologically confirmed N2 NSCLC who were treated with neoadjuvant crizotinib. All the patients were treatment naive and received crizotinib at a starting dose of 250 mg twice daily. Patient 3 was provided with dynamic monitoring before and after neoadjuvant therapy through next-generation sequencing of plasma and tissue. In case 4, next-generation sequencing of preoperative tissue was performed. ResultsOf the 11 patients, 10 had a partial response and one was stable disease after neoadjuvant crizotinib, with one suffering from grade 4 hepatic damage. Of the 11 patients, 10 (91.0%) received an R0 resection and 2 patients achieved a pathological complete response to neoadjuvant crizotinib. Six patients had disease recurrence, with five of them receiving crizotinib as first-line treatment and achieving a long duration of response. Dynamic monitoring of both plasma and tissue simultaneously indicated a decrease in sensitive ALK signaling in patient 3 and a partial response (approximately 50% of partial response), and no ALK-dependent resistance variants were captured. ConclusionNeoadjuvant crizotinib may be feasible and well tolerated in locally advanced disease for complete resection. Crizotinib therapy before surgery may provide thorough elimination of circulating molecular residual disease and not influence the reuse of first-line crizotinib, but ongoing prospective trials are warranted to prove its efficacy in the neoadjuvant setting.

P1.13-07 Epithelial-Mesenchymal Transition Induced the Acquired Resistance to ALK Inhibitor Brigatinib in Lung Cancer Cells Harboring with ALK Fusions

The ALK inhibitors, such as crizotinib and alectinib show a great response to patients with non-small cell lung cancer (NSCLC) harboring ALK fusions. However, the acquired drug resistance is also known as important issues in the treatment with the specific molecular targeted agents, such as EGFR-TKI as well as ALK-TKI. The mechanisms of acquired resistance to ALK-TKI are reported previously, bypass tract signals of EGFR or MET, and Epithelial-mesenchymal transition (EMT). Novel generation ALK inhibitor brigatinib is promising for NSCLC harboring ALK fusions, however, the precise mechanism of the acquired resistance to brigatinib is not fully understood. To elucidate for the novel acquired resistance to brigatinib, we here conducted the cell-based experiments using ALK fusion NSCLC cells. We established ALK fusion NSCLC cells H3122 (variant 1 E13;A20) and H2228 (variant 3 E6; A20) with the acquired resistance to brigatinib by step-wise methods. ALK inhibitor sensitivity and signal transduction in H3122 and H2228 cells were examined in vitro. H3122-brigatinib resistance cell (H3122-BR) and H2228-brigatinib resistance cell (H2228-BR) indicated the cross-resistance to other ALK inhibitors alectinib, crizotinib and lorlatinib. Furthermore, morphological change was observed to spindle shape, and additionally shows decreasing of E-cadherin and increasing of vimentin which are marker of EMT by the western blotting analysis. Moreover, some of these resistant cells cultured with drug-free medium for 4weeks were reversed the sensitivity to ALK-TKIs and cell formation backed to parental cells. We demonstrated that EMT elicited the acquired resistance to ALK-TKIs under the exposure of brigatinib treatment in ALK fusion NSCLC cells. Further experiments are needed to overcome this drug resistance induced by EMT.

Abstract 4794: Preclinical evaluation of WX-0593, a potent orally active ALK inhibitor

Abstract Objective: ALK is a tyrosine kinase belonging to the insulin receptor super-family. The constitutively active ALK fusions are oncogenic and linked with multiple types of human cancer. The EML4-ALK fusion has been proven to be the driver of approximately 5% of NSCLC patients. We disclose here for the first time a novel ALK inhibitor WX-0593 and its preclinical evaluation data in preclinical models of ALK driven NSCLC. Method: The enzyme activities of WX-0593 for ALKWT, ALKL1196M, ALKC1156Y and EGFRL858R/T790M were measured with corresponding kinase assays. The anti-proliferative activity was evaluated in Karpas-299, Ba/F3, Ba/F3 (EML4-ALK-WT), Ba/F3 (EML4-ALK-L1196M), Ba/F3 (EML4-ALK-C1156Y), and NCI-H1975 cell lines. The specific effect (PD) of WX-0593 on ALK signaling was analyzed in NCI-H3122 cells. Antitumor activity of WX-0593 was evaluated in three patient-derived xenograft (PDX) models of NSCLC (LU-01-0015, LU-01-0319, and crizotinib resistant LU-01-0319R) and one cell-derived xenograft (CDX) model of NSCLC (NCI-H3122). PKPD was assessed by western blot analysis of the treated tumor tissues for p-ALK (Tyr1604), p-STAT3 (Tyr705), p-STAT5 (Tyr694), p-AKT, and p-ERK. Result: WX-0593 displayed potent enzymatic activities for ALKWT, ALKL1196M, ALKC1156Y and EGFRL858R/T790M with IC50 of 5.38, 9.26, 9.28, and 16.74 nM respectively. It also showed expected anti-proliferative activity in six cell lines, Karpas-299, Ba/F3, Ba/F3 (EML4-ALK-WT), Ba/F3 (EML4- ALK-L1196M), Ba/F3 (EML4-ALK-C1156Y), and NCI-H1975, with IC50 of 4.5, 2208, 4, 9.5, 9, and 508 nM, respectively. Western blot study in NCI-H3122 cells showed that WX-0593 could fully inhibit p-ALK, p-ERK,p-STAT5 at 11.1 nM and p-AKT at 100 nM. WX-0593 significantly inhibited tumor growth at all doses tested (P<0.001) in the LU-01-0015 (HIP1-ALK), LU-01-0319 (EML4-ALK), and LU-01-0319R NSCLC PDX models as well as in the NCI-H3122 CDX model. Western blot analysis of the tumor samples showed that WX-0593 inhibited p-ALK (Tyr1604), p-STAT3 (Tyr705), p-STAT5 (Tyr694), p-AKT, and p-ERK, indicating that the tumor growth inhibition was mediated by inhibition of ALK signaling. Conclusion: We have identified a potent orally active second generation ALK inhibitor, WX-0593. It can inhibit the activity of both wide type and crizotinib resistant ALK and showed strong antitumor activity in in vitro and in vivo preclinical models. These results are considered highly promising and warrant moving the compound forward to clinical investigation. Citation Format: Liu Xile, Charles Z Ding, Weifeng Mao, Yuxin Qin, Shansong Zheng, Yingying Yang, Qingmei Zheng, Long Zhang, Shuyong Zhao. Preclinical evaluation of WX-0593, a potent orally active ALK inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4794.

Overcoming drug-tolerant cancer cell subpopulations showing AXL activation and epithelial-mesenchymal transition is critical in conquering ALK-positive lung cancer.

Anaplastic lymphoma kinase tyrosine kinase inhibitors (ALK-TKIs) induce a dramatic response in non–small cell lung cancer (NSCLC) patients with the ALK fusion gene. However, acquired resistance to ALK-TKIs remains an inevitable problem. In this study, we aimed to discover novel therapeutic targets to conquer ALK-positive lung cancer. We established three types of ALK-TKI (crizotinib, alectinib and ceritinib)-resistant H2228 NSCLC cell lines by high exposure and stepwise methods. We found these cells showed a loss of ALK signaling, overexpressed AXL with epithelial-mesenchymal transition (EMT), and had cancer stem cell-like (CSC) properties, suggesting drug-tolerant cancer cell subpopulations. Similarly, we demonstrated that TGF-β1 treated H2228 cells also showed AXL overexpression with EMT features and ALK-TKI resistance. The AXL inhibitor, R428, or HSP90 inhibitor, ganetespib, were effective in reversing ALK-TKI resistance and EMT changes in both ALK-TKI-resistant and TGF-β1-exposed H2228 cells. Tumor volumes of xenograft mice implanted with established H2228-ceritinib-resistant (H2228-CER) cells were significantly reduced after treatment with ganetespib, or ganetespib in combination with ceritinib. Some ALK-positive NSCLC patients with AXL overexpression showed a poorer response to crizotinib therapy than patients with a low expression of AXL. ALK signaling-independent AXL overexpressed in drug-tolerant cancer cell subpopulations with EMT and CSC features may be commonly involved commonly involved in intrinsic and acquired resistance to ALK-TKIs. This suggests AXL and HSP90 inhibitors may be promising therapeutic drugs to overcome drug-tolerant cancer cell subpopulations in ALK-positive NSCLC patients for the reason that ALK-positive NSCLC cells do not live through ALK-TKI therapy.

Evaluation of a Dual ALK/ROS1 Fluorescent In Situ Hybridization Test in Non–Small-cell Lung Cancer

BackgroundSeveral therapeutics targets have emerged to treat patients with non–small-cell lung carcinoma (NSCLC), with numerous biomarkers available to test for treatment choices. Minimum tumor wastage is necessary to permit the analysis of every potentially relevant target. Searching for targetable ALK and ROS1 rearrangements is now mandatory in NSCLC. In the present study, we evaluated the performance of a dual ALK/ROS1 fluorescent in situ hybridization (FISH) probe that concurrently analyzed the 2 oncogenes on a same FISH slide. Materials and MethodsWe used the FlexISH ALK/ROS1 DistinguISH Probe (Zytovision, Bremerhaven, Germany) to analyze a set of 28 formalin-fixed paraffin-embedded NSCLC tumor samples enriched in tumors with ALK- and ROS1-rearranged status. ResultsThe dual ALK/ROS1 FISH probe test results were fully concordant with the results of previous single ALK and ROS1 FISH tests (15 ALK and 3 ROS1 rearrangements) without any false-positive results. Dual- and single-probe FISH test results were also concordant regarding the unusual ALK FISH patterns. These included 1 sample that had negative FISH results with diffuse single 5′-ALK signals and positive ALK immunohistochemistry findings in a patient with a response to crizotinib, 2 paired samples with high percentages of ALK FISH-rearranged nuclei despite negative ALK immunohistochemistry findings, and ALK FISH-positive samples from 2 patients lacking a response to crizotinib therapy despite concordant ALK FISH and immunohistochemistry-positive results. ConclusionThe dual ALK/ROS1 FISH probe test is a valuable tool to search concurrently for both ALK and ROS1 rearrangements on a same FISH slide and could help to spare tumor tissue for other biomarkers tests.

A subgroup of pleural mesothelioma expresses ALK protein and may be targetable by combined rapamycin and crizotinib therapy.

Malignant pleural mesothelioma (MPM) is a neoplasm with inferior prognosis and notorious chemotherapeutic resistance. Targeting aberrantly overexpressed kinases to cure MPM is a promising therapeutic strategy. Here, we examined ALK, MET and mTOR as potential therapeutic targets and determined the combinatorial efficacy of ALK and mTOR targeting on tumor cell growth in vivo.First, ALK overexpression, rearrangement and mutation were studied in primary MPM by qRT-PCR, FISH, immunohistochemistry and sequence analysis; mTOR and MET expression by qRT-PCR and immunohistochemistry. Overexpression of full-length ALK transcripts was observed in 25 (19.5%) of 128 primary MPM, of which ten expressed ALK protein. ALK overexpression was not associated with gene rearrangement, amplification or kinase-domain mutation. mTOR protein was detected in 28.7% MPM, co-expressed with ALK or MET in 5% and 15% MPM, respectively. The ALK/MET inhibitor crizotinib enhanced the anti-tumor effect of the mTOR-inhibitor rapamycin in a patient-derived MPM xenograft with co-activated ALK/mTOR: combined therapy achieved tumor shrinkage in 4/5 tumors and growth stagnation in one tumor. Treatment effects on proliferation, apoptosis, autophagy and pathway signaling were assessed using Ki-67 immunohistochemistry, TUNEL assay, LC3B immunofluorescence, and immunoblotting. Co-treatment significantly suppressed cell proliferation and induced autophagy and caspase-independent, necrotic cell death. Rapamycin/crizotinib simultaneously inhibited mTORC1 (evidenced by S6 kinase and RPS6 dephosphorylation) and ALK signaling (ALK, AKT, STAT3 dephosphorylation), and crizotinib suppressed the adverse AKT activation induced by rapamycin.In conclusion, co-treatment with rapamycin and crizotinib is effective in suppressing MPM tumor growth and should be further explored as a therapeutic alternative in mesothelioma.

Activated ALK signals through the ERK\u2013ETV5\u2013RET pathway to drive neuroblastoma oncogenesis

Activating mutations of the ALK receptor occur in a subset of neuroblastoma tumors. We previously demonstrated that Alk mutations cooperate with MYCN overexpression to induce neuroblastoma in mice and identified Ret as being strongly upregulated in MYCN/Alkmut tumors. By a genetic approach in vivo, we now document an oncogenic cooperation between activated Ret and MYCN overexpression in neuroblastoma formation. We show that MYCN/RetM919T tumors exhibit histological features and expression profiles close to MYCN/Alkmut tumors. We show that RET transcript levels decrease precedes RET protein levels decrease upon ALK inhibition in neuroblastoma cell lines. Etv5 was identified as a candidate transcription factor regulating Ret expression from murine MYCN/Alkmut tumor transcriptomic data. We demonstrate that ETV5 is regulated both at the protein and mRNA levels upon ALK activation or inhibition in neuroblastoma cell lines and that this regulation precedes RET modulation. We document that ALK activation induces ETV5 protein upregulation through stabilization in a MEK/ERK-dependent manner. We show that RNAi-mediated inhibition of ETV5 decreases RET expression. Reporter assays indicate that ETV5 is able to drive RET gene transcription. ChIP-seq analysis confirmed ETV5 binding on the RET promoter and identified an enhancer upstream of the promoter. Finally, we demonstrate that combining RET and ALK inhibitors reduces tumor growth more efficiently than each single agent in MYCN and AlkF1178L-driven murine neuroblastoma. Altogether, these results define the ERK–ETV5–RET pathway as a critical axis driving neuroblastoma oncogenesis downstream of activated ALK.

Novel method for rapid fluorescence in-situ hybridization of ALK rearrangement using non-contact alternating current electric field mixing

Echinoderm microtubule-associated protein-like 4 gene and anaplastic lymphoma kinase gene (EML4-ALK) rearrangement is a key driver mutation in non-small cell lung cancer (NSCLC). Although Break-Apart ALK fluorescence in situ hybridization (FISH) is a reliable diagnostic method for detecting ALK gene rearrangement, it is too costly and time-consuming for use as a routine screening test. Our aim was to evaluate the clinical utility of a novel rapid FISH (RaFISH) method developed to facilitate hybridization. RaFISH takes advantage of the non-contact mixing effect of an alternating current (AC) electric field. Eighty-five specimens were used from patients diagnosed with NSCLC identified immunohistochemically as ALK 0, (1/2+) or (3+). With RaFISH, the ALK test was completed within 4.5 h, as compared to 20 h needed for the standard FISH. Although RaFISH produced results more promptly, the staining and accuracy of the ALK evaluation with RaFISH was equal to the standard. We found 97.6% agreement between FISH and RaFISH based on the status of the ALK signals. These results suggest RaFISH could be used as a clinical tool to promptly determine ALK status.

The scaffolding protein Cnk binds to the receptor tyrosine kinase Alk to promote visceral founder cell specification in Drosophila.

In Drosophila melanogaster, the receptor tyrosine kinase (RTK) anaplastic lymphoma kinase (Alk) and its ligand jelly belly (Jeb) are required to specify muscle founder cells in the visceral mesoderm. We identified a critical role for the scaffolding protein Cnk (connector enhancer of kinase suppressor of Ras) in this signaling pathway. Embryos that ectopically expressed the minimal Alk interaction region in the carboxyl terminus of Cnk or lacked maternal and zygotic cnk did not generate visceral founder cells or a functional gut musculature, phenotypes that resemble those of jeb and Alk mutants. Deletion of the entire Alk-interacting region in the cnk locus affected the Alk signaling pathway in the visceral mesoderm and not other RTK signaling pathways in other tissues. In addition, the Cnk-interacting protein Aveugle (Ave) was critical for Alk signaling in the developing visceral mesoderm. Alk signaling stimulates the MAPK/ERK pathway, but the scaffolding protein Ksr, which facilitates activation of this pathway, was not required to promote visceral founder cell specification. Thus, Cnk and Ave represent critical molecules downstream of Alk, and their loss genocopies the lack of visceral founder cell specification of Alk and jeb mutants, indicating their essential roles in Alk signaling.

Inflammatory myofibroblastic tumor of the uterus: a clinicopathological, immunohistochemical, and molecular analysis of 13 cases highlighting their broad morphologic spectrum

Inflammatory myofibroblastic tumors of the uterus are rare, and although most have a favorable prognosis, a small subset exhibit extrauterine disease, recur, or cause death. In this study, we evaluated the morphology and immunoprofile of 13 uterine inflammatory myofibroblastic tumors, including four with aggressive behavior. ALK rearrangements were detected by fluorescence in situ hybridization and fusion partners by anchored multiplex assay. Patients ranged from 8 to 63 (mean 39) years and tumors from 2.5 to 20 (mean 7.4) cm. Myxoid, compact, and hyalinized patterns were noted in 13, 12, and 2 tumors, ranging from 1 to 100%, 5 to 99%, and 0 to 5%, respectively. Nuclear atypia was mild in six (46%), moderate in five (38%), and severe in two (15%), with ganglion-like cells in two tumors. Mitoses ranged from 0 to 24 (mean 5) per 10 high-power fields. Inflammation was mild in five (38%), moderate in three (23%), and marked in five (38%), consisting of a lymphoplasmacytic infiltrate that was lymphocyte-predominant in six (46%). Lymphovascular invasion was noted in two (15%) and necrosis in eight (62%). All but one tumor were ALK-positive by immunohistochemistry, with granular cytoplasmic staining in nine (82%). ALK rearrangements (tested in 10) were detected in eight and was absent in one. The remaining tumor showed an isolated green 5′ ALK signal. Fusion partners were identified in 10 (77%) and included THBS1 (n=3), IGFBP5 (n=2), DES (n=2), SEC31 (n=1), TPM3 (n=1), and TIMP3 (n=1). Size ≥8 cm was predictive of aggressive behavior (P<0.01), with increased mitoses (≥7 per 10 high-power fields), lymphovascular invasion, and compact-predominance approaching statistical significance. These data show that inflammatory myofibroblastic tumors of the uterus are morphologically heterogenous with frequent ALK expression and a variety of ALK fusion partners. Recognition of this rare mesenchymal neoplasm is crucial as those with aggressive behavior can potentially be treated with tyrosine kinase inhibitors.