Anaplastic Lymphoma Kinase Kinase Inhibitors Research Articles

Therapeutic benefit of the dual ALK/FAK inhibitor ESK440 in ALK-driven neuroblastoma

Neuroblastoma (NB) is a predominantly pediatric cancer with greater than 90% of cases arising in children under the age of five. More than half of patients have metastases detected at diagnosis, and high-risk disease is associated with five-year survival rates of only 50–60 %. Standard therapy involves highly toxic chemotherapy, surgery, radiation, and immunotherapy, and less toxic, more specific targeted therapies are urgently needed. Genomic studies have identified common driver aberrations in high-risk NB, such as MYCN amplification. In addition, a proportion of high-risk patients harbor amplification or activating mutations in anaplastic lymphoma kinase (ALK), and co-occurrence of ALK mutations and MYCN amplification have been associated with aggressive disease. In this study, we analyzed the efficacy of a Phase Ia-cleared, orally bioavailable dual ALK and focal adhesion kinase (FAK) inhibitor, ESK440, in multiple preclinical NB models. ESK440 potently inhibited proliferation of NB cell lines, with increased sensitivity in cell lines harboring ALK aberrations. ALK, FAK, and downstream target activation were rapidly decreased upon ESK440 treatment, and this was associated with impaired cellular migration and invasion. Importantly, ESK440 treatment also decreased MYCN levels. NB cell line and patient-derived xenograft studies showed significant reduction in tumor growth in ESK440-treated mice with no signs of toxicity. In certain NB models, ESK440 showed comparable or enhanced efficacy to lorlatinib, another clinical ALK inhibitor, and a lorlatinib-resistant cell line (COG-N-561 LR) retained sensitivity to ESK440. These preclinical results indicate that ESK440 is a promising targeted agent for ALK-driven NB and support future clinical studies to evaluate its efficacy in NB patients.

ALK Inhibitor Plus Vinblasitine for Refractory/Relapsed Pediatric ALK+ Anaplastic Large Cell Lymphoma: A Prospective, One-Arm, Open-Label Real-World Study

Background: Refractory and relapsed (r/r) anaplastic lymphoma kinase (ALK)-positive anaplastic large cell Lymphoma(ALK+ALCL) have a poor prognosis. Studies had confirmed vinblastine (VBL) may be an effective treatment for relapsed ALCL and ALK inhibitors may have high efficacy and tolerability in patients carrying ALK fusions. Therefore, we put forward a hypothesis that for those r/r ALK+ALCL patients with poor chemotherapy tolerance and effect, combining ALK inhibitors with vinblastine may have a sustained anti-tumor effect and good tolerance.Aims: To assess the efficacy and safety of ALK inhibitors combined with VBL in pediatric relapsed/refractory (r/r) ALK+ ALCL.Methods: Patients aged between 0 and 18 years with r/r ALK+ ALCL were included in this trial. ALK inhibitors are given orally with a converted dosage according to body surface areaand VBL was given with injection once a week at 4-6 mg/(m2.week). And no intensive chemotherapy and hematopoietic stem cell transplantation will be in our study.We may decrease the dosage of VBL or delete VBL if patients suffer severe bone marrow suppression, repeated infections, and peripheral neuritis and other VBL-related toxicities. Available ALK inhibitors included crizotinib(CZ), alectinib(AL) and ceritinib(CER). Patients without CNS involvement took CZ, and patients with CNS involvement took AL or CER. A cycle of therapy is 28 days. Evaluation for responses toxicities were monitored and recorded.Results:27 patients were enrolled in this trial between April 2018 and April 2021. The median age was 8.3 years old(ranging from 0.75 to 16), male/female ratio is19:8. By St.jude's staging, 20 cases were in stage III (74.1%), 7 cases in stage IV (25.9%) including 3 cases (11.1%) with CNS involvement at initial diagnosis. Before being enrolled in our study, 6 patient (22.2%) failed to achieve CR with prior 4-10 chemotherapy regimens, 21 patients (77.8%) relapsed after an average of 5-16 courses of standard pulse chemotherapy regimens. After 1st cycle of treatments, 62.9%(17/26) achieved comlpele remission(CR) without measurable tumors and ALK gene transcription, no progressed cases. Additional 6 case got CR after 2-10 month(23.1%). In general, 7 patients withdraw due to death, progress, ineffectiveness, economics, adverse reactions. The treatment retention rate was ,7.1%（20/7），objective response rate (ORR) was 85.2%(23/27), best complete remission rate(CRR) was 85.2%(23/27), disease control rate(DCR) was 92.5%(25/27), average duration of CR was 14.85 months(0-36months).Toxicities included nausea and vomiting, stomachache, diarrhea(81.5%,22/27, one or more above toxicities), neutropenia (27/27), pneumonia(7.4%, 2/27), sepsis(7.4%, 2/27), creatine kinase-MB elevation (81.5%,22/27,all are in crizotinib group including 2 abnormal ECG cases), liver enzyme elevation (63.%,17//27), intestinal obstruction(7.4%, 2/26). 2 cases relapsed because of the treatment discontinuation due to severe elevated liver enzymes.Summary/Conclusion: ALK inhibitors combined with VBL may rapidly induce the tumor remission of r/r ALK+ALCL and the tolerance is good. Combination therapy may induce a more lasting remission in for patients without BM involvement. Patients with BM involvement are more likely to fail treatment. Sequential use of ALK kinase inhibitors may be an efficient strategy to counter drug resistance.More data and longer follow-up time are needed to support our study. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Two novel strategies to overcome the resistance to ALK tyrosine kinase inhibitor drugs: Macrocyclic inhibitors and proteolysis-targeting chimeras.

Lung cancer is the most malignant tumor in the worldwide. About 3%‐5% non‐small cell lung cancer (NSCLC) patients carry anaplastic lymphoma kinase (ALK) gene fusions and receive great benefits from ALK‐targeted therapy. However, drug resistance inevitably occurs even with the most potent inhibitor drug lorlatinib. About half of the resistance are caused by alteration in ALK proteins for earlier ALK TKI drugs and near one‐third of loratinib resistant cases are caused by compound mutations without current effective treatment strategy in clinic. Novel strategies are in great need to overcome drug resistance. Lately, two novel strategies have been developed and attracted great attentions for their potentials to overcome drug resistance problems: (1) developed small compact macrocyclic ALK kinase inhibitors and (2) developed ALK targeted proteolysis‐targeting chimera (PROTAC) drugs. The macrocyclic molecules are small and compact in size, brain barrier permeable, and highly potent against lorlatinib‐resistant compound mutations. Developed ALK targeted PROTAC molecules could degrade oncogenic ALK driver proteins. Some showed superiority in killing ALK positive cancer cells and inhibiting the growth of cells expressing G1202R resistant ALK proteins comparing to inhibitor drugs. The update on these two treatment strategies was reviewed.

Arsenic trioxide inhibits anaplastic lymphoma kinase (ALK)‐positive diffuse large B‐cell lymphoma through targeting ALK‐fusion oncoprotein

Arsenic trioxide inhibits anaplastic lymphoma kinase (ALK)‐positive diffuse large B‐cell lymphoma through targeting ALK‐fusion oncoprotein

Anaplastic lymphoma kinase fusions: Roles in cancer and therapeutic perspectives.

Receptor tyrosine kinase (RTK) anaplastic lymphoma kinase (ALK) serves a crucial role in brain development. ALK is located on the short arm of chromosome 2 (2p23) and exchange of chromosomal segments with other genes, including nucleophosmin (NPM), echinoderm microtubule-associated protein-like 4 (EML4) and Trk-fused gene (TFG), readily occurs. Such chromosomal translocation results in the formation of chimeric X-ALK fusion oncoproteins, which possess potential oncogenic functions due to constitutive activation of ALK kinase. These proteins contribute to the pathogenesis of various hematological malignancies and solid tumors, including lymphoma, lung cancer, inflammatory myofibroblastic tumors (IMTs), Spitz tumors, renal carcinoma, thyroid cancer, digestive tract cancer, breast cancer, leukemia and ovarian carcinoma. Targeting of ALK fusion oncoproteins exclusively, or in combination with ALK kinase inhibitors including crizotinib, is the most common therapeutic strategy. As is often the case for small-molecule tyrosine kinase inhibitors (TKIs), drug resistance eventually develops via an adaptive secondary mutation in the ALK fusion oncogene, or through engagement of alternative signaling mechanisms. The updated mechanisms of a variety of ALK fusions in tumorigenesis, proliferation and metastasis, in addition to targeted therapies are discussed below.

P1.13-05 Integrin β3 Inhibition Enhances the Antitumor Activity of Alk Inhibitor in Alkrearranged NSCLC

Anaplastic lymphoma kinase (ALK)-positive cancers are sensitive to small molecule ALK kinase inhibitors, but most cases experience failure following treatment. Hence, additional drug targets and combination therapeutic treatments are needed. We investigated gene expression that is regulated by the expression of ALK and explored its roles in cancer progression and therapeutic implication. We screened ALK-rearranged non-small cell lung cancer (NSCLC) cases using immunohistochemistry and fluorescence in situ hybridization, and then conducted multiplex gene expression analysis. We also performed a clinicopathological analysis to validate the findings. Additional cellular experiments, including inhibition and migration assays, and in vivo lung cancer model studies were performed. Among patients with ALK-rearranged NSCLC, integrin β3 (ITGB3) was one of the overexpressed genes in comparison with that in ALK-negative NSCLC (P = 0.0003). ALK and integrin β3 expression were positively correlated, and we discovered that high integrin β3 mRNA expression was associated with metastasis and more advanced tumor stages (P < 0.005; P < 0.05). Furthermore, we found that inhibition of both ALK and integrin β3 led to increased drug sensitivity in vitro and in vivo (both P < 0.05). We discovered a positive correlation between ALK and integrin β3 expression levels in ALK rearranged NSCLC. Our findings suggest that high integrin β3 expression in ALK-rearranged NSCLC is associated with tumor progression and a worse prognosis. This demonstrates the prognostic value of integrin β3 and provides a rationale for combination treatment with ALK and integrin β3 inhibitors in patients with ALK-rearranged NSCLC.

Integrin β3 Inhibition Enhances the Antitumor Activity of ALK Inhibitor in ALK-Rearranged NSCLC.

Purpose: Anaplastic lymphoma kinase (ALK)-positive cancers are sensitive to small-molecule ALK kinase inhibitors, but most cases experience failure following treatment. Hence, additional drug targets and combination therapeutic treatments are needed. We investigated gene expression that is regulated by the expression of ALK and explored its roles in cancer progression and therapeutic implication.Experimental Design: We screened ALK-rearranged non-small cell lung cancer (NSCLC) cases using immunohistochemistry and fluorescence in situ hybridization and then conducted multiplex gene expression analysis. We also performed a clinicopathologic analysis to validate the findings. Additional cellular experiments, including inhibition and migration assays, and in vivo lung cancer model studies were performed.Results: Among patients with ALK-rearranged NSCLC, integrin β3 (ITGB3) was one of the overexpressed genes in comparison with that in ALK-negative NSCLC (P = 0.0003). ALK and integrin β3 expression were positively correlated, and we discovered that high integrin β3 mRNA expression was associated with metastasis and more advanced tumor stages (P < 0.005; P < 0.05). Furthermore, we found that inhibition of both ALK and integrin β3 led to increased drug sensitivity in vitro and in vivo (both P < 0.05).Conclusions: We discovered a positive correlation between ALK and integrin β3 expression levels in ALK-rearranged NSCLC. Our findings suggest that high integrin β3 expression in ALK-rearranged NSCLC is associated with tumor progression and a worse prognosis. This finding demonstrates the prognostic value of integrin β3 and provides a rationale for combination treatment with ALK and integrin β3 inhibitors in patients with ALK-rearranged NSCLC. Clin Cancer Res; 24(17); 4162-74. ©2018 AACR.

Targeting ALK in pediatric RMS does not induce antitumor activity in vivo.

The anaplastic lymphoma kinase (ALK) has been demonstrated to be a valid clinical target in diseases such as anaplastic large cell lymphoma and non-small cell lung cancer. Recent studies have indicated that ALK is overexpressed in pediatric rhabdomyosarcoma (RMS) and hence we hypothesized that this kinase may be a suitable candidate for therapeutic intervention in this tumor. We evaluated the expression of ALK in a panel of pediatric RMS cell lines and patient-derived xenografts (PDX), and sensitivity to ALK inhibitors was assessed both in vitro and in vivo. Essentially, all RMS lines were sensitive to crizotinib, NVP-TAE684 or LDK-378 in vitro, and molecular analyses demonstrated inhibition of RMS cell proliferation following siRNA-mediated reduction of ALK expression. However, in vivo PDX studies using ALK kinase inhibitors demonstrated no antitumor activity when used as single agents or when combined with standard of care therapy (vincristine, actinomycin D and cyclophosphamide). More alarmingly, however, crizotinib actually accelerated the growth of these tumors in vivo. While ALK appears to be a relevant target in RMS in vitro, targeting this kinase in vivo yields no therapeutic efficacy, warranting extreme caution when considering the use of these agents in pediatric RMS patients.

Non-Canonical Thinking for Targeting ALK-Fusion Onco-Proteins in Lung Cancer.

Anaplastic lymphoma kinase (ALK) gene rearrangements have been identified in lung cancer at 3–7% frequency, thus representing an important subset of genetic lesions that drive oncogenesis in this disease. Despite the availability of multiple FDA-approved small molecule inhibitors targeting ALK fusion proteins, drug resistance to ALK kinase inhibitors is a common problem in clinic. Thus, there is an unmet need to deepen the current understanding of genomic characteristics of ALK rearrangements and to develop novel therapeutic strategies that can overcome ALK inhibitor resistance. In this review, we present the genomic landscape of ALK fusions in the context of co-occurring mutations with other cancer-related genes, pointing to the central role of genetic epistasis (gene-gene interactions) in ALK-driven advanced-stage lung cancer. We discuss the possibility of targeting druggable domains within ALK fusion partners in addition to available strategies inhibiting the ALK kinase domain directly. Finally, we examine the potential of targeting ALK fusion-specific neoantigens in combination with other treatments, a strategy that could open a new avenue for the improved treatment of ALK positive lung cancer patients.

Resistance to Crizotinib in Advanced Non-Small Cell Lung Cancer (NSCLC) with ALK Rearrangement: Mechanisms, Treatment Strategies and New Targeted Therapies.

Non-small cell lung cancers (NSCLCs) harboring anaplastic lymphoma kinase (ALK) rearrangement are generally responsive to treatment with ALK tyrosine kinase inhibitors (TKIs). Crizotinib is the first-in-class TKI approved as front-line or salvage therapy in advanced ALK-rearranged NSCLC. Unfortunately, drug resistance develops after initial benefit, through a variety of mechanisms preserving or not the dominance of ALK signaling in the crizotinib-resistant state. The distinction between patients who preserve ALK dominance (secondary mutations alone or in combination with the number of copy ALK gain) compared to those that have decreased ALK dominance (separate or second oncogenic drivers, with or without concurrent persistence of the original ALK signal) is important in order to overcome resistance. Novel second-generation ALK inhibitors are currently in clinical development with promising results in ALK-rearranged NSCLC, as well as in crizotinib-resistant patients. Among these, ceritinib in the United States was granted by Food and Drug Administration accelerated approval for treatment of patients with ALK-rearranged, metastatic NSCLC with progression disease on or intolerance to crizotinib. Fully understanding of the different mechanisms of resistance to crizotinib will help us to continue to exploit personalized medicine approaches overcoming crizotinib resistance in these patients in the future. This review aims to discuss on strategy overcoming crizotinib-resistance starting from molecular mechanisms of resistance until novel ALK kinase inhibitors in ALK-rearranged NSCLC patients.

Primary and Metastatic Cutaneous Melanomas Express ALK Through Alternative Transcriptional Initiation.

A number of common driver mutations have been identified in melanoma, but other genetic or epigenetic aberrations are also likely to play a role in the pathogenesis of melanoma and present potential therapeutic targets. Translocations of the anaplastic lymphoma kinase (ALK), for example, have been reported in spitzoid melanocytic neoplasms leading to kinase-fusion proteins that result in immunohistochemically detectable ALK expression. In this study, we sought to determine whether ALK was also expressed in nonspitzoid primary and metastatic cutaneous melanomas. ALK immunohistochemistry was performed on 603 melanomas (303 primary and 300 metastatic tumors) from 600 patients. ALK immunohistochemistry expression was identified in 7 primary and 9 metastatic tumors. In 5 of 7 primary tumors and in 6 of 9 metastatic lesions, the majority of tumor cells were immunoreactive for ALK. In the other 2 primary and 3 metastatic lesions, positive staining was identified in less than half of the tumor cells. ALK positivity was found in the presence or absence of BRAF or NRAS mutations. In contrast to prior observations with ALK-positive Spitz tumors, none of the ALK-positive melanomas harbored a translocation. Instead, the ALK-positive melanomas predominantly expressed the recently described ALK isoform, ALK, which lacks the extracellular and transmembrane domains of wild-type ALK, consists primarily of the intracellular tyrosine kinase domain, and originates from an alternative transcriptional initiation site within the ALK gene. The findings are clinically relevant as patients with metastatic melanoma who have ALK expression may potentially benefit from treatment with ALK kinase inhibitors.

Abstract C82: Induction of resistances to crizotinib in lung patient derived xenograft

Abstract Background. Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase, and its mutation, over-expression and gene fusion have been associated with various cancers. EML4-ALK fusion has been confirmed to be an oncogenic driver for a small subset of the lung cancers (∼4% of NSCLC)1, and becomes an excellent drug target that led to the development of the first effective therapy, crizotinib, a tyrosine kinase inhibitor for anaplastic lymphoma kinase, for this disease 2,3. However, like any other cancer therapy so far, the treatment always led to the development of resistance, rendering them ineffective in the end4. Understanding the mechanisms causing these resistances can potentially facilitate overcoming the resistance and extend patients' life5,6. However, lack of experimental model hinders this understanding. Method. We have recently established a large collection of patient derived xenografts (∼350 PDXs)7, and we screened some of them for alk gene fusions. We then tested the positive model for sensitivity to crizothinib, and keep it under several rounds of crizotinib treatments to select resistant model. The induced resistant model was subjected to genomic analysis to identify the changes that might potentially be responsible for the resistance. Results. We identified one model, NSCLC LU1656, containing EML4-ALK fusion with elevated ALK expression. It has also been shown to respond well to crizotinib in vivo. The continued treatment eventually led to the development of resistance to crizotinib (LU2445), a situation that might occur in patients in the clinic under the same treatment. We have performed transcriptome sequencing of the parental sensitive tumor (LU1656) and the selected resistant tumor (LU2445). So far, we found both models expressed similar high levels of expression of ALK, but no additional mutations in ALK gene. There are other alterations either genetically or epigenetically, some seemingly related to the ALK signaling pathways. However, their role in resistance still need to be confirmed. Conclusions. Induced crizotinib resistance in ALK-fusion lung PDX can be useful to investigate crizotinib resistant mechanism and future drugs overcoming the resistance.

Clinical Implications of Variant ALK FISH Rearrangement Patterns

Break-apart fluorescence in situ hybridization (FISH) is the FDA-approved assay for detecting anaplastic lymphoma kinase (ALK) rearrangements in non-small-cell lung cancer (NSCLC), identifying patients who can gain dramatic benefit from ALK kinase inhibitors. Assay interpretation can be technically challenging, and either splitting of the 5' and 3' probes or loss of the 5' probe constitute rearrangement. We hypothesized that there may be clinical differences depending on rearrangement pattern on FISH. An IRB-approved database of NSCLC patients at Dana-Farber Cancer Institute was queried for ALK rearrangement. Clinical characteristics and response to crizotinib were reviewed. Immunohistochemistry (IHC) and targeted next-generation sequencing (NGS) were obtained when available. Of 1614 NSCLC patients with ALK testing, 82 patients (5.1%) had ALK rearrangement by FISH: 30 patients with split signals, 25 patients with 5' deletion, and 27 patients with details unavailable. Patients with 5' deletion were older (p = 0.01) and tended to have more extensive smoking histories (p = 0.08). IHC was positive for ALK rearrangement in all 27 patients with FISH split signals, whereas three of 21 patients with FISH 5' deletion had negative IHC (p = 0.05). Targeted NGS on two of three cases with discordant FISH and IHC results did not identify ALK rearrangement, instead finding driver mutations in EGFR and KRAS. Patients with 5' deletion treated with crizotinib had a smaller magnitude of tumor response (p = 0.03). Patients with 5' deletion on ALK FISH harbor features less typical of ALK-rearranged tumors, potentially indicating that some cases with this variant are false positives. Corroborative testing with IHC or NGS may be beneficial.

The treatment of advanced non-small-cell lung cancer with anaplastic lymphoma kinase genetic alterations: reality and hopes

Targeted therapies based on molecular diagnostics have opened a new era of personalized medicine in lung cancer treatment. Recently, anaplastic lymphoma kinase (ALK) fusion gene emerged as an important biomarker for identifying a small proportion of non-small-cell lung cancer (NSCLC) patients that will benefit from ALK kinase inhibitor crizotinib, like EGFR activating mutations and EGFR tyrosine kinase inhibitors. Despite the remarkable initial responses, acquired resistance to crizotinib develops within a year and promising second generation of ALK inhibitors are in current development to overcome it. This review will focus on the basic molecular pathology of ALK gene rearrangement in NSCLC, current testing methods, treatment strategies against ALK-positive and crizotinib-resistant NSCLCs.

Current and future treatment of anaplastic lymphoma kinase-rearranged cancer.

Aberrant forms of the anaplastic lymphoma kinase (ALK) are involved in the pathogenesis of several types of cancer, including anaplastic large cell lymphoma, non-small-cell lung cancer (NSCLC), inflammatory myofibroblastic tumors, colorectal cancer, neuroblastoma and others. In general, the ALK catalytic domain is rearranged and fused to a dimerization domain encoded by an unrelated gene. Less frequently, full-length ALK is activated by point mutations. The common theme is unregulated firing of ALK downstream signalling, leading to uncontrolled cell division and increased cell survival. ALK-driven tumors can be treated with Crizotinib, an orally available dual ALK/MET inhibitor, currently approved for advanced ALK-positive NSCLCs. Crizotinib-treated patients achieve high response rates, with an excellent toxicity profile. However, drug-resistant disease often develops, particularly in NSCLC patients. The processes leading to drug resistance include both ALK-dependent (point mutations or gene amplification), as well as ALK-independent mechanisms, which are here briefly discussed. Recently, Ceritinib has been approved for Crizotinib-refractory NSCLC, further extending patients' survival, but resistance again emerged. Novel ALK kinase inhibitors are currently under clinical development, showing great promise for improved efficacy in drug-resistance disease. It is opinion of the author that drug-resistance is likely to arise under any treatment, due to intrinsic heterogeneity and adaptability of cancer. To prevent or delay this phenomenon, we need to treat less advanced disease, with drugs that are rapidly effective in order not to allow enough time for tumor evolution, and we want to have more and more drugs with non-overlapping resistance profiles, for subsequent lines of targeted therapy. Finally, the use of drug combinations may exponentially decrease the chances of resistance.

Patient-derived models of acquired resistance can identify effective drug combinations for cancer.

Targeted cancer therapies have produced substantial clinical responses, but most tumors develop resistance to these drugs. Here, we describe a pharmacogenomic platform that facilitates rapid discovery of drug combinations that can overcome resistance. We established cell culture models derived from biopsy samples of lung cancer patients whose disease had progressed while on treatment with epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors and then subjected these cells to genetic analyses and a pharmacological screen. Multiple effective drug combinations were identified. For example, the combination of ALK and MAPK kinase (MEK) inhibitors was active in an ALK-positive resistant tumor that had developed a MAP2K1 activating mutation, and the combination of EGFR and fibroblast growth factor receptor (FGFR) inhibitors was active in an EGFR mutant resistant cancer with a mutation in FGFR3. Combined ALK and SRC (pp60c-src) inhibition was effective in several ALK-driven patient-derived models, a result not predicted by genetic analysis alone. With further refinements, this strategy could help direct therapeutic choices for individual patients.

Abstract 3716: Overexpression of the adaptor protein CRKL as a mechanism of acquired resistance to Crizotinib in ALK-positive NSCLC

Abstract Background: The fusion of the anaplastic lymphoma kinase (ALK) and echinoderm microtubule-associated protein-like 4 (EML4) is a known oncogenic driver in a subset of non-small cell lung cancer (NSCLC). An ALK/ROS1/MET kinase inhibitor, Crizotinib, was approved in 2011 for the treatment of patients with metastatic ALK+ NSCLC. Despite the dramatic clinical effects of Crizotinib in EML4-ALK positive NSCLC, vast majority of patients subsequently acquire resistance and new therapeutic strategies are needed. Methods and Results: We performed a kinase (n=597) open reading frame screen to identify kinases and phosphoproteins capable of circumventing ALK inhibition in H3122 cell line sensitive to the ALK kinase inhibitor TAE684. The top hit of the screen imparting resistance to TAE684 was the adaptor phospho-protein CRK-like (CRKL), a known substrate of BCR-ABL. To validate our screen, we constructed a tagged form of CRKL and stably expressed it in H3122. H3122CRKL acquired a migratory phenotype, however, its growth rate was comparable to that of the parental cell line. The viability of H3122CRKL was assessed in response to drug dose escalation, confirming that overexpression of CRKL decreased sensitivity of H3122 to Crizotinib 47-fold compared to the control. Analysis of downstream signaling in response to Crizotinib treatment further revealed sustained activation of PI3K/AKT and MAPK/ERK1/2 pathways in CRKL overexpressing cells. Closer examination of signaling in H3122CRKL revealed additional signaling alterations. Most significantly, we found that overexpressing CRKL in H3122 resulted in activation of EGFR. We and others have previously demonstrated that EGFR signaling can mediate Crizotinib resistance. We further examined primary tumor cell lines (n=6), generated from ALK rearranged NSCLC patients who developed resistance to Crizotinib, and 4 demonstrated increased levels of both CRKL and phosphorylated EGFR. To determine if EGFR inhibition could be a therapeutic approach to overcome Crizotinib resistance in CRKL overexpressing cells, cell viability was assessed in response to dual treatment with Crizotinib and Gefitinib. The drug combination displayed robust synergistic effects on growth inhibition of ALK+ CRKL overexpressing cell lines but not of CRKLlow Crizotinib sensitive H3122, highlighting their co-dependence on EGFR. Finally, activation of FAK and SRC family kinases correlated with EGFR activation and CRKL overexpression in H3122CRKL, an observation further corroborated by a 9-fold increase in migratory capacity of H3122CRKL vs. control. Conclusion: Our findings indicate that CRKL overexpression can lead to acquired resistance to ALK inhibition in ALK rearranged NSCLC. CRKL overexpression results in EGFR activation suggesting that therapy directed at both EGFR and EML4-ALK may be effective in treating and/or preventing acquired resistance to Crizotinib. Citation Format: Magda Bahcall, Takaaki Sasaki, Atsuko Ogino, Marzia Capelletti, Mohit Butaney, Pasi A. Jänne. Overexpression of the adaptor protein CRKL as a mechanism of acquired resistance to Crizotinib in ALK-positive NSCLC. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3716. doi:10.1158/1538-7445.AM2014-3716

Flotillin-1 Regulates Oncogenic Signaling in Neuroblastoma Cells by Regulating ALK Membrane Association

Neuroblastomas harbor mutations in the nonreceptor anaplastic lymphoma kinase (ALK) in 8% to 9% of cases where they serve as oncogenic drivers. Strategies to reduce ALK activity offer clinical interest based on initial findings with ALK kinase inhibitors. In this study, we characterized phosphotyrosine-containing proteins associated with ALK to gain mechanistic insights in this setting. Flotillin-1 (FLOT1), a plasma membrane protein involved in endocytosis, was identified as a binding partner of ALK. RNAi-mediated attenuation of FLOT1 expression in neuroblastoma cells caused ALK dissociation from endosomes along with membrane accumulation of ALK, thereby triggering activation of ALK and downstream effector signals. These features enhanced the malignant properties of neuroblastoma cells in vitro and in vivo. Conversely, oncogenic ALK mutants showed less binding affinity to FLOT1 than wild-type ALK. Clinically, lower expression levels of FLOT1 were documented in highly malignant subgroups of human neuroblastoma specimens. Taken together, our findings suggest that attenuation of FLOT1-ALK binding drives malignant phenotypes of neuroblastoma by activating ALK signaling.

Potential Therapies for Anaplastic Lymphoma Kinase-Driven Tumors in Children: Progress to Date

Anaplastic lymphoma kinase (ALK) is an oncogenic tyrosine kinase that is deregulated due to a variety of molecular mechanisms in pediatric cancer. They include chromosomal translocations, activation mutations, and gene amplifications. Since the initial discovery of ALK as an oncogenic tyrosine kinase involved in the chromosomal translocation t(2, 5)(p23;q35) in 1994, more than 20 translocation partners of ALK have been identified in various cancers. Furthermore, deregulation of ALK tyrosine kinase activity is critical for the pathogenesis of several other pediatric tumors, including neuroblastomas and inflammatory myofibroblastic tumors. The recent discovery of ALK translocations in adult lung cancer patients (non-small cell lung cancer) has accelerated the development of inhibitors of ALK tyrosine kinase as therapeutic agents. While excellent clinical response has been observed in many patients, the acquisition of clinical resistance to ALK inhibition highlights the need for development of second-generation ALK kinase inhibitors and/or combination therapies that target downstream signaling mediators or antibody drug conjugates. This article provides an update on the spectrum of ALK-driven tumors in the pediatric population and the potential therapies which target these tumors.

ALK and ROS1 as a joint target for the treatment of lung cancer: a review.

Rearrangements of the anaplastic lymphoma kinase (ALK) have been described in multiple malignancies, including non-small cell lung cancer (NSCLC). ALK fusions have gain of function properties while activating mutations in wild-type ALK can also occur within the tyrosine kinase domain. ALK rearrangements define a new molecular subtype of NSCLC that is exquisitely sensitive to ALK inhibition. Crizotinib, an orally available small molecule ATP-mimetic compound which was originally designed as a MET inhibitor, was recognized to have "off-target" anti-ALK activity and has been approved in the USA for the treatment of patients with ALK-positive NSCLC. Chromosomal rearrangements involving the ROS1 receptor tyrosine kinase have also been recently described in NSCLC, while crizotinib is currently under clinical trial in this molecular subset of NSCLC patients. The basic approaches of any computer aided drug design work in terms of structure and ligand based drug design. Details of each of these approaches should be covered with an emphasis on utilizing both in order to develop multi-targeted small-molecule kinase inhibitors. Such multi-targeted tyrosine kinase inhibitors can have antiproliferative activity against both ROS1and ALK rearranged NSCLC. Herein, we highlight the importance of targeting these proteins and the advances in optimizing more potent and selective ALK and ROS1 kinase inhibitors.