EML4-ALK Fusion Gene Research Articles

ISY-7-1 - Alectinib vs Crizotinib

The EML4-ALK fusion gene is one of the key oncogenic drivers and identified in 4%-6% of patients with NSCLC. NSCLC harboring ALK rearrangements (ALK+ NSCLC) is highly sensitive to therapy with an ALK-targeted inhibitor. Crizotinib is a first-in-class ALK tyrosine kinase inhibitor. Crizotinib showed a favorable response rate (approx. 60%) in phase I and Phase II trials. Moreover, phase III trials have shown the superior efficacy of crizotinib in response rate (RR) and progression-free survival (PFS) when compared with standard 1st-line platinum/pemetrexed chemotherapy or 2nd-line monotherapy (docetaxel or pemetrexed) in ALK+ NSCLC. The Japan Lung Cancer Society Guidelines recommend crizotinib as Grade A for 1st-line or 2nd-line therapy on ALK+ NSCLC. However the majority of patients experienced crizotinib resistance within 1 year. Alectinib is a highly selective, CNS-active, inhibitor of ALK tyrosine kinase developed in Japan. Phase I/II study has shown a promising effect (RR; 93.5%, PFS; 27.7M) of Alectinib in 46 ALK inhibitor naïve patients with ALK+ NSCLC. Several clinical trials have shown that alectinib displays clinical activity in ALK+ NSCLC patients who have progressed on crizotinib. Chugai Pharmaceutical Co., Ltd. announced in a press release that randomized a phase III study evaluating alectinib versus crizotinib in treatment naïve ALK+ NSCLC was stopped early because the study met its endpoint, demonstrating superior PFS in patients receiving alectinib. My presentation will focus on the selective use or sequence of alectinib and crizotinib via findings to date and conceivable future prospects for therapeutic strategy on ALK+ NSCLC in Japan.

Crizotinib for ALK rearrangement-positive non-small cell lung cancer patients with central nervous system metastasis

Patients with central nervous system (CNS) metastases in general experience have a deterioration in performance status and a limited survival time (1). CNS metastasis of non-small cell lung cancer (NSCLC) has been the subject of renewed interest of late given that small-molecule tyrosine kinase inhibitors (TKIs), such as those that target activated forms of the epidermal growth factor receptor (EGFR), have the potential to improve local tumor control in molecularly selected individuals. Given that the concentration of EGFR-TKIs is much lower in cerebrospinal fluid (CSF) than in plasma, however, frequent isolated CNS metastasis, without other systemic progression, has been detected in patients with advanced NSCLC who show a response to these drugs (2). Similar concerns have also been raised for patients with NSCLC positive for the EML4-ALK fusion gene treated with the anaplastic lymphoma kinase (ALK)-targeted TKI crizotinib.

Methylation Status of the SOCS3 Gene Promoter in H2228 Cells and EML4-ALK-positive Lung Cancer Tissues

背景与目的人类棘皮动物微管相关蛋白样4（echinoderm microtubule-associated-protein-like 4, EML4）和人类间变性淋巴瘤激酶（anaplastic lymphoma kinase, ALK）融合基因EML4-ALK是新发现的非小细胞肺癌的驱动基因，患者具有独特的临床病理生理特征，ALK基因下游信号通路的异常持续激活是其重要的下游信号通路，而导致其下游基因持续激活的原因不明。细胞因子信号转导抑制因子（suppressor of cytokine signaling, SOCS）是一类在细胞信号转导过程中起重要作用的负调控因子，主要通过抑制JAK蛋白酪氨酸激酶（janus protein tyrosine kinase, JAK）信号传导和转录激活因子（signal transducer and activator of transcription, STAT）即JAK-STAT等信号通路来调控细胞的增殖、分化和凋亡。肿瘤中常存在SOCS基因的甲基化异常导致的失活，从而导致JAK2-STAT等信号通路持续异常活化。本研究的目的在于探讨EML4-ALK阳性H2228细胞和肺癌组织中SOCS3启动子区甲基化状态。方法甲基化特异性PCR检测EML4-ALK阳性H2228肺癌细胞及肺癌组织中SOCS3启动子区的甲基化状态，并通过测序验证。DNA甲基转移酶抑制剂5’-Aza-dC处理H2228细胞，并通过Real-time PCR和Western blot检测SOCS3的表达水平变化。结果MSP及测序分析发现EML4-ALK阳性细胞株H2228中存在SOCS3启动子区甲基化；7例EML4-ALK阳性肺癌组织中的3例存在SOCS3启动子区甲基化，H2228细胞经过5’-Aza-dC去甲基化处理后SOCS3的表达明显增加。结论EML4-ALK（+）的H2228肺癌细胞及部分肺癌组织中存在SOCS3启动子区的异常甲基化，可能是EML4-ALK阳性肺癌的重要发病机制。

Abstract 2103: Activating alternative receptor tyrosine kinases induced alectinib-resistance in ALK rearranged non-small cell lung cancer cells

Abstract Background The second-generation anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor (TKI), alectinib, demonstrated high response rate, long response duration and a favorable toxic profile in patients with ALK-rearranged advanced non-small cell lung cancer in a phase II study (Lancet Oncol 14:590-8, 2013). However, even this promising drug is predicted to develop acquired resistance. Therefore, we investigated the mechanisms of resistance using two alectinib-resistant cell lines. Methods We established alectinib-resistant cell lines, H2228/CHR and ABC-11/CHR, from H2228 (EML4-ALK fusion genes variant 3a/b E6) and ABC-11 (EML4-ALK fusion genes variant 3b E6) respectively, by continuous exposure to alectinib. They were characterized using MTT assay, Western blotting, receptor tyrosine kinase array, ELISA, FISH, RT-PCR, and xenograft models. Results H2228/CHR and ABC-11/CHR cells were 117- and 40-fold more resistant than the parental lines, respectively, and maintained downstream AKT and ERK phosphorylation even in the presence of 10 μM alectinib. There were no ALK secondary mutations in those resistant cell lines. H2228/CHR lost the EML4-ALK fusion gene, and exhibited increased activation of insulin-like growth factor-1 receptor (IGF-1R) and human epidermal growth factor receptor 3 (HER3) with overexpression of the HER3 ligand neuregulin 1. Accordingly, pharmacologic inhibition of IGF-1R and HER3 signaling overcame the resistance. In ABC-11/CHR, MET was activated by stimulated hepatocyte growth factor (HGF) autocrine signaling. We found HGF gene translocation underlying the HGF autocrine system. Anti-HGF antibody suppressed the MET activation and combined treatment with alectinib and anti-HGF antibody or a MET inhibitor suppressed downstream signaling in ABC-11/CHR cells. Finally, crizotinib, which targets both ALK and MET, most effectively inhibited the growth of ABC-11/CHR both in vitro and in vivo. Conclusions We identified novel alectinib resistance mechanisms caused by the activation of alternative tyrosine kinase receptors. Our findings provide new insights into constructing a therapeutic strategy for ALK-positive lung cancer. Citation Format: Hideko Isozaki, Eiki Ichihara, Masayuki Yasugi, Nagio Takigawa, Kadoaki Ohashi, Toshio Kubo, Takashi Ninomiya, Nobuaki Ochi, Daisuke Minami, Kenichiro Kudo, Yuka Kato, Hiroe Kayatani, Tomoki Tamura, Kiichiro Ninomiya, Toshio Higo, Tsuyoshi Makimoto, Akiko Sato, Katsuyuki Hotta, Kunio Matsumoto, Toshiaki Sendo, Mitsune Tanimoto, Katsuyuki Kiura. Activating alternative receptor tyrosine kinases induced alectinib-resistance in ALK rearranged non-small cell lung cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2103.

Abstract LB-109: Identification of anaplastic lymphoma kinase fusions in clear cell renal cell carcinoma

Abstract As the most common type of renal cancer, clear cell renal cell carcinoma (ccRCC) with advanced stages constitutes a continued major challenge for uro-oncologists where identification of novel driver mutations and development of novel targeted therapies against them remain an unmet need. Aberrations of the anaplastic lymphoma kinase (ALK) gene have been implicated in the pathogenesis of multiple human cancers where ALK represents a rational therapeutic target as demonstrated in lung cancer with ALK rearrangement. In this study, we performed the screening of ALK expression in 87 pathologically defined ccRCC by immunohistochemistry (IHC) using a newly developed rabbit anti-human ALK monoclonal antibody (clones D5F3). Four patients were positive for ALK expression as determined by IHC among which 2 cases were further confirmed by fluorescence in situ hybridization (FISH) assay using the Vysis LSI ALK dual color break-apart probe; furthermore, we detected the presence of EML4-ALK (E13:A20, variant 1) fusion gene in tumors from these two patients by using RACE-coupled PCR sequencing and RT-PCR. Notably, we first showed that enforced EML4-ALK expression significantly promoted the in vitro proliferation, clonogenic colony formation and apoptosis resistance in immortalized normal renal tubal epithelial cell HK2 and their in vivo outgrowth when injected into immunocompromised nude mice, and importantly, this pro-tumorigenic effect could be completely abolished by ALK-specific inhibitor Crizotinib, indicating the potential effectiveness of ALK-specific inhibitors in treating ALK-positive ccRCC patients. Our data show that ALK fusions exist in adult ccRCC, which provides the rationale for ALK inhibitor therapy in selected patients of ccRCC. Citation Format: Huafeng Wei, Yang Chen. Identification of anaplastic lymphoma kinase fusions in clear cell renal cell carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-109.

Abstract 677: EML4-ALK fusion gene expressing transgenic mouse for lung cancer model

Abstract Background: EML4-ALK is a fusion-type protein typrosin kinase that is generated in lung cancer. We have established transgenic mouse line. The surfactant protein C gene (SPC) is only expressed in alveolar epithelial cells. We applied SPC promoter on encoded human-EML4-ALK gene. Normally, EML4-ALK gene is silenced when LoxP-PGK-LoxP gene is turned on. When Cre recombinase is present with the specific inducer, tamoxifen, EML4-ALK gene is expressed in alveolar epithelial cell, and converses to lung cancer. Materials and Methods: For generation of EML4-ALK fusion transgenic mouse, a cDNA fragment encoding FLAG tagged EML4-ALK (variant 1) was ligated to end of the CMV-LoxP-PGK-LoxP. The expression cassette was injected into pronuclear-stage embryos of B6 mouse to generate Tg mouse. Transgenic mouse was prepared for interbreed with KI mouse (SPC-CreER2T-trTA-NeoR). The KI-Tg fusion mouse was confirmed by genotyping, then the mouse was injected with tamoxifen (cre recombinase inducer) intraperitoneally. The lung tumors were observed by MRI or CT. The lung pathology was analyzed by immunohistochemistry and hematoxylin & eosin staining. For confirmation of EML4-ALK protein expression, western blot was performed in different organs. EML4-ALK tumor-bearing mouse was treated with ALK tyrosine kinase inhibitor (TKI) for 2 weeks and tumor shrinkage was measured. Results: EML4-ALK tumor was observed after one week. Tumor nodules were widely observed in all lung lobes. Pathologically, the histologic type was adenocarcinoma and had homology to patient tissue on H&E stain. We confirmed EML4-ALK expression in different organs including lung, heart, liver, stomach, kidney, colon and brain. EML4-ALK (120kDa) was strongly expressed in lung, but not in other organs. Indeed, ALK and Flag expression were observed in tumor region by immunohistochemistry. The EML4-ALK tumor bearing mice were treated with ALK TKI for 2 weeks. The ALK TKI-treated mice showed dramatic shrinkage of tumors and showed gain in body weight. Conclusions: EML4-ALK Tg mouse was successfully established. The benefits of the model compared to a previous conditioned Tg mouse model are (1) no need to treat Cre inducer daily, and (2) short duration (approximately 1 week) of tumorigenesis. We confirmed dramatic tumor shrinkage after treatment with ALK TKI. This model provides a strong preclinical model for testing ALK TKIs in lung cancer. Citation Format: Kyoung-Ho Pyo, Hye Ryun Kim, Sun Min Lim, Mi Ran Yun, Sung-Moo Kim, Hwan Kim, Han Na Kang, Ji Min Lee, Sang Gyun Kim, Byoung Chul Cho. EML4-ALK fusion gene expressing transgenic mouse for lung cancer model. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 677.

Anaplastic lymphoma kinase aberrations correlate with metastatic features in pediatric rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is the most frequent soft tissue tumor in childhood and arises from immature mesenchymal cells committed to skeletal muscle differentiation. Anaplastic Lymphoma Kinase (ALK) is a receptor tyrosine kinase aberrantly expressed in several cancers. Moreover, ALK full-length receptor protein has been observed in RMS, although its clinical and functional significance is yet controversial. The role of ALK and its clinical relevance were investigated in a selected cohort of 74 FFPE pediatric RMS and a panel of RMS cell lines, evaluating its gene and protein status, utilizing Fluorescent In Situ Hybridization (FISH), immunohistochemistry (IHC) and Western blot approaches. Moreover, to get insight into its possible therapeutic relevance, effects of ALK silencing on cell proliferation, invasion and apoptosis were studied in RMS cells. ALK IHC positivity was significantly correlated with gene copy number gain, the alveolar subtype, PAX3/7-FOXO1 rearrangements, the presence of metastasis at diagnosis and a worse overall outcome. Furthermore, EML4-ALK fusion gene associated with higher protein expression was identified in an embryonal RMS. ALK silencing in RH30 ALK positive cells strongly inhibited invasion capability. Overall, our data suggest a potential role of ALK in pediatric RMS.

Custom Gene Capture and Next-Generation Sequencing to Resolve Discordant ALK Status by FISH and IHC in Lung Adenocarcinoma

IntroductionWe performed a genomic study in lung adenocarcinoma cases with discordant anaplastic lymphoma receptor tyrosine kinase gene (ALK) status by fluorescent in situ hybridization (FISH) and immunohistochemical (IHC) analysis. MethodsDNA from formalin-fixed paraffin-embedded tissues of 16 discordant (four FISH-positive/IHC–negative and 12 FISH-negative/IHC–positive) cases by Vysis ALK Break Apart FISH and ALK IHC testing (ALK1 clone) were subjected to whole gene capture and next-generation sequencing (NGS) of nine genes, including ALK, echinoderm microtubule associated protein like 4 gene (EML4), kinesin family member 5B gene (KIF5B), staphylococcal nuclease and tudor domain containing 1 gene (SND1), BRAF, ret proto-oncogene (RET), ezrin gene (EZR), ROS1, and telomerase reverse transcriptase (TERT). All discordant cases (except one FISH-negative/IHC–positive case without sufficient tissue) were analyzed by IHC with D5F3 antibody. In one case with fresh frozen tissue, whole transcriptome sequencing was also performed. Twenty-six concordant (16 FISH-positive/IHC–positive and 10 FISH-negative/IHC–negative) cases were included as controls. ResultsIn four ALK FISH-positive/IHC–negative cases, no EML4-ALK fusion gene was observed by NGS, but in one case using fresh frozen tissue, we identified EML4–baculoviral AIP repeat containing 6 gene (BIRC6) and AP2 associated kinase 1 gene (AAK1)-ALK fusion genes. Whole transcriptome sequencing revealed a highly expressed EML4-BIRC6 fusion transcript and a minimally expressed AAK1 transcript. Among the 12 FISH-negative/IHC–positive cases, no evidence of ALK gene rearrangement was detected by NGS. Eleven of 12 FISH-negative/IHC–positive cases detected by ALK1 clone were concordant by repeat ALK IHC with D5F3 antibody (i.e., FISH-negative/IHC–negative by D5F3 clone). Among the 16 ALK FISH-positive/IHC–positive positive controls, whole gene capture identified ALK gene fusion in 15 cases, including in one case with Huntington interacting protein 1 gene (HIP1)-ALK. No ALK fusion gene was observed in any of the 10 FISH-negative/IHC–negative cases. Other fusion genes involving ROS1, EZR, BRAF, and SND1 were also found. ConclusionsALK FISH results appeared to be false-positive in three of four FISH-positive/IHC–negative cases, whereas no false-negative ALK FISH case was identified among 12 ALK FISH-negative/IHC–positive cases by ALK1 clone, which was in keeping with the concordant FISH-negative/IHC–negative status by D5F3 clone. Our targeted whole gene capture approach using formalin-fixed paraffin embedded samples was effective for detecting rearrangements involving ALK and other actionable oncogenes.

Protocol Design for the Bench to Bed Trial in Alectinib-Refractory Non–Small-Cell Lung Cancer Patients Harboring the EML4-ALK Fusion Gene (ALRIGHT/OLCSG1405)

Based on our preclinical study results, which showed that the activation of the hepatocyte growth factor/MET pathway is a potential mechanism of acquired resistance to alectinib, we launched the ALRIGHT (OLCSG1405 [alectinib-refractory non–small-cell lung cancer patients harboring the EML4-ALK fusion gene]), a phase II trial of the anaplastic lymphoma kinase (ALK)/MET inhibitor crizotinib in patients with non–small-cell lung cancer refractory to alectinib and harboring the echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusion gene. Patients with ALK-rearranged tumors who have developed disease progression during alectinib treatment will receive crizotinib monotherapy until disease progression or the occurrence of unacceptable toxicity. The primary endpoint is set as the objective response rate, assuming that a response in 50% of eligible patients will indicate potential usefulness and that 15% would be the lower limit of interest (1-sided α of 0.05, β of 0.20). The estimated accrual number of patients is 9. The secondary endpoints include progression-free survival, overall survival, adverse events, and patient-reported outcomes. We will also take tissue samples before crizotinib monotherapy to conduct an exploratory analysis of ALK and hepatocyte growth factor/MET expression levels and gene alterations (eg, mutations, amplifications, and translocations). We will obtain information regarding whether crizotinib, which targets not only ALK, but also MET, can truly produce efficacy with acceptable safety profiles in ALK+ non–small-cell lung cancer even in the alectinib-refractory setting.

Correlation Analysis of EML4-ALK Fusion Gene Mutation and Clinical Features in Patients With Non-small Cell Lung Cancer

Correlation Analysis of EML4-ALK Fusion Gene Mutation and Clinical Features in Patients With Non-small Cell Lung Cancer

Bénéfice à l’évaluation moléculaire en routine pour les cancers bronchiques métastatiques

EGFR tyrosine kinase inhibitors and crizotinib are nowadays the optimal treatment for metastatic lung cancer with activation of EGFR mutations and ALK rearrangement. In addition, several targeted agents are in development for lung cancer with other oncodrivers. In France, since 2011, six oncodrivers are routinely tested in patients with stage IV. The aim of this study was to assess whether systematic detection of oncodrivers and matched targeted therapy improve overall survival in patients with advanced lung adenocarcinoma. This study included all consecutive patients treated in our department for advanced lung adenocarcinoma from January 2012 to December 2013. We studied the impact in survival according to the presence of the driver and the targeted therapy. Among the 261 patients included, oncodrivers alterations were found in 43.5% of patients: EML4-ALK fusion genes (2.1%), EGFR (10.3%), KRAS (27.7%), BRAF (2.5%), HER2 (0.8%), and PI3KCA (0.8%) mutations. Twenty-nine percent of patients (n=32) with oncodrivers received matched targeted therapy. Patient treated by targeted agent appropriate to an oncogenic driver had a median survival of 21.1 months (95% CI: 14.7-27.5). The patients (n=79) who did not receive targeted therapy had a median survival of 6.6 months (95% CI: 4.3-8.9). The patients (n=150) without identified driver had a median survival of 9.7 months (95% CI: 6.7-11.7); P<0.001. An actionable oncodriver was routinely detected in nearly half of patients with advanced lung adenocarcinoma. This systematic detection may influence treatment outcomes, notably with matched targeted therapy.

Non-Small Cell Lung Cancer Cells Acquire Resistance to the ALK Inhibitor Alectinib by Activating Alternative Receptor Tyrosine Kinases.

Crizotinib is the standard of care for advanced non-small cell lung cancer (NSCLC) patients harboring the anaplastic lymphoma kinase (ALK) fusion gene, but resistance invariably develops. Unlike crizotinib, alectinib is a selective ALK tyrosine kinase inhibitor (TKI) with more potent antitumor effects and a favorable toxicity profile, even in crizotinib-resistant cases. However, acquired resistance to alectinib, as for other TKIs, remains a limitation of its efficacy. Therefore, we investigated the mechanisms by which human NSCLC cells acquire resistance to alectinib. We established two alectinib-resistant cell lines that did not harbor the secondary ALK mutations frequently occurring in crizotinib-resistant cells. One cell line lost the EML4-ALK fusion gene, but exhibited increased activation of insulin-like growth factor-1 receptor (IGF1R) and human epidermal growth factor receptor 3 (HER3), and overexpressed the HER3 ligand neuregulin 1. Accordingly, pharmacologic inhibition of IGF1R and HER3 signaling overcame resistance to alectinib in this cell line. The second alectinib-resistant cell line displayed stimulated HGF autocrine signaling that promoted MET activation and remained sensitive to crizotinib treatment. Taken together, our findings reveal two novel mechanisms underlying alectinib resistance that are caused by the activation of alternative tyrosine kinase receptors rather than by secondary ALK mutations. These studies may guide the development of comprehensive treatment strategies that take into consideration the various approaches ALK-positive lung tumors use to withstand therapeutic insult.

Lung Adenocarcinoma with Anaplastic Lymphoma Kinase (ALK) Rearrangement Presenting as Carcinoma of Unknown Primary Site: Recognition and Treatment Implications.

BackgroundMolecular cancer classifier assays are being used with increasing frequency to predict tissue of origin and direct site-specific therapy for patients with carcinoma of unknown primary site (CUP).ObjectiveWe postulated some CUP patients predicted to have non-small-cell lung cancer (NSCLC) by molecular cancer classifier assay may have anaplastic lymphoma kinase (ALK) rearranged tumors, and benefit from treatment with ALK inhibitors.MethodsWe retrospectively reviewed CUP patients who had the 92-gene molecular cancer classifier assay (CancerTYPE ID; bioTheranostics, Inc.) performed on tumor biopsies to identify patients predicted to have NSCLC. Beginning in 2011, we have tested these patients for ALK rearrangements and epidermal growth factor receptor (EGFR) activating mutations, based on the proven therapeutic value of these targets in NSCLC. We identified CUP patients with predicted NSCLC who were subsequently found to have ALK rearrangements.ResultsNSCLC was predicted by the molecular cancer classifier assay in 37 of 310 CUP patients. Twenty-one of these patients were tested for ALK rearrangements, and four had an EML4-ALK fusion gene detected. The diagnosis of lung cancer was strongly suggested in only one patient prior to molecular testing. One patient received ALK inhibitor treatment and has had prolonged benefit.ConclusionsWe report on patients with lung adenocarcinoma and ALK rearrangements originally diagnosed as CUP who were identified using a molecular cancer classifier assay. Although ALK inhibitors treatment experience is limited, this newly identifiable group of lung cancer patients should be considered for therapy according to guidelines for stage IV ALK-positive NSCLC.

Haplotyping germline and cancer genomes with high-throughput linked-read sequencing.

Haplotyping of human chromosomes is a prerequisite for cataloguing the full repertoire of genetic variation. We present a microfluidics-based, linked-read sequencing technology that can phase and haplotype germline and cancer genomes using nanograms of input DNA. This high-throughput platform prepares barcoded libraries for short-read sequencing and computationally reconstructs long-range haplotype and structural variant information. We generate haplotype blocks in a nuclear trio that are concordant with expected inheritance patterns and phase a set of structural variants. We also resolve the structure of the EML4-ALK gene fusion in the NCI-H2228 cancer cell line using phased exome sequencing. Finally, we assign genetic aberrations to specific megabase-scale haplotypes generated from whole-genome sequencing of a primary colorectal adenocarcinoma. This approach resolves haplotype information using up to 100 times less genomic DNA than some methods and enables the accurate detection of structural variants.

Mutations of the EGFR, K-ras, EML4-ALK, and BRAF genes in resected pathological stage I lung adenocarcinoma.

The EGFR, K-ras, EML4-ALK, and BRAF genes are oncogenic drivers of lung adenocarcinoma. We conducted this study to analyze the mutations of these genes in stage I adenocarcinoma. The subjects of this retrospective study were 256 patients with resected stage I lung adenocarcinoma. We analyzed mutations of the EGFR, K-ras, and BRAF genes, and the EML4-ALK fusion gene. We also assessed disease-free survival (DFS) to evaluate the prognostic value and overall survival (OS) to evaluate the predictive value of treatment after recurrence. Mutations of the EGFR, K-ras, EML4-ALK, and BRAF genes were detected in 120 (46.8%), 14 (5.5%), 6 (2.3%), and 2 (0.8%) of the 256 tumors. Two tumors had double mutations (0.8%). The incidence of EGFR mutations was significantly higher in women than in men. The EML4-ALK fusion gene was detected only in younger patients. The DFS and OS of the K-ras mutant group were significantly worse than those of the EGFR mutant group, the EML4-ALK fusion gene group, and the wild-type group. Six of the seven patients with the EML4-ALK fusion gene are still alive without recurrent disease. In patients with stage I adenocarcinoma, mutation of the K-ras gene was a poor prognostic factor for recurrence. The presence of a mutation of the EGFR or EML4-ALK gene was not a prognostic factor.

Genetic alterations in lung adenocarcinoma with a micropapillary component.

Pulmonary adenocarcinoma (PA) with a micropapillary component (PA-MPC) is known as an aggressive subtype of PA. The molecular profiles of PA-MPC have not been well characterized. the pathological reports of patients who underwent surgical resection for lung cancer between April, 2004 and May, 2012 were reviewed. Of the 674 patients diagnosed with PA, 28 were found to have MPC. A total of 138 resected PAs without MPC were selected in the same period to serve as age-, gender- and smoking status-matched controls to the PA-MPC group. Mutational status was determined by the following two methods: SNaPshot assay based on multiplex polymerase chain reaction (PCR), primer extension and capillary electrophoresis that was designed to assess 38 somatic mutations in 8 genes [AKT1, BRAF, endothelial growth factor receptor (EGFR), Kirsten rat sarcoma viral oncogene homolog (KRAS), mitogen-activated protein kinase kinase 1, neuroblastoma RAS viral oncogene homolog, phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit α (PIK3CA) and phosphatase and tensin homolog]; and a PCR-based sizing assay that assesses EGFR exon 19 (deletions), EGFR exon 20 (insertions) and human epidermal growth factor receptor 2 exon 20 (insertions). echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase fusion gene (EML4-ALK) was screened by ALK immunohistochemistry and confirmed using the reverse transcription PCR assay and the break-apart fluorescence in situ hybridization assay. Regarding genetic alterations, 13 (46.4%) of the 28 PA-MPCs harbored mutually exclusive mutations: 9 (32.1%) EGFR mutations, 1 (3.6%) KRAS mutation and 3 (10.7%) EML4-ALK fusion genes. PAs without MPC harbored 42 (30.4%) EGFR mutations, 17 (12.3%) KRAS mutations, 3 (2.2%) EML4-ALK fusion genes and 1 (0.7%) PIK3CA mutation. EML4-ALK fusion genes appeared to occur significantly more frequently in PA-MPCs compared with PAs without MPC (P=0.027). Although the sample size was small, our study suggests that the molecular pathogenesis of PA-MPC may be different from that of other adenocarcinomas.

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.

P3-1-56 - Outcome of two patients harboring EML4-ALK fusion gene with brain metastasis treated with crizotinib

P3-1-56 - Outcome of two patients harboring EML4-ALK fusion gene with brain metastasis treated with crizotinib

Induction of PD-L1 Expression by the EML4-ALK Oncoprotein and Downstream Signaling Pathways in Non-Small Cell Lung Cancer.

Therapies targeted to the immune checkpoint mediated by PD-1 and PD-L1 show antitumor activity in a subset of patients with non-small cell lung cancer (NSCLC). We have now examined PD-L1 expression and its regulation in NSCLC positive for the EML4-ALK fusion gene. The expression of PD-L1 at the protein and mRNA levels in NSCLC cell lines was examined by flow cytometry and by reverse transcription and real-time PCR analysis, respectively. The expression of PD-L1 in 134 surgically resected NSCLC specimens was evaluated by immunohistochemical analysis. The PD-L1 expression level was higher in NSCLC cell lines positive for EML4-ALK than in those negative for the fusion gene. Forced expression of EML4-ALK in Ba/F3 cells markedly increased PD-L1 expression, whereas endogenous PD-L1 expression in EML4-ALK-positive NSCLC cells was attenuated by treatment with the specific ALK inhibitor alectinib or by RNAi with ALK siRNAs. Furthermore, expression of PD-L1 was downregulated by inhibitors of the MEK-ERK and PI3K-AKT signaling pathways in NSCLC cells positive for either EML4-ALK or activating mutations of the EGFR. Finally, the expression level of PD-L1 was positively associated with the presence of EML4-ALK in NSCLC specimens. Our findings that both EML4-ALK and mutant EGFR upregulate PD-L1 by activating PI3K-AKT and MEK-ERK signaling pathways in NSCLC reveal a direct link between oncogenic drivers and PD-L1 expression.

Abstract 5122: In vivo imaging models of bone and brain metastases and pleural carcinomatosis developed using a novel human EML4-ALK lung cancer cell line, A925LPE3

Abstract Introduction:EML4-ALK lung cancer accounts for approximately 3%-7% of non-small cell lung cancer cases. Crizotinib, an ALK tyrosine kinase inhibitor, shows dramatic clinical efficacy with a response rate of approximately 60%-80% in EML4-ALK NSCLC patients. However, almost all patients who strongly responded to crizotinib acquired resistance over time. Recently, new generation ALK-TKIs such as alectinib and ceritinib have been approved for treatment of ALK-rearranged NSCLC patients, and it is now clear that resistance may also develop against this class of inhibitors. To investigate the molecular mechanism underlying tumor progression and targeted drug sensitivity/resistance in EML4-ALK lung cancer, clinically relevant animal models are indispensable. Methods: A human lung adenocarcinoma cell line A925L, which expresses an EML4-ALK gene fusion (variant 5a, E2:A20), established from a surgical specimen obtained from a Japanese male patient. We further established highly tumorigenic A925LPE3 cells with luciferase gene transfection, which also have the EML4-ALK gene fusion. A925LPE3 cells were injected into the right thoracic cavity for the pleural carcinomatosis model, into the tibia for the bone metastasis model, and into the right striatum for the brain metastasis model. After inoculation, the quantity of tumors and the quality of bones were tracked in live mice by repeated noninvasive optical imaging of tumor-specific luciferase activity using the IVIS Lumina XR Imaging System. Results: In this study, we found that A925L and A925LPE3 cell lines are sensitive to the ALK inhibitors crizotinib and alectinib. By using A925LPE3 cells we established in vivo imaging models for pleural carcinomatosis, bone metastasis, and brain metastasis, all of which are significant clinical concerns of advanced EML4-ALK lung cancer. Interestingly, crizotinib caused tumors to shrink in the pleural carcinomatosis model, but not in bone and brain metastasis models, while alectinib showed remarkable efficacy in all three models, indicative of the clinical efficacy of these ALK inhibitors. Conclusions: Our in vivo imaging models of multiple organ sites may provide useful resources to analyze further the pathogenesis of EML4-ALK lung cancer and its response and resistance to ALK inhibitors in various organ microenvironments. Citation Format: Shigeki Nanjo, Shinji Takeuchi, Kenji Kita, Koji Fukuda, Mitsutoshi Nakada, Hiroshi Nishihara, Seiji Yano. In vivo imaging models of bone and brain metastases and pleural carcinomatosis developed using a novel human EML4-ALK lung cancer cell line, A925LPE3. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5122. doi:10.1158/1538-7445.AM2015-5122