Inhibition of ALK, PI3K/MEK, and HSP90 in murine lung adenocarcinoma induced by EML4-ALK fusion oncogene

EML4-ALK fusions drive lung adeno-to-squamous transition through JAK-STAT activation

Human lung adenosquamous cell carcinoma (LUAS), containing both adenomatous and squamous pathologies, exhibits strong cancer plasticity. We find that ALK rearrangement is detectable in 5.1-7.5% of human LUAS, and transgenic expression of EML4-ALK drives lung adenocarcinoma (LUAD) formation initially and squamous transition at late stage. We identify club cells as the main cell-of-origin for squamous transition. Through recapitulating lineage transition in organoid system, we identify JAK-STAT signaling, activated by EML4-ALK phase separation, significantly promotes squamous transition. Integrative study with scRNA-seq and immunostaining identify a plastic cell subpopulation in ALK-rearranged human LUAD showing squamous biomarker expression. Moreover, those relapsed ALK-rearranged LUAD show notable upregulation of squamous biomarkers. Consistently, mouse squamous tumors or LUAD with squamous signature display certain resistance to ALK inhibitor, which can be overcome by combined JAK1/2 inhibitor treatment. This study uncovers strong plasticity of ALK-rearranged tumors in orchestrating phenotypic transition and drug resistance and proposes a potentially effective therapeutic strategy.

Two case reports: EML4-ALK rearrangement large cell neuroendocrine carcinoma and literature review

Anaplastic lymphoma kinase gene (ALK) rearrangement is present in only approximately 5% of non-small cell lung cancers (NSCLCs) and is scarce in LCNEC patients. The conventional first-line treatment options are chemotherapy combined with immunotherapy or chemotherapy followed by palliative radiotherapy. In this report, we present two cases of metastatic LCNEC with EML4-ALK fusion that were treated with ALK-TKI inhibitors and demonstrated a rapid therapeutic response. Both patients were nonsmoking women who declined cytotoxic chemotherapy, underwent Next-Generation Sequencing (NGS), and confirmed EML4-ALK fusion. They were treated with alectinib as first-line therapy, and the tumors showed significant shrinkage after two months, achieving a PR (defined as a more than 30% decrease in the sum of maximal dimensions). The PFS was 22 months and 32 months, respectively, until the last follow-up. A systematic review of all previously reported cases of LCNEC with ALK mutations identified only 21 cases. These cases were characterized by being female (71.4%), nonsmoking (85.7%), diagnosed at a relatively young age (median age 51.1), and stage IV (89.5%), with an overall response rate (ORR) of 90.5%. PFS and OS were significantly longer than those treated with conventional chemotherapy/immunotherapy. Based on the clinical characteristics and the effective therapeutic outcomes with ALK inhibitors in LCNEC patients with ALK fusion, we recommend routine ALK IHC (economical, affordable, and convenient, but with higher false positives) as a screening method in advanced LCNEC patients, particularly nonsmoking females or those who are not candidates for or unwilling to undergo cytotoxic chemotherapy. Further molecular profiling is necessary to confirm these potential beneficiaries. We suggest TKI inhibitors as the first-line treatment for metastatic LCNEC with ALK fusion. Additional studies on larger cohorts are required to assess the prevalence of ALK gene fusions and their sensitivity to various ALK inhibitors.

Management of Oncogene Driven Locally Advanced Unresectable Non-small Cell Lung Cancer

INTRODUCTION

The current standard of care of locally advanced non-small cell lung cancer (LA-NSCLC) is concurrent chemoradiation, followed by consolidation durvalumab. However, there is evidence that the efficacy of chemoradiation and also immunotherapy in many oncogene-positive LA-NSCLC are attenuated, and dependent on the subgroup.

AREAS COVERED

We will firstly review the outcomes of standard-of-care therapy in oncogene-driven LA-NSCLC. We looked at various oncogene driven subgroups and the tumor microenvironment that may explain differential response. Finally, we review the role of targeted therapy in the treatment of LA-NSCLC.

EXPERT OPINION

Each oncogene-positive subgroup should be treated as its own entity, and continued efforts should be undertaken to incorporate targeted therapy, which is likely to yield superior survival outcomes if trial design can be optimized and toxicities can be managed.

Current status and challenges of immunotherapy in ALK rearranged NSCLC

Rearrangements of the anaplastic lymphoma kinase (ALK) gene account for 5-6% in non-small cell lung cancer (NSCLC). ALK rearranged NSCLC is sensitive to ALK tyrosine kinase inhibitors (TKIs) but prone to drug resistance. Meanwhile, ALK rearranged NSCLC has poor response to single immunotherapy. Here we mainly describe the immune escape mechanisms of ALK mutated NSCLC and the role of related biomarkers. Additionally, we collate and evaluate preclinical and clinical studies of novel immune combination regimens, and describe the prospects and perspectives for the in vivo application of novel immune technologies in patients with ALK rearranged NSCLC.

Alternative Treatment Options to ALK Inhibitor Monotherapy for EML4-ALK-Driven Lung Cancer

EML4-ALK is an oncogenic fusion protein that accounts for approximately 5% of NSCLC cases. Targeted inhibitors of ALK are the standard of care treatment, often leading to a good initial response. Sadly, some patients do not respond well, and most will develop resistance over time, emphasizing the need for alternative treatments. This review discusses recent advances in our understanding of the mechanisms behind EML4-ALK-driven NSCLC progression and the opportunities they present for alternative treatment options to ALK inhibitor monotherapy. Targeting ALK-dependent signalling pathways can overcome resistance that has developed due to mutations in the ALK catalytic domain, as well as through activation of bypass mechanisms that utilise the same pathways. We also consider evidence for polytherapy approaches that combine targeted inhibition of these pathways with ALK inhibitors. Lastly, we review combination approaches that use targeted inhibitors of ALK together with chemotherapy, radiotherapy or immunotherapy. Throughout this article, we highlight the importance of alternative breakpoints in the EML4 gene that result in the generation of distinct EML4-ALK variants with different biological and pathological properties and consider monotherapy and polytherapy approaches that may be selective to particular variants.

Role of STK11 in ALK‑positive non‑small cell lung cancer (Review)

Anaplastic lymphoma kinase (ALK) inhibitors have been shown to be effective in treating patients with ALK-positive non-small cell lung cancer (NSCLC), and crizotinib, ceritinib and alectinib have been approved as clinical first-line therapeutic agents. The availability of these inhibitors has also largely changed the treatment strategy for advanced ALK-positive NSCLC. However, patients still inevitably develop resistance to ALK inhibitors, leading to tumor recurrence or metastasis. The most critical issues that need to be addressed in the current treatment of ALK-positive NSCLC include the high cost of targeted inhibitors and the potential for increased toxicity and resistance to combination therapy. Recently, it has been suggested that the serine/threonine kinase 11 (STK11) mutation may serve as one of the biomarkers for immunotherapy in NSCLC. Therefore, the main purpose of this review was to summarize the role of STK11 in ALK-positive NSCLC. The present review also summarizes the treatment and drug resistance studies in ALK-positive NSCLC and the current status of STK11 research in NSCLC.

A Polytherapy Strategy Using Vincristine and ALK Inhibitors to Sensitise EML4-ALK-Positive NSCLC

The oncogenic fusion of EML4-ALK is present in about 4-6% of non-small cell lung cancer (NSCLC). A targeted approach with ALK tyrosine kinase inhibitors (TKIs) has been proven highly effective in ALK-positive NSCLC patients. However, despite the initial responses, the outcome of the treatment is variable. Previous studies have shown that the differential response depends in part on the type of EML4-ALK variant. Here, we examined the combination of ALK inhibitors and microtubule poison, vincristine, in cells expressing EML4-ALK V1 and V3, the two most common variants in NSCLC. We showed that combination therapy of ALK-TKIs with vincristine had anti-proliferative effects and blocked RAS/MAPK, PI3K/AKT and JAK/STAT3 signalling pathways in EML4-ALK V1 but not V3 cells. Our results demonstrate that high levels of tubulin acetylation are associated with poor response to vincristine in EML4-ALK V3 cells. Additionally, we demonstrated differences in microtubule stability between the two EML4-ALK fusions. EML4-ALK V3 cells exhibited dynamic microtubules that confer poor response to vincristine compared to V1 cells. Hence, we suggested that the portion of EML4 in the fusion has an important role for the outcome of the combination treatment.

A new ALK inhibitor overcomes resistance to first- and second-generation inhibitors in NSCLC

More than 60% of nonsmall cell lung cancer (NSCLC) patients show a positive response to the first ALK inhibitor, crizotinib, which has been used as the standard treatment for newly diagnosed patients with ALK rearrangement. However, most patients inevitably develop crizotinib resistance due to acquired secondary mutations in the ALK kinase domain, such as the gatekeeper mutation L1196M and the most refractory mutation, G1202R. Here, we develop XMU-MP-5 as a new-generation ALK inhibitor to overcome crizotinib resistance mutations, including L1196M and G1202R. XMU-MP-5 blocks ALK signaling pathways and inhibits the proliferation of cells harboring either wild-type or mutant EML4-ALK in vitro and suppresses tumor growth in xenograft mouse models in vivo. Structural analysis provides insights into the mode of action of XMU-MP-5. In addition, XMU-MP-5 induces significant regression of lung tumors in two genetically engineered mouse (GEM) models, further demonstrating its pharmacological efficacy and potential for clinical application. These preclinical data support XMU-MP-5 as a novel selective ALK inhibitor with high potency and selectivity. XMU-MP-5 holds great promise as a new therapeutic against clinically relevant secondary ALK mutations.

Preclinical Models for the Study of Lung Cancer Pathogenesis and Therapy Development

Experimental preclinical models have been a cornerstone of lung cancer translational research. Work in these model systems has provided insights into the biology of lung cancer subtypes and their origins, contributed to our understanding of the mechanisms that underlie tumor progression, and revealed new therapeutic vulnerabilities. Initially patient-derived lung cancer cell lines were the main preclinical models available. The landscape is very different now with numerous preclinical models for research each with unique characteristics. These include genetically engineered mouse models (GEMMs), patient-derived xenografts (PDXs) and three-dimensional culture systems ("organoid" cultures). Here we review the development and applications of these models and describe their contributions to lung cancer research.

Failure to Guard: Mitochondrial Protein Quality Control in Cancer

Mitochondria are energetic and dynamic organelles with a crucial role in bioenergetics, metabolism, and signaling. Mitochondrial proteins, encoded by both nuclear and mitochondrial DNA, must be properly regulated to ensure proteostasis. Mitochondrial protein quality control (MPQC) serves as a critical surveillance system, employing different pathways and regulators as cellular guardians to ensure mitochondrial protein quality and quantity. In this review, we describe key pathways and players in MPQC, such as mitochondrial protein translocation-associated degradation, mitochondrial stress responses, chaperones, and proteases, and how they work together to safeguard mitochondrial health and integrity. Deregulated MPQC leads to proteotoxicity and dysfunctional mitochondria, which contributes to numerous human diseases, including cancer. We discuss how alterations in MPQC components are linked to tumorigenesis, whether they act as drivers, suppressors, or both. Finally, we summarize recent advances that seek to target these alterations for the development of anti-cancer drugs.

Autophagy-related genes serve as heat shock protein 90 co-chaperones in disease resistance against cassava bacterial blight

Heat shock protein 90 (HSP90) is involved in plant growth and various stress responses via regulating protein homeostasis. Autophagy keeps cellular homeostasis by recycling the components of cellular cytoplasmic constituents. Although they have similar effects on cellular protein homeostasis, the direct association between HSP90 and autophagy signaling remains unclear in plants, especially in tropical crops. In this study, the correlation between HSP90 and autophagy signaling was systematically analyzed by protein-protein interaction in cassava, one of the most important economy fruit in tropic. In addition, their effects on plant disease response and underlying mechanisms in cassava were investigated by functional genomics and genetic phenotype assay. The potential MeHSP90.9-MeSGT1-MeRAR1 chaperone complex interacts with MeATGs and subsequently triggers autophagy signaling, conferring improved disease resistance to cassava bacterial blight (CBB). On the contrary, HSP90 inhibitor and autophagy inhibitor decreased disease resistance against CBB in cassava, and autophagy may be involved in the potential MeHSP90.9-MeSGT1-MeRAR1 chaperone complex-mediated multiple immune responses. This study highlights the precise modulation of autophagy signaling by potential MeHSP90.9-MeSGT1-MeRAR1 chaperone complex in autophagy-mediated disease resistance to CBB.

ALK-positive non-small cell lung cancer; potential combination drug treatments

Advances in chromosomally rearranged ALK positive non-small cell lung cancer have been dramatic in only the last few years. Survival times have improved dramatically due to the introduction of ever more efficacious ALK inhibitors. These improvements have been due largely to improvements in blood-brain barrier penetration and the breadth of ligand binding pocket mutations against which the drugs are effective. However, the advances maybe slow as compared to the frequency of cancers with compound resistance mutations are appearing, suggesting the need to develop multiple ALK inhibitors to target different compound mutations.Another research area that promises to provide further gains is the use of drug combinations, with an ALK inhibitor combined with a drug targeting a "second driver" to overcome resistance. In this review, the range of secondary targets for ALK+ lung cancer and the potential for their clinical success are reviewed.

EML4-ALK-mediated activation of the JAK2-STAT pathway is critical for non-small cell lung cancer transformation

BACKGROUND

The echinoderm microtubule-associated protein-like-4 anaplastic lymphoma kinase (EML4-ALK) fusion gene was identified in a subset of non-small cell lung cancer (NSCLC) patients. They responded positively to ALK inhibitors. This study aimed to characterize the mechanisms triggered by EML4-ALK to induce NSCLC transformation.

METHODS

HEK293 and NIH3T3 cells were transfected with EML4-ALK variant 3 or pcDNA3.1-NC. H2228 cells were transfected with siRNA-EML4-ALK or siRNA-NC. Cell viability and proliferation were measured by the CCK-8 and EdU methods, respectively. Flow cytometry revealed apoptosis. Gene expression profiles were generated from a signaling pathway screen in EML4-ALK-regulated lung cancer cells and verified by qPCR and Western blotting. The co-immunoprecipitation and immunohistochemistry/ immunofluorescence determined the interaction and colocalization of JAK2-STAT pathway components with EML4-ALK.

RESULTS

Microarray identified several genes involved in the JAK2-STAT pathway. JAK2 and STAT6 were constitutively phosphorylated in H2228 cells. EML4-ALK silencing downregulated phosphorylation of STAT6. Expression of EML4-ALK in HEK293 and NIH3T3 cells activated JAK2, STAT1, STAT3, STAT5, and STAT6. In EML4-ALK-transfected HEK293 cells and EML4-ALK-positive H2228 cells, activated STAT6 and JAK2 colocalized with ALK. STAT3 and STAT6 were phosphorylated and translocated to the nucleus of H2228 cells following IL4 or IL6 treatment. Apoptosis increased, while cell proliferation and DNA replication decreased in H2228 cells following EML4-ALK knockdown. In contrast, HEK293 cell viability increased following EML4-ALK overexpression, while H2228 cell viability significantly decreased after treatment with ALK or JAK-STAT pathway inhibitors.

CONCLUSIONS

Our data suggest that the aberrant expression of EML4-ALK leads to JAK2-STAT signaling pathway activation, which is essential for the development of non-small cell lung cancer.

Small molecules in targeted cancer therapy: advances, challenges, and future perspectives

Due to the advantages in efficacy and safety compared with traditional chemotherapy drugs, targeted therapeutic drugs have become mainstream cancer treatments. Since the first tyrosine kinase inhibitor imatinib was approved to enter the market by the US Food and Drug Administration (FDA) in 2001, an increasing number of small-molecule targeted drugs have been developed for the treatment of malignancies. By December 2020, 89 small-molecule targeted antitumor drugs have been approved by the US FDA and the National Medical Products Administration (NMPA) of China. Despite great progress, small-molecule targeted anti-cancer drugs still face many challenges, such as a low response rate and drug resistance. To better promote the development of targeted anti-cancer drugs, we conducted a comprehensive review of small-molecule targeted anti-cancer drugs according to the target classification. We present all the approved drugs as well as important drug candidates in clinical trials for each target, discuss the current challenges, and provide insights and perspectives for the research and development of anti-cancer drugs.

Combining radiotherapy with targeted therapies in non-small cell lung cancer: focus on anti-EGFR, anti-ALK and anti-angiogenic agents

The combination of radiotherapy (RT) with targeted agents in non-small cell lung cancer (NSCLC) has been expected to improve the therapeutic ratio and tumor control. The EGFR blockade enhances the antitumor effect of RT. The ALK inhibition elicits anti-proliferative, pro-apoptotic and antiangiogenic effects in ALK-positive NSCLC cell lines, enhanced by the exposure to RT. The antiangiogenic agents normalize pathological tumor vessels, thus decrease tumor cell hypoxia and improve radiosensitivity. To date, however, none of the targeted agents combined with RT has shown proven clinical benefit over standard chemoradiation (CRT) in locally advanced NSCLC. The risk of potential excessive toxicity related to the therapeutic combination of RT and targeted agents cannot be ignored. Well-designed clinical trials may allow development of more effective combination strategies. Another potential application of combined RT and targeted therapies in oncogene-driven NSCLC is metastatic oligoprogressive or oligopersistent disease. The use of RT in oligoprogressive oncogene-driven NSCLC, while continuing first line targeted therapy, can potentially eradicate resistant cell clones and provide survival benefit. Likewise, the consolidation of oligopersistent foci (molecularly resistant to first line targeted therapy) may potentially interfere with the natural course of the disease by avoiding or delaying progression. We discuss here the molecular and radiobiological mechanisms of combining RT and targeted agents, and summarize current clinical experience.

Heat shock protein 90 co-chaperone modules fine-tune the antagonistic interaction between salicylic acid and auxin biosynthesis in cassava

Heat shock protein 90 (HSP90) is an important molecular chaperone in plants. However, HSP90-mediated plant immune response remains elusive in cassava. In this study, cassava bacterial blight (CBB) induces the expression of MeHsf8, which directly targets MeHSP90.9 to activate its expression and immune response. Further identification of SHI-related sequence 1 (MeSRS1) and MeWRKY20 as MeHSP90.9 co-chaperones revealed the underlying mechanism of MeHSP90.9-mediated immune response. MeHSP90.9 interacts with MeSRS1 and MeWRKY20 to promote their transcriptional activation of salicylic acid (SA) biosynthetic gene avrPphB Susceptible 3 (MePBS3) and tryptophan metabolic gene N-acetylserotonin O-methyltransferase 2 (MeASMT2), respectively, so as to activate SA biosynthesis but inhibit tryptophan-derived auxin biosynthesis. Notably, genetic experiments confirmed that overexpressing MePBS3 and MeASMT2 could rescue the effects of silencing MeHsf8-MeHSP90.9 on disease resistance. This study highlights the dual regulation of SA and auxin biosynthesis by MeHSP90.9, providing the mechanistic understanding of MeHSP90.9 client partners in plant immunity.

EML4-ALK V3 oncogenic fusion proteins promote microtubule stabilization and accelerated migration through NEK9 and NEK7

EML4-ALK is an oncogenic fusion present in ∼5% of non-small cell lung cancers. However, alternative breakpoints in the EML4 gene lead to distinct variants of EML4-ALK with different patient outcomes. Here, we show that, in cell models, EML4-ALK variant 3 (V3), which is linked to accelerated metastatic spread, causes microtubule stabilization, formation of extended cytoplasmic protrusions and increased cell migration. EML4-ALK V3 also recruits the NEK9 and NEK7 kinases to microtubules via the N-terminal EML4 microtubule-binding region. Overexpression of wild-type EML4, as well as constitutive activation of NEK9, also perturbs cell morphology and accelerates migration in a microtubule-dependent manner that requires the downstream kinase NEK7 but does not require ALK activity. Strikingly, elevated NEK9 expression is associated with reduced progression-free survival in EML4-ALK patients. Hence, we propose that EML4-ALK V3 promotes microtubule stabilization through NEK9 and NEK7, leading to increased cell migration. This represents a novel actionable pathway that could drive metastatic disease progression in EML4-ALK lung cancer.

CXCR7 Reactivates ERK Signaling to Promote Resistance to EGFR Kinase Inhibitors in NSCLC

Although EGFR mutant-selective tyrosine kinase inhibitors (TKI) are clinically effective, acquired resistance can occur by reactivating ERK. We show using in vitro models of acquired EGFR TKI resistance with a mesenchymal phenotype that CXCR7, an atypical G protein-coupled receptor, activates the MAPK-ERK pathway via β-arrestin. Depletion of CXCR7 inhibited the MAPK pathway, significantly attenuated EGFR TKI resistance, and resulted in mesenchymal-to-epithelial transition. CXCR7 overexpression was essential in reactivation of ERK1/2 for the generation of EGFR TKI-resistant persister cells. Many patients with non-small cell lung cancer (NSCLC) harboring an EGFR kinase domain mutation, who progressed on EGFR inhibitors, demonstrated increased CXCR7 expression. These data suggest that CXCR7 inhibition could considerably delay and prevent the emergence of acquired EGFR TKI resistance in EGFR-mutant NSCLC. SIGNIFICANCE: Increased expression of the chemokine receptor CXCR7 constitutes a mechanism of resistance to EGFR TKI in patients with non-small cell lung cancer through reactivation of ERK signaling.

Targeting ALK in Cancer: Therapeutic Potential of Proapoptotic Peptides

ALK is a receptor tyrosine kinase, associated with many tumor types as diverse as anaplastic large cell lymphomas, inflammatory myofibroblastic tumors, breast and renal cell carcinomas, non-small cell lung cancer, neuroblastomas, and more. This makes ALK an attractive target for cancer therapy. Since ALK–driven tumors are dependent for their proliferation on the constitutively activated ALK kinase, a number of tyrosine kinase inhibitors have been developed to block tumor growth. While some inhibitors are under investigation in clinical trials, others are now approved for treatment, notably in ALK-positive lung cancer. Their efficacy is remarkable, however limited in time, as the tumors escape and become resistant to the treatment through different mechanisms. Hence, there is a pressing need to target ALK-dependent tumors by other therapeutic strategies, and possibly use them in combination with kinase inhibitors. In this review we will focus on the therapeutic potential of proapoptotic ALK-derived peptides based on the dependence receptor properties of ALK. We will also try to make a non-exhaustive list of several alternative treatments targeting ALK-dependent and independent signaling pathways.

Tandem Affinity Purification and Mass Spectrometry (TAP-MS) for the Analysis of Protein Complexes

Affinity purification followed by mass spectrometry has become the technique of choice to identify binding partners in biochemical complexes isolated from a physiologic cellular context. In this report we detail our protocol for tandem affinity purification (TAP) primarily based on the use of the FLAG and HA peptide epitopes, with a particular emphasis on factors affecting yield and specificity, as well as steps to implement an automated version of the TAP procedure. © 2019 by John Wiley & Sons, Inc.

Autochthonous murine models for the study of smoker and never-smoker associated lung cancers

Lung cancer accounts for the greatest number of cancer deaths in the world. Tobacco smoke-associated cancers constitute the majority of lung cancer cases but never-smoker cancers comprise a significant and increasing fraction of cases. Recent genomic and transcriptomic sequencing efforts of lung cancers have revealed distinct sets of genetic aberrations of smoker and never-smoker lung cancers that implicate disparate biology and therapeutic strategies. Autochthonous mouse models have contributed greatly to our understanding of lung cancer biology and identified novel therapeutic targets and strategies in the era of targeted therapy. With the emergence of immuno-oncology, mouse models may continue to serve as valuable platforms for novel biological insights and therapeutic strategies. Here, we will review the variety of available autochthonous mouse models of lung cancer, their relation to human smoker and never-smoker lung cancers, and their application to immuno-oncology and immune checkpoint blockade that is revolutionizing lung cancer therapy.

FGFR3-TACC3 is an oncogenic fusion protein in respiratory epithelium

Structural rearrangements of the genome can drive lung tumorigenesis through the generation of fusion genes with oncogenic properties. Advanced genomic approaches have identified the presence of a genetic fusion between fibroblast growth factor receptor 3 (FGFR3) and transforming acidic coiled-coil 3 (TACC3) in non-small cell lung cancer (NSCLC), providing a novel target for FGFR inhibition. To interrogate the functional consequences of the FGFR3-TACC3 fusion in the transformation of lung epithelial cells, we generated a novel transgenic mouse model that expresses FGFR3-TACC3 concomitant with loss of the p53 tumor suppressor gene. Intra-nasal delivery of an Ad5-CMV-Cre virus promoted seromucinous glandular transformation of olfactory cells lining the nasal cavities of FGFR3-TACC3 (LSL-F3T3) mice, which was further accelerated upon loss of p53 (LSL-F3T3/p53). Surprisingly, lung tumors failed to develop in intra-nasally infected LSL-F3T3 and LSL-F3T3/p53 mice. In line with these observations, we demonstrated that intra-nasal delivery of Ad5-CMV-Cre induces widespread Cre-mediated recombination in the olfactory epithelium. Intra-tracheal delivery of Ad5-CMV-Cre into the lungs of LSL-F3T3 and LSL-F3T3/p53 mice however, resulted in the development of lung adenocarcinomas. Taken together, these findings provide in vivo evidence for an oncogenic function of FGFR3-TACC3 in respiratory epithelium.

An EGFR ligand promotes EGFR-mutant but not KRAS-mutant lung cancer in vivo

EGFR ligands (e.g., EGF and TGFA) have been shown to be clinically associated with poor survival in lung cancer. Since TGFA itself initiates autochthonous tumors in liver, breast, and pancreas but not in the lung in transgenic mice in vivo, it would appear that an EGFR ligand may not initiate but rather promote lung cancer. However, it has not been proven in vivo whether lung cancer is promoted by an EGFR ligand. Using transgenic mouse models conditionally expressing EGFR^L858R or Kras^G12D with TGFA (an EGFR ligand) in lung epithelium, we determined that TGFA promoted the growth of EGFR^L858R-lung tumors in airway regions but not that of Kras^G12D-lung tumors. Analysis of TCGA datasets identified ΔNp63 and AGR2 as potential key tumor-promoting regulators, which were highly induced in the TGFA-induced EGFR^L858R-lung tumors. The expression of AGR2 was positively correlated with the expression of TGFA in human EGFR-mutant lung adenocarcinomas. The expression of TGFA in human EGFR-mutant lung adenocarcinomas but not in the EGFR wild-type lung adenocarcinoma was associated with poor survival. These results suggest that targeting EGFR ligands may benefit patients who carry EGFR-mutant lung tumors but will not benefit patients with KRAS-mutant lung tumors.

Kinase inhibitors: the road ahead

Receptor tyrosine kinase signalling pathways have been successfully targeted to inhibit proliferation and angiogenesis for cancer therapy. However, kinase deregulation has been firmly demonstrated to play an essential role in virtually all major disease areas. Kinase inhibitor drug discovery programmes have recently broadened their focus to include an expanded range of kinase targets and therapeutic areas. In this Review, we provide an overview of the novel targets, biological processes and disease areas that kinase-targeting small molecules are being developed against, highlight the associated challenges and assess the strategies and technologies that are enabling efficient generation of highly optimized kinase inhibitors.

The function and therapeutic targeting of anaplastic lymphoma kinase (ALK) in non-small cell lung cancer (NSCLC)

Lung cancer is the leading cause of death by cancer in North America. A decade ago, genomic rearrangements in the anaplastic lymphoma kinase (ALK) receptor tyrosine kinase were identified in a subset of non-small cell lung carcinoma (NSCLC) patients. Soon after, crizotinib, a small molecule ATP-competitive ALK inhibitor was proven to be more effective than chemotherapy in ALK-positive NSCLC patients. Crizotinib and two other ATP-competitive ALK inhibitors, ceritinib and alectinib, are approved for use as a first-line therapy in these patients, where ALK rearrangement is currently diagnosed by immunohistochemistry and in situ hybridization. The clinical success of these three ALK inhibitors has led to the development of next-generation ALK inhibitors with even greater potency and selectivity. However, patients inevitably develop resistance to ALK inhibitors leading to tumor relapse that commonly manifests in the form of brain metastasis. Several new approaches aim to overcome the various mechanisms of resistance that develop in ALK-positive NSCLC including the knowledge-based alternate and successive use of different ALK inhibitors, as well as combined therapies targeting ALK plus alternative signaling pathways. Key issues to resolve for the optimal implementation of established and emerging treatment modalities for ALK-rearranged NSCLC therapy include the high cost of the targeted inhibitors and the potential of exacerbated toxicities with combination therapies.

Suppression of Adaptive Responses to Targeted Cancer Therapy by Transcriptional Repression

Acquired drug resistance is a major factor limiting the effectiveness of targeted cancer therapies. Targeting tumors with kinase inhibitors induces complex adaptive programs that promote the persistence of a fraction of the original cell population, facilitating the eventual outgrowth of inhibitor-resistant tumor clones. We show that the addition of a newly identified CDK7/12 inhibitor, THZ1, to targeted therapy enhances cell killing and impedes the emergence of drug-resistant cell populations in diverse cellular and in vivo cancer models. We propose that targeted therapy induces a state of transcriptional dependency in a subpopulation of cells poised to become drug tolerant, which THZ1 can exploit by blocking dynamic transcriptional responses, promoting remodeling of enhancers and key signaling outputs required for tumor cell survival in the setting of targeted therapy. These findings suggest that the addition of THZ1 to targeted therapies is a promising broad-based strategy to hinder the emergence of drug-resistant cancer cell populations.Significance: CDK7/12 inhibition prevents active enhancer formation at genes, promoting resistance emergence in response to targeted therapy, and impedes the engagement of transcriptional programs required for tumor cell survival. CDK7/12 inhibition in combination with targeted cancer therapies may serve as a therapeutic paradigm for enhancing the effectiveness of targeted therapies. Cancer Discov; 8(1); 59-73. ©2017 AACR.See related commentary by Carugo and Draetta, p. 17This article is highlighted in the In This Issue feature, p. 1.

The impact of the MYB-NFIB fusion proto-oncogene in vivo

Recurrent fusion of the v-myb avian myelobastosis viral oncogene homolog (MYB) and nuclear factor I/B (NFIB) generates the MYB-NFIB transcription factor, which has been detected in a high percentage of individuals with adenoid cystic carcinoma (ACC). To understand the functional role of this fusion protein in carcinogenesis, we generated a conditional mutant transgenic mouse that expresses MYB-NFIB along with p53 mutation in tissues that give rise to ACC: mammary tissue, salivary glands, or systemically in the whole body. Expression of the oncogene in mammary tissue resulted in hyperplastic glands that developed into adenocarcinoma in 27.3% of animals. Systemic expression of the MYB-NFIB fusion caused more rapid development of this breast phenotype, but mice died due to abnormal proliferation in the glomerular compartment of the kidney, which led to development of glomerulonephritis. These findings suggest the MYB-NFIB fusion is oncogenic and treatments targeting this transcription factor may lead to therapeutic responses in ACC patients.

MEK inhibitor trametinib does not prevent the growth of anaplastic lymphoma kinase (ALK)-addicted neuroblastomas

Activation of the RAS-RAF-MEK-ERK signaling pathway is implicated in driving the initiation and progression of multiple cancers. Several inhibitors targeting the RAS-MAPK pathway are clinically approved as single- or polyagent therapies for patients with specific types of cancer. One example is the MEK inhibitor trametinib, which is included as a rational polytherapy strategy for treating EML4-ALK-positive, EGFR-activated, or KRAS-mutant lung cancers and neuroblastomas that also contain activating mutations in the RAS-MAPK pathway. In addition, in neuroblastoma, a heterogeneous disease, relapse cases display an increased rate of mutations in ALK, NRAS, and NF1, leading to increased activation of RAS-MAPK signaling. Co-targeting ALK and the RAS-MAPK pathway is an attractive option, because monotherapies have not yet produced effective results in ALK-addicted neuroblastoma patients. We evaluated the response of neuroblastoma cell lines to MEK-ERK pathway inhibition by trametinib. In contrast to RAS-MAPK pathway-mutated neuroblastoma cell lines, ALK-addicted neuroblastoma cells treated with trametinib showed increased activation (inferred by phosphorylation) of the kinases AKT and ERK5. This feedback response was mediated by the mammalian target of rapamycin complex 2-associated protein SIN1, resulting in increased survival and proliferation that depended on AKT signaling. In xenografts in mice, trametinib inhibited the growth of EML4-ALK-positive non-small cell lung cancer and RAS-mutant neuroblastoma but not ALK-addicted neuroblastoma. Thus, our results advise against the seemingly rational option of using MEK inhibitors to treat ALK-addicted neuroblastoma.

The role of the ALK receptor in cancer biology

A vast array of oncogenic variants has been identified for anaplastic lymphoma kinase (ALK). Therefore, there is a need to better understand the role of ALK in cancer biology in order to optimise treatment strategies. This review summarises the latest research on the receptor tyrosine kinase ALK, and how this information can guide the management of patients with cancer that is ALK-positive. A variety of ALK gene alterations have been described across a range of tumour types, including point mutations, deletions and rearrangements. A wide variety of ALK fusions, in which the kinase domain of ALK and the amino-terminal portion of various protein partners are fused, occur in cancer, with echinoderm microtubule-associated protein-like 4 (EML4)-ALK being the most prevalent in non-small-cell lung cancer (NSCLC). Different ALK fusion proteins can mediate different signalling outputs, depending on properties such as subcellular localisation and protein stability. The ALK fusions found in tumours lack spatial and temporal regulation, which can also affect dimerisation and substrate specificity. Two ALK tyrosine kinase inhibitors (TKIs), crizotinib and ceritinib, are currently approved in Europe for use in ALK-positive NSCLC and several others are in development. These ALK TKIs bind slightly differently within the ATP-binding pocket of the ALK kinase domain and are associated with the emergence of different resistance mutation patterns during therapy. This emphasises the need to tailor the sequence of ALK TKIs according to the ALK signature of each patient. Research into the oncogenic functions of ALK, and fast paced development of ALK inhibitors, has substantially improved outcomes for patients with ALK-positive NSCLC. Limited data are available surrounding the physiological ligand-stimulated activation of ALK signalling and further research is needed. Understanding the role of ALK in tumour biology is key to further optimising therapeutic strategies for ALK-positive disease.

Spotlight on ceritinib in the treatment of ALK+ NSCLC: design, development and place in therapy

The identification of echinoderm microtubule-associated protein-like 4 (EML4) and anaplastic lymphoma kinase (ALK) fusion gene in non-small cell lung cancer (NSCLC) has radically changed the treatment of a subset of patients harboring this oncogenic driver. Crizotinib was the first ALK tyrosine kinase inhibitor to receive fast approval and is currently indicated as the first-line therapy for advanced, ALK-positive NSCLC patients. However, despite crizotinib's efficacy, patients almost invariably progress, with the central nervous system being one of the most common sites of relapse. Different mechanisms of acquired resistance have been identified, including secondary ALK mutations, ALK copy number alterations and activation of bypass tracks. Different highly potent and brain-penetrant next-generation ALK inhibitors have been developed and tested in NSCLC patients with ALK rearrangements. Ceritinib, a structurally distinct and selective ALK inhibitor, showed 20 times higher potency than crizotinib in inhibiting ALK and had activity against the most common crizotinib-resistant mutations, including L1196M and G1269A, in preclinical models. In Phase I and II studies, ceritinib demonstrated pronounced activity in both crizotinib-naïve and crizotinib-refractory patients, with responses observed regardless of the presence of ALK resistance mutations. Ceritinib was the first ALK inhibitor to be approved for the treatment of crizotinib-refractory, ALK-rearranged NSCLC, and recent results from a Phase III study have demonstrated superior efficacy compared to standard chemotherapy in the first- and second-line setting. We provide an extensive overview of ceritinib from the design of the compound through preclinical data until efficacy and toxicity results from Phase I-III clinical studies. We review the molecular alterations associated with resistance to ceritinib and highlight the importance of obtaining tumor biopsy at progression to tailor therapy based upon the underlying resistance mechanism. We finally provide an outlook on novel rational therapeutic combinations.

Interleukin-17A Promotes Lung Tumor Progression through Neutrophil Attraction to Tumor Sites and Mediating Resistance to PD-1 Blockade

INTRODUCTION

Proinflammatory cytokine interleukin-17A (IL-17A) is overexpressed in a subset of patients with lung cancer. We hypothesized that IL-17A promotes a protumorigenic inflammatory phenotype and inhibits antitumor immune responses.

METHODS

We generated bitransgenic mice expressing a conditional IL-17A allele along with conditional Kras^G12D and performed immune phenotyping of mouse lungs, a survival analysis, and treatment studies with antibodies either blocking programmed cell death 1 (PD-1) or IL-6 or depleting neutrophils. To support the preclinical findings, we analyzed human gene expression data sets and immune profiled patient lung tumors.

RESULTS

Tumors in IL-17:Kras^G12D mice grew more rapidly, resulting in a significantly shorter survival as compared with that of Kras^G12D mice. IL-6, granulocyte colony-stimulating factor (G-CSF), milk fat globule-EGF factor 8 protein, and C-X-C motif chemokine ligand 1 were increased in the lungs of IL17:Kras mice. Time course analysis revealed that levels of tumor-associated neutrophils were significantly increased, and lymphocyte recruitment was significantly reduced in IL17:Kras^G12D mice as compared with in Kras^G12D mice. In therapeutic studies PD-1 blockade was not effective in treating IL-17:Kras^G12D tumors. In contrast, blocking IL-6 or depleting neutrophils with an anti-Ly-6G antibody in the IL17:Kras^G12D tumors resulted in a clinical response associated with T-cell activation. In tumors from patients with lung cancer with KRAS mutation we found a correlation between higher levels of IL-17A and colony- stimulating factor 3 and a significant correlation among high neutrophil and lower T-cell numbers.

CONCLUSIONS

Here we have shown that an increase in a single cytokine, IL-17A, without additional mutations can promote lung cancer growth by promoting inflammation, which contributes to resistance to PD-1 blockade and sensitizes tumors to cytokine and neutrophil depletion.

ALK: a tyrosine kinase target for cancer therapy

The anaplastic lymphoma kinase (ALK) gene plays an important physiologic role in the development of the brain and can be oncogenically altered in several malignancies, including non-small-cell lung cancer (NSCLC) and anaplastic large cell lymphomas (ALCL). Most prevalent ALK alterations are chromosomal rearrangements resulting in fusion genes, as seen in ALCL and NSCLC. In other tumors, ALK copy-number gains and activating ALK mutations have been described. Dramatic and often prolonged responses are seen in patients with ALK alterations when treated with ALK inhibitors. Three of these—crizotinib, ceritinib, and alectinib—are now FDA approved for the treatment of metastatic NSCLC positive for ALK fusions. However, the emergence of resistance is universal. Newer ALK inhibitors and other targeting strategies are being developed to counteract the newly emergent mechanism(s) of ALK inhibitor resistance. This review outlines the recent developments in our understanding and treatment of tumors with ALK alterations.

Identification, transcriptional and functional analysis of heat-shock protein 90s in banana (Musa acuminata L.) highlight their novel role in melatonin-mediated plant response to Fusarium wilt

As one popular fresh fruit, banana (Musa acuminata) is cultivated in the world's subtropical and tropical areas. In recent years, pathogen Fusarium oxysporum f. sp. cubense (Foc) has been widely and rapidly spread to banana cultivated areas, causing substantial yield loss. However, the molecular mechanism of banana response to Foc remains unclear, and functional identification of disease-related genes is also very limited. In this study, nine 90 kDa heat-shock proteins (HSP90s) were genomewide identified. Moreover, the expression profile of them in different organs, developmental stages, and in response to abiotic and fungal pathogen Foc were systematically analyzed. Notably, we found that the transcripts of 9 MaHSP90s were commonly regulated by melatonin (N-acetyl-5-methoxytryptamine) and Foc infection. Further studies showed that exogenous application of melatonin improved banana resistance to Fusarium wilt, but the effect was lost when cotreated with HSP90 inhibitor (geldanamycin, GDA). Moreover, melatonin and GDA had opposite effect on auxin level in response to Foc4, while melatonin and GDA cotreated plants had no significant effect, suggesting the involvement of MaHSP90s in the cross talk of melatonin and auxin in response to fungal infection. Taken together, this study demonstrated that MaHSP90s are essential for melatonin-mediated plant response to Fusarium wilt, which extends our understanding the putative roles of MaHSP90s as well as melatonin in the biological control of banana Fusarium wilt.

Co-clinical quantitative tumor volume imaging in ALK-rearranged NSCLC treated with crizotinib

PURPOSE

To evaluate and compare the volumetric tumor burden changes during crizotinib therapy in mice and human cohorts with ALK-rearranged non-small-cell lung cancer (NSCLC).

METHODS

Volumetric tumor burden was quantified on serial imaging studies in 8 bitransgenic mice with ALK-rearranged adenocarcinoma treated with crizotinib, and in 33 human subjects with ALK-rearranged NSCLC treated with crizotinib. The volumetric tumor burden changes and the time to maximal response were compared between mice and humans.

RESULTS

The median tumor volume decrease (%) at the maximal response was -40.4% (range: -79.5%-+11.7%) in mice, and -72.9% (range: -100%-+72%) in humans (Wilcoxon p=0.03). The median time from the initiation of therapy to maximal response was 6 weeks in mice, and 15.7 weeks in humans. Overall volumetric response rate was 50% in mice and 97% in humans. Spider plots of tumor volume changes during therapy demonstrated durable responses in the human cohort, with a median time on therapy of 13.1 months.

CONCLUSION

The present study described an initial attempt to evaluate quantitative tumor burden changes in co-clinical imaging studies of genomically-matched mice and human cohorts with ALK-rearranged NSCLC treated with crizotinib. Differences are noted in the degree of maximal volume response between the two cohorts in this well-established paradigm of targeted therapy, indicating a need for further studies to optimize co-clinical trial design and interpretation.

Coupling an EML4-ALK-centric interactome with RNA interference identifies sensitizers to ALK inhibitors

Patients with lung cancers harboring anaplastic lymphoma kinase (ALK) gene fusions benefit from treatment with ALK inhibitors, but acquired resistance inevitably arises. A better understanding of proximal ALK signaling mechanisms may identify sensitizers to ALK inhibitors that disrupt the balance between prosurvival and proapoptotic effector signals. Using affinity purification coupled with mass spectrometry in an ALK fusion lung cancer cell line (H3122), we generated an ALK signaling network and investigated signaling activity using tyrosine phosphoproteomics. We identified a network of 464 proteins composed of subnetworks with differential response to ALK inhibitors. A small hairpin RNA screen targeting 407 proteins in this network revealed 64 and 9 proteins that when knocked down sensitized cells to crizotinib and alectinib, respectively. Among these, knocking down fibroblast growth factor receptor substrate 2 (FRS2) or coiled-coil and C2 domain-containing protein 1A (CC2D1A), both scaffolding proteins, sensitized multiple ALK fusion cell lines to the ALK inhibitors crizotinib and alectinib. Collectively, our data set provides a resource that enhances our understanding of signaling and drug resistance networks consequent to ALK fusions and identifies potential targets to improve the efficacy of ALK inhibitors in patients.

Personalized treatment in advanced ALK-positive non-small cell lung cancer: from bench to clinical practice

The discovery of anaplastic lymphoma kinase (ALK) gene rearrangements and the development of tyrosine kinase inhibitors (TKI) that target them have achieved unprecedented success in the management of patients with ALK-positive non-small cell lung cancer (NSCLC). Despite the high efficacy of crizotinib, the first oral ALK TKI approved for the treatment of ALK-positive NSCLC, almost all patients inevitably develop acquired resistance, showing disease progression in the brain or in other parenchymal sites. Second- or third-generation ALK TKIs have shown to be active in crizotinib-pretreated or crizotinib-naïve ALK-positive patients, even in those with brain metastases. In this review, the current knowledge regarding ALK-positive NSCLC, focusing on the biology of the disease and the available therapeutic options are discussed.

Efficacy of crizotinib in first-line treatment of adults with ALK-positive advanced NSCLC

INTRODUCTION

The treatment of advanced non-small cell lung cancer (NSCLC) has evolved from palliative cytotoxic chemotherapy to precise medicine based on genetic alternations over the last decade. Anaplastic lymphoma kinase (ALK) rearrangement characterizes a molecular subset of NSCLC with an impressive response to crizotinib.

AREAS COVERED

To analyze the efficacy of crizotinib in first-line treatment of adults with advanced ALK-positive NSCLC, updated data on development and recent advances of first-line crizotinib in this subset population are reviewed.

EXPERT OPINION

To date, crizotinib should be established as a standard of care in previously untreated advanced NSCLC with ALK-rearrangement. However, the efficacy of first-line crizotinib is limited by acquired resistance. Second generation ALK inhibitors have demonstrated clinical activity in both crizotinib-refractory and crizotinib naïve setting. How to maximize first-line benefit for advanced ALK-positive NSCLC remains challenging. Combinational strategy, advances in companion diagnostics and optimization of ALK inhibitors might contribute to improve outcome in this subset of patients in future.

Total Body Metabolic Tumor Response in ALK Positive Non-Small Cell Lung Cancer Patients Treated with ALK Inhibition

BACKGROUND

In ALK-positive advanced NSCLC, crizotinib has a high response rate and effectively increases quality of life and survival. CT measurement of the tumor may insufficiently reflect the actual tumor load changes during targeted therapy with crizotinib. We explored whether 18F-FDG PET measured metabolic changes are different from CT based changes and studied the impact of these changes on disease progression.

METHODS

18F-FDG PET/CT was performed prior to and after 6 weeks of crizotinib treatment. Tumor response on CT was classified with RECIST 1.1, while 18F-FDG PET response was assessed according to the 1999 EORTC recommendations and PERCIST criteria. Agreement was assessed using McNemars test. During follow-up, patients received additional PET/CT during crizotinib treatment and second generation ALK inhibition. We assessed whether PET was able to detect progression earlier then CT.

RESULTS

In this exploratory study 15 patients were analyzed who were treated with crizotinib. There was a good agreement in the applicability of CT and 18F-FDG PET/CT using the EORTC recommendations. During first line crizotinib and subsequent second line ALK inhibitors, PET was able to detect progression earlier then CT in 10/22 (45%) events of progression and in the others disease progression was detected simultaneously.

CONCLUSION

In advanced ALK positive NSCLC PET was able to detect progressive disease earlier than with CT in nearly half of the assessments while both imaging tests performed similar in the others.

Overcoming resistance to first/second generation epidermal growth factor receptor tyrosine kinase inhibitors and ALK inhibitors in oncogene-addicted advanced non-small cell lung cancer

Epidermal growth factor receptor (EGFR) activating mutations and anaplastic lymphoma kinase (ALK) gene rearrangement in advanced non-small cell lung cancer (NSCLC) represent the two oncogenic events with an impact on current clinical practice. EGFR tyrosine kinase inhibitors (TKIs) and crizotinib are the standard of care for the treatment of EGFR mutant and ALK gene rearranged advanced NSCLC patients. Unfortunately, despite initial clinical benefit, acquired resistance to EGFR-TKIs or crizotinib usually develops after an average of 10-12 months of treatment. The aim of this review is to describe the mechanisms of resistance to first/second generation EGFR-TKIs and crizotinib. In particular, we focus on strategies to overcome resistance due to secondary EGFR T790M mutation and mutations of the ALK domain.

A new look at the ALK gene in cancer: copy number gain and amplification

To date, ALK-rearrangement is a molecular target in several cancers, i.e. NSCLC. The dramatic benefits of crizotinib have prompted research into identifying other possible patients carrying ALK gene alterations with possible clinical significance. The ALK gene is involved not only in several rearrangements but also in other alterations such as amplification. ALK-amplification (ALK-A) is a common genetic event in several cancers, generally associated with poor outcome and more aggressive behaviour. Here we review the role of ALK-A in cancer as a prognostic and predictive biomarker. Furthermore, several critical issues regarding ALK-A in relation to; methods of detection, acquired resistance and ALK second generation inhibitors are analyzed. We conclude that ALK-A could be an intriguing alteration in the context of targeted therapy.

Mouse models for ROS1-fusion-positive lung cancers and their application to the analysis of multikinase inhibitor efficiency

ROS1-fusion genes, resulting from chromosomal rearrangement, have been reported in 1-2% of human non-small cell lung cancer cases. More than 10 distinct ROS1-fusion genes, including break-point variants, have been identified to date. In this study, to investigate the in vivo oncogenic activities of one of the most frequently detected fusions, CD74-ROS1, as well as another SDC4-ROS1 fusion that has also been reported in several studies, we generated transgenic (TG) mouse strains that express either of the two ROS1-fusion genes specifically in lung alveolar type II cells. Mice in all TG lines developed tumorigenic nodules in the lung, and a few strains of both TG mouse lines demonstrated early-onset nodule development (multiple tumor lesions present in the lung at 2-4 weeks after birth); therefore, these two strains were selected for further investigation. Tumors developed progressively in the untreated TG mice of both lines, whereas those receiving oral administration of an ALK/MET/ROS1 inhibitor, crizotinib, and an ALK/ROS1 inhibitor, ASP3026, showed marked reduction in the tumor burden. Collectively, these data suggest that each of these two ROS1-fusion genes acts as a driver for the pathogenesis of lung adenocarcinoma in vivo The TG mice developed in this study are expected to serve as valuable tools for exploring novel therapeutic agents against ROS1-fusion-positive lung cancer.