A novel ALK secondary mutation and EGFR signaling cause resistance to ALK kinase inhibitors

ALK inhibitors in cancer: mechanisms of resistance and therapeutic management strategies

Anaplastic lymphoma kinase (ALK) gene rearrangements have been identified as potent oncogenic drivers in several malignancies, including non-small cell lung cancer (NSCLC). The discovery of ALK inhibition using a tyrosine kinase inhibitor (TKI) has dramatically improved the outcomes of patients with ALK-mutated NSCLC. However, the emergence of intrinsic and acquired resistance inevitably occurs with ALK TKI use. This review describes the molecular mechanisms of ALK TKI resistance and discusses management strategies to overcome therapeutic resistance.

Current treatment and novel insights regarding ROS1-targeted therapy in malignant tumors

BACKGROUND

The proto-oncogene ROS1 encodes an intrinsic type I membrane protein of the tyrosine kinase/insulin receptor family. ROS1 facilitates the progression of various malignancies via self-mutations or rearrangements. Studies on ROS1-directed tyrosine kinase inhibitors have been conducted, and some have been approved by the FDA for clinical use. However, the adverse effects and mechanisms of resistance associated with ROS1 inhibitors remain unknown. In addition, next-generation ROS1 inhibitors, which have the advantage of treating central nervous system metastases and alleviating endogenous drug resistance, are still in the clinical trial stage.

METHOD

In this study, we searched relevant articles reporting the mechanism and clinical application of ROS1 in recent years; systematically reviewed the biological mechanisms, diagnostic methods, and research progress on ROS1 inhibitors; and provided perspectives for the future of ROS1-targeted therapy.

RESULTS

ROS1 is most expressed in malignant tumours. Only a few ROS1 kinase inhibitors are currently approved for use in NSCLC, the efficacy of other TKIs for NSCLC and other malignancies has not been ascertained. There is no effective standard treatment for adverse events or resistance to ROS1-targeted therapy. Next-generation TKIs appear capable of overcoming resistance and delaying central nervous system metastasis, but with a greater incidence of adverse effects.

CONCLUSIONS

Further research on next-generation TKIs regarding the localization of ROS1 and its fusion partners, binding sites for targeted drugs, and coadministration with other drugs is required. The correlation between TKIs and chemotherapy or immunotherapy in clinical practice requires further study.

Molecular mechanisms underlying the regulation of tumour suppressor genes in lung cancer

Tumour suppressor genes play a cardinal role in the development of a large array of human cancers, including lung cancer, which is one of the most frequently diagnosed cancers worldwide. Therefore, extensive studies have been committed to deciphering the underlying mechanisms of alterations of tumour suppressor genes in governing tumourigenesis, as well as resistance to cancer therapies. In spite of the encouraging clinical outcomes demonstrated by lung cancer patients on initial treatment, the subsequent unresponsiveness to first-line treatments manifested by virtually all the patients is inherently a contentious issue. In light of the aforementioned concerns, this review compiles the current knowledge on the molecular mechanisms of some of the tumour suppressor genes implicated in lung cancer that are either frequently mutated and/or are located on the chromosomal arms having high LOH rates (1p, 3p, 9p, 10q, 13q, and 17p). Our study identifies specific genomic loci prone to LOH, revealing a recurrent pattern in lung cancer cases. These loci, including 3p14.2 (FHIT), 9p21.3 (p16INK4a), 10q23 (PTEN), 17p13 (TP53), exhibit a higher susceptibility to LOH due to environmental factors such as exposure to DNA-damaging agents (carcinogens in cigarette smoke) and genetic factors such as chromosomal instability, genetic mutations, DNA replication errors, and genetic predisposition. Furthermore, this review summarizes the current treatment landscape and advancements for lung cancers, including the challenges and endeavours to overcome it. This review envisages inspired researchers to embark on a journey of discovery to add to the list of what was known in hopes of prompting the development of effective therapeutic strategies for lung cancer.

MIG6 Mediates Adaptive and Acquired Resistance to ALK/ROS1 Fusion Kinase Inhibition through EGFR Bypass Signaling

Despite the initial benefit from tyrosine kinase inhibitors (TKI) targeting oncogenic ALK and ROS1 gene fusions in non-small cell lung cancer, complete responses are rare and resistance ultimately emerges from residual tumor cells. Although several acquired resistance mechanisms have been reported at the time of disease progression, adaptative resistance mechanisms that contribute to residual diseases before the outgrowth of tumor cells with acquired resistance are less clear. For the patients who have progressed after TKI treatments, but do not demonstrate ALK/ROS1 kinase mutations, there is a lack of biomarkers to guide effective treatments. Herein, we found that phosphorylation of MIG6, encoded by the ERRFI1 gene, was downregulated by ALK/ROS1 inhibitors as were mRNA levels, thus potentiating EGFR activity to support cell survival as an adaptive resistance mechanism. MIG6 downregulation was sustained following chronic exposure to ALK/ROS1 inhibitors to support the establishment of acquired resistance. A higher ratio of EGFR to MIG6 expression was found in ALK TKI-treated and ALK TKI-resistant tumors and correlated with the poor responsiveness to ALK/ROS1 inhibition in patient-derived cell lines. Furthermore, we identified and validated a MIG6 EGFR-binding domain truncation mutation in mediating resistance to ROS1 inhibitors but sensitivity to EGFR inhibitors. A MIG6 deletion was also found in a patient after progressing to ROS1 inhibition. Collectively, this study identifies MIG6 as a novel regulator for EGFR-mediated adaptive and acquired resistance to ALK/ROS1 inhibitors and suggests EGFR to MIG6 ratios and MIG6-damaging alterations as biomarkers to predict responsiveness to ALK/ROS1 and EGFR inhibitors.

Recent advances in molecular targeted therapy of lung cancer: Possible application in translation medicine

Lung cancer is one of the leading causes of death among all cancer deaths. This cancer is classified into two different histological subtypes: non-small cell lung cancer (NSCLC), which is the most common subtype, and small cell lung cancer (SCLC), which is the most aggressive subtype. Understanding the molecular characteristics of lung cancer has expanded our knowledge of the cellular origins and molecular pathways affected by each of these subtypes and has contributed to the development of new therapies. Traditional treatments for lung cancer include surgery, chemotherapy, and radiotherapy. Advances in understanding the nature and specificity of lung cancer have led to the development of immunotherapy, which is the newest and most specialized treatment in the treatment of lung cancer. Each of these treatments has advantages and disadvantages and causes side effects. Today, combination therapy for lung cancer reduces side effects and increases the speed of recovery. Despite the significant progress that has been made in the treatment of lung cancer in the last decade, further research into new drugs and combination therapies is needed to extend the clinical benefits and improve outcomes in lung cancer. In this review article, we discussed common lung cancer treatments and their combinations from the most advanced to the newest.

An advanced NSCLC patient with ALK-RNF144A and HIP1-ALK fusions treated with ALK-TKI combination therapy: a case report

Background

Anaplastic lymphoma kinase (ALK) rearrangement is one of the most important drivers in non-small cell lung cancer (NSCLC). Despite the effectiveness to canonical 3'-ALK fusions, the clinical efficacy of ALK inhibitors in patients with complex ALK fusions, such as nonreciprocal/reciprocal translocation remains uncertain. Exploring the optimal therapeutic regimens for this subset of patients is of crucial clinical significance.

Case Description

We reported a female patient diagnosed with stage IVB lung adenocarcinoma (LUAD) harboring a novel ALK-RNF144A fusion, concurrent with a Huntingtin-interacting protein 1 (HIP1)-ALK fusion and a RB1 loss-of-function variant. The patient sequentially received multiple lines of treatment with ALK-tyrosine kinase inhibitor (TKI), chemotherapy, radiotherapy and ALK-TKI combined with anti-angiogenesis. Disease progression accompanied by a squamous cell carcinoma transformation was indicated after ALK-TKI combined with anti-angiogenesis and both ALK-RNF144A and HIP1-ALK fusions were retained in the tumor. The patient was subsequently treated with a third generation ALK-TKI, lorlatinib, in combination with albumin-bound paclitaxel and anlotinib, and then achieved stable disease. The patient remained on the treatment as of the last follow-up resulting in an overall survival (OS) of more than 18 months.

Conclusions

We have reported an advanced NSCLC patient with a complex nonreciprocal/reciprocal ALK translocation containing a novel ALK-RNF144A fusion, concurrent with a RB1 loss-of-function mutation, who subsequently experienced pathological squamous cell carcinoma transformation. The combined treatment with ALK-TKI, chemotherapy, and anti-angiogenesis demonstrates clinical efficacy and may provide optional therapeutic strategies for this phenotype.

From Development to Place in Therapy of Lorlatinib for the Treatment of ALK and ROS1 Rearranged Non-Small Cell Lung Cancer (NSCLC)

Following the results of the CROWN phase III trial, the third-generation macrocyclic ALK inhibitor lorlatinib has been introduced as a salvage option after the failure of a first-line TKI in ALK-rearranged NSCLC, while its precise role in the therapeutic algorithm of ROS1 positive disease is still to be completely defined. The ability to overcome acquired resistance to prior generation TKIs (alectinib, brigatinib, ceritinib, and crizotinib) and the high intracranial activity in brain metastatic disease thanks to increased blood-brain barrier penetration are the reasons for the growing popularity and interest in this molecule. Nevertheless, the major vulnerability of this drug resides in a peculiar profile of related collateral events, with neurological impairment being the most conflicting and debated clinical issue. The cognitive safety concern, the susceptibility to heterogeneous resistance pathways, and the absence of a valid alternative in the second line are strongly jeopardizing a potential paradigm shift in this oncogene-addicted disease. So, when prescribing lorlatinib, clinicians must face two diametrically opposed characteristics: a great therapeutic potential without the intrinsic limitations of its precursor TKIs, a cytotoxic activity threatened by suboptimal tolerability, and the unavoidable onset of resistance mechanisms we cannot properly manage yet. In this paper, we give a critical point of view on the stepwise introduction of this promising drug into clinical practice, starting from its innovative molecular and biochemical properties to intriguing future developments, without forgetting its weaknesses.

MIG6 loss confers resistance to ALK/ROS1 inhibitors in NSCLC through EGFR activation by low-dose EGF

Although tyrosine kinase inhibitor (TKI) therapy shows marked clinical efficacy in patients with anaplastic lymphoma kinase-positive (ALK+) and ROS proto-oncogene 1-positive (ROS1+) non-small cell lung cancer (NSCLC), most of these patients eventually relapse with acquired resistance. Therefore, genome-wide CRISPR/Cas9 knockout screening was performed using an ALK+ NSCLC cell line established from pleural effusion without ALK-TKI treatment. After 9 days of ALK-TKI therapy, sequencing analysis was performed, which identified several tumor suppressor genes, such as NF2 or MED12, and multiple candidate genes. Among them, this study focused on ERRFI1, which is known as MIG6 and negatively regulates EGFR signaling. Interestingly, MIG6 loss induced resistance to ALK-TKIs by treatment with quite a low dose of EGF, which is equivalent to plasma concentration, through the upregulation of MAPK and PI3K/AKT/mTOR pathways. Combination therapy with ALK-TKIs and anti-EGFR antibodies could overcome the acquired resistance in both in vivo and in vitro models. In addition, this verified that MIG6 loss induces resistance to ROS1-TKIs in ROS1+ cell lines. This study found a potentially novel factor that plays a role in ALK and ROS1-TKI resistance by activating the EGFR pathway with low-dose ligands.

Clinical Challenge of Two Competing Targetable Mutations in Non-Small-Cell Lung Cancer: A Case Report

The development of therapeutic agents targeting products of epidermal growth factor receptor (EGFR) gene mutation and anaplastic lymphoma kinase (ALK) rearrangements has improved survival in patients with non-small-cell lung cancer. EGFR and ALK mutations are generally regarded as mutually exclusive, and the presence of one in lieu of another influences the response to targeted therapy. We herein present an interesting case following the course of progression of a patient with synchronous lung cancers with a discordant mutation profile. The importance of this modality in the follow-up of lung cancer patients is illustrated, and the therapeutic implications of coexisting oncogenic drivers are briefly discussed.

Case report: Concomitant EGFR mutation and ALK rearrangement in non-small cell lung cancer

In non-small cell lung cancer (NSCLC), two key genetic alterations, epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements, are commonly believed to be mutually exclusive. Studies have reported that concurrent EGFR/ALK co-mutation in non-small cell lung cancer patients is rare, with a prevalence ranging from 0.1% to 1.6%. However, the clinical and pathological characteristics of these patients are not well-defined, and the optimal treatment approach for such cases remains controversial. In this report, we present a case of stage IV lung adenocarcinoma with both epidermal growth factor receptor and anaplastic lymphoma kinase mutations, along with high PD-L1 expression. The patient initially received treatment with epidermal growth factor receptor tyrosine kinase inhibitors (TKIs), but the disease progressed. However, following a switch to ALK-TKI therapy and local radiotherapy, the lesion showed regression. Our report also provides a comprehensive summary of the clinical and pathological features, as well as treatment strategies, for non-small cell lung cancer patients with concurrent epidermal growth factor receptor mutation and anaplastic lymphoma kinase rearrangement.

Treatment of advanced ALK-rearranged NSCLC following second-generation ALK-TKI failure

INTRODUCTION

Anaplastic lymphoma kinase (ALK) gene rearrangement is detected in approximately 3-5% of non-small cell lung cancer (NSCLC) cases. Tyrosine kinase inhibitors (TKIs) targeting ALK rearrangement (ALK-TKIs) have shown significant efficacy and improved the survival of patients with NSCLC exhibiting ALK rearrangement. However, almost all patients exhibit disease progression during TKI therapy owing to resistance acquired through various molecular mechanisms, including both ALK-dependent and ALK-independent.

AREAS COVERED

Here, we review the mechanisms underlying resistance to second-generation ALK-TKIs, and the clinical management strategies following resistance in patients with ALK rearrangement-positive NSCLC.

EXPERT OPINION

Treatment strategies following the failure of second-generation ALK-TKIs failure should be based on resistant mechanisms. For patients with ALK mutations who exhibit resistance to second-generation ALK-TKIs, lorlatinib is the primary treatment option. However, the identification of resistance profiles of second-generation ALK-TKIs can aid in the selection of an appropriate treatment strategy. In cases of ALK-dependent resistance mutations, lorlatinib could be the first choice as it exhibits the broadest coverage of mutations that lead to resistance against second-generation ALK-TKIs, such as G1202R, and L1196M. In cases of no resistance mutations, atezolizumab, bevacizumab, and platinum-based chemotherapy could be the alternative treatment options.

Therapeutic strategies to overcome EGFR mutations as acquired resistance mechanism in ALK-rearranged non-small-cell lung cancer: Case Reports

Introduction

ALK tyrosine kinase inhibitors (ALK TKIs) have improved prognosis in ALK-rearranged (ALK ⁺) non-small-cell lung cancer (NSCLC). However, drug resistance mechanisms occur inevitably during the course of treatment leading to disease progression. Activation of epidermal growth factor receptor (EGFR) bypass signaling pathway is an uncommon cause of acquired resistance to ALK TKIs.

Method

We present two patients with EML4-ALK rearranged NSCLC, developing an acquired EGFR resistance mutation after receiving multiple lines of ALK TKIs.

Results

While preclinical models have showed encouraging data, there is a critical need for clinical studies on treatment strategies to overcome this drug resistance. Three real-life therapeutic approaches were used in this report: i) using brigatinib, an inhibitor targeting both ALK and EGFR tyrosine kinases; ii) combining two ALK TKIs together; and iii) delivering doublet platinum chemotherapy. In case 1, time to treatment failure (TTF) was 9.5 months with brigatinib; in case 2, TTF was 10 months with combined TKIs (osimertinib and brigatinib), whereas TTF with chemotherapy was only 2 months. Tolerability profile TKIs combotherapy was acceptable.

Conclusion

These case reports underline the therapeutic complexity of EGFR-acquired resistance mutation in ALK⁺ NSCLC and offers some leads to solve this real-life clinical challenge.

Mechanisms of synergistic suppression of ALK-positive lung cancer cell growth by the combination of ALK and SHP2 inhibitors

Lung cancer is a major cause of cancer-related deaths. Alectinib is the first line of treatment for patients with ALK-positive lung cancer, but the survival rate beyond 2-3 years is low. Co-targeting secondary oncogenic drivers such as SHP2 is a potential strategy for improving drug efficacy. This is because SHP2 is expressed ubiquitously, but ALK expression is largely restricted to cancer cells. Thus, the combination of ALK and SHP2 inhibitors may provide a way to restrict synergistic cytotoxicity to cancer cells only, by reducing the dose of SHP2 inhibitors required for anticancer action and minimising SHP2-dependent systemic toxicity. The objective of this study was to investigate whether the combination of a SHP2 inhibitor (SHP099) with alectinib would synergistically suppress the growth of ALK-positive lung cancer cells. Our results demonstrated that the drug combination significantly and synergistically decreased cell viability at relatively low concentrations in ALK-positive H3122 and H2228 cells, due to G1 cell cycle arrest and increased apoptosis because of suppressed downstream RAS/MAPK signalling. The drug combination also induced the expression of mediators of the intrinsic apoptotic pathway, Bim and cleaved caspase-3, and modulated the expression of cell cycle mediators cyclin D1, cyclin B1, and phosphorylated CDK1.

Deciphering the Shared and Specific Drug Resistance Mechanisms of Anaplastic Lymphoma Kinase via Binding Free Energy Computation

Anaplastic lymphoma kinase (ALK), a tyrosine receptor kinase, has been proven to be associated with the occurrence of numerous malignancies. Although there have been already at least 3 generations of ALK inhibitors approved by FDA or in clinical trials, the occurrence of various mutations seriously attenuates the effectiveness of the drugs. Unfortunately, most of the drug resistance mechanisms still remain obscure. Therefore, it is necessary to reveal the bottom reasons of the drug resistance mechanisms caused by the mutations. In this work, on the basis of verifying the accuracy of 2 main kinds of binding free energy calculation methodologies [end-point method of Molecular Mechanics with Poisson-Boltzmann/Generalized Born and Surface Area (MM/PB(GB)SA) and alchemical method of Thermodynamic Integration (TI)], we performed a systematic analysis on the ALK systems to explore the underlying shared and specific drug resistance mechanisms, covering the one-drug-multiple-mutation and multiple-drug-one-mutation cases. Through conventional molecular dynamics (cMD) simulation in conjunction with MM/PB(GB)SA and umbrella sampling (US) in conjunction with contact network analysis (CNA), the resistance mechanisms of the in-pocket, out-pocket, and multiple-site mutations were revealed. Especially for the out-pocket mutation, a possible transfer chain of the mutation effect was revealed, and the reason why different drugs exhibited various sensitivities to the same mutation was also uncovered. The proposed mechanisms may be prevalent in various drug resistance cases.

Small Molecule Inhibitors as Therapeutic Agents Targeting Oncogenic Fusion Proteins: Current Status and Clinical

Oncogenic fusion proteins, arising from chromosomal rearrangements, have emerged as prominent drivers of tumorigenesis and crucial therapeutic targets in cancer research. In recent years, the potential of small molecular inhibitors in selectively targeting fusion proteins has exhibited significant prospects, offering a novel approach to combat malignancies harboring these aberrant molecular entities. This review provides a comprehensive overview of the current state of small molecular inhibitors as therapeutic agents for oncogenic fusion proteins. We discuss the rationale for targeting fusion proteins, elucidate the mechanism of action of inhibitors, assess the challenges associated with their utilization, and provide a summary of the clinical progress achieved thus far. The objective is to provide the medicinal community with current and pertinent information and to expedite the drug discovery programs in this area.

EML4-ALK biology and drug resistance in non-small cell lung cancer: a new phase of discoveries

Anaplastic lymphoma kinase (ALK) can be driven to oncogenic activity by different types of mutational events such as point-mutations, for example F1174L in neuroblastoma, and gene fusions, for example with echinoderm microtubule-associated protein-like 4 (EML4) in non-small cell lung cancer (NSCLC). EML4-ALK variants result from different breakpoints, generating fusions of different sizes and properties. The most common variants (Variant 1 and Variant 3) form cellular compartments with distinct physical properties. The presence of a partial, probably misfolded beta-propeller domain in variant 1 confers solid-like properties to the compartments it forms, greater dependence on Hsp90 for protein stability and higher cell sensitivity to ALK tyrosine kinase inhibitors (TKIs). These differences translate to the clinic because variant 3, on average, worsens patient prognosis and increases metastatic risk. Latest generation ALK-TKIs are beneficial for most patients with EML4-ALK fusions. However, resistance to ALK inhibitors can occur via point-mutations within the kinase domain of the EML4-ALK fusion, for example G1202R, reducing inhibitor effectiveness. Here, we discuss the biology of EML4-ALK variants, their impact on treatment response, ALK-TKI drug resistance mechanisms and potential combination therapies.

Understanding and targeting resistance mechanisms in cancer

Resistance to cancer therapies has been a commonly observed phenomenon in clinical practice, which is one of the major causes of treatment failure and poor patient survival. The reduced responsiveness of cancer cells is a multifaceted phenomenon that can arise from genetic, epigenetic, and microenvironmental factors. Various mechanisms have been discovered and extensively studied, including drug inactivation, reduced intracellular drug accumulation by reduced uptake or increased efflux, drug target alteration, activation of compensatory pathways for cell survival, regulation of DNA repair and cell death, tumor plasticity, and the regulation from tumor microenvironments (TMEs). To overcome cancer resistance, a variety of strategies have been proposed, which are designed to enhance the effectiveness of cancer treatment or reduce drug resistance. These include identifying biomarkers that can predict drug response and resistance, identifying new targets, developing new targeted drugs, combination therapies targeting multiple signaling pathways, and modulating the TME. The present article focuses on the different mechanisms of drug resistance in cancer and the corresponding tackling approaches with recent updates. Perspectives on polytherapy targeting multiple resistance mechanisms, novel nanoparticle delivery systems, and advanced drug design tools for overcoming resistance are also reviewed.

Sustained Improvement in the Management of Patients with Non-Small-Cell Lung Cancer (NSCLC) Harboring ALK Translocation: Where Are We Running?

ALK translocation amounts to around 3-7% of all NSCLCs. The clinical features of ALK+ NSCLC are an adenocarcinoma histology, younger age, limited smoking history, and brain metastases. The activity of chemotherapy and immunotherapy is modest in ALK+ disease. Several randomized trials have proven that ALK inhibitors (ALK-Is) have greater efficacy with respect to platinum-based chemotherapy and that second/third generation ALK-Is are better than crizotinib in terms of improvements in median progression-free survival and brain metastases management. Unfortunately, most patients develop acquired resistance to ALK-Is that is mediated by on- and off-target mechanisms. Translational and clinical research are continuing to develop new drugs and/or combinations in order to raise the bar and further improve the results attained up to now. This review summarizes first-line randomized clinical trials of several ALK-Is and the management of brain metastases with a focus on ALK-I resistance mechanisms. The last section addresses future developments and challenges.

New perspectives for targeting therapy in ALK-positive human cancers

Anaplastic lymphoma kinase (ALK) is a member of the insulin receptor protein-tyrosine kinase superfamily and was first discovered in anaplastic large-cell lymphoma (ALCL). ALK alterations, including fusions, over-expression and mutations, are highly associated with cancer initiation and progression. This kinase plays an important role in different cancers, from very rare to the more prevalent non-small cell lung cancers. Several ALK inhibitors have been developed and received Food and Drug Administration (FDA) approval. However, like other drugs used in targeted therapies, ALK inhibitors inevitably encounter cancer cell resistance. Therefore, monoclonal antibody screening based on extracellular domain or combination therapies may provide viable alternatives for treating ALK-positive tumors. In this review, we discuss the current understanding of wild-type ALK and fusion protein structures, the pathological functions of ALK, ALK target therapy, drug resistance and future therapeutic directions.

Iruplinalkib (WX‑0593), a novel ALK/ROS1 inhibitor, overcomes crizotinib resistance in preclinical models for non-small cell lung cancer

Despite remarkable initial responses of anaplastic lymphoma kinase (ALK) inhibitors in ALK-positive non-small cell lung cancer (NSCLC) patients, cancers eventually develop resistance within one to two years. This study aimed to compare the properties of iruplinalkib (WX‑0593) with other ALK inhibitors and report the comprehensive characterization of iruplinalkib against the crizotinib resistance. The inhibitory effect of iruplinalkib on kinase activity was detected. A kinase screen was performed to evaluate the selectivity of iruplinalkib. The effect of iruplinalkib on related signal transduction pathways of ALK and c-ros oncogene 1 (ROS1) kinases was examined. The cellular and in vivo activities of ALK inhibitors were compared in engineered cancer-derived cell lines and in mice xenograft models, respectively. Human hepatocytes derived from three donors were used for evaluating hepatic enzyme inducing activity. HEK293 cell lines expressing transportors were used to invesigated the drug interaction potential mediated by several transporters. The results showed iruplinalkib potently inhibited the tyrosine autophosphorylation of wild-type ALK, ALK^L1196M, ALK^C1156Y and epidermal growth factor receptor (EGFR)^L858R/T790M. The inhibitory effects of iruplinalkib in patient-derived xenograft and cell line-derived xenograft models were observed. Moreover, iruplinalkib showed robust antitumor effects in BALB/c nude mice xenograft models with ALK-/ROS1-positive tumors implanted subcutaneously, and the tumor suppressive effects in crizotinib-resistant model was significantly better than that of brigatinib. Iruplinalkib did not induce CYP1A2, CYP2B6 and CYP3A4 at therapeutic concentration, and was also a strong inhibitor of MATE1 and MATE2K transporters, as well as P-gp and BCRP. In conclusion, iruplinalkib, a highly active and selective ALK/ROS1 inhibitor, exhibited strong antitumor effects in vitro and in crizotinib-resistant models.

Molecular Anatomy of the EML4-ALK Fusion Protein for the Development of Novel Anticancer Drugs

The EML4 (echinoderm microtubule-associated protein-like 4)-ALK (anaplastic lymphoma kinase) fusion gene in non-small-cell lung cancer (NSCLC) was first identified in 2007. As the EML4-ALK fusion protein promotes carcinogenesis in lung cells, much attention has been paid to it, leading to the development of therapies for patients with NSCLC. These therapies include ALK tyrosine kinase inhibitors and heat shock protein 90 inhibitors. However, detailed information on the entire structure and function of the EML4-ALK protein remains deficient, and there are many obstacles to overcome in the development of novel anticancer agents. In this review, we describe the respective partial structures of EML4 and ALK that are known to date. In addition to their structures, noteworthy structural features and launched inhibitors of the EML4-ALK protein are summarized. Furthermore, based on the structural features and inhibitor-binding modes, we discuss strategies for the development of novel inhibitors targeting the EML4-ALK protein.

ALK-positive lung cancer: a moving target

Anaplastic lymphoma kinase (ALK) is a potent oncogenic driver in lung cancer. ALK tyrosine kinase inhibitors yield significant benefit in patients with ALK fusion-positive (ALK+) lung cancers; yet the durability of response is limited by drug resistance. Elucidation of on-target resistance mechanisms has facilitated the development of next-generation ALK inhibitors, but overcoming ALK-independent resistance mechanisms remains a challenge. In this Review, we discuss the molecular underpinnings of acquired resistance to ALK-directed therapy and highlight new treatment approaches aimed at inducing long-term remission in ALK+ disease.

Therapeutic strategies of dual-target small molecules to overcome drug resistance in cancer therapy

Despite some advances in targeted therapeutics of human cancers, curative cancer treatment still remains a tremendous challenge due to the occurrence of drug resistance. A variety of underlying resistance mechanisms to targeted cancer drugs have recently revealed that the dual-target therapeutic strategy would be an attractive avenue. Compared to drug combination strategies, one agent simultaneously modulating two druggable targets generally shows fewer adverse reactions and lower toxicity. As a consequence, the dual-target small molecule has been extensively explored to overcome drug resistance in cancer therapy. Thus, in this review, we focus on summarizing drug resistance mechanisms of cancer cells, such as enhanced drug efflux, deregulated cell death, DNA damage repair, and epigenetic alterations. Based upon the resistance mechanisms, we further discuss the current therapeutic strategies of dual-target small molecules to overcome drug resistance, which will shed new light on exploiting more intricate mechanisms and relevant dual-target drugs for future cancer therapeutics.

Clinicopathological and computed tomography features of patients with early-stage non-small-cell lung cancer harboring ALK rearrangement

BACKGROUND

Although some studies have assessed the correlation between computed tomography (CT) features and anaplastic lymphoma kinase (ALK) rearrangement in patients with non-small-cell lung cancer (NSCLC), few have focused on early-stage patients. The results of some previous studies are inconsistent and contradictory. Therefore, this study aimed to analyze the clinicopathological and CT features of patients with early-stage NSCLC harboring ALK rearrangement.

METHODS

This retrospective analysis included 65 patients with ALK rearrangement and 629 ALK-negative patients. All patients had surgically resected NSCLC and were diagnosed with stage IA or stage IIB NSCLC. Clinicopathological features and CT signs, including tumor size and density, consolidation tumor ratio (CTR), lesion location, round or irregular shape, lobulated or spiculated margins, air bronchograms, bubble-like lucency or cavities, and pleural retraction, were investigated according to different genotypes.

RESULTS

The prevalence of ALK rearrangement in patients with early-stage NSCLC was 9.3% (65/694). Patients with ALK rearrangement were significantly younger than those without ALK rearrangement (P = 0.033). The frequency of moderate cell differentiation was significantly lower in tumors with ALK rearrangement than in those without ALK rearrangement (46.2% vs. 59.8%, P = 0.034). The frequency of the mucinous subtype was significantly higher in the ALK-positive group than in the ALK-negative group (13.8% vs. 5.4%, P = 0.007). No significant differences were found in any CT signs between the ALK-positive and ALK-negative groups.

CONCLUSIONS

Patients with ALK-positive lung cancer may have specific clinicopathological features, including younger age, lower frequency of moderate cell differentiation, and higher frequency of the mucinous type. CT features may not correlate with ALK rearrangement in early-stage lung cancer. Immunohistochemistry or next-generation sequencing is needed to further clarify the genomic mutation status.

Autocrine EGF and TGF-α promote primary and acquired resistance to ALK/c-Met kinase inhibitors in non-small-cell lung cancer

Drug resistance severely limits the clinical therapeutic value of molecularly targeted drugs. Growth factors gain a tremendous amount of focus due to the ability to promote drug resistance in non-small-cell lung cancer (NSCLC). However, whether tumor cells themselves can mediate drug resistance by secreting growth factors needs further clarification. Here, we first screened growth factors to identify autocrine epidermal growth factor (EGF) and transforming growth factor alpha (TGF-α) that caused primary resistance to the ALK inhibitor TAE684 in H3122 cells and the c-MET-specific inhibitor SGX-523 in EBC-1 cells. Next, we discovered increased autocrine production of EGF and TGF-α in established acquired resistant H3122/TR and EBC-1/SR cells. Importantly, overexpression of EGF and TGF-α in two NSCLC cell lines produced resistance to TAE684 and SGX-523. Clinically, NSCLC patients with high expression of EGF and TGF-α developed primary resistance to crizotinib. Mechanistically, autocrine EGF and TGF-α activated EGFR signaling pathways to survive targeted c-Met and ALK inhibition. Furthermore, combined treatment with gefitinib circumvented EGF- and TGF-α-mediated primary and acquired resistance to TAE684/SGX-523. Taken together, these results suggested increased autocrine EGF and TGF-α conferred primary and acquired resistance to ALK/c-Met kinase inhibitors in NSCLC.

First-line crizotinib therapy is effective for a novel SEC31A-anaplastic lymphoma kinase fusion in a patient with stage IV lung adenocarcinoma: a case report and literature reviews

Anaplastic lymphoma kinase (ALK) fusion was found in 3-7% of all patients with nonsmall cell lung cancer. The efficacy of ALK-tyrosine kinase inhibitor (ALK-TKI) in EML4-ALK has been extensively studied, whereas little evidence is available on its efficacy in rare ALK fusions. Here, we report the performance of crizotinib in a 50-year-old male lung adenocarcinoma patient with a novel rare SEC31A-ALK fusion. Computed tomography (CT) scan revealed multiple patchy high-density shadows in both lungs. The larger ones are located near the spine in the right lung lower lobe (55 × 34 mm) and the left hilar region (45 × 26 mm), with multiple enlarged mediastinal and axillary lymph nodes. Biopsy by bronchoscopy revealed invasive adenocarcinoma. The pathological stage of T4N3M1b (clinical stage: IVA) was confirmed. Next-generation sequencing revealed SEC31A: exon20~ALK: exon20 fusion, ABCB1 amplification, FGF19 amplification, DAXX p.S213L, MUTYH p.R19*(germline mutation and pathogenic) with tumor mutational burden at 3.2 mutations/Mb, microsatellite stable, proficient mismatch repair and PD-L1 positive [immunohistochemistry, tumor proportion score(TPS) 1-49% (TPS = 25%)]. Based on these findings, crizotinib was recommended for the first-line treatment at 250 mg twice daily. The first CT assessment after 2-month therapy showed partial response (PR) for the two larger lesions, multiple shadows and nodules in both lungs and the mediastinal and axillary lymph nodes. Crizotinib at 250 mg twice a day was applied in the following 9 months. Assessment at every 3 months (up to 1-year after diagnosis) showed further absorption for all lesions (continuous PR). We reported a novel rare ALK fusion SEC31A: EXON20~ALK: exon20 and showed the effectiveness of crizotinib against the fusion. This study provided strong evidence for the efficacy of ALK-TKI for rare ALK fusion.

Comparative Efficacy of ALK Inhibitors for Treatment-Naïve ALK-Positive Advanced Non-Small Cell Lung Cancer with Central Nervous System Metastasis: A Network Meta-Analysis

Central nervous system (CNS) metastases and acquired resistance complicate the treatment of anaplastic lymphoma kinase (ALK) rearrangement-positive (ALK-p) advanced non-small cell lung cancer (NSCLC). Thus, this review aimed to provide a comprehensive overview of brain metastasis, acquired resistance, and prospects for overcoming these challenges. A network meta-analysis of relevant phase III randomized controlled trials was performed to compare the efficacies of multiple ALK inhibitors by drug and generation in overall patients with ALK-p untreated advanced NSCLC and a subgroup of patients with CNS metastases. The primary endpoint was progression-free survival (PFS). Generation-specific comparison results showed that third-generation ALK inhibitors were significantly more effective than second-generation ALK inhibitors in prolonging the PFS of the subgroup of patients with CNS metastases. Drug-specific comparison results demonstrated that lorlatinib was the most effective in prolonging PFS, followed by brigatinib, alectinib, ensartinib, ceritinib, crizotinib, and chemotherapy. While lorlatinib was superior to brigatinib for PFS in the overall patient population, no significant difference between the two was found in the subgroup of patients with CNS metastases. These results can serve as a foundation for basic, clinical, and translational research and guide clinical oncologists in developing individualized treatment strategies for patients with ALK-p, ALK inhibitor-naive advanced NSCLC.

Direct GDP-KRASG12C inhibitors and mechanisms of resistance: the tip of the iceberg

Kirsten rat sarcoma viral oncogene homolog mutations are observed in 25% of lung adenocarcinoma and 40% of these are G12C mutations. Historically, no approved targeted agents were available for patients with any KRAS mutation, and response rates to standard-of-care therapies were suboptimal. Newly developed inhibitors directed toward KRAS^G12C have been successful in clinical trials with overall response rates ranging between 32% and 46%, and two FDA approvals were granted in May 2021 and December 2022 as second-line or later monotherapies. However, rapid tumor resistance complicates their use as a monotherapy. With the rapid development of this novel class of inhibitors, it is important to discern the different types of tumor resistance that may arise and how each can differently contribute to tumor growth and survival. G12C inhibitor resistance is under investigation and combinations of therapies with G12C inhibitors have been proposed. Much of this insight is gleaned from preclinical investigations, as our knowledge of clinical resistance is in its infancy. In this review, we summarize the preclinical development of KRAS^G12C inhibitors, their clinical evaluations, different types of resistance mechanisms to these compounds, and ways of overcoming them. Finally, we underscore the importance of basic and translational investigations of these molecules in a landscape where their clinical evaluations garner the most attention, and we set the stage for what is to come.

Hallmarks of Anaplastic Lymphoma Kinase Inhibitors with Its Quick Emergence of Drug Resistance

Anaplastic lymphoma kinase (ALK) is one of the most popular targets for anticancer therapies. In the past decade, the use of anaplastic lymphoma tyrosine kinase inhibitors (ALK-TKIs), including crizotinib and ceritinib, has been a reliable and standard options for patients with lung cancer, particularly for patients with nonsmall cell lung carcinoma. ALK-targeted therapies initially benefit the patients, yet, resistance eventually occurs. Therefore, resistance mechanisms of ALK-TKIs and the solutions have become a formidable challenge in the development of ALK inhibitors. In this review, based on the knowledge of reported ALK inhibitors, we illustrated the crystal structures of ALK, summarized the resistance mechanisms of ALK-targeted drugs, and proposed potential therapeutic strategies to prevent or overcome the resistance.

Non-Small Cell Lung Cancer Targeted Therapy: Drugs and Mechanisms of Drug Resistance

The advent of precision medicine has brought light to the treatment of non-small cell lung cancer (NSCLC), expanding the options for patients with advanced NSCLC by targeting therapy through genetic and epigenetic cues. Tumor driver genes in NSCLC patients have been uncovered one by one, including epidermal growth factor receptor (EGFR), mesenchymal lymphoma kinase (ALK), and receptor tyrosine kinase ROS proto-oncogene 1 (ROS1) mutants. Antibodies and inhibitors that target the critical gene-mediated signaling pathways that regulate tumor growth and development are anticipated to increase patient survival and quality of life. Targeted drugs continue to emerge, with as many as two dozen approved by the FDA, and chemotherapy and targeted therapy have significantly improved patient prognosis. However, resistance due to cancer drivers' genetic alterations has given rise to significant challenges in treating patients with metastatic NSCLC. Here, we summarized the main targeted therapeutic sites of NSCLC drugs and discussed their resistance mechanisms, aiming to provide new ideas for follow-up research and clues for the improvement of targeted drugs.

Coexistence of anaplastic lymphoma kinase rearrangement in lung adenocarcinoma harbouring epidermal growth factor receptor mutation: A single-center study

BACKGROUND

Accumulating evidences confirm that epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) rearrangement have coexisted in lung adenocarcinoma (LUAD). However, Its biological mechanism, clinicopathological features, and optimization of targeted drugs have not yet been completely elucidated.

AIM

To explore the clinical profile of LUAD patients with co-mutations of EGFR and ALK genes, with hopes of scientifically guiding similar patients towards selected, targeted drugs.

METHODS

Two hundred and thirty-seven LUAD patients were enrolled. EGFR mutations were detected by the amplification refractory mutation system-peptide nucleic acid technique, while the expression of ALK rearrangement was screened by the 5′/3′ imbalance strategy for reverse transcription followed by quantitative polymerase chain reaction analysis. The clinicopathological features of these patients were analysed retrospectively, and the follow-up data were collected.

RESULTS

There were six cases with co-mutations of EGFR and ALK genes, which were more common in women, non-smoking and stage IV LUAD patients with bone metastasis, hence a positive rate of 2.53% (6/237). EGFR-tyrosine kinase inhibitors (EGFR-TKIs) were their preferred drugs for targeted therapy in these patients, with progression-free survival ranging from two months to six months.

CONCLUSION

In Gannan region, the positive rate of co-mutations of EGFR and ALK genes in LUAD patients is relatively high, and the co-mutations are more common in women, non-smoking and stage IV patients with bone metastasis. These patients prefer EGFR-TKIs as their preferred targeted drugs, but the therapeutic effect is not good. EGFR/ALK dual-TKIs may be more effective targeted drugs, which needs further study.

PI3Kβ inhibition enhances ALK-inhibitor sensitivity in ALK-rearranged lung cancer

Treatment with anaplastic lymphoma kinase (ALK) inhibitors significantly improves outcome for non-small-cell lung cancer (NSCLC) patients with ALK-rearranged tumors. However, clinical resistance typically develops over time and, in the majority of cases, resistance mechanisms are ALK-independent. We generated tumor cell cultures from multiple regions of an ALK-rearranged clinical tumor specimen and deployed functional drug screens to identify modulators of ALK-inhibitor response. This identified a role for PI3Kβ and EGFR inhibition in sensitizing the response regulating resistance to ALK inhibition. Inhibition of ALK elicited activation of EGFR, and subsequent MAPK and PI3K-AKT pathway reactivation. Sensitivity to ALK targeting was enhanced by inhibition or knockdown of PI3Kβ. In ALK-rearranged primary cultures, the combined inhibition of ALK and PI3Kβ prevented the EGFR-mediated ALK-inhibitor resistance, and selectively targeted the cancer cells. The combinatorial effect was seen also in the background of TP53 mutations and in epithelial-to-mesenchymal transformed cells. In conclusion, combinatorial ALK- and PI3Kβ-inhibitor treatment carries promise as a treatment for ALK-rearranged NSCLC.

Small-molecule inhibitors, immune checkpoint inhibitors, and more: FDA-approved novel therapeutic drugs for solid tumors from 1991 to 2021

The United States Food and Drug Administration (US FDA) has always been a forerunner in drug evaluation and supervision. Over the past 31 years, 1050 drugs (excluding vaccines, cell-based therapies, and gene therapy products) have been approved as new molecular entities (NMEs) or biologics license applications (BLAs). A total of 228 of these 1050 drugs were identified as cancer therapeutics or cancer-related drugs, and 120 of them were classified as therapeutic drugs for solid tumors according to their initial indications. These drugs have evolved from small molecules with broad-spectrum antitumor properties in the early stage to monoclonal antibodies (mAbs) and antibody‒drug conjugates (ADCs) with a more precise targeting effect during the most recent decade. These drugs have extended indications for other malignancies, constituting a cancer treatment system for monotherapy or combined therapy. However, the available targets are still mainly limited to receptor tyrosine kinases (RTKs), restricting the development of antitumor drugs. In this review, these 120 drugs are summarized and classified according to the initial indications, characteristics, or functions. Additionally, RTK-targeted therapies and immune checkpoint-based immunotherapies are also discussed. Our analysis of existing challenges and potential opportunities in drug development may advance solid tumor treatment in the future.

The Landscape of ALK-Rearranged Non-Small Cell Lung Cancer: A Comprehensive Review of Clinicopathologic, Genomic Characteristics, and Therapeutic Perspectives

Simple Summary

In recent years, prognosis of non-small cell lung cancer (NSCLC) patients significantly improved thanks to the introduction of tyrosine kinase inhibitors (TKIs) in clinical practice. ALK-rearranged NSCLC patients benefit from treatment with ALK inhibitors (ALK-i), which have shown a greater efficacy and a better intracranial activity than chemotherapy. Comparative studies between next-generation ALK-i are still lacking and clinicians are looking for reliable tools to determine which drug suits best for each patient. The aim of this review is to deepen the role of clinical and pathological characteristics influencing patients’ prognosis during treatment with ALK-i and to provide an overview of molecular mechanisms of ALK-i resistance. In this setting, liquid biopsy may play an important role in predicting tumor response and monitoring resistance mutations. We will summarize ongoing trials developing new ALK-i or combinations between ALK-i and other agents, which may represent future scenarios in the field of NSCLC research.

Abstract

During the last decade, the identification of oncogenic driver mutations and the introduction of tyrosine kinase inhibitors (TKIs) in daily clinical practice have substantially revamped the therapeutic approach of oncogene-addicted, non-small cell lung cancer (NSCLC). Rearrangements in the anaplastic lymphoma kinase (ALK) gene are detected in around 3–5% of all NSCLC patients. Following the promising results of Crizotinib, a first-generation ALK inhibitor (ALK-i), other second-generation and more recently third-generation TKIs have been developed and are currently a landmark in NSCLC treatment, leading to a significant improvement in patients prognosis. As clinical trials have already demonstrated high efficacy of each ALK-i, both in terms of systemic and intracranial disease control, comparative studies between second and third generation ALK-i are still lacking, and primary or secondary ALK-i resistance inevitably limit their efficacy. Resistance to ALK-i can be due to ALK-dependent or ALK-independent mechanisms, including the activation of bypass signaling pathways and histological transformation: these findings may play an important role in the future to select patients’ subsequent therapy. This review aims to provide an overview of underlying molecular alterations of ALK-i resistance and point out promising role of liquid biopsy in predicting tumor response and monitoring resistance mutations. The purpose of this review is also to summarize current approval for ALK-rearranged NSCLC patients, to help clinicians in making decisions on therapeutic sequence, and to deepen the role of clinicopathological and genomic characteristics influencing patients’ prognosis during treatment with ALK-i.

3D-QSAR and Docking Studies on Pyrimidine Derivatives of Second-Generation ALK Inhibitors

Anaplastic lymphoma kinase (ALK) is a promising target for the treatment of non-small cell lung cancer. Under crizotinib treatment, drug resistance and progressive disease appeared after the point mutations arising in the kinase domain of ALK. Second-generation ALK inhibitors can solve the deficiencies of the first generation, especially the drug resistance in cancer chemotherapy. Ceritinib (LDK378), a pyrimidine derivative, for example, can inhibit the activity of ALK with an IC50 value of 40.7 nmol/L, and can experience disease progression after initial treatment with crizotinib. Unfortunately, clear structure–activity relationships have not been identified to date, impeding the rational design of future compounds possessing ALK inhibition activity. To explore interesting insights into the structures of pyrimidine derivatives that influence the activities of the second-generation ALK inhibitors, three-dimensional quantitative structure–activity relationship (3D-QSAR) and molecular docking were performed on a total of 45 derivatives of pyrimidine. Comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) techniques were used to generate 3D-QSAR models. CoMFA and CoMSIA were performed using the Sybyl X 2.0 package. Molecular docking analysis was performed using the Surflex-Dock module in SYBYL-X 2.0 package. We found in the CoMFA model that the non-cross-validated r2 value was 0.998, the cross-validated q 2 value was 0.663, and the F statistic value was 2,401.970, while the r2 value was 0.988; q 2 value was 0.730, and F value was 542.933 in CoMSIA models, suggesting the good predictability of the CoMFA and CoMSIA models. 3D contour maps and docking results suggested that different groups on the core parts of the compounds could enhance the biological activities. Based on these results, the established 3D-QSAR models and the binding structures of ALK inhibitors obtained favor the prediction of the activity of new inhibitors and will be helpful in the reasonable design of ALK inhibitors in the future.

Fibroblast growth factor receptor 3 overexpression mediates ALK inhibitor resistance in ALK-rearranged non-small cell lung cancer

The rearrangement of anaplastic lymphoma kinase (ALK) occurs in 3%‐5% of patients with non–small cell lung cancer (NSCLC) and confers sensitivity to ALK–tyrosine kinase inhibitors (TKIs). For the treatment of patients with ALK‐rearranged NSCLC, various additional ALK‐TKIs have been developed. Ceritinib is a second‐generation ALK‐TKI and has shown great efficacy in the treatment of patients with both newly diagnosed and crizotinib (a first‐generation ALK‐TKI)‐refractory ALK‐rearranged NSCLC. However, tumors can also develop ceritinib resistance. This may result from secondary ALK mutations, but other mechanisms responsible for this have not been fully elucidated. In this study, we explored the mechanisms of ceritinib resistance by establishing ceritinib‐resistant, echinoderm microtubule‐associated protein‐like 4 (EML4)‐ALK–positive H3122 cells and ceritinib‐resistant patient‐derived cells. We identified a mechanism of ceritinib resistance induced by bypass signals that is mediated by the overexpression and activation of fibroblast growth factor receptor 3 (FGFR3). FGFR3 knockdown by small hairpin RNA or treatment with FGFR inhibitors was found to resensitize the resistant cells to ceritinib in vitro and in vivo. FGFR ligands from either human serum or fetal bovine serum were able to activate FGFR3 and induce ceritinib resistance. A detailed analysis of ceritinib‐resistant patient‐derived specimens confirmed that tyrosine‐protein kinase Met (cMET) amplification induces ceritinib resistance. Amplified cMET counteractivated EGFR and/or Her3 and induced ceritinib resistance. These results reveal multiple ceritinib resistance mechanisms and suggest that ceritinib resistance might be overcome by identifying precise resistance mechanisms.

The multi-molecular mechanisms of tumor-targeted drug resistance in precision medicine

Clinically, cancer drug therapy is still dominated by chemotherapy drugs. Although the emergence of targeted drugs has greatly improved the survival rate of patients with advanced cancer, drug resistance has always been a difficult problem in clinical cancer treatment. At the current level of medicine, most drugs cannot escape the fate of drug resistance. With the emergence and development of gene detection, liquid biopsy ctDNA technology, and single-cell sequencing technology, the molecular mechanism of tumor drug resistance has gradually emerged. Drugs can also be updated in response to drug resistance mechanisms and bring higher survival benefits. The use of new drugs often leads to new mechanisms of resistance. In this review, the multi-molecular mechanisms of drug resistance are introduced, and the overcoming of drug resistance is discussed from the perspective of the tumor microenvironment.

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.

Review of Therapeutic Strategies for Anaplastic Lymphoma Kinase-Rearranged Non-Small Cell Lung Cancer

Simple Summary

Anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer (NSCLC) was first reported in 2007. Following the development of crizotinib as a tyrosine kinase inhibitor (TKI) targeting ALK, the treatment of advanced NSCLC with ALK-rearrangements has made remarkable progress. Currently, there are five ALK-TKIs approved by the FDA, and the development of new agents, including fourth-generation TKI, is ongoing. Clinical trials with angiogenesis inhibitors and immune checkpoint inhibitors are also underway, and further progress in the treatment of ALK-rearranged advanced NSCLC is expected. The purpose of this manuscript is to provide information on the recent clinical trials of ALK-TKIs, angiogenesis inhibitors, immune checkpoint inhibitors, and chemotherapy, to describe tissue and liquid biopsy as a method to investigate the mechanisms of resistance against ALK-TKIs and suggest a proposed treatment algorithm.

Abstract

Non-small cell lung cancer (NSCLC) with anaplastic lymphoma kinase rearrangement (ALK) was first reported in 2007. ALK-rearranged NSCLC accounts for about 3–8% of NSCLC. The first-line therapy for ALK-rearranged advanced NSCLC is tyrosine kinase inhibitors (TKI) targeting ALK. Following the development of crizotinib, the first ALK-TKI, patient prognosis has been greatly improved. Currently, five TKIs are approved by the FDA. In addition, clinical trials of the novel TKI, ensartinib, and fourth-generation ALK-TKI for compound ALK mutation are ongoing. Treatment with angiogenesis inhibitors and immune checkpoint inhibitors is also being studied. However, as the disease progresses, cancers tend to develop resistance mechanisms. In addition to ALK mutations, other mechanisms, including the activation of bypass signaling pathways and histological transformation, cause resistance, and the identification of these mechanisms is important in selecting subsequent therapy. Studies on tissue and liquid biopsy have been reported and are expected to be useful tools for identifying resistance mechanisms. The purpose of this manuscript is to provide information on the recent clinical trials of ALK-TKIs, angiogenesis inhibitors, immune checkpoint inhibitors, and chemotherapy to describe tissue and liquid biopsy as a method to investigate the mechanisms of resistance against ALK-TKIs and suggest a proposed treatment algorithm.

Real-world circulating tumor DNA analysis depicts resistance mechanism and clonal evolution in ALK inhibitor-treated lung adenocarcinoma patients

Background

Sequential treatment with different generations of anaplastic lymphoma kinase (ALK) inhibitors have been widely applied to ALK-positive lung cancer; however, resistance mutations inevitably developed. Further characterization of ALK resistance mutations may provide key guidance to subsequent therapies. Here we explored the emergence of secondary ALK mutations during sequential ALK tyrosine kinase inhibitor (TKI) treatment in a real-world study of Chinese lung adenocarcinoma (ADC) patients.

Methods

A clinical-genomic database was queried for lung ADC patients with at least one ALK inhibitor treatment and at least one plasma sample collected following ALK inhibitor treatment. Targeted genome profiling was performed with a 139-gene panel in baseline tumor tissue and serial plasma samples of patients.

Results

A total of 116 patients met inclusion criteria. ALK G1202R was more common in patients with echinoderm microtubule-associated protein-like 4 (EML4)-ALK v3 fusion, whereas ALK L1196M was more common in v1. TP53 mutant patients were significantly associated with harboring multiple ALK resistance mutations (P = 0.03) and v3+/TP53 mutant patients had the highest rate of multiple ALK resistance mutations. The sequential use of ALK TKI led to an increased incidence of concurrent ALK mutations along the lines of therapies. Alectinib had a lower rate (9%) harboring ALK resistance mutation as first-line ALK TKI compared with crizotinib (36%). ALK compound mutations identified included ALK D1203N/L1196M, ALK G1202R/L1196M, and ALK G1202R/F1174C, which may be lorlatinib resistant. Using paired pretreatment and post-treatment samples, we identified several ALK-independent resistance-related genetic alterations, including PTPRD and CNKN2A/B loss, MYC, MYCN and KRAS amplification, and EGFR^19del.

Conclusions

Sequential postprogression plasma profiling revealed that increased lines of ALK inhibitors can accelerate the accumulation of ALK resistance mutations and may lead to treatment-refractory compound ALK mutations. The selection for optimal first-line TKI is very important to achieve a more efficacious long-term strategy and prevent the emergence of on-target resistance, which may provide guidance for clinical decision making.

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ALK resistance mutations were differentially enriched in the setting of EML4-ALK v1/v3 and TP53 status.

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Serial liquid biopsies NGS depicted accumulation of multiple ALK secondary mutations during sequential ALK treatments.

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Several lorlatinib-resistant ALK compound mutations and ALK-independent resistance genetic alterations were identified.

Utility of the Ba/F3 cell system for exploring on-target mechanisms of resistance to targeted therapies for lung cancer

Molecular targeted therapies are the standard of care for front‐line treatment of metastatic non‐small‐cell lung cancers (NSCLCs) harboring driver gene mutations. However, despite the initial dramatic responses, the emergence of acquired resistance is inevitable. Acquisition of secondary mutations in the target gene (on‐target resistance) is one of the major mechanisms of resistance. The mouse pro‐B cell line Ba/F3 is dependent on interleukin‐3 for survival and proliferation. Upon transduction of a driver gene, Ba/F3 cells become independent of interleukin‐3 but dependent on the transduced driver gene. Therefore, the Ba/F3 cell line has been a popular system to generate models with oncogene dependence and vulnerability to specific targeted therapies. These models have been used to estimate oncogenicity of driver mutations or efficacies of molecularly targeted drugs. In addition, Ba/F3 models, together with N‐ethyl‐N‐nitrosourea mutagenesis, have been used to derive acquired resistant cells to investigate on‐target resistance mechanisms. Here, we reviewed studies that used Ba/F3 models with EGFR mutations, ALK/ROS1/NTRK/RET fusions, MET exon 14 skipping mutations, or KRAS G12C mutations to investigate secondary/tertiary drug resistant mutations. We determined that 68% of resistance mutations reproducibly detected in clinical cases were also found in Ba/F3 models. In addition, sensitivity data generated with Ba/F3 models correlated well with clinical responses to each drug. Ba/F3 models are useful to comprehensively identify potential mutations that induce resistance to molecularly targeted drugs and to explore drugs to overcome the resistance.

Multimodal platform for assessing drug distribution and response in clinical trials

BACKGROUND

Response to targeted therapy varies between patients for largely unknown reasons. Here, we developed and applied an integrative platform using mass spectrometry imaging (MSI), phosphoproteomics, and multiplexed tissue imaging for mapping drug distribution, target engagement, and adaptive response to gain insights into heterogeneous response to therapy.

METHODS

Patient-derived xenograft (PDX) lines of glioblastoma were treated with adavosertib, a Wee1 inhibitor, and tissue drug distribution was measured with MALDI-MSI. Phosphoproteomics was measured in the same tumors to identify biomarkers of drug target engagement and cellular adaptive response. Multiplexed tissue imaging was performed on sister sections to evaluate spatial co-localization of drug and cellular response. The integrated platform was then applied on clinical specimens from glioblastoma patients enrolled in the phase 1 clinical trial.

RESULTS

PDX tumors exposed to different doses of adavosertib revealed intra- and inter-tumoral heterogeneity of drug distribution and integration of the heterogeneous drug distribution with phosphoproteomics and multiplexed tissue imaging revealed new markers of molecular response to adavosertib. Analysis of paired clinical specimens from patients enrolled in the phase 1 clinical trial informed the translational potential of the identified biomarkers in studying patient's response to adavosertib.

CONCLUSIONS

The multimodal platform identified a signature of drug efficacy and patient-specific adaptive responses applicable to preclinical and clinical drug development. The information generated by the approach may inform mechanisms of success and failure in future early phase clinical trials, providing information for optimizing clinical trial design and guiding future application into clinical practice.

Dual target inhibitors based on EGFR: Promising anticancer agents for the treatment of cancers (2017-)

The EGFR family play a significant role in cell signal transduction and their overexpression is implicated in the pathogenesis of numerous human solid cancers. Inhibition of the EGFR-mediated signaling pathways by EGFR inhibitors is a widely used strategy for the treatment of cancers. In most cases, the EGFR inhibitors used in clinic were only effective when the cancer cells harbored specific activating EGFR mutations which appeared to preserve the ligand-dependency of receptor activation but altered the pattern of downstream signaling pathways. Moreover, cancer is a kind of multifactorial disease, and therefore manipulating a single target may result in treatment failure. Although drug combinations for the treatment of cancers proved to be successful, the use of two or more drugs concurrently still was a challenge in clinical therapy owing to various dose-limiting toxicities and drug-drug interactions caused by pharmacokinetic profiles changed. Therefore, a single drug targeting two or multiple targets could serve as an effective strategy for the treatment of cancers. In recent, drugs with diverse pharmacological effects have been shown to be more advantageous than combination therapies due to their lower incidences of side effects and more resilient therapies. Accordingly, dual target-single-agent strategy has become a popular field for cancer treatment, and researchers became more and more interest in the development of novel dual-target drugs in recent years. In this review, we briefly introduce the EGFR family proteins and synergisms between EGFR and other anticancer targets, and summarizes the development of potential dual target inhibitors based on wild-type and/or mutant EGFR for the treatment of solid cancers in the past five years. Additionally, the rational design and SARs of these dual target agents are also presented in detailed, which will lay a significant foundation for the further development of novel EGFR-based dual inhibitors with excellent druggability.

Novel germline MET pathogenic variants in French patients with papillary renal cell carcinomas type I

Hereditary papillary renal cell carcinoma (HPRC) is a rare inherited renal cancer syndrome characterized by bilateral and multifocal papillary type 1 renal tumors (PRCC1). Activating germline pathogenic variants of MET gene were identified in HPRC families. We reviewed the medical and molecular records of a large French series of 158 patients screened for MET oncogenic variants. MET pathogenic and likely pathogenic variants rate was 12.4% with 40.6% among patients with familial PRCC1 and 5% among patients with sporadic PRCC1. The phenotype in cases with MET pathogenic and likely pathogenic variants was characteristic: PRCC1 tumors were mainly bilateral (84.3%) and multifocal (87.5%). Histologically, six out of seven patients with MET pathogenic variant harboured biphasic squamoid alveolar PRCC. Genetic screening identified one novel pathogenic variant MET c.3389T>C, p.(Leu1130Ser) and three novel likely pathogenic variants: MET c.3257A>T, p.(His1086Leu); MET c.3305T>C, p.(Ile1102Thr) and MET c.3373T>G, p.(Cys1125Gly). Functional assay confirmed their oncogenic effect as they induced an abnormal focus formation. The genotype-phenotype correlation between MET pathogenic variants and PRCC1 presentation should encourage to widen the screening, especially toward non-familial PRCC1. This precise phenotype also constitutes a strong argument for the classification of novel missense variants within the tyrosine kinase domain when functional assays aren't accessible. This article is protected by copyright. All rights reserved.

Resistance to Targeted Agents Used to Treat Paediatric ALK-Positive ALCL

Simple Summary

In general, the non-Hodgkin lymphoma (NHL), anaplastic large cell lymphoma (ALCL) diagnosed in childhood has a good survival outcome when treated with multi-agent chemotherapy. However, side effects of treatment are common, and outcomes are poorer after relapse, which occurs in up to 30% of cases. New drugs are required that are more effective and have fewer side effects. Targeted therapies are potential solutions to these problems, however, the development of resistance may limit their impact. This review summarises the potential resistance mechanisms to these targeted therapies.

Abstract

Non-Hodgkin lymphoma (NHL) is the third most common malignancy diagnosed in children. The vast majority of paediatric NHL are either Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL), anaplastic large cell lymphoma (ALCL), or lymphoblastic lymphoma (LL). Multi-agent chemotherapy is used to treat all of these types of NHL, and survival is over 90% but the chemotherapy regimens are intensive, and outcomes are generally poor if relapse occurs. Therefore, targeted therapies are of interest as potential solutions to these problems. However, the major problem with all targeted agents is the development of resistance. Mechanisms of resistance are not well understood, but increased knowledge will facilitate optimal management strategies through improving our understanding of when to select each targeted agent, and when a combinatorial approach may be helpful. This review summarises currently available knowledge regarding resistance to targeted therapies used in paediatric anaplastic lymphoma kinase (ALK)-positive ALCL. Specifically, we outline where gaps in knowledge exist, and further investigation is required in order to find a solution to the clinical problem of drug resistance in ALCL.

Cyclin-dependent kinase 4 upregulation mediates acquired resistance of dabrafenib plus trametinib in BRAF V600E-mutated lung cancer

Background

Combination therapy with the B-Raf inhibitor, dabrafenib, and the MEK inhibitor, trametinib (DT) is commonly used to treat patients with B-Raf proto-oncogene, serine/threonine kinase V600E (BRAF V600E)-mutated non-small cell lung cancer (NSCLC). However, the mechanisms through which cancer develops DT resistance are unclear. Here, we investigated new mechanisms underlying acquired DT-resistant NSCLC with the BRAF V600E mutation.

Methods

We compared genomic signatures before and after DT treatment in patients with NSCLC.

Results

Two of four patients treated with DT developed carcinomatous pleuritis within 3 months. Target DNA sequencing and quantitative polymerase chain reaction (PCR) analyses revealed the increased expression level of cyclin-dependent kinase 4 (CDK4). We also found prominent protein expression of CDK4 after DT treatment. Induction of CDK4 expression in a cell line derived from a patient with the BRAF V600E mutation resulted in partial resistance to dabrafenib.

Conclusions

Our findings suggest a possible relationship between CDK4 upregulation and acquired resistance to DT therapy.