Rationale for co-targeting IGF-1R and ALK in ALK fusion-positive lung cancer

Targeting ALK receptors in non-small cell lung cancer: what is the road ahead?

INTRODUCTION

Anaplastic lymphoma kinase (ALK) gene-rearrangements are identified in about 3-5% of non-small cell lung cancers (NSCLC), and ALK-rearranged NSCLC is to be considered an oncogene-addicted cancer with peculiar clinical characteristics.

AREAS COVERED

Several ALK inhibitors have been studied and approved for use in the treatment of advanced ALK-rearranged NSCLC with reported superiority in terms of efficacy and safety profile compared with chemotherapy. Second- and third-generation ALK inhibitors (alectinib, brigatinib, and lorlatinib) offer to NSCLC patients a clinically meaningful prolongment of survival with a very good quality of life profile. However, resistances to these agents always occur, with less satisfying options for second-line treatments. Direct comparisons among these agents are not available, and the choice among brigatinib, alectinib, and lorlatinib as first-line treatment remains challenging. Very recently, alectinib has been demonstrated to improve efficacy outcomes compared with chemotherapy also in resected stage IB-IIIA ALK-rearranged NSCLC, extending the clinical benefit offered by ALK inhibitors also to the adjuvant setting.

EXPERT OPINION

Future development of ALK inhibitors in NSCLC treatment includes the search for optimal management of acquired resistance to first-line treatments and the extension of use of ALK inhibitors also to neoadjuvant and preferably to perioperative setting.

Understanding the treatment response and resistance to targeted therapies in non-small cell lung cancer: clinical insights and perspectives

Lung cancer remains the leading cause of mortality worldwide. Non-small cell lung cancer (NSCLC) is the most common subtype of lung cancer with a generally poor prognosis. In recent years, advances in targeted therapy and sequencing technology have brought significant improvement in the therapeutic outcomes of patients with advanced NSCLC. Targeted inhibitors directed against specific mutated or rearranged oncogenes, such as epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), and receptor tyrosine kinase ROS proto-oncogene 1(ROS1) among others, exhibit promising anti-tumor activity. Unfortunately, some patients develop acquired resistance and disease progression soon after initial remission. Despite the continuous development of new drugs and strategies to overcome drug resistance, it is still a major challenge in the treatment of NSCLC. The landscape of targeted therapy for NSCLC is evolving rapidly in response to the pace of scientific research. This study aimed to provide a comprehensive review of tumor target antigens and agents related to targeted therapy in NSCLC.

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.

RET rearrangement as a mechanism of resistance to ALK-TKI in non-small cell lung cancer patient with EML4-ALK fusion: A case report

Patients with non-small cell lung cancer (NSCLC) and anaplastic lymphoma kinase (ALK) mutations have previously derived substantial benefits from ALK tyrosine kinase inhibitors (ALK-TKIs). However, resistance may develop in some patients. We present a case of co-mutation with anaplastic lymphoma kinase (ALK) and rearranged during transfection (RET)-rearranged NSCLC, representing a novel resistance mechanism to ALK-TKIs, in which the patient exhibited a favorable response to combination therapy with ensartinib and pralsetinib. Notably, the patient survived 12 months without experiencing adverse events, a rare occurrence in ALK-rearranged lung adenocarcinoma cases. This case provides further evidence for the existence of RET rearrangements in ALK-positive lung cancer and their potential treatment response to a combination of ALK inhibitors and pralsetinib. This case underscores that a dual-target therapy involving ALK inhibitors, specifically ensartinib and pralsetinib, could be a viable approach in cases of RET-rearranged lung cancer with concurrent targetable ALK mutations. We propose the consideration of this dual-target approach, specifically employing ensartinib and pralsetinib, in managing RET-rearranged lung cancer coexisting with targetable ALK mutations. Given the potential efficacy of these treatments, it is imperative to proactively conduct molecular profiling tests in NSCLC patients upon the emergence of resistance.

Concurrent inhibition of ALK and SRC kinases disrupts the ALK lung tumor cell proteome

Precision oncology has revolutionized the treatment of ALK-positive lung cancer with targeted therapies. However, an unmet clinical need still to address is the treatment of refractory tumors that contain drug-induced resistant mutations in the driver oncogene or exhibit resistance through the activation of diverse mechanisms. In this study, we established mouse tumor-derived cell models representing the two most prevalent EML4-ALK variants in human lung adenocarcinomas and characterized their proteomic profiles to gain insights into the underlying resistance mechanisms. We showed that Eml4-Alk variant 3 confers a worse response to ALK inhibitors, suggesting its role in promoting resistance to targeted therapy. In addition, proteomic analysis of brigatinib-treated cells revealed the upregulation of SRC kinase, a protein frequently activated in cancer. Co-targeting of ALK and SRC showed remarkable inhibitory effects in both ALK-driven murine and ALK-patient-derived lung tumor cells. This combination induced cell death through a multifaceted mechanism characterized by profound perturbation of the (phospho)proteomic landscape and a synergistic suppressive effect on the mTOR pathway. Our study demonstrates that the simultaneous inhibition of ALK and SRC can potentially overcome resistance mechanisms and enhance clinical outcomes in ALK-positive lung cancer patients. ONE SENTENCE SUMMARY: Co-targeting ALK and SRC enhances ALK inhibitor response in lung cancer by affecting the proteomic profile, offering hope for overcoming resistance and improving clinical outcomes.

Role of Insulin-like Growth Factor-1 Receptor in Tobacco Smoking-Associated Lung Cancer Development

Cancer remains a significant global health concern, with lung cancer consistently leading as one of the most common malignancies. Genetic aberrations involving receptor tyrosine kinases (RTKs) are known to be associated with cancer initiation and development, but RTK involvement in smoking-associated lung cancer cases is not well understood. The Insulin-like Growth Factor 1 Receptor (IGF-1R) is a receptor that plays a critical role in lung cancer development. Its signaling pathway affects the growth and survival of cancer cells, and high expression is linked to poor prognosis and resistance to treatment. Several reports have shown that by activating IGF-1R, tobacco smoke-related carcinogens promote lung cancer and chemotherapy resistance. However, the relationship between IGF-1R and cancer is complex and can vary depending on the type of cancer. Ongoing investigations are focused on developing therapeutic strategies to target IGF-1R and overcome chemotherapy resistance. Overall, this review explores the intricate connections between tobacco smoke-specific carcinogens and the IGF-1R pathway in lung carcinogenesis. This review further highlights the challenges in using IGF-1R inhibitors as targeted therapy for lung cancer due to structural similarities with insulin receptors. Overcoming these obstacles may require a comprehensive approach combining IGF-1R inhibition with other selective agents for successful cancer treatment.

Deterministic reprogramming and signaling activation following targeted therapy in non-small cell lung cancer driven by mutations or oncogenic fusions

INTRODUCTION

Targeted therapy is used to treat lung adenocarcinoma caused by epidermal growth factor receptor (EGFR) mutations in the tyrosine kinase domain and rare subtypes (<5%) of non-small cell lung cancer. These subtypes include fusion oncoproteins like anaplastic lymphoma kinase (ALK), ROS1, rearranged during transfection (RET), and other receptor tyrosine kinases (RTKs). The use of diverse selective oral inhibitors, including those targeting rat sarcoma viral oncogene homolog (KRAS) mutations, has significantly improved clinical responses, extending progression-free and overall survival.

AREAS COVERED

Resistance remains a critical issue in lung adenocarcinoma, notably in EGFR mutant, echinoderm microtubule associated protein-like 4 (EML4)-ALK fusion, and KRAS mutant tumors, often associated with epithelial-to-mesenchymal transition (EMT).

EXPERT OPINION

Despite advancements in next generation EGFR inhibitors and EML4-ALK therapies with enhanced brain penetrance and identifying resistance mutations, overcoming resistance has not been abated. Various strategies are being explored to overcome this issue to achieve prolonged cancer remission and delay resistance. Targeting yes-associated protein (YAP) and the mechanisms associated with YAP activation through Hippo-dependent or independent pathways, is desirable. Additionally, the exploration of liquid-liquid phase separation in fusion oncoproteins forming condensates in the cytoplasm for oncogenic signaling is a promising field for the development of new treatments.

Differential network analysis of ROS1 inhibitors reveals lorlatinib polypharmacology through co-targeting PYK2

Multiple tyrosine kinase inhibitors (TKIs) are often developed for the same indication. However, their relative overall efficacy is frequently incompletely understood and they may harbor unrecognized targets that cooperate with the intended target. We compared several ROS1 TKIs for inhibition of ROS1-fusion-positive lung cancer cell viability, ROS1 autophosphorylation and kinase activity, which indicated disproportionately higher cellular potency of one TKI, lorlatinib. Quantitative chemical and phosphoproteomics across four ROS1 TKIs and differential network analysis revealed that lorlatinib uniquely impacted focal adhesion signaling. Functional validation using pharmacological probes, RNA interference, and CRISPR-Cas9 knockout uncovered a polypharmacology mechanism of lorlatinib by dual targeting ROS1 and PYK2, which form a multiprotein complex with SRC. Rational multi-targeting of this complex by combining lorlatinib with SRC inhibitors exhibited pronounced synergy. Taken together, we show that systems pharmacology-based differential network analysis can dissect mixed canonical/non-canonical polypharmacology mechanisms across multiple TKIs enabling the design of rational drug combinations.

Unraveling the Potential of ALK-Targeted Therapies in Non-Small Cell Lung Cancer: Comprehensive Insights and Future Directions

Background and Objective: This review comprehensively explores the intricate landscape of anaplastic lymphoma kinase (ALK), focusing specifically on its pivotal role in non-small cell lung cancer (NSCLC). Tracing ALK's discovery, from its fusion with nucleolar phosphoprotein (NPM)-1 in anaplastic large cell non-Hodgkin's lymphoma (ALCL) in 1994, the review elucidates the subsequent impact of ALK gene alterations in various malignancies, including inflammatory myofibroblastoma and NSCLC. Approximately 3-5% of NSCLC patients exhibit complex ALK rearrangements, leading to the approval of six ALK-tyrosine kinase inhibitors (TKIs) by 2022, revolutionizing the treatment landscape for advanced metastatic ALK + NSCLC. Notably, second-generation TKIs such as alectinib, ceritinib, and brigatinib have emerged to address resistance issues initially associated with the pioneer ALK-TKI, crizotinib. Methods: To ensure comprehensiveness, we extensively reviewed clinical trials on ALK inhibitors for NSCLC by 2023. Additionally, we systematically searched PubMed, prioritizing studies where the terms "ALK" AND "non-small cell lung cancer" AND/OR "NSCLC" featured prominently in the titles. This approach aimed to encompass a spectrum of relevant research studies, ensuring our review incorporates the latest and most pertinent information on innovative and alternative therapeutics for ALK + NSCLC. Key Content and Findings: Beyond exploring the intricate details of ALK structure and signaling, the review explores the convergence of ALK-targeted therapy and immunotherapy, investigating the potential of immune checkpoint inhibitors in ALK-altered NSCLC tumors. Despite encouraging preclinical data, challenges observed in trials assessing combinations such as nivolumab-crizotinib, mainly due to severe hepatic toxicity, emphasize the necessity for cautious exploration of these novel approaches. Additionally, the review explores innovative directions such as ALK molecular diagnostics, ALK vaccines, and biosensors, shedding light on their promising potential within ALK-driven cancers. Conclusions: This comprehensive analysis covers molecular mechanisms, therapeutic strategies, and immune interactions associated with ALK-rearranged NSCLC. As a pivotal resource, the review guides future research and therapeutic interventions in ALK-targeted therapy for NSCLC.

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.

Role of human epidermal growth factor receptor 3 in treatment resistance of anaplastic lymphoma kinase translocated non-small cell lung cancer

BACKGROUND

ALK tyrosine kinase inhibitors (TKI) have revolutionized the treatment of ALK+ non-small cell lung cancer (NSCLC), and therapy resistance occurs in virtually all patients. Multiple TKI resistance mechanisms have been characterized, including ERBB receptor coactivation. In this study, we investigated the role of HER3 in ALK TKI resistance.

METHODS

In vitro studies were carried out using ALK+ NSCLC cell lines H3122, H2228, and DFCI032. Pharmacological co-targeting of ALK and HER3 was investigated with ALK and ERBB TKIs, and HER3 knockdown was achieved using the CRISPR-Cas9 system. Co-localization of ALK and HER3 was investigated by immunoprecipitation (IP) and proximity ligation assay (PLA) in vitro and in vivo using six ALK+ NSCLC tumor samples.

RESULTS

In all tested cell lines, combined targeting with ALK and pan-ERBB TKI resulted in marked inhibition of colony formation and long-term (72 h) downregulation of pAKT levels. HER3 knockdown resulted in multiple effects on ALK+ cell lines, including the downregulation of ALK expression and visible morphological changes (H2228). Co-immunoprecipitation (IP) and proximation ligation assay (PLA) experiments provided evidence that both ALK and HER3 could interact in vitro, and this finding was verified by PLA using ALK+ NSCLC tumors.

CONCLUSIONS

This study provides evidence that HER3 may mediate TKI resistance in ALK+ NSCLC. Interestingly, we were able to show that both translocated ALK and HER3 could interact. Joint targeting of ALK and HER3 could be further investigate in ALK+ NSCLC.

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.

Targeting drug-tolerant cells: A promising strategy for overcoming acquired drug resistance in cancer cells

Drug resistance remains the greatest challenge in improving outcomes for cancer patients who receive chemotherapy and targeted therapy. Surmounting evidence suggests that a subpopulation of cancer cells could escape intense selective drug treatment by entering a drug-tolerant state without genetic variations. These drug-tolerant cells (DTCs) are characterized with a slow proliferation rate and a reversible phenotype. They reside in the tumor region and may serve as a reservoir for resistant phenotypes. The survival of DTCs is regulated by epigenetic modifications, transcriptional regulation, mRNA translation remodeling, metabolic changes, antiapoptosis, interactions with the tumor microenvironment, and activation of signaling pathways. Thus, targeting the regulators of DTCs opens a new avenue for the treatment of therapy-resistant tumors. In this review, we first provide an overview of common characteristics of DTCs and the regulating networks in DTCs development. We also discuss the potential therapeutic opportunities to target DTCs. Last, we discuss the current challenges and prospects of the DTC-targeting approach to overcome acquired drug resistance. Reviewing the latest developments in DTC research could be essential in discovering of methods to eliminate DTCs, which may represent a novel therapeutic strategy for preventing drug resistance in the future.

ALK fusions in the pan-cancer setting: another tumor-agnostic target?

Anaplastic lymphoma kinase (ALK) alterations (activating mutations, amplifications, and fusions/rearrangements) occur in ~3.3% of cancers. ALK fusions/rearrangements are discerned in >50% of inflammatory myofibroblastic tumors (IMTs) and anaplastic large cell lymphomas (ALCLs), but only in ~0.2% of other cancers outside of non-small cell lung cancer (NSCLC), a rate that may be below the viability threshold of even large-scale treatment trials. Five ALK inhibitors -alectinib, brigatinib, ceritinb, crizotinib, and lorlatinib-are FDA approved for ALK-aberrant NSCLCs, and crizotinib is also approved for ALK-aberrant IMTs and ALCL, including in children. Herein, we review the pharmacologic tractability of ALK alterations, focusing beyond NSCLC. Importantly, the hallmark of approved indications is the presence of ALK fusions/rearrangements, and response rates of ~50-85%. Moreover, there are numerous reports of ALK inhibitor activity in multiple solid and hematologic tumors (e.g., histiocytosis, leiomyosarcoma, lymphoma, myeloma, and colorectal, neuroendocrine, ovarian, pancreatic, renal, and thyroid cancer) bearing ALK fusions/rearrangements. Many reports used crizotinib or alectinib, but each of the approved ALK inhibitors have shown activity. ALK inhibitor activity is also seen in neuroblastoma, which bear ALK mutations (rather than fusions/rearrangements), but response rates are lower (~10-20%). Current data suggests that ALK inhibitors have tissue-agnostic activity in neoplasms bearing ALK fusions/rearrangements.

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.

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.

Transcriptome Analysis of Leg Muscles and the Effects of ALOX5 on Proliferation and Differentiation of Myoblasts in Haiyang Yellow Chickens

Skeletal muscle growth and development from embryo to adult consists of a series of carefully regulated changes in gene expression. This study aimed to identify candidate genes involved in Haiyang Yellow Chickens' growth and to understand the regulatory role of the key gene ALOX5 (arachidonate 5-lipoxygenase) in myoblast proliferation and differentiation. In order to search the key candidate genes in the process of muscle growth and development, RNA sequencing was used to compare the transcriptomes of chicken muscle tissues at four developmental stages and to analyze the effects of ALOX5 gene interference and overexpression on myoblast proliferation and differentiation at the cellular level. The results showed that 5743 differentially expressed genes (DEGs) (|fold change| ≥ 2; FDR ≤ 0.05) were detected by pairwise comparison in male chickens. Functional analysis showed that the DEGs were mainly involved in the processes of cell proliferation, growth, and developmental process. Many of the DEGs, such as MYOCD (Myocardin), MUSTN1 (Musculoskeletal Embryonic Nuclear Protein 1), MYOG (MYOGenin), MYOD1 (MYOGenic differentiation 1), FGF8 (fibroblast growth factor 8), FGF9 (fibroblast growth factor 9), and IGF-1 (insulin-like growth factor-1), were related to chicken growth and development. KEGG pathway (Kyoto Encyclopedia of Genes and Genomes pathway) analysis showed that the DEGs were significantly enriched in two pathways related to growth and development: ECM-receptor interaction (Extracellular Matrix) and MAPK signaling pathway (Mitogen-Activated Protein Kinase). With the extension of differentiation time, the expression of the ALOX5 gene showed an increasing trend, and it was found that interference with the ALOX5 gene could inhibit the proliferation and differentiation of myoblasts and that overexpression of the ALOX5 gene could promote the proliferation and differentiation of myoblasts. This study identified a range of genes and several pathways that may be involved in regulating early growth, and it can provide theoretical research for understanding the regulation mechanism of muscle growth and development of Haiyang Yellow Chickens.

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.

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.

Inhibition of ALK-Signaling Overcomes STRN-ALK-Induced Downregulation of the Sodium Iodine Symporter and Restores Radioiodine Uptake in Thyroid Cells

Background: Radioiodine (RAI) is commonly used for thyroid cancer treatment, although its therapeutic benefits are restricted to iodine-avid tumors. The RAI-refractory disease develops with tumor dedifferentiation involving loss of sodium-iodine symporter (NIS). Thyroid cancers driven by ALK fusions are prone to dedifferentiation, and whether targeted ALK inhibition may enhance RAI uptake in these tumors remains unknown. The aim of this study was to determine the levels of NIS expression during the progression of ALK fusion-driven thyroid cancer, assess the effects of ALK activation on NIS-mediated RAI uptake, and test pharmacological options for its modulation. Methods: The expression of NIS at different stages of ALK-driven carcinogenesis was analyzed using a mouse model of STRN-ALK-driven thyroid cancer. For in vitro experiments, a system of doxycycline-inducible expression of STRN-ALK was generated using PCCL3 normal thyroid cells. The STRN-ALK-induced effects were evaluated with quantitative reverse transcription polymerase chain reaction, Western blot, immunofluorescence, RNA sequencing, and gene sets pathways analyses. RAI uptake was measured using 131I. Treatment experiments were done with FDA-approved ALK inhibitors (crizotinib and ceritinib), MEK inhibitor selumetinib, and JAK1/2 inhibitor ruxolitinib. Results: We found that Nis downregulation occurred early in ALK-driven thyroid carcinogenesis, even at the stage of well-differentiated cancer, with a complete loss in poorly differentiated thyroid carcinomas. Acute STRN-ALK expression in thyroid cells resulted in increased MAPK, JAK/STAT3, and PI3K/AKT/mTOR signaling outputs associated with significant ALK-dependent downregulation of the majority of thyroid differentiation and iodine metabolism/transport genes, including Slc5a5 (Nis), Foxe1, Dio1, Duox1/2, Duoxa2, Glis3, Slc5a8, and Tg. Moreover, STRN-ALK expression in thyroid cells induced a significant loss of membranous NIS and a fourfold decrease of the NIS-mediated RAI uptake, which were reversed by ALK inhibitors crizotinib and ceritinib. In addition, a strong dose-dependent restoration of NIS with its membranous redistribution in STRN-ALK-expressing thyroid cells was observed after inhibition of MAPK signaling with selumetinib, which exhibited a cumulative effect with JAK1/2 inhibitor ruxolitinib. Conclusions: The findings of this preclinical study showed that ALK fusion-induced downregulation of NIS, the prerequisite of RAI refractoriness, could be reversed in thyroid cells by either direct inhibition of ALK or its downstream signaling pathways.

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.

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.

Interactions of melatonin with various signaling pathways: implications for cancer therapy

Melatonin is a neuro-hormone with conserved roles in evolution. Initially synthetized as an antioxidant molecule, it has gained prominence as a key molecule in the regulation of the circadian rhythm. Melatonin exerts its effect by binding to cytoplasmic and intra-nuclear receptors, and is able to regulate the expression of key mediators of different signaling pathways. This ability has led scholars to investigate the role of melatonin in reversing the process of carcinogenesis, a process in which many signaling pathways are involved, and regulating these pathways may be of clinical significance. In this review, the role of melatonin in regulating multiple signaling pathways with important roles in cancer progression is discussed, and evidence regarding the beneficence of targeting malignancies with this approach is presented.

Molecular pathways, resistance mechanisms and targeted interventions in non-small-cell lung cancer

Lung cancer is the leading cause of cancer-related mortality worldwide. The discovery of tyrosine kinase inhibitors effectively targeting EGFR mutations in lung cancer patients in 2004 represented the beginning of the precision medicine era for this refractory disease. This great progress benefits from the identification of driver gene mutations, and after that, conventional and new technologies such as NGS further illustrated part of the complex molecular pathways of NSCLC. More targetable driver gene mutation identification in NSCLC patients greatly promoted the development of targeted therapy and provided great help for patient outcomes including significantly improved survival time and quality of life. Herein, we review the literature and ongoing clinical trials of NSCLC targeted therapy to address the molecular pathways and targeted intervention progress in NSCLC. In addition, the mutations in EGFR gene, ALK rearrangements, and KRAS mutations in the main sections, and the less common molecular alterations in MET, HER2, BRAF, ROS1, RET, and NTRK are discussed. The main resistance mechanisms of each targeted oncogene are highlighted to demonstrate the current dilemma of targeted therapy in NSCLC. Moreover, we discuss potential therapies to overcome the challenges of drug resistance. In this review, we manage to display the current landscape of targetable therapeutic patterns in NSCLC in this era of precision medicine.

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.

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.

Protein tyrosine kinase inhibitor resistance in malignant tumors: molecular mechanisms and future perspective

Protein tyrosine kinases (PTKs) are a class of proteins with tyrosine kinase activity that phosphorylate tyrosine residues of critical molecules in signaling pathways. Their basal function is essential for maintaining normal cell growth and differentiation. However, aberrant activation of PTKs caused by various factors can deviate cell function from the expected trajectory to an abnormal growth state, leading to carcinogenesis. Inhibiting the aberrant PTK function could inhibit tumor growth. Therefore, tyrosine kinase inhibitors (TKIs), target-specific inhibitors of PTKs, have been used in treating malignant tumors and play a significant role in targeted therapy of cancer. Currently, drug resistance is the main reason for limiting TKIs efficacy of cancer. The increasing studies indicated that tumor microenvironment, cell death resistance, tumor metabolism, epigenetic modification and abnormal metabolism of TKIs were deeply involved in tumor development and TKI resistance, besides the abnormal activation of PTK-related signaling pathways involved in gene mutations. Accordingly, it is of great significance to study the underlying mechanisms of TKIs resistance and find solutions to reverse TKIs resistance for improving TKIs efficacy of cancer. Herein, we reviewed the drug resistance mechanisms of TKIs and the potential approaches to overcome TKI resistance, aiming to provide a theoretical basis for improving the efficacy of TKIs.

ALK fusion promotes metabolic reprogramming of cancer cells by transcriptionally upregulating PFKFB3

Anaplastic lymphoma kinase (ALK), a receptor tyrosine kinase of the insulin receptor kinase subfamily, is activated in multiple cancer types through translocation or overexpression. Although several generations of ALK tyrosine kinase inhibitors (TKIs) have been developed for clinic use, drug resistance remains a major challenge. In this study, by quantitative proteomic approach, we identified the glycolytic regulatory enzyme, 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), as a new target of ALK. Expression of PFKFB3 is highly dependent on ALK activity in ALK⁺ anaplastic large cell lymphoma and non-small-cell lung cancer (NSCLC) cells. Notably, ALK and PFKFB3 expressions exhibit significant correlation in clinic ALK⁺ NSCLC samples. We further demonstrated that ALK promotes PFKFB3 transcription through the downstream transcription factor STAT3. Upregulation of PFKFB3 by ALK is important for high glycolysis level as well as oncogenic activity of ALK⁺ lymphoma cells. Finally, targeting PFKFB3 by its inhibitor can overcome drug resistance in cells bearing TKI-resistant mutants of ALK. Collectively, our studies reveal a novel ALK-STAT3-PFKFB3 axis to promote cell proliferation and tumorigenesis, providing an alternative strategy for the treatment of ALK-positive tumors.

A kinase inhibitor screen reveals MEK1/2 as a novel therapeutic target to antagonize IGF1R-mediated antiestrogen resistance in ERα-positive luminal breast cancer

Antiestrogen resistance of breast cancer has been related to enhanced growth factor receptor expression and activation. We have previously shown that ectopic expression and subsequent activation of the insulin-like growth factor-1 receptor (IGF1R) or the epidermal growth factor receptor (EGFR) in MCF7 or T47D breast cancer cells results in antiestrogen resistance. In order to identify novel therapeutic targets to prevent this antiestrogen resistance, we performed kinase inhibitor screens with 273 different inhibitors in MCF7 cells overexpressing IGF1R or EGFR. Kinase inhibitors that antagonized antiestrogen resistance but are not directly involved in IGF1R or EGFR signaling were prioritized for further analyses. Various ALK (anaplastic lymphoma receptor tyrosine kinase) inhibitors inhibited cell proliferation in IGF1R expressing cells under normal and antiestrogen resistance conditions by preventing IGF1R activation and subsequent downstream signaling; the ALK inhibitors did not affect EGFR signaling. On the other hand, MEK (mitogen-activated protein kinase kinase)1/2 inhibitors, including PD0325901, selumetinib, trametinib and TAK733, selectively antagonized IGF1R signaling-mediated antiestrogen resistance but did not affect cell proliferation under normal growth conditions. RNAseq analysis revealed that MEK inhibitors PD0325901 and selumetinib drastically altered cell cycle progression and cell migration networks under IGF1R signaling-mediated antiestrogen resistance. In a group of 219 patients with metastasized ER+ breast cancer, strong pMEK staining showed a significant correlation with no clinical benefit of first-line tamoxifen treatment. We propose a critical role for MEK activation in IGF1R signaling-mediated antiestrogen resistance and anticipate that dual-targeted therapy with a MEK inhibitor and antiestrogen could improve treatment outcome.

IGF-binding proteins secreted by cancer-associated fibroblasts induce context-dependent drug sensitization of lung cancer cells

Cancer-associated fibroblasts (CAFs) in the tumor microenvironment are often linked to drug resistance. Here, we found that coculture with CAFs or culture in CAF-conditioned medium unexpectedly induced drug sensitivity in certain lung cancer cell lines. Gene expression and secretome analyses of CAFs and normal lung-associated fibroblasts (NAFs) revealed differential abundance of insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs), which promoted or inhibited, respectively, signaling by the receptor IGF1R and the kinase FAK. Similar drug sensitization was seen in gefitinib-resistant, EGFR-mutant PC9GR lung cancer cells treated with recombinant IGFBPs. Conversely, drug sensitivity was decreased by recombinant IGFs or conditioned medium from CAFs in which IGFBP5 or IGFBP6 was silenced. Phosphoproteomics and receptor tyrosine kinase (RTK) array analyses indicated that exposure of PC9GR cells to CAF-conditioned medium also inhibited compensatory IGF1R and FAK signaling induced by the EGFR inhibitor osimertinib. Combined small-molecule inhibition of IGF1R and FAK phenocopied the CAF-mediated effects in culture and increased the antitumor effect of osimertinib in mice. Cells that were osimertinib resistant and had MET amplification or showed epithelial-to-mesenchymal transition also displayed residual sensitivity to IGFBPs. Thus, CAFs promote or reduce drug resistance in a context-dependent manner, and deciphering the relationship between the differential content of CAF secretomes and the signaling dependencies of the tumor may reveal effective combination treatment strategies.

Third-generation EGFR and ALK inhibitors: mechanisms of resistance and management

The discoveries of EGFR mutations and ALK rearrangements as actionable oncogenic drivers in non-small-cell lung cancer (NSCLC) has propelled a biomarker-directed treatment paradigm for patients with advanced-stage disease. Numerous EGFR and ALK tyrosine kinase inhibitors (TKIs) with demonstrated efficacy in patients with EGFR-mutant and ALK-rearranged NSCLCs have been developed, culminating in the availability of the highly effective third-generation TKIs osimertinib and lorlatinib, respectively. Despite their marked efficacy, resistance to these agents remains an unsolved fundamental challenge. Both 'on-target' mechanisms (largely mediated by acquired resistance mutations in the kinase domains of EGFR or ALK) and 'off-target' mechanisms of resistance (mediated by non-target kinase alterations such as bypass signalling activation or phenotypic transformation) have been identified in patients with disease progression on osimertinib or lorlatinib. A growing understanding of the biology and spectrum of these mechanisms of resistance has already begun to inform the development of more effective therapeutic strategies. In this Review, we discuss the development of third-generation EGFR and ALK inhibitors, predominant mechanisms of resistance, and approaches to tackling resistance in the clinic, ranging from novel fourth-generation TKIs to combination regimens and other investigational therapies.

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.

Different roles of the insulin-like growth factor (IGF) axis in non-small cell lung cancer

Abstract:

Non-small cell lung cancer (NSCLC) remains one of the deadliest malignant diseases, with high incidence and mortality worldwide. The insulin-like growth factor (IGF) axis, consisting of IGF-1, IGF-2, related receptors (IGF-1R, -2R), and high-affinity binding proteins (IGFBP 1–6), is associated with promoting fetal development, tissue growth, and metabolism. Emerging studies have also identified the role of the IGF axis in NSCLC, including cancer growth, invasion, and metastasis. Upregulation of IGE-1 and IGF-2, overexpression of IGF-1R, and dysregulation of downstream signaling molecules involved in the PI-3K/Akt and MAPK pathways jointly increase the risk of cancer growth and migration in NSCLC. At the genetic level, some noncoding RNAs could influence the proliferation and differentiation of tumor cells through the IGF signaling pathway. The resistance to some promising drugs might be partially attributed to the IGF axis. Therapeutic strategies targeting the IGF axis have been evaluated, and some have shown promising efficacy. In this review, we summarize the biological roles of the IGF axis in NSCLC, including the expression and prognostic significance of the related components, noncoding RNA regulation, involvement in drug resistance, and therapeutic application. This review offers comprehensive understanding of NSCLC and provides insightful ideas for future research.

Holistic View of ALK TKI Resistance in ALK-Positive Anaplastic Large Cell Lymphoma

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase expressed at early stages of normal development and in various cancers including ALK-positive anaplastic large cell lymphoma (ALK+ ALCL), in which it is the main therapeutic target. ALK tyrosine kinase inhibitors (ALK TKIs) have greatly improved the prognosis of ALK+ALCL patients, but the emergence of drug resistance is inevitable and limits the applicability of these drugs. Although various mechanisms of resistance have been elucidated, the problem persists and there have been relatively few relevant clinical studies. This review describes research progress on ALK+ ALCL including the application and development of new therapies, especially in relation to drug resistance. We also propose potential treatment strategies based on current knowledge to inform the design of future clinical trials.

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.

A Phase 0 Trial of Ceritinib in Patients with Brain Metastases and Recurrent Glioblastoma

PURPOSE

Ceritinib is an orally bioavailable, small-molecule inhibitor of anaplastic lympoma kinase (ALK), insulin-like growth factor 1 receptor (IGFR1), and focal adhesion kinase (FAK), which are highly expressed in glioblastoma and many brain metastases. Preclinical and clinical studies indicate that ceritinib has antitumor activity in central nervous system (CNS) malignancies. This phase 0 trial measured the tumor pharmacokinetics (PK) and pharmacodynamics (PD) of ceritinib in patients with brain metastasis or recurrent glioblastoma.

PATIENTS AND METHODS

Preoperative patients with brain tumors demonstrating high expression of pSTAT5b/pFAK/pIGFR1 were administered ceritinib for 10 days prior to tumor resection. Plasma, tumor, and cerebrospinal fluid (CSF) samples were collected at predefined timepoints following the final dose. Total and unbound drug concentrations were determined using LC-MS/MS. In treated tumor and matched archival tissues, tumor PD was quantified through IHC analysis of pALK, pSTAT5b, pFAK, pIGFR1, and pIRS1.

RESULTS

Ten patients (3 brain metastasis, 7 glioblastoma) were enrolled and no dose-limiting toxicities were observed. Ceritinib was highly bound to human plasma protein [median fraction unbound (Fu), 1.4%] and to brain tumor tissue (median Fu, 0.051% and 0.045% in gadolinium-enhancing and -nonenhancing regions respectively). Median unbound concentrations in enhancing and nonenhancing tumor were 0.048 and 0.006 μmol/L, respectively. Median unbound tumor-to-plasma ratios were 2.86 and 0.33 in enhancing and nonenhancing tumor, respectively. No changes in PD biomarkers were observed in the treated tumor samples as compared to matched archival tumor tissue.

CONCLUSIONS

Ceritinib is highly bound to plasma proteins and tumor tissues. Unbound drug concentrations achieved in brain metastases and patients with recurrent glioblastoma were insufficient for target modulation.

Alteration of ribosome function upon 5-fluorouracil treatment favors cancer cell drug-tolerance

Mechanisms of drug-tolerance remain poorly understood and have been linked to genomic but also to non-genomic processes. 5-fluorouracil (5-FU), the most widely used chemotherapy in oncology is associated with resistance. While prescribed as an inhibitor of DNA replication, 5-FU alters all RNA pathways. Here, we show that 5-FU treatment leads to the production of fluorinated ribosomes exhibiting altered translational activities. 5-FU is incorporated into ribosomal RNAs of mature ribosomes in cancer cell lines, colorectal xenografts, and human tumors. Fluorinated ribosomes appear to be functional, yet, they display a selective translational activity towards mRNAs depending on the nature of their 5'-untranslated region. As a result, we find that sustained translation of IGF-1R mRNA, which encodes one of the most potent cell survival effectors, promotes the survival of 5-FU-treated colorectal cancer cells. Altogether, our results demonstrate that "man-made" fluorinated ribosomes favor the drug-tolerant cellular phenotype by promoting translation of survival genes.

Experimental Determination of Cancer Drug Targets with Independent Mechanisms of Resistance

Mathematical modelling of tumour mutation dynamics has suggested that cancer drug targets that have different resistance mechanisms should be good candidates for combination treatment. This is because the development of mutations that cause resistance to all drugs at once should arise relatively infrequently. However, it is difficult to identify drug targets fulfilling this requirement for particular cancers. Here we present four experimental criteria that we argue are necessary (but not sufficient) conditions that drug combinations should meet in order to be considered for combination drug treatment aimed at delaying or overcoming cancer drug resistance. We present the results of our own experiments - guided by these criteria - using anaplastic lymphoma kinase mutated lung cancer cells. Each set of experiments demonstrate results for different drug combinations. We conclude that the combination of ALK and MEK inhibitors come closest to meeting all our criteria.

Therapeutic advances in non-small cell lung cancer: Focus on clinical development of targeted therapy and immunotherapy

Lung cancer still contributes to nearly one-quarter cancer-related deaths in the past decades, despite the rapid development of targeted therapy and immunotherapy in non-small cell lung cancer (NSCLC). The development and availability of comprehensive genomic profiling make the classification of NSCLC more precise and personalized. Most treatment decisions of advanced-stage NSCLC have been made based on the genetic features and PD-L1 expression of patients. For the past 2 years, more than 10 therapeutic strategies have been approved as first-line treatment for certain subgroups of NSCLC. However, some major challenges remain, including drug resistance and low rate of overall survival. Therefore, we discuss and review the therapeutic strategies of NSCLC, and focus on the development of targeted therapy and immunotherapy in advanced-stage NSCLC. Based on the latest guidelines, we provide an updated summary on the standard treatment for NSCLC. At last, we discussed several potential therapies for NSCLC. The development of new drugs and combination therapies both provide promising therapeutic effects on NSCLC.

Guidelines for clinical practice of ALK fusion detection in non-small-cell lung cancer: a proposal from the Chinese RATICAL study group

The presence of anaplastic lymphoma kinase (ALK) rearrangement defines a molecular subtype of non-small cell lung cancer (NSCLC). ALK inhibitors (ALKIs) confer significant clinical benefits in patients with ALK-positive advanced NSCLC; therefore, it is of great clinical significance to select accurate, rapid, and appropriate ALK testing methods to screen for patients who are suitable for anti-ALK treatment. In recent years, great progress has been made in the development and clinical application of ALKIs, as well as in our understanding of acquired drug resistance mechanisms. Meanwhile, new ALK companion diagnostic platforms have been developed and applied in clinical practice. Although many studies have shown that there is a high rate of concordance among these platforms, new problems continue to appear during testing. To maximize the benefit for patients, accurate testing results can be obtained by first selecting the appropriate testing method and then formulating, optimizing, and complying with the standardized testing process in accordance with the testing population and specimen types. With the ongoing accumulation of clinical practice data, experience from quality control of ALK testing, and results from multicenter research, an updated expert consensus is necessary. The experts who participated in the discussion and development of this guideline have a rich background in theoretical and clinical testing experience, which ensures the practical value of the information presented in this guideline.

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.

The Resistance Mechanisms and Treatment Strategies for ALK-Rearranged Non-Small Cell Lung Cancer

Anaplastic lymphoma kinase (ALK) is a validated molecular target for non-small-cell lung cancer (NSCLC). The use of tyrosine kinase inhibitors (TKIs) has led to significantly improved survival benefits. However, the clinical benefits of targeting ALK using TKIs are limited due to the emergence of drug resistance. The landscape of resistance mechanisms and treatment decisions has become increasingly complex. Therefore, continued research into new drugs and combinatorial therapies is required to improve outcomes in NSCLC. In this review, we explore the resistance mechanisms of ALK TKIs in advanced NSCLC in order to provide a theoretical basis and research ideas for solving the problem of ALK drug resistance.

Polyclonal on- and off-target resistance mutations in an EML4-ALK positive non-small cell lung cancer patient under ALK inhibition

Treatment of advanced stage anaplastic lymphoma kinase (ALK) positive non-small cell lung cancer (NSCLC) with ALK tyrosine kinase inhibitors (TKIs) has been shown to be superior to standard platinum-based chemotherapy. However, secondary progress of disease frequently occurs under ALK inhibitor treatment. The clinical impact of re-biopsies for treatment decisions beyond secondary progress is, however, still under debate. Here, we report on two novel subsequent polyclonal on- and off-target resistance mutations in a patient with ALK-fused NSCLC under ALK inhibitor treatment. A 63-year-old male patient with an advanced stage EML4-ALK fused pulmonary adenocarcinoma was initially successfully treated with the second-generation ALK inhibitor alectinib and upon progressions subsequently with brigatinib, lorlatinib and chemoimmunotherapy (CIT). Progress to alectinib was associated with a so far undescribed ALK mutation (p.A1200_G1201delinsW) which was, however, tractable by brigatinib. An off-target KRAS-mutation (p.Q61K) occurred in association with subsequent progression under second-line TKI treatment. Third-line lorlatinib showed limited efficacy but chemoimmunotherapy resulted in disappearance of the KRAS mutant clone and clinical tumor control for another eight months. In conclusion, we suggest molecular profiling of progressive tumor disease also for ALK-positive NSCLC to personalize treatment in a subgroup of ALK-positive patients.

Exceptional response to the ALK and ROS1 inhibitor lorlatinib and subsequent mechanism of resistance in relapsed ALK F1174L-mutated neuroblastoma

Treatment of high-risk neuroblastoma typically incorporates multiagent chemotherapy, surgery, radiation therapy, autologous stem cell transplantation, immunotherapy, and differentiation therapy. The discovery of activating mutations in ALK receptor tyrosine kinase (ALK) in ∼8% of neuroblastomas opens the possibility of further improving outcomes for this subset of patients with the addition of ALK inhibitors. ALK inhibitors have shown efficacy in tumors such as non-small-cell lung cancer and anaplastic large cell lymphoma in which wild-type ALK overexpression is driven by translocation events. In contrast, ALK mutations driving neuroblastomas are missense mutations in the tyrosine kinase domain yielding constitutive activation and differing sensitivity to available ALK inhibitors. We describe a case of a patient with relapsed, refractory, metastatic ALK F1174L-mutated neuroblastoma who showed no response to the first-generation ALK inhibitor crizotinib but had a subsequent complete response to the ALK/ROS1 inhibitor lorlatinib. The patient's disease relapsed after 13 mo of treatment. Sequencing of cell-free DNA at the time of relapse pointed toward a potential mechanism of acquired lorlatinib resistance: amplification of CDK4 and FGFR1 and a NRAS Q61K mutation. We review the literature regarding differing sensitivity of ALK mutations found in neuroblastoma to current FDA-approved ALK inhibitors and known pathways of acquired resistance. Our report adds to the literature of important correlations between neuroblastoma ALK mutation status and clinical responsiveness to ALK inhibitors. It also highlights the importance of understanding acquired mechanisms of resistance.

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.

The role of molecular heterogeneity targeting resistance mechanisms to lung cancer therapies

Introduction: The treatment scenario of lung cancer is rapidly evolving through time. In parallel, growing evidence is accumulating on different mechanisms of treatment resistance. Inter- and intra-tumor heterogeneity define the spatial and temporal tumor clonal evolution, that is at the basis of tumor progression and resistance to anticancer treatments.Areas covered: This review summarizes the available evidence on molecular heterogeneity in lung cancer, from diagnosis to the occurrence of treatment resistance. The application of novel molecular diagnostic methods to detect molecular heterogeneity, and the implications of understanding heterogeneity for drug development strategies are discussed, with focus on clinical relevance and impact on patients' survival.Expert opinion: The current knowledge of molecular heterogeneity allows to identify different molecular subgroups of patients within the same conventional tumor type. Deeper understanding of heterogeneity determinants and the possibility to comprehensively investigate tumor molecular patterns will lead to the development of personalized treatment approaches, with the final goal to overcome resistance and prolong survival in lung cancer patients.