Ubiquitin ligase Cbl-b is involved in icotinib (BPI-2009H)-induced apoptosis and G1 phase arrest of EGFR mutation-positive non-small-cell lung cancer

Chitinase 3-like-1 (CHI3L1) in the pathogenesis of epidermal growth factor receptor mutant non-small cell lung cancer

Non-small cell lung cancer (NSCLC) accounts for 85 % of all lung cancers. In NSCLC, 10-20 % of Caucasian patients and 30-50 % of Asian patients have tumors with activating mutations in the Epidermal Growth Factor Receptor (EGFR). A high percentage of these patients exhibit favorable responses to treatment with tyrosine kinase inhibitors (TKI). Unfortunately, a majority of these patients develop therapeutic resistance with progression free survival lasting 9-18 months. The mechanisms that underlie the tumorigenic effects of EGFR and the ability of NSCLC to develop resistance to TKI therapies, however, are poorly understood. Here we demonstrate that CHI3L1 is produced by EGFR activation of normal epithelial cells, transformed epithelial cells with wild type EGFR and cells with cancer-associated, activating EGFR mutations. We also demonstrate that CHI3L1 auto-induces itself and feeds back to stimulate EGFR and its ligands via a STAT3-dependent mechanism(s). Highly specific antibodies against CHI3L1 (anti-CHI3L1/FRG) and TKI, individually and in combination, abrogated the effects of EGFR activation on CHI3L1 and the ability of CHI3L1 to stimulate the EGFR axis. Anti-CHI3L1 also interacted with osimertinib to reverse TKI therapeutic resistance and induce tumor cell death and inhibit pulmonary metastasis while stimulating tumor suppressor genes including KEAP1. CHI3L1 is a downstream target of EGFR that feeds back to stimulate and activate the EGFR axis. Anti-CHI3L1 is an exciting potential therapeutic for EGFR mutant NSCLC, alone and in combination with osimertinib or other TKIs.

The role of CBL family ubiquitin ligases in cancer progression and therapeutic strategies

The CBL (Casitas B-lineage lymphoma) family, as a class of ubiquitin ligases, can regulate signal transduction and activate receptor tyrosine kinases through various tyrosine kinase-dependent pathways. There are three members of the family: c-CBL, CBL-b, and CBL-c. Numerous studies have demonstrated the important role of CBL in various cellular pathways, particularly those involved in the occurrence and progression of cancer, hematopoietic development, and regulation of T cell receptors. Therefore, the purpose of this review is to comprehensively summarize the function and regulatory role of CBL family proteins in different human tumors, as well as the progress of drug research targeting CBL family, so as to provide a broader clinical measurement strategy for the treatment of tumors.

Novel anilino quinazoline-based EGFR tyrosine kinase inhibitors for treatment of non-small cell lung cancer

The epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of non-small cell lung cancer (NSCLC). EGFR-TKI positron emission tomography (PET) probes based on the central quinazoline core show great potential for NSCLC diagnosis, and pre-clinical and clinical therapy monitoring. In our previous research, anilino quinazoline based PET probe, N-(3-chloro-4-fluorophenyl)-7-(2-(2-(2-(2-¹⁸F-fluoroethoxy) ethoxy) ethoxy) ethoxy)-6-methoxyquinazolin-4-amine (¹⁸F-MPG), have been developed, and it has been successfully demonstrated to be a powerful non-invasive imaging tool for differentiating EGFR mutation status and stratifying NSCLC patients for EGFR-TKI treatment in a clinical study (n = 75 patients). Moreover, it has been found that ¹⁸F-MPG shows excellent tumor targeting performance and good pharmacokinetic characteristics in NSCLC patients. These results motivate us to investigate the cancer treatment efficacy of non-radioactive F-MPG and its analogue N-(3-chloro-4-fluorophenyl)-7-(2-(2-(2-(2-hydroxyethoxy)ethoxy) ethoxy) ethoxy)-6-methoxyquinazolin-4-amine (OH-MPG) in vitro and in small animal models. Our studies revealed that both F-MPG and OH-MPG displayed high therapeutic effect to NSCLC cells (IC₅₀ = 5.3 nM and 2.0 nM to HCC827 cells for F-MPG and OH-MPG, respectively). More importantly, compared with a standard EGFR-TKI, 4-(3-bromoanilino)-6,7-dimethoxyquinazoline (PD153035), F-MPG and OH-MPG showed stronger tumor inhibition in preclinical models. Furthermore, the treatment efficacy of F-MPG or OH-MPG monitored by ¹⁸F-FDG-PET indicated that tumor uptake in treated groups was significantly decreased. Ex vivo experiments showed that the levels of serum biomarkers and pathological changes in the liver were significantly reduced in the F-MPG and OH-MPG group, compared to PD153035 treated group. In conclusion, EGFR targeted F-MPG and OH-MPG exhibit promising anti-tumor activity with limited liver damage, thus representing promising drug candidates for further investigation for combating the deadly NSCLC.

Suppressed expression of Cbl-b by NF-κB mediates icotinib resistance in EGFR-mutant non-small-cell lung cancer

Although epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) could greatly improve the prognosis of NSCLC patients harboring activating EGFR mutations, drug resistance still remains a major obstacle to successful treatment. Our previous study found that the EGFR-TKI icotinib could upregulate the expression of Casitas-B-lineage lymphoma protein-B (Cbl-b), an E3 ubiquitin ligase. In the present study, we aimed to clarify the potential role of Cbl-b in the resistance to icotinib, and the underlying mechanisms using EGFR-mutant cell lines. We found that icotinib inhibited the proliferation of mutant-EGFR NSCLC cells (PC9 and HCC827), and upregulated the expression of Cbl-b at both the protein and mRNA levels. Cbl-b knockdown decreased the sensitivity of PC9 and HCC827 cells to icotinib, and partially restored icotinib-inhibited AKT activation in PC9 cells. On the contrary, Cbl-b overexpression could partly reverse the drug resistance in PC9 icotinib-resistant cells (PC9/IcoR). Moreover, overexpressing p65, the main member of transcription factor NF-κB family, reversed the icotinib-mediated upregulation of Cbl-b. Collectively, these data suggest that icotinib could upregulate Cbl-b mediated by NF-κB inhibition, and Cbl-b contribute to the icotinib sensitivity in EGFR-mutant NSCLC cells. This study highlights that low expression of Cbl-b might be the key obstacles in the efficacy of icotinib therapy.

Epidermal Growth Factor Receptor Gene in Non-Small-Cell Lung Cancer: The Importance of Promoter Polymorphism Investigation

Recently, epidermal growth factor receptor (EGFR) was a key molecule in investigation of lung cancer, and it was a target for a new therapeutic strategy, based on molecular analyses. In this review, we have summarized some issues considering the role of EGFR in lung cancer, its coding gene, and its promoter gene polymorphisms (SNPs) -216G/T and -191C/A in non-small-cell lung cancer (NSCLC). The position of the SNPs indicates their significant role in EGFR regulation. The accumulation of knowledge regarding SNPs lately suggests their significant and important role in the onset of carcinogenesis, the prediction of the onset of metastases, the response to therapy with TKI inhibitors, and the onset of toxic effects of the applied therapy. Based on this, we suggest further studies of the relationship of clinical significance to SNPs in patients with lung tumors.

Efficacy and safety of icotinib in treating non-small cell lung cancer: a systematic evaluation and meta-analysis based on 15 studies

Icotinib is a new epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) that developed and used in China; this work was to evaluate its efficacy and safety in treating non-small cell lung cancer (NSCLC). Clinical studies evaluating the efficacy and safety of icotinib in treating NSCLC were identified from the databases of Medline, Web of Science, Embase and Cochrance Library. Pooled efficacy and safety of icotinib were calculated through a series of predefined search strategies. A total of 15 studies with 2,304 patients were involved in this study. The overall response rate (ORR) and disease control rate (DCR) of icotinib were 40.99% (95% CI: 33.77% to 48.22%) and 77.16% (95% CI: 51.43% to 82.31%). The pooled progression-free survival (PFS) and overall survival (OS) were 7.34 months (95% CI: 5.60 to 9.07) and 14.98 months (95% CI: 9.78 to 20.18). Patients with EGFR mutations exhibited better ORR (OR = 3.67, p < 0.001), DCR (OR = 1.39, p = 0.001) and PFS (11.0 ± 0.76 vs. 1.97 ± 0.82 months). Moreover, patients with rash had a higher ORR (OR = 2.14, p = 0.001) than those without rash. The common adverse effects (AEs) included skin rash (31.4%), diarrhea (14.2%), pruritus (6.7%) and hepatic toxicity (3.8%) and most of them were well tolerated. In conclusion, Icotinib is an effective and well tolerated regimen for Chinese patients with advanced NSCLC. Further randomized trials with large population are required to provide stronger evidence for icotinib in treating NSCLC.

Construction of a 26‑feature gene support vector machine classifier for smoking and non‑smoking lung adenocarcinoma sample classification

The present study aimed to identify the feature genes associated with smoking in lung adenocarcinoma (LAC) samples and explore the underlying mechanism. Three gene expression datasets of LAC samples were downloaded from the Gene Expression Omnibus database through pre-set criteria and the expression data were processed using meta-analysis. Differentially expressed genes (DEGs) between LAC samples of smokers and non-smokers were identified using limma package in R. The classification accuracy of selected DEGs were visualized using hierarchical clustering analysis in R language. A protein-protein interaction (PPI) network was constructed using gene interaction data from the Human Protein Reference Database for the DEGs. Betweenness centrality was calculated for each node in the network and genes with the greatest BC values were utilized for the construction of the support vector machine (SVM) classifier. The dataset GSE43458 was used as the training dataset for the construction and the other datasets (GSE12667 and GSE10072) were used as the validation datasets. The classification accuracy of the classifier was tested using sensitivity, specificity, positive predictive value, negative predictive value and area under curve parameters with the pROC package in R language. The feature genes in the SVM classifier were subjected to pathway enrichment analysis using Fisher's exact test. A total of 347 genes were identified to be differentially expressed between samples of smokers and non-smokers. The PPI network of DEGs were comprised of 202 nodes and 300 edges. An SVM classifier comprised of 26 feature genes was constructed to distinguish between different LAC samples, with prediction accuracies for the GSE43458, GSE12667 and GSE10072 datasets of 100, 100 and 94.83%, respectively. Furthermore, the 26 feature genes that were significantly enriched in 9 overrepresented biological pathways, including extracellular matrix-receptor interaction, proteoglycans in cancer, cell adhesion molecules, p53 signaling pathway, microRNAs in cancer and apoptosis, were identified to be smoking-related genes in LAC. In conclusion, an SVM classifier with a high prediction accuracy for smoking and non-smoking samples was obtained. The genes in the classifier may likely be the potential feature genes associated with the development of patients with LAC who smoke.

H19 non coding RNA-derived miR-675 enhances tumorigenesis and metastasis of breast cancer cells by downregulating c-Cbl and Cbl-b

H19 is a long non-coding RNA precursor of miR-675microRNA. H19 is increasingly described to play key roles in the progression and metastasis of cancers from different tissue origins. We have previously shown that the H19 gene is activated by growth factors and increases breast cancer cell invasion. In this study, we established H19/miR-675 ectopic expression models of MDA-MB-231 breast cancer cells to further investigate the underlying mechanisms of H19 oncogenic action. We showed that overexpression of H19/miR-675 enhanced the aggressive phenotype of breast cancer cells including increased cell proliferation and migration in vitro, and increased tumor growth and metastasis in vivo. Moreover, we identified ubiquitin ligase E3 family (c-Cbl and Cbl-b) as direct targets of miR-675 in breast cancer cells. Using a luciferase assay, we demonstrated that H19, through its microRNA, decreased both c-Cbl and Cbl-b expression in all breast cancer cell lines tested. Thus, by directly binding c-Cbl and Cbl-b mRNA, miR-675 increased the stability and the activation of EGFR and c-Met, leading to sustained activation of Akt and Erk as well as enhanced cell proliferation and migration. Our data describe a novel mechanism of protumoral action of H19 in breast cancer.

Zoledronic acid increases the antitumor effect of gefitinib treatment for non-small cell lung cancer with EGFR mutations

Non-small cell lung cancer (NSCLC) patients with epithelial growth factor receptor (EGFR) mutations and bone metastases are often concurrently administered tyrosine kinase inhibitors (TKIs) and bisphosphonates. Yet, the effects and mechanisms of these agents are unclear. In the present study, we aimed to ascertain whether zoledronic acid (ZA) increases the antitumor effects of gefitinib treatment on NSCLC with EGFR mutations and the related mechanisms of action. The effects of ZA and gefitinib on NSCLC tumor cells with EGFR mutations (HCC827, HCC827 GR and H1975) in regards to proliferation, apoptosis, cell cycle and signaling pathways were detected. ZA increased the antitumor effects of gefitinib on NSCLC with EGFR activating mutations and TKI resistance in vitro. Gefitinib caused cell cycle arrest in the G0/G1 phase, ZA induced S phase accumulation and the effect of the combined treatment was neutralization. Combined treatment obviously inhibited STAT3 and/or p‑STAT3 protein expression compared with treatment with each single drug in vitro and in vivo, and it also significantly inhibited TKI resistance NSCLC tumor growth in vivo. In conclusion, ZA increased the antitumor effects of gefitinib on NSCLC with EGFR activating mutations and TKI resistance by regulating the cell cycle, inducing caspase-3 expression and inhibiting STAT3 expression.

Development of population pharmacokinetics model of icotinib with non-linear absorption characters in healthy Chinese volunteers to assess the CYP2C19 polymorphism and food-intake effect

PURPOSE

Icotinib is a potent and selective inhibitor of epidermal growth factor receptors (EGFR) approved to treat non-small cell lung cancer (NSCLC). However, its high variability may impede its application. The objectives of this analysis were to assess plasma pharmacokinetics and identify covariates that may explain variability in icotinib absorption and/or disposition following single dose of icotinib in healthy volunteers.

METHODS

Data from two clinical studies (n = 22) were analyzed. One study was designed as three-period and Latin-squared (six sequence) trial to evaluate dose proportionality, and the other one was designed as two-way crossover trial to evaluate food effect on pharmacokinetics (PK) characters. Icotinib concentrations in plasma were analyzed using non-linear mixed-effects model (NONMEM) method. The model was used to assess influence of food, demographic characteristics, measurements of blood biochemistry, and CYP2C19 genotype on PK characters of icotinib in humans. The final model was diagnosed by goodness-of-fit plots and evaluated by visual predictive check (VPC) and bootstrap methods.

RESULTS

A two-compartment model with saturated absorption character was developed to capture icotinib pharmacokinetics. Typical value of clearance, distribution clearance, central volume of distribution, maximum absorption rate were 29.5 L/h, 24.9 L/h, 18.5 L, 122.2 L and 204,245 μg/h, respectively. When icotinib was administrated with food, bioavailability was estimated to be increased by 48%. Inter-occasion variability was identified to affect on maximum absorption rate constant in food-effect study. CL was identified to be significantly influenced by age, albumin concentration (ALB), and CYP2C19 genotype. No obvious bias was found by VPC and bootstrap methods.

CONCLUSIONS

The developed model can capture icotinib pharmacokinetics well in healthy volunteers. Food intake can increase icotinib exposure. Three covariates, age, albumin concentration, and CYP2C19 genotype, were identified to significantly affect icotinib PK profiles in healthy subjects.

Icotinib, a selective EGF receptor tyrosine kinase inhibitor, for the treatment of non-small-cell lung cancer

ABSTRACT 

Advanced non-small-cell lung cancer (NSCLC) is the main cause for cancer-related mortality. Treatments for advanced NSCLC are largely palliative and a benefit plateau appears to have reached with the platinum-based chemotherapy regimens. EGF receptor (EGFR) tyrosine kinase inhibitors gefitinib, erlotinib and afatinib came up with prolonged progression-free survival and improved quality of life, especially in EGFR-mutated patients. Icotinib is an oral selective EGFR tyrosine kinase, which was approved by China Food and Drug administration in June 2011 for treating advanced NSCLC. Its approval was based on the registered Phase III trial (ICOGEN), which showed icotinib is noninferior to gefitinib. This review will discuss the role of icotinib in NSCLC, and its potential application and ongoing investigations.

Icotinib inhibits the invasion of Tca8113 cells via downregulation of nuclear factor κB-mediated matrix metalloproteinase expression

Icotinib is an epidermal growth factor receptor tyrosine kinase inhibitor, which has been revealed to inhibit proliferation in tumor cells. However, the effect of icotinib on cancer cell metastasis remains to be explained. This study examines the effect of icotinib on the migration and invasion of squamous cells of tongue carcinoma (Tca8113 cells) in vitro. The results of the Boyden chamber invasion assay demonstrated that icotinib reduced cell invasion, suppressed the protein levels of matrix metalloproteinases (MMPs), MMP-2 and MMP-9, and increased the expression of tissue inhibitor of metalloproteinase-1. In addition, icotinib was found to significantly decrease the protein levels of nuclear factor κB (NF-κB) p65, which suggested that icotinib inhibits NF-κB activity. Furthermore, treatment with the NF-κB inhibitor, pyrrolidine dithiocarbamate, suppressed cell invasion and MMP-2 expression. These results suggested that icotinib inhibits the invasion of Tca8113 cells by downregulating MMP via the inactivation of the NF-κB signaling pathways.

Icotinib: activity and clinical application in Chinese patients with lung cancer

INTRODUCTION

Icotinib (BPI-2009H, Conmana) is a novel oral quinazoline compound that has proven survival benefit in Chinese patients with lung cancer, for which several therapies are currently available often with unsatisfactory results. Icotinib is the first self-developed small molecular drug in China for targeted therapy of lung cancer.

AREAS COVERED

The authors' experience in the clinical application of icotinib is reviewed in combination with related publications in the literature. Antitumor activities were observed in non-small-cell lung cancer and others in several recent studies. On 7 June 2011, icotinib was approved by the State Food and Drug Administration of China for the treatment of local advanced or metastatic non-small-cell lung cancer based on the results of a nationwide, of 27 centers, randomized, double-blind, double-modulated, parallel-controlled, Phase III trial with single agent icotinib in lung cancer patients after failure of chemotherapy.

EXPERT OPINION

Icotinib is a generic drug. Compared to the other two commercially available EGFR tyrosine kinase inhibitors, gefitinib and erlotinib, icotinib is similar to them in chemical structure, mechanism of activity and therapeutic effects but less expensive. Better safety as well as a wider therapeutic window has also been proven in several Chinese studies. Future studies on cost effectiveness are warranted.