Non-small-cell lung cancer harbouring mutations in the EGFR kinase domain

Targeting exon mutations in NSCLC: clinical insights into LAG-3, TIM-3 pathways, and advances in fourth-generation EGFR-TKIs

Lung cancer remains the second leading cause of cancer-related morbidity and mortality worldwide, with non-small cell lung cancer (NSCLC) accounting for the majority of cases. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have become the standard first-line therapy for advanced NSCLC with EGFR mutations, offering significant improvements in progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) compared to chemotherapy alone. Recent studies suggest that their effectiveness decreased with the emergence of acquired resistance, such as C797S and T790M. Immunotherapy alone also shows enhanced PFS and OS over chemotherapy; however, its applicability can be limited in cases with low programmed cell death ligand 1 (PD-L1) expression and result in immune-related adverse effects like those observed in retrospective, non-randomized studies. Emerging fourth-generation EGFR-TKIs, currently under clinical trials, show promising potential to address these resistance mechanisms. Advanced inhibitors, including BBT-176, BLU-945, and BLU-701, have effectively targeted resistant mutations and reduced disease progression. Studies have suggested that combining fourth-generation EGFR-TKIs with immunotherapies targeting novel pathways like LAG-3 and TIM-3 may enhance patient outcomes. Such combination regimens aim to optimize PFS, OS, and ORR while minimizing adverse effects and addressing the limitations of current therapies. This study explores the landscape of EGFR mutations, their clinical significance, and the integration of innovative fourth-generation EGFR-TKIs with immunotherapies, emphasizing the potential of precision medicine in advancing the management of EGFR-mutated NSCLC.

Discovery and preclinical evaluations of drug candidate DA-0157 capable of overcoming EGFR drug-resistant mutation C797S and EGFR/ALK co-mutations

Activating mutations in the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) are significant oncogenic drivers in non-small cell lung cancer (NSCLC) patients. Despite several approved EGFR and ALK inhibitors, drug-resistant mutations pose a major challenge. Especially, there is currently no approved EGFR inhibitors targeting the C797S mutation, a refractory mutation resistant to the third-generation EGFR inhibitors. Furthermore, an increasing number of patients with EGFR/ALK co-mutations have been identified in clinical practice, yet there are no effective therapeutic options available for them. In this study, we report the discovery and preclinical evaluations of a new small-molecule drug candidate, DA-0157, which is capable of overcoming EGFR drug-resistant mutation C797S and EGFR/ALK co-mutations. DA-0157 demonstrated excellent in vitro efficacy, significantly inhibiting various EGFRC797S mutants resistant to the third-generation EGFR inhibitors, ALK rearrangements, and EGFR/ALK co-mutations. In vivo studies revealed that DA-0157 substantially inhibited tumor growth in the LD1-0025-200717 EGFRDel19/T790M/C797S PDX model (40 mg/kg/d, TGI: 98.3 %), Ba/F3-EML-4-ALK-L1196 M CDX model (40 mg/kg/d, TGI: 125.2 %), and NCI-H1975 EGFRDel19/T790M/C797S & NCI-H3122 (EML4-ALK) dual-side implantation CDX model (40 mg/kg/d, TGI: 89.5 % & 113.9 %). DA-0157 demonstrates favorable pharmacokinetic properties and safety. Currently, DA-0157 (DAJH-1050766) is undergoing Phase I/II clinical trials.

Identification of novel inhibitors for epidermal growth factor receptor tyrosine kinase using absolute binding free-energy simulations

Mutations in the kinase domain of the epidermal growth factor receptor (EGFR), a critical biological macromolecule involved in cell growth and division, can lead to drug resistance in patients undergoing chemotherapy with kinase inhibitors. Notably, the emergence of the C797S mutation poses new challenges for targeted EGFR therapy, highlighting the urgent need for agents effective against this triple mutation (L858R/T790M/C797S, EGFR™). Building on our previous finding that sulfonyl and piperidinyl groups significantly contribute to the EGFR™-inhibitor interactions, we have identified the best-in-class inhibitors containing these groups through functional-group-based screening and formally exact absolute binding free-energy calculations. Our new strategy offers greater flexibility than traditional workflows leaning on relative binding free-energy calculations and accommodates ligands with substantial structural variations. The result shows that the top candidate exhibits a binding affinity of -15.8 kcal/mol towards the EGFR™ mutant, surpassing BLU-945, a state-of-the-art fourth-generation inhibitor with a binding free energy of -12.6 kcal/mol. Subsequent free-energy decomposition indicates that the presented top candidate primarily enhances interactions with the K745, D800 and R841 residues, suggesting its potential to overcome resistance from the C797S mutation. Notably, K745 forms highly favorable hydrogen bonds and cation-π interactions with C6. Targeting lysine has emerged as a promising strategy, especially in cases where the C797S mutation renders traditional covalent inhibitors ineffective. We propose that these novel inhibitors represent promising drug candidates for non-small cell lung cancer treatment and offer new strategies to overcome drug resistance caused by EGFR mutation.

The use of hyaluronic acid in a 3D biomimetic scaffold supports spheroid formation and the culture of cancer stem cells

Three-dimensional (3D) bioprinting culture models capable of reproducing the pathological architecture of diseases are increasingly advancing. In this study, 3D scaffolds were created using extrusion-based bioprinting method with alginate, gelatin, and hyaluronic acid to investigate the effects of hyaluronic acid on the physical properties of the bioscaffold as well as on the formation of liver cancer spheroids. Conformational analysis, rheological characterization, and swelling-degradation tests were performed to characterize the scaffolds. After generating spheroids from hepatocellular carcinoma cells on the 3D scaffolds, cell viability and proliferation assays were performed. Flow cytometry and immunofluorescence microscopy were used into examine the expression of albumin, CD44, and E-cadherin to demonstrate functional capability and maturation levels of the spheroid-forming cells. The results show that hyaluronic acid in the scaffolds correlates with spheroid formation and provides high survival rates. It is also associated with an increase in CD44 expression and a decrease in E-cadherin, while there is no significant change in the albumin expression in the cells. Overall, the findings demonstrate that hyaluronic acid in a 3D hydrogel scaffold supports spheroid formation and may induce stemness. We present a promising 3D scaffold model for enhancing liver cancer spheroid formation and mimicking solid tumors. This model also has the potential for further studies to examine stem cell properties in 3D models.

Binding Thermodynamics of Fourth-Generation EGFR Inhibitors Revealed by Absolute Binding Free Energy Calculations

The overexpression or mutation of the kinase domain of the epidermal growth factor receptor (EGFR) is strongly associated with non-small-cell lung cancer (NSCLC). EGFR tyrosine kinase inhibitors (TKIs) have proven to be effective in treating NSCLC patients. However, EGFR mutations can result in drug resistance. To elucidate the mechanisms underlying this resistance and inform future drug development, we examined the binding affinities of BLU-945, a recently reported fourth-generation TKI, to wild-type EGFR (EGFRWT) and its double-mutant (L858R/T790M; EGFRDM) and triple-mutant (L858R/T790M/C797S; EGFRTM) forms. We compared the binding affinities of BLU-945, BLU-945 analogues, CH7233163 (another fourth-generation TKI), and erlotinib (a first-generation TKI) using absolute binding free energy calculations. Our findings reveal that BLU-945 and CH7233163 exhibit binding affinities to both EGFRDM and EGFRTM stronger than those of erlotinib, corroborating experimental data. We identified K745 and T854 as the key residues in the binding of fourth-generation EGFR TKIs. Electrostatic forces were the predominant driving force for the binding of fourth-generation TKIs to EGFR mutants. Furthermore, we discovered that the incorporation of piperidinol and sulfone groups in BLU-945 substantially enhanced its binding capacity to EGFR mutants. Our study offers valuable theoretical insights for optimizing fourth-generation EGFR TKIs.

Discovery of Novel Fourth-Generation EGFR Inhibitors to Overcome C797S-Mediated Resistance

Epidermal growth factor receptor (EGFR)-activating mutation is an important oncogenic driver of nonsmall cell lung cancer (NSCLC) patients. Osimertinib has been the first-line treatment for EGFR-mutated NSCLC. However, the tertiary C797S mutation leads to Osimertinib resistance by blocking the covalent binding of Cys797 to Osimertinib. To date, there are no approved inhibitors for the treatment of Osimertinib resistance. Herein, we identified a novel lead compound S8 targeting EGFRL858R/T790M/C797S by structure-based virtual screening and synthesized a series of novel compounds. Representative compound C34 showed potent inhibitory activity against EGFRL858R/T790M/C797S with an IC50 of 5.1 nM and significantly inhibited the proliferation of the H1975-TM cell line harboring EGFRL858R/T790M/C797S with an IC50 of 0.05 μM. Additionally, compound C34 demonstrated good pharmacokinetic properties with an oral bioavailability of 30.72% and significantly inhibited tumor growth in the H1975-TM xenograft tumor model. This study provides a novel thiazole derivative as an EGFR inhibitor to overcome C797S-mediated resistance.

A fluorogenic probe for predicting treatment response in non-small cell lung cancer with EGFR-activating mutations

Therapeutic responses of non-small cell lung cancer (NSCLC) to epidermal growth factor receptor (EGFR) - tyrosine kinase inhibitors (TKIs) are known to be associated with EGFR mutations. However, a proportion of NSCLCs carrying EGFR mutations still progress on EGFR-TKI underlining the imperfect correlation. Structure-function-based approaches have recently been reported to perform better in retrospectively predicting patient outcomes following EGFR-TKI treatment than exon-based method. Here, we develop a multicolor fluorescence-activated cell sorting (FACS) with an EGFR-TKI-based fluorogenic probe (HX103) to profile active-EGFR in tumors. HX103-based FACS shows an overall agreement with gene mutations of 82.6%, sensitivity of 81.8% and specificity of 83.3% for discriminating EGFR-activating mutations from wild-type in surgical specimens from NSCLC patients. We then translate HX103 to the clinical studies for prediction of EGFR-TKI sensitivity. When integrating computed tomography imaging with HX103-based FACS, we find a high correlation between EGFR-TKI therapy response and probe labeling. These studies demonstrate HX103-based FACS provides a high predictive performance for response to EGFR-TKI, suggesting the potential utility of an EGFR-TKI-based probe in precision medicine trials to stratify NSCLC patients for EGFR-TKI treatment.

Discovery of BLU-945, a Reversible, Potent, and Wild-Type-Sparing Next-Generation EGFR Mutant Inhibitor for Treatment-Resistant Non-Small-Cell Lung Cancer

While epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have changed the treatment landscape for EGFR mutant (L858R and ex19del)-driven non-small-cell lung cancer (NSCLC), most patients will eventually develop resistance to TKIs. In the case of first- and second-generation TKIs, up to 60% of patients will develop an EGFR T790M mutation, while third-generation irreversible TKIs, like osimertinib, lead to C797S as the primary on-target resistance mutation. The development of reversible inhibitors of these resistance mutants is often hampered by poor selectivity against wild-type EGFR, resulting in potentially dose-limiting toxicities and a sub-optimal profile for use in combinations. BLU-945 (compound 30) is a potent, reversible, wild-type-sparing inhibitor of EGFR+/T790M and EGFR+/T790M/C797S resistance mutants that maintains activity against the sensitizing mutations, especially L858R. Pre-clinical efficacy and safety studies supported progression of BLU-945 into clinical studies, and it is currently in phase 1/2 clinical trials for treatment-resistant EGFR-driven NSCLC.

Molecular Targets in Lung Cancer: Study of the Evolution of Biomarkers Associated with Treatment with Tyrosine Kinase Inhibitors—Has NF1 Tumor Suppressor a Key Role in Acquired Resistance?

Simple Summary

Resistance to tyrosine kinase inhibitors in patients with EGFR-mutated non-small cell lung cancer is crucial in the development of the disease. Detecting the mechanisms of this resistance is fundamental in lung cancer research, so we evaluated the presence of EGFR mutations in circulating free DNA in plasma of patients with NSCLC under oncological treatment. We studied the role of EGFR and other driver mutations in their involvement in acquired resistance to treatment with EGFR-TKIs and we analyzed the role of liquid biopsy as a non-invasive diagnostic method. Our results showed that liquid biopsy is a very useful tool monitoring the evolution of the disease and the resistance to TKIs. The detection of other concomitant mutations in driver genes is also key in this regard, so we found that alterations in the NFI tumor suppressor gene could be playing a role in disease progression and resistance to targeted therapies.

Abstract

The application to clinical practice of liquid biopsy in patients with lung cancer has led to an advance in the diagnosis and monitoring of the disease. Detection of alterations in EGFR genes related to TKI treatment in EGFR-mutated non-small cell lung cancer patients is a routine method in pathology laboratories. The primary objective of this work was to analyze the presence of EGFR mutations in cfDNA of 86 patients with lung cancer undergoing oncological treatment related to response to treatment with TKIs. Secondarily, we evaluated the dynamics of EGFR mutations, the presence of the T790M alteration and its relationship with drug resistance and analyzed by NGS molecular alterations in cfDNA of patients with discordant progression. Our results demonstrate that understanding the mutational status of patients treated with TKIs over time is essential to monitor disease progression. In this context, liquid biopsy is a fundamental key. In addition, it is not only necessary to detect EGFR mutations, but also other concomitant mutations that would be influencing the development of the disease. In this sense, we have discovered that mutations in the NF1 tumor suppressor gene could be exerting an as yet unknown function in lung cancer.

Molecular hybrids: A five-year survey on structures of multiple targeted hybrids of protein kinase inhibitors for cancer therapy

Protein kinases have grown over the past few years as a crucial target for different cancer types. With the multifactorial nature of cancer, and the fast development of drug resistance for conventional chemotherapeutics, a strategy for designing multi-target agents was suggested to potentially increase drug efficacy, minimize side effects and retain the proper pharmacokinetic properties. Kinase inhibitors were used extensively in such strategy. Different kinase inhibitor agents which target EGFR, VEGFR, c-Met, CDK, PDK and other targets were merged into hybrids with conventional chemotherapeutics such as tubulin polymerization and topoisomerase inhibitors. Other hybrids were designed gathering kinase inhibitors with targeted cancer therapy such as HDAC, PARP, HSP 90 inhibitors. Nitric oxide donor molecules were also merged with kinase inhibitors for cancer therapy. The current review presents the hybrids designed in the past five years discussing their design principles, results and highlights their future perspectives.

The pre-clinical discovery and development of osimertinib used to treat non-small cell lung cancer

Introduction: Osimertinib is currently the only FDA- and EMA-approved third-generation small-molecule epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI). It was initially indicated for second-line treatment of patients with metastatic EGFR T790M mutation-positive non-small cell lung cancer (NSCLC) and got approved for first-line treatment of EGFR activation mutation-positive metastatic NSCLC in 2018. Most recently, the FDA granted approval for the adjuvant treatment of patients with early-stage mutated EGFR NSCLC after tumor resection.Areas covered: This drug discovery case history focuses on the key studies that led to the preclinical discovery and development of osimertinib. The authors focus on published preclinical studies by scientists from AstraZeneca and highlight key events in the clinical development.Expert opinion: Although eventually compromised by the cellular plasticity of the tumor and the inevitable acquisition of drug resistance through the use of osimertinib, its key role in the treatment of NSCLC with specific EGFR mutations will be maintained in the near future. As the genome of EGFR is highly labile and since the rapid development of new mutants remains an issue, there is still room for improvement for the next generation of inhibitors.

Protein kinase inhibitor-based cancer therapies: Considering the potential of nitric oxide (NO) to improve cancer treatment

The deregulation of a wide variety of protein kinases is associated with cancer cell initiation and tumor progression. Owing to their indispensable function in signaling pathways driving malignant cell features, protein kinases constitute major therapeutic targets in cancer. Over the past two decades, intense efforts in drug development have been dedicated to this field. The development of protein kinase inhibitors (PKIs) have been a real breakthrough in targeted cancer therapy. Despite obvious successes across patients with different types of cancer, the development of PKI resistance still prevails. Combination therapies are part of a comprehensive approach to address the problem of drug resistance. The therapeutic use of nitric oxide (NO) donors to bypass PKI resistance in cancer has never been tested in clinic yet but several arguments suggest that the combination of PKIs and NO donors may exert a potential anticancer effect. The present review summarized the current state of knowledge on common targets to both PKIs and NO. Herein, we attempt to provide the rationale underlying a potential combination of PKIs and NO donors for future directions and design of new combination therapies in cancer.

Characterization and printability of Sodium alginate -Gelatin hydrogel for bioprinting NSCLC co-culture

3D bioprinting improves orientation of in vitro tumor models by offering layer by layer positioning of cancer cells and cancer associated fibroblasts (CAFs) which can replicate tumor microenvironment. Aim of this study was to develop a sodium alginate -gelatin (SA-GL) hydrogel by optimizing rheological parameters to print non-small cell lung cancer (NSCLC) patient derived xenograft (PDX) cells and lung CAFs co-cultures. SA-GL hydrogels were prepared, and rheological properties were evaluated. Both the cells were mixed with the hydrogel and printed using INKREDIBLE bioprinter. Hydrogels prepared with 3.25% and 3.5% (w/v) SA and 4% (w/v) GL showed higher printability and cell viability. A significant decline in viscosity with shear rate was observed in these hydrogels suggesting the shear thinning property of hydrogels. Spheroid size distribution after 15 days was in the diameter range of 50-1100 µm. Up-regulation of vimentin, α-SMA and loss of E-cadherin in co-culture spheroids confirmed cellular crosstalk. This study demonstrates that rheological optimization of SA-GL hydrogel enhances printability and viability of NSCLC PDX and CAF co-culture which allows 3D co-culture spheroid formation within the printed scaffold. Therefore, this model can be used for studying high throughput drug screening and other pre-clinical applications.

FDA- and EMA-Approved Tyrosine Kinase Inhibitors in Advanced EGFR-Mutated Non-Small Cell Lung Cancer: Safety, Tolerability, Plasma Concentration Monitoring, and Management

Non-small-cell lung cancer (NSCLC) is the most common form of primary lung cancer. The discovery of several oncogenic driver mutations in patients with NSCLC has allowed the development of personalized treatments based on these specific molecular alterations, in particular in the tyrosine kinase (TK) domain of the epidermal growth factor receptor (EGFR) gene. Gefitinib, erlotinib, afatinib, and osimertinib are TK inhibitors (TKIs) that specifically target EGFR and are currently approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) as first line treatment for sensitive EGFR-mutant patients. However, these four drugs are associated with severe adverse events (AEs) that can significantly impact patient health-related quality of life and patient monitoring. EGFR-TKIs are commonly used together with other types of medication that can substantially interact. Here, we review approaches used for the management of TKI-AEs in patients with advanced NSCLC to promote the benefits of treatments and minimize the risk of TKI treatment discontinuation. We also consider potential TKI–drug interactions and discuss the usefulness of plasma concentration monitoring TKIs based on chromatographic and mass spectrometry approaches to guide clinical decision-making. Adjusting the most appropriate therapeutic strategies and drug doses may improve the performance therapy and prognosis of patients with advanced EGFR-mutated NSCLC.

Epidermal growth factor receptor tyrosine kinase inhibitors for the treatment of non-small cell lung cancer

Introduction: Epidermal growth factor receptor (EGFR) mutations are well-described drivers of non-small cell lung cancer (NSCLC) and EGFR tyrosine kinase inhibitors (TKIs) have become key components of the NSCLC front-line treatment landscape. Tumors inevitably develop resistance to these agents, and development efforts continue to focus on identifying mechanisms of resistance and drugs to target these mechanisms. Areas covered: With several EGFR TKIs approved for use in the first-line or in later-line settings, an understanding of the efficacy and safety of these inhibitors in various populations is warranted. Furthermore, given the frequent emergence of drug resistance in NSCLC, examination of tumor tissue throughout the disease course provides the opportunity to select treatments based on the tumor's mutation profile. Here, we discuss: key efficacy and safety findings for approved and investigational EGFR TKIs; known mechanisms of resistance, particularly the T790M acquired EGFR mutation; and recent advances in EGFR mutational testing that may facilitate less invasive tissue testing and guide treatment selection. Expert commentary: The expanding armamentarium of EGFR TKIs, improvements in the understanding of resistance mechanisms and technological developments in the molecular analysis of tumors may help render EGFR mutation-positive NSCLC a chronic disease in many patients by facilitating optimal sequential therapy.

Tag-based next generation sequencing: a feasible and reliable assay for EGFR T790M mutation detection in circulating tumor DNA of non small cell lung cancer patients

Background

The demonstration of EGFR T790M gene mutation in plasma is crucial to assess the eligibility of Non Small Cell Lung Cancer (NSCLC) patients, who have acquired resistance to first or second generation Tyrosine Kinase Inhibitors (TKIs), to receive a subsequent treatment with osimertinib. Since circulating tumor DNA (ctDNA) is present in very low amounts in plasma, high sensitive and specific methods are required for molecular analysis.

Improving sensitivity of T790M mutation detection in plasma ctDNA enables a larger number of NSCLC patients to receive the appropriate therapy without any further invasive procedure.

Methods

A tag-based next generation sequencing (NGS) platform capable of tagging rare circulating tumor DNA alleles was employed in this study for the identification of T790M mutation in 42 post-TKI NSCLC patients.

Results

Compared to Real Time PCR, tag-based NGS improved the T790M detection rate (42.85% versus 21.4%, respectively), especially in those cases with a low median mutation abundance (i.e. 0.24, range 0.07–0.78). Moreover, the tag-based NGS identified EGFR activating mutations more efficiently than Real Time PCR (85.7% versus 61.9% detection rate, respectively), particularly of the L858R variant type (0.06–0.75 mutation abundance range). Patients in whom the T790M mutation was detected in plasma, achieved an objective response to osimertinib (9/14, 64.28%).

Conclusions

Tag-based NGS represents an accurate and sensitive tool in a clinical setting for non-invasive assessment and monitoring of T790M variant in NSCLC patients.

Electronic supplementary material

The online version of this article (10.1186/s10020-019-0082-5) contains supplementary material, which is available to authorized users.

Does c-Met remain a rational target for therapy in patients with EGFR TKI-resistant non-small cell lung cancer?

Non-small cell lung cancer (NSCLC) inevitably develops resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) treatment. In 5-20% of cases, this can be attributed to aberrant c-Met activity, providing a clear rationale for the use of c-Met inhibitors in these patients. EGFR TKI-resistant tumors often remain sensitive to EGFR signaling, such that c-Met inhibitors are likely to be most effective when combined with continued EGFR TKI therapy. The phase III trials of the c-Met inhibitors onartuzumab and tivantinib, which failed to demonstrate significant benefit in patients with NSCLC but excluded patients with EGFR TKI-resistant disease, do not allow c-Met to be dismissed as a rational target in EGFR TKI-resistant NSCLC. Selective c-Met TKIs exhibit more favorable properties, targeting both hepatocyte growth factor (HGF)-dependent and -independent c-Met activity, with a reduced risk of toxicity compared to non-selective c-Met TKIs. Phase Ib/II trials of the selective c-Met TKIs capmatinib and tepotinib have shown encouraging signs of efficacy. Factors affecting the success of ongoing and future trials of c-Met inhibitors in patients with EGFR TKI-resistant, c-Met-positive NSCLC are considered.

Association between clinical characteristics and the diagnostic accuracy of circulating single-molecule amplification and resequencing technology on detection epidermal growth factor receptor mutation status in plasma of lung adenocarcinoma

BACKGROUND

Lung cancer is the leading cause of cancer-related mortality in the world. Circulating single-molecule amplification and resequencing technology (cSMART) can successfully detect epidermal growth factor receptor (EGFR) mutation in non-small cell lung cancer (NSCLC). However, few studies have investigated the association between clinical characteristics and the diagnostic accuracy of cSMART technique in lung adenocarcinoma.

METHODS

We enrolled 95 patients, which included paraffin embedded tumor tissues and matched plasma samples. Retrospectively analyzed the correlation between clinical characteristics and sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of cSMART.

RESULTS

Of the 95 lung adenocarcinoma cancer patients, 49 (51.5%) and 40 (42.1%) harbored EGFR mutations respectively in tissue and plasma. In younger than 60 years group, sensitivity, specificity and consistency for cSMART were 81.0%, 100%, and 90.9% (P<.001). In metastasis group, sensitivity, specificity, and consistency for cSMART were 92.9%, 77.8%, and 87.0% (P=.001). By univariate analysis, younger than 60 years (OR=5.938; 95% confidence interval: 1.835-19.210; P=.001); metastasis group (OR=4.482; 95% confidence interval: 1.432-14.024; P=.007) were significantly correlated with a higher accuracy. By multivariate analysis, younger than 60 years (P=.003) and metastasis (P=.004) were confirmed as independent factors for diagnostic accuracy of EGFR mutation in plasma through cSMART.

CONCLUSION

cSMART is feasible for detection EGFR mutation in plasma when tissue is unavailable. Age and metastasis might be considered as independent factors in diagnostic accuracy of cSMART in lung adenocarcinoma.

Protein functional effector sncRNAs (pfeRNAs) in lung cancer

PIWI-interacting RNA Likes (piR-Ls) were recently reported to regulate functions of their target phospho-Proteins (p-Proteins) in somatic lung cells. However, the mechanism underlying this functionality remains unclear. piR-Ls interact with their targets through direct binding but do not follow base-pairing rules, known to have important roles at levels of transcription, RNA processing and translation for small non-coding RNA (sncRNA). These observations imply a fundamentally different type of sncRNA with behavior that causes a molecular response in their target p-Proteins. Furthermore, the interaction of piR-Ls with their targets regulates the functional efficacy of target p-Proteins. In addition, except for writers (kinase) and erasers (phosphatase), the functional efficacy of p-Proteins on their readers still remains unknown. It is reasonable to consider the existence of protein functional effector sncRNAs (pfeRNAs), which were identified by deep sequencing the immunoprecipitation products of antibodies targeting phosphorylated residues in proteins, as well as by functional analysis. pfeRNAs harbor unique features in size distribution, 3' terminal modification, shared core sequences, and functional manner, and could be new players in lung physiological and pathological conditions.

A phosphorylation-wide sncRNA screen reveals Protein Functional Effector sncRNAs (pfeRNAs) in human lung somatic cells

We recently reported that PIWI-interacting RNAs likes (piR-Ls) could regulate functions of the interacting phosphorylated proteins (p-Proteins). In addition, except for writers and erasers, functional efficacy of p-Proteins on their readers still remains unknown. We, therefore, reasoned there was a type of sncRNAs which could regulate functional efficacy of p-Proteins. Here, we profiled sncRNAs interacting with phosphorylated -Ser, -Thr and -Tyr residues in 3 HBE and 4 lung SCC cell lines, investigated effects and mechanisms of phosphorylated-residue-interacting sncRNAs. Our results demonstrated sncRNAs regulating functional efficacy of p-Proteins and we thus referred them as Protein Functional Effector sncRNAs (pfeRNAs). pfeRNAs were distributed among 26 to 50 nucleotides, shared some core sequences and showed distinctive expression patterns between HBE and SCC cells. Core sequences 417 (CS417), showing consistent upregulation in all 4 SCC cells, bound directly to p-Nucleolin (NCL), which was dependent on the key elements CGCG of CS417 and p-Ser619 of NCL. The CS417/p-NCL interaction was critical for functional efficacy of p-NCL in basic activities of lung normal and cancer cells. Thus, we revealed a novel type of pfeRNAs controlling functional efficacy of p-Proteins in lung somatic cells.

Relationship between serum carcinoembryonic antigen level and epidermal growth factor receptor mutations with the influence on the prognosis of non-small-cell lung cancer patients

OBJECTIVE

To investigate the relationship between serum carcinoembryonic antigen (CEA) level and epidermal growth factor receptor (EGFR) gene mutations in non-small-cell lung cancer (NSCLC) patients and to analyze the influence of CEA level on postoperative survival time in lung cancer patients.

METHODS

A total of 296 patients who were treated in Thoracic Surgery Department of Henan Provincial Chest Hospital from September 2011 to September 2013 were recruited. The level of tumor markers, such as CEA, was determined before the surgery, and EGFR gene mutations were detected after surgery. Thereby, the relationship between tumor makers, including CEA, and EGFR mutation and its influence on prognosis could be investigated.

RESULTS

Among 296 patients, the positive rate of EGFR gene mutation was 37.84% (112/296); the mutation occurred more frequently in nonsmokers, adenocarcinoma patients, women, and patients aged <60 years (P<0.05). Both tumor markers and chemosensitivity indicators were related to the profile of EGFR mutations. Elevated squamous cell carcinoma and Cyfra21-1 as well as positively expressed ERCC1 were more common in patients with wild-type EGFR (P<0.05), whereas increased CEA level was observed more frequently in patients with EGFR gene mutation (P=0.012). The positive rate of EGFR gene mutations was higher as the serum CEA level increased, that is, the positive rate in patients with serum CEA level <5, 5-20, and >20 μg/L was 39.81%, 45.32%, and 65.47%, respectively (P=0.004). Logistic regression analysis showed that CEA level was an independent factor in predicting EGFR gene mutations, and serum CEA level was also an independent factor in affecting the prognosis of NSCLC patients, as the overall 2-year survival rate was 73.86% in elevated CEA group and 86.43% in normal group (P<0.01).

CONCLUSION

The prognosis of NSCLC patients receiving resection can be predicted according to serum CEA level, which is associated with EGFR mutations in NSCLC patients and provides a preliminarily guidance for EGFR mutations.

Hereditary lung cancer syndrome targets never smokers with germline EGFR gene T790M mutations

INTRODUCTION

Hereditary lung cancer syndromes are rare, and T790M germline mutations of the epidermal growth factor receptor (EGFR) gene predispose to the development of lung cancer. The goal of this study was to determine the clinical features and smoking status of lung cancer cases and unaffected family members with this germline mutation and to estimate its incidence and penetrance.

METHODS

We studied a family with germline T790M mutations over five generations (14 individuals) and combined our observations with data obtained from a literature search (15 individuals).

RESULTS

T790M germline mutations occurred in approximately 1% of non-small-cell lung cancer cases and in less than one in 7500 subjects without lung cancer. Both sporadic and germline T790M mutations were predominantly adenocarcinomas, favored female gender, and were occasionally multifocal. Of lung cancer tumors arising in T790M germline mutation carriers, 73% contained a second activating EGFR gene mutation. Inheritance was dominant. The odds ratio that T790M germline carriers who are smokers will develop lung cancer compared with never smoker carriers was 0.31 (p = 6.0E-05). There was an overrepresentation of never smokers with lung cancer with this mutation compared with the general lung cancer population (p = 7.4E-06).

CONCLUSION

Germline T790M mutations result in a unique hereditary lung cancer syndrome that targets never smokers, with a preliminary estimate of 31% risk for lung cancer in never smoker carriers, and this risk may be lower for heavy smokers. The resultant cancers share several features and differences with lung cancers containing sporadic EGFR mutations.

CIP4 promotes lung adenocarcinoma metastasis and is associated with poor prognosis

Aberrant Epidermal growth factor receptor (EGFR) signaling in non-small cell lung cancer (NSCLC) is linked to tumor progression, metastasis, and poor survival rates. Here, we report the role of Cdc42-interacting protein 4 (CIP4) in the regulation of NSCLC cell invasiveness and tumor metastasis. CIP4 was highly expressed in a panel of NSCLC cell lines and normal lung epithelial cell lines. Stable knock-down (KD) of CIP4 in lung adenocarcinoma H1299 cells, expressing wild-type EGFR, led to increased EGFR levels on the cell surface, and defects in sustained activation of Erk kinase in H1299 cells treated with EGF. CIP4 localized to leading edge projections in NSCLC cells, and CIP4 KD cells displayed defects in EGF-induced cell motility and invasion through extracellular matrix. This correlated with reduced expression and activity of matrix metalloproteinase-2 (MMP-2) in CIP4 KD cells compared to control. In xenograft assays, CIP4 silencing had no effect on tumor growth, but resulted in significant defects in spontaneous metastases to the lungs from these subcutaneous tumors. This correlated with reduced expression of the Erk target gene Zeb1, and the Zeb1 target gene MMP-2 in CIP4 KD tumors compared to control. CIP4 also enhanced rates of metastasis to the liver and lungs in an intrasplenic experimental metastasis model. In human NSCLC tumor sections, CIP4 expression was elevated ≥ 2-fold in 43% of adenocarcinomas and 32% of squamous carcinomas compared to adjacent normal lung tissues. Analysis of microarray data for NSCLC patients also revealed that high CIP4 transcript levels correlated with reduced overall survival. Together, these results identify CIP4 as a positive regulator of NSCLC metastasis, and a potential poor prognostic biomarker in lung adenocarcinoma.

Silibinin suppresses EMT-driven erlotinib resistance by reversing the high miR-21/low miR-200c signature in vivo

The flavolignan silibinin was studied for its ability to restore drug sensitivity to EGFR-mutant NSCLC xenografts with epithelial-to-mesenchymal transition (EMT)-driven resistance to erlotinib. As a single agent, silibinin significantly decreased the tumor volumes of erlotinib-refractory NSCLC xenografts by approximately 50%. Furthermore, the complete abrogation of tumor growth was observed with the co-treatment of erlotinib and silibinin. Silibinin fully reversed the EMT-related high miR-21/low miR-200c microRNA signature and repressed the mesenchymal markers SNAIL, ZEB, and N-cadherin observed in erlotinib-refractory tumors. Silibinin was sufficient to fully activate a reciprocal mesenchymal-to-epithelial transition (MET) in erlotinib-refractory cells and prevent the highly migratogenic phenotype of erlotinib-resistant NSCLC cells. Given that the various mechanisms of resistance to erlotinib result from EMT, regardless of the EGFR mutation status, a water-soluble, silibinin-rich milk thistle extract might be a suitable candidate therapy for upcoming clinical trials aimed at preventing or reversing NSCLC progression following erlotinib treatment.

Updates on immunotherapy in non-small cell lung cancer

Immunotherapy has made significant progress in patients with non-small cell lung cancer (NSCLC) in the last years. Early tumor vaccine studies showed trends toward better clinical outcomes, and larger trial results are currently being awaited. Immune checkpoint inhibitors are promising therapeutic agents in advanced NSCLC. While ipilimumab, a cytotoxic T-lymphocyte antigen 4 inhibitor, has clearly improved outcomes in metastatic malignant melanoma, its safety and efficacy in NSCLC are not yet known. Programmed death-1 (PD-1) and PD-1 ligand inhibitors such as nivolumab, MK3475 and MPDL3280 have demonstrated clinical efficacy in patients with advanced/metastatic NSCLC in early clinical trials. Their validation in larger Phase III trials is anxiously being awaited. Furthermore, exploring efficacy of these molecules in patients with early stages of lung cancer is also necessary.

Phase I dosage finding and pharmacokinetic study of intravenous topotecan and oral erlotinib in adults with refractory solid tumors

PURPOSE

Topotecan is widely used for refractory solid tumors but multi-drug resistance may occur due to tumor expression of ATP-binding cassette (ABC) transporters. Since erlotinib, an inhibitor of the epidermal growth factor receptor, also inhibits several ABC transporters, we performed a phase I study to evaluate the safety, efficacy, and pharmacokinetics of intravenous topotecan given in combination with erlotinib.

METHODS

Patients received 150 mg of oral erlotinib daily and a 30 min intravenous infusion of topotecan on days 1-5 of a 21-day cycle. Dosage escalation of topotecan occurred with a starting dosage of 0.75 mg/m(2). The pharmacokinetics of topotecan was evaluated on day 1 of cycle 1 without erlotinib and on day 1 of cycle 2 or 3 with erlotinib.

RESULTS

Twenty-nine patients were enrolled. The maximum tolerated dosage was determined to be 1.0 mg/m(2). Dose-limiting toxicities included neutropenia and thrombocytopenia. The average duration of treatment was 97 days. Two partial responses were observed. Topotecan clearance and exposure were similar with and without erlotinib.

CONCLUSIONS

The combination of topotecan and erlotinib is tolerable at clinically effective doses. Erlotinib does not affect the disposition of topotecan to a clinically significant extent.

Stem cell-like ALDH(bright) cellular states in EGFR-mutant non-small cell lung cancer: a novel mechanism of acquired resistance to erlotinib targetable with the natural polyphenol silibinin

The enrichment of cancer stem cell (CSC)-like cellular states has not previously been considered to be a causative mechanism in the generalized progression of EGFR-mutant non-small cell lung carcinomas (NSCLC) after an initial response to the EGFR tyrosine kinase inhibitor erlotinib. To explore this possibility, we utilized a pre-clinical model of acquired erlotinib resistance established by growing NSCLC cells containing a TKI-sensitizing EGFR exon 19 deletion (ΔE746-A750) in the continuous presence of high doses of erlotinib. Genome-wide analyses using Agilent 44K Whole Human Genome Arrays were evaluated via bioinformatics analyses through GSEA-based screening of the KEGG pathway database to identify the molecular circuitries that were over-represented in the transcriptomic signatures of erlotinib-refractory cells. The genomic spaces related to erlotinib resistance included a preponderance of cell cycle genes (E2F1, - 2, CDC2, -6) and DNA replication-related genes (MCM4, - 5, - 6, - 7), most of which are associated with early lung development and poor prognosis. In addition, metabolic genes such as ALDH1A3 (a candidate marker for lung cancer cells with CSC-like properties) were identified. Thus, we measured the proportion of erlotinib-resistant cells expressing very high levels of aldehyde dehydrogenase (ALDH) activity attributed to ALDH1/3 isoforms. Using flow cytometry and the ALDEFLUOR® reagent, we confirmed that erlotinib-refractory cell populations contained drastically higher percentages (> 4500%) of ALDH(bright) cells than the parental erlotinib-responsive cells. Notably, strong decreases in the percentages of ALDH(bright) cells were observed following incubation with silibinin, a bioactive flavonolignan that can circumvent erlotinib resistance in vivo. The number of lung cancer spheres was drastically suppressed by silibinin in a dose-dependent manner, thus confirming the ability of this agent to inhibit the self-renewal of erlotinib-refractory CSC-like cells. This report is the first to show that: (1) loss of responsiveness to erlotinib in EGFR-mutant NSCLC can be explained in terms of erlotinib-refractory ALDH(bright) cells, which have been shown to exhibit stem cell-like properties; and (2) erlotinib-refractory ALDH(bright) cells are sensitive to the natural agent silibinin. Our findings highlight the benefit of administration of silibinin in combination with EGFR TKIs to target CSCs and minimize the ability of tumor cells to escape cell death in EGFR-mutant NSCLC patients.

Oncogenic driver mutations in lung cancer

Lung cancer is a heterogeneous and complex disease. Genomic and transcriptomic profiling of lung cancer not only further our knowledge about cancer initiation and progression, but could also provide guidance on treatment decisions. The fact that targeted treatment is most successful in a subset of tumors indicates the need for better classification of clinically related molecular tumor phenotypes based on better understanding of the mutations in relevant genes, especially in those oncogenic driver mutations. EGFR gene mutations, KRAS gene mutations, EML4-ALK rearrangements and altered MET signaling are widely recognized alterations that play important roles in both the biological mechanisms and the clinical sensitivity to treatment in lung cancer. In this article, we reviewed the discovery of the clinical values of these oncogenic driver mutations and the clinical studies revealing the prognostic and predictive values of these biomarkers for clinical sensitivity and resistance to anti-EGFR therapy or other targeted therapies. These form the basis of personalized treatment in lung cancer based on biomarker profiles of individual tumor, leading to therapeutic advancement and betterment.

Trivanillic polyphenols with anticancer cytostatic effects through the targeting of multiple kinases and intracellular Ca2+ release

Cancer cells exhibit de-regulation of multiple cellular signalling pathways and treatments of various types of cancers with polyphenols are promising. We recently reported the synthesis of a series of 33 novel divanillic and trivanillic polyphenols that displayed anticancer activity, at least in vitro, through inhibiting various kinases. This study revealed that minor chemical modifications of a trivanillate scaffold could convert cytotoxic compounds into cytostatic ones. Compound 13c, a tri-chloro derivative of trivanillic ester, displayed marked inhibitory activities against FGF-, VEGF-, EGF- and Src-related kinases, all of which are implicated not only in angiogenesis but also in the biological aggressiveness of various cancer types. The pan-anti-kinase activity of 13c occurs at less than one-tenth of its mean IC₅₀in vitro growth inhibitory concentrations towards a panel of 12 cancer cell lines. Of the 26 kinases for which 13c inhibited their activity by >75%, eight (Yes, Fyn, FGF-R1, EGFR, Btk, Mink, Ret and Itk) are implicated in control of the actin cytoskeleton organization to varying degrees. Compound 13c accordingly impaired the typical organization of the actin cytoskeleton in human U373 glioblastoma cells. The pan-anti-kinase activity and actin cytoskeleton organization impairment provoked by 13c concomitantly occurs with calcium homeostasis impairment but without provoking MDR phenotype activation. All of these anticancer properties enabled 13c to confer therapeutic benefits in vivo in a mouse melanoma pseudometastatic lung model. These data argue in favour of further chemically modifying trivanillates to produce novel and potent anticancer drugs.

Anaplastic lymphoma kinase gene rearrangements in non-small cell lung cancer are associated with prolonged progression-free survival on pemetrexed

HYPOTHESIS

To explore whether the progression-free survival (PFS) with pemetrexed differs between anaplastic lymphoma kinase (ALK)-positive and other major molecular subtypes of non-small cell lung cancer.

METHODS

In an ALK-enriched population, patients with metastatic non-small cell lung cancer were screened by ALK fluorescence in situ hybridization and for epidermal growth factor receptor (EGFR) and KRAS mutations. Triple-tested, pemetrexed-treated patients (monotherapy or combination therapy) were identified and PFS with pemetrexed captured retrospectively.

RESULTS

Eighty-nine eligible cases were identified (19 ALK fluorescence in situ hybridization positive, 12 EGFR mutant, 21 KRAS mutant, and 37 triple negatives). Eighty-three cases (93%) were adenocarcinomas, two were adenosquamous, one squamous, and three had large cell histology. None of the ALK-positive patients had received crizotinib before pemetrexed. Pemetrexed was first-line therapy in 48% (72% as platinum-based combinations). Median PFS (95% confidence interval) data were EGFR mutant (5.5 months; 1-9), KRAS mutant (7 months; 1.5-10), ALK positive (9 months; 3-12), and triple negative (4 months; 3-5). In a multivariate analysis adjusting for line of therapy, mono- versus platinum and nonplatinum combination therapy, age, sex, histology, and smoking status, the only variable associated with prolonged PFS on pemetrexed was ALK+ (hazard ratio = 0.36 [95% confidence interval: 0.17-0.73], p = 0.0051).

CONCLUSIONS

In this exploratory analysis, ALK-positive patients have a significantly longer PFS on pemetrexed compared with triple-negative patients, whereas EGFR or KRAS mutant patients do not. This information should be considered when sizing randomized studies in ALK-positive patients that involve pemetrexed. Pemetrexed should also be prioritized as a cytotoxic to explore further in patients with known ALK-positive disease.

Clinical characteristics of Japanese lung cancer patients with human immunodeficiency virus infection

BACKGROUND

Lung cancer has emerged as a crucial problem among human immunodeficiency virus (HIV)-infected patients, contributing to significant mortality in Western countries. Japan has an increasing number of newly infected HIV patients, but clinical characteristics of lung cancer have not been well investigated in Asian populations with HIV.

PATIENTS AND METHODS

We retrospectively analyzed patients diagnosed with HIV and lung cancer simultaneously in our institution between 1985 and 2010. Data regarding HIV status, characteristics, treatment, and prognosis of lung cancer were evaluated.

RESULTS

We identified 13 consecutive patients (all men; mean age, 59.0 ± 10.2 years) since 1985, 7 of whom had been diagnosed since 2008. Mean CD4 cell count was 332 ± 159 cells/μL, and HIV viral loads were undetectable in 8 patients (61.5%) at the time of lung cancer diagnosis. The mean latency from HIV diagnosis to detection of lung cancer was 4.0 years. Histological examination demonstrated adenocarcinoma in 9 patients (69.2%), followed by squamous cell carcinoma (23.1%), and small cell carcinoma (7.7%). Among the 7 patients available for examination, 2 patients (28.6%) harbored EGFR mutation. Six patients had stage IA-IIIA, and 7 patients had stage IIIB/IV. Among 6 patients treated with chemotherapy for unresectable stages, 5 (83.3%) achieved a partial response. Median overall survival was 17 months for all stages and 14 months for advanced stages. Toxicities for treatment modalities were largely acceptable.

CONCLUSIONS

Clinical characteristics of Japanese HIV-infected patients with lung cancer resemble those of Western populations. The prognosis for patients in the metastatic stage was better than previously reported.

Stem cell property epithelial-to-mesenchymal transition is a core transcriptional network for predicting cetuximab (Erbitux™) efficacy in KRAS wild-type tumor cells

Beyond a well-recognized effect of KRAS mutations in determining de novo inefficacy of cetuximab (CTX) in metastatic colorectal cancer, we urgently need a biomarker signature for predicting CTX efficacy in KRAS wild-type (WT) tumors. CTX-adapted EGFR gene-amplified KRAS WT tumor cell populations were induced by stepwise-chronic exposure of A431 epidermoid cancer cells to CTX. Genome-wide analyses of 44K Agilent's whole human arrays were bioinformatically evaluated by Gene Set Enrichment Analysis (GSEA)-based screening of the KEGG pathway database. Molecular functioning of CTX was found to depend on: (i) The occurrence of a positive feedback loop on Epidermal Growth Factor Receptor (EGFR) activation driven by genes coding for EGFR ligands (e.g., amphiregulin); (ii) the lack of a negative feedback on mitogen-activated protein kinase (MAPK) activation regulated by dual-specificity phosphatases (e.g., DUSP6) and; (iii) the transcriptional status of gene pathways controlling the epithelial-to-mesenchymal transition (EMT) and its reversal (MET) program (actin cytoskeleton and cell-cell communication-e.g., keratins-focal adhesion signaling-e.g., integrins-and EMT-inducing cytokines - e.g., transforming growth factor-β). Quantitative real-time PCR, high-content immunostaining, and flow-cytometry analyses confirmed that CTX efficacy depends on its ability to promote: (i) Stronger cell-cell contacts by up-regulating the expression of the epithelial markers E-cadherin and occludin; (ii) down-regulation of the epithelial transcriptional repressors Zeb, Snail, and Slug accompanied by restoration of cortical F-actin; and (iii) complete prevention of the CD44(pos)/CD24(neg/low) mesenchymal immunophenotype. The impact of EGFR ligands/MAPK phosphatases gene transcripts in predicting CTX efficacy in KRAS WT tumors may be tightly linked with the ability of CTX to concurrently reverse the EMT status, a pivotal property of migrating cancer stem cells.

Assessment of epidermal growth factor receptor and K-ras mutation status in cytological stained smears of non-small cell lung cancer patients: correlation with clinical outcomes

OBJECTIVE

Epidermal growth factor receptor (EGFR) and K-ras mutations guide treatment selection in non-small cell lung cancer (NSCLC) patients. Although mutation status is routinely assessed in biopsies, cytological specimens are frequently the only samples available. We determined EGFR and K-ras mutations in cytological samples.

METHODS

DNA was extracted from 150 consecutive samples, including 120 Papanicolau smears (80%), 10 cell blocks (7%), nine fresh samples (6%), six ThinPrep® tests (4%), and five body cavity fluids (3.3%). Papanicolau smears were analyzed when they had >50% malignant cells. Polymerase chain reaction and direct sequencing of exons 18-21 of EGFR and exon 2 of K-ras were performed. EGFR mutations were simultaneously determined in biopsies and cytological samples from 20 patients. Activity of EGFR tyrosine kinase inhibitors (TKIs) was assessed.

RESULTS

The cytological diagnosis was adenocarcinoma in 110 samples (73%) and nonadenocarcinoma in 40 (27%) samples. EGFR mutations were identified in 26 samples (17%) and K-ras mutations were identified in 18 (12%) samples. EGFR and K-ras mutations were mutually exclusive. In EGFR-mutated cases, DNA was obtained from stained smears in 24 cases (92%), pleural fluid in one case (4%), and cell block in one case (4%). The response rate to EGFR TKIs in patients harboring mutations was 75%. The mutation status was identical in patients who had both biopsies and cytological samples analyzed.

CONCLUSION

Assessment of EGFR and K-ras mutations in cytological samples is feasible and comparable with biopsy results, making individualized treatment selection possible for NSCLC patients from whom tumor biopsies are not available.

Detection of EGFR mutations with mutation-specific antibodies in stage IV non-small-cell lung cancer

Background

Immunohistochemistry (IHC) with mutation-specific antibodies may be an ancillary method of detecting EGFR mutations in lung cancer patients.

Methods

EGFR mutation status was analyzed by DNA assays, and compared with IHC results in five non-small-cell lung cancer (NSCLC) cell lines and tumor samples from 78 stage IV NSCLC patients.

Results

IHC correctly identified del 19 in the H1650 and PC9 cell lines, L858R in H1975, and wild-type EGFR in H460 and A549, as well as wild-type EGFR in tumor samples from 22 patients. IHC with the mAb against EGFR with del 19 was highly positive for the protein in all 17 patients with a 15-bp (ELREA) deletion in exon 19, whereas in patients with other deletions, IHC was weakly positive in 3 cases and negative in 9 cases. IHC with the mAb against the L858R mutation showed high positivity for the protein in 25/27 (93%) patients with exon 21 EGFR mutations (all with L858R) but did not identify the L861Q mutation in the remaining two patients.

Conclusions

IHC with mutation-specific mAbs against EGFR is a promising method for detecting EGFR mutations in NSCLC patients. However these mAbs should be validated with additional studies to clarify their possible role in routine clinical practice for screening EGFR mutations in NSCLC patients.

Evolution of the predictive markers amphiregulin and epiregulin mRNAs during long-term cetuximab treatment of KRAS wild-type tumor cells

Molecular mechanisms other than activating KRAS mutations should underlie the occurrence of weaker versus stronger responses to cetuximab (CTX) in EGFR-dependent carcinomas with either an intact KRAS signaling or in which KRAS mutations do not predict CTX efficacy. We hypothesized that KRAS wild-type (WT) tumor cell-line models chronically adapted to grow in the presence of CTX could be interrogated to establish if the positive predictive value of the mRNAs coding for the EGFR ligands amphiregulin (AR) and epiregulin (EPI) could be significantly altered during and/or after treatment with CTX. Gene expression analyses using real-time (kinetic) RT-PCR were performed to monitor the transcriptional evolution of EGFR ligands EGF, TGFα, AR, BTC, EPI, NRG and HB-EGF in experimental modes induced to exhibit acquired resistance to the mono-HER1 inhibitor CTX, the mono-HER2 inhibitor trastuzumab (Tzb) or the dual HER1/HER2 inhibitor lapatinib (LPT). Gene expression signatures for EGFR ligands distinctively related to the occurrence of unresponsiveness to CTX, Tzb or LPT, with minimal overlap between them. CTX's molecular functioning largely depended on the overproduction of the mRNAs coding for the EGFR ligands AR and EPI. Thus, a dramatic down-regulation of AR/EPI mRNA expression occurred upon loss of CTX efficacy in EGFR-positive tumor cells with an intact regulation of RAS signaling. Unlike KRAS mutations, which are informative of unresponsiveness to CTX solely in mCRC, our hypothesis-generating data suggest that expression status of AR and EPI mRNAs might be evaluated as dynamic predictors of response in KRAS WT patients receiving any CTX-based therapy.

EGFR inhibitor C225 increases the radiosensitivity of human lung squamous cancer cells

Background

The purpose of the present study is to investigate the direct biological effects of the epidermal growth factor receptor (EGFR) inhibitor C225 on the radiosensitivity of human lung squamous cancer cell-H520. H520 cells were treated with different dosage of ⁶⁰Co γ ray irradiation (1.953 Gy/min) in the presence or absence of C225. The cellular proliferation, colony forming capacity, apoptosis, the cell cycle distribution as well as caspase-3 were analyzed in vitro.

Results

We found that C225 treatment significantly increased radiosensitivity of H-520 cells to irradiation, and led to cell cycle arrest in G₁ phase, whereas ⁶⁰Co γ ray irradiation mainly caused G₂ phase arrest. H-520 cells thus displayed both the G₁ and G₂ phase arrest upon treatment with C225 in combination with ⁶⁰Co γ ray irradiation. Moreover, C225 treatment significantly increased the apoptosis percentage of H-520 cells (13.91% ± 1.88%) compared with the control group (5.75% ± 0.64%, P < 0.05).

Conclusion

In this regard, C225 treatment may make H-520 cells more sensitive to irradiation through the enhancement of caspase-3 mediated tumor cell apoptosis and cell cycle arrest.