Gefitinib-sensitizing EGFR mutations in lung cancer activate anti-apoptotic pathways

Risk stratification and adjuvant chemotherapy after radical resection based on the clinical risk scores of patients with stage IB-IIA non-small cell lung cancer

INTRODUCTION

Despite the heterogeneity among patients with stage IB-IIA non-small cell lung cancer (NSCLC), clinically applicable models to identify patients most suitable for receiving adjuvant chemotherapy (ACT) are limited. We aimed to develop a model for risk stratification and the individualized application of ACT.

METHODS

Between January 2008 and March 2018, patients with T2N0M0 NSCLC at Sun Yat-sen University Cancer Center were retrospectively enrolled. Survival curves were estimated by Kaplan-Meier method and compared with log-rank test. Cox regression models were used to identify prognostic factors for disease-free survival (DFS) and overall survival (OS). Propensity score matching (PSM) was implemented. Subgroup analysis was performed based on clinical risk score (CRS) value and epidermal growth factor receptor (EGFR) mutation status.

RESULTS

Of 1063 patients with T2N0 NSCLC enrolled, 272 patients received ACT. Before PSM, patients with high CRS (>1) had a significantly worse OS and DFS outcomes. In the PSM, the baseline characteristics of the 270 pairs of patients were well matched. ACT was associated with improved OS outcomes for patients with a high CRS, while ACT was associated with improved OS and DFS outcomes in patients with wild-type EGFR. The interaction analysis showed an apparent interaction effect between ACT and EGFR-activating mutations as well as chemotherapy regimens and histology.

CONCLUSIONS

The CRS can predict the prognosis of patients with stage IB-IIA NSCLC. ACT could improve the outcome of patients with a high CRS. Patients with non-squamous cell histology receiving pemetrexed plus platinum might benefit more, but not those with EGFR-activating mutations.

PLK1 (polo like kinase 1)-dependent autophagy facilitates gefitinib-induced hepatotoxicity by degrading COX6A1 (cytochrome c oxidase subunit 6A1)

Liver dysfunction is an outstanding dose-limiting toxicity of gefitinib, an EGFR (epidermal growth factor receptor)-tyrosine kinase inhibitor (TKI), in the treatment of EGFR mutation-positive non-small cell lung cancer (NSCLC). We aimed to elucidate the mechanisms underlying gefitinib-induced hepatotoxicity, and provide potentially effective intervention strategy. We discovered that gefitinib could sequentially activate macroautophagy/autophagy and apoptosis in hepatocytes. The inhibition of autophagy alleviated gefitinib-induced apoptosis, whereas the suppression of apoptosis failed to lessen gefitinib-induced autophagy. Moreover, liver-specific Atg7+/- heterozygous mice showed less severe liver injury than vehicle, suggesting that autophagy is involved in the gefitinib-promoted hepatotoxicity. Mechanistically, gefitinib selectively degrades the important anti-apoptosis factor COX6A1 (cytochrome c oxidase subunit 6A1) in the autophagy-lysosome pathway. The gefitinib-induced COX6A1 reduction impairs mitochondrial respiratory chain complex IV (RCC IV) function, which in turn activates apoptosis, hence causing liver injury. Notably, this autophagy-promoted apoptosis is dependent on PLK1 (polo like kinase 1). Both AAV8-mediated Plk1 knockdown and PLK1 inhibitor BI-2536 could mitigate the gefitinib-induced hepatotoxicity in vivo by abrogating the autophagic degradation of the COX6A1 protein. In addition, PLK1 inhibition could not compromise the anti-cancer activity of gefitinib. In conclusion, our findings reveal the gefitinib-hepatotoxicity pathway, wherein autophagy promotes apoptosis through COX6A1 degradation, and highlight pharmacological inhibition of PLK1 as an attractive therapeutic approach toward improving the safety of gefitinib-based cancer therapy.Abbreviations: 3-MA: 3-methyladenine; AAV8: adeno-associated virus serotype 8; ATG5: autophagy related 5; ATG7: autophagy related 7; B2M: beta-2-microglobulin; CCCP: carbonyl cyanide m-chlorophenylhydrazone; CHX: cycloheximide; COX6A1: cytochrome c oxidase subunit 6A1; c-PARP: cleaved poly(ADP-ribose) polymerase; CQ: chloroquine; GOT1/AST: glutamic-oxaloacetic transaminase 1, soluble; GPT/ALT: glutamic pyruvic transaminase, soluble; HBSS: Hanks´ balanced salt solution; H&E: hematoxylin and eosin; MAP1LC3/LC3: microtubule associated proteins 1 light chain 3; PLK1: polo like kinase 1; RCC IV: respiratory chain complex IV; ROS: reactive oxygen species; TUBB8: tubulin beta 8 class VIII.

Impact of angiogenesis inhibitor eligibility on the prognosis of patients with non-small cell lung cancer harboring EGFR mutation

Background

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR‐TKIs) are currently the primary treatment option for patients with EGFR‐mutant non‐small cell lung cancer (NSCLC). However, the effect of EGFR‐TKIs are eventually weakened due to resistance, and there is also a differential efficacy based on EGFR mutation subtypes. The combination of angiogenesis inhibitor (AI) with EGFR‐TKI has shown better efficacy than EGFR‐TKI monotherapy, regardless of the mutation subtypes. Nevertheless, the effect of AI eligibility on overall survival (OS) and progression‐free survival (PFS) remains to be elucidated. Thus, we assessed this impact on patients with NSCLC harboring EGFR mutation.

Methods

In this study, the data for 450 patients with EGFR‐mutant NSCLC, who were treated with EGFR‐TKI monotherapy, were retrospectively analyzed for AI eligibility. The patients were categorized into AI‐eligible (AI fit) and ineligible groups (AI unfit).

Results

The median PFS of the AI fit group was 12.9 months, compared to 9.6 months in the unfit group (p = 0.007), and OS was also significantly longer in the AI fit group (median OS = 33.0 months) compared to that in the unfit group (18.5 months, p < 0.001). Multivariate analysis indicated that AI ineligibility was associated with shorter PFS and poor prognosis. Also, in the AI fit group, there was no significant difference in the PFS between EGFR L858R mutation and EGFR exon 19 deletion (median PFS = 11.5 months vs. 13.8 months; p = 0.17).

Conclusions

From our study, AI eligibility resulted in longer OS and PFS, and also had different effects on patients with EGFR L858R and exon 19 deletion. Since this selection bias may have affected previous clinical trial data on the efficacy of AI combination therapy, their results should be carefully considered henceforth.

Light-driven photoswitching of quinazoline analogues of combretastatin A-4 as an effective approach for targeting skin cancer cells

A novel quinazoline series of photoswitchable combretastatin A-4 (CA-4) analogues were synthesized and their photochemical properties and antiproliferative activity against A431 epidermoid carcinoma cells were studied. It was found that quinazoline analogues, in contrast to the majority of the known CA-4, exhibit high antiproliferative activity in the E-form as well. Photoswitching of the E-form to the Z-form resulted in a multiple (9-fold) increase in antiproliferative activity. 1H NMR monitoring showed that these compounds are very resistant to UV (λ = 365 nm) or sunlight irradiation and do not undergo photodegradation with a loss of antiproliferative activity that is inherent in heterocyclic analogues of CA-4. Similar photoswitching and an increase in antiproliferative activity are observed on exposure to sunlight. A selected compound (1a-Z51) in sub-micromolar concentrations induced apoptosis in A431 cells, while rad50/ATM/p53 were not involved in cell death. The growth of A431 cells was significantly inhibited after combination treatment with compound 1a-Z51 and chemotherapy drugs (cisplatin or 5-fluorouracil). In summary, the quinazoline analogues of CA-4 represent a promising strategy to achieve a photoswitchable potency for the treatment of cancers, including the development of combination therapies.

EGFR transcription in non-small-cell lung cancer tumours can be revealed in ctDNA by cell-free chromatin immunoprecipitation (cfChIP)

Determination of tumour‐specific transcription based on liquid biopsies possesses a large diagnostic and prognostic potential in non‐small cell lung cancer (NSCLC). Cell‐free DNA (cfDNA) packed in nucleosomes mirrors the histone modification profiles present in the cells of origin. H3 lysine 36 trimethylation (H3K36me3)‐modified nucleosomes are associated with active genes, and therefore, cell‐free chromatin immunoprecipitation (cfChIP) of H3K36me3‐associated cfDNA has the potential to delineate whether transcription of a particular gene is occurring in the cells from which its cfDNA originates. We hypothesized that cfChIP can delineate transcriptional status of genes harbouring somatic cancer mutations and analysed the recurrently observed EGFR‐L858R mutation as an example. In representative NSCLC cell lines, the relationship between wild‐type (WT) and mutated EGFR transcriptional activity and mRNA expression levels was analysed using H3K36me3 ChIP and EGFR mRNA reverse transcription quantitative PCR (RT‐qPCR), respectively. The ChIP analysis showed that both WT and mutated EGFR are transcribed and that mRNA is similarly expressed per EGFR copy. Based on this observation, we proceeded with EGFR cfChIP using blood plasma from NSCLC patients harbouring the EGFR‐L858R mutation. EGFR‐WT fragments can originate from both nontumour cells with no or low EGFR transcription and tumour cells with active EGFR transcription, whereas EGFR‐L858R fragments must specifically originate from tumour cells. H3K36me3 cfChIP followed by droplet digital PCR (ddPCR) revealed significantly higher enrichment of EGFR‐L858R compared to EGFR‐WT fragments. This is in alignment with EGFR‐L858R being actively transcribed in the NSCLC tumour cells. This study is proof‐of‐principle that cfChIP can be used to identify tumour‐specific transcriptional activity of mutated alleles, which can expand the utility of liquid biopsy‐based cfDNA analyses to enhance tumour diagnostics and therapeutics.

Coregulation of pathways in lung cancer patients with EGFR mutation: therapeutic opportunities

Epidermal growth factor receptor (EGFR) mutations in lung adenocarcinoma are a frequent class of driver mutations. Single EGFR tyrosine kinase inhibitor (TKI) provides substantial clinical benefit, but almost nil radiographic complete responses. Patients invariably progress, although survival can reach several years with post-treatment therapies, including EGFR TKIs, chemotherapy or other procedures. Endeavours have been clinically oriented to manage the acquisition of EGFR TKI-resistant mutations; however, basic principles on cancer evolution have not been considered in clinical trials. For years, evidence has displayed rapidly adaptive mechanisms of resistance to selective monotherapy, posing several dilemmas for the practitioner. Strict adherence to non-small cell lung cancer (NSCLC) guidelines is not always practical for addressing the clinical progression that EGFR-mutant lung adenocarcinoma patients suffer. The purpose of this review is to highlight regulatory mechanisms and signalling pathways that cause therapy-induced resistance to EGFR TKIs. It suggests combinatorial therapies that target EGFR, as well as potential mechanisms underlying EGFR-mutant NSCLC, alerting the reader to clinical opportunities that may lead to a deeper and more durable response. Molecular reprogramming contributes to EGFR TKI resistance, and the compiled information is relevant in understanding the development of new combined targeted strategies in EGFR-mutant NSCLC.

EphB4 as a Novel Target for the EGFR-Independent Suppressive Effects of Osimertinib on Cell Cycle Progression in Non-Small Cell Lung Cancer

Osimertinib is the latest generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor used for patients with EGFR-mutated non-small cell lung cancer (NSCLC). We aimed to explore the novel mechanisms of osimertinib by particularly focusing on EGFR-independent effects, which have not been well characterized. We explored the EGFR-independent effects of osimertinib on cell proliferation using NSCLC cell lines, an antibody array analysis, and the association between the action of osimertinib and the ephrin receptor B4 (EphB4). We also studied the clinicopathological significance of EphB4 in 84 lung adenocarcinoma patients. Osimertinib exerted significant inhibitory effects on cell growth and cell cycle progression by promoting the phosphorylation of p53 and p21 and decreasing cyclin D1 expression independently of EGFR. EphB4 was significantly suppressed by osimertinib and promoted cell growth and sensitivity to osimertinib. The EphB4 status in carcinoma cells was positively correlated with tumor size, T factor, and Ki-67 labeling index in all patients and was associated with poor relapse-free survival in EGFR mutation-positive patients. EphB4 is associated with the EGFR-independent suppressive effects of osimertinib on cell cycle and with a poor clinical outcome. Osimertinib can exert significant growth inhibitory effects in EGFR-mutated NSCLC patients with a high EphB4 status.

Connections between prolactin and ovarian cancer

Ovarian cancer (OC) is characterized by a high morbidity and mortality, highlighting a great need for a better understanding of biological mechanisms that affect OC progression and improving its early detection methods. This study investigates effects of prolactin (PRL) on ovarian cancer cells, analyzes PRL receptors (PRLR) in tissue micro arrays and relates PRLR expression to survival of ovarian cancer. A database, composed of transcript profiles from OC, was searched for PRLR expression and results were put in relation to survival. Expression of PRLR in OC tissue sections and OC cell lines SKOV3, OV2008 and OVSAHO was assessed using immunohistochemistry, western blots and quantitative real-time PCR. The biological function of PRLR was evaluated by proliferation, colony formation and wound healing assays. Levels of PRLR mRNA are related to survival; in epithelial OC a high PRLR mRNA expression is related to a shorter survival. Analysis of a tissue micro array consisting of 84 OC showed that 72% were positive for PRLR immuno-staining. PRLR staining tended to be higher in OC of high grade tumors compared to lower grades. PRLR mRNA and protein can further be detected in OC cell lines. Moreover, in vitro treatment with PRL significantly activated the JAK/STAT pathway. PRLR expression is associated with OC survivals. PRL and its receptor may play an onco-modulatory role and promote tumor aggressiveness in OC. Alternatively, increased PRLR levels may form a base for the development of PRLR antagonist or PRLR antagonist-drug conjugate to increase selective uptake of anti-cancer drugs.

Structural basis of the effect of activating mutations on the EGF receptor

Mutations within the kinase domain of the epidermal growth factor receptor (EGFR) are common oncogenic driver events in non-small cell lung cancer. Although the activation of EGFR in normal cells is primarily driven by growth-factor-binding-induced dimerization, mutations on different exons of the kinase domain of the receptor have been found to affect the equilibrium between its active and inactive conformations giving rise to growth-factor-independent kinase activation. Using molecular dynamics simulations combined with enhanced sampling techniques, we compare here the conformational landscape of the monomers and homodimers of the wild-type and mutated forms of EGFR ΔELREA and L858R, as well as of two exon 20 insertions, D770-N771insNPG, and A763-Y764insFQEA. The differences in the conformational energy landscapes are consistent with multiple mechanisms of action including the regulation of the hinge motion, the stabilization of the dimeric interface, and local unfolding transitions. Overall, a combination of different effects is caused by the mutations and leads to the observed aberrant signaling.

Primary metabolic tumor volume from 18F-FDG PET/CT associated with epidermal growth factor receptor mutation in lung adenocarcinoma patients

PURPOSE

To explore the potential parameters from F-FDG PET/CT that might be associated with the epidermal growth factor receptor (EGFR) gene mutation status in lung adenocarcinoma (ADC) patients.

METHODS

Data of the test cohort of 191 patients and the validation cohort of 55 patients with newly diagnosed ADC were retrospectively reviewed. All patients underwent F-FDG PET/CT scans and EGFR mutation tests prior to treatment. The metabolic parameters obtained from F-FDG PET/CT combining with clinical characteristics were analyzed by using univariate and multivariate logistic regression analyses. Then two cohorts were enrolled to validate the predictive model by area under the receiver-operating characteristic curve (AUC), respectively.

RESULTS

EGFR mutation-positive was seen of 33.0% (63/191) and 32.7% (18/55) in two cohorts, respectively. In univariate analysis, female, nonsmokers, metabolic parameters of primary tumor [mean standardized uptake value, metabolic tumor volume (pMTV), and total lesion glycolysis], non-necrosis of primary tumor, and serum tumor markers [carbohydrate antigen 19-9, squamous cell carcinoma antigen, and precursor of gastrin releasing peptide (proGRP)] were significantly relevant with EGFR mutation. In multivariate analysis with adjustment of age and TNM stage, pMTV (<8.13 cm), proGRP (≥38.44 pg/ml) and women were independent significant predictors for EGFR mutation. The AUC for the predictive value of these factors was 0.739 [95% confidence interval (CI) 0.665-0.813] in the cohort of 191 patients and 0.716 (95% CI 0.567-0.865) in the cohort of 55 patients, respectively.

CONCLUSION

Low pMTV (<8.13 cm) was an independent predictor and could be integrated with women and high proGRP (≥38.44 pg/ml) to enhance the discriminability on the EGFR mutation status in ADC patients.

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.

Genotype-determined EGFR-RTK heterodimerization and its effects on drug resistance in lung Cancer treatment revealed by molecular dynamics simulations

BACKGROUND

Epidermal growth factor receptor (EGFR) and its signaling pathways play a vital role in pathogenesis of lung cancer. By disturbing EGFR signaling, mutations of EGFR may lead to progression of cancer or the emergence of resistance to EGFR-targeted drugs.

RESULTS

We investigated the correlation between EGFR mutations and EGFR-receptor tyrosine kinase (RTK) crosstalk in the signaling network, in order to uncover the drug resistance mechanism induced by EGFR mutations. For several EGFR wild type (WT) or mutated proteins, we measured the EGFR-RTK interactions using several computational methods based on molecular dynamics (MD) simulations, including geometrical characterization of the interfaces and conventional estimation of free energy of binding. Geometrical properties, namely the matching rate of atomic solid angles in the interfaces and center-of-mass distances between interacting atoms, were extracted relying on Alpha Shape modeling. For a couple of RTK partners (c-Met, ErbB2 and IGF-1R), results have shown a looser EGFR-RTK crosstalk for the drug-sensitive EGFR mutant while a tighter crosstalk for the drug-resistant mutant. It guarantees the genotype-determined EGFR-RTK crosstalk, and further proposes a potential drug resistance mechanism by amplified EGFR-RTK crosstalk induced by EGFR mutations.

CONCLUSIONS

This study will lead to a deeper understanding of EGFR mutation-induced drug resistance mechanisms and promote the design of innovative drugs.

Chemopreventive effects and anti-tumorigenic mechanisms of 2,6-dimethoxy-1,4-benzoquinone, a constituent of Vitis coignetiae Pulliat (crimson glory vine, known as yamabudo in Japan), toward 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in A/J mice

Previously, we isolated and identified anti-mutagenic and anti-inflammatory components from Vitis coignetiae (crimson glory vine, known as yamabudo in Japan) as 2,6-dimethoxy-1,4-benzoquinone (DBQ), fertaric acid and caftaric acid. We also reported that the oral intake of a partially purified fraction from yamabudo juice (yamabudo-fr) or DBQ affords significant protection against two-stage skin carcinogenesis in mice. In this study, we found that oral intake of yamabudo-fr or DBQ affords significant protection against a tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced mouse model of lung tumorigenesis. Furthermore, we investigated the anti-tumorigenic mechanisms of yamabudo juice and DBQ. NNK is known to be a DNA-methylating and alkylating agent; thus, we investigated the anti-tumorigenic mechanisms of yamabudo juice and DBQ in relation to DNA methylation. Pretreatment with yamabudo-fr or DBQ dose-dependently decreased formation of O⁶-methylguanine and N⁷-methylguanine in DNA of the A549 human lung epithelial-like cell line treated with a methylating agent, 1-methyl-3-nitro-1-nitrosoguanidine. Yamabudo juice and DBQ inhibited the mutagenicity of NNK in the Ames test using Salmonella typhimurium TA1535 but not S. typhimurium YG7108, an alkylguanine DNA alkyltransferase-deficient strain (same as TA1535 but Δada_st::Km^r, Δogt_st::Cm^r). Yamabudo juice and DBQ might accelerate the repair of DNA damage caused by NNK and reduce DNA damage to cells. We also investigated the effects of yamabudo juice and DBQ on signaling pathways in A549 cells. With or without epidermal growth factor stimulation, phosphorylation of Erk1/2, Akt and Stat3 in A549 cells was significantly decreased in the presence of yamabudo juice or DBQ, indicating that yamabudo juice and DBQ suppressed PI3K/AKT, MAPK/ERK and JAK/STAT3 signaling pathways. These results suggest that both initiation and growth/progression steps in carcinogenesis, especially anti-oxidant effects, stimulation of repair of alkyl DNA adducts and suppressed growth signaling pathways are potential anti-tumorigenic targets of yamabudo juice and DBQ in NNK-induced lung tumorigenesis.

Dihydroartemisinin overcomes the resistance to osimertinib in EGFR-mutant non-small-cell lung cancer

Osimertinib, a third-generation EGFR tyrosine kinase inhibitor (TKI), is commonly used to treat EGFR-mutant non-small-cell lung cancer (NSCLC). However, acquired resistance to mutant EGFR (T790M) can evolve following osimertinib treatment. High reactive oxygen species (ROS) levels in lung cancer cells can influence heme levels and have an impact on osimertinib resistance. Here, we found that heme levels were increased in osimertinib resistant EGFR-mutant NSCLC cell lines and plasma heme levels were also elevated in osimertinib-treated EGFR-mutant NSCLC patients. The antimalarial drug dihydroartemisinin (DHA), which has anticancer effects and requires heme, was tested to determine its potential to revert osimertinib resistance. DHA downregulated the expression of heme oxygenase 1 and inhibited cell proliferation in osimertinib-resistant EGFR-mutant NSCLC cells (PC9-GR4-AZD1), which was further enhanced by addition of 5-aminolevulinic acid, protoporphyrin IX and hemin. DHA was synergistic with osimertinib in inhibiting cell proliferation and colony formation of all osimertinib-resistant cell lines tested. Combination treatment with osimertinib and DHA also increased the levels of ROS, downregulated the phosphorylation or protein levels of several RTKs that often are overexpressed in osimertinib-resistant EGFR-mutant NSCLC cells, and inhibited tumor growth without toxicity in a PC9-GR4-AZD1 xenograft mouse model. The results suggest that DHA is able to reverse the resistance to osimertinib in EGFR-mutant NSCLC by elevating ROS level and impair heme metabolism.

EGFR phosphorylates HDAC1 to regulate its expression and anti-apoptotic function

HDAC1 is the prototypical human histone deacetylase (HDAC) enzyme responsible for catalyzing the removal of acetyl group from lysine residues on many substrate proteins. By deacetylating histones and non-histone proteins, HDAC1 has a profound effect on the regulation of gene transcription and many processes related to cell growth and cell death, including cell cycle progression, DNA repair, and apoptosis. Early studies reveal that, like most eukaryotic proteins, the functions and activities of HDAC1 are regulated by post-translational modifications. For example, serine phosphorylation of HDAC1 by protein kinase CK2 promotes HDAC1 deacetylase enzymatic activity and alters its interactions with proteins in corepressor complexes. Here, we describe an alternative signaling pathway by which HDAC1 activities are regulated. Specifically, we discover that EGFR activity promotes the tyrosine phosphorylation of HDAC1, which is necessary for its protein stability. A key EGFR phosphorylation site on HDAC1, Tyr72, mediates HDAC1's anti-apoptotic function. Given that HDAC1 overexpression and EGFR activity are strongly related with tumor progression and cancer cell survival, HDAC1 tyrosine phosphorylation may present a possible target to manipulate HDAC1 protein levels in future potential cancer treatment strategies.

Loss of DLX3 tumor suppressive function promotes progression of SCC through EGFR-ERBB2 pathway

Cutaneous squamous cell carcinoma (cSCC) ranks second in the frequency of all skin cancers. The balance between keratinocyte proliferation and differentiation is disrupted in the pathological development of cSCC. DLX3 is a homeobox transcription factor which plays pivotal roles in embryonic development and epidermal homeostasis. To investigate the impact of DLX3 expression on cSCC prognosis, we carried out clinicopathologic analysis of DLX3 expression which showed statistical correlation between tumors of higher pathologic grade and levels of DLX3 protein expression. Further, Kaplan-Meier survival curve analysis demonstrated that low DLX3 expression correlated with poor patient survival. To model the function of Dlx3 in skin tumorigenesis, a two-stage dimethylbenzanthracene (DMBA)/12-O-tetradecanoylphorbol 13-acetate (TPA) study was performed on mice genetically depleted of Dlx3 in skin epithelium (Dlx3cKO). Dlx3cKO mice developed significantly more tumors, with more rapid tumorigenesis compared to control mice. In Dlx3cKO mice treated only with DMBA, tumors developed after ~16 weeks suggesting that loss of Dlx3 has a tumor promoting effect. Whole transcriptome analysis of tumor and skin tissue from our mouse model revealed spontaneous activation of the EGFR-ERBB2 pathway in the absence of Dlx3. Together, our findings from human and mouse model system support a tumor suppressive function for DLX3 in skin and underscore the efficacy of therapeutic approaches that target EGFR-ERBB2 pathway.

N-glycosylated GPNMB ligand independently activates mutated EGFR signaling and promotes metastasis in NSCLC

Lung cancer is the leading cause of cancer‐related death worldwide. As well as the identified role of epidermal growth factor receptor (EGFR), its association with driver mutations has improved the therapeutics for patients with lung cancer harboring EGFR mutations. These patients usually display shorter overall survival and a higher tendency to develop distant metastasis compared with those carrying the wild‐type EGFR. Nevertheless, the way to control mutated EGFR signaling remains unclear. Here, we performed membrane proteomic analysis to determine potential components that may act with EGFR mutations to promote lung cancer malignancy. Expression of transmembrane glycoprotein non‐metastatic melanoma protein B (GPNMB) was positively correlated with the status of mutated EGFR in non‐small‐cell lung cancer (NSCLC). This protein was not only overexpressed but also highly glycosylated in EGFR‐mutated, especially EGFR‐L858R mutated, NSCLC cells. Further examination showed that GPNMB could activate mutated EGFR without ligand stimulation and could bind to the C‐terminus of EGFR, assist phosphorylation at Y845, turn on downstream STAT3 signaling, and promote cancer metastasis. Moreover, we also found that Asn134 (N134) glycosylation of GPNMB played a crucial role in this ligand‐independent regulation. Depleting N134‐glycosylation on GPNMB could dramatically inhibit binding of GPNMB to mutated EGFR, blocking its downstream signaling, and ultimately inhibiting cancer metastasis in NSCLC. Clarifying the role of N‐glycosylated GPNMB in regulating the ligand‐independent activation of mutated EGFR may soon give new insight into the development of novel therapeutics for NSCLC.

A novel bis-aryl urea compound inhibits tumor proliferation via cathepsin D-associated apoptosis

Supplemental Digital Content is available in the text.

Derivatives of bis-aryl urea have been widely investigated for their various biological activities, such as antiviral, anti-inflammatory and antiproliferative. We evaluated a new chemical entity consisting of bis-aryl urea moiety, N69B, for its anticancer activities and explored their underlying molecular mechanism. The compound inhibited proliferation of multiple types of murine and human cancer cells in vitro, and reduced tumor growth in mouse 4T1 breast tumor model in vivo. Protein microarray analysis revealed and western blot confirmed that the compound significantly increased protein levels of cathepsins, especially cathepsin D, a lysosomal aspartyl protease known to have various pathophysiological functions. Further studies showed that the compound induced tumor cell apoptosis through the Bid/Bax/Cytochrome C/caspase 9/caspase 3 pathway, in which cathepsin D appeared to be a main mediator. Unlike kinase inhibition commonly seen with many other anticancer bis-aryl urea derivatives, this unique mechanism of N69B may suggest potential of the compound as a novel anticancer drug.

Repurposing of glycine transport inhibitors for the treatment of erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is a rare disease in which patients experience severe light sensitivity. It is caused by a deficiency of ferrochelatase (FECH), the last enzyme in heme biosynthesis (HBS). The lack of FECH causes accumulation of its photoreactive substrate protoporphyrin IX (PPIX) in patients' erythrocytes. Here, we explored an approach for the treatment of EPP by decreasing PPIX synthesis using small-molecule inhibitors directed to factors in the HBS pathway. We generated a FECH-knockout clone from K562 erythroleukemia cells, which accumulates PPIX and undergoes oxidative stress upon light exposure. We used these matched cell lines to screen a set of publicly available inhibitors of factors in the HBS pathway. Inhibitors of the glycine transporters GlyT1 and GlyT2 lowered levels of PPIX and markers of oxidative stress selectively in K562^11B4 cells, and in primary erythroid cultures from an EPP patient. Our findings open the door to investigation of glycine transport inhibitors for HBS disorders.

Epidermal Growth Factor Receptor: Key to Selective Intracellular Delivery

Epidermal growth factor receptor (EGFR) is an integral surface protein mediating cellular response to a number of growth factors. Its overexpression and increased activation due to mutations is one of the most common traits of many types of cancer. Development and clinical use of the agents, which block EGFR activation, became a prime example of the personalized targeted medicine. However, despite the obvious success in this area, cancer cure remains unattainable in most cases. Because of that, as well as the result of the search for possible ways to overcome the difficulties of treatment, a huge number of new treatment methods relying on the use of EGFR overexpression and its changes to destroy cancer cells. Modern data on the structure, functioning, and intracellular transport of EGFR, its natural ligands, as well as signaling cascades triggered by the EGFR activation, peculiarities of the EGFR expression and activation in oncological disorders, as well as applied therapeutic approaches aimed at blocking EGFR signaling pathway are summarized and analyzed in this review. Approaches to the targeted delivery of various chemotherapeutic agents, radionuclides, immunotoxins, photosensitizers, as well as the prospects for gene therapy aimed at cancer cells with EGFR overexpression are reviewed in detail. It should be noted that increasing attention is being paid nowadays to the development of multifunctional systems, either carrying several different active agents, or possessing several environment-dependent transport functions. Potentials of the systems based on receptor-mediated endocytosis of EGFR and their possible advantages and limitations are discussed.

Deep sequencing reveals the genomic characteristics of lung adenocarcinoma presenting as ground-glass nodules (GGNs)

Background

The concept of multi-step progression from atypical adenomatous hyperplasia (AAH) to invasive adenocarcinoma (ADC) has been proposed, and ground-glass nodules (GGNs) may play a critical role during the early lung tumorigenesis. We present the first comprehensive description of the genomic architecture of GGNs to unravel the genetic basis of GGN.

Methods

We investigated 30 GGN-like lungs ADC by performing >1,000× whole-exome sequencing (WES) and characterized the genomic variations and evaluate the relationship between the clinicopathologic and molecular characteristics in this disease.

Results

Despite the low somatic mutation burden, GGNs exhibited high intratumor heterogeneity (ITH) characterized by the proportion of subclonal mutations. Different mutagenesis shaped the genomes of GGN during cancer evolution and were mostly featured by molecular clock-like signatures that occur in clonal mutations and defective DNA mismatch signatures that occur in subclonal mutations. Moreover, 10.7–67.1% clonal mutations occurred after whole-genome doubling (WGD), indicating that WGD could be a frequent truncal event in GGNs. Samples with WGD showed higher genomic instability but lower ITH. These GGNs were characterized by recurrent focal copy-number changes that are highly associated with tumorigenesis, with only two genes (EGFR and RBM10) that were recurrently mutated. Additionally, GGNs with different pathological subtypes or computed tomography (CT) features exhibited distinct genetic characteristics. Lepidic predominant or pure GGNs in CT images carried a lower mutation burden and had a relatively stable genome than nonlepidic or mixed GGNs. GGNs with RBM10 mutations tended to accompany a pathologically lepidic pattern, indicating RBM10 may drive the distinct subtype of lung cancer with better prognosis.

Conclusions

These findings facilitated interpreting the genomic characteristics of GGNs, provided insight into the early stages of lung cancer evolution, and possessed potential clinical significance.

β-elemene enhances the antitumor activity of erlotinib by inducing apoptosis through AMPK and MAPK pathways in TKI-resistant H1975 lung cancer cells

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) significantly improve the outcome of non-small-cell lung cancer (NSCLC) patients with EGFR mutations, however, most TKI-treated patients will develop resistance to TKIs. β-elemene, extracted from Curcuma aromatica Salisb., has been widely used to treat various malignant tumors, including TKI-resistant NSCLC, but, the effects and the molecular mechanisms remain unclear. In this study, the NCI-H1975 cell line harboring double mutations L858R/T790M was treated with varying concentrations of β-elemene and/or erlotinib. The effects of β-elemene on cell proliferation, migration, apoptosis, and the expression of relevant proteins of NCI-H1975 cells were evaluated. The results revealed that β‑elemene significantly inhibited the growth, colony formation capacity, wound healing ability of NCI-H1975 cells, and improved the sensitivity of NCI-H1975 cells to erlotinib. Compared with erlotinib alone, β-elemene plus erlotinib significantly promoted the apoptosis of NCI-H1975 cells, accompanied by the down-regulated expression of P-mTOR, P-EGFR, CHOP proteins and up-regulated expression of P-AMPKα and Bax proteins. Taken together, these findings demonstrate that β-elemene suppresses the proliferation and migration of TKI-resistant H1975 cells, and enhances the antitumor activity of erlotinib by inducing apoptosis through AMPK and MAPK pathways in TKI-resistant H1975 lung cancer cells, indicating that β-elemene is a promising anti-cancer therapeutic candidate for TKI-resistant NSCLC.

Clonal Architecture of EGFR Mutation Predicts the Efficacy of EGFR-Tyrosine Kinase Inhibitors in Advanced NSCLC: A Prospective Multicenter Study (NCT03059641)

PURPOSE

Clonal architecture is fundamental for the understanding of cancer biology and therapy; however, multiregional sampling in advanced-stage cancers is not always applicable. This prospective clinical trial was to investigate whether paired tissue and circulating tumor DNA (ctDNA) could describe the clonal architecture of advanced non-small cell lung cancer (NSCLC) and its association with clinical outcome (NCT03059641).

PATIENTS AND METHODS

Paired tumor and plasma ctDNA samples were sequenced by target-capture deep sequencing of 1,021 genes. Clonal dominance analysis was performed on the basis of PyClone.

RESULTS

Overall, 300 treatment-naïve patients with stage IIIB-IV NSCLC were recruited from 14 centers. Of the 94 patients with available ctDNA data for EGFR clonal architecture analysis, 72 (76.6%) showed EGFR as the dominant clone. The median progression-free survival was longer for these patients than for the 22 patients whose EGFR was nondominant clone [11 vs. 10 months; HR, 0.46; 95% confidence interval (CI), 0.24-0.88; P = 0.02]. The difference was more significant if both tissue and ctDNA defined EGFR as dominant clone (n = 43) versus those not (n = 8; 11 vs. 6 months; HR, 0.13; 95% CI, 0.04-0.50; P = 0.003). Moreover, multivariate Cox proportional HR analysis demonstrated EGFR clonal architecture as an independent prognostic indicator of the efficacy of EGFR-tyrosine kinase inhibitors (TKIs).

CONCLUSIONS

Paired tissue and ctDNA could be analyzed for clonal architecture in advanced cancer. EGFR mutations do not always make up a dominant clone in advanced NSCLC, which was associated with the efficacy of EGFR-TKIs in NSCLC.

Performance evaluation of the Biocartis Idylla EGFR Mutation Test using pre-extracted DNA from a cohort of highly characterised mutation positive samples

AIMS

Targeted therapies for non-small cell lung carcinoma (NSCLC) rely on the detection of specific genomic lesions, such as mutations within the epidermal growth factor receptor (EGFR) gene. The Biocartis Idylla platform and single-use EGFR mutation test cartridge is CE-IVD for use with formalin-fixed paraffin embedded (FFPE) tumour material, but can also function off-scope using extracted DNA as input material. This can expand the utility of the platform and potentially conserve valuable tissue.

METHODS

We sought to evaluate the performance of this system to detect known EGFR mutations using extracted DNA at different input levels. 130 next generation sequencing-characterised NSCLC cases possessing EGFR mutations that were theoretically detectable by the Idylla system were selected. Replicate analyses were performed using the Idylla EGFR test with up to three different DNA input levels (20 ng, 50 ng and 250 ng).

RESULTS

Considering only variants within the test manufacturer's specified scope, the Idylla EGFR test generated concordant findings for 90.77% of cases at 20 ng DNA input, 98.46% at 50 ng input and 100% at 250 ng input. Analyses with discordant findings all generated control quantification cycle (CQ) values greater than 23. Very low CQ values were associated with EGFR gene amplification.

CONCLUSIONS

The Idylla EGFR Mutation Test can be used at least as well with pre-extracted DNA than with direct FFPE input. In cases with control CQ >23, reanalysis with an increased DNA input should ideally be undertaken. If this is not possible, the risk of false negative calls may be mitigated by manual review of the quantitative PCR data and/or by reflexing to alternative analysis options.

Discovery of Dosimertinib, a Highly Potent, Selective, and Orally Efficacious Deuterated EGFR Targeting Clinical Candidate for the Treatment of Non-Small-Cell Lung Cancer

Osimertinib is a highly potent and selective third-generation epidermal growth factor receptor (EGFR) inhibitor, which provides excellent clinical benefits and is now a standard-of-care therapy for advanced EGFR mutation-positive non-small-cell lung cancer (NSCLC). However, AZ5104, a primary toxic metabolite of osimertinib, has caused unwanted toxicities. To address this unmet medical need, we initiated an iterative program focusing on structural optimizations of osimertinib and preclinical characterization, leading to the discovery of a highly potent, selective, and orally efficacious deuterated EGFR-targeting clinical candidate, dosimertinib. Preclinical studies revealed that dosimertinib demonstrated robust in vivo antitumor efficacy and favorable PK profiles, but with lower toxicity than osimertinib. These preclinical data support further clinical development of dosimertinib for the treatment of NSCLC. Dosimertinib has received official approval in China to initiate the phase I clinical trial (registration numbers: CXHL2000060 and CXHL2000061).

Metal-free domino amination-Knoevenagel condensation approach to access new coumarins as potent nanomolar inhibitors of VEGFR-2 and EGFR

A metal-free, atom-economy and simple work-up domino amination-Knoevenagel condensation approach to construct new coumarin analogous (4a-f and 8a-e) was described. Further, new formyl (5a,d-f) and nitro (9a,d-f) coumarin derivatives were synthesized via C-N coupling reaction of various cyclic secondary amines and 4-chloro-3-(formyl-/nitro)coumarins (1a,c), respectively. The confirmed compounds were screened for their in vitro anti-proliferative activity against KB-3-1, A549 and PC3 human cancer cell lines using resazurin cellular-based assay. Among them, coumarin derivatives 4e and 8e displayed the best anti-cervical cancer potency (KB-3-1) with IC₅₀ values of 15.5 ± 3.54 and 21 ± 4.24 μM, respectively. Also, 4e showed the most promising cytotoxicity toward A549 with IC₅₀ value of 12.94 ± 1.51 μM. As well, 9d presented a more significant impact of potency against PC3 with IC₅₀ 7.31 ± 0.48 μM. Moreover, 8d manifested selectivity against PC3 (IC₅₀ = 20.16 ± 0.07 μM), while 8e was selective toward KB-3-1 cell line (IC₅₀ = 21 ± 4.24 μM). Matching with docking profile, the enzymatic assay divulged that 8e is a dual potent single-digit nanomolar inhibitor of VEGFR-2 and EGFR with IC₅₀ values of 24.67 nM and 31.6 nM that were almost equipotent to sorafenib (31.08 nM) and erlotinib (26.79 nM), respectively.

Molecular machineries and physiological relevance of ER-mediated membrane contacts

Membrane contact sites (MCSs) are defined as regions where two organelles are closely apposed, and most MCSs associated with each other via protein-protein or protein-lipid interactions. A number of key molecular machinery systems participate in mediating substance exchange and signal transduction, both of which are essential processes in terms of cellular physiology and pathophysiology. The endoplasmic reticulum (ER) is the largest reticulum network within the cell and has extensive communication with other cellular organelles, including the plasma membrane (PM), mitochondria, Golgi, endosomes and lipid droplets (LDs). The contacts and reactions between them are largely mediated by various protein tethers and lipids. Ions, lipids and even proteins can be transported between the ER and neighboring organelles or recruited to the contact site to exert their functions. This review focuses on the key molecules involved in the formation of different contact sites as well as their biological functions.

One-step determination of deletion mutation based on loop-mediated isothermal amplification

Deletion mutation has been proved as the important factor for occurrence and development of disease, especially those with cancer. With the popularity of precision medicine, the individual cancer therapeutic strategy has highlighted the requirement to develop a straightforward and competent strategy for deletion mutation determination. Hence, the present study is dedicated to develop a one-step assay to identify deletion mutation with sequence specificity for clinical practice. Taking advantage of loop-mediated isothermal amplification, an ultrasensitive and rapid deletion mutation determination method is established, which allow as low as 30 copies or 0.1% target variants under strong interferential background can be accurately distinguished in 30 min dispensing with professional operation and complex data interpretation. As a demonstration, the epidermal growth factor receptor p.E746-A750del, a crucial factor for the susceptibility of tyrosine kinase inhibitor in non-small-cell lung cancer treatment, has been accurately identified by this method with both cell lines and real clinical samples. By tailor-made primer set, this method can be extended for other deletion mutants, making it a molecular diagnostic tool and could be readily adapted for cancer diagnosis, therapy and prognosis in point of care diagnostic test scenario.

SHP2 Inhibition Influences Therapeutic Response to Tepotinib in Tumors with MET Alterations

Tepotinib is an oral MET inhibitor approved for metastatic non-small cell lung cancer (NSCLC) harboring MET exon 14 (METex14) skipping mutations. Examining treatment-naive or tepotinib-resistant cells with MET amplification or METex14 skipping mutations identifies other receptor tyrosine kinases (RTKs) that co-exist in cells prior to tepotinib exposure and become more prominent upon tepotinib resistance. In a small cohort of patients with lung cancer with MET genetic alterations treated with tepotinib, gene copy number gains of other RTKs were found at baseline and affected treatment outcome. An Src homology 2 domain-containing phosphatase 2 (SHP2) inhibitor delayed the emergence of tepotinib resistance and synergized with tepotinib in treatment-naive and tepotinib-resistant cells as well as in xenograft models. Alternative signaling pathways potentially diminish the effect of tepotinib monotherapy, and the combination of tepotinib with an SHP2 inhibitor enables the control of tumor growth in cells with MET genetic alterations.

Germline EGFR variants are over-represented in adolescents and young adults (AYA) with adrenocortical carcinoma

Adrenocortical Carcinoma (ACC) is a rare endocrine tumor with poor overall prognosis and 1.5-fold overrepresentation in females. In children, ACC is associated with inherited cancer syndromes with 50-80% of childhood-ACC associated with TP53 germline variants. ACC in adolescents and young adults (AYA) is rarely due to germline TP53, IGF2, PRKAR1A and MEN1 variants. We analyzed exome sequencing data from 21 children (<15y), 32 AYA (15-39y), and 60 adults (>39y) with ACC, and retained all pathogenic, likely pathogenic, and highly prioritized variants of uncertain significance. We engineered a stable lentiviral-mutant ACC cell line, harboring an EGFR variant (p.Asp1080Asn) from a 21-year-old female without germline-TP53-variant and with aggressive ACC. We found that 4.8% of the children (P = 0.004) and 6.2% of AYA (P < 0.0001), all-female participants, harbored germline EGFR variants, compared to only 0.3% of the control group. Expanding our analysis to the RTK-RAS-MAPK pathway, we found that the RTK genes have the highest number of highly prioritized germline variants in these individuals amongst all three arms of this pathway. We showed EGFR mutant cells migrate faster and are characterized by a stem-like phenotype compared to wild type cells. While EGFR inhibitors did not affect the stemness of mutant cells, Sunitinib, a multireceptor tyrosine kinase inhibitor, significantly reduced their stem-like behavior. Our data suggest that EGFR could be a novel underlying germline predisposition factor for ACC, especially in the Childhood-AYA (C-AYA) population. Further clinical validation can improve precision oncology management of this disease, which is known to have limited therapeutic options.

Silencing of LOC389641 impairs cell proliferation and induces autophagy via EGFR/MET signaling in lung adenocarcinoma

High-throughput RNA-sequencing studies of tumor samples have identified a large number of long non-coding RNAs (lncRNAs) which are associated with various types of cancer. LncRNAs play key roles in regulating chromatin dynamics, gene expression, growth, differentiation and development. However, the role of LOC389641 in non-small cell lung cancer (NSCLC) tumorigenesis is not clear. Here, we investigated the expression pattern, roles and mechanism of LOC389641 in lung cancer. LOC389641 expressions in tumor tissues and cell lines were measured by qRT-PCR. Functional studies including colony formation, cell proliferation and invasion were performed in lung cancer cell lines and Western blot was used to exam the protein changes upon siRNA treatment. We found that LOC389641 was highly expressed in lung adenocarcinomas and was associated with poor patient survival. Silencing of LOC389641 reduced colony formation, cell proliferation and invasion, as well as induced autophagy and apoptosis of lung adenocarcinoma cell lines in vitro. Mechanistically, downregulation of LOC389641 was found to decrease EGFR, MET and STAT3 proteins expression in lung cancer cells. LOC389641 is highly expressed and plays an oncogenic role in this type of NSCLC. Because of its specificity, LOC389641 may be a potential biomarker for prognosis and a possible target for lung adenocarcinoma.

Tumor mutation burden as a biomarker for lung cancer patients treated with pemetrexed and cisplatin (the JIPANG-TR)

The JIPANG study is a randomized phase III study of pemetrexed/cisplatin (Pem/Cis) versus vinorelbine/cisplatin (Vnr/Cis) for completely resected stage II-IIIA non-squamous non-small cell lung cancer (Ns-NSCLC). This study did not meet the primary endpoint (recurrence-free survival, RFS) but Pem/Cis had a similar efficacy to Vnr/Cis with a better tolerability. Tumor mutation burden (TMB) is thought to have a predictive value of immune checkpoint inhibitors. However, the relevance of TMB to cytotoxic chemotherapy remains unknown. This exploratory study investigates the relationship between tumor mutation profiles and clinical outcome of Pem/Cis. Formalin-fixed, paraffin-embedded tumor tissues (n = 389) were obtained from the patients. Mutation status of tissue DNA was analyzed by targeted deep sequencing. Epidermal growth factor receptor (EGFR) mutations were detected frequently in Ns-NSCLC (139/374). Patients without any EGFR mutations experienced longer RFS in the Pem/Cis arm versus Vnr/Cis arms. Pem/Cis in patients with high TMB (≥12-16 mut/Mb) tended to have improved survival. In patients with wild-type EGFR, TMB ≥ 12 mut/Mb was significantly associated with improved RFS with Pem/Cis versus Vnr/Cis (not reached vs 52.5 months; hazard ratio (HR) 0.477). It could be proposed that TMB was predictive of RFS benefit with Pem/Cis versus Vnr/Cis in Ns-NSCLC. Further investigation is required to determine whether TMB combined with EGFR mutation status could be used as a predictive biomarker.

ELP-dependent expression of MCL1 promotes resistance to EGFR inhibition in triple-negative breast cancer cells

Targeted therapeutics for cancer generally exploit "oncogene addiction," a phenomenon in which the growth and survival of tumor cells depend on the activity of a particular protein. However, the efficacy of oncogene-targeted therapies varies substantially. For instance, targeting epidermal growth factor receptor (EGFR) signaling is effective in some non-small cell lung cancer (NSCLC) but not in triple-negative breast cancer (TNBC), although these cancers show a similar degree of increase in EGFR activity. Using a genome-wide CRISPR-Cas9 genetic knockout screen, we found that the Elongator (ELP) complex mediates insensitivity to the EGFR inhibitor erlotinib in TNBC cells by promoting the synthesis of the antiapoptotic protein Mcl-1. Depleting ELP proteins promoted apoptotic cell death in an EGFR inhibition-dependent manner. Pharmacological inhibition of Mcl-1 synergized with EGFR inhibition in a panel of genetically diverse TNBC cells. The findings indicate that TNBC "addiction" to EGFR signaling is masked by the ELP complex and that resistance to EGFR inhibitors in TNBC might be overcome by cotargeting Mcl-1.

Detection of the EGFR G719S Mutation in Non-small Cell Lung Cancer Using Droplet Digital PCR

Objectives: The main objectives of the study were (1) to set-up a droplet digital PCR (ddPCR) assay for the non-invasive detection of G719S EGFR mutation in NSCLC patients; (2) to determine the limits of detection of the ddPCR assay for G719S mutation and (3) to compare COBAS® and ddPCR System for G719S quantification in plasma.

Materials and Methods: Blood samples were collected from 22 patients diagnosed with advanced NSCLC. Then, plasma ctDNA was extracted with the Qiagen Circulating Nucleic Acids kit and quantified by QuantiFluor® dsDNA System. The mutational study of EGFR was carried out by digital droplet PCR (ddPCR) with the QX200 Droplet Digital PCR System with specific probes and primers.

Results: We observed the lowest percentage of G719S mutant allele could be detected in a wildtype background was 0.058%. In the specificity analysis, low levels of G719S mutation were detected in healthy volunteers with a peak of 21.65 mutant copies per milliliter of plasma and 6.35 MAFs. In those patients whose tissue biopsy was positive for G719S mutation, mutant alleles could also be detected in plasma using both ddPCR and COBAS® System. Finally, when mutational status was studied using both genotyping techniques, higher mutant copies/ml and higher mutant allele fraction (MAF) correlated with higher Semiquantitative Index obtained by COBAS®.

Conclusions: Although tissue biopsies cannot be replaced due to the large amount of information they provide regarding tumor type and structure, liquid biopsy and ddPCR represents a new promising strategy for genetic analysis of tumors from plasma samples. In the present study, G719S mutation was detected in a highly sensitive manner, allowing its monitorization with a non-invasive technique.

Highly-selective detection of EGFR mutation gene in lung cancer based on surface enhanced Raman spectroscopy and asymmetric PCR

The evaluation of EGFR mutation genes in circulating tumor DNA (ctDNA) in blood sample is key for patients with lung cancer. Surface-enhanced Raman scattering (SERS) has potential for trace detection of DNA or RNA. The detection rate offered by current methods can not meet clinical demand. By combining asymmetric polymerase chain reaction (PCR) and SERS, a highly-selective detection for EGFR mutation genes in lung cancer was developed. Sea-urchin like Au nanoclusters (AuNCs) were synthesized via Ag seed-mediated growth. AuNCs with a diameter of 120 nm were covered with 79 nanopricks (20 nm). Then, EGFR mutation specific molecular beacons (MBs) labeled with Cy3 were coated on the surface of AuNCs. The loading amount of MBs was calculated as 5720 ± 740 on one AuNCs. These AuNCs probes had good efficiency (equilibrium time: 20 minutes) with high sensitivity (detection limit: 5.8 nM), high specificity (capable of single-base mismatch recognition) and good stability against nucleases. Following this, asymmetric PCR was performed to obtain large numbers of single-stranded DNA (ssDNA, E746-A750del). The ssDNA was incubated with the AuNCs probes and tested quantitatively based on the SERS signals of the AuNCs probes. This combined asymmetric PCR-SERS method had a very high detection threshold (4.24 fM). The asymmetric PCR-SERS method was shown to have an overall sensitivity of 75% and specificity of 100% in a further 15 clinical blood samples. This method is proved to be promising for non-invasive and sensitive detection of EGFR mutations in ctDNA.

Gefitinib Represses JAK-STAT Signaling Activated by CRTC1-MAML2 Fusion in Mucoepidermoid Carcinoma Cells

BACKGROUND

Gefitinib is well-known as a tyrosine kinase inhibitor targeting non-smalllung- cancer (NSCLC) containing EGFR mutations. However, its effectiveness in treating mucoepidermoid carcinoma (MEC) without such EGFR mutations suggests additional targets.

OBJECTIVE

The CRTC1-MAML2 (C1-M2) fusion typical for MEC has been proposed to be a gefitinib target.

METHODS

To test this hypothesis, we developed a set of siRNAs to down-regulate C1-M2 expression. RNA-seq and Western blot techniques were applied to analyze the effects of gefitinib and siC1-M2 on the transcriptome of and the phosphorylation of tyrosine kinases in a MEC cell line H292.

RESULTS

Deep-sequencing transcriptome analysis revealed that gefitinib extensively inhibited transcription of genes in JAK-STAT and MAPK/ERK pathways. Both siC1-M2 and gefitinib inhibited the phosphorylation of multiple signaling kinases in these signaling pathways, indicating that gefitinib inhibited JAK-STAT and MAPK/ERK pathways activated by C1-M2 fusion. Moreover, gefitinib inhibition of EGFR and MAPK/ERK was more effective than that of AKT, JAK2 and STATs, and their dependence on C1-M2 could be uncoupled. Taken together, our results suggest that gefitinib simultaneously represses phosphorylation of multiple key signaling proteins which are activated in MEC, in part by C1-M2 fusion. Gefitinib-repressed kinase phosphorylation explains the transcriptional repression of genes in JAK-STAT and MAPK/ERK pathways.

CONCLUSION

These findings provide new insights into the efficacy of gefitinib in treating mucoepidermoid carcinoma, and suggest that a combination of gefitinib and other inhibitors specifically against C1-M2 fusion could be more effective.

Molecular profiling of afatinib-resistant non-small cell lung cancer cells in vivo derived from mice

Non-small-cell lung cancer (NSCLC) is a leading cause of cancer-related death worldwide. NSCLC patients with overexpressed or mutated epidermal growth factor receptor (EGFR) related to disease progression are treated with EGFR-tyrosine kinase inhibitors (EGFR-TKIs). Acquired drug resistance after TKI treatments has been a major focus for development of NSCLC therapies. This study aimed to establish afatinib-resistant cell lines from which afatinib resistance-associated genes are identified and the underlying mechanisms of multiple-TKI resistance in NSCLC can be further investigated. Nude mice bearing subcutaneous NSCLC HCC827 tumors were administered with afatinib at different dose intensities (5-100 mg/kg). We established three HCC827 sublines resistant to afatinib (IC₅₀ > 1 μM) with cross-resistance to gefitinib (IC₅₀ > 5 μM). cDNA microarray revealed several of these sublines shared 27 up- and 13 down-regulated genes. The mRNA expression of selective novel genes - such as transmembrane 4 L six family member 19 (TM4SF19), suppressor of cytokine signaling 2 (SOCS2), and quinolinate phosphoribosyltransferase (QPRT) - are responsive to afatinib treatments only at high concentrations. Furthermore, c-MET amplification and activations of a subset of tyrosine kinase receptors were observed in all three resistant cells. PHA665752, a c-MET inhibitor, remarkably increased the sensitivity of these resistant cells to afatinib (IC₅₀ = 12-123 nM). We established afatinib-resistant lung cancer cell lines and here report genes associated with afatinib resistance in human NSCLC. These cell lines and the identified genes serve as useful investigational tools, prognostic biomarkers of TKI therapies, and promising molecule targets for development of human NSCLC therapeutics.

Expression of AKT and p-AKT protein in lung adenocarcinoma and its correlation with PD-L1 protein and prognosis

Background

The PI3K/AKT/mTOR signaling pathway were significantly associated with EGFR mutation in lung adenocarcinoma (LUAD), but its correlation with PD-L1 protein and prognosis are not clear. The aim of this study was to evaluate the expression of AKT and phosphorylated AKT (p-AKT) in LUAD and its correlation with programmed death ligand-1 (PD-L1); and to analyze the factors affecting LUAD prognosis.

Methods

The expression of AKT, p-AKT, and PD-L1 was examined using immunohistochemistry in LUAD tissues from 110 patients who underwent surgical treatment.

Results

AKT protein expression was examined in 64.5% (71/110) of the LUAD samples, and p-AKT protein expression was examined in 44.5% (49/110) of the LUAD samples. The positive rate of PD-L1 at TC1/2/3 was 38.2% (42/110). AKT and p-AKT expression was significantly associated with epidermal growth factor receptor (EGFR) mutation (P=0.016, P=0.014 respectively). Pearson's correlation analysis indicated a negative correlation of p-AKT with PD-L1 protein (P=0.022). Out of the 62 patients with EGFR mutation, the expression of PD-L1 was negatively correlated with that of p-AKT protein (P=0.032). The expressions of AKT and p-AKT were not associated with prognosis. Multivariate analysis showed that tumor-node-metastasis (TNM) stage (P=0.013) and differentiation (P=0.046) were independent prognostic factors for overall survival.

Conclusions

PI3K/AKT/mTOR in the downstream pathway of EGFR may negatively regulate the expression of PD-L1, which may partly explain why patients with EGFR mutation respond poorly to PD-1/PD-L1 inhibitors.

PLCγ1‑dependent invasion and migration of cells expressing NSCLC‑associated EGFR mutants

The increased tyrosine kinase activity of non‑small cell lung cancer (NSCLC)‑associated epidermal growth factor receptor (EGFR) mutants results in deregulated pathways that contribute to malignant cell survival, tumor progression and metastasis. Previous studies investigating lung cancer‑associated EGFR have focused on the prognostic implications of receptor kinase mutations in patients with NSCLC; however, the role of EGFR mutations in tumor cell invasion and migration remains undetermined. The present study was designed to investigate the role of NSCLC‑associated mutant EGFR‑driven signaling pathways in cell proliferation and invasion. Non‑endogenous EGFR‑expressing 293 cells stably expressing EGFR mutants that are sensitive or resistant to Food and Drug Administration (FDA)‑approved EGFR‑targeted tyrosine kinase inhibitors (TKIs) were used in the present study. The experiments demonstrated an increased phosphorylation of phospholipase (PLC)γ1, c‑Cbl, signal transducer and activator of transcription (Stat), extracellular regulated kinase (Erk)1/2, Akt, Shc and Gab1 proteins in cells expressing a mutant form, rather than the wild‑type receptor. As PLCγ1 is a known regulator of metastatic development, mutant receptor‑mediated PLCγ1 activation was further evaluated. To examine the effects of EGFR and PLCγ1 phosphorylation, the metastatic potential of cells expressing mutants was investigated using wound healing, Transwell cell migration and invasion assays. The inhibition of receptor phosphorylation with the 1st, 2nd and 3rd generation TKIs, gefitinib, afatinib, osimertinib, respectively, reduced PLCγ1 phosphorylation, and reduced the invasive and migratory potential of 293 cells, confirming PLCγ1 as one of the probable downstream effectors of mutant EGFR signaling. However, the PLC inhibitor, U73122, inhibited cell migration and invasion without affecting EGFR signaling and PLCγ1 phosphorylation. Notably, U73122 reduced Akt and Erk1/2 phosphorylation within 25 min of its application; however, 100% cell viability was recorded even after 48 h. Upon further investigation, proliferative signaling pathways remained active at 48 h, in accordance with cell viability. Therefore, the present study concludes that mutant receptor‑mediated PLCγ1 activation may play a significant role in the migration and invasion of NSCLC tumors; however, its regulatory role in tumor cell proliferation warrants further investigation and validation in lung tumor cell lines harboring EGFR mutations.

The PI3Kα inhibitor DFX24 suppresses tumor growth and metastasis in non-small cell lung cancer via ERK inhibition and EPHB6 reactivation

EPHB6 is a metastasis inhibitory gene that is frequently decreased or deficiency in non-small cell lung cancer (NSCLC), which contributed to the subsequent development of distant metastasis. These suggested the possibility that reactivation of EPHB6 might prevent the metastasis of NSCLC. Nevertheless, EPHB6 expression might also promote cancer cell growth and inhibit cell apoptosis by activating Akt and ERK pathway, apart from inhibition of migration and invasion. In the present study, we developed a novel quinazolin-4(3H)-one analog (DFX24) as a potential PI3Kα inhibitor, which inhibited both cell proliferation and metastasis of NSCLC cell lines. Investigation to the molecular mechanisms revealed DFX24 inhibited the cell growth and metastasis via inhibition of PI3Kα and ERK activity, as well as the increase in EPHB6 expression. In addition, DFX24 also induced cell cycle arrest and tumor cell apoptosis by inhibiting PI3K/Akt pathway and activating mitochondria-dependent pathway, respectively. These findings suggested that DFX24 might be considered as a novel drug candidate and may provide a potential therapy for NSCLC.

Molecular Engineering of Ultrasmall Silica Nanoparticle-Drug Conjugates as Lung Cancer Therapeutics

PURPOSE

Small-molecule inhibitors have had a major impact on cancer care. While treatments have demonstrated clinically promising results, they suffer from dose-limiting toxicities and the emergence of refractory disease. Considerable efforts made to address these issues have more recently focused on strategies implementing particle-based probes that improve drug delivery and accumulation at target sites, while reducing off-target effects.

EXPERIMENTAL DESIGN

Ultrasmall (<8 nm) core-shell silica nanoparticles, C' dots, were molecularly engineered to function as multivalent drug delivery vehicles for significantly improving key in vivo biological and therapeutic properties of a prototype epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, gefitinib. Novel surface chemical components were used to conjugate gefitinib-dipeptide drug-linkers and deferoxamine (DFO) chelators for therapeutic delivery and PET imaging labels, respectively.

RESULTS

Gefitinib-bound C' dots (DFO-Gef-C' dots), synthesized using the gefitinib analogue, APdMG, at a range of drug-to-particle ratios (DPR; DPR = 11-56), demonstrated high stability for DPR values≤ 40, bulk renal clearance, and enhanced in vitro cytotoxicity relative to gefitinib (LD₅₀ = 6.21 nmol/L vs. 3 μmol/L, respectively). In human non-small cell lung cancer mice, efficacious Gef-C' dot doses were at least 200-fold lower than that needed for gefitinib (360 nmoles vs. 78 μmoles, respectively), noting fairly equivalent tumor growth inhibition and prolonged survival. Gef-C' dot-treated tumors also exhibited low phosphorylated EFGR levels, with no appreciable wild-type EGFR target inhibition, unlike free drug.

CONCLUSIONS

Results underscore the clinical potential of DFO-Gef-C' dots to effectively manage disease and minimize off-target effects at a fraction of the native drug dose.

Inhibition of DNA‑PK by gefitinib causes synergism between gefitinib and cisplatin in NSCLC

Lung cancer has the highest incidence and mortality rates among the malignant tumor types worldwide. Platinum‑based chemotherapy is the main treatment for advanced non‑small‑cell lung cancer (NSCLC), and epidermal growth factor receptor‑tyrosine kinase inhibitors (EGFR‑TKIs) have greatly improved the survival of patients with EGFR‑sensitive mutations. However, there is no standard therapy for treating patients who are EGFR‑TKI resistant. Combining EGFR‑TKIs and platinum‑based chemotherapy is the most popular strategy in the clinical practice. However, the synergistic mechanism between EGFR‑TKIs and platinum remains unknown. Therefore, the aim of the present study was to determine the synergistic mechanism of gefitinib (an EGFR‑TKI) and cisplatin (a main platinum‑based drug). MTT assay, apoptosis analysis, tumorsphere formation and an orthotropic xenograft mouse model were used to examine the combination effects of gefitinib and cisplatin on NSCLC. Co‑immunoprecipitation and immunofluorescence were used to identify the underlying mechanism. It was found that gefitinib could selectively inhibit EGFR from entering the nucleus, decrease DNA‑PK activity and enhance the cytotoxicity of cisplatin on NSCLC. Collectively, the results suggested that inhibition of DNA‑dependent protein kinase by gefitinib may be due to the synergistic mechanism between gefitinib and cisplatin. Thus, the present study provides a novel insight into potential biomarkers for the selection of combination therapy of gefitinib and cisplatin.

Non-small cell lung cancer patients with ex19del or exon 21 L858R mutation: distinct mechanisms, different efficacies to treatments

With the development of antitumor therapies, different treatment methods including monotherapy and combined therapy have achieved clinical efficacy in advanced epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC) patients. Exon 19 deletion (ex19del) and exon 21 L858R mutation are common sensitive subtypes of EGFR mutation. However, potential distinct mechanisms are found from several dimensions including molecular structures, biological behaviors, concomitant mutations, resistance mechanisms and tumor mutation burdens. More evidence indicates the prognostic difference of EGFR subgroups. This review focused on the progress of potential distinct mechanisms and outcomes in clinical trials of advanced NSCLC patients with ex19del or exon 21 L858R mutation.

Analysis of Single Nucleotide-Mutated Single-Cancer Cells Using the Combined Technologies of Single-Cell Microarray Chips and Peptide Nucleic Acid-DNA Probes

Research into cancer cells that harbor gene mutations relating to anticancer drug-resistance at the single-cell level has focused on the diagnosis of, or treatment for, cancer. Several methods have been reported for detecting gene-mutated cells within a large number of non-mutated cells; however, target single nucleotide-mutated cells within a large number of cell samples, such as cancer tissue, are still difficult to analyze. In this study, a new system is developed to detect and isolate single-cancer cells expressing the T790M-mutated epidermal growth factor receptor (EGFR) mRNA from multiple non-mutated cancer cells by combining single-cell microarray chips and peptide nucleic acid (PNA)-DNA probes. The single-cell microarray chip is made of polystyrene with 62,410 microchambers (31-40 µm diameter). The T790M-mutated lung cancer cell line, NCI-H1975, and non-mutated lung cancer cell line, A549, were successfully separated into single cells in each microchambers on the chip. Only NCI-H1975 cell was stained on the chip with a fluorescein isothiocyanate (FITC)-conjugated PNA probe for specifically detecting T790M mutation. Of the NCI-H1975 cells that spiked into A549 cells, 0–20% were quantitatively analyzed within 1 h, depending on the spike concentration. Therefore, our system could be useful in analyzing cancer tissue that contains a few anticancer drug-resistant cells.

Structure-based virtual screening, pharmacokinetic prediction, molecular dynamics studies for the identification of novel EGFR inhibitors in breast cancer

Breast cancer is one of the most prevalent malignancy cancer types especially affecting women globally. EGFR is a proto onco gene as well as the first identified tyrosine kinase receptor. It plays a dynamic role in many biological tasks such as apoptosis, cell cycle progression, differentiation, development and transcription. Somatic mutation in the EGFR kinase domain derails the normal kinase activity and over expression leads to the progression of cancer especially breast cancer. EGFR is one of the well-known therapeutic targets for breast cancer. In this scenario, we attempt to identify novel potent inhibitors of EGFR. Initially, we performed structure-based virtual screening and identified four potential compounds effective against EGFR. Further, the compounds were subjected to ADME prediction as part of evaluation of the druggability and all the four compounds found to fall under satisfactory range with predicted pharmacokinetic properties. Eventually, the conformational stability of protein-ligand complex was analyzed at different time scale by using Gromacs software. Molecular dynamics simulation run of 20 ns is carried out and results were analyzed using root mean square deviation (RMSD), root mean square fluctuation (RMSF) to signify the stability of protein-igand complex. The stability of the protein-ligand complex is more stable throughout entire simulation. From the results obtained from in silico studies, we propose that these compounds are exceptionally useful for further lead optimization and drug development.Communicated by Ramaswamy H. Sarma.

Putting the brakes on tumorigenesis with snake venom toxins: New molecular insights for cancer drug discovery

Cancer cells exhibit molecular characteristics that confer them different proliferative capacities and survival advantages to adapt to stress conditions, such as deregulation of cellular bioenergetics, genomic instability, ability to promote angiogenesis, invasion, cell dormancy, immune evasion, and cell death resistance. In addition to these hallmarks of cancer, the current cytostatic drugs target the proliferation of malignant cells, being ineffective in metastatic disease. These aspects highlight the need to identify promising therapeutic targets for new generations of anti-cancer drugs. Toxins isolated from snake venoms are a natural source of useful molecular scaffolds to obtain agents with a selective effect on cancer cells. In this article, we discuss the recent advances in the molecular mechanisms of nine classes of snake toxins that suppress the hallmarks of cancer by induction of oxidative phosphorylation dysfunction, reactive oxygen species-dependent DNA damage, blockage of extracellular matrix-integrin signaling, disruption of cytoskeleton network and inhibition of growth factor-dependent signaling. The possible therapeutic implications of toxin-based anti-cancer drug development are also highlighted.

Efficacy of Platinum-Based Adjuvant Chemotherapy on Prognosis of Pathological Stage II/III Lung Adenocarcinoma based on EGFR Mutation Status: A Propensity Score Matching Analysis

OBJECTIVE

This study aimed to retrospectively evaluate the efficacy of platinum-based adjuvant chemotherapy (PBAC) for patients with pathological II/III pulmonary adenocarcinoma after curative resection based on epidermal growth factor receptor (EGFR) mutation status using propensity score matching (PSM) analysis.

METHODS

Among the 304 patients who underwent curative resection of the lung for pathological II/III pulmonary adenocarcinoma from 2002 to 2016 at the Kanagawa Cancer Center, 176 and 128 patients were wild-type EGFR (Wt) and mutant EGFR (Mt), respectively. Seventy-one Wt patients (40.3%) and 60 Mt patients (46.9%) received PBAC. The prognoses of Wt and Mt patients who did and did not receive PBAC were compared using PSM analysis to reduce bias.

RESULTS

The overall survival (OS) of both Wt and Mt patients who received PBAC was significantly better than that of patients who did not receive PBAC before PSM. By multivariate analysis, PBAC was an independent prognostic factor for OS among Wt patients, as were age, carcinoembryonic antigen (CEA) level, pleural invasion, and lymph node metastasis. Although age and CEA level were independent factors for OS among Mt patients, PBAC was not a prognostic factor. After PSM, Wt patients who received PBAC had better OS than those who did not, although Mt patients who did and did not receive PBAC had no difference in OS.

CONCLUSIONS

PBAC was associated with favorable prognosis after curative resection among Wt patients, but not among Mt patients. PBAC might not be necessary for Mt patients with pathological stage II/III pulmonary adenocarcinoma.

Survival prediction model for non-small cell lung cancer based on somatic mutations

BACKGROUND

The 5-year survival rate of non-small cell lung cancer (NSCLC) is only 15%. Screening some combined gene mutations could predict the survival of NSCLC patients and also provide new ideas for the diagnosis and treatment of NSCLC. The present study aimed to identify signature mutations for survival prediction of NSCLC.

METHODS

Clinical and gene mutation information for 949 NSCLC patients was downloaded from TCGA. High frequency mutation and common mutation genes were analyzed based on 1000 cancer related genes. The LASSO-COX model was used to screen gene mutation points and analyze their survival, and then a survival prediction model was established. Fifty NSCLC patients were collected and 1000 targeted genes were enriched by targeted next generation sequencing. The results were used to verify the combination of common mutation genes and the function of the survival model, and then to clarify their clinical significance.

RESULTS

Ten variables were screened out after LASSO-COX analysis, including age, tumor stage, EGFR c.[2,573 T>G], PIK3CA c.[1624G>A], TP53 c.[375G>T], TP53 c.[527G>T], TP53 c.[733G>T], TP53 c.[734G>T], TP53 c.[743G>T], NFE2L2 c.[100C>G]. Except for TP53 c.[743G>T] and NFE2L2 c.[100C>G], the residual six hot spot mutations of EGFR, PIK3CA and TP53 could be regarded as a signature mutations for forecasting the survival time of NSCLC.

CONCLUSIONS

The combination of six hot spot mutations of EGFR, PIK3CA and TP53 is expected to be used for predicting the survival time of NSCLC.

The top 100 cited articles in lung cancer - a bibliometric analysis

Aim of the study

To analyze the 100 most cited lung cancer articles published in biomedical literature in the last 44 years. We pointed out developments in lung cancer and aimed to create convenient access for the researchers of this dynamic field.

Material and methods

We accessed the WoS database (accessed: 15.07.2019) using the keyword “lung cancer” between 1975 and 2019. The top 100 cited articles were analyzed by topic, journal, author, year, institution, level of evidence, adjusted citation index and also the correlations between citation, adjusted citation index, impact factor and length of time since publication.

Results

A total of 240,701 eligible articles were identified and we chose the top 100 articles cited in the field of lung cancer. The mean number of citations for these articles was 1879.82 ±1264.78. The most cited article was (times cited: 7751) a study by Lynch et al. The New England Journal of Medicine (NEJM) made the greatest contribution to the top 100 list with 32 articles, and the most cited article also originated from NEJM. The highest number of citations was seen in 2017 with 18,393 citations while the highest number of publications was seen in 2005 with 12 publications.

Conclusions

Oncology is a developing field and we have seen the evolution in this area through the treatment of lung cancer in recent years. The first 100 articles in our analysis not only reflect the landmark articles with the greatest impact on lung cancer research, but also acknowledge the most productive authors and institutions that have contributed to the list with their articles.