Everolimus synergizes with gefitinib in non-small-cell lung cancer cell lines resistant to epidermal growth factor receptor tyrosine kinase inhibitors

The cell line models to study tyrosine kinase inhibitors in non-small cell lung cancer with mutations in the epidermal growth factor receptor: A scoping review

Non-Small Cell Lung Cancer (NSCLC) represents ∼85% of all lung cancers and ∼15-20% of them are characterized by mutations affecting the Epidermal Growth Factor Receptor (EGFR). For several years now, a class of tyrosine kinase inhibitors was developed, targeting sensitive mutations affecting the EGFR (EGFR-TKIs). To date, the main burden of the TKIs employment is due to the onset of resistance mutations. This scoping review aims to resume the current situation about the cell line models employed for the in vitro evaluation of resistance mechanisms induced by EGFR-TKIs in oncogene-addicted NSCLC. Adenocarcinoma results the most studied NSCLC histotype with the H1650, H1975, HCC827 and PC9 mutated cell lines, while Gefitinib and Osimertinib the most investigated inhibitors. Overall, data collected frame the current advancement of this topic, showing a plethora of approaches pursued to overcome the TKIs resistance, from RNA-mediated strategies to the innovative combination therapies.

Tumor-associated macrophages mediate resistance of EGFR-TKIs in non-small cell lung cancer: mechanisms and prospects

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are the first-line standard treatment for advanced non-small cell lung cancer (NSCLC) with EGFR mutation. However, resistance to EGFR-TKIs is inevitable. Currently, most studies on the mechanism of EGFR-TKIs resistance mainly focus on the spontaneous resistance phenotype of NSCLC cells. Studies have shown that the tumor microenvironment (TME) also mediates EGFR-TKIs resistance in NSCLC. Tumor-associated macrophages (TAMs), one of the central immune cells in the TME of NSCLC, play an essential role in mediating EGFR-TKIs resistance. This study aims to comprehensively review the current mechanisms underlying TAM-mediated resistance to EGFR-TKIs and discuss the potential efficacy of combining EGFR-TKIs with targeted TAMs therapy. Combining EGFR-TKIs with TAMs targeting may improve the prognosis of NSCLC with EGFR mutation to some extent.

The Role of Proteomics and Phosphoproteomics in the Discovery of Therapeutic Targets and Biomarkers in Acquired EGFR-TKI-Resistant Non-Small Cell Lung Cancer

The discovery of potent EGFR-tyrosine kinase inhibitors (EGFR-TKIs) has revolutionized the treatment of EGFR-mutated lung cancer. Despite the fact that EGFR-TKIs have yielded several significant benefits for lung cancer patients, the emergence of resistance to EGFR-TKIs has been a substantial impediment to improving treatment outcomes. Understanding the molecular mechanisms underlying resistance is crucial for the development of new treatments and biomarkers for disease progression. Together with the advancement in proteome and phosphoproteome analysis, a diverse set of key signaling pathways have been successfully identified that provide insight for the discovery of possible therapeutically targeted proteins. In this review, we highlight the proteome and phosphoproteomic analyses of non-small cell lung cancer (NSCLC) as well as the proteome analysis of biofluid specimens that associate with acquired resistance in response to different generations of EGFR-TKI. Furthermore, we present an overview of the targeted proteins and potential drugs that have been tested in clinical studies and discuss the challenges of implementing this discovery in future NSCLC treatment.

Multi-way relation-enhanced hypergraph representation learning for anti-cancer drug synergy prediction

MOTIVATION

Drug combinations have exhibited promise in treating cancers with less toxicity and fewer adverse reactions. However, in vitro screening of synergistic drug combinations is time-consuming and labour-intensive because of the combinatorial explosion. Although a number of computational methods have been developed for predicting synergistic drug combinations, the multi-way relations between drug combinations and cell lines existing in drug synergy data have not been well exploited.

RESULTS

We propose a multi-way relation-enhanced hypergraph representation learning method to predict anti-cancer drug synergy, named HypergraphSynergy. HypergraphSynergy formulates synergistic drug combinations over cancer cell lines as a hypergraph, in which drugs and cell lines are represented by nodes and synergistic drug-drug-cell line triplets are represented by hyperedges, and leverages the biochemical features of drugs and cell lines as node attributes. Then, a hypergraph neural network is designed to learn the embeddings of drugs and cell lines from the hypergraph and predict drug synergy. Moreover, the auxiliary task of reconstructing the similarity networks of drugs and cell lines is considered to enhance the generalization ability of the model. In the computational experiments, HypergraphSynergy outperforms other state-of-the-art synergy prediction methods on two benchmark datasets for both classification and regression tasks, and is applicable to unseen drug combinations or cell lines. The studies revealed that the hypergraph formulation allows us to capture and explain complex multi-way relations of drug combinations and cell lines, and also provides a flexible framework to make the best use of diverse information.

AVAILABILITY AND IMPLEMENTATION

The source data and codes of HypergraphSynergy can be freely downloaded from https://github.com/liuxuan666/HypergraphSynergy.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Exosome-mediated miR-7-5p delivery enhances the anticancer effect of Everolimus via blocking MNK/eIF4E axis in non-small cell lung cancer

Everolimus is a kind of mammalian target of rapamycin (mTOR) inhibitors. Activated mitogen-activated protein kinase interacting kinases/eukaryotic translation initiation factor 4E (MNK/eIF4E) axis plays a crucial role in resistance to Everolimus in non-small cell lung cancer (NSCLC). The eIF4E phosphorylation increased by mTOR inhibitors is mainly mediated by MNKs. However, the mechanisms are poorly understood. Recently, extensive reprogramming of miRNA profiles has also been found after long-term mTOR inhibitor exposure. Our previous studies have confirmed that tumor suppressor miR-7-5p is decreased in A549 cells after treatment with Everolimus. Exactly, MNK1 is the target of miR-7-5p. In this study, we investigated the biological functions and potential molecular mechanisms of miR-7-5p in the NSCLC undergoing treatment with Everolimus. We confirmed that Everolimus targeted mTORC1 inducing NSCLC cells to secrete miR-7-5p-loaded exosomes in Rab27A and Rab27B-dependent manners. Loss of intracellular miR-7-5p induced phosphorylation of MNK/eIF4E axis, but a supplement of extra exosomal miR-7-5p could reverse it. Of note, both low expression of miR-7-5p and elevated MNK1 protein were associated with a poor prognosis of NSCLC. Both endogenous miR-7-5p and exo-miR-7-5p enhanced the therapeutic efficacy of Everolimus by inhibiting the proliferation, migration, and metastasis of NSCLC in vitro and in vivo. The combination of miR-7-5p with Everolimus induced apoptosis to exhibit a synergistic anticancer therapeutic efficacy through dual abrogation of MNK/eIF4E and mTOR in NSCLC. In conclusion, Everolimus decreases the intracellular miR-7-5p by releasing of miR-7-5p loaded exosomes from NSCLC cells in Rab27A and Rab27B dependent manners. Either endogenous miR-7-5p or exo-miR-7-5p combined with Everolimus can enhance the anticancer efficacy by targeting MNK/eIF4E axis and mTOR. Besides, both low levels of miR-7-5p and positive expression of MNK1 act as independent poor prognostic biomarkers for NSCLC. Therefore, restoring miR-7-5p carried by exosome may be a promising novel combined therapeutic strategy with Everolimus for NSCLC.

Metformin Potentiates the Anticancer Effect of Everolimus on Cervical Cancer In Vitro and In Vivo

Simple Summary

Recent studies have shown that metformin combined with clinical chemotherapeutic drugs could cause decreased cell toxicity and attenuate tumor resistance in various types of cancer. The aim of the present study was to elucidate whether combined treatment with metformin and everolimus has a synergistic anticancer effect in human cervical cancer in vitro and in vivo. The results showed that this combined treatment synergistically inhibited the growth of human cervical cancer cell lines and xenografts in nude mice, and induced caspase-dependent apoptosis, promoting sub-G1- and G0/G1-phase arrest and enhancing mtROS production. Combined treatment also synergistically inactivated PI3K/AKT signaling and activated MAPKs signaling in cervical cancer. Our data suggested that metformin potentiates the anticancer effect of everolimus on cervical cancer, and combined treatment provides a novel therapeutic strategy for patients with cervical cancer.

Abstract

Cervical cancer is globally the fourth most common cancer in women. Metformin is a widely used drug for the treatment of type II diabetes and has been shown to possess important anticancer properties in cervical cancer. Everolimus is an mTOR inhibitor and is widely used to treat NETs, RCC, TSC, and breast cancers. The present study investigated the anticancer effects of metformin and everolimus in cervical cancer, when used alone or in combination. CaSki and C33A human cervical cancer cells were treated with different concentrations of everolimus alone or in combination with metformin. Cell viability was assessed using a CCK-8 assay. Cell apoptosis, cell-cycle, and mtROS analyses were conducted using flow cytometry. Target protein levels were analyzed by Western blotting. Related mechanisms were confirmed using appropriate inhibitors (z-VAD-fmk and BIRB796). The in vitro results were further confirmed in a xenograft tumor study. Both metformin and everolimus, when used alone, were moderately effective in inhibiting cell proliferation and inducing cell apoptosis of CaSki and C33A cells. When used in combination, these two drugs synergistically inhibited the growth of human cervical cancer cells and xenografts in nude mice, promoted sub-G1- and G0/G1-phase cell-cycle arrest, and enhanced mtROS production. The protein expressions of PI3K (p110α) and p-AKT were significantly downregulated, while P27, P21, p-p38, p-ERK, and p-JNK were upregulated following combined treatment. These results revealed that metformin potentiates the anticancer effect of everolimus on cervical cancer, and combination treatment with metformin and everolimus provides a novel therapeutic strategy for patients with cervical cancer.

MicroRNAs as Therapeutic Targets for Anticancer Drugs in Lung Cancer Therapy

MicroRNAs (miRNAs) are short, non-coding RNA molecules that regulate gene expression by translational repression or deregulation of messenger RNAs. Accumulating evidence suggests that miRNAs play various roles in the development and progression of lung cancers. Although their precise roles in targeted cancer therapy are currently unclear, miRNAs have been shown to affect the sensitivity of tumors to anticancer drugs. A large number of recent studies have demonstrated that some anticancer drugs exerted antitumor activities by affecting the expression of miRNAs and their targeted genes. These studies have elucidated the specific biological mechanism of drugs in tumor suppression, which provides a new idea or basis for their clinical application. In this review, we summarized the therapeutic mechanisms of drugs in lung cancer therapy through their effects on miRNAs and their targeted genes, which highlights the roles of miRNAs as targets in lung cancer therapy.

mTOR modulates resistance to gemcitabine in lung cancer in an MTORC2 dependent mechanism

BACKGROUND

Lung cancer has a poor prognosis partly due to a lack of response to treatments such as the chemotherapy drug gemcitabine. Combinations of chemotherapy drugs with signal transduction inhibitors may be more effective treatments. In this study we have investigated the impact of targeting the mTOR signalling pathway on the efficacy of gemcitabine in different cancer cell lines.

METHODS

Time-lapse microscopy, immuno-staining, and western blot techniques were used to evaluate the efficacy of applied treatments either in measuring phosphorylation levels of mTOR down-stream targets or in tracking down the fate of targeted cells. Reactive oxygen species and relative levels of protein phosphorylation were also quantified. For comparison between treated groups t-test and analysis of variance test were applied.

RESULTS

Our data showed that mTORC1 has no role in sensitising A549 lung cancer cells to gemcitabine. However, targeting mTORC1/2 with the pharmacological inhibitor torin1 or by over-expressing Deptor, the negative regulator of mTOR signalling, sensitised these cells to gemcitabine. Silencing mTORC2, but not mTORC1, induced apoptosis and significantly improved the apoptosis-inducing effects of gemcitabine. Results also suggest that Rictor is required to maintain cell survival through modulating p38α, ERK1/2, RSK1/2/3 and the transcription factor STAT3. Multiple cell line comparisons revealed that PANC-1 pancreatic cancer cells were also sensitive to mTOR inhibition, but MCF7 breast cancer, MCF10A breast epithelial and H727 lung cancer cell lines were more resistant to the treatment.

CONCLUSIONS

Inhibition of mTORC2 may have benefits in the treatment of gemcitabine resistant cancers, and the genetic background of the cell line may determine its response to mTOR inhibition.

A phase I trial of temsirolimus and erlotinib in patients with refractory solid tumors

PURPOSE

Resistance to treatment with inhibitors of mammalian target of rapamycin (mTOR) is partially mediated by activation of epidermal growth factor receptor (EGFR). We conducted a phase I study to determine the recommended phase II dose (RP2D) and dose-limiting toxicities (DLT) of temsirolimus (mTOR inhibitor) combined with erlotinib (EGFR inhibitor) in patients with refractory solid tumors.

METHODS

Standard "3 + 3" design was used for dose escalation. An expansion cohort at RP2D included only patients with squamous histology or mutations relevant to PI3K or EGFR pathway activation. Patients started daily erlotinib 7 days prior to starting temsirolimus on cycle 1. Intravenous temsirolimus was then administered weekly. Starting dose levels were 15 mg for temsirolimus and 100 mg for erlotinib.

RESULTS

Forty-four patients received treatment on this study (28 in dose escalation and 16 in the expansion cohort). The RP2D was temsirolimus 25 mg IV weekly and erlotinib 100 mg orally daily. Two patients experienced DLTs (G3 dehydration and G4 renal failure). The most common drug-related adverse events (all grades) were rash, mucositis/stomatitis, diarrhea, nausea and fatigue. No complete or partial responses were observed. The median duration on this study was 69 days (range 3-770) for escalation and 88 days (range 25-243) for expansion cohorts. Among 11 response-evaluable patients in the expansion cohort, 9 (82%) had stable disease and 2 (18%) had progressive disease.

CONCLUSION

The combination of temsirolimus and erlotinib at the RP2D was well tolerated, and the regimen resulted in prolonged disease stabilization in selected patients (NCT00770263).

Natural tyrosine kinase inhibitors acting on the epidermal growth factor receptor: Their relevance for cancer therapy

Epidermal growth factor receptor (EGFR), also known as ErbB-1/HER-1, plays a key role in the regulation of the cell proliferation, migration, differentiation, and survival. Since the constitutive activation or overexpression of EGFR is nearly found in various cancers, the applications focused on EGFR are the most widely used in the clinical level, including the therapeutic drugs of targeting EGFR, monoclonal antibodies (mAbs) and tyrosine kinase inhibitors (TKIs).Over the past decades, the compounds from natural sources have been a productive source of novel drugs, especially in both discovery and development of anti-tumor drugs by targeting the EGFR pathways as the TKIs. This work presents a review of the compounds from natural sources as potential EGFR-TKIs involved in the regulation of cancer. Moreover, high-throughput drug screening of EGFR-TKIs from the natural compounds has also been summarized.

PI3K-AKT-mTOR pathway alterations in advanced NSCLC patients after progression on EGFR-TKI and clinical response to EGFR-TKI plus everolimus combination therapy

Background

Several mechanisms including abnormal activation of PI3K-AKT-mTOR pathway have been proved to generate acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC). In this study, we investigated the genomic characteristics of PI3K pathway activated in NSCLC patients after progression on EGFR-TKIs and whether both targeting EGFR and PI3K pathway could overcome resistance.

Methods

A total of 605 NSCLC cases with a history of EGFR TKI treatment were reviewed, in which 324 patients harboring EGFR mutations were confirmed progression on at least one EGFR TKI and finally enrolled. Tumor tissues or blood samples were collected at the onset of TKI progression for next generation sequencing (NGS). Six EGFR mutant patients with co-occurring mutations in PI3K pathway were retrospectively collected to assess the effect of EGFR TKI plus everolimus, a mTOR inhibitor.

Results

Forty-nine (14.9%) patients resistant to EGFR TKIs have at least one genetic variation in PI3K pathway. PIK3CA, PTEN and AKT1 variations were detected in 31 (9.5%), 18 (5.5%) and 3 (0.9%) of patients, respectively. No significant differences were observed in distribution of PI3K pathway alterations among patients with different EGFR mutations (EGFR exon19 deletion mutations/EGFR L858R/uncommon EGFR mutations) and among patients resistant to different EGFR TKIs. For patients treated with everolimus and EGFR-TKI, five (5/6, 83.3%) achieved stable disease (SD) and one (1/6, 16.7%) didn’t receive disease control. The median progression-free survival (PFS) was 2.1 months (95% confidence interval, 1.35–4.3 months, range, 0.9–4.4 months). The most common adverse events were dental ulcer (6/6), rash (1/6).

Conclusions

Our study revealed that PI3K pathway was activated in at least 14.9% in EGFR-TKI resistant patients. EGFR-TKIs plus everolimus showed limited antitumor activity in EGFR mutant NSCLC patients with PI3K pathway aberrations.

Co-targeting EGFR and mTOR with gefitinib and everolimus in triple-negative breast cancer cells

Triple-negative breast cancers (TNBC) are unlikely to respond to hormonal therapies and anti-HER2-targeted therapies. TNBCs overexpress EGFR and exhibit constitutive activation of the PI3K/AKT/mTOR signalling pathway. We hypothesized that simultaneously blocking EGFR and mTOR could be a potential therapeutic strategy for the treatment of TNBC. We examined the antitumour activity of the mTOR inhibitor everolimus combined with the EGFR tyrosine kinase inhibitor gefitinib in TNBC cell with or without activating mutations in the PI3K/AKT/mTOR signalling pathway. We demonstrated that everolimus and gefitinib induced synergistic growth inhibition in the PI3K and PTEN-mutant CAL-51 cell line but not in the PTEN-null HCC-1937 cell line. The antiproliferative effect was associated with synergistic inhibition of mTOR and P70S6K phosphorylation, as well as a significant reduction in 4E-BP1 activation in the CAL-51 cell line. We also showed that combination therapy significantly inhibited cell cycle progression and increased apoptosis in this cell line. Gene and protein expression analysis revealed significant downregulation of cell cycle regulators after exposure to combined treatment. Collectively, these results suggested that dual inhibition of mTOR and EGFR may be an effective treatment for TNBC with activating mutations of PI3K.

Dual Targeting of EGFR and IGF1R in the TNFAIP8 Knockdown Non-Small Cell Lung Cancer Cells

Aberrant regulation of EGFR is common in non-small cell lung carcinomas (NSCLC), and tumor resistance to targeted therapies has been attributed to emergence of other co-occurring oncogenic events, parallel bypass receptor tyrosine kinase pathways including IGF1R, and TNFα-driven adaptive response via NF-κB. TNFAIP8, TNFα-inducible protein 8, is an NF-κB-activated prosurvival and oncogenic molecule. TNFAIP8 expression protects NF-κB-null cells from TNFα-induced cell death by inhibiting caspase-8 activity. Here, we demonstrate that knockdown of TNFAIP8 inhibited EGF and IGF-1-stimulated migration in NSCLC cells. TNFAIP8 knockdown cells showed decreased level of EGFR and increased expression of sorting nexin 1 (SNX1), a key regulator of the EGFR trafficking through the endosomal compartments, and treatment with SNX1 siRNA partially restored EGFR expression in these cells. TNFAIP8 knockdown cells also exhibited downregulation of IGF-1-induced pIGF1R and pAKT, and increased expression of IGF-1-binding protein 3 (IGFBP3), a negative regulator of the IGF-1/IGF1R signaling. Consistently, treatment of TNFAIP8 knockdown cells with IGFBP3 siRNA restored pIGF1R and pAKT levels. TNFAIP8 knockdown cells had enhanced sensitivities to inhibitors of EGFR, PI3K, and AKT. Furthermore, IHC expression of TNFAIP8 was associated with poor prognosis in NSCLC. These findings demonstrate TNFAIP8-mediated regulation of EGFR and IGF1R via SNX1 and IGFBP3, respectively. We posit that TNFAIP8 is a viable, multipronged target downstream of the TNFα/NF-κB axis, and silencing TNFAIP8 may overcome adaptive response in NSCLC. IMPLICATIONS: TNFAIP8 and its effectors SNX1 and IGFBP3 may be exploited to improve the efficacy of molecular-targeted therapies in NSCLC and other cancers.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/17/5/1207/F1.large.jpg.

mTOR signalling: jack-of-all-trades 1

The mechanistic target of rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase that senses and integrates environmental information into cellular regulation and homeostasis. Accumulating evidence has suggested a master role of mTOR signalling in many fundamental aspects of cell biology and organismal development. mTOR deregulation is implicated in a broad range of pathological conditions, including diabetes, cancer, neurodegenerative diseases, myopathies, inflammatory, infectious, and autoimmune conditions. Here, we review recent advances in our knowledge of mTOR signalling in mammalian physiology. We also discuss the impact of mTOR alteration in human diseases and how targeting mTOR function can treat human diseases.

Combination Strategies Using EGFR-TKi in NSCLC Therapy: Learning from the Gap between Pre-Clinical Results and Clinical Outcomes

Although epidermal growth factor receptor (EGFR) inhibitors have been used to treat non-small cell lung cancer (NSCLC) for decades with great success in patients with EGFR mutations, acquired resistance inevitably occurs after long-term exposure. More recently, combination therapy has emerged as a promising strategy to overcome this issue. Several experiments have been carried out to evaluate the synergism of combination therapy both in vitro and in vivo. Additionally, many clinical studies have been carried out to investigate the feasibility of treatment with EGFR-tyrosine kinase inhibitors (TKi) combined with other NSCLC treatments, including radiotherapy, cytotoxic chemotherapies, targeted therapies, and emerging immunotherapies. However, a significant gap still exists when applying pre-clinical results to clinical scenarios, which hinders the development and use of these strategies. This article is a literature review analysing the rationalities and controversies in the transition from pre-clinical investigation to clinical practice associated with various combination strategies. It also highlights clues and challenges regarding future combination therapeutic options in NSCLC treatment.

The anticancer effects of Cucurbitacin I inhibited cell growth of human non‑small cell lung cancer through PI3K/AKT/p70S6K pathway

The present study aimed to identify potential anticancer effects of Cucurbitacin I regulators on cell growth of human non‑small cell lung cancer (NSCLC) and to explore their mechanism. The results indicated that the anticancer effects of Cucurbitacin I markedly attenuated cell proliferation, and induced apoptosis in NSCLC. Furthermore, Cucurbitacin I suppressed phosphatidylinositol‑4,5‑bisphosphate 3‑kinase (PI3K), phosphorylation (p)‑AKT and p‑p70S6K pathway in NSCLC. Then, (PI3K) inhibitor increased anticancer effects of Cucurbitacin I on NSCLC. In conclusion, the present results indicated that Cucurbitacin I inhibited cell growth of human NSCLC through PI3K/AKT/p70S6K signaling pathway.

[Role of Autophagy in the Radiosensitivity of Human Lung Adenocarcinoma A549 Cells]

背景与目的

放射治疗是肺癌最重要的治疗手段之一，然而却因放疗抵抗极易导致肿瘤的复发和转移。放疗可诱导肿瘤细胞自噬发生，最新研究也报道，自噬可能与DNA损伤修复过程相关。本研究旨在探讨通过雷帕霉素上调A549细胞自噬，能否增加细胞放疗敏感性，其过程是否与DNA损伤修复过程相关。

方法

以人肺腺癌A549细胞作为实验对象，实验设对照组(N)、单纯放疗组(IR)、雷帕霉素联合放疗组(R+RAPA)。采用Western blot检测γ-H2AX蛋白质、Rad51蛋白质、Ku70/80蛋白质、p62蛋白质、LC3蛋白质表达；电镜检测自噬体形成；细胞克隆形成实验检测细胞存活分数(survival fraction, SF)值。

结果

与单纯放疗组相比，放疗联合雷帕霉素组自噬活性增加，且Rad51、Ku80蛋白质表达减少，细胞增殖能力下降。

结论

通过雷帕霉素上调自噬可增加肺癌细胞放疗敏感性，其机制可能与抑制DNA损伤修复过程相关。

Genome-wide DNA methylation analyses in lung adenocarcinomas: Association with EGFR, KRAS and TP53 mutation status, gene expression and prognosis

BACKGROUND

DNA methylation alterations are early events in tumorigenesis and important in the regulation of gene expression in cancer cells. Lung cancer patients have in general a poor prognosis, and a deeper insight into the epigenetic landscape in lung adenocarcinoma tumors and its prognostic implications is needed.

RESULTS

We determined whole-genome DNA methylation profiles of 164 fresh frozen lung adenocarcinoma samples and 19 samples of matched normal lung tissue using the Illumina Infinium 450K array. A large number of differentially methylated CpGs in lung adenocarcinoma tissue were identified, and specific methylation profiles were observed in tumors with mutations in the EGFR-, KRAS- or TP53 genes and according to the patients' smoking status. The methylation levels were correlated with gene expression and both positive and negative correlations were seen. Methylation profiles of the tumor samples identified subtypes of tumors with distinct prognosis, including one subtype enriched for TP53 mutant tumors. A prognostic index based on the methylation levels of 33 CpGs was established, and was significantly associated with prognosis in the univariate analysis using an independent cohort of lung adenocarcinoma patients from The Cancer Genome Atlas project. CpGs in the HOX B and HOX C gene clusters were represented in the prognostic signature.

CONCLUSIONS

Methylation differences mirror biologically important features in the etiology of lung adenocarcinomas and influence prognosis.

Therapeutic targeting of replicative immortality

One of the hallmarks of malignant cell populations is the ability to undergo continuous proliferation. This property allows clonal lineages to acquire sequential aberrations that can fuel increasingly autonomous growth, invasiveness, and therapeutic resistance. Innate cellular mechanisms have evolved to regulate replicative potential as a hedge against malignant progression. When activated in the absence of normal terminal differentiation cues, these mechanisms can result in a state of persistent cytostasis. This state, termed “senescence,” can be triggered by intrinsic cellular processes such as telomere dysfunction and oncogene expression, and by exogenous factors such as DNA damaging agents or oxidative environments. Despite differences in upstream signaling, senescence often involves convergent interdependent activation of tumor suppressors p53 and p16/pRB, but can be induced, albeit with reduced sensitivity, when these suppressors are compromised. Doses of conventional genotoxic drugs required to achieve cancer cell senescence are often much lower than doses required to achieve outright cell death. Additional therapies, such as those targeting cyclin dependent kinases or components of the PI3K signaling pathway, may induce senescence specifically in cancer cells by circumventing defects in tumor suppressor pathways or exploiting cancer cells’ heightened requirements for telomerase. Such treatments sufficient to induce cancer cell senescence could provide increased patient survival with fewer and less severe side effects than conventional cytotoxic regimens. This positive aspect is countered by important caveats regarding senescence reversibility, genomic instability, and paracrine effects that may increase heterogeneity and adaptive resistance of surviving cancer cells. Nevertheless, agents that effectively disrupt replicative immortality will likely be valuable components of new combinatorial approaches to cancer therapy.

The reverse effect of X-ray irradiation on acquired gefitinib resistance in non-small cell lung cancer cell line NCI-H1975 in vitro

The clinical efficacy of gefitinib in the treatment of non-small cell lung cancer (NSCLC) with mutations in exon 18, 19 or 21 of epidermal growth factor receptor (EGFR) is limited by the acquired resistance to the drug. To explore whether X-ray irradiation could reverse the acquired gefitinib resistance in NSCLC cell in vitro. We chose a human NSCLC cell line NCI-H1975 to establish acquired gefitinib-resistant cell line named as NCI-H1975/GR. NCI-H1975/GR was irradiated with X-ray and then named as NCI-H1975/GR/XR. In the three cell lines, subsequently cell growth curves and cell population doubling time were calculated by cell proliferation assay, the changes of cell viability were evaluated by trypan blue dye exclusion method and MTT assay, the cell cycle distribution and apoptosis were investigated by flow cytometry, the expressions of E-cadherin and vimentin used to indicate epithelial-mesenchymal transition (EMT) were determined by western blot analysis, the protein expressions in EGFR/KRAS/BRAF transduction pathway were detected by immunocytochemistry, and the mutations of EGFR, KRAS and BRAF were detected by high resolution melting analysis and direct sequencing. We found that the X-ray irradiation enhanced the growth inhibitory effects of gefitinib on the acquired gefitinib-resistant cell line. Of NCI-H1975/GR/XR following gefitinib treatment, the IC50 decreased significantly, the cell proportion of phase G0/G1 was slightly higher, and the apoptosis cell proportion was significantly higher than those of NCI-H1975/GR. In addition, the reversal of EMT being present in NCI-H1975/GR cells was likely appearing in NCI-H1975/GR/XR cells. These results indicated that the acquired gefitinib resistance could be reversed by X-ray irradiation in NSCLC cell line NCI-H1975 harboring both the L858R and T790M mutation in vitro.

Everolimus prolonged survival in transgenic mice with EGFR-driven lung tumors

Everolimus is an orally administered mTOR inhibitor. The effect, and mechanism of action, of everolimus on lung cancers with an epidermal growth factor receptor (EGFR) mutation remain unclear. Four gefitinib-sensitive and -resistant cell lines were used in the present work. Growth inhibition was determined using the MTT assay. Transgenic mice carrying the EGFR L858R mutation were treated with everolimus (10 mg/kg/day), or vehicle alone, from 5 to 20 weeks of age, and were then sacrificed. To evaluate the efficacy of everolimus in prolonging survival, everolimus (10 mg/kg/day) or vehicle was administered from 5 weeks of age. The four cell lines were similarly sensitive to everolimus. Expression of phosphorylated (p) mTOR and pS6 were suppressed upon treatment with everolimus in vitro, whereas the pAKT level increased. The numbers of lung tumors with a long axis exceeding 1mm in the everolimus-treated and control groups were 1.9 ± 0.9 and 9.4 ± 3.2 (t-test, p<0.001), respectively. pS6 was suppressed during eve r olimus treatment. Although apoptosis and autophagy were not induced in everolimus-treated EGFR transgenic mice, angiogenesis was suppressed. The median survival time in the everolimus-treated group (58.0 weeks) was significantly longer than that in the control group (31.2 weeks) (logrank test, p<0.001). These findings suggest that everolimus had an indirect effect on tumor formation by inhibiting angiogenesis and might be effective to treat lung tumors induced by an activating EGFR gene mutation.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

New treatment options for lung adenocarcinoma--in view of molecular background

Lung cancer is the leading cause of cancer related mortality all over the world, and a number of developments have indicated future clinical benefit recently. The development of molecular pathology methods has become increasingly important in the prediction of chemotherapy sensitivity and mutation analysis to identify driver mutations as important targets of new therapeutic agents. The most significant changes in the treatment of NSCLC revealed in new pathologic classification and in the introduction of molecularly targeted therapies, which include monoclonal antibodies and small molecule tyrosine kinase inhibitors. The side effects of these agents are generally better tolerated than those of conventional chemotherapy and show higher efficacy. The most important factor follows: histology subtypes, gene mutation status, patients' selection, drug toxicities and occurence of drug resistance. In the advanced disease, the hope of cure is less than 3%, but improvements in survival have been clearly achieved. Some years ago the median lung cancer survival rate was 10-12 months, now in case of available specific molecular targets, a significant increase in median survival rates to 24-36 months has been achieved. These agents give an opportunity to provide a new standard of care. Therefore testing EGFR mutations and ALK rearrangements in patients with advanced lung adenocarcinoma should be incorporated into routine clinical practice. This review focuses on the rationale for targeted agents and new treatment possibilities in case of advanced lung adenocarcinoma.

New treatment strategy for patients with EGFR-mutant lung cancer

SUMMARY Activating EGFR mutations in non-small-cell lung cancer were discovered in 2004. Patients harboring these mutations, who have been treated with EGFR–tyrosine kinase inhibitor (TKI), are expected to live longer than 2 years. However, lung cancer eventually progresses and the patients die of the disease. Thus, alternative treatments are needed for EGFR-mutated lung cancer. Here, we review the alternative treatments for patients with activating EGFR mutation. Combinations of available EGFR–TKIs (gefitinib or erlotinib) with chemotherapy and newer EGFR–TKIs (second-generation or third-generation EGFR–TKIs) have been developed as treatments for obtaining a more durable response or overcoming the acquired resistance to current EGFR–TKIs. In addition, new drugs other than EGFR–TKIs have also been developed. Their targets include EGFR itself and downstream signals of EGFR pathway, among others. However, these therapies cannot reach clinically striking effects so far. Greater efforts are needed to achieve an increased response, overcome resistance and prolong overall survival.

Molecular Targeted Drugs and Biomarkers in NSCLC, the Evolving Role of Individualized Therapy

Lung cancer first line treatment has been directed from the non-specific cytotoxic doublet chemotherapy to the molecular targeted. The major limitation of the targeted therapies still remains the small number of patients positive to gene mutations. Furthermore, the differentiation between second line and maintenance therapy has not been fully clarified and differs in the clinical practice between cancer centers. The authors present a segregation between maintenance treatment and second line and present a possible definition for the term “maintenance” treatment. In addition, cancer cell evolution induces mutations and therefore either targeted therapies or non-specific chemotherapy drugs in many patients become ineffective. In the present work pathways such as epidermal growth factor, anaplastic lymphoma kinase, met proto-oncogene and PI3K are extensively presented and correlated with current chemotherapy treatment. Future, perspectives for targeted treatment are presented based on the current publications and ongoing clinical trials.

[Efficacy of chemotherapy after EGFR-TKIs resistance in 191 patients with Unknow EGFR gene mutation in advanced lung adenocarcinoma]

背景与目的

晚期肺腺癌患者在使用表皮生长因子受体酪氨酸激酶抑制剂（epidermal growth factor receptor tyrosine kinase inhibitors, EGFR-TKIs）治疗进展后需要接受化疗。本研究旨在探讨EGFR-TKIs耐药后进行化疗的疗效影响因素。

方法

回顾性分析191例晚期肺腺癌患者的临床特征、EGFR-TKIs耐药后第一次化疗的近期疗效及生存时间。

结果

含培美曲塞方案的有效率明显高于不含培美曲塞组，客观缓解率（objective response rate, ORR）分别为9.3%和1.1%（P=0.011），以二线化疗更为明显，ORR分别为14.3%和3.7%（P=0.041）。化疗最好疗效达部分缓解（partial response, PR）者的无进展生存期（progression-free survival, PFS）明显长于未达到PR者（PFS分别为10.1个月和2.3个月，P=0.012）；含铂方案的PFS及总生存期（overall survival, OS）均长于不含铂方案，是独立的预后因素[PFS：相对风险（relative risk, RR）=0.634，95%CI：0.466-0.832，P=0.004；OS：RR=0.666，95%CI：0.460-0.960，P=0.030]，其中TKIs获得性耐药的患者和爆发式进展的患者进行含铂化疗生存获益更多。TKIs耐药的性质（原发或获得性）及TKIs耐药模式（爆发进展、缓慢进展和局部进展）对后续化疗的ORR、PFS及OS均无明显影响。

结论

对于EGFR-TKIs耐药的晚期肺腺癌患者，含培美曲塞方案和含铂方案可能疗效较好。

A phase-1b study of everolimus plus paclitaxel in patients with small-cell lung cancer

BACKGROUND

The mammalian target of rapamycin (mTOR) pathway is dysregulated in small-cell lung cancer (SCLC) and everolimus is an oral mTOR inhibitor.

METHODS

This phase-1b study assessed everolimus safety at the levels of 2.5, 5, or 10 mg once daily in combination with paclitaxel (175 mg m(-2)) once every 3 weeks in previously treated SCLC patients. The primary end point was to determine the maximum tolerated dose of everolimus.

RESULTS

Among 21 enrolled patients, common drug-related adverse events were anaemia, neutropenia, thrombocytopenia, pain, hyperglycemia, and stomatitis. Out of 11 evaluable patients treated with everolimus at the level of 5 mg, 1 patient experienced dose-limiting toxicity (DLT) of grade 4 febrile neutropenia and grade 3 thrombocytopenia. The other two DLTs (grade 4 thrombocytopenia and grade 3 hyperglycemia) occurred in two out of three patients receiving everolimus 10 mg. The overall objective response rate was 28%.

CONCLUSION

Everolimus showed an acceptable safety profile and preliminary antitumour activity at the dose of 5 mg once daily when combined with 3-weekly paclitaxel 175 mg m(-2) in patients with SCLC.

Targeting mTOR to overcome epidermal growth factor receptor tyrosine kinase inhibitor resistance in non-small cell lung cancer cells

AIMS

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have shown dramatic clinical benefits in advanced non-small cell lung cancer (NSCLC); however, resistance remains a serious problem in clinical practice. The present study analyzed mTOR-associated signaling-pathway differences between the EGFR TKI-sensitive and -resistant NSCLC cell lines and investigated the feasibility of targeting mTOR with specific mTOR inhibitor in EGFR TKI resistant NSCLC cells.

METHODS

We selected four different types of EGFR TKI-sensitive and -resistant NSCLC cells: PC9, PC9GR, H1650 and H1975 cells as models to detect mTOR-associated signaling-pathway differences by western blot and Immunoprecipitation and evaluated the antiproliferative effect and cell cycle arrest of ku-0063794 by MTT method and flow cytometry.

RESULTS

In the present study, we observed that mTORC2-associated Akt ser473-FOXO1 signaling pathway in a basal state was highly activated in resistant cells. In vitro mTORC1 and mTORC2 kinase activities assays showed that EGFR TKI-resistant NSCLC cell lines had higher mTORC2 kinase activity, whereas sensitive cells had higher mTORC1 kinase activity in the basal state. The ATP-competitive mTOR inhibitor ku-0063794 showed dramatic antiproliferative effects and G1-cell cycle arrest in both sensitive and resistant cells. Ku-0063794 at the IC50 concentration effectively inhibited both mTOR and p70S6K phosphorylation levels; the latter is an mTORC1 substrate and did not upregulate Akt ser473 phosphorylation which would be induced by rapamycin and resulted in partial inhibition of FOXO1 phosphorylation. We also observed that EGFR TKI-sensitive and -resistant clinical NSCLC tumor specimens had higher total and phosphorylated p70S6K expression levels.

CONCLUSION

Our results indicate mTORC2-associated signaling-pathway was hyperactivated in EGFR TKI-resistant cells and targeting mTOR with specific mTOR inhibitors is likely a good strategy for patients with EGFR mutant NSCLC who develop EGFR TKI resistance; the potential specific roles of mTORC2 in EGFR TKI-resistant NSCLC cells were still unknown and should be further investigated.

Targeted therapies in non-small cell lung carcinoma: what have we achieved so far?

The search for innovative therapeutic agents in non-small cell lung cancer (NSCLC) has witnessed a swift evolution. The number of targeted drugs that can improve patient outcomes with an acceptable safety profile is steadily increasing. In this review, we highlight current drugs that have already been approved or are under evaluation for the treatment of patients with NSCLC, either in monotherapy or combined therapy for both the first- and second-line settings. Experience with drugs targeting the vascular endothelial growth factor and its receptor, as well as the epidermal growth factor receptor is summarized. Moreover, we provide an overview of more novel targets in NSCLC and initial experience with the respective therapeutic agents.

mTOR inhibitors control the growth of EGFR mutant lung cancer even after acquiring resistance by HGF

Resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), gefitinib and erlotinib, is a critical problem in the treatment of EGFR mutant lung cancer. Several mechanisms, including bypass signaling by hepatocyte growth factor (HGF)-triggered Met activation, are implicated as mediators of resistance. The mammalian target of rapamycin (mTOR), is a downstream conduit of EGFR and MET signaling, and is thus considered a therapeutically attractive target in the treatment of various types of cancers. The purpose of this study was to examine whether 2 clinically approved mTOR inhibitors, temsirolimus and everolimus, overcome HGF-dependent resistance to EGFR-TKIs in EGFR mutant lung cancer cells. Both temsirolimus and everolimus inhibited the phosphorylation of p70S6K and 4E-BP1, which are downstream targets of the mTOR pathway, and reduced the viability of EGFR mutant lung cancer cells, PC-9, and HCC827, even in the presence of HGF in vitro. In a xenograft model, temsirolimus suppressed the growth of PC-9 cells overexpressing the HGF-gene; this was associated with suppression of the mTOR signaling pathway and tumor angiogenesis. In contrast, erlotinib did not suppress this signaling pathway or tumor growth. Multiple mechanisms, including the inhibition of vascular endothelial growth factor production by tumor cells and suppression of endothelial cell viability, contribute to the anti-angiogenic effect of temsirolimus. These findings indicate that mTOR inhibitors may be useful for controlling HGF-triggered EGFR-TKI resistance in EGFR mutant lung cancer, and they provide the rationale for clinical trials of mTOR inhibitors in patients stratified by EGFR mutation and HGF expression status.