TP53 mutations in nonsmall cell lung cancer

Effect of the p53α gene on the chemosensitivity of the H1299 human lung adenocarcinoma cell line

To investigate the effects of tumor protein p53 (p53 or TP53) α gene on the chemosensitivity of the H1299 human lung adenocarcinoma cell line, the recombinant vector pEGFP-p53α was constructed. The vector pEGFP-p53α was transfected into the cultured p53-null H1299 cells using Lipofectamine 2000. The G418-resistant cells were then selected. The expression of the p53α gene in these cells was examined using reverse transcription-polymerase chain reaction, and TP53 protein expression was examined using western blot analysis and immunocytochemistry. An MTT assay and colony formation assay were used to analyze the response of the transfected cells to cisplatin (CDDP). DAPI staining was used to determine the level of apoptosis of the transfected cells. The transfected H1299 human lung adenocarcinoma cells stably expressed TP53 protein. The MTT assay demonstrated that the 50% inhibitory concentrations for the H1299, H1299/pEGFP-N₁ and H1299/pEGFP-p53α cells were 28, 24 and 18 µmol/l, respectively. The survival rate of H1299/pEGFP-p53α cells was significantly reduced compared with that of H1299 and H1299/pEGFP-N₁ cells (P<0.05). The colony formation assay and DAPI staining identified that the colony formation rate and the number of apoptotic cells of H1299/pEGFP-p53α were significantly reduced, compared with those of the H1299 and H1299/pEGFP-N₁ cells (P<0.05). Therefor, the present study demonstrated that the transfection of H1299 cells with the p53α gene resulted in an increase in sensitivity to CDDP chemotherapy. The combination of CDDP and gene therapy for H1299 lung adenocarcinoma cell line provides an experimental basis for clinical research.

Nanomaterial-Enabled Cancer Therapy

While cancer remains the major cause of death worldwide, nanomaterial (NM)-based diagnosis and treatment modalities are showing remarkable potential to better tackle clinical oncology by effectively targeting therapeutic agents to tumors. NMs can selectively accumulate in solid tumors, and they can improve the bioavailability and reduce the toxicity of encapsulated cytotoxic agents. Additional noteworthy functions of NMs in cancer treatment include the delivery of contrast agents to image tumor sites, delivery of genetic materials for gene therapy, and co-delivery of multiple agents to achieve combination therapy or simultaneous diagnostic and therapeutic outcomes. Although several NM therapeutics have been successfully translated to clinical applications, the gap between the bench and the bedside remains ominously wide. Tumor heterogeneity and the disparity between pre-clinical and clinical studies have been identified as two of the major translational challenges of NM-based cancer therapies. Herein, we review a handful of recent research studies on the use of NMs in cancer therapy and imaging, with a limited discussion on the consequences of tumor heterogeneity and pre-clinical studies on translational research of NM-based delivery systems and propositions in the literature to overcome these challenges.

Population effect model identifies gene expression predictors of survival outcomes in lung adenocarcinoma for both Caucasian and Asian patients

BACKGROUND

We analyzed and integrated transcriptome data from two large studies of lung adenocarcinomas on distinct populations. Our goal was to investigate the variable gene expression alterations between paired tumor-normal tissues and prospectively identify those alterations that can reliably predict lung disease related outcomes across populations.

METHODS

We developed a mixed model that combined the paired tumor-normal RNA-seq from two populations. Alterations in gene expression common to both populations were detected and validated in two independent DNA microarray datasets. A 10-gene prognosis signature was developed through a l1 penalized regression approach and its prognostic value was evaluated in a third independent microarray cohort.

RESULTS

Deregulation of apoptosis pathways and increased expression of cell cycle pathways were identified in tumors of both Caucasian and Asian lung adenocarcinoma patients. We demonstrate that a 10-gene biomarker panel can predict prognosis of lung adenocarcinoma in both Caucasians and Asians. Compared to low risk groups, high risk groups showed significantly shorter overall survival time (Caucasian patients data: HR = 3.63, p-value = 0.007; Asian patients data: HR = 3.25, p-value = 0.001).

CONCLUSIONS

This study uses a statistical framework to detect DEGs between paired tumor and normal tissues that considers variances among patients and ethnicities, which will aid in understanding the common genes and signalling pathways with the largest effect sizes in ethnically diverse cohorts. We propose multifunctional markers for distinguishing tumor from normal tissue and prognosis for both populations studied.

Co-dependency of PKCδ and K-Ras: inverse association with cytotoxic drug sensitivity in KRAS mutant lung cancer

Recent studies suggest that the presence of a KRAS mutation may be insufficient for defining a clinically homogenous molecular group, as many KRAS mutant tumors lose reliance on K-Ras for survival. Identifying pathways that support K-Ras dependency may define clinically relevant KRAS sub-groups and lead to the identification of new drug targets. We have analyzed a panel of 17 KRAS mutant lung cancer cell lines classified as K-Ras dependent or independent, for co-dependency on PKCδ. We show that functional dependency on K-Ras and PKCδ co-segregate, and that dependency correlates with a more epithelial-like phenotype. Furthermore, we show that the pro-apoptotic and pro-tumorigenic functions of PKCδ also segregate based on K-Ras dependency, as K-Ras independent cells are more sensitive to topoisomerase inhibitors, and depletion of PKCδ in this sub-group suppresses apoptosis through increased activation of ERK. In contrast, K-Ras dependent lung cancer cells are largely insensitive to topoisomerase inhibitors, and depletion of PKCδ can increase apoptosis and decrease activation of ERK in this sub-group. We have previously shown that nuclear translocation of PKCδ is necessary and sufficient for pro-apoptotic signaling. Our current studies show that K-Ras dependent cells are refractive to PKCδ driven apoptosis. Analysis of this sub-group showed increased PKCδ expression and an increase in the nuclear:cytoplasmic ratio of PKCδ. In addition, targeting PKCδ to the nucleus induces apoptosis in K-Ras independent, but not K-Ras dependent NSCLC cells. Our studies provide tools for identification of the subset of patients with KRAS mutant tumors most amenable to targeting of the K-Ras pathway, and identify PKCδ as a potential target in this tumor population. These sub-groups are likely to be of clinical relevance, as high PKCδ expression correlates with increased overall survival and a more epithelial tumor phenotype in patients with KRAS mutant lung adenocarcinomas.

Evaluation of the use of therapeutic peptides for cancer treatment

Cancer along with cardiovascular disease are the main causes of death in the industrialised countries around the World. Conventional cancer treatments are losing their therapeutic uses due to drug resistance, lack of tumour selectivity and solubility and as such there is a need to develop new therapeutic agents. Therapeutic peptides are a promising and a novel approach to treat many diseases including cancer. They have several advantages over proteins or antibodies: as they are (a) easy to synthesise, (b) have a high target specificity and selectivity and (c) have low toxicity. Therapeutic peptides do have some significant drawbacks related to their stability and short half-life. In this review, strategies used to overcome peptide limitations and to enhance their therapeutic effect will be compared. The use of short cell permeable peptides that interfere and inhibit protein-protein interactions will also be evaluated.

LINE-1 hypomethylation is associated to specific clinico-pathological features in Stage I non-small cell lung cancer

OBJECTIVES

We hypothesize that selected genetic and/or epigenetic changes associated with advanced tumours may help identifying early non-small cell lung cancers (NSCLCs) that recur after resection. Among epigenetic changes, long interspersed nuclear element-1 (LINE-1) hypomethylation is seen early during carcinogenesis and may act in concert with genetic alterations to cancer progression. LINE-1 hypomethylation and gene mutations frequently involved in lung cancer, were analysed to evaluate their prognostic role in resected stage I NSCLC.

METHODS

Gene mutations and LINE-1 methylation were analysed in 167 Caucasian patients with stage I NSCLC, namely 100 adenocarcinomas (ADC) and 67 squamous-cell carcinomas (SqCC), using mass-spectrometry and pyrosequencing. We evaluated the correlation between molecular results and clinico-pathological data: age, gender, smoking status, period of surgery, histology, grading, pathological stage, p53 expression, LINE-1 hypomethylation. These variables have been assessed as possible predictors of cancer related survival by regression analysis.

RESULTS

Frequency and spectrum of gene mutations were significantly different in ADCs compared with SqCCs. p53 positivity was more common in SqCC, while EGFR or KRAS mutations were mainly detected in ADC. LINE1 hypomethylation was associated with SqCC histology, p53 immunoreactivity and smoking habit. Stage IB, LINE-1 hypomethylation and PIK3CA mutation independently predicted a worse cancer-related survival. When combined into a scoring system, their prognostic power was strengthened.

CONCLUSIONS

In many stage I NSCLC a mutation pattern of advanced disease was observed. Stage IB, LINE-1 hypomethylation and PIK3CA mutation were associated to poor prognosis. Genetic and epigenetic events occurring in early carcinogenesis may help identifying stage I NSCLC patients who deserve adjuvant therapy.

Influence of microRNAs and Long Non-Coding RNAs in Cancer Chemoresistance

Innate and acquired chemoresistance exhibited by most tumours exposed to conventional chemotherapeutic agents account for the majority of relapse cases in cancer patients. Such chemoresistance phenotypes are of a multi-factorial nature from multiple key molecular players. The discovery of the RNA interference pathway in 1998 and the widespread gene regulatory influences exerted by microRNAs (miRNAs) and other non-coding RNAs have certainly expanded the level of intricacy present for the development of any single physiological phenotype, including cancer chemoresistance. This review article focuses on the latest research efforts in identifying and validating specific key molecular players from the two main families of non-coding RNAs, namely miRNAs and long non-coding RNAs (lncRNAs), having direct or indirect influences in the development of cancer drug resistance properties and how such knowledge can be utilised for novel theranostics in oncology.

Immunohistochemistry for p53 is a useful tool to identify cases of acute myeloid leukemia with myelodysplasia-related changes that are TP53 mutated, have complex karyotype, and have poor prognosis

In this study, we evaluate the expression of p53 in core biopsies with acute myeloid leukemia and correlate the level of expression with acute myeloid leukemia subtype, TP53 mutation status, karyotype, and survival. Of the 143 cases evaluated, 71 fulfilled the WHO 2016 criteria for acute myeloid leukemia with myelodysplasia-related changes, 40 were acute myeloid leukemia-not otherwise specified, 25 were acute myeloid leukemia with recurrent genetic abnormalities, and 7 were therapy-related acute myeloid leukemia. By immunohistochemistry, 17% showed p53 expression in >5% of the cells. Of the 24 cases with >5% p53-positive cells, 17 were acute myeloid leukemia with myelodysplasia-related changes, 5 were acute myeloid leukemia-not otherwise specified, 1 was acute myeloid leukemia with recurrent genetic abormalities, and 1 was therapy-related acute myeloid leukemia. In cases for which data was available, expression of >5% p53-positive cells was significantly associated with genotype (n=67) and/or karyotype (n=130). Among the 115 cases for which clinical follow up was available, the overall survival of cases with p53 expression >15% (Median=102 days) was significantly shorter compared with cases with p53 expression ≤15% (Median=435 days). Within the acute myeloid leukemia with myelodysplasia-related changes group, this association remained significant, with cases with ≤15% p53-positive cells having a median overall survival of 405 days versus 102 days for cases with >15% p53-positive cells. Among acute myeloid leukemia with myelodysplasia-related changes cases with a complex karyotype, the finding of >15% p53-positive cells was significantly associated with worse overall survival. The poor prognosis associated with more than 15% p53-positive cells was independent of age and karyotype. In acute myeloid leukemia with myelodysplasia-related changes, p53 expression may be useful to infer TP53 mutation status, complex karyotype, and/or poor prognosis in situations where other modalities are not readily available.

Role of Autophagy and Apoptosis in Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) constitutes 85% of all lung cancers, and is the leading cause of cancer-related death worldwide. The poor prognosis and resistance to both radiation and chemotherapy warrant further investigation into the molecular mechanisms of NSCLC and the development of new, more efficacious therapeutics. The processes of autophagy and apoptosis, which induce degradation of proteins and organelles or cell death upon cellular stress, are crucial in the pathophysiology of NSCLC. The close interplay between autophagy and apoptosis through shared signaling pathways complicates our understanding of how NSCLC pathophysiology is regulated. The apoptotic effect of autophagy is controversial as both inhibitory and stimulatory effects have been reported in NSCLC. In addition, crosstalk of proteins regulating both autophagy and apoptosis exists. Here, we review the recent advances of the relationship between autophagy and apoptosis in NSCLC, aiming to provide few insights into the discovery of novel pathogenic factors and the development of new cancer therapeutics.

Impact of TP53 Mutations on Outcome in EGFR-Mutated Patients Treated with First-Line Tyrosine Kinase Inhibitors

Purpose: To analyze the impact of TP53 mutations on response to first-line tyrosine kinase inhibitors (TKI) in patients with EGFR-mutated non-small cell lung cancer (NSCLC).Experimental Design: 136 EGFR-mutated NSCLC patients receiving first-line TKIs were analyzed. TP53 mutations were evaluated in 123 patients in relation to disease control rate (DCR), objective response rate (ORR), progression-free survival (PFS), and overall survival (OS).Results:TP53 mutations were observed in 37 (30.1%), 10 (27.0%), 6 (16.2%), 9 (24.3%), and 12 (32.4%) patients in exons 5, 6, 7, and 8, respectively. DCR was 70% in TP53-mutated patients compared with 88% in TP53-wild type (wt) patients [relative risk, RR, of disease progression: 3.17 (95% CI, 1.21-8.48), P = 0.019]. In particular, a 42% DCR was observed in patients with TP53 exon 8 mutation versus 87% in exon 8 wt patients [RR of disease progression 9.6 (2.71-36.63), P < 0.001]. Shorter median PFS and OS were observed in patients with TP53 exon 8 mutations compared with others (4.2 vs. 12.5, P = 0.058, and 16.2 vs. 32.3, P = 0.114, respectively); these differences became significant in the subgroup with EGFR exon 19 deletion (4.2 vs. 16.8, P < 0.001, and 7.6 vs. not reached, P = 0.006, respectively), HR 6.99 (95% CI, 2.34-20.87, P < 0.001) and HR 4.75 (95% CI, 1.38-16.29, P = 0.013), respectively.Conclusions:TP53 mutations, especially exon 8 mutations, reduce responsiveness to TKIs and worsen prognosis in EGFR-mutated NSCLC patients, mainly those carrying exon 19 deletions. Clin Cancer Res; 23(9); 2195-202. ©2016 AACR.

Epigenetic therapy potential of suberoylanilide hydroxamic acid on invasive human non-small cell lung cancer cells

Metastasis is the reason for most cancer death, and a crucial primary step for cancer metastasis is invasion of the surrounding tissue, which may be initiated by some rare tumor cells that escape the heterogeneous primary tumor. In this study, we isolated invasive subpopulations of cancer cells from human non-small cell lung cancer (NSCLC) H460 and H1299 cell lines, and determined the gene expression profiles and the responses of these invasive cancer cells to treatments of ionizing radiation and chemotherapeutic agents. The subpopulation of highly invasive NSCLC cells showed epigenetic signatures of epithelial-mesenchymal transition, cancer cell stemness, increased DNA damage repair and cell survival signaling. We also investigated the epigenetic therapy potential of suberoylanilide hydroxamic acid (SAHA) on invasive cancer cells, and found that SAHA suppresses cancer cell invasiveness and sensitizes cancer cells to treatments of IR and chemotherapeutic agents. Our results provide guidelines for identification of metastatic predictors and for clinical management of NSCLC. This study also suggests a beneficial clinical potential of SAHA as a chemotherapeutic agent for NSCLC patients.

A negative regulation loop of long noncoding RNA HOTAIR and p53 in non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) is one of the leading causes of cancer-related death worldwide, and the 5-year survival rate is still low despite advances in diagnosis and therapeutics. A long noncoding RNA (lncRNA) HOX antisense intergenic RNA (HOTAIR) has been revealed to play important roles in NSCLC carcinogenesis but the detailed mechanisms are still unclear. In the current study, we aimed to investigate the regulation between the lncRNA HOTAIR and p53 in the NSCLC patient samples and cell lines. Our results showed that HOTAIR expression was significantly higher in the cancer tissues than that in the adjacent normal tissue, and was negatively correlated with p53 functionality rather than expression. When p53 was overexpressed in A549 cells, the lncRNA HOTAIR expression was downregulated, and the cell proliferation rate and cell invasion capacity decreased as a consequence. We identified two binding sites of p53 on the promoter region of HOTAIR, where the p53 protein would bind to and suppress the HOTAIR mRNA transcription. Inversely, overexpression of lncRNA HOTAIR inhibited the expression of p53 in A549 cells. Mechanistic studies revealed that HOTAIR modified the promoter of p53 and enhanced histone H3 lysine 27 trimethylation (H3K27me3). These studies identified a specific negative regulation loop of lncRNA HOTAIR and p53 in NSCLC cells, which revealed a new understanding of tumorigenesis in p53 dysfunction NSCLC cells.

Ercc1 Deficiency Promotes Tumorigenesis and Increases Cisplatin Sensitivity in a Tp53 Context-Specific Manner

KRAS-mutant lung adenocarcinoma is among the most common cancer entities and, in advanced stages, typically displays poor prognosis due to acquired resistance against chemotherapy, which is still largely based on cisplatin-containing combination regimens. Mechanisms of cisplatin resistance have been extensively investigated, and ERCC1 has emerged as a key player due to its central role in the repair of cisplatin-induced DNA lesions. However, clinical data have not unequivocally confirmed ERCC1 status as a predictor of the response to cisplatin treatment. Therefore, we employed an autochthonous mouse model of Kras-driven lung adenocarcinoma resembling human lung adenocarcinoma to investigate the role of Ercc1 in the response to cisplatin treatment. Our data show that Ercc1 deficiency in Tp53-deficient murine lung adenocarcinoma induces a more aggressive tumor phenotype that displays enhanced sensitivity to cisplatin treatment. Furthermore, tumors that relapsed after cisplatin treatment in our model develop a robust etoposide sensitivity that is independent of the Ercc1 status and depends solely on previous cisplatin exposure. Our results provide a solid rationale for further investigation of the possibility of preselection of lung adenocarcinoma patients according to the functional ERCC1- and mutational TP53 status, where functionally ERCC1-incompetent patients might benefit from sequential cisplatin and etoposide chemotherapy.

IMPLICATIONS

This study provides a solid rationale for the stratification of lung adenocarcinoma patients according to the functional ERCC1- and mutational TP53 status, where functionally ERCC1-incompetent patients could benefit from sequential cisplatin and etoposide chemotherapy. Mol Cancer Res; 14(11); 1110-23. ©2016 AACR.

Modification of tumor cell exosome content by transfection with wt-p53 and microRNA-125b expressing plasmid DNA and its effect on macrophage polarization

Exosomes are responsible for intercellular communication between tumor cells and others in the tumor microenvironment. These microvesicles promote oncogensis and can support towards metastasis by promoting a pro-tumorogenic environment. Modifying the exosomal content and exosome delivery are emerging novel cancer therapies. However, the clinical translation is limited due to feasibility of isolating and delivery of treated exosomes as well as an associated immune response in patients. In this study, we provide proof-of-concept for a novel treatment approach for manipulating exosomal content by genetic transfection of tumor cells using dual-targeted hyaluronic acid-based nanoparticles. Following transfection with plasmid DNA encoding for wild-type p53 (wt-p53) and microRNA-125b (miR-125b), we evaluate the transgene expression in the SK-LU-1 cells and in the secreted exosomes. Furthermore, along with modulation of wt-p53 and miR-125b expression, we also show that the exosomes (i.e., wt-p53/exo, miR-125b/exo and combination/exo) have a reprogramed global miRNA profile. The miRNAs in the exosomes were mainly related to the activation of genes associated with apoptosis as well as p53 signaling. More importantly, these altered miRNA levels in the exosomes could mediate macrophage repolarization towards a more pro-inflammatory/antitumor M1 phenotype. However, further studies, especially in vivo studies, are warranted to assess the direct influence of such macrophage reprogramming on cancer cells and oncogenesis post-treatment. The current study provides a novel platform enabling the development of therapeutic strategies affecting not only the cancer cells but also the tumor microenvironment by utilizing the 'bystander effect' through genetic transfer with secreted exosomes. Such modification could also support antitumor environment leading to decreased oncogenesis.

Identification of informative genes and pathways using an improved penalized support vector machine with a weighting scheme

Incorporation of pathway knowledge into microarray analysis has brought better biological interpretation of the analysis outcome. However, most pathway data are manually curated without specific biological context. Non-informative genes could be included when the pathway data is used for analysis of context specific data like cancer microarray data. Therefore, efficient identification of informative genes is inevitable. Embedded methods like penalized classifiers have been used for microarray analysis due to their embedded gene selection. This paper proposes an improved penalized support vector machine with absolute t-test weighting scheme to identify informative genes and pathways. Experiments are done on four microarray data sets. The results are compared with previous methods using 10-fold cross validation in terms of accuracy, sensitivity, specificity and F-score. Our method shows consistent improvement over the previous methods and biological validation has been done to elucidate the relation of the selected genes and pathway with the phenotype under study.

The asphericity of the metabolic tumour volume in NSCLC: correlation with histopathology and molecular markers

PURPOSE

Asphericity (ASP) is a tumour shape descriptor based on the PET image. It quantitates the deviation from spherical of the shape of the metabolic tumour volume (MTV). In order to identify its biological correlates, we investigated the relationship between ASP and clinically relevant histopathological and molecular signatures in non-small-cell lung cancer (NSCLC).

METHODS

The study included 83 consecutive patients (18 women, aged 66.4 ± 8.9 years) with newly diagnosed NSCLC in whom PET/CT with ¹⁸F-FDG had been performed prior to therapy. Primary tumour resection specimens and core biopsies were used for basic histopathology and determination of the Ki-67 proliferation index. EGFR status, VEGF, p53 and ALK expression were obtained in a subgroup of 44 patients. The FDG PET images of the primary tumours were delineated using an automatic algorithm based on adaptive thresholding taking into account local background. In addition to ASP, SUVmax, MTV and some further descriptors of shape and intratumour heterogeneity were assessed as semiquantitative PET measures.

RESULTS

SUVmax, MTV and ASP were associated with pathological T stage (Kruskal-Wallis, p = 0.001, p < 0.0005 and p < 0.0005, respectively) and N stage (p = 0.017, p = 0.003 and p = 0.002, respectively). Only ASP was associated with M stage (p = 0.026). SUVmax, MTV and ASP were correlated with Ki-67 index (Spearman's rho = 0.326/p = 0.003, rho = 0.302/p = 0.006 and rho = 0.271/p = 0.015, respectively). The latter correlations were considerably stronger in adenocarcinomas than in squamous cell carcinomas. ASP, but not SUVmax or MTV, showed a tendency for a significant association with the extent of VEGF expression (p = 0.058). In multivariate Cox regression analysis, ASP (p < 0.0005) and the presence of distant metastases (p = 0.023) were significantly associated with progression-free survival. ASP (p = 0.006), the presence of distant metastases (p = 0.010), and Ki-67 index (p = 0.062) were significantly associated with overall survival.

CONCLUSION

The ASP of primary NSCLCs on FDG PET images is associated with tumour dimensions and molecular markers of proliferation and angiogenesis.

Oncogenes: The Passport for Viral Oncolysis Through PKR Inhibition

The transforming properties of oncogenes are derived from gain-of-function mutations, shifting cell signaling from highly regulated homeostatic to an uncontrolled oncogenic state, with the contribution of the inactivating mutations in tumor suppressor genes P53 and RB, leading to tumor resistance to conventional and target-directed therapy. On the other hand, this scenario fulfills two requirements for oncolytic virus infection in tumor cells: inactivation of tumor suppressors and presence of oncoproteins, also the requirements to engage malignancy. Several of these oncogenes have a negative impact on the main interferon antiviral defense, the double-stranded RNA-activated protein kinase (PKR), which helps viruses to spontaneously target tumor cells instead of normal cells. This review is focused on the negative impact of overexpression of oncogenes on conventional and targeted therapy and their positive impact on viral oncolysis due to their ability to inhibit PKR-induced translation blockage, allowing virion release and cell death.

A novel combinatorial strategy using Seliciclib(®) and Belinostat(®) for eradication of non-small cell lung cancer via apoptosis induction and BID activation

With conventional anticancer agents for non-small cell lung cancer (NSCLC) reaching therapeutic ceiling, the novel combination using histone deacetylase inhibitor, PXD101 (Belinostat(®)), and CDK inhibitor, CYC202 (Seliciclib(®)), was investigated as an alternative anticancer strategy. At clinically achievable concentration of CYC202 (15 µM), combination therapy resulted in significant reduction in cell proliferation (IC50 = 3.67 ± 0.80 µM, p < 0.05) compared with PXD101 alone (IC50 = 6.56 ± 0.42 µM) in p53 wild-type A549 cells. Significant increase in apoptosis that occurred independently of cell cycle arrest was observed after concurrent treatment. This result was corroborated by greater formation of cleaved caspase-8, caspase-3 and PARP. Up-regulation of p53 and truncated BID protein levels was seen while Mcl-1 and XIAP protein levels were down-regulated upon combined treatment. Further analysis of apoptotic pathways revealed that caspase inhibitors, but not p53 silencing, significantly abrogated the cytotoxic enhancement. Moreover, the enhanced efficacy of this combination was additionally confirmed in p53 null H2444 cells, suggesting the potential of this combination for treatment of NSCLC that are not amenable to effects of conventional p53-inducing agents.

Multiparameter Lead Optimization to Give an Oral Checkpoint Kinase 1 (CHK1) Inhibitor Clinical Candidate: (R)-5-((4-((Morpholin-2-ylmethyl)amino)-5-(trifluoromethyl)pyridin-2-yl)amino)pyrazine-2-carbonitrile (CCT245737)

Multiparameter optimization of a series of 5-((4-aminopyridin-2-yl)amino)pyrazine-2-carbonitriles resulted in the identification of a potent and selective oral CHK1 preclinical development candidate with in vivo efficacy as a potentiator of deoxyribonucleic acid (DNA) damaging chemotherapy and as a single agent. Cellular mechanism of action assays were used to give an integrated assessment of compound selectivity during optimization resulting in a highly CHK1 selective adenosine triphosphate (ATP) competitive inhibitor. A single substituent vector directed away from the CHK1 kinase active site was unexpectedly found to drive the selective cellular efficacy of the compounds. Both CHK1 potency and off-target human ether-a-go-go-related gene (hERG) ion channel inhibition were dependent on lipophilicity and basicity in this series. Optimization of CHK1 cellular potency and in vivo pharmacokinetic-pharmacodynamic (PK-PD) properties gave a compound with low predicted doses and exposures in humans which mitigated the residual weak in vitro hERG inhibition.

Next-generation sequencing of Chinese stage IV lung cancer patients reveals an association between EGFR mutation status and survival outcome

Large-scale genomic characterization of non-small cell lung cancer (NSCLC) has revealed several putative oncogenic driver mutations that may constitute druggable therapeutic targets. However, there are little data to suggest that such gene alterations have clinical relevance. Over 12 consecutive months, tumor biopsy samples from 80 patients with stage IV NSCLC were analyzed for mutations in selected exons of 508 cancer-related genes using next-generation sequencing. From 85 specimens referred for genomic characterization, 80 (94%) specimens were successfully genotyped, and all had identifiable somatic alterations. Epidermal growth factor receptor (EGFR) and TP53 genes contained the highest frequency of observed mutations (65% and 40%, respectively) in the stage IV NSCLC cases. Notably, patients with EGFR mutations showed a significantly shorter survival time compared with patients expressing wild-type EGFR (p = 0.0053). Moreover, of the 32 patients harboring EGFR mutations, EGFR-L858R mutant patients showed a significantly shorter survival time compared with patients with other EGFR mutations (p = 0.036). In conclusion, tumors from stage IV NSCLC patients harbor characteristic gene alterations, of which EGFR L858R in particular appears to be a poor prognostic factor for overall survival.

Leveraging protein quaternary structure to identify oncogenic driver mutations

BACKGROUND

Identifying key "driver" mutations which are responsible for tumorigenesis is critical in the development of new oncology drugs. Due to multiple pharmacological successes in treating cancers that are caused by such driver mutations, a large body of methods have been developed to differentiate these mutations from the benign "passenger" mutations which occur in the tumor but do not further progress the disease. Under the hypothesis that driver mutations tend to cluster in key regions of the protein, the development of algorithms that identify these clusters has become a critical area of research.

RESULTS

We have developed a novel methodology, QuartPAC (Quaternary Protein Amino acid Clustering), that identifies non-random mutational clustering while utilizing the protein quaternary structure in 3D space. By integrating the spatial information in the Protein Data Bank (PDB) and the mutational data in the Catalogue of Somatic Mutations in Cancer (COSMIC), QuartPAC is able to identify clusters which are otherwise missed in a variety of proteins. The R package is available on Bioconductor at: http://bioconductor.jp/packages/3.1/bioc/html/QuartPAC.html .

CONCLUSION

QuartPAC provides a unique tool to identify mutational clustering while accounting for the complete folded protein quaternary structure.

Mer receptor tyrosine kinase is frequently overexpressed in human non-small cell lung cancer, confirming resistance to erlotinib

Mer is a receptor tyrosine kinase (RTK) with oncogenic properties that is often overexpressed or activated in various malignancies. Using both immunohistochemistry and microarray analyses, we demonstrated that Mer was overexpressed in both tumoral and stromal compartments of about 70% of non-small cell lung cancer (NSCLC) samples relative to surrounding normal lung tissue. This was validated in freshly harvested NSCLC samples; however, no associations were found between Mer expression and patient features. Although Mer overexpression did not render normal lung epithelial cell tumorigenic in vivo, it promoted the in vitro cell proliferation, clonogenic colony formation and migration of normal lung epithelial cells as well as NSCLC cells primarily depending on MAPK and FAK signaling, respectively. Importantly, Mer overexpression induced resistance to erlotinib (EGFR inhibitor) in otherwise erlotinib-sensitive cells. Furthermore, Mer-specific inhibitor rendered erlotinib-resistant cells sensitive to erlotinib. We conclude that Mer enhances malignant phenotype and pharmacological inhibition of Mer overcomes resistance of NSCLC to EGFR-targeted agents.

Combined Effects of Suberoylanilide Hydroxamic Acid and Cisplatin on Radiation Sensitivity and Cancer Cell Invasion in Non-Small Cell Lung Cancer

Lung cancer is a leading cause of cancer-related mortality worldwide, and concurrent chemoradiotherapy has been explored as a therapeutic option. However, the chemotherapeutic agents cannot be administered for most patients at full doses safely with radical doses of thoracic radiation, and further optimizations of the chemotherapy regimen to be given with radiation are needed. In this study, we examined the effects of suberoylanilide hydroxamic acid (SAHA) and cisplatin on DNA damage repairs, and determined the combination effects of SAHA and cisplatin on human non-small cell lung cancer (NSCLC) cells in response to treatment of ionizing radiation (IR), and on tumor growth of lung cancer H460 xenografts receiving radiotherapy. We also investigated the potential differentiation effect of SAHA and its consequences on cancer cell invasion. Our results showed that SAHA and cisplatin compromise distinct DNA damage repair pathways, and treatment with SAHA enhanced synergistic radiosensitization effects of cisplatin in established NSCLC cell lines in a p53-independent manner, and decreased the DNA damage repair capability in cisplatin-treated primary NSCLC tumor tissues in response to IR. SAHA combined with cisplatin also significantly increased inhibitory effect of radiotherapy on tumor growth in the mouse xenograft model. In addition, SAHA can induce differentiation in stem cell-like cancer cell population, reduce tumorigenicity, and decrease invasiveness of human lung cancer cells. In conclusion, our data suggest a potential clinical impact for SAHA as a radiosensitizer and as a part of a chemoradiotherapy regimen for NSCLC. Mol Cancer Ther; 15(5); 842-53. ©2016 AACR.

Complex analysis of the p53 tumor suppressor in lung carcinoma

Lung cancer is the leading cause of cancer-related deaths worldwide. The p53 tumor suppressor is a transcription factor controlling expression of its target genes in response to various stress stimuli. Mutations of the TP53 gene occur very frequently in lung carcinomas and they play an important role in both oncogenic transformation of lung epithelial cells and lung carcinoma progression. We determined the TP53 status in 42 samples of squamous cell lung carcinoma (SQCC) and 56 samples of lung adenocarcinoma (AC) by the functional analysis FASAY and its variant called split assay. Altogether, we detected 64 TP53 mutations in 63 patients and analyzed them by cDNA and gDNA sequencing. The TP53 mutations were found in 76.2% (32/42) of SQCC cases, and 55.4% (31/56) of ACs. Immunoblotting revealed the p53 protein accumulation in 18 samples (42.9%) among SQCC cases and 19 samples (33.9%) among AC cases. Using fluorescence in situ hybridization we detected loss of the TP53-specific 17p13.3 locus in 23 from 41 analyzed SQCC samples (56.1%) and in 20 from 54 analyzed AC samples (37.0%). We did not find any statistically significant differences in overall and disease-free survival in relation to TP53 status.

Biomarkers in early-stage non-small-cell lung cancer: current concepts and future directions

Advances in molecular biology and bioinformatics have resulted in the identification of a number of potential biomarkers that could be relevant in the management of patients with non-small-cell lung cancer (NSCLC). Although there is an increasing amount of literature related to these biomarkers, major issues need to be resolved including validity and reproducibility of results. Additionally, in order to interpret the existing literature accurately, a clear distinction must be made between the prognostic and predictive value of biomarkers. The practical applicability of biomarker discovery for patients with lung cancer includes the identification of patients with early-stage NSCLC who are most likely to benefit from adjuvant therapy. Information gleaned from biomarkers has the potential to help in evaluating the role of targeted therapies including immunotherapy in the neoadjuvant and adjuvant setting. The role of gene signatures and the use of newer platforms such as RNA, methylation, and protein signatures is being explored in patients with early-stage NSCLC. This review focuses on the applications of biomarker discovery in patients with early-stage NSCLC.

TP53 and MDM2 genetic alterations in non-small cell lung cancer: Evaluating their prognostic and predictive value

The p53 pathway has been extensively studied for its role in carcinogenesis. Disruption of the pathway occurs in more than half of all cancers, often leading to a worse prognosis for the patient. In recent years several compounds have been successfully developed to target and restore the p53 pathway, either by blocking the MDM2-p53 interaction, restoring wild type conformation of mutant p53, or exploiting the presence of mutant p53 by blocking DNA damage repair pathways. In this review the known data on the role of p53 on prognosis and response to commonly used chemotherapeutics in non-small cell lung cancer is summarized. The focus is on the presence of genetic alterations in the TP53 or MDM2 gene, p53's main negative regulator. In addition, promising therapeutic options will be discussed in relation to specific alterations in the p53 pathway.

Implementing amplicon-based next generation sequencing in the diagnosis of small cell lung carcinoma metastases

Small cell lung carcinoma (SCLC) is the most aggressive entity of lung cancer. Rapid cancer progression and early formation of systemic metastases drive the deadly outcome of SCLC. Recent advances in identifying oncogenes by cancer whole genome sequencing improved the understanding of SCLC carcinogenesis. However, tumor material is often limited in the clinic. Thus, it is a compulsive issue to improve SCLC diagnostics by combining established immunohistochemistry and next generation sequencing. We implemented amplicon-based next generation deep sequencing in our routine diagnostics pipeline to analyze RB1, TP53, EP300 and CREBBP, frequently mutated in SCLC. Thereby, our pipeline combined routine SCLC histology and identification of somatic mutations. We comprehensively analyzed fifty randomly collected SCLC metastases isolated from trachea and lymph nodes in comparison to specimens derived from primary SCLC. SCLC lymph node metastases showed enhanced proliferation and frequently a collapsed keratin cytoskeleton compared to SCLC metastases isolated from trachea. We identified characteristic synchronous mutations in RB1 and TP53 and non-synchronous CREBBP and EP300 mutations. Our data showed the benefit of implementing deep sequencing into routine diagnostics. We here identify oncogenic drivers and simultaneously gain further insights into SCLC tumor biology.

Role of Exosomal Noncoding RNAs in Lung Carcinogenesis

Lung cancer is the major cause of cancer death worldwide. Novel, recently discovered classes of noncoding RNAs (ncRNAs) have diverse functional and regulatory activities and increasing evidence suggests crucial roles for deregulated ncRNAs in the onset and progression of cancer, including lung cancer. Exosomes are small extracellular membrane vesicles of endocytic origin that are released by many cells and are found in most body fluids. Tumor-derived exosomes mediate tumorigenesis by facilitating tumor growth and metastasis. MicroRNAs (miRNAs) are a subclass of ncRNAs that are present in exosomes. miRNAs are taken up by neighboring or distant cells and modulate various functions of recipient cells. Here, we review exosome-derived ncRNAs with a focus on miRNAs and their role in lung cancer biology.

Expansion of CTCs from early stage lung cancer patients using a microfluidic co-culture model

The potential utility of circulating tumor cells (CTCs) to guide clinical care in oncology patients has gained momentum with emerging micro- and nanotechnologies. Establishing the role of CTCs in tumor progression and metastasis depends both on enumeration and on obtaining sufficient numbers of CTCs for downstream assays. The numbers of CTCs are few in early stages of cancer, limiting detailed molecular characterization. Recent attempts in the literature to culture CTCs isolated from metastatic patients using monoculture have had limited success rates of less than 20%. Herein, we have developed a novel in-situ capture and culture methodology for ex-vivo expansion of CTCs using a three dimensional co-culture model, simulating a tumor microenvironment to support tumor development. We have successfully expanded CTCs isolated from 14 of 19 early stage lung cancer patients. Expanded lung CTCs carried mutations of the TP53 gene identical to those observed in the matched primary tumors. Next-generation sequencing further revealed additional matched mutations between primary tumor and CTCs of cancer-related genes. This strategy sets the stage to further characterize the biology of CTCs derived from patients with early lung cancers, thereby leading to a better understanding of these putative drivers of metastasis.

miR-34c-3p functions as a tumour suppressor by inhibiting eIF4E expression in non-small cell lung cancer

OBJECTIVES

MicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate gene expression and mediate diverse physiological processes. In this study, we investigated functions of miRNA miR-34c-3p in non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

miR-34c-3p expression was evaluated by qPCR. Cell viability was examined by MTT and proliferation by cell cycle analysis. Cell migration and invasion were tested using Transwells with/without Matrigel coating. Western blot analysis was performed for eIF4E, c-Myc, Cyclin D1, survivin and Mcl-1 protein expression.

RESULTS

miR-34c-3p expression was significantly reduced in tissues and serum samples from NSCLC patients and in NSCLC cell lines A549, H460, H23, H157 and H1299. Overexpression of miR-34c-3p in A549 and H157 cells reduced cell proliferation, migration and invasion, whereas transfection with miR-34c-3p inhibitor (miR-34c-3p-in) produced opposite effects. Target analysis using algorithms miRanda, TargetScan and DIANA identified eIF4E as a potential target of miR-34c-3p. Luciferase assay using the eIF4E 3'-UTR reporter carrying a putative miR-34c-3p target sequence revealed eIF4E to be a specific target of miR-34c-3p. Overexpression of miR-34c-3p in NSCLS cell lines led to significant reduction in mRNA and protein levels of eIF4E, whereas inhibition of miR-34c-3p resulted in significant increase in eIf4e protein levels, confirming eIF4E to be a direct target of miR-34c-3p in NSCLS. Overexpression of eIF4E in A549 cells promoted cell proliferation, migration and invasion, which were partially reversed by miR-34c-3p.

CONCLUSION

miR-34c-3p directly targeted eIF4E and reduced miR-34c-3p expression in NSCLC, promoting cell cycle progression, proliferation, migration and invasion.

Identification of Genetic Mutations in Human Lung Cancer by Targeted Sequencing

Lung cancer remains the most prevalent malignancy and the primary cause of cancer-related deaths worldwide. Unique mutations patterns can be found in lung cancer subtypes, in individual cancers, or within a single tumor, and drugs that target these genetic mutations and signal transduction pathways are often beneficial to patients. In this study, we used the Ion Torrent AmpliSeq Cancer Panel to sequence 737 loci from 45 cancer-related genes and oncogenes to identify genetic mutations in 48 formalin-fixed, paraffin-embedded (FFPE) human lung cancer samples from Chinese patients. We found frequent mutations in EGFR, KRAS, PIK3CA, and TP53 genes. Moreover, we observed that a portion of the lung cancer samples harbored two or more mutations in these key genes. This study demonstrates the feasibility of using the Ion Torrent sequencing to efficiently identify genetic mutations in individual tumors for targeted lung cancer therapy.

TP53 transcription factor for the NEDD9/HEF1/Cas-L gene: potential targets in Non-Small Cell Lung Cancer treatment

Lung cancer is a serious public health problem. Although there has been significant progress in chemotherapy, non-small cell lung cancer is still resistant to current treatments, primarily because of the slow rate of cell development. It is thus important to find new molecules directed against targets other than proliferation agents. Considering the high proportion of mutant proteins in tumor cells, and the high rate of mutation of the TP53 gene in all cancers, and in NSCLC in particular, this gene is a perfect target. Certain new molecules have been shown to restore the activity of mutated p53 protein, for example PRIMA-1, which reactivates the His273 mutant p53. In a previous study, we presented triazine A190, a molecule with a cytostatic activity that blocks cells in the G1 phase and induces apoptosis. Here, we show that A190 not only restores mutant p53 activity, but also induces an overexpression of the NEDD9 gene, leading to apoptotic death. These findings might offer hope for the development of new targeted therapies, specific to tumor cells, which spare healthy cells.

Prognostic Value of Malic Enzyme and ATP-Citrate Lyase in Non-Small Cell Lung Cancer of the Young and the Elderly

Background

Lung cancer is the leading cause of death among malignancies worldwide. Understanding its biology is therefore of pivotal importance to improve patient’s prognosis. In contrast to non-neoplastic tissues, cancer cells utilize glucose mainly for production of basic cellular modules ‘(i.e. nucleotides, aminoacids, fatty acids). In cancer, Malic enzyme (ME) and ATP-citrate lyase (ACLY) are key enzymes linking aerobic glycolysis and fatty acid synthesis and may therefore be of biological and prognostic significance in non-small cell lung cancer (NSCLC).

Material and Methods

ME and ACLY expression was analyzed in 258 NSCLC in correlation with clinico-pathological parameters including patient’s survival.

Results

Though, overall expression of both enzymes correlated positively, ACLY was associated with local tumor stage, whereas ME correlated with occurrence of mediastinal lymph node metastases. Young patients overexpressing ACLY and/or ME had a significantly longer overall survival. This proved to be an independent prognostic factor. This contrasts older NSCLC patients, in whom overexpression of ACLY and/or ME appears to predict the opposite.

Conclusion

In NSCLC, ME and ACLY show different enzyme expressions relating to local and mediastinal spread. Most important, we detected an inverse prognostic impact of ACLY and/or ME overexpression in young and elderly patients. It can therefore be expected, that treatment of NSCLC especially, if targeting metabolic pathways, requires different strategies in different age groups.

An ShRNA Based Genetic Screen Identified Sesn2 as a Potential Tumor Suppressor in Lung Cancer via Suppression of Akt-mTOR-p70S6K Signaling

Background

Lung cancer is emerging rapidly as the leading death cause in Chinese cancer patients. The causal factors for Chinese lung cancer development remain largely unclear. Here we employed an shRNA library-based loss-of-function screen in a genome-wide and unbiased manner to interrogate potential tumor suppressor candidates in the immortalized human lung epithelial cell line BEAS-2B.

Methods/Results

Soft agar assays were conducted for screening BEAS-2B cells infected with the retroviral shRNA library with the acquired feature of anchorage-independent growth, large (>0.5mm in diameter) and well—separated colonies were isolated for proliferation. PCRs were performed to amplify the integrated shRNA fragment from individual genomic DNA extracted from each colony, and each PCR product is submitted for DNA sequencing to reveal the integrated shRNA and its target gene. A total of 6 candidate transformation suppressors including INPP4B, Sesn2, TIAR, ACRC, Nup210, LMTK3 were identified. We validated Sesn2 as the candidate of lung cancer tumor suppressor. Knockdown of Sesn2 by an shRNA targeting 3’ UTR of Sesn2 transcript potently stimulated the proliferation and malignant transformation of lung bronchial epithelial cell BEAS-2B via activation of Akt-mTOR-p70S6K signaling, whereas ectopic expression of Sens2 re-suppressed the malignant transformation elicited by the Sesn2 shRNA. Moreover, knockdown of Sesn2 in BEAS-2B cells promoted the BEAS-2B cell-transplanted xenograft tumor growth in nude mice. Lastly, DNA sequencing indicated mutations of Sesn2 gene are rare, the protein levels of Sesn2 of 77 Chinese lung cancer patients varies greatly compared to their adjacent normal tissues, and the low expression level of Sesn2 associates with the poor survival in these examined patients by Kaplan Meier analysis.

Conclusions

Our shRNA-based screen has demonstrated Sesn2 is a potential tumor suppressor in lung epithelial cells. The expression level of Sesn2 may serve as a prognostic marker for Chinese lung cancer patients in the clinic.

Impact of metformin use on survival in locally-advanced, inoperable non-small cell lung cancer treated with definitive chemoradiation

BACKGROUND

We investigated survival outcomes in diabetic patients with non-small cell lung cancer (NSCLC) treated with concurrent metformin and definitive chemoradiation.

METHODS

This single-institution, retrospective cohort study included 166 patients with NSCLC who were treated definitively with chemoradiation between 1999 and 2013. Of 40 patients who had type II diabetes, 20 (50%) were on metformin, and 20 (50%) were not on metformin. The primary outcome was overall survival (OS), and secondary outcomes included progression-free survival (PFS), locoregional recurrence-free survival (LRRFS) and distant metastasis-free survival (DMFS). Kaplan Meier method and log-rank test were performed in survival analysis. Cox regression was utilized in univariate analysis of potential confounders.

RESULTS

Median follow-up was 17.0 months. Compared with non-diabetic patients, diabetic patients on metformin demonstrated similar OS (16.3 vs. 14.3 mo, P=0.23), PFS (11.6 vs. 9.7 mo, P=0.26), LRRFS (14.1 vs. 11.9 mo, P=0.78), and DMFS (13.4 vs. 10.0 mo, P=0.69). Compared with diabetic patients not on metformin, diabetic patients on metformin also exhibited similar OS (14.3 vs. 19.2 mo, P=0.18), PFS (19.7 vs. 10.1 mo, P=0.38), LRRFS (11.9 vs. 15.5 mo, P=0.69), and DMFS (10.0 vs. 17.4 mo, P=0.12). Identified negative prognostic factors on included squamous cell histology, lower performance status, higher T stage, and non-caucasian ethnicity.

CONCLUSIONS

No statistically significant differences in survival or patterns of failure were found among the three cohorts in this small set of patients. No statistically significant differences in survival or patterns of failure were found between the three cohorts in this small set of patients. Though it is possible that metformin use may in fact have no effect on survival in NSCLC patients treated with definitive RT, larger-scale retrospective and prospective studies are implicated for clarification.

Lysyl hydroxylase 2 induces a collagen cross-link switch in tumor stroma

Epithelial tumor metastasis is preceded by an accumulation of collagen cross-links that heighten stromal stiffness and stimulate the invasive properties of tumor cells. However, the biochemical nature of collagen cross-links in cancer is still unclear. Here, we postulated that epithelial tumorigenesis is accompanied by changes in the biochemical type of collagen cross-links. Utilizing resected human lung cancer tissues and a p21CIP1/WAF1-deficient, K-rasG12D-expressing murine metastatic lung cancer model, we showed that, relative to normal lung tissues, tumor stroma contains higher levels of hydroxylysine aldehyde-derived collagen cross-links (HLCCs) and lower levels of lysine aldehyde-derived cross-links (LCCs), which are the predominant types of collagen cross-links in skeletal tissues and soft tissues, respectively. Gain- and loss-of-function studies in tumor cells showed that lysyl hydroxylase 2 (LH2), which hydroxylates telopeptidyl lysine residues on collagen, shifted the tumor stroma toward a high-HLCC, low-LCC state, increased tumor stiffness, and enhanced tumor cell invasion and metastasis. Together, our data indicate that LH2 enhances the metastatic properties of tumor cells and functions as a regulatory switch that controls the relative abundance of biochemically distinct types of collagen cross-links in the tumor stroma.

SLC25A1, or CIC, is a novel transcriptional target of mutant p53 and a negative tumor prognostic marker

Mutations of the p53 gene hallmark many human cancers. Several p53 mutant proteins acquire the capability to promote cancer progression and metastasis, a phenomenon defined as Gain of Oncogenic Function (GOF). The downstream targets by which GOF p53 mutants perturb cellular programs relevant to oncogenesis are only partially known. We have previously demonstrated that SLC25A1 (CIC) promotes tumorigenesis, while its inhibition blunts tumor growth. We now report that CIC is a direct transcriptional target of several p53 mutants. We identify a novel interaction between mutant p53 (mutp53) and the transcription factor FOXO-1 which is responsible for regulation of CIC expression levels. Tumor cells harboring mutp53 display higher CIC levels relative to p53 null or wild-type tumors, and inhibition of CIC activity blunts mutp53-driven tumor growth, partially overcoming GOF activity. CIC inhibition also enhances the chemotherapeutic potential of platinum-based agents. Finally, we found that elevated CIC levels predict poor survival outcome in tumors hallmarked by high frequency of p53 mutations. Our results identify CIC as a novel target of mutp53 and imply that the employment of CIC inhibitors may improve survival rates and reduce chemo-resistance in tumors harboring these types of mutations, which are among the most intractable forms of cancers.

A novel differential diagnostic model for multiple primary lung cancer: Differentially-expressed gene analysis of multiple primary lung cancer and intrapulmonary metastasis

The incidence of synchronous multiple primary lung cancer (MPLC) is increasing. However, present diagnostic methods are unable to satisfy the individualized treatment requirements of patients with MPLC. The present study aimed to establish a quantitative mathematical model and analyze its diagnostic value for distinguishing between MPLC and cases of the histologically similar disease, intrapulmonary metastasis (IPM). The sum value of the differential expression ratios of four proteins, namely p53, p16, p27 and c-erbB2, was evaluated by immunohistochemically-staining specimens of primary cancers, second separate cancers, metastatic lymph nodes and metastatic cancers. The sum value of the differential expression ratio of the four proteins from the primary tumor and the lymph-node metastasis or metastatic cancer was <90 in the 11 patients with a single metastatic cancer and in the 30 patients with lymph-node metastasis, but was >90 in the 14 patients with different histological types of MPLC. Therefore, a quantitative differentially-expressed gene mathematical model was established as follows: Sum of the differential expression ratios = p16T1 - T + p27T1 - T2 + C-erbB2T1 - T2 + p53T1 - T2, where T1 is the primary cancer and T2 is the lymph node metastasis, metastatic cancer or the second separate cancer. The quantitative differentially-expressed gene mathematical model is considered to be a useful tool for distinguishing between MPLC and IPM.

The Tumor Cytosol miRNAs, Fluid miRNAs, and Exosome miRNAs in Lung Cancer

The focus of this review is to provide an update on the progress of microRNAs (miRNAs) as potential biomarkers for lung cancer. miRNAs are single-stranded, small non-coding RNAs that regulate gene expression and show tissue-specific signatures. Accumulating evidence indicates that miRNA expression patterns represent the in vivo status in physiology and disease. Moreover, miRNAs are stable in serum and other clinically convenient and available tissue sources, so they are being developed as biomarkers for cancer and other diseases. Cancer is currently the primary driver of the field, but miRNA biomarkers are being developed for many other diseases such as cardiovascular and central nervous system diseases. Here, we examine the framework and scope of the miRNA landscape as it specifically relates to the translation of miRNA expression patterns/signatures into biomarkers for developing diagnostics for lung cancer. We focus on examining tumor cytosol miRNAs, fluid miRNAs, and exosome miRNAs in lung cancer, the connections among these miRNAs, and the potential of miRNA biomarkers for the development of diagnostics. In lung cancer, miRNAs have been studied in both cell populations and in the circulation. However, a major challenge is to develop biomarkers to monitor cancer development and to identify circulating miRNAs that are linked to cancer stage. Importantly, the fact that miRNAs can be successfully harvested from biological fluids allows for the development of biofluid biopsies, in which miRNAs as circulating biomarkers can be captured and analyzed ex vivo. Our hope is that these minimally invasive entities provide a window to the in vivo milieu of the patients without the need for costly, complex invasive procedures, rapidly moving miRNAs from research to the clinic.

Mutations of epigenetic regulatory genes are common in thymic carcinomas

Genetic alterations and etiology of thymic epithelial tumors (TETs) are largely unknown, hampering the development of effective targeted therapies for patients with TETs. Here TETs of advanced-stage patients enrolled in a clinical trial of molecularly-guided targeted therapies were employed for targeted sequencing of 197 cancer-associated genes. Comparative sequence analysis of 78 TET/blood paired samples obtained from 47 thymic carcinoma (TC) and 31 thymoma patients revealed a total of 86 somatic non-synonymous sequence variations across 39 different genes in 33 (42%) TETs. TCs (62%; 29/47) showed higher incidence of somatic non-synonymous mutations than thymomas (13%; 4/31; p < 0.0001). TP53 was the most frequently mutated gene in TETs (n = 13; 17%), especially in TCs (26%), and was associated with a poorer overall survival (p < 0.0001). Genes in histone modification [BAP1 (n = 6; 13%), SETD2 (n = 5; 11%), ASXL1 (n = 2; 4%)], chromatin remodeling [SMARCA4 (n = 2; 4%)], and DNA methylation [DNMT3A (n = 3; 7%), TET2 (n = 2; 4%), WT1 (n = 2; 4%)] pathways were recurrently mutated in TCs, but not in thymomas. Our results suggest a potential disruption of epigenetic homeostasis in TCs, and a substantial difference in genetic makeup between TCs and thymomas. Further investigation is warranted into the roles of epigenetic dysregulation in TC development and its potential for targeted therapy.

Tumor heterogeneity and resistance to EGFR-targeted therapy in advanced nonsmall cell lung cancer: challenges and perspectives

Lung cancer, mostly nonsmall cell lung cancer, continues to be the leading cause of cancer-related death worldwide. With the development of tyrosine kinase inhibitors that selectively target lung cancer-related epidermal growth factor receptor mutations, management of advanced nonsmall cell lung cancer has been greatly transformed. Improvements in progression-free survival and life quality of the patients were observed in numerous clinical studies. However, overall survival is not prolonged because of later-acquired drug resistance. Recent studies reveal a heterogeneous subclonal architecture of lung cancer, so it is speculated that the tumor may rapidly adapt to environmental changes via a Darwinian selection mechanism. In this review, we aim to provide an overview of both spatial and temporal tumor heterogeneity as potential mechanisms underlying epidermal growth factor receptor tyrosine kinase inhibitor resistance in nonsmall cell lung cancer and summarize the possible origins of tumor heterogeneity covering theories of cancer stem cells and clonal evolution, as well as genomic instability and epigenetic aberrations in lung cancer. Moreover, investigational measures that overcome heterogeneity-associated drug resistance and new assays to improve tumor assessment are also discussed.

Involvement of p53 mutation and mismatch repair proteins dysregulation in NNK-induced malignant transformation of human bronchial epithelial cells

Genome integrity is essential for normal cellular functions and cell survival. Its instability can cause genetic aberrations and is considered as a hallmark of most cancers. To investigate the carcinogenesis process induced by tobacco-specific carcinogen NNK, we studied the dynamic changes of two important protectors of genome integrity, p53 and MMR system, in malignant transformation of human bronchial epithelial cells after NNK exposure. Our results showed that the expression of MLH1, one of the important MMR proteins, was decreased early and maintained the downregulation during the transformation in a histone modification involved and DNA methylation-independent manner. Another MMR protein PMS2 also displayed a declined expression while being in a later stage of transformation. Moreover, we conducted p53 mutation analysis and revealed a mutation at codon 273 which led to the replacement of arginine by histidine. With the mutation, DNA damage-induced activation of p53 was significantly impaired. We further reintroduced the wild-type p53 into the transformed cells, and the malignant proliferation can be abrogated by inducing cell cycle arrest and apoptosis. These findings indicate that p53 and MMR system play an important role in the initiation and progression of NNK-induced transformation, and p53 could be a potential therapeutic target for tobacco-related cancers.

Molecular biology of lung cancer

Lung cancers are characterised by abundant genetic diversity with relatively few recurrent mutations occurring at high frequency. However, the genetic alterations often affect a common group of oncogenic signalling pathways. There have been vast improvements in our understanding of the molecular biology that underpins lung cancer in recent years and this has led to a revolution in the diagnosis and treatment of lung adenocarcinomas (ADC) based on the genotype of an individual's tumour. New technologies are identifying key and potentially targetable genetic aberrations not only in adenocarcinoma but also in squamous cell carcinoma (SCC) of the lung. Lung cancer mutations have been identified in v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS), epidermal growth factor receptor (EGFR), BRAF and the parallel phosphatidylinositol 3-kinase (PI3K) pathway oncogenes and more recently in MEK and HER2 while structural rearrangements in ALK, ROS1 and possibly rearranged during transfection (RET) provide new therapeutic targets. Amplification is another mechanism of activation of oncogenes such as MET in adenocarcinoma, fibroblastgrowth factor receptor 1 (FGFR1) and discoidin domain receptor 2 (DDR2) in SCC. Intriguingly, many of these genetic alternations are associated with smoking status and with particular racial and gender differences, which may provide insight into the mechanisms of carcinogenesis and role of host factors in lung cancer development and progression. The role of tumour suppressor genes is increasingly recognised with aberrations reported in TP53, PTEN, RB1, LKB11 and p16/CDKN2A. Identification of biologically significant genetic alterations in lung cancer that lead to activation of oncogenes and inactivation of tumour suppressor genes has the potential to provide further therapeutic opportunities. It is hoped that these discoveries may make a major contribution to improving outcome for patients with this poor prognosis disease.

PICT1 expression is a poor prognostic factor in non-small cell lung cancer

PICT1 is a key regulator of the MDM2–TP53 pathway. High mRNA expression levels of PICT1 are associated with poor prognosis in several cancers with wild-type TP53. In this study, we identified the PICT1 protein expression profile in non-small cell lung cancer (NSCLC) with wild-type TP53 in the nucleolus and cytoplasm, and revealed the relationship between PICT1 expression and patient clinicopathological factors. PICT1 expression in the tumor cells of 96 NSCLC patients with wild-type TP53 was evaluated by immunohistochemistry. Forty-three of 96 (44.8%) NSCLC samples were positive for nucleolar PICT1, while 40/96 (41.7%) NSCLC samples were positive for cytoplasmic PICT1. There was no correlation between nucleolar PICT1 expression and clinicopathological factors. However, cytoplasmic PICT1 expression was significantly correlated with sex, smoking history, differentiation, lymphatic invasion and pathological stage. In multivariate analysis, lymphatic invasion was significantly associated with cytoplasmic PICT1 expression (hazard ratio: 5.02, P = 0.026). We scrutinized PICT1 expression in samples of NSCLC with wild-type TP53, and showed a correlation between cytoplasmic PICT1 expression and several clinicopathological factors in these patients. Our results indicate that cytoplasmic PICT1 expression is a poor prognostic factor and is associated with tumor progression via lymphatic invasion in these patients.