MicroRNAs and lung cancer: Biology and applications in diagnosis and prognosis

MicroRNA-143 act as a tumor suppressor microRNA in human lung cancer cells by inhibiting cell proliferation, invasion, and migration

BACKGROUND/AIM

MicroRNAs play crucial roles in controlling cellular biological processes. miR-143 expression is usually downregulated in different cancers. In this study, we focused on exploring the role of miR143 in NSCLC development.

METHODS

Bioinformatics analyses were used to detect the expression level of miR-143 in lung tumors. The cells were transfected by pCMV-miR-143 vectors. The efficacy of transfection was verified by Flow cytometry. The influence of miR-143 replacement on NSCLC cells migration, proliferation, and apoptosis was detected using wound-healing assay, MTT assay, and DAPI staining, respectively.

RESULTS

MTT assay revealed that overexpression of miR143 inhibited cell growth and proliferation. Scratch assay results demonstrated that restoration of miR143 suppressed cell migration. The qRT-PCR assay was further used to detect the assumed relationship between miR143 and apoptotic and metastatic-related genes.

CONCLUSION

The findings showed that miR-143 could reduce cell proliferation, invasion, and migration by reducing CXCR4, Vimentin, MMP-1, Snail-1, C-myc expression level, and increasing E-cadherin expression levels in lung cancer cells and might be a potential target in NSCLC's targeted therapy.

Smartphone-Based Platforms for Clinical Detections in Lung-Cancer-Related Exhaled Breath Biomarkers: A Review

Lung cancer has been studied for decades because of its high morbidity and high mortality. Traditional methods involving bronchoscopy and needle biopsy are invasive and expensive, which makes patients suffer more risks and costs. Various noninvasive lung cancer markers, such as medical imaging indices, volatile organic compounds (VOCs), and exhaled breath condensates (EBCs), have been discovered for application in screening, diagnosis, and prognosis. However, the detection of markers still relies on bulky and professional instruments, which are limited to training personnel or laboratories. This seriously hinders population screening for early diagnosis of lung cancer. Advanced smartphones integrated with powerful applications can provide easy operation and real-time monitoring for healthcare, which demonstrates tremendous application scenarios in the biomedical analysis region from medical institutions or laboratories to personalized medicine. In this review, we propose an overview of lung-cancer-related noninvasive markers from exhaled breath, focusing on the novel development of smartphone-based platforms for the detection of these biomarkers. Lastly, we discuss the current limitations and potential solutions.

Alkylating Agents, the Road Less Traversed, Changing Anticancer Therapy

Cancer is considered one of the gruelling challenges and poses a grave health hazard across the globe. According to the International Agency for Research on Cancer (IARC), new cancer diagnoses increased to 18.1 million in 2018, with 9.6 million deaths, bringing the global cancer rate to 23.6 million by 2030. In 1942, the discovery of nitrogen mustard as an alkylating agent was a tremendous breakthrough in cancer chemotherapy. It acts by binding to the DNA, and creating cross linkages between the two strands, leading to arrest of DNA replication and eventual cell death. Nitrogen lone pairs of 'nitrogen mustard' produce an intermediate 'aziridinium ion' at molecular level, which is very reactive towards DNA of tumour cells, resulting in multiple side effects with therapeutic consequences. Owing to its high reactivity and peripheral cytotoxicity, several improvements have been made with structural modifications for the past 75 years to enhance its efficacy and improve the direct transport of drugs to the tumour cells. Alkylating agents were among the first non-hormonal substances proven to be active against malignant cells and also, the most valuable cytotoxic therapies available for the treatment of leukaemia and lymphoma patients. This review focus on the versatile use of alkylating agents and the structure activity relationship (SAR) of each class of these compounds. This could provide an understanding for design and synthesis of new alkylating agents having enhanced target specificity and adequate bioavailability.

Inhibition Sequence of miR-205 Hinders the Cell Proliferation and Migration of Lung Cancer Cells by Regulating PETN-Mediated PI3K/AKT Signal Pathway

The aim of this study was to identify the pro-tumor role of miR-205 in patients with lung cancer (LC) on the cell proliferation and migration through regulating PTEN-mediated PI3K/AKT signal pathway. Paired cancer tissues and adjacent tissues were collected from 107 LC patients who received treatment in Jinan Central hospital. In addition, the purchased LC cell lines were transfected into HCC827 cell line to observe and compare the biological behaviors. Compared with adjacent tissues, miR-205 was statistically higher in LC tissues, while PTEN was notably lower (P < 0.05). Inhibition of miR-205 not only suppressed cell proliferation, migration and invasion, increased apoptosis rate, but regulated epithelial mesenchymal transformation (EMT)-related proteins. Likewise, overexpression of PETN played the same role as that of miR-205 inhibition sequence. Inhibited miR-205 or PTEN overexpression brought dramatically decreased PI3K and p-Akt. The relationship between miR-205 and PTEN was verified through the biological prediction website and luciferase reporter. Co-transfection experiments revealed that after cotransfection of miR-205 inhibitor and si-PETN, the cell proliferation and invasion showed no marked difference between cotransfection group and NC group. MiR-205 is involved in LC cell proliferation and migration by regulating PETN-mediated PI3K/AKT signal pathway, which may be a feasible treatment target for LC in clinical practice.

miR375-3p Distinguishes Low-Grade Neuroendocrine From Non-neuroendocrine Lung Tumors in FFPE Samples

Lung cancer is still one of the leading cause of death worldwide. The clinical variability of lung cancer is high and drives treatment decision. In this context, correct discrimination of pulmonary neuroendocrine tumors is still of critical relevance. The spectrum of neuroendocrine tumors is various, and each type has molecular and phenotypical differences. In order to advance in the discrimination of neuroendocrine from non-neuroendocrine lung tumors, we tested a series of 95 surgically resected and formalin-fixed paraffin embedded lung cancer tissues, and we analyzed the expression of miR205-5p and miR375-3p via TaqMan RT-qPCR. Via a robust mathematical approach, we excluded technical outliers increasing the data reproducibility. We found that miR375-3p levels are higher in low-grade neuroendocrine lung tumor samples compared to non-neuroendocrine lung tumors. However, miR375-3p is not able to distinguish among different types of neuroendocrine lung tumors. In this work, we provide a new molecular marker for distinguishing non-neuroendocrine from low-grade neuroendocrine lung tumors samples establishing an easy miRNA score to be used in clinical settings, enabling the pathologist to classify more accurately lung tumors biopsies, which may be ambiguously cataloged in routine examination.

Alkylating anticancer agents and their relations to microRNAs

Alkylating agents represent an important class of anticancer drugs. The occurrence and emergence of tumor resistance to the treatment with alkylating agents denotes a severe problem in the clinics. A detailed understanding of the mechanisms of activity of alkylating drugs is essential in order to overcome drug resistance. In particular, the role of non-coding microRNAs concerning alkylating drug activity and resistance in various cancers is highlighted in this review. Both synthetic and natural alkylating agents, which are approved for cancer therapy, are discussed concerning their interplay with microRNAs.

microRNA-149 targets caspase-2 in glioma progression

Malignant gliomas are the most common form of intrinsic primary brain tumors worldwide. Alterations in microRNAs play a role in highly invasive malignant glioma, but detail mechanism still unknown. In this study, the role and mechanism of microRNA-149 (miR-149) in glioma are investigated. We show that miR-149 is expressed at substantially higher levels in glioma than in normal tissues. Stable overexpression of miR-149 augments potent prosurvival activity, as evidenced by promotion of cell viability, inhibition of apoptosis, and induced xenografted tumor growth in vivo. We further show that Caspase-2 is identified as a functional target of miR-149 and expression of caspase-2 is inversely associated with miR-149 in vitro. In addition, miR-149 promotes tumor survival in the U87-MG and A172 cell lines and it targets caspase-2 via inactivation of the p53 and p21 pathways. There results support a special role for miR-149 by targeting Caspase-2 to impact on p53 signaling pathway. We speculate that miR-149 has distinct biological functions in p53 wild type cells and p53 mutation cells, and the mechanisms involved remain to be explored in future. Our study suggests that targeting miR-149 may be a novel therapy strategy for treating p53 wild type glioma tumors in humans.

Using Dual Fluorescence Reporting Genes to Establish an In Vivo Imaging Model of Orthotopic Lung Adenocarcinoma in Mice

PURPOSE

Lung adenocarcinoma is characterized by a poor prognosis and high mortality worldwide. In this study, we purposed to use the live imaging techniques and a reporter gene that generates highly penetrative near-infrared (NIR) fluorescence to establish a preclinical animal model that allows in vivo monitoring of lung cancer development and provides a non-invasive tool for the research on lung cancer pathogenesis and therapeutic efficacy.

PROCEDURES

A human lung adenocarcinoma cell line (A549), which stably expressed the dual fluorescence reporting gene (pCAG-iRFP-2A-Venus), was used to generate subcutaneous or orthotopic lung cancer in nude mice. Cancer development was evaluated by live imaging via the NIR fluorescent signals from iRFP, and the signals were verified ex vivo by the green fluorescence of Venus from the gross lung. The tumor-bearing mice received miR-16 nucleic acid therapy by intranasal administration to demonstrate therapeutic efficacy in this live imaging system.

RESULTS

For the subcutaneous xenografts, the detection of iRFP fluorescent signals revealed delicate changes occurring during tumor growth that are not distinguishable by conventional methods of tumor measurement. For the orthotopic xenografts, the positive correlation between the in vivo iRFP signal from mice chests and the ex vivo green fluorescent signal from gross lung tumors and the results of the suppressed tumorigenesis by miR-16 treatment indicated that lung tumor size can be accurately quantified by the emission of NIR fluorescence. In addition, orthotopic lung tumor localization can be accurately visualized using iRFP fluorescence tomography in vivo, thus revealing the trafficking of lung tumor cells.

CONCLUSIONS

We introduced a novel dual fluorescence lung cancer model that provides a non-invasive option for preclinical research via the use of NIR fluorescence in live imaging of lung.

MiR-205 as a promising biomarker in the diagnosis and prognosis of lung cancer

MicroRNA-205 (miR-205) was revealed as a novel diagnostic and prognostic biomarker for lung cancer, but the results in the published papers were inconsistent. This meta-analysis aimed to investigate the diagnostic and prognostic roles of miR-205 in patients with lung cancer. Totally, 16 eligible articles were included, among which 10 articles investigated the diagnostic value of miR-205, 5 articles examined its prognostic values, and 1 article studied both diagnostic and prognostic values. For the diagnostic meta-analysis, the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and the overall area under the curve of miR-205 for patients with lung cancer were 0.88 (95% CI = 0.78 – 0.94), 0.78 (95% CI = 0.66 – 0.86), 4.00 (95% CI = 2.47 – 6.49), 0.16 (95% CI = 0.08 – 0.30), 25.86 (95% CI = 9.29 – 71.95), and 0.90 (95% CI = 0.87 – 0.92), respectively, indicating that miR-205 is a useful biomarker for diagnostic of lung cancer. The subgroup analysis further demonstrated that miR-205 had an excellent overall accuracy for detection with tissue samples compare with blood samples. For the prognostic meta-analysis, the pooled outcome of the disease-free survival and recurrence-free survival analyses revealed that increased miR-205 levels had a protective role in the prognosis of patients with lung cancer (pooled HR = 0.86, 95% CI: 0.78-0.96, z = 2.83, P = 0.005). In conclusion, miR-205 may be a promising biomarker for detection, predicting the recurrence of patients with lung cancer.

Interactions between anticancer active platinum complexes and non-coding RNAs/microRNAs

Platinum(II) complexes such as cisplatin, carboplatin and oxaliplatin are clinically approved for the therapy of various solid tumors. Challenging pathogenic properties of cancer cells and the response of cancers towards platinum-based drugs are strongly influenced by non-coding small RNA molecules, the microRNAs (miRNAs). Both increased platinum activity and formation of tumor resistance towards platinum drugs are controlled by miRNAs. This review gives an overview of the interactions between platinum-based drugs and miRNAs, and their influence on platinum activity in various cancer types is discussed.

Massive parallel sequencing and digital gene expression analysis reveals potential mechanisms to overcome therapy resistance in pulmonary neuroendocrine tumors

Background: Lung cancer is the leading cause of cancer-related deaths worldwide. 25% show neuroendocrine differentiation (typical/atypical carcinoids, large-/small-cell neuroendocrine carcinomas). Carcinoids present with long survival rates, but metastatic carcinoids correlate with decreased survival and are commonly insensitive to standard chemotherapy or radiation. Therefore, novel therapeutic strategies are urgently needed.

Material and methods: 70 representative tumor specimens were used for next-generation sequencing analysis of 14 genes related to therapy response. Additionally, mRNA-expression profiles of 60 matching samples were determined for 13 selected drug targets by using the NanoString nCounter technology.

Results: A number of features known to sensitize tumors for different targeted therapies could be identified, which hopefully improve the clinical management of this subgroup of lung neoplasias. In particular, EGFR expression was observed in the investigated tumors in a noteworthy manner. Additionally, MDM2 was strongly expressed in the majority of all samples whereas the expression of its physiological inhibitor, CDKN2A, was nearly absent in all low-grade tumors. TP53 showed a high frequency of variants in high-grade tumors but mutations were rare in carcinoids.

Conclusion: Based on our results, therapeutic approaches with MDM2-inhibitors and monoclonal anti-EGFR antibodies may be promising in pulmonary carcinoid tumors.

Non-coding RNA/microRNA-modulatory dietary factors and natural products for improved cancer therapy and prevention: Alkaloids, organosulfur compounds, aliphatic carboxylic acids and water-soluble vitamins

Non-coding small RNA molecules, the microRNAs (miRNAs), contribute decisively to the epigenetic regulation processes in cancer cells. Problematic pathogenic properties of cancer cells and the response of cancers towards anticancer drugs are highly influenced by miRNAs. Both increased drug activity and formation of tumor resistance are regulated by miRNAs. Further to this, the survival and proliferation of cancer cells and the formation of metastases is based on the modulated expression of certain miRNAs. In particular, drug-resistant cancer stem-like cells (CSCs) depend on the presence and absence of specific miRNAs. Fortunately, several small molecule natural compounds were discovered that target miRNAs involved in the modulation of tumor aggressiveness and drug resistance. This review gives an overview of the effects of a selection of naturally occurring small molecules (alkaloids, organosulfur compounds, aliphatic carboxylic acids and water-soluble vitamins) on miRNAs that are closely tangled with cancer diseases.

Current state of phenolic and terpenoidal dietary factors and natural products as non-coding RNA/microRNA modulators for improved cancer therapy and prevention

The epigenetic regulation of cancer cells by small non-coding RNA molecules, the microRNAs (miRNAs), has raised particular interest in the field of oncology. These miRNAs play crucial roles concerning pathogenic properties of cancer cells and the sensitivity of cancer cells towards anticancer drugs. Certain miRNAs are responsible for an enhanced activity of drugs, while others lead to the formation of tumor resistance. In addition, miRNAs regulate survival and proliferation of cancer cells, in particular of cancer stem-like cells (CSCs), that are especially drug-resistant and, thus, cause tumor relapse in many cases. Various small molecule compounds were discovered that target miRNAs that are known to modulate tumor aggressiveness and drug resistance. This review comprises the effects of naturally occurring small molecules (phenolic compounds and terpenoids) on miRNAs involved in cancer diseases.

Low expression of miR-192 in NSCLC and its tumor suppressor functions in metastasis via targeting ZEB2

Objectives

Lung cancer is the leading cause of cancer-related death, with non-small cell lung cancer (NSCLC) accounting for more than 80% of all lung cancer cases. The aim of this study was to investigate the function and underlying mechanism of microRNA-192 (miR-192) in metastasis of NSCLC cells.

Methods

Real-time PCR was applied to quantify the expression of miR-192 in NSCLC tissues and cell lines, matched with their corresponding controls. The biological roles of miR-192 were studied in NSCLC cells using the wound healing and trans well invasion assays. Real-time PCR and western blot were used to evaluate the regulation of ZEB2 by miR- 192.

Results

MiR-192 was expressed significantly lower in NSCLC tissues/cells when compared with controls. Ectopic expression of miR-192 strongly inhibited cell migration and invasion in NSCLC A549 cells. Further investigation revealed ZEB2, an EMT regulator, was one of the downstream targets regulated by miR-192.

Conclusion

These results suggested that miR-192 inhibits the metastasis of NSCLC cells by targeting ZEB2, and thus is an important tumor suppressor.

MicroRNA 192 regulates chemo-resistance of lung adenocarcinoma for gemcitabine and cisplatin combined therapy by targeting Bcl-2

Lung cancer is the most leading cause of cancer-related death worldwide, with non-small-cell lung cancer (NSCLC) accounting for over 80% of all lung cancer cases. Patients with NSCLC are mostly treated with platinum-based chemotherapy. Chemoresistance is a leading cause of chemo-therapy failure in NSCLC treatment. Recent studies have shown that dysregulation of microRNAs might modulate the resistance of cancer cells to anti-cancer drugs, yet the modulation mechanism is not fully understood. In this paper, we try to test whether miR-192 regulates chemo-resistance in human carcinoma A549 mice model by targeting Bcl-2. Mice model of human lung adenocarcinoma was built up, and was used for gemcitabine and cisplatin combined chemotherapy. MTT assay, real-time RT-PCR, western blotting assay were used to investigate miR-192 expression levels, cell viability ratio and Bcl-2 protein expression levels. MiR-192 expression level in A549 cells is significantly higher than in normal human bronchial epithelial cells. MiR-192 inhibitor treated tumor exhibits sensitivity to cisplatin and gemcitabine therapy. Bcl-2 mRNA and protein expression levels up-regulated in miR-192 inhibitor treated tumor. Bcl-2 is a key regulator for miR-192 related chemotherapy resistance. In this study, we demonstrate that miR-192 regulates chemoresistance for gemcitabine and cisplatin combined chemotherapy in human adenocarcinoma lung cancer A549 cells, and Bcl-2 is the target of miR-192.

Quercetin Decreases Claudin-2 Expression Mediated by Up-Regulation of microRNA miR-16 in Lung Adenocarcinoma A549 Cells

Claudin-2 is highly expressed in human lung adenocarcinoma tissues and cells. Knockdown of claudin-2 decreases cell proliferation and migration. Claudin-2 may be a novel target for lung adenocarcinoma. However, there are no physiologically active substances of foods which decrease claudin-2 expression. We here found that quercetin, a flavonoid present in fruits and vegetables, time- and concentration-dependently decreases claudin-2 expression in lung adenocarcinoma A549 cells. In the present study, we examined what regulatory mechanism is involved in the decrease in claudin-2 expression by quercetin. Claudin-2 expression was decreased by LY-294002, a phosphatidylinositol 3-kinase (PI3-K) inhibitor, and U0126, a MEK inhibitor. These drugs inhibited the phosphorylation of Akt and ERK1/2, which are downstream targets of PI3-K and MEK, respectively. In contrast, quercetin did not inhibit the phosphorylation. Both LY-294002 and U0126 inhibited promoter activity of claudin-2, but quercetin did not. The stability of claudin-2 mRNA was decreased by quercetin. Quercetin increased the expression of microRNA miR-16. An inhibitor of miR-16 rescued quercetin-induced decrease in the claudin-2 expression. These results suggest that quercetin decreases claudin-2 expression mediated by up-regulation of miR-16 expression and instability of claudin-2 mRNA in lung adenocarcinoma cells.

Prognostic and predictive biomarkers in early stage NSCLC: CTCs and serum/plasma markers

Resection of early stage non-small cell lung cancer (NSCLC) offers patients the best hope of cure, however recurrence rates post-resection remain high suggesting the presence of micro-metastatic disease at the time of surgery undetected by standard staging methods. A critical step in the metastatic cascade is the entry of tumor cells into the circulation enabling their distribution to and seeding of distant organs. This review explores the evidence for predictive and prognostic circulating biomarkers in the early stage NSCLC population. We summarize studies that have explored a variety of targets including circulating proteins, nucleic acids and more recently circulating tumor cells (CTCs) as potentially clinically relevant biomarkers in the early stage setting. Circulating biomarkers may add clinically relevant information about the biological behavior of tumors over and above that provided by pathological staging. Improvement in the stratification of patients according to the likelihood of metastatic relapse after radical treatments such as surgical resection could allow more effective targeting of systemic therapies such as adjuvant chemotherapy.

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.

Selective TRAIL-induced cytotoxicity to lung cancer cells mediated by miRNA response elements

Lung cancer is among the most common cancers, and the current therapeutic strategies are still inefficient in most cases. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising biological agent for cancer treatment because of its potent pro-apoptotic effect on cancer cells. However, TRAIL also induces apoptosis in normal cells and therefore may cause toxicity to normal tissues if clinically applied. To address this issue, we inserted microRNA response elements (MREs) of miR-133a, miR-137 and miR-449a, which are all underexpressed in lung cancer cells, into an adenoviral vector to regulate TRAIL expression. This MRE-regulated vector (Ad-TRAIL-MRE) was able to express TRAIL in a lung-cancer-specific fashion. No TRAIL expression was detected in normal cells. Consistently, Ad-TRAIL-MRE exerted cytotoxicity to lung cancer cells, rather than normal cells, perhaps via inducing selective apoptosis. The selective TRAIL-mediated growth-inhibiting effect was further confirmed in a tumour xenograft model. Also, Ad-TRAIL-MRE only resulted in very low hepatotoxicity when applied. Collectively, we generated a novel TRAIL-expressing adenoviral vector that was regulated by MREs. This strategy permits TRAIL expression in a lung-cancer-specific manner and is worth further studying for clinical trials.

miR-143 inhibits NSCLC cell growth and metastasis by targeting Limk1

MicroRNAs (miRNAs) have essential roles in carcinogenesis and tumor progression. Here, we investigated the roles and mechanisms of miR-143 in non-small cell lung cancer (NSCLC). miR-143 was significantly decreased in NSCLC tissues and cell lines. Overexpression of miR-143 suppressed NSCLC cell proliferation, induced apoptosis, and inhibited migration and invasion in vitro. Integrated analysis identified LIM domain kinase 1 (Limk1) as a direct and functional target of miR-143. Overexpression of Limk1 attenuated the tumor suppressive effects of miR-143 in NSCLC cells. Moreover, miR-143 was inversely correlated with Limk1 expression in NSCLC tissues. Together, our results highlight the significance of miR-143 and Limk1 in the development and progression of NSCLC.

Activation of angiogenesis differs strongly between pulmonary carcinoids and neuroendocrine carinomas and is crucial for carcinoid tumourgenesis

BACKGROUND

Lung cancer still remains the leading cause of cancer for men after prostate cancer and breast cancer for women. Angiogenesis is considered a major microenvironment modifier.

MATERIAL AND METHODS

Demographic data and study design; The study is based on a collective of twenty representative specimens of each tumour entity (Typical Carcinoid, Atypical Carcinoid, Large-Cell Neuroendocrine Carcinoma , Small Cell Lung Cancer) for mRNA expression analysis. The following methods were performed: RNA Extraction and RNA Integrity Assessment, NanoString CodeSet Design and Expression Quantification, NanoString Data Processing and Statistical Analysis.

RESULTS

KDR rendered significant association to aggressiveness of the tumour and decreases with increasing malignancy (p=0.049). A decreased expression of HIF1A and KDR mRNA as associated with a higher risk of tumour invasion in vessels (HIF1A: p=0.034; KDR: p=0.029). FIGF and HIF1A expression levels are significantly associated with progression-free survival (FIGF: p= 0.021; HIF1A: p= 0.049). CRHR2 and FLT4 are stronger expressed in female than in male patients (CRHR2: p=0.024, FLT4: p=0.004). FIGF expression is still significant between LCNEC and SCLC (p=0.023). FLT4 and KDR show highly significant association to one of the analysed groups (FLT4: p=0.001; KDR: p=0.006). Additionally, HIF1A expression differs significantly between these focus cohorts (p=0.018).

CONCLUSION

We should consider for clinical practice application which factors affect most the tumour growth and distal metastasis, thereafter investigate easy to administer drugs with low side effects. Probably a cluster system of therapy should be established where a drug targets simultaneously different pathways of the same origin.

Therapeutic evaluation of microRNAs by molecular imaging

MicroRNAs (miRNAs) function as regulatory molecules of gene expression with multifaceted activities that exhibit direct or indirect oncogenic properties, which promote cell proliferation, differentiation, and the development of different types of cancers. Because of their extensive functional involvement in many cellular processes, under both normal and pathological conditions such as various cancers, this class of molecules holds particular interest for cancer research. MiRNAs possess the ability to act as tumor suppressors or oncogenes by regulating the expression of different apoptotic proteins, kinases, oncogenes, and other molecular mechanisms that can cause the onset of tumor development. In contrast to current cancer medicines, miRNA-based therapies function by subtle repression of gene expression on a large number of oncogenic factors, and therefore are anticipated to be highly efficacious. Given their unique mechanism of action, miRNAs are likely to yield a new class of targeted therapeutics for a variety of cancers. More than thousand miRNAs have been identified to date, and their molecular mechanisms and functions are well studied. Furthermore, they are established as compelling therapeutic targets in a variety of cellular complications. However, the notion of using them as therapeutic tool was proposed only recently, given that modern imaging methods are just beginning to be deployed for miRNA research. In this review, we present a summary of various molecular imaging methods, which are instrumental in revealing the therapeutic potential of miRNAs, especially in various cancers. Imaging methods have recently been developed for monitoring the expression levels of miRNAs and their target genes by fluorescence-, bioluminescence- and chemiluminescence-based imaging techniques. Mature miRNAs bind to the untranslated regions (UTRs) of the target mRNAs and regulate target genes expressions. This concept has been used for the development of fluorescent reporter-based imaging strategies to monitor the functional status of endogenous miRNAs, or the respective miRNAs transiently co-expressed in cells. Bioluminescence-based imaging strategies have been used to investigate various stages of miRNA processing and its involvement in different cellular processes. Similarly, chemiluminsecence methods were developed for in vitro miRNA imaging such as monitoring their therapeutic roles in various cancer cell lines.

Post-transcriptional processing of genetic information and its relation to cancer

During the development, progression and dissemination of neoplastic lesions, cancer cells hijack normal pathways and mechanisms, especially those involved in repair and embryologic development. These pathways include those involved in intercellular communication, control of transcription, post-transcriptional regulation of protein production including translation of mRNAs, post-translational protein modifications, e.g., acetylation of proteins, and protein degradation. Small, non-translatable RNAs, especially microRNAs (miRs), are Important components of post-transcriptional control. MiRs are produced from areas of the genome that are not translated into proteins, but may be co-regulated with their associated genes. MiRs bind to the 3' untranslated regions of mRNAs and regulate the expression of genes in most cases by either promoting the degradation of mRNA and/or inhibiting the translation of mRNAs into proteins; thus, miRs usually cause a decrease in protein levels that would be expected if the mRNAs were translated normally. It is early in our understanding of how miRs affect neoplastic processes, but miRs are expressed differentially in most cancers and have been associated with tumor progression, chemoresistance and metastasis. MiRs are present in nanovesicles, such as exosomes, and thus are likely involved in intercellular communication, especially in neoplasia. MiRs are attractive targets for novel therapies of cancer as well as potential biomarkers that might be useful for early detection and diagnosis, and for prediction of therapeutic efficacy. MiRs also could aid and in determining prognosis, evaluating novel therapies, and developing preventive strategies by their use as surrogate end points.

miR-149 Inhibits Non-Small-Cell Lung Cancer Cells EMT by Targeting FOXM1

MicroRNAs (miRNAs) have been implied to play crucial roles for epithelial-to-mesenchymal transition (EMT) of non-small-cell lung cancer cells (NSCLC cells). Here we found that the expression of miR-149, downregulated in lung cancer, was inversely correlated with invasive capability and the EMT phenotype of NSCLC cells. miR-149 inhibited EMT in NSCLC cells. Furthermore, we demonstrated that miR-149 directly targeted Forkhead box M1 (FOXM1), and FOXM1 was involved in the EMT induced by TGF-β1 in A549 cells. Overexpression of FOXM1 restored EMT process inhibited by miR-149. Our work suggested that miR-149 might be an EMT suppressor in NSCLC cells.

Lung cancer biomarkers: State of the art

Lung cancer is one of the deadliest cancers worldwide, with the highest incidence and mortality amongst all cancers. While the prognosis of lung cancer is generally grim, with 5-year survival rates of only 15%, there is hope, and evidence, that early detection of lung cancer can reduce mortality. Today, only computed tomography screening has shown to lead to early detection and reduction in mortality, but is limited by being anatomic in nature, unable to differentiate between inflammatory and neoplastic pathways, and therefore, susceptible to false positives. There is increasing interest in biomarkers for lung cancer, especially those that predict metastatic risk. Some biomarkers like DNA mutations and epigenetic changes potentially require tissue from the at-risk site; some like serum proteins and miRNAs are minimally invasive, but may not be specific to the lung. In comparison, emerging biomarkers from exhaled breath, like volatile organic compounds (VOC), and exhaled breath condensate, e.g., small molecules and nucleic acids, have the potential to combine the best of both. This mini review is intended to provide an overview of the field, briefly discussing the potential of what is known and highlighting the exciting recent developments, particularly with miRNAs and VOCs.

Subcellular fate and off-target effects of siRNA, shRNA, and miRNA

RNA interference (RNAi) strategies include double-stranded RNA (dsRNA), small interfering RNA (siRNA), short hairpin RNA (shRNA), and microRNA (miRNA). As this is a highly specific technique, efforts have been made to utilize RNAi towards potential knock down of disease-causing genes in a targeted fashion. RNAi has the potential to selectively inhibit gene expression by degrading or blocking the translation of the target mRNA. However, delivering these RNAs to specific cells presents a significant challenge. Some of these challenges result from the necessity of traversing the circulatory system while avoiding kidney filtration, degradation by endonucleases, aggregation with serum proteins, and uptake by phagocytes. Further, non-specific delivery may result in side-effects, including the activation of immune response. We discuss the challenges in the systemic delivery to target cells, cellular uptake, endosomal release and intracellular transport of RNAi drugs and recent progress in overcoming these barriers. We also discuss approaches that increase the specificity and metabolic stability and reduce the off-target effects of RNAi strategy.

Fifth Educational Symposium of the Spanish Lung Cancer Group: report on the Molecular Biology Workshop

The majority of non-small-cell lung cancer (NSCLC) patients present with locally advanced (35%) or metastatic disease (40%); in this setting, it is of the utmost importance to balance efficacy with toxicity. However, with platinum combinations, survival has reached a "plateau", with median overall survival times of a mere 10-12 months, making it mandatory to search for new strategies and to identify more effective treatment. Molecular characteristics can be more informative than clinical features in predicting clinical benefit, and the identification of molecular markers can help define subgroups of patients who are likely to respond to different treatments, thus avoiding unnecessary toxicities and costs and providing the maximum benefit to each patient. Here we review research on biomarker assessment that was presented during the Molecular Biology Workshop held in Palma de Mallorca on 25 November 2010, during the Fifth Educational Symposium of the Spanish Lung Cancer Group.

MicroRNA gene dosage alterations and drug response in lung cancer

Chemotherapy resistance is a key contributor to the dismal prognoses for lung cancer patients. While the majority of studies have focused on sequence mutations and expression changes in protein-coding genes, recent reports have suggested that microRNA (miRNA) expression changes also play an influential role in chemotherapy response. However, the role of genetic alterations at miRNA loci in the context of chemotherapy response has yet to be investigated. In this study, we demonstrate the application of an integrative, multidimensional approach in order to identify miRNAs that are associated with chemotherapeutic resistance and sensitivity utilizing publicly available drug response, miRNA loci copy number, miRNA expression, and mRNA expression data from independent resources. By instigating a logical stepwise strategy, we have identified specific miRNAs that are associated with resistance to several chemotherapeutic agents and provide a proof of principle demonstration of how these various databases may be exploited to derive relevant pharmacogenomic results.