Combinatorial Action of MicroRNAs let-7 and miR-34 Effectively Synergizes with Erlotinib to Suppress Non-small Cell Lung Cancer Cell Proliferation

miR-203 enhances let-7 biogenesis by targeting LIN28B to suppress tumor growth in lung cancer

Human cancers often exhibit increased microRNA (miRNA) biogenesis and global aberrant expression of miRNAs; thus, targeting the miRNA biogenesis pathway represents a novel strategy for cancer therapy. Here, we report that miR-203 enhances the biogenesis of tumor suppressor let-7 in lung cancer by directly targeting LIN28B. Specially, we found that the LIN28B protein levels were dramatically increased in lung cancer tissues, but its mRNA levels did not differ significantly, suggesting that a post-transcriptional mechanism is involved in LIN28B regulation. Interestingly, miR-203 overexpression was accompanied by massive upregulation of a group of miRNAs, especially let-7, and the let-7 expression level was concordant with the miR-203 expression in lung cancer tissues, implying its biological relevance. Furthermore, we showed that miR-203 played a critical role in inhibiting the proliferation and promoting the apoptosis of lung cancer cells by suppressing LIN28B and enhancing let-7 biogenesis. In summary, our results establish a novel mechanism by which miR-203, LIN28B and let-7 are tightly linked to form a regulatory network in lung cancer cells. The findings shed light on the role of a specific miRNA as a modulator of miRNA biogenesis and provide basis for developing new strategies for lung cancer therapy.

MicroRNA therapeutics: towards a new era for the management of cancer and other diseases

In just over two decades since the discovery of the first microRNA (miRNA), the field of miRNA biology has expanded considerably. Insights into the roles of miRNAs in development and disease, particularly in cancer, have made miRNAs attractive tools and targets for novel therapeutic approaches. Functional studies have confirmed that miRNA dysregulation is causal in many cases of cancer, with miRNAs acting as tumour suppressors or oncogenes (oncomiRs), and miRNA mimics and molecules targeted at miRNAs (antimiRs) have shown promise in preclinical development. Several miRNA-targeted therapeutics have reached clinical development, including a mimic of the tumour suppressor miRNA miR-34, which reached phase I clinical trials for treating cancer, and antimiRs targeted at miR-122, which reached phase II trials for treating hepatitis. In this article, we describe recent advances in our understanding of miRNAs in cancer and in other diseases and provide an overview of current miRNA therapeutics in the clinic. We also discuss the challenge of identifying the most efficacious therapeutic candidates and provide a perspective on achieving safe and targeted delivery of miRNA therapeutics.

Integrative microRNA and gene profiling data analysis reveals novel biomarkers and mechanisms for lung cancer

BACKGROUND

Studies on the accuracy of microRNAs (miRNAs) in diagnosing non-small cell lung cancer (NSCLC) have still controversial. Therefore, we conduct to systematically identify miRNAs related to NSCLC, and their target genes expression changes using microarray data sets.

METHODS

We screened out five miRNAs and six genes microarray data sets that contained miRNAs and genes expression in NSCLC from Gene Expression Omnibus.

RESULTS

Our analysis results indicated that fourteen miRNAs were significantly dysregulated in NSCLC. Five of them were up-regulated (miR-9, miR-708, miR-296-3p, miR-892b, miR-140-5P) while nine were down-regulated (miR-584, miR-218, miR-30b, miR-522, miR486-5P, miR-34c-3p, miR-34b, miR-516b, miR-592). The integrating diagnosis sensitivity (SE) and specificity (SP) were 82.6% and 89.9%, respectively. We also found that 4 target genes (p < 0.05, fold change > 2.0) were significant correlation with the 14 discovered miRNAs, and the classifiers we built from one training set predicted the validation set with higher accuracy (SE = 0.987, SP = 0.824).

CONCLUSIONS

Our results demonstrate that integrating miRNAs and target genes are valuable for identifying promising biomarkers, and provided a new insight on underlying mechanism of NSCLC. Further, our well-designed validation studies surely warrant the investigation of the role of target genes related to these 14 miRNAs in the prediction and development of NSCLC.

Non-Coding RNAs in Lung Cancer: Contribution of Bioinformatics Analysis to the Development of Non-Invasive Diagnostic Tools

Lung cancer is currently the leading cause of cancer related mortality due to late diagnosis and limited treatment intervention. Non-coding RNAs are not translated into proteins and have emerged as fundamental regulators of gene expression. Recent studies reported that microRNAs and long non-coding RNAs are involved in lung cancer development and progression. Moreover, they appear as new promising non-invasive biomarkers for early lung cancer diagnosis. Here, we highlight their potential as biomarker in lung cancer and present how bioinformatics can contribute to the development of non-invasive diagnostic tools. For this, we discuss several bioinformatics algorithms and software tools for a comprehensive understanding and functional characterization of microRNAs and long non-coding RNAs.

MicroRNA-targeted therapeutics for lung cancer treatment

INTRODUCTION

Lung cancer is one of the leading causes of cancer-related mortality worldwide. MicroRNAs (miRNAs) are endogenous non-coding small RNAs that repress the expression of a broad array of target genes. Many efforts have been made to therapeutically target miRNAs in cancer treatments using miRNA mimics and miRNA antagonists. Areas covered: This article summarizes the recent findings with the role of miRNAs in lung cancer, and discusses the potential and challenges of developing miRNA-targeted therapeutics in this dreadful disease. Expert opinion: The development of miRNA-targeted therapeutics has become an important anti-cancer strategy. Results from both preclinical and clinical trials of microRNA replacement therapy have shown some promise in cancer treatment. However, some obstacles, including drug delivery, specificity, off-target effect, toxicity mediation, immunological activation and dosage determination should be addressed. Several delivery strategies have been employed, including naked oligonucleotides, liposomes, aptamer-conjugates, nanoparticles and viral vectors. However, delivery remains a main challenge in miRNA-targeting therapeutics. Furthermore, immune-related serious adverse events are also a concern, which indicates the complexity of miRNA-based therapy in clinical settings.

New strategies for targeting drug combinations to overcome mutation-driven drug resistance

Targeted therapies are suggested as an effective alternative for patients with cancer that harbor mutations, but treatment outcomes are frequently limited by primary or acquired drug resistance. The present review describes potential mechanisms of primary or acquired drug resistances to provide a resource for considering how to be overcome. We focus on strategies of targeted drug combinations to minimize the development of drug resistance within the context how resistance develops. Strategies benefit from the combined use of "omics" technologies, i.e., high-throughput functional genomics data, pharmacogenomics, or genome-wide CRISPR-Cas9 screening, to analyze and design targeted drug combinations for mutation-driven drug resistance. We also introduce new insights towards pathway-centric combined therapies as an alternative to overcome the heterogeneity and benefit patient prognoses.

[Advanced Research on MicroRNAs and EGFR-TKIs Secondary Resistance]

肺癌是癌症致死率最高的疾病，关于这个疾病的发生机制已得到部分阐明，其中表皮生长因子受体（epidermal growth factor receptor, EGFR）信号通路研究最为深入，在肺癌的发生中起着至关重要的作用。而有效地抑制EGFR信号通路的药物已用于非小细胞肺癌（non-small cell lung cancer, NSCLC）的靶向治疗中，伴有EGFR基因突变的患者使用EGFR酪氨酸激酶抑制剂（EGFR-tyrosine kinase inhibitors, EGFR-TKIs）治疗后获得不错的临床收益，但大部分患者在使用该药治疗10个月后出现耐药现象。MiRNAs（microRNAs）是一种非编码蛋白的RNA，参与转录后水平基因的表达调控。越来越多的研究发现miRNAs与EGFR-TKIs继发性耐药有关，miRNAs可作为逆转EGFR-TKIs耐药及评估EGFR-TKIs有效性的生物指标。本文就NSCLC中miRNAs与EGFR-TKIs继发性耐药机制之间的相关性研究进展做简要的综述。

Overexpression of microRNA-155 suppresses chemokine expression induced by Interleukin-13 in BEAS-2B human bronchial epithelial cells

BACKGROUND

MicroRNAs are non-coding small RNAs that regulate expression of target genes by binding to 3' untranslated regions. In this study, we used bronchial epithelial cells to investigate in vitro the role of the microRNA miR-155 in the expression of chemokines associated with airway inflammation. miR-155 has previously been reported to regulate allergic inflammation.

METHODS

BEAS-2B bronchial epithelial cells were cultured and transfected with mimic or inhibitor oligonucleotides to overexpress or downregulate miR-155, as confirmed by real-time PCR. Cells were then stimulated with tumor necrosis factor-alpha, interleukin-13 (IL-13), and a double stranded RNA that binds Toll-like receptor 3. Expression and secretion of the chemokines CCL5, CCL11, CCL26, CXCL8, and CXCL10 were then quantified by real-time PCR and ELISA, respectively. Phosphorylation of signal transducer and activator of transcription 6 (STAT6), a target of the IL-13 receptor, was analyzed by ELISA.

RESULTS

miR-155 overexpression significantly suppressed IL-13-induced secretion of CCL11 and CCL26. These effects were specific, and were not observed for other chemokines, nor in cells with downregulated miR-155. miR-155 overexpression also suppressed CCL11 and CCL26 mRNA, but did not affect expression of the IL-13 receptor or phosphorylation of STAT6.

CONCLUSIONS

miR-155 specifically inhibits IL-13-induced expression of eosinophilic chemokines CCL11 and CCL26 in bronchial epithelial cells, even though the 3'-untranslated region of these genes do not contain a consensus binding site for miR-155.

Tumour-initiating cell-specific miR-1246 and miR-1290 expression converge to promote non-small cell lung cancer progression

The tumour-initiating cell (TIC) model accounts for phenotypic and functional heterogeneity among tumour cells. MicroRNAs (miRNAs) are regulatory molecules frequently aberrantly expressed in cancers, and may contribute towards tumour heterogeneity and TIC behaviour. More recent efforts have focused on miRNAs as diagnostic or therapeutic targets. Here, we identified the TIC-specific miRNAs, miR-1246 and miR-1290, as crucial drivers for tumour initiation and cancer progression in human non-small cell lung cancer. The loss of either miRNA impacted the tumour-initiating potential of TICs and their ability to metastasize. Longitudinal analyses of serum miR-1246 and miR-1290 levels across time correlate their circulating levels to the clinical response of lung cancer patients who were receiving ongoing anti-neoplastic therapies. Functionally, direct inhibition of either miRNA with locked nucleic acid administered systemically, can arrest the growth of established patient-derived xenograft tumours, thus indicating that these miRNAs are clinically useful as biomarkers for tracking disease progression and as therapeutic targets.

miRNAs can function either as proto-oncogenes or tumour suppressors in several cancers; however their function in tumour initiating cells is unclear. Here, Zhang et al. show that tumour initiating cell-specific miR-1246 and miR-1290 promote lung cancer initiation and metastasis and could serve as prognostic markers.

An Artificially Designed Interfering lncRNA Expressed by Oncolytic Adenovirus Competitively Consumes OncomiRs to Exert Antitumor Efficacy in Hepatocellular Carcinoma

Endogenous miRNAs, especially oncogenic miRNAs (OncomiR), have been molecular targets for cancer therapy. We generated an artificially designed interfering long noncoding RNA (lncRNAi), which contains the sequences that can complementarily bind to multiple OncomiRs and is expressed by cancer-selectively replicating adenovirus. The adenovirus-expressed lncRNAi with high levels in hepatocellular carcinoma (HCC) cells competes with OncomiR target genes to bind to and consume OncomiRs, thereby achieving the targeted anti-HCC efficacy. With the targeting replication of adenovirus in HCC cells, lncRNAi was highly expressed and resulted in decreased abilities of proliferation, migration, and invasion, induced cell-cycle changes and apoptosis, and markedly changed the cellular mRNA and miRNA expression profiles in HCC cells. The optimal antitumor effect was also demonstrated on HCC cell line xenograft models and HCC patient-derived xenograft (PDX) tumor models in nude mice. This strategy has established a technology platform with a reliable therapeutic effect for HCC therapy. Mol Cancer Ther; 15(7); 1436-51. ©2016 AACR.

MicroRNA-34a inhibits cell proliferation and induces cell apoptosis of glioma cells via targeting of Bcl-2

Glioblastoma is a highly malignant brain tumor, characterized by the poor prognosis and high recurrence rates. Despite therapeutic strategies including surgery, radiotherapy and chemotherapy, the median survival of patients is only 14.6 months. MicroRNAs (miRNAs) have been considered as a novel type of gene regulator. Previous studies have demonstrated that the expression of miRNA‑34a (miR‑34a) is significantly associated with the grade and prognosis of glioma. However, the exact function of miR‑34a on glioma progression and underlying mechanisms remain to be elucidated. The present study investigated the function of miR‑34a in U87 human glioma cells by exogenously transfecting cells with an miR‑34a mimic. Overexpression of miR‑34a inhibited proliferation, and induced apoptosis of U87 cells. The current study also demonstrated that B‑cell lymphoma 2 (Bcl‑2) was the target gene of miR‑34a, as demonstrated by luciferase assays. Furthermore, restoring the expression of Bcl‑2 was indicated to partially block the miR‑34a‑induced apoptosis. Thus, data from the present study identified miR‑34a as a tumor suppressor in glioma by, at least partially, targeting Bcl‑2. This may provide future novel diagnostic and therapeutic strategies for human glioma.

Technological advances in precision medicine and drug development

New technologies are rapidly becoming available to expand the arsenal of tools accessible for precision medicine and to support the development of new therapeutics. Advances in liquid biopsies, which analyze cells, DNA, RNA, proteins, or vesicles isolated from the blood, have gained particular interest for their uses in acquiring information reflecting the biology of tumors and metastatic tissues. Through advancements in DNA sequencing that have merged unprecedented accuracy with affordable cost, personalized treatments based on genetic variations are becoming a real possibility. Extraordinary progress has been achieved in the development of biological therapies aimed to even further advance personalized treatments. We provide a summary of current and future applications of blood based liquid biopsies and how new technologies are utilized for the development of biological therapeutic treatments. We discuss current and future sequencing methods with an emphasis on how technological advances will support the progress in the field of precision medicine.

Prognostic Significance of MiR-34a Expression in Patients with Gastric Cancer after Radical Gastrectomy

BACKGROUND

MiR-34a dysregulation has been implicated in tumorigenesis and progression of gastric cancer, but its role in prognosis of patients with gastric cancer remains unknown. The aim of this study was to investigate the expression and prognostic significance of miR-34a in gastric cancer patients after radical gastrectomy.

METHODS

Quantitative real-time polymerase chain reaction was performed to detect the expression of miR-34a in human gastric cancer cell lines and tissues in 76 patients with gastric adenocarcinoma from China. Results are assessed for association with clinical features and overall survival (OS) using Kaplan-Meier analysis. Prognostic values of miR-34a expression and clinical outcomes were evaluated by Cox regression analysis. A molecular prognostic stratification scheme incorporating miR-34a expression was determined using receiver operating characteristic analysis.

RESULTS

The results show that the expression level of miR-34a was decreased in human gastric cancer cell lines and tissues, and down-regulated expression of miR-34a was associated with Lauren classification (P = 0.034). Decreased miR-34a expression in gastric cancer tissues was positively correlated with poor OS of gastric cancer patients (P = 0.013). Further multivariate Cox regression analysis suggested that miR-34a expression was an independent prognostic indicator for gastric cancer (P = 0.027). Applying the prognostic value of miR-34a expression to tumor node metastasis (TNM) stage system showed a better prognostic value in patients with gastric cancer than miR-34a expression (P = 0.0435) or TNM stage (P = 0.0249) alone.

CONCLUSION

The results reinforce the critical role for the down-regulated miR-34a expression in gastric cancer and suggest that miR-34a could be a prognostic indicator for this disease.

Implications of MicroRNAs in the Treatment of Gefitinib-Resistant Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) represents about 85% of the reported cases of lung cancer. Acquired resistance to targeted therapy with epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib, is not uncommon. It is thus vital to explore novel strategies to restore sensitivity to gefitinib. Provided that microRNAs (miRNAs) negatively regulate their gene targets at the transcriptional level, it is speculated that miRNA mimetics may reduce the expression, activity and signal transduction of EGFR so that sensitization of tumour sites to gefitinib-induced cytotoxicity can be achieved. Indeed, a growing body of evidence has shown that the manipulation of endogenous levels of miRNA not only attenuates the EGFR/PI3K/Akt phosphorylation cascade, but also restores apoptotic cell death in in vitro models of experimentally-induced gefitinib resistance and provoked tumour regression/shrinkage in xenograft models. These data are in concordant with the clinical data showing that the differential expression profiles of miRNA in tumour tissues and blood associate strongly with drug response and overall survival. Furthermore, another line of studies indicate that the chemopreventive effects of a variety of natural compounds may involve miRNAs. The present review aims to discuss the therapeutic capacity of miRNAs in relation to recent discoveries on EGFR-TKI resistance, including chronic drug exposure and mutations.

The tumor-suppressive and potential therapeutic functions of miR-34a in epithelial carcinomas

INTRODUCTION

Many RNA species have been identified as important players in the development of chronic diseases including cancer. Certain classes of regulatory RNAs such as microRNAs (miRNAs) have been investigated in such detail that bona fide tumor suppressive and oncogenic miRNAs have been identified. Because of this, there has been a major effort to therapeutically target these small RNAs. One in particular, a liposomal formulation of miR-34a (MRX34), has entered Phase I trials.

AREAS COVERED

This review aims to summarize miRNA biology, its regulation within normal versus disease states and how it can be targeted therapeutically, with a particular emphasis on miR-34a. Understanding the complexity of a single miRNA will aid in the development of future RNA-based therapeutics for a broader range of chronic diseases.

EXPERT OPINION

The potential of miRNAs to be developed into anti-cancer therapeutics has become an increasingly important area of research. miR-34a is a tumor suppressive miRNA across many tumor types through its ability to inhibit cellular proliferation, invasion and tumor sphere formation. miR-34a also shows promise within certain in vivo solid tumor models. Finally, as miR-34a moves into clinical trials it will be important to determine if it can further sensitize tumors to certain chemotherapeutic agents.

siRNA delivered by EGFR-specific scFv sensitizes EGFR-TKI-resistant human lung cancer cells

The overexpression of epidermal growth factor receptor (EGFR) is closely associated with a poor outcome in non-small cell lung cancer (NSCLC), and EGFR is an ideal biomarker for the targeted therapy of NSCLC. Although patients with EGFR-activating mutations respond to EGFR tyrosine kinase inhibitors (EGFR-TKIs), they eventually acquire resistance, which typically results from a secondary EGFR mutation or the activation of other signaling pathways. Novel approaches to overcome or prevent EGFR-TKI resistance are clinically important. In this study, we developed an EGFR-scFv-arginine nonamer peptide fusion protein, s-9R, as an siRNA carrier. Here, we show that s-9R effectively and specifically delivers EGFR-siRNAs, KRAS-siRNA and MET-siRNA into NSCLC cells and silences the expression of target genes. The sensitivity of NSCLC cells to gefitinib was restored after treatment with the s-9R/siRNA complex, and the apoptosis rates of the treated cells were significantly higher than those of the control groups. Furthermore, the co-administration of s-9R/siRNA and gefitinib successfully suppressed the progression of H1975 xenograft tumors and extended the life span of tumor-bearing nude mice. Collectively, the results of this study provide not only a new scFv derivative for delivering siRNA into EGFR-overexpressing, TKI-resistant NSCLC cells but also a novel method for overcoming TKI resistance.

MicroRNA-96 plays an oncogenic role by targeting FOXO1 and regulating AKT/FOXO1/Bim pathway in papillary thyroid carcinoma cells

MicroRNAs (miRNAs) are kind of small non-coding RNAs that negatively regulate gene expression at post-transcription level, and those non-coding RNAs appear to play a key role in tumorigenesis. The aim of this study was to investigate the biological role of miR-96 in papillary thyroid carcinoma (PTC) cell lines. We identified miR-96 to be up-regulated in PTC specimens in comparison to matched normal tissues by microRNA microarray and RT-qPCR analysis (P < 0.05). Next, to explore the potential function of miR-96, PTC cell lines K1 and TPC1 were transiently transfected with miR-96 mimics and inhibitor. Successful transfection being confirmed by RT-qPCR. Ectopic expression of miR-96 promoted proliferation and colony formation ability, and inhibited apoptosis of K1 and TPC1 cells, whereas down-regulated expression of miR-96 suppressed those functions when compared with the control cells. According to a computational prediction, FOXO1 maybe a potential target of miR-96. Luciferase assays revealed that miR-96 is directly targeted to both binding sites of FOXO1 3'-untranslated region (3'-UTR) and suppressed the FOXO1 expression, and subsequently inhibited the expression of Bim protein in PTC cells. Moreover, the expression of FOXO1 had an inverse correlation with expression of miR-96 in PTC specimens by RT-qPCR and western blot analysis. The data from the present study demonstrated that miR-96 can promote proliferation, and inhibit apoptosis in PTC cell lines K1 and TPC1, thus miR-96 may play an oncogenic role in PTC by inhibiting the FOXO1 and regulating AKT/FOXO1/Bim pathway, and it may serve as a novel therapeutic target for miRNA-based PTC therapy.

miR-99b suppresses IGF-1R expression and contributes to inhibition of cell proliferation in human epidermal keratinocytes

Condyloma acuminatum (CA) is a condition caused by the highly contagious human papillomavirus (HPV), characterized by warts that undergo abnormal cell proliferation. One of the important regulators of cell proliferation is microRNAs (miRNAs). In this study, we aimed to investigate the expression profile of miR-99b in HPV positive CA samples and normal skin. We found significantly lower miR-99b levels in CA samples than in normal skin. Therefore, we investigated the role of miR-99b in regulating the proliferation of primary cultured human epidermal keratinocytes, and found that forced expression of miR-99b inhibited proliferation and induced G1-phase arrest. Based on conserved sequences in 3'UTR for miR-99b binding, we identified the insulin-like growth factor-1 receptor (IGF-1R) gene as a direct target for miR-99b. Further, we confirmed the binding site for miR-99b in the IGF-1R 3'UTR by mutation using a luciferase reporter assay that showed decrease in luciferase activity in the presence of miR-99b in the construct with the wild-type 3'UTR, but not in the construct with the mutant 3'UTR. Moreover, miR-99b over-expression could down-regulate IGF-1R expression, and could repress the PI3K-AKT signaling pathway. Lastly, over-expression of IGF-1R reversed the inhibitory effect of miR-99b on keratinocyte proliferation. Taken together, our results suggest that IGF-1R levels may be modulated by miR-99b in CA: downregulation of miR-99b with concomitant upregulation of its target gene IGF-1R may over-induce the PI3K-AKT signaling pathway, leading to deregulated cell proliferation in CA.

MicroRNAs in Cancer: A Historical Perspective on the Path from Discovery to Therapy

Recent progress in microRNA (miRNA) therapeutics has been strongly dependent on multiple seminal discoveries in the area of miRNA biology during the past two decades. In this review, we focus on the historical discoveries that collectively led to transitioning miRNAs into the clinic. We highlight the pivotal studies that identified the first miRNAs in Caenorhabditis elegans to the more recent reports that have fueled the quest to understand the use of miRNAs as markers for cancer diagnosis and prognosis. In addition, we provide insights as to how unraveling basic miRNA biology has provided a solid foundation for advancing miRNAs, such as miR-34a, therapeutically. We conclude with a brief examination of the current challenges that still need to be addressed to accelerate the path of miRNAs to the clinic: including delivery vehicles, miRNA- and delivery-associated toxicity, dosage, and off target effects.