The emerging role of microRNAs in resistance to lung cancer treatments

Non-Coding RNA as a Biomarker in Lung Cancer

INTRODUCTION

Lung cancer remains one of the most prevalent and deadly cancers globally, with high mortality rates largely due to late-stage diagnosis, aggressive progression, and frequent recurrence. Despite advancements in diagnostic techniques and therapeutic interventions, the overall prognosis for lung cancer patients continues to be dismal.

METHOD

Emerging research has identified non-coding RNAs (ncRNAs), including microRNAs, long non-coding RNAs, and circular RNAs, as critical regulators of gene expression, significantly influencing cancer biology. These ncRNAs play pivotal roles in various aspects of lung cancer pathogenesis, including tumor initiation, progression, metastasis, and resistance to therapy.

RESULTS

We provide a comprehensive analysis of the current understanding of ncRNAs in lung cancer, emphasizing their potential as biomarkers for early diagnosis, prognostication, and the prediction of the therapeutic response. We explore the biological functions of ncRNAs, their involvement in key oncogenic pathways, and the molecular mechanisms by which they modulate gene expression and cellular processes in lung cancer. Furthermore, this review highlights recent advances in ncRNA-based diagnostic tools and therapeutic strategies, such as miRNA mimics and inhibitors, lncRNA-targeted therapies, and circRNA-modulating approaches, offering promising avenues for personalized medicine.

CONCLUSION

Finally, we discuss the challenges and future directions in ncRNA research, including the need for large-scale validation studies and the development of efficient delivery systems for ncRNA-based therapies. This review underscores the potential of ncRNAs to revolutionize lung cancer management by providing novel diagnostic and therapeutic options that could improve patient outcomes.

The interplay between microRNAs and Nrf2 signaling in human cancers

MicroRNAs (miRNAs), as a class of nonprotein-coding RNAs, post-transcriptionally regulate the expression of target genes by base pairing to 3'-untranslated regions (3'-UTRs). Nuclear factor E2-related factor 2 (Nrf2) has been identified as a critical component of the antioxidant defense mechanism. Dysregulation is associated with chemoresistance and radioresistance in cancerous cells. MiRNA-mediated regulation of the Nrf2 signaling pathway has been shown to have important implications for the development of various cancers. In this article, we review the roles of miRNAs as regulators of the Nrf2 pathway in different human cancers. Ras-associated binding (Rab) proteins have an essential role regulation of vesicle transport, as well as oncogenic functions in preventing chemotherapy efficacy and cancer development. More importantly, increased evidence indicated that the interaction between miRNAs and Rabs has been determined to play critical roles in cancer therapy. However, the significant limitations in using miRNAs for therapeutic applications include cross-targeting and instability of miRNAs. The detailed aspect of the interaction of miRNAs and Rabs is not clearly understood. In the current review, we highlighted the involvement of these molecules as regulators of the Nrf2 pathway in cancer pathogenesis. Potential methods and several obstacles in developing miRNAs as an anticancer therapy are also mentioned.

Unravelling the Role of Cancer Cell-Derived Extracellular Vesicles in Muscle Atrophy, Lipolysis, and Cancer-Associated Cachexia

Cancer-associated cachexia is a metabolic syndrome that causes significant reduction in whole-body weight due to excessive loss of muscle mass accompanied by loss of fat mass. Reduced food intake and several metabolic abnormalities, such as increased energy expenditure, excessive catabolism, and inflammation, are known to drive cachexia. It is well documented that cancer cells secrete EVs in abundance which can be easily taken up by the recipient cell. The cargo biomolecules carried by the EVs have the potential to alter the signalling pathways and function of the recipient cells. EV cargo includes proteins, nucleic acids, lipids, and metabolites. Tumour-secreted EVs have been found to alter the metabolic and biological functions of adipose and muscle tissue, which aids in the development of the cachexia phenotype. To date, no medical intervention or FDA-approved drug exists that can completely reverse cachexia. Therefore, understanding how cancer-derived EVs contribute to the onset and progression of cancer-associated cachexia may help with the identification of new biomarkers as well as provide access to novel treatment alternatives. The goal of this review article is to discuss the most recent research on cancer-derived EVs and their function in cellular crosstalk that promotes catabolism in muscle and adipose tissue during cancer-induced cachexia.

A miR-15a related polymorphism affects NSCLC prognosis via altering ERCC1 repair to platinum-based chemotherapy

Platinum‐based chemotherapy is regarded as a preferential curative‐intent option for non‐small cell lung cancer (NSCLC), while the acquired drug resistance has become a major obstacle that limits its clinical application. Since the repair efficiency of tumour cells to platinum‐DNA adducts plays a crucial role in chemotherapy resistance, we aimed to explore whether several meaningful polymorphisms of DNA repair genes were associated with the benefits of platinum‐based chemotherapy in NSCLC patients. Firstly, six single nucleotide polymorphisms (SNPs) located in the 3'untranslated region (3'UTR) of three DNA repair genes were detected in 246 NSCLC patients receiving platinum‐based chemotherapy and analysed the correlation of these candidate SNPs with the overall survival. Cox proportional hazard model showed that NSCLC patients carrying ERCC1 rs3212986 AA genotype had a shorter overall survival compared to those with CC. Mechanistically, we performed tumour chemosensitivity assay to observe the convincing linkage of rs3212986 polymorphism with ERCC1 expression and cisplatin sensitivity. The subsequent in vitro experiments identified that rs3212986 polymorphism altered the post‐transcriptional regulation of ERCC1 via affecting the binding of miR‐15a, and further changed the sensitivity to platinum analogue. It reminded that patients carrying ERCC1 rs3212986 CC homozygote were expected to respond better to platinum‐based chemotherapy due to a lower expression of ERCC1. Compared with previous studies, our current comprehensive study suggested that rs3212986, a 3'UTR polymorphism in ERCC1, might have clinical relevance in predicting the prognosis of NSCLC patients receiving platinum‐based chemotherapy.

Current Landscape of Therapeutic Resistance in Lung Cancer and Promising Strategies to Overcome Resistance

Lung cancer is one of the leading causes of cancer-related deaths worldwide with a 5-year survival rate of less than 18%. Current treatment modalities include surgery, chemotherapy, radiation therapy, targeted therapy, and immunotherapy. Despite advances in therapeutic options, resistance to therapy remains a major obstacle to the effectiveness of long-term treatment, eventually leading to therapeutic insensitivity, poor progression-free survival, and disease relapse. Resistance mechanisms stem from genetic mutations and/or epigenetic changes, unregulated drug efflux, tumor hypoxia, alterations in the tumor microenvironment, and several other cellular and molecular alterations. A better understanding of these mechanisms is crucial for targeting factors involved in therapeutic resistance, establishing novel antitumor targets, and developing therapeutic strategies to resensitize cancer cells towards treatment. In this review, we summarize diverse mechanisms driving resistance to chemotherapy, radiotherapy, targeted therapy, and immunotherapy, and promising strategies to help overcome this therapeutic resistance.

Tumor Targeted Polymer Nanoparticles Co-loaded with Docetaxel and siCCAT2 for Combination Therapy of Lung Cancer

Multi-drug resistance (MDR) is the major hindrances toward the successful treatment of malignant lung cancer. The aim of this study was to develop a novel nanoparticle co-loaded with docetaxel (DTX) and si-colon cancer-associated transcript-2 (siCCAT2) (NP-DTX/siCCAT2) for overcoming the DTX-resistant non-small cell lung cancer (NSCLC). The NP-DTX/siCCAT2, developed by DTX-conjugated poly (D,L-lactic-co-glycolic acid) (PLGA) copolymers, has an average size of t 87.26 nm. Further modification of Transferrin (Tf) peptides on the surface of NP-DTX/siCCAT2 did not significantly change the particle size with an average diameter of 96.81 nm. The present study demonstrated that TfNP-DTX/siCCAT2 has excellent tumor targeting ability and resulted in an enhanced anti-tumor effect both in vitro and in vivo experiments. Not unexpectedly, more excellent anti-tumor effect of NP-DTX/siCCAT2 was obtained than the NP-DTX because of that that silencing of CCAT2 levels in lung cancer cells resulted in down-regulated expressions of P-glycoprotein (P-gp) and multidrug-resistance-associated proteins 1 (MRP1). Further investigation revealed that inhibition of CCAT2 expression dramatically increased the activity of miR-204-3p and thereby signally suppressed the IGFBP2/AKT/Bcl2 pathway.

Cell Behavior of Non-Small Cell Lung Cancer Is at EGFR and MicroRNAs Hands

Lung cancer is a complex disease associated with gene mutations, particularly mutations of Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) and epidermal growth factor receptor (EGFR). Non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) are the two major types of lung cancer. The former includes most lung cancers (85%) and are commonly associated with EGFR mutations. Several EGFR-tyrosine kinase inhibitors (EGFR-TKIs), including erlotinib, gefitinib, and osimertinib, are effective therapeutic agents in EGFR-mutated NSCLC. However, their effectiveness is limited by the development (acquired) or presence of intrinsic drug resistance. MicroRNAs (miRNAs) are key gene regulators that play a profound role in the development and outcomes for NSCLC via their role as oncogenes or oncosuppressors. The regulatory role of miRNA-dependent EGFR crosstalk depends on EGFR signaling pathway, including Rat Sarcoma/Rapidly Accelerated Fibrosarcoma/Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase 1/2 (Ras/Raf/MEK/ERK1/2), Signal Transducer and Activator of Transcription (STAT), Nuclear Factor Kappa-Light-Chain-Enhancer of Activated B Cells (NF-kB), phosphoinositide 3-kinase/protein kinase B (PI3K/AKT), Janus kinase 1 (JAK1), and growth factor receptor-bound protein 2 (GRB2). Dysregulated expression of miRNAs affects sensitivity to treatment with EGFR-TKIs. Thus, abnormalities in miRNA-dependent EGFR crosstalk can be used as diagnostic and prognostic markers, as well as therapeutic targets in NSCLC. In this review, we present an overview of miRNA-dependent EGFR expression regulation, which modulates the behavior and progression of NSCLC.

Combination of two miRNAs has a stronger effect on stimulating apoptosis, inhibiting cell growth, and increasing erlotinib sensitivity relative to single miRNA in A549 lung cancer cells

Despite the dramatic efficacy of EGFR-TKIs, most of non-small cell lung cancer patients ultimately develop resistance to these agents. In this study, we explored the effects of miRNA-125a-5p and miRNA-145, alone or in combination, EGFR expression, cell growth and sensitivity of the NSCLC cells to erlotinib. The expression of EGFR was measured using RT-qPCR and Western blotting. The effect of miRNAs and erlotinib on cell growth and survival was assessed by trypan blue assay and MTT assay, respectively. Apoptosis was measured using ELISA cell death assay. We found that transfection of miRNA-125a-5p and miRNA-145 significantly inhibited the expression of EGFR mRNA and protein in a time-dependent manner (p < 0.05 vs. blank control or negative control miRNA). ANOVA and Bonferroni's test were used to ascertain significant differences between groups. Other experiments indicated that upregulation of each of miRNA-125a-5p or miRNA-145 inhibited cell growth, induced apoptosis, and markedly decreased the IC₅₀ value of erlotinib in A549 lung cancer cells (p < 0.05). Moreover, the combination of two miRNAs showed a stronger effect on cells survival, apoptosis, and drug sensitivity, relative to single miRNA (p < 0.05). The results of our study indicate that the therapeutic delivery of miRNA-145 and miRNA-125a-5p to lung cancer may inhibit cell proliferation, trigger apoptosis, and sensitize lung cancer cells to EGFR-TKIs.

Oncogenesis and Tumor Inhibition by MicroRNAs and its Potential Therapeutic Applications: A Systematic Review

MicroRNAs appear as small molecule modifiers, which improve many new findings and mechanical illustrations for critically important biological phenomena and pathologic events. The best-characterized non-coding RNA family consists of about 2600 human microRNAs. Rich evidence has revealed their crucial importance in maintaining normal development, differentiation, growth control, aging, modulation of cell survival or apoptosis, as well as migration and metastasis as microRNAs dysregulation leads to cancer incidence and progression. By far, microRNAs have recently emerged as attractive targets for therapeutic intervention. The rationale for developing microRNA therapeutics is based on the premise that aberrantly expressed microRNAs play a significant role in the emergence of a variety of human diseases ranging from cardiovascular defects to cancer, and that repairing these microRNA deficiencies by either antagonizing or restoring microRNA function may yield a therapeutic benefit. Although microRNA antagonists are conceptually similar to other inhibitory therapies, improving the performance of microRNAs by microRNA replacement or inhibition that is a less well- described attitude. In this assay, we have condensed the last global knowledge and concepts regarding the involvement of microRNAs in cancer emergence, which has been achieved from the previous studies, consisting of the regulation of key cancer-related pathways, such as cell cycle control and the DNA damage response and the disruption of profile expression in human cancer. Here, we have reviewed the special characteristics of microRNA replacement and inhibition therapies and discussed explorations linked with the delivery of microRNA mimics in turmeric cells. Besides, the achievement of biomarkers based on microRNAs in clinics is considered as novel non-invasive biomarkers in diagnostic and prognostic assessments.

Bioinformatics analysis of mRNA and miRNA microarray to identify the key miRNA-mRNA pairs in cisplatin-resistant ovarian cancer

Background

Ovarian cancer (OC) is a gynecological malignancy with the highest mortality rate. Cisplatin (DDP) based chemotherapy is a standard strategy for ovarian cancer. Despite good response rates for initial chemotherapy, almost 80% of the patients treated with DDP based chemotherapy will experience recurrence due to drug-resistant, which will ultimately result in fatality. The aim of the present study was to examine the pathogenesis and potential molecular markers of cisplatin-resistant OC by studying the differential expression of mRNAs and miRNAs between cisplatin resistant OC cell lines and normal cell lines.

Methods

Two mRNA datasets (GSE58470 and GSE45553) and two miRNA sequence datasets (GSE58469 and GSE148251) were downloaded from the Gene expression omnibus (GEO) database. Differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) were screened by the NetworkAnalyst. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted to analyze the biological functions of DEGs. The protein-protein interaction network was constructed using STRING and Cytoscape software to identify the molecular mechanisms of key signaling pathways and cellular activities. FunRich and MiRNATip databases were used to identify the target genes of the DEMs.

Results

A total of 380 DEGs, and 5 DEMs were identified. Protein–protein interaction (PPI) network of DEGs containing 379 nodes and 1049 edges was constructed, and 4 key modules and 24 hub genes related to cisplatin-resistant OC were screened. Two hundred ninety-nine target genes of the 5 DEMs were found out. Subsequently, one of these 299 target genes (UBB) belonging to the hub genes of GSE58470 and GSE45553 was identified by MCODE and CytoHubba,which was regulated by one miRNA (mir-454).

Conclusions

One miRNA–mRNA regulatory pairs (mir-454-UBB) was established. Taken together, our study provided evidence concerning the alteration genes involved in cisplatin-resistant OC, which will help to unravel the mechanisms underlying drug resistant.

MicroRNA expression profiling and biomarker validation in treatment-naïve and drug resistant non-small cell lung cancer

Background

In the absence of targetable mutations or immune checkpoints, cisplatin-doublet chemotherapy remains the standard of care in non-small cell lung cancer (NSCLC). Drug resistance has however become a significant clinical challenge. Exploring a role for small non-coding microRNAs (miRNA) as biomarker candidates in cisplatin resistant (CisR) lung cancer is lacking and warrants further investigation.

Methods

miRNA expression profiling was assessed in a panel of cisplatin sensitive and resistant NSCLC cell lines and validated by qPCR. Modulation of altered miRNAs was studied using antagomiRs and pre-miRs while functional assays were used to assess cisplatin response. The translational relevance of these miRNAs as potential biomarkers was assessed in serum and matched normal and tumour lung tissues from chemo-naïve NSCLC patients, in addition to xenograft formalin-fixed paraffin-embedded (FFPE) tumours derived from cisplatin sensitive and resistant cell lines.

Results

Differential expression of a 5-miR signature (miR-30a-3p, miR-30b-5p, miR-30c-5p, miR-34a-5p, miR-4286) demonstrated their ability to distinguish between normal and tumour lung tissue and between NSCLC histologies. In squamous cell carcinoma (SqCC), tissue miRNA expression was associated with poor survival. miR-4286 showed promise as a blood-based diagnostic biomarker that could distinguish between adenocarcinoma and SqCC histologies. In a xenograft model of cisplatin resistance, using 7-9 week old female NOD/SCID mice (NOD.CB17-Prkdcscid/NCrCrl), a 5-miRNA panel showed altered expression between sensitive and resistant tumours.

Conclusions

This study identified a panel of miRNAs which may have diagnostic and prognostic potential as novel biomarkers in lung cancer and furthermore, may have a predictive role in monitoring the emergence of resistance to cisplatin.

Circulating Exosomal miR-96 as a Novel Biomarker for Radioresistant Non-Small-Cell Lung Cancer

Patients with non-small-cell lung cancer (NSCLC) frequently develop radioresistance, resulting in poor response to radiation and unfavourable prognosis. Early detection of radioresistance hence can guide the adjustment of treatment regimens in time. Exosomes are lipid bilayer-enclosed vesicles with sub-micrometer size that are released by various cells. Exosomes contain a tissue-specific signature wherein a variety of proteins and nucleic acids are selectively packaged. Growing evidence shows exosomes are involved in cancer pathophysiology and exosomes as the latest addition to the liquid biopsy portfolio have been used in cancer diagnosis. Compared to cell free RNA, exosomal lipid envelope can effectively protect RNA cargo against degradation. Therefore, exosomes may hold great promise for the identification of radioresistance. Here, we report six plasma exosomal miRNAs could be used to distinguish radioresistant NSCLC patients from radiosensitive NSCLC patients and to evaluate the prognosis of NSCLC. Samples were obtained from 52 NSCLC patients with or without radioresistance and 45 age-matched healthy volunteers. Exosomes in 1 ml plasma were isolated followed by extraction of small RNA. The expression levels of miRNAs were determined by quantitative real-time PCR. Potential miRNA markers were further evaluated in additional 52 NSCLC patients. We found exosomal miR-1246 and miR-96 are significantly overexpressed in NSCLC patients. Moreover, exosomal miR-96 in patients with radioresistant NSCLC is significantly higher than that of controls. Exosomal miR-96 also demonstrates a significant correlation with vascular invasion and poor overall survival. Altogether, our results indicate that exosomal miR-96 could be a non-invasive diagnostic and prognostic marker of radioresistant NSCLC.

Analysis of deep sequencing exosome-microRNA expression profile derived from CP-II reveals potential role of gga-miRNA-451 in inflammation

Mycoplasma gallisepticum (MG) can cause chronic respiratory disease (CRD) in chickens. While several studies have reported the inflammatory functions of microRNAs during MG infection, the mechanism by which exosomal miRNAs regulate MG-induced inflammation remains to be elucidated. The expression of exosome-microRNA derived from MG-infected chicken type II pneumocytes (CP-II) was screened, and the target genes and function of differentially expressed miRNAs (DEGs) were predicted. To verify the role of exosomal gga-miR-451, Western blot, ELISA and RT-qPCR were used in this study. The results showed that a total of 722 miRNAs were identified from the two exosomal small RNA (sRNA) libraries, and 30 miRNAs (9 up-regulated and 21 down-regulated) were significantly differentially expressed. The target miRNAs were significantly enriched in the treatment group, such as cell cycle, Toll-like receptor signalling pathway and MAPK signalling pathway. The results have also confirmed that gga-miR-451-absent exosomes derived from MG-infected CP-II cells increased inflammatory cytokine production in chicken fibroblast cells (DF-1), and wild-type CP-II cell-derived exosomes displayed protective effects. Collectively, our work suggests that exosomes from MG-infected CP-II cells alter the dynamics of the DF-1 cells, and may contribute to pathology of the MG infection via exosomal gga-miR-451 targeting YWHAZ involving in inflammation.

Gene Therapy with MiRNA-Mediated Targeting of Mcl-1 Promotes the Sensitivity of Non-Small Cell Lung Cancer Cells to Treatment with ABT-737

BACKGROUND

Despite the dramatic efficacy of ABT-737, a large percentage of cancer cells ultimately become resistance to this drug. Evidences show that over-expression of Mcl-1 is linked to ABT-737 resistance in NSCLC cells. The aim of this study was to investigate the effect of miRNA-101 on Mcl-1 expression and sensitivity of the A549 NSCLC cells to ABT-737.

METHODS

After miRNA-101 transfection, the Mcl-1 mRNA expression levels were quantified by RT-qPCR. Trypan blue staining was used to explore the effect of miRNA-101 on cell growth. The cytotoxic effects of miRNA-101 and ABT-737, alone and in combination, were measured using MTT assay. The effect of drugs combination was determined using the method of Chou-Talalay. Cell death was assessed using cell death detection ELISA assay kit.

RESULTS

Results showed that miRNA-101 markedly suppressed the expression of Mcl-1 mRNA in a time dependent manner, which led to A549 cell proliferation inhibition and enhancement of apoptosis (p < 0.05, relative to blank control). Pretreatment with miRNA-101 synergistically decreased the cell survival rate and lowered the IC50 value of ABT-737. Furthermore, miRNA-101 dramatically enhanced the apoptotic effect of ABT-737. Negative control miRNA had no remarkable effect on cellular parameters.

CONCLUSIONS

Our findings propose that suppression of Mcl-1 by miRNA-101 can effectively inhibit the cell growth and sensitize A549 cells to ABT-737. Therefore, miRNA-101 can be considered as a potential therapeutic target in patients with non-small cell lung cancer.
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Non-coding RNAs in Lung Cancer Chemoresistance

Background:

Lung cancer is the leading cause of cancer-associated death worldwide with limited treatment options. The major available treatment options are surgery, radiotherapy, chemotherapy and combinations of these treatments. In chemotherapy, tyrosine kinase inhibitors and taxol are the first lines of chemotherapeutics used for the treatment of lung cancer. Often drug resistance in the clinical settings hinders the efficiency of the treatment and intrigues the tumor relapse. Drug-resistance is triggered either by intrinsic factors or due to the prolonged cycles of chemotherapy as an acquired-resistance. There is an emerging role of non-coding RNAs (ncRNAs), including notorious microRNAs (miRNAs), proposed to be actively involved in the regulations of various tumor-suppressor genes and oncogenes.

Result:

The altered gene expression by miRNA is largely mediated either by the degradation or by interfering with the translation of targeted mRNA. Unlike miRNA, other type of ncRNAs, such as long non-coding RNAs (lncRNAs), can target the transcriptional activator or the repressor, RNA polymerase, and even DNA-duplex to regulate the gene expressions. Many studies have confirmed the crucial role of ncRNAs in lung adenocarcinoma progression and importantly, in the acquisition of chemoresistance. Recently, ncRNAs have become early biomarkers and therapeutic targets for lung cancer.

Conclusion:

Targeting ncRNAs could be an effective approach for the development of novel therapeutics against lung cancer and to overcome the chemoresistance.

Up-Regulation of MiRNA-125a-5p Inhibits Cell Proliferation and Increases EGFR-TKI Induced Apoptosis in Lung Cancer Cells

BACKGROUND

Despite the dramatic efficacy of erlotinib, an EGFR tyrosine kinase inhibitor (TKI), most of non-small cell lung cancer (NSCLC) patients ultimately acquire resistance to this agent. Different studies indicated that miRNA-125a-5p is down-regulated in human lung cancer cells and may function as a tumor suppressor by targeting EGFR. However, the biological function of miRNA-125a-5p in NSCLC resistance to EGFR-TKIs is not fully understood. In this study the effect of miRNA-125a-5p on cell proliferation, apoptosis and sensitivity of the A549 lung cancer cells to erlotinib was investigated.

METHODS

After miRNA-125a-5p transfection, the expression levels of EGFR mRNA were measured by QRT-PCR. Trypan blue assays were performed to evaluate the proliferation of the A549 lung cancer cells. The cytotoxic effects of miRNA-125a-5p and erlotinib, alone and in combination, were determined using MTT assay. Combination index study was performed using the method of Chou-Talalay. Apoptosis was assessed using an ELISA cell death assay kit.

RESULTS

MiRNA-125a-5p clearly reduced the expression of EGFR mRNA in a time dependent manner, causing marked cell proliferation inhibition and spontaneous apoptosis (p<0.05, relative to control). Pretreatment with miRNA-125a-5p synergistically increased the cytotoxic effect of erlotinib and decreased its IC50. Furthermore, miRNA-125a-5p significantly enhanced the apoptotic effect of erlotinib. Negative control miRNA had no significant effect on biological parameter of the tumor cells.

CONCLUSIONS

Our data suggest that suppression of EGFR by miRNA-125a-5p can effectively trigger apoptosis and overcome EGFR-TKs resistance of lung cancer cells. Therefore, miRNA-125a-5p may be a potential therapeutic adjuvant in patients with lung cancer.
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Reciprocal regulation of miR-206 and IL-6/STAT3 pathway mediates IL6-induced gefitinib resistance in EGFR-mutant lung cancer cells

Persistently activated IL‐6/STAT3 pathway promotes acquired resistance to targeted therapy with epidermal growth factor receptor‐tyrosine kinase inhibitors (EGFR‐TKIs) in non–small‐cell lung cancer (NSCLC) treatment. miR‐206 has been verified to be dysregulated and plays as a negative regulator in lung cancer. However, whether miR‐206 may overcome IL6‐induced gefitinib resistance in EGFR‐mutant lung cancer remains elusive. In this study, we investigated the role of miR‐206 in IL6‐induced gefitinib‐resistant EGFR‐mutated lung cancer cell lines. We showed that forced miR‐206 expression restored gefitinib sensitivity in IL6‐induced gefitinib‐resistant EGFR‐mutant lung cancer cells by inhibiting IL6/JAK1/STAT3 pathway. Specifically, mechanistic investigations revealed that miR‐206 blocked IL‐6/STAT3 signalling via directly targeting the 3'‐UTR of intracellular IL‐6 messenger RNA. Moreover, IL‐6 induced miR‐206 down‐regulation by reducing the cropping process of primary miR‐206 (pri‐miR‐206) into the Drosha/DGCR8 complex. Taken together, our findings reveal a direct role of miR‐206 in regulating IL‐6/STAT3 pathway and contrarily activated IL‐6/STAT3 signalling mediates the miR‐206 maturation process in gefitinib‐resistant EGFR‐mutant lung cancer cells.

Targeting Epidermal Growth Factor Receptor by MiRNA-145 Inhibits Cell Growth and Sensitizes NSCLC Cells to Erlotinib

Background: Despite effective activity of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), such as erlotinib, all non-small cell lung cancer (NSCLC) patients eventually acquire resistance to these agents. Studies have demonstrated that down-regulation of miRNA-145 leads to enhancement of EGFR expression, cell proliferation and metastasis. The aim of this study was to investigate the effect of miRNA-145 on sensitivity of the A549 NSCLC cells to erlotinib. Methods: Quantitative real-time PCR was used to examine the effect of miRNA-145 on EGFR expression. The effect of miRNA-145 on cell growth and sensitivity the lung cancer cells to erlotinib was examined by trypan blue and MTT assays, respectively. The combination index was calculated using the non-constant method of Chou-Talalay. Apoptosis was determined by ELISA cell death assay. Results: We found that miRNA-145 was markedly suppressed the expression of EGFR and inhibited the cancer cell growth, relative to blank control and negative control miRNA (p<0.05). Pretreatment with miRNA-145 synergistically enhanced the sensitivity of the lung cancer cells to erlotinib. Results of apoptosis assay revealed that miRNA-145 can induce apoptosis and increase the erlotinib-mediated apoptosis. Conclusions: Our data demonstrate that miRNA-145 play a critical role in the lung cancer cell growth, survival and EGFR-TKIs resistance possibly by regulation of EGFR. Therefore, miRNA-145 replacement therapy can become a new therapeutic strategy in lung cancer.

Identification of differentially expressed MiRNAs profile in a thiram-induced tibial dyschondroplasia

Tetramethyl thiuram disulfide (thiram) is a dithiocarbamate, which is widely used on seeds and storing food grains. The incorporation of thiram into the food chain could be a risk for both human beings and animals. Thiram-contaminated feed has been considered a common cause of tibial dyschondrolplasia (TD) in many avian species. The molecular mechanism of action of thiram on TD involving microRNA (miRNA) is not fully understood. For this purpose, the morbidity and pathologic changes were evaluated to understand the TD, and high-throughput RNA sequencing (RNA-Seq) was performed to explore the differentially expressed miRNAs (DEGs). RT-qPCR was used to confirm the validity as compared with sequencing data. The results showed that the marked alterations in the growth plate of the TD chickens were noticeable, with shrinking cells and irregular chondrocyte columns as compared with control group. In this study, we identified total 375 (p < 0.1), 340 (p < 0.05) and 266 (p < 0.01) significant DEGs between the TD and control groups. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of DEGs showed that the target miRNAs were significantly enriched in different treatment groups, such as apoptosis, mRNA surveillance pathway, mitophagy-animal, etc. This study provides theoretical basis for in-depth understanding the pathogenesis of thiram-induced TD and explore the new insights towards the proposed molecular mechanism of specific miRNA as biomarkers for effective gene diagnosis and treatment of TD in broilers.

Circulating miR-30b and miR-30c predict erlotinib response in EGFR-mutated non-small cell lung cancer patients

OBJECTIVES

MiR-30b, miR-30c, miR-221 and miR-222 are known to induce gefitinib resistance in lung cancer cell lines with activation of mutations in the epidermal growth factor receptor (EGFR). However, the role of these four microRNAs in tyrosine kinase inhibitor (TKI)-resistance in non-small cell lung cancer (NSCLC) patients is unknown. Thus, the aim of this study was to investigate the predictive value of miR-30b, miR-30c, miR-221 and miR-222 in plasma from EGFR-mutated lung cancer patients receiving erlotinib.

MATERIALS AND METHODS

The cohort consisted of 29 EGFR-mutated lung cancer patients receiving erlotinib. Plasma levels of miR-30b, miR-30c, miR-221 and miR-222 were analyzed by qPCR from blood samples collected before treatment start. Plasma concentration of each microRNA was correlated to clinical outcome.

RESULTS

Plasma concentrations of miR-30b and miR-30c could be determined in all 29 patients. Low plasma concentrations of miR-30b and miR-30c showed significant correlation with superior progression-free survival (PFS) (miR-30b: HR = 0.303 [0.123-0.747], p < 0.05; miR-30c: HR = 0.264 [0.103-0.674], p < 0.05). Low plasma concentrations of miR-30c were also significantly correlated with superior overall survival (OS) (HR = 0.30 [0.094-0.954], p < 0.041).

CONCLUSION

High plasma concentrations of miR-30b and miR-30c predicted shorter PFS and OS. This implies that miR-30b and miR-30c could have clinical potential as biomarkers in EGFR-mutated lung cancer patients.

The targeting of non‑coding RNAs by curcumin: Facts and hopes for cancer therapy (Review)

Curcumin [(1E,6E)‑1,7‑bis(4‑hydroxy‑3‑-methoxyphenyl) hepta‑1,6‑diene‑3,5‑dione] is a natural polyphenol that is derived from the turmeric plant (curcuma longa L.). Curcumin is widely used in food coloring, preservatives, and condiments. Curcumin possesses anti‑tumor, anti‑oxidative and anti‑inflammatory efficacy, as well as other pharmacological effects. Emerging evidence indicates that curcumin alters microRNAs (miRNAs) and long non‑coding RNAs (lncRNAs) in various types of cancers. Both miRNAs and lncRNAs are non‑coding RNAs that can epigenetically modulate the expression of multiple genes via post‑transcriptional regulation. In the present review, the interactions between curcumin and non‑coding RNAs are summarized in numerous types of cancers, including lung, colorectal, prostate, breast, nasopharyngeal, pancreatic, blood, and ovarian cancer, and the vital non‑coding RNAs and their downstream targets are described.

Decision tree-based classifiers for lung cancer diagnosis and subtyping using TCGA miRNA expression data

Lung cancer has the world's highest cancer- associated mortality rate, making biomarker discovery for this cancer a pressing issue. Machine learning approaches to identify molecular biomarkers are not as prevalent as screening of potential biomarkers by differential expression analysis. However, several differentially expressed miRNAs involved in cancer have been identified using this approach. The availability of The Cancer Genome Atlas (TCGA) allows the use of machine-learning methods for the molecular profiling of tumors. The present study employed empirical negative control microRNAs (miRs) in lung cancer to normalize lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) datasets from TCGA to model decision trees in order to classify lung cancer status and subtype. The two primary classification models consisted of four miRNAs for lung cancer diagnosis and subtyping. hsa-miR-183 and hsa-miR-135b were used to distinguish lung tumors from normal samples taken from tissues adjacent to the tumor site, and hsa-miR-944 and hsa-miR-205 to further classify the tumors into LUAD and LUSC major subtypes. Specific cancer status classification models were also presented for each subtype.

miR-1915-3p inhibits Bcl-2 expression in the development of gastric cancer

Many gene expressions changed during the development of gastric cancer, and non-coding RNAs including microRNAs (miRNAs) have been found to regulate cancer progression by participating in the process of tumor cell growth, migration, invasion and apoptosis. Our previous study has identified 29 miRNAs that are highly expressed in gastric cancer stem cells. One of these miRNAs, miR-1915-3p, has shown great potential as a diagnostic and prognostic biomarker for the cancers in liver, colon and thyroid, as well as in immune and kidney diseases. Herein, we found that miR-1915-3p exhibited low expression level in differentiated gastric cancer cell lines and gastric cancer tissues. It was found that the miR-1915-3p inhibited the growth of gastric cancer cells and thus promoted cell apoptosis. We discovered that the expressions of miR-1915-3p were significantly correlated to the lymph node metastasis and overall survival of patients with gastric cancer. Further study showed that there was a negative correlation between miR-1915-3p and Bcl-2 (B cell lymphoma/leukemia-2) expression, suggesting that Bcl-2 was a target gene of miR-1915-3p. Hence, miR-1915-3p possibly contributes to the development and progression of gastric cancer by inhibiting the anti-apoptotic protein Bcl-2. The finding provides a potential therapeutic strategy for gastric cancer.

microRNAs: New prognostic, diagnostic, and therapeutic biomarkers in cervical cancer

Cervical cancer is as a kind of cancer beginning from the cervix. Given that cervical cancer could be observed in women who infected with papillomavirus, regular oral contraceptives, and multiple pregnancies. Early detection of cervical cancer is one of the most important aspects of the therapy of this malignancy. Despite several efforts, finding and developing new biomarkers for cervical cancer diagnosis are required. Among various prognostic, diagnostic, and therapeutic biomarkers, miRNA have been emerged as powerful biomarkers for detection, treatment, and monitoring of response to therapy in cervical cancer. Here, we summarized various miRNAs as an employable platform for prognostic, diagnostic, and therapeutic biomarkers in the treatment of cervical cancer.

Encapsulated miR-200c and Nkx2.1 in a nuclear/mitochondria transcriptional regulatory network of non-metastatic and metastatic lung cancer cells

BACKGROUND

MicroRNAs are noncoding RNA molecules of ~ 22 nucleotides with diagnostic and therapeutic action [Curr Drug Targets, 2015. 16(12): p. 1381-403], affecting the expression of mRNAs involved in invasion, migration, and development [Oncotarget, 2015. 6(9): p. 6472-98, Cancer Manag Res, 2014. 6: p. 205-16]. miR-200c is part of the miR-200c/141 cluster on chromosome 12p13. Its mechanism of action when encapsulated is critical in lung cancer when patients express changes in miRNAs. miR-200c be a potential biomarkers for various lung diseases. As a potential therapy, miR-200c can impacts lives as target lung cancer is a leading cause of death with about 234,000 cases annually, high heterogeneity, complex screening, and a 5-year survival rate of 16% [CA Cancer J Clin, 2016.66(1): p. 7-30]. Encapsulated miR-200c efficiently enhances bioavailability, pharmacokinetics of therapeutics and targeting to cells, improves efficacy and provides potential cure.

METHODS

The functions of miR-200c were determined in non-metastatic KW-634 and metastatic 821-T4 and 821-LN mouse lung cancer cell lines after various Nano vehicle treatments. Viability and cytotoxicity were determined by cell cycle and quantitative real-time PCR analyses were used to quantify levels of miR-200c and its target genes. In situ hybridization was used to visualize patterns of expression of miR-200c and others in the lung and many organs. Next-generation sequencing accession number GSE125000, invasion and migration assays using transwell chambers, and ActivSignal were used to elucidate the activation and inhibition profiles and perform direct expression measurements and modification of cellular components.

RESULTS

Due to their effectiveness as intracellular vesicles transporting miR-200c into, out, and between parts of the cells, miR-200c is encapsulated with cholesterol, an integral part of the biological membranes with very important physical properties of the vehicle. Nano miR-200c showed efficient cellular uptake in KW-634, 821-T4, and 821-LN cells with important changes in gene expression and new isoforms. In KW-634, when treated with encapsulated miR-200c and compare to the non-encapsulated control; miR-29b increased by 5261-fold, and in 821-T4/LN, miR-1247 increased by 150-fold. Conversely, miR-1247 and miR-675 decreased by 348 and 1029.5-fold, respectively. miR-189 decreased by 34-fold in treated 821-T4 cells. A reduction of growth was observed only after 48 h of treatment with Nano miR-200c. Moreover, labeling the vehicle with carboxy-fluorescein showed that the encapsulated particles enter the nucleus and mitochondria. Encapsulated miR-200c by entering the cells, the nucleus and mitochondria, trigger changes in cell cycle phases with 4 up to 12 fold percentage in G2 and S phase respectively compare to miR-200c. Endogenous expression of Nkx2.1, miR-200c, and their targets Myb, Nfib, Six4 and Six1 showed an inverse correlation, as observed in development.

CONCLUSIONS

Little is known about miR-200c involvement in regulatory processes. Nano miR-200c affects invasion and migration mechanisms. The expression of encapsulated miR-200c contributes to the inhibition/activation of Kras, EMT, Hippo, regulatory pathways and blockers of metastasis. Delivery of miR-200c increases the expression of miR-29b, an EMY regulator, and miR-1247, an inhibitor of cancer genes, both tumor suppressors involved in lung metastasis. Encapsulated miR-200c act on different proteins that regulates cell cycle pathways. These findings represent a part of a regulatory network providing new insights towards improvement of therapy.

MiR-384 induces apoptosis and autophagy of non-small cell lung cancer cells through the negative regulation of Collagen α-1(X) chain gene

The present study aims to investigate the mechanism of miR-384 in non-small cell lung cancer (NSCLC) cell apoptosis and autophagy by regulating Collagen α-1(X) chain (COL10A1). Bioinformatics methods were applied to evaluate potential miRNAs and genes that might correlate with NSCLC. Tumor tissues and adjacent tissues from 104 NSCLC patients were collected and human NSCLC A549 cell line was selected for subsequent experiments. A549 cells were treated with miR-384 mimic, miR-384 inhibitor, or knockdown of COL10A1. Quantitative real-time PCR (qRT-PCR) and Western blotting were utilized to detect the levels of miR-384, COL10A, Survivin, Bcl-2, Bax, Bcl-xl, Beclin 1, and LC3 in tissues and cells. A series of biological assays including MTT assay, Annexin V-FITC/PI (propidium iodide) staining, immunofluorescence, monodansylcadaverine (MDC) staining were conducted to investigate the effects of miR-384 and COL10A1 on NSCLC cells. Tumorigenicity assay for nude rats was applied. Results obtained from the present study indicated that miR-384 down-regulated COL10A1 by targetting it. Compared with adjacent tissues, miR-384 expression was obviously reduced while COL10A1 expression was significantly enhanced in NSCLC tissues (all P<0.05). Outcomes in vivo and in vitro suggested that cell proliferation and tumorigenicity were inhibited while cell apoptosis and autophagy were induced in NSCLC cells treated with up-regulation of miR-384 or silence of COL10A1. In miR-384 inhibitor group, cell proliferation was improved, while cell apoptosis was reduced and cell autophagy was decreased whereas tumorigenicity of cells was strengthened. Based on the findings of our study, it was established that miR-384 could down-regulate COL10A1 levels, subsequently inhibiting cell proliferation and promoting cell apoptosis and autophagy in NSCLC cells.

miR-124 and miR-142 enhance cisplatin sensitivity of non-small cell lung cancer cells through repressing autophagy via directly targeting SIRT1

Background: Drug resistance is a major obstacle in the treatment of non-small cell lung cancer (NSCLC). Recently, miRNAs are reported to be involved in the drug resistance of NSCLC. The roles of miR-124 and miR-142 in the multidrug resistance of NSCLC cells have been reported. However, the underlying mechanism by which miR-124 and miR-142 regulate resistance to cisplatin (CDDP) remains unknown. Methods: The expressions of miR-124, miR-142 and sirtuin 1 (SIRT1) in CDDP-sensitive and CDDP-resistant NSCLC tissues and cells were detected by qRT-PCR and western blot. IC50 value and cell proliferation were determined by MTT assay. Apoptosis was assessed by flow cytometry analysis. Autophagy was evaluated by western blot analysis of the protein levels of LC3-I, LC3-II and p62, and FITC-LC3 punctate formation assay. The interaction between miR-124 or miR-142 and SIRT1 was determined by luciferase reporter, RNA immunoprecipitation (RIP) and western blot assays. A tumor xenograft was performed to further validate the role of miR-124 and miR-142 in the sensitivity of CDDP-resistant NSCLC to cisplatin. Results: miR-124 and miR-142 were downregulated, while SIRT1 was upregulated in CDDP-resistant NSCLC tissues and cells compared to CDDP-sensitive groups. Functionally, overexpression of miR-124 and miR-142 or SIRT1 silencing enhanced the CDDP sensitivity of H1299/CDDP cells via suppressing autophagy, as evidenced by the reduced LC3-II/LC3-I radio, elevated p62 protein, and suppressed FITC-LC3 punctate formation in H1299/CDDP cells. miR-124 and miR-142 were demonstrated to co-target SIRT1. Re-expression of SIRT1 overturned miR-124 and miR-142-mediated chemosensitivity in H1299/CDDP cells via triggering autophagy. Conclusion: miR-124 and miR-142 enhance the cytotoxic effect of CDDP through repressing autophagy via targeting SIRT1 in CDDP-resistant NSCLC cells.

Drug resistance is a major obstacle in the treatment of non-small cell lung cancer (NSCLC).

MicroRNA-29a Functions as a Tumor Suppressor and Increases Cisplatin Sensitivity by Targeting NRAS in Lung Cancer

MicroRNAs have been reported to play an important role in diverse biological processes and progression of various cancers. MicroRNA-29a has been observed to be downregulated in human lung cancer tissues, but the function of microRNA-29a in lung cancer has not been well investigated. In this study, we demonstrated that the expression levels of microRNA-29a were significantly downregulated in 38 pairs of lung cancer tissues when compared to adjacent normal tissues. Overexpression of microRNA-29a inhibited the activity of cell proliferation and colony formation of lung cancer cells, H1299 and A549. Furthermore, microRNA-29a targeted NRAS proto-oncogene in lung cancer cells. In human clinical specimens, NRAS proto-oncogene was highly expressed in human lung cancer tissues compared to normal tissues. More interestingly, microRNA-29a also sensitizes lung cancer cells to cisplatin (CDDP[Please replace “CDDP” with its expansion in the abstract and also provide expansion for the same in its first occurrence in text, if appropriate.]) via its target, NRAS proto-oncogene. Thus, our results in this study demonstrated that microRNA-29a acted as a tumor suppressor microRNA, which indicated potential application of microRNAs for the treatment of human lung cancer in the future.

MiR-34c/SOX9 axis regulates the chemoresistance of ovarian cancer cell to cisplatin-based chemotherapy

Cisplatin (DDP)-based chemotherapy is a standard strategy for ovarian cancer (OC), while chemoresistance remains a major therapeutic challenge. Transcription factor SOX9 has been reported to be associated with tumor cell proliferation, metastasis, and chemoresistance. In the current study, we observed a higher SOX9 expression in OC cell lines; SOX9 overexpression might aggravate the chemoresistance of the OC cell to DDP, whereas its knockdown enhanced the chemoresistance. We screened for candidate microRNAs (miRNAs) which might target SOX9 using online tools and further verified the effect of miR-34c, one of the candidate miRNA that significantly inhibited SOX9 expression, in the regulation of OC cell proliferation and chemoresistance to DDP. Further, we verified the interaction between SOX9 and miR-34c, as well as the involvement of β-catenin signaling in this process. Through the analysis of the correlation between miR-34c expression and the clinical features of patients with OC, we revealed that miR-34c might inhibit OC cell proliferation and chemoresistance to improve the prognosis of patients with OC. Further, the expression of SOX9, β-catenin, and c-Myc in OC tissues was upregulated and inversely correlated with miR-34c expression, indicating that rescuing miR-34c expression, thus to inhibit SOX9, β-catenin, and c-Myc expression presents a promising strategy of reducing the chemoresistance of the OC cell to DDP.

A two-miRNA signature (miR-33a-5p and miR-128-3p) in whole blood as potential biomarker for early diagnosis of lung cancer

MicroRNAs (MiRNAs) have been found to be dysregulated in lung cancer tissues compared to their matched paracancerous tissues. However, the roles of miRNAs in peripheral blood as potential biomarkers for early diagnosis of lung cancer remain poorly understood. Here we found that miR-33a-5p and miR-128-3p were down-regulated in lung cancer tissues and cell lines. The expression levels of miR-33a-5p and miR-128-3p in lung cancer tissues were significantly correlated to TNM stages. MiR-128-3p in lung cancer tissues was also remarkably related to smoking and tumor size. The relative expression levels of miR-33a-5p and miR-128-3p were positively correlated in lung cancer tissues. Notably, miR-33a-5p and miR-128-3p in whole blood of lung cancer patients or early-stage lung cancer patients (TNM stage I-II) were lowly expressed as compared with that in healthy controls. The receiver operating characteristic curve (ROC) analyses revealed higher area under the ROC curve (AUC) values and higher sensitivity/specificity of miR-33a-5p and miR-128-3p alone and in combination were superior to that of traditional tumor markers (CYFR21-1, NSE and CA72-4). Importantly, both miR-33a-5p and miR-128-3p in whole blood were highly stable even under different harsh conditions. The results demonstrate that tumor suppressor miR-33a-5p/miR-128-3p in whole blood can serve as novel biomarkers for the early detection of lung cancer.

Emerging role of extracellular vesicles in mediating cancer cachexia

Cancer cachexia is a multifactorial metabolic syndrome characterized by the rapid loss of skeletal muscle mass with or without the loss of fat mass. Nearly 50-80% of all cancer patients' experience rapid weight loss results in ∼20% of cancer-related deaths. The levels of pro-inflammatory and pro-cachectic factors were significantly up-regulated in cachexia patients when compared with the patients who were without cachexia. It is becoming evident that these factors work synergistically to induce cancer cachexia. Extracellular vesicles (EVs) including exosomes and microvesicles are implicated in cell-cell communication, immune response, tissue repair, epigenetic regulation, and in various diseases including cancer. It has been reported that these EVs regulate cancer progression, metastasis, organotropism and chemoresistance. In recent times, the role of EVs in regulating cancer cachexia is beginning to unravel. The aim of this mini article is to review the recent knowledge gained in the field of EVs and cancer cachexia. Specifically, the role of tumour cell-derived EVs in promoting catabolism in distally located skeletal muscles and adipose tissue will be discussed.

MiRNA Dysregulation in Childhood Hematological Cancer

For decades, cancer biology focused largely on the protein-encoding genes that have clear roles in tumor development or progression: cell-cycle control, apoptotic evasion, genome instability, drug resistance, or signaling pathways that stimulate growth, angiogenesis, or metastasis. MicroRNAs (miRNAs), however, represent one of the more abundant classes of cell modulators in multicellular organisms and largely contribute to regulating gene expression. Many of the ~2500 miRNAs discovered to date in humans regulate vital biological processes, and their aberrant expression results in pathological and malignant outcomes. In this review, we highlight what has been learned about the roles of miRNAs in some of the most common human pediatric leukemias and lymphomas, along with their value as diagnostic/prognostic factors.

MicroRNAs in cancer drug resistance: Basic evidence and clinical applications

Development of drug resistance has considerably limited the efficacy of cancer treatments, including chemotherapy and targeted therapies. Hence, understanding the molecular mechanisms underpinning the innate or the acquired resistance to these therapies is critical to improve drug efficiency and clinical outcomes. Several studies have implicated microRNAs (miRNA) in this process. MiRNAs repress gene expression by specific binding to complementary sequences in the 3' region of target messenger RNAs (mRNAs), followed by target mRNA degradation or blocked translation. By targeting molecules specific to a particular pathway within tumor cells, the new generation of cancer treatment strategies has shown significant advantages over conventional chemotherapy. However, the long-term efficacy of targeted therapies often remains poor, because tumor cells develop resistance to such therapeutics. Targeted therapies often involve monoclonal antibodies (mAbs), such as those blocking the ErB/HER tyrosine kinases, epidermal growth factor receptor (cetuximab) and HER2 (trastuzumab), and those inhibiting vascular endothelial growth factor receptor signaling (e.g., bevacizumab). Even though these are among the most used agents in tumor medicine, clinical response to these drugs is reduced due to the emergence of drug resistance as a result of toxic effects in the tumor microenvironment. Research on different types of human cancers has revealed that aberrant expression of miRNAs promotes resistance to the aforementioned drugs. In this study, we review the mechanisms of tumor cell resistance to mAb therapies and the role of miRNAs therein. Emerging treatment strategies combine therapies using innovative miRNA mimics or antagonizers with conventional approaches to maximize outcomes of patients with cancer.

Hypoxia and Noncoding RNAs in Taxane Resistance

Taxanes are chemotherapeutic drugs employed in the clinic to treat a variety of malignancies. Despite their overall efficacy, cancer cells often display resistance to taxanes. Therefore, new strategies to increase the effectiveness of taxane-based chemotherapeutics are urgently needed. Multiple molecular players are linked to taxane resistance; these include efflux pumps, DNA repair mechanisms, and hypoxia-related pathways. In addition, emerging evidence indicates that both non-coding RNAs and epigenetic effectors might also be implicated in taxane resistance. Here we focus on the causes of taxane resistance, with the aim to envisage an integrated model of the 'taxane resistance phenome'. This model could help the development of novel therapeutic strategies to treat taxane-resistant neoplasms.

Pleiotropic functions of miR107 in cancer networks

MicroRNAs are short regulatory RNAs that posttranscriptionally modulate gene expression and thus play crucial roles in controlling cancer-onset, growth, and progression processes. miR107, a highly conserved microRNA that maps to intron 5 of the PANK1 gene, contributes to the regulation of normal and tumor biological processes. Studies have reported that miR107 has oncogenic or tumor-suppressor functions in different human tumors. The pleiotropic functions of miR107 in various cancers are achieved via its targeting different genes that are involved in tumor proliferation, invasiveness, metastasis, angiogenesis, and chemotherapy-response pathways. The carcinogenicity or cancer-suppressor effects of miR107 occur in a tissue- and cell-specific manner, and the expression level of miR107 can be affected by various factors, including epigenetic and genetic factors, treatment exposure, and daily diet. A comprehensive analysis of the current literature suggests that miR107 functions as a central element in the regulation of cancer networks and can be used as a potential diagnostic and prognostic biomarker and drug target for therapeutic intervention.

miR-133b reverses cisplatin resistance by targeting GSTP1 in cisplatin-resistant lung cancer cells

MicroRNAs play a critical role in chemoresistance and are implicated in various biological and pathological processes of cells. The objective of the present study was to explore the role of miR‑133b and its mechanism in the regulation of cisplatin resistance and tumor progression in cisplatin‑resistant non‑small cell lung cancer (NSCLC) cells. Reverse transcription‑quantitative polymerase chain reaction and western blot assays of the cisplatin‑resistant cell lines A549/DPP and H1299/DDP displayed the reduced expression of miR‑133b and increased expression of glutathione-S-transferase P1 (GSTP1) in the resistant cells compared with the respective parental cell lines A549 and H1299. Cell Counting kit‑8, flow cytometry, colony formation and Transwell migration assays indicated that the overexpression of miR‑133b increased the chemosensitivity to cisplatin and attenuated the proliferation and migration capacities of the cisplatin‑resistant NSCLC cell lines in vitro. A dual‑luciferase reporter assay demonstrated that miR‑133b negatively regulated the expression of GSTP1 by targeting its 3'‑untranslated region. In addition, the knockdown of GSTP1 by transfection with small interfering RNA exerted similar effects on cell chemosensitivity, proliferation and migration as did ectopic miR‑133b expression, in addition to the upregulation of Bax and downregulation of Bcl‑2, survivin and matrix metalloproteinase expression. In conclusion, the present study findings provide the insights that miR‑133b reduces cisplatin resistance and its overexpression contributes to the suppression of the malignant growth and aggressiveness of cisplatin‑resistant NSCLC cells by targeting GSTP1. This could potentially be exploited as a novel therapeutic strategy for the reversal of cisplatin resistance.

Non-coding RNAs as emerging regulators of epithelial to mesenchymal transition in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) remains a major health problem that patients suffer from around the world. The epithelial to mesenchymal transition (EMT) has attractive roles in increasing malignant potential and reducing sensitivity to conventional therapeutics in NSCLC cells. Meanwhile, it is now evident that non-coding RNAs (ncRNAs), primarily microRNAs and long non-coding RNAs contribute to tumorigenesis partially via regulating EMT. This article briefly summarizes current researches about EMT-related ncRNAs in NSCLC and discusses their crucial roles in the complex regulatory network. Also, the authors will show the evidence that ncRNAs not only contribute to cancer cells migration and invasion, but also take charge of the resistance of chemotherapy, radiotherapy and EGFR-TIKs. Then, we will further discuss the potential of inhibition of EMT via manipulating relevant ncRNAs to change our current treatment of NSCLC patients.

Epigenetically Regulated Chromosome 14q32 miRNA Cluster Induces Metastasis and Predicts Poor Prognosis in Lung Adenocarcinoma Patients

Most lung cancer deaths are related to metastases, which indicates the necessity of detecting and inhibiting tumor cell dissemination. Here, we aimed to identify miRNAs involved in metastasis of lung adenocarcinoma as prognostic biomarkers and therapeutic targets. To that end, lymph node metastasis-associated miRNAs were identified in The Cancer Genome Atlas lung adenocarcinoma patient cohort (sequencing data; n = 449) and subsequently validated by qRT-PCR in an independent clinical cohort (n = 108). Overexpression of miRNAs located on chromosome 14q32 was associated with metastasis in lung adenocarcinoma patients. Importantly, Kaplan-Meier analysis and log-rank test revealed that higher expression levels of individual 14q32 miRNAs (mir-539, mir-323b, and mir-487a) associated with worse disease-free survival of never-smoker patients. Epigenetic analysis including DNA methylation microarray data and bisulfite sequencing validation demonstrated that the induction of 14q32 cluster correlated with genomic hypomethylation of the 14q32 locus. CRISPR activation technology, applied for the first time to functionally study the increase of clustered miRNA levels in a coordinated manner, showed that simultaneous overexpression of 14q32 miRNAs promoted tumor cell migratory and invasive properties. Analysis of individual miRNAs by mimic transfection further illustrated that miR-323b-3p, miR-487a-3p, and miR-539-5p significantly contributed to the invasive phenotype through the indirect regulation of different target genes. In conclusion, overexpression of 14q32 miRNAs, associated with the respective genomic hypomethylation, promotes metastasis and correlates with poor patient prognosis in lung adenocarcinoma.Implications: This study points to chromosome 14q32 miRNAs as promising targets to inhibit tumor cell dissemination and to predict patient prognosis in lung adenocarcinoma. Mol Cancer Res; 16(3); 390-402. ©2018 AACR.

TIMP-1 downregulation modulates miR-125a-5p expression and triggers the apoptotic pathway

Matrix metalloproteinases and their natural inhibitors (TIMPs) are important elements in a wide range of oncology settings. Elevated levels of tissue inhibitor of metalloproteinase-1 (TIMP-1) have often been associated with increased tumorigenesis. This has been demonstrated in a number of clinical and experimental models which include breast, gastric, colorectal and non-small cell lung carcinoma (NSCLC). Our earlier studies have identified increased angiogenic activity and aggressive tumor kinetics in TIMP-1 overexpressing H2009 lung adenocarcinoma cells. TIMP-1 overexpression has also been implicated in antiapoptotic responses, inducing a significant upregulation of Bcl-2. These TIMP-1 functions have been shown to be MMP-independent and provide insight into its pleiotropic activities. The current study examines microRNA (miRNA) interactions with this molecule. We have sought to define the relationship between TIMP-1 and miRNA by knocking down TIMP-1 in high TIMP-1 expressing lung adenocarcinoma cell lines. TIMP-1 knockdown resulted in increased expression of miR-125a-5p with a concomitant increase in apoptosis and attenuation of the tumorigenic features of these cells. We have identified TIMP-1 as a bona fide target of miR-125a-5p, and their interaction resulted in an increase in p53 expression. We further corroborated our in vitro data with patient samples, which exhibited an inverse correlation between TIMP-1 and miR-125a-5p expression. Our study lends support to the notion that elevated TIMP-1 levels, which are frequently associated with poor prognosis, cause aberrant modulation of miRNAs.

MicroRNA-122-3p inhibits tumor cell proliferation and induces apoptosis by targeting Forkhead box O in A549 cells

The imbalance between cell proliferation and apoptosis was implicated to serve key roles in cancer pathogenesis. The characteristics of microRNAs (miRNAs/miRs) have attracted much attention in research focusing on cancer pathogenesis in recent years. miR-122-3p has been reported to be associated with a number of disease processes and pathogenesis, including lung cancer. The present study aimed to investigate the association of miR-122-3p expression level with cell proliferation and apoptosis in a lung cancer cell line. A549 cells were transfected with miR-122-3p to interrupt the expression of miR-122-3p. Subsequently, MTT and BrdU assay, and western blot were used to analyze the influence of miR-122-3p on lung cancer cell proliferation, cell viability and its underlying mechanism. The present study revealed that, by targeting p27, overexpression of miR-122-3p inhibited cell proliferation in lung cancer. Furthermore, the cell apoptosis analysis suggested that overexpression of miR-122-3p was able to inhibit cell apoptosis by targeting Forkhead box O. These findings suggest that miR-122-3p may be associated with the pathology and progression of lung cancer and be a new therapeutic target for this disease.

MicroRNAs as regulators of cisplatin-resistance in non-small cell lung carcinomas

With more than 80% of all diagnosed lung cancer cases, non-small cell lung cancer (NSCLC) remains the leading cause of cancer death worldwide. Exact diagnosis is mostly very late and advanced-stage NSCLCs are inoperable at admission. Tailored therapies with tyrosine kinase inhibitors are only available for a minority of patients. Thus, chemotherapy is often the treatment of choice. As first-line chemotherapy for NSCLCs, platinum-based substances (e.g. cisplatin, CDDP) are mainly used. Unfortunately, the positive effects of CDDP are frequently diminished due to development of drug resistance and negative influence of microenvironmental factors like hypoxia. MicroRNAs (miRNAs) are small, non-coding molecules involved in the regulation of gene expression and modification of biological processes like cell proliferation, apoptosis and cell response to chemotherapeutics. Expression of miRNAs is often deregulated in lung cancer compared to corresponding non-malignant tissue. In this review we summarize the present knowledge about the effects of miRNAs on CDDP-resistance in NSCLCs. Further, we focus on miRNAs deregulated by hypoxia, which is an important factor in the development of CDDP-resistance in NSCLCs. This review will contribute to the general understanding of miRNA-regulated biological processes in NSCLC, with special focus on the role of miRNA in CDDP-resistance.

The component formula of Salvia miltiorrhiza and Panax ginseng induces apoptosis and inhibits cell invasion and migration through targeting PTEN in lung cancer cells

Lung cancer still remains the leading cause of cancer-related death worldwide. It is an urgent need for development of novel therapeutic agents to improve current treatment of this disease. Here we investigate whether the effective component formula of traditional Chinese Medicine could serve as new potential therapeutic drugs to treat lung cancer. We optimize the most effective component formula of Salvia miltiorrhiza and Panax Ginseng (FMG), which is composed of Salvianolic acid A, 20(S)-Ginsenoside and Ginseng polysaccharide. We discovered that FMG selectively inhibited lung cancer cell proliferation and induced apoptosis but had no any cytotoxic effects on normal lung epithelial BEAS-2B cells. Moreover, FMG inhibited lung cancer cell migration and invasion. Mechanistically, we found that FMG significantly promoted p-PTEN expression and subsequently inhibited PI3K/AKT signaling pathway. The phosphatase activity of PTEN protein was increased after FMG bound to PTEN protein, indicating that PTEN is one of the FMG targeted proteins. In addition, FMG regulated expression of some marker proteins relevant to cell apoptosis, migration and invasion. Collectively, these results provide mechanistic insight into the anti-NSCLC of FMG by enhancing the phosphatase activity of PTEN, and suggest that FMG could be as a potential option for lung cancer treatment.

MALAT1-miR-101-SOX9 feedback loop modulates the chemo-resistance of lung cancer cell to DDP via Wnt signaling pathway

Cisplatin (DDP)-based chemotherapy is a standard strategy for lung cancer, while chemoresistance remains a major therapeutic challenge. Recent evidence highlights the crucial regulatory roles of long non-coding RNAs (lncRNA) in tumor biology. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has important roles in regulating the proliferation, invasion and migration of lung cancer cell. High MALAT1 expression in lung cancer was related to poorer clinicopathologic features in this study. MALAT1 knockdown alone was sufficient to amplify DDP-induced repression of cell viability. MALAT1 knockdown could also sensitized DDP-resistant lung cancer cells (A549/DDP and H1299/DDP) to DDP. Further assays indicated that MALAT1 acted as a competing endogenous RNA to upregulate SOX9 expression by sponging miR-101 in DDP-resistant cancer cells, through Wnt signaling pathway. Moreover, SOX9 could bind to the promoter of MALAT1 to activate its transcription. Taken together, MALAT1, miR-101 and SOX9 form a feedback loop to enhance the chemo-resistance of lung cancer cell to DDP; this MALAT1-miR-101-SOX9 feedback loop plays an important role in the chemo-resistance of lung cancer cell to DDP and may serve as a potential target for cancer treatment.

miR-155 mediates arsenic trioxide resistance by activating Nrf2 and suppressing apoptosis in lung cancer cells

Arsenic trioxide (ATO) resistance is a challenging problem in chemotherapy. However, the underlying mechanisms remain to be elucidated. In this study, we identified a high level of expression of miR-155 in a human lung adenocarcinoma A549R cell line that is highly resistant to ATO. We showed that the high level of miR-155 was associated with increased levels of cell survival, colony formation, cell migration and decreased cellular apoptosis, and this was mediated by high levels of Nrf2, NAD(P)H quinone oxidoreductase 1 (NQO1), heme oxygenase-1 (HO-1) and a high ratio of Bcl-2/Bax. Overexpression of the miR-155 mimic in A549R cells resulted in increased levels of colony formation and cell migration as well as reduced apoptosis along with increased Nrf2, NQO1 and HO-1. In contrast, silencing of miR-155 expression with its inhibitor in the cells, significantly decreased the cellular levels of Nrf2, NQO1 and HO-1 as well as the ratio of Bcl-2/Bax. This subsequently reduced the level of colony formation and cell migration facilitating ATO-induced apoptosis. Our results indicate that miR-155 mediated ATO resistance by upregulating the Nrf2 signaling pathway, but downregulating cellular apoptosis in lung cancer cells. Our study provides new insights into miR-155-mediated ATO resistance in lung cancer cells.

TRAIL, Wnt, Sonic Hedgehog, TGFβ, and miRNA Signalings Are Potential Targets for Oral Cancer Therapy

Clinical studies and cancer cell models emphasize the importance of targeting therapies for oral cancer. The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is highly expressed in cancer, and is a selective killing ligand for oral cancer. Signaling proteins in the wingless-type mouse mammary tumor virus (MMTV) integration site family (Wnt), Sonic hedgehog (SHH), and transforming growth factor β (TGFβ) pathways may regulate cell proliferation, migration, and apoptosis. Accordingly, the genes encoding these signaling proteins are potential targets for oral cancer therapy. In this review, we focus on recent advances in targeting therapies for oral cancer and discuss the gene targets within TRAIL, Wnt, SHH, and TGFβ signaling for oral cancer therapies. Oncogenic microRNAs (miRNAs) and tumor suppressor miRNAs targeting the genes encoding these signaling proteins are summarized, and the interactions between Wnt, SHH, TGFβ, and miRNAs are interpreted. With suitable combination treatments, synergistic effects are expected to improve targeting therapies for oral cancer.