Locus Summary

Gene:MIRLET7I; microRNA let-7i
Aliases: LET7I, let-7i, MIRNLET7I, hsa-let-7i
Summary:microRNAs (miRNAs) are short (20-24 nt) non-coding RNAs that are involved in post-transcriptional regulation of gene expression in multicellular organisms by affecting both the stability and translation of mRNAs. miRNAs are transcribed by RNA polymerase II as part of capped and polyadenylated primary transcripts (pri-miRNAs) that can be either protein-coding or non-coding. The primary transcript is cleaved by the Drosha ribonuclease III enzyme to produce an approximately 70-nt stem-loop precursor miRNA (pre-miRNA), which is further cleaved by the cytoplasmic Dicer ribonuclease to generate the mature miRNA and antisense miRNA star (miRNA*) products. The mature miRNA is incorporated into a RNA-induced silencing complex (RISC), which recognizes target mRNAs through imperfect base pairing with the miRNA and most commonly results in translational inhibition or destabilization of the target mRNA. The RefSeq represents the predicted microRNA stem-loop. [provided by RefSeq, Sep 2009]
Databases:miRBase, OMIM, HGNC, Ensembl, GeneCard, Gene
Source:NCBIAccessed: 10 March, 2017

Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 10 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 10 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (9)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

MicroRNA Function

Numbers shown below represent number of publications held in OncomiRDB database for Oncogenic and Tumor-Suppressive MicroRNAs.

TissueTarget Gene(s)Regulator(s)MIRLET7I Function in CancerEffect
ovary (3)
-epithelial ovarian carcinoma (1)
-ovarian cancer (1)
-epithelial ovarian cancer (1)
PGRMC1 (1)
increase paclitaxel sensitivity (1)
inhibit cell proliferation (1)
induce apoptosis (1)
decrease cell survival (1)
increase cisplatin sensitivity (1)
tumor-suppressive (2)
colorectum (1)
-colorectal cancer (1)
inhibit cell proliferation (1)
inhibit cell migration (1)
inhibit cell invasion (1)
tumor-suppressive (1)

Source: OncomiRDB Wang D. et al. Bioinformatics 2014, 30(15):2237-2238.

Latest Publications: MIRLET7I (cancer-related)

Xiao D, Barry S, Kmetz D, et al.
Melanoma cell-derived exosomes promote epithelial-mesenchymal transition in primary melanocytes through paracrine/autocrine signaling in the tumor microenvironment.
Cancer Lett. 2016; 376(2):318-27 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
The tumor microenvironment is abundant with exosomes that are secreted by the cancer cells themselves. Exosomes are nanosized, organelle-like membranous structures that are increasingly being recognized as major contributors in the progression of malignant neoplasms. A critical element in melanoma progression is its propensity to metastasize, but little is known about how melanoma cell-derived exosomes modulate the microenvironment to optimize conditions for tumor progression and metastasis. Here, we provide evidence that melanoma cell-derived exosomes promote phenotype switching in primary melanocytes through paracrine/autocrine signaling. We found that the mitogen-activated protein kinase (MAPK) signaling pathway was activated during the exosome-mediated epithelial-to-mesenchymal transition (EMT)-resembling process, which promotes metastasis. Let-7i, an miRNA modulator of EMT, was also involved in this process. We further defined two other miRNA modulators of EMT (miR-191 and let-7a) in serum exosomes for differentiating stage I melanoma patients from non-melanoma subjects. These results provide the first strong molecular evidence that melanoma cell-derived exosomes promote the EMT-resembling process in the tumor microenvironment. Thus, novel strategies targeting EMT and modulating the tumor microenvironment may emerge as important approaches for the treatment of metastatic melanoma.

Lin Z, Li JW, Wang Y, et al.
Abnormal miRNA-30e Expression is Associated with Breast Cancer Progression.
Clin Lab. 2016; 62(1-2):121-8 [PubMed] Related Publications
BACKGROUND: microRNAs (miRNAs) are involved in the regulation of various cellular processes, such as differentiation, proliferation, metabolism, and apoptosis, and they have been implicated in several diseases, including cancers.
METHODS: To assess the role of miRNA in the progression of breast cancer, we performed TaqMan-based miRNA profiling for plasma from patients with breast cancer (n = 53), unrelated diseases (n = 40), or matched healthy controls (n = 40), and for breast tumors or adjacent non-tumors (n = 41).
RESULTS: We selected 18 miRNAs with predicted roles in breast cancer and demonstrated that let-7i (p = 0.019), let-7a (p = 0.02), and miR-650 (p = 0.008) were significantly up-regulated in plasma; miR-21 (p < 0.001) is up-regulated in breast cancer tissue, and miR-30e was down-regulated in both plasma (p < 0.001) and breast cancer tissues (p = 0.004). Plasma miR-30e expression was shown to be statistically associated with age (p = 0.0402) and clinical stage (p = 0.007). However, receiver-operating characteristic curve analyses suggested that miR-30e expression cannot significantly differentiate breast cancer from healthy tissue or plasma. Consistent with a potential role for miR-30e in breast cancer, three predicted targets of miR-30e (RAB11A, BNIP3L, and RAB32) are up-regulated in breast cancer tissue.
CONCLUSIONS: These findings suggest that reduced miR-30e correlates with the clinical stage of breast cancer. It is worthwhile to further explore that the potential role of miR-30e as a tumor suppressor in breast cancer, as well as its potential therapeutic utility.

Tavano F, Copetti M, Piepoli A, et al.
Support Vector Machine Based on microRNA Expression Profiles to Predict Histological Origin of Ampullary Carcinoma: Case Report of a Patient Affected From Adenocarcinoma of the Papilla of Vater With Lynch Syndrome.
Pancreas. 2016; 45(4):626-9 [PubMed] Related Publications
Adenocarcinomas of Vater's papilla (PVAC) may originate from either the pancreatic duct or the intestinal epithelium. Conflicting data have been reported about the frequency of the 2 anatomical entities and their influence on patients' prognosis. To ascertain the anatomical origin of PVAC in a family member of a Lynch syndrome kindred, we searched for microRNA (miRNA) expression profiles on resected tumor specimens. The support vector machine was trained on our previous miRNAs expression data sets of pancreatic and colorectal tissue samples and used to classify the site of origin of the tumor in our patient. The support vector machine worked by contrasting the profiles of miRNAs in patients with pancreatic ductal and colorectal cancers to that of our patient, which was finally classified as pancreatic ductal adenocarcinoma accordingly to alterations of 55 miRNAs. The PVAC might be originated from ductal epithelium rather than from the intestinal mucosa of the papilla in the case at issue. Alteration of miR-548b-3p, miR-551a, miR-21, miR-92a, miR-let-7i, and miR-181a* emerged as potentially associated with cancer genetic susceptibility in PVAC.

Li L, Chen J, Chen X, et al.
Serum miRNAs as predictive and preventive biomarker for pre-clinical hepatocellular carcinoma.
Cancer Lett. 2016; 373(2):234-40 [PubMed] Related Publications
The extremely poor prognosis of patients with symptomatic hepatocellular carcinoma (HCC) diagnosed clinically at advanced stages suggests an urgent need for biomarkers that can be used for prospective surveillance and pre-clinical screening for early presence of pre-malignant lesions and tumors. In a retrospective longitudinal phase 3 biomarker study in seven medical centers of China, time-series and 6 months interval-serum samples were collected from chronic hepatitis B virus infected (CHB) patient cohorts at the pre-malignant or pre-clinical stages (average 6 months prior to clinical diagnosis) and CHB patients that did not develop cancer, and circulating miRNAs measured. A set of serum miRNAs including miR-193a-3p, miR-369-5p, miR-672, miR-429 and let-7i* were identified in pre-clinical HCC patients and have the potential to screen for CHB patients at high risk to develop HCC 6-12 months after miRNAs measurement. These circulating miRNAs combined with the conventional screening tools using α-fetoprotein and ultrasound, may have great promise for the prediction and prevention of HCC in high-risk populations.

Wu K, Yang Y, Zhao J, Zhao S
BAG3-mediated miRNA let-7g and let-7i inhibit proliferation and enhance apoptosis of human esophageal carcinoma cells by targeting the drug transporter ABCC10.
Cancer Lett. 2016; 371(1):125-33 [PubMed] Related Publications
Cisplatin (diamminedichloroplatinum, DDP) is widely used as the first-line treatment for patients with unresectable or no metastatic cancer. However, the appearance of DDP resistance frequently occurred in the treatment of cancers, including esophageal carcinoma (EC). The purposes of this study are to determine the antitumor effects of miR-let-7g/i (let-7g/i) on EC cells and to investigate whether let-7g and let-7i have a relationship with the drug resistance gene ABCC10 on EC cells. qRT-PCR and western blot analysis demonstrated that Bcl2-associated athanogene 3 (BAG3) and miR-let-7g/i have the opposite expression levels in primary esophageal squamous cell carcinoma tissues and EC cell lines. Overexpression of miR-let-7g/i significantly inhibited the cell proliferation and promoted DDP-induced apoptosis of EC109 and TE10 cells. Finally, ABCC10, a drug resistance gene, was identified as a functional and direct target gene of miR-let-7g/i. Luciferase reporter assay confirmed that let-7g and let-7i combined directly with 3'UTR of ABCC10, in consequence, inhibiting ABCC10 expression and enhancing cellular sensitivity to drugs. This study provides the first demonstration that miR-let-7g/i target ABCC10 and modulate DDP resistance in EC cell lines.

Ozcan O, Kara M, Yumrutas O, et al.
MTUS1 and its targeting miRNAs in colorectal carcinoma: significant associations.
Tumour Biol. 2016; 37(5):6637-45 [PubMed] Related Publications
Deregulated microRNA (miRNA) expression has been shown to be involved in the pathogenesis of several types of cancers including colorectal cancer (CRC). Thus, determining miRNA targets of genes that play critical role in the malignant transformation is very important. Here, expression levels of tumor suppressor microtubule-associated tumor suppressor 1 (MTUS1) and its regulatory miRNAs were reported. Predicted and validated targets of MTUS1 gene was determined by a computational approach. Expressions of MTUS1 and miRNAs were determined by using 96.96 Dynamic Array™ integrated fluidic circuit (Fluidigm). As a result, MTUS1 levels were found to be diminished in formalin-fixed, paraffin-embedded (FFPE) tissue samples of CRC patients compared to controls. Also, several of MTUS1 targeting miRNAs were found to be upregulated in CRC samples (miR-373-3p, 183-5p, 142-5p, 200c-3p, 19a-3p, -20a-5p, -181a-5p, -184, -181d-5p, -372-3p, 27b-3p, 98-5p, -let-7i-5p, -let-7d-5p, -let-7g-5p, -let-7b-5p, and -let-7c-5p). Of these miRNAs, miR-135b-5p, -373-3p, 183-5p, 142-5p, 200c-3p, 19a-3p showed marked expression levels. In contrast, expression levels of let-7a-5p, 7e-5p, 7f-5p, hsa-miR-125a-5p, and 125b-5p were found to be downregulated in CRC tissues. Accordingly, some of the overexpressed miRNAs especially the miR-135b-5p, -373-3p, 183-5p, 142-5p, 200c-3p, and 19a-3p may play key roles in CRC pathophysiology through MTUS1. In contrast, let-7a-5p, 7e-5p, 7f-5p, miR-125a-5p, and 125b-5p may play important roles in CRC carcinogenesis independent from the MTUS1. In conclusion, MTUS1 targeting miRNAs may play key roles in the development of CRC by downregulating tumor suppressor MTUS1.

Chen C, Hu Y, Li L
NRP1 is targeted by miR-130a and miR-130b, and is associated with multidrug resistance in epithelial ovarian cancer based on integrated gene network analysis.
Mol Med Rep. 2016; 13(1):188-96 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
Multidrug resistance (MDR) in epithelial ovarian cancer (EOC) remains a public health issue for women worldwide, and its molecular mechanisms remain to be fully elucidated. The present study aimed to predict the potential genes involved in MDR, and examine the mechanisms underlying MDR in EOC using bioinformatics techniques. In the present study, four public microarray datasets, including GSE41499, GSE33482, GSE15372 and GSE28739, available in Gene Expression Omnibus were downloaded, and 11 microRNAs (miRNA; miRs), including miR‑130a, miR‑214, let‑7i, miR‑125b, miR‑376c, miR‑199a, miR‑93, miR‑141, miR‑130b, miR‑193b* and miR‑200c, from previously published reports in PubMed were used to perform a comprehensive bioinformatics analysis through gene expression analysis, signaling pathway analysis, literature co‑occurrence and miRNA‑mRNA interaction networks. The results demonstrated that the expression of neuropilin 1 (NRP1) was upregulated, thereby acting as the most important hub gene in the integrated gene network. NRP1 was targeted by miR‑130a and miR‑130b at the binding site of chromosome 10: 33466864‑3466870, which was involved in the axon guidance signaling pathway. These results suggested that alteration of the gene expression levels of NRP1 expression may contribute to MDR in EOC. These data provide important information for further experimental investigations of the drug resistance‑associated functions of NRP1 in EOC.

Wang W, Corrigan-Cummins M, Barber EA, et al.
Aberrant Levels of miRNAs in Bone Marrow Microenvironment and Peripheral Blood of Myeloma Patients and Disease Progression.
J Mol Diagn. 2015; 17(6):669-78 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
The bone marrow (BM) microenvironment of multiple myeloma (MM) is reported to play a role in the biology of disease. In this study, we found that the extracellular BM microenvironment in MM contains a unique miRNA signature detectable by miRNA microarray and quantitative real-time PCR, which is partially represented in the peripheral blood. Eleven miRNAs were significantly decreased in both BM and serum of MM patients in comparison with controls. Evaluation of these miRNAs in plasma of a separate cohort of MM patients and controls confirmed significantly aberrant levels of let-7a, let-7b, let-7i, miR-15b, miR-16, and miR-20a in both serum and plasma. We then studied the myeloma precursor diseases and found that a subset of the MM miRNAs exhibited aberrant expression in monoclonal gammopathy of undetermined significance and smoldering myeloma. miRNA analysis of enriched CD138(+) plasma cells from MM and monoclonal gammopathy of undetermined significance found that most of the validated MM BM signature miRNAs were significantly decreased in MM plasma cells. Gene expression profiling indicated that multiple targets of the decreased miRNAs found increased expression in MM plasma cells, including ATF2, HRAS, HDAC4, TGFB1, TGFBR1, and mitogen-activated protein kinases. The findings suggest that these miRNAs are detectable in aberrant levels in the peripheral blood of patients with plasma cell proliferation and may play a role in aberrant plasma cell proliferation and disease progression.

Li M, Song Q, Song Q, et al.
Circulating miR-25-3p and miR-451a May Be Potential Biomarkers for the Diagnosis of Papillary Thyroid Carcinoma.
PLoS One. 2015; 10(7):e0132403 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
OBJECTIVE: There is no effective and reliable biomarker to distinguish benign thyroid nodules from papillary thyroid carcinomas (PTC). This study aimed at examining the levels of plasma miRNAs in patients with PTC or benign nodules to explore the potential miRNA biomarkers for PTC.
PATIENTS AND METHODS: Genome-wide plasma miRNA expression profiles were determined by the miRNA Microarray and the significantly higher levels of miRNAs were validated in plasma and tissues by quantitative RT-PCR. The levels of two miRNAs were further tested in seven patients before and after tumor excision and the potential values for the diagnosis of PTC were evaluated by receiver operating characteristic curve (ROC).
RESULTS: In comparison with that in the patients with benign nodules, eight significantly higher and three lower levels of plasma miRNAs were detected in the PTC patients. Further validation indicated that the levels of plasma miR-25-3p, miR-451a, miR-140-3p and let-7i were significantly higher in the PTC cases than in those with benign nodules or the healthy controls. Significantly higher levels of miR-25-3p and miR-451a were detected in the thyroid tissues from the PTC patients. The levels of plasma miR-25-3p and miR-451a in seven patients significantly decreased after tumor excision. ROC analyses revealed that the levels of plasma miR-25-3p at cut-off 1.41 and miR-451a at 1.38 had sensitivity of 92.8% and 88.9%, and specificity of 68.8% and 66.7% for distinguishing PTC from benign nodules, respectively.
CONCLUSION: Our findings suggest that the levels of plasma miR-25-3p and miR-451a may be valuable for the diagnosis of PTC.

Zhang GM, Long XH, Liu JM, et al.
Let-7i inhibits the malignant phenotype of osteosarcoma cells by targeting Aurora-B.
Mol Med Rep. 2015; 12(3):3543-8 [PubMed] Related Publications
Our previous study indicated that Aurora-B is involved in osteosarcoma (OS) cell invasion and metastasis; however, the mechanism underlying Aurora-B overexpression in OS remains unknown. In the present study, significantly downregulated let-7i expression in OS tissues and OS cells was observed compared with that in normal adjacent tumorous tissues and human osteoblast cell lines. Bioinformatic predictions have revealed a conserved binding site in a microRNA locus on Aurora‑B, suggesting the potential of let‑7i targeting the Aurora‑B gene. To validate this, a luciferase reporter assay was performed on OS cells. The results indicated that Aurora‑B is a likely to be a direct target negatively regulated by let‑7i. The expression of let‑7i in OS cells was restored by infection with let‑7i mimics. Results revealed that Aurora‑B mRNA and protein expression levels were significantly decreased. Furthermore, the proliferation, migration and invasion abilities of OS cells were significantly suppressed by infection with let‑7i mimics. Notably, the inhibitory effect of silencing Aurora‑B by LV‑shAurora‑B on cell proliferation, migratory and invasive ability was significantly lower than that by let‑7i mimics, which indicated that let‑7i inhibits cell malignant phenotypes partially by targeting Aurora‑B in OS cells. All data suggested that let‑7i may be a novel potential target for OS treatment.

Yan W, Liu Y, Yang P, et al.
MicroRNA profiling of Chinese primary glioblastoma reveals a temozolomide-chemoresistant subtype.
Oncotarget. 2015; 6(13):11676-82 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
Accumulating evidence demonstrates that defining molecular subtypes based on objective genetic alterations may permit a more rational, patient-specific approach to molecular targeted therapy across various cancers. The objective of this study was to subtype primary glioblastoma (pGBM) based on MicroRNA (miRNA) profiling in Chinese population. Here, miRNA expression profiles from 82 pGBM samples were analyzed and 78 independent pGBM samples were used for qRT-PCR validation. We found that two distinct subgroups with different prognosis and chemosensitivities to temozolomide (TMZ) in Chinese pGBM samples. One subtype is TMZ chemoresistant (termed the TCR subtype) and confers a poor prognosis. The other subtype is TMZ-chemosensitive (termed the TCS subtype) and confers a relatively better prognosis compared with the TCR subtype. A classifier consisting of seven miRNAs was then identified (miR-1280, miR-1238, miR-938 and miR-423-5p (overexpressed in the TCR subtype); and let-7i, miR-151-3p and miR-93 (downregulated in the TCR subtype)), which could be used to assign pGBM samples to the corresponding subtype. The classifier was validated using both internal and external samples. Meanwhile, the genetic alterations of the TCR and TCS subtypes were also analyzed. The TCR subtype was characterized by no IDH1 mutation, and EGFR and Ki-67 overexpression. The TCS subtype displayed the opposite situation. Taken together, the results indicate a distinct subgroup with poor prognosis and TMZ-chemoresistance.

Li FQ, Xu B, Wu YJ, et al.
Differential microRNA expression in signet-ring cell carcinoma compared with tubular adenocarcinoma of human gastric cancer.
Genet Mol Res. 2015; 14(1):739-47 [PubMed] Related Publications
Gastric cancer is a disease with a heterogeneous pathology; its pathological mechanisms remain unclear because there is a poor understanding of its etiology. In this study, we identified differentially expressed microRNAs (miRNAs) among various gastric cancer subtypes. miRNA microarray analysis and bioinformatic analysis were used to compare miRNA expression between the signet-ring cell carcinoma and tubular adenocarcinoma subtypes of gastric cancer. Thirteen dysregulated miRNAs were identified in signet-ring cell carcinoma compared with tubular adenocarcinoma: miR-30a, miR-26b, miR-381, let-7i, miR-29c, miR-543, miR-499-3p, miR-628-3p, miR-524-5p, miR-181b, miR-1914, miR-663b, and miR-676. This is the first time that miR-499-3p, miR-628-3p, miR-524-5p, and miR-1914 have been identified in gastric cancer tissues. Bioinformatic analysis using target prediction algorithms indicated that these miRNAs are directly involved in gastric cancer pathogenesis and have different pathological mechanisms in various subtypes of signet-ring cell carcinoma and tubular adenocarcinoma. The miRNA expression patterns in different gastric adenocarcinoma subtypes may help discriminate between signet-ring cell and tubular gland cancer or other gastric cancer subtypes that would otherwise be difficult to identify using routine histological and immunohistochemical analyses. These preliminary data should be verified in further prospective studies.

Hur K, Toiyama Y, Schetter AJ, et al.
Identification of a metastasis-specific MicroRNA signature in human colorectal cancer.
J Natl Cancer Inst. 2015; 107(3) [PubMed] Article available free on PMC after 01/07/2017 Related Publications
BACKGROUND: Distant metastasis is the major cause of mortality in colorectal cancer (CRC). We performed a systemic, comprehensive discovery for expression patterns of metastasis-specific microRNAs (miRNAs) by directly comparing primary CRCs (pCRCs) and matched liver metastases (LMs) and evaluated the feasibility of their clinical application as metastasis-specific biomarkers.
METHODS: CRC metastasis-specific miRNA profiles were generated by analyzing nine pairs of pCRC and LM tissues, followed by quantitative validation in an independent cohort of 58 pairs of matched pCRC and LM tissues. We evaluated associations between miRNA expression and patient survival and ability to predict metastasis in another 84 patients with CRC. Subsequently, associations were quantitatively validated in 175 CRC tissues and 169 serum samples. Kaplan-Meier, Cox regression, and logistic regression analyses were used. All statistical tests were two-sided.
RESULTS: Twenty-three miRNAs were identified that were differentially expressed between pCRC and LM (P < .001; FDR < .5). Four miRNAs downregulated in LM (let-7i, miR-10b, miR-221, and miR-320a) and one upregulated miR (miR-885-5p) were quantitatively validated in pCRC (P < .0001). Low let-7i expression in pCRC tissue predicted worsened prognosis (hazard ratio [HR] = 5.0, 95% confidence interval [CI] = 1.0 to 24.4, P = .0479) as well as distant metastasis (odds ratio [OR] = 5.5, 95% CI = 1.1 to 26.8, P = .0334). High miR-10b expression in pCRC tissue independently predicted distant metastasis (OR = 4.9, 95% CI = 1.2 to 19.7, P = .0248). High serum miR-885-5p expression independently predicted prognosis (HR = 2.9, 95% CI = 1.1 to 7.5, P = .0323), LN metastasis (OR = 3.0, 95% CI = 1.3 to 7.2, P = .0116), and distant metastasis (OR = 3.1, 95% CI = 1.0 to 10.0, P = .0456), whereas tissue miR-885-5p expression did not. Expression patterns of miRNAs were confirmed by in situ hybridization.
CONCLUSIONS: We discovered a metastasis-specific miRNA signature in pCRCs and discovered novel tissue- and serum-based CRC metastasis-specific miRNA biomarkers through intensive validation. These unique miRNAs may be clinically applicable to predict prognosis and distant metastasis in CRC.

Tian Y, Hao S, Ye M, et al.
MicroRNAs let-7b/i suppress human glioma cell invasion and migration by targeting IKBKE directly.
Biochem Biophys Res Commun. 2015; 458(2):307-12 [PubMed] Related Publications
We demonstrated that IKBKE is overexpressed in human gliomas and that the downregulation of IKBKE markedly inhibits the proliferative and invasive abilities of glioma cells, which is consistent with the results reported by several different research groups. Therefore, IKBKE represents a promising therapeutic target for the treatment of glioma. In the present study, we verified that the microRNAs let-7b and let-7i target IKBKE through luciferase assays and found that let-7b/i mimics can knock down IKBKE and upregulate E-cadherin through western blot analysis. Moreover, the expression levels of let-7b/i were significantly lower in glioma cell lines than that in normal brain tissues, as determined by quantitative real-time PCR. Furthermore, let-7b/i inhibit the invasion and migration of glioma cells, as determined through wound healing and Transwell assays. The above-mentioned data suggest that let-7b/i inhibit the invasive ability of glioma cells by directly downregulating IKBKE and indirectly upregulating E-cadherin.

Su Z, Hou XK, Wen QP
Propofol induces apoptosis of epithelial ovarian cancer cells by upregulation of microRNA let-7i expression.
Eur J Gynaecol Oncol. 2014; 35(6):688-91 [PubMed] Related Publications
OBJECTIVE: Propofol is one of the extensively and commonly used intravenous anaesthetic agents. The aims of the current study were to evaluate effects of propofol on the behavior of human epithelial ovarian cancer (EOC) cells and role of miR-let-7i in these effects.
MATERIALS AND METHODS: The effects of propofol on cell proliferation and apoptosis were detected by MTT assays and flow cytometry. Real-time polymerase chain reaction (PCR) was used to assess miR-let-7i expression in human EOC cells OVCAR-3 with or without propofol treatment. Finally, the authors evaluated the effect ofmiR-let-7i on propofol-induced anti-tumor activity using anti-miR-let-7i.
RESULTS: Propofol inhibited the proliferation of OVCAR-3 cells in a dose- and time-dependent manner. After exposure to propofol for 24 hours, OVCAR-3 cells showed increased apoptosis and increased expression of miR-let-7i. Finally, anti-miR-let-7i reversed the effect of propofol on cell proliferation and apoptosis.
CONCLUSIONS: Propofol can effectively inhibit proliferation and induce apoptosis of EOC cells and modulation of miR-let-7i possibly contributes to the anti-tumor action of propofol.

Liu WJ, Xu Q, Sun LP, et al.
Expression of serum let-7c, let-7i, and let-7f microRNA with its target gene, pepsinogen C, in gastric cancer and precancerous disease.
Tumour Biol. 2015; 36(5):3337-43 [PubMed] Related Publications
This study examined the expression patterns of serum let-7 microRNA (miRNA) and its target gene, pepsinogen C (PGC), in gastric cancer (GC) and precancerous disease patients to evaluate their diagnostic efficiency for GC and its precursor and to investigate any correlation between the two. Serum samples were taken from 638 patients, including 214 GC patients, 222 atrophic gastritis (AG) patients, and 202 controls (CON). The expression of serum let-7 miRNA was detected in control-AG (precancerous disease) through to GC patients using quantitative reverse-transcription polymerase chain reaction. Serum PGC was determined by enzyme-linked immuno-sorbent assay. PGC expression in situ was detected by immunohistochemistry staining. The luciferase reporter gene system was used to verify correlation between let-7 miRNA and its predicted target gene. The results showed that serum let-7c, let-7i, and let-7f demonstrated significant differences in the CON-AG-GC sequence (P = 0.017, P < 0.001, P = 0.003, respectively); let-7c was significantly lower in the AG group, and let-7i and let-7f were significantly higher in the GC group. Significantly different expressions of serum PGC were found among the three diseases, and also between AG vs. CON, and GC vs. CON (P = 0.027, P = 0.001, respectively). Linear-regression analysis suggested that serum let-7c was negatively correlated to the expression of PGC (r = -0.096, P = 0.047), and serum let-7c, let-7i, and let-7f showed no association with PGC expression in tissue. In addition, serum let-7c, let-7f, and let-7i showed significant correlations with environment factors. Serum let-7c, let-7i, and let-7f demonstrated significant differences in the CON-AG-GC disease sequence indicating that let-7 miRNA might have value by serving as potential biomarker in the diagnosis of GC or its precancerous diseases. There were significant negative correlations between serum let-7c and its target gene PGC expression.

Ralfkiaer U, Lindahl LM, Lindal L, et al.
MicroRNA expression in early mycosis fungoides is distinctly different from atopic dermatitis and advanced cutaneous T-cell lymphoma.
Anticancer Res. 2014; 34(12):7207-17 [PubMed] Related Publications
Mycosis fungoides (MF) is the most common variant of cutaneous T-cell lymphoma (CTCL). MF is characterized by chronic inflammation dominated by cluster of differentiation 4-positive (CD4(+)) T-cells and T helper 2 cytokines, and as the malignant T-cell clone is initially elusive, early diagnosis is often impossible. MF usually takes an indolent course, but for unknown reasons may turn into an aggressive disease with a poor prognosis. Herein, we used a global quantitative real-time polymerase chain reaction platform to study microRNA (miR) expression in patients with early MF (n=13), more advanced CTCL (n=42), and atopic dermatitis (AD, n=20). Thirty-eight miRs were differentially expressed (≥2-fold) in early MF vs. AD and 36 in early MF vs. more advanced disease. miRs that distinguish early MF from AD included both up-regulated (miR-155, miR-146a, 146b-5p, miR-342-3p, let-7i*) and down-regulated (miR-203, miR-205) miRs previously implicated in advanced CTCL. When comparing early MF to more advanced CTCL, additional miRs were significantly up-regulated including miRs which are part of the oncogenic miR-17/92, 106b/25 and 106a/363 clusters. In 16 patients for whom detailed follow-up data were available, 72 miRs were found differentially expressed between patients with progressive vs. those with non-progressive disease, again including miRs with a known relevance for lymphomagenesis, e.g. miR-155, miR-21, let-7i, miR-16, miR-142-3p, miR-146b-5p, miR-92a, miR-93 and miR-106a. In conclusion, we showed that early MF and AD display very different miR profiles despite their clinical, histological, and immunological similarities. During progression, an additional set of miRs becomes deregulated, suggesting their role in disease progression. These data suggest that miR profiling in CTCL may be a key to improving both diagnosis and risk prediction.

Langhe R, Norris L, Saadeh FA, et al.
A novel serum microRNA panel to discriminate benign from malignant ovarian disease.
Cancer Lett. 2015; 356(2 Pt B):628-36 [PubMed] Related Publications
Ovarian cancer is the seventh most common cancer in women and the most frequent cause of gynaecological malignancy-related mortality in women. Currently, no standardized reliable screening test exists. MicroRNA profiling has allowed the identification of signatures associated with diagnosis, prognosis and response to treatment of human tumours. The aim of this study was to determine if a microRNA signature could distinguish between malignant and benign ovarian disease. A training set of 5 serous ovarian carcinomas and 5 benign serous cystadenomas were selected for the initial experiments. The validation set included 20 serous ovarian carcinomas and 20 benign serous cystadenomas. The serum/plasma focus microRNA Exiqon panel was used for the training set. For the validation set a pick and mix Exiqon panel, which focuses on microRNAs of interest was used. A panel of 4 microRNAs (let-7i-5p, miR-122, miR-152-5p and miR-25-3p) was significantly down regulated in cancer patients. These microRNAs target WNT signalling, AKT/mTOR and TLR-4/MyD88, which have previously been found to play a role in ovarian carcinogenesis and chemoresistance. let-7i-5p, miR-122, miR-152-5p and miR-25-3p could act as diagnostic biomarkers in ovarian cancer.

Huang J, Wu J, Li Y, et al.
Deregulation of serum microRNA expression is associated with cigarette smoking and lung cancer.
Biomed Res Int. 2014; 2014:364316 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
Lung cancer is the leading cause of cancer-related death and cigarette smoking is the main risk factor for lung cancer. Circulating microRNAs (miRNAs) are considered potential biomarkers of various cancers, including lung cancer. However, it is unclear whether changes in circulating miRNAs are associated with smoking and smoking-related lung cancer. In this study, we determined the serum miRNA profiles of 10 nonsmokers, 10 smokers, and 10 lung-cancer patients with miRCURY LNA microRNA arrays. The differentially expressed miRNAs were then confirmed in a larger sample. We found that let-7i-3p and miR-154-5p were significantly downregulated in the sera of smokers and lung-cancer patients, so the serum levels of let-7i-3p and miR-154-5p are associated with smoking and smoking-related lung cancer. The areas under receiver operating characteristic curves for let-7i-3p and miR-154-5p were approximately 0.892 and 0.957, respectively. In conclusion, our results indicate that changes in serum miRNAs are associated with cigarette smoking and lung cancer and that let-7i-3p and miR-154-5p are potential biomarkers of smoking-related lung cancer.

Ding CF, Chen WQ, Zhu YT, et al.
Circulating microRNAs in patients with polycystic ovary syndrome.
Hum Fertil (Camb). 2015; 18(1):22-9 [PubMed] Related Publications
AIM: To explore the pattern of expression of circulating miRNAs in patients with polycystic ovary syndrome (PCOS).
MATERIALS AND METHODS: Microarray and qRT-PCR were used to investigate circulating miRNAs in PCOS during clinical diagnosis. The targets of dys-regulated miRNAs were predicted using bioinformatics, followed by function and pathway analysis using the databases of Gene Ontology and the KEGG pathway.
RESULTS: BMI, triglyceride, HOMA-IR, Testosterone and CRP levels were significantly higher, while estradiol was significantly lower in PCOS than in control groups. After SAM analysis, 5 circulating miRNAs were significantly up-regulated (let-7i-3pm, miR-5706, miR-4463, miR-3665, miR-638) and 4 (miR-124-3p, miR-128, miR-29a-3p, let-7c) were down-regulated in PCOS patients. Hierarchical clustering showed a general distinction between PCOS and control samples in a heat map. After joint prediction by different statistical methods, 34 and 41 genes targeted were up-and down-regulated miRNAs, in PCOS and controls, respectively. Further, GO and KEGG analyses revealed the involvement of the immune system, ATP binding, MAPK signaling, apoptosis, angiogenesis, response to reactive oxygen species and p53 signaling pathways in PCOS.
CONCLUSIONS: We report a novel non-invasive miRNA profile which distinguishes PCOS patients from healthy controls. The miRNA-target database may provide a novel understanding of PCOS and potential therapeutic targets.

Zhan C, Yan L, Wang L, et al.
Identification of reference miRNAs in human tumors by TCGA miRNA-seq data.
Biochem Biophys Res Commun. 2014; 453(3):375-8 [PubMed] Related Publications
Although the accuracy of detecting the expression of miRNAs by quantitative real-time polymerase chain reaction (qRT-PCR) is highly dependent on reliable reference miRNAs, many commonly used reference miRNAs are not stably expressed and as such are not suitable for quantification and normalization of qRT-PCR data. To solve this problem, we analyzed the global expression profiles of thousands of samples in 14 types of common human tumors released by The Cancer Genome Atlas (TCGA), and identified the most stably and highly expressed miRNAs as candidate reference miRNAs in each type of tumor. We found that miR-361-5p and let-7i-5p were the most recommended candidate reference miRNAs in nine and eight types of tumors, respectively, followed by let-7a-5p, mir-28-5p and miR-99b-5p. Our results are of important value to those researchers focused on miRNA; however, these candidate reference miRNAs still need to be validated prior to their use in qRT-PCR studies.

Babapoor S, Fleming E, Wu R, Dadras SS
A novel miR-451a isomiR, associated with amelanotypic phenotype, acts as a tumor suppressor in melanoma by retarding cell migration and invasion.
PLoS One. 2014; 9(9):e107502 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
miRNAs are key regulatory small non-coding RNAs involved in critical steps of melanoma tumorigenesis; however, the relationship between sequence specific variations at the 5' or 3' termini (isomiR) of a miRNA and cancer phenotype remains unclear. Deep-sequencing and qRT-PCR showed reduced expression of miR-144/451a cluster and most abundant isomiR (miR451a.1) in dysplastic nevi, in-situ and invasive melanomas compared to common nevi and normal skin (n = 101). miRNA in situ hybridization reproducibly confirmed lost miR-451a.1 in melanoma compared to nevus cells or adjacent keratinocytes. Significantly higher expression of miR-451a.1 was associated with amelanotic phenotype in melanomas (n = 47). In contrast, miR-451a was associated with melanotic phenotype, absent pagetoid scatter of intraepidermal melanocytes, superficial spreading histological subtype and tumor inflammation. Sequencing miRNAs from cultured melanocytes with cytoplasmic melanin gradient (light, medium to dark) showed absent miR-451a while revealing other melanin-associated miRNAs, e.g. miR-30b, miR-100 and miR-590 in darkly and let-7a, let-7i and let-7f in lightly to moderately pigmented cultured melanocytes. Ectopic expression of miR-144/451a in melanoma cell lines resulted in markedly higher levels of mature miR-451a.1 than miR451a or miR-144; and significantly retarded cell migration and inhibited invasion in a glucose-sensitive manner. Surprisingly, these effects were not mediated by calcium binding protein 39 (CAB39), a proven miR451a gene target. miR-144/miR-451a cluster is a novel miRNA locus with tumor suppressive activity in melanoma.

Pak JH, Kim IK, Kim SM, et al.
Induction of cancer-related microRNA expression profiling using excretory-secretory products of Clonorchis sinensis.
Parasitol Res. 2014; 113(12):4447-55 [PubMed] Related Publications
Clonorchis sinensis is a carcinogenic human liver fluke by which chronic infection is strongly associated with the development of cholangiocarcinoma. Although this cholangiocarcinoma is caused by both physical and chemical irritation from direct contact with adult worms and their excretory-secretory products (ESPs), the precise molecular events of the host-pathogen interactions remain to be elucidated. To better understand the effect of C. sinensis infection on cholangiocarcinogenesis, we profiled the kinetics of changes in cancer-related microRNAs (miRNAs) in human cholangiocarcinoma cells (HuCCT1) treated with C. sinensis ESPs for different periods. Using miRNA microarray chips containing 135 cancer-related miRNAs, we identified 16 miRNAs showing differentially altered expression following ESP exposure. Of these miRNAs, 13 were upregulated and 3 were downregulated in a time-dependent manner compared with untreated controls. Functional clustering of these dysregulated miRNAs revealed involvement in cell proliferation, inflammation, oncogene activation/suppression, migration/invasion/metastasis, and DNA methylation. In particular, decreased expression of let-7i, a tumor suppressor miRNA, was found to be associated with the ESP-induced upregulation of TLR4 mRNA and protein, which contribute to host immune responses against liver fluke infection. Further real-time quantitative PCR analysis using ESP-treated normal cholangiocytes (H69) revealed that the expressions of nine miRNAs (miR-16-2, miR-93, miR-95, miR-153, miR-195, miR-199-3P, let7a, let7i, and miR-124a) were similarly regulated, indicating that the cell proliferation and inhibition of tumor suppression mediated by these miRNAs is common to both cancerous and non-cancerous cells. These findings constitute further our understanding of the multiple cholangiocarcinogenic pathways triggered by liver fluke infection.

Weng L, Ziliak D, Lacroix B, et al.
Integrative "omic" analysis for tamoxifen sensitivity through cell based models.
PLoS One. 2014; 9(4):e93420 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
It has long been observed that tamoxifen sensitivity varies among breast cancer patients. Further, ethnic differences of tamoxifen therapy between Caucasian and African American have also been reported. Since most studies have been focused on Caucasian people, we sought to comprehensively evaluate genetic variants related to tamoxifen therapy in African-derived samples. An integrative "omic" approach developed by our group was used to investigate relationships among endoxifen (an active metabolite of tamoxifen) sensitivity, SNP genotype, mRNA and microRNA expressions in 58 HapMap YRI lymphoblastoid cell lines. We identified 50 SNPs that associate with cellular sensitivity to endoxifen through their effects on 34 genes and 30 microRNA expression. Some of these findings are shared in both Caucasian and African samples, while others are unique in the African samples. Among gene/microRNA that were identified in both ethnic groups, the expression of TRAF1 is also correlated with tamoxifen sensitivity in a collection of 44 breast cancer cell lines. Further, knock-down TRAF1 and over-expression of hsa-let-7i confirmed the roles of hsa-let-7i and TRAF1 in increasing tamoxifen sensitivity in the ZR-75-1 breast cancer cell line. Our integrative omic analysis facilitated the discovery of pharmacogenomic biomarkers that potentially affect tamoxifen sensitivity.

Subramanian M, Francis P, Bilke S, et al.
A mutant p53/let-7i-axis-regulated gene network drives cell migration, invasion and metastasis.
Oncogene. 2015; 34(9):1094-104 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
Most p53 mutations in human cancers are missense mutations resulting in a full-length mutant p53 protein. Besides losing tumor suppressor activity, some hotspot p53 mutants gain oncogenic functions. This effect is mediated in part, through gene expression changes due to inhibition of p63 and p73 by mutant p53 at their target gene promoters. Here, we report that the tumor suppressor microRNA let-7i is downregulated by mutant p53 in multiple cell lines expressing endogenous mutant p53. In breast cancer patients, significantly decreased let-7i levels were associated with missense mutations in p53. Chromatin immunoprecipitation and promoter luciferase assays established let-7i as a transcriptional target of mutant p53 through p63. Introduction of let-7i to mutant p53 cells significantly inhibited migration, invasion and metastasis by repressing a network of oncogenes including E2F5, LIN28B, MYC and NRAS. Our findings demonstrate that repression of let-7i expression by mutant p53 has a key role in enhancing migration, invasion and metastasis.

Xie J, Chen M, Zhou J, et al.
miR-7 inhibits the invasion and metastasis of gastric cancer cells by suppressing epidermal growth factor receptor expression.
Oncol Rep. 2014; 31(4):1715-22 [PubMed] Related Publications
The present study profiled differentially expressed microRNAs (miRs) in gastric cancer cell lines and then investigated miR-7 expression in gastric cancer tissue specimens and the effects of miR-7 on the growth, invasion and metastasis of gastric cancer cells and the underlying molecular events. A microRNA microarray was used to profile differentially expressed miRNAs in human gastric cancer cell lines relative to a normal stomach mucosal epithelial cell line. The miRNA miR-7 was selected for further investigation, which included real-time reverse-transcription PCR (qRT-PCR) analysis of miR-7 levels in different gastric cancer cell lines and tissues and distant non-tumor tissues from patient resections. Cell counting kit-8 (CCK-8), Transwell migration and invasion, and western blot assays were performed to assess tumor cell viability, invasion and gene expression, respectively, after miR-7 transfection. The miRNA microarray profiling revealed 14 upregulated miRNAs (including miR-21, miR-26b and miR-30b) and 19 downregulated miRNAs (including let-7i, miR-7 and miR-622) between gastric cancer and normal cell lines. The qRT-PCR analysis confirmed that reduced miR-7 expression occurred more frequently in poorly and moderately differentiated gastric cancer MGC-803, MKN-45 and SGC-7901 cell lines than in the well-differentiated gastric cancer NCI-N87 cell line, which was consistent with the results for gastric cancer tissues. Expression of miR-7 was downregulated in 86.9% (20/23) of the gastric cancer tissues compared with that in the distant non-tumor tissues. Restoration of miR-7 expression significantly inhibited tumor cell viability, invasiveness and migration when compared with the control cells. Luciferase assay confirmed the epidermal growth factor receptor (EGFR) as a target gene of mR-7, and expression of miR-7 significantly suppressed EGFR expression at both the mRNA and protein levels. The data from the present study demonstrated that reduced miR-7 expression contributes to gastric cancer development and progression. Further study will investigate miR-7 in the regulation of EGFR expression in vitro and in vivo.

Gadducci A, Sergiampietri C, Lanfredini N, Guiggi I
Micro-RNAs and ovarian cancer: the state of art and perspectives of clinical research.
Gynecol Endocrinol. 2014; 30(4):266-71 [PubMed] Related Publications
Dysregulation of microRNA (mi-RNA) expression plays a major role in the development and progression of most human malignancies. Members of the miR-200 family, miR-182, miR-214 and miR-221 are frequently up-regulated, whereas miR-100, let-7i, miR-199a, miR-125b, mir-145 and miR-335 are often down-regulated in ovarian cancer compared with normal ovarian tissue. Most mi-RNA signatures are overlapping in different tumor histotypes but some mi-RNAs seem to be histotype specific. For instance, the endometrioid type shares with the serous and clear cell types the up-regulation of miR-200 family members, but also presents over-expression of miR-21, miR-202 and miR-205. Clear cell carcinoma has a significantly higher expression of miR-30a and miR-30a*, whereas mucinous histotype has elevated levels of miR-192/194. In vitro and in vivo investigations have shown that several mi-RNAs can modulate the sensitivity of ovarian cancer to platinum and taxane, and clinical studies have suggested that mi-RNA profiling may predict the outcome of patients with this malignancy. Some mi-RNAs could be used as biomarkers to identify patients that might benefit from the addition of molecularly targeted agents (i.e. anti-angiogenic agents, MET inhibitors and poly(ADP-ribose) polymerase (PARP) inhibitors) to standard chemotherapy. Moreover, mi-RNAs could represent potential targets for the development of novel therapies.

Gowrishankar B, Ibragimova I, Zhou Y, et al.
MicroRNA expression signatures of stage, grade, and progression in clear cell RCC.
Cancer Biol Ther. 2014; 15(3):329-41 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
Clear cell RCC is the most common, and more likely to metastasize, of the three main histological types of RCC. Pathologic stage is the most important prognostic indicator and nuclear grade can predict outcome within stages of localized RCC. Epithelial tumors are thought to accumulate a series of genetic and epigenetic changes as they progress through well-defined clinical and histopathological changes. MicroRNAs (miRNAs) are involved in the regulation of mRNA expression from many human genes and miRNA expression is dysregulated in cancer. To better understand the contribution of dysregulated miRNA expression to the progression and biology of ccRCC, we examined the differences in expression levels of 723 human miRNAs through a series of analyses by stage, grade, and disease progression status in a large series of 94 ccRCC. We found a consistent signature that included significant upregulation of miR-21-5p, 142-3p, let-7g-5p, let-7i-5p and 424-5p, as well as downregulation of miR-204-5p, to be associated with ccRCC of high stage, or high grade, or progression. Discrete signatures associated with each of stage, grade, or progression were also identified. The let-7 family was significantly downregulated in ccRCC compared with normal renal parenchyma. Expression of the 6 most significantly differentially expressed miRNAs between ccRCC was verified by stem-loop qRT-PCR. Pathways predicted as targets of the most significantly dysregulated miRNAs included signaling, epithelial cancers, metabolism, and epithelial to mesenchymal transition. Our studies help to further elucidate the biology underlying the progression of ccRCC and identify miRNAs for potential translational application.

Li WB, Chen HY, Zhang W, et al.
Relationship between magnetic resonance imaging features and miRNA gene expression in patients with glioblastoma multiforme.
Chin Med J (Engl). 2013; 126(15):2881-5 [PubMed] Related Publications
BACKGROUND: Magnetic resonance imaging (MRI) is commonly utilized as part of the diagnostic workup for the clinical diagnosis of glioblastoma multiforme (GBM), further guiding the clinical treatment of this aggressive cancer. Recent research has shown that microRNAs (miRNAs) may act as oncogenes, or in some cases, tumor suppressor genes that in turn may reflect the genotypic features of GBM. This study aimed to investigate the relationship between MRI features and miRNA gene expression in patients with glioblastoma multiforme.
METHODS: In order to identify the relationship between the radiographic findings of MRI and those identified changes in miRNA gene expression of GBM, we reviewed the MRI images of GBM patients and compared them with the identified miRNA expression profiles utilizing microarray analysis of paired GBM tumor samples. We chose five MRI imaging features: (1) contrast tumor enhanced/necrosis ratio, (2) contrast tumor enhanced/T2 ratio, (3) multiple lesions, (4) hemorrhage, and (5) necrotic volume. The relationship between these five imaging features and miRNA expression was studied using significance analysis of microarrays analysis.
RESULTS: We found that the expression of miRNAs such as hsa-miR-892b, hsa-miR-892a, and hsa-miR-888 was inversely correlated with an enhanced/necrosis ratio ≥ 1. The miRNAs such as hsa-miR-95, hsa-miR-498, and hsa-miR-1300 were associated with a contrast tumor enhanced/T2 ratio ≥1. The miRNAs such as hsa-miR-612, hsa-miR-524-3, and hsamiR-1282 were associated with multiple lesions identified on MRI and the expression of miR-221 was associated with hemorrhage by GBM. The expression of miR-let-7, including miR-let-7f, miR-let-7i, and miR-let-7f-1*, was downregulated in the hemorrhage group. The gene expression of miRNAs such as hsa-miR-140-5p, hsa-miR-30e, and hsa-miR-301a was relatively low when compared with the larger necrotic volume group as identified by MRI.
CONCLUSIONS: The miRNA gene expression profiles correlate with several selected MRI features of patients with GBM. Further analysis of key imaging features of MRI with correlation with miRNA gene expression patterns may help to guide treatment decisions based on these unique correlative profiles of GBM.

Yang Y, Li H, Hou S, et al.
The noncoding RNA expression profile and the effect of lncRNA AK126698 on cisplatin resistance in non-small-cell lung cancer cell.
PLoS One. 2013; 8(5):e65309 [PubMed] Article available free on PMC after 01/07/2017 Related Publications
BACKGROUND: The efficacy of cisplatin-based chemotherapy in non-small-cell lung cancer is limited by the acquired drug resistance. Identification the RNAs related to the cisplatin resistance may help to improve clinical response rates.
METHODS: Microarray expression profiling of mRNAs, lncRNA and miRNA was undertaken in A549 cells and cisplatin resistant A549/CDDP cells. Differentially expressed mRNAs, lncRNAs and miRNAs, verified by realtime RT-PCR, were subjected to pathway analysis. Expression of NKD2 and β-catenin was assessed by realtime RT-PCR and western blot analysis. The effect of lncRNA AK126698 on cisplatin induced apoptosis was investigated by annexin-V/PI flow cytometry.
RESULTS: In total, 1471 mRNAs, 1380 lncRNAs and 25 miRNAs differentially expressed in A549/CDDP and A549 cells. Among them, 8 mRNAs, 8 lncRNAs and 5 miRNAs differentially expressed in gene chip analysis were validated. High-enrichment pathway analysis identified that some classical pathways participated in proliferation, differentiation, avoidance of apoptosis, and drug metabolism were differently expressed in these cells lines. Gene co-expression network identified many genes like FN1, CTSB, EGFR, and NKD2; lncRNAs including BX648420, ENST00000366408, and AK126698; and miRNAs such as miR-26a and let-7i potentially played a key role in cisplatin resistance. Among which, the canonical Wnt pathway was investigated because it was demonstrated to be targeted by both lncRNAs and miRNAs including lncRNA AK126698. Knockdown lncRNA AK126698 not only greatly decreased NKD2 which can negatively regulate Wnt/β-catenin signaling but also increased the accumulation and nuclear translocation of β-catenin, and significantly depressed apoptosis rate induced by cisplatin in A549 cells.
CONCLUSION: Cisplatin resistance in non-small-cell lung cancer cells may relate to the changes in noncoding RNAs. Among these, AK126698 appears to confer cisplatin resistance by targeting the Wnt pathway.

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