Identification of aberrantly expressed miRNAs in rectal cancer

Disturbance of miRNA expression may play a key role in the initiation and progression of colorectal cancer (CRC). CRC should be viewed as a heterogeneous disease, but previous studies have only screened dysregulated miRNAs in CRC from a panel of 96, 145, 287 and 455 miRNAs, respectively. It is necessary to identify new aberrantly expressed miRNAs in rectal cancer. In this study tissue samples were derived from patients undergoing a surgical procedure to remove a portion of cancers. The expression profile of 904 miRNAs was analyzed using a miRCURY? LNA Array from 6-paired rectal cancers and normal tissues. The expression levels of 4 miRNAs were compared by real-time PCR between colon and rectal cancer, and also the expression levels of metastatic miRNAs in different stages of rectal cancer were analyzed. We found that 67 miRNA precursors are upregulated in rectal cancer (p<0.05) and 21 of those have never been reported in colorectal cancer (CRC); 39 miRNA precursors are downregulated (p<0.05) and 24 novel dysregulated miRNAs were identified in rectal cancer. miR-31, miR-126 and miR-143 are differentially expressed between colon cancer and rectal cancer. Here, we report an miRNA profile of rectal cancer, and we identified differential expression patterns of miRNAs between rectal and colon cancers. This novel information may suggest the potential roles of these miRNAs in the diagnosis of rectal cancer.     

microRNA Expression Profile in Patients with Stage II Colorectal Cancer: A Turkish Referral Center Study

Background: There are increasing data about microRNAs (miRNA) in the literature, providing abundantevidence that they play important roles in pathogenesis and development of colorectal cancer. In this study, weaimed to investigate the miRNA expression profiles in surgically resected specimens of patients with recurrentand non-recurrent colorectal cancer. Materials and Methods: The study population included 40 patients withstage II colorectal cancer (20 patients with recurrent tumors, and 20 sex and age matched patients withoutrecurrence), who underwent curative colectomy between 2004 and 2011 without adjuvant therapy. Expression of16 miRNAs (miRNA-9, 21, 30d, 31, 106a, 127, 133a, 133b, 135b, 143, 145, 155, 182, 200a, 200c, 362) was verifiedby quantitative real-time polymerase chain reaction (qRT-PCR) in all resected colon cancer tissue samples andin corresponding normal colonic tissues. Data analyses were carried out using SPSS 15 software. Values werestatistically significantly changed in 40 cancer tissues when compared to the corresponding 40 normal colonictissues (p<0.001). MiR-30d, miR-133a, miR-143, miR-145 and miR-362 expression was statistically significantlydownregulated in 40 resected colorectal cancer tissue samples (p<0.001). When we compared subgroups,miRNA expression profiles of 20 recurrent cancer tissues were similar to all 40 cancer tissues. However in 20non-recurrent cancer tissues, miR-133a expression was not significantly downregulated, moreover miR-133bexpression was significantly upregulated (p<0.05). Conclusions: Our study revealed dysregulation of expressionof ten miRNAs in Turkish colon cancer patients. These miRNAs may be used as potential biomarkers for earlydetection, screening and surveillance of colorectal cancer, with functional effects on tumor cell behavior.     

Circulatory miR-628-5p is downregulated in prostate cancer patients

Prostate cancer (PCa) is a major health concern for men in the USA. Aberrant expression of microRNAs (miRNAs) has been associated with the pathogenesis of various cancers, including PCa. Circulatory forms of miRNAs have been detected in serum and hold promise as minimally invasive cancer biomarkers. This study aimed to identify potential circulatory miRNAs that can provide insights into new mechanisms for clinical diagnosis of PCa and can serve as potential biomarkers and/or therapeutic targets. Candidate serum miRNAs were detected by using PCR microarray in a learning set of six African American (AA) and six Caucasian American (CA) PCa patients. Discriminating performance of candidate miRNAs was validated by qRT-PCR in serum samples from 36 AA (24 PCa patients and 12 controls) and 36 CA (16 PCa patients and 20 controls). From the miRNA profiling experiments, three differentially expressed miRNAs (miR-25, miR-101, and miR-628-5p) were selected for future validation. In the validation set, there was an overall low expression of miR-25 (p?<?0.01), miR-101 (p?<?0.001), and miR-628-5p (p?<?0.0001) in serum of PCa patients as compared with normal individuals. Subdivision on the basis of ethnicity showed that serum expression levels of miR-628-5p were significantly downregulated in both AA and CA PCa patients when compared with their respective controls. Our results demonstrate that the three miRNAs, particularly miR-628-5p, may be further developed as a biomarker, which can serve as novel noninvasive biomarker for PCa diagnosis and prognosis.     

Candidate microRNA biomarkers in human colorectal cancer: systematic review profiling studies and experimental validation

Colorectal cancer (CRC) is a major cause of cancer mortality worldwide. There is an urgent need to search for specific and sensitive biomarkers for early diagnosis of CRC. We carried out a comprehensive systematic review of published studies that compared the miRNA expression profiles between CRC tissue and paired neighboring noncancerous colorectal tissue to determine candidate miRNA biomarkers for CRC. A miRNA ranking system that takes the number of comparisons in agreement, total study sizes and direction of differential expression into the consideration was devised and used. One of the most up-regulated miRNAs, miRNA-106a, was consistently reported to be differentially expressed in six studies and the five most down-regulated miRNAs, miR-30a-3p, miR-139, miR-145, miR-125a and miR-133a, were consistently reported to be differentially expressed in four studies. Moreover, we further validated five miRNAs in a clinical setting using qRT-PCR, which demonstrated that miR-106a expression was increased, whereas the expression of miR-30a-3p, miR-145, miR-125a and miR-133a was decreased in the CRC tissues. Therefore, these miRNAs may be the candidates to develop a panel of biomarkers with sufficient sensitivity and specificity for the diagnosis of CRC in a clinical setting.     

Expression of 6 MicroRNAs in Prostate Cancer and Its Significance

OBJECTIVE Numerous microRNAs (miRNAs) are deregulated in human cancers. The experimental evidence supports that miRNAs plays a role in the initiation and progression of human malignancies.The present study was undertaken to evaluate the differential expression of 6 miRNAs as biomarker for early detection of prostate cancer, and then to determine whether the expression profiling of these miRNAs could predict the prognosis of prostate cancer.METHODS The expression profilings of these 6 miRNAs were investigated using the method of locked nucleic acid (LNA)-modified oligonucleotide in situ hybridization (ISH). And the technology of tissue microarray (TMA) was employed using the formalin-fixed, paraffin-embedd (FFPE) specimens taken from 52 patients with prostate carcinoma (PCa) and 38 patients with benign prostatic hyperplasia (BPH).RESULTS The rates of positive expression for 6 miRNAs (miR-15b, miR-16, let-7g, miR- 96,miR-182 and miR-183) were 26.92%,15.38%o, 15.38%, 67.31%, 61.54% and 71.15% in the specimens of prostate cancer, and 57.89%, 76.32%, 68.42%, 44.74%, 31.58%,47.37% in the tissues of benign prostatic hyperplasia, respectively.The expressions of all 6 miRNAs between the prostate cancer and benign prostatic hyperplasia tissues were significantly different (P < 0.05). The positive rate of these 6 miRNAs was significantly related to the Gleason Grading of prostate cancer (P < 0.01). There was no significant correlation between the expression of these miRNAs and age and the concentration of serum PSA of the patient (P > 0.05). We also found that the expression of miR-15b, miR-96 and miR-182 correlated with clinical stages of tumor (P <0.05). The expression of miR-96 correlated with lobus prostatae of tumor invasion (P < 0.01), but the expressions of the remaining five miRNAs were not correlated with that (P > 0.05). In addition, the expression of miR-15b was negatively related to that of miR-96,miR-182 and miR-183, respectively (P < 0.01, r < 0.00).There was a positive correlation among the expressions of miR-96, miR-182 and miR-183 in prostate cancer (P < 0.01, r > 0.00). The expression of miR-16 was positively related to that of miR-let-7g (P < 0.01, r >0.00).CONCLUSION The results suggest that miRNA expression profiling could have relevance to the biological and clinical behavior of prostate cancer, and they might be important biomarkers for early detection and prognostic assessment of prostate cancer.     

Patterns of known and novel small RNAs in human cervical cancer

Recent studies suggest that knowledge of differential expression of microRNAs (miRNA) in cancer may have substantial diagnostic and prognostic value. Here, we use a direct sequencing method to characterize the profiles of miRNAs and other small RNA segments for six human cervical carcinoma cell lines and five normal cervical samples. Of 166 miRNAs expressed in normal cervix and cancer cell lines, we observed significant expression variation of six miRNAs between the two groups. To further show the biological relevance of our findings, we examined the expression level of two significantly varying miRNAs in a panel of 29 matched pairs of human cervical cancer and normal cervical samples. Reduced expression of miR-143 and increased expression of miR-21 were reproducibly displayed in cancer samples, suggesting the potential value of these miRNAs as tumor markers. In addition to the known miRNAs, we found a number of novel miRNAs and an additional set of small RNAs that do not meet miRNA criteria.     

Differential microRNA Expression by Solexa Sequencing in the Sera of Ovarian Cancer Patients

MicroRNAs are a class of small noncoding RNA which play important regulatory roles in a variety of cancers.MiRNA-specific expression profiles have been reported for several pathological conditions. In this study, wecombined large scale parallel Solexa sequencing to identify 11 up-regulated miRNAs and 19 down-regulatedmiRNAs with computational techniques in the sera of ovarian cancer patients while using healthy serum as thecontrol. Among the above, four miRNAs (miR-22, miR-93, miR-106b, miR-451) were validated by quantitativeRT-PCR and found to be significantly aberrantly expressed in the serum of ovarian cancer patients (P<0.05).There were no significant differences between samples from cancer stage Ⅰ/Ⅱ and Ⅲ/Ⅳ. However, the levelsof miR-106b (p=0.003) and miR-451 (p=0.007) were significantly different in those patients under and over 51yearsof age. MiR-451 and miR-93 were also specific when analyzed with reference to different levels of CA125.This study shows that Solexa sequencing provides a promising method for cancer-related miRNA profiling, andselectively expressed miRNAs could be used as potential serum-based biomarkers for ovarian cancer diagnosis.     

miRNA标志物在诊断云南省宣威地区早期非吸烟女性肺癌中的价值

目的初步探索与肿瘤发生相关的miRNA是否可以作为早期诊断云南省宣威地区非吸烟女性肺癌的小分子标志物。方法（1）应用miRNA微阵列芯片分析技术,检测37例宣威地区非吸烟女性肺癌患者和32例非宣威地区非吸烟女性肺癌患者癌组织中的miRNA表达谱,应用实时荧光定量PCR(Q-PCR)对生物芯片分析结果进行验证。（2）实时荧光定量PCR检测16例宣威地区Ⅰ期非吸烟女性肺癌患者和宣威肺癌高发区14例良性病变女性血清中miRNA表达水平。用受试者特征曲线（ROC）来评价血清中miRNA作为诊断宣威地区早期非吸烟女性肺癌患者的敏感度和特异性。结果发现与相邻对应非癌肺组织相比癌组织中有31个miRNA表达存在差异,癌组织中表达差异最显著的miRNA通过实时荧光定量PCR证实。其中miR-21、miR-10a、miR-494、miR-22、miR-141及miR-200b在两组癌组织中的表达水平差异有统计学意义（P<0.05）,且均在16例宣威地区Ⅰ期非吸烟女性肺癌患者和14例良性病变女性血清中稳定表达,其中miR-494、miR-22和miR-200b在两血清中的表达量显著不同（P<0.01）。用其作为分子标志物筛查早期肺癌患者,其敏感度和特异性为85.26%和94.45%。结论从表达的稳定性、敏感度和特异性上看,miR-494、miR-22和miR-200b可作为早期诊断宣威地区非吸烟女性肺癌患者有潜力的小分子标志物。     

Differential expression of microRNAs in early-stage neoplastic transformation in the lungs of F344 rats chronically treated with the tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone

While numerous microRNAs (miRNAs) have been reported to alter their expression levels in human lung cancer tissues compared with normal tissues, the function of these miRNAs and their contribution to the long process of lung cancer development remains largely unknown. We applied a tobacco-specific carcinogen-induced cancer model to investigate the involvement of miRNAs in early lung cancer development, which could also provide information on potential, early biomarkers of lung cancers. Male F344 rats were first chronically treated with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a carcinogen present in tobacco products, for up to 20 weeks. The expression profiles of miRNAs in rat lungs were then determined. As measured by miRNA microarrays and confirmed by Northern blot and real-time polymerase chain reaction analyses, NNK treatment reduced the expression of a number of miRNAs, such as miR-101, miR-126*, miR-199 and miR-34. Significantly, these miRNAs overlap with previously published reports on altered miRNA expression in human lung cancer samples. These miRNAs might, therefore, represent early-response miRNAs that signify the molecular changes associated with pulmonary tumorigenesis. Moreover, we identified cytochrome P450 (CYP) 2A3, a critical enzyme in rat lungs that activates NNK to render it carcinogenic, as a potential target of miR-126*. NNK treatment in rats repressed miR-126* but induced CYP2A3 expression, a mechanism that may potentiate the oncogenic effects of NNK.     

Plasma Circulating Mirnas Profiling for Identification of Potential Breast Cancer Early Detection Biomarkers

Objective: This study aimed to characterize the miRNA expression profiles from plasma samples of our local breast cancer patients in comparison to healthy control by using miRNA PCR Array. Methods: In this study, plasma miRNA profiles from eight early-stage breast cancer patients and nine age-matched (± 2 years) healthy controls were characterized by miRNA array-based approach, followed by differential gene expression analysis, Independent T-test and construction of Receiver Operating Characteristic (ROC) curve to determine the capability of the assays to discriminate between breast cancer and the healthy control. Results: Based on the 372-miRNAs microarray profiling, a set of 40 differential miRNAs was extracted regarding to the fold change value at 2 and above. We further sub grouped 40 miRNAs of breast cancer patients that were significantly expressed at 2-fold change and higher. In this set, we discovered that 24 miRNAs were significantly upregulated and 16 miRNAs were significantly downregulated in breast cancer patients, as compared to the miRNA expression of healthy subjects. ROC curve analysis revealed that seven miRNAs (miR-125b-5p, miR-142-3p, miR-145-5p, miR-193a-5p, miR-27b-3p, miR-22-5p and miR-423-5p) had area under curve (AUC) value > 0.7 (AUC p-value < 0.05). Overlapping findings from differential gene expression analysis, ROC analysis, and Independent T-Test resulted in three miRNAs (miR-27b-3p, miR-22-5p, miR-145-5p). Cohen’s effect size for these three miRNAs was large with d value are more than 0.95. Conclusion: miR-27b-3p, miR-22-5p, miR-145-5p could be potential biomarkers to distinguish breast cancer patients from healthy controls. A validation study for these three miRNAs in an external set of samples is ongoing.     

Association of miR-193b Down-regulation and miR-196a up-Regulation with Clinicopathological Features and Prognosis in Gastric Cancer

Dysregulated expression of microRNAs (miRNAs) has been shown to be closely associated with tumordevelopment, progression, and carcinogenesis. However, their clinical implications for gastric cancer remainelusive. To investigate the hypothesis that genome-wide alternations of miRNAs differentiate gastric cancer tissuesfrom those matched adjacent non-tumor tissues (ANTTs), miRNA arrays were employed to examine miRNAexpression profiles for the 5-pair discovery stage, and the quantitative real-time polymerase chain reaction (qRTPCR)was applied to validate candidate miRNAs for 48-pair validation stage. Furthermore, the relationshipbetween altered miRNA and clinicopathological features and prognosis of gastric cancer was explored. Amonga total of 1,146 miRNAs analyzed, 16 miRNAs were found to be significantly different expressed in tissues fromgastric cancer compared to ANTTs (p<0.05). qRT-PCR further confirmed the variation in expression of miR-193band miR-196a in the validation stage. Down-expression of miR-193b was significantly correlated with Laurentype, differentiation, UICC stage, invasion, and metastasis of gastric cancer (p<0.05), while over-expression ofmiR-196a was significantly associated with poor differentiation (p=0.022). Moreover, binary logistic regressionanalysis demonstrated that the UICC stage was a significant risk factor for down-expression of miR-193b (adjustedOR=8.69; 95%CI=1.06-56.91; p=0.043). Additionally, Kaplan-Meier survival curves indicated that patientswith a high fold-change of down-regulated miR-193b had a significantly shorter survival time (n=19; mediansurvival=29 months) compared to patients with a low fold-change of down-regulated miR-193b (n=29; mediansurvival=54 months) (p=0.001). Overall survival time of patients with a low fold-change of up-regulated miR-196a (n=27; median survival=52 months) was significantly longer than that of patients with a high fold-changeof up-regulated miR-196a (n=21; median survival=46 months) (p=0.003). Hence, miR-193b and miR-196a maybe applied as novel and promising prognostic markers in gastric cancer.     

MicroRNA-143 is a putative predictive factor for the response to fluoropyrimidine-based chemotherapy in patients with metastatic colorectal cancer

Approximately half of the colorectal cancer (CRC) patients develop metastatic disease. Fluoropyrimidine-based chemotherapy forms the backbone of treatment in these patients. However, the response to this therapy varies between individuals. Therefore, an important challenge in CRC research is to identify biomarkers that are predictive of this response. In this study, we explored the potential of miRNAs, and the miRNA producing protein Dicer, as biomarkers that can predict chemo-sensitivity to fluoropyrimidine chemotherapy in patients with metastatic colorectal cancer (mCRC). We analyzed the levels of 22 miRNAs and the Dicer protein in primary tumors from patients with mCRC who were treated with first-line capecitabine monotherapy within the CAIRO trial of the Dutch Colorectal Cancer Group. Correlation between the expression status of miRNAs or Dicer in primary tumors and the progression free survival (PFS) were investigated. Patients with low expression of miR-143 in their primary tumor had increased median PFS compared to those with high expression of miR-143. Furthermore, FXYD3, an ion transport regulator and a putative target of miR-143, also showed an association with PFS. These findings warrant further studies to investigate the relationship between miR-143, FXYD3 and fluoropyrimidines, and the clinical utility of miR-143 as biomarker.