MicroRNA in pancreatic adenocarcinoma: predictive/prognostic biomarkers or therapeutic targets?

Pancreatic ductal adenocarcinoma (PDAC) is a tumor with a poor prognosis, short overall survival and few chemotherapeutic choices. MicroRNAs (miRNAs) are non-coding, single-stranded RNAs of around 22 nucleotides involved in the pathogenic mechanisms of carcinogenesis and metastasis. They have been studied in many tumors in order to identify potential diagnostic, prognostic or therapeutic targets. In the current literature, many studies have analyzed the role of miRNAs in PDAC. In fact, the absence of appropriate biomarkers, the difficultly of early detection of this tumor, and the lack of effective chemotherapy in patients with unresectable disease have focused attention on miRNAs as new, interesting advance in this malignancy.In this review we analyzed the role of miRNAs in PDAC in order to understand the mechanisms of action and the difference between the onco-miRNA and the tumor suppressor miRNA. We also reviewed all the data related to the use of these molecules as predictive as well as prognostic biomarkers in the course of the disease.Finally, the possible therapeutic use of miRNAs or anti-miRNAs in PDAC is also discussed.In conclusion, although there is still no clinical application for these molecules in PDAC, it is our opinion that the preclinical evidence of the role of specific miRNAs in carcinogenesis, the possibility of using miRNAs as diagnostic or prognostic biomarkers, and their potential therapeutic role, warrant future studies in PDAC.     

Inhibition of miR-21 restores RANKL/OPG ratio in multiple myeloma-derived bone marrow stromal cells and impairs the resorbing activity of mature osteoclasts

miR-21 is an oncogenic microRNA (miRNA) with an emerging role as therapeutic target in human malignancies, including multiple myeloma (MM). Here we investigated whether miR-21 is involved in MM-related bone disease (BD). We found that miR-21 expression is dramatically enhanced, while osteoprotegerin (OPG) is strongly reduced, in bone marrow stromal cells (BMSCs) adherent to MM cells. On this basis, we validated the 3′UTR of OPG mRNA as miR-21 target. Constitutive miR-21 inhibition in lentiviral-transduced BMSCs adherent to MM cells restored OPG expression and secretion. Interestingly, miR-21 inhibition reduced RANKL production by BMSCs. Overexpression of protein inhibitor of activated STAT3 (PIAS3), which is a direct and validated target of miR-21, antagonized STAT3-mediated RANKL gene activation. Finally, we demonstrate that constitutive expression of miR-21 inhibitors in BMSCs restores RANKL/OPG balance and dramatically impairs the resorbing activity of mature osteoclasts. Taken together, our data provide proof-of-concept that miR-21 overexpression within MM-microenviroment plays a crucial role in bone resorption/apposition balance, supporting the design of innovative miR-21 inhibition-based strategies for MM-related BD.     

PAQR3: a novel tumor suppressor gene

PAQR3, also known as RKTG (Raf kinase trapping to Golgi), is a member of the progestin and adipoQ receptor (PAQR) family. The role of PAQR3 as a tumor suppressor has recently been established in different types of human cancer in which PAQR3 exerts its biological function through negative regulation of the oncogenic Raf/MEK/ERK signaling. Multiple studies have found that PAQR3 downregulation frequently occurs in human cancers and is very often associated with tumor progression and shortened patients’ survival. Moreover, restoring the expression of PAQR3 could induce apoptosis and inhibit proliferation and invasiveness of cancer cells. Downregulation of PAQR3 by oncogenic microRNAs has also been reported. In this review, we summarized current knowledge concerning the role of PAQR3 in tumor development. To our knowledge, this is the first review on the role of this novel tumor suppressor.     

Circulating miRNAs is a potential marker for gefitinib sensitivity and correlation with EGFR mutational status in human lung cancers

miRNA expression is deregulated in non-small cell lung cancer (NSCLC), and some miRNAs are associated with gefitinib sensitivity. Here, we investigated if circulating miRNAs could be a useful biomarker for the prediction of EGFR mutation and the patient’s prognosis. The differential miRNAs related to gefitinib sensitivity were screened and identified by microRNA array. Using Taqman-based real-time RT-PCR, we analyzed the expression of selected miRNAs in tumor tissues and plasma of 150 NSCLC patients. Kaplan-Meier survival analysis and Cox proportional hazards regression were used to determine the association between miRNAs expression and survival. Receiver operating characteristic curve analysis was also performed. Compared with PC9 cell line, 41 microRNAs detected by microarray were significantly differentially expressed in A549 and H1299 cells. The 5 selected hsa-miRNAs were all found differently expressed between wild and mutant EGFR carriers (all P<0.01). Down-regulation of 5 selected miRNAs were independently associated with lymphatic invasion (all P<0.01) and clinical stage (all P<0.01), respectively. Both down-regulation of has-miR-195 (P=0.012) and has-miR-21 (P=0.004) were associated with poor differentiation. All up-regulation of 5 has-miRNAs were associated with smoking (All P<0.05). 5 hsa-miRNAs were up-regulated both in plasma and tissue samples. A model including 4 hsa-miRNAs may predict EGFR mutational status and gefitinib-sensitivity (both AUC: 0.869). Plasma levels of has-miR-125b expression were associated with disease-free survival (P=0.033) and overall survival in the patients (P=0.028). In a word, Circulating 5 selected miRNAs may especially be useful in predicting EGFR mutation, and circulating hsa-miR-125b may have prognostic values in NSCLC patients.     

血清miR-146a／b实时荧光定量分析及其作为分子标志物的初步评价

目的：以特异性调节Toll样受体信号通路的miR-146a／b为检测靶标,建立血清miRNAs分子荧光定量检测方法,并对其作为血清炎症分子标志物的潜在价值进行初步评价。方法：采集正常体质量儿童血清20例（对照组）、超重儿童血清20例（超重组）、肥胖儿童血清20例（肥胖组）及健康成年人血清50例（健康成人组）,酚-氯仿法提取血清总RNAs,SYBRGreen实时荧光定量技术定量检测血清中miR-146a／b拷贝数,GraphpadPrism5．0软件进行统计分析并绘图。结果：对照组血清中miR-146a的拷贝数显著低于超重组（P=-0．0061）和肥胖组（P=-0．0262）,超重组和肥胖组之间差异无统计学意义（P=0．0656）。miR-146a表达量的受试者工作特征曲线下面积（AUC）分析显示：对照组vs超重组AUC=O．8475,P=-0．0002;对照组vs肥胖组AUC=0．6050,P=-0．2560;超重组vs肥胖组AUC=0．5475,P=0．6073。miR-146b与miR-146a呈不同表达趋势,超重组儿童血清miR-146b拷贝数显著高于对照组（P=-0．0090）和肥胖组儿童（P=0．0023）,肥胖组儿童血清中miR-146b的拷贝数均值虽略低于对照组,但差异无统计学意义（P=-0．1556）。miR-146b表达量的AUC分析显示：正常组vs超重组AUC=0．7425,P=O．0087;正常组vs肥胖组AUC=0．6325,P=0．1517;超重组vs肥胖组AUC=0．7825,P=0．0023。miR．146a／b拷贝数值变异系数（CV）大：对照组、超重组和肥胖组儿童血清中miR。146a拷贝数的cv值分别为80．94％、110．94％、175．88％;miR-146b拷贝数的cV值分别为164．11％、189．72％、152．00％。在健康成人血清中miR-146a／b呈现相近表达模式,miR-146a和miR-146b的cV值分别是37．86％、74．82％。结论：miR-146a在对照组、超重组和肥胖组的表达量变化显示其与儿童肥胖具有-定相关性,可以从整体水平说明miR-146a与体内炎症水平呈正相关关系,但是由于其在血清中拷贝数值变异较大且各组问无明确分界,不能确定其参考值范围。因此,血清miR-146a／b拷贝数差异不足以用于临床个体化诊断,血清miR-146a／b作为炎症相关分子标志物的价值尚需进一步探讨。     

Expression profiles of miRNAs in human pancreatic cancer cell lines

Objective： To analyze initially the differences of miRNAs expression profiles in human pancreatic cancer cell lines by microarray technique. Methods： A total of 743 probes were designed according to the known miRNAs sequences of human, mice, and rats. miRNAs microarray was manufactured and its credibility was verified. Total RNAs were extracted and miRNAs were separated from human pancreatic cancer cell lines （SW1990, Capan-2, BxPC-3, Aspc-1, and Pancl） and immortal human pancreatic duct epithelial cell line H6C7. They were labeled with T4 RNA ligase, then were hybridized with microarray. Through array scan and analysis, miRNAs expression profiles in pancreatic cancer were obtained. The results were verified by Northern blotting and RT-PCR. Results： A total of 63 rniRNAs related to pancreatic cancer were found to be differentially expressed in 5 pancreatic cancer cell lines, including 25 down-regulated and 38 up-regulated miRNAs. Expressions of mir-21 and let-7 were also confirmed： Conclusion： The results suggested that miRNAs expression profiles could be found in pancreatic cancer cells.