MiR-204 regulates type 1 IP3R to control vascular smooth muscle cell contractility and blood pressure

MiR-204 is expressed in vascular smooth muscle cells (VSMC). However, its role in VSMC contraction is not known. We determined if miR-204 controls VSMC contractility and blood pressure through regulation of sarcoplasmic reticulum (SR) calcium (Ca²⁺) release. Systolic blood pressure (SBP) and vasoreactivity to VSMC contractile agonists (phenylephrine (PE), thromboxane analogue (U46619), endothelin-1 (ET-1), angiotensin-II (Ang II) and norepinephrine (NE) were compared in aortas and mesenteric resistance arteries (MRA) from miR-204^−/− mice and wildtype mice (WT). There was no difference in basal systolic blood pressure (SBP) between the two genotypes; however, hypertensive response to Ang II was significantly greater in miR-204^−/− mice compared to WT mice. Aortas and MRA of miR-204^−/− mice had heightened contractility to all VSMC agonists. In silico algorithms predicted the type 1 Inositol 1, 4, 5-trisphosphate receptor (IP₃R1) as a target of miR-204. Aortas and MRA of miR-204^−/− mice had higher expression of IP₃R1 compared to WT mice. Difference in agonist-induced vasoconstriction between miR-204^−/− and WT mice was abolished with pharmacologic inhibition of IP₃R1. Furthermore, Ang II-induced aortic IP₃R1 was greater in miR-204^−/− mice compared to WT mice. In addition, difference in aortic vasoconstriction to VSMC agonists between miR-204^−/− and WT mice persisted after Ang II infusion. Inhibition of miR-204 in VSMC in vitro increased IP₃R1, and boosted SR Ca²⁺ release in response to PE, while overexpression of miR-204 downregulated IP₃R1. Finally, a sequence-specific nucleotide blocker that targets the miR-204-IP₃R1 interaction rescued miR-204-induced downregulation of IP₃R1. We conclude that miR-204 controls VSMC contractility and blood pressure through IP₃R1-dependent regulation of SR calcium release.     

MicroRNA-206 has a bright application prospect in the diagnosis of cases with oral cancer

Previous studies have shown that microRNA-206 (miR-206) exhibits anti-tumour properties in various tumours. Nevertheless, diagnostic significance of miR-206 in oral cancer is still poorly known. Our research was carried out to explore the performance of miR-206 in the diagnosis of oral cancer. Quantitative real-time polymerase chain reaction (qRT-PCR) method was adopted to measure the level of miR-206 in serum specimens from oral cancer cases and control individuals. Chi-square test was performed to analyse the correlation between miR-206 level and clinicopathological parameters of the cases. Receiver operating characteristic (ROC) curve was constituted to assess diagnostic accuracy of miR-206 in oral cancer. Serum miR-206 level in oral cancer patients was significantly lower than that in control individuals (P < .001). miR-206 expression was obviously related to T classification (P = .033), TNM stage (P = .008) and lymph node metastasis (P = .028). The area under the curve (AUC) of the ROC curve was 0.846 (95% CI = 0.797-0.896, P < .001) with a specificity of 72.7% and a sensitivity of 81.2%. It revealed that miR-206 might be a non-invasive indicator in differentiating oral cancer cases from control individuals. Down-regulation of miR-206 is related to the development of oral cancer. Serum miR-206 might be an effective indicator for early detection of oral cancer.     

FZD6 expression is negatively regulated by miR-199a-5p in human colorectal cancer

Colorectal cancer (CRC), the third most common cancer worldwide, also has the highest rate of cancer-related morbidity and mortality. WNT signaling is initiated by binding of WNT to various receptors, including frizzleds (FZDs), and plays a critical role in CRC and other tumor development by regulating proliferation, differentiation, migration, apoptosis, and polarity. Among the members of the FZD family, FZD6 is broadly expressed in various tissues, and its overexpression has been reported in several cancers, suggesting an important role in cancer development. In this study, we investigated the expression of FZD6 in patients with CRC and found it to be increased in tumors, as compared to paired adjacent non-tumor tissues. Additionally, we found that FZD6 expression was negatively regulated by miR199a5p in CRC cells. These results suggest that overexpression of FZD6, mediated by reduced expression of miR-199a-5p, may play an important role in the development of CRC. [BMB Reports 2015; 48(6): 360-366]     

MicroRNA 421 suppresses DPC4/Smad4 in pancreatic cancer

MicroRNAs (miRNAs) have emerged as important regulators in the development of pancreatic cancer and may be a valuable therapeutic application. DPC4/Smad4 is a critical tumor suppressor involved in the progression of pancreatic cancer, but few studies have been conducted to determine its relationship with miRNAs. In this study, we identify miR-421 as a potential regulator of DPC4/Smad4. We find that in human clinical specimens of pancreatic cancer miR-421 is aberrantly upregulated while DPC4/Smad4 is strongly repressed, and their levels of expression are inversely correlated. Moreover, ectopic expression of miR-421 significantly decreases DPC4/Smad4 protein level in pancreatic cancer cell lines and simultaneously promotes cell proliferation and colony formation in vitro. Our findings identify miR-421 as a potent regulator of DPC4/Smad4, which may provide a novel therapeutic strategy for treatment of DPC4/Smad4-driven pancreatic cancer.     

miR-106a-5p调控 PTEN对鼻咽癌细胞SUNE2增殖和迁移的抑制作用研究

目的研究miR-106a-5p对鼻咽癌细胞SUNE2增殖和迁移的影响。 方法将体外培养的鼻咽癌细胞SUNE2分成对照组（细胞未做任何处理）、Anti-NC组（转染阴性对照抑制剂）、Anti-miR-106a-5p组（转染miR-106a-5p抑制剂）、后期实验另设Anti-miR-106a-5p-inhibitor+si-NC组（转染miR-106a-5p抑制剂、siRNA阴性对照）、Anti-miR-106a-5p-inhibitor+si-PTEN组（转染miR-106a-5p抑制剂、PTEN siRNA）,采用Realtime PCR测定miR-106a-5p表达,MTT法检测增殖,Transwell小室检测细胞侵袭和迁移能力变化,用Western blot方法测定vimentin、E-cadherin蛋白表达。在线靶基因预测软件预测miR-106a-5p的靶基因可能为PTEN,双荧光素酶报告系统鉴定miR-106a-5p和PTEN的靶向关系。两组间比较用独立样本t检验,多组间比较采用单因素方差分析,组间两两比较采用LSD-t检验。 结果与正常鼻咽上皮细胞NP69比较,鼻咽癌细胞CNE-2、HK1、SUNE2中miR-106a-5p水平（1.00±0.11比1.84±0.13、2.19±0.14、2.87±0.25）升高,差异具有统计学意义（P < 0.05）。与对照组、Anti-NC组比较,Anti-miR-106a-5p组鼻咽癌细胞miR-106a-5p水平（1.00±0.10、0.99±0.12比0.76±0.08）降低,OD值（0.56±0.05、0.57±0.04比0.32±0.02）,细胞侵袭数[（128.47±11.65）个、（129.84±10.93）个比（85.12±6.75）个],迁移数[（182.51±14.81）个、（180.68±17.64）个比（122.01±11.62）个],vimentin蛋白表达水平（0.84±0.09、0.82±0.07比0.30±0.05）降低,E-cadherin蛋白表达水平（0.29±0.04、0.28±0.05比0.76±0.08）升高,差异具有统计学意义（P均< 0.05）。与Anti-miR-106a-inhibitor+si-NC组比较,Anti-miR-106a-inhibitor+si-PTEN组细胞OD值（0.33±0.03比0.52±0.05）、侵袭数[（84.16±5.91）个比（105.79±8.63）个]、迁移数[（118.42±10.25）个比（164.28±12.05）个]、vimentin蛋白表达水平（0.34±0.06比0.68±0.05）均升高,E-cadherin蛋白表达水平（0.72±0.06比0.29±0.05）降低,差异具有统计学意义（P均< 0.05）。 结论miR-106a-5p可通过靶向调控PTEN抑制鼻咽癌细胞SUNE2增殖和迁移潜能。     

miR‐126 reduces trastuzumab resistance by targeting PIK3R2 and regulating AKT/mTOR pathway in breast cancer cells

MicroRNAs (miRNAs) have been found to play a key role in drug resistance. In the current study, we aimed to explore the potential role of miR‐126 in trastuzumab resistance in breast cancer cells. We found that the trastuzumab‐resistant cell lines SKBR3/TR and BT474/TR had low expression of miR‐126 and increased ability to migrate and invade. The resistance, invasion and mobilization abilities of the cells resistant to trastuzumab were reduced by ectopic expression of miR‐126 mimics. In comparison, inhibition of miR‐126 in SKBR3 parental cells had the opposite effect of an increased resistance to trastuzumab as well as invasion and migration. It was also found that miR‐126 directly targets PIK3R2 in breast cancer cells. PIK3R2‐knockdown cells showed decreased resistance to trastuzumab, while overexpression of PIK3R2 increased trastuzumab resistance. In addition, our finding showed that overexpression of miR‐126 reduced resistance to trastuzumab in the trastuzumab‐resistant cells and that inhibition of the PIK3R2/PI3K/AKT/mTOR signalling pathway was involved in this effect. SKBR3/TR cells also showed increased sensitivity to trastuzumab mediated by miR‐126 in vivo. In conclusion, the above findings demonstrated that overexpression of miR‐126 or down‐regulation of its target gene may be a potential approach to overcome trastuzumab resistance in breast cancer cells.     

miR-195通过靶向调控趋化因子5促进胃癌细胞增殖、转移及侵袭的实验研究

目的:研究miR-195通过靶向调控趋化因子5促进胃癌细胞增殖、转移及侵袭的分子机制。方法:选取MGC803及NCI-N87细胞,根据转染不同分为:miR-NC组(空质粒),miR-195-mimics组(模拟序列)。实时荧光定量PCR法检测miR-195表达;MTT检测细胞增殖能力;Transwell侵袭实验检测细胞侵袭力;细胞划痕实验检测细胞转移能力;流式细胞术检测细胞凋亡情况;Western blot检测chemokine 5表达水平;Spearman相关分析miR-195及chemokine 5相关性。荧光素酶实验验证miR-195与chemokine 5的靶向关系。结果:miR-195-mimics组细胞miR-195水平高于miR-NC组(P0.05);miR-195 mimics组第1、2、3、4 d细胞活力低于miR-NC组(P0.05);miR-195 mimics组G1细胞高于miR-NC组,G2期、S期细胞低于miR-NC组,G2/S期细胞比值低于miR-NC组(P0.05);miR-195 mimics组划痕距离大于miR-NC组(P0.05);miR-195 mimics组细胞侵袭数低于miR-NC组(P0.05);miR-195-mimics组细chemokine 5蛋白含量低于miR-NC组(P0.05);miR-195 m RNA水平与chemokine 5蛋白含量负相关(r=-0.398,P=0.00);miR-195可直接靶向chemokine 5。结论:miR-195可通过靶向chemokine 5促进胃癌MGC803及NCI-N87细胞的增殖、转移及侵袭。     

MiR-210在缺氧中调控机制的研究进展

MicroRNA(miRNA)是一类包含21-25个核苷酸的单链非编码小RNA.研究表明,miR-210可直接抑制线粒体内铁硫蛋白(Fe-S)的支架蛋白ISCUl/2的表达从而抑制线粒体代谢;miR-210对DNA损伤修复基因-RAD家族有抑制作用,减弱了DNA修复能力;miR-210可以通过调节E2F3、纤维母细胞生长因子受体1(FGFRL1)、同源域基因A1(HOXA1)等阻止细胞增殖,调控细胞周期;缺氧刺激可上调miR-210表达,这对促进血管再生有重要作用.miR-210的表达受缺氧诱导,调控缺氧反应相关基因的表达,提示miR-210有可能成为诊治包括缺血性损伤、肿瘤在内等多种疾病的新靶点.