miRNAS in cardiovascular diseases: potential biomarkers, therapeutic targets and challenges.

Cardiovascular diseases (CVD) are the leading cause of morbidity and mortality in the world. Although considerable progress has been made in the diagnosis, treatment and prognosis of CVD, there is still a critical need for novel diagnostic biomarkers and new therapeutic interventions to decrease the incidence of this disease. Recently, there is increasing evidence that circulating miRNAs (miRNAs), i.e. endogenous, stable, single-stranded, short, non-coding RNAs, can be used as diagnostic biomarkers for CVD. Furthermore, miRNAs represent potential novel therapeutic targets for several cardiovascular disorders. In this review we provides an overview of the effects of several CVD; including heart failure, acute myocardial infarction, arrhythmias and pulmonary hypertension; on levels of circulating miRNAs. In addition, the use of miRNA as therapeutic targets is also discussed, as well as challenges and recommendations in their use in the diagnosis of CVD.

miR-938 promotes colorectal cancer cell proliferation via targeting tumor suppressor PHLPP2.

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Although the development of therapy approaches, the outcome of CRC patients still is poor, understanding the biological mechanism of CRC progression is critical to improve the treatment strategies. miRNAs regulate CRC progression, we found miR-938 was upregulated in CRC tissues and cells, MTT assay, colony formation assay and soft agar growth assay suggested miR-938 overexpression promoted CRC cell proliferation, miR-938 knockdown inhibited CRC cell proliferation. Tumor suppressor PH domain Leucine-rich-repeats Protein Phosphatase 2 (PHLPP2) was a target of miR-938, miR-938 inhibited PHLPP2, luciferase activity assay suggested miR-938 directly bound to the 3'UTR of PHLPP2, meanwhile, we found miR-938 promoted c-Myc and Cyclin D1 expression, confirming miR-938 promoted CRC cell proliferation. Double knockdown of miR-938 and PHLPP2 promoted CRC cell proliferation, suggesting miR-938 promoted CRC cell proliferation by inhibiting PHLPP2.

Desmin detection by facile prepared carbon quantum dots for early screening of colorectal cancer.

Th aim of this study was to develop a new facile chemical method for early screening of colorectal cancer.The -C(O)OH groups modified Carbon Quantum Dots (CQDs) were prepared by an facile innovative route of acid attacking on carbon nanotubes (CNTs). The -C(O)OH groups were further transported into -C(O)Cl groups by SOCl2 treating. The obtained ClCQDs were conjugated onto the anti-Desmin, which were applied for testing the Desmin concentration in serum by using linearly fitted relationship with photoluminescence (PL) intensity.The obtained carbon quantum dots are quasispherical graphite nanocrystals with photoluminescence at about 455 nm. The Desmin with concentration of 1 ng/mL can lead to a decrease of PL intensity for anti-Desmin conjugated CQDs with good linearity. This assay had good specificity for Desmin with in interferential substances of immunoglobulin G (IgG), alpha fetoprotein (AFP), and carcinoembryoic antigen (CEA).A new facile acid attack method was developed to prepare ClCQDs, which could conjugate onto the anti-Desmin for detection of Desmin in serum with high sensitivity and specificity. As the detection limit is lower than 1 ng/ mL, this work provides a promising strategy for the evaluation of colorectal cancer risk with low cost and excellent sensing performance.

MicroRNA-766 targeting regulation of SOX6 expression promoted cell proliferation of human colorectal cancer.

MicroRNAs (miRNAs) have emerged as important regulators of cancer-cell biological processes. Previous studies have shown that miR-766 plays an important role in a variety of biological processes in various human cancers. However, the underlying mechanism of miR-766 in colorectal cancer (CRC) cells remains unclear. In this study, we investigated miR-766's role in CRC cell proliferation. Polymerase chain reaction results showed that miR-766 expression was significantly upregulated in CRC tissues and cells. Ectopic expression of miR-766 promoted cell growth and anchorage-independent growth in CRC cells. Bioinformatic analysis predicted SOX6, a potential target of miR-766, acting as a tumor suppressor. Luciferase reporter assay results demonstrated that miR-766 directly bound to the 3'-untranslated region of SOX6. Overexpression of miR-766 suppressed SOX6 expression, resulting in the downregulation of p21 and upregulation of cyclin D1. In a further experiment, SOX6-silenced SW480 cells transfected with miR-766 promoted cell growth, suggesting that downregulation of SOX6 was required for miR-766-induced CRC cell proliferation. Taken together, these results suggested that miR-766 represents an onco-miRNA and participates in the development of CRC by modulating SOX6 expression.

Dual­sensitive HRE/Egr1 promoter regulates Smac overexpression and enhances radiation­induced A549 human lung adenocarcinoma cell death under hypoxia.

The aim of this study was to construct an expression vector carrying the hypoxia/radiation dual­sensitive chimeric hypoxia response element (HRE)/early growth response 1 (Egr­1) promoter in order to overexpress the therapeutic second mitochondria­derived activator of caspases (Smac). Using this expression vector, the present study aimed to explore the molecular mechanism underlying radiotherapy­induced A549 human lung adenocarcinoma cell death and apoptosis under hypoxia. The plasmids, pcDNA3.1­Egr1­Smac (pE­Smac) and pcDNA3.1­HRE/Egr-1­Smac (pH/E­Smac), were constructed and transfected into A549 human lung adenocarcinoma cells using the liposome method. CoCl2 was used to chemically simulate hypoxia, followed by the administration of 2 Gy X­ray irradiation. An MTT assay was performed to detect cell proliferation and an Annexin V­fluorescein isothiocyanate apoptosis detection kit was used to detect apoptosis. Quantitative polymerase chain reaction and western blot analyses were used for the detection of mRNA and protein expression, respectively. Infection with the pE­Smac and pH/E­Smac plasmids in combination with radiation and/or hypoxia was observed to enhance the expression of Smac. Furthermore, Smac overexpression was found to enhance the radiation­induced inhibition of cell proliferation and promotion of cycle arrest and apoptosis. The cytochrome c/caspase­9/caspase­3 pathway was identified to be involved in this regulation of apoptosis. Plasmid infection in combination with X­ray irradiation was found to markedly induce cell death under hypoxia. In conclusion, the hypoxia/radiation dual­sensitive chimeric HRE/Egr­1 promoter was observed to enhance the expression of the therapeutic Smac, as well as enhance the radiation­induced inhibition of cell proliferation and promotion of cycle arrest and apoptosis under hypoxia. This apoptosis was found to involve the mitochondrial pathway.

The tumor suppressor gene RhoBTB1 is a novel target of miR-31 in human colon cancer.

miRNAs are a class of endogenous non-coding RNA, which can regulate downstream target genes through binding to the 3'UTR of those genes. Numerous studies have indicated that abnormal expression of miRNAs is implicated in tumor development. Aberrant expression of miR-31 has been found in various cancers, including colorectal cancer. Here, we show that miR-31 is upregulated in human colon cancer tissues and cell lines, and that repression of miR-31 inhibited colon cancer cell proliferation and colony formation in soft agarose. To further elucidate the mechanism underlying the role of miR-31 in promoting colon cancer, we used online miRNA target prediction databases and found that the tumor suppressor RhoTBT1 may be a target of miR-31. Imunohistochemistry assay revealed that RhoBTB1 was significantly decreased in HT29 cells. In addition, ectopic expression of miR-31 reduced RhoBTB1 in the colon cancer cell line HT29. The results suggested that suppression of RhoBTB1 may be responsible for colon tumorigenesis, which was inhibited directly by miR-31. The results of MTT and soft agarose colony-formation assays showed that knockdown of RhoBTB1 by RNAi induced cell proliferation, and colony formation in soft agarose, which mimicked the function of miR-31. This further suggested that suppression of RhoBTB1 was responsible for colon tumorigenesis. In conclusion, we found that miR-31 acts as an oncogene in colon cancer and identified RhoBTB1 as a new target of miR-31 further study demonstrated that miR-31 contributed to the development of colon cancer at least partly by targeting RhoBTB1.