Ultrasound-Targeted Microbubble Destruction Enhances the Inhibitive Efficacy of miR-21 Silencing in HeLa Cells

Indirect and sensitive determination of microRNAs by magnetic field-assisted capillary sieving electrophoresis combined with catalytic hairpin assembly

To determine multiple microRNAs (miRNAs) from cells simultaneously is essential for understanding biological functions. Capillary electrophoresis (CE) can simultaneously determine multiple miRNAs by separation. Nevertheless, similar lengths and low concentrations in cells make miRNAs hard to separate and detect. In this study, CE with laser-induced fluorescence detection was combined with catalytic hairpin assembly (CHA) to determine three miRNAs, miR-21, miR-31, and miR-122. The amplification products of CHA, which were DNA duplexes, were designed to have different lengths for different miRNAs. This allowed for easy separation of the duplexes of different miRNAs by CE. The indirect determination of miRNAs was then achieved by separating and detecting these duplexes. A magnetic field was first applied on the capillary sieving electrophoresis to assist in the separation of the duplexes. Under the optimal conditions, the three duplexes could be completely separated within 2.5 min with the detection limits of miRNAs in the range 1.12-4.05 × 10-15 M. MiR-21 and miR-31 were successfully determined from Hela cells, while miR-122 was determined from chicken livers by this method. The recoveries ranged from 97.5% to 118%. The developed method was sensitive and reliable for miRNA determination.

Pre-clinical and clinical importance of miR-21 in human cancers: Tumorigenesis, therapy response, delivery approaches and targeting agents

The field of non-coding RNA (ncRNA) has made significant progress in understanding the pathogenesis of diseases and has broadened our knowledge towards their targeting, especially in cancer therapy. ncRNAs are a large family of RNAs with microRNAs (miRNAs) being one kind of endogenous RNA which lack encoded proteins. By now, miRNAs have been well-coined in pathogenesis and development of cancer. The current review focuses on the role of miR-21 in cancers and its association with tumor progression. miR-21 has both oncogenic and onco-suppressor functions and most of the experiments are in agreement with the tumor-promoting function of this miRNA. miR-21 primarily decreases PTEN expression to induce PI3K/Akt signaling in cancer progression. Overexpression of miR-21 inhibits apoptosis and is vital for inducing pro-survival autophagy. miR-21 is vital for metabolic reprogramming and can induce glycolysis to enhance tumor progression. miR-21 stimulates EMT mechanisms and increases expression of MMP-2 and MMP-9 thereby elevating tumor metastasis. miR-21 is a target of anti-cancer agents such as curcumin and curcumol and its down-regulation impairs tumor progression. Upregulation of miR-21 results in cancer resistance to chemotherapy and radiotherapy. Increasing evidence has revealed the role of miR-21 as a biomarker as it is present in both the serum and exosomes making them beneficial biomarkers for non-invasive diagnosis of cancer.

Nanoflare Couple: Multiplexed mRNA Imaging and Logic-Controlled Combinational Therapy

Theranostics, which combines both diagnostic and therapeutic capabilities in one dose, has always been an intractable challenge in personalized cancer treatment. Herein, a versatile nanotheranostic platform "nanoflare couple (NC)" has been developed for in situ multiplex cancer-related mRNA imaging and subsequent logic-controlled aggregation of gold nanoparticles, leading to gene therapy and photothermal therapy upon irradiation with infrared light. As a proof of concept, TK1 and survivin mRNAs that are highly expressed in most tumor tissues are selected as endogenous cancer indicators and therapy triggers to design the NC. Mice bearing breast cancer cells MCF-7 are prepared as a model to test its efficacy. The in vitro and in vivo assays validate that the NC show the capability for multiplexed mRNA imaging and high efficiency for logic-controlled combinational therapy of breast cancer.

Effect of Gambogic Acid-Loaded Porous-Lipid/PLGA Microbubbles in Combination With Ultrasound-Triggered Microbubble Destruction on Human Glioma

Gambogic acid (GA) is a highly effective antitumor agent, and it is used for the treatment of a wide range of cancers. It is challenging to deliver drugs to the central nervous system due to the inability of GA to cross the blood-brain barrier (BBB). Studies have shown that ultrasound-targeted microbubble destruction can be used for transient and reversible BBB disruption, significantly facilitating intracerebral drug delivery. We first prepared GA-loaded porous-lipid microbubbles (GA porous-lipid/PLGA MBs), and an in vitro BBB model was established. The cell viability was detected by CCK-8 assay and flow cytometry. The results indicate that U251 human glioma cells were killed by focused ultrasound (FUS) combined with GA/PLGA microbubbles. FUS combined with GA/PLGA microbubbles was capable of locally and transiently enhancing the permeability of BBB under certain conditions. This conformational change allows the release of GA to extracellular space. This study provides novel targets for the treatment of glioma.