Therapeutic potential of targeting microRNA-10b in established intracranial glioblastoma: first steps toward the clinic

A combined microRNA-based targeted therapeutic approach to eradicate glioblastoma stem-like cells

A minor population of glioblastoma stem-like cells (GSCs) has been implicated in the relapse and resistance of glioblastoma to therapeutic treatments. Based on knowledge of the involvement of multiple microRNAs in GSC propagation, we designed a combinational approach to target the GSC population with multiple miRNA-based therapeutics. As carriers for the targeted delivery we took advantage of two aptamers that bind to, and inhibit, the receptor tyrosine kinases, Axl and PDGFRβ. We showed that the aptamer conjugates are transported through an in vitro blood-brain barrier (BBB) model. Furthermore, combining miR-137 and antimiR-10b synergizes with the receptor inhibitory function of aptamer carriers and prevents GSC expansion. Results highlighted the potential of combining multifunctional RNA-based therapeutics for selective targeting of GSCs and offer a proof of principle strategy to potentially fulfill the still unmet need for effective and safe treatment of glioma.

MiR-422a acts as a tumor suppressor in glioblastoma by targeting PIK3CA

Although surgical treatment, chemotherapy, and radiotherapy have improved the overall survival rate in glioblastoma multiforme (GBM), further intensive research of GBM's molecular mechanism is still needed. In this study, we observed that miR-422a was downregulated in GBM tissues and cell lines by quantitative real-time polymerase chain reaction (PCR) and primer extension assay. Overexpression of miR-422a significantly reduced the cell proliferation, migration, and invasion of GBM cells. Functional study indicated that miR-422a inhibited cell proliferation, invasion, and migration by targeting PIK3CA, an important member of PI3K/Akt signal pathway. These results demonstrate that the miR-422a/PIK3CA axis may constitute a potential target for GBM therapy.

MiR-10b decreases sensitivity of glioblastoma cells to radiation by targeting AKT

Background

Glioblastomas are the most aggressive brain tumors with extremely poor prognosis despite advances in treatment techniques. MiR-10b is highly expressed in glioblastoma and regulates cell proliferation, migration and invasion. Here, we examined the role of MiR-10b on radiotherapy of glioblastomas.

Methods

MiR-10b mimic or anti-MiR-10b inhibitor was transfected in glioblastoma cells. WST-1 assay was used to examine the effect of MiR-10b on proliferation of transfected glioblastoma cells after radiation treatment. Apoptosis was examined by caspase 3/7 activity and TUNEL assay. The western blot was used to evaluate protein expression.

Results

Altered expression of MiR-10b changed the radiation-induced inhibitory effect on proliferation of glioblastoma cells with dose-dependent manner. MiR-10b decreased radiation-induced apoptosis in glioblastoma cells by activation of caspase 3/7 and inhibition Bcl-2 expression. MiR-10b enhances migration and invasion of glioblastoma cells in presence of radiation. In addition, MiR-10b decreased the sensitivity of glioblastoma cells to radiotherapy by activation of p-AKT expression.

Conclusions

MiR-10b might be a potential biomarker to predict radiotherapy response and prognosis in glioblastomas.