Furthermore, we demonstrate that miR-30b/c and miR-21 target respectively the 3' untranslated region of caspase-3 and TAp63 mRNAs, and that those proteins mediate some of the effects of miR-30 and -21 on TRAIL resistance, even in human glioblastoma primary cells and in lung cancer cells.
Here, we investigate the role of heterogeneous nuclear ribonucleoprotein C1/C2 (hnRNPC) in the metastatic potential of the glioblastoma cell line T98G. hnRNPC bound directly to primary miR-21 (pri-miR-21) and promoted miR-21 expression in T98G cells.
The levels of miR-10b and miR-21 are found significantly increased in the CSF of patients with glioblastoma and brain metastasis of breast and lung cancer, compared with tumors in remission and a variety of nonneoplastic conditions.
Accumulating evidence indicated that downregulation of miR-21 in glioblastoma cells caused repression of growth and increased apoptosis, all of which could theoretically enhance the chemotherapeutic effects of cancer therapy.
These critical in vivo findings demonstrate an important functional linkage between mir-21 and Pdcd4 and further elucidate the molecular mechanisms by which the known high level of mir-21 expression in glioblastoma can attribute to tumorigenesis--namely, inhibition of Pdcd4 and its tumor-suppressive functions.
Taken together, these findings suggest that miR-21 inhibitor can increase IR-induced growth arrest and apoptosis in U251 glioblastoma cells, at least in part by abrogating G(2)-M arrest, and that Cdc25A is a potential target of miR-21.
MiR-195, miR-196b, miR-181c, miR-21 expression levels and O-6-methylguanine-DNA methyltransferase methylation status are associated with clinical outcome in glioblastoma patients.
Inhibition of two glioblastoma-upregulated miRNAs (miR-21 and miR-23a) and exogenous overexpression of two glioblastoma-downregulated miRNAs (miR-218 and miR-219-5p) resulted in reduced soft agar colony formation but showed varying effects on cell proliferation and chemosensitivity.
Human glioblastoma U251 (PTEN-mutant) and LN229 (PTEN wild-type) cells were treated with taxol and the miR-21 inhibitor (in a poly (amidoamine) (PAMAM) dendrimer), alone or in combination.
Our findings suggest that miR-21 represents a promising target for therapeutic manipulation to increase the efficacy of chemotherapeutic agents in treating glioblastoma, a highly lethal type of cancer.
These findings establish miR-21 as an important oncogene that targets a network of p53, TGF-beta, and mitochondrial apoptosis tumor suppressor genes in glioblastoma cells.
Expression of PDCD4 protein correlates inversely with expression of miR-21 in a number of human glioblastoma cell lines such as T98G, A172, U87, and U251.