miR-331-3p regulates expression of neuropilin-2 in glioblastoma. J Neurooncol. 2014;116:67-75. [PMID: 24142150 PMCID: PMC3889298 DOI: 10.1007/s11060-013-1271-7]

Expression of microRNA-331 can be used as a predictor for response to therapy and survival in acute myeloid leukemia patients

AIM

Aberrant expression of microRNAs (miRs) has been proved to have a role in acute myeloid leukemias (AML), but there is no information on miR-331 in AML.

MATERIALS & METHODS

miR-331 expression has been analyzed using reverse-transcription polymerase chain reaction (RT-PCR) in 95 bone marrow specimens from newly diagnosed AML patients in comparison with 20 healthy subjects.

RESULTS

miR-331 was upregulated in AML patients and its expression seemed to influence remission achieving and death risk. The time of remission duration in patients with complete remission was longer in subjects with miR-331 downregulation after induction chemotherapy.

CONCLUSION

we showed for the first time that miR-331 higher expression appears to be correlated with worse response to therapy and shorter survival of AML patients.

MicroRNA-331-3p promotes proliferation and metastasis of hepatocellular carcinoma by targeting PH domain and leucine-rich repeat protein phosphatase

Hepatocellular carcinoma (HCC) is a highly invasive tumor with frequent intrahepatic or pulmonary metastasis, which is the main reason for high recurrence and poor survival of HCC after liver resection. However, the mechanisms for metastasis remain incompletely clear. Given that microRNAs (miRNAs) are implicated in HCC progression, we explored a potential role of miRNAs in metastasis by performing miRNA expression profiling in three subtypes of HCC with different metastatic potentials. We discovered miR-331-3p as one of most significantly overexpressed miRNAs and highly associated with metastasis of HCC. Increased expression of miR-331-3p was correlated with poor long-term survival of HCC. We provided both in vivo and in vitro evidence demonstrating that miR-331-3p promoted proliferation and metastasis of HCC cells. Using an integrated approach, we uncovered that PH domain and leucine-rich repeat protein phosphatase (PHLPP) was a novel target of miR-331-3p. Indeed, the miR-331-3p-mediated effects were antagonized by reexpression of PHLPP or mimicked by silencing of PHLPP. We further showed that miR-331-3p-mediated inhibition of PHLPP resulted in stimulation of protein kinase B (AKT) and subsequent epithelial mesenchymal transition (EMT). Finally, inhibition of miR-331-3p through a jetPEI-mediated delivery of anti-miR-331-3p vector resulted in marked inhibition of proliferation and metastasis of HCC in xenograft mice.

CONCLUSION

miR-331-3p promotes proliferation and EMT-mediated metastasis of HCC through suppression of PHLPP-mediated dephosphorylation of AKT. Our work implicates miR-331-3p as a potential prognostic biomarker and a novel therapeutic target.

Heparan sulfate signaling in cancer

Heparan sulfate (HS) is a biopolymer consisting of variably sulfated repeating disaccharide units. The anticoagulant heparin is a highly sulfated intracellular variant of HS. HS has demonstrated roles in embryonic development, homeostasis, and human disease via non-covalent interactions with numerous cellular proteins, including growth factors and their receptors. HS can function as a co-receptor by enhancing receptor-complex formation. In other contexts, HS disrupts signaling complexes or serves as a ligand sink. The effects of HS on growth factor signaling are tightly regulated by the actions of sulfyltransferases, sulfatases, and heparanases. HS has important emerging roles in oncogenesis, and heparin derivatives represent potential therapeutic strategies for human cancers. Here we review recent insights into HS signaling in tumor proliferation, angiogenesis, metastasis, and differentiation. A cancer-specific understanding of HS signaling could uncover potential therapeutic targets in this highly actionable signaling network.