Glioblastoma cells secrete extra-cellular vesicles (EVs) containing microRNAs (miRNAs). Analysis of these EV miRNAs in the bio-fluids of afflicted patients represents a potential platform for biomarker development. However, the analytic algorithm for quantitative assessment of EV miRNA remains under-developed. Here, we demonstrate that the reference transcripts commonly used for quantitative PCR (including GAPDH, 18S rRNA, and hsa-miR-103) were unreliable for assessing EV miRNA. In this context, we quantitated EV miRNA in absolute terms and normalized this value to the input EV number. Using this method, we examined the abundance of miR-21, a highly over-expressed miRNA in glioblastomas, in EVs. In a panel of glioblastoma cell lines, the cellular levels of miR-21 correlated with EV miR-21 levels (p<0.05), suggesting that glioblastoma cells actively secrete EVs containing miR-21. Consistent with this hypothesis, the CSF EV miR-21 levels of glioblastoma patients (n=13) were, on average, ten-fold higher than levels in EVs isolated from the CSF of non-oncologic patients (n=13, p<0.001). Notably, none of the glioblastoma CSF harbored EV miR-21 level below 0.25 copies per EV in this cohort. Using this cut-off value, we were able to prospectively distinguish CSF derived from glioblastoma and non-oncologic patients in an independent cohort of twenty-nine patients (Sensitivity=87%; Specificity=93%; AUC=0.91, p<0.01). Our results suggest that CSF EV miRNA analysis of miR-21 may serve as a platform for glioblastoma biomarker development.

Protein corona presents a major obstacle to bench-to-bedside translation of targeted drug delivery systems, severely affecting targeting yields and directing unfavorable biodistribution. Corona-mediated targeting provides a new impetus for specific drug delivery by precisely manipulating interaction modes of functional plasma proteins on nano-surface. Here bio-inspired liposomes (SP-sLip) were developed by modifying liposomal surface with a short nontoxic peptide derived from Aβ 1-42 that specifically interacts with the lipid-binding domain of exchangeable apolipoproteins. SP-sLip absorb plasma apolipoproteins A1, E and J, consequently exposing receptor-binding domain of apolipoproteins to achieve brain-targeted delivery. Doxorubicin loaded SP-sLip (SP-sLip/DOX) show significant enhancement of brain distribution and anti-brain cancer effect in comparison to doxorubicin loaded plain liposomes. SP-sLip preserve functions of the absorbed human plasma ApoE, and the corona-mediated targeting strategy works in SP modified PLGA nanoparticles. The present study may pave a new avenue to facilitate clinical translation of targeted drug delivery systems.

Purpose The objective of this study was to evaluate clinical significance and immunosuppressive mechanisms of B7-H4 (B7x/B7S1), a B7 family member, in glioma. Experimental Design B7-H4 levels in glioma tissue/cerebral spinal fluid (CSF) were compared between different grades of glioma patients. Survival data were analyzed with Kaplan–Meier to determine prognostic value of B7-H4. Cytokines from CD133+ cells to stimulate the expression of B7-H4 on human Mφs were investigated by FACS, neutralizing antibodies and transwell chemotaxis assay. shRNA, reporter vector and ChIP were used to determine the binding of STAT3 to the B7-H4 promoter. The function of B7-H4+ Mφs in vitro was evaluated through phagocytosis, T cell proliferation/apoptosis and cytokine production as well as in xenografted model for in vivo analysis. Results We found that B7-H4 expression in tumors was associated with prognosis of human glioblastoma and correlated directly with malignant grades. Mechanistically, glioma initiating CD133+ cells and macrophages/microglia co-interaction activated expression of B7-H4 via IL-6 and IL-10 in both tumor cells and microenvironment supporting cells. IL-6-activated STAT3 bound to the promoter of B7-H4 gene and enhanced B7-H4 expression. Furthermore, CD133+ cells mediated immunosuppression through B7-H4 expression on macrophages/microglia by silencing of B7-H4 expression on these cells which led to increased microenvironment T cell function and tumor regression in the xenograft glioma mouse model. Conclusion We have identified B7-H4 activation on macrophages/microglia in the microenvironment of gliomas as an important immunosuppressive event blocking effective T-cell immune responses.