Haojun Ma

T7 peptide-functionalized nanoparticles utilizing RNA interference for glioma dual targeting

Among all the malignant brain tumors, glioma is the deadliest and most common form with poor prognosis. Gene therapy is regarded as a promising way to halt the progress of the disease or even cure the tumor and RNA interference (RNAi) stands out. However, the existence of the blood-brain barrier (BBB) and blood tumor barrier (BTB) limits the delivery of these therapeutic genes. In this work, the delivery system targeting to the transferrin (Tf) receptor highly expressed on both BBB and glioma was successfully synthesized and would not compete with endogenous Tf. U87 cells stably express luciferase were employed here to simulate tumor and the RNAi experiments in vitro and in vivo validated that the gene silencing activity was 2.17-fold higher with the targeting ligand modification. The dual-targeting gene delivery system exhibits a series of advantages, such as high efficiency, low toxicity, stability and high transaction efficiency, which may provide new opportunities in RNAi therapeutics and nanomedicine of brain tumors.

Choline transporter-targeting and co-delivery system for glioma therapy.

Combination of gene therapy and chemotherapy is a promising approach for glioma therapy. In this study, a co-delivery system of plasmid encoding human tumor necrosis factor-related apoptosis-inducing ligand (pORF-hTRAIL, Trail) and doxorubicin (DOX) has been simply constructed in two steps. Firstly, DOX was intercalated into Trail to form a stable complex. Secondly, DOX-Trail complex was condensed by Dendrigraft poly-L-lysine (DGL) to form a nanoscaled co-delivery system. Choline transporters are both expressed on blood-brain barrier (BBB) and glioma, Herein, a choline derivate with high choline transporter affinity was chosen as BBB and glioma dual targeting ligand. Choline-derivate modified co-delivery system showed higher cellular uptake efficiency and cytotoxicity than unmodified co-delivery system in U87 MG cells. In comparison with single medication or unmodified delivery system, Choline-derivate modified co-delivery system induced more apoptosis both in vitro and in vivo. The therapeutic efficacy on U87 MG bearing xenografts further confirmed the predominance of this dual targeting and co-delivery system.

Brain-targeted co-delivery of therapeutic gene and peptide by multifunctional nanoparticles in Alzheimer's disease mice

Multifunctional nanocarriers are increasingly promising for disease treatment aimed to regulate multiple pathological dysfunctions and overcome barriers in drug delivery. Here we develop a multifunctional nanocarrier for Alzheimers disease (AD) treatment by achieving therapeutic gene and peptide co-delivery to brain based on PEGylated dendrigraft poly-l-lysines (DGLs) via systemic administration. The dendritic amine-rich structure of DGLs provides plenty reaction sites and positive charge for drug loading. Successful co-delivery of drugs overcoming the blood-brain barrier by brain-targeted ligand modification was demonstrated both in vitro and in vivo. The pharmacodynamics study of the system following multiple-dosing treatment was verified in transgenic AD mice. Down-regulation of the key enzyme in amyloid-β formation was achieved by delivering non-coding RNA plasmid. Simultaneous delivery of the therapeutic peptide into brain leads to reduction of neurofibrillary tangles. Meanwhile, memory loss rescue in AD mice was also observed. Taken together, the multifunctional nanocarrier provides an excellent drug co-delivery platform for brain diseases.

pH-controlled delivery of nanoparticles into tumor cells.

Nanoparticles target tumor cells by pH-controlled means. Nanoparticles carry three synergistic delivery functions: 1) tumor tissue targeting by the EPR effect; 2) tumor cell targeting by pHLIP-mediated membrane-localization; and 3) tumor cell uptake by adsorptive-mediated endocytosis.

Targeting Caspase-3 as Dual Therapeutic Benefits by RNAi Facilitating Brain-Targeted Nanoparticles in a Rat Model of Parkinson’s Disease

The activation of caspase-3 is an important hallmark in Parkinson’s disease. It could induce neuron death by apoptosis and microglia activation by inflammation. As a result, inhibition the activation of caspase-3 would exert synergistic dual effect in brain in order to prevent the progress of Parkinson’s disease. Silencing caspase-3 genes by RNA interference could inhibit the activation of caspase-3. We developed a brain-targeted gene delivery system based on non-viral gene vector, dendrigraft poly-L-lysines. A rabies virus glycoprotein peptide with 29 amino-acid linked to dendrigraft poly-L-lysines could render gene vectors the ability to get across the blood brain barrier by specific receptor mediated transcytosis. The resultant brain-targeted vector was complexed with caspase-3 short hairpin RNA coding plasmid DNA, yielding nanoparticles. In vivo imaging analysis indicated the targeted nanoparticles could accumulate in brain more efficiently than non-targeted ones. A multiple dosing regimen by weekly intravenous administration of the nanoparticles could reduce activated casapse-3 levels, significantly improve locomotor activity and rescue dopaminergic neuronal loss and in Parkinson’s disease rats’ brain. These results indicated the rabies virus glycoprotein peptide modified brain-targeted nanoparticles were promising gene delivery system for RNA interference to achieve anti-apoptotic and anti-inflammation synergistic therapeutic effects by down-regulation the expression and activation of caspase-3.

Choline Derivate-Modified Doxorubicin Loaded Micelle for Glioma Therapy

Ligand-mediated polymeric micelles have enormous potential for improving the efficacy of glioma therapy. Linear-dendritic drug-polymer conjugates composed of doxorubicin (DOX) and polyethylene glycol (PEG) were synthesized with or without modification of choline derivate (CD). The resulting MeO-PEG-DOX8 and CD-PEG-DOX8 could self-assemble into polymeric micelles with a nanosized diameter around 30 nm and a high drug loading content up to 40.6 and 32.3%, respectively. The optimized formulation 20% CD-PEG-DOX8 micelles had superior cellular uptake and antitumor activity against MeO-PEG-DOX8 micelles. The subcellular distribution using confocal study revealed that 20% CD-PEG-DOX8 micelles preferentially accumulated in the mitochondria. Pharmacokinetic study showed area under the plasma concentration-time curve (AUC0-t) and Cmax for 20% CD-PEG-DOX8 micelles and DOX solution were 1336.58 ± 179.43 mg/L·h, 96.35 ± 3.32 mg/L and 1.40 ± 0.19 mg/L·h, 1.15 ± 0.25 mg/L, respectively. Biodistribution study showed the DOX concentration of 20% CD-PEG-DOX8 micelles treated group at 48 h was 2.37-fold higher than that of MeO-PEG-DOX8 micelles treated group at 48 h and was 24 fold-higher than that of DOX solution treated group at 24 h. CD-PEG-DOX8 micelles (20%) were well tolerated with reduced cardiotoxicity, as evaluated in the body weight change and HE staining studies, while they induced most significant antitumor activity with longest media survival time in an orthotopic mouse model of U87-luci glioblastoma model as displayed in the bioluminescence imaging and survival curve studies. Our findings consequently indicated that 20% CD-PEG-DOX8 micelles are promising drug delivery system for glioma chemotherapy.

Acid active receptor-specific peptide ligand for in vivo tumor-targeted delivery.

Targeting therapy of tumors in their early stages is crucial to increase the survival rate of cancer patients. Currently most drug-delivery systems target the neoplasia through the tumor-associated receptors overexpressed on the cancer cell membrane. However, the expression of these receptors on normal cells and tissues is inevitable, which leads to unwanted accumulation and side effects. Characteristics of the tumor microenvironment, such as acidosis, are pervasive in almost all solid tumors and can be easily accessed. It is shown that the different extracellular pH value can be used to activate/inactivate the receptor-mediated endocytosis on tumor/normal cells. This idea is implemented by conjugating a shielding molecule at the terminus of a receptor-specific ligand via a pH-sensitive hydrazone bond. The acid-activated detachment of the shielding molecule and enhanced tumor/background accumulation ratio are demonstrated. These results suggest that acid active receptor-specific peptide ligand-modified tumor-targeting delivery systems have potential use in the treatment of tumors.

Targeted imaging of activated caspase-3 in the central nervous system by a dual functional nano-device

The activation of caspase-3 mediated neuron death is a common process in neurodegenerative diseases. Efficient activated caspase-3 imaging in brain would be helpful to monitor the potential lesion and intervene promptly. However, the blood-brain barrier (BBB) is the major obstacle that hinders the delivery of diagnostic agents into the brain. Herein, the fluorescence resonance energy transfer (FRET) was successfully applied to detect in vivo activated caspase-3 in apoptotic neuron with a brain-targeted nano-device, which was based on dendrigraft poly-L-lysines (DGLs) and linked with a brain-targeted peptide RVG29 as well as the caspase-3 cleavable peptide linker (DEVD). This nano-device could detect the level of caspase-3 activation in accordance with the degree of apoptosis in rat brain; meanwhile normal rat showed no fluorescence signal. The location of fluorescence signal was confirmed to accumulate more in caspase-3 activated neurons. Taken together, our nano-device would help to image activated caspase-3 in vivo and hold great promise in early diagnosis of neurodegenerative diseases.

Linear-dendritic copolymer composed of polyethylene glycol and all-trans-retinoic acid as drug delivery platform for paclitaxel against breast cancer.

A new linear-dendritic copolymer composed of poly(ethylene glycol) (PEG) and all-trans-retinoic acid (ATRA) was synthesized as the anticancer drug delivery platform (PEG-G3-RA8). It can self-assemble into core-shell micelles with a low critical micelle concentration (CMC) at 3.48 mg/L. Paclitaxel (PTX) was encapsulated into PEG-G3-RA8 to form PEG-G3-RA8/PTX micelles for breast cancer treatment. The optimized formulation had high drug loading efficacy (20% w/w of drug copolymer ratio), nanosized diameter (27.6 nm), and narrow distribution (PDI = 0.103). Compared with Taxol, PEG-G3-RA8/PTX remained highly stable in the serum-containing cell medium and exhibited 4-fold higher cellular uptake. Besides, near-infrared fluorescence (NIR) optical imaging results indicated that fluorescent probe loaded micelle had a preferential accumulation in breast tumors. Pharmacokinetics and biodistribution studies (10 mg/kg) showed the area under the plasma concentration-time curve (AUC0-∞) and mean residence time (MRT0-∞) for PEG-G3-RA8/PTX and Taxol were 12.006 ± 0.605 mg/L h, 2.264 ± 0.041 h and 15.966 ± 1.614 mg/L h, 1.726 ± 0.097 h, respectively. The tumor accumulation of PEG-G3-RA8/PTX group was 1.89-fold higher than that of Taxol group 24 h postinjection. With the advantages like efficient cellular uptake and preferential tumor accumulation, PEG-G3-RA8/PTX showed superior therapeutic efficacy on MCF-7 tumor bearing mice compared to Taxol.

A choline derivate-modified nanoprobe for glioma diagnosis using MRI

Gadolinium (Gd) chelate contrast-enhanced magnetic resonance imaging (MRI) is a preferred method of glioma detection and preoperative localisation because it offers high spatial resolution and non-invasive deep tissue penetration. Gd-based contrast agents, such as Gd-diethyltriaminepentaacetic acid (DTPA-Gd, Magnevist), are widely used clinically for tumor diagnosis. However, the Gd-based MRI approach is limited for patients with glioma who have an uncompromised blood-brain barrier (BBB). Moreover, the rapid renal clearance and non-specificity of such contrast agents further hinders their prevalence. We present a choline derivate (CD)-modified nanoprobe with BBB permeability, glioma specificity and a long blood half-life. Specific accumulation of the nanoprobe in gliomas and subsequent MRI contrast enhancement are demonstrated in vitro in U87 MG cells and in vivo in a xenograft nude model. BBB and glioma dual targeting by this nanoprobe may facilitate precise detection of gliomas with an uncompromised BBB and may offer better preoperative and intraoperative tumor localization.