Jiantao Chen

Tumor microenvironment sensitive doxorubicin delivery and release to glioma using angiopep-2 decorated gold nanoparticles

Glioma is still hard to be treated due to their complex microenvironment. In this study, a gold nanoparticle-based delivery system was developed. The system, An-PEG-DOX-AuNPs, was loaded with doxorubicin (DOX) through hydrazone, an acid-responsive linker, and was functionalized with angiopep-2, a specific ligand of low density lipoprotein receptor-related protein-1 (LRP1), which could mediate the system to penetrate blood brain barrier and target to glioma cells. The particle size of An-PEG-DOX-AuNPs was 39.9 nm with a zeta potential of -19.3 mV, while the DOX loading capacity was 9.7%. In vitro, the release of DOX from DOX-AuNPs was pH-dependent. At lower pH values, especially 5.0 and 6.0, release of DOX was much quicker than that at pH 6.8 and 7.4. After coating with PEG, the acid-responsive release of DOX from PEG-DOX-AuNPs was almost the same as that from DOX-AuNPs. Cellular uptake study showed obviously higher intensity of intracellular An-PEG-DOX-AuNPs compared with PEG-DOX-AuNPs. In vivo, An-PEG-DOX-AuNPs could distribute into glioma at a higher intensity than that of PEG-DOX-AuNPs and free DOX. Correspondingly, glioma-bearing mice treated with An-PEG-DOX-AuNPs displayed the longest median survival time, which was 2.89-fold longer than that of saline. In conclusion, An-PEG-DOX-AuNPs could specifically deliver and release DOX in glioma and significantly expand the median survival time of glioma-bearing mice.

A Novel Strategy through Combining iRGD Peptide with Tumor-Microenvironment-Responsive and Multistage Nanoparticles for Deep Tumor Penetration

Despite the great achievements that nanomedicines have obtained so far, deep penetration of nanomedicines into tumors is still a major challenge in tumor treatment. The enhanced permeability and retention (EPR) effect was the main theoretical foundation for using nanomedicines to treat solid tumor. However, the antitumor efficiency is modest because the tumor is heterogeneous, with dense collagen matrix, abnormal tumor vasculature, and lymphatic system. Nanomedicines could only passively accumulate near leaky site of tumor vessels, and they cannot reach the deep region of tumor. To enhance further the tumor penetration efficiency, we developed a novel strategy of coadministering cell-homing penetration peptide iRGD with size-shrinkable and tumor-microenvironment-responsive multistage system (DOX-AuNPs-GNPs) to overcome these barriers. First, iRGD could specifically increase the permeability of tumor vascular and tumor tissue, leading to more DOX-AuNPs-GNPs leaking out from tumor vasculature. Second, the multistage system passively accumulated in tumor tissue and shrank from 131.1 to 46.6 nm to reach the deep region of tumor. In vitro, coadministering iRGD with DOX-AuNPs-GNPs showed higher cellular uptake and apoptosis ratio. In vivo, coadministering iRGD with DOX-AuNPs-GNPs presented higher penetration and accumulation in tumor than giving DOX-AuNPs-GNPs alone, leading to the best antitumor efficiency in 4T1 tumor-bearing mouse model.

Synergistic Dual-Ligand Doxorubicin Liposomes Improve Targeting and Therapeutic Efficacy of Brain Glioma in Animals

Therapeutic outcome for the treatment of glioma was often limited due to low permeability of delivery systems across the blood-brain barrier (BBB) and poor penetration into the tumor tissue. In order to overcome these hurdles, we developed the dual-targeting doxorubicin liposomes conjugated with cell-penetrating peptide (TAT) and transferrin (T7) (DOX-T7-TAT-LIP) for transporting drugs across the BBB, then targeting brain glioma, and penetrating into the tumor. The dual-targeting effects were evaluated by both in vitro and in vivo experiments. In vitro cellular uptake and three-dimensional tumor spheroid penetration studies demonstrated that the system could not only target endothelial and tumor monolayer cells but also penetrate tumor to reach the core of the tumor spheroids and inhibit the growth of the tumor spheroids. In vivo imaging further demonstrated that T7-TAT-LIP provided the highest tumor distribution. The median survival time of tumor-bearing mice after administering DOX-T7-TAT-LIP was significantly longer than those of the single-ligand doxorubicin liposomes and free doxorubicin. In conclusion, the dual-ligand liposomes comodified with T7 and TAT possessed strong capability of synergistic targeted delivery of payload into tumor cells both in vitro and in vivo, and they were able to improve the therapeutic efficacy of brain glioma in animals.

High Tumor Penetration of Paclitaxel Loaded pH Sensitive Cleavable Liposomes by Depletion of Tumor Collagen I in Breast Cancer.

The network of collagen I in tumors could prevent the penetration of drugs loaded in nanoparticles, and this would lead to impaired antitumor efficacy. In this study, free losartan (an angiotensin inhibitor) was injected before treatment to reduce the level of collagen I, which could facilitate the penetration of nanoparticles. Then the pH-sensitive cleavable liposomes (Cl-Lip) were injected subsequently to exert the antitumor effect. The Cl-Lip was constituted by PEG(5K)-Hydrazone-PE and DSPE-PEG(2K)-R8. When the Cl-Lip reached to the tumor site by the enhanced permeability and retention (EPR) effect, PEG(5K)-Hydrazone-PE was hydrolyzed from the Cl-Lip under the low extra-cellular pH conditions of tumors, then the R8 peptide was exposed, and finally liposomes could be internalized into tumor cells by the mediation of R8 peptide. In vitro experiments showed both the cellular uptake of Cl-Lip by 4T1 cells and cytotoxicity of paclitaxel loaded Cl-Lip (PTX-Cl-Lip) were pH sensitive. In vivo experiments showed the Cl-Lip had a good tumor targeting ability. After depletion of collagen I, Cl-Lip could penetrate into the deep place of tumors, the tumor accumulation of Cl-Lip was further increased by 22.0%, and the oxygen distributed in tumor tissues was also enhanced. The antitumor study indicated free losartan in combination with PTX-Cl-Lip (59.8%) was more effective than injection with PTX-Cl-Lip only (37.8%) in 4T1 tumor bearing mice. All results suggested that depletion of collagen I by losartan dramatically increased the penetration of PTX-Cl-Lip and combination of free losartan and PTX-CL-Lip could lead to better antitumor efficacy of chemical drugs. Thus, the combination strategy might be a promising tactic for better treatment of solid tumors with a high level of collagen I.

Enhanced Glioma Targeting and Penetration by Dual-Targeting Liposome Co-modified with T7 and TAT

The development of a drug delivery strategy that can not only cross the blood-brain barrier (BBB) rapidly, but also target the glioma and reach the core of glioma is essential and important for glioma treatment. To achieve this goal, we established a dual-targeting liposomal system modified with TAT (AYGRKKRRQRRR) and T7 (HAIYPRH), in which the specific ligand T7 could target BBB and brain glioma tumor and the nonspecific ligand TAT could enhance the effect of passing through BBB, and elevate the penetration into the tumor. The dual-targeting effects were evaluated by both in vitro and in vivo experiments. To identify the targeting effect, in vitro cellular uptake and BBB model were performed. Tumor spheroid penetration was performed to evaluate the penetration characteristics of the dual-targeting liposomes. In vivo pharmacokinetic studies were utilized to evaluate the influence of T7 and TAT peptides on the behavior of nanoparticle drug delivery system, and tissue distribution was further utilized to evaluate the glioma-targeting efficiency of the dual-targeting liposomes.

A simple one-step method for preparation of fluorescent carbon nanospheres and the potential application in cell organelles imaging

Highly fluorescent carbon nanospheres with a quantum yield of 17.6% have been prepared by a one-step method with hydrothermal treatment of spider silk. Due to the high photostability, low toxicity and well blood compatibility, these carbon nanospheres could be used as an excellent probes for cancer cell imaging.

PEGylated fluorescent carbon nanoparticles for noninvasive heart imaging.

Fluorescent carbon nanoparticles (CNP) have gained much attention due to their unique fluorescent properties and safety. In this study, we evaluated the potential application of CNP and PEGylated CNP (PEG-CNP) in noninvasive heart imaging. CNP was prepared by hydrothermal treatment of silk. The particle size and zeta potential of CNP were 121.8 nm and -3.7 mV, respectively, which did not change significantly after PEGylation with a PEG density of 4.43 ± 0.02 μg/mg CNP. FTIR and XPS showed that CNP possessed several functional groups, such as -COOH, -OH, and NH2, which could be utilized for PEGylation and other modifications. CNP displayed strong blue fluorescence after excitation at the wavelength of 375 nm. PEG-CNP displayed better serum stability compared to CNP. The hemolysis rate of PEG-CNP was lower than that of CNP, suggesting PEGylation could enhance the hemocompatibility of CNP. Both CNP and PEG-CNP showed higher uptake capacity by H9c2 cells (a heart cell line) than that by human umbilical vein endothelial cells (HUVEC), suggesting the particles tend to be selectively taken up by heart cells. Both CNP and PEG-CNP were proven to be taken up through endosome-mediated pathway, and the colocalization of nanoparticles with mitochondria was also observed. In vivo results demonstrated that CNP could target heart with much higher fluorescent intensity than liver and spleen. Although PEGylation could decrease the distribution in heart, it remained high for PEG-CNP. In conclusion, CNP could be used for heart imaging, and moreover, PEGylation could improve the stability and biocompatibility of CNP.

A dual strategy to improve the penetration and treatment of breast cancer by combining shrinking nanoparticles with collagen depletion by losartan

UNLABELLED Although development of nanomedicines has been a promising direction in tumor treatment, the therapeutic outcome of current nanomedicines is unsatisfying, partly because of the poor retention and penetration in tumors. Recently, a kind of tumor microenvironment sensitive size shrinkable nanoparticles (DOX-AuNPs-GNPs) has been developed by our lab, which could enhance the tumor penetration and retention depending on the size shrinking. However, the further enhancement is still restricted by dense collagen network in tumors. Thus in this study, we combined DOX-AuNPs-GNPs with losartan to deplete tumor collagen (constituted up to 90% of extracellular matrix) to further improve tumor penetration. In vitro, DOX-AuNPs-GNPs can shrink from over 117.8nm to less than 50.0nm and release DOX-AuNPs under the triggering of tumor overexpressed matrix metalloproteinases-2 (MMP-2). In vivo, pretreatment with losartan significantly decrease the collagen level and improve the tumor penetration. In combination, losartan combined with DOX-AuNPs-GNPs showed the best drug delivery efficiency, striking penetration efficiency and best 4T1 breast tumor inhibition effect. In conclusion, this study provided a promising synergetic strategy to improve the tumor treatment efficiency of nanomedicines. STATEMENT OF SIGNIFICANCE We have developed a dual strategy for deep tumor penetration through combining size shrinkable DOX-AuNPs-GNPs with depleting tumor collagen by losartan. Additionally, we demonstrate therapeutic efficacy in breast tumor bearing mouse model. DOX-AuNPs-GNPs co-administration with losartan is a novel and highly attractive strategy for anti-tumor drug delivery with the potential for broad applications in clinic.

Fluorescent Carbonaceous Nanodots for Noninvasive Glioma Imaging after Angiopep-2 Decoration

Fluorescent carbonaceous nanodots (CDs) have attracted much attention due to their unique properties. However, their application in noninvasive imaging of diseased tissues was restricted by the short excitation/emission wavelengths and the low diseased tissue accumulation efficiency. In this study, CDs were prepared from glucose and glutamic acid with a particle size of 4 nm. Obvious emission could be observed at 600 to 700 nm when CDs were excited at around 500 nm. This property enabled CDs with capacity for deep tissue imaging with low background adsorption. Angiopep-2, a ligand which could target glioma cells, was anchored onto CDs after PEGylation. The product, An-PEG-CDs, could target C6 glioma cells with higher intensity than PEGylated CDs (PEG-CDs), and endosomes were involved in the uptake process. In vivo, An-PEG-CDs could accumulate in the glioma site at higher intensity, as the glioma/normal brain ratio for An-PEG-CDs was 1.73. The targeting effect of An-PEG-CDs was further demonstrated by receptor staining, which showed An-PEG-CDs colocalized well with the receptors expressed in glioma. In conclusion, An-PEG-CDs could be successfully used for noninvasive glioma imaging.

Targeting delivery and deep penetration using multistage nanoparticles for triple-negative breast cancer

Targeting delivery and deep penetration have been attracting tremendous attention in triple-negative breast cancer (TNBC) theranostics. Herein, we reported a novel multistage system (G-AuNPs-DOX-RRGD) with an active targeting effect and size-changeable property to inhibit tumor growth and metastasis in 4T1 xenograft bearing mice. The system was constructed through fabricating small-size gold nanoparticles (AuNPs) onto matrix metalloproteinase-2 (MMP-2) degradable gelatin nanoparticles (GNPs). Doxorubicin (DOX) was tethered onto AuNPs via a pH sensitive hydrazone bond, and RRGD, a tandem peptide of RGD and octarginine, was surface-decorated onto the system to improve its tumor targeting efficiency. In vitro, the G-AuNPs-DOX-RRGD could shrink from 185.9 nm to 71.2 nm after 24 h incubation with MMP-2 and the DOX was released in a pH-dependent manner. Tumor spheroid penetration and collagen diffusion demonstrated G-AuNPs-DOX-RRGD possessed best penetrating efficiency. In vivo, the G-AuNPs-DOX-RRGD actively targeted to the 4T1 tumor and then penetrated through the interstitial matrix, resulted in enhanced accumulation in the deep tumor region. Therefore, the G-AuNPs-DOX-RRGD could approach excellent anti-tumor capacity owing to the synergistic effect of RRGD and the size-changeable property.