Afterglow/Photothermal Bifunctional Polymeric Nanoparticles for Precise Postbreast-Conserving Surgery Adjuvant Therapy and Early Recurrence Theranostic.

Adjuvant whole-breast radiotherapy is essential for breast cancer patients who adopted breast-conserving surgery (BCS) to reduce the risk of local recurrences, which however suffer from large-area and highly destructive ionizing radiation-induced adverse events. To tackle this issue, an afterglow/photothermal bifunctional polymeric nanoparticle (APPN) is developed that utilizes nonionizing light for precise afterglow imaging-guided post-BCS adjuvant second near-infrared (NIR-II) photothermal therapy. APPN consists of a tumor cell targeting afterglow agent, which is doped with a NIR dye as an afterglow initiator and a NIR-II light-absorbing semiconducting polymer as a photothermal transducer. Such a design realizes precise afterglow imaging-guided NIR-II photothermal ablation of minimal residual breast tumor foci after BCS, thus achieving complete inhibition of local recurrences. Moreover, APPN enables early diagnosis and treatment of local recurrence after BCS. This study thus provides a nonionizing modality for precision post-BCS adjuvant therapy and early recurrence theranostic.

Iodine-Rich Semiconducting Polymer Nanoparticles for CT/Fluorescence Dual-Modal Imaging-Guided Enhanced Photodynamic Therapy.

Photodynamic therapy (PDT) is a promising technique for cancer therapy, providing good therapeutic efficacy with minimized side effect. However, the lack of oxygen supply in the hypoxic tumor site obviously restricts the generation of singlet oxygen (1 O2 ), thus limiting the efficacy of PDT. So far, the strategies to improve PDT efficacy usually rely on complicated nanosystems, which require sophisticated design or complex synthetic procedure. Herein, iodine-rich semiconducting polymer nanoparticles (SPN-I) for enhanced PDT, using iodine-induced intermolecular heavy-atom effect to elevate the 1 O2 generation, are designed and prepared. The nanoparticles are composed of a near-infrared (NIR) absorbing semiconducting polymer (PCPDTBT) serving as the photosensitizer and source of fluorescence signal, and an iodine-grafted amphiphilic diblock copolymer (PEG-PHEMA-I) serving as the 1 O2 generation enhancer and nanocarrier. Compared with SPN composed of PEG-b-PPG-b-PEG and PCPDTBT (SPN-P), SPN-I can enhance the 1 O2 generation by 1.5-fold. In addition, SPN-I have high X-ray attenuation coefficient because of the high density of iodine in PEG-PHEMA-I, providing SPN-I the ability of use with computed tomography (CT) and fluorescence dual-modal imaging. The study thus provides a simple nanotheranostic platform composed of two components for efficient CT/fluorescence dual-modal imaging-guided enhanced PDT.

Strengthening Gastric Cancer Therapy by Trastuzumab-Conjugated Nanoparticles with Simultaneous Encapsulation of Anti-MiR-21 and 5-Fluorouridine.

BACKGROUND/AIMS: MicroRNA-21 is an oncogenic miR (oncomiR) frequently elevated in gastric cancer (GC). Overexpression of miR-21 decreases the sensitivity of GC cells to 5-fluorouridine (5-Fu) and trastuzumab, a humanized monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2). Receptor-mediated endocytosis plays a crucial role in the delivery of biotherapeutics including anti-miRNA oligonucleotides (AMOs). This study is a continuation of earlier findings involving poly(ε-caprolactone) (PCL)-poly (ethylene glycol) (PEG) nanoparticles (PEG-PCL NPs), which were coated with trastuzumab to target GC with HER2 receptor over-expression using anti-miRNA-21 (AMO-21) and 5-Fu. METHODS: HER-PEG-PCL NPs were prepared by one-step carbodiimide coupling using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAc) and Sulfo-NHS in aqueous phase. Covalent coupling of amino groups at the surface of PEG-PCL with the carboxyl groups of trastuzumab was analyzed by X-ray photoelectron spectroscopy (XPS). AMO-21/5-Fu NPs were formulated by a double-emulsion solvent evaporation technique. The cell line specificity, cellular uptake and AMO-21 delivery were investigated through the rhodamine-B-labeled 6-carboxyfluorescein (FAM)-AMO-21-PEG-PCL NPs coated with or without the antibody in both Her2-positive (NUGC4) and negative GC cells (SGC7901) visualized by fluorescence microscopy. The cytotoxicity of the HER-PEG-PCL NPs encapsulating AMO-21 was evaluated by MTT and apoptosis. Real-time reverse-transcription polymerase chain reaction (RT-PCR) was used to examine miR-21 and phosphatase and tensin homolog (PTEN) and Sprouty2 expression in GC cell lines. The antitumor effects of AMO-21/5-Fu NPs were compared with other groups in xenograft gastric cancer mice. RESULTS: The antibody conjugates significantly enhanced the cellular uptake of NPs. The AMO-21/5-Fu NPs effectively suppressed the target miRNA expression in GC cells, which further up-regulated PTEN and Sprouty2. As a result, the sensitivity of HER2-expressing gastric cancer to trastuzumab and 5-Fu were enhanced both in vitro and in vivo. The approach enhanced the targeting by trastuzumab as well as antibody-dependent cellular cytotoxicity (ADCC) of immune effector cells Conclusions: Taken together, the results provide insight into the biological and clinical potential of targeted AMO-21 and 5-Fu co-delivery using modified trastuzumab for GC treatment.

Paclitaxel/tetrandrine coloaded nanoparticles effectively promote the apoptosis of gastric cancer cells based on "oxidation therapy".

Paclitaxel (Ptx) has demonstrated encouraging activity in the treatment of gastric cancer. Development of drug-containing biodegradable polymeric nanoparticles (np) becomes one of the solutions to relieve side effects of Ptx. However, Ptx-loaded nanoparticles prepared by the nanoprecipitation method are unstable in the aqueous phase. Here we report that tetrandrine (Tet) effectively increases the stability of Ptx-loaded nanoparticles when Tet is coencapsulated with Ptx into mPEG-PCL nanoparticles. The current study demonstrates the synergistic antitumor effect of Tet and Ptx against gastric cancer cells, which provides the basis of coadministration of Tet and Ptx by nanoparticles. It is reported that the cellular chemoresistance to Ptx correlates with intracellular antioxidant capacity and the depletion of cellular antioxidant capacity could enhance the cytotoxicity of Ptx. Tet effectively induces intracellular ROS production. Therefore, the present study provides a promising novel therapeutic strategy basing on "oxidation therapy" that it could amplify the antitumor effect of paclitaxel by employing Tet as a pro-oxidant. More intracellular Tet accumulation by endocytosis of Ptx/Tet-np than equivalent doses of free drug leads to more intracellular ROS induction, which could efficiently enhance the cytotoxicity of Ptx by sequential inhibition of ROS-dependent Akt pathway and activation of apoptotic pathways, all of which would mediate the superior cytotoxicity of Ptx/Tet-np over free drug. The present results suggest that the codelivery of Ptx and Tet by nanoparticles provides a novel therapeutic strategy basing on "oxidation therapy" against gastric cancer.

Superior antimetastatic effect of pemetrexed-loaded gelatinase-responsive nanoparticles in a mouse metastasis model.

Novel pemetrexed-loaded gelatinase-responsive nanoparticles were prepared as a targeted delivery system to determine its potential for clinical therapy of malignant melanoma. The pemetrexed-loaded poly(ethylene glycol)(PEG)-peptide-poly(ε-caprolactone) (PCL) nanoparticles included a gelatinase-cleavage peptide and a PEG-PCL-based structure. The pemetrexed-loaded PEG-peptide-PCL nanoparticles have shown the best antimetastatic effect in experimental lung metastasis models. The expressions of CD133 and thymidylate synthetase of metastatic tumors were also evaluated in our studies. Our results showed that pemetrexed-loaded gelatinase-responsive nanoparticles may represent a potent drug delivery system for inhibiting pulmonary metastasis and our preclinical results can provide new avenues for clinical therapy of malignant melanoma.

iRGD Co-Administration with Paclitaxel-Loaded PLGA Nanoparticles Enhance Targeting and Antitumor Effect in Colorectal Cancer Treatment.

OBJECTIVE: To explore the targeting effect of PLGA-NP and iRGD co-administration with PTXPLGA NP (PTX-PLGA + iRGD) on colorectal cancer. METHODS: Whether PLGA-NP co-administration with iRGD peptide could show effective tumor-targeting ability in contrast to with PLGA-NP in colorectal cancer mice models was evaluated. Moreover, the chemotherapeutics Paclitaxel (PTX) was loaded into the PLGA-NP to impart anti-tumor efficiency to the PTX-PLGA. Whether iRGD co-administration with PTX-PLGA NP (PTX-PLGA + iRGD) in colorectal cancer models enabled PTX to achieve better anti-tumor efficiency and biocompatibility was further assessed. RESULTS: The targeting ability of PLGA-NP was enhanced in cell experiment and colorectal cancer mice models by co-administration of iRGD. As a result, PTX-PLGA + iRGD achieved better anti-tumor efficacy than PTX and PTX-PLGA. Conlusion: The nanocarrier based on PLGA with specific targeting ability could promote the clinical application of various chemotherapeutics similar to PTX. The combination of drug-loaded nanoparticles and iRGD could develop into a promising drug delivery system.

Combined delivery of salinomycin and docetaxel by dual-targeting gelatinase nanoparticles effectively inhibits cervical cancer cells and cancer stem cells.

Intra-tumor heterogeneity is widely accepted as one of the key factors, which hinders cancer patients from achieving full recovery. Especially, cancer stem cells (CSCs) may exhibit self-renewal capacity, which makes it harder for complete elimination of tumor. Therefore, simultaneously inhibiting CSCs and non-CSCs in tumors becomes a promising strategy to obtain sustainable anticancer efficacy. Salinomycin (Sal) was reported to be critical to inhibit CSCs. However, the poor bioavailability and catastrophic side effects brought about limitations to clinical practice. To solve this problem, we previously constructed gelatinase-stimuli nanoparticles composed of nontoxic, biocompatible polyethylene glycol-polycaprolactone (PEG-PCL) copolymer with a gelatinase-cleavable peptide Pro-Val-Gly-Leu-Iso-Gly (PVGLIG) inserted between the two blocks of the copolymer. By applying our "smart" gelatinase-responsive nanoparticles for Sal delivery, we have demonstrated specific accumulation in tumor, anti-CSCs ability and reduced toxicity of Sal-NPs in our previous study. In the present study, we synthesized Sal-Docetaxel-loaded gelatinase-stimuli nanoparticles (Sal-Doc NP) and confirmed single emulsion as the optimal method of producing Sal-Doc NPs (Sal-Doc SE-NP) in comparison with nanoprecipitation. Sal-Doc SE-NPs inhibited both CSCs and non-CSCs in mice transplanted with cervical cancer, and might be associated with enhanced restriction of epithelial-mesenchymal transition (EMT) pathway. Besides, the tumorigenic capacity and growing speed were obviously suppressed in Sal-Doc-SE-NPs-treated group in rechallenge experiment. Our results suggest that Sal-Doc-loaded gelatinase-stimuli nanoparticles could be a promising strategy to enhance antitumor efficacy and reduce side effects by simultaneously suppressing CSCs and non-CSCs.

Antitumor Activity of Thermosensitive Hydrogels Packaging Gambogic Acid Nanoparticles and Tumor-Penetrating Peptide iRGD Against Gastric Cancer.

INTRODUCTION: Gambogic acid (GA) is proved to have anti-tumor effects on gastric cancer. Due to poor solubility, non-specific biological distribution, toxicity to normal tissues and short half-life, it is hard to be applied into the clinic. To overcome these issues, we developed a thermosensitive and injectable hydrogel composed of hydroxypropyl cellulose, silk fibroin and glycerol, with short gelling time, good compatibility and sustained release, and demonstrated that the hydrogel packaged with gambogic acid nanoparticles (GA-NPs) and tumor-penetrating peptide iRGD could improve the anti-tumor activity. METHODS: The Gelling time and micropore size of the hydrogels were regulated through different concentrations of glycerol. Controlled release characteristics of the hydrogels were evaluated with a real-time near-infrared fluorescence imaging system. Location of nanoparticles from different carriers was traced by confocal laser scanning microscopy. The in vivo antitumor activity of the hydrogels packaging GA-NPs and iRGD was evaluated by investigating tumor volume and tumor size. RESULTS: The thermo-sensitive properties of hydrogels were characterized by 3-4 min, 37°C, when glycerol concentration was 20%. The hydrogels physically packaged with GA-NPs and iRGD showed higher fluorescence intensity than other groups. The in vivo study indicated that the co-administration of GA-NPs and iRGD by hydrogels had higher antitumor activity than the GA-loaded hydrogels and free GA combining with iRGD. Free GA group showed few antitumor effects. Compared with the control group, the body weight in other groups had no obvious change, and the count of leukocytes and hemoglobin was slightly decreased. DISCUSSION: The hydrogel constructed iRGD and GA-NPs exerted an effective anti-tumor effect possibly due to retention effect, local administration and continuous sustained release of iRGD promoting the penetration of nanoparticles into a deep part of tumors. The delivery system showed little systemic toxicity and would provide a promising strategy to improve anti-gastric cancer efficacy.

Enhanced and Prolonged Antitumor Effect of Salinomycin-Loaded Gelatinase-Responsive Nanoparticles via Targeted Drug Delivery and Inhibition of Cervical Cancer Stem Cells.

BACKGROUND: Cervical cancer stem cells (CCSCs) represent a subpopulation of tumor cells that possess self-renewal capacity and numerous intrinsic mechanisms of resistance to conventional chemotherapy and radiotherapy. These cells play a crucial role in relapse and metastasis of cervical cancer. Therefore, eradication of CCSCs is the primary objective in cervical cancer therapy. Salinomycin (Sal) is an agent used for the elimination of cancer stem cells (CSCs); however, the occurrence of several side effects hinders its application. Nanoscale drug-delivery systems offer great promise for the diagnosis and treatment of tumors. These systems can be used to reduce the side effects of Sal and improve clinical benefit. METHODS: Sal-loaded polyethylene glycol-peptide-polycaprolactone nanoparticles (Sal NPs) were fabricated under mild and non-toxic conditions. The real-time biodistribution of Sal NPs was investigated through non-invasive near-infrared fluorescent imaging. The efficacy of tumor growth inhibition by Sal NPs was evaluated using tumor xenografts in nude mice. Flow cytometry, immunohistochemistry, and Western blotting were used to detect the apoptosis of CSCs after treatment with Sal NPs. Immunohistochemistry and Western blotting were used to examine epithelial-mesenchymal transition (epithelial interstitial transformation) signal-related molecules. RESULTS: Sal NPs exhibited antitumor efficacy against cervical cancers by inducing apoptosis of CCSCs and inhibiting the epithelial-mesenchymal transition pathway. Besides, tumor pieces resected from Sal NP-treated mice showed decreased reseeding ability and growth speed, further demonstrating the significant inhibitory ability of Sal NPs against CSCs. Moreover, owing to targeted delivery based on the gelatinase-responsive strategy, Sal NPs was more effective and tolerable than free Sal. CONCLUSION: To the best of our knowledge, this is the first study to show that CCSC-targeted Sal NPs provide a potential approach to selectively target and efficiently eradicate CCSCs. This renders them a promising strategy to improve the therapeutic effect against cervical cancer.

Prominent Enhancement of Cisplatin Efficacy with Optimized Methoxy Poly(ethylene glycol)-Polycaprolactone Block Copolymeric Nanoparticles.

Chemotherapy has been one of the major standard treatments for a variety of cancers. cis-Dichlorodiamminoplatiunum (II) (cisplatin, CDDP), as one of the anticancer agents, demonstrated excellent efficacy against tumor and has been an indispensable component in chemotherapy, chemoradiation, chemo-molecular targeted therapy and chemo-immunotherapy. However, its therapeutic concentration was limited since its inevitable toxicity. Previously, we have constructed CDDPloaded nanoparticles (NPs) with mixture of poly(ethyleneglycol)-polycaprolactone (PEG-PCL) and polycarprolactone (HOPCL) by a facile method. The most optimal proportion of the two copolymers was selected through a series of physical, chemical, cytological and histological evaluations. In the present study, we explored the mechanisms of NPs and observed the in vivo antitumor effect after administrating CDDP-loaded PEG-PCL NPs. Positron emission tomography as well as computed tomography (PET/CT) were adopted for detecting tumoral metabolic activity. Images from fluorescence microscope revealed superior cellular uptake of CDDP-loaded NPs with rhodamine B aggregated intracellularly in cancer cells. Similar apoptotic rates between free CDDP group and CDDP-loaded NPs group was measured by flow cytometry. Tumor volumes and murine weights confirmed the superiority of CDDP-loaded NPs in therapeutic efficacy as compared with free CDDP. Blood tests showed milder side effects in CDDP-loaded nanoparticle group. PET/CT images illustrated less uptake intensity of FDG in mice received CDDP-loaded NPs than free CDDP. Our results suggest that PEG-PCL/PCL NPs could be a promising antitumor drug carrier for CDDP delivery with solid efficacy and minor side effects.

Polymer/silica hybrid hollow nanospheres with pH-sensitive drug release in physiological and intracellular environments.

Hybrid hollow nanospheres of chitosan-silica templated by chitosan-poly(acrylic acid) nanoparticles are fabricated in a complete aqueous system, which provide a pH-sensitive switch in physiological and sub-cell environments for the release of loaded drug.

Superior antitumor efficiency of cisplatin-loaded nanoparticles by intratumoral delivery with decreased tumor metabolism rate.

cis-Dichlorodiamminoplatinum (II) (cisplatin) has demonstrated extraordinary activities against a variety of solid tumors. However, the clinical efficacy is contrasted by its toxicity profile. To reduce the toxicity and enhance the circulation time of cisplatin, core-shell structure nanoparticles were prepared from block copolymer of methoxy poly(ethylene glycol)-polycaprolactone (mPEG-PCL). Cisplatin was incorporated into the nanoparticles with high encapsulation efficiency more than 75%. Controlled release of cisplatin was observed in a sustained manner. In vitro cytotoxicity studies proved the efficacy of cisplatin-loaded nanoparticles against BGC823 and H(22) cells in a dose and time-dependent manner. Furthermore, intratumoral administration was applied to improve the tumor-targeted delivery in the in vivo evaluation. Compared with free cisplatin, cisplatin-loaded nanoparticles exhibited superior antitumor effect by delaying tumor growth when delivered intratumorally, while no significant improvement was observed when they were administrated intraperitoneally. Positron emission tomography/computed tomography (PET/CT) imaging was utilized for the first time to detect the declined (18)F-labeled 2-fluoro-2-deoxy-d-glucose ((18)F-FDG) uptake of the tumor in mice receiving cisplatin-loaded nanoparticles intratumorally. These results suggest that polymeric nanoparticles with core-shell structures are promising for further studies as drug delivery carriers, and intratumoral delivery of drug-loaded nanoparticles could be a probable clinically useful therapeutic regimen.

Facile Optimization and Evaluation of PEG-PCL Block Copolymeric Nanoparticles for Anticancer Drug Delivery Using Copolymer Hybrids and Histoculture Drug Response Assays.

The traditional method of optimizing poly(ethyleneglycol)-polycaprolactone (PEG-PCL) copolymers for drug delivery requires high reaction temperatures, long reaction times, and various organic reagents. Furthermore, the in vivo evaluations of the antitumor effects of these drug delivery systems are time consuming, with animal sacrifice, and negative environmental effects. In this paper, nanoparticles (NPs) prepared from PEG-PCL/PCL hybrids were obtained by mixing PEG-PCL and PCL copolymer in different proportions and used to deliver cisplatin, a widely used anticancer drug. Histoculture drug response assay (HDRA), a predictive method typically used to evaluate chemosensitivity, was applied to evaluate the in vivo antitumor potencies of the NPs. The PEG-PCL and PCL proportions of the PEG-PCL/PCL hybrid were found to affect the NP diameter, drug loading content, encapsulation efficiency, stability, in vitro release properties, in vitro cytotoxicity, and antitumor effect in HDRA. The optimal NPs exhibited a satisfactory antitumor effect along with comparatively low side effects during an in vivo study in a murine model. The results reveal that PEG-PCL/PCL hybrids and HDRA can be used to conveniently and easily optimize and evaluate NPs prepared from block copolymers.

Gambogic acid-loaded biomimetic nanoparticles in colorectal cancer treatment.

Gambogic acid (GA) is expected to be a potential new antitumor drug, but its poor aqueous solubility and inevitable side effects limit its clinical application. Despite these inhe rent defects, various nanocarriers can be used to promote the solubility and tumor targeting of GA, improving antitumor efficiency. In addition, a cell membrane-coated nanoparticle platform that was reported recently, unites the customizability and flexibility of a synthetic copolymer, as well as the functionality and complexity of natural membrane, and is a new synthetic biomimetic nanocarrier with improved stability and biocompatibility. Here, we combined poly(lactic-co-glycolic acid) (PLGA) with red blood-cell membrane (RBCm), and evaluated whether GA-loaded RBCm nanoparticles can retain and improve the antitumor efficacy of GA with relatively lower toxicity in colorectal cancer treatment compared with free GA. We also confirmed the stability, biocompatibility, passive targeting, and few side effects of RBCm-GA/PLGA nanoparticles. We expect to provide a new drug carrier in the treatment of colorectal cancer, which has strong clinical application prospects. In addition, the potential antitumor drug GA and other similar drugs could achieve broader clinical applications via this biomimetic nanocarrier.

Human cytotoxic T-lymphocyte membrane-camouflaged nanoparticles combined with low-dose irradiation: a new approach to enhance drug targeting in gastric cancer.

Cell membrane-derived nanoparticles are becoming more attractive because of their ability to mimic many features of their source cells. This study reports on a biomimetic delivery platform based on human cytotoxic T-lymphocyte membranes. In this system, the surface of poly-lactic-co-glycolic acid nanoparticles was camouflaged using T-lymphocyte membranes, and local low-dose irradiation (LDI) was used as a chemoattractant for nanoparticle targeting. The T-lymphocyte membrane coating was verified using dynamic light scattering, transmission electron microscopy, and confocal laser scanning microscopy. This new platform reduced nanoparticle phagocytosis by macrophages to 23.99% (P=0.002). Systemic administration of paclitaxel-loaded T-lymphocyte membrane-coated nanoparticles inhibited the growth of human gastric cancer by 56.68% in Balb/c nude mice. Application of LDI at the tumor site significantly increased the tumor growth inhibition rate to 88.50%, and two mice achieved complete remission. Furthermore, LDI could upregulate the expression of adhesion molecules in tumor vessels, which is important in the process of leukocyte adhesion and might contribute to the localization of T-lymphocyte membrane-encapsulated nanoparticles in tumors. Therefore, this new drug-delivery platform retained both the long circulation time and tumor site accumulation ability of human cytotoxic T lymphocytes, while local LDI could significantly enhance tumor localization.

Antitumor and antimetastatic effects of pemetrexed-loaded targeted nanoparticles in B16 bearing mice.

Using nanoparticle delivery for anticancer therapy is a potential new drug modality. We developed a novel gelatinase-stimuli nanoparticle. In this study, we studied the antitumor and antimetastasis effect of pemetrexed-loaded targeted nanoparticles and evaluated the correlation between E-cadherin expression and lung metastasis in subcutaneous xenograft model. Compared with free pemetrexed, pemetrexed-loaded targeted nanoparticles exhibited the best antitumor and antimetastasis efficacy among the four therapeutic groups. The study also indicated that there was an inverse correlation between lung metastasis and E-cadherin expression. These results showed pemetrexed-loaded targeted nanoparticles may be a potent drug for tumor therapy and our preclinical data could provide new direction for clinical therapy of malignant melanoma.

Enhancement of radiotherapy efficacy by docetaxel-loaded gelatinase-stimuli PEG-Pep-PCL nanoparticles in gastric cancer.

Docetaxel (DOC) is widely used as radiosensitizer in various tumors, including gastric cancer (GC), but its therapeutic effect remains to be improved. In this study, using docetaxel-loaded nanoparticles (DOC-NPs) based on gelatinase-stimuli strategy, we compared their radioenhancement efficacy with docetaxel in GC. Compared with DOC, radiosensitization of DOC-NPs was improved significantly (sensitization enhancement ratio increased 1.09-fold to 1.24-fold, P<0.01) in all three gelatinase overexpressing GC cells, while increased slightly (1.02-fold, P=0.38) in gelatinase deficient normal gastric mucosa cells. The improved radiosensitization efficacy was associated with enhanced G2/M arrest, increased reactive oxygen species (ROS), more effective DSBs and promoted apoptosis. More importantly, the radiosensitization efficacy of DOC-NPs (estimated as ''very active'') was more prominent than DOC (estimated as ''moderately active'') by intravenous injection in xenograft. In conclusion, DOC-NPs are highly selective radiosensitizers in gelatinase over-expressing tumors, and more effective than DOC. By manipulating the common microenvironment difference between tumor and normal tissue, gelatinase-mediated nanoscale delivery system serves as a potential strategy possessing both universality and selectivity for radiosensitizers.

Enhancement of radiotherapy efficacy by miR-200c-loaded gelatinase-stimuli PEG-Pep-PCL nanoparticles in gastric cancer cells.

Radiotherapy is the main locoregional control modality for many types of unresectable tumors, including gastric cancer. However, many patients fail radiotherapy due to intrinsic radioresistance of cancer cells, which has been found to be strongly associated with cancer stem cell (CSC)-like properties. In this study, we developed a nanoparticle formulation to deliver miR-200c, which is reported to inhibit CSC-like properties, and then evaluated its potential activity as a radiosensitizer. miR-200c nanoparticles significantly augmented radiosensitivity in three gastric cancer cell lines (sensitization enhancement ratio 1.13-1.25), but only slightly in GES-1 cells (1.06). In addition to radioenhancement, miR-200c nanoparticles reduced the expression of CD44, a putative CSC marker, and the percentage of CD44(+) BGC823 cells. Meanwhile, other CSC-like properties, including invasiveness and resistance to apoptosis, could be suppressed by miR-200c nanoparticles. CSC-associated radioresistance mechanisms, involving reactive oxygen species levels and DNA repair capacity, were also attenuated. We have demonstrated that miR-200c nanoparticles are an effective radiosensitizer in gastric cancer cells and induce little radiosensitization in normal cells, which suggests that they are as a promising candidate for further preclinical and clinical evaluation.

Intelligently targeted drug delivery and enhanced antitumor effect by gelatinase-responsive nanoparticles.

AIMS: The matrix metalloproteinase (MMP) 2/9, also known as collagenases IV and gelatinases A/B, play a key role in cancer invasion and metastasis. However, the clinical trials of the MMP inhibitors (MMPIs) ended up with disappointing results. In this paper, we synthesized a gelatinase-responsive copolymer (mPEG-PCL) by inserting a gelatinase cleavable peptide (PVGLIG) between mPEG and PCL blocks of mPEG-PCL for anticancer drug delivery to make use of MMP2/9 as an intelligent target for drug delivery. MATERIALS AND METHODS: mPEG-pep-PCL copolymer was synthesized via ring-opening copolymerization and double-amidation. To evaluate whether Nanoparticles (NPs) prepared from this copolymer are superior to NPs prepared from mPEG-PCL, NPs prepared from mPEG-PCL copolymer were used as positive control. Docetaxel-loading NPs using mPEG-pep-PCL and mPEG-PCL were prepared by nano-precipitation method, mentioned as Gel-NPs and Con-NPs, respectively. The morphologic changes of the NPs after treatment with gelatinases were observed macroscopically by spectrophotometer and microscopically by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The cellular uptake amount and cytotoxicity of Gel-NPs and Con-NPs, respectively, in cell lines with different levels of gelatinase expression were studied. Moreover, the cytotoxicity study on the primary cancer cells isolated from pericardial fluids from a patient with late-stage lung cancer was conducted. RESULTS: The Gel-NPs aggregated in response to gelatinases, which was confirmed macroscopically and microscopically. The cellular uptake amount of Gel-NPs was correlated with the level of gelatinases. The in vitro antitumor effect of Gel-NPs was also correlated with the level of gelatinases and was superior to Taxotere (commercially available docetaxel) as well as the Con-NPs. The cytotoxicity study on the primary lung cancer cells also confirmed the effectiveness of Gel-NPs. CONCLUSION: The results in this study preliminarily demonstrated the effectiveness of gelatinase-responsive targeting strategy and the prospect of this intelligent nano-drug delivery system though further studies are needed.

Tumor accumulation, penetration, and antitumor response of cisplatin-loaded gelatin/poly(acrylic acid) nanoparticles.

In this report, the cisplatin (CDDP)-loaded gelatin/poly(acrylic acid) (GEL-PAA) nanoparticles with a spherical shape and drug loading content of 24.6% were prepared. In vivo near-infrared fluorescence (NIRF) imaging and ex vivo gamma scintillation counting analyses reveal that CDDP-loaded GEL-PAA nanoparticles have prominent passive tumor-targeting ability and the nontarget nanoparticles can be readily excreted from the body. Further, it is demonstrated that the CDDP-loaded nanoparticles have the ability to penetrate the tumor after their extravasation through the leaky vessels and distribute in a distance of about 20 µm from the vessels at 24 h postinjection. The in vivo antitumor responses reveal that the nanoparticle formulation exhibits significantly superior in vivo antitumor effect than free CDDP by the comparison of tumor volume and the examinations of cell apoptosis and proliferation in tumor tissues through proliferating cell nuclear antigen (PCNA) and terminal deoxynucleotidyl-transferase-mediated nick end labeling (TUNEL) methods.