Preparation, characterization, in vitro and in vivo anti-tumor effect of thalidomide nanoparticles on lung cancer.

INTRODUCTION: Thalidomide (THA) is an angiogenesis inhibitor and an efficient inhibitor of the tumor necrosis factor-α (TNF-α). However, the clinical application of THA has been limited due to hydrophobicity of the compound. MATERIALS AND METHODS: To increase the water solubility of THA and in order to evaluate the anticancer abilities of this material on human lung carcinoma, methoxy poly(ethylene glycol)-poly(ε-caprolactone) nanoparticles loaded with THA (THA-NPs) were prepared. The synthesis of THA-NPs was carried out via a dialysis method with relative satisfactory encapsulation efficiency, loading capacity, size distribution, and zeta potential. RESULTS: A cytotoxicity assay demonstrated that THA-NPs inhibited the growth of cells in a dose-dependent manner. The evaluation of anti-tumor activity in vivo showed that THA-NPs could inhibit tumor growth and prolong the survival rate of tumor-bearing mice. Immunohistochemical analysis indicated that THA-NPs inhibited cell proliferation (Ki-67 positive rate, 32.8%±4.2%, P<0.01), and resulted in a decreased rate of the tumor tissue microvessel density (3.87%±0.77%, P<0.01), VEGF (26.67%±4.02%, P<0.01), and TNF-α (75.21±6.85 ng/mL, P<0.01). CONCLUSION: In general, the drug delivery system reported herein may shed light on future targeted therapy in lung cancer treatment.

In vitro and in vivo antitumor effect of gefitinib nanoparticles on human lung cancer.

Gefitinib (GEF) is the first epidermal growth factor receptor (EGFR)-targeting agent launched as an anticancer drug. It is an accepted opinion that modifying GEF strong hydrophobicity and poor bioavailability would not only enhance its antitumor effects, but also reduce its side effects. In this study, GEF-loadedpoly(ε-caprolactone)-poly(ethyleneglycol)-poly(ε-caprolactone) (PCEC) -bearing nanoparticles (GEF-NPs) were prepared by a solid dispersion method and characterized. The particle sizes increased with the increase in GEF/PCEC mass ratio in feed. GEF-NPs (10%) were mono-dispersed, smaller than 24 nm, zeta potential was approximately -18 mV, percentage encapsulation and loading, were more than 9% and 92%, respectively, and drug was slowly released but without a biphasic pattern. Microscopy studies of the optimized formulation confirmed that the prepared nanoparticles are spherical in nature. Cytotoxicity results indicated that cell growth inhibition induced by free GEF and GEF-NPs were dose and time dependent. Compared with free GEF, GEF-NPs enhanced antitumor effects, reduced side effects and significantly prolonged survival time in vivo. CD31, ki-67 and EGFR expression were significantly lower in the GEF-NPs group compared with other groups (p< .05). These findings demonstrated that GEF-NPs have the potential to attain superior outcomes and to overcome complications such as organs toxicity, therapeutic resistance and disease relapse.

Periostin Promotes Neural Stem Cell Proliferation and Differentiation following Hypoxic-Ischemic Injury.

Neural stem cell (NSC) proliferation and differentiation are required to replace neurons damaged or lost after hypoxic-ischemic events and recover brain function. Periostin (POSTN), a novel matricellular protein, plays pivotal roles in the survival, migration, and regeneration of various cell types, but its function in NSCs of neonatal rodent brain is still unknown. The purpose of this study was to investigate the role of POSTN in NSCs following hypoxia-ischemia (HI). We found that POSTN mRNA levels significantly increased in differentiating NSCs. The proliferation and differentiation of NSCs in the hippocampus is compromised in POSTN knockout mice. Moreover, NSC proliferation and differentiation into neurons and astrocytes significantly increased in cultured NSCs treated with recombinant POSTN. Consistently, injection of POSTN into neonatal hypoxic-ischemic rat brains stimulated NSC proliferation and differentiation in the subventricular and subgranular zones after 7 and 14 days of brain injury. Lastly, POSTN treatment significantly improved the spatial learning deficits of rats subjected to HI. These results suggest that POSTN significantly enhances NSC proliferation and differentiation after HI, and provides new insights into therapeutic strategies for the treatment of hypoxic-ischemic encephalopathy.

Neuroprotective effects of oligodendrocyte progenitor cell transplantation in premature rat brain following hypoxic-ischemic injury.

Periventricular leukomalacia (PVL) is a common ischemic brain injury in premature infants for which there is no effective treatment. The objective of this study was to determine whether transplanted mouse oligodendrocyte progenitor cells (OPCs) have neuroprotective effects in a rat model of PVL. Hypoxia-ischemia (HI) was induced in 3-day-old rat pups by left carotid artery ligation, followed by exposure to 6% oxygen for 2.5 h. Animals were assigned to OPC transplantation or sham control groups and injected with OPCs or PBS, respectively, and sacrificed up to 6 weeks later for immunohistochemical analysis to investigate the survival and differentiation of transplanted OPCs. Apoptosis was evaluated by double immunolabeling of brain sections for caspase-3 and neuronal nuclei (NeuN), while proliferation was assessed using a combination of anti-Nestin and -bromodeoxyuridine antibodies. The expression of brain-derived neurotrophic factor (BDNF) and Bcl-2 was examined 7 days after OPC transplantation. The Morris water maze was used to test spatial learning and memory. The results showed that transplanted OPCs survived and formed a myelin sheath, and stimulated BDNF and Bcl-2 expression and the proliferation of neural stem cells (NSC), while inhibiting HI-induced neuronal apoptosis relative to control animals. Moreover, deficits in spatial learning and memory resulting from HI were improved by OPC transplantation. These results demonstrate an important neuroprotective role for OPCs that can potentially be exploited in cell-based therapeutic approaches to minimize HI-induced brain injury.

Short-term effects of hypothermia on axonal injury, preoligodendrocyte accumulation and oligodendrocyte myelination after hypoxia-ischemia in the hippocampus of immature rat brain.

Hypothermia is known to improve neurological recovery of animals and humans exposed to hypoxic-ischemic (HI) injury. However, the underlying mechanisms of the neuroprotective effects of hypothermia are only partially understood, including decreased excitotoxicity and apoptosis, and suppressed inflammation. There are few studies about the hypothermic effects on axonal injury and oligodendrocyte (OL) lineage degeneration, which are important components of neonatal brain injuries that cause cognitive disability. We hypothesized that mild hypothermia would reduce axonal injury and increase myelination in the hippocampus after HI. We performed left carotid artery ligation followed by 8% oxygen for 2 h in 7-day-old rats. Animals were divided into a hypothermic group (rectal temperature 32-33°C for 24 h) and a normothermic group (36-37°C for 24 h) immediately after HI. Animals were sacrificed at 1, 3 and 7 days for immunohistochemistry or Western blot analysis. We detected neuron loss by microtubule-associated protein 2 labeling and axonal injury by non-phosphorylated neurofilament (SMI32) with neurofilament 200 (NF200) double staining. We examined early OL progenitors by A2B5 or NG2, preoligodendrocytes (preOLs) by O4, and mature OLs by 2,3-cyclic nucleotide 3-phosphodiesterase (CNPase) and glutathione S-transferase (GST)-pi staining. Apoptosis was studied by active caspase-3. Hypothermia was associated with a significant elevation of neurons and axons in the hippocampal CA1 region after HI. Early OL progenitors (A2B5(+)) were elevated, but preOLs (O4(+)) and active caspase-3 were dramatically reduced in the hypothermic rat brain. Further study showed that the apoptotic rate of preOLs (caspase-3(+)-O4(+)/O4(+)) was markedly attenuated by hypothermic treatment compared to normothermic animals. The immunoreactivity of CNPase and GST-pi and the protein level of the myelin basic protein significantly increased in the hippocampus of hypothermia-treated rat brain. Axonal myelination also increased in hypothermic animals, which were tested by myelin basic protein and NF200 double staining and electron microscopy. These results showed that hypothermia reduced HI damage to axons and OL myelination coincided with increased early OL progenitor proliferation and decreased preOL accumulation and apoptosis. This study suggested new aspects that may contribute to elucidate the mechanism of hypothermic neuroprotection in neonatal rat brain.