Lihong Sun

Hypoxia in a solid tumor microenvironment (TME) can lead to the overexpression of hypoxia-inducible factor-1α (HIF-1α), which correlates to tumor metastasis. Reactive oxygen species (ROS) induced tumor cell apoptosis is becoming a promising method in tumor treatment. Currently, the ROS generating systems, e.g., photodynamic treatment and sonodynamic treatment, highly depend on oxygen (O2) in the tumor microenvironment (TME). However, the level of O2 in TME is too low to produce enough ROS. Herein, we developed an ultrasmall DSPE-PEG2000 coated barium titanate nanoparticle (P-BTO) for tumor treatment based on ultrasound triggered piezocatalysis and water splitting. Interestingly, irradiated by ultrasound, the surface of ultasmall P-BTO nanoparticles produced imbalance charges, which induced a cascade of redox reaction processes to simultaneously generate ROS and O2, the latter one was hardly generated in large-sized barium titanate nanoparticles. The as-synthesized P-BTO reached the highest accumulation in the tumor site at 4 h after intravenous injection. The results showed that the produced O2 significantly alleviated the hypoxia of TME to down-regulate the expression of HIF-1α, and the produced ROS can efficiently kill tumor cells. Moreover, the tumor metastasis was also inhibited, providing a different way to treat triple-negative breast cancer, which was easily metastatic and lacked effective treatments in the clinic.

A Sri Lankan indica rice (Oryza sativa L.) cultivar Rathu Heenati was found to be resistant to all the four biotypes of the brown planthopper (BPH) (Nilaparvata lugens Stål). In the present study, we constructed a linkage map to identify the locus (loci) for the BPH resistance genes, using an F2 population from a cross between Rathu Heenati and a susceptible cultivar 02428. Insect resistance was evaluated using 156 F2:3 lines and the genotype of each F2 plant was inferred from the phenotype of the corresponding F2:3 lines. Three loci detected by QTL (quantitative trait locus) analysis, were assigned to chromosomes 3, 4 and 10. The phenotypic variance of the three QTLs indicated that the QTL on chromosome 4 is a major BPH resistance gene in Rathu Heenati. Through linkage analysis, it was found that this BPH resistance gene was located between two SSR markers RM8213 and RM5953 on the short arm of chromosome 4, with map distances of 3.6 cM and 3.2 cM, respectively. This gene, tentatively designated as Bph17, should be useful for the breeding of varieties resistant to BPH in a marker-assisted selection (MAS) program.

Indocyanine green (ICG) is capable of inducing a photothermal effect and the production of cytotoxic reactive oxygen species for cancer therapy. However, the major challenge in applying ICG molecules for antitumor therapy is associated with their instability in aqueous conditions and rapid clearance from blood circulation, which causes insufficient bioavailability at the tumor site. Herein, we conjugated ICG molecules with Prussian blue nanoparticles enclosing a Fe3O4 nanocore, which was facilitated by cationic polyethyleneimine via electrostatic adsorption. The nanocarrier-loaded ICG formed stable aggregates that enhanced cellular uptake and prevented fluorescence quenching. Moreover, the strong superparamagnetism of the Fe3O4 core in the obtained nanocomposites further improved cellular internalization of the drugs guided by a localized magnetic field. The therapeutic efficacy of this nanoplatform was evaluated using tumor models established in nude mice, which demonstrated remarkable tumor ablation in vivo due to strong photothermal/photodynamic effects. This study provides promising evidence that this multifunctional nanoagent might function as an efficient mediator for combining photothermal and photodynamic cancer therapy.