This paper described the energy-transfer amplified singlet oxygen generation in semiconductor polymer dots (Pdots) for in vitro and in vivo photodynamic therapy. Hydrophobic photosensitizer tetraphenylporphyrin was facilely doped in the nanoparticles consisting of densely packed semiconductor polymers. Optical characterizations indicated that the fluorescence of Pdots was completely quenched by the photosensitizer, yielding an energy transfer efficiency of nearly 100% and singlet-oxygen generation quantum yield of ∼50%. We evaluated the cellular uptake, dark toxicity, and photodynamic therapy of the Pdot photosensizer in human gastric adenocarcinoma cells. The in vitro studies indicated that cancer cells were efficiently destroyed at very low dose of the Pdots such as 1 μg/mL by using the light dose of 90 J/cm(2), which is considerably less than that in clinical practice. The antitumor effect of the Pdots was further evaluated in vivo with human gastric adenocarcinoma xenografts in Balb/c nude mice, which show that the xenograft tumors were significantly inhibited and eradicated in some cases. Our results indicate the energy transfer amplified Pdot platforms have great therapeutic potential for treating malignant cancers.

Background: Previous studies have shown that lncRNA LINC00662 plays an important role in pathogenesis of malignancies. The purpose of this study was to elucidate the regulatory mechanism of LINC00662 in esophageal squamous cell carcinoma (ESCC). Methods: In this study, the regulatory mechanism of LINC00662 was investigated by RT-qPCR. MTT, transwell and dual luciferase reporter assays. Results: Upregulation of LINC00662 was found in ESCC and associated with worse clinical outcomes in ESCC patients. More importantly, knockdown of LINC00662 restrained cell proliferation, migration and invasion in ESCC. In addition, LINC00662 acts as a molecular sponge for miR-340-5p in ESCC, and miR-340-5p directly targets HOXB2. HOXB2 expression can be positively regulated by LINC00662 in ESCC. Furthermore, HOXB2 downregulation or miR-340-5p overexpression weakened the carcinogenesis of LINC00662 in ESCC. Conclusions: LncRNA LINC00662 promotes the progression of ESCC by upregulating HOXB2 by sponging miR-340-5p.

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