Mitochondria-targeting graphene oxide nanocomposites for fluorescence imaging-guided synergistic phototherapy of drug-resistant osteosarcoma.

BACKGROUND: Osteosarcoma (OS) is the most common primary malignant bone tumor occurring in children and young adults. Drug-resistant osteosarcoma often results in chemotherapy failure. Therefore, new treatments aimed at novel therapeutic targets are urgently needed for the treatment of drug-resistant osteosarcoma. Mitochondria-targeted phototherapy, i.e., synergistic photodynamic/photothermal therapy, has emerged as a highly promising strategy for treating drug-resistant tumors. This study proposed a new nano-drug delivery system based on near-infrared imaging and multifunctional graphene, which can target mitochondria and show synergistic phototherapy, with preferential accumulation in tumors. METHODS AND RESULTS: Based on our previous study, (4-carboxybutyl) triphenyl phosphonium bromide (TPP), a mitochondria-targeting ligand, was conjugated to indocyanine green (ICG)-loaded, polyethylenimine-modified PEGylated nanographene oxide sheets (TPP-PPG@ICG) to promote mitochondrial accumulation after cellular internalization. Thereafter, exposure to a single dose of near-infrared irradiation enabled synergistic photodynamic and photothermal therapy, which simultaneously inhibited adenosine triphosphate synthesis and mitochondrial function. Induction of intrinsic apoptosis assisted in surmounting drug resistance and caused tumor cell death. After fluorescence imaging-guided synergistic phototherapy, the mitochondria-targeting, multifunctional graphene-based, drug-delivery system showed highly selective anticancer efficiency in vitro and in vivo, resulting in marked inhibition of tumor progression without noticeable toxicity in mice bearing doxorubicin-resistant MG63 tumor cells. CONCLUSION: The mitochondria-targeting TPP-PPG@ICG nanocomposite constitutes a new class of nanomedicine for fluorescence imaging-guided synergistic phototherapy and shows promise for treating drug-resistant osteosarcoma.

[Effects of ferrous sulfate supplementation on bone marrow hemopoiesis in rats].

OBJECTIVE: To explore the influences of different dosage ferrous sulfate supplements on bone marrow hemopoiesis in rats. METHODS: Female weaning Wistar rats were fed with an iron deficient diet (< 10 mg/kg diet) until the level of hemoglobin of rats was lower than 100 g/L. Rats (n = 50) were randomly divided into five groups according to the levels of hemoglobin and body weight, iron deficiency control (ID), daily low iron diet supplement (LDs), daily high iron diet supplement (HDs), weekly low iron supplement (LWs), and weekly high iron supplement (HWs). RESULTS: After 12 weeks, bone marrow stainable iron was seldom in ID group, and ample in supplement groups. The proportions of iron staining of bone marrow smear in supplement groups were more than 30%. Bone marrow cells in all rats were hyperplastic or active hyperplastic. CONCLUSIONS: Daily high iron supplement or once weekly high iron supplement were safe to bone marrow hemopoiesis in rats.