image: Schematic illustration of strategies for treatment of hypoxic tumor with nanomaterials. view more
Credit: ©Science China Press
Hypoxia is a typical characteristic of most tumors, owing to the fast consumption of oxygen by tumor tissue over the supply through malformed and abnormal tumor vasculature. Hypoxia in tumor tissue promotes the probability of tumor metastasis and endows hypoxia-tolerant tumor cells with resistance to some tumor therapies, including chemotherapy, radiotherapy, photodynamic therapy, and immunotherapy.
Nanomaterials have been rapidly developed, which opens up new areas in biomedical applications. Nanomaterials equipped with drugs are easier to accumulate in tumor tissues compared with small molecules. Also, nanomaterials are facile to be modified and armed with enhancive multi-functions, which is favorable for tumor therapy.
One strategy is to directly elevate the oxygen level in tumor tissues. Oxygen-carrying nanomaterials, oxygen-generating nanomaterials, and oxygen-economizing nanomaterials are utilized to relieve the hypoxic tumor environment. As the oxygen level elevates in tumor site, the resistance to tumor therapies of hypoxia-tolerant tumor cells is reduced and the tumor therapies are more effective.
Another strategy is to diminish oxygen dependence. It is readily comprehensible that therapies independent with oxygen are powerful weapons to treat hypoxic tumors. Free radicals are substances with strong oxidizing properties, which can induce cell death. Radical-generating nanomaterials can be used to treat tumor with oxygen dependence. Besides, some gaseous molecules play an essential role in physiological modulation, and therapeutic gas-generating nanomaterials can control the delivery of gas for hypoxic tumor therapy.
In a new overview published in the Beijing-based National Science Review, scientists at Wuhan University and South-Central University for Nationalities, China present the latest advances on nanomaterials for the treatment of hypoxic tumors. Xian-Zheng Zhang et al. summarized nanomaterials for treatment of hypoxic tumor with different strategies: 1) Elevating oxygen level in tumor by nanomaterials (oxygen-carrying nanomaterials, oxygen-generating nanomaterials, oxygen-economizing nanomaterials) for enhanced oxygen-dependent tumor therapy and 2) diminishing oxygen dependence of nanomaterials (therapeutic gas-generating nanomaterials and radical-generating nanomaterials) for hypoxic tumor therapy are reviewed.
They also outlined the potential development direction of future nanomaterials for treatment of hypoxic tumors. "Oxygen-carrying nanomaterials or oxygen-generating nanomaterials are hard to continually alleviate the hypoxia for tumor therapy," Zhang said. "It is necessary to develop nanomaterials with controllable and sustained release of oxygen in tumor site, which may be favorable for synergistic therapy."
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This research received funding from the National Natural Science Foundation of China.
See the article:
Mei-Zhen Zou, Wen-Long Liu, Han-Shi Chen, Xue-Feng Bai, Fan Gao, Jing-Jie Ye, Han Cheng, Xian-Zheng Zhang
Advances on nanomaterials for treatment of hypoxic tumor
National Science Review, nwaa160
https://doi.org/10.1093/nsr/nwaa160
The National Science Review is the first comprehensive scholarly journal released in English in China that is aimed at linking the country's rapidly advancing community of scientists with the global frontiers of science and technology. The journal also aims to shine a worldwide spotlight on scientific research advances across China.
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National Science Review