Aims and background: Endostatin can inhibit tumor endothelial cell proliferation, angiogenesis, and growth. We aimed to determine the increase in antitumor capabilities of recombinant human endostatin (rhES) when used with a nanocarrier system. The effect of gold nanoshell particles of recombinant human endostatin (G-rhES) with near-infrared (NIR) irradiation on proliferation, inhibition, and apoptosis of A549 lung cancer cells was studied.
Materials and methods: Gold nanoshell particles were prepared. Endostatin was connected with the bond A-U through surface modification by bioconjugation of core-shell structured gold nanoshells. The drug targeting endostatin and the synthesized G-rhES were successfully connected. G-rhES inhibited proliferation of A549 lung cancer cells, as detected using tetrazolium colorimetric assay. Cellular apoptosis was measured by flow cytometry. Mitochondrial membrane potential was determined using a confocal microscope. Morphological changes were studied by atomic force microscopy.
Results: Under irradiation in the 820 nm NIR, G-rhES significantly inhibited the proliferation of A549 lung cancer cells. The underlying mechanism may be related to heat-induced apoptosis and cytotoxicity by NIR absorption, which kills cells directly, thereby indicating that G-rhES have good biocompatibility and pharmacological potency. Characterization of the local structure of lung cancer cells showed that G-rhES targeted surface receptors that may serve an apoptotic function under NIR exposure. NIR gold nanoshell particles showed synergism with endostatin, which may be related to hyperthermia-increased cytotoxicity and the apoptotic effect of endostatin.
Conclusion: These data suggest that G-rhES can enhance the inhibition of tumor growth. The new treatment strategy of G-rhES combined with thermal therapy may lead to lung cancer remission. The potential benefits of G-rhES are being considered for clinical evaluation.
Keywords: Gold nanoshells; lung cancer; recombinant human endostatin.