Cancer recurrence after surgical resection (SR) is a considerable challenge, and the biological effect of SR on the tumor microenvironment (TME) that is pivotal in determining postsurgical treatment efficacy remains poorly understood. Here, with an experimental model, we demonstrate that the genomic landscape shaped by SR creates an immunosuppressive milieu characterized by hypoxia and high-influx of myeloid cells, fostering cancer progression and hindering PD-L1 blockade therapy. To address this issue, we engineer a radio-immunostimulant nanomedicine (IPI549@HMP) capable of targeting myeloid cells, and catalyzing endogenous H 2 O 2 into O 2 to achieve hypoxia-relieved radiotherapy (RT). The enhanced RT-mediated immunogenic effect results in postsurgical TME reprogramming and increased susceptibility to anti-PD-L1 therapy, which can suppress/eradicate locally residual and distant tumors, and elicits strong immune memory effects to resist tumor rechallenge. Our radioimmunotherapy points to a simple and effective therapeutic intervention against postsurgical cancer recurrence and metastasis.
Fangmei Zhang,Shikai Liu,Na Zhang,Ye Kuang,Wenting Li,Shili Gai,Fei He,Arif Gulzar,Piaoping Yang
Hypoxia in tumor cells is regarded as the most crucial cause of clinical drug resistance and radio-resistance; thus, relieving hypoxia of tumor cells is the key to enhancing the efficacy of anticancer therapy. As a gas signal molecule of vasodilatation factors, nitric oxide (NO) can relieve the hypoxia status of tumor cells, thereby, enhancing the sensitivity of tumor cells to radiotherapy. However, considering complications of vascular activity, the level of NO required for radiotherapy sensitization cannot be obtained in vivo. In view of this, we design and fabricate a multifunctional bismuth-based nanotheranostic agent, which is functionalized with S-nitrosothiol and termed Bi–SNO NPs. X-rays break down the S–N bond and simultaneously trigger large amount of NO-releasing (over 60 μM). Moreover, the as-prepared Bi–SNO NPs not only possess the capability of absorbing and converting 808 nm NIR photons into heat for photothermal therapy, but also have the ability to increase X-ray absorption and CT imaging sensitivity. In addition, the collaborative radio-, photothermal-, and gas-therapy of Bi–SNO in vivo was further investigated and remarkable synergistic tumor inhibition was realized. Finally, no obvious toxicity of Bi–SNO NPs was observed in the treated mice within 14 days. Therefore, the Bi–SNO developed in this work is an effective nano-agent for cancer theranostics with well-controlled morphology and uniform size (36 nm), which could serve as a versatile CT imaging-guided combined radio-, photothermal- and gas-therapy nanocomposite with negligible side effects.
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