Xudong Zhang

Patients with low-immunogenic tumors respond poorly to immune checkpoint blockade (ICB) targeting the programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) pathway. Conversely, patients responding to ICB can experience various side effects. We have thus engineered a therapeutic scaffold that, when formed in situ, allows the local release of gemcitabine (GEM) and an anti-PD-L1 blocking antibody (aPDL1) with distinct release kinetics. The scaffold consists of reactive oxygen species (ROS)-degradable hydrogel that releases therapeutics in a programmed manner within the tumor microenvironment (TME), which contains abundant ROS. We found that the aPDL1-GEM scaffold elicits an immunogenic tumor phenotype and promotes an immune-mediated tumor regression in the tumor-bearing mice, with prevention of tumor recurrence after primary resection.

The facultative anaerobe Salmonella strain VNP20009 selectively colonizes into tumors following systemic injection due to its preference for the hypoxia in the tumor cores. However, the phase 1 clinical trial of VNP20009 has been terminated mainly due to its weak antitumor effects and exhibition of dose-dependent toxicity. Here, we leveraged the advantages of VNP20009 biotherapy together with polydopamine-mediated photothermal therapy in order to enhance the antitumor efficacy toward malignant melanoma. VNP20009 was coated with polydopamine via oxidation and self-polymerization, which was then injected into tumor-bearing mice via the tail vein. Polydopamine-coated VNP20009 targeted hypoxic areas of the solid tumors, and near-infrared laser irradiation of the tumors induced heating due to polydopamine. This combined approach eliminated the tumors without relapse or metastasis with only one injection and laser irradiation. More importantly, we found both VNP and pDA potentiate the therapeutic ability of each other, resulting in a superior anticancer effect.

Melanin is capable of transforming 99.9% of the absorbed sunlight energy into heat, reducing the risk of skin cancer. We here develop a melanin-mediated cancer immunotherapy strategy through a transdermal microneedle patch. B16F10 whole tumor lysate containing melanin is loaded into polymeric microneedles that allow sustained release of the lysate upon insertion into the skin. In combination with the near-infrared light irradiation, melanin in the patch mediates the generation of heat, which further promotes tumor-antigen uptake by dendritic cells, and leads to enhanced antitumor vaccination. We found that the spatiotemporal photoresponsive immunotherapy increases infiltration of polarized T cells and local cytokine release. These immunological effects increase the survival of mice after tumor challenge and elicited antitumor effects toward established primary tumor and distant tumor. Collectively, melanin generates local heat, boosts T cell activities by transdermal vaccines, and promotes antitumor immune responses.