Cloaking Mesoporous Polydopamine with Bacterial Membrane Vesicles to Amplify Local and Systemic Antitumor Immunity.

As adjuvants or antigens, bacterial membranes have been widely used in recent antibacterial and antitumor research, but they are often injected multiple times to achieve therapeutic outcomes, with limitations in biosafety and clinical application. Herein, we leverage the biocompatibility and immune activation capacity of Salmonella strain VNP20009 to produce double-layered membrane vesicles (DMVs) for enhanced systemic safety and antitumor immunity. Considering the photothermal effect of polydopamine upon irradiation, VNP20009-derived DMVs are prepared to coat the surface of mesoporous polydopamine (MPD) nanoparticles, leading to the potential synergies between photothermal therapy mediated by MPD and immunotherapy magnified by DMVs. The single dose of MPD@DMV can passively target tumors and activate the immune system with upregulated T cell infiltration and secretion levels of pro-inflammatory factors as well as antitumor related cytokines. All of these promoted immune responses result in malignant melanoma tumor regression and extended survival time on local or distant tumor-bearing mouse models. Importantly, we further explore the advantages of intravenous injection of the MPD@DMV agent compared with its intratumoral injection, and the former demonstrates better long-term immune effects on animal bodies. Overall, this formulation design brings broader prospects for the autologous vaccine adjuvant by bacterial membrane vesicles in cancer therapy.

Dual drugs decorated bacteria irradiate deep hypoxic tumor and arouse strong immune responses.

Intratumoral environment as a hypoxic, non-inflamed "cold" state is difficult for many agents to accumulate and activate the immune system. Intrinsically, facultative anaerobic Salmonella VNP20009 target the tumor hypoxic areas, invade into tumor cells and exhibit an immune effect. Here we engineer the bacteria by decorating their surface with newly synthesized heptamethine cyanine dyes NHS-N782 and JQ-1 derivatives to obtain the biohybrid agent N-V-J, leading to the deep tumor targeted photothermal therapy and magnified immunotherapy. Due to the mitochondrial targeting capacity of NHS-N782, N-V-J becomes susceptive to the temperature rise when reaching tumors. This synergistic strategy promotes the systemic immunity by creating an inflamed "hot" tumor state from three different dimensions, which include the inherent immunogenicity of bacteria, the near-infrared laser triggered tumor antigens and the downregulation of PD-L1 expression. All these approaches result in effective and long-lasting T cell immune responses to prevent local and distant tumors for extended time. Leveraging the attenuated bacteria to transport dual drugs to the tumor tissues for self-synthetic vaccines provides a novel paradigm to enhance the bacteria-mediated cancer immunotherapy.

Aluminum nanoparticles deliver a dual-epitope peptide for enhanced anti-tumor immunotherapy.

Tumor peptide vaccines contain only key amino acid sequences of tumor neoantigens, and therefore can provide precise activation of immune responses. Recent research has found that short peptide vaccines restricted to MHC-I epitopes are insufficient to activate effective CD8+ T cell responses for tumor elimination, and assistance from CD4+ T cell immunity could significantly improve the therapeutic outcome. Herein, we proposed an innovative peptide vaccine strategy to simultaneously activate CD8+ and CD4+ T cell responses by combining MHC-I and MHC-II epitopes into one long peptide antigen. To further strengthen the anti-tumor immune response induced by this dual-epitope peptide, we engineered a PEG derivative (PpASE) stabilized aluminum nanoparticle for delivering the synthetic long peptides (ANLs). The synthesized nanovaccine with a diameter of ~100 nm showed good stability and enhanced antigen uptake by antigen-presenting cells (APCs). As a result, ANLs promoted the presentation of MHC-I epitope in APCs and induced stronger activation and proliferation of CD8+ T cells as compared to aluminum nanoparticle loaded with MHC-I epitope restricted peptides (ANSs). After subcutaneous vaccination, the developed nanovaccine significantly inhibited tumor growth and prolonged mouse survival in both B16-OVA and B16F10 tumor models. Finally, ANLs were also able to elevate the maturation level of human dendritic cells (DCs), showing a great possibility of clinical translation.

ULK1 phosphorylates Mad1 to regulate spindle assembly checkpoint.

The spindle assembly checkpoint (SAC) ensures the fidelity of chromosome segregation during mitosis. Here, we show that ULK1, a serine/threonine kinase that plays a key role in initiation of autophagy, also has an important function in the activation of SAC. ULK1 phosphorylates the SAC protein Mad1 at Ser546 to recruit Mad1 to kinetochores. Furthermore, Rod/ZW10/Zwilch (RZZ) complex may serve as a receptor for phos-Ser546-Mad1 at kinetochore, since phosphorylation of Mad1 by ULK1 strengthens the interaction between Mad1 and RZZ complex. In addition, deletion of ULK1 increases chromosome instability and cytotoxicity of paclitaxel, resulting in significant impairment of cancer cell growth. These findings highlight the role of ULK1 as a protein kinase controlling the fidelity of chromosome segregation and cell-cycle progression.