Hypoxia-Responsive Golgi-Targeted Prodrug Assembled with Anthracycline for Improved Antitumor and Antimetastasis Efficacy.

Tumor metastasis is an intricate multistep process regulated via various proteins and enzymes modified and secreted by swollen Golgi apparatus in tumor cells. Thus, Golgi complex is considered as an important target for the remedy of metastasis. Currently, Golgi targeting technologies are mostly employed in Golgi-specific fluorescent probes for diagnosis, but their applications in therapy are rarely reported. Herein, we proposed a prodrug (INR) that can target and destroy the Golgi apparatus, which consisted of indomethacin (IMC) as the Golgi targeting moiety and retinoic acid (RA), a Golgi disrupting agent. The linker between IMC and RA was designed as a hypoxia-responsive nitroaromatic structure, which ensured the release of the prototype drugs in the hypoxic tumor microenvironment. Furthermore, INR could be assembled with pirarubicin (THP), an anthracycline, to form a carrier-free nanoparticle (NP) by emulsion-solvent evaporation method. A small amount of mPEG2000-DSPE was added to shield the positive charges and improve the stability of the nanoparticle to obtain PEG-modified nanoparticle (PNP). It was proved that INR released the prototype drugs in tumor cells and hypoxia promoted the release. The Golgi destructive effect of RA in INR was amplified owing to the Golgi targeting ability of IMC, and IMC also inhibited the protumor COX-2/PGE2 signaling. Finally, PNP exhibited excellent curative efficacy on 4T1 primary tumor and its pulmonary and hepatic metastasis. The small molecular therapeutic prodrug targeting Golgi apparatus could be adapted to multifarious drug delivery systems and disease models, which expanded the application of Golgi targeting tactics in disease treatment.

A MnAl double adjuvant nanovaccine to induce strong humoral and cellular immune responses.

At present, the most widely used aluminum adjuvants have poor ability to induce effective Th1 type immune responses. Existing evidence suggests that manganese is a potential metal adjuvant by activating cyclic guanosine phospho-adenosine synthase (cGAS)-interferon gene stimulator protein (STING) signaling pathway to enhance humoral and cellular immune response. Hence, the effective modulation of metal components is expected to be a new strategy to improve the efficiency of vaccine immunization. Here, we constructed a manganese and aluminum dual-adjuvant antigen co-delivery system (MnO2-Al-OVA) to enhance the immune responses of subunit vaccines. Namely, the aluminum hydroxide was first fused on the surface of the pre-prepared MnO2 nanoparticles, which were synthesized by a simple redox reaction with potassium permanganate (KMnO4) and oleic acid (OA). The engineered MnO2-Al-OVA could remarkably promote cellular internalization and maturation of dendritic cells. After subcutaneous vaccination, MnO2-Al-OVA rapidly migrated into the lymph nodes (LNs) and efficiently activate the cGAS-STING pathway, greatly induced humoral and cellular immune responses. Of note, our findings underscore the importance of coordination manganese adjuvants in vaccine design by promoting the activation of the cGAS-STING-IFN-I pathway. With a good safety profile and facile preparation process, this dual-adjuvant antigen co-delivery nanovaccine has great potential for clinical translation prospects.

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.

Single-shot AAV-vectored vaccine against SARS-CoV-2 with fast and long-lasting immunity.

Due to the insufficient long-term protection and significant efficacy reduction to new variants of current COVID-19 vaccines, the epidemic prevention and control are still challenging. Here, we employ a capsid and antigen structure engineering (CASE) strategy to manufacture an adeno-associated viral serotype 6-based vaccine (S663V-RBD), which expresses trimeric receptor binding domain (RBD) of spike protein fused with a biological adjuvant RS09. Impressively, the engineered S663V-RBD could rapidly induce a satisfactory RBD-specific IgG titer within 2 weeks and maintain the titer for more than 4 months. Compared to the licensed BBIBP-CorV (Sinopharm, China), a single-dose S663V-RBD induced more endurable and robust immune responses in mice and elicited superior neutralizing antibodies against three typical SARS-CoV-2 pseudoviruses including wild type, C.37 (Lambda) and B.1.617.2 (Delta). More interestingly, the intramuscular injection of S663V-RBD could overcome pre-existing immunity against the capsid. Given its effectiveness, the CASE-based S663V-RBD may provide a new solution for the current and next pandemic.

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.

Albumin-biomineralized nanoparticles to synergize phototherapy and immunotherapy against melanoma.

To date, cancer phototherapy remains as an unsatisfactory method of cancer treatment due to the high probability of cancer recurrence - an effect that is partly driven by tumor-driven immunosuppression. Therefore, we propose inducing adequate immune responses after photo tumor ablation may be critical to achieve a long term therapeutic effect of phototherapy. Here, we engineered the photosensitizer chlorin e6 (Ce6) and the time-honored immunoadjuvant aluminum hydroxide into bovine serum albumin by albumin-based biomineralization as a novel nanosystem (Al-BSA-Ce6 NPs). After intravenous injection, the nanoparticles not only destroyed tumor cells effectively but also protected animals against tumor rechallenge and metastasis by strongly inducing a systemic anti-tumor immune response. Subsequent analysis demonstrated T cells accumulated in lymph nodes and infiltrated the tumor site, elevating levels of immune indicators including serum antibody, cytokine level and higher proportions of cytotoxic T cells and Th1 cells. These protective effects were not observed with commercially available alumina gels, or when the aluminum hydroxide in the nanoparticles was replaced with ferric hydroxide. Therefore, we present Al-BSA-Ce6 NPs as a novel and unique system for alumina adjuvants that serves as an effective approach for cancer therapy.