Lipid nanoparticle-based mRNA delivery systems for cancer immunotherapy

Bacteria extracellular vesicle as nanopharmaceuticals for versatile biomedical potential

Bacteria extracellular vesicles (BEVs), characterized as the lipid bilayer membrane-surrounded nanoparticles filled with molecular cargo from parent cells, play fundamental roles in the bacteria growth and pathogenesis, as well as facilitating essential interaction between bacteria and host systems. Notably, benefiting from their unique biological functions, BEVs hold great promise as novel nanopharmaceuticals for diverse biomedical potential, attracting significant interest from both industry and academia. Typically, BEVs are evaluated as promising drug delivery platforms, on account of their intrinsic cell-targeting capability, ease of versatile cargo engineering, and capability to penetrate physiological barriers. Moreover, attributing to considerable intrinsic immunogenicity, BEVs are able to interact with the host immune system to boost immunotherapy as the novel nanovaccine against a wide range of diseases. Towards these significant directions, in this review, we elucidate the nature of BEVs and their role in activating host immune response for a better understanding of BEV-based nanopharmaceuticals' development. Additionally, we also systematically summarize recent advances in BEVs for achieving the target delivery of genetic material, therapeutic agents, and functional materials. Furthermore, vaccination strategies using BEVs are carefully covered, illustrating their flexible therapeutic potential in combating bacterial infections, viral infections, and cancer. Finally, the current hurdles and further outlook of these BEV-based nanopharmaceuticals will also be provided.

Design of PD-L1-Targeted Lipid Nanoparticles to Turn on PTEN for Efficient Cancer Therapy

Lipid nanoparticles (LNPs) exhibit remarkable mRNA delivery efficiency, yet their majority accumulate in the liver or spleen after injection. Tissue-specific mRNA delivery can be achieved through modulating LNP properties, such as tuning PEGylation or varying lipid components systematically. In this paper, a streamlined method is used for incorporating tumor-targeting peptides into the LNPs; the programmed death ligand 1 (PD-L1) binding peptides are conjugated to PEGylated lipids via a copper-free click reaction, and directly incorporated into the LNP composition (Pep LNPs). Notably, Pep LNPs display robust interaction with PD-L1 proteins, which leads to the uptake of LNPs into PD-L1 overexpressing cancer cells both in vitro and in vivo. To evaluate anticancer immunotherapy mediated by restoring tumor suppressor, mRNA encoding phosphatase and tensin homolog (PTEN) is delivered via Pep LNPs to PTEN-deficient triple-negative breast cancers (TNBCs). Pep LNPs loaded with PTEN mRNA specifically promotes autophagy-mediated immunogenic cell death in 4T1 tumors, resulting in effective anticancer immune responses. This study highlights the potential of tumor-targeted LNPs for mRNA-based cancer therapy.

Analytical Ultracentrifugation to Assess the Quality of LNP-mRNA Therapeutics

The approval of safe and effective LNP-mRNA vaccines during the SARS-CoV-2 pandemic is catalyzing the development of the next generation of mRNA therapeutics. Proper characterization methods are crucial for assessing the quality and efficacy of these complex formulations. Here, we show that analytical ultracentrifugation (AUC) can measure, simultaneously and without any sample preparation step, the sedimentation coefficients of both the LNP-mRNA formulation and the mRNA molecules. This allows measuring several quality attributes, such as particle size distribution, encapsulation efficiency and density of the formulation. The technique can also be applied to study the stability of the formulation under stress conditions and different buffers.

Immunologic tumor microenvironment modulators for turning cold tumors hot

Tumors can be classified into distinct immunophenotypes based on the presence and arrangement of cytotoxic immune cells within the tumor microenvironment (TME). Hot tumors, characterized by heightened immune activity and responsiveness to immune checkpoint inhibitors (ICIs), stand in stark contrast to cold tumors, which lack immune infiltration and remain resistant to therapy. To overcome immune evasion mechanisms employed by tumor cells, novel immunologic modulators have emerged, particularly ICIs targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1/programmed death-ligand 1(PD-1/PD-L1). These agents disrupt inhibitory signals and reactivate the immune system, transforming cold tumors into hot ones and promoting effective antitumor responses. However, challenges persist, including primary resistance to immunotherapy, autoimmune side effects, and tumor response heterogeneity. Addressing these challenges requires innovative strategies, deeper mechanistic insights, and a combination of immune interventions to enhance the effectiveness of immunotherapies. In the landscape of cancer medicine, where immune cold tumors represent a formidable hurdle, understanding the TME and harnessing its potential to reprogram the immune response is paramount. This review sheds light on current advancements and future directions in the quest for more effective and safer cancer treatment strategies, offering hope for patients with immune-resistant tumors.

Recent Findings on Therapeutic Cancer Vaccines: An Updated Review

Cancer remains one of the global leading causes of death and various vaccines have been developed over the years against it, including cell-based, nucleic acid-based, and viral-based cancer vaccines. Although many vaccines have been effective in in vivo and clinical studies and some have been FDA-approved, there are major limitations to overcome: (1) developing one universal vaccine for a specific cancer is difficult, as tumors with different antigens are different for different individuals, (2) the tumor antigens may be similar to the body's own antigens, and (3) there is the possibility of cancer recurrence. Therefore, developing personalized cancer vaccines with the ability to distinguish between the tumor and the body's antigens is indispensable. This paper provides a comprehensive review of different types of cancer vaccines and highlights important factors necessary for developing efficient cancer vaccines. Moreover, the application of other technologies in cancer therapy is discussed. Finally, several insights and conclusions are presented, such as the possibility of using cold plasma and cancer stem cells in developing future cancer vaccines, to tackle the major limitations in the cancer vaccine developmental process.

Engineering a Programmed Death-Ligand 1-Targeting Monobody Via Directed Evolution for SynNotch-Gated Cell Therapy

Programmed death-ligand 1 (PD-L1) is a promising target for cancer immunotherapy due to its ability to inhibit T cell activation; however, its expression on various noncancer cells may cause on-target off-tumor toxicity when designing PD-L1-targeting Chimeric Antigen Receptor (CAR) T cell therapies. Combining rational design and directed evolution of the human fibronectin-derived monobody scaffold, "PDbody" was engineered to bind to PD-L1 with a preference for a slightly lower pH, which is typical in the tumor microenvironment. PDbody was further utilized as a CAR to target the PD-L1-expressing triple negative MDA-MB-231 breast cancer cell line. To mitigate on-target off-tumor toxicity associated with targeting PD-L1, a Cluster of Differentiation 19 (CD19)-recognizing SynNotch IF THEN gate was integrated into the system. This CD19-SynNotch PDbody-CAR system was then expressed in primary human T cells to target CD19-expressing MDA-MB-231 cancer cells. These CD19-SynNotch PDbody-CAR T cells demonstrated both specificity and efficacy in vitro, accurately eradicating cancer targets in cytotoxicity assays. Moreover, in an in vivo bilateral murine tumor model, they exhibited the capability to effectively restrain tumor growth. Overall, CD19-SynNotch PDbody-CAR T cells represent a distinct development over previously published designs due to their increased efficacy, proliferative capability, and mitigation of off-tumor toxicity for solid tumor treatment.

Nanoparticle-Based Immunotherapy for Reversing T-Cell Exhaustion

T-cell exhaustion refers to a state of T-cell dysfunction commonly observed in chronic infections and cancer. Immune checkpoint molecules blockading using PD-1 and TIM-3 antibodies have shown promising results in reversing exhaustion, but this approach has several limitations. The treatment of T-cell exhaustion is still facing great challenges, making it imperative to explore new therapeutic strategies. With the development of nanotechnology, nanoparticles have successfully been applied as drug carriers and delivery systems in the treatment of cancer and infectious diseases. Furthermore, nanoparticle-based immunotherapy has emerged as a crucial approach to reverse exhaustion. Here, we have compiled the latest advances in T-cell exhaustion, with a particular focus on the characteristics of exhaustion that can be targeted. Additionally, the emerging nanoparticle-based delivery systems were also reviewed. Moreover, we have discussed, in detail, nanoparticle-based immunotherapies that aim to reverse exhaustion, including targeting immune checkpoint blockades, remodeling the tumor microenvironment, and targeting the metabolism of exhausted T cells, etc. These data could aid in comprehending the immunopathogenesis of exhaustion and accomplishing the objective of preventing and treating chronic diseases or cancer.

Decoding immunogenic cell death from a dendritic cell perspective

Dendritic cells (DCs) are myeloid cells bridging the innate and adaptive immune system. By cross-presenting tumor-associated antigens (TAAs) liberated upon spontaneous or therapy-induced tumor cell death to T cells, DCs occupy a pivotal position in the cancer immunity cycle. Over the last decades, the mechanisms linking cancer cell death to DC maturation, have been the focus of intense research. Growing evidence supports the concept that the mere transfer of TAAs during the process of cell death is insufficient to drive immunogenic DC maturation unless this process is coupled with the release of immunomodulatory signals by dying cancer cells. Malignant cells succumbing to a regulated cell death variant called immunogenic cell death (ICD), foster a proficient interface with DCs, enabling their immunogenic maturation and engagement of adaptive immunity against cancer. This property relies on the ability of ICD to exhibit pathogen-mimicry hallmarks and orchestrate the emission of a spectrum of constitutively present or de novo-induced danger signals, collectively known as damage-associated molecular patterns (DAMPs). In this review, we discuss how DCs perceive and decode danger signals emanating from malignant cells undergoing ICD and provide an outlook of the major signaling and functional consequences of this interaction for DCs and antitumor immunity.

RNA-Based Therapeutic Technology

RNA-based therapy has been an expanding area of clinical research since the COVID-19 outbreak. Often, its comparison has been made to DNA-based gene therapy, such as adeno-associated virus- and lentivirus-mediated therapy. These DNA-based therapies show persistent expression, with maximized therapeutic efficacy. However, accumulating data indicate that proper control of gene expression is occasionally required. For example, in cancer immunotherapy, cytokine response syndrome is detrimental for host animals, while excess activation of the immune system induces supraphysiological cytokines. RNA-based therapy seems to be a rather mild therapy, and it has room to fit unmet medical needs, whereas current DNA-based therapy has unclear issues. This review focused on RNA-based therapy for cancer immunotherapy, hematopoietic disorders, and inherited disorders, which have received attention for possible clinical applications.