Albumin-hitchhiking: Fostering the pharmacokinetics and anticancer therapeutics

FAP-targeted delivery of radioiodinated probes: A progressive albumin-driven strategy for tumor theranostics

Fibroblasts activated protein (FAP) appears to be a promising target for tumor theranostics. However, the development of radioiodinated probes for FAP has been slow. In this study, a progressive abumin-driven strategy was adopted to improve the FAP-targeted delivery of radioiodinated probes for tumor theranostics. A series of FAP-targeted probes (namely [131I]IPB-FAPI, [131I]IPB-FAPI-A1, [131I]IPB-FAPI-A3, [131I]FSDD3I) were synthesized by incorporating an albumin-binding moiety (4-(p-iodophenyl)butyric acid, 4-IPBA) labeled with radioiodine. The specificity and binding characteristics of the radiotracers to FAP and human serum albumin (HSA) were confirmed. SPECT imaging results showed that the [131I]FSDD3I had more prominent tumor retention property and superior target-to-nontarget ratio, which were consistent with the biodistribution results. As expected, the FAP-targeted therapy with 11.1 MBq [131I]FSDD3I significantly inhibited tumor growth. In conclusion, this proof-of-concept study employed a progressive design strategy to enhance pharmacokinetics of radioiodinated FAP-targeted probes. Among these radioiodinated FAPI probes, 131I-labeled FSDD3I ([131I]FSDD3I) emerged as a standout candidate with superior competitive advantages for application in radioiodine-guided internal irradiation therapy.

Combating Breast Cancer-associated Metastasis using Paclitaxel and Tranilast-loaded Human Serum Albumin Nanoparticles

OBJECTIVE

The objective of the current study is to combat breast cancer-associated metastasis using paclitaxel (PTX) and tranilast (TRA)-loaded human serum albumin (HAS) Nanoparticles.

SIGNIFICANCE

This combinatorial therapy using microtubule stabilizing agent PTX, along with TGFβ inhibitor TRA.TRA may offer an improved therapeutic effect in breast cancer by inhibiting cell proliferation and metastasis.

METHOD

Inspired by the remarkable anticancer properties of both drugs, they were encapsulated into HSA nanoparticles to enhance tumor site-specific drug accumulation and ensure sustained release over a prolonged period. The HSA nanoparticles were fabricated using the desolvation method and optimized using a Box-Behnken design (BBD) with a three-level, two-factor approach. Further, these nanoparticles were characterized using TEM, FTIR, XRD, and particle size. In vitro experiments were conducted using the MDA-MB-231 cell line, employing cell viability, cellular uptake, nuclear staining, scratch assay, and cell cycle analysis.

KEY FINDINGS

In vitro release kinetics reveal sustained PTX and TRA release from HSA nanoparticles. Wound healing assay depicted improved anti-migratory activity of PTX-TRA-NPs (30nM-75μM). Furthermore, the novel combination treatment caused G2/M phase cell cycle arrest, as indicated by cell cycle analysis.

CONCLUSION

HSA nanoparticles enhance the delivery and accumulation of hydrophobic drugs (PTX and TRA) in breast cancer cells, offering improved therapeutic outcomes. This combinatorial strategy permits further preclinical investigation for synergistic breast cancer management.

Albumin-based nanoparticles: a potential and emerging oral drug delivery system

OBJECTIVE

The purpose of this review is to elaborate current development and challenges of oral albumin nanoparticles, and realize their clinical application.

SIGNIFICANCE

Albumin is an emerging protein nanocarrier with a high degree of versatility, safety, stability, modifiability. These characteristics endow albumin nanoparticles with considerable attention and unique roles in drug delivery. However, most albumin nanoparticles are administered intravenously instead of orally, although oral administration is the most popular and common drug delivery route. Oral administration of albumin nanoparticles is their inevitable tendency, but researches referred to this area are still in infancy.

METHODS AND RESULTS

Given that, firstly, the basic properties of albumin nanoparticles, like preparation methods, drug loading strategies, targeted drug delivery, and clinical application were simply discussed to provide design guide for their oral administration. Subsequently, the functions and challenges of albumin nanoparticles in oral drug delivery, and strategies to overcome the barriers were highlighted. Finally, aiming to realize their clinical potentials, the possible future trends of orally administrated albumin nanoparticles were also elaborated.

CONCLUSIONS

In this review, albumin nanoparticles were comprehensively introduced, especially their functions and challenges in oral drug delivery, aiming to guide their design and development.

Precision-Guided Stealth Missiles in Biomedicine: Biological Carrier-Mediated Nanomedicine Hitchhiking Strategy

Nanodrug delivery systems (NDDS) have demonstrated broad application prospects in disease treatment, prevention, and diagnosis due to several advantages, including functionalization capability, high drug-loading capacity, drug stability protection, and the enhanced permeability and retention (EPR) effect. However, their clinical translation still faces multiple challenges, including rapid clearance by the reticuloendothelial system (RES), poor targeting specificity, and insufficient efficiency in crossing biological barriers. To address these limitations, researchers have developed the biological carrier-mediated nanomedicine hitchhiking strategy (BCM-NHS), which leverages circulating cells, proteins, or bacteria as natural "mobile carriers" to enhance drug delivery. This approach enables nanocarriers to inherit the intrinsic biological properties, endowing them with immune evasion, prolonged circulation, dynamic targeting, biocompatibility, biodegradability, and naturally optimized biological interfaces. Here, a systematic overview of the BCM-NHS is provided. First, the review delves into the methods of nanoparticles (NPs) binding and immobilization, encompassing both the surface-attachment-mediated "backpack" strategy and the encapsulation-based "Trojan horse" strategy. Second, the classification of biological carriers, including both cell-based and non-cell-based carriers, is elucidated. Third, the physical properties and release mechanisms of these nanomaterials are thoroughly described. Finally, the latest applications of BCM-NHS in therapeutic and diagnostic contexts across various disease models including tumor, ischemic stroke, and pneumonia are highlighted.

Unravelling the role of tumor microenvironment responsive nanobiomaterials in spatiotemporal controlled drug delivery for lung cancer therapy

Design and development of efficient drug delivery technologies that impart site-specificity is the need of the hour for the effective treatment of lung cancer. The emergence of materials science and nanotechnology partially helped drug delivery scientists to achieve this objective. Various stimuli-responsive materials that undergo degradation at the pathological tumor microenvironment (TME) have been developed and explored for drug delivery applications using nanotechnological approaches. Nanoparticles (NPs), owing to their small size and high surface area to volume ratio, demonstrated enhanced cellular internalization, permeation, and retention at the tumor site. Such passive accumulation of stimuli-responsive materials helped to achieve spatiotemporally controlled and targeted drug delivery within the tumors. In this review, we discussed various stimuli-physical (interstitial pressure, temperature, and stiffness), chemical (pH, hypoxia, oxidative stress, and redox state), and biological (receptor expression, efflux transporters, immune cells, and their receptors or ligands)-that are characteristic to the TME. We mentioned an array of biomaterials-based nanoparticulate delivery systems that respond to these stimuli and control drug release at the TME. Further, we discussed nanoparticle-based combinatorial drug delivery strategies. Finally, we presented our perspectives on challenges related to scale-up, clinical translation, and regulatory approvals.

Amelioration of breast cancer therapies through normalization of tumor vessels and microenvironment: paradigm shift to improve drug perfusion and nanocarrier permeation

Breast cancer (BC) is the most commonly diagnosed cancer among women. Chemo-, immune- and photothermal therapies are employed to manage BC. However, the tumor microenvironment (TME) prevents free drugs and nanocarriers (NCs) from entering the tumor premises. Formulation scientists rely on enhanced permeation and retention (EPR) to extravasate NCs in the TME. However, recent research has demonstrated the inconsistent nature of EPR among different patients and tumor types. In addition, angiogenesis, high intra-tumor fluid pressure, desmoplasia, and high cell and extracellular matrix density resist the accumulation of NCs in the TME. In this review, we discuss TME normalization as an approach to improve the penetration of drugs and NCSs in the tumor premises. Strategies such as normalization of tumor vessels, reversal of hypoxia, alleviation of high intra-tumor pressure, and infiltration of lymphocytes for the reversal of therapy failure have been discussed in this manuscript. Strategies to promote the infiltration of anticancer immune cells in the TME after vascular normalization have been discussed. Studies strategizing time points to administer TME-normalizing agents are highlighted. Mechanistic pathways controlling the angiogenesis and normalization processes are discussed along with the studies. This review will provide greater tumor-targeting insights to the formulation scientists.

Quality by design empowered preparation of itraconazole albumin nanoparticles for prostate cancer

The current advent explores the potential of itraconazole (ITR) in prostate cancer (PCa), by its incorporation into albumin nanoparticles (NP). ITR as a repurposed moiety has displayed tremendous potential in various cancers. However, poor aqueous solubility poses hurdles towards its clinical translation. Amorphisation of ITR was observed post-incorporation within NP matrix which could prevent its precipitation in aqueous media. ITR NP was developed using quality by design and multivariate analysis and evaluated for cellular uptake, cell proliferation inhibition and the mechanism of PCa cell inhibition. Time and concentration-dependent serum stability and hemolytic potential revealed safety of ITR NP. Morphological changes and nuclear staining studies revealed the efficacy of ITR and ITR NP in promoting growth inhibition of PC-3 cells. Superior qualitative and quantitative uptake, reactive oxygen species (ROS) and mitochondrial impairment for ITR NP in comparison with ITR and control group was observed. Cell cycle study revealed remarkable G2/M phase inhibition in PC-3 cells. ITR NP demonstrated superior anticancer potential in 3D tumoroids mimicking the micro-metastatic lesions compared to control and ITR. Hence, ITR NP can be a favorable alternative therapeutic alternative in PCa.

Despicable role of epithelial-mesenchymal transition in breast cancer metastasis: Exhibiting de novo restorative regimens

Breast cancer (BC) is the most prevalent cancer in women globally. Anti-cancer advancements have enabled the killing of BC cells through various therapies; however, cancer relapse is still a major limitation and decreases patient survival and quality of life. Epithelial-to-mesenchymal transition (EMT) is responsible for tumor relapse in several cancers. This highly regulated event causes phenotypic, genetic, and epigenetic changes in the tumor microenvironment (TME). This review summarizes the recent advancements regarding EMT using de-differentiation and partial EMT theories. We extensively review the mechanistic pathways, TME components, and various anti-cancer adjuvant and neo-adjuvant therapies responsible for triggering EMT in BC tumors. Information regarding essential clinical studies and trials is also discussed. Furthermore, we also highlight the recent strategies targeting various EMT pathways. This review provides a holistic picture of BC biology, molecular pathways, and recent advances in therapeutic strategies.

Conjugated Human Serum Albumin/Gold-Silica Nanoparticles as Multifunctional Carrier of a Chemotherapeutic Drug

We report the design and development of a novel multifunctional nanostructure, RB-AuSiO2_HSA-DOX, where tri-modal cancer treatment strategies-photothermal therapy (PTT), photodynamic therapy (PDT), chemotherapy-luminescent properties and targeting are integrated into the same scaffold. It consists of a gold core with optical and thermo-plasmonic properties and is covered by a silica shell entrapping a well-known photosensitizer and luminophore, Rose Bengal (RB). The nanoparticle surface was decorated with Human Serum Albumin (HSA) through a covalent conjugation to confer its targeting abilities and as a carrier of Doxorubicin (DOX), one of the most effective anticancer drugs in clinical chemotherapy. The obtained nanostructure was fully characterized through transmission electron microscopy (TEM), dynamic light scattering (DLS) and UV-visible spectroscopy, with a homogeneous and spherical shape, an average diameter of about 60 nm and negative ζ-potential value Singlet oxygen generation and photothermal properties were explored under green light irradiation. The interaction between DOX-HSA anchored on the nanoplatform was investigated by fluorescence spectroscopy and compared to that of DOX-HSA, pointing out different accessibility of the drug molecules to the HSA binding sites, whether the protein is free or bound to the nanoparticle surface. To the best of our knowledge, there are no studies comparing a drug-HSA interaction with that of the same protein anchored to nanoparticles. Furthermore, the uptake of RB-AuSiO2_HSA-DOX into MDA-MB-231 mammary cells was assessed by confocal imaging, highlighting-at early time of incubation and as demonstrated by the increased DOX luminescence displayed within cells-a better internalization of the carried anticancer drug compared to the free one, making the obtained nanostructure a suitable and promising platform for an anticancer multimodal approach.

Serum Albumin and Its Trajectory Are Associated With Therapeutic Outcomes in Ulcerative Colitis

BACKGROUND & AIMS

The relationship between serum albumin levels and therapeutic outcomes in ulcerative colitis (UC) has been debated. Additionally, the dynamic changes in albumin levels remain understudied.

METHODS

We conducted a pooled analysis of 5 clinical trials involving 3268 patients with UC. Short- and long-term therapeutic outcomes were assessed at the end of the induction and maintenance phases. Multivariate logistic regression and random effects models were used to pool the predictive effects of albumin levels. The dynamic trajectory of albumin was fitted using latent class growth mixed models.

RESULTS

Baseline and week-2 albumin were independent predictors of short-term outcomes, with pooled adjusted odds ratios (aORs) of 1.07 (95% confidence interval [CI],1.05-1.09) and 1.11 (95% CI, 1.08-1.15) per 1 g/L increase for clinical response, respectively. Higher post-induction albumin levels predicted better long-term outcomes, including clinical (aOR, 1.16; 95% CI, 1.12-1.21), endoscopic (aOR, 1.13; 95% CI, 1.10-1.16), and histologic remission (aOR, 1.11; 95% CI, 1.03-1.18). Furthermore, there are 3 classes of albumin trajectories: sustained medium-to-high, rapidly ascending, and poor response. Compared with the sustained medium-to-high class, patients in the poor response class had a lower probability of long-term endoscopic remission (aOR, 0.35; 95% CI, 0.23-0.50; P < .001), whereas no significant difference was observed between the rapidly ascending class and the sustained medium-to-high class.

CONCLUSION

Higher albumin levels were associated with better therapeutic outcomes in patients with UC. However, patients with low but rapidly ascending albumin levels would achieve outcomes comparable to those with medium-to-high levels of albumin.

Gallium-68 Labeled Positron Emission Computed Tomography Tracer Targeting Glypican-3 with High Contrast for Hepatocellular Carcinoma Imaging

Hepatocellular carcinoma (HCC) represents the predominant form of primary liver cancer, yet early, precise, and noninvasive detection continues to pose a considerable clinical challenge. Glypican-3 (GPC3), a membrane-bound proteoglycan, is markedly overexpressed in most HCC cases, while exhibiting low expression in normal and hepatitis-affected liver tissues. Given its crucial role in malignant transformation and tumor progression, GPC3 emerges as a compelling target for imaging. In this study, we developed and evaluated 2 68Ga-labeled GPC3-targeted positron emission tomography (PET) probes, each incorporating either polyethylene glycol (PEG) or 4-(p-methylphenyl)butanoic acid (an albumin-binding moiety). Comparative analyses revealed that 68Ga-ALB-GBP, which includes the albumin-binding moiety, exhibited superior in vivo stability, enhanced tumor uptake, and an improved tumor-to-liver ratio relative to 68Ga-PEG2-GBP in subcutaneous HCC mouse models. Micro-PET/computed tomography imaging of orthotopic liver cancer with 68Ga-ALB-GBP demonstrated a tumor-to-liver ratio of 2.29 ± 0.13 and a tumor-to-muscle ratio of 13.03 ± 1.63 at 3 h postinjection, outperforming the performance of the clinically used 18F-fluorodeoxyglucose PET imaging. These findings suggest that 68Ga-ALB-GBP is a promising diagnostic tool for HCC and a strong candidate for clinical translation with potential utility in both diagnostic and therapeutic settings. Moreover, the incorporation of an albumin-binding moiety into PET tracers significantly extends blood circulation time, thereby enhancing bioavailability and facilitating high-contrast PET imaging.

SON-1010: an albumin-binding IL-12 fusion protein that improves cytokine half-life, targets tumors, and enhances therapeutic efficacy

Background

Cytokines have been promising cancer immunotherapeutics for decades, yet only two are licensed to date. Interleukin-12 (IL-12) is a potent regulator of cell-mediated immunity that activates NK cells and interferon-γ (IFNγ) production. It plays a central role in multiple pathways that can enhance cancer cell death and modify the tumor microenvironment (TME). Attempts to dose rIL-12 were initially successful but IFNγ toxicity in Phase 2 complicated further development in the late 1990s. Since then, better dosing strategies have been developed, but none have achieved the level of cancer control seen in preclinical models. We set out to develop a novel strategy to deliver fully functional IL-12 and other biologics to the TME by binding albumin, taking advantage of its ability to be concentrated and retained in the tumor.

Methods

Single-chain variable fragments (scFv) were identified from a human phage display library that bound human, mouse, and cynomolgus macaque serum albumin, both at physiologic and acidic conditions. These were taken through a series of steps to identify strongly binding molecules that don't interfere with the normal physiology of albumin to bind FcRn, giving it prolonged half-life in serum, along with SPARC/GP60, which allows albumin to target the TME. A final molecule was chosen and a single mutation was made that minimizes the potential for immunogenicity. This fully human albumin-binding (FHAB®) domain was characterized and manufacturing processes were developed to bring the first drug candidate into the clinic.

Results

Once identified, the murine form of mIL12-FHAB was studied preclinically to understand its mechanism of action and biodistribution. It was found to be much more efficient at blocking tumor growth compared to murine IL-12, while stimulating significant IFNγ production with minimal toxicity. SON-1010, which uses the human IL-12 sequence, passed through all of the characterization and required toxicology and is currently being studied in the clinic.

Conclusions

We identified and developed a platform technology with prolonged half-life that can target IL-12 and other immune modulators to the TME. Safety and efficacy are being studied using SON-1010 as monotherapy and in combination with checkpoint blockade strategies.

Albumin-based strategies to effectively prolong the circulation half-life of small immunomodulatory payloads in cancer therapy

Small immunomodulatory payloads (IMMs) such as peptide vaccines and cytokines have the capability to activate and boost the immune response against cancer. However, their clinical use has often been hindered by their poor stability and short circulating half-lives. To enhance the pharmacokinetic properties of small IMMs and promote their trafficking and accumulation in lymphatic and tumor tissues, a large variety of strategies have been developed. One of the most successful relies on the use of serum albumin (SA), the most abundant protein in the circulatory and lymphatic system. Here, we report a comparative analysis of the different covalent and noncovalent SA-based strategies applied so far to improve the efficacy of small IMMs in cancer therapy.

PH-Triggered, Lymph Node Focused Immunodrug Release by Polymeric 2-Propionic-3-Methyl-maleic Anhydrides with Cholesteryl End Groups

Gaining spatial control over innate immune activation is of great relevance during vaccine delivery and anticancer therapy, where one aims at activating immune cells at draining lymphoid tissue while avoiding systemic off-target innate immune activation. Lipid-polymer amphiphiles show high tendency to drain to lymphoid tissue upon local administration. Here, pH-sensitive, cholesteryl end group functionalized polymers as stimuli-responsive carriers are introduced for controlled immunoactivation of draining lymph nodes. Methacrylamide-based monomers bearing pendant 2-propionic-3-methylmaleic anhydride groups are polymerized by Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization using a cholesterol chain-transfer agent (chol-CTA). The amine-reactive anhydrides are conjugated with various amines, however, while primary amines afforded irreversible imides, secondary amines provided pH-responsive conjugates that are released upon acidification. This can be applied to fluorescent dyes for irreversibly carrier labeling or immunostimulatory Toll-like receptor (TLR) 7/8 agonists as cargos for pH-responsive delivery. Hydrophilization of remaining anhydride repeating units with short PEG-chains yielded cholesteryl-polymer amphiphiles that showed efficient cellular uptake and increased drug release at endosomal pH. Moreover, reversibly conjugated TLR 7/8 agonist amphiphiles efficiently drained to lymph nodes and increased the number of effectively maturated antigen-presenting cells after subcutaneous injection in vivo. Consequently, cholesteryl-linked methacrylamide-based polymers with pH-sensitive 2-propionic-3-methylmaleic anhydride side groups provide ideal features for immunodrug delivery.

The Journey of Antibody-Drug Conjugates: Lessons Learned from 40 Years of Development

Antibody-drug conjugates (ADC) represent one of the most rapidly expanding treatment modalities in oncology, with 11 ADCs approved by the FDA and more than 210 currently being tested in clinical trials. Spanning over 40 years, ADC clinical development has enhanced our understanding of the multifaceted mechanisms of action for this class of therapeutics. In this article, we discuss key insights into the toxicity, efficacy, stability, distribution, and fate of ADCs. Furthermore, we highlight ongoing challenges related to their clinical optimization, the development of rational sequencing strategies, and the identification of predictive biomarkers. Significance: The development and utilization of ADCs have allowed for relevant improvements in the prognosis of multiple cancer types. Concomitantly, the rise of ADCs in oncology has produced several challenges, including the prediction of their activity, their utilization in sequence, and minimization of their side effects, that still too often resemble those of the cytotoxic molecule that they carry. In this review, we retrace 40 years of development in the field of ADCs and delve deep into the mechanisms of action of these complex therapeutics and reasons behind the many achievements and failures observed in the field to date.

Synthetic organic materials for targeting immunotherapies to lymph nodes

Immunotherapies have yielded tremendous advances over the last three decades. However even the most promising therapies, for example monoclonal antibodies, require systemic infusion that can limit dosing and lead to off target immunotoxicity. To address such challenges and improve immunotherapy, the field is investing in synthetic biomaterials to target lymph nodes (LNs) - sites of coordinated immune activation and suppression. These synthetic materials allow enhanced targeting, retention, and control over the signals that are required to elicit desired immune processes during immunotherapy. Two broad classes of materials that have been employed for LN targeting include synthetic lipids and polymers. This review will discuss how the chemistries of these materials can be leveraged to improve lymph node targeting of immunotherapies to treat disease. We will also provide commentary on translational barriers to the clinic, an outlook on current therapies that are clinically used, and a forward-looking perspective.

Tailoring biomaterials for vaccine delivery

Biomaterials are substances that can be injected, implanted, or applied to the surface of tissues in biomedical applications and have the ability to interact with biological systems to initiate therapeutic responses. Biomaterial-based vaccine delivery systems possess robust packaging capabilities, enabling sustained and localized drug release at the target site. Throughout the vaccine delivery process, they can contribute to protecting, stabilizing, and guiding the immunogen while also serving as adjuvants to enhance vaccine efficacy. In this article, we provide a comprehensive review of the contributions of biomaterials to the advancement of vaccine development. We begin by categorizing biomaterial types and properties, detailing their reprocessing strategies, and exploring several common delivery systems, such as polymeric nanoparticles, lipid nanoparticles, hydrogels, and microneedles. Additionally, we investigated how the physicochemical properties and delivery routes of biomaterials influence immune responses. Notably, we delve into the design considerations of biomaterials as vaccine adjuvants, showcasing their application in vaccine development for cancer, acquired immunodeficiency syndrome, influenza, corona virus disease 2019 (COVID-19), tuberculosis, malaria, and hepatitis B. Throughout this review, we highlight successful instances where biomaterials have enhanced vaccine efficacy and discuss the limitations and future directions of biomaterials in vaccine delivery and immunotherapy. This review aims to offer researchers a comprehensive understanding of the application of biomaterials in vaccine development and stimulate further progress in related fields.

Nano-anticoagulant based on carrier-free low molecular weight heparin and octadecylamine with an albumin shuttling effect

Low-molecular-weight heparin (LMWH), derived from unfractionated heparin (UFH), has enhanced anticoagulant efficacy, long duration of action, and extended half-life. Patients receiving LMWH for preventive therapies would strongly benefit from its long-term effects, however, achieving this is challenging. Here, we design and evaluate a nanoengineered LMWH and octadecylamine conjugate (LMHO) that can act for a long time while maintaining close to 97 ± 3% of LMWH activity via end-specific conjugation of the reducing end of LMWH. LMHO can self-assemble into nanoparticles with an average size of 105 ± 1.7 nm in water without any nanocarrier and can be combined with serum albumin, resulting in a lipid-based albumin shuttling effect. Such molecules can circulate in the bloodstream for 4-5 days. We corroborate the self-assembly capability of LMHO and its interaction with albumin through molecular dynamics (MD) simulations and transmission electron microscopy (TEM) analysis. This innovative approach to carrier-free polysaccharide delivery, enhanced by nanoengineered albumin shuttling, represents a promising platform to address limitations in conventional therapies.

Adjuvants for cancer mRNA vaccines in the era of nanotechnology: strategies, applications, and future directions

Research into mRNA vaccines is advancing rapidly, with proven efficacy against coronavirus disease 2019 and promising therapeutic potential against a variety of solid tumors. Adjuvants, critical components of mRNA vaccines, significantly enhance vaccine effectiveness and are integral to numerous mRNA vaccine formulations. However, the development and selection of adjuvant platforms are still in their nascent stages, and the mechanisms of many adjuvants remain poorly understood. Additionally, the immunostimulatory capabilities of certain novel drug delivery systems (DDS) challenge the traditional definition of adjuvants, suggesting that a revision of this concept is necessary. This review offers a comprehensive exploration of the mechanisms and applications of adjuvants and self-adjuvant DDS. It thoroughly addresses existing issues mentioned above and details three main challenges of immune-related adverse event, unclear mechanisms, and unsatisfactory outcomes in old age group in the design and practical application of cancer mRNA vaccine adjuvants. Ultimately, this review proposes three optimization strategies which consists of exploring the mechanisms of adjuvant, optimizing DDS, and improving route of administration to improve effectiveness and application of adjuvants and self-adjuvant DDS.

Programable Albumin-Hitchhiking Nanobodies Enhance the Delivery of STING Agonists to Potentiate Cancer Immunotherapy

Stimulator of interferon genes (STING) is a promising target for potentiating antitumor immunity, but multiple pharmacological barriers limit the clinical utility, efficacy, and/or safety of STING agonists. Here we describe a modular platform for systemic administration of STING agonists based on nanobodies engineered for in situ hitchhiking of agonist cargo on serum albumin. Using site-selective bioconjugation chemistries to produce molecularly defined products, we found that covalent conjugation of a STING agonist to anti-albumin nanobodies improved pharmacokinetics and increased cargo accumulation in tumor tissue, stimulating innate immune programs that increased the infiltration of activated natural killer cells and T cells, which potently inhibited tumor growth in multiple mouse tumor models. We also demonstrated the programmability of the platform through the recombinant integration of a second nanobody domain that targeted programmed cell death ligand-1 (PD-L1), which further increased cargo delivery to tumor sites while also blocking immunosuppressive PD-1/PD-L1 interactions. This bivalent nanobody carrier for covalently conjugated STING agonists stimulated robust antigen-specific T cell responses and long-lasting immunological memory, conferred enhanced therapeutic efficacy, and was effective as a neoadjuvant treatment for improving responses to adoptive T cell transfer therapy. Albumin-hitchhiking nanobodies thus offer an enabling, multimodal, and programmable platform for systemic delivery of STING agonists with potential to augment responses to multiple immunotherapeutic modalities.

Half-life extension of single-domain antibody-drug conjugates by albumin binding moiety enhances antitumor efficacy

Single-domain antibody-drug conjugates (sdADCs) have been proven to have deeper solid tumor penetration and intratumor accumulation capabilities due to their smaller size compared with traditional IgG format ADCs. However, one of the key challenges for improving clinical outcomes of sdADCs is their abbreviated in vivo half-life. In this study, we innovatively fused an antihuman serum albumin (αHSA) nanobody to a sdADCs targeting oncofetal antigen 5T4, conferring serum albumin binding to enhance the pharmacokinetic profiles of sdADCs. The fusion protein was conjugated with monomethyl auristatin E (MMAE) at s224c site mutation. The conjugate exhibited potent cytotoxicity against various tumor cells. Compared with the nonalbumin-binding counterparts, the conjugate exhibited a 10-fold extended half-life in wild-type mice and fivefold prolonged serum half-life in BxPC-3 xenograft tumor models as well as enhanced tumor accumulation and retention in mice. Consequently, n501-αHSA-MMAE showed potent antitumor effects, which were comparable to n501-MMAE in pancreatic cancer BxPC-3 xenograft tumor models; however, in human ovarian teratoma PA-1 xenograft tumor models, n501-αHSA-MMAE significantly improved antitumor efficacy. Moreover, the conjugate showed mitigated hepatotoxicity. In summary, our results suggested that fusion to albumin-binding moiety as a viable strategy can enhance the therapeutic potential of sdADCs through optimized pharmacokinetics.

A Versatile Platform to Generate Prodrugs with Rapid and Precise Albumin Hitchhiking and High Cargo Loading for Tumor-Targeted Chemotherapy

Due to its tumor homing and long serum half-life, albumin is an ideal drug carrier for chemotherapy. For endogenous albumin hitchhiking with high cargo loading, a trimeric albumin-binding domain (ABD), i.e., ABD-Tri is designed by fusing an ABD with high specificity and affinity for albumin to a self-trimerizing domain (Tri) with an additional cysteine residue. ABD-Tri is highly (40 mg L-1) expressed as soluble and trimeric proteins in Escherichia coli (E. coli). Once mixed together, ABD-Tri rapidly and specifically forms a stable complex with albumin under physiological conditions without obviously changing its receptor- and cell-binding and tumor-homing properties. Maleimide-modified prodrugs are highly effectively conjugated to ABD-Tri to produce homogenous ABD-Tri-prodrugs with triple cargo loading under physiological conditions by thiol-maleimide click chemistry. Unlike the maleimide moiety, which can only mediate time- and concentration-dependent albumin binding, ABD-Tri mediated fast (within several minutes) albumin binding of drugs even at extremely low concentrations (µg mL-1). Compared to maleimide-modified prodrugs, ABD-Tri-prodrugs exhibit better tumor homing and greater in vivo antitumor effect, indicating that conjugation of chemical drug to ABD-Tri outperforms maleimide modification for endogenous albumin hitchhiking. The results demonstrate that ABD-Tri may serve as a novel platform to produce albumin-binding prodrugs with high cargo-loading capacity for tumor-targeted chemotherapy.

Anti-osteosarcoma trimodal synergistic therapy using NiFe-LDH and MXene nanocomposite for enhanced biocompatibility and efficacy

Osteosarcoma is usually resistant to immunotherapy and, thus primarily relies on surgical resection and high-dosage chemotherapy. Unfortunately, less invasive or toxic therapies such as photothermal therapy (PTT) and chemodynamic therapy (CDT) generally failed to show satisfactory outcomes. Adequate multimodal therapies with proper safety profiles may provide better solutions for osteosarcoma. Herein, a simple nanocomposite that synergistically combines CDT, PTT, and chemotherapy for osteosarcoma treatment was fabricated. In this composite, small 2D NiFe-LDH flakes were processed into 3D hollow nanospheres via template methods to encapsulate 5-Fluorouracil (5-FU) with high loading capacity. The nanospheres were then adsorbed onto larger 2D Ti3C2 MXene monolayers and finally shielded by bovine serum albumin (BSA) to form 5-FU@NiFe-LDH/Ti3C2/BSA nanoplatforms (5NiTiB). Both in vitro and in vivo data demonstrated that the 5-FU induced chemotherapy, NiFe-LDH driven chemodynamic effects, and MXene-based photothermal killing collectively exhibited a synergistic "all-in-one" anti-tumor effect. 5NiTiB improved tumor suppression rate from <5% by 5-FU alone to ∼80.1%. This nanotherapeutic platform achieved higher therapeutic efficacy with a lower agent dose, thereby minimizing side effects. Moreover, the composite is simple to produce, enabling the fine-tuning of dosages to suit different requirements. Thus, the platform is versatile and efficient, with potential for further development.

Manganese@Albumin Nanocomplex and Its Assembled Nanowire Activate TLR4-Dependent Signaling Cascades of Macrophages

The immunomodulatory effect of divalent manganese cations (Mn2+ ), such as activation of the cGAS-STING pathway or NLRP3 inflammasomes, positions them as adjuvants for cancer immunotherapy. In this study, it is found that trace Mn2+ ions, bound to bovine serum albumin (BSA) to form Mn@BSA nanocomplexes, stimulate pro-inflammatory responses in human- or murine-derived macrophages through TLR4-mediated signaling cascades. Building on this, the assembly of Mn@BSA nanocomplexes to obtain nanowire structures enables stronger and longer-lasting immunostimulation of macrophages by regulating phagocytosis. Furthermore, Mn@BSA nanocomplexes and their nanowires efficiently activate peritoneal macrophages, reprogramme tumor-associated macrophages, and inhibit the growth of melanoma tumors in vivo. They also show better biosafety for potential clinical applications compared to typical TLR4 agonists such as lipopolysaccharides. Accordingly, the findings provide insights into the mechanism of metalloalbumin complexes as potential TLR agonists that activate macrophage polarization and highlight the importance of their nanostructures in regulating macrophage-mediated innate immunity.

Design strategies for enhancing antitumor efficacy through tumor microenvironment exploitation using albumin-based nanosystems: A review

The tumor microenvironment (TME) is a complex and dynamic system that plays a crucial role in regulating cancer progression, treatment response, and the emergence of acquired resistance mechanisms. The TME is usually featured by severe hypoxia, low pH values, high hydrogen peroxide (H2O2) concentrations, and overproduction of glutathione (GSH). The current development of intelligent nanosystems that respond to TME has shown great potential to enhance the efficacy of cancer treatment. As one of the functional macromolecules explored in this field, albumin-based nanocarriers, known for their inherent biocompatibility, serves as a cornerstone for constructing diverse therapeutic platforms. In this paper, we present a comprehensive overview of the latest advancements in the design strategies of albumin nanosystems, aiming to enhance cancer therapy by harnessing various features of solid tumors, including tumor hypoxia, acidic pH, the condensed extracellular matrix (ECM) network, excessive GSH, high glucose levels, and tumor immune microenvironment. Furthermore, we highlight representative designs of albumin-based nanoplatforms by exploiting the TME that enhance a broad range of cancer therapies, such as chemotherapy, phototherapy, radiotherapy, immunotherapy, and other tumor therapies. Finally, we discuss the existing challenges and future prospects in direction of albumin-based nanosystems for the practical applications in advancing enhanced cancer treatments.

A phase 1 trial to determine the maximum tolerated dose and patient-specific dosimetry of [177Lu]Lu-LNC1003 in patients with metastatic castration-resistant prostate cancer

PURPOSE

This translational study aimed to determine the maximum tolerated dose (MTD), safety, dosimetry, and therapeutic efficacy of 177Lu-PSMA-EB-01 (denoted as [177Lu]Lu-LNC1003) in patients with metastatic castration-resistant prostate cancer (mCRPC).

METHODS

A total of 13 patients with mCRPC were recruited in this study. A standard 3 + 3 dose escalation protocol was performed. The following dose levels were ultimately evaluated: 1.11, 1.85, and 2.59 GBq/cycle. Patients received [177Lu]Lu-LNC1003 therapy for up to two cycles at a 6-week interval.

RESULTS

Patients received fractionated doses of [177Lu]Lu-LNC1003 ranging from 1.11 to 2.59 GBq per cycle. Myelosuppression was dose-limiting at 2.59 GBq, and 1.85 GBq was determined to be the MTD. The total-body effective dose for 177Lu-LNC1003 was 0.35 ± 0.05 mSv/MBq. The salivary glands were found to receive the highest estimated radiation dose, which was calculated to be 3.61 ± 2.83 mSv/MBq. The effective doses of kidneys and red bone marrow were 1.88 ± 0.35 and 0.22 ± 0.04 mSv/MBq, respectively. The tumor mean absorbed doses for bone and lymph node metastases were 8.52 and 9.51 mSv/MBq. Following the first treatment cycle, PSA decline was observed in 1 (33.3%), 4 (66.7%), and 2 (50.0%) patients at dose levels 1 (1.11 GBq), 2 (1.85 GBq), and 3 (2.59 GBq), respectively. Compared with the baseline serum PSA value, 1 (33.3%) at dose level 1 and 4 (66.6%) patients at dose level 2, presented a PSA decline after the second treatment cycle.

CONCLUSION

This phase 1 trial revealed that the MTD of [177Lu]Lu-LNC1003 is 1.85 GBq. The treatment with multiple cycles at the dose of 1.11 GBq /cycle and 1.85 GBq /cycle was well tolerated. [177Lu]Lu-LNC1003 has higher tumor effective doses in bone and lymph nodes metastases while the absorbed dose in the red bone marrow should be closely monitored in future treatment studies with higher doses and multiple cycles. The frequency of administration also needs to be further explored to assess the efficacy and side effects of [177Lu]Lu-LNC1003 treatment.

TRIAL REGISTRATION

177Lu-PSMA-EB-01 in patients with metastatic castration-resistant prostate cancer (NCT05613738, Registered 14 November 2022). URL of registry https://classic.

CLINICALTRIALS

gov/ct2/show/NCT05613738.

In situ cellular hitchhiking of nanoparticles for drug delivery

Since the inception of the concept of "magic bullet", nanoparticles have evolved to be one of the most effective carriers in drug delivery. Nanoparticles improve the therapeutic efficacy of drugs offering benefits to treating various diseases. Unlike free drugs which freely diffuse and distribute through the body, nanoparticles protect the body from the drug by reducing non-specific interactions while also improving the drug's pharmacokinetics. Despite acquiring some FDA approvals, further clinical application of nanoparticles is majorly hindered by its limited ability to overcome biological barriers resulting in uncontrolled biodistribution and high clearance. The use of cell-inspired systems has emerged as a promising approach to overcome this challenge as cells are biocompatible and have improved access to tissues and organs. One of such is the hitchhiking of nanoparticles to circulating cells such that they are recognized as 'self' components evading clearance and resulting in site-specific drug delivery. In this review, we discuss the concept of nanoparticle cellular hitchhiking, highlighting its advantages, the principles governing the process and the challenges currently limiting its clinical translation. We also discuss in situ hitchhiking as a tool for overcoming these challenges and the considerations to be taken to guide research efforts in advancing this promising technology.

Lymph node targeting for immunotherapy

Immunotherapy that aims to boost the body's immune responses against pathogens or diseased cells has achieved significant progress for treating different diseases over the past several decades, especially with the success of checkpoint blockades, chimeric antigen receptor T therapy, and cancer vaccines in clinical cancer treatment. Effective immunotherapy necessitates the generation of potent and persistent humoral and T-cell responses, which lies in the ability of modulating and guiding antigen-presenting cells to prime antigen-specific T and B cells in the lymphoid tissues, notably in the lymph nodes proximal to the disease site. To this end, various types of strategies have been developed to facilitate the delivery of immunomodulatory agents to immune cells (e.g. dendritic cells and T cells) in the lymph nodes. Among them, intranodal injection enables the direct exposure of immunomodulators to immune cells in lymph nodes, but is limited by the technical challenge and intrinsic invasiveness. To address, multiple passive and active lymph node-targeting technologies have been developed. In this review, we will provide an overview of different lymph node-targeting technologies developed to date, as well as the mechanism and merits of each approach.

Battle of the milky way: Lymphatic targeted drug delivery for pathogen eradication

Many viruses, bacteria, and parasites rely on the lymphatic system for survival, replication, and dissemination. While conventional anti-infectives can combat infection-causing agents in the bloodstream, they do not reach the lymphatic system to eradicate the pathogens harboured there. This can result in ineffective drug exposure and reduce treatment effectiveness. By developing effective lymphatic delivery strategies for antiviral, antibacterial, and antiparasitic drugs, their systemic pharmacokinetics may be improved, as would their ability to reach their target pathogens within the lymphatics, thereby improving clinical outcomes in a variety of acute and chronic infections with lymphatic involvement (e.g., acquired immunodeficiency syndrome, tuberculosis, and filariasis). Here, we discuss approaches to targeting anti-infective drugs to the intestinal and dermal lymphatics, aiming to eliminate pathogen reservoirs and interfere with their survival and reproduction inside the lymphatic system. These include optimized lipophilic prodrugs and drug delivery systems that promote lymphatic transport after oral and dermal drug intake. For intestinal lymphatic delivery via the chylomicron pathway, molecules should have logP values >5 and long-chain triglyceride solubilities >50 mg/g, and for dermal lymphatic delivery via interstitial lymphatic drainage, nanoparticle formulations with particle size between 10 and 100 nm are generally preferred. Insight from this review may promote new and improved therapeutic solutions for pathogen eradication and combating infective diseases, as lymphatic system involvement in pathogen dissemination and drug resistance has been neglected compared to other pathways leading to treatment failure.

Quality by design endorsed fabrication of Ibrutinib-loaded human serum albumin nanoparticles for the management of leukemia

Ibrutinib (IB), a BCS class II drug suffers from limited aqueous solubility, short half-life and extensive first-pass metabolism. In this project, we aim to recruit the desirable properties of human serum albumin (HSA) as a biocompatible drug carrier to circumvent nanoparticle-associated drawbacks. Quality by design and multivariate analysis was used for the optimization of IB-NPs. Cell culture studies performed on the K562 cell line revealed that the Ibrutinib-loaded HSA NPs demonstrated improved cytotoxicity, drug uptake, and reactive oxygen species generation in the leukemic K562 cells. Cell cycle analysis revealed G2/M phase retention of the leukemia cells. In vitro protein corona and hemolysis studies revealed superior hematological stability compared to the free drug which showed greater than 40 % hemolysis. In vitro drug release studies showed prolonged release profile till 48 h. Pharmacokinetic studies demonstrated a 2.31-fold increase in AUC and an increase in half-life from 0.43 h to 2.887 h with a tremendous reduction in clearance and elimination rate indicating prolonged systemic circulation which is desirable in leukemia. Hence, we conclude that IB-loaded albumin nanoparticles could be a promising approach for the management of leukemia.

Vaccine adjuvants: mechanisms and platforms

Adjuvants are indispensable components of vaccines. Despite being widely used in vaccines, their action mechanisms are not yet clear. With a greater understanding of the mechanisms by which the innate immune response controls the antigen-specific response, the adjuvants' action mechanisms are beginning to be elucidated. Adjuvants can be categorized as immunostimulants and delivery systems. Immunostimulants are danger signal molecules that lead to the maturation and activation of antigen-presenting cells (APCs) by targeting Toll-like receptors (TLRs) and other pattern recognition receptors (PRRs) to promote the production of antigen signals and co-stimulatory signals, which in turn enhance the adaptive immune responses. On the other hand, delivery systems are carrier materials that facilitate antigen presentation by prolonging the bioavailability of the loaded antigens, as well as targeting antigens to lymph nodes or APCs. The adjuvants' action mechanisms are systematically summarized at the beginning of this review. This is followed by an introduction of the mechanisms, properties, and progress of classical vaccine adjuvants. Furthermore, since some of the adjuvants under investigation exhibit greater immune activation potency than classical adjuvants, which could compensate for the deficiencies of classical adjuvants, a summary of the adjuvant platforms under investigation is subsequently presented. Notably, we highlight the different action mechanisms and immunological properties of these adjuvant platforms, which will provide a wide range of options for the rational design of different vaccines. On this basis, this review points out the development prospects of vaccine adjuvants and the problems that should be paid attention to in the future.