Sustained Drug Release From Liposomes for the Remodeling of Systemic Immune Homeostasis and the Tumor Microenvironment

Navigating the Clinical Landscape of Liposomal Therapeutics in Cancer Treatment

Liposome-based targeted drug delivery systems represent a significant advancement in pharmaceutical science, offering distinct advantages that enhance the efficacy and safety of various therapies. These versatile carriers can encapsulate both hydrophilic and hydrophobic drugs, making them particularly valuable in clinical settings. This review explores the critical role of liposomal formulations in improving drug pharmacokinetics and minimizing side effects, especially in oncology, where targeted delivery to tumor cells is essential. Outlining the properties of different types of liposomes, we focus on the effects of these properties on the liposomes' targeting and drug release capabilities through innovative surface modifications and describe the most common methods of liposome preparation and characterization. Furthermore, this review provides an in-depth analysis of the properties and composition of liposomal-based nanocarriers, with a unique focus on ongoing clinical trials and recently approved therapies. It offers a comprehensive overview of the latest advancements in pre-clinical research and highlights the critical progress in clinical development, offering insights into the clinical impact and regulatory approvals. Ultimately, this review underscores the transformative potential of liposomal nanocarriers in modern therapeutics, suggesting avenues for future innovations and clinical breakthroughs.

Applications of liposomes and lipid nanoparticles in cancer therapy: current advances and prospects

Liposomes and lipid nanoparticles are common lipid-based drug delivery systems and play important roles in cancer treatment and vaccine manufacture. Although significant progress has been made with these lipid-based nanocarriers in recent years, efficient clinical translation of active targeted liposomal nanocarriers remains extremely challenging. In this review, we focus on targeted liposomes, stimuli-responsive strategy and combined therapy in cancer treatment. We also summarize advances of liposome and lipid nanoparticle applications in nucleic acid delivery and tumor vaccination. In addition, we discuss limitations and challenges in the clinical translation of these lipid nanomaterials and make recommendations for the future research in cancer therapy.

All-trans retinoic acid in hematologic disorders: not just acute promyelocytic leukemia

All-trans retinoic acid (ATRA) plays a role in tissue development, neural function, reproduction, vision, cell growth and differentiation, tumor immunity, and apoptosis. ATRA can act by inducing autophagic signaling, angiogenesis, cell differentiation, apoptosis, and immune function. In the blood system ATRA was first used with great success in acute promyelocytic leukemia (APL), where ATRA differentiated leukemia cells into mature granulocytes. ATRA can play a role not only in APL, but may also play a role in other hematologic diseases such as immune thrombocytopenia (ITP), myelodysplastic syndromes (MDS), non-APL acute myeloid leukemia (AML), aplastic anemia (AA), multiple myeloma (MM), etc., especially by regulating mesenchymal stem cells and regulatory T cells for the treatment of ITP. ATRA can also increase the expression of CD38 expressed by tumor cells, thus improving the efficacy of daratumumab and CD38-CART. In this review, we focus on the mechanism of action of ATRA, its role in various hematologic diseases, drug combinations, and ongoing clinical trials.

Retinoic acid-releasing scaffold based on chitosan hydrogel and testis decellular plates

Introduction

The use of releasing scaffolds is promising for testes tissue engineering. Chitosan (CS) is a natural biopolymer extensively used as a delivery system. The decellularized testis provides a structure resembling natural extracellular matrix (ECM). All-trans retinoic acid (atRA) is an important factor for spermatogonia differentiation, meiosis completion, and mature sperm release. In this study, thermosensitive CS/βGP hydrogel was served as a novel atRA-releasing support for testis decellular plates (TDPs).

Methods

The CS/βGP hydrogel was evaluated for gelation time, morphology, wettability, cytocompatibility, and atRA-releasing behavior. Mouse testes were treated with 1% SDS and evaluated for decellularization efficacy through morphological assessments, DNA content assays, and DAPI staining. TDPs were obtained from the decellularized testes and placed on an atRA-releasing CS/βGP hydrogel support.

Results

The CS/βGP hydrogels were prepared with different formulations. It was found that increasing the βGP concentration significantly decreased the gelation time. The addition of atRA did not considerably affect the hydrophilicity of hydrogel. The in vitro release studies showed a sustained atRA release behavior, although an initial low burst release was recorded. Also, increasing the amount of atRA led to a decrease in the rate of drug release. The decellularization procedure successfully removed cells while preserving the ECM. The atRA-releasing CS-TDP scaffold was found to be non-toxic with good biocompatibility.

Conclusion

Results showed that the novel atRA-releasing CS-TDP scaffold can sustainably deliver atRA to the culture system and create a cytocompatible environment for testicular cells. Therefore, this scaffold may be useful in developing new tissue engineering approaches for various types of male infertility diseases.

MDSC-targeted liposomal all-trans retinoic acid suppresses mMdscs and improves immunotherapy in HBV infection

BACKGROUND

Myeloid-derived suppressor cells (MDSCs) are evolving as a prominent determinant in cancer occurrence and development and are functionally found to suppress T cells in cancer. Not much research is done regarding its involvement in viral infections. This research was designed to investigate the role of MDSCs in hepatitis B virus (HBV) infection and how targeting these cells with our novel all-trans retinoic acid encapsulated liposomal formulation could improve immunotherapy in C57BL/6 mice.

METHODS

Ten micrograms (10 μg) of plasmid adeno-associated virus (pAAV/HBV 1.2, genotype A) was injected hydrodynamically via the tail vein of C57BL/6 mice. An all-trans retinoic acid encapsulated liposomal formulation (L-ATRA) with sustained release properties was used in combination with tenofovir disoproxil fumarate (TDF), a nucleotide analog reverse transcriptase inhibitor (nRTI) to treat the HBV infection. The L-ATRA formulation was given at a dose of 5 mg/kg intravenously (IV) twice a week. The TDF was given orally at 30 mg/kg daily.

RESULTS

Our results revealed that L-ATRA suppresses MDSCs in HBV infected mice and enhanced T-cell proliferation in vitro. In vivo studies showed higher and improved immunotherapeutic effect in mice that received L-ATRA and TDF concurrently in comparison with the groups that received monotherapy. Lower HBV DNA copies, lower concentrations of HBsAg and HBeAg, lower levels of ALT and AST and less liver damage were seen in the mice that received the combination therapy of L-ATRA + TDF.

CONCLUSIONS

In effect, targeting MDSCs with the combination of L-ATRA and TDF effectively reduced mMDSC and improved immunotherapy in the HBV infected mice. Targeting MDSCs could provide a breakthrough in the fight against hepatitis B virus infection.

Radiation-induced tumor immune microenvironments and potential targets for combination therapy

As one of the four major means of cancer treatment including surgery, radiotherapy (RT), chemotherapy, immunotherapy, RT can be applied to various cancers as both a radical cancer treatment and an adjuvant treatment before or after surgery. Although RT is an important modality for cancer treatment, the consequential changes caused by RT in the tumor microenvironment (TME) have not yet been fully elucidated. RT-induced damage to cancer cells leads to different outcomes, such as survival, senescence, or death. During RT, alterations in signaling pathways result in changes in the local immune microenvironment. However, some immune cells are immunosuppressive or transform into immunosuppressive phenotypes under specific conditions, leading to the development of radioresistance. Patients who are radioresistant respond poorly to RT and may experience cancer progression. Given that the emergence of radioresistance is inevitable, new radiosensitization treatments are urgently needed. In this review, we discuss the changes in irradiated cancer cells and immune cells in the TME under different RT regimens and describe existing and potential molecules that could be targeted to improve the therapeutic effects of RT. Overall, this review highlights the possibilities of synergistic therapy by building on existing research.

The prognostic value and therapeutic targeting of myeloid-derived suppressor cells in hematological cancers

The success of immunotherapeutic approaches in hematological cancers is partially hampered by the presence of an immunosuppressive microenvironment. Myeloid-derived suppressor cells (MDSC) are key components of this suppressive environment and are frequently associated with tumor cell survival and drug resistance. Based on their morphology and phenotype, MDSC are commonly subdivided into polymorphonuclear MDSC (PMN-MDSC or G-MDSC) and monocytic MDSC (M-MDSC), both characterized by their immunosuppressive function. The phenotype, function and prognostic value of MDSC in hematological cancers has been intensively studied; however, the therapeutic targeting of this cell population remains challenging and needs further investigation. In this review, we will summarize the prognostic value of MDSC and the different attempts to target MDSC (or subtypes of MDSC) in hematological cancers. We will discuss the benefits, challenges and opportunities of using MDSC-targeting approaches, aiming to enhance anti-tumor immune responses of currently used cellular and non-cellular immunotherapies.