Kun Cheng

Purpose The expression of CD24 is significantly higher in triple-negative breast cancer (TNBC) compared to estrogen receptor and progesterone receptor-positive (ER⁺ PR⁺) breast cancer and normal breast tissue. CD24 overexpression is associated with tumorigenesis, metastasis, and drug resistance in TNBC. Moreover, CD24 functions as a “don’t eat me” signal and disrupts macrophages-mediated phagocytosis of cancer cells. We, therefore, aim to investigate the therapeutic potential of downregulating CD24 in TNBC cells. Methods We designed four CD24 siRNAs and evaluated their silencing efficiency and biological activity in TNBC cells using different methods. We also examined the impact of CD24 silencing on doxorubicin resistance and macrophage-mediated phagocytosis of TNBC cells. Results We have identified a CD24 siRNA that exhibits potent silencing activity in TNBC cells, effectively inhibiting their proliferation, migration, and invasion. CD24 silencing also induces apoptosis of TNBC cells and arrests the cell cycle in the S phase. Moreover, silencing CD24 enhances the sensitivity of TNBC cells to doxorubicin and increases macrophage-mediated phagocytosis of TNBC cells. Conclusions Targeting CD24 with siRNAs is a promising therapeutic strategy for TNBC and other cancers characterized by CD24 overexpression.

Polymeric microneedle patches represent a promising noninvasive platform for the transdermal delivery of peptide and protein therapeutics, and FDA-approved polymers are widely used for this purpose. However, maintaining peptide and protein stability during microneedle fabrication remains a significant challenge. Conventional strategies involve encapsulating within polymer nanoparticles/microparticles, or codissolving them with polymers in organic solvents before microneedle fabrication. These approaches are time-consuming and often lead to low loading efficiency and drug loss. In this study, we developed a novel direct emulsion-based encapsulation strategy that integrates peptides within the PLGA matrix during microneedle formation. This approach generates a uniform water-in-oil (W/O) emulsion that ensures homogeneous peptide dispersion while minimizing interfacial stress, eliminating the need for multistep spraying or postloading processes. The optimized PLGA-based microneedles exhibited uniform geometry, high drug-loading capacity, and strong mechanical integrity suitable for skin penetration. The encapsulated peptide maintains its biological activity after fabrication and during storage, confirming excellent peptide stability. In vivo studies demonstrated successful skin insertion and sustained peptide release for up to 72 h, supporting the potential of this platform for prolonged transdermal peptide delivery. Overall, this work presents a scalable, biocompatible, and solvent-safe microneedle fabrication strategy that preserves peptide functionality while enabling controlled drug release, making it a promising strategy for transdermal peptide therapeutics.

The PD-1/PD-L1 pathway is one of the most effective immune checkpoint pathways utilized for cancer immunotherapy. Despite the success of anti-PD-1/PD-L1 mAbs, there is growing interest in developing low molecular weight anti-PD-1/PD-1 agents, such as peptides, because of their improved tumor penetration. We recently developed a small anti-PD-L1 peptide and demonstrated its promising anti-tumor activity. In this study, we investigate multivalency as a strategy to increase the binding avidity and blocking efficiency of the anti-PD-L1 peptide. Multivalent peptide inhibitors are designed with multiple copies of a peptide inhibitor in a single molecule. We synthesized peptides with different valences and examined their activity. We also investigated how spacer length affects the activity of these multivalent peptides. Using this strategy, we developed a multivalent peptide that demonstrated approximately 40 times higher blocking efficiency and improved stability compared to the original peptide. Increasing the valency enhanced the peptide's specificity, which is essential for minimizing side effects. Multivalency approach represents a promising platform for improving the efficacy of peptide-based checkpoint inhibitors.

Introduction: The tumor microenvironment (TME) of pancreatic cancer is highly immunosuppressive and characterized by a large number of cancer-associated fibroblasts, myeloid-derived suppressor cells, and regulatory T cells. Stimulator of interferon genes (STING) is an endoplasmic reticulum receptor that plays a critical role in immunity. STING agonists have demonstrated the ability to inflame the TME, reduce tumor burden, and confer anti-tumor activity in mouse models. 2’ 3’ cyclic guanosine monophosphate adenosine monophosphate (2’ 3’-cGAMP) is a high-affinity endogenous ligand of STING. However, delivering cGAMP to antigen-presenting cells and tumor cells within the cytosol remains challenging due to membrane impermeability and poor stability. Methods: In this study, we encapsulated 2’ 3’-cGAMP in a lipid nanoparticle (cGAMP-LNP) designed for efficient cellular delivery. We assessed the properties of the nanoparticles using a series of in-vitro studies designed to evaluate their cellular uptake, cytosolic release, and minimal cytotoxicity. Furthermore, we examined the nanoparticle’s anti-tumor effect in a syngeneic mouse model of pancreatic cancer. Results: The lipid platform significantly increased the cellular uptake of 2’ 3’-cGAMP. cGAMP-LNP exhibited promising antitumor activity in the syngeneic mouse model of pancreatic cancer. Discussion: The LNP platform shows promise for delivering exogenous 2’ 3’-cGAMP or its derivatives in cancer therapy.

Cancer immunotherapy targeting adaptive immune cells has been attracting considerable interest due to its great success in treating multiple cancers. Recently, there is also increasing interest in agents that can stimulate innate immune cell activities. Immune checkpoint inhibitors targeting innate immune cells can block inhibitory interactions (“don't eat me” signals) between tumor cells and phagocytes. CD47 is a transmembrane protein overexpressed in various cancers and acts as a potent “do not eat me” signal that contributes to the immune evasion of cancer cells. Anti‐CD47 peptides that can bind to CD47 and block its interaction with signal regulatory protein alpha (SIRPα) are discovered using a novel phage display biopanning strategy. Anti‐CD47 peptides enhance the macrophage‐mediated phagocytosis of NCI‐H82 tumor cells in vitro. Unlike anti‐CD47 antibodies, these peptides do not induce the agglutination of red blood cells. Moreover, anti‐CD47 peptides exhibit high specificity for MC‐38 cancer cells expressing CD47. CMP‐22 peptide show the ability to increase the antitumor activity of doxorubicin and extends the survival of CT26 tumor‐bearing mice. The discovered anti‐CD47 peptides can be considered potential candidates for cancer immunotherapy by blocking the CD47/SIRPα interaction, especially in combination with chemotherapy, to elicit synergistic effects.

Although alcohol is a well-known causal factor associated with liver diseases, challenges remain in inducing liver fibrosis in experimental rodent models. These challenges include rodents’ natural aversion to high concentrations of alcohol, rapid alcohol metabolism, the need for a prolonged duration of alcohol administration, and technical difficulties. Therefore, it is crucial to establish an experimental model that can replicate the features of alcoholic liver fibrosis. The objective of this study was to develop a feasible rat model of alcoholic liver fibrosis that emulates human drinking patterns and combines low-dose chemicals within a relatively short time frame. We successfully developed an 8-week rat model of alcoholic liver fibrosis that mimics chronic and heavy drinking patterns. Rats were fed with a control liquid diet, an alcohol liquid diet, or alcohol liquid diet combined with multiple binges via oral gavage. To accelerate the progression of alcoholic liver fibrosis, we introduced low-dose carbon tetrachloride (CCl₄) through intraperitoneal injection. This model allows researchers to efficiently evaluate potential therapeutics in preclinical studies of alcoholic liver fibrosis within a reasonable time frame.

Sulfur mustard (SM) is a highly toxic chemical agent that causes severe tissue damage, particularly to the eyes, lungs, and skin. Despite advances in treatment, there is a need for more effective therapies for SM-induced tissue injury. Stem cell and exosome therapies are emerging as promising approaches for tissue repair and regeneration. Stem cells can differentiate into multiple cell types and promote tissue regeneration, while exosomes are small vesicles that can deliver therapeutic cargo to target cells. Several preclinical studies demonstrated the potential of stem cell, exosome, or combination therapy for various tissue injury, showing improvements in tissue repairing, inflammation, and fibrosis. However, there are also challenges associated with these therapies, such as the requirement for standardized methods for exosome isolation and characterization, the long-term safety and efficacy and reduced SM-induced tissue injury of these therapies. Stem cell or exosome therapy was used for SM-induced eye and lung injury. Despite the limited data on the use for SM-induced skin injury, this therapy is a promising area of research and may offer new treatment options in the future. In this review, we focused on optimizing these therapies, evaluating their safety and efficacy, and comparing their efficacy to other emerging therapeutic approaches potentially for SM-induced tissue injury in the eye, lung, and skin.