Multimodal imaging demonstrates enhanced tumor exposure of PEGylated FUD peptide in breast cancer

Screening Natural Cholesterol Analogs to Assemble Self-Adjuvant Lipid Nanoparticles for Antigens Tagging Guided Therapeutic Tumor Vaccine

The clinical progress of tumor nucleotide vaccines is limited due to insufficient recognition and killing of tumor cells with low antigen expression by cytotoxic T lymphocytes (CTL). Here, natural cholesterol analogs are screened to assemble self-adjuvant lipid nanoparticles (LNPs) for antigens tagging tumor cells and dendritic cells (DC) activation. First, a library of ginsenosides are collected, and then screened according to their anti-tumor immunity. Then, ginsenoside-Rg3 based-LNPs loaded with antigens (Rg3-LNPs) are identified as the optimal formulation by investigating the physicochemical and biological properties. Finally, Rg3-LNPs and granulocyte-macrophage colony-stimulating factor (GM-CSF) are co-loaded into a macroporous hydrogel for long-term immune response. Rg3-LNPs could accumulate into both tumors and LNs. Rg3-LNPs targeted tumor cells with high glucose transporter-1 expression via the targeting ligand Rg3, and anchored antigens on the tumor cell surface, thus promoting the recognition of CTL to tumor cells; Rg3-LNPs can accumulate into the LNs to promote DC activation and antigen presentation, thus stimulating CTL activation. Besides, Rg3, as an adjuvant, cooperated with GM-CSF to remodel the tumor microenvironment, thus promoting the killing of CTL to tumor cells. Collectively, this work highlights the importance of tagging antigens to tumor cells in tumor vaccine and has great clinical value for immune-escaping tumors.

Inhibiting fibronectin assembly in the breast tumor microenvironment increases cell death and improves response to doxorubicin

Purpose

Effective therapies for solid tumors, including breast cancers, are hindered by several roadblocks that can be largely attributed to the fibrotic extracellular matrix (ECM). Fibronectin (FN) is a highly upregulated ECM component in the fibrotic tumor stroma and is associated with poor patient prognosis. This study aimed to investigate the therapeutic potential of an anti-fibrotic peptide that specifically targets FN and blocks the fibrillar assembly of FN.

Methods

To target FN, we used PEGylated Functional Upstream Domain (PEG-FUD), which binds to the 70 kDa N-terminal region of FN with high affinity, localizes to mammary tumors, and potently inhibits FN assembly in vitro and in vivo. Here, we used the 4T1 tumor model to investigate the efficacy and mechanisms of PEG-FUD to inhibit tumor growth.

Results

Our data demonstrates that PEG-FUD monotherapy reduces tumor growth without systemic toxicity. Analysis of the tumor microenvironment revealed that PEG-FUD effectively inhibited FN matrix assembly within tumors and reduced adhesion-mediated signaling through α5 integrin and FAK leading to enhanced tumor cell death. Notably, signaling through FAK has been associated with resistance mechanisms to doxorubicin (DOX). Therefore, we tested the combination of PEG-FUD and Dox, which significantly reduced tumor growth by 60% compared to vehicle control and 30% compared to Dox monotherapy.

Conclusions

Our findings demonstrate that PEG-FUD significantly modifies the peritumoral ECM of breast cancer, leading to increased tumor cell death, and potentiates the efficacy of conventional breast cancer therapy.

Currents status of radiotracers for breast cancer imaging in PET

Radiolabeled molecules have become valuable tools in the diagnosis, monitoring, and treatment of cancer, particularly breast cancer. Through the use of radiotracers, clinicians can target specific tumor cells, assess microenvironments, and identify metastases. These radiopharmaceuticals, based on radionuclides, enable both imaging and therapeutic applications, leading to personalized cancer treatment. Techniques such as PET, SPECT, and the use of nanoparticles for theranostics are at the forefront of innovation, offering improved precision in both diagnosis and therapy. This review explores the various ways in which radiotracers are leveraged in modern oncology, with a focus on breast cancer, and highlights recent advancements in targeted radionuclide therapy and nanoparticle-based applications.

The fibronectin-targeting PEG-FUD imaging probe shows enhanced uptake during fibrogenesis in experimental lung fibrosis

Progressive forms of interstitial lung diseases, including idiopathic pulmonary fibrosis (IPF), are deadly disorders lacking non-invasive biomarkers for assessment of early disease activity, which presents a major obstacle in disease management. Excessive extracellular matrix (ECM) deposition is a hallmark of these disorders, with fibronectin being an abundant ECM glycoprotein that is highly upregulated in early fibrosis and serves as a scaffold for the deposition of other matrix proteins. Due to its role in active fibrosis, we are targeting fibronectin as a biomarker of early lung fibrosis disease activity via the PEGylated fibronectin-binding polypeptide (PEG-FUD). In this work, we demonstrate the binding of PEG-FUD to the fibrotic lung throughout the course of bleomycin-induced murine model of pulmonary fibrosis. We first analyzed the binding of radiolabeled PEG-FUD following direct incubation to precision cut lung slices from mice at different stages of experimental lung fibrosis. Then, we administered fluorescently labeled PEG-FUD subcutaneously to mice over the course of bleomycin-induced pulmonary fibrosis and assessed peptide uptake 24 h later through ex vivo tissue imaging. Using both methods, we found that peptide targeting to the fibrotic lung is increased during the fibrogenic phase of the single dose bleomycin lung fibrosis model (days 7 and 14 post-bleomycin). At these timepoints we found a correlative relationship between peptide uptake and fibrotic burden. These data suggest that PEG-FUD targets fibronectin associated with active fibrogenesis in this model, making it a promising candidate for a clinically translatable molecular imaging probe to non-invasively determine pulmonary fibrosis disease activity, enabling accelerated therapeutic decision-making.

Rationally modified SNX-class Hsp90 inhibitors disrupt extracellular fibronectin assembly without intracellular Hsp90 activity

Despite Hsp90's well documented promise as a target for developing cancer chemotherapeutics, its inhibitors have struggled to progress through clinical trials. This is, in part, attributed to the cytoprotective compensatory heat shock response (HSR) stimulated through intracellular Hsp90 inhibition. Beyond its intracellular role, secreted extracellular Hsp90 (eHsp90) interacts with numerous pro-oncogenic extracellular clients. This includes fibronectin, which in the tumour microenvironment enhances cell invasiveness and metastasis. Through the rational modification of known Hsp90 inhibitors (SNX2112 and SNX25a) we developed four Hsp90 inhibitory compounds, whose alterations restricted their interaction with intracellular Hsp90 and did not stimulate the HSR. Two of the modified cohort (compounds 10 and 11) were able to disrupt the assembly of the extracellular fibronectin network at non-cytotoxic concentrations, and thus represent promising new tool compounds for studying the druggability of eHsp90 as a target for inhibition of tumour invasiveness and metastasis.

[64Cu]Cu-PEG-FUD peptide for noninvasive and sensitive detection of murine pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease resulting in irreversible scarring within the lungs. However, the lack of biomarkers that enable real-time assessment of disease activity remains a challenge in providing efficient clinical decision-making and optimal patient care in IPF. Fibronectin (FN) is highly expressed in fibroblastic foci of the IPF lung where active extracellular matrix (ECM) deposition occurs. Functional upstream domain (FUD) tightly binds the N-terminal 70-kilodalton domain of FN that is crucial for FN assembly. In this study, we first demonstrate the capacity of PEGylated FUD (PEG-FUD) to target FN deposition in human IPF tissue ex vivo. We subsequently radiolabeled PEG-FUD with 64Cu and monitored its spatiotemporal biodistribution via μPET/CT imaging in mice using the bleomycin-induced model of pulmonary injury and fibrosis. We demonstrated [64Cu]Cu-PEG-FUD uptake 3 and 11 days following bleomycin treatment, suggesting that radiolabeled PEG-FUD holds promise as an imaging probe in aiding the assessment of fibrotic lung disease activity.

Fibronectin-targeted FUD and PEGylated FUD peptides for fibrotic diseases

Tissue fibrosis is characterized by excessive deposition of extracellular matrix (ECM) molecules. Fibronectin (FN) is a glycoprotein found in the blood and tissues, a key player in the assembly of ECM through interaction with cellular and extracellular components. Functional Upstream Domain (FUD), a peptide derived from an adhesin protein of bacteria, has a high binding affinity for the N-terminal 70-kDa domain of FN that plays a crucial role in FN polymerization. In this regard, FUD peptide has been characterized as a potent inhibitor of FN matrix assembly, reducing excessive ECM accumulation. Furthermore, PEGylated FUD was developed to prevent rapid elimination of FUD and enhance its systemic exposure in vivo. Herein, we summarize the development of FUD peptide as a potential anti-fibrotic agent and its application in experimental fibrotic diseases. In addition, we discuss how modification of the FUD peptide via PEGylation impacts pharmacokinetic profiles of the FUD peptide and can potentially contribute to anti-fibrosis therapy.