99mTc-labeled iRGD for single-positron emission computed tomography imaging of triple-negative breast cancer

Recent Progress of Multifunctional Molecular Probes for Triple-Negative Breast Cancer Theranostics

Breast cancer (BC) poses a significant threat to women's health, with triple-negative breast cancer (TNBC) representing one of the most challenging and aggressive subtypes due to the lack of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression. Traditional TNBC treatments often encounter issues such as low drug efficiency, limited tumor enrichment, and substantial side effects. Therefore, it is crucial to explore novel diagnostic and treatment systems for TNBC. Multifunctional molecular probes (MMPs), which integrate target recognition as well as diagnostic and therapeutic functions, introduce advanced molecular tools for TNBC theranostics. Using an MMP system, molecular drugs can be precisely delivered to the tumor site through a targeted ligand. Real-time dynamic monitoring of drug release achieved using imaging technology allows for the evaluation of drug enrichment at the tumor site. This approach enables accurate drug release, thereby improving the therapeutic effect. Therefore, this review summarizes the recent advancements in MMPs for TNBC theranostics, encompassing the design and synthesis of MMPs as well as their applications in the field of TNBC theranostics.

Ultrasound image-guided cancer gene therapy using iRGD dual-targeted magnetic cationic microbubbles

The gene therapy attracted more and more attention for the tumor therapy. To obtain a safe gene therapy system, the new gene vectors beyond the virus were developed for a high gene therapy efficiency. The ultrasound mediated gene therapy was safer and the plasmid DNA could be delivered by the microbubbles and combined with the ultrasound to increase the gene transfection efficiency. In this work, the cationic microbubbles decorated with Cyclo(Cys-Arg-Gly-Asp-Lys-Gly-Pro-AspCys) (iRGD peptides) and magnetic Fe3O4 nanoparticles (MBiM) was designed for targeted ultrasound contrast imaging guided gene therapy of tumors. The ultrasound image intensity was dramatically enhanced at the tumor site that received MBiM with the magnet applied, compared to those administrated the non-targeted microbubbles (MBb) or the microbubbles with only one target material on the surface (MBM and MBbi). The pGPU6/GFP/Neo-shAKT2 was used as a sample gene, which down regulate the AKT2 protein expression for the cancer therapy. It illustrated that MBiM/AKT2 had the highest gene transfection efficiency in the studied microbubbles mediated by the ultrasound, leading to the AKT2 protein expression downregulation and the strongest tumor killing effect in vitro and in vivo. In summary, a novel and biocompatible gene delivery platform via MBiM with both the endogenous and external targeting effects for breast cancer theranostics was developed.

Cancer therapy with iRGD as a tumor-penetrating peptide

One of the primary threats in tumor treatment revolves around the limited ability to penetrate tumor sites, leading to reduced therapeutic effectiveness, which remains a critical concern. Recently gaining importance are novel peptides, namely CRGDK/RGPD/EC (iRGD), that possess enhanced tumor-penetrating and inhibitory properties. These peptides specifically target and penetrate tumors by binding to αvβ integrins, namely αvβ3 and αvβ5, as well as NRP-1 receptors. Remarkably abundant on both the vasculature and tumor cell surfaces, these peptides show promising potential for improving tumor treatment outcomes. As a result, iRGD penetrated deep into the tumor tissues with biological products, contrast agents (imaging agents), antitumor drugs, and immune modulators after co-injecting them with peptides or chemically linked to peptides. The synthesis of iRGD peptides is a relatively straightforward process compared to the synthesis of other traditional peptides, and they significantly improved tumor tissue penetration inhibiting tumor metastasis effectively. Recent studies demonstrate the effectiveness of iRGD-driven dual-targeting chemotherapeutics on cancer cells, and the nanocarriers were modified with iRGD, serving as a favorable delivery strategy of payloads for deeper tumor regions. This review aims to provide an overview to emphasize the recent advancements and advantages of iRGD in treating and imaging various cancers.

Neuropilin 1-targeted near-infrared fluorescence probes for tumor diagnosis

Two neuropilin 1 (NRP1)-targeted near-infrared fluorescence probes for tumor imaging were synthesized via click reaction. These two probes achieve excellent solubility and less aggregation. Importantly, they were able to rapidly target NRP1-overexpressing tumors and had long retention within tumors. Additionally, QS-1 with appropriate hydrophilicity displays higher tumor to muscle (T/M) ratio. And QS-1 can be easily modified with other functional group, and serve as a platform for constructing dual-modal or dual-targeting probes.

FD-1050@NPs-cRGD: A novel NIR-II fluorophore for triple-negative breast cancer imaging

Triple-negative breast cancer (TNBC) is a highly heterogeneous and aggressive disease that is prone to metastasis and recurrence. It accounts for 15-20% of all breast cancer cases. Surgical resection is effective in removing most of the malignant tissues for non-metastasized tumors; however, some residual tumor tissues would be left, leading to a poor prognosis. Thus, real-time monitoring of surgical resection would be beneficial for the surgical resection of tumors. Although NIR-II fluorescent probe-guided surgical resection has been widely used for other types of diseases, it is not currently used for TNBC in clinical practice. Here, we describe the design and synthesis of a novel NIR-II fluorescent probe, FD-1050@NPs-cRGD, that targets TNBC. We found that it has a high fluorescence quantum efficiency, good stability, and low cytotoxicity. In vivo imaging in mice demonstrated a high tumor signal/normal tissue signal ratio, indicating that FD-1050@NPs-cRGD has great potential to be applied in tumor imaging of TNBC.