Ultrasmall Paramagnetic Iron Oxide Nanoprobe Targeting Epidermal Growth Factor Receptor for In Vivo Magnetic Resonance Imaging of Hepatocellular Carcinoma

Exceedingly Small Magnetic Iron Oxide Nanoparticles for T1 -Weighted Magnetic Resonance Imaging and Imaging-Guided Therapy of Tumors

Magnetic iron oxide nanoparticles (MIONs) based T2 -weighted magnetic resonance imaging (MRI) contrast agents (CAs) are liver-specific with good biocompatibility, but have been withdrawn from the market and replaced with Eovist (Gd-EOB-DTPA) due to their inherent limitations (e.g., susceptibility to artifacts, high magnetic moment, dark signals, long processing time of T2 imaging, and long waiting time for patients after administration). Without the disadvantages of Gd-chelates and MIONs, the recently emerging exceedingly small MIONs (ES-MIONs) (<5 nm) are promising T1 CAs for MRI. However, there are rare review articles focusing on ES-MIONs for T1 -weighted MRI. Herein, the recent progress of ES-MIONs, including synthesis methods (the current basic synthesis methods and improved methods), surface modifications (artificial polymers, natural polymers, zwitterions, and functional protein), T1 -MRI visual strategies (structural remodeling, reversible self-assemblies, metal ions doped, T1 /T2 dual imaging modes, and PET/MRI strategy), and imaging-guided cancer therapy (chemotherapy, gene therapy, ferroptosis therapy, photothermal therapy, photodymatic therapy, radiotherapy, immuotherapy, sonodynamic therapy, and multimode therapy), is summarized. The detailed description of synthesis methods and applications of ES-MIONs in this review is anticipated to attract extensive interest from researchers in different fields and promote their participation in the establishment of ES-MIONs based nanoplatforms for tumor theranostics.

Innovative Diagnostic Peptide-Based Technologies for Cancer Diagnosis: Focus on EGFR-Targeting Peptides

Active targeting using biological ligands has emerged as a novel strategy for the targeted delivery of diagnostic agents to tumor cells. Conjugating functional targeting moieties with diagnostic probes can increase their accumulation in tumor cells and tissues, enhancing signal detection and, thus, the sensitivity of diagnosis. Due to their small size, ease of chemical synthesis and site-specific modification, high tissue penetration, low immunogenicity, rapid blood clearance, low cost, and biosafety, peptides offer several advantages over antibodies and proteins in diagnostic applications. Epidermal growth factor receptor (EGFR) is one of the most promising cancer biomarkers for actively targeting diagnostic and therapeutic agents to tumor cells due to its active involvement and overexpression in various cancers. Several peptides for EGFR-targeting have been identified in the last decades, which have been obtained by multiple means including derivation from natural proteins, phage display screening, positional scanning synthetic combinatorial library, and in silico screening. Many studies have used these peptides as a targeting moiety for diagnosing different cancers in vitro, in vivo, and in clinical trials. This review summarizes the progress of EGFR-targeting peptide-based assays in the molecular diagnosis of cancer.

Targeted Molecular Imaging Probes Based on Magnetic Resonance Imaging for Hepatocellular Carcinoma Diagnosis and Treatment

Hepatocellular carcinoma (HCC) is the sixth most commonly malignant tumor and the third leading cause of cancer-related death in the world, and the early diagnosis and treatment of patients with HCC is core in improving its prognosis. The early diagnosis of HCC depends largely on magnetic resonance imaging (MRI). MRI has good soft-tissue resolution, which is the international standard method for the diagnosis of HCC. However, MRI is still insufficient in the diagnosis of some early small HCCs and malignant nodules, resulting in false negative results. With the deepening of research on HCC, researchers have found many specific molecular biomarkers on the surface of HCC cells, which may assist in diagnosis and treatment. On the other hand, molecular imaging has progressed rapidly in recent years, especially in the field of cancer theranostics. Hence, the preparation of molecular imaging probes that can specifically target the biomarkers of HCC, combined with MRI testing in vivo, may achieve the theranostic purpose of HCC in the early stage. Therefore, in this review, taking MR imaging as the basic point, we summarized the recent progress regarding the molecular imaging targeting various types of biomarkers on the surface of HCC cells to improve the theranostic rate of HCC. Lastly, we discussed the existing obstacles and future prospects of developing molecular imaging probes as HCC theranostic nanoplatforms.

Magnetically guided theranostics: montmorillonite-based iron/platinum nanoparticles for enhancing in situ MRI contrast and hepatocellular carcinoma treatment

In Asia, including Taiwan, malignant tumors such as Hepatocellular carcinoma (HCC) one of the liver cancer is the most diagnosed subtype. Magnetic resonance imaging (MRI) has been a typical diagnostic method for accurately diagnosing HCC. When it is difficult to demonstrate non-enhanced MRI of tumors, radiologists can use contrast agents (such as Gd3+, Fe3O4, or FePt) for T1-weighted and T2-weighted imaging remain in the liver for a long time to facilitate diagnosis via MRI. However, it is sometimes difficult for T2-weighted imaging to detect small tumor lesions because the liver tissue may absorb iron ions. This makes early cancer detection a challenging goal. This challenge has prompted current research to create novel nanocomposites for enhancing the noise-to-signal ratio of MRI. To develop a method that can more efficiently diagnose and simultaneously treat HCC during MRI examination, we designed a functionalized montmorillonite (MMT) material with a porous structure to benefit related drugs, such as mitoxantrone (MIT) delivery or as a carrier for the FePt nanoparticles (FePt NPs) to introduce cancer therapy. Multifunctional FePt@MMT can simultaneously visualize HCC by enhancing MRI signals, treating various diseases, and being used as an inducer of magnetic fluid hyperthermia (MFH). After loading the drug MIT, FePt@MMT-MIT provides both MFH treatment and chemotherapy in one nanosystem. These results ultimately prove that functionalized FePt@MMT-MIT could be integrated as a versatile drugs delivery system by combining with MRI, chemotheraeutic drugs, and magnetic guide targeting.

EGFR targeting for cancer therapy: Pharmacology and immunoconjugates with drugs and nanoparticles

The epidermal growth factor receptor (EGFR) belongs to the tyrosine kinase receptors family and is present in the epithelial cell membrane. Its endogenous activation occurs through the binding of different endogenous ligands, including the epidermal growth factor (EGF), leading to signaling cascades able to maintain normal cellular functions. Although involved in the development and maintenance of tissues in normal conditions, when EGFR is overexpressed, it stimulates the growth and progression of tumors, resulting in angiogenesis, invasion and metastasis, through some main cascades such as Ras/Raf/MAPK, PIK-3/AKT, PLC-PKC and STAT. Besides, considering the limitations of conventional chemotherapy that result in high toxicity and low tumor specificity, EGFR is currently considered an important target. As a result, several monoclonal antibodies are currently approved for use in cancer treatment, such as cetuximab (CTX), panitumumab, nimotuzumab, necitumumab and others are in clinical trials. Aiming to combine the chemotherapeutic agent toxicity and specific targeting to EGFR overexpressing tumor tissues, two main strategies will be discussed in this review: antibody-drug conjugates (ADCs) and antibody-nanoparticle conjugates (ANCs). Briefly, ADCs consist of antibodies covalently linked through a spacer to the cytotoxic drug. Upon administration, binding to EGFR and endocytosis, ADCs suffer chemical and enzymatic reactions leading to the release and accumulation of the drug. Instead, ANCs consist of nanotechnology-based formulations, such as lipid, polymeric and inorganic nanoparticles able to protect the drug against inactivation, allowing controlled release and also passive accumulation in tumor tissues by the enhanced permeability and retention effect (EPR). Furthermore, ANCs undergo active targeting through EGFR receptor-mediated endocytosis, leading to the formation of lysosomes and drug release into the cytosol. Herein, we will present and discuss some important aspects regarding EGFR structure, its role on internal signaling pathways and downregulation aspects. Then, considering that EGFR is a potential therapeutic target for cancer therapy, the monoclonal antibodies able to target this receptor will be presented and discussed. Finally, ADCs and ANCs state of the art will be reviewed and recent studies and clinical progresses will be highlighted. To the best of our knowledge, this is the first review paper to address specifically the EGFR target and its application on ADCs and ANCs.

Extremely Small Iron Oxide Nanoparticle-Encapsulated Nanogels as a Glutathione-Responsive T1 Contrast Agent for Tumor-Targeted Magnetic Resonance Imaging

Activatable magnetic resonance imaging (MRI) contrast agents that can be selectively stimulated at a tumor region are urgently demanded to realize the efficient and accurate diagnosis of cancers. Here, extremely small iron oxide nanoparticles (ESIONPs) modified with citric acid (ESIONPs-CA) are encapsulated in disulfide-cross-linked poly(carboxybetaine methacrylate) (poly(CBMA)) nanogels, and a cyclo[Arg-Gly-Asp-d-Tyr-Lys] (c(RGD)) ligand is further introduced to obtain ESIONP-packaged poly(CBMA) nanogels equipped with tumor-targeted c(RGD) (ICNs-RGD). On the basis of the transformation of the clustered ESIONPs into dispersed ones induced by the reducing glutathione (GSH), ICNs-RGD can complete the conversion from a T₂ contrast agent to a T₁ one, realizing the selective activation of the T₁ contrasting effect. The GSH-dependent MRI signal conversion of ICNs-RGD is feasible in the tumor cell and tissue. Moreover, ICNs-RGD exhibits obvious targeting specificity and favorable biocompatibility. In the MRI experiments of tumor-bearing mice, benefiting from the stimuli-responsiveness toward GSH and targeting specificity, the T₁ contrasting effect of tumor tissues can be selectively enhanced after the intravenous injection of ICNs-RGD. Therefore, tumor-targeted ICNs-RGD with a switchable MRI signal derived from the activation of GSH is a potential contrast agent for the efficient and precise tumor diagnosis in the clinic.

Dual-targeting and excretable ultrasmall SPIONs for T1-weighted positive MR imaging of intracranial glioblastoma cells by targeting the lipoprotein receptor-related protein

A multifunctional targeted nanoprobe composed of ultrasmall superparamagnetic iron oxide nanoparticles with surface-conjugated Angiopep-2 was successfully constructed for targeted MR imaging of intracranial glioblastoma.