Octreotide Functionalized Nano-Contrast Agent for Targeted Magnetic Resonance Imaging

Review of the Role of Nanotechnology in Overcoming the Challenges Faced in Oral Cancer Diagnosis and Treatment

Throughout the world, oral cancer is a common and aggressive malignancy with a high risk of morbidity, mortality, and recurrence. The importance of early detection in cancer prevention and disease treatment cannot be overstated. Conventional therapeutic strategies have minor difficulties but considerable side effects and unfavourable consequences in clinical applications. Hence, there is a requirement for effective ways for early detection and treatment of oral cancer. At present, numerous forms of nanoparticles have piqued researchers' interest as a potentially useful tool for diagnostic probes and medicinal devices. Because of their inherent physicochemical properties and customizable surface modification, they are able to circumvent some of restrictions and accomplish the intended diagnostic and therapeutic impact. Nanotechnology is a unique field that has revolutionised the industry and is paving the way for new treatments for oral cancer. It can help with a better diagnosis with less harmful substances and is setting current guidelines for treatment. The use of nanotechnology in cancer diagnosis, therapy, and care improves clinical practise dramatically. The different types of nanoparticles that have been developed for the diagnosis and therapy of oral cancers will be covered in this study. The difficulties and potential uses of nanoparticles in the treatment and diagnosis of oral cancer are then highlighted. In order to emphasise existing difficulties and potential remedies for oral cancer, a prospective view of the future is also provided.

Octreotide and Octreotide-derived delivery systems

Pharmaceutical peptide Octreotide is a somatostatin analog with targeting and therapeutic abilities. Over the last decades, Octreotide has been developed and approved to treat acromegaly and neuroendocrine tumours, and Octreotide-based radioactive conjugates have been leveraged clinically to detect small neuroendocrine tumour sites. Meanwhile, variety of Octreotide-derived delivery strategies have been proposed and explored for tumour targeted therapeutics or diagnostics in preclinical or clinical settings. In this review, we especially focus on the preclinical development and applications of Octreotide-derived drug delivery systems, diagnostic nanosystems, therapeutic nanosystems and multifunctional nanosystems, we also briefly discuss challenges and prospects of these Octreotide-derived delivery systems.

Parahydrogen-induced polarization allows 2000-fold signal enhancement in biologically active derivatives of the peptide-based drug octreotide

Octreotide, a somatostatin analogue, has shown its efficacy for the diagnostics and treatment of various types of cancer, i.e., in octreotide scan, as radio-marker after labelling with a radiopharmaceutical. To avoid toxicity of radio-labeling, octreotide-based assays can be implemented into magnetic resonance techniques, such as MRI and NMR. Here we used a Parahydrogen-Induced Polarization (PHIP) approach as a cheap, fast and straightforward method. Introduction of L-propargyl tyrosine as a PHIP marker at different positions of octreotide by manual Solid-Phase Peptide Synthesis (SPPS) led to up to 2000-fold proton signal enhancement (SE). Cell binding studies confirmed that all octreotide variants retained strong binding affinity to the surface of human-derived cancer cells expressing somatostatin receptor 2. The hydrogenation reactions were successfully performed in methanol and under physiologically compatible mixtures of water with methanol or ethanol. The presented results open up new application areas of biochemical and pharmacological studies with octreotide.

Peptide-based diagnostic and therapeutic agents: Where we are and where we are heading?

Peptides are increasingly present in all branches of medicine as innovative drugs, imaging agents, theragnostic, and constituent moieties of other sophisticated drugs such as peptide-drug conjugates. Due to new developments in chemical synthesis strategies, computational biology, recombinant technology, and chemical biology, peptide drug development has made a great progress in the last decade. Numerous natural peptides and peptide mimics have been obtained and studied, covering multiple therapeutic areas. Even though peptides have been investigated across the wide therapeutic spectrum, oncology, metabolism, and endocrinology are the most frequent medical indications of them. This review summarizes the current use of and the emerging new opportunities of peptides for diagnosis and treatment of various diseases.

The Value of CTA Based on Gold Nanorod Contrast Agent in Coronary Artery Diagnosis and Plaque Property Analysis

Coronary CT angiography (CTA) with the characteristics of noninvasive and simple operation is widely used in the diagnosis of coronary artery stenosis. The choice of contrast agent exerts an important impact on the imaging quality of CTA. Conventional iodine contrast agents are easily excreted by the kidneys, from which the imaging window is short, and the imaging quality is poor. Metal nanomaterials have unique optical properties and have broad application prospects in imaging. Our aim is to explore the value of gold nanorod contrast agent in the diagnosis of coronary heart disease. A gold nanorod suspension was first prepared, and the prepared gold nanorod was uniform and had good dispersibility. It can be seen from the light absorption curve that there are two obvious peaks on the UV absorption peak of the gold nanorods. The gold nanorods were cultured in different solutions, and it was found that the particle size of the gold nanorods did not change significantly within 72 hours, indicating that the prepared gold nanorods had good stability. When observing the damage degree of mouse kidney tissue, it was shown that the damage degree of gold nanorod contrast agent to mouse kidney tissue was less than that of iodine contrast agent. The above results indicate that the gold nanorod contrast agent has good stability and safety. Therefore, our study demonstrated that the gold nanorod contrast agent has high value in the diagnosis of coronary arteries and the analysis of plaque properties.

Non-radioactive and sensitive tracking of neutrophils towards inflammation using antibody functionalized magnetic particle imaging tracers

White blood cells (WBCs) are a key component of the mammalian immune system and play an essential role in surveillance, defense, and adaptation against foreign pathogens. Apart from their roles in the active combat of infection and the development of adaptive immunity, immune cells are also involved in tumor development and metastasis. Antibody-based therapeutics have been developed to regulate (i.e. selectively activate or inhibit immune function) and harness immune cells to fight malignancy. Alternatively, non-invasive tracking of WBC distribution can diagnose inflammation, infection, fevers of unknown origin (FUOs), and cancer. Magnetic Particle Imaging (MPI) is a non-invasive, non-radioactive, and sensitive medical imaging technique that uses safe superparamagnetic iron oxide nanoparticles (SPIOs) as tracers. MPI has previously been shown to track therapeutic stem cells for over 87 days with a ~200 cell detection limit. In the current work, we utilized antibody-conjugated SPIOs specific to neutrophils for in situ labeling, and non-invasive and radiation-free tracking of these inflammatory cells to sites of infection and inflammation in an in vivo murine model of lipopolysaccharide-induced myositis. MPI showed sensitive detection of inflammation with a contrast-to-noise ratio of ~8-13.

Octreotide-Conjugated Core-Cross-Linked Micelles with pH/Redox Responsivity Loaded with Etoposide for Neuroendocrine Neoplasms Therapy and Bioimaging with Photoquenching Resistance

The study of multifunctional polymer micelles combined with chemotherapy due to reduced systemic toxicity and enhanced efficacy has attracted intensive attention. Herein, a multifunctional core-cross-linked hybrid micelle system based on mPEG- b-PGu(BA-TPE) and OCT-PEG- b-PGu(DA-TPE) with pH- and redox-triggered drug release and aggregation-induced emission (AIE) active imaging has been developed for active targeting of neuroendocrine neoplasms (NENs), especially neuroendocrine carcinomas (NECs) with poor prognosis. These micelles showed excellent biocompatibility and stability. After the formation of borate ester bonds, core-cross-linked micelles (CCLMs) showed enhanced emission properties. In addition, etoposide (ETO), one of the most important anticancer drugs of NECs, was loaded into the hydrophobic core of micelles by self-assembly with an average diameter of 274.6 nm and spherical morphology. Octreotide (OCT) conjugated onto the micelles enhanced cellular uptake by receptor-mediated endocytosis. ETO-loaded micelles demonstrated the dual-responsive triggered intracellular drug release and great tumor suppression ability in vitro. Compared with free ETO, ETO-loaded CCLMs exhibited a considerable antitumor effect and significantly reduced side effects. Considering the active tumor targeting, dual-responsive drug release and the AIE effect, the polymer micelle system will be a potential candidate for diagnosis and oncotherapy of NENs.

Targeting Somatostatin Receptors By Functionalized Mesoporous Silica Nanoparticles - Are We Striking Home?

The concept of delivering nanoformulations to desired tissues by means of targeting membrane receptors of high local abundance by ligands anchored to the nanocarrier has gained a lot of attention over the last decade. Currently, there is no unanimous opinion on whether surface functionalization of nanocarriers by targeting ligands translates into any real benefit in terms of pharmacokinetics or treatment outcomes. Having examined the published nanocarriers designed to engage with somatostatin receptors, we realized that in the majority of cases targetability claims were not supported by solid evidence of targeting ligand-targeted receptor coupling, which is the very crux of a targetability concept. Here, we present an approach to characterize targetability of mesoporous silica-based nanocarriers functionalized with ligands of somatostatin receptors. The targetability proof in our case comes from a functional assay based on a genetically-encoded cAMP probe, which allows for real-time capture of receptor activation in living cells, triggered by targeting ligands on nanoparticles. We elaborate on the development and validation of the assay, highlighting the power of proper functional tests in the characterization pipeline of targeted nanoformulations.

Nanotechnology: a promising method for oral cancer detection and diagnosis

Oral cancer is a common and aggressive cancer with high morbidity, mortality, and recurrence rate globally. Early detection is of utmost importance for cancer prevention and disease management. Currently, tissue biopsy remains the gold standard for oral cancer diagnosis, but it is invasive, which may cause patient discomfort. The application of traditional noninvasive methods-such as vital staining, exfoliative cytology, and molecular imaging-is limited by insufficient sensitivity and specificity. Thus, there is an urgent need for exploring noninvasive, highly sensitive, and specific diagnostic techniques. Nano detection systems are known as new emerging noninvasive strategies that bring the detection sensitivity of biomarkers to nano-scale. Moreover, compared to current imaging contrast agents, nanoparticles are more biocompatible, easier to synthesize, and able to target specific surface molecules. Nanoparticles generate localized surface plasmon resonances at near-infrared wavelengths, providing higher image contrast and resolution. Therefore, using nano-based techniques can help clinicians to detect and better monitor diseases during different phases of oral malignancy. Here, we review the progress of nanotechnology-based methods in oral cancer detection and diagnosis.

Tumor-penetrating Peptide Conjugated and Doxorubicin Loaded T1-T2 Dual Mode MRI Contrast Agents Nanoparticles for Tumor Theranostics

The conventional chemotherapeutics could not be traced in vivo and provide timely feedback on the clinical effectiveness of drugs.

Methods: In this study, a tumor-penetrating peptide RGERPPR (RGE) modified, Gd-DTPA conjugated, and doxorubicin (DOX) loaded Fe₃O₄@SiO₂@mSiO₂ nanoparticle drug delivery system (Fe₃O₄@SiO₂@mSiO₂/DOX-(Gd-DTPA)-PEG-RGE NPs) was prepared for tumor theranostics.

Results: The Fe₃O₄@SiO₂@mSiO₂/DOX-(Gd-DTPA)-PEG-RGE NPs showed a z-average hydrodynamic diameter of about 90 nm, and a pH-sensitive DOX release profile. The 3 T MRI results confirmed the relaxivity of the NPs (r₁ = 6.13 mM^-1S^-1, r₂ = 36.89 mM^-1S^-1). The in vitro cellular uptake and cytotoxicity assays on U87MG cells confirmed that the conjugation of RGERPPR played a significant role in increasing the cellular uptake and cytotoxicity of the NPs. The near-infrared fluorescence in vivo imaging results showed that the NPs could be significantly accumulated in the U87MG tumor tissue, which should result from the mediation of the tumor-penetrating peptide RGERPPR. The MRI results showed that the NPs offered a T₁-T₂ dual mode contrast imaging effect which would lead to a more precise diagnosis. Compared with unmodified NPs, the RGE-modified NPs showed significantly enhanced MR imaging signal in tumor tissue and antitumor effect, which should also be attributed to the tumor penetrating ability of RGERPPR peptide. Furthermore, the Hematoxylin and Eosin (H&E) staining and TUNEL assay proved that the NPs produced obvious cell apoptosis in tumor tissue.

Conclusions: These results indicated that Fe₃O₄@SiO₂@mSiO₂/DOX-(Gd-DTPA)-PEG-RGE NPs are an effective targeted delivery system for tumor theranostics, and should have a potential value in the personalized treatment of tumor.