Extracellular Matrix Degrading Enzymes for Nanocarrier-Based Anticancer Therapy

Theranostic nanoparticles for detection and treatment of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most recalcitrant cancers due to its late diagnosis, poor therapeutic response, and highly heterogeneous microenvironment. Nanotechnology has the potential to overcome some of the challenges to improve diagnostics and tumor-specific drug delivery but they have not been plausibly viable in clinical settings. The review focuses on active targeting strategies to enhance pancreatic tumor-specific uptake for nanoparticles. Additionally, this review highlights using actively targeted liposomes, micelles, gold nanoparticles, silica nanoparticles, and iron oxide nanoparticles to improve pancreatic tumor targeting. Active targeting of nanoparticles toward either differentially expressed receptors or PDAC tumor microenvironment (TME) using peptides, antibodies, small molecules, polysaccharides, and hormones has been presented. We focus on microenvironment-based hallmarks of PDAC and the potential for actively targeted nanoparticles to overcome the challenges presented in PDAC. It describes the use of nanoparticles as contrast agents for improved diagnosis and the delivery of chemotherapeutic agents that target various aspects within the TME of PDAC. Additionally, we review emerging nano-contrast agents detected using imaging-based technologies and the role of nanoparticles in energy-based treatments of PDAC. This article is categorized under: Implantable Materials and Surgical Technologies > Nanoscale Tools and Techniques in Surgery Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

Targeting Tumors Using Peptides

To penetrate solid tumors, low molecular weight (Mw < 10 KDa) compounds have an edge over antibodies: their higher penetration because of their small size. Because of the dense stroma and high interstitial fluid pressure of solid tumors, the penetration of higher Mw compounds is unfavored and being small thus becomes an advantage. This review covers a wide range of peptidic ligands—linear, cyclic, macrocyclic and cyclotidic peptides—to target tumors: We describe the main tools to identify peptides experimentally, such as phage display, and the possible chemical modifications to enhance the properties of the identified peptides. We also review in silico identification of peptides and the most salient non-peptidic ligands in clinical stages. We later focus the attention on the current validated ligands available to target different tumor compartments: blood vessels, extracelullar matrix, and tumor associated macrophages. The clinical advances and failures of these ligands and their therapeutic conjugates will be discussed. We aim to present the reader with the state-of-the-art in targeting tumors, by using low Mw molecules, and the tools to identify new ligands.

Reducing Interstitial Fluid Pressure and Inhibiting Pulmonary Metastasis of Breast Cancer by Gelatin Modified Cationic Lipid Nanoparticles

Interstitial fluid pressure (IFP) in tumor is much higher than that in normal tissue, and it constitutes a great obstacle for the delivery of antitumor drugs, thus becoming a potential target for cancer therapy. In this study, cationic nanostructured lipid carriers (NLCs) were modified by low molecular weight gelatin to achieve the desirable reduction of tumor IFP and improve the drug delivery. In this way, the chemotherapy of formulations on tumor proliferation and pulmonary metastasis was further improved. The nanoparticles were used to load three drugs, docetaxel (DTX), quercetin (Qu), and imatinib (IMA), with high encapsulation efficiency of 89.54%, 96.45%, and 60.13%, respectively. GNP-DTX/Qu/IMA nanoparticles exhibited an enzyme-sensitive drug release behavior, and the release rate could be mediated by matrix metalloproteinases (MMP-9). Cellular uptake and MTT assays showed that the obtained GNP-DTX/Qu/IMA could be internalized into human breast 4T1 cells effectively and exhibited the strongest cytotoxicity. Moreover, GNP-DTX/Qu/IMA demonstrated obvious advantages in inducing apoptosis and mediating the expression of apoptosis-related proteins (Caspase 3, Caspase 9, and bcl-2). In the wound-healing assay, GNP-DTX/Qu/IMA exhibited evidently inhibition of cell migration. The benefits of tumor IFP reduction induced by GNP-DTX/Qu/IMA were further proved after a continuous administration to 4T1 tumor-bearing mice. Finally, in the in vivo antitumor assays, GNP-DTX/Qu/IMA displayed stronger antitumor efficiency as well as suppression on pulmonary metastasis. In conclusion, the GNP-DTX/Qu/IMA system might be a promising strategy for metastatic breast cancer treatment.