Extracellularly Activated Nanocarriers: A New Paradigm of Tumor Targeted Drug Delivery

Abstract

One of the main goals of nanomedicine is to develop a nanocarrier that can selectively deliver anticancer drugs to the targeted tumors. Extensive efforts have resulted in several tumor-targeted nanocarriers, some of which are approved for clinical use. Most nanocarriers achieve tumor-selective accumulation through the enhanced permeability and retention effect. Targeting molecules such as antibodies, peptides, ligands, or nucleic acids attached to the nanocarriers further enhance their recognition and internalization by the target tissues. While both the stealth and targeting features are important for effective and selective drug delivery to the tumors, achieving both features simultaneously is often found to be difficult. Some of the recent targeting strategies have the potential to overcome this challenge. These strategies utilize the unique extracellular environment of tumors to change the long-circulating nanocarriers to release the drug or interact with cells in a tumor-specific manner. This review discusses the new targeting strategies with recent examples, which utilize the environmental stimuli to activate the nanocarriers. Traditional strategies for tumor-targeted nanocarriers are briefly discussed with an emphasis on their achievements and challenges.

Maghemite Functionalization for Antitumor Drug Vehiculization

“…This product exhibits good doxorubicin retention with increased time within circulatory system, and moreover it shows that its efficacy is six times higher than that of free therapeutic drug. It has been authorized for the therapy of ovarian cancer, metastatic breast cancer and Kaposi s sarcoma (Gullotti & Yeo, 2009). The tumor-targeting capability of chitosan nanocompounds with glycol coating and cisplatin loading has been as well demonstrated in in vivo studies.…”

In vitro study of novel gadolinium-loaded liposomes guided by GBI-10 aptamer for promising tumor targeting and tumor diagnosis by magnetic resonance imaging

“…Both NTLs and GTLs had average diameters at ~120 nm with a narrow particle size distribution index (,0.30), implying their good dispersion stability, which may be an optimal size for tumor targeting by the EPR effect. 44 GTLs showed a larger size than NTLs (P,0.05) owing to loading NH 2 -GBI-10 aptamers onto the surface of PTLs. Furthermore, NTLs exhibited a nearly neutral potential, whereas GTLs had a more negative charge (P,0.05).…”

Nanotechnology-based approaches in anticancer research

“…33,34 Internalization in cancer cells is an important step, because it reduces the dispersal of the drug outside the cancerous cell and can enhance the therapeutic potential of the said drug. [35][36][37] Passive targeting approaches have also been reported for the delivery of NPs in angiogenesis as a compensatory mechanism of diffusion. It depends upon the properties of NPs, such as, size, surface nature, and circulation half-life.…”