Cancer drug delivery in the nano era: An overview and perspectives (Review)

Abstract

Nanomaterials are increasingly used as drug carriers for cancer therapy. Nanomaterials also appeal to researchers in the areas of cancer diagnosis and biomarker discovery. Several antitumor nanodrugs are currently being tested in preclinical and clinical trials and show promise in therapeutic and other settings. We review the development of nanomaterial drug carriers, including liposomes, polymer nanoparticles, dendritic polymers, and nanomicelles, for the diagnosis and treatment of various cancers. The prospects of nanomaterials as drug carriers for future clinical applications are also discussed.

Figure 1.

Timeline of the development of nanomedicines. Liposomes (5), polymeric systems (151), dendrimers (152), and PEGylated liposomes (153) were developed as nanodrug carriers in the early phase of discovery (before 1995). Doxil (doxorubicin) was the first FDA-approved liposome for use in cancer (154). As nanomedicine developed, the non-PEGylated liposome Myocet (doxorubicin) (155), the albumin-based nanoparticle (NP) Abraxane (doxorubicin) (63), the PEG-PLA polymeric micelle Genexol-PM (paclitaxel) (98), the vincristine sulfate liposome Marqibo (156), the iron oxide NP NanoTherm (157), and the targeted ado-trastuzumab emtansine (DM1) liposome Kadcyla (158) have been approved for clinical use. PEG-PLGA polymeric NPs (BIND-014) completed phase II clinical trials in advanced cancers (68) and anti-epidermal growth factor receptor (EGFR) immunoliposomes is in phase II clinical trials recruiting of breast cancer (159,160). The physical properties of upconversion nanoparticles (UCNPs) used in photodynamic therapy (PDT) also represent a promising direction in future research (115).

Figure 2.

Nanomaterials used as drug carriers for cancer therapy. With their distinct biological characteristics, nanomaterials can improve the enhanced permeability and retention effect, increase bioavailability, reduce the toxicity of chemotherapy drugs, release hydrophobic or hydrophilic chemotherapy drugs into the bloodstream, and achieve cytotoxic effects against cancer cells. CNTs, carbon nanotubes; QDs, quantum dots; MSNs, metal nanoparticles.

Figure 3.

Lipid bilayer-wrapped nanoporous drug delivery system in protocells. It can be decorated with multi-types chemotherapy agents and surface-targeting molecules.

Figure 4.

Structure of a dendrimer with four generations of side branches. Each generation is represented with a different color.