Prodrug micelle-based nanomedicine for cancer treatment

Prodrug-based nanomedicines for rheumatoid arthritis

Most antirheumatic drugs with high toxicity exhibit a narrow therapeutic window due to their nonspecific distribution in the body, leading to undesirable side effects and reduced patient compliance. To in response to these challenges, prodrug-based nanoparticulate drug delivery systems (PNDDS), which combines prodrug strategy and nanotechnology into a single system, resulting their many advantages, including stability for prodrug structure, the higher drug loading capacity of the system, improving the target activity and bioavailability, and reducing their untoward effects. PNDDS have gained attention as a method for relieving arthralgia syndrome of rheumatoid arthritis in recent years. This article systematically reviews prodrug-based nanocarriers for rheumatism treatment, including Nano systems based on prodrug-encapsulated nanomedicines and conjugate-based nanomedicines. It provides a new direction for the clinical treatment of rheumatoid arthritis.

pH/redox dual-sensitive platinum (IV)-based micelles with greatly enhanced antitumor effect for combination chemotherapy

To achieve precise control of nano-carrier structure and drug release behavior, we designed a pH/redox dual-responsive polymeric prodrug by condensation polymerization using octahedrally coordinated cisplatin (Pt IV) and ortho ester monomer. The prodrug was then self-assembled with doxorubicin (DOX) in aqueous solution to give a synergetic drug delivery system. The polymer backbone can completely degrade and release cisplatin (Pt II) and DOX under the acidic and reductive environment of tumor cells, owing to the breakage of ortho ester bonds and the reduction of Pt (IV). The size and micromorphology of micelles were observed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). In vitro study of drug release, cellular uptake and cytotoxicity revealed that the micelles could be triggered intracellularly to release two drugs. In vivo drug distribution and antitumor activity also provide the evidence for the excellent antitumor effect of micelles.

pH- and GSH-Sensitive Hyaluronic Acid-MP Conjugate Micelles for Intracellular Delivery of Doxorubicin to Colon Cancer Cells and Cancer Stem Cells

A dual-sensitive polymeric drug conjugate (HA-SS-MP) was synthesized by conjugating hydrophobic 6-mercaptopurine (MP) to thiolated hyaluronic acid (HA) as the carrier and ligand to deliver doxorubicin (Dox) to parental colon cancer and colon cancer stem cells. Because of the amphiphilic nature of HA-SS-MP, it was self-assembled in the aqueous media, and Dox was physically encapsulated in the core of the micelles. The particle size and the zeta potential of the micelle were analyzed by dynamic light scattering (DLS), and the morphology of the micelle was investigated using transmission electron microscopy (TEM). Drug release study results revealed more drug release at pH 5.0 in the presence of GSH than that at the physiological pH value. The cytotoxicity of free Dox was slightly greater than that of Dox-loaded HA-SS-MP micelles. In vitro cytotoxicity of HA-SS-MP and Dox-loaded HA-SS-MP micelles was greater for cancer stem cells (HCT116-CSCs) than for parental HCT116 colon cancer cells and L929 normal fibroblast cells. The MTT and flow cytometry results confirmed that free HA competitively inhibited Dox-loaded HA-SS-MP uptake. Similarly, flow cytometry results revealed anti-CD44 antibody competitively inhibited cellular uptake of Rhodamine B isothiocyanate conjugated micelles, which confirms that the synthesized micelle is uptaken via CD44 receptor. Cell cycle analysis revealed that free drugs and Dox-loaded HA-SS-MP arrested parental HCT116 colon cancer cells at the S phase, while cell arrest was observed at the G0G1 phase in HCT116-CSCs. In addition, ex vivo biodistribution study showed that Dox-loaded HA-SS-MP micelles were accumulated more in the tumor region than in any other organ. Furthermore, the in vivo results revealed that Dox-loaded HA-SS-MP micelles exhibited more therapeutic efficacy than the free drugs in inhibiting tumor growth in BALB/C nude mice. Overall, the results suggested that the synthesized micelles could be promising as a stimuli carrier and ligand for delivering Dox to colon cancer cells and also to eradicate colon cancer stem cells.

Polyamino acid-based gemcitabine nanocarriers for targeted intracellular drug delivery

In the present study, we have successfully fabricated a biocompatible polyamino acid-based nanocarrier with reduction-sensitivity and targeting ability for gemcitabine (GEM) delivery.

A unique highly hydrophobic anticancer prodrug self-assembled nanomedicine for cancer therapy

In contrast with common thought, we generated highly hydrophobic anticancer prodrug self-assembled nanoparticles without the aid of surface active substances, based on the conjugation of docetaxel to d-α-tocopherol succinate. The reduction-sensitive prodrug was synthesized with a disulfide bond inserted into the linker and was compared with a control reduction-insensitive prodrug. The morphology and stability of self-assembled nanoparticles were investigated. Cytotoxicity and apoptosis assays showed that the reduction-sensitive nanoparticles had higher anticancer activity than the reduction-insensitive nanoparticles. The reduction-sensitive nanoparticles exhibited favorable in vivo antitumor activity and tolerance compared with docetaxel Tween80-containing formulation and the reduction-insensitive nanoparticles. Taken together, the unique nanomedicine demonstrated a number of advantages: (i) ease and reproducibility of preparation, (ii) high drug payload, (iii) superior stability, (iv) prolonged circulation, and (v) improved therapeutic effect. This highly reproducible molecular assembly strategy should motivate the development of new nanomedicines.

Tunable self-assembly of Irinotecan-fatty acid prodrugs with increased cytotoxicity to cancer cells

The development of a clinical chemotherapeutic is not an easy task. One challenge is how to deliver the agent to cancer cells. Nano-formulation of prodrugs, which combines the strengths of nanotechnology and prodrugs, possesses many advantages for chemotherapeutic drug delivery, including high drug loading efficiency, improved drug availability and enhanced accumulation in cancer cells. Here, we have constructed a small library of Irinotecan-derived prodrugs, in which the 20-hydroxyl group was derived with fatty-acid moieties through esterification. This conjugation fine-tuned the polarity of the Irinotecan molecule, thus enhancing the lipophilicity of the prodrugs and inducing their self-assembly into nanoparticles with different morphologies. These nano-formulated prodrugs accumulated at higher levels in cancer cells and were much more cytotoxic than free drugs. The rational design of prodrug-based nano-formulations opens a new avenue for the engineering of more efficient drug-delivery systems.

Combination delivery of Adjudin and Doxorubicin via integrating drug conjugation and nanocarrier approaches for the treatment of drug-resistant cancer cells

Combination therapy has been regarded as a potent strategy to overcome multidrug resistance (MDR). In this study, we adopt Adjudin (ADD), a mitochondria inhibitor, and Doxorubicin (DOX), a common chemo-drug, to treat drug-resistant cancer cells (MCF-7/ADR) in combination. Given the different physico-chemical properties of ADD and DOX, we develop a novel drug formulation (ADD-DOX (M)) by integrating drug conjugation and nanocarrier approaches to realize the co-delivery of the two drugs. We demonstrate the conjugation of ADD and DOX via formation of an acid-sensitive hydrazone bond, and then the encapsulation of ADD-DOX conjugates by DSPE-PEG₂₀₀₀ micelles with high drug encapsulation efficiency and well-controllable drug loading efficiency. The obtained ADD-DOX (M) micelles are found to be stable under physiological conditions, but can rapidly release drugs within acidic environments. Following cellular experiments confirm that ADD-DOX (M) vehicles can be internalized by MCF-7/ADR cancer cells through an endocytic pathway and exist within the moderate acidic endolysosomes, thus accelerating the hydrolysis of ADD-DOX and the release of free ADD and DOX. As a result, the ADD-DOX (M) formulation exhibits an excellent anti-MDR effect. In summary, we for the first time report the combinational use of ADD and DOX with an effective co-delivery strategy for the treatment of MDR cancer cells.

Prodrug-based nanoparticulate drug delivery strategies for cancer therapy

Despite the rapid developments in nanotechnology and biomaterials, the efficient delivery of chemotherapeutic agents is still challenging. Prodrug-based nanoassemblies have many advantages as a potent platform for anticancer drug delivery, such as improved drug availability, high drug loading efficiency, resistance to recrystallization upon encapsulation, and spatially and temporally controllable drug release. In this review, we discuss prodrug-based nanocarriers for cancer therapy, including nanosystems based on polymer-drug conjugates, self-assembling small molecular weight prodrugs and prodrug-encapsulated nanoparticles (NPs). In addition, we discuss new trends in the field of prodrug-based nanoassemblies that enhance the delivery efficiency of anticancer drugs, with special emphasis on smart stimuli-triggered drug release, hybrid nanoassemblies, and combination drug therapy.