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Advanced strategies have been developed to overcome limitations of traditional pharmacological treatments like low specificity and severe side effects. Remarkably, the application of nano drug delivery systems (NDDS) to improve intracellular uptake has promising prospects. Among other proposed materials, metal-organic frameworks (MOFs) formed by the assembly of metal ions and organic ligands exhibit excellent advantages as a nanocarrier, such as high drug loading, excellent biocompatibility and biodegradability, controllable drug release as well as easy modification. Thus, MOFs are widely used in NDDS. Based on this, scientists devoted much effort to designing multi-functional and versatile MOFs to achieve desirable therapeutic effects. This review introduced the latest MOFs for tumor treatment. Here, the classification of MOFs was introduced and, some responsive MOFs to control the release behavior of drugs were reviewed. Besides, some advanced active targeting MOFs to improve drug accumulation in tumor were summarized. Finally, the remaining challenges encountered by MOFs were discussed and proposed, which could provide guidance for developing more intelligent NDDS based on the promising materials of MOFs.

The therapeutic efficacy of most chemotherapeutic drugs is hampered by low water solubility, poor stability, serious side effects, and lack of tumor selectivity. To solve these issues, chondroitin sulfate (CS)-based redox-responsive nanoparticles were developed. The amphiphilic polymer, CS-alpha-tocopherol succinate (TOS) (CS-CYS-TOS), was constructed by conjugating TOS on the CS backbone via cystamine (CYS) as a redox-sensitive linker, which could self-assemble to form polymeric nanoparticles in phosphate buffer saline (PBS). The resulting nanoparticles had low critical aggregation concentration (CAC) of 0.027–0.040 mg/mL, small size, and narrow size distribution. The docetaxel (DTX)-loaded nanoparticles were fabricated by the sonication method with high drug loading (DL) of 17.06% ± 0.97. The dynamic light scattering (DLS) and transmission electron microscope (TEM) had shown spherical nanoparticles with a size of 170.7 nm ± 2.8 and ~160 nm, respectively, and zeta potential of −26.5 mV ± 1.5. The results of the reduction-triggered disassembly behavior study and in vitro release study revealed the redox-sensitive potential of CS-CYS-TOS nanoparticles. The nanoparticles exhibited time-dependent qualitative and quantitative uptake by melanoma cells. The Sulforhodamine B (SRB) assay indicated the safety of carrier material and enhanced anti-tumor activity of DTX-loaded nanoparticles. The in vivo biological performance of nanoparticles in tumor-bearing mice was evaluated and DTX/CS-CYS-TOS nanoparticles were superior in terms of tumor volume inhibition than other formulations. This nanoparticulate system responded to the reducing conditions in tumor cells, released drugs quickly and thoroughly, thereby improved the efficacy of chemotherapy.

Paclitaxel is an anti-tumor drug that is effective in the treatment of various tumors, but its applications are limited due to its poor water solubility, short biological half-life and severe side effects. A tumor has many features that are different from normal tissues, such as mild acidity, strong reducing environment and over-expressed certain enzymes. Many smart micelles sensitive to internal or external stimuli have been developed that could realize the release of drug at tumor site. In addition, micelles could improve the aqueous solubility, potentiate therapeutic efficacy and, reduce the side effects of drugs to the normal tissues. This review summarizes recent studies on stimuli-responsive micelles for the delivery of paclitaxel and their potential applications in cancer therapy.

Paclitaxel (PTX) is one of the natural products used as first- or second-line treatment of cancer. It has a wide spectrum of activity against various cancer types, but low solubility in water, and toxicity to normal tissues such as hypersensitivity reaction and neuropathy limited its applications. The serious endeavors have been made to design and fabricate a more favorable nanoformulation lowering the inherent toxicity and side effects of PTX. The polymer-drug conjugates as a class of polymer-based nanomedicines have been reported to reduce adverse effects, enhance uptake and accumulation in tumor cells, potentiate therapeutic efficacy and improve patient compliance compared to polymer-encapsulated drugs. Collectively, very “old” PTX as cytotoxic drug bound to polymer has enormous potential and broad prospects. In this review, we mainly pay attention to summarize progress in the polymer-PTX conjugates designed and evaluated in recent decades to potentiate the therapeutic efficacy and tackle adverse effects of PTX.