Stromal Barrier-Dismantled Nanodrill-Like and Cancer Cell-Targeted pH-Responsive Polymeric Micelles for Further Enhancing the Anticancer Efficacy of Doxorubicin

Bioorthogonal Chemistry-Guided Inhalable Nanoprodrug to Circumvent Cisplatin Resistance in Orthotopic Nonsmall Cell Lung Cancer

Pulmonary delivery of anticancer therapeutics has shown encouraging performance in treating nonsmall cell lung cancer (NSCLC), which is characterized by high aggressiveness and poor prognosis. Cisplatin, a key member of the family of DNA alkylating agents, is extensively employed during NSCLC therapy. However, the development of chemoresistance and the occurrence of side effects severely impede the long-term application of cisplatin-based chemotherapies. Herein, we propose a meaningful strategy to precisely treat cisplatin-resistant NSCLC based on the combination of bioorthogonal chemistry with an inhalation approach. Ethacraplatin (EA-Pt), a platinum prodrug (IV), was synthesized and encapsulated in nitric oxide (NO)-containing micelles to overcome cisplatin chemoresistance. By further modifying bioorthogonal molecules in this nanoplatform (EA-Pt@MDBCO), an improved targeting performance toward pulmonary cancerous regions is achieved after prelabeling with azide via inhalation. Upon entering acidic cancer cells, EA-Pt is swiftly released due to the pH sensitivity of bioorthogonal micelles, which enables its bifunctions to inhibit glutathione S-transferase activity and deplete intracellular glutathione, eventually reversing cisplatin resistance. Moreover, the released NO also improves the overall therapeutic outcome against NSCLC. Consequently, inhalable EA-Pt@MDBCO prelabeled by azide effectively inhibits the progression of cisplatin-resistant orthotopic NSCLC, offering a feasible nanostrategy to expand the treatment options for NSCLC.

The Application of Nanoparticles Targeting Cancer-Associated Fibroblasts

Cancer-associated fibroblasts (CAF) are the most abundant stromal cells in the tumor microenvironment (TME), especially in solid tumors. It has been confirmed that it can not only interact with tumor cells to promote cancer progression and metastasis, but also affect the infiltration and function of immune cells to induce chemotherapy and immunotherapy resistance. So, targeting CAF has been considered an important method in cancer treatment. The rapid development of nanotechnology provides a good perspective to improve the efficiency of targeting CAF. At present, more and more researches have focused on the application of nanoparticles (NPs) in targeting CAF. These studies explored the effects of different types of NPs on CAF and the multifunctional nanomedicines that can eliminate CAF are able to enhance the EPR effect which facilitate the anti-tumor effect of themselves. There also exist amounts of studies focusing on using NPs to inhibit the activation and function of CAF to improve the therapeutic efficacy. The application of NPs targeting CAF needs to be based on an understanding of CAF biology. Therefore, in this review, we first summarized the latest progress of CAF biology, then discussed the types of CAF-targeting NPs and the main strategies in the current. The aim is to elucidate the application of NPs in targeting CAF and provide new insights for engineering nanomedicine to enhance immune response in cancer treatment.

Esterase-Responsive Polymeric Micelles Containing Tetraphenylethene and Poly(ethylene glycol) Moieties for Efficient Doxorubicin Delivery and Tumor Therapy

Enzyme-responsive drug delivery systems have drawn much attention in the field of cancer theranostics due to their high sensitivity and substrate specificity under mild conditions. In this study, an amphiphilic polymer T1 is reported, which contains a tetraphenylethene unit and a poly(ethylene glycol) chain linked by an esterase-responsive phenolic ester bond. In aqueous solution, T1 formed stable micelles via self-assembly, which showed an aggregation-induced emission enhancement of 32-fold at 532 nm and a critical micelle concentration of 0.53 μM as well as esterase-responsive activity. The hydrophobic drug doxorubicin (DOX) was efficiently encapsulated into the micelles with a drug loading of 21%. In the presence of the esterase, the selective decomposition of drug-loaded T1 micelles was observed, and DOX was subsequently released with a half-life of 5 h. In vitro antitumor studies showed that T1@DOX micelles exhibited good therapeutic effects on HeLa cells, while normal cells remained mostly intact. In vivo anticancer experiments revealed that T1@DOX micelles indeed suppressed tumor growth and had reduced side effects compared to DOX·HCl. The present work showed the potential clinical application of esterase-responsive drug delivery in cancer therapy.