Dimeric prodrug self-assembly nanoparticles (DPS NPs) present promising avenues for chemotherapeutic delivery, yet optimizing the linker design for effective SN38 delivery remains challenging. We developed various SN38 dimeric prodrugs with differing linker lengths to explore how linker length impacts DPS NP performance. Our study reveals that linker length critically affects the nanoparticles assembly stability and activation efficiency. Specifically, too short linkers compromise assembly stability and lead to premature drug activation in the bloodstream, raising safety concerns. Conversely, too long linkers hinder both assembly stability and activation efficiency within tumor cells, diminishing anti-tumor effectiveness. The optimal linker (C12) achieved the best balance, ensuring robust assembly stability and high activation efficiency, thereby enhancing anti-tumor efficacy while maintaining a favorable safety profile. This work underscores the significance of linker length in designing effective DPS NPs for cancer treatment.
Gastric cancer (GC) remains a major public health problem. Ursolic acid (UA) is reported to be effective in inhibiting GC; however, its low solubility and poor biocompatibility have greatly hindered its clinical application. Herein, an innovative reactive oxygen species (ROS)-sensitive UA dimeric prodrug is developed by coupling two UA molecules via a ROS-cleavable linkage, which can self-assemble into stable nanoparticles in the presence of surfactant. This new UA-based delivery system comprises the following major components: (I) dimeric prodrug inner core that can achieve high drug-loading (55%, w/w) and undergo rapid and selective conversion into intact drug molecules in response to ROS; (II) a polyethylene glycol (PEG) shell to improve colloid stability and extend blood circulation, and (III) surface-modified internalizing RGD (iRGD) to increase tumor targeting. Enhancement of the antitumor effect of this delivery system was demonstrated against GC tumors in vitro and in vivo. This novel approach offers the potential for clinical applications of UA.
Rational design of nanoparticulate drug delivery systems (nano-DDS) for efficient cancer therapy is still a challenge, restricted by poor drug loading, poor stability, and poor tumor selectivity. Here, we report that simple insertion of a trisulfide bond can turn doxorubicin homodimeric prodrugs into self-assembled nanoparticles with three benefits: high drug loading (67.24%, w/w), high self-assembly stability, and high tumor selectivity. Compared with disulfide and thioether bonds, the trisulfide bond effectively promotes the self-assembly ability of doxorubicin homodimeric prodrugs, thereby improving the colloidal stability and in vivo fate of prodrug nanoassemblies. The trisulfide bond also shows higher glutathione sensitivity compared to the conventional disulfide bond, and this sensitivity enables efficient tumor-specific drug release. Therefore, trisulfide bond–bridged prodrug nanoassemblies exhibit high selective cytotoxicity on tumor cells compared with normal cells, notably reducing the systemic toxicity of doxorubicin. Our findings provide new insights into the design of advanced redox-sensitive nano-DDS for cancer therapy.
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