Isoginkgetin-loaded reactive oxygen species scavenging nanoparticles ameliorate intervertebral disc degeneration via enhancing autophagy in nucleus pulposus cells.

Excessive reactive oxygen species (ROS) in nucleus pulposus cells (NPCs) promote extracellular matrix (ECM) degradation and cellular inflammatory responses by activating a variety of cellular pathways, ultimately inducing cell apoptosis and leading to the development of low back pain. Here, we designed and fabricated an isoginkgetin-loaded ROS-responsive delivery system (IGK@SeNP) based on diselenide block copolymers. Successfully encapsulated IGK was released intelligently and rapidly in a microenvironment with high ROS levels in degenerative disc. Controlled-release IGK not only efficiently scavenged ROS from the intervertebral disc together with diselenide block copolymers but also effectively enhanced autophagy in NPCs to inhibit ECM degradation and cell apoptosis, and showed significant therapeutic effects in the rat intervertebral disc degeneration (IDD) model. Overall, the synergistic effects of IGK@SeNP in ROS scavenging and autophagy enhancement endowed it with an attractive therapeutic strategy for IDD treatment.

Co-delivery of photosensitizer and diclofenac through sequentially responsive bilirubin nanocarriers for combating hypoxic tumors.

Considering that photodynamic therapy (PDT)-induced oxygen consumption and microvascular damage could exacerbate hypoxia to drive more glycolysis and angiogenesis, a novel approach to potentiate PDT and overcome the resistances of hypoxia is avidly needed. Herein, morpholine-modified PEGylated bilirubin was proposed to co-deliver chlorin e6, a photosensitizer, and diclofenac (Dc). In acidic milieu, the presence of morpholine could enable the nanocarriers to selectively accumulate in tumor cells, while PDT-generated reactive oxidative species (ROS) resulted in the collapse of bilirubin nanoparticles and rapid release of Dc. Combining with Dc showed a higher rate of apoptosis over PDT alone and simultaneously triggered a domino effect, including blocking the activity and expression of lactate dehydrogenase A (LDHA), interfering with lactate secretion, suppressing the activation of various angiogenic factors and thus obviating hypoxia-induced resistance-glycolysis and angiogenesis. In addition, inhibition of hypoxia-inducible factor-1α (HIF-1α) by Dc alleviated hypoxia-induced resistance. This study offered a sequentially responsive platform to achieve sufficient tumor enrichment, on-demand drug release and superior anti-tumor outcomes in vitro and in vivo.

Co-delivery of photosensitizer and diclofenac through sequentially responsive bilirubin nanocarriers for combating hypoxic tumors

Considering that photodynamic therapy (PDT)-induced oxygen consumption and microvascular damage could exacerbate hypoxia to drive more glycolysis and angiogenesis, a novel approach to potentiate PDT and overcome the resistances of hypoxia is avidly needed. Herein, morpholine-modified PEGylated bilirubin was proposed to co-deliver chlorin e6, a photosensitizer, and diclofenac (Dc). In acidic milieu, the presence of morpholine could enable the nanocarriers to selectively accumulate in tumor cells, while PDT-generated reactive oxidative species (ROS) resulted in the collapse of bilirubin nanoparticles and rapid release of Dc. Combining with Dc showed a higher rate of apoptosis over PDT alone and simultaneously triggered a domino effect, including blocking the activity and expression of lactate dehydrogenase A (LDHA), interfering with lactate secretion, suppressing the activation of various angiogenic factors and thus obviating hypoxia-induced resistance-glycolysis and angiogenesis. In addition, inhibition of hypoxia-inducible factor-1α (HIF-1α) by Dc alleviated hypoxia-induced resistance. This study offered a sequentially responsive platform to achieve sufficient tumor enrichment, on-demand drug release and superior anti-tumor outcomes in vitro and in vivo.

Self-Delivered and Self-Monitored Chemo-Photodynamic Nanoparticles with Light-Triggered Synergistic Antitumor Therapies by Downregulation of HIF-1α and Depletion of GSH.

Photodynamic therapy (PDT), a clinically approved cancer treatment, has faced many drawbacks that restricted its applications. For example, the hypoxia-induced elevated hypoxia-inducible factor-1α (HIF-1α) may desensitize tumors to PDT, and the high concentration of glutathione (GSH) in cancer cells can also neutralize the generated reactive oxygen species (ROS) during PDT, resulting in insufficient therapy. Moreover, extra probes for imaging-guided visualization therapy are always needed to track drug release or distribution, while it may decrease the drug loading of the drug delivery system (DDS). In the present study, we have designed and prepared a novel multifunctional combined therapy nanoparticle (ZnPc@Cur-S-OA NPs), in which curcumin (Cur) was not only used as a chemotherapy drug to achieve a combination therapy with PDT via downregulating HIF-1α and depleting GSH in B16F10 cells but also designed as a small-molecule ROS-triggered release prodrug to deliver the photosensitizer (PS). The red fluorescence of PS in the nanoparticles (NPs) can be used to track the NPs distribution, while the green fluorescence of Cur showed an "OFF-ON" activation, which enables additional imaging and real-time self-monitoring capabilities. These results proved that the prepared combined therapy NPs were more effective to inhibit the growth of B16F10 mouse melanoma tumor than was monotherapy without eliciting systemic toxicity either in vitro or in vivo, which indicated the combined therapy NPs as an effective way to improve the PDT efficacy via downregulation of HIF-1α and depletion of GSH. Thus, the strategy of using a multifunctional natural product as the stimuli-responsive carrier as well as the synergist with PDT for enhancing antitumor efficacy via multiple pathways may open an alternative avenue to fabricate new self-delivery combination therapy nanodrugs. Besides, the fluorescence emitted from the drug can be used for real-time self-monitoring of drug release and distribution, which has great potential in clinic to adjust the administration dose and irradiation time for different tumor types and stages for individual therapy.