Fine-tuning the structure-tolerance-antitumor efficacy axis of prodrug nanoassemblies via branched aliphatic functionalization

Small-molecule prodrug nanoassemblies have emerged as efficient antitumor drug delivery systems.However,in the case of camptothecins-based prodrug nanoassemblies,linear aliphatic side chain modification often results in rod-shaped or irregularly shaped nanoassemblies,which are highly unfavorable for sterilization through filtration,and may cause capillary blockage upon intravenous injection.The rational design of camptothecins-based prodrug nanoassemblies remains a challenge.Herein,we propose that branched aliphatic alcohol(BAA)functionalization could fine-tune the structure-tolerance-antitumor efficacy axis of prodrug nanoassemblies.Correspondingly,four SN38-BAA prodrugs were synthesized by conjugating 7-ethyl-10-hydroxycamptothecin(SN38)with BAAs of varying lengths via a tumor redox-responsive disulfide bond,which self-assemble into uniform spherical nanoparticles.The length of BAA was found to significant impact the multiple drug delivery process,including colloidal stability,drug release profiles and pharmacokinetics.Overall,SN38-C21 NPs(SN38-11-heneicosanol nanoparticles),featuring the longest BAA,showcased multiple therapeutic advantages,ultimately culminating the optimal antitumor efficacy and tolerance.The findings underscore the potential of BAA functionalization in strengthening the therapeutic outcomes of prodrug nanoassemblies,and provide valuable insights for developing translational camptothecins-based nanomedicines.

In vitro and in vivo antitumor efficacy of CLA-PTX on B16-F10 melanoma cells

The purpose of this study was to investigate the potential antitumor efficacy of conjugated linoleic acid-paclitaxel （CLA-PTX） on B16-F10 melanoma cell line in vitro and in vivo. The in vitro cytotoxicity, apoptosis and cell cycle of CLA-PTX were investigated. The in vitro cellular uptake of CLA-PTX in B16-F10 cells was also analyzed. The antitumor activity of CLA-PTX was also evaluated in B16-F10 tumor-bearing C57BL6/N mice in vivo. The in vitro cytotoxicity results showed that the IC50 of the CLA-PTX is （4.25±0.43） μM, compared with that of （6.70±0.80） μM in PTX treatment group （P〈0.01）. CLA-PTX increased the percentage of total apoptotic cells compared with that of control and PTX treatment groups （P〈0.01）. Compared with untreated cells, CLA-PTX arrested cell cycle progression at the S phase, whereas PTX caused accumulation of cell at GE-M phase both along with the reduction of the cellular fraction arrested at the G1 phase. The amount of cellular uptake of CLA-PTX was significantly higher than that of PTX （P〈0.01）. The in vivo antitumor activity of CLA-PTX was significantly higher than that of control and PTX treatment groups （P〈0.01 or P〈0.05）. In conclusion, our study demonstrated that CLA-PTX has significant antitumor activity in B 16-F 10 cell line.

Antitumor efficacy of doxorubicin encapsulated in neovasculature targeting liposomes

It was reported that a 5-amino acid peptide Ala-Pro-Arg-Pro-Gly （APRPG） could specifically bind to the tumor angiogenic site. We investigated the antitumor efficacy of doxorubicin （DOX） encapsulated in APRPG modified liposome （APRPG-LP） compared with DOX encapsulated in non-APRPG modified liposomes （LP） and DOX solution （flee DOX） on Lewis lung carcinoma （LLC） bearing mice. APRPG-LP could efficiently suppress the tumor growth of the experimental mice, compared with LP （P〈0.001）, free DOX （P〈0.001） and saline of negative control （P〈0.001）. The present results demonstrated that the APRPG modified liposomes exhibited a much better therapeutic efficacy over the non-modified liposomes and the DOX solution, because of the effect of targeted tumor angiogenesis disruption. Thus, APRPG-LP could be a promising active-targeting drug carrier to tumor angiogenic site.

Overexpressed SIRT6 ameliorates doxorubicin-induced cardiotoxicity and potentiates the therapeutic efficacy through metabolic remodeling

Since the utilization of anthracyclines in cancer therapy, severe cardiotoxicity has become a major obstacle. The major challenge in treating cancer patients with anthracyclines is minimizing cardiotoxicity without compromising antitumor efficacy. Herein, histone deacetylase SIRT6 expression was reduced in plasma of patients treated with anthracyclines-based chemotherapy regimens. Furthermore,overexpression of SIRT6 alleviated doxorubicin-induced cytotoxicity in cardiomyocytes, and potentiated cytotoxicity of doxorubicin in multiple cancer cell lines. Moreover, SIRT6 overexpression ameliorated doxorubicin-induced cardiotoxicity and potentiated antitumor efficacy of doxorubicin in mice, suggesting that SIRT6 overexpression could be an adjunctive therapeutic strategy during doxorubicin treatment.Mechanistically, doxorubicin-impaired mitochondria led to decreased mitochondrial respiration and ATP production. And SIRT6 enhanced mitochondrial biogenesis and mitophagy by deacetylating and inhibiting Sgk1. Thus, SIRT6 overexpression coordinated metabolic remodeling from glycolysis to mitochondrial respiration during doxorubicin treatment, which was more conducive to cardiomyocyte metabolism, thus protecting cardiomyocytes but not cancer cells against doxorubicin-induced energy deficiency. In addition, ellagic acid, a natural compound that activates SIRT6, alleviated doxorubicininduced cardiotoxicity and enhanced doxorubicin-mediated tumor regression in tumor-bearing mice.These findings provide a preclinical rationale for preventing cardiotoxicity by activating SIRT6 in cancer patients undergoing chemotherapy, but also advancing the understanding of the crucial role of SIRT6 in mitochondrial homeostasis.

Stimuli-responsive nano vehicle enhances cancer immunotherapy by coordinating mitochondria-targeted immunogenic cell death and PD-L1 blockade

Induction of immunogenic cell death promotes antitumor immunity against cancer. However, majority of clinically-approved drugs are unable to elicit sufficient ICD. Here, our study revealed that mitochondria-targeted delivery of doxorubicin(DOX) massively amplified ICD via substantial generation of reactive oxygen species(ROS) after mitochondrial damage. The underlying mechanism behind increased ICD was further demonstrated to be ascribed to two pathways:(1) ROS elevated endoplasmic reticulum(ER) stress, leading to surface exposure of calreticulin;(2) ROS promoted release of various mitochondriaassociated damage molecules including mitochondrial transcription factor A. Nevertheless, adaptive upregulation of PD-L1 was found after such ICD-inducing treatment. To overcome such immunosuppressive feedback,we developed a tumor stimuli-responsive nano vehicle to simultaneously exert mitochondrial targeted ICD induction and PD-L1 blockade. The nano vehicle was self-assembled from ICD-inducing copolymer and PD-L1 blocking copolymer, and possessed long-circulating property which contributed to better tumor accumulation and mitochondrial targeting. As a result, the nano vehicle remarkably activated antitumor immune responses and exhibited robust antitumor efficacy in both immunogenic and non-immunogenic tumor mouse models.

Effects of gold core size on regulating the performance of doxorubicin-conjugated gold nanoparticles

Studies on the influence of one critical parameter （e.g., size）, targeting a specific disease, while keeping other factors unchanged, are important for improving understanding and application of the molecular design of biomedical nanomaterials. In this study, we used doxorubicin （Dox）-conjugated gold nanoparticles （GNPs） to investigate the effects of the size of the gold core （10, 20, or 60 nm） on the performance of their conjugates. We found that all three conjugates differed slightly in their physicochemical properties, facilitating a direct and accurate assessment of the size effects of GNP-Dox conjugates on their in vitro and in vivo performance. The cytological properties （the cell penetration rate and efficiency, as well as the cytotoxicity） and antitumor performance （the intratumoral penetration, treatment efficacy, and biodistribution） were highly correlated to the size of the inorganic core. Among all test groups, although the conjugate with a 60-nm gold core had the highest drug loading and release efficiency, the conjugate with a 10-nm gold core displayed the best antitumor efficacy toward the liver cancer models. This was because it showed the deepest tumor permeability and the highest tumor cell-killing ability of Dox transported by the relatively small GNPs. This study provides important evidence for better understanding the effect of size on in vitro and in vivo properties of potential therapeutic nanosystems and their structure design.

Design, synthesis and biological evaluation of pyrazolo[3,4-d]pyridazinone derivatives as covalent FGFR inhibitors

Fibroblast growth factor receptors (FGFRs) have emerged as promising targets for anticancer therapy.In this study,we synthesized and evaluated the biological activity of 66 pyrazolo[3,4-d]pyridazinone derivatives.Kinase inhibition,cell proliferation,and whole blood stability assays were used to evaluate their activity on FGFR,allowing us to explore structureàactivity relationships and thus to gain understanding of the structural requirements to modulate covalent inhibitors’selectivity and reactivity.Among them,compound 10h exhibited potent enzymatic activity against FGFR and remarkably inhibited proliferation of various cancer cells associated with FGFR dysregulation,and suppressed FGFR signaling pathway in cancer cells by the immunoblot analysis.Moreover,10h displayed highly potent antitumor efficacy (TGI Z 91.6%,at a dose of 50 mg/kg) in the FGFR1-amplified NCI-H1581 xenograft model.