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 doxorubicin-induced 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 mitochondria-associated 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.

Design, synthesis and biological evaluation of pyrazolo3,4-

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-

Antitumor efficacy of EDTA co-treatment with cisplatin in tumor-bearing mice

Ethylenediamine tetraacetic acid (EDTA) is used in various medical applications. The aim of this study is to investigate the antitumor efficacy of EDTA alone or with cisplatin (Cis). Fifty male albino mice were used to assess the median lethal dose (LD50) of EDTA via intraperitoneal (i.p) injection. To determine the antitumor activity, fifty female albino mice were divided into five groups as the following; Group 1 (Gp1) was negative control; (Gp2-5) inoculated i.p with 2×106 Ehrlich Ascites Carcinoma (EAC) cells/mouse. After one day, Gp3, Gp4 and Gp5 injected with Cis (2 mg/kg), EDTA (25 mg/kg) and Cis (2 mg/kg)/EDTA (25 mg/kg) for six days, respectively. At day 14, all groups were sacrificed to assess the tumor profile, liver enzymes (alanine transaminases and aspartate transaminases), kidney function (urea and creatinine) and electrolytes (Na+, K+ and Ca2+). The results showed that the i.p LD50 of EDTA was 250 mg/kg. Treatment with EDTA alone did not show any antitumor activity and did not interfere with the antitumor efficacy of Cis. Biochemical findings revealed that EDTA had mild toxicity on liver and kidneys functions. In summary, EDTA had no antitumor effect and did not alter the Cis efficacy.

Development, in vitro biocompatibility, and antitumor efficacy of acetic acid-modified Cordyceps sinensis polysaccharide nanoparticle drug delivery system

Docetaxel-loaded acetic acid conjugated Cordyceps sinensis polysaccharide (DTX-AA-CSP) nanoparticles were prepared through dialysis and their release rates in vitro, particle sizes, zeta potentials, drug loading capacities, and encapsulation efficiencies were characterized for the synthesis of AA-modified CSPs from traditional Chinese medicine Cordyceps sinensis (Berk.) Sacc. Then, the AA-modified CSPs were characterized by 1H-NMR and FT-IR. Furthermore, the biocompatibility of the delivery carrier (AA-CSP nanoparticles) was assessed on human umbilical vein endothelial cells. In vitro antitumor activity studies on DTX-AA-CSP nanoparticles were conducted on the human liver (HepG2) and colon cancer cells (SW480). The DTX-AA-CSP nanoparticles were spherical and had an average size of 98.91±0.29 nm and zeta potential within the −19.75±1.13 mV. The encapsulation efficiency and loading capacity were 80.95%±0.43% and 8.09%±0.04%, respectively. In vitro, DTX from the DTX-AA-CSP nanoparticles exhibited a sustained release, and the anticancer activities of DTX-AA-CSP nanoparticles against SW480 and HepG2 were significantly higher than those of marketed docetaxel injection (Taxotere®) in nearly all the tested concentrations. The AA-CSP nanoparticles showed good biocompatibility. This study provided a promising biocompatible delivery system for carrying antitumor drugs for cancer therapy

Preparation of Highly Water-soluble Platinum Antitumor Drugs and Evaluation of Antitumor Efficacy on Tumor Cell Lines / 中国药学杂志

OBJECTIVE: To design and synthesize a new kind of highly water-soluble platinum antitumor compounds, and then evaluate their cytotoxicity in order to confirm their antitumor efficacy. METHODS: Diamide-diiodide platinum was firstly synthesized from potassium chloroplatinate, which was then reacted with Ag2SO4 to obtain intermediate . Using disodium 2-amino-alkyl malonate or N-substituted amino alkyl malonate as the intermediate Ⅱ, the two intermediates reacted at 1∶1 molar ratio to obtain the target compound III in the presence of acid. RESULTS: A new class of platinum compounds were synthesized, which had much better water solubility than that of the existing three-generation platinum compounds. Their antitumor efficacy was confirmed against a variety of tumor cell lines which was higher than that of carboplatin. IIIg was similar to cisplatin in antitumor efficacy on some tumor cell lines. Some target compounds were effective against cisplatin-resistant cell lines. CONCLUSION: Currently in the clinical trial, the target compound IIIg is a new platinum-base antitumor candidate, which exhibits good water solubility and antitumor efficacy in vitro, and the LD50 based on mice shows its lower toxicity than that of cisplatin and carboplatin in vivo.

Redox-sensitive prodrug nanoassemblies based on linoleic acid-modified docetaxel to resist breast cancers

Prodrug nanoassemblies, which can refrain from large excipients, achieve higher drug loading and control drug release, have been placed as the priority in drug delivery system. Reasoning that glutathione (GSH) and reactive oxygen species (ROS) are highly upgraded in tumor tissues which makes them attractive targets for drug delivery system, we designed and synthetized a novel prodrug which utilized mono thioether bond as a linker to bridge linoleic acid (LA) and docetaxel (DTX). This mono thioether-linked conjugates (DTX-S-LA) could self-assemble into nanoparticles without the aid of much excipients. The mono thioether endowed the nanoparticles redox sensitivity resulting in specific release at the tumor tissue. Our studies demonstrated that the nanoassemblies had uniform particle size, high stability and fast release behavior. DTX-S-LA nanoassemblies outperformed DTX solution in pharmacokinetic profiles for it had longer circulation time and higher area under curve (AUC). Compared with DTX solution, the redox dual-responsive nanoassemblies had comparable cytotoxic activity. Besides, the antitumor efficacy was evaluated in mice bearing 4T1 xenograft. It turned out this nanoassemblies could enhance anticancer efficacy by increasing the dose because of higher tolerance. Overall, these results indicated that the redox sensitivity nanoassemblies may have a great potential to cancer therapy.

Improved Antitumor Efficacy of Hyaluronic Acid-Complexed Paclitaxel Nanoemulsions in Treating Non-Small Cell Lung Cancer

Paclitaxel (PTX) is a effectively chemotherapeutic agent which is extensively able to treat the non-small cell lung, pancreatic, breast and other cancers. But it is a practically insoluble drug with water solubility less than 1 μg/mL, which restricts its therapeutic application. To overcome the problem, hyaluronic acid-complexed paclitaxel nanoemulsions (HPNs) were prepared by ionic complexation of paclitaxel (PTX) nanoemulsions and hyaluronic acid (HA) to specifically target non-small cell lung cancer. HPNs were composed of dl-α-tocopheryl acetate, soybean oil, polysorbate 80, ferric chloride, and HA and fabricated by high-pressure homogenization. The HPNs were 85.2 ± 7.55 nm in diameter and had a zeta potential of −35.7 ± 0.25 mV. The encapsulation efficiency was almost 100%, and the PTX content was 3.0 mg/mL. We assessed the in vivo antitumor efficacy of the HPNs by measuring changes in tumor volume and body weight in nude mice transplanted with CD44-overexpressing NCI-H460 xenografts and treated with a bolus dose of saline, Taxol®, PTX nanoemulsions (PNs), or HPNs at a dose of 25 mg/kg. Suppression of cancer cell growth was higher in the PN- and HPN-treated groups than in the Taxol® group. In particular, HPN treatment dramatically inhibited tumor growth, likely because of the specific tumor-targeting affinity of HA for CD44-overexpressed cancer cells. The loss of body weight and organ weight did not vary significantly between the groups. It is suggest that HPNs should be used to effective nanocarrier system for targeting delivery of non-small cell lung cancer overexpressing CD44 and high solubilization of poorly soluble drug.