Synthesis and biological evaluation of norcantharidin derivatives as protein phosphatase-1 inhibitors

Lactoferrin-functionalized PEGylation liposomes loaded with norcantharidin acid for targeted therapy of hepatocellular carcinoma

Norcantharidin (NCTD), an antitumor agent with an increased leukocyte function, has been used for the treatment of hepatocellular carcinoma (HCC) in clinical. However, the clinical application of NCTD is limited due to its inadequate hydrophilicity and lipophilicity, short half-life (t1/2), as well as adverse effects such as vascular irritation, cardiotoxicity, and nephrotoxicity. Herein, a lactoferrin (Lf) and DSPE-mPEG2000 functionalized liposomes loaded with norcantharidic acid (NCA), an active metabolite of NCTD, was constructed for the targeted therapy of HCC. In this study, blank PEGylated liposomes were prepared using the film hydration method, and the NCA was loaded by calcium acetate active loading method to increase the encapsulation efficiency (EE). Subsequently, lactoferrin was covalently coupled to DSPE-PEG2000-COOH activated by EDC and NHS. In addition, the in vivo pharmacokinetics and pharmacodynamics were investigated in Sprague-Dawley (SD) rats and H22 tumor-bearing BALB/c mice, respectively. As expected, the encapsulation efficiency measurement showed that the encapsulation efficiency of the NCA liposomes was 89.3±1.25 %, and the coupling efficiency of lactoferrin was more than 65.97 %. Additionally, the variations in both the dynamic size and encapsulation efficiency of norcantharidic acid liposomes in long-term storage stability and serum stability studies did not exceed 10 %. Furthermore, the pharmacokinetics and pharmacodynamics results showed that, the NCA-Lips-Lf were able to significantly improve antitumor activity by enhancing tumor-targeting accumulation and prolonging circulation time in the body compared to the sodium demethylcantharidate for injection (Na2DCA). Notably, the AUC0-48 and the t1/2 of NCA-Lips-Lf increased 4.28-time and 5.17-time in comparison to those of NCA-sol, respectively. The tumor inhibition rate of NCA-Lips-Lf (85.29 %) was significantly higher than that of sodium demethylcantharidate for injection (Na2DCA) (59.13 %), without obvious vascular irritation, cardiotoxicity and nephrotoxicity. In conclusion, NCA-Lips-Lf have the potential to eliminate hepatocellular carcinoma more effectively with fewer side effects than Na2DCA, which further advances the clinical application of norcantharidin-related drugs.

Nanoemulsion based lipid nanoparticles for effective demethylcantharidin delivery to cure liver cancer

Demethylcantharidin (DEM) is a widely used antitumor drug; however, its poor tumor targeting and serious organotoxicity limit its application. The aim of this study was to develop a new drug delivery system for efficient delivery of DEM. Nanoemulsion based lipid nanoparticles containing demethylcantharidin (DNLNs) were prepared by loading nanoemulsions into lipid nanoparticles. The cells proliferation, apoptosis, cycle, and uptake were investigated by Cell counting kit-8 (CCK-8), flow cytometry, and in situ fluorescence assays, respectively. Then, we established the H22 tumor-bearing mouse model to evaluate the antitumor efficacy of DNLNs and further studied its organ toxicity and distribution. DNLNs significantly inhibited the proliferation and promoted apoptosis of H22 cells, and H22 cells could take up more DNLNs. Compared with DEM, DNLNs had certain tumor-targeting properties, and the tumor inhibition rate increased by 23.24%. Moreover, DNLNs can increase white blood cell count and reduce organ toxicity. This study paves the way for nanoemulsion-based lipid nanoparticle (NLNs)-efficient DEM delivery to treat liver cancer.

Selective N-Alkylation of Aminobenzenesulfonamides with Alcohols for the Synthesis of Amino-(N-alkyl)benzenesulfonamides Catalyzed by a Metal-Ligand Bifunctional Ruthenium Catalyst

[(p-Cymene)Ru(2,2'-bpyO)(H2O)] was proven to be an efficient catalyst for the synthesis of amino-(N-alkyl)benzenesulfonamides via selective N-alkylation of aminobenzenesulfonamides with alcohols. It was confirmed that functional groups in the bpy ligand are crucial for the activity of catalysts. Furthermore, the utilization of this catalytic system for the preparation of a biologically active compound was presented.

Liposomal Nanodrug Based on Norcantharidin Derivative for Increased in Vivo Activity

To address the limitations of norcantharidin (NCTD) in clinical applications, including restricted tumor accumulation and intense irritation, we have developed a new derivative of NCTD with (S)-1-benzyl-3-pyrrolidinol, which can be actively loaded into liposomes to achieve drug encapsulation and sustained release properties by using pH gradient loading technique. Cytotoxicity tests against cancer cell lines (Hepa 1-6 and 4 T1 cells) have demonstrated that this derivative exhibits comparable activity to NCTD in vitro. The NCTD derivative can be efficiently loaded into liposomes with high encapsulation efficiency (98.7%) and high drug loading (32.86%). Tolerability and antitumor efficacy studies showed that the liposomal NCTD derivative was well tolerated at intravenous injection doses of 3 folds higher than the parent drug solution, while significantly improved anticancer activity in vivo was achieved. This liposomal nanodrug could become a potent and safe NCTD formulation alternative for cancer therapy.

Strategies for Solubility and Bioavailability Enhancement and Toxicity Reduction of Norcantharidin

Cantharidin (CTD) is the main active ingredient isolated from Mylabris, and norcantharidin (NCTD) is a demethylated derivative of CTD, which has similar antitumor activity to CTD and lower toxicity than CTD. However, the clinical use of NCTD is limited due to its poor solubility, low bioavailability, and toxic effects on normal cells. To overcome these shortcomings, researchers have explored a number of strategies, such as chemical structural modifications, microsphere dispersion systems, and nanodrug delivery systems. This review summarizes the structure-activity relationship of NCTD and novel strategies to improve the solubility and bioavailability of NCTD as well as reduce the toxicity. This review can provide evidence for further research of NCTD.

Preclinical evaluations of Norcantharidin liposome and emulsion hybrid delivery system with improved encapsulation efficiency and enhanced antitumor activity

BACKGROUND

Norcantharidin (NCTD) has a certain degree of hydrophilicity and poor lipophilicity, and has some side-effects, including short t_1/2, vascular irritation, cardiotoxicity and nephrotoxicity, which bring difficulties for formulation research. In this study, we aim to develop a novel nanocarrier to improve encapsulation efficiency, increase sterilization stability and enhance antitumor activity.

METHODS

Phospholipid complexes methods were used for increasing the lipophilicity of norcantharidin (NCTD), then NCTD phospholipid complexes were not only loaded in the oil phase and oil-water interface surface, but also encapsulated in phospholipid bilayers to obtain NCTD liposome-emulsion hybrid (NLEH) delivery system. The in vitro cytotoxicity and apoptosis, in vivo tissue distribution, tumor penetration, heterotopic and orthotopic antitumor studies were conducted to evaluate therapeutic effect.

RESULTS

NLEH exhibited an improved encapsulation efficiency (89.3%) and a better sterilization stability, compared to NCTD liposomes and NCTD emulsions. NLEH can achieve a better antitumor activity by promoting absorption (1.93-fold), prolonging blood circulation (2.08-fold), enhancing tumor-targeting accumulation (1.19 times), improving tumor penetration, and increasing antitumor immunity.

CONCLUSIONS

The liposome-emulsion hybrid (LEH) delivery system was potential carrier for NCTD delivery, and LEH could open opportunities for delivery of poorly soluble anticancer drugs, especially drugs that are more hydrophilicity than lipophilicity.

Norcantharidin: research advances in pharmaceutical activities and derivatives in recent years

Cantharidin (CTD) is the main bioactive component of Cantharides, which is called Banmao in Traditional Chinese Medicine (TCM). Norcantharidin (NCTD) is a structural modifier of CTD. To compare with CTD, NCTD has lighter side effects and stronger bioactivity in anti-cancer through inhibiting cell proliferation, causing apoptosis and autophagy, overwhelming migration and metastasis, affecting immunity as well as lymphangiogenesis. Examples of these effects include suppressing Protein Phosphatase 2A and modulating Wnt/beta catenin signal, with Caspase family proteins, AMPK pathway and c-Met/EGFR pathway involving respectively. Moreover, NCTD has the effects of immune enhancement, anti-platelet aggregation and inhibition of renal interstitial fibrosis with distinct signaling pathways. The immunological effects induced by NCTD are related to the regulation of macrophage polarization and LPS-mediated immune response. The antiplatelet activity that NCTD induced is relevant to the inhibition of platelet signaling and the downregulation of α2 integrin. Furthermore, some of novel derivatives designed and synthesized artificially show stronger biological activities (e.g., anticancer effect, enzyme inhibition effect, antioxidant effect) and lower toxicity than NCTD itself. Plenty of literatures have reported various pharmacological effects of NCTD, particularly the anticancer effect, which has been widely concerned in clinical application and laboratory research. In this review, the pharmaceutical activities and derivatives of NCTD are discussed, which can be reference for further study.

Clinical efficacy and safety of aidi injection combination with vinorelbine and cisplatin for advanced non-small-cell lung carcinoma: A systematic review and meta-analysis of 54 randomized controlled trials

The Aidi injection contains multiple active ingredients, including astragaloside (Re, Rb1, and Rg1), ginsenoside, cantharidin, elentheroside E, and syringin, and it is administered with vinorelbine and cisplatin (NP) to treat non-small-cell lung carcinoma (NSCLC). In this study, we performed a systematic review and meta-analysis to determine the clinical efficacy and safety of the Aidi injection with NP, and the optimal threshold and treatment regimen to produce the desired responses. We collected all studies regarding the Aidi injection with NP for NSCLC from Chinese and English databases (up to April 2019). Risk of methodological bias was evaluated for each study. Data for analysis were extracted using a standard data extraction form. Evidence quality was assessed following the Grading of Recommendations Assessment, Development and Evaluation approach. We included 54 trials containing 4,053 patients for analysis. Combining the Aidi injection with NP significantly increased the objective response rate (odds ratio [OR], 1.32; confidence interval [CI], 1.23, 1.42), disease control rate (OR, 1.14; CI, 1.11, 1.18), and quality of life (OR, 1.80; CI, 1.61, 1.98), with decreased risks of myelosuppression, neutropenia, thrombocytopenia, anemia, gastrointestinal reaction, and liver dysfunction. For patients with a Karnofsky Performance Status score of ≥60, the Aidi injection (50 mL/day, two weeks/cycle, with two to three cycles) treatment with vinorelbine (25 mg/m²) and cisplatin (30-35 mg/m² or 40-50 mg/m²) might be the optimal regimen for producing the desired tumor response and achieving a good safety level. Most results were robust, and their quality was moderate. The results suggest that administration of the Aidi injection and concomitant NP is beneficial to NSCLC, and provide evidence for the optimal threshold and treatment regimen that may improve tumor response with a good safety level.

Studies on anti-hepatocarcinoma effect, pharmacokinetics and tissue distribution of carboxymethyl chitosan based norcantharidin conjugates

Aiming to enhance therapeutic efficiency and reduce toxic effect of norcantharidin (NCTD), NCTD-conjugated carboxymethyl chitosan (CMCS) conjugates (CNC) were prepared and evaluated for the treatment of hepatocellular carcinoma. In vitro cellular assays revealed that CNC conjugates possessed potent inhibitory effects on the proliferation and migration of BEL-7402 cells. Besides, CNC could change nuclear morphology of tumor cells. In comparison with free NCTD at equivalent dose, CNC exerted enhanced therapeutic efficiency and diminished systemic toxicity in H22 tumor-bearing mice with a tumor inhibition rate of 56.20%. Further investigation about pharmacokinetics and tissue distribution by high performance liquid chromatography (HPLC) analysis indicated that CNC showed a longer retention time in blood circulation and reduced distribution in heart and kidney tissues, thereby exerting different antitumor efficacy and toxicity compared with free NCTD. Our results suggested that CNC conjugates based on CMCS as polymer carriers might be used as a potential clinical alternative for NCTD in tumor therapy.

Clinical efficacy and safety of Aidi injection plus paclitaxel-based chemotherapy for advanced non-small cell lung cancer: A meta-analysis of 31 randomized controlled trials following the PRISMA guidelines

ETHNOPHARMACOLOGICAL RELEVANCE

As an important Chinese herb injection, Aidi injection is composed of the extracts from Astragalus, Eleutherococcus senticosus, Ginseng, and Cantharis. Aidi injection plus paclitaxel-based chemotherapy is often used to in the treatment of non-small cell lung cancer (NSCLC) in China.

AIM OF THE STUDY

The objective of this study is to further confirm whether Aidi injection can improve the tumor responses and survivals, and reveal its safety, optimal usage and combination with paclitaxel.

MATERIALS AND METHODS

A meta-analysis was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All randomized controlled trials (RCTs) concerning the Aidi injection plus paclitaxel-based chemotherapy for NSCLC were selected. Main outcomes were objective response rate (ORR), disease control rate (DCR), survivals, quality of life (QOL) and adverse drug reactions (ADRs). All data were extracted by using a standard data extraction form and synthesized through meta-analysis. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used for rating the quality of evidence.

RESULTS

Thirty-one RCTs involving 2058 patients were included, and most trials had an unclear methodological bias risk. The risk ratio (RR) and 95% confidence intervals (CI) of ORR, DCR, QOL, neutropenia, thrombocytopenia, gastrointestinal toxicity and liver injury were as following: 1.32 (1.20-1.46), 1.14 (1.09-1.20), 1.89 (1.66-2.16), 0.61 (0.51-0.74), 0.62 (0.45-0.87), 0.59 (0.49-0.72) and 0.52 (0.36-0.75). Compared to chemotherapy alone, all differences were statistically significant. Subgroup analysis showed that only with the TP, Aidi injection could increase the ORR and DCR. Treatment with 100 ml, 80 ml or 50 ml/time, and 14 days/2 cycles or 21 days/2-4 cycles, Aidi injection could increase the ORR and DCR, respectively. Sensitivity analysis showed that the results had good robustness. None of the trials reported the overall survivals (OS), progression free survival (PFS). The quality of evidences was moderate.

CONCLUSIONS

Current moderate evidence revealed that Aidi injection plus paclitaxel-based chemotherapy, especially TP can significantly improve the clinical efficacy and QOL for patients with stage III/IV NSCLC. Aidi injection can relieve the risk of hematotoxicity, gastrointestinal toxicity and liver injury in patient with NSCLC receiving paclitaxel-based chemotherapy. The optimal usage may be 50 ml/time and 14 days/2 cycles.

Syntheses, crystal structures and DNA-binding activities of divalent Fe, Cu, Zn and Cd complexes with 4′-(furan-2-yl)-2,2′:6′,2″-terpyridine

Five coordination complexes [Fe(ftpy)2](ClO4)2·(H2O)2 (1), [Cu(ftpy)(NO3)(H2O)](NO3) (2), [Cu(ftpy)2]2(ClO4)4·(C2H5OH) (3), [Zn(ftpy)2]·(ClO4)2·(H2O)1.5 (4) and [Cd(ftpy)2]2(ClO4)4·(C2H5OH) (5) (ftpy=4′-(furan-2-yl)-2,2′:6′,2′-terpyridine) have been synthesized and characterized by IR, elemental analysis and single-crystal X-ray diffraction. With the exception of 4, all complexes adopt normal homoleptic [M(ftpy)2]2+ motifs. In the crystal, both hydrogen bonds and face-to-face interactions between furyl and pyridyl rings facilitate the construction of three-dimensional networks. The DNA-binding activities of the five complexes have been investigated by fluorescence emission titration at room temperature suggesting an intercalative mode for 1–3 with a relative order, 3>2>1, and a combined static and dynamic mode for 4 and 5.

Insects: an underrepresented resource for the discovery of biologically active natural products

Nature has been the source of life-changing and -saving medications for centuries. Aspirin, penicillin and morphine are prime examples of Nature׳s gifts to medicine. These discoveries catalyzed the field of natural product drug discovery which has mostly focused on plants. However, insects have more than twice the number of species and entomotherapy has been in practice for as long as and often in conjunction with medicinal plants and is an important alternative to modern medicine in many parts of the world. Herein, an overview of current traditional medicinal applications of insects and characterization of isolated biologically active molecules starting from approximately 2010 is presented. Insect natural products reviewed were isolated from ants, bees, wasps, beetles, cockroaches, termites, flies, true bugs, moths and more. Biological activities of these natural products from insects include antimicrobial, antifungal, antiviral, anticancer, antioxidant, anti-inflammatory and immunomodulatory effects.

Cytotoxicity of a Series of Norcantharidin-Inspired Tetrahydroepoxyisoindole Carboxamides

A series of 28 norcantharidin (NorC)-inspired analogues were accessed via a robust two-step Ugi intramolecular Diels-Alder (IMDA) sequence. Four analogues displayed whole-cell cytotoxicity equipotent to that of NorC and cisplatin against a number of cancer cell lines and a normal breast cell line (MCF10A). Notably, (3S,3aS,6R)-2-benzyl-7-methyl-N-(naphthalen-2-yl)-1-oxo-1,2,3,6-tetrahydro-3a,6-epoxyisoindole-3-carboxamide (trans-27) displayed superior whole-cell activity against breast (MCF-7, GI₅₀ =2.9 μm) and colon (HT29, GI₅₀ =6.4 μm) cancer cell lines relative to the control (cisplatin), which elicited respective GI₅₀ values of 6.5 and 11.3 μm against the aforementioned cell lines. This analogue also displayed improved activity relative to NorC across the breast (MCF-7, GI₅₀ =2.9 μm; NorC GI₅₀ =7.5 μm), ovarian (A2780, GI₅₀ =2.2 μm; NorC GI₅₀ =4.4 μm), and neuroblastoma (BE2-C, GI₅₀ =2.2 μm; NorC GI₅₀ =3.7 μm) cancer cell lines. Structure-activity relationship (SAR) investigations demonstrated that retention of sp² hybridized connections within the tetrahydroepoxyisoindole carboxamide scaffold is crucial, as aromatization to a phenolic functionality decreased activity, whereas removal of a single olefin bond abolished cytotoxicity. Nonetheless, with respect to the latter, use of crotonic acid as opposed 2-butynoic acid in the Ugi-IMDA sequence imparted a significant improvement to diastereoselectivity, with the cis/trans isomer ratio shifting from ≈1:1.2 to ≈0.5:9.5.

Synthesis of a norcantharidin-tethered guanosine: Protein phosphatase-1 inhibitors that change alternative splicing

Phosphorylation and dephosphorylation of splicing factors play a key role in pre-mRNA splicing events, and cantharidin and norcantharidin analogs inhibit protein phosphatase-1 (PP1) and change alternative pre-mRNA splicing. Targeted inhibitors capable of selectively inhibiting PP-1 could promote exon 7 inclusion in the survival-of-motorneuron-2 gene (SMN2) and shift the proportion of SMN2 protein from a dysfunctional to a functional form. As a prelude to the development of norcantharidin-tethered oligonucleotide inhibitors, the synthesis a norcantharidin-tethered guanosine was developed in which a suitable tether prevented the undesired cyclization of norcantharidin monoamides to imides and possessed a secondary amine terminus suited to the synthesis of oligonucleotides analogs. Application of this methodology led to the synthesis of a diastereomeric mixture of norcantharidin-tethered guanosines, namely bisammonium (1R,2S,3R,4S)- and (1S,2R,3S,4R)-3-((4-(2-(((((2R,3R,4R,5R)-5-(2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)-2-(hydroxymethyl)-4-methoxytetrahydrofuran-3-yl)oxy)oxidophosphoryl)oxy)ethyl)-phenethyl)(methyl)carbamoyl)-7-oxabicyclo[2.2.1]heptane-2-carboxylate, which showed activity in an assay for SMN2 pre-mRNA splicing.