Determination and pharmacokinetic study of the diacid metabolite of norcantharidin in beagle plasma by use of liquid chromatography-tandem mass spectrometry

Review targeted drug delivery systems for norcantharidin in cancer therapy

Norcantharidin (NCTD) is a demethylated derivative of cantharidin (CTD), the main anticancer active ingredient isolated from traditional Chinese medicine Mylabris. NCTD has been approved by the State Food and Drug Administration for the treatment of various solid tumors, especially liver cancer. Although NCTD greatly reduces the toxicity of CTD, there is still a certain degree of urinary toxicity and organ toxicity, and the poor solubility, short half-life, fast metabolism, as well as high venous irritation and weak tumor targeting ability limit its widespread application in the clinic. To reduce its toxicity and improve its efficacy, design of targeted drug delivery systems based on biomaterials and nanomaterials is one of the most feasible strategies. Therefore, this review focused on the studies of targeted drug delivery systems combined with NCTD in recent years, including passive and active targeted drug delivery systems, and physicochemical targeted drug delivery systems for improving drug bioavailability and enhancing its efficacy, as well as increasing drug targeting ability and reducing its adverse effects.

Graphical Abstract

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.

Effect of norcantharidin on the proliferation, apoptosis, and cell cycle of human mesangial cells

AIMS

Norcantharidin (NCTD) regulates immune system function and reduces proteinuria. We sought to investigate the effect of NCTD on proliferation, apoptosis and cell cycle of cultured human mesangial cells (HMC) in vitro.

METHODS

HMC cells were divided into a normal control group, and various concentrations of NCTD group (2.5, 5, 10, 20, or 40 μg/mL). Cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, apoptosis was detected by Annexin V/propidium iodide (PI) assays, and morphological analysis was performed by Hoechest 33258 staining. Finally, cell cycle was analyzed by flow cytometry.

RESULTS

NCTD dose and time dependently inhibits HMC proliferation significantly (p < .05). Apoptosis dose and time dependently increased after NCTD treatment. Cell-cycle analysis revealed that the number of cells in the G2 phase increased significantly, whereas the fraction of cells in the S phase decreased, especially 24 h after 5 μg/ml NCTD treatment.

CONCLUSION

NCTD inhibits HMC cell proliferation, induces apoptosis, and affects the cell cycle.

One-step assembly of polymeric demethylcantharate prodrug/Akt1 shRNA complexes for enhanced cancer therapy

This report demonstrated a one-step assembly for co-delivering chemotherapeutics and therapeutic nucleic acids, constructed by integrating drug molecules into a nucleic acid condensing polymeric prodrug through degradable linkages. Demethylcantharate was selected as the model drug and pre-modified by esterifying its two carboxylic groups with 2-hydroxyethyl acrylate. The synthesized demethylcantharate diacrylate was then used to polymerize with linear polyethyleneimine (PEI 423) through a one-step Michael-addition reaction. The obtained cationic polymeric demethylcantharate prodrug was used to pack Akt1 shRNA into complexes through a one-step assembly. The formed complexes could release the parent drug demethylcantharate and Akt1 shRNA through the hydrolysis of ester bonds. Cellular assays involving cell uptake, cytotoxicity, and cell migration indicated that demethylcantharate and Akt1 shRNA co-delivered in the present form significantly and synergistically suppress the growth and metastasis of three human cancer cells. This work suggests that incorporating drug molecules into a nucleic acid-packing cationic polymer as a polymeric prodrug in a degradable form is a highly convenient and efficient way to co-deliver drugs and nucleic acids for cancer therapy.

Folate receptor-targeted liposomes loaded with a diacid metabolite of norcantharidin enhance antitumor potency for H22 hepatocellular carcinoma both in vitro and in vivo

The diacid metabolite of norcantharidin (DM-NCTD) is clinically effective against hepatocellular carcinoma (HCC), but is limited by its short half-life and high incidence of adverse effects at high doses. We developed a DM-NCTD-loaded, folic acid (FA)-modified, polyethylene glycolated (DM-NCTD/FA-PEG) liposome system to enhance the targeting effect and antitumor potency for HCC at a moderate dose based on our previous study. The DM-NCTD/FA-PEG liposome system produced liposomes with regular spherical morphology, with mean particle size approximately 200 nm, and an encapsulation efficiency >80%. MTT cytotoxicity assays demonstrated that the DM-NCTD/FA-PEG liposomes showed significantly stronger cytotoxicity effects on the H22 hepatoma cell line than did PEG liposomes without the FA modification (P<0.01). We used liquid chromatography–mass spectrometry for determination of DM-NCTD in tissues and tumors, and found it to be sensitive, rapid, and reliable. In addition, the biodistribution study showed that DM-NCTD liposomes improved tumor-targeting efficiency, and DM-NCTD/FA-PEG liposomes exhibited the highest efficiency of the treatments (P<0.01). Meanwhile, the results indicated that although the active liposome group had an apparently increased tumor-targeting efficiency of DM-NCTD, the risk to the kidney was higher than in the normal liposome group. With regard to in vivo antitumor activity, DM-NCTD/FA-PEG liposomes inhibited tumors in H22 tumor-bearing mice better than either free DM-NCTD or DM-NCTD/PEG liposomes (P<0.01), and induced considerably more significant cellular apoptosis in the tumors, with no obvious toxicity to the tissues of model mice or the liver tissue of normal mice, as shown by histopathological examination. All these results demonstrate that DM-NCTD-loaded FA-modified liposomes might have potential application for HCC-targeting therapy.