Efficacy of intra-arterial norcantharidin in suppressing tumour 14C-labelled glucose oxidative metabolism in rat Morris hepatoma

Insight into norcantharidin, a small-molecule synthetic compound with potential multi-target anticancer activities

Norcantharidin (NCTD) is a demethylated derivative of cantharidin, which is an anticancer active ingredient of traditional Chinese medicine, and is currently used clinically as a routine anti-cancer drug in China. Clarifying the anticancer effect and molecular mechanism of NCTD is critical for its clinical application. Here, we summarized the physiological, chemical, pharmacokinetic characteristics and clinical applications of NCTD. Besides, we mainly focus on its potential multi-target anticancer activities and underlying mechanisms, and discuss the problems existing in clinical application and scientific research of NCTD, so as to provide a potential anticancer therapeutic agent for human malignant tumors.

Intraarterial administration of norcantharidin attenuates ischemic stroke damage in rodents when given at the time of reperfusion: novel uses of endovascular capabilities

OBJECT Matrix metalloprotease-9 (MMP-9) plays a critical role in infarct progression, blood-brain barrier (BBB) disruption, and vasogenic edema. While systemic administration of MMP-9 inhibitors has shown neuroprotective promise in ischemic stroke, there has been little effort to incorporate these drugs into endovascular modalities. By modifying the rodent middle cerebral artery occlusion (MCAO) model to allow local intraarterial delivery of drugs, one has the ability to mimic endovascular delivery of therapeutics. Using this model, the authors sought to maximize the protective potential of MMP-9 inhibition by intraarterial administration of an MMP-9 inhibitor, norcantharidin (NCTD). METHODS Spontaneously hypertensive rats were subjected to 90-minute MCAO followed immediately by local intraarterial administration of NCTD. The rats' neurobehavioral performances were scored according to the ladder rung walking test results and the Garcia neurological test for as long as 7 days after stroke. MRI was also conducted 24 hours after the stroke to assess infarct volume and BBB disruption. At the end of the experimental protocol, rat brains were used for active MMP-9 immunohistochemical analysis to assess the degree of MMP-9 inhibition. RESULTS NCTD-treated rats showed significantly better neurobehavioral scores for all days tested. MR images also depicted significantly decreased infarct volumes and BBB disruption 24 hours after stroke. Inhibition of MMP-9 expression in the ischemic region was depicted on immunohistochemical analysis, wherein treated rats showed decreased active MMP-9 staining compared with controls. CONCLUSIONS Intraarterial NCTD significantly improved outcome when administered at the time of reperfusion in a spontaneously hypertensive rat stroke model. This study suggests that supplementing endovascular revascularization with local neuroprotective drug therapy may be a viable therapeutic strategy.

Norcantharidin inhibits pre-replicative complexes assembly of HepG2 cells

Norcantharidin (NCTD) is currently used for anticancer therapy but the exact mechanism of action remains unknown. Pre-replicative complexes (pre-RCs) are essential for cell DNA replication and highly related to malignant proliferation. Here, we examined the inhibitory effect of NCTD on pre-RC components in HepG2 cells. We showed that NCTD induced degradation of Cdc6 and Mcm2 in a dose-dependent manner. Under 100 μM NCTD concentration, about 70% of Cdc6 and 50% of Mcm2 were degraded. In addition, the nuclear translocation of Mcm6 was inhibited by NCTD. Further studies aiming at G1 synchronous cells showed that, NCTD reduced the chromatin-bound Cdc6, Mcm2 and Mcm6. Moreover, the cells were blocked from entering the S phase and accumulated at the G1 phase when released synchronously into the cell cycle. Consistently, the DNA replication was inhibited by NCTD. Finally, the combination NCTD with Cdc6 depletion lead to more severe cytotoxicity (88%) than NCTD (52%) and Cdc6 depletion (39%) alone. A synergic cytotoxicity was observed between Cdc6 depletion and NCTD. In conclusion, our results demonstrate that NCTD inhibits pre-RC assembly; subsequently blocks the G1 to S transition; and inhibits DNA replication in HepG2 cells. Pre-RCs are an intriguing target for cancer therapy, which merits further investigations for anticancer development.

Clinical report on transarterial neoadjuvant chemotherapy of malignant fibrous histiocytoma in soft tissue

PURPOSE

To review the experience in transarterial neoadjuvant chemotherapy of malignant fibrous histiocytoma (MFH) in soft tissue and to analyze the factors related to prognosis of MFH in soft tissue.

METHODS

Between September 1999 and December 2011, 101 cases of MFH in soft tissue patients treated by transarterial administration of Cisplatin, Adriamycin and Norcantharidin were divided into primary group and recurrent group, and the clinical documents were reviewed. Nine factors that might affect prognosis such as age, sex, tumor size, tumor site, tumor infiltration depth, recurrence if any, pathological type, histologic grade and histologic response of chemotherapy were analyzed statistically.

RESULTS

The 5-year relapse-free survival rate and the overall survival rate were 70.5 and 75.0 %, respectively, in the primary group; 56.1 and 57.9 %, respectively, in the recurrent group. Univariate analysis (log-rank test) showed that the factors affecting the prognosis were age (P = 0.03), tumor size (P = 0.01), pelvic tumor (P = 0.02), recurrence if any (P = 0.004), histologic grade (P = 0.01), and histologic response to chemotherapy (P = 0.007). Multivariate analysis showed that the major factors affecting prognosis were pelvic tumor (P = 0.01), tumor size (P = 0.002), histologic grade (P = 0.002), recurrence if any (P = 0.0004), and histologic response to chemotherapy (P = 0.008).

CONCLUSION

Transarterial neoadjuvant chemotherapy can significantly increase the curative efficacy of chemotherapy and survival rate in MFH treatment.

Norcantharidin modulates development of dendritic cells and prolongs skin allograft survival

BACKGROUND

To examine the effects of norcantharidin (NCTD) on development of human myeloid dendritic cells (DCs) in vitro and in skin allograft transplantation in vivo.

METHODS

Human CD14(+) monocytes were isolated and triggered differentiation and maturation toward myeloid DCs with and without NCTD. The cell morphology, viability, cell death, expression of surface markers and co-stimulatory molecules, allostimulatory activity, and cytokine production were examined for characterization of DCs. The rejection of mice skin allograft model was used to translate the in vitro effect of cantharidin (CTD) and NCTD on DCs.

RESULTS

DCs developed in the presence of NCTD showed decreased viability, cell death with necrosis, and lower expression of CD1a and CD83. DCs triggered in the presence of NCTD possessed a greater allostimulatory activity in naive CD4(+)CD45RA(+) T cells. NCTD modulated DCs through calcineurin phosphatase but not through mammalian target of rapamycin or downstream molecule p70S6 kinase. In vivo, NCTD caused accumulation and co-localization of antigen-presenting cells and regulatory T cells in the interfollicular area of the recipients' spleens. CTD and NCTD prolonged skin allograft survival along with less severe histopathological inflammatory reactions. CTD, but not NCTD, treatment caused elevation of serum alanine aminotransferase and evident mortality of the recipients.

CONCLUSION

NCTD modulated the differentiation and maturation of human myeloid DCs and caused deviation of standard DC differentiation toward a tolerogenic phenotype through calcineurin phosphatase inhibition. In vivo, both drugs effectively prolonged skin allograft survival. NCTD was less toxic than CTD, and thus, has potential for development as an immunosuppressant for transplant rejection.

Insect natural products and processes: new treatments for human disease

In this overview, some of the more significant recent developments in bioengineering natural products from insects with use or potential use in modern medicine are described, as well as in utilisation of insects as models for studying essential mammalian processes such as immune responses to pathogens. To date, insects have been relatively neglected as sources of modern drugs although they have provided valuable natural products, including honey and silk, for at least 4-7000 years, and have featured in folklore medicine for thousands of years. Particular examples of Insect Folk Medicines will briefly be described which have subsequently led through the application of molecular and bioengineering techniques to the development of bioactive compounds with great potential as pharmaceuticals in modern medicine. Insect products reviewed have been derived from honey, venom, silk, cantharidin, whole insect extracts, maggots, and blood-sucking arthropods. Drug activities detected include powerful antimicrobials against antibiotic-resistant bacteria and HIV, as well as anti-cancer, anti-angiogenesis and anti-coagulant factors and wound healing agents. Finally, the many problems in developing these insect products as human therapeutic drugs are considered and the possible solutions emerging to these problems are described.

Norcantharidin inhibits DNA replication and induces apoptosis with the cleavage of initiation protein Cdc6 in HL-60 cells

Norcantharidin (NCTD), a demethylated form of cantharidin, is currently used as an anti-cancer drug in China. However, the exact anti-cancer mechanism of NCTD on human cancer cells remains poorly understood. In the present study, NCTD inhibited proliferation and DNA replication effectively in HL-60 cells. DNA replication-initiation protein Cdc6 was cleaved after 12 h treatment with NCTD. This cleavage generated a truncated Cdc6 fragment with a relative molecular weight of 49 kDa and elongated treatment with NCTD resulted in a complete loss of Cdc6. In addition, we found that Cdc6 was present in both non-chromatin- and chromatin-bound fractions in the untreated HL-60 cells, and NCTD treatment led to the cleavage of Cdc6 in both fractions. NCTD-induced cleavage of Cdc6 was prevented by pre-treatment with caspase-3 inhibitor, suggesting the involvement of caspase-3 activity in the process. Furthermore, NCTD treatment resulted in apoptotic changes including granular nuclear morphology, DNA laddering and sub-G1 arrest in HL-60 cells. In conclusion, our study reveals that NCTD can inhibit DNA replication, and induce apoptosis and caspase-3-dependent cleavage of Cdc6. The anti-cancer effect of NCTD may be closely associated with the dysfunction of Cdc6 and our report is the first to put forward this point of view.

Effect of norcantharidin on proliferation and invasion of human gallbladder carcinoma GBC-SD cells

AIM: To investigate the effect of norcantharidin on proliferation and invasion of human gallbladder carcinoma GBC-SD cells in vitro and its anticancer mechanism.

METHODS: Human gallbladder carcinoma GBC-SD cells were cultured by cell culture technique. The growth and the invasiveness of GBC-SD cells in vitro were evaluated by the tetrazolium-based colorimetric assay and by the Matrigel experiment and the crossing-river test. Expression of PCNA, Ki-67, MMP₂ and TIMP₂ proteins of GBC-SD cells was determined by streptavidin–biotin complex method.

RESULTS: In vitro norcantharidin inhibited the growth and proliferation of GBC-SD cells in a dose- and time-dependent manner, with the IC₅₀ value of 56.18 μg/mL at 48 h. Norcantharidin began to inhibit the invasion of GBC-SD cells at the concentration of 5 μg/mL, and the invasive action of GBC-SD cells was inhibited completely and their crossing-river time was prolonged significantly at 40 μg/mL. After treatment with norcantharidin, the expression of PCNA, Ki-67, and MMP₂ was significantly decreased. With the increase in TIMP₂ expression, the MMP₂ to TIMP₂ ratio was decreased significantly (P<0.05).

CONCLUSION: Norcantharidin inhibits the proliferation and growth of human gallbladder carcinoma cells in vitro at relatively low concentrations by inhibiting PCNA and Ki-67 expression. Its anti-invasive activity may be the result of decrease in MMP₂ to TIMP₂ ratio and reduced cell motility.

Effector mechanisms of norcantharidin-induced mitotic arrest and apoptosis in human hepatoma cells

NCTD is a demethylated form of cantharidin with antitumor properties, which is now in use as a routine anticancer drug against hepatoma. However, there is limited information on the effect of NCTD on human cancer cells. In the present study, NCTD inhibited proliferation, caused mitotic arrest, then progressed to apoptosis within 96 hr in 3 human hepatoma cell lines: HepG2, Hep3B and Huh-7. NCTD treatment (5 microg/ml) enhanced the expression of Cdc25C and p21(Cip1/Waf1), increasing the phosphorylation of these 2 proteins. In addition, NCTD treatment induced an earlier increase in cyclin B1-associated histone H1 kinase activity within 48 hr, but an approximately 70% reduction of both protein level and kinase activity of cyclin B1 was observed at 72 hr. Treatment with NCTD significantly decreased the expression of p53 protein but did not affect the expression of Cdk1 and p27(Kip1). Moreover, NCTD treatment also increased the phosphorylation of Bcl-2 and Bcl-X(L) but did not affect the expression of Bax or Bad. Bcl-2 phosphorylation appears to inhibit its binding to Bax since less Bax was detected in immunocomplex with Bcl-2 in NCTD-treated HepG2 cells. In addition, NCTD treatment caused activation of caspase-9 and caspase-3, preceding DNA fragmentation and morphologic features of apoptosis. Pretreatment with the broad-spectrum caspase inhibitor z-VAD-fmk markedly inhibited NCTD-induced caspase-3 activity and cell death. These results suggest that phosphorylation of p21(Cip1/Waf1) and Cdc25C and biphasic regulation of cyclin B1-associated kinase activity may contribute to NCTD-induced M-phase cell-cycle arrest. Furthermore, the increase of p21(Cip1/Waf1), phosphorylation of Bcl-2 and Bcl-X(L), activation of caspase-9 and caspase-3 may be the molecular mechanism through which NCTD induces apoptosis.

Cytotoxicity and L-amino acid oxidase activity of crude insect drugs

The cytotoxicity of crude insect drugs was measured using HeLa cells originating from human cervix and uterine cancer, using the dye uptake assay in order to find potential anticancer agents. Three kinds of extracts (buffer, methanol and ethylacetate) were prepared from 26 insects and used as raw materials for the activity assay. Among these, the buffer extracts from Tabanus, Mylabris and Huechys showed a potent anticancer activity, and those from Catharsius, Red ant, Scorpion, Tabanus and Vespae Nidus showed a strong L-amino acid oxidase (AAO) activity as well as cytotoxicity. In contrast, buffer extracts from Gryllotalpa orientalis and Apriona germari larvae showed greater/more rapid Hela cell growth than that of other insects.