Cantharidin

Anticancer Res. 2015 Feb;35(2):795-804.

Cantharidin induces DNA damage and inhibits DNA repair-associated protein expressions in TSGH8301 human bladder cancer cell.[Pubmed: 25667459]

Cantharidin is an active component of mylabris, which has been used as a traditional Chinese medicine. Cantharidin has been shown to have antitumor activity against several types of human cancers in vitro and in animal models in vivo.
METHODS AND RESULTS:
We investigated whether Cantharidin induces DNA damage and affects DNA damage repair-associated protein levels in TSGH8301 human bladder cancer cells. Using flow cytometry to measure viable cells, Cantharidin was found to reduce the number of viable cells in a dose-dependent manner. Comet assay, 4',6-diamidino-2-phenylindole (DAPI) staining and DNA gel electrophoresis were used to measure DNA damage and condensation; the results indicated that Cantharidin induced DNA damage (comet tail), DNA condensation (white DAPI staining) and DNA damage (DNA smear). Results from western blotting showed that Cantharidin inhibited the expression of DNA-dependent serine/threonine protein kinase, poly-ADP ribose polymerase, phosphate-ataxia-telangiectasia and RAD3-related, O-6-methylguanine-DNA methyltransferase, breast cancer susceptibility protein 1, mediator of DNA damage checkpoint protein 1, phospho-histone H2A.X, but increased that of phosphorylated p53 following 6 and 24 h treatment. Confocal laser microscopy was used to examine the protein translocation; Cantharidin suppressed the levels of p-H2A.X and MDC1 but increased the levels of p-p53 in TSGH8301 cells.
CONCLUSIONS:
In conclusion, we found that Cantharidin-induced cell death may occur through the induction of DNA damage and suppression of DNA repair-associated protein expression in TSGH8301 cells.

Cancer Lett. 2008 Dec 8;272(1):102-9.

Cantharidin reverses multidrug resistance of human hepatoma HepG2/ADM cells via down-regulation of P-glycoprotein expression.[Pubmed: 18703276 ]

Multidrug resistance (MDR) is a serious obstacle encountered in cancer treatment.
METHODS AND RESULTS:
In this study, we established an in vitro multiple drug resistant HepG2 cell line (HepG2/ADM), and characterized its MDR. This model was used to screen potential candidate chemosensitisers from over 200 purified naturally occurring compounds extracted from plants and animals. Cantharidin was found to have a significant reversal on MDR in our model. Further, our results showed that Cantharidin could significantly inhibit P-gp (P-glycoprotein) expression, mRNA transcription, as well as MDR1 promoter activity.
CONCLUSIONS:
These results suggest that Cantharidin is a novel and potent MDR reversal agent and may be a potential adjunctive agent for tumor chemotherapy.

FEBS Lett. 1993 Sep 20;330(3):283-6.

Cantharidin, another natural toxin that inhibits the activity of serine/threonine protein phosphatases types 1 and 2A.[Pubmed: 8397101]

Cantharidin, a natural toxicant of blister beetles, is a strong inhibitor of protein phosphatases types 1 (PP1) and 2A (PP2A).
METHODS AND RESULTS:
Like okadaic acid, Cantharidin inhibits the activity of the purified catalytic subunit of PP2A (IC50 = 0.16 microM) at a lower concentration than that of PP1 (IC50 = 1.7 microM) and only inhibits the activity of protein phosphatase type 2B (PP2B) at high concentrations. Dose-inhibition studies conducted with whole cell homogenates indicate that Cantharidin also inhibits the native forms of these enzymes.
CONCLUSIONS:
Thus, Cantharidin, which is economical and readily available, may be useful as an additional probe for studying the functions of serine/threonine protein phosphatases.

Mol Med Rep. 2015 Jul;12(1):1030-42.

cDNA microarray analysis of the effect of cantharidin on DNA damage, cell cycle and apoptosis-associated gene expression in NCI-H460 human lung cancer cells in vitro.[Pubmed: 25815777]

Cantharidin (CTD) induces cytotoxic effects in different types of human cancer cell; however, to date, there have been no studies on the effects of CTD on gene expression in human lung cancer cells and the potential associated signaling pathways.
METHODS AND RESULTS:
Therefore, the present study aimed to investigate how CTD affects the expression of key genes and functional pathways of human H460 lung cancer cells using complementary DNA microarray analysis. Human H460 lung cancer cells were cultured for 24 h in the presence or absence of 10 μM CTD; gene expression was then examined using microarray analysis. The results indicated that 8 genes were upregulated > 4-fold, 29 genes were upregulated >3-4-fold and 156 genes were upregulated >2-3-fold. In addition, 1 gene was downregulated >4 fold, 14 genes were downregulated >3-4-fold and 150 genes were downregulated >2-3 fold in H460 cells following exposure to CTD. It was found that CTD affected DNA damage genes, including DNIT3 and GADD45A, which were upregulated 2.26- and 2.60-fold, respectively, as well as DdiT4, which was downregulated 3.14-fold. In addition, the expression of genes associated with the cell cycle progression were altered, including CCND2, CDKL3 and RASA4, which were upregulated 2.72-, 2.19- and 2.72-fold, respectively; however, CDC42EP3 was downregulated 2.16-fold. Furthermore, apoptosis-associated genes were differentially expressed, including CARD6, which was upregulated 3.54-fold.
CONCLUSIONS:
In conclusion, the present study demonstrated that CTD affected the expression of genes associated with DNA damage, cell cycle progression and apoptotic cell death in human lung cancer H460 cells.

Anticancer Res. 2015 Feb;35(2):729-38.

Cantharidin impairs cell migration and invasion of A375.S2 human melanoma cells by suppressing MMP-2 and -9 through PI3K/NF-κB signaling pathways.[Pubmed: 25667452]

Cancer metastasis is the major cause of cancer patient death. Melanoma is a highly important metastasis in human cancer. Cantharidin (CTD), identified as an active component of natural mylabris (Mylabris phalerata Pallas), induces apoptosis in many human cancer cells.
METHODS AND RESULTS:
In the present study, we investigated the anti-metastasis effects of CTD in human melanoma cancer A375.S2 cells. Flow cytometry was used to measure CTD-induced cytotoxic effects in A375.S2 cells. Wound healing assay indicated that CTD suppressed the migration of A375.S2 cells in a dose-dependent manner. The Matrigel Transwell Assay was used for cell migration and invasion examination and the results showed that CTD inhibited both. Gelatin zymography was used to investigate the activities of MMP-2/9 and the results indicated that CTD inhibited the enzymatic activities of MMP-2/9 in A375.S2 cells. The protein expression of A375.S2 cells following incubation with CTD was examined by western blotting and the results showed that CTD decreased the expression of ERK1/2, PI3K, FAK, MMP-2, -9, COX-2, NF-κB p65, TIMP 1, TIMP 2, VEFG, uPA, Rho A, GRB2, ROCK-1 and Ras, but increased the expressions of p38, JNK, p-c-jun and PKC.
CONCLUSIONS:
Based on those observations, we suggest that CTD may be used as a novel anti-cancer metastasis agent of human melanoma cancer in the future.