Design and Synthesis of Disodium Phosphate Derivatives of Norcantharidin

Aim To design and synthesize norcantharidin disodium phosphate derivatives. Methotis Diels-Alder reaction between furan and maleic anhydride afforded dehydronorcantharidin, and subsequent hydrogenation, phosphorylation, and basification gave compounds 1 and 2, separately. Resuits The structures of compounds were confirmed by IR, NMR and FAB-MS. The aqueous solubility of 1 and 2 were improved, compared with the parent compounds, and their activities were more potent than norcantharidin 4 against MGCS03 cell lines. Conclusion The phosphorylation of norcantharidin analogues is an effective way to increase the activity and solubility.

Apoptosis induced by norcantharidin in human tumor cells

INTRODUCTIONThe antitumor activity of norcantharidin (NCTD),the demethylated analogue of cantharidin,wasstudied in the early 1980s in China.NCTD has noside effects on urinary organs which cantharidin hasshown and is easier to synthesize,and it can inhibitthe proliferation of several tumor cell lines as wellas transplanted tumors.Clinical trials with NCTD asa monotherapeutic agent indicated that NCTD hadbeneficial effects in patients with different kinds

Inhibitory effect of norcantharidin on the growth of human gallbladder carcinoma GBC-SD cells in vitro

BACKGROUND: Gallbladder carcinoma is a lethal malignant neoplasm with dismal surgical results. Unfortunately, the adjuvant therapies for gallbladder carcinoma such as chemotherapy and radiotherapy are also disappointing. We reported that norcantharidin (NCTD), a demethylated form of cantharidin, which is an active ingredient of the Chinese medicine Mylabris, was used against human gallbladder carcinoma GBC-SD cells. In the present study, we further studied the mechanism underlying the inhibitory effect of NCTD on growth of human gallbladder carcinoma GBC-SD cells in vitro. METHODS: Human gallbladder carcinoma GBC-SD cells were grown in cell culture and divided into a NCTD group and a control group. The inhibitory effect of NCTD on growth of GBC-SD cells was investigated by evaluation of proliferation, cell cycle, apoptosis and morphological changes of the cells. Cell proliferation was assessed by tetrazolium-based colorimetric assay. The induction of cell cycle arrest and apoptosis was measured by flow cytometry. The morphological changes of the cells were observed by light- and electron-microscopy. To elucidate the anticancer mechanism of NCTD, expression of the proliferation-related gene proteins PCNA, Ki-67, cyclin-D-1 and p27 and the apoptosis-related gene proteins Bcl-2, Bax and Survivin were determined by the streptavidin-biotin complex method and RT-PCR. RESULTS: NCTD inhibited the proliferation of GBCSD cells in a dose- and time-dependent manner, with an IC50 of 56.18 mu g/ml at 48 hours. The flow cytometric profiles revealed that NCTD (at the IC50 for 48 hours) significantly increased the proportion of cells in G(2)/M phase and significantly decreased the proportion of cells in S phase, with a significantly increased rate of cell apoptosis. After treatment with the 48-hour IC50 dose of NCTD, cell shrinkage, vacuolar cytoplasm, membrane budding, karyorrhexis, karyolysis, chromosome condensation and chromatin aggregation in some GBCSD cells were observed by light-microscopy; decreased microvilli, Golgiosome atrophy, mitochondrial swelling, nuclear shrinkage, chromosome condensation and typical apoptosis bodies were seen by electron-microscopy, and the morphological changes of apoptosis occurred in GBCSD cells. The expression of PCNA, Ki-67 and Bcl-2 proteins decreased significantly; the Pix or relative levels of PCNA mRNA, cyclin-D-1 mRNA, Bcl-2 mRNA and Survivin mRNA decreased significantly, whereas the Pix or relative levels of p27 mRNA and Bax mRNA increased significantly. CONCLUSIONS: NCTD inhibits the growth of human gallbladder carcinoma GBC-SD cells in vitro. Its anticancer mechanism may correlate with inhibition of cell proliferation, arrest of the cell cycle, blockage of DNA synthesis, influence on cell metabolism, induction of cell apoptosis and influence on expression of the proliferation-related genes PCNA, Ki-67, cyclin-D-1 and p27, and the apoptosis-related genes Bcl-2, Bax and Survivin in human gallbladder carcinoma GBC-SD cells.

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 μ/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.

Norcantharidin inhibits growth of human gallbladder carcinoma xenografted tumors in nude mice by inducing apoptosis and blocking the cell cycle in vivo

BACKGROUND: Gallbladder carcinoma, a lethal malignant neoplasm with poor prognosis, has dismal results of surgical resection and chemoradiotherapy. We previously reported that norcantharidin (NCTD) is useful against growth, proliferation, and invasion of human gallbladder carcinoma GBC-SD cells in vitro. In this study, we further studied the inhibitory effect of NCTD on the growth of xenografted tumors of human gallbladder carcinoma in nude mice in vivo and the underlying mechanisms. METHODS: The tumor xenograft model of human gallbladder carcinoma in nude mice in vivo was established with subcutaneous GBC-SD cells. The experimental mice were randomly divided into control, 5-FU, NCTD, and NCTD+5-FU groups which were given different treatments. Tumor growth in terms of size, growth curve, and inhibitory rate was evaluated. Cell cycle, apoptosis, and morphological changes of the xenografted tumors were assessed by flow cytometry and light/electron microscopy. The expression of the cell cycle-related proteins cyclin-D1 and p27 as well as the apoptosis-related proteins Bcl-2, Box, and survivin were determined by the streptavidin-biotin complex (SABC) method and RT-PCR. RESULTS: NCTD inhibited the growth of the xenografted tumors in a dose- and time-dependent manner. Tumor volume decreased (5.61+/-0.39 vs. 9.78+/-0.61 cm(3), P=0.000) with an increased tumor inhibitory rate (42.63% vs. 0%, P=0.012) in the NTCD group compared with the control group. The apoptosis rate increased (15.08+/-1.49% vs. 5.49+/-0.59%, P=0.0001) along with a decreased percentage of cells in S phase (43.47+/-2.83% vs. 69.85+/-1.96%, P=0.0001) in the NTCD group compared with the control group. The morphological changes of apoptosis such as nuclear shrinkage, chromatin aggregation, chromosome condensation, and typical apoptosis bodies in the xenografted tumor cells induced by NCTD were observed by light and electron microscopy. The expression of cyclin-D1, Bcl-2 and survivin proteins/mRNAs decreased significantly, with increased expression of p27 and Bax proteins/mRNAs in the NCTD group compared with the control group. CONCLUSION: NCTD inhibits the growth of xenografted tumors of human gallbladder carcinoma in nude mice by inducing apoptosis and blocking the cell cycle in vivo.

Improved synthesis and characterization of L-histidine norcantharimide,a novel potent protein phosphatase 2A inhibitor

Improved synthesis and structure identification of L-histidine norcantharimide , a potent PP2A inhibitor was reported. Condensation between norcantharidin and L-histidine in 95% EtOH at reflux temperature affords L-histidine norcantharimide in 97.0f% yield which is much higher compared with literature, and more importantly, the configuration is retained. The chemical structure of the compound was re-elucidated through IR, FAB-MS, ^1H NMR, ^13C NMR and 2D NMR （^1H, ^13C-COSY and HMBC）, the fundamental physical data, including optical data being also firstly reported. Preliminary cytotoxicity evaluation showed that the target compound was probably more potent than norcantharidin against a panel of human cancer cell lines. Design and synthesis of amino acid （nor） cantharirnides would provide a convenient and rational structure modification of （nor） cantharidin and open new avenues to explore new promising candidates.

Norcantharidin combined with ABT-737 for hepatocellular carcinoma: Therapeutic effects and molecular mechanisms

AIM: To study the therapeutic effect of norcantharidin(NCTD) combined with ABT-737 on hepatocellular carcinoma cells and the molecular mechanism. METHODS: Two hepatocellular carcinoma(HCC) cell lines, Hep G2 and SMMC-7721, were selected. ABT-737 and NCTD were allocated into groups to be used alone or in combination. Hep G2 and SMMC-7721 cells were cultured in vitro. Liver cancer cells in the logarithmic phase of growth were vaccinated and cultured to the cell wall stage; these cells were treated for 48 h with different concentrations of NCTD, or ABT-737, or NCTD combined with ABT-737. The cell proliferation inhibition rate was detected by methyl thiazolyl tetrazolium. The expression of Mcl in HCC cells was detected by Western Blotting, and the cells in each group after treatment had apoptosis detected by flow cytometry. The proliferation inhibition rate, the expression of Mcl-1 in cells and the apoptosis inducing effect of treatment were observed in each group, and the effect of NCTD on ABT-737 in the treatment of HCC and its mechanism of action were analyzed.RESULTS: As the concentration of NCTD increased, the cell proliferation inhibition rate gradually decreased; and the treatment effect of ABT-737 1-3 μm combined with NCTD on cell proliferation inhibition was stronger than that of ABT-737 alone. The difference was statistically significant(P < 0.05). In observing the expression of Mcl-1 in cells after the treatment of different concentrations of NCTD, this was partiallyinhibited after treatment with NCTD 15 μm, and the expression of Mcl-1 was almost undetectable after treatment with NCTD 30 μm and 60 μm. The effect on inducing apoptosis with the treatment of ABT-737 or NCTD alone for 48 h was lower than that of the control group. The difference was not statistically significant(P > 0.05). The effect on inducing apoptosis in Hep G2 and SMMC-7721 cells with the treatment of ABT-737 combined with NCTD for 48 h was greater than that of ABT-737 or NCTD alone. The difference was statistically significant(P < 0.05). CONCLUSION: NCTD combined with ABT-737 has a positive role in the treatment of HCC, and it has great value in clinical research.

Influence of norcantharidin on proliferation,proliferation-related gene proteins prolifera-ting cell nuclear antigen and Ki-67 of human gallbladder carcinoma GBC-SD cells

BACKGROUND: Gallbladder carcinoma is a highly lethal and aggressive disease with early metastasis, strong invasion and poor prognosis. Most patients with this disease are at the advanced and un-resectable stage and should be consi- dered for palliative treatment such as chemotherapy and ra- diotherapy. Unfortunately, reports of chemotherapy and radiotherapy for gallbladder carcinoma are disappointing. We investigated the influence of norcantharidin (NCTD) on proliferation, proliferation-related gene proteins PCNA and Ki-67 of human gallbladder carcinoma GBC-SD cells in vitro. METHODS: GBC-SD cell lines of human gallbladder carci- noma were cultured by the cell culture technique. The ex- periment was divided into NCTD group and control group. The tetrazolium-based colorimetric assay was used to evaluate cell growth. The streptavidin-biotin complex method was used to determine the expressions of prolifera- tion-related gene proteins PCNA and Ki-67 of human gall- bladder carcinoma GBC-SD cells. RESULTS: NCTD inhibited the growth and proliferation of GBC-SD cells from 10 mg/L or after 6 hours in a dose- and time-dependent manner, with the IC50 value of 56.18 μg/ ml at 48 hours. After treatment with NCTD, the expression of PCNA (0.932 ±0.031 vs. 0.318 ±0.023, P<0.001) and Ki-67 (0.964 ±0.092 vs. 0.297 ±0.018, P<0.001) proteins were decreased significantly. CONCLUSION: NCTD inhibits the proliferation of human gallbladder carcinoma GBC-SD cells in vitro and the expres- sion of their proliferation-related gene proteins PCNA and Ki-67.

2D-QSAR Studies on the Norcantharidin Analogues as Protein Phosphatase 1 and 2A Inhibitors

The Two-dimensional Quantitative Structure-activity Relationship （2D-QSAR） of a series of novel norcantharidin analogues, which exhibit hnhibitory activities of protein phosphatase 1 and 2A （PP1 and PP2A）, has been studied with a combined method of ab initio （I/F）, molecular mechanics （MM＋） and statistics. The established 2D-QSAR model （Eq. 1） for PP1 shows a reasonable regressive performance （R2= 0.749）, and the hydrophobic property of this molecule plays a decisive role in determining the inhibitory activity of PP1. In addition, the established 2D-QSAR model （Eq. 2） for PP2A also shows an acceptable regressive performance （R2= 0.701）, and the dipole moment of the molecule determines the inhibitory activity of PP2A.

Metal-organic framework IRMOFs coated with a temperaturesensitive gel delivering norcantharidin to treat liver cancer

BACKGROUND Norcantharidin(NCTD)is suitable for the treatment of primary liver cancer,especially early and middle primary liver cancer.This compound can reduce tumors and improve immune function.However,the side effects of NCTD have limited its application.There is a marked need to reduce the side effects and increase the efficacy of NCTD.AIM To develop a nanomaterial carrier,NCTD-loaded metal-organic framework IRMOF-3 coated with a temperature-sensitive gel(NCTD-IRMOF-3-Gel),aiming to improve the anticancer activity of NCTD and reduce the drug dose.METHODS NCTD-IRMOF-3-Gel was obtained by a coordination reaction.The apparent characteristics and in vitro release of NCTD-IRMOF-3-Gel were investigated.Cell cytotoxicity assays,flow cytometry,and apoptosis experiments in mouse hepatoma(Hepa1-6)cells were used to determine the anti-liver cancer activity of NCTD-IRMOF-3-Gel in in vitro models.RESULTS The particle size of NCTD-IRMOF-3-Gel was 50-100 nm,and the particle size distribution was uniform.The release curve showed that NCTD-IRMOF-3-Gel had an obvious sustained-release effect.The cytotoxicity assays showed that the free drug NCTD and NCTD-IRMOF-3-Gel treatments markedly inhibited Hepa1-6 cell proliferation,and the inhibition rate increased with increasing drug concentration.By flow cytometry,NCTD-IRMOF-3-Gel was observed to block the Hepa1-6 cell cycle in the S and G2/M phases,and the thermosensitive gel nanoparticles may inhibit cell proliferation by inducing cell cycle arrest.Apoptosis experiments showed that NCTD-IRMOF-3-Gel induced the apoptosis of Hepa1-6 cells.CONCLUSION Our results indicated that the NCTD-IRMOF-3-Gel may be beneficial for liver cancer disease treatment.

Preparation and Evaluation of Norcantharidin-encapsulated Liposomes Modified with a Novel CD19 Monoclonal Antibody 2E8

In this study, norcanthridin （NCTD）-encapsulated liposomes were modified with a novel murine anti-human CD19 monoclonal antibody 2E8 （2E8-NCTD-liposomes） and the targeting efficiency and specific cytotoxicity of 2E8-NCTD-liposomes to CD19^＋ leukemia cells were evaluated. BALB/c mice were injected with 2E8 hybridoma cells to obtain 2E8 monoclonal antibody （mAb）. NCTD-liposomes were prepared by using film dispersion method. 2E8 mAbs were linked to NCTD-liposomes using post-incorporation technology. Flow cytometry showed that the targeting efficiency of purified 2E8 mAbs on CD19＋ Nalm-6 cells was 99.93%. The purified 2E8 mAbs were conjugated with NCTD-liposomes to prepare 2E8-NCTD-liposomes whose targeting efficiency on CD19^＋ Nalm-6 was also 95.82%. The average size of 2E8-NCTD-liposomes was 118.32 nm in diameter. HPLC showed that the encapsulation efficiency of NCTD was 46.51%. When the molar ratio of 2E8/Mal-PEG2000-DSPE reached 1：50, we obtained the liposomes with 9 2E8 molecules per liposome. The targeting efficiency of 2E8-NCTD-liposomes on CD19^＋ leukemia cells was significantly higher than that on CD19-1eukemia cells. Similarly, the targeting efficiency of the immtmoliposomes was also higher than that of the NCTDAiposomes on CD 19^＋ leukemia cells. Those results were consistent with those observed by laser scanning confocal microscopy. 3-（4, 5-Dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay demonstrated that 2E8-NCTD-liposomes specifically killed Nalm-6 cells in a dose- and time-dependent manner. The viability of Nalm-6 cells treated by 2E8-NCTD-liposomes was significantly lower than that of Molt-3 cells and it was also significantly lower than that of Nahn-6 cells treated with the same concentration of NCTD-liposomes or free NCTD. We are led to concluded that 2E8 antigen can serve as a specific targeting molecule of B lineage hematopoietic malignancies for liposome targeting, and 2E8-NCTD-liposomes can be used as a new and effective means for the treatment of B lineage hematopoietic malignancies.

Mitogen-activated protein kinase-dependent apoptosis in norcan-tharidin-treated A375-S2 cells is proceeded by the activation of protein kinase C

We have reported that norcantharidin (NCTD) induces human melanoma A375-S2cell apoptosis and that the activation of caspase and the mitochondrial pathway are involved in theapoptotic process. This study aimed at investigating the roles of mitogen-activated protein kinase(MAPK) and protein kinase C (PKC) in A375-S2 cell apoptosis induced by NCTD. We assessed theeffects of NCTD on cell growth inhibition using the 3-(4,5-dimethylthiazol-2-yl)-2 ,5-dipheyltetrazolium bromide ( MTT) assay, DNA fragmentation ( DNA agarose gel electrophoresis ) ,and MAPK protein levels (Western blot analysis) in A375-S2 cells. Photomicroscopic data were alsocollected. The NCTD inhibitory effect on A375-S2 cells was partially reversed by MAPK and PKCinhibitors. The expression of phosphorylated JNK and p38 also increased after the treatment withNCTD, and inhibitors of c-Jun NH2 - terminal kinase (JNK) and p38 ( SP600125 and SB203580,respectively) had significant inhibitory effects on the upregulation of phosphorylated JNK and p38expression. Simultaneously, the PKC inhibitor staurosporine blocked the upregulation ofphosphorylated JNK and phosphorylated p_(38), but had little effect on extracellularsignal-regulated kinase (ERK) expression. These results suggest that the activation of JNK andp_(38) MAPK promotes the process of NCTD-induced A375-S2 cell apoptosis and that PKC plays animportant regulation role in the activation of MAPKs.

Induction of Apoptosis in Human Hep3B Hepatoma Cells by Norcantharidin through a p53 Independent Pathway via TRAIL/DR5 Signal Transduction

Objective： To investigate the inhibitory activities of norcantharidin （NCTD）, a demethylated analogue of cantharidin, on Hep3B cells （a human hepatoma cell line） with deficiency of p53. Methods： The survival rate of the Hep3B cells after treating with NCTD was measured by MTT assay. Cell cycle of treated cells was analyzed by flow cytometry, and DNA fragmentation was observed by electrophoresis. The influence of inhibitors for various caspases and anti-death receptors antibodies on the NCTD-induced apoptosis in the cells was determined. Results： NCTD treatment resulted in growth inhibition of Hep3B cells in a dose- and time-dependent manner. Cell cycle analysis of the cells after treatment with NCTD for 48 h shows that NCTD induced G2M phase arrest occursat low concentration （≤25 μ mol/L） but G0G1 phase arrest at high concentration （50 μ mol/L）. The addition of both caspase-3 and caspase-10 inhibitors completely inhibited DNA fragmentation. Addition of anti-TRAIL/DR5 antibody significantly inhibited DNA fragmentation. Conclusion： NCTD may inhibit the proliferation of Hep3B cells by arresting cell cycle at G2M or G0G1 phase, and induce cells apoptosis via TRAIL/DR5 signal transduction through activation of caspase-3 and caspase-10 by a p53-independent pathway,

Protective Effect of Norcantharidin on Collagen-Induced Arthritis Rats

Objective： To observe the effect of norcantharidin（NCTD） on collagen-induced arthritis（CIA） rats. Methods： Sixty Sprague-Dawley（SD） rats were randomly divided into 6 groups（n=10）： normal group, CIA model group（model group）, NCTD low-dose group [1.35 mg/（kg·d）], NCTD middle-dose group [2.7 mg/（kg·d）], NCTD high-dose group [5.4 mg/（kg·d）] and methotrexate（MTX） group [1.8 mg/（kg/w）]. Anesthetized rats were sacrificed by luxation of cervical vertebra after 4 weeks of administration. The arthritis scores were evaluated twice a week. The pathological changes in the ankle joints of rats were observed by hematoxylin-eosin（H＆E） staining. The serum levels of interleukin（IL） 1β, IL-6, tumor necrosis factor（TNF）-α, vascular endothelial growth factor（VEGF）, IL-17 and transform growth factor（TGF） β were detected by enzyme linked immunosorbent assay（ELISA）. The mRNA expression of retinoid-related orphan nuclear receptor γ t（ROR γ t） and forkhead box P3（Foxp3） in peripheral blood lymphocytes were confirmed by real-time polymerase chain reaction. Results： MTX and high-dose NCTD not only decreased the arthritis scores but also alleviated the pathological changes in CIA rats＇ ankle joints compared with the model group（P〈0.05 or P〈0.01）. All doses of NCTD significantly inhibited the serum levels of IL-6, IL-17 and TNF-α in CIA rats（P〈0.05）. Only middle-and high-dose of NCTD prominently decreased serum IL-1β and TGF-β levels of CIA rats（P〈0.05）. However, NCTD has no effect on vascular endothelial growth factor（VEGF） level in CIA rats. The Foxp3 mRNA expression in all NCTD groups were increased significantly than in the model group（P〈0.05）. The mRNA expression of RORγt in NCTD high-dose group was decreased apparently in comparison with the model group（P〈0.05）. Conclusion： NCTD showed therapeutic effect on CIA rats by inhibition of cytokines and regulation of Th17/Treg cells.

Study on Norcantharidin-induced Apoptosis in SMMC-7721 Cells through Mitochondrial Pathways

Objective： To investigate the mechanism of norcantharidin （NCTD）-induced SMMC-7721 hepatoma cell apoptosis. Methods： SMMC-7721 cell growth inhibition was measured by the MTT method. Apoptosis was detected by Annexin Ⅴ/propidium iodide staining. The mitochondrial membrane potential was measured by flow cytometry. Western blot analysis was used to evaluate the level of cytochrome c, caspase-3, AIF, Bcl-2 and Bax expression. Results： NCTD inhibited SMMC-7721 cell growth in a time-and dose-dependent manner. The cells treated with NCTD showed the loss of mitochondrial membrane potential. The activities of caspase-3, cytochrome c, AIF, and Bax were up-regulated after NCTD treatment at different doses. The expression of Bcl-2 was decreased after treatment with NCTD. Conclusions： NCTD could induce SMMC-7721 cell apoptosis. The activation of the mitochondrial pathway was involved in the process of NCTD-induced SMMC-7721 cell apoptosis.

Synthesis, Antiproliferative Activity and DNA-Binding Properties of Nitrogen and Sulfur Heterocyclic Norcantharidin Acylamide Acid

Three novel norcantharidin acylamide acids （L1 =N-thiadiazole norcantharidin acylamide acid, CIoHIlN304S; L2=N-thiazole norcantharidin acylamide acid, CjIHI2N204S and L3=N-benzothiazole norcantharidin acylamide acid, C15H14N204S） were synthesized by the reactions of norcantharidin （NCTD=7-oxabicyclo[2,2,1 ]heptane-2,3- dicarboxylic acid anhydride, C8H8O4） with 2-amino-1,3,4-thiadiazole （C2H3N3S）, 2-aminothiazole （C3H4N2S） and 2-aminobenzothiazole （C7H6N2S）, respectively. Their structures were characterized by elemental analysis, IR, and NMR. The inhibition rates of L3 was much higher than those of Lj and L2 against human hepatoma cells SMMC7721 cell lines in vitro. The interaction between the compounds and DNA was studied by means of fluorescence quenching studies and viscosity measurements. The emission intensities decreased obviously with increasing concentration of the compounds in the fluorescence quenching experiments. The linear Stern-Volmer quenching constant Ksq values were 0.62 （Ll）, 0.55 （L2） and 1.08 （L3）, respectively. The binding abilities followed the trend from high to low were L3, L1 and L2, respectively. The results of viscosity measurements showed that L1 and L2 might bind to DNA via partial intercalation, while L3 bound mainly in intercalation.