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Gambogic acid (GA) was approved by the Chinese Food and Drug Administration for phase II clinical trials in patients with solid tumors. Recently, combinations of GA and chemotherapeutic agents have represented a promising therapeutic approach for cancer. However, little is known about the effect of GA on drug metabolism enzymes. In this study, we report for the first time that GA is a potent repressor of the cytochrome P450 3A4 (CYP3A4) enzyme, which is responsible for the oxidative metabolism of more than 60% of all pharmaceuticals. After HepG2 cells were treated with GA, the expression of CYP3A4 decreased at both the mRNA and protein levels, and CYP3A4 enzymatic activity was also reduced. Moreover, GA-mediated repression of CYP3A4 occurred after the decrease of PXR. Knockdown of PXR decreased CYP3A4 at the mRNA and protein levels, whereas PXR overexpression increased the CYP3A4 mRNA and protein levels. GA markedly decreased CYP3A4 expression in both normal and PXR overexpressing cells. Meanwhile, differentiated embryonic chondrocyte gene 1 (DEC1) expression rapidly increased in response to GA treatment, and subsequently, CYP3A4 expression continuously decreased. Overexpression of DEC1 decreased CYP3A4 mRNA and protein levels, and knockdown of DEC1 partially abolished the GA-mediated decrease in CYP3A4 expression. Taken together, our data suggest that two transcriptional factors, PXR and DEC1, are involved in the GA-mediated suppression of CYP3A4 in HepG2 cells.

To establish a novel method for preparing molecularly imprinted polymers for ginsenoside Rg1 with better character contrast to previous studies, we have prepared novel surface molecular imprinted polymers (S-MIPs) using ginsenoside Rg1 as the template molecule, Acrylamide (AM) as the functional monomer, and silica gel as the carrier. The morphology of S-MIPs was characterized by scanning electron microscope (SEM) and its static adsorption capacity was measured by the Scatchard equation.

The objective of this study was to investigate the apoptosis-inducing effect of an oxidative analogue of gambogic acid (GA) on the human hepatocellular carcinoma cell line HepG2 and explore the related molecular mechanisms. HepG2 cells were treated with the analogue of GA and the growth inhibition was analysed by MTT assay. The morphological changes in cells were observed under an inverted light microscope and a fluorescence microscope. In addition, both the cell-cycle arrest and the apoptosis rate were detected by flow cytometry. Western blot was used to evaluate the alteration of protein expression. The viability of HepG2 cells was markedly inhibited in a concentration-dependent manner and obvious morphological changes were confirmed, including condensed chromatin and reduced volume. Increased percentage of apoptotic cells was displayed and altered expression level of several apoptosis-associated proteins, P53, Bcl-2, Bax and pro-caspase-3, was obtained. The newly synthesized analogue of GA exhibited potential anticancer activity, induced remarkable apoptosis in HepG2 cells, probably through the intrinsic mitochondrial pathway, and promised to be a new candidate for future cancer therapy.

Through simplifying the complicated skeleton of the natural product gambogic acid, two series derivatives of chromone and xanthone were synthesized and examined for their antitumor activities against several cancer cells in vitro by MTT method. The results showed that appropriate introduction of prenyl group to the small molecular compounds could elevate their antitumor activities. The structure-activities relationship of synthesized compounds certified that the bridgecore in gambogic acid was very important for keeping its antitumor activities.

Resistance of cotton aphid (Aphis gossypii Glover) collected from four leading cotton producing regions and one non-cotton producing region in Shandong Province, China, in 1985, 1999, and 2004 to fenvalerate, omethoate, imidacloprid, acetamiprid, carbosulfan, and endosulfan, was determined on cotton (Gossypium hirsutum L.). Dose-response results indicate that A. gossypii became highly resistant to fenvalerate, and the resistance ratios (RRs) increased from 30–370-fold in 1985 to 370–2150-fold from different regions as compared with the susceptible population (S). A. gossypii also exhibited strong resistance to imidacloprid and acetamiprid with RRs of 17- to 97-fold in 2004. Resistance of A. gossypii to omethoate varied greatly among the five geographical regions, and the RRs ranged from 5- to 80-fold. In contrast, the resistance to carbosulfan did not significantly increase from 1999 to 2004 in all regions. The information from this study would be helpful for management of A. gossypii on cotton in those regions.

To explore the expression of PXR (Pregnane X receptor) in several malignant hematological cell lines, and to investigate the reversal effect of Gambogic acid (GA) on multi-drug resistance (MDR) of K562/A02 cell line and its reversal mechanism.Transcription of PXR was detected by real-time PCR in several malignant hematological cell lines. The growth inhibition rate of K562/A02 in different experimental groups was assayed by MTT method, and the expression of PXR protein was measured by Western blot.PXR gene transcription could be detected in several hematological malignancy cell lines, and it was significantly higher in K562/A02 cell line, compared with the other cell lines used in this experiment. Low-dose GA could enhance cell growth inhibition rate, increasing the effect of chemotherapy, which may be associated with down-regulation of PXR expression. PXR gene transcription and protein expression in GA and DNR+GA groups decreased as compared with control group and the DNR group, suggesting that low-dose GA can down-regulate PXR gene transcription and protein expression.PXR gene transcription can be detected in several hematological malignancy cell line, which is significantly higher in K562/A02 cell line, as compared with the other cell lines used in this experiment. Low-dose GA can enhance cell growth inhibition rate, increasing the effect of chemotherapy, which may be associated with down-regulation of PXR expression.

Liang Tian,1 Bao-an Chen,1 Jian Cheng,1 Qing-long Guo21Department of Hematology and Oncology (Key Department of Jiangsu Medicine), The Affiliated Zhongda Hospital, Medical School, Southeast University, 2China Pharmaceutical University, Nanjing, Jiangsu, People’s Republic of ChinaObjective: This study aims to investigate the potential benefit of combination therapy with magnetic nanoparticles of Fe3O4 (Fe3O4-MNP) and gambogic acid (GA) on SMMC-7721 cells.Methods: The inhibition of proliferation of SMMC-7721 cells was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell apoptosis was calculated and analyzed by flow cytometry, and the expressions of the apoptosis-related protein were detected by Western blot.Results: GA enhanced the cytotoxicity of SMMC-7721 cells in a dose-dependent manner. The Fe3O4-MNP itself had no obviously inhibitory effect, but it could enhance the effect of GA on proliferation of SMMC-7721 cells. The apoptotic rate of SMMC-7721 cells induced by combination of GA with Fe3O4-MNP was higher than that by GA alone. The expression levels of caspase-3 and caspase-8 after co-treatment of GA and Fe3O4-MNP were higher than that exposed to either GA or Fe3O4-MNP alone, while the levels of bcl-2 were downregulated.Conclusion: Fe3O4-MNP can promote GA-induced apoptosis of SMMC-7721 cells, which may be related to the downregulation of Bcl-2 and upregulation of caspase-3.Keywords: primary hepatocellular carcinoma, traditional Chinese medicine, anti-tumor activity, targeted-drug carrier

The overexpression of P-glycoprotein (P-gp) is associated with multidrug resistance (MDR) of tumor cells to a number of chemotherapeutic drugs. P-gp inhibitors have been shown to effectively reverse P-gp-mediated MDR in both in vitro and in vivo. Our previous studies demonstrated that E6, a novel synthetic calmodulin inhibitor, exhibited potent inhibitory effect on P-gp in rat brain microvessel endothelial cells (RBMECs). In the present study, the effect of E6 on MDR in a K562 MDR cell line (K562/DOX) highly expressing P-gp was studied and compared with that of a conventional P-gp inhibitor, verapamil (VER). E6 at concentrations of 1, 3, 10, 30 microM reduced the IC50 value of doxorubicin in K562/DOX cells from 79.19 microM to 35.18, 21.86, 6.31 and 1.97 microM, respectively. However, the IC50 value of doxorubicin in K562 sensitive subline was not significantly changed by E6. Using a DNA content analysis and an annexin V binding assay, the effects of E6 on doxorubicin-induced apoptosis were also examined. The results indicated that E6 effectively reversed the resistance to doxorubicin-induced apoptosis in K562/DOX cells. In addition, co-treatment of E6 and doxorubicin resulted in a remarkably G2/M blocking effect in K562/DOX cells. Furthermore, the treatment of K562/DOX cells with 10 microM E6 led to increased intracellular accumulation and decreased efflux of doxorubicin. Overall, the pharmacological effects of E6 on P-gp-mediated MDR is much stronger than that of positive control drug VER. These results suggested that E6 is a novel and potent MDR reversal agent and may be a potential adjunctive agent for tumor chemotherapy.

We determined the effect of baicalein on prostatic hyperplasia in experimental animal models. Prostatic hyperplasia was induced by testosterone propionate in mice and castrated rats and by transplantation of homologous strain fetal mice urogenital sinus in mice. With the histopathological examination, the efficacy of baicalein on prostate hyperplasia in experimental animals was evaluated by the activity of serum acid phosphatase (ACP) and the following norm of the prostate gland: the volume, wet weight, wet weight index, dry weight index, DNA contents and prostatic epithelial height and cavity diameter. Results showed that baicalein at doses of 260 and 130 mg/kg administrated intragastrically (i.g.) significantly inhibited prostatic hyperplasia in castrated rats induced by testosterone propionate compared with the negative control group (p

LW-213 is a derivative of Wogonin and the anticancer activities of Wogonin have been reported. To study whether LW-213 inhibits cancer cells and explore a possible mechanism, we investigate the compound in several cancer cell lines. We found LW-213 arrests G2/M cycle in breast cancer cells by suppression of Akt/Gsk3β/β-catenin signaling pathway. In compound treated cells, cell cycle-related proteins cyclin A, cyclin B1, p-CDK1, p-Cdc25C, and p-Chk2 (Thr68) were upregulated, and β-catenin nuclear translocation was inhibited. Electrophoretic mobility shift assay revealed LW-213 inhibits binding of β-catenin/LEF complex to DNA. GSK3β inhibitor LiCl and siRNA against GSK3β partially reversed G2/M arrest in breast cancer MCF-7 cells. These results suggest LW-213 triggered G2/M cell cycle arrest through suppression of β-catenin signaling. In BALB/c mice, growth of xenotransplanted MCF-7 tumor was also inhibited after treatment of LW-213. Regulation of cyclin A, cyclin B1, and β-catenin by LW-213 in vivo was the same as in vitro study. In conclusion, we found LW-213 exerts its anticancer effect on cell proliferation and cell cycle through repression of Akt/Gsk3β/β-catenin signaling pathway. LW-213 could be a potential candidate for anticancer drug development.

We recently establish that aspafilioside B, a steroidal saponin extracted from Asparagus filicinus, is an active cytotoxic component. However, its antitumor activity is till unknown. In this study, the anticancer effect of aspafilioside B against HCC cells and the underlying mechanisms were investigated. Our results showed that aspafilioside B inhibited the growth and proliferation of HCC cell lines. Further study revealed that aspafilioside B could significantly induce G2 phase cell cycle arrest and apoptosis, accompanying the accumulation of reactive oxygen species (ROS), but blocking ROS generation with N-acetyl-l-cysteine (NAC) could not prevent G2/M arrest and apoptosis. Additionally, treatment with aspafilioside B induced phosphorylation of extracellular signal-regulated kinase (ERK) and p38 MAP kinase. Moreover, both ERK inhibitor PD98059 and p38 inhibitor SB203580 almost abolished the G2/M phase arrest and apoptosis induced by aspafilioside B, and reversed the expression of cell cycle- and apoptosis-related proteins. We also found that aspafilioside B treatment increased both Ras and Raf activation, and transfection of cells with H-Ras and N-Ras shRNA almost attenuated aspafilioside B-induced G2 phase arrest and apoptosis as well as the ERK and p38 activation. Finally, in vivo, aspafilioside B suppressed tumor growth in mouse xenograft models, and the mechanism was the same as in vitro study. Collectively, these findings indicated that aspafilioside B may up-regulate H-Ras and N-Ras, causing c-Raf phosphorylation, and lead to ERK and p38 activation, which consequently induced the G2 phase arrest and apoptosis. This study provides the evidence that aspafilioside B is a promising therapeutic agent against HCC.

Increasing evidence from various clinical and experimental studies has demonstrated that the inflammatory microenvironment facilitates tumor metastasis. Clinically, it will be a promising choice to suppress tumor metastasis by targeting inflammatory microenvironment. Our previous studies have demonstrated that wogonin (a bioflavonoid isolated from the traditional Chinese medicine of Huang-Qin) possesses the anti-metastatic and anti-inflammatory activity, but we have little idea about its efficacy on inflammatory-induced tumor metastasis and the mechanism underlying it. In this study, we focused on epithelial mesenchymal transition (EMT), the first step of tumor metastasis, to evaluate the effects of wogonin on tumor metastasis in inflammatory microenvironment. We found that wogonin inhibited THP-1 conditioned-medium- (CM-) and IL-6-induced EMT by inactivating STAT3 signal. And in wogonin-treated A549 cells which pretreated with THP-1 CM or IL-6, the expression level of E-cadherin, an EMT negative biomarker, increased while that of N-cadherin, Vimentin, and EMT-related transcription factors including Snail and Twist decreased. Moreover, wogonin inhibited IL-6-induced phosphorylation of STAT3, prevented p-STAT3 dimer translocation into the nucleus, and suppressed the DNA-binding activity of p-STAT3. Interestingly, similar results were obtained in the tumor xenografts mice, including downregulation of p-STAT3, N-cadherin, and Vimentin while up-regulation of E-cadherin. Wogonin also inhibit the metastasis of A549 cells in vivo. Taken all data together, we concluded that wogonin suppresses tumor cells migration in inflammatory microenvironment by inactivating STAT3 signal.

Picroside II, separated from Chinese herbal medicine, is an active compound with neroprotective activity. Molecularly imprinted polymers (MIPs) have high affinity toward template molecules synthesized by molecularly imprinted technology for its specific combined sites, which can overcome the shortcomings of traditional separation methods, such as complex operation and low efficiency. In this paper, MIPs were prepared by precipitation polymerization with picroside II as the template molecule, 1-vinylimidazole (1-Vinyl) as functional monomer, ethylene glycol dimethacrylate (EDMA) as cross-linker. The morphology of MIPs was characterized by scanning electronmicroscope (SEM) and its static adsorption capacity was measured by the scatchard equation. The results showed that picroside II MIPs have spherical shape, and most of them are uniform in size. Furthermore, the maximum binding capacity (Q(max)) of MIPs is 3.02 mg x g(-1), higher than that of non-imprinted polymers (NIPs). This result indicated that picroside II MIPs with good morphology and high targeted affinity toward the template molecules can be prepared by precipitation polymerization, which can be used to separate picroside II and its analogies from extract of Chinese herbal medicine. In addition, this method has the advantages of good environment and simple operation, which might offer a novel method for the efficient separation of picroside II in the traditional herbal medicines.

Gamboge, the resin of Garcinia hanburyi has had a long history of use as the traditional dye as well as a complementary and alternative medicine. The antitumor activities of gamboge have been well demonstrated by inhibiting the growth and progression of cancer cells both in vitro and in vivo. In order to further clarify the mode of action of gamboge, there are three key questions needed to be answered, including what's in gamboge? How do the chemical components from gamboge work on cancer cells? How do biological systems work on the chemical components from gamboge after administration? In this review, we summarize the explorations of the answers toward these questions according to the recent progress in both of chemistry and biology research of gamboge. In addition, the implication in the future research and discovery of the caged G. xanthones as anticancer agents is also discussed.

The aim of this study was to explore the effect of gambogic acid (GA) on MDS SKM-1 cell proliferation, apoptosis and their possible mechanism. Cell proliferation was determined by MTT method. The apoptosis percentage and cell cycle regulation of SKM-1 cells were analyzed by flow cytometry. Morphological features were observed by light microscopy. The mRNA expression of bcl-2 and bax were detected by RT-PCR. The results showed that GA could inhibit the proliferation of SKM-1 cells in a dose- and time-dependent manner (IC50 was 0.37 µg/ml at 48 h), increase the apoptotic percentage of SKM-1 cells, and arrest cell cycle at the G0/G1. The expression of bax mRNA was up-regulated while that of bcl-2 mRNA was down-regulated in SKM-1 cells treated with GA for 48 h. It is concluded that GA can induce apoptosis, which may be related to its effect of arresting cells at phase of G0/G1 and down-regulating bcl-2/bax ratio.

Hypoxia induced drug resistance is a major obstacle in the development of effective cancer therapy. In the present study, the reversal abilities of wogonin on the hypoxia resistance and the underlying mechanisms were discovered. MTT assay revealed that hypoxia increased maximal 1.71-, 2.08-, and 2.15-fold of IC50 toward paclitaxel, ADM, and DDP in human colon cancer cell lines HCT116, respectively. Furthermore, wogonin showed strong reversal potency in HCT116 cells in hypoxia and the RF reached 2.05. hypoxia-inducible factor-1α (HIF-1α) can activate the expression of target genes involved in glycolysis. Wogonin decreased the expression of glycolysis-related proteins (HKII, PDHK1, LDHA), glucose uptake, and lactate generation in a dose-dependent manner. Further, Western blot experiments exhibited that wogonin could down regulate HIF-1α expression and glycolysis through inhibiting PI3K/Akt signaling pathway, which might be the mechanism of reversal resistance of wogonin. Also, wogonin could inhibit the growth of transplantable tumors and the expression of HIF-1α, glycolysis-related proteins and PI3K/Akt in vivo. In summary, wogonin could be a good candidate for the development of new multidrug resistance (MDR) reversal agent and its reversal mechanism probably is due to the suppression of HIF-1α expression via inhibiting PI3K/Akt signaling pathway.

Many plant-derived natural components have been recognized as effective in the treatment of human diseases. Baicalein (5,6,7-trihydroxyflavone) is one of the primary active components of Scutellaria species, and is well known ingredient in traditional Chinese medicine (TCM) and oriental medicine. Numerous studies have reported that baicalein possesses multiple pharmacological functions, such as anticancer, antioxidant, anti-inflammatory, neuroprotective, hepatoprotective, and antimicrobial properties. The cardioprotective effect of baicalein has been proved in several cell culture and small animal models. This review addresses the recent findings of cardioprotective potentials of baicalein in vitro and in vivo

Tumor necrosis factor-α (TNF-α) is being used as an antineoplastic agent in treatment regimens of patients with locally advanced solid tumors, but TNF-α alone is only marginally active. In clinical use, it is usually combined with other chemical agents to increase its tumor response rate. Our previous studies reported that LYG-202 (5-hydroxy-8-methoxy-7-(4-(4-methylpiperazin-1-yl)butoxy)-2-phenyl-4H-chromen-4-one), a synthesized flavonoid with a piperazine substitution, has antiproliferative, antiangiogenic, and proapoptotic activities in multiple cancer cell lines. Here we evaluated the antineoplastic effect of TNF-α and analyzed the mechanism underlying its combination with LYG-202. Our results indicated that LYG-202 significantly increased the cytostatic and proapoptotic activity of TNF-α in HepG2 cells and heightened the protein level of apoptosis-related genes including caspase-3, caspase-8/9, cleaved poly(ADP-ribose) polymerase, and Bid. The fact that LYG-202 had a fitness score similar to that of the casein kinase 2 (CK2) inhibitor naphthyridine-8-carboxylate (CX-4945) implied to us that it may serve as a potential candidate for CK2 inhibitor, and the kinase activity assay suggested that LYG-202 significantly inhibited CK2 activity. Moreover, the electrophoretic mobility shift assay and luciferase assay showed that LYG-202 blocked the TNF-α-induced nuclear factor-κB (NF-κB) survival signaling pathway primarily by inactivating protein kinase CK2. In murine xenograft models, we also found that LYG-202 enhanced TNF-α antineoplastic activity and inhibited CK2 activity and NF-κB-regulated antiapoptotic gene expression. All these results showed that LYG-202 enhanced TNF-α-induced apoptosis by attenuating the CK2-dependent NF-κB pathway and probably is a promising agent in combination with TNF-α.

This study was purposed to investigate the reversal effect of gambogic acid (GA) on multidrug resistance of K562/A02 cells and its mechanism. The IC(50) (half maximal inhibitory concentration) of adriamycin (ADM) was evaluated by MTT. Cell apoptosis was detected by flow cytometry. Morphological changes of K562/A02 cells were observed by fluorescent microscopy with DAPI staining. The expressions of Survivin and P-gp were determined by Western blot. The results showed that the IC(50) of ADM on K562 and K562/A02 cell proliferation were (1.42 ± 0.07) µg/ml and (28.42 ± 1.40) µg/ml respectively. GA ≤ 0.0625 µmol/L had no inhibitory effect on proliferation of K562 and K562/A02. 0.0625 µmol/L GA could enhance the sensitivity of K562/A02 cells to ADM (P0.05) and the reversal multiples was 1.53. The apoptotic rate was raised after treating with ADM combined with 0.0625 µmol/L GA for 48 h (P0.05). Morphological differences were typical and obvious between cells of control and treated groups under fluorescence microscopy using DAPI staining. After treating K562/A02 cells with ADM combined with 0.0625 µmol/L GA for 48 h, the expressions of Survivin and P-gp were down-regulated at protein levels. It is concluded that GA can enhance the sensitivity of K562/A02 cells to ADM, which may be related to increasing cell apoptosis and down-regulating expressions of Survivin and P-gp.

Increasing evidence suggests that inflammatory microenvironment plays a critical role at different stages of tumor development. However, the molecular mechanisms of the interaction between inflammation and proliferation of cancer cells remain poorly defined. Here we reported the inhibitory effects of oroxylin A on the inflammation-stimulated proliferation of tumor cells and delineated the mechanism of its action. The results indicated that treatment with oroxylin A inhibited NF-κB p65 nuclear translocation and phosphorylation of IκBα and IKKα/β in both human colon tumor HCT116 cells and human monocytes THP-1 cells. In addition, in THP-1 cells, oroxylin A significantly suppressed lipopolysaccharide (LPS)-induced secretion of prototypical proinflammatory cytokine IL-6 but not IL-1β, and it was confirmed at the transcription level. Moreover, oroxylin A inhibited the proliferation of HCT116 cells stimulated by LPS-induced THP-1 cells in co-culture microenvironment. In summary, oroxylin A modulated NF-κB signaling pathway involved in inflammation-induced cancer initiation and progression and therefore could be a potential cancer chemoprevention agent for inflammation-related cancer.

The selective induction of apoptosis of gambogic acid (GA) on MGC-803 cells and its probable molecular mechanism were studied. GA greatly inhibited (24, 48, 72 h) the growth of MGC-803 cells (by MTT); the IC(50) value was 0.96 microg/ml at 48 h. Meanwhile, no influence was observed on body weight, number of WBC (white blood cells) in blood or karyote in marrow of rats after GA was injected intravenously. We conclude that GA does not affect normal cells, but that it can induce apoptosis in tumor cells selectively and there were marked morphological changes. A great quantity of apoptotic cells and increasing G(2)/M phase cells were observed by flow cytometry, and a significant percentage of early apoptotic cells were observed by Annexin-V/PI double staining assay. The increase of bax gene and the decrease of bc1-2 gene expressions were detected by immunohistochemistry. Activation of bax and suppression of bc1-2 may contribute to the apoptosis mechanism.

To study the inhibitory effect of general gambogic acids (GGA) on transplantation tumor SMMC-7721 in experimental animal model and SMMC-7721 cells in vitro.Anti-tumor activity of GGA in the experimental transplantation tumor SMMC-7721 was evaluated by relative tumor growth ratio. Cell morphology was observed with inverted microscope and electron microscope. Cell proliferation was measured by MTT assay and the telomerase activity was determined by PCR.In vivo study indicated that GGA (2, 4, and 8 mg/kg, iv, 3 times per week for 3 weeks) displayed an inhibitory effect on the growth of transplantation tumor SMMC-7721 in nude mice compared with the normal saline group (P0.01). At the concentrations of 0.625-5.0 mg/L, GGA remarkably inhibited the proliferation of SMMC-7721 cells in vitro. GGA 2 mg/L dramatically changed morphology of SMMC-7721 cells and inhibited the telomerase activity in SMMC-7721 cells.GGA had inhibitory effect on the growth of SMMC-7721, which might be related to its inhibition of telomerase activity.

To investigate the antitumor effect of recombinant L-asparaginase on the growth of several tumors such as P388, L1210, hepatocellular carcinoma (Heps), K562, P815, and sarcoma 180 (S180).Tumor cells (K562, L1210, and P815) were cultured in vitro and the morphology of those cells was observed with inverse microscope and transmission electron microscope. MTT assay was performed to measure the cell proliferation and inhibition rate. DNA content was assayed by flow cytometry. According to protocols of transplant tumor research, mice were transplanted with tumor cells L1210, P388, Heps, and S180. The survival rate and weight of tumor were observed after the treatment of test drugs.The antitumor effects of L-asparaginase were observed in vitro with tumor cells K562, L1210, and P815 (P0.01). In vivo experiments showed that ip administration of L-asparaginase significantly increased the survival rate and life span of mice with P388 or L1210 tumor cells (P0.01). Tumor growth induced with Heps was also significantly suppressed. Furthermore, significant suppression of tumor growth was observed in mice induced with Heps and S180 by iv administration of L-asparaginase.Recombinant L-asparaginase markedly inhibited tumors tested in this study and the results strongly suggest that recombinant L-asparaginase has great potential for clinical treatment of these tumors.

Jian Cheng,1,* Lin Cheng,1,* Baoan Chen,1,2 Guohua Xia,1 Chong Gao,1 Huihui Song,1 Wen Bao,1 Qinglong Guo,3 Haiwei Zhang,3 Xuemei Wang41Department of Hematology, Key Medical Disciplines of Jiangsu Province, Zhongda Hospital, Medical School of Southeast University, 2Department of Oncology of Southeast University, 3Key Laboratory of Carcinogenesis and Intervention of Jiangsu Province, China Pharmaceutical University, 4State Key Laboratory of Bioelectronics, Southeast University, Nanjing, People's Republic of China *These authors contributed equally to this workBackground: Multidrug resistance is the main obstacle to the efficiency of systemic chemotherapy against hematologic malignancy. This study investigated the reversible effect of the copolymer wogonin and daunorubicin coloaded into Fe3O4 magnetic anoparticles, and the mechanism potentially involved.Methods: The growth inhibition rate of K562/A02 cells was investigated by MTT assay, and apoptosis of cells and the intracellular daunorubicin concentration were detected by flow cytometry. Distribution of nanoparticles taken up by K562/A02 cells was observed under a transmission electron microscope and demonstrated by Prussian blue staining. The transcription level of MDR1 mRNA and expression of P-glycoprotein were determined by reverse transcriptase polymerase chain reaction and Western blotting assay, respectively.Results: The reversible effect of daunorubicin-wogonin magnetic nanoparticles was 8.87-fold that of daunorubicin + wogonin and of daunorubicin magnetic nanoparticles. Transmission electron microscopy and Prussian blue staining revealed that the nanoparticles were located in the endosome vesicles of cytoplasm. Also, the apoptosis rate and accumulation of intracellular daunorubicin in the daunorubicin-wogonin magnetic nanoparticle group were significantly higher than that in the daunorubicin, daunorubicin + wogonin, and daunorubicin magnetic nanoparticle groups. Furthermore, transcription of MDR1 mRNA and expression of P-glycoprotein in K562/A02 cells were significantly downregulated in the daunorubicin-wogonin magnetic nanoparticle group compared with the other groups.Conclusion: These findings suggest that the remarkable effects of the novel daunorubicin-wogonin magnetic nanoparticle formulation on multidrug resistant K562/A02 leukemia cells would be a promising strategy for overcoming multidrug resistance.Keywords: magnetic nanoparticles, Fe3O4, wogonin, multidrug resistance, daunorubicin, P-glycoprotein