Downregulation of monocarboxylate transporter 1 inhibits the invasion and migration through suppression of the PI3K/Akt signaling pathway in human nasopharyngeal carcinoma cells.

Monocarboxylate transporter 1 (MCT1) has been reported to be correlated wtih decreased survival and advanced stage of progression in a series of human tumor cells and primary cancers. Specifically, MCT1 has been documented to be involved in tumor progression, including invasion and migration. Here, we investigated the mechanism and effect of regulation of MCT1 on invasion and migration of nasopharyngeal carcinoma (NPC) cells. In the study, we firstly demonstrated that the expression of MCT1 in CNE2Z cells was obviously higher than that in HNE1 cells. Downregulation of MCT1 inhibited the invasion and migration in CNE2Z cells, upregulated the expression of E-cadherin, TIMP (tissue inhibitor of metalloproteinase)-2 and TIMP-1, and suppressed the expression of matrix metalloproteinases (MMP)-9 and MMP-2. Correspondingly, upregulation of MCT1 enhanced the invasive and migratory potential in HNE1 cells, increased the expression of MMP-9 and MMP-2, and downregulated the expression of E-cadherin, TIMP-2 and TIMP-1. The mechanistic study demonstrated that the effect of MCT1 might be correlated with PI3K/Akt signaling pathway. LY294002, a PI3K inhibitor, increased the inhibition of invasion and migration mediated by downregulation of MCT1 in CNE2Z cells. These findings collectively suggested that MCT1 might act as a new regulator to improve invasion and migration of NPC cells and be correlated with activating the PI3K/Akt pathway.

Synergistic antitumor effect of 3-bromopyruvate and 5-fluorouracil against human colorectal cancer through cell cycle arrest and induction of apoptosis.

3-Bromopyruvic acid (3-BP) is a well-known inhibitor of energy metabolism. It has been proposed as an anticancer agent as well as a chemosensitizer for use in combination with anticancer drugs. 5-Fluorouracil (5-FU) is the first-line chemotherapeutic agent for colorectal cancer; however, most patients develop resistance to 5-FU through various mechanisms. The aim of this study was to investigate whether 3-BP has a synergistic antitumor effect with 5-FU on human colorectal cancer cells. In our study, combined 3-BP and 5-FU treatment upregulated p53 and p21, whereas cyclin-dependent kinase CDK4 and CDK2 were downregulated, which led to G0/G1 phase arrest. Furthermore, there was an increase in reactive oxygen species levels and a decrease in adenosine triphosphate levels. It was also observed that Bax expression increased, whereas Bcl-2 expression reduced, which were indicative of mitochondria-dependent apoptosis. In addition, the combination of 3-BP and 5-FU significantly suppressed tumor growth in the BALB/c mice in vivo. Therefore, 3-BP inhibits tumor proliferation and induces S and G2/M phase arrest. It also exerts a synergistic antitumor effect with 5-FU on SW480 cells.

[Effect of oridonin on apoptosis and intracellular reactive oxygen species level in triple-negative breast cancer MDA-MB-231 cells].

Oridonin, which is an ent-kaurene diterpenoid isolated from traditional Chinese medicine Rabdosia rubescens, displays various bioactivities, including anti-inflammation, anti-bacteria and anti-tumor. This study aimed to investigate the effect of oridonin on apoptosis of triple-negative breast cancer MDA-MB-231 cells and its underlying mechanisms. The inhibitory effect of oridonin on proliferation of MDA-MB-231 cells was measured by MTT assay; Apoptosis was analyzed by flow cytometry with PI staining and Annexin V-FITC/PI staining; Intracellular reactive oxygen species (ROS) level was determined by ROS detection kit, and expressions of PARP, Bcl-2, caspase-3 were analyzed by Western blot. The results showed that oridonin exhibited a significant effect in inducing apoptosis of MDA-MB-231 cells, enhancing intracellular ROS level, down-regulating expression of Bcl-2 protein, and promoting cleavage of caspase-3 and its substrate PARP. These results indicated that the apoptosis-inducing effect of oridonin on MDA-MB-231 cells might be correlated with increase of intracellular ROS level, down-regulation of Bcl-2 protein and activation of caspase-3.

[Effects of LCL161, a Smac mimetic on the proliferation and apoptosis in hepatocellular carcinoma cells].

OBJECTIVE: To investigate the effects of LCL161, a Smac mimetic, on the proliferation and apoptosis in hepatocellular carcinoma cells and the underlying mechanisms. 
 METHODS: The effect of LCL161 on the cell viability of HepG2 and SMMC7721 cells was measured by MTT assay. The effect of LCL161 at lower concentrations on the proliferation in hepatocellular carcinoma (HCC) cells was detected by colony formation assay. Apoptosis was assessed by flow cytometry with PI staining. The mitochondrial membrane potential was measured by JC-1 staining. The expression of PARP, p-Akt, cIAP1 and XIAP protein was analyzed by Western blot.
 RESULTS: LCL161 displayed notable antiproliferative activity on HCC cells at the concentrations of 1-16 µmol/L (P<0.01), with IC50 values of 4.3 and 4.9 µmol/L for HepG2 and SMMC7721 cells, respectively, after treatment for 48 h. LCL161 at lower concentrations obviously inhibited the colony formation of HCC cells. LCL161 induced significant apoptosis in HCC cells (P<0.01), and resulted in the apoptotic rate at (1.5±0.8)% or (1.8±0.6)% , (15.2±2.8)% or (12.2±2.4)%, (28.7±3.0)% or (22.4±2.7)%, (34.6±2.3)% or (30.2±2.4)% for HepG2 cells or SMMC7721 cells at the concentration of 0, 2, 4 or 8 µmol/L, respectively. The result of JC-1 staining indicated that the mitochondrial membrane potential of HCC cells was reduced by LCL161. In addition, LCL161 promoted the cleavage of PARP, down-regulated the protein expression of p-Akt, and degraded cIAP1.
 CONCLUSION: LCL161 possesses significant anti-proliferative activity and pro-apoptotic action in HepG2 and SMMC7721 cells, which might be correlated with reduction in mitochondrial membrane potential, down-regulation of p-Akt and degradation of cIAP1.

17-Demethoxy-reblastatin, an Hsp90 inhibitor, induces mitochondria-mediated apoptosis through downregulation of Mcl-1 in human hepatocellular carcinoma cells.

Heat shock protein 90 (Hsp90) is an attractive therapeutic target. Geldanamycin (GA), the first identified Hsp90 inhibitor, exhibited potent antitumor activity, but possessed significant hepatotoxicity. To overcome the hepatotoxicity derived from the quinone structure of GA, a non-quinone GA derivative 17-demethoxy-reblastatin (17-DR) was obtained from a genetically modified strain of Streptomyces hygroscopicus. In the present study, we examined the anticancer effects of 17-DR on human hepatocellular carcinoma (HCC) cell lines HepG2 and SMMC7721, and its underlying mechanisms. The results indicated that 17-DR could concentration-dependently inhibit the proliferation, and decrease the colony formation in HCC cells. It also induced significant apoptosis in HCC cells, which was mediated by mitochondria via a caspase-dependent pathway. The mechanisms involved in 17-DR-induced apoptosis included the downregulation of myeloid cell leukemia-1 (Mcl-1), and upregulation of Bcl-2 antagonist killer 1 (Bak). And the upregulated Bak expression resulted from downregulation of Mcl-1 played an essential role in this process. Taken together, these results indicated that 17-DR possessed potent anticancer effects on HCC cells by inhibiting cell proliferation and inducing apoptosis.

Mechanisms underlying 3-bromopyruvate-induced cell death in colon cancer.

3-Bromopyruvate (3BP) is an energy-depleting drug that inhibits Hexokinase II activity by alkylation during glycolysis, thereby suppressing the production of ATP and inducing cell death. As such, 3BP can potentially serve as an anti-tumorigenic agent. Our previous research showed that 3BP can induce apoptosis via AKT /protein Kinase B signaling in breast cancer cells. Here we found that 3BP can also induce colon cancer cell death by necroptosis and apoptosis at the same time and concentration in the SW480 and HT29 cell lines; in the latter, autophagy was also found to be a mechanism of cell death. In HT29 cells, combined treatment with 3BP and the autophagy inhibitor 3-methyladenine (3-MA) exacerbated cell death, while viability in 3BP-treated cells was enhanced by concomitant treatment with the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp fluoromethylketone (z-VAD-fmk) and the necroptosis inhibitor necrostatin (Nec)-1. Moreover, 3BP inhibited tumor growth in a SW480 xenograft mouse model. These results indicate that 3BP can suppress tumor growth and induce cell death by multiple mechanisms at the same time and concentration in different types of colon cancer cell by depleting cellular energy stores.

3-Bromopyruvate induces apoptosis in breast cancer cells by downregulating Mcl-1 through the PI3K/Akt signaling pathway.

The hexokinase inhibitor 3-bromopyruvate (3-BrPA) can inhibit glycolysis in tumor cells to reduce ATP production, resulting in apoptosis. However, as 3-BrPA is an alkylating agent, its cytotoxic action may be induced by other molecular mechanisms. The results presented here reveal that 3-BrPA-induced apoptosis is caspase independent. Further, 3-BrPA induces the generation of reactive oxygen species in MDA-MB-231 cells, leading to mitochondria-mediated apoptosis. These results suggest that caspase-independent apoptosis may be induced by the generation of reactive oxygen species. In this study, we also demonstrated that 3-BrPA induces apoptosis through the downregulation of myeloid cell leukemia-1 (Mcl-1) in MDA-MB-231 breast cancer cells. The results of Mcl-1 knockdown indicate that Mcl-1 plays an important role in 3-BrPA-induced apoptosis. Further, the upregulation of Mcl-1 expression in 3-BrPA-treated MDA-MB-231 cells significantly increases cell viability. In addition, 3-BrPA treatment resulted in the downregulation of p-Akt, suggesting that 3-BrPA may downregulate Mcl-1 through the phosphoinositide-3-kinase/Akt pathway. These findings indicate that 3-BrPA induces apoptosis in breast cancer cells by downregulating Mcl-1 through the phosphoinositide-3-kinase/Akt signaling pathway.

[Corrigendum] 3­Bromopyruvate sensitizes human breast cancer cells to TRAIL­induced apoptosis via the phosphorylated AMPK­mediated upregulation of DR5.

Following the publication of this article, an interested reader drew to the authors' attention that the western blotting data shown in Fig. 3 on. p. 2439 contained apparent anomalies; first, the protein bands shown to represent the CHOP and p­AMPK experiments in Fig. 3A were strikingly similar. Secondly, the same data bands were inadvertently included in the figure to represent the GRP78 and Bax experiments for the MCF­7 group. The authors have re­examined their original data and realized that this figure was assembled incorrectly (the CHOP and GRP78 data were inadvertently duplicated in the figure). The corrected version of Fig. 3, showing the correct data for the p­AMPK and Bax experiments for the MCF­7 group in Fig. 3A, is shown on the next page. The authors sincerely apologize for the error that was introduced during the preparation of this figure, thank the Editor of Oncology Reports for granting them the opportunity to publish a Corrigendum, and are grateful to the reader for alerting them to this issue. The authors also regret any inconvenience that this mistake may have caused. [the original article was published in Oncology Reports 40: 2435­2444, 2018; DOI: 10.3892/or.2018.6644].

Ppm1b Negatively Regulates 3-Bromopyruvate Induced Necroptosis in Breast Cancer Cells.

Up to 30% of breast cancer mortality is caused by cancer relapse despite primary clinical treatments due to distant metastases. Further research focusing on breast cancer mechanisms are needed for deeper understanding of disease prognosis. 3-bromopyruvate (3-BP), a glycolysis inhibitor, has been studied as one of the antitumor agents in recent years. In this report, we want to investigate the form of cell death induced by 3-BP and demonstrate the inhibitory effect of 3-BP on breast cancer cell proliferation and its mechanism in vivo and in vitro. We found that 3-BP could inhibit MDA-MB-231 and MCF-7 breast cancer cell proliferation, through energy metabolism inhibition. Further, necroptosis characters in MDA-MB-231 cells after 3-BP treatment were observed, which could be negatively regulated through Ppm1b by dephosphorylation of RIP3. In addition, 3-BP treatment in an MDA-MB-231 cell-transplanted mouse model showed a significant antitumor effect, which correlated with necroptosis-related protein Ppm1b. The findings demonstrate the potential for 3-BP in the treatment of breast cancer, providing impetus for further clinical studies.

Metformin enhances the sensitivity of colorectal cancer cells to cisplatin through ROS-mediated PI3K/Akt signaling pathway.

Metformin and cisplatin have been widely studied as antitumor agents. However, the effect of metformin combined with cisplatin has not been investigated in colorectal cancer (CRC) cells. This study was aimed to explore the effect of metformin or/and cisplatin on cell viability, apoptosis, and the related signaling pathways in CRC SW480 and SW620 cells. We found that metformin or cisplatin inhibited cell viability of SW480 and SW620 cells in a concentration- and time-dependent manner. Furthermore, metformin combined with cisplatin obviously inhibited cell viability, decreased colony formation, induced apoptosis, mediated cleavage of caspase-9, caspase-3 and PARP, activated mitochondrial membrane potential, downregulated Mcl-1 and Bcl-2 expression, upregulated Bak and Bax expression, and increased reactive oxygen species (ROS) production, compared to the individual agent in SW480 and SW620 cells, which were attenuated by N-acetyl-L-cysteine (NAC), a ROS scavenger. Moreover, NAC could recover the downregulation of p-PI3K and p-Akt treated with combination of metformin and cisplatin, which subsequently activated the PI3K/Akt signaling pathway. Taken together, our results demonstrated that metformin enhanced the sensitivity of CRC cells to cisplatin through ROS-mediated PI3K/Akt signaling pathway.

[Down-regulation of miR-205-5p enhances pro-apoptotic effect of 3-bromopyruvate on human nasopharyngeal carcinoma CNE2Z cells].

OBJECTIVE: To investigate the effect of down-regulation of miR-205-5p on 3-bromopyruvate-induced apoptosis in human nasopharyngeal carcinoma CNE2Z cells. METHODS: Nasopharyngeal carcinoma CNE2Z cells were transfected with miR- 205-5p-mimic or miR-205-5p-inhibitor, treated with 80 µmol/L 3-bromopyruvate alone, or exposed to both of the treatments. The proliferation of the treated cells was examined with MTT assay, and early apoptosis of the cells was detected using a mitochondrial membrane potential detection kit (JC-1). DAPI fluorescence staining was used to detect morphological changes of the cell nuclei and late cell apoptosis; Annexin V-FITC/PI double staining was employed to detect the cell apoptosis rate. Western blotting was used to detect the expressions of Bcl-2, Bax, Mcl-1 and Bak proteins. RESULTS: Exposure to 3-bromopyruvate significantly inhibited the proliferation of CNE2Z cells, and increasing the drug concentration and extending the treatment time produced stronger inhibitory effects. Treatment with 80 µmol/L 3-bromopyruvate for 24, 48 and 72 h resulted in inhibition rates of (45.7±1.21)%, (64.4±2.02)% and (78.3±1.55)% in non-transfected CNE2Z cells, respectively; the inhibition rates were (27.7±1.04)%, (34.8±2.10)% and (44.3±1.57)% in the cells transfected with miR-205-5p-mimic, and were (80.5 ± 0.94)%, (87.9 ± 0.50)% and (93.8 ± 1.16)% in cells transfected with miR-205-5p-inhibitor, respectively. The results of mitochondrial membrane potential detection showed that the relative proportion of red and green fluorescence decreased significantly in miR-205-5p-inhibitor-transfected cells with 3-bromopyruvate treatment. Combined treatment of the cells with 3-bromopyruvate and miR-205-5p-inhibitor transfection obviously increased nuclear fragmentation and nuclear pyknosis and significantly increased cell apoptotic rate as compared with the two treatments alone (P < 0.01), causing also decreased expressions of Bcl-2 and Mcl-1 proteins and increased expressions of Bax and Bak proteins. CONCLUSIONS: Inhibition of miR-205-5p enhances the proapototic effect of 3-bromopyruvate in CNE2Z cells possibly in relation to the down-regulation of Mcl-1 and Bcl-2 and the up-regulation of Bak and Bax proteins.

miR-205-5p regulates epithelial-mesenchymal transition by targeting PTEN via PI3K/AKT signaling pathway in cisplatin-resistant nasopharyngeal carcinoma cells.

Epithelial-mesenchymal transition (EMT) symbolizes the predominant program of advanced-stage cancer, it is critical in cancer progression, metastasis, and chemotherapy resistance. In this study, the metastatic properties of nasopharyngeal carcinoma (NPC) cells were evaluated by morphological examination, wound healing assay, migration and invasion assay. Western blotting and qRT-PCR were used to ascertain the expression of markers which were associated with EMT. The effects of miR-205-5p on invasion, migration, EMT and proliferation of NPC cells were evaluated and the molecular mechanisms of their interaction were explored. In this study, we manifested firstly that the expression of miR-205-5p in cisplatin-resistant NPC cell line HNE1/DDP was obviously up-regulated than that in its parental cell line HNE1. Then we analyzed the specific role of miR-205-5p through functional assays by transfecting specific mimics and inhibitors. The results indicated that low expression of miR-205-5p restrained EMT progression of HNE1/DDP cells. Further studies on the mechanism of miR-205-5p manifested that PTEN was a downstream candidate gene of miR-205-5p, down-regulated PTEN expression could counteract the effect of miR-205-5p inhibitors, and the regulation of EMT by miR-205-5p on HNE1/DDP cells depended on the PI3K/AKT signaling pathway. Overall, our results indicated that miR-205-5p was targeting PTEN to regulate EMT through the PI3K/AKT pathway. This study will supply a new treatment target for advanced NPC.

[Knocking down fascin inhibits cervical cancer cell proliferation and tumorigenesis in nude mice].

OBJECTIVE: To study the effect of knocking down fascin on cervical cancer cell proliferation and tumorigenicity in nude mice. METHODS: Cervical cancer CaSki cells were infected with a lentiviral vector carrying fascin siRNA or with a negative control lentivirus, and fascin mRNA and protein expressions in the cells were detected using qRT-PCR and Western blotting. MTT assay was used to determine the proliferation of CaSki cells with fascin knockdown. CaSki cells transfected with fascin siRNA or the control lentiviral vector and non-transfected CaSki cells were inoculated subcutaneously in nude mice, and the volume and weight of the transplanted tumor were measured; Western blotting was used to detect the expressions of proliferating cell nuclear antigen (PCNA), survivin, cyclin dependent kinase 4 (CDK4) and p21 proteins in the tumor xenograft. RESULTS: Infection with the lentiviral vector carrying fascin siRNA, but not the negative control vector, caused significant reductions in the expression levels of fascin mRNA and protein in CaSki cells (P < 0.05). Fascin knockdown resulted in significantly reduced proliferation of CaSki cells in vitro (P < 0.05). The nude mice inoculated with CaSki cells with fascin knockdown showed reduced tumor volume and weight, lowered levels of PCNA, survivin and CDK4, and increased expression of p21 protein in the tumor xenograft compared with the control mice. The negative control lentivirus did not affect the proliferation or tumorigenicity of CaSki cells in nude mice or the expression levels of PCNA, survivin, CDK4 or p21 proteins in the xenografts. CONCLUSIONS: Knocking down fascin can inhibit the growth and tumorigenicity of cervical cancer cells in nude mice.

3­Bromopyruvate sensitizes human breast cancer cells to TRAIL­induced apoptosis via the phosphorylated AMPK­mediated upregulation of DR5.

Previous studies have indicated that the sensitivity of breast cancer cells to tumor necrosis factor­related apoptosis­inducing ligand (TRAIL)­induced apoptosis is associated with the expression of death receptors on the cell membrane. However, drug resistance limits the use of TRAIL in cancer therapy. Numerous studies have indicated that death receptors, which induce apoptosis, are upregulated by the endoplasmic reticulum (ER) stress response. 3­Bromopyruvate (3­BP), an anticancer agent, inhibits cell growth and induces apoptosis through interfering with glycolysis. In the present study, it was demonstrated that 3­BP synergistically sensitized breast cancer cells to TRAIL­induced apoptosis via the upregulation of death receptor 5 (DR5). Furthermore, we found that the protein levels of glucose­related protein 78 (GRP78) and CCAAT­enhancer­binding protein homologous protein (CHOP) increased following treatment with 3­BP. The expression of Bax (in MCF­7 cells) and caspase­3 (in MDA­MB­231 cells) increased following co­treatment with 3­BP and TRAIL, whereas the expression of the anti­apoptotic protein Bcl­2 decreased. In order to investigate the molecular mechanism regulating this effect, the expression of adenosine monophosphate­activated protein kinase (AMPK), activated by 3­BP, was determined. It was demonstrated that phosphorylated­AMPK was upregulated following treatment with 3­BP. Notably, Compound C, an AMPK inhibitor, reversed the effects of 3­BP. Finally, a synergistic antitumor effect of 3­BP and TRAIL was observed in MCF­7 cell xenografts in nude mice. In conclusion, these results indicated that 3­BP sensitized breast cancer cells to TRAIL via the AMPK­mediated upregulation of DR5.

[Small interfering RNA-mediated monocarboxylate transporter 1 silencing enhances sensitivity of nasopharyngeal carcinoma HNE1/DDP cells to cisplatin-induced apoptosis].

OBJECTIVE: To investigate the effect of small interfering RNA (siRNA)-mediated silencing of monocarboxylate transporter 1 (MCT1) on the sensitivity of drug-resistant nasopharyngeal carcinoma HNE1/DDP cells to cisplatin (DDP)-induced apoptosis and explore the possible mechanism. METHODS: The expression of MCT1 was analyzed in HNE1 and HNE1/DDP cells and in HNE1/DDP cells transfected with siRNA using Western blot. MTT assay was used to assess the inhibitory effect of different concentrations of DDP alone or in combination with MCT1 siRNA on the proliferation of HNE1/DDP cells. The apoptosis of cells treated with MCT1 siRNA or/and DDP (8 µmol/L) was assessed using flow cytometry with PI staining, and the mitochondrial membrane potential was detected using JC-1 staining assay; the expressions of Mcl-1, Bak, Bcl-2, and Bax were analyzed using Western blotting. RESULTS: HNE1/DDP cells showed a high expression of MCT1, and MCT1 silencing using siRNA significantly increased the sensitivity of HNE1/DDP cells to DDP (P<0.05) and partly reversed DDP resistance of the cells. MCT1 silencing enhanced the sensitivity of HNE1/DDP cells to DDP-induced apoptosis. Treatment of HNE1/DDP cells with MCT1 siRNA combined with 8 µmol/L DDP for 24 h resulted in an apoptotic rate of (51.23∓2.86)%, significantly higher than that in cells treated with MCT1 siRNA or DDP alone (P<0.05). The combined treatment also reduced the mitochondrial membrane potential, down-regulated the expression of Mcl-1 and Bcl-2, and up-regulated the expression of Bax in the DDP-resistant cells. CONCLUSION: MCT1 siRNA can enhance the sensitivity of HNE1/DDP cells to DDP-induced apoptosis, the mechanism of which may involve the down-regulation of Mcl-1 and Bcl-2 and up-regulation of Bax expression.

Erratum: Analytical Sciences, 2016, Vol. 32, No. 9, p. 969, Chromatographic Fingerprint-Bioactivity Relationships of the Antitumor Properties of Bufo bufo gargarizans Skin Extracts.

On page 969, the author line,    Lulu SUN,* Jing ZHANG,** Surong ZHAO,* Qiong PAN,* Hongmin ZHANG,* Hao LIU,* and Zhitao ZHANG*should read     Lulu SUN,* Jing ZHANG,** Surong ZHAO,* Qiong PAN,* Hongmin ZHANG,* Hao LIU,*† and Zhitao ZHANG*†.On page 969, the sentences,     † To whom correspondence should be addressed.     E-mail: liuhao6886@foxmail.com; 13956336300@126.comshould be added on the footnote.

Chromatographic Fingerprint-Bioactivity Relationships of the Antitumor Properties of Bufo bufo gargarizans Skin Extracts.

Statistical analyses of high-performance liquid chromatography (HPLC)-based chemical fingerprints of Bufo bufo gargarizans toad skin extracts were integrated with antitumor evaluations as a means to more effectively identify bioactive constituents. Specifically, chemical fingerprints of Bufo bufo gargarizans skin extract samples obtained from ten different regions in China were generated by HPLC, and then subjected to similarity analysis and principal component analysis (PCA). Concurrently, a MCF-7 breast cancer cell model was adopted to obtain the antitumor activity of different toad skin extracts. The chromatographic fingerprint-bioactivity relationships of the Bufo bufo gargarizans extracts were then evaluated by Pearson correlation analysis. The results demonstrated that all skin extract samples inhibited the proliferation of MCF-7 cells to some extent, and that there was a correlation between the chemical fingerprints and the anti-proliferative activity. Bufotalin, bufalin, and cinobufagin, three known components of Bufo bufo gargarizans that were identified in the chemical fingerprints, were highlighted as constituents responsible for the observed bioactivity. The activity of cinobufagin was confirmed by cell viability and colony formation assays using MCF-7 cells. The approach documented here provides a more effective means to associate chemical information on medicinal extracts with the principle components responsible for their bioactivity, and to therefore expedite drug discovery.

Hepatotoxicity and nephrotoxicity of 3-bromopyruvate in mice.

PURPOSE:: To investigate the hepatotoxicity and nephrotoxicity of 3-Bromopyruvate (3BP) in mice. METHODS:: Fifteen nude mice were grafted subcutaneously in the left flank with MDA-MB-231 cells, then all mice were divided into control group (PBS), 3BP group (8 mg/kg), positive group (DNR: 0.8 mg/kg) when tumor volume reached approximately 100 mm3. 28 days later, tumors, livers and kidneys were stored in 4 % formalin solution and stained with hematoxylin and eosin staining. The Kunming mice experiment included control group (PBS), 3BP group (4mg/kg; 8mg/kg; 16mg/kg), positive group (DNR: 0.8 mg/kg). 24 hours later, the blood were used for the determination of hepatic damage serum biomarkers. Livers were stored in 4 % formalin solution for the later detection. RESULTS:: 3BP at the dose of 8mg/kg had a good effect on inhibiting tumor growth in nude mice and did not damage liver and kidney tissues. Kunming mice experiment showed 3BP at the dose of 16mg/kg did damage to liver tissues. CONCLUSION:: 3-Bromopyruvate at the dose of suppressing tumor growth did not exhibit hepatotoxicity and nephrotoxicity in nude mice, and the effect on liver was confirmed in Kunming mice.

MicroRNA-10b regulates epithelial-mesenchymal transition by modulating KLF4/Notch1/E-cadherin in cisplatin-resistant nasopharyngeal carcinoma cells.

Epithelial-mesenchymal transition (EMT) is an initiating event in tumor cell invasion and metastasis that contributes to therapeutic resistance to compounds including cisplatin. MicroRNAs (miRNAs) have been associated with EMT as well as resistance to standard therapies. However, the underlying mechanisms by which miRNAs control the development of resistance to cisplatin (DDP), and the accompanying EMT-like properties are required to elucidate. Here we show that microRNA-10b (miR-10b) is up-regulated in HNE1/DDP cells, and inhibition of miR-10b expression reversed the EMT phenotype. However, over-expression of miR-10b was able to promote the acquisition of an EMT phenotype in HNE1 cells. Additionally, we identified that miR-10b expression inversely correlates with KLF4, which then controls expression of Notch1. Knock-down of Notch1 inhibited cell migration, invasion, and reversed EMT in HNE1/DDP cells, which was dependent on miR-10b. In summary, our results reveal that miR-10b regulates EMT by modulating KLF4/Notch1/E-cadherin expression, which promotes invasion and migration of nasal pharyngeal carcinoma cells.

Inhibitory effects of 3-bromopyruvate in human nasopharyngeal carcinoma cells.

Tumor cells depend on aerobic glycolysis for adenosine triphosphate (ATP) production, which is therefore targeted by therapeutic agents. The compound 3-bromopyruvate (3-BrPA), a strong alkylating agent and hexokinase inhibitor, inhibits tumor cell glycolysis and the production of ATP, causing apoptosis. 3-BrPA induces apoptosis of nasopharyngeal carcinoma (NPC) cell lines HNE1 and CNE-2Z, which may be related to its molecular mechanisms. In the present study, we investigated the effects of 3-BrPA on the viability, reactive oxygen species (ROS), apoptosis and other types of programmed cell death in NPC cells in vitro and in vivo. PI staining showed significant apoptosis in NPC cells accompanied by the overproduction of ROS and downregulation of mitochondrial membrane potential (MMP, ΔΨm) by 3-BrPA. However, the ROS scavenger N-acetyl-L-cysteine (NAC) significantly reduced 3-BrPA-induced apoptosis by decreasing ROS and facilitating the recovery of MMP. We elucidated the molecular mechanisms underlying 3-BrPA activity and found that it caused mitochondrial dysfunction and ROS production, leading to necroptosis of NPC cells. We investigated the effects of the caspase inhibitor z-VAD-fmk, which inhibits apoptosis but promotes death domain receptor (DR)-induced NPC cell necrosis. Necrostatin-1 (Nec-1) inhibits necroptosis, apparently via a DR signaling pathway and thus abrogates the effects of z-VAD­fmk. In addition, we demonstrated the effective attenuation of 3-BrPA-induced necrotic cell death by Nec-1. Finally, animal studies proved that 3-BrPA exhibited significant antitumor activity in nude mice. The present study is the first demonstration of 3-BrPA-induced non-apoptotic necroptosis and ROS generation in NPC cells and provides potential strategies for developing agents against apoptosis­resistant cancers.