OBJECTIVETo observe the influence of Cx26/Cx32 gap junction channel on the antineoplastic effect of etoposide in Hela cervical cancer cells.

METHODSFluorescence trace was used to assay the gap junction intercellular communication mediated by Cx26/Cx32 in Hela cells and its functional modulation by the pharmacological agents (oleamide, retinoid acid). A standard colony-forming assay was applied to determine the cell growth-inhibiting effect of etoposide in Hela cells with functional modulation of the gap junction. Hoechst 33258 staining was used to assess the changes in etoposide-induced apoptosis of Hela cells with altered gap junction functions.

RESULTSOleamide markedly decreased while retinoid acid obviously increased the gap junction function in Hela cells. Standard colony-forming assay showed that etoposide produced a lowered antiproliferative effect in Hela cells with reduced gap junction and an increased antiproliferative effect in cells with enhanced gap junction function. In cells with a reduced gap junction function, etoposide induced a lowered apoptosis rate, which increased obviously in cells with an enhanced gap junction function.

CONCLUSIONThe antineoplastic effect of etoposide is reduced in Hela cells with a decreased gap junction intercellular communication mediated by Cx26/Cx32 and is enhanced in cells with an increased gap junction intercellular communication.

Antineoplastic Agents, Phytogenic ; pharmacology ; Connexin 26 ; Connexins ; genetics ; metabolism ; physiology ; Etoposide ; pharmacology ; Gap Junctions ; physiology ; HeLa Cells ; Humans ; Transfection

This study investigated the effect of etoposide, an anticancer chemotherapy drug, on B7-H1 expression in retinoblastoma (Rb) cells and the role of miR-513a-5p in the process. Rb cells were divided into control and etoposide groups. In the etoposide group, cells were treated with etoposide at different concentrations (2.5, 5, 10, 20 and 40 μg/mL) for 24 h. Those given no treatment of etopside served as controls. Reverse transcription polymerase chain reaction (RT-PCR), fluorescence quantitative PCR and flow cytometry were performed to measure the mRNA and protein expression of B7-H1 in Rb cells. The mRNA expression of miR-513a-5p in Rb cells before and after etoposide treatment was also detected by fluorescence quantitative PCR. The miR-513a-5p mimics and the miR-513a-5p inhibitor were transfected into Rb cells separately, and fluorescence quantitative PCR and flow cytometry were used to detect the effect of the miR-513a-5p mimics or inhibitor on B7-H1 expression. TargetScan5.2 was employed to predict the miR-513a-5p binding sites in the 3'-untranslated region of B7-H1 mRNA. Luciferase reporter plasmids carrying this site were prepared and transfected into Rb cells and luciferase activity analyzed. The results showed that etoposide stimulated the mRNA and protein expression of B7-H1 in Rb cells, which reached a maximal level after treatment with 5 μg/mL etoposide (P<0.05). However, miR-513a-5p expression was decreased in Rb cells after etoposide treatment. When the miR-513a-5p inhibitor was added, B7-H1 expression was increased with the concentration of the miR-513a-5p inhibitor (P<0.05). Moreover, B7-H1 expression was decreased gradually with the concentration of the miR-513a-5p mimics increased (P<0.01). Additionally, the miR-513a-5p mimics were found to inhibit the luciferase activity. It was concluded that etoposide can promote B7-H1 expression in Rb cells, which may be associated with chemoresistance. The promoting effect of etoposide on B7-H1 expression can be reversed by miR-513a-5p mimics. MiR-513a-5p inhibits the mRNA and protein expression of B7-H1 via binding to the 3'-UTR of B7-H1 mRNA.
B7-H1 Antigen ; genetics ; Cell Line, Tumor ; Etoposide ; pharmacology ; Gene Expression ; drug effects ; genetics ; Humans ; MicroRNAs ; genetics ; Retinoblastoma ; genetics

Extracellular matrix (ECM) has been implicated in tumor progress and chemosensitivity. Ovarian cancer brings a great threat to the health of women with a significant feature of high mortality and poor prognosis. However, the potential significance of matrix stiffness in the pattern of long non-coding RNAs (lncRNAs) expression and ovarian cancer drug sensitivity is still largely unkown. Here, based on RNA-seq data of ovarian cancer cell cultured on substrates with different stiffness, we found that a great amount of lncRNAs were upregulated in stiff group, whereas SNHG8 was significantly downregulated, which was further verified in ovarian cancer cells cultured on polydimethylsiloxane (PDMS) hydrogel. Knockdown of SNHG8 led to an impaired efficiency of homologous repair, and decreased cellular sensitivity to both etoposide and cisplatin. Meanwhile, the results of the GEPIA analysis indicated that the expression of SNHG8 was significantly decreased in ovarian cancer tissues, which was negatively correlated with the overall survival of patients with ovarian cancer. In conclusion, matrix stiffening related lncRNA SNHG8 is closely related to chemosensitivity and prognosis of ovarian cancer, which might be a novel molecular marker for chemotherapy drug instruction and prognosis prediction.
Female ; Humans ; Cisplatin/pharmacology* ; Elasticity/physiology* ; Etoposide ; Extracellular Matrix/physiology* ; Ovarian Neoplasms/metabolism* ; RNA, Long Noncoding/metabolism*

OBJECTIVETo investigate the effects of arsenic trioxide (As(2)O(3)) on the apoptosis and P-glyco-protein (P-gp) expression of multidrug-resistant human leukemia K562/ADM cells, and the combined effects of As(2)O(3) with conventional chemotherapeutic agents.

METHODSMultidrug-resistant human leukemia cell line K562/ADM that overexpresses mdr-1 gene was used as the target cells. The cell proliferating activity was assessed with a MTT assay. Cell morphology was examined by light microscopy, confocal microscopy and electron-microscopy. P-gp expression, cell-cycle status were determined by flow cytometry.

RESULTSK562/ADM cells were highly resistant to adriamycin, and cross-resistant to daunorubicin and etoposide. As(2)O(3) at concentrations of 0.5 to 20 micromol/L inhibited the proliferation of K562/ADM cells, and K562/ADM cells were more sensitive to As(2)O(3) than their parent K562 cells did. As(2)O(3) induced marked apoptosis of K562/ADM cells showed by typical apoptotic morphological changes and the appearance of high sub-G(1) cell population. As(2)O(3) significantly inhibited the P-gp expression in K562/ADM cells, and exerted a synergistic effect on the enhancement of the cell sensitivity to adriamycin, daunorubicin and etoposide.

CONCLUSIONAs(2)O(3) induces growth-inhibition and apoptosis of multidrug-resistant K562/ADM cells, and augments synergistically the sensitivity of the cells to conventional chemotherapeutic agents via down-regulation of P-gp expression.

ATP-Binding Cassette, Sub-Family B, Member 1 ; biosynthesis ; drug effects ; Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Daunorubicin ; pharmacology ; Doxorubicin ; pharmacology ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Drug Synergism ; Etoposide ; pharmacology ; Humans ; K562 Cells ; Oxides ; pharmacology

To study the effects of S-2-(3-aminopropylamino) ethyl phosphorothioic acid (WR-2721, amifostine) on proliferation inhibition and apoptosis of HL-60 human leukemia cell line, the cell apoptosis rate of HL-60 was determined by annexin V/PI double staining method. Cell proliferation and chemotherapy sensitivity were analyzed with XTT assay, and the changes of cell cycle were observed through flow cytometry. The results showed that WR-2721 could significantly inhibit HL-60 cell proliferation. After treatment (30 min, 37 degrees C) with WR-2721, the sensitivity of HL-60 cells to VP16 was enhanced, and the IC(50) descended from 52.5 micro g/ml to 40.5 microg/ml. After 72 hours treatment of HL-60 cells with WR-2721, the early apoptotic cells (annexin V-FITC positive/PI negative) were increased from (5.5 +/- 1.9)% to (48.5 +/- 8.4)% (P < 0.001), late apoptotic cells (annexin V-FITC positive/PI positive) were increased from (1.2 +/- 0.5)% to (39.0 +/- 4.0)% (P < 0.001), and HL-60 cells were arrested in G(2)-M phase. In conclusion, WR-2721 treatment can enhance HL-60 cell chemotherapy sensitivity to VP16, inhibit proliferation, induce apoptosis and accumulation of cells in G(2)-M phase.
Amifostine ; pharmacology ; Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Drug Synergism ; Etoposide ; pharmacology ; HL-60 Cells ; Humans

This study was aimed to investigate expression of vascular endothelial growth factor mRNA (VEGF mRNA) and its relationship with leukemic cell apoptosis after VEGF antisense oligonucleotide (VEGF ASODN) transferred into HL-60 cells. The phosphorothiate VEGF ODN was transferred into HL-60 cells in vitro by using cation poly mediated method, the inhibitory rate of cell proliferation was assayed by MTT, expression of VEGF mRNA was measured by RT-PCR, cell apoptosis was detected by cell morphology observation, DNA agarose gel electrophoresis and flow cytometer (FCM). The results showed that difference of the inhibitory rate of cell proliferation and the relative expression of VEGF mRNA between ASODN group and MSODN or control groups under the same condition (p < 0.05) was statistic significant, but no significant difference (p > 0.05) was found between MSODN and control. The number of clusters of cells in ASODN group decreased; the morphology features of apoptotic cells involved cell shrinking, more granulation in cytoplasm, nuclear contracting and many fragments of cells. In MSODN and control groups, however, cells were plump and clear, and grow healthly. The result of electrophoresis revealed DNA ladder in ASODN group, while only one band of DNA in control groups. The rate of cell apoptosis was 19.46% in ASODN group with a significant difference as compared with MSODN groups and control (p < 0.05). The rate of HL-60 cell apoptosis in combination of VEGF ASODN with VP16 was significantly higher than that in VP16 alone (p < 0.05) and showed time- and dose- dependence. It is concluded that VEGF ASODN can down-regulate expression of VEGF mRNA of HL-60 cells, induces the apoptosis, inhibits the proliferation of HL-60 cells and enhances VP16-induced apoptosis in HL-60 cells, the VEGF ASODN in combination with VP16 shows additive effect.
Apoptosis ; drug effects ; Cell Proliferation ; drug effects ; Etoposide ; pharmacology ; HL-60 Cells ; Humans ; Oligonucleotides, Antisense ; pharmacology ; RNA, Messenger ; metabolism ; Transfection ; Vascular Endothelial Growth Factor A ; metabolism

The expression levels of programmed cell death 5 (PDCD5) are down-regulated in many malignancies. SG611-pdcd5, a recombinant conditionally replicative adenovirus carrying pdcd5 gene expression cassette, can evidently kill the leukemic cells and protect selectively the normal cells. The purpose of this study was to investigate the synergistic killing effect of SG611-pdcd5 and low-dose etoposide (VP-16) on K562 cells. K562 cells were treated with different concentrations of VP-16 or different multiplicities of infection (MOI) of SG611-pdcd5. After 48 hours of incubation the cell viability was determined by using MTT assay. The results showed that the cell viability of SG611-pdcd5 (MOI = 40) plus VP-16 (0.5 µg/ml) group significantly decreased as compared with single SG611-pdcd5 (MOI = 40) treatment group or single VP-16(0.5 µg/ml) treatment group (42.00 ± 5.75% vs 59.45 ± 4.12%; 42.00 ± 5.75% vs 82.91 ± 3.41%, respectively, both p < 0.05). The synergistic killing effect of SG611-pdcd5 plus VP-16 was higher than that of PDCD5 protein plus VP-16 or that of non-replicating adenovirus carrying pdcd5 (Ad-pdcd5) plus VP-16 (both p < 0.05). The cell viability of VP-16 (4.0 µg/ml) plus SG611-pdcd5 (MOI = 40) group, VP-16 (4.0 µg/ml) plus proPDCD5 (40 µg/ml) group and VP-16 (4.0 µg/ml) plus Ad-pdcd5 (MOI = 80) group was 37.09 ± 1.89%, 52.36 ± 1.64% and 73.64 ± 4.33%, respectively. It is concluded that SG611-pdcd5 can promote K562 cell death induced by low-dose VP-16. The combination of SG611-pdcd5 and VP-16 can enhance the killing effect on leukemic cells.
Adenoviridae ; genetics ; Antineoplastic Agents, Phytogenic ; pharmacology ; Apoptosis ; Apoptosis Regulatory Proteins ; genetics ; Cell Survival ; Etoposide ; pharmacology ; Genetic Vectors ; Humans ; K562 Cells ; Neoplasm Proteins ; genetics

More than 95% of the thyroid carcinomas are well differentiated types showing favorable prognosis. However, only a few therapeutic options are available to treat the patients with undifferentiated thyroid carcinomas, especially with refractory thyroid carcinomas that are not amenable to surgery or radioiodine ablation. We investigated the anticancer effects of 20 chemotherapy and hormonal therapy drugs on 8 thyroid carcinoma cell lines. In vitro chemosensitivity was tested using the adenosine-triphosphate-based chemotherapy response assay (ATP-CRA). The tumor inhibition rate (TIR; or cell death rate) or half maximal inhibitory concentration (IC50) was analyzed to interpret the results. Of the 12 chemotherapy drugs, etoposide (178.9 index value in follicular carcinoma cell line) and vincristine (211.7 in Hurthle cell carcinoma cell line) were the most active drugs showing the highest chemosensitivity, and of the 8 additional drugs, trichostatin A (0.03 microg/mL IC50 in follicular carcinoma cell line) showed favorable outcome having the anticancer effect. In our study, the result of etoposide and vincristine show evidence as active anticancer drugs in thyroid carcinoma cell lines and trichostatin A seems be the next promising drug. These drugs may become an innovative therapy for refractory thyroid carcinomas in near future.
Adenosine Triphosphate/chemistry/pharmacology/therapeutic use ; Antineoplastic Agents/chemistry/*pharmacology/therapeutic use ; Apoptosis/drug effects ; Cell Line, Tumor ; Etoposide/chemistry/pharmacology/therapeutic use ; Humans ; Hydroxamic Acids/chemistry/pharmacology/therapeutic use ; Thyroid Neoplasms/drug therapy ; Vincristine/chemistry/pharmacology/therapeutic use

Caspases play important roles in cell apoptosis. Measurement of the dynamics of caspase activation in tumor cells not only facilitates understanding of the molecular mechanisms of apoptosis but also contributes to the development, screening, and evaluation of anticancer drugs that target apoptotic pathways. The fluorescence resonance energy transfer (FRET) technique provides a valuable approach for defining the dynamics of apoptosis with high spatio-temporal resolution. However, FRET generally functions in the single-cell level and becomes ineffective when applied in the high throughput detection of caspase activation. In the current study, a FRET sensor was combined with capillary electrophoresis (CE) to achieve a high throughput method for cellular caspase detection. The FRET-based CE system is composed of a homemade CE system and a laser source for detecting the dynamics of caspase-3 in various cells expressing sensors of caspase-3 that have been treated with anticancer drugs, such as cell cycle-independent drug cisplatin and specific cell cycle drugs camptothecin and etoposide, as well as their combination with tumor necrosis factor (TNF). A positive correlation between the caspase-3 activation velocity and drug concentration was observed when the cells were treated with cisplatin, but cells induced by camptothecin and etoposide did not show any apparent correlation with their concentrations. Moreover, different types of cells presented distinct sensitivities under the same drug treatment, and the combination treatment of TNF and anticancer drugs significantly accelerated the caspase-3 activation process. Its high throughput capability and detection sensitivity make the FRET-based CE system a useful tool for investigating the mechanisms of anticancer drugs and anticancer drug screening.
Antineoplastic Agents ; pharmacology ; Camptothecin ; pharmacology ; Caspase 3 ; metabolism ; Cisplatin ; pharmacology ; Drug Screening Assays, Antitumor ; Electrophoresis, Capillary ; methods ; Enzyme Activation ; drug effects ; Etoposide ; pharmacology ; HeLa Cells ; Hep G2 Cells ; Humans ; Neoplasms ; enzymology ; pathology ; Time Factors ; Tumor Necrosis Factor-alpha ; pharmacology

OBJECTIVETo study the effects of two specific cyclooxygenase inhibitors (SCI), rofecoxib and celecoxib, combined with chemotherapeutic drugs 5-Fu, DDP and VP-16 on gastric cancer cell line BGC-823, and to evaluate whether specific cyclooxygenase inhibitors can be used as a synergetic agent in chemotherapy.

METHODSThe gastric cancer cell line BGC-823 cells were incubated for 48 hours with rofecoxib and celecoxib, 5-Fu, DDP and VP-16 (concentration gradient of 5-Fu, DDP and VP-16:1 microg/ml, 10 microg/ml and 100 microg/ml), or in combination, respectively. MTT working solution was added to each culture and calculated the survival rates of gastric cancer cells. Median-effect principle and Professor Jin's evaluation methods were applied to detect the interaction between the specific cyclooxygenase inhibitors and chemotherapeutic agents.

RESULTSThe inhibition rates of gastric cancer cells were 42.63% +/- 1.26% and 50.67% +/- 2.35% by treatment with 0.1 micromol/L rofecoxib and 50 micromol/L celecoxib, respectively. The inhibition rates of gastric cancer cells by treatment with 5-Fu, DDP and VP-16 at different concentrations (1 microg/ml, 10 microg/ml and 100 microg/ml) were 39.75% +/- 3.14%, 49.96% +/- 2.08%, 87.93% +/- 3.66%; 48.28% +/- 2.08%, 59.46% +/- 1.69%, 88.23% +/- 4.81%; and 29.23% +/- 3.27%, 49.34% +/- 3.75%, 79.24% +/- 2.44%, respectively. However, the inhibition rates showed a synergetic role while combined the two SCI (0.1 micromol/L rofecoxib and 50 micromol/L celecoxib) with chemotherapeutic agent at different concentrations (P <0.05).

CONCLUSIONBoth rofecoxib and celecoxib have an ability to suppress gastric cancer cells in vitro, and the synergetic role becomes evident when rofecoxib and celecoxib are combined with chemotherapeutic agents at different concentrations, which indicate that the two specific cyclooxygenase inhibitors may be used as a chemotherapeutic sensitizer.

Adenocarcinoma ; pathology ; Antimetabolites, Antineoplastic ; pharmacology ; Antineoplastic Agents ; pharmacology ; Celecoxib ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Cisplatin ; pharmacology ; Cyclooxygenase 2 Inhibitors ; pharmacology ; Cyclooxygenase Inhibitors ; pharmacology ; Dose-Response Relationship, Drug ; Drug Synergism ; Etoposide ; pharmacology ; Fluorouracil ; pharmacology ; Humans ; Lactones ; pharmacology ; Pyrazoles ; pharmacology ; Stomach Neoplasms ; pathology ; Sulfonamides ; pharmacology ; Sulfones ; pharmacology