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Objective To investigate the effect of the SMAC gene on paclitaxel sensitivity and cellular activity in lung adenocarcinoma cells based on the caspase-3/Bcl-2/Bax signaling pathway. Methods A paclitaxel-resistant cell line A549/Taxol was established for lung adenocarcinoma, and the cells were divided into four following groups: pcDNA-NC (transfected with pcDNA-NC blank vector), pcDNA-SMAC (transfected with pcDNA-SMAC vector), siRNA-NC (transfected with siRNA-NC empty virus vector), and siRNA-SMAC groups (transfected with siRNA-SMAC lentiviral vector). The SMAC mRNA expression in cells was detected by qRT-PCR; cell sensitivity was detected by MTT; cell proliferation ability was detected by cloning assay; cell invasion ability was detected by Transwell; apoptosis ability was detected by flow cytometry assay; and caspase-3, Bcl-2 and Bax protein expression in cells were detected by Western blot analysis. Results The SMAC mRNA expression was significantly lower in A549 cells compared with BEAS-2B cells (P < 0.05). The SMAC mRNA expression was significantly higher in the pcDNA-SMAC group than that in the pcDNA-NC group cells (P < 0.05). The SMAC mRNA expression was significantly lower in the cells of the siRNA-SMAC group (P < 0.05) than that in the siRNA-NC group. The SMAC mRNA expression was significantly lower in the cells of the siRNA-SMAC group (P < 0.05) than in the siRNA-NC group. Compared with the pcDNA-NC group, the cell IC50, cell clone number, cell invasion ability, and Bcl-2 protein and Bcl-2/Bax ratio were significantly lower in the pcDNA-SMAC group, the cell resistance index reversal was 2.51-fold, and the apoptosis ability and caspase-3, as well as Bax protein expression, were significantly higher (P < 0.05). Compared with the siRNA-NC group, cell IC50, cell clone number, cell invasion ability, and Bcl-2 protein and Bcl-2/Bax ratio were significantly higher in the siRNA-SMAC group, and apoptosis ability and caspase-3 and Bax protein expression were significantly lower (P < 0.05). Conclusion High expression of SMAC increases paclitaxel sensitivity, inhibits cell growth and invasion, promotes apoptosis in lung adenocarcinoma cells, and has a regulatory effect on the caspase-3/Bcl-2/Bax signaling pathway.
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Objective:To explore the potential targets and related mechanism involved in the paclitaxel resistance to ovarian cancer. Method:Ovarian cancer A2780 cells and A2780 paclitaxel-resistant cells （A2780/T） were treated by 2， 4， 8， 16， 32， 64， 128， 256 μmol·L<sup>-1</sup> paclitaxel （PTX） for 24 h or 48 h respectively <italic>in vitro</italic>. The proliferation rate of A2780 cells and A2780/T cells treated with paclitaxel was determined by methyl thiazolyl tetrazolium （MTT） colorimetric method assay. A2780 and A2780/T cells were analyzed by LC-MS/MS Label-Free quantitative proteomics to identify and screen differentially expressed proteins in the two groups of cells. Gene ontology （GO） annotation and Kyoto encyclopedia of genes and genomes （KEGG） pathway analysis were used to determine the potential biomarkers of paclitaxel resistance in ovarian cancer. Conventionally cultured A2780 cells were used as a control group， and A2780/T cells were treated with 0， 1， 4 μmol·L<sup>-1</sup> PTX. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot methods were used to detect and verify the mRNA and protein expression levels of potential target transforming growth factor-<italic>β</italic>-activated kinase 1 binding protein 1 （TAB1） and its downstream related molecules transforming growth factor-<italic>β</italic>-activated kinase （TAK1） and p38. Result:After PTX treatment for 24 h and 48 h， the cell viability of A2780 and A2780/T cells decreased. The inhibitory rate of PTX on A2780 cells was significantly higher than that of A2780/T cells. In A2780 cells， the IC<sub>50</sub> of PTX treatment for 48 h was 0.002 μmol·L<sup>-1</sup>， while in A2780/T cells， the IC<sub>50 </sub>of PTX was greater than the maximum concentration of 128 μmol·L<sup>-1</sup>， indicating that A2780/T cells were resistant to PTX compared with A2780 cells. 441 differentially expressed proteins and 421 special differentially expressed proteins between A2780/T and A2780 cells were screened by label-free quantitative proteomic analysis. GO function enrichment analysis showed that the binding proteins accounted for the majority （80%） among the differentially expressed proteins. According to the results of KEGG pathway analysis and expression site analysis， TAB1 might be a potential biomarker in paclitaxel-resistant ovarian cancer. Compared with A2780 cells， mRNA and protein expression levels of TAB1 in A2780/T cells were significantly reduced （<italic>P</italic><0.01）. mRNA expression of TAK1 and p38 that interacted with TAB1 were also significantly reduced （<italic>P</italic><0.05， <italic>P</italic><0.01）， while there was no significant change in protein expression. Conclusion:TAB1 may be a potential biomarker of paclitaxel resistance to ovarian cancer ， and its mechanism may be related to the TAB1/TAK1/p38 MAPK pathway.
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OBJECTIVE：To struc turally modify shikimic acid ，and to investigate the reversal effects of its derivatives on paclitaxel-resistant human breast cancer cells MCF- 7/PTX. METHODS ：Using shikimic acid as the lead structure ，1-position carboxyl group was structurally modified to synthesize a series of shikimic acid derivatives through esterification ，amidation， hydrogenation and reduction ，etc. Using non-drug resistant cells MCF- 7 as reference ，MTT assay was used to screen derivatives with inhibitory activity as well as half-inhibitory concentration （IC50）and reversal index （RI）of derivatives to MCF- 7/PTX. With the drug resistance-related transgelin 2 as the target ，the molecular docking of the active derivatives with the drug resistance-related protein was carried out by using Glide 1.0 computer-aided design software. RESULTS ：Totally 15 derivatives were obtained （T1-T15）， of which T 4-T15 were obtained for the first time. MTT assay showed that （3R， 4S， 5R） -N-benzyl-3， 4， 5-trihydroxy-1-cyclohexene-1-formamide（T7），（3R，4S，5R）-N-（3，4，5-trihydroxy-1-cyclohexenylmethyl）-benzylamine（T14）， （3R，4S，5R）-3，4-O-isopropyl-5-O-acetyl-1-cyclohexene-1-methyl formate （T15）inhibited MCF- 7 and MCF- 7/PTX cells to a certain extent ；IC50 values of T 7，T14 and T 15 combined with pacliaxel to MCF- 7/PTX cells were significantly lower than that in negative control （Paclitaxel alone ）group（P＜0.05）. RIs of T 14 and T 15 were higher ，and RIs of the highest dose were 8.8 and 9.3， which were equivalent to positive control verapamil （10.8）. Th e results of molecular docking showed that the hydroxyl groups at positions 3，4 of T 7 could form multiple hydrogen bonds with ； Arg625 and Asp 627 in the catalytic region of transgelin 2. In addition to the hydrogen bond mentioned above at T 7，the mail：batistuta28@126.com secondary amine side chain at position 1 of T 14 could also form hydrogen bond with Glu 657 of transgelin 2. When the hydroxyl group on the T 15 mother nucleus was derived from the donor group ，the binding of the hydroxyl group to transgelin 2 was closer and the inhibition was enhanced. CONCLUSIONS ： The derivatives T 7，T14 and T 15 have certain reverse activity to paclitaxel-resistant human breast cancer cells. The polyhydroxy structure of the mother nucleus is the main structural region of the hydrogen bond between shikimic acid and its derivatives and transgelin 2. The derivation of its power supply group or the introduction of secondary amines and hydrophobic groups into the 1-carboxyl group of shikimic acid is benifit for enhancing the drug resistance reversal effect of derivative .
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OBJECTIVE@#To investigate the role of long-chain non-coding RNA MALAT1 in modulating paclitaxel resistance in breast cancer cells.@*METHODS@#Breast cancer SK-BR-3 cells were treated with gradient concentrations of paclitaxel to induce paclitaxel resistance of the cells. The resistant cells were transfected with si-NC, si-MALAT1, pcDNA, pcDNA-MALAT1, miRNC, miR-485-3p mimics, si-MALAT1+anti-miR-NC, or si-MALAT1+anti-miR-485-3p liposomes. Following the transfections, the cells were examined for changes in IC of paclitaxel using MTT assay; the protein expression of P-gp, Bcl-2 and Bax were detected with Western blotting, and a dual luciferase reporter assay was used to detect the binding of MALAT1 to miR-485-3p.@*RESULTS@#Compared with paclitaxel-sensitive SK-BR-3 cells, paclitaxel-resistant SK-BR-3 cells showed significantly increased the IC of paclitaxel with up-regulated MALAT1 expression and down-regulated miR-485-3p expression ( < 0.05). Silencing MALAT1 or overexpressing miR-485-3p obviously lowered the IC of paclitaxel and the expression of P-gp and Bcl-2 and increased the expression of Bax in SK-BR-3/PR cells ( < 0.05). miR-485-3p was identified as the target of MALAT1, and inhibiting miR-485-3p significantly reverse the effect of MALAT1 silencing on IC of paclitaxel and the expressions of P-gp, Bcl-2 and Bax in SK-BR-3/PR cells ( < 0.05).@*CONCLUSIONS@#MALAT1 can modulate paclitaxel resistance in breast cancer cells possibly by targeting miR-485-3p to down-regulate P-gp and Bcl-2 and up-regulate Bax.
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Humans , Cell Line, Tumor , MicroRNAs , Paclitaxel , RNA, Long Noncoding , GeneticsABSTRACT
Objective To establish the paclitaxel-resistant gastric cancer cell(HGC-27/PTX) and to investigate the changes of characteristics before and after resistance,as well as the possible resistant mechanisms.Methods The paclitaxel-resistant gastric cancer cell HGC-27/PTX was established by increasing paclitaxel dose gradually and intermittently.The IC50 (50% inhibitory concentration) and cell cycle were determined by CCK-8 assay and flow cytometry,respectively.The differentially expressed genes (DEGs) and signaling pathways were analyzed using RNAseq.Results The establishment of HGC-27/PTX cells lasted 9 months,and the sensitivity of paclitaxel of HGC-27/PTX cells was significantly lower than parental cells (P<0.05).Compared to parental cells,the morphology of HGC-27/PTX cells was slightly different,and the proportion of S and G2/M phase was obviously increased (P<0.01).A total of 274 DEGs were identified between the resistant and parental cells with 130 genes up-regulated and 144 genes down-regulated.DEGs were significantly enriched in extracellular matrix (ECM)-receptor interaction(P<0.001) and PI3K-Akt signaling pathways (P<0.05),which could provide evidences for reversing paclitaxel resistance.Conclusions The paclitaxel-resistant gastric cancer cells HGC-27/PTX was established with stable culturein vitro,which provides an ideal model for future study on the mechanism of drug resistance.
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OBJECTIVE: To investigate the effect of transgelin 2 on paclitaxel resistance, migration and invasion in MCF-7/PTX cells. METHODS: The morphology of MCF-7/S and MCF-7/PTX cells was observed under light microscope. Cell viability was determined using MTT method. The protein and mRNA expressions of transgelin 2, EMT markers including E-cadherin, N-cadherin and Vi-mentin in breast cancer cells were detected by Western blot assay and real-time PCR assay. Wound healing scratch assay and transwell invasion assay were performed to analyze migratory and invasive capability of cells, respectively. Transgelin 2 was reduced in MCF-7/PTX cells by transfecting with TAGLN2 small interference RNA (siRNA). RESULTS: EMT process existed in MCF-7/PTX cells and these cells achieved a high degree of resistance to paclitaxel, and possessed strong ability of migration and invasion. TAGLN2 siRNA treatment sensitized the MCF-7/PTX cells to paclitaxel, and inhibited migration and invasion. CONCLUSION: Overexpression of transgelin 2 could not only induce the paclitaxel resistance, but also inhibit migration and invasion in MCF-7/PTX cells, suggesting that transgelin 2 may serve as a novel biomarker and therapeutic target for breast cancer.
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OBJECTIVE: To investigate the resistance mechanisms related to SET in paclitaxel-induced human breast cancer cells. METHODS: The different expressions of SET and ABC transporters between MCF-7/S and paclitaxel resistant MCF-7/PTX cells were identified using Western blot. We adopted siRNA method to knockdown SET in MCF-7/PTX cells and plasmid transfection analysis to up-regulated SET in MCF-7/S cells. The cell viability to paclitaxel was assessed by MTT assay. The cell apoptosis was analyzed by flow cytometry. The levels of ABC transporters were analyzed using Western blot and Real-time PCR, respectively. RESULTS: We found that higher levels of SET and ABC transporters in MCF-7/PTX cells. Knockdown of SET not only significantly sensitized MCF-7/PTX cells to paclitaxel, but also induced cell apoptosis. The levels of the ABC transporters were also reduced. Upregulated SET in MCF-7/S cells expressed resistant to paclitaxel and decreased cell apoptosis. High expression of the SET significantly promotes the mRNA and protein level of ABC transporters. CONCLUSION: The above results demonstrate that SET is associated with paclitaxel resistance in MCF-7/PTX cells. The SET is expected to be one of novel biological targets of overcoming paclitaxel resistant in breast cancer treatment.
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In this article, the status of spindle assembly checkpoint and the alteration of its major component, Mad2 protein level were examined in A2780 and SKOV3 ovarian cancer cell lines. Recombinant eukaryotic expression plasmid pEGFP-Mad2 was transfected into paclitaxel-resistant SKOV3 cells and Mad2 protein was knocked down by Mad2-specific siRNA in paclitaxel-sensitive A2780 cells. Then the expression level of Mad2 gene was detected by Western blotting. Flow cytometry revealed that SKOV3 cells were not fully arrested in G2/M phase in contrast to A2780 cells in the presence of paclitaxel. However, paclitaxel sensitivity assay showed that sensitivity to paclitaxel was reversed after the transfection in both cell lines in terms of number of cells arrested at G2/M phase and the expression of Bcl-2 was significantly changed. These results suggest that weakened spindle checkpoint with reduced expression of Mad2 is associated with resistance to paclitaxel in ovarian cells and Bcl-2 may be involved in this process.
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To investigate the relationship between the expression of early growth response gene 1(EGR-1) and p38MAPK pathway in the paclitaxel resistance of ovarian carcinoma cells, the effect of p38MAPK inhibitor SB203580 on cell apoptosis was examined by using Hoechst 33258 staining.The intracellular Rh123 (Rhodamine 123) accumulation was detected by the flow cytometry (FCM).The 50% inhibition concentration (IC50) of paclitaxel for A2780/Taxol cells was determined by MTT method. Electrophoretic motility shift assay (EMSA) was employed to examine the EGR-1DNA binding activity. MDR1 and EGR-1 mRNA were assessed by RT-PCR. The expressed of p-gp, phosphorylated p53 and p38 were detected by Western blotting. SB203580 could remarkably promote the apoptosis of A2780/Taxol cells, and the cell apoptosis was in a time-dependent manner. Cellular Rh123 accumulation was increased, and the IC50 of paclitaxel for A2780/Taxol cells was decreased significantly. A2780/Taxol cell line after SB203580 treatment was shown to have a significantly higher level of EGR-1 DNA binding activity. SB203580 down-regulated the activity of p38MAPK pathway, but up-regulated EGR-1 expression. SB203580 significantly increased the level of cellular phosphorylated p53 protein, but decreased the p-gp protein level and MDR1 mRNA level in A2780/Taxol cells. There existed a close relationship between p38MAPK pathway and the paclitaxel resistance of ovarian carcinoma cells. The expression of EGR-1 mediated by p38MAPK pathway plays a critical role in paclitaxel resistance of ovarian carcinoma cells.
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OBJECTIVE: To evaluate the inhibition of Clusterin gene expression via shRNA decreases proliferation and metastasis and increases chemosensitivity to paclitaxel in xenografted PEOH cells. METHODS: 1 x 10(6) paclitaxel resistant cell lines transduced with Clusterin shRNA in lentiviral inoculated subcutaneously into the flank region of 6 to 8 week-old female nude mice. Parental cells transduced with LacZ was used as a control. Tumor growth was measured twice every week and calculated by using the formula: length x width x depth x 0.5236. The mice were sacrificed and examined for Clusterin expression on tumor cells and counted the metastasis sites. RESULTS: shRNA for Cluaterin works in vivo and it is the in accord with the in vitro results. Although shRNA for Clusterin group showed decreased tumor growth and proliferation it has not statistical significance. But transfection of Clusterin shRNA on PEOH significantly increased paclitaxel-sensitivity (P<0.05). CONCLUSION: shRNA targeting of the Clusterin gene decreased the ovarian cancer cell's paclitaxel resistance.