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ObjectiveTo investigate the effect of betulinic acid （BA） on apoptosis and autophagy of human colorectal cancer SW620 cells and the regulatory role of phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt）/mammalian target of rapamycin （mTOR） signaling pathway. MethodCell viability was detected by methyl thiazolyl tetrazolium （MTT） colorimetry to determine the optimal administration time and dosage for subsequent experiments. Four groups were designed， including blank group and low-， medium-， and high-dose BA groups. Hematoxylin-eosin （HE） staining was conducted for the observation of SW620 cell morphology， and annexin-V/propidium iodide double staining for the determination of apoptosis rate in SW620 cells. Hoechst33258 staining and MDC staining were used for the observation of apoptosis and autophagy， respectively. Western blotting was employed to determine the protein levels of B-cell lymphoma/leukemia-2（Bcl-2）-associated X protein （Bax）， aspartate proteolytic enzyme-9 （Caspase-9）， activated aspartate proteolytic enzyme-3 （cleaved Caspase-3）， microtubule-associated protein 1 light chain 3 （LC3）， the mammalian homolog of yeast Atg6 （Beclin-1）， p62， phosphorylated PI3K （p-PI3K）， phosphorylated Akt （p-Akt）， and phosphorylated mTOR （p-mTOR） in SW620 cells. ResultBA inhibited the activity of SW620， HT29， and HCT116 cells in a concentration- and time-dependent manner. The cells treated with BA for 48 h had lower viability than those treated for 24 h （P<0.05， P<0.01）. The half maximal inhibitory concentration (IC50） value of BA at the time point of 48 h was also lower than that at the time point of 24 h （P<0.01）， and that for SW620 cells was the minimum. BA induced the apoptosis in a concentration-dependent manner and increased the autophagosomes. Compared with the blank group， BA increased the apoptosis rate （P<0.01）， up-regulated the protein levels of Bax， Caspase-9， cleaved Caspase-3， and LC3 Ⅱ （P<0.05， P<0.01）， and down-regulated the protein levels of p62， p-Akt， p-PI3K， and p-mTOR （P<0.01）. Additionally， medium- and high-dose BA up-regulated the protein level of beclin-1 （P<0.01）. ConclusionBA may inhibit the activity of SW620 cells by hindering the PI3K/Akt/mTOR signaling pathway to induce cell apoptosis and autophagy.
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Objection@#To investigate the effect of miR-32-5p on the radiosensitivity, migration and invasion of colorectal cancer cells and the underlying mechanism.@*Methods@#Human colorectal cancer SW480 cells and normal colonic epithelial NCM460 cells were cultured. The colorectal cancer cells were divided into the non-transfected and transfected groups (transfected with anti-miR-NC, anti-miR-32-5p, pcDNA, pcDNA-TOB1, anti-miR-32-5p+ si-NC and anti-miR-32-5p+ si-TOB1, respectively). The expression of miR-32-5p and TOB1 at the mRNA and protein levels was detected by RT-qPCR and Western blot. The radiosensitivity of the transfected cells was determined by colony formation assay. The migration and invasion ability of the transfected cells were detected by Transwell assay. Whether miR-32-5p targeted TOB1 was validated by dual luciferase reporter gene assay and Western blot.@*Results@#Compared with human colonic epithelial cells, the expression of miR-32-5p was significantly up-regulated, whereas the expression of TOB1 mRNA and protein was remarkably down-regulated in the colon cancer cells (all P<0.05). Compared with the anti-miR-NC, the quantity of cell migration and invasion was significantly decreased (both P<0.05) and the radiosensitivity ratio was 1.801 in the anti-miR-32-5p group. Compared with the pcDNA group, the quantity of cell migration and invasion was significantly decreased (both P<0.05) and the radiosensitivity ratio was 1.764 in the pcDNA-TOB1 group. Dual luciferase reporter gene assay and Western blot confirmed that miR-32-5p negatively regulated the expression of TOB1 protein. Compared with the anti-miR-32-5p+ si-NC group, the quantity of cell migration and invasion was significantly increased (both P<0.05) and the radiosensitivity ratio was 0.591 in the anti-miR-32-5p+ si-TOB1 group.@*Conclusions@#Inhibition of miR-32-5p expression can significantly enhance the radiosensitivity of colorectal cancer cells and suppress cell migration and invasion. The underlying mechanism might be related to the targeted up-regulation of TOB1 expression.
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Objection To investigate the effect of miR-32-5p on the radiosensitivity,migration and invasion of colorectal cancer cells and the underlying mechanism.Methods Human colorectal cancer SW480 cells and normal colonic epithelial NCM460 cells were cultured.The colorectal cancer cells were divided into the non-transfected and transfected groups (transfected with anti-miR-NC,anti-miR-32-5p,pcDNA,pcDNA-TOB1,anti-miR-32-5p+si-NC and anti-miR-32-5p+si-TOB1,respectively).The expression of miR-32-5p and TOB1 at the mRNA and protein levels was detected by RT-qPCR and Western blot.The radiosensitivity of the transfected cells was determined by colony formation assay.The migration and invasion ability of the transfected cells were detected by Transwell assay.Whether miR-32-5p targeted TOB1 was validated by dual luciferase reporter gene assay and Western blot.Results Compared with human colonic epithelial cells,the expression of miR-32-5p was significantly up-regulated,whereas the expression of TOB1 mRNA and protein was remarkably down-regulated in the colon cancer cells (all P＜0.05).Compared with the anti-miR-NC,the quantity of cell migration and invasion was significantly decreased (both P＜0.05) and the radiosensitivity ratio was 1.801 in the anti-miR-32-5p group.Compared with the pcDNA group,the quantity of cell migration and invasion was significantly decreased (both P＜0.05) and the radiosensitivity ratio was 1.764 in the pcDNA-TOB1 group.Dual luciferase reporter gene assay and Western blot confirmed that miR-32-5p negatively regulated the expression of TOB1 protein.Compared with the anti-miR-32-5p+si-NC group,the quantity of cell migration and invasion was significantly increased (both P＜0.05) and the radiosensitivity ratio was 0.591 in the anti-miR-32-5p+si-TOB1 group.Conclusions Inhibition of miR-32-5p expression can significantly enhance the radiosensitivity of colorectal cancer cells and suppress cell migration and invasion.The underlying mechanism might be related to the targeted up-regulation of TOB1 expression.
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@# Objective: To evaluate whether human NK cells expanded in vitro can be used as carrier cells of reovirus and to investigate its clinical application value. Methods: Expansion of human NK cells in vitro, and flow cytometry was used to analyse the purity of CD3-CD56+ cells. Expanded NK cells were loaded with reovirus and observed by confocal microscopy, to determining the location of reovirus on NK cells. CCK-8 assay was used to detect reovirus-induced oncolysis of expanded NK cells carrying reovirus (Reo-NK) to tumor cells in the presence of neutralizing antibodies; Real-time fluorescence quantitative PCR was used to assess the relative expression of viral RNA in tumor cells. Cytotoxicity assay were performed to detect Reo-NK cells against KRAS mutant (DLD-1) and KRAS wild type (CaCo-2, HT29) colorectal cancer cell lines, ELISA matched paired antibodies assay was performed to measure the perforin level released by NK cells. Results: Confocal microscopy demonstrated that NK cells retained reovirus on the surface. Expanded NK cells could delivery reovirus to tumor cells in the presence of neutralizing antibodies, and the reovirus after delivery still had significant oncolytic activity (P<0.01); Corresponding qPCR result displayed that the expression of viral RNA in tumor cells significantly increased over time (P<0.01). Compared with NK group, Reo-NK group evidently enhanced the cytotoxicity on colorectal cancer cell lines with both KRAS gene mutant and wild (all P<0.05), and significantly increased the release of perforin (all P<0.05). Conclusion: In vitro expanded NK cells provide a convincing cell carrier for reovirus, while reovirus enhances the cytotoxicity of NK cells, and the combination of the two show a stronger killing effect on colorectal cancer cells，that has important clinical application value.
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Objective To investigate the effect of cetuximab (C225) on the radiosensitivity of colorectal cancer cells CL187 and underlying mechanism.Methods Cell survival was detected by colony forming assay.The levels of apoptosis and cell cycle distribution were determined by flow cytometer.The mitotic ratio was measured by Wright' s-Giemsa mixed coloring method.The protein levels of Bax and Bcl2 were detected by Western blot.Results The sensitizing enhancement ratio of C225 was approximately 1.4.C225 treatment and 125I seed radiation induced G1 cell cycle arrest individually.C225 increased the radiation-induced apoptosis (t =6.6,P ＜ 0.05) and cellular Bax/Bcl-2 ratio (t =9.4,P ＜ 0.05),but did not increase radiation-induced G1 arrest.In addition,there was no difference in mitotic index among different groups.Conclusions C225 sensitizes CL187 to 125I seed irradiation,which might be related with increase of radiation-induced apoptosis.
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OBJECTIVE:To investigate the effects of SDZ on LOVO cell line and the expression of E-Cadherin and N-Cadherin. METHODS: The apoptosis of SDZ on growth of LOVO cells was observed under electron microscope and inverted microscope. The expression of E-Cadherin and N-Cadherin treated by SDZ were detected by RT-PCR. RESULTS: SDZ promoted the apoptosis of LOVO cell lines and increased the expression of E-Cadherin,however,it did no effect on the expression of N-Cadherin. CONCLUSION: SDZ can enhance the intercellular adhesiveness and degrade the capability of infiltration and metastasis of tumor cells.
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Objective To explore the effect of hepatocyte growth factor/scatter factor (HGF/SF) on apoptosis of colorectal cancer cells induced with curcumin. Methods MTT assay was used to evaluate the cytotoxicity of curcumin to colorectal cancer cells. Flow cytometry was used to detect the anti-apoptosis effect of HGF. Results Flow cytometry showed only 64 ?g/ml curcumin could play the proliferation-inhibiting role in Caco-2 cells leading to their apoptosis; at the same time, different concentrations of HGF could antagonize this inhibitory effect resulting in the decrease of apoptosis, but HGF worked without a concentration-dependent manner. The study on MAPK pathway showed that the protective effect of HGF on the apoptosis of Caco-2 cells was not influenced by inhibiting p42/p44 MAPK and p38 MAPK pathway. Conclusion HGF/SF antagonizes the apoptosis of Caco-2 cells induced with curcumin, but MAPK signaling pathway might not participate in this process.
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Objective To study the effect of selective cyclooxygenase-2 inhibitor celecoxib on cell apoptosis of human colorectal cancer cell line HT-29 and the probable mechanism involved by detecting the expressions of cytochrome C, Caspase-9 and poly ADP-ribose polymerase(PARP) at protein level. Methods Apoptosis was determined by Acridine orange and Ethidium bromide staining under fluorescence microscope and flow cytometry. The protein expression of cytochrome C, Capsase-9 and PARP were examined by Western blotting.Results Celecoxib induced apoptosis of HT-29 human colorectal cancer cells in a concentration and time-dependent manner from 0 to 120 ?mol/L. Sub-G 1 peak was detected by flowcytometry, and the apoptotic rate was between(7.31?2.37)%-(48.30 ?2.86)%. Celecoxib induced cytochrome C release into the cytosol from mitochondria, then activated Caspase-9 and consequently triggered PARP cleavage.Conclusion Celecoxib can induce apoptosis through a cytochrome C-dependent pathway in human colorectal cancer cell line HT-29.