Effects of curcumin analogue T83 on apoptosis of homologous nasopharyngeal carcinoma cells with different radioresistance

AIM：To compare the effect of T83 (a 4-arylidene curcumin analogue) on the apoptosis of homologous nasopharyngeal carcinoma cells with different radioresistance. METHODS：The effects of T83 on the viability, apoptosis, mitochondrial membrane potential (MMP), expression of procaspase-3/procaspase-9/Cyt-C proteins and relative PTEN/Akt/p27 mRNA expression in CNE-2R cells and CNE-2 cells were detected and compared by the methods of MTT assay, Hoechst staining, flow cytometry, Western blotting and qRT-PCR. RESULTS：T83 inhibited the viability of CNE-2R cells with the IC50 of 0.9,0.4 and 0.2 μmol/L for 24 h, 48 h and 72 h,respectively, which was more effective than that inhibiting the viability of CNE-2 cells with the IC50 of 1.8,0.5 and 0.4 μmol/L, respectively. After treated with T83 for 48 h, chromatin condensation, margination and splitting into a massive structure were observed in CNE-2R cells and CNE-2 cells,and the late apoptotic rate of CNE-2R cells was increased from 1.57% to 27.26%, which was higher than that of CNE-2 cells (1.74% to 8.15%). After treated with T83 for 36 h, the MMP in CNE-2R cells decreased by 87.71% and that decreased by 50.47% in CNE-2 cells. After treated with T83 for 48 h, the protein levels of procaspase-3 and procaspase-9 were decreased, and the protein level of Cyt-C was increased, which were more susceptible in CNE-2R cells than those in CNE-2 cells. After treated with T83 for 24 h, the relative mRNA expression of PTEN and p27 was significantly up-regulated, and the mRNA expression of Akt was down-regulated, which were more susceptible in CNE-2R cells than those in CNE-2 cells. CONCLUSION：Compared with CNE-2 cells, the inhibitory effect of T83 on the viability of CNE-2R cells is more specific by starting the mitochondrial apoptotic pathway, which is due to the inhibition of PTEN/Akt/p27 signaling pathway.     

Effects of curcumin analogue B50 on proliferation and apoptosis of homologous nasopharyngeal carcinoma cells with different radioresistance

AIM: To compare the effects of B50, a mono-carbonyl analogue of curcumin, on the proliferation and apoptosis between homologous nasopharyngeal carcinoma cells CNE-2R and CNE-2 with different radioresistance.METHODS: The effects of B50 on cell viability and cell growth were detected by MTT assay and colony-forming experiment, respectively. The changes of cell cycle, apoptosis and mitochondrial membrane potential (MMP) were determined by flow cytometry.RESULTS: B50 inhibited the cell viability of CNE-2R cells in a time-and dose-dependent manner with the IC₅₀ of (8.06±0.14) μmol/L (24 h), (2.49±0.02)μmol/L (48 h) and (1.42±0.02) μmol/L (72 h), which was more effective than that in CNE-2 cells . The inhibitory effect of B50 on CNE-2R cell growth was more effective than that on CNE-2 cells . After treated with B50 for 48 h, the proportion of CNE-2R cells in G₂/M stage was increased from 7.1% to 34.9%, which was better than that of CNE-2 cells (from 12.4% to 35.7%). After treated with B50 for 24 h, the early apoptotic rate in CNE-2R cells was increased from 3.7% to 19.5%, which was better than that in CNE-2 cells (from 4.4% to 14.8%), and the MMP in CNE-2R cells was decreased by (43.17±3.11)%, which was better than that in CNE-2 cells .CONCLUSION: B50 is more effective on inhibiting the cell viability and cell growth, blocking the cell cycle at G₂/M stage, inducing apoptosis and decreasing MMP in CNE-2R cells than those in CNE-2 cells, indicating that B50 may enhance the radio-sensitivity of CNE-2R cells by blocking the cell cycle and inducing apoptosis through mitochondrial pathway.     

T63 enhances radiotherapeutic sensitivity of nasopharyngeal carcinoma cells through apoptosis and G2/M arrest

AIM: To explore the antitumor effect of a curcumin analogue T63 in human nasopharyngeal carcinoma (NPC) cell lines CNE-2 and CNE-2R. METHODS: Cell viability was monitored by the methods of MTT and colony formation assay. Cell cycle distribution was detected by flow cytometry. Apoptosis was examined using the annexin V-FITC/PI staining assay. RESULTS: A growth inhibitory effect was observed with T63 treatment in a dose-dependent manner. Either T63 or ionizing radiation (IR) significantly induced G2/M arrest and apoptosis in NPC cells. In addition, T63 treatment combined with IR induced significantly higher apoptosis and G2/M arrest in NPC cells. CONCLUSION: T63 exhibits potent inhibitory activity on NPC cells and induces the radiotherapeutic sensitivity. Therefore, T63 has a potential as a preventive or therapeutic agent for treating NPC.     

Curcumin analogue B67 induces apoptosis and G2/M arrest to suppress radioresistant nasopharyngeal carcinoma cells

AIM: To study the effect of curcumin analogues B67 on radioresistant nasopharyngeal carcinoma cells (CNE-2R). METHODS: The effects of B67 on the cell viability and proliferation of CNE-2R and the parent cells CNE-2 were detected by MTT assay and colony formation assay, respectively. The changes of cell cycle, apoptosis and mitochondrial membrane potential were determined by flow cytometry. The morphological changes of the cells were observed under fluorescence microscope. Node mice were subcutaneously inoculated with the cells to determine the tumorigenic ability. RESULTS: The IC₅₀ of B67 on the viability of CNE-2R cells after treatment for 24 h, 48 h and 72 h were 3.96,2.59 and 0.89 μmol/L, respectively, and those of CNE-2 cells were 8.84, 3.55 and 1.10 μmol/L,respectively. The IC₅₀ of B67 on the proliferation of CNE-2R cells after treatment for 48 h was 0.55 μmol/L, and that of CNE-2 cells was 0.73 μmol/L. After treated with B67 for 24 h, CNE-2R and CNE-2 cells at G₂/M stage increased from 5.32% to 40.01% and from 9.07% to 15.73%,respectively. After treated with B67 for 48 h, the apoptosis of CNE-2R and CNE-2 cells increased from 5.49% to 38.06% and from 4.99% to 35.74%, respectively. The mitochondrial membrane potential in CNE-2R and CNE-2 cells was decreased by 66.76% and 72.09%, respectively. After treated with B67 for 24 h, the tumorigenic rate of CNE-2R cells was 0%, while the rates of CNE-2 cells in low- and high-concentration groups were 100% and 0%, respectively.CONCLUSION: Curcumin analogue B67 exhibits enhanced suppressive activity on radioresistant nasopharyngeal carcinoma cells by inducing G₂/M-phase arrest, promoting cell apoptosis and changing mitochondrial membrane potential.     

Effect of arctigenin on apoptosis of human nasopharyngeal carcinoma cell line CNE-1

AIM: To investigate the effect of arctigenin on the apoptosis of human nasopharyngeal carcinoma cell line CNE-1 and its potential mechanism. METHODS: The inhibition of cell viability was analyzed by CCK-8 assay. The activity of caspase-3 and caspase-9 was analyzed by caspase-3 and caspase-9 activity kit. Apoptotic cell percentage was evaluated by Annexin V-PI staining. The expression of PI3K/AKT/XIAP signal pathway-related molecules at mRNA and protein levels was analyzed by real-time PCR and Western blot. RESULTS: Arctigenin inhibited the cell activity in a dose- and time-dependent manner after treatment with arctigenin at concentrations of 10, 20, 40 and 80 μmol/L for 24 h, 48 h and 72 h (P<0.01). Arctigenin also increased the activity of caspase-3 and caspase-9 and the apoptotic rate (P<0.05), and down-regulated the mRNA and protein expression of PI3K/AKT/XIAP signal pathway-related molecules (P<0.05).CONCLUSION: Arctigenin induces the apoptosis of CNE-1 cells through PI3K/AKT/XIAP signal pathway.     

Effects of tamoxifen on volume-activated Cl- currents of nasopharyngeal carcinoma cells at different stages of the cell cycle

AIM:To investigate the inhibitory effects of Cl- channel blocker, tamoxifen, on volume-activated Cl- currents of nasopharyngeal carcinoma cells (CNE-2Z cells) in G₁ and S phases. METHODS:Highly synchronous cells in G₁ phase and S phase were obtained by the serum starvation and the double-block techniques. The whole-cell patch clamp technique was used to observe the effects of tamoxifen on volume-activated Cl- currents and to analyze the anion permeability of volume-activated Cl- channels. RESULTS:47% hypotonic stimulation activated a Cl- current in the nasopharngeal carcinoma cells at the cell cycle stage G₁ phase and S phase. Tamoxifen at concentration of 10 to 30 μmol/L completely inhibited the current. However, the time needed to completely inhibit the current was dose-dependent and was different between G₁ phase and S phase. The time needed to completely inhibit the current was shorter in G₁ cells than that in S phase cells. The anion permeability sequence of the volume-activated Cl- channel was I->Cl->gluconate in both G₁ phase and S phase cells. The permeability of G₁ phase cells to I- was higher than that in S phase cells, but to gluconate was lower than that in S phase cells. CONCLUSIONS:The density of the volume-activated Cl- current, the anion permeability of the channel and the sensitivity of the current to tamoxifen were different between the CNE-2Z cells in G₁ phase and those in S phase. The results suggest that the expression of tamoxifen-sensitive, volume-activated chloride channels is differentiated at different stages of the cell cycle.     

Effects of EBV infection on growth and apoptosis of nasopharyngeal carcinoma cell line

AIM: To explore the effect of EBV infection on growth and apoptosis of nasopharyngeal carcinoma(NPC) cell line.METHODS: NPC cell line CNE1 was directly infected by Epstein Barr virus (EBV). The expression of EBV-latent membrane protein 1 (EBV-LMP1) and bcl-2 were detected by immunohistochemistry method (LSAB). The growth of NPC cells was identified by MTT method. Apoptotic carcinoma cells were detected by flow cytometry analysis and the terminal deoxynucletidyl transferase-medicated dUTP-biotin nick end labeling (TUNEL) methods. RESULTS: EBV-LMP1 was positive in CNE1 infected by EBV(E-CNE1). Compared with CEN1, the growth of E-CNE1 apparently increased (P＜0.01). No apoptotic carcinoma cells were detected and bcl-2 postive cells were 2%~3% respectively in 2 kinds of NPC cells.CONCLUSION: Growth of NPC cells is enhanced by EBV infection and EBV-LMP1 expression, but no influence on expression of bcl-2 and apoptosis of NPC cells.     

Effects of EBV infection on growth and apoptosis of nasopharyngeal carcinoma cell line

AIM:To explore the effect of EBV infection on growth and apoptosis of nasopharyngeal carcinoma(NPC)cell line.METHODS:NPC cell line CNE1 was directly infected by Epstein Barr virus(EBV).The expression of EBV-latent membrane protein 1(EBV-LMP1)and bcl-2 were detected by immunohistochemistry method(LSAB).The growth of NPC cells was identified by MTT method.Apoptotic carcinoma cells were detected by flowcytometry analysis and the terminal deoxynucletidyl transferase-medicated dUTP-biotin nick end labeling(TUNEL)methods.RESULTS:EBV-LMP1 was positive in CNE1 infected by EBV(E-CNE1).Compared with CEN1, the growth of E-CNE1 apparently increased(P<0.01).No apoptotic carcinoma cel s were detected and bcl-2 postive cells were 2%~3%respectively in 2 kinds of NPC cells.CONCLUSION:Growth of NPC cells is enhanced by EBV infect ion and EBV-LMP1 expression, but no influence on expression of bcl-2 and apoptosis of NPC cells.     

Synergistic anti-proliferation effect of aspirin and 5-fluorouracil on colon cancer cells and its mechanism

AIM：To investigate the synergistic anti-proliferation effect of aspirin and 5-fluorouracil on the colon cancer cells and its mechanism. METHODS：Colon cancer cells were divided into 4 groups: control group, aspirin group, 5-fluorouracil group and aspirin+5-fluorouracil group. Synergistic anti-proliferation effect of aspirin and 5-fluorouracil on the colon cancer cells was observed by MTT assay. Apoptosis-inducing effect and mechanism were detected by Hoechst 33258 staining, caspase activity assay and flow cytometry analysis. The mRNA and protein levels of apoptosis-related proteins were evaluated by real-time PCR and Western blotting. RESULTS：5-Fluorouracil inhibited proliferation of HCT116 and SW620 colon cancer cells effectively, and low concentration of aspirin exerted synergistic inhibitory effect. 5-Fluorouracil induced apoptotic morphology and increased caspase activity and sub-G1 phase in HCT116 cells. The synergistic effect of aspirin obviously enhanced apoptotic ratio and caspase activity. Moreover, 5-fluorouracil inhibited the mRNA and protein expression of Bcl-2, which was amplified by low concentration of aspirin. CONCLUSION：Aspirin and 5-fluorouracil had a synergistic anti-proliferation effect on the colon cancer cells through apoptosis pathway.     

miRNA-7-mediated Bax/Bcl-2 expression promotes apoptosis of human nasopharyngeal carcinoma CNE-1 cells

AIM: To investigate the relationship of microRNA-7 (miRNA-7) over-expression and Bax/Bcl-2 expression in human nasopharyngeal carcinoma CNE-1 cells.METHODS: The CNE-1 cells were transfected with miRNA-7 mimics using Lipofectamine 2000. The expression of miRNA-7 was detected by real-time PCR. CCK-8 assay and Hoechst 33258 staining were used to detect the cell activity and apoptosis. The expression of Bax/Bcl-2 at mRNA and protein levels was determined by real-time PCR and Western blot. RESULTS: The expression of miRNA-7 was increased significantly in the CNE-1 cells compared with negative control group and mock group (P<0.01). The activity of CNE-1 cells were extremely decreased after tansfected with miRNA-7 mimics (P<0.01). The typical apoptotic nuclear morphological changes were observed in the CNE-1 cells under the fluorescence microscope with Hoechst 33258 staining. The expression of Bax at mRNA and protein levels was significantly increased compared with the other 2 groups (P<0.01), while the Bcl-2 expression at mRNA and protein levels was significantly down-regulated (P<0.01).CONCLUSION: Over-expression of miRNA-7 significantly inhibits the growth and promotes the apoptosis of nasopharyngeal carcinoma CNE-1 cells by increasing the expression of Bax and down-regulating Bcl-2.     

Bufalin activates chloride channels in poorly differentiated nasopharyngeal carcinoma cells

AIM: To investigate the activation of chloride channels induced by bufalin and the properties of the channels in poorly differentiated nasopharyngeal carcinoma (CNE-2Z) cells. METHODS: The technique of whole-cell patch clamp was used to record the chloride currents and to analyze the characteristics of the currents in CNE-2Z cells.RESULTS: A chloride current was slowly activated by extracellular application of bufalin (1 μmol/L). The activation of the current was slower than that of the volume-activated chloride current, with an activation latency of(12.1±6.4) min. The reversal potential of the current was close to the calculated Cl^- equilibrium potential (E_Cl =-0.9 mV). The chloride current was outward-rectified and did not show significant time-dependent or voltage-dependent inactivation. The chloride channel blocker tamoxifen completely inhibited the outward and inward currents. The current was also completely inhibited by extra-cellular application of 47% hypertonic solution. CONCLUSION: Bufalin activates chloride channels and induces a chloride current in CNE-2Z cells. Compared with the volume-activated chloride current in CNE-2Z cells, the activation latency of the bufalin-induced current is longer and the outward rectification is more obvious.     

Effect of microtubule-destabilizing protein stathmin gene silencing on proliferation and apoptosis of nasopharyngeal carcinoma cell line 5-8F

AIM: To investigate the effects of stathmin gene silencing on nasopharyngeal carcinoma cell line 5-8F. METHODS: Double-strand siRNA targeting to stathmin gene was obtained by chemical synthesis and annealing, and was sub-cloned into the vector pGenesil-1.1. The plasmid was introduced into 5-8F cells by liposome-mediated transfection. The gene expression of stathmin, and the proliferation, morphology and apoptosis of the cells were analyzed by Western blotting, MTT assay and flow cytometry. RESULTS: The cell suppression rate in stathmin gene silencing group was (53.01?1.12)%, significantly higher than that in transfection reagent group and in negative control group. The cell apoptotic rate in stathmin gene silencing group was (8.75?0.67)%, also significantly higher than that in transfection reagent group and in negative control group (P<0.05). CONCLUSION: Silencing of stathmin gene in nasopharyngeal carcinoma cells inhibits the cell proliferation and induces cell apoptosis.     

Molecular mechanism underlining ethanol-induced chloride currents in nasopharyngeal carcinoma cells

AIM：To study the effects and mechanisms of ethanol on chloride channels in poorly differentiated nasopharyngeal carcinoma CNE-2Z cells. METHODS：The effect of ethanol on the cell growth was analyzed by MTT assay. The technique of whole-cell patch-clamp was used to detect the chloride current. The characteristics of the chloride current were analyzed by using the chloride channel blockers. The siRNA technique was used to analyze the molecular basis of the ethanol-sensitive chloride channels. RESULTS：Under isotonic conditions, the background current was weak and stable. Ethanol at concentrations of 0.17~170 mmol/L activated a chloride current in a concentration-dependent manner (an inverted U-shape), with a maximum effect at the concentration of 17 mmol/L. The currents showed obviously outward rectification and were susceptible to extracellular hypertonicity and the chloride channel blocker, 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB). ClC-3 siRNA obviously decreased the currents activated by ethanol. CONCLUSION：Extracellular ethanol induces chloride currents through activating the ClC-3 chloride channels.     

Inhibitory effect of JIP on AP-1 activity induced by LMP1 in nasopharyngeal carcinoma cells and its mechanism

AIM: To investigate the mechanism of the AP-1 signal transduction pathway inhibited by JIP in nasopharyngeal carcinoma cells. METHODS: AP-1 activity was triggered by Dox-induced LMP1 expression in Tet-on-LMP1-HNE₂ cells (L7). The retention of phospho-JNK in the cytoplasm caused by JIP was examined with immunofluroscence assay. RESULTS: 24 h after transfection of L7 cells with the JIP expression plasmid, the translocation of activated JNK was inhibited, which resulted in the retention of phospho-JNK in the cytoplasm and down-regulation of the AP-1 activity. CONCLUSION: JIP down-regulates the activity of AP-1 through the inhibition of the translocation of JNK.     

Effect of transketolase-like protein 1 on proliferation of human nasopharyngeal carcinoma cells

AIM: To investigate the effect of transketolase-like protein 1 (TKTL1) on proliferation of human nasopharyngeal carcinoma cells in vitro. METHODS: The siRNA against TKTL1 mRNA was constructed and transfected into human nasopharyngeal carcinoma cells (CNE cell line). The activity of transketolase was detected before and after RNA interference.Real-time PCR was used to determine the mRNA expression of transketolase (TKT) gene family in the CNE cells.Flow cytometry and MTT test were used to detect the effect of anti-TKTL1 siRNA on cell proliferation and cell cycle in the CNE cells. RESULTS: The total transketolase activity was significantly decreased in the CNE cells transfected with siRNA TKTL1 construct compared with the cells transfected with control vector or untransfected CNE cells. No significant difference in the expression level of TKT and TKTL2 gene between the CNE cells transfected with siRNA TKTL1 construct and the cells transfected with control vector or untransfected CNE cells was observed (P>0.05). However, the expression level of TKTL1 gene was significantly downregulated in the CNE cells transfected with siRNA TKTL1 construct compared with the cells transfected with control vector.Cancer cells were arrested in G0/G1 phase, and cancer cell proliferation was significantly inhibited in the CNE cells transfected with siRNA TKTL1 construct. CONCLUSION: TKTL1 plays an important role in the total transketolase activity and cell proliferation of human nasopharyngeal carcinoma. TKTL1 may be considered as a potential target for novel anti-cancer therapy.     

Effects of PKC-α asODN and PKA-ⅠasODN on growth and proliferation of the CNE-2Z cells of nasopharyngeal carcinoma

AIM:To investigate the effects of antisense oligonucleotides (asODN) of PKC-α and PKA-Ⅰon growth and proliferation of the CNE-2Z cells.METHODS:The expression of PKC-α and PKA-Ⅰ was observed with immunohistochemistry method. The asODNs of (1)PKC-α, (2)PKA-Ⅰ, (3)PKC-α and PKA-Ⅰ, were transfected into CNE-2Z cells by lipofectin (LP), and a random sequence as a control was used. The cell growth index (GI) and the clone formation rate of CNE-2Z were detected by MTT colorimetric assay and soft agar assy, respectively.RESULTS:The expression of PKC-α or PKA-Ⅰin CNE-2Z in experimental group were both significantly lower than that of control group(P<0.05). The GI and clone formation rates of CNE-2Z cells transfected by PKC-α and PKA-ⅠasODN with concentrations ranging from 0.05 μM to 1.00 μM were lower significantly than that of control groups(P<0.05), and there was a dose-dependent relationship among them. The inhibitory effects of PKC-α and PKA-ⅠasODNs both on the cell growth index (GI) and clone formation rates were more significant than that of control group(P<0.01),and the GI were significantly lower than that of the other experimental groups(P<0.05).CONCLUSION:PKC-α asODN and PKA-ⅠasODN inhibited CNE-2Z growth and proliferation in vitro, and a synergetic inhibitory effect of PKC-α asODN and PKA-ⅠasODN was also observed.     

Osmolarity,cell volume and proliferation in nasopharyngeal carcinoma cells

AIM: To investigate the relationship between osmolarity, cell volume and cell proliferation in nasopharyngeal carcinoma cells. METHODS: MTT method was applied to detect the proliferation ability of the poorly-differentiated nasopharyngeal carcinoma cell (CNE-2Z) under various osmolarity conditions. The flow cytometry was used to analyse cell cycle distribution. Cell volume was obtained by the image analysis of living cells and cell viability was determined by the trypan blue assay. RESULTS: Cultivation of cells under the hypertonic conditions of 370 and 440 mOsmol/L increased cell volume by 8.7% and 27.8% and facilitated cell proliferation by 22.2% and 33.9%, respectively. However, hypotonic incubation of cells with osmolarity of 160 and 230 mOsmol/L decreased cell volume by 12.8% and 4.1% and inhibited cell proliferation by 34.0% and 15.6%, respectively. Cell volume was positively correlated with cell proliferation rate. Long-term cultivation of cells under anisotonic conditions did not significantly alter cell cycle distribution, but hypotonic cultivation decreased cell viability. CONCLUSION: Proliferation of nasopharyngeal carcinoma cells was closely correlated with the osmolarity of culture medium and cell volume. Hypotonic cultivation may inhibit cell proliferation by decreasing cell volume to facilitate cell death mechanisms.     

Role of Cl- in regulatory volume decrease of nasopharyngeal carcinoma cells

AIM:To clarify the role of Cl^- in regulatory volume decrease (RVD) of nasopharyngeal carcinoma cells (CNE-2Z).METHODS:Analysis of living cell images was used to detect the volume changes following exposure to hypotonic solution. Iron replacement and block of iron channels were also applied in the present study. RESULTS:Extracelluar hypotonic treatment made the cells swell and induced RVD. The RVD was correlated positively to the swelling in the range of 160-230 mOsmol/L. Substitution of gluconate for Cl^- in perfusing solutions markedly increased RVD. Depletion of cellular Cl^- abolished, and chloride channel blockers inhibited RVD. CONCLUSION:Cl^- is the key iron to establish the RVD in CNE-2Z cells. Activation of Cl^- channels and Cl^- efflux are the major mechanisms of RVD.     

Role of Wnt signaling pathway in development of radioresistance in esophageal cancer

AIM:To investigate the role of Wnt signaling pathway in the development of radioresistance in esophageal cancer cells. METHODS:The mRNA expression of the genes involved in Wnt signaling pathway was determined by real-time RT-PCR. The protein levels involved in Wnt signaling pathway were also confirmed by Western blotting and immunofluorescence method. Xenograft assay was performed to compare the proliferation ability and tumorigenicity of the cell lines. RESULTS:Up-regulation of Wnt1 induced the activation of Wnt signaling pathway and the variation of the downstream genes. β-catenin was accumulated and nuclear-transferred. The expression of downstream targeted genes such as cyclin D1 and WISP1 was increased. The radioresistant esophageal cancer cells showed higher proliferation ability and tumorigenicity in nude mouse xenograft. CONCLUSION:Wnt signaling-induced acceleration of proliferation is important for the development of radioresistance in esophageal cancer cells.     

siRNA targeting TRIM29 gene induces apoptosis of nasopharyngeal carcinoma cells by inhibiting PI3K/AKT signaling pathway

AIM:To investigate the effect of TRIM29 gene expression silencing on the apoptosis and PI3K/AKT signaling pathway in human nasopharyngeal carcinoma 5-8F cells. METHODS:The 5-8F cells were divided into blank group, negative control (NC) group (transfected negative control siRNA) and si-TRIM29 group (transfected TRIM29 specific siRNA). The viability of the 5-8F cells transfected with si-TRIM29 for 0~96 h was measured by CCK-8 assay. The apoptotic rate and the protein levels of TRIM29, cleaved caspase-3, cleaved caspase-9, Bcl-2, Bax, t-AKT and p-AKT in the 5-8F cells transfected with si-TRIM29 for 48 h were determined by flow cytometry and Western blot, respectively. PI3K/AKT signal specific inhibitor LY294002 at 10 μmol/L and si-TRIM29 alone or in combination were treated with the 5-8F cells, and the cells were divided into blank group, LY294002 group and LY294002+si-TRIM29 group. The apoptotic rates in the 3 groups were detected by flow cytometry. RESULTS:The protein expression of TRIM29 in the 5-8F cells transfected with TRIM29 siRNA was significantly lower than that in blank group (P<0.05). Compared with blank group, the cell viability was significantly decreased, the apoptotic rate was significantly increased, the protein levels of cleaved caspase-3, cleaved caspase-9 and Bax were significantly increased, and the protein levels of Bcl-2 and p-AKT were significantly decreased in si-TRIM29 group (P<0.05). The apoptotic rate in LY294002 group was higher than that in blank group, while that in LY294002+si-TRIM29 group was even higher than that in LY294002 group (P<0.05). CONCLUSION:Silencing of TRIM29 gene expression induces apoptosis of nasopharyngeal carcinoma 5-8F cells by inhibiting PI3K/AKT signaling pathway.