Transforming growth factor α promotes the proliferation,migration and adhesion of human endothelial progenitor cells

AIM: To explore the effects of transforming growth factor-α (TGF-α) in the monoclonal formation, proliferation, migration and adhesiveness of human endothelial progenitor cells (EPCs). METHODS: The isolated and cultured EPCs were treated with various concentrations of TGF-α (final concentrations of 1, 5, 10 μg/L, respectively). At the same time, the PBS control and epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) group (10 μg/L TGF-α plus 1: 1 000 EGFR-TKI) were set. The effects of TGF-α on monoclonal formation, proliferation, migration and adhesiveness of EPCs were determined by clone formation experiment, thiazolyl blue tetrazolium bromide (MTT), EdU, Transwell and adhesion assays, respectively. The expression of epithelial growth receptor (EGFR) and vascular endothelial growth factor (VEGF) were measured by Western blotting. RESULTS: Different concentrations of TGF-α all significantly induced the monoclonal formation, proliferation, migration and adhesiveness of EPCs (P<0.01), which were inhibited by EGFR-TKI. The results of Western blotting showed that TGF-α also induced the expression of EGFR and VEGF with a certain concentration effect (P<0.01). CONCLUSION: By combining with EGFR induced the expression of VEGF, TGF-α significantly promotes the related cell function of monoclonal formation, proliferation, migration, adhesiveness in EPCs.     

Effect of oncogenic microRNA-106a on growth of normal gastric mucous epithelial cells and gastric cancer cells

AIM: To investigate the oncogenic effect of microRNA-106a (miR-106a) on normal gastric mucous epithelial cells and gastric cancer cells.METHODS: The miR-106a mimic was transfected into normal gastric mucous epithelial cell line GES-1 using liposome. The change of cell growth was measured by MTT assay. The miR-106a inhibitor was transfected into gastric cancer cell lines MGC-803 and SGC-7901 using liposome, and the changes of cell cycle distribution and cell cycle-related protein expression were measured by flow cytometry and Western blotting,respectively. The growth of gastric cancer was also observed using nude mouse xenograft model. RESULTS: The miR-106a mimic increased the growth of GES-1 cells in a dose-dependent manner. By decreasing the expression of cyclin-dependent kinase (CDK) 1 and CDK2, the miR-106a inhibitor arrested MGC-803 cells at G₀/G₁ and G₂/M phases. The miR-106a inhibitor also arrested SGC-7901 cells at G₂/M phase by decreasing the expression of CDK1. The results of animal experiments showed that the miR-106a inhibitor significantly suppressed the tumor growth in a dose-dependent manner.CONCLUSION: miR-106a may play an important role in the development of gastric cancer.     

Effect of epidermal growth factor receptor antibody on human colon carcinoma

AIM: To observe the effect of monoclonal antibody of epidermal growth factor receptor(EGFR) on human colon carcinoma cell lines. METHODS: Cell counting, growth curve measurement and MTT method were applied in this study to examine the proliferation of cultured cells in vitro when different dosage of EGFR McAb is used to treat LST174 colon carcinoma cell lines. RESULT: The proliferation of cultured human colon carcinoma cells could be significantly inhibited in a dose dependent manner by EGFR antibody Compared with the control group, the cell number was decreased by 61.3% and 33.8% respectively when treated with 0.625 mL/L or 2.5 mL/L of EGFR McAb CONCLUSION: EGFR McAb can inhibit cell growth of human colon carcinoma LST174.     

Effects of alginate dressing and mouse epidermal growth factor combination therapy on epidermal stem cells in patients with refractory wound

AIM: To evaluate the effect of combination therapy with alginate dressing and mouse epidermal growth factor (mEGF) on proliferation and differentiation of epidermal stem cells (ESCs) in patients with refractory wound.METHODS: Eighteen cases,12 males and 6 females,aged from 18 to 61 years (mean 36.4 years),of skin defects therapy by dressing changing for one month were selected in this study.The wounds were 11 in the foot,3 in the calf,2 in the thigh and 2 in the forearm.All the patients were randomly divided into 3 groups: alginate dressing and mEGF group (n=6),mEGF group (n=6) and control group (n=6).The wound closure indexes were measured at 7th,14th,21st and 28th days.The samples were harvested at 7th and 14th days after treatment for pathologic examination.The positive staining cells of cytokeration 10 (CK10) and cytokeration 15 (CK15) were evaluated by SP immunohistochemical staining technique.RESULTS: The wound healing was promoted in group A and group B.However,the wound closure index was increased in group A (P<0.05).Pathological examination showed the epidermis was thicker in group A than that in group B and C.Treatment by the alginate dressing combined with the mEGF,angiogenesis was active and granulation was enhanced.As compared with group B and group C,SP immuohistochemical staining technique showed that the ESCs in group A were bigger in size and larger in number.There was significant difference between group A and group B (or C) in the proliferation and differentiation of ESCs.CONCLUSION: Combined therapy with alginate dressing and mEGF shows a better result than that with mEGF only in proliferation and differentiation of ESCs of patients with refractory wound.     

Double TdR blocking induces synchronization of cell cycle in human gastric cancer SGC-7901 cells

AIM: To investigate the effects of double thymidine deoxyribonucleoside (TdR) blocking on the cell cycle of human gastric cancer SGC-7901 cells.METHODS: SGC-7901 cells in the logarithm period were selected in the study and treated with TdR at concentration of 2 mmol/L, 4 mmol/L or 8 mmol/L for 15 h as the first blocking. After incubation in TdR-free medium for 10 h, the cells were treated with TdR at same concentrations again for another 15 h as the second blocking. The blocked cells were released by washing in fresh medium twice and incubation in TdR-free medium containing 10% fetal bovine serum for 12 h. The cells were collected and the cell cycle was detected by flow cytometry.RESULTS: By double TdR (2 mmol/L, 4 mmol/L and 8 mmol/L) blocking to synchronize the cell cycle, the cells in G₀/G₁ phase accounted for 77.3%, 77.5% and 77.0%, respectively. After further incubation for 12 h in TdR-free medium, the proportion of the cells in each phase of the cell cycles returned to normal range. CONCLUSION: The method of double TdR blocking is an ideal access in short term to acquire a large number of cells in G₀/G₁ phase.     

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.     

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.     

Effects of isorhapontigenin on cell cycle arrest and down-regulation of cyclin D1 expression in bladder cancer cells

AIM：To explore the inhibitory mechanism of isorhapontigenin (ISO) on the proliferation, migration and invasion of UMUC3 bladder cancer cells. METHODS：Human UMUC3 bladder cancer cells were pretreated with ISO, and the proliferation of the cells was observed under phase-contrast microscope and by ATPase assay. The expression of cyclin D1 was determined by RT-PCR and Western blotting. The cell cycle alteration was detected by flow cytometry, and the cell migration was examined by wound-healing assay. RESULTS：Over 20 μmol/L of ISO significantly inhibited the proliferation of UMUC3 cells with the IC50 of (22.5±2.8) μmol/L. The mRNA and protein levels of cyclin D1 in UMUC3 cells were markedly decreased after treatment with ISO. Exposure of UMUC3 cells to low dose (5 μmol/L) of ISO led to significant induction of G0/G1 growth arrest at both 12 h (58.82%) and 24 h (63.94%), compared with the negative control cells (47.33%) without inducing obvious apoptosis. ISO at dose of 5 μmol/L also markedly inhibited the cell migration. CONCLUSION：ISO significantly exhibits inhibitory effects on the proliferation and migration of human bladder cancer cells by down-regulation of cyclin D1 expression accompanying with G0/G1 cell cycle arrest.     

Effect of over-expression of transcription factor CDX2 on proliferation and cell cycle of human gastric cancer cell line SGC-7901

AIM: To study the effect and the molecular mechanism of CDX2 over-expression on the proliferation, growth and cell cycle of human gastric cancer cell line SGC-7901. METHODS: The SGC-7901 cells in LV-CDX2-GFP group were transfected with the recombinant lentivirus vector LV-CDX2-GFP, the cells in LV-GFP group were transfected with the negative control lentiviral vector for the negative control, and the cells in blank control group were without any treatment. The cell proliferation was detected by CCK-8 assay. The cell cycle distribution was analyzed by flow cytometry. The expression of CDX2, Bax, Bcl-2, cyclin D1 and survivin was determined by semi-quantitative RT-PCR and Wes-tern blotting. RESULTS: Compared with LV-GFP group and blank control group, the proliferation activity of the SGC-7901 cells was significantly lower (P<0.05), the G0/G1 phase proportion increased (P<0.05), the mRNA and protein levels of Bcl-2, cyclin D1 and survivin were reduced (P<0.05), and the mRNA and protein levels of Bax were up-regulated (P<0.05) in LV-CDX2-GFP group. No statistically significant difference of the above indexes was observed (P>0.05) between LV-GFP group and blank control group. CONCLUSION: Over-expression of CDX2 mediated by lentivirus inhibits the proliferation and growth of human gastric cancer SGC-7901 cells and arrestes the cell cycle at G0/G1 phase, which may be related to down-regulation of Bcl-2, cyclin D1 and survivin and up-regulation of Bax.     

Effect of Bmi-1 gene overexpression on proliferation of human gastric mucosal epithelial cell line GES-1

AIM: To investigate the effect of B lymphoma Moloney murine leukemia virus insertion region 1 ( Bmi-1 ) gene overexpression on the proliferation of a human normal gastric epithelial cell line GES-1. METHODS: The plasmid containing Bmi-1 gene or empty plasmid was transfected into GES-1 cells by retroviral mediation. The expression of Bmi-1 at mRNA and protein levels was detected by quantitative real-time PCR (qRT-PCR) analysis and Western blotting, respectively. The effect of Bmi-1 gene overexpression on the cell cycle of GES-1 cells was evaluated by flow cytometry. The proliferation of the stably transfected cells was measured by Cell Counting Kit-8. RESULTS: The results of qRT-PCR analysis and Western blotting demonstrated that stably transfected cell line was successfully established. The results of flow cytometry analysis showed that overexpression of Bmi-1 reduced the G₀/G₁ phase, arrested the cells in G₂/M phase and S phase. The growth curve showed that overexpression of Bmi-1 resulted in increased growth speed. CONCLUSION: Increase in Bmi-1 gene expression regulates the cell cycle and promotes the proliferation of GES-1 cells.     

Klebsiella pneumoniae capsular polysaccharide induces secretion of cytokines in bronchial epithelial cells via EGFR signaling pathway

AIM: To investigate the role of epidermal growth factor receptor (EGFR) in the secretion of inflammatory cytokines in human bronchial epithelial BEAS-2B cells induced by Klebsiella pneumoniae (KP) capsular polysaccharide (CPS). METHODS: KP was cultured in vitro, and the CPS was extracted. The BEAS-2B cells were stimulated with CPS at different concentrations, and the levels of tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) in the supernatant were measured by ELISA. The phosphorylation level of EGFR was detected by Western blot at different time points after stimulation. After pretreatment of the BEAS-2B cells with EGFR inhibitor AG1478, the phosphorylation level of ERK was detected by Western blot, the nuclear translocation of P65 was detected by indirect immunofluorescence, and the levels of TNF-α and IL-8 in the supernatant of the cells were measured. Finally, the levels of TNF-α and IL-8 in the culture supernatant of CPS-stimulated cells were detected by ELISA after pretreated with ERK inhibitor PD98059 and NF-κB inhibitor PDTC. RESULTS: Exposure to CPS at 10 mg/L for 12 h significantly induced the BEAS-2B cells to secret TNF-α and IL-8. The phosphorylation levels of EGFR and ERK and the nuclear translocation of p65 in the BEAS-2B cells were significantly increased after CPS stimulation (P<0.05). The phosphorylation level of ERK and the nuclear translocation of p65 were significantly reduced in the cells pretreated with EGFR inhibitor AG1478. Furthermore, the levels of TNF-α and IL-8 in the supernatant were significantly decreased after pretreated with the inhibitors of EGFR, ERK and NF-κB. CONCLUSION: Klebsiella pneumonia capsular polysaccharide activates the ERK and NF-κB signaling pathways via EGFR, and then induced the secretion of inflammatory cytokines TNF-α and IL-8 in the bronchial epithelial cells, indicating that EGFR may be a key factor in the inflammatory response induced by KP infection.     

ER-α36 and miR-143 involved in invasion of gastric cancer cells

AIM: To investigate the relationship between the expression of estrogen receptor α36 (ER-α36) and the invasion of gastric cancer cells. METHODS: SGC7901 cells were treated with 17β-estradiol at high or low concentration. The invasion of gastric cancer cells and the expression of ER-α36 were detected. The SGC7901 cells with the characteristics of stable low expression and high expression of ER-α36 were constructed. The invasion ability and microRNA sequences were determined in above-mentioned recombinant cells. RESULTS: The decreased invasion ability and ER-α36 expression were detected in SGC7901 cells treated with low concentration of 17β-estradiol. The situation was the opposite in the cells treated with high concentration of 17β-estradiol. The expression of miR-143 was significantly decreased in the SGC7901 cells with stable high expression of ER-α36 and was increased in the SGC7901 cells with stable low expression of ER-α36. CONCLUSION: The expression of ER-α36 is positively related to the invasion of gastric cancer cells. It is possible that miR-143 plays an important role in the regulation of gastric cancer invasion.     

Protective effect of human insulin-like growth factor 1 gene transfection on rat skeletal myoblasts with ischemic/reperfusion injury

AIM: To observe the protective effect of human insulin-like growth factor 1 (hIGF-1) on rat skeletal myoblasts with ischemic/reperfusion injury. METHODS: Myoblasts were isolated from SD rats, cultured, purified, and transfected with plasmid pLghIGF-1SN or pLgGFPSN. The myoblasts were divided into insulin-like growth factor (IGF) group (myoblasts transfected with pLghIGF-1SN), green fluorescent protein (GFP) group (myoblasts transfected with pLgGFPSN), and control group (untransfected myoblasts). The expression of hIGF-1 in myoblasts was investigated by immunocytochemistry, RT-PCR and ELISA. The proliferation rate of myoblasts 14 days after transfection was detected. To observe the protective effect of IGF-1 gene on skeletal myoblasts with ischemic/reperfusion injury 7 days after transfection, the apoptotic myoblasts were detected by the method of in situ TdT-mediated dUTP nick end labeling (TUNEL). The expression of bax and bcl-2 mRNA was detected by RT-PCR, and the expression of caspase-3 was determined by Western blotting. RESULTS: The expression of hIGF-1 in myoblasts transfected with pLghIGF-1SN was detected by immunocytochemistry, RT-PCR and ELISA, but not in myoblasts transfected by pLgGFPSN and untransfected myoblasts. The proliferation rate of myoblasts in IGF group was higher than that in other groups (P<0.05). The results of RT-PCR showed that the expression of bax mRNA significantly decreased and bcl-2 mRNA significantly increased in IGF group compared with GFP group (P<0.05). The results of Western blotting showed that the expression of caspase-3 significantly decreased in IGF group compared with GFP group (P<0.05). CONCLUSION: The transfection of hIGF-1 gene mediated by a retroviral vector produces a protective effect in rat skeletal myoblasts with ischemic/reperfusion injury. The mechanisms may be associated with down-regulating the expression of Bax and caspase-3 and up-regulating Bcl-2 expression.     

Expression of low-density lipoprotein receptor after exposure to hepatocyte growth factor in human Tenon's capsule fibroblasts

AIM: To study the dynamic alteration of low-density lipoprotein receptor (LDLr) expression after exposure to hepatocyte growth factor (HGF) in human Tenon's capsule fibroblasts (HTFs).METHODS: HTFs were stimulated with HGF at different concentrations (0, 10, 20, 40, 80 and 160 μg/L) for 12, 24, and 48 h. The viability of HTFs was analyzed by MTT assay. The expression of LDLr at mRNA and protein levels were analyzed by real-time PCR and Western blot.RESULTS: The expression of LDLr at mRNA and protein levels was positively correlated with the viability of HTFs. HGF promoted the viability of HTFs in a time-and concentration-dependent manner. At the same time, HGF promoted the expression of LDLr in the same manner.CONCLUSION: Exposure of HTFs to HGF induces LDLr expression at high level, suggesting that over-expression of LDLr on the HTFs may be a target receptor for controlled drug delivery, particularly in anti-scarring therapy after glaucoma filtration surgery.     

Effect of antisense RNA targeting Polo-like kinase 1 on cell growth in A549 lung cancer cells

AIM: To investigate the effect of Polo-like kinase-1 (Plk1) depletion on cell cycle progression and cell growth in lung cancer cells.METHODS: A recombinant plasmid containing antisense RNA targeting Plk1 (pcDNA3-Plk1) was transfected into A549 cells by lipofectine. RT-PCR and Western blotting were used to examine Plk1 gene expression. Cell proliferation was evaluated by cell counting and BrdU labeling. Cell cycle distribution and apoptosis were examined by flow cytometry. Inhibition rate (IR) of vinorebline (NVB) was determined by MTT assay. RESULTS: After transfected with pcDNA3-Plk1 into A549 cells, the expression levels of Plk1 mRNA and protein were greatly decreased. Abnormal morphological changes of cells and growth inhibition were observed in pcDNA3-Plk1 transfected cells. The BrdU labeling index was significantly lower than that in control group (P<0.05). Cells showed a strong G₂/M arrest and apoptosis 72 h post transfection. IR of vinorebline in pcDNA3-Plk1 transfected groups was significantly higher than that in other groups. CONCLUSION: Antisense RNA targeting Plk1 is capable of suppressing Plk1 expression, and therefore, significantly inhibits cellular proliferation, induces cell cycle arrest and apoptosis. Moreover, the sensitivity of lung cancer cells to chemotherapy is increased.     

Lovastatin-induced G1 phase synchronization in human endometrial cancer JEC cells

AIM: To investigate the method of inducing G₁ phase synchronization in human endometrial cancer JEC Cells by lovastatin and the cell cycle progress of JEC cells after desynchronization. METHODS: The doubling time of JEC cells was detected by Cell Counting Kit-8 (CCK-8) assay. To determine the best lovastatin concentrations for G₁ synchronization, JEC cells were treated with lovastatin at concentrations of 10, 20, 30 and 40 μmol/L for 1× doubling time, and the cell cycle was detected using flow cytometry (FCM). To determine the best period of lovastatin treatment to achieve G₁ synchronization, JEC cells were treated with lovastatin at the best concentration for 0.5× to 2× doubling time, and the cell cycle was detected every 4 h using FCM. Furthermore, the cell cycle progress of JEC cells after desynchronization was also observed. RESULTS: The doubling time of JEC cells was almost 24 h. Treatment with lovastatin at the concentration of 20 μmol/L for 24 h achieved maximum G₁ arrest in JEC cells. Minimum G₁ phase and maximum S phase were observed after desynchronization for 16 h. CONCLUSION: Maximum G₁ synchronization of JEC cells is induced by lovastatin at the concentration of 20 μmol/L for 24 h. The JEC cells show minimum G₁ phase and maximum S phase after desynchronization for 16 h.     

Inhibition of cell proliferation and arrest of cell cycle progression by blocking Cl- channels in nasopharyngeal carcinoma cells

AIM: The roles of Cl^-channels in regulatory volume decrease (RVD), cell proliferation and cell cycle progression in nasopharyngeal carcinoma cells (CNE-2Z) were investigated. METHODS: Image analysis of living cells was used to detect the volume changes following exposure to hypotonic solutions. Cell viability was determined by the trypan blue assay. MTT method was applied to detected cell proliferation. The effect of the blocker on the cell cycle distribution was monitored by the flow cytometry. RESULTS: 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) inhibited RVD and cell proliferation in a dose-dependent manner. NPPB at the concentration of 100 μmol/L arrested cells in G₁ phase (G₁ population increased from 54% to 71% at 48 h after treatments), but did not significantly alter cell viability. CONCLUSION: Block of chloride channels suppressed cell proliferation by arresting cells in G₁ phase. The results suggest that activation of Cl^-channels and RVD is necessary for facilitating cells to proceed to the S phase from G₁ phase and maintaining cell proliferation.     

PI3K/mTOR dual inhibitor PF-04691502 induces apoptosis of human gastric cancer SGC-7901 cells

AIM:To determine the antitumor effect of PF-04691502, a dual inhibitor of phosphatidylinositol 3-kinase (PI3K)/Akt and mammalian target of rapamycin (mTOR), on the viability and apoptosis of human gastric cancer cell line SGC-7901.METHODS:Cell viability was analyzed by MTT assay. Cell cycle was detected by flow cytometry, and Annexin V-FITC/PI dual staining was used to detect cell apoptosis. Protein expression of p21, cyclin D1, caspase-3, caspase-8, caspase-9 and poly(ADP-ribose) polymerase (PARP) was determined by Western blotting. RESULTS:MTT assay and cell cycle analysis results indicated that PF-04691502 inhibited the viability of SGC-7901 cells in a dose-dependent manner, and arrested the cells in G1 phase. PF-04691502 down-regulated the expression of cyclin D1 and up-regulated the expression of p21. In addition, SGC-7901 cells treated with PF-04691502 showed typical characteristics of apoptosis, accompanied by activation of caspases and cleavage of PARP. CONCLUSION: The PI3K/mTOR dual inhibitor PF-04691502 induces the apoptosis and inhibited the growth of SGC-7901 cells, implicating its potential therapeutic value for the treatment of cancer.     

Perifosine inhibits cell proliferation and triggers apoptosis in human gastric cancer cell line SGC-7901 cells

AIM: To investigate the effect of perifosine, a novel inhibitor of Akt, on the cell proliferation and apoptosis in human gastric cancer cell line SGC-7901.METHODS: Cell growth inhibition was detected by MTT assay. Cell cycle was analyzed by flow cytometry. Annexin V-FITC apoptosis detection kit was used to determine apoptosis in the cells. Protein expression was examined by Western blotting.RESULTS: Akt phosphorylation was dose-dependently inhibited by perifosine in SGC-7901 cells. The results of MTT and cell cycle analysis indicated that perifosine inhibited the growth of human gastric cancer cells in a dose-dependent manner. Perifosine arrested the cell cycle progression at G₂ phase. Apoptosis induction became more effective with increasing the concentration of perifosine. The caspase cascade and its downstream effector poly(ADP-ribose) polymerase (PARP) were also activated upon perifosine treatment, and the level of Bcl-2 was down-regulated, whereas the protein level of Bax was up-regulated.CONCLUSION: The small molecule Akt inhibitor perifosine shows substantial anti-tumor activity in human gastric cancer cell line SGC-7901. Perifosine induces caspase-dependent apoptosis, and the key regulators include caspase-3, caspase-9 and Bcl-2.     

Rab11-FIP4 regulates migration and invasion of colorectal cancer cells through IGF1R

AIM To investigate the role, clinical implications and the underlying mechanisms of Rab11-family interacting protein 4 (Rab11-FIP4) in colorectal cancer (CRC). METHODS The expression levels of Rab11-FIP4 in CRC tissues and corresponding paracancerous tissues were compared by immunohistochemistry, Western blot and RT-qPCR. The above methods were also used to detect the expression levels of Rab11-FIP4 in CRC cells under normal environment and hypoxia. The patiens were divided into Rab11-FIP4 high expression group (n=61) and Rab11-FIP4 low expression group (n=39) according to the immunohistochemical staining score.The overall survival and recurrence time of the 2 groups were compared by Kaplan-Meier survival analysis. HCT116 and LoVo cells with stable over-expression of Rab11-FIP4 were constructed using a lentiviral system. The cytological characteristics effects of Rab11-FIP4 over-expression in CRC cells were examined by CCK-8 assay, clonogenic assay and the Transwell assay. The co-immunoprecipitation was used to detect the correlation between Rab11-FIP4 and insulin-like growth factor 1 receptor (IGF1R). Human phosphokinase array was performed to investigate the signaling pathhway affected by IGF1R in CRC cells with increased expression of Rab11-FIP4. The relationship between Rab11-FIP4 and hypoxia-inducible factor 1α (HIF-1α) was analyzed by tissue microarrays and dual-luciferase reporter assay. RESULTS Rab11-FIP4 expression was up-regulated in CRC tissues and high expression of Rab11-FIP4 was associated with poor prognosis of the patients with CRC (P<0.05). Over-expression of Rab11-FIP4 promoted the viability, migration and invasion of CRC cells (P<0.05). High expression of Rab11-FIP4 regulated ERK1/2 and AKT signaling pathway via IGF1R (P<0.05). Hypoxia promoted the activation of HIF-1α on the Rab11-FIP4 promoter, thereby up-regulating the expression of Rab11-FIP4 (P<0.05). CONCLUSION Rab11-FIP4 may act as an oncogene to regulate migration and invasion of colorectal cancer cells through IGF1R.