人大肠癌HCT-8/5-FU耐药细胞株的建立及P-gp测定

目的：建立人大肠癌多药耐药细胞株HCT-8/5- FU及并对其耐药机制进行探讨．方法：先采用较大剂量间歇诱导法进行筛选,再采用浓度梯度递增法作用,历时7mo,至HCT8细胞可长期在5-FU浓度为2．0mg/L的细胞培养液中稳定生长．电镜、HE染色观察2种细胞形态结构差异．体外细胞毒性实验观察他对5-FU ADM,DDP的耐药性．绘制亲本细胞和耐药细胞的体外生长曲线．罗丹明染色法检测其两种细胞P-gp功能表达．结果：HCT-8细胞株经7mo诱导,可在5-FU 2．0 g/L的培养液中稳定增殖,具有多药耐药性,命名为HCT-8/5-FU,该细胞株对5-FU的耐药指数为16．6,并对ADM,DDP有交叉耐药性．该细胞株体外群体倍增时间与亲本细胞差别不显著．HE染色观察耐药细胞胞体较亲本细胞大,细胞核不规则,可见双核、多形核,细胞形态不规则,呈多角形、细长形改变,可见巨核细胞．透射电镜下耐药细胞胞质内线粒体、内质网、溶酶体增多．流式细胞仪罗丹明染色法观察荧光强度曲线左移,提示耐药细胞有过度P-gp表达．结论：成功建立HCT-8/5-FU多药耐药细胞株．先采用较大剂量间歇诱导进行筛选,再采用浓度梯度递增法作用是诱导大肠癌耐药细胞株的较好方式．HCT-8/5-FU细胞株的耐药机制与P-糖蛋白表达有关．     

Retroviral transduction of a mutant methylguanine DNA methyltransferase gene into human CD34 cells confers resistance to O6-benzylguanine plus 1,3-bis(2-chloroethyl)-1-nitrosourea

Human CD34 cells express low levels of the DNA repair protein O⁶-alkylguanine-DNA alkyltransferase (AGT) and are sensitive to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). Gene transfer of the AGT gene, methylguanine DNA methyltransferase (MGMT), results in only modest BCNU resistance. Recently, an AGT inhibitor, O⁶-benzylguanine (BG), entered clinical trials. In preclinical studies, BG potentiated the cytotoxic effect of BCNU in tumors but increased toxicity to normal CD34 cells. We transferred a mutant MGMT containing a glycine-to-alanine mutation at position 156, resulting in marked resistance to BG, into Chinese hamster cells; the K562 cell line and human CD34 cells used the retroviral backbone MFG. In each instance, cells expressed increased AGT and were much more resistant to the combination of BG and BCNU than the parental cells or cells transduced with wild-type MGMT. Furthermore, the transduction efficiency in human CD34 cells was in excess of 70%, and the proportion of CD34 transduced cells resistant to the combination was >30%. Thus, retroviral-mediated transduction of a mutant MGMT into CD34 cells appears to be an effective way to induce selective resistance to a drug combination designed to overcome a significant resistance mechanism to nitrosoureas in tumors.     

β-escin reverses multidrug resistance through inhibition of the GSK3β/β-catenin pathway in cholangiocarcinoma

AIM: To develop a safe and effective agent for cholangiocarcinoma(CCA) chemotherapy. METHODS: A drug combination experiment was conducted to determine the effects of β-escin in c o m b i n a t i o n w i t h c h e m o t h e ra p y o n C C A c e l l s. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was performed to determine the effects of β-escin and common chemotherapeutics on the proliferation of human CCA cells(QBC939, Sk-Ch A-1, and MZ-Ch A-1). Immunocytochemistry was used to detect the expression of P-glycoprotein(P-gp) protein. Luciferase reporter assay was used to detect the activation of the Wnt/β-catenin pathway. The protein levels of P-gp, p S9-GSK3β, p T216-GSK3β, GSK3β, β-catenin, and p-β-catenin were further confirmed by western blotting.RESULTS: The drug sensitivity of QBC939 and QBC939/5-fluorouracil(5-FU) cells to 5-FU, vincristine sulfate(VCR), or mitomycin C was significantly enhanced by β-escin compared with either agent alone(P 0.05). In addition, the combination of β-escin(20 μmol/L) with 5-FU and VCR was synergic with a combination index 1. Further investigation found that the m RNA and protein expression of P-gp was downregulated by β-escin. Moreover, β-escin induced GSK3β phosphorylation at Tyr-216 and dephosphorylation at Ser-9, resulting in phosphorylation and degradation of β-catenin. Interestingly, activation of the GSK3β/β-catenin pathway induced by Wnt3 a resulted in upregulation of P-gp, which was effectively abolished by β-escin, indicating that β-escin down-regulated P-gp expression in a GSK3β-dependent manner.CONCLUSION: β-escin was a potent reverser of P-gpdependent multidrug resistance, with said effect likely being achieved via inhibition of the GSK3β/β-catenin pathway and thus suggesting a promising strategy of developing combination drugs for CCA.     

Value of α-fetoprotein in association with clinicopathological features of hepatocellular carcinoma

AIM:To explore the relationship between α-fetoprotein(AFP) and various clinicopathological variables and different staging system of hepatocellular carcinoma(HCC) thoroughly.METHODS:A retrospective cohort study of consecutive patients diagnosed with HCC between January 2008 and December 2009 in West China Hospital was enrolled in our study.The association of serum AFP values with the HCC clinicopathological features was analysed by univariate and multivariate analysis,such as status of hepatitis B virus(HBV) infection,tumor size,tumor number,vascular invasion and degree of tumor differentiation.Also,patients were divided into four groups at the time of enrollment according to different cutoff values for serum value of AFP(≤ 20 μg/L,21-400 μg/L,401-800 μg/L,and ≥ 801 μg/L),to compare the positive rate of patient among four groups stratified by various clinicopathological variables.And the correlation of different kinds of tumor staging systems,such as TNM,Barcelona Clinic Liver Cancer(BCLC) staging classification and China staging,were compared with the serum concentration of AFP.RESULTS:A total of 2304 HCC patients were enrolled in this study totally;the mean serum level of AFP was 555.3 ± 546.6 μg/L.AFP levels were within the normal range(< 20 μg/L) in 27.4%(n = 631) of all the cases.81.4%(n = 1875) patients were infected with HBV,and those patients had much higher serum AFP level compared with non-HBV infection ones(573.9 ± 547.7 μg/L vs 398.4 ± 522.3 μg/L,P < 0.001).The AFP level in tumors ≥ 10 cm(808.4 ± 529.2 μg/L) was significantly higher(P < 0.001) than those with tumor size 5-10 cm(499.5 ± 536.4 μg/L) and with tumor size ≤ 5 cm(444.9 ± 514.2 μg/L).AFP levels increased significantly in patients with vascular invasion(694.1 ± 546.9 μg/L vs 502.1 ± 543.1 μg/L,P < 0.001).Patients with low tumor cell differentiation(559.2 ± 545.7 μg/L) had the significantly(P = 0.007) highest AFP level compared with high differentiation(207.3 ± 420.8 μg/L) and intermediate differe     

Effect of interferon-γ and tumor necrosis factor-α on hepatitis B virus following lamivudine treatment

AIM: To evaluate anti-hepatitis B virus (HBV) activity and cytotoxicity of interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) following lamivudine treatment of HepG2.2.15 cells.METHODS: HepG2.2.15 cells were treated with 2 μmol/L lamivudine for 16 d (lamivudine group), cultured for 10 d, followed by 5 ng/mL TNF-α and 1000 U/mL IFN-γ for 6 d (cytokine group), or treated with 2 μmol/L lamivudine for 10 d followed by 5 ng/mL TNF-α and 1000 U/mL IFN-γ for 6 d (sequential group), or cultured without additions for 16 d (control group). Intracellular DNA was extracted from 3 × 10⁵ HepG2.2.15 cells from each group. The extracted DNA was further purified with mung bean nuclease to remove HBV relaxed circular DNA that may have remained. Both HBV covalently closed circular DNA (cccDNA) and HBV DNA were examined with real-time polymerase chain reaction. The titers of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) were quantified with enzyme-linked immunosorbent assay. Cell viability was measured with the cell counting kit-8 assay.RESULTS: Compared to lamivudine alone (22.63% ± 0.12%), both sequential (51.50% ± 0.17%, P = 0.034) and cytokine treatment (49.66% ± 0.06%, P = 0.041) showed a stronger inhibition of HBV cccDNA; the difference between the sequential and cytokine groups was not statistically significant (51.50% ± 0.17% vs 49.66% ± 0.06%, P = 0.88). The sequential group showed less inhibition of HBV DNA replication than the lamivudine group (67.47% ± 0.02% vs 82.48% ± 0.05%, P = 0.014); the difference between the sequential and cytokine groups was not statistically significant (67.47% ± 0.02% vs 57.45% ± 0.07%, P = 0.071). The levels of HBsAg and HBeAg were significantly decreased in the sequential treatment group compared to the other groups [HBsAg: 3.48 ± 0.04 (control), 3.09 ± 0.08 (lamivudine), 2.55 ± 0.13 (cytokine), 2.32 ± 0.08 (sequential), P = 0.042 for each between-group comparison; HBeAg: 3.48 ± 0.01 (control), 3.08 ± 0.08 (lamivudine), 2.57 ± 0.15 (cytokine), 2.34 ± 0.12 (sequential), P = 0.048 for each between-group comparison]. Cell viability in the cytokine group was reduced to 58.03% ± 8.03% compared with control cells (58.03% ± 8.03% vs 100%, P = 0.000). Lamivudine pretreatment significantly reduced IFN-γ + TNF-α-mediated toxicity of HepG2.2.15 cells [85.82% ± 5.43% (sequential) vs 58.03% ± 8.03% (cytokine), P = 0.002].CONCLUSION: Sequential treatment overcame the lower ability of lamivudine alone to inhibit cccDNA and precluded the aggressive cytotoxicity involving IFN-γ and TNF-α by decreasing the viral load.     

白假丝酵母菌临床菌株对氟康唑耐药性及其与CAP1基因相关性研究

目的 了解白假丝酵母菌临床菌株对氟康唑的耐药率以及氟康唑耐药与白假丝酵母菌CAP1基因相关性。方法 采用微量稀释法检测了245株白假丝酵母菌临床菌株对氟康唑的敏感性。采用实时荧光定量RT-PCR(qRT-PCR)和流式细胞术分别检测白假丝酵母菌CAP1基因mRNA(CAP1-mRNA)及其表达产物Cap1p。采用氟康唑浓度递增(4~64 μg/mL)的YPD培养液连续培养法了解氟康唑诱导白假丝酵母菌耐药性的作用,qRT-PCR和流式细胞术确定CAP1基因与氟康唑耐药性形成的关系。结果 134株白假丝酵母菌对氟康唑敏感(MIC≤8 μg/mL)、36株剂量依赖敏感(16~32 μg/mL)、75株耐药(≥64 μg/mL),耐药率为30.6%(75/245)。氟康唑耐药白假丝酵母菌株CAP1-mRNA和Cap1p表达水平均明显高于氟康唑敏感菌株(P<0.05)。氟康唑能诱导氟康唑敏感菌株产生耐药性(MIC≥64 μg/mL),其CAP1-mRNA和Cap1p表达水平也显著升高(P<0.05)。结论 白假丝酵母菌临床菌株对氟康唑有较高的耐药率。氟康唑能诱导氟康唑敏感白假丝酵母菌株产生耐药性。白假丝酵母菌对氟康唑耐药性与CAP1基因表达上调密切相关。     

Effects of α-mangostin on apoptosis induction of human colon cancer

AIM: To investigate the effect of α-mangostin on the growth and apoptosis induction of human colon cancer cells.METHODS: The three colorectal adenocarcinoma cell lines tested (COLO 205, MIP-101 and SW 620) were treated with α-mangostin to determine the effect on cell proliferation by MTT assay, cell morphology, chromatin condensation, cell cycle analysis, DNA fragmentation, phosphatidylserine exposure and changing of mitochondrial membrane potential. The molecular mechanisms of α-mangostin mediated apoptosis were further investigated by Western blotting analysis including activation of caspase cascade, cytochrome c release, Bax, Bid, p53 and Bcl-2 modifying factor.RESULTS: The highest inhibitory effect of α-mangostin on cell proliferation of COLO 205, MIP-101 and SW 620 were 9.74 ± 0.85 μg/mL, 11.35 ± 1.12 μg/mL and 19.6 ± 1.53 μg/mL, respectively. Further study showed that α-mangostin induced apoptotic cell death in COLO 205 cells as indicated by membrane blebbing, chromatin condensation, DNA fragmentation, cell cycle analysis, sub-G1 peak (P < 0.05) and phosphatidylserine exposure. The executioner caspase, caspase-3, the initiator caspase, caspase-8, and caspase-9 were expressed upon treatment with α-mangostin. Further studies of apoptotic proteins were determined by Western blotting analysis showing increased mitochondrial cytochrome c release, Bax, p53 and Bmf as well as reduced mitochondrial membrane potential (P < 0.05). In addition, up-regulation of tBid and Fas were evident upon treatment with α-mangostin (P < 0.01).CONCLUSION: α-Mangostin may be effective as an anti-cancer agent that induced apoptotic cell death in COLO 205 via a link between extrinsic and intrinsic pathways.     

Dihydromyricetin inhibits migration and invasion of hepatoma cells through regulation of MMP-9 expression

AIM:To investigate the effects of dihydromyricetin(DHM)on the migration and invasion of human hepatic cancer cells.METHODS:The hepatoma cell lines SK-Hep-1 and MHCC97L were used in this study.The cells were cultured in RPIM-1640 medium supplemented with 10%fetal bovine serum at 37℃in a humidified 5%CO2incubator.DHM was dissolved in dimethyl sulfoxide and diluted to various concentrations in medium before applying to cells.MTT assays were performed to measure the viability of the cells after DHM treatment.Wound healing and Boyden transwell assays were used to assess cancer cell motility.The invasive capacity of cancer cells was measured using Matrigel-coated transwell chambers.Matrix metalloproteinase(MMP)-2/9 activity was examined by fluorescence analysis.Western blot was carried out to analyze the expression of MMP-2,MMP-9,p-38,JNK,ERK1/2 and PKC-δproteins.All data were analyzed by Student’s t tests in GraphPad prism 5.0software and are presented as mean±SD.RESULTS:DHM was found to strongly inhibit the migration of the hepatoma cell lines SK-Hep-1(without DHM,24 h:120±8μmol/L vs 100μmol/L DHM,24h:65±10μmol/L,P<0.001)and MHCC97L(without DHM,24 h:126±7μmol/L vs 100μmol/L DHM,24h:74±6μmol/L,P<0.001).The invasive capacity of the cells was reduced by DHM treatment(SK-Hep-1cells without DHM,24 h:67±4μmol/L vs 100μmol/L DHM,24 h:9±3μmol/L,P<0.001;MHCC97L cells without DHM,24 h:117±8μmol/L vs 100μmol/L DHM,24 h:45±2μmol/L,P<0.001).MMP2/9 activity was also inhibited by DHM exposure(SK-Hep-1 cells without DHM,24 h:600±26μmol/L vs 100μmol/L DHM,24 h:100±6μmol/L,P<0.001;MHCC97L cells without DHM,24 h:504±32μmol/L vs 100μmol/L DHM 24 h:156±10μmol/L,P<0.001).Western blot analysis showed that DHM decreased the expression level of MMP-9 but had little effect on MMP-2.Further investigation indicated that DHM markedly reduced the phosphorylation levels of p38,ERK1/2 and JNK in a concentration-dependent manner but had no impact on the total protein levels.In addition,PKC-δprotein,a key protein in the regulation of MMP family protein expression,was up-regulated with DHM treatment.CONCLUSION:These findings demonstrate that DHM inhibits the migration and invasion of hepatoma cells and may serve as a potential candidate agent for the prevention of HCC metastasis.     

Antibiotic Susceptibility Profile of Helicobacter pylori Isolated from the Dyspepsia Patients in Tehran, Iran

Background/Aim:

Helicobacter pylori is an important pathogen for gastroduodenal diseases. Infection with H. pylori can be limited by regimens of multiple antimicrobial agents. However, antibiotic resistance is a leading cause of treatment failure. The aim of this study has been to determine the resistance patterns of H. pylori strains isolated from gastric biopsies of patients with dyspepsia by agar dilution method, in Tehran, Iran

Patients and Methods:

H. pylori isolates from patients with gastrointestinal diseases were evaluated for susceptibility testing by agar dilution method. Susceptibility testing was performed to commonly used antibiotics including clarithromycin, tetracycline, amoxicillin, metronidazole and ciprofloxacin.

Results:

Among 92 patients with dyspepsia, H. pylori strains were isolated from 42 patients. Seventeen (40.5%) of the isolates were resistant to metronidazole (MICs ≥ 8 μg/l), whereas one isolate (2.4%) was resistant to amoxicillin (MICs ≤ 0. 5 μg/ml) and ciprofloxacin (MICs ≤ 1μg/ml). The resistance rates to other antibiotics in H. pylori isolates are recorded as follows: clarithromycin 6 (14.3 %), tetracycline 2 (4.8%). In 5 of 42 resistant cases, combined resistance was found.

Conclusions:

These data suggest that metronidazole should be used among Iranian patients in first-line therapy with caution, and ciprofloxacin in association with amoxicillin and a proton pump inhibitor is more recommended.     

Anticancer effects of sweet potato protein on human colorectal cancer cells

AIM: To investigate the effects of proteins purified from sweet potato storage roots on human colorectal cancer cell lines. METHODS: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Hoechst 33258 nuclear staining and Boyden transwell chamber methods were used to determine whether purified sweet potato protein (SPP) from fresh sweet potato roots affected proliferation, migration and invasion, respectively, of human colorectal cancer SW480 cells in vitro . The inhibitory effects of SPP on growth of human colorectal cancer HCT-8 cells intraperitoneally xenografted in nude mice and spontaneous lung metastasis of murine Lewis lung carcinoma 3LL cells subcutaneously transplanted in C57 BL/6 mice were also investigated in vivo . RESULTS: SPP inhibited the proliferation of SW480 cells in a dose-dependent manner, with an IC 50 value of 38.732 μmol/L (r2 = 0.980, P = 0.003) in the MTT assay. Hoechst 33258 nuclear staining further revealed inhibition of cell viability and induction of apoptosis by SPP. The transwell assay disclosed significant reduction in migrated cells/field by 8 μmol/L SPP (8.4 ± 2.6 vs 23.3 ± 5.4, P = 0.031) and invaded cells/field through the ECMatrix by 0.8 μmol/L SPP, compared with the control (25.2 ± 5.2 vs 34.8 ± 6.1, P = 0.038). Both intraperitoneal (ip) and intragastric (ig) administration of SPP led to significant suppression of growth of intraperitoneally inoculated HCT-8 cells in nude mice to 58.0% ± 5.9% (P = 0.037) and 43.5% ± 7.1% (P = 0.004) of the controls, respectively, after 9 d treatment. Bloody ascites additionally disappeared after ip injection of trypsin inhibitor. Notably, ig and ip administration of SPP induced a significant decrease in spontaneous pulmonary metastatic nodule formation in C57 BL/6 mice (21.0 ± 12.3 and 27.3 ± 12.7 nodules/lung vs 42.5 ± 4.5 nodules/lung in controls, respectively, P < 0.05) after 25 d treatment. Moreover, the average weight of primary tumor nodules in the hind leg of mice decreased from 8.2 ± 1.3 g/mice in     

Construction of retroviral vectors to induce a strong expression of human class Ⅰ interferon gene in human hepatocellular carcinoma cells in vitro

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Effect of the ginsenoside Rb1 on the spontaneous contraction of intestinal smooth muscle in mice

AIM: To investigate the effect and the possible mechanism of ginsenoside Rb1 on small intestinal smooth muscle motility in mice. METHODS: Intestinal smooth muscle strips were isolated from male ICR mice (5 wk old), and the effect of ginsenoside Rb1 on spontaneous contraction was recorded with an electrophysiolograph. The effect of ginsenoside Rb1 on ion channel currents, including the voltage-gated K + channel current (IK V ), calcium-activated potassium channel currents (IK Ca ), spontaneous transient outward currents and ATP-sensitive potassium channel current (IK ATP ), was recorded on freshly isolated single cells using the whole-cell patch clamp technique. RESULTS: Ginsenoside Rb1 dose-dependently inhibited the spontaneous contraction of intestinal smooth muscle by 21.15% ± 3.31%, 42.03% ± 8.23% and 67.23% ± 5.63% at concentrations of 25 μmol/L, 50 μmol/L and 100 μmol/L, respectively (n=5,P0.05). The inhibitory effect of ginsenoside Rb1 on spontaneous contraction was significantly but incompletely blocked by 10 mmol/L tetraethylammonium or 0.5 mmol/L 4-aminopyridine, respectively (n=5, P0.05). However, the inhibitory effect of ginsenoside Rb1 on spontaneous contraction was not affected by 10 μmol/L glibenclamide or 0.4 μmol/L tetrodotoxin. At the cell level, ginsenoside Rb1 increased outward potassium currents, and IK V was enhanced from 1137.71 ± 171.62 pA to 1449.73 ± 162.39 pA by 50 μmol/L Rb1 at +60 mV (n=6, P0.05). Ginsenoside Rb1 increased IK Ca and enhanced the amplitudes of spontaneous transient outward currents from 582.77 ± 179.09 mV to 788.12 ± 278.34 mV (n=5, P0.05). However, ginsenoside Rb1 (50 μmol/L) had no significant effect on IK ATP (n=3, P0.05). CONCLUSION: These results suggest that ginsenoside Rb1 has an inhibitory effect on the spontaneous contraction of mouse intestinal smooth muscle mediated by the activation of IK V and IK Ca , but the K ATP channel was not involved in this effect.     

Cytokine-mediated expansion does not deplete cord blood cells with stem cell characteristics

Cord blood (CB) has been successfully used to regenerate the hematopoietic system after myeloablative therapy. We investigated whether cytokine mediated expansion depletes CB of cells with stem cell characteristics. CB mononuclear cells (MNC) were enriched for quiescent (primitive) stem cells by incubation with 25 μg/ml 5-Fluorouracil (5-FU) and control CB MNC were incubated with media alone. Cells were then incubated for 7 days with Interleukin-1 (IL1)+IL3+ Stem Cell Factor (SCF) and progenitor content, cell cycle status, nucleated cell count, immunophenotype and resistance to 25 μg/ml 5-FU (primitive stem cells) were evaluated before and after cytokine exposure. Incubation with IL1+IL3+SCF caused an increase (fold expansion) in committed (28.6 ± 8.1), immature (5.8 ± 1.8), and primitive progenitors (4.1 ± 0.8) among control CB MNC compared to a decrease in committed progenitors (0 ± 0) but an increase in both immature (8.4 ± 4.8) and primitive progenitors (7 ± 2.9) among 5-FU resistant CB MNC. An increase in the proportion of CD34⁺ cells occurred in both fractions. Expanded control CB MNC showed a significant increase in numbers of 5-FU resistant committed (p = 0.024), immature (p = 0.014) and primitive progenitors (p = 0.01) as compared with fresh CB MNC. Re-exposure of 5-FU resistant expanded CB MNC to 5-FU shows growth of some immature and primitive progenitors. Cytokine-mediated expansion of untreated and quiescent CB cells is possible and cytokine-mediated expansion does not deplete CB cells with stem cell characteristics.     

PI3K expression and PIK3CA mutations are related to colorectal cancer metastases

AIM: To assess the significance of phosphatidylinositol 3-kinase (PI3K) in colorectal cancer (CRC) and toxicity of {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002 in CRC cells with different metastatic abilities.METHODS: Sixty formalin-fixed and paraffin-embedded CRC tumor specimens were investigated. Adjacent normal colonic mucosa specimens from 10 of these cases were selected as controls. PI3K protein was detected by immunohistochemistry and PIK3CA mutations were investigated by gene sequencing analysis. A flow-cytometry-based apoptosis detection kit was used to determine PI3K inhibitor-induced apoptosis in CRC cell lines SW480 and SW620. Expression of phosphorylated protein kinase B in CRC cell lines was detected by Western blotting.RESULTS: There was a significant difference in the proportion of primary lesions (30%, 18/60) vs metastatic lesions (46.7%, 28/60) that were positive for PI3K (P < 0.05). Mutations were detected in exon 9 (13.3%) and exon 20 (8.3%). Out of 60 cases, seven mutations were identified: two hotspot mutations, C.1633G>A resulting in E545A, and C.3140A>G resulting in H1047R; two novel missense mutations C.1624G>A and C.3079G>A; and three synonymous mutations (C.1641G>A, C.1581C>T and C.3027T>A). Exposure of SW480 cells to PI3K inhibitor for 48 h resulted in a significant increase of apoptotic cells in a dose-dependent manner [3.2% apoptotic cells in 0 μmol/L, 4.3% in 5 μmol/L, 6.3% in 10 μmol/L (P < 0.05), and 6.7% in 20 μmol/L (P < 0.05)]. Moreover, PI3K inhibitor induced a similar significant increase of apoptotic cells in the SW620 cell line for 48 h [3.3% apoptotic cells in 0 μmol/L, 13.3% in 5 μmol/L (P < 0.01), 19.2% in 10 μmol/L (P < 0.01), and 21.3% in 20 μmol/L (P < 0.01)].CONCLUSION: High PI3K expression is associated with CRC metastasis. PI3K inhibitor induced apoptosis in CRC cells and displayed strong cytotoxicity for highly metastatic cells. PI3K inhibition may be an effective treatment for CRC.