NKD1 promotes glucose uptake in colon cancer cells by activating YWHAE transcription / 南方医科大学学报

OBJECTIVE@#Bo investigate the regulatory relationship between NKD1 and YWHAE and the mechanism of NKD1 for promoting tumor cell proliferation.@*METHODS@#HCT116 cells transfected with pcDNA3.0-NKD1 plasmid, SW620 cells transfected with NKD1 siRNA, HCT116 cells with stable NKD1 overexpression (HCT116-NKD1 cells), SW620 cells with nkd1knockout (SW620-nkd1-/- cells), and SW620-nkd1-/- cells transfected with pcDNA3.0-YWHAE plasmid were examined for changes in mRNA and protein expression levels of YWHAE using qRT-PCR and Western blotting. Chromatin immunoprecipitation (ChIP) assay was used to detect the binding of NKD1 to the promoter region of YWHAE gene. The regulatory effect of NKD1 on YWHAE gene promoter activity was analyzed by dual-luciferase reporter gene assay, and the interaction between NKD1 and YWHAE was analyzed with immunofluorescence assay. The regulatory effect of NKD1 on glucose uptake was examined in the tumor cells.@*RESULTS@#In HCT116 cells, overexpression of NKD1 significantly enhanced the expression of YWHAE at both the mRNA and protein levels, while NKD1 knockout decreased its expression in SW620 cells (P < 0.001). ChIP assay showed that NKD1 protein was capable of binding to the YWHAE promoter sequence; dual luciferase reporter gene assay showed that NKD1 overexpression (or knockdown) in the colon cancer cells significantly enhanced (or reduced) the transcriptional activity of YWHAE promoter (P < 0.05). Immunofluorescence assay demonstrated the binding of NKD1 and YWHAE proteins in colon cancer cells. NKD1 knockout significantly reduced glucose uptake in colon cancer cells (P < 0.01), while YWHAE overexpression restored the glucose uptake in NKD1-knockout cells (P < 0.05).@*CONCLUSION@#NKD1 protein activates the transcriptional activity of YWHAE gene to promote glucose uptake in colon cancer cells.

Construction of a stable TrxR1 knockout HCT-116 cell line using CRISPR/Cas9 gene editing system / 生物工程学报

To investigate the cellular target selectivity of small molecules targeting thioredoxin reductase 1, we reported the construction and functional research of a stable TrxR1 gene (encode thioredoxin reductase 1) knockout HCT-116 cell line. We designed and selected TrxR1 knockout sites according to the TrxR1 gene sequence and CRISPR/Cas9 target designing principles. SgRNA oligos based on the selected TrxR1 knockout sites were obtained. Next, we constructed knockout plasmid by cloning the sgRNA into the pCasCMV-Puro-U6 vector. After transfection of the plasmid into HCT-116 cells, TrxR1 knockout HCT-116 cells were selected using puromycin resistance. The TrxR1 knockout efficiency was identified and verified by DNA sequencing, immunoblotting, TRFS-green fluorescent probe, and cellular TrxR1 enzyme activity detection. Finally, the correlation between TrxR1 expression and cellular effects of drugs specifically targeting TrxR1 was investigated by CCK-8 assay. The results demonstrated that the knockout plasmid expressing the sgRNA effectively knocked-out TrxR1 gene within HCT-116 cells, and no expression of TrxR1 protein could be observed in stable TrxR1 knockout HCT-116 (HCT116-TrxR1-KO) cells. The TrxR1-targeting inhibitor auranofin did not show any inhibitory activity against either cellular TrxR1 enzyme activity or cell proliferation. Based on these results, we conclude that a stable TrxR1 gene knockout HCT-116 cell line was obtained through CRISPR/Cas9 techniques, which may facilitate investigating the role of TrxR1 in various diseases.

Nanostructured lipid carriers as a novel tool to deliver sclareol: physicochemical characterisation and evaluation in human cancer cell lines

Sclareol (SC) is arousing great interest due to its cytostatic and cytotoxic activities in several cancer cell lines. However, its hydrophobicity is a limiting factor for its in vivo administration. One way to solve this problem is through nanoencapsulation. Therefore, solid lipid nanoparticles (SLN-SC) and nanostructured lipid carriers (NLC-SC) loaded with SC were produced and compared regarding their physicochemical properties. NLC-SC showed better SC encapsulation than SLN-SC and was chosen to be compared with free SC in human cancer cell lines (MDA-MB-231 and HCT-116). Free SC had slightly higher cytotoxicity than NLC-SC and produced subdiploid DNA content in both cell lines. On the other hand, NLC-SC led to subdiploid content in MDA-MB-231 cells and G2/M checkpoint arrest in HCT-116 cells. These findings suggest that SC encapsulation in NLC is a way to allow the in vivo administration of SC and might alter its biological properties

Inhibition effect of active fraction from clove on PI3K/Akt/mTOR signaling pathway to induce apoptosis of human colon cancer HCT116 cells / 中国中药杂志

To screen the sensitive cell lines of active fraction from clove(AFC) on human colon cancer cells, investigate the effects of AFC on the cells proliferation and apoptosis as well as PI3 K/Akt/mTOR(phosphoinositide 3-kinase/Akt/mechanistic target of rapamycin) signaling pathways involved, and reveal the mechanism of AFC for inducing apoptosis of human colorectal carcinoma cells. Cell counting kit-8(CCK-8) assay was used to detect the cytotoxic effect of different concentrations of AFC. AFC-induced apoptosis was detected by Hoechst 33258 fluorescence staining and Annexin V-FITC/PI double staining. HCT116 cells were treated with AFC with or without pretreatment with insulin-like growth factor-Ⅰ(IGF-Ⅰ), and then the protein expression levels of caspase-3, caspase-9, poly ADP-ribose polymerase(PARP), PI3 K, p-PI3 K, Akt, p-Akt, mTOR and p-mTOR in PI3 K/Akt/mTOR signaling pathway were detected by Western blot. RESULTS:: showed that the most obvious inhibitory effect of AFC was on human colon cancer HCT116 cells, and the optimal AFC treatment time was 48 hours. After AFC treatment, typical apoptotic features such as nuclear chromatin concentration, nuclear fragmentation and apoptotic bodies appeared in a dose-dependent manner. Annexin V-FITC/PI double staining showed that as compared with the control group, 50 and 100 μg·mL~(-1) AFC groups increased the apoptosis rate of HCT116 cells significantly(P<0.001); AFC activated caspase-9, cleaved caspase-3 and cleaved PARP in a concentration-dependent manner. The protein expression levels of cleaved caspase-3/procaspase-3, cleaved PARP/PARP and caspase-9/β-actin after treatment of AFC(100 μg·mL~(-1)) were significantly different from those in the control group(P<0.001). The relative protein expression of p-PI3 K, p-Akt and p-mTOR decreased in a concentration dependent manner, while Akt and mTOR showed no significant differences among groups. The ratios of p-PI3 K/PI3 K, p-Akt/Akt and p-mTOR/mTOR in the AFC groups(50 and 100 μg·mL~(-1)) were significantly lower than those in the control group(P<0.01). Its combination with IGF-Ⅰ weakened the effect of AFC in inhibiting PI3 K/Akt/mTOR signaling pathway. The ratios of p-Akt/Akt and p-mTOR/mTOR in the AFC+IGF-Ⅰ group were significantly enhanced as compared with the AFC group(P<0.05). Apoptosis-related protein expression levels(cleaved caspase-3 and cleaved PARP) in HCT116 cells treated with AFC+IGF-Ⅰ were also down regulated. As compared with the AFC group, the ratios of cleaved caspase-3/procaspase-3 and cleaved PARP/PARP in the AFC+IGF-Ⅰ group were significantly decreased(P<0.01). In summary, AFC activated caspase-mediated cascades and induced HCT116 cells apoptosis in a dose-dependent manner, which may be associated with the inhibition of the PI3 K/Akt/mTOR signaling pathway.

Antioxidant and growth inhibitory activities of Mesembryanthemum crystallinum L. in HCT116 human colon cancer cells / 한국영양학회지

PURPOSE: This study examined the antioxidant and cancer cell growth inhibitory activities of an ethanol extract and different solvent fractions of Mesembryanthemum crystallinum L. (ice plant). METHODS: The ice plant was freeze-dried, extracted with 99.9% ethanol, and then fractionated with hexane, ethyl acetate, butanol, and water. The total polyphenol content (TPC), total carotenoid content (TCC), 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity (RSA), and ferric reducing antioxidant power (FRAP) were measured. Assays using 2′,7′-dichlorofluorescin-diacetate and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide were performed to measure the intracellular reactive oxygen species (ROS) and cell growth, respectively. Annexin V/propidium iodide staining and cell cycle analysis were performed for the detection of apoptosis and cell cycle arrest. RESULTS: TPC, TCC, RSA, and FRAP of the ethanol extract (EE) were 3.7 mg gallic acid equivalent/g, 13.2 µg/g, 21.0% (at a concentration of 5 mg/mL), and 21.0% (at a concentration of 5 mg/mL), respectively. Among the different solvent fractions, the butanol fraction (BF) showed the highest TPC (5.4 mg gallic acid equivalent/g), TCC (86.6 µg/g), RSA (34.9% at 5 mg/mL), and FRAP (80.8% at 5 mg/mL). Treatment of HCT116 human colon cancer cells with EE and BF at concentrations of 250 and 500 µg/mL reduced the levels of intracellular ROS. Concomitantly, EE and BF resulted in the dose-dependent inhibition of cell growth (at the concentrations of 125, 250, and 500 µg/mL for 24 ~ 48 h) and the induction of apoptosis (at the concentrations of 250 and 500 µg/mL for 48 h) in HCT116 cells. An increased G2/M cell population was also found in the BF-treated cells. CONCLUSION: These results suggest that ice plant possesses antioxidant and growth inhibitory activities in colon cancer cells.

15-Deoxy-Δ(12,14)-prostaglandin J₂ Upregulates the Expression of 15-Hydroxyprostaglandin Dehydrogenase by Inducing AP-1 Activation and Heme Oxygenase-1 Expression in Human Colon Cancer Cells

BACKGROUND: Abnormal upregulation of prostaglandin E₂ (PGE₂) is considered to be a key oncogenic event in the development and progression of inflammation-associated human colon cancer. It has been reported that 15-hydroxyprostaglandin dehydrogenase (15-PGDH), an enzyme catabolizing PGE₂, is ubiquitously downregulated in human colon cancer. 15-Deoxy-Δ(12,14)-prostaglandin J₂ (15d-PGJ₂), a peroxisome proliferator-activated receptor γ ligand, has been shown to have anticarcinogenic activities. In this study, we investigate the effect of 15d-PGJ₂ on expression of 15-PGDH in human colon cancer HCT116 cells. METHODS: HCT116 cells were treated with 15d-PGJ₂ analysis. The expression of 15-PGDH in the treated cells was measured by Western blot analysis and RT-PCR. In addition, the cells were subjected to a 15-PGDH activity assay. To determine which transcription factor(s) and signaling pathway(s) are involved in 15d-PGJ₂-induced 15-PGDH expression, we performed a cDNA microarray analysis of 15d-PGJ₂-treated cells. The DNA binding activity of AP-1 was measured by an electrophoretic mobility shift assay. To determine whether the AP-1 plays an important role in the 15d-PGJ₂-induced 15-PGDH expression, the cells were transfected with siRNA of c-Jun, a major subunit of AP-1. To elucidate the upstream signaling pathways involved in AP-1 activation by 15d-PGJ₂, we examined its effect on phosphorylation of Akt by Western blot analysis in the presence or absence of kinase inhibitor. RESULTS: 15d-PGJ₂ (10 μM) significantly upregulated 15-PGDH expression at the mRNA and protein levels in HCT-116 cells. 15-PGDH activity was also elevated by 15d-PGJ₂. We observed that genes encoding C/EBP delta, FOS-like antigen 1, c-Jun, and heme oxygenase-1 (HO-1) were most highly induced in the HCT116 cells following 15d-PGJ₂ treatment. 15d-PGJ₂ increased the DNA binding activity of AP-1. Moreover, transfection with specific siRNA against c-Jun significantly reduced 15-PGDH expression induced by 15d-PGJ₂. 15d-PGJ₂ activates Akt and a pharmacological inhibitor of Akt, LY294002, abrogated 15d-PGJ₂-induced 15-PGDH expression. We also observed that an inhibitor of HO-1, zinc protoporphyrin IX, also abrogated upregulation of 15-PGDH and down-regulation of cyclooxygenase-2 expression induced by 15d-PGJ₂. CONCLUSIONS: These finding suggest that 15d-PGJ₂ upregulates the expression of 15-PGDH through AP-1 activation in colon cancer HCT116 cells.

Cytotoxic activity of extract and active fraction of Turbinaria decurrens Bory on colon cancer cell line HCT-116 / Actividad citotóxica del extracto y la fracción activa de Turbinaria decurrens Bory en la línea celular de cáncer de colon HCT-116

Turbinaria deccurrens Bory contains bioactive compound that is beneficial for health. Turbinaria deccurrens Bory is one of many species of brown seaweed that grows in Indonesian marine life and has been known to have cytotoxic activity. The aim of this study is to determine fucoxantin content and the cytotoxic activity of extract and fraction T. decurrens on colon cancer cell lines. Cytotoxic assay of ethanolic extract, n-hexane, ethyl acetate and ethanolic fractions against HCT-116 by MTS assay using Cell Counting Kit-8 (CCK-8). Fucoxantin content in extract and fraction were analyzed using Reversed-Phase High Performance Liquid Chromatography (RP-HPLC) analysis. Extract and fraction of T. decurrens contain fucoxanthin with the highest content of fucoxanthin was in ethyl acetate fraction. CCK-8 assay showed that extract, n-hexane and ethyl acetate fraction inhibited the growth of HCT-116. Brown seaweed Turbinaria decurrens was potential as an anticolon cancer agent.

Turbinaria deccurrens Bory contiene compuestos bioactivos que son beneficiosos para la salud. Turbinaria deccurrens Bory es una de muchas especies de algas pardas que crecen en aguas marinas de Indonesia y se ha estudiado su actividad citotóxica. El objetivo de este estudio fue determinar el contenido de fucoxantina y la actividad citotóxica del extracto y la fracción de T. decurrens en líneas celulares de cáncer de colon. Se llevó a cabo un ensayo citotóxico de extracto etanólico, nhexano, acetato de etilo y fracciones etanólicas contra HCT-116 mediante ensayo MTS utilizando Cell Counting Kit-8 (CCK-8). El contenido de fucoxantina en el extracto y la fracción se analizaron usando cromatografía líquida de alta resolución de fase reversa (RP-HPLC). El extracto y la fracción de T. decurrens contienen fucoxantina conmayor contenido de fucoxantina en la fracción de acetato de etilo. El ensayo CCK-8 mostró que la fracción de extracto, n-hexano y acetato de etilo inhibía el crecimiento de HCT-116. El alga marrón Turbinaria decurrens es un agente potencial contra el cáncer de colon.

Icariin reduces human colon carcinoma cell growth and metastasis by enhancing p53 activities

Icariin has been reported to possess high anticancer activity. Colon carcinoma is one of the leading causes of cancer-related mortality worldwide. Here, the anticancer activity of icariin against HCT116 colon carcinoma cells and the possible underlying mechanism were studied. The trypan blue staining assay, wound healing assay, clonogenic assay, CCK-8 assay, and Annexin V-FITC/PI double staining method were carried out to determine the changes of HCT116 cell growth and migration. mRNA and protein expressions were determined by quantitative real-time PCR and western blot, respectively. Moreover, small interfering RNA (siRNA) plasmid was used to examine the role of p53 in icariin-induced apoptosis in HCT116 cells. Icariin significantly suppressed colon carcinoma HCT116 cells by decreasing migration and viability, and simultaneously promoting apoptosis. Icariin exerted the anti-tumor effect in a dose-dependent manner by up-regulating p53. During treatment of icariin, p-p53, p21, and Bax levels increased, and Bcl-2 level decreased. Short time treatment with icariin induced DNA damage in HCT116 cells. Furthermore, the cytotoxicity of icariin was decreased after p53 knockdown or by using caspase inhibitors. p53 was involved in activities of caspase-9 and caspase-3. Icariin repressed colon carcinoma cell line HCT116 by enhancing p53 expression and activating p53 functions possibly through Bcl-2/Bax imbalance and caspase-9 and -3 regulation. Icariin treatment also induced DNA damage in HCT116 cells.

The NK1 receptor antagonist NKP608 inhibits proliferation of human colorectal cancer cells via Wnt signaling pathway

BACKGROUND: Neurokinin1 (NK1) receptor has played a vital role in the development of tumor. However, NKP608 as a NK1 receptor antagonist whether has the effect of the resistance of colorectal cancer is still unclear. Thereby, in this study, we investigated the role of NKP608 on human colorectal cancer and explored the underlying mechanism. METHODS: The cell proliferation of colorectal cancer cells was detected by cell counting kit-8 (CCK8) assay, cell migration and invasion were assessed by transwell assay, the apoptotic ratio of cells was assessed by Annexin V-fluorescein isothiocyanate/propidium iodide stained and flow cytometry. The involvement of molecular mechanisms was examined by western blot. RESULTS: In this study, we found that NKP608 inhibited the proliferation, migration/invasion of HCT116 cells. In addition, NKP608 reduced expressions of Wnt-3a, ß-catenin, Cyclin D1, and (vascular endothelial growth factor) VEGF while induced expression of E-Cadherin. Furthermore, flow cytometry analyzed that NKP608 induced apoptosis of HCT116 cells, consistently, western blotting detecting of apoptosis-related proteins revealed that NKP608 downregulated Bcl-2 while upregulated Bax and Active-Caspase-3. CONCLUSIONS: Taken together, our results demonstrated that NKP608 inhibited colorectal cancer cell proliferation, migration and invasion via suppressing the Wnt/ß-catenin signaling pathway. Therefore, NKP608 might represent a promising therapeutic agent in the treatment of colorectal cancer.

Ferroptosis: A Novel Anti-tumor Action for Cisplatin / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Ferroptosis is a new mode of regulated cell death, which is completely distinct from other cell death modes based on morphological, biochemical, and genetic criteria. This study evaluated the therapeutic role of ferroptosis in classic chemotherapy drugs, including the underlying mechanism. MATERIALS AND METHODS: Cell viabilitywas detected by using the methylthiazoltetrazlium dye uptake method. RNAiwas used to knockout iron-responsive element binding protein 2, and polymerase chain reaction, western blot was used to evaluate the efficiency. Intracellular reduced glutathione level and glutathione peroxidases activitywere determined by related assay kit. Intracellularreactive oxygen species levelswere determined by flowcytometry. Electron microscopywas used to observe ultrastructure changes in cell. RESULTS: Among five chemotherapeutic drugs screened in this study, cisplatin was found to be an inducer for both ferroptosis and apoptosis in A549 and HCT116 cells. The depletion of reduced glutathione caused by cisplatin and the inactivation of glutathione peroxidase played the vital role in the underlying mechanism. Besides, combination therapy of cisplatin and erastin showed significant synergistic effect on their anti-tumor activity. CONCLUSION: Ferroptosis had great potential to become a new approach in anti-tumor therapies and make up for some classic drugs, which open up a new way for their utility in clinic.

Expression of secreted frizzled-related protein 4 in DNA mismatch repair-deficient and mismatch repair-proficient colorectal cancers / 南方医科大学学报

OBJECTIVE@#To investigate the expressions of secreted frizzled-related protein 4 (SFRP4) in stage Ⅱ DNA mismatch repair-deficient (dMMR) and mismatch repair- proficient (pMMR) colorectal cancers and explore their clinical significance.@*METHODS@#We collected fresh stage Ⅱ colon cancer tissues with different MMR status detected by immunohistochemistry (IHC). The differentially expressed mRNAs between dMMR and pMMR tumors were identified by Affymetrix Human oeLncRNA gene chip, and the expression of SFRP4 in these cancer tissues and in colorectal cancer cell lines were detected using Western blotting and real- time quantitative PCR. The apoptosis rates of HCT116 cells with and without siRNA- mediated transient SFRP4 knockdown were determined using flow cytometry. We further investigated the expression pattern of Ki-67 and its correlation with SFRP4 expression.@*RESULTS@#Compared with pMMR colon cancer tissues or cells, both dMMR colon cancer tissues (=0.014) and cells (=0.0079) showed significantly increased expression of SFRP4, which was in negative correlation with Ki-67 (=0.041). In HCT116 cells, transient SFRP4 knockdown resulted in decreased cell apoptosis, including both early apoptosis (=0.003) and late apoptosis (=0.024).@*CONCLUSIONS@#Up-regulation of SFRP4 in dMMR stage Ⅱ colon cancer promotes apoptosis and inhibits proliferation of the cancer cells, and may improve the prognosis of dMMR colon cancer.

MicroRNA-455 suppresses the oncogenic function of HDAC2 in human colorectal cancer

Colorectal cancer (CRC) is the fourth leading cause of cancer-induced mortality. Histone deacetylase 2 (HDAC2) is involved in prognosis and therapy of CRC. This study aimed to explore novel therapeutic targets for CRC. The alteration of HDAC2 expression in CRC tissues was estimated by qRT-PCR. After lentivirus transfection, HDAC2 knockdown was confirmed by western blot analysis. The effect of HDAC2 knockdown on cell proliferation was then assessed by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Screened by TargetScan, microRNA (miR)-455 was predicted to bind to 3′UTR of HDAC2 and the prediction was verified by luciferase assay. Finally, cells were transfected, respectively, with miR-455 mimics or miR-455 negative control (miR-NC) and the expression of HDAC2, cell proliferation and apoptosis of transfected cells were respectively evaluated by western blot analysis, MTT assay and flow cytometry. Results showed that the HDAC2 expression was up-regulated in CRC tissues (P<0.05). HDAC2 knockdown significantly decreased cell viability at day 3 (P<0.05), day 4 (P<0.01), and day 5 (P<0.001) after infection. Then, miR-455 was verified to directly target HDAC2, resulting in a significant difference in luciferase activity (P<0.01). Moreover, miR-455 decreased the expression of HDAC2 (P<0.01). miR-455 remarkably decreased cell viability at day 3 (P<0.05), day 4 (P<0.01), and day 5 (P<0.001) after transfection while inducing cell apoptosis (P<0.001). In conclusion, miR-455 inhibited cell proliferation while inducing cell apoptosis by targeting HDAC2 in CRC cells.

Mesua ferrea stem bark extract induces apoptosis and inhibits metastasis in human colorectal carcinoma HCT 116 cells, through modulation of multiple cell signalling pathways / 中国天然药物

Considering the great potential of natural products as anticancer agents, the present study was designed to explore the molecular mechanisms responsible for anticancer activities of Mesua ferrea stem bark extract against human colorectal carcinoma. Based on MTT assay results, bioactive sub-fraction (SF-3) was selected for further studies using HCT 116 cells. Repeated column chromatography resulted in isolation of less active α-amyrin from SF-3, which was identified and characterized by GC-MS and HPLC methods. α-amyrin and betulinic acid contents of SF-3 were measured by HPLC methods. Fluorescent assays revealed characteristic apoptotic features, including cell shrinkage, nuclear condensation, and marked decrease in mitochondrial membrane potential in SF-3 treated cells. In addition, increased levels of caspases-9 and -3/7 levels were also observed in SF-3 treated cells. SF-3 showed promising antimetastatic properties in multiple in vitro assays. Multi-pathway analysis revealed significant down-regulation of WNT, HIF-1α, and EGFR with simultaneous up-regulation of p53, Myc/Max, and TGF-β signalling pathways in SF-3 treated cells. In addition, promising growth inhibitory effects were observed in SF-3 treated HCT 116 tumour spheroids, which give a hint about in vivo antitumor efficacy of SF-3 phytoconstituents. In conclusion, these results demonstrated that anticancer effects of SF-3 towards colon cancer are through modulation of multiple molecular pathways.

MiR-145 inhibits drug resistance to Oxaliplatin in colorectal cancer cells through regulating G protein coupled receptor 98 / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To predict and identify the target gene of miR-145, and to explore the underlying mechanism of the inhibition of miR-145 on drug resistance to Oxaliplatin (L-OHP) in human colorectal cancer cells.</p><p><b>METHODS</b>L-OHP-resistant human colorectal cancer cell line (HCT116/L-OHP) was established in vitro by exposing to increased concentrations of L-OHP in cell culture medium. MiR-145-mimics and its negative control (NC-miRNA) were transfected into HCT116/L-OHP cells using liposome to establish HCT116/L-OHPover-expressing miR-145 and HCT116/L-OHP. The target genes of miR-145 were predicted by bioinformatic analysis, and validated by dual luciferase activity assay. After determination of G protein coupled receptor 98(GPR98) as target gene, corresponding plasmids were constructed and transfected to establish HCT116/L-OHPover-expressing GPR98 and HCT116/L-OHP. HCT116/L-OHP cells over-expressing both GPR98 and miR-145 (HCT116/L-OHP) were acquired through modification of the binding sites of GPR98 cDNA with miR-145. CCK-8 assay was used to assess the proliferation (A value) and sensitivity to L-OHP (the lower the IC50, the stronger the sensitivity) in HCT116/L-OHP cells. Real-time quantitative PCR was used to measure the mRNA expression of miR-145 and GPR98. Western blot was used to examine the protein expression of GPR98 and drug-resistant associated protein, such as P-glycoprotein (gp), multiple drug-resistance protein 1(MRP1), cancer-inhibition gene PTEN.</p><p><b>RESULTS</b>HCT116/L-OHP cell line was successfully established with ICof (42.34±1.05) mg/L and miR-145 mRNA expression of 0.27±0.04, which was higher than (9.81±0.95) mg/L (t=39.784, P=0.000) and lower than 1.00±0.09 (t=13.021, P=0.000) in HCT116 cells. Based on HCT116/L-OHP cells, HCT116/L-OHPcells were established successfully, with relative miR-145 expression of 10.01±1.05, which was higher than 1.06±0.14 in HCT116/L-OHPand 1.00±0.16 in HCT116/L-OHP (F=161.797, P=0.000). GPR98 was identified to be the target gene of miR-145. The relative mRNA and protein expressions of GPR98 in HCT116/L-OHPcells were 8.48±0.46 and 1.71±0.09, respectively, which were higher than those in HCT116/L-OHP(mRNA: 3.65±0.40, protein: 1.21±0.10) and HCT116/L-OHP (mRNA: 3.49±0.35, protein: 1.22±0.08; all P<0.05). The A value was 1.31±0.10, and the relative protein expressions of P-gp and MRP1 were 1.53±0.18 and 1.49±0.20 in HCT116/L-OHPcells, which were higher than those in HCT116/L-OHP (A value: 0.82±0.08, relative protein expression: 1.00±0.06 and 1.21±0.13, all P<0.05). The A value was 0.89±0.08, and the relative protein expressions of P-gp and MRP were 1.02±0.24 and 1.38±0.25 in HCT116/L-OHPcells, which were higher than those in HCT116/L-OHP(A value: 0.20±0.05, relative protein expression: 0.20±0.07, 0.55±0.10, all P<0.05). The relative protein expression of PTEN in HCT116/L-OHPcells was 0.12±0.03, which was lower than 1.25±0.14 in HCT116/L-OHP cells(P<0.05). In addition, relative protein expressions of P-gp and MRP1 were 1.02±0.24 and 1.38±0.25 in HCT116/L-OHPcells, which were higher than those in HCT116/L-OHPcells (0.20±0.07 and 0.55±0.10), while PTEN expression in HCT116/L-OHPcells was lower as compared to HCT116/L-OHPcells (1.41±0.16 vs. 1.98±0.13, P<0.05).</p><p><b>CONCLUSION</b>MiR-145 inhibits drug resistance to L-OHP of HCT116 cells through suppressing the expression of target gene GPR98.</p>

The oncogenic effects of p53-inducible gene 3 (PIG3) in colon cancer cells

The p53-inducible gene 3 (PIG3), initially identified as a gene downstream of p53, plays an important role in the apoptotic process triggered by p53-mediated reactive oxygen species (ROS) production. Recently, several studies have suggested that PIG3 may play a role in various types of cancer. However, the functional significance of PIG3 in cancer remains unclear. Here, we found that PIG3 was highly expressed in human colon cancer cell lines compared to normal colonderived fibroblasts. Therefore, we attempted to elucidate the functional role of PIG3 in colon cancer. PIG3 overexpression increases the colony formation, migration and invasion ability of HCT116 colon cancer cells. Conversely, these tumorigenic abilities were significantly decreased in in vitro studies with PIG3 knockdown HCT116 cells. PIG3 knockdown also attenuated the growth of mouse xenograft tumors. These results demonstrate that PIG3 is associated with the tumorigenic potential of cancer cells, both in vitro and in vivo, and could play a key oncogenic role in colon cancer.

PIG3 Regulates p53 Stability by Suppressing Its MDM2-Mediated Ubiquitination

Under normal, non-stressed conditions, intracellular p53 is continually ubiquitinated by MDM2 and targeted for degradation. However, in response to severe genotoxic stress, p53 protein levels are markedly increased and apoptotic cell death is triggered. Inhibiting the ubiquitination of p53 under conditions where DNA damage has occurred is therefore crucial for preventing the development of cancer, because if cells with severely damaged genomes are not removed from the population, uncontrolled growth can result. However, questions remain about the cellular mechanisms underlying the regulation of p53 stability. In this study, we show that p53-inducible gene 3 (PIG3), which is a transcriptional target of p53, regulates p53 stability. Overexpression of PIG3 stabilized both endogenous and transfected wild-type p53, whereas a knockdown of PIG3 lead to a reduction in both endogenous and UV-induced p53 levels in p53-proficient human cancer cells. Using both in vivo and in vitro ubiquitination assays, we found that PIG3 suppressed both ubiquitination- and MDM2-dependent proteasomal degradation of p53. Notably, we demonstrate that PIG3 interacts directly with MDM2 and promoted MDM2 ubiquitination. Moreover, elimination of endogenous PIG3 in p53-proficient HCT116 cells decreased p53 phosphorylation in response to UV irradiation. These results suggest an important role for PIG3 in regulating intracellular p53 levels through the inhibition of p53 ubiquitination.

Long non-coding RNA AFAP1-AS1 facilitates tumor growth and promotes metastasis in colorectal cancer

BACKGROUND AND OBJECTIVE: Long non-coding RNAs can regulate tumorigenesis of various cancers. Dys-regulation of lncRNA-AFAP1-AS1 has not been studied in colorectal carcinoma (CRC). This study was to examine the function involvement of AFAP1-AS1 in tumor growth and metastasis of CRC. METHODS: Relative expression of AFAP1-AS1 in CRC tissues and CRC cells lines was determined using quantitative real-time PCR (qRT-PCR). Functional involvement of AFAP1-AS1 in tumor proliferation and metastasis was evaluated in AFAP1-AS1-specific siRNA-treated CRC cells and in CRC cell xenograft. Expression of epithelial-mesenchymal transition (EMT)-related gene expression was determined using western blot. RESULTS: Relative expression of AFAP1-AS1 was significantly elevated in CRC tissues and CRC HCT116 and SW480 cell lines. AFAP1-AS1 knock-down suppressed SW480 cell proliferation, colony formation, migration and invasion. Also AFAP1-AS1 knock-down inhibited tumor metastasis-associated genes expression in terms of EMT. This carcinostatic action by AFAP1-AS1 knock-down was further confirmed by suppression of tumor formation and hepatic metastasis of CRC cells in nude mice. CONCLUSION: lncRNA-AFAP1-AS1 knock-down exhibits antitumor effect on colorectal carcinoma in respects of suppression of cell proliferation and metastasis of cancer cells.

ID1 suppress the apoptosis of HCT116 cells induced by chemotherapeutic drugs and ultraviolet radiation / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the changes of ID1 expression in tumor cells treated with etoposide, cisplatin and ultraviolet (UV) irradiation, and explore the effect of ID1 on chemotherapeutic drug- and UV-induced apoptosis.</p><p><b>METHODS</b>In the present study, upon onset of apoptosis induced by various kinds of inducers such as etoposide, cisplatin and UV irradiation, the expression level of ID1 was detected by Western blot and real-time PCR. We also analyzed the half-life of ID1 protein and stability of ID1 mRNA respectively by cycloheximide inhibition test and RT-PCR. Annexin-V assay was carried out to evaluate the contribution of ID1 protein to chemotherapeutic drug- and UV-induced apoptosis.</p><p><b>RESULTS</b>ID1 expression presented a profound down-regulation in the HCT116 cells treated with etoposide, cisplatin and UV irradiation(P<0.05 for all). The apoptosis in the UV irradiation group, cisplatin group, etoposide group was (58.70±1.55)%, (35.80±0.92)% and (21.00±0.72)%, respectively, significantly higher than that of the control group(1.10±0.07)%, (1.20±0.13)% and (3.50±0.23)% (P<0.05 for all). Upon etoposide treatment, ID1 expression level was decreased via induction of mRNA instability, but not the protein degradation changes. Additionally, ectopic expression of ID1 in the HCT116 cells alleviated etoposide-, cisplatin- and UV-induced apoptosis. The results of flow eytometry revealed that the percentage of apoptotic cells in the ID1 group under the treatment of etoposide, cisplatin and UV irradiation was (23.80±0.82)%, (17.80±1.34)% and (13.40±0.53)%, respectively, significantly lower than that in the empty vector group (41.10±1.61)%, (30.40±2.67)% and (22.50±3.47)% (P<0.05 for all).</p><p><b>CONCLUSIONS</b>These observations indicate that the treatment with etoposide reduces the amount of ID1 by induction of mRNA instability, and exogenously introduced ID1 protects cells against etoposide-, cisplatin- and UV irradiation-induced apoptosis. Inhibition of the ID1 bioactivity may become a new strategy in cancer treatment.</p>

Characterization of sphere-forming HCT116 clones by whole RNA sequencing

PURPOSE: To determine CD133+ cells defined as cancer stem cells (CSCs) in colon cancer, we examined whether CD133+ clones in HCT116 demonstrate known features of CSCs like sphere-forming ability, chemodrug-resistance, and metastatic potential. METHODS: Magnetic cell isolation and cell separation demonstrated that <1% of HCT116 cells expressed CD133, with the remaining cells being CD133- clones. In colon cancer cells, radioresistance is also considered a CSC characteristic. We performed clonogenic assay using 0.4 Gy γ-irradiation. RESULTS: Interestingly, there were no differences between HCT116 parental and HCT116 CD133+ clones when the cells comprised 0.5% of the total cells, and CD133- clone demonstrated radiosensitive changes compared with parental and CD133+ clones. Comparing gene expression profiles between sphere-forming and nonforming culture conditions of HCT116 subclones by whole RNA sequencing failed to obtain specific genes expressed in CD133+ clones. CONCLUSION: Despite no differences of gene expression profiles in monolayer attached culture conditions of each clone, sphere-forming conditions of whole HCT116 subclones, parental, CD133+, and CD133- increased 1,761 coding genes and downregulated 1,384 genes related to CSCs self-renewal and survival. Thus, spheroid cultures of HCT116 cells could be useful to expand colorectal CSCs rather than clonal expansion depending on CD133 expressions.

Silencing the livin gene enhances the cytotoxic effects of anticancer drugs on colon cancer cells

PURPOSE: Livin is associated with drug response in several cancers. The aim of this study was to investigate the effect of silencing the livin gene expression on anticancer drug response in colorectal cancer. METHODS: siRNA was transfected at different concentrations (0, 10, and 30nM) into HCT116 cells, then cells were treated with either 5-fluorouracil (FU)/leucovorin (LV) or oxaliplatin (L-OHP)/5-FU/LV. Cellular viability and apoptosis were evaluated following silencing of livin gene expression combined with treatment with anticancer drugs. RESULTS: Livin gene expression was effectively suppressed by 30nM siRNA compared with control and 10nM siRNA. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay showed that proliferation was effectively inhibited in cells treated with a combination of both siRNA and an anticancer drug, compared to cells treated with siRNA-Livin or anticancer drug alone. In particular, the combination of 30nM siRNA and L-OHP/5-FU/LV resulted in a 93.8% and 91.4% decrease, compared to untreated control or L-OHP/5-FU/LV alone, respectively. Cellular proliferation was most effectively suppressed by a combination of 30nM of siRNA and L-OHP/5-FU/LV compared to other combinations. CONCLUSION: siRNA-mediated down-regulation of livin gene expression could significantly suppress colon cancer growth and enhance the cytotoxic effects of anticancer drugs such as 5-FU and L-OHP. The results of this study suggest that silencing livin gene expression in combination with treatment with anticancer drugs might be a novel cancer therapy for colorectal cancer.