OBJECTIVE: To explore the role of the natural compound hesperidin in glycolysis, the key ratelimiting enzyme, in colorectal cancer (CRC) cell lines. METHODS: In vitro, HCT116 and SW620 were treated with different doses of hesperidin (0-500 µmol/L), cell counting kit-8 and colone formation assays were utilized to detected inhibition effect of hesperidin on CRC cell lines. Transwell and wound healing assays were performed to detect the ability of hesperidin (0, 25, 50 and 75 µmol/L) to migrate CRC cells. To confirm the apoptotic-inducing effect of hesperidin, apoptosis and cycle assays were employed. Western blot, glucose uptake, and lactate production determination measurements were applied to determine inhibitory effects of hesperidin (0, 25 and 50 µmol/L) on glycolysis. In vivo, according to the random number table method, nude mice with successful tumor loading were randomly divided into vehicle, low-dose hesperidin (20 mg/kg) and high-dose hesperidin (60 mg/kg) groups, with 6 mice in each group. The body weights and tumor volumes of mice were recorded during 4-week treatment. The expression of key glycolysis rate-limiting enzymes was determined using Western blot, and glucose uptake and lactate production were assessed. Finally, protein interactions were probed with DirectDIA Quantitative Proteomics, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. RESULTS: Hesperidin could inhibit CRC cell line growth (P<0.05 or P<0.01). Moreover, hesperidin presented an inhibitory effect on the migrating abilities of CRC cells. Hesperidin also promoted apoptosis and cell cycle alterations (P<0.05). The immunoblotting results manifested that hesperidin decreased the levels of hexokinase 2, glucose transporter protein 1 (GLUT1), GLUT3, L-lactate dehydrogenase A, 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 2 (PFKFB2), PFKFB3, and pyruvate kinase isozymes M2 (P<0.01). It remarkably suppressed tumor xenograft growth in nude mice. GO and KEGG analyses showed that hesperidin treatment altered metabolic function. CONCLUSION Hesperidin inhibits glycolysis and is a potential therapeutic choice for CRC treatment.
Hesperidin/therapeutic use* ; Colorectal Neoplasms/metabolism* ; Glycolysis/drug effects* ; Animals ; Humans ; Apoptosis/drug effects* ; Mice, Nude ; Cell Movement/drug effects* ; Cell Line, Tumor ; Cell Proliferation/drug effects* ; Glucose/metabolism* ; Cell Cycle/drug effects* ; Mice, Inbred BALB C ; Mice ; HCT116 Cells ; Lactic Acid

This study aims to delve into the influences and underlying mechanisms of Banxia Xiexin Decoction(BXD) on the proliferation, apoptosis, invasion, and migration of colon cancer cells. Firstly, the components of BXD in blood were identified by UPLC-MS/MS, and subsequently the content of these components were determined by HPLC. Then, different concentrations of BXD were used to treat both the normal intestinal epithelial cells(NCM460) and the colon cancer cells(HT29 and HCT116). The cell viability and apoptosis were examined by the cell counting kit-8(CCK-8) and flow cytometry, respectively. Western blot was employed to determine the expression of the apoptosis regulators B-cell lymphoma-2(Bcl-2) and Bcl-2-associated X(Bax). The cell wound healing assay and Transwell assay were employed to measure the cell migration and invasion, respectively. Additionally, Western blot was employed to determine the expression levels of epithelial-mesenchymal transition(EMT)-associated proteins, including epithelial cadherin(E-cadherin), neural cadherin(N-cadherin), and vimentin. The protein and mRNA levels of the factors in the poly(ADP-ribose) glycohydrolase(PARG)/poly(ADP-ribose) polymerase 1(PARP1)/nuclear factor kappa-B p65(NF-κB p65) signaling pathway were determined by Western blot and RT-qPCR, respectively. The results demonstrated that following BXD intervention, the proliferation of HT29 and HCT116 cells was significantly reduced. Furthermore, BXD promoted the apoptosis, enhanced the expression of Bcl-2, and suppressed the expression of Bax in colon cancer cells. At the same time, BXD suppressed the cell migration and invasion and augmented the expression of E-cadherin while diminishing the expression of N-cadherin and vimentin. In addition, BXD down-regulated the protein and mRNA levels of PARG, PARP1, and NF-κB p65. In conclusion, BXD may inhibit the malignant phenotypes of colon cancer cells by mediating the PARG/PARP1/NF-κB signaling pathway.
Colonic Neoplasms/pathology* ; Drugs, Chinese Herbal/pharmacology* ; Phenotype ; Signal Transduction/drug effects* ; Cell Proliferation/drug effects* ; Apoptosis ; Cell Movement/drug effects* ; Neoplasm Invasiveness ; HCT116 Cells ; Proto-Oncogene Proteins c-bcl-2/biosynthesis* ; Humans ; Poly (ADP-Ribose) Polymerase-1 ; Glycoside Hydrolases ; bcl-2-Associated X Protein ; NF-kappa B p50 Subunit

OBJECTIVES: To explore the expression of hexokinase 2 (HK2) in colorectal cancer (CRC) and its possible mechanisms for regulating tumor cell behaviors and tumor immune microenvironment. METHODS: We analyzed HK2 expression in CRC and its impact on patient prognosis and tumor immune microenvironment using public databases. HK2 expression was also examined in 8 CRC and paired adjacent tissues using immunohistochemistry, Western blotting and RT-qPCR. In cultured CRC cell lines CT26 and HCT116 with low HK2 expression, the effects of lentivirus-mediated HK2 overexpression and JAK/STAT3 inhibitors on cell proliferation, migration, and invasion were assessed using CCK-8 assay, colony formation assay and Transwell assay and in a subcutaneous tumor-bearing mouse model; the changes were also observed in MC38 and CACO2 cells with high HK2 expressions following treatment with HK2 inhibitor 3-BP. Western blotting was performed to verify the relationship between HK2 and JAK/STAT signaling pathway protein expressions. RESULTS: Informatics analyses suggested that HK2 expression was significantly higher in CRC tissues than in adjacent tissues (P<0.001), and patients with high HK2 expressions had worse prognosis (P=0.09). In the 8 clinical CRC tissues, HK2 expressions were significantly higher in the tumor tissues than in the adjacent tissues (P<0.01). In CT26 and HCT116 cells, HK2 overexpression significantly enhanced cell proliferation, migration and invasion, while in HK2-overexpressing MC38 and CACO2 cells, inhibiting HK2 with 3-BP strongly suppressed these changes. HK2 overexpression promoted STAT3 phosphorylation, and JAK/STAT3 inhibitors effectively suppressed tumor cell proliferation, migration and invasion. TIMER and MCPcounter analyses indicated correlations between HK2 and immune cells, and TCGA and GEO analyses suggested significant positive correlations between HK2 and the immune checkpoints including PDCD1. CONCLUSIONS HK2 is upregulated in CRC to promote tumor cell proliferation, migration and invasion possibly by activating the JAK-STAT signaling pathway and modulating tumor immune microenvironment.
Humans ; Colorectal Neoplasms/metabolism* ; Cell Proliferation ; Hexokinase/genetics* ; Tumor Microenvironment ; Cell Movement ; Signal Transduction ; Animals ; STAT3 Transcription Factor/metabolism* ; Mice ; Neoplasm Invasiveness ; Cell Line, Tumor ; Janus Kinases/metabolism* ; HCT116 Cells ; Caco-2 Cells

OBJECTIVES: To investigate the regulatory role of Ral guanine nucleotide dissociation stimulator-like 1 (RGL1) in metastasis of colorectal cancer (CRC). METHODS: We analyzed the differential expression of RGL1 between metastatic and non-metastatic CRC in GEO database, and examined its expression in 25 patients with metastatic CRC and 25 patients with non-metastatic CRC treated in Zhujiang Hospital between January, 2020 and December, 2022 using quantitative PCR (qPCR) and immunohistochemistry. HCT116 cell lines with stable RGL1 overexpression and SW480 cells with RGL1 knockdown were established using lentiviral vecors, and the changes in invasion and migration abilities of the cells were assessed using Transwell invasion and migration assays. The transduced cells were injected into the serosa of the cecum of nude mice, and tumor growth and liver metastasis were observed 8 weeks later. Fibronectin adhesion assays and immunofluorescence experiments were employed to assess the relationship between RGL1 and focal adhesion formation, and co-immuno-precipitation assays were performed to explore the interaction between RGL1 and GTPase activation. RESULTS: Compared with non-metastatic CRC, metastatic CRC showed significantly upregulated expression of RGL1. HCT116 cells overexpressing RGL1 exhibited obviously enhanced migration and invasion in vitro with increased capacity for liver metastasis in nude mice. RGL1 overexpression strongly accelerated focal adhesion assembly, facilitated the formation of motile focal adhesions, and enhanced the binding of activated CDC42/RAC1 complex to RGL1. CONCLUSIONS RGL1 is highly expressed in metastatic CRC and promotes distant metastasis of CRC by activating the CDC42/RAC1 complex to facilitate the formation of motile focal adhesions. These findings suggest that RGL1 can potentially serve as a therapeutic target for CRC metastasis.
Humans ; Colorectal Neoplasms/metabolism* ; cdc42 GTP-Binding Protein/metabolism* ; Animals ; Mice, Nude ; rac1 GTP-Binding Protein/metabolism* ; Cell Movement ; Mice ; Focal Adhesions/metabolism* ; Neoplasm Metastasis ; Cell Line, Tumor ; HCT116 Cells ; Up-Regulation ; Neoplasm Invasiveness ; Adaptor Proteins, Signal Transducing ; Female ; Rho Guanine Nucleotide Exchange Factors

This study investigated the effects of Agrimoniae Herba-Coptidis Rhizoma(XHC-HL)-medicated serum on the proliferation, migration, invasion, and apoptosis of human colorectal cancer HT29 and HCT116 cells via the autophagy mediated by lysosome-associated membrane protein type 2A(LAMP2A). Bioinformatics analysis was conducted to explore the role of LAMP2A in the development and progression of colorectal cancer. Western blot(WB) was used to detect the expression of LAMP2A protein in colorectal cancer cell lines. Lentiviral transfection was utilized to construct LAMP2A knockdown in HT29 and overexpression in HCT116 colorectal cancer cell models. Real-time fluorescence quantitative polymerase chain reaction(real-time qPCR) was performed to assess transfection efficiency. HT29 and HCT116 cells were treated with different concentrations of XHC-HL-medicated serum. The cell counting kit-8(CCK-8) assay was used to detect cell proliferation and determine the optimal concentration and duration of medicated serum intervention. HT29 cells were divided into a normal control(NC) group, an XHC-HL(medicated serum treatment) group, and an XHC-HL+shLAMP2A(medicated serum treatment+LAMP2A knockdown) group. HCT116 cells were divided into a NC group, an XHC-HL group, and an XHC-HL+LAMP2A(medicated serum treatment+LAMP2A overexpression) group. CCK-8 was used to measure cell viability. Colony formation assay was employed to assess cell proliferation ability. Scratch and Transwell migration assays were conducted to evaluate cell migration ability, and Transwell invasion assay was used to detect cell invasion ability. Flow cytometry was adopted to determine apoptosis rates. WB and real-time qPCR were employed to detect the effect of XHC-HL on the protein and mRNA expression of LAMP2A, heat shock cognate protein 70(HSC70), heat shock protein 90(HSP90), and glyceraldehyde-3-phosphate dehydrogenase(GAPDH) in colorectal cancer cells. Differential expression analysis revealed that LAMP2A expression was significantly higher in colorectal cancer patients compared to that in normal controls. Survival analysis indicated that the key molecule of chaperone-mediated autophagy(CMA), LAMP2A, was closely associated with colorectal cancer progression. Gene set enrichment analysis showed that patients with high LAMP2A expression significantly upregulated tumor progression-related signaling pathways such as angiogenesis and immune suppression. Immune infiltration analysis found that patients with high LAMP2A expression had fewer CD8 T cell infiltrations in their tumor microenvironment. XHC-HL-medicated serum inhibited the viability of HT29 and HCT116 cells, with the optimal intervention concentration and duration being 20% and 48 hours, respectively. Compared to the NC group, XHC-HL inhibited the proliferation, migration, and invasion of HT29 and HCT116 cells, and induced apoptosis. The medicated serum treatment with LAMP2A knockdown further inhibited colorectal cancer cell proliferation, invasion, and migration, and promoted apoptosis, whereas overexpression of LAMP2A reversed the inhibitory effects of the medicated serum on proliferation, migration, and invasion, and reduced apoptosis rates. XHC-HL-medicated serum inhibited CMA by upregulating the protein and mRNA expression of LAMP2A, HSC70, and HSP90 and downregulating substrate protein GAPDH expression via the autophagy mediated by LAMP2A. In conclusion, XHC-HL-medicated serum inhibits the proliferation, migration, and invasion of colorectal cancer cells and induces apoptosis by downregulating the expression of the key CMA molecule LAMP2A and inhibiting CMA activity.
Humans ; Colorectal Neoplasms/pathology* ; Drugs, Chinese Herbal/pharmacology* ; Lysosomal-Associated Membrane Protein 2/metabolism* ; Cell Proliferation/drug effects* ; Autophagy/drug effects* ; HCT116 Cells ; Cell Movement/drug effects* ; Apoptosis/drug effects* ; HT29 Cells ; Serum/chemistry* ; Coptis chinensis

Through in vitro and in vivo experiments, combined with network pharmacology and molecular docking techniques, this study investigated the mechanism of action of osthole in the treatment of colorectal cancer(CRC). The relevant targets of osthole and CRC were retrieved from the SwissTargetPrediction and SuperPred in drug databases, as well as GeneCards and OMIM in disease databases. Protein-protein interaction(PPI) networks were constructed using the STRING database and Cytoscape 3.8.0 software, and core targets were screened. Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analyses were performed on common targets. Molecular docking validation of core targets with osthole was conducted using AutoDock Vina software. HCT116 cells were treated with different concentrations of osthole, and cell proliferation was detected using the CCK-8 assay and the clonogenic assay. Cell migration ability was assessed using Transwell assay. Western blot and RT-qPCR were performed to detect the expression of caspase-3(CASP3), hypoxia-inducible factor 1 alpha(HIF1A), nuclear factor kappa B subunit 1(NFKB1), glycogen synthase kinase-3 beta(GSK3B), phosphorylated-GSK3B(p-GSK3B), protein kinase B(Akt), phosphorylated-Akt(p-Akt), mammalian target of rapamycin(mTOR), and phosphorylated-mTOR(p-mTOR). A subcutaneous tumor model of HCT116 cells in nude mice was established, and the mice were randomly divided into the model group, low-dose osthole group(20 mg·kg~(-1)), medium-dose osthole group(40 mg·kg~(-1)), and high-dose osthole group(60 mg·kg~(-1)). After 18 days of administration, the growth of tumor xenografts was observed, and the size and weight of tumors were measured after excision. Hematoxylin-eosin(HE) staining was performed to observe the histological changes in tumors in each group. Network pharmacology analysis revealed that osthole treatment of CRC mainly involved 106 treatment targets and 113 treatment pathways, with key pathways including the PI3K/Akt signaling pathway and MAPK signaling pathway. Molecular docking results showed a strong correlation between osthole and core targets. In vitro studies demonstrated that osthole significantly inhibited the proliferation and migration ability of HCT116 cells. Western blot and RT-qPCR experiments showed that compared to those in the model group, the expression of NFKB1, HIF1A, p-Akt, p-mTOR, and GSK3B in the osthole-treated group was significantly decreased, while the expression of CASP3 and p-GSK3B(Ser9) was significantly increased. In vivo studies showed that compared to the model group, osthole-fed animals significantly reduced tumor weight and volume, inhibited tumor growth, and promoted tumor apoptosis, and the results showed a dose-dependent trend. The study suggested that osthole could inhibit the proliferation and migration of HCT116 cells in CRC, and its mechanism may be related to the regulation of the PI3K/Akt signaling pathway and the expression of core targets.
Coumarins/chemistry* ; Humans ; Molecular Docking Simulation ; Colorectal Neoplasms/pathology* ; Animals ; Network Pharmacology ; Mice ; Cell Proliferation/drug effects* ; HCT116 Cells ; Mice, Nude ; Mice, Inbred BALB C ; Proto-Oncogene Proteins c-akt/genetics* ; TOR Serine-Threonine Kinases/genetics* ; Cell Movement/drug effects* ; Apoptosis/drug effects* ; Signal Transduction/drug effects* ; Protein Interaction Maps/drug effects*

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.
Humans ; Colonic Neoplasms ; HCT116 Cells ; Cell Line, Tumor ; Cell Proliferation ; Gene Expression Regulation, Neoplastic ; RNA, Messenger ; Glucose ; Calcium-Binding Proteins/metabolism* ; Adaptor Proteins, Signal Transducing/metabolism* ; 14-3-3 Proteins/metabolism*

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.
CRISPR-Cas Systems/genetics* ; Gene Editing ; Gene Knockout Techniques ; HCT116 Cells ; Humans ; RNA, Guide/metabolism*

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.
Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Colonic Neoplasms/drug therapy* ; HCT116 Cells ; Humans ; Phosphatidylinositol 3-Kinases/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Signal Transduction ; Syzygium ; TOR Serine-Threonine Kinases/metabolism*

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.
Blotting, Western ; Colon ; Colonic Neoplasms ; Cyclooxygenase 2 ; DNA ; Down-Regulation ; Electrophoretic Mobility Shift Assay ; HCT116 Cells ; Heme Oxygenase-1 ; Heme ; Humans ; Oligonucleotide Array Sequence Analysis ; Oxidoreductases ; Peroxisomes ; Phosphorylation ; Phosphotransferases ; RNA, Messenger ; RNA, Small Interfering ; Transcription Factor AP-1 ; Transfection ; Up-Regulation ; Zinc