Activating transcription factor 3 is an antitumor gene synergizing with growth differentiation factor 15 to modulate cell growth in human bladder cancer.

BACKGROUND: The functions of activating transcription factor 3 (ATF3) within the human bladder remain unexplored. This study delves into the expressions, functions, and regulatory mechanisms of ATF3 in human bladder cancer. MATERIAL AND METHODS: Gene expressions were determined by immunoblot, RT-qPCR, and reporter assays. Assays of Ki67, colony formation, Matrigel invasion, and the xenograft animal study were used to assess the cell proliferation, invasion, and tumorigenesis in vitro and in vivo. Silico analysis from TCGA database examined the correlations between GDF15 and ATF3 expressions, clinicopathologic features, and progression-free survival rates. RESULTS: Silico analysis confirmed that ATF3 is an antitumor gene, and the expression positively correlates with GDF15 in bladder cancer tissues. Multivariate analysis revealed that low ATF3/GDF15 but not a single low expression of ATF3 is an independent prognostic factor for progression-free survival of bladder cancer patients. Ectopic overexpression of ATF3 downregulated cell proliferation and invasion in bladder cancer cells in vitro, while ATF3-knockdown reversed these results. Knockdown of ATF3 upregulated EMT markers to enhance cell invasion in vitro and downregulated GDF15, NDRG1, and KAI-1 to elevate tumor growth in vivo. The activation of metformin on ATF3 and GDF15 in bladder cancer cells was blocked by SB431542, a TGFß receptor inhibitor. ATF3 positively regulated GDF15 expression in bladder cancer cells through a feedback loop. CONCLUSIONS: Our results identify that ATF3 is a metformin-upregulated antitumor gene. Results of Silico analysis align with cell-based studies suggesting that low ATF3/GDF15 could be a negative prognostic marker for bladder cancer.

Investigating the Genetic Diversity of Hepatitis Delta Virus in Hepatocellular Carcinoma (HCC): Impact on Viral Evolution and Oncogenesis in HCC.

Hepatitis delta virus (HDV), an RNA virus with two forms of the delta antigen (HDAg), relies on hepatitis B virus (HBV) for envelope proteins essential for hepatocyte entry. Hepatocellular carcinoma (HCC) ranks third in global cancer deaths, yet HDV's involvement remains uncertain. Among 300 HBV-associated HCC serum samples from Taiwan's National Health Research Institutes, 2.7% (8/300) tested anti-HDV positive, with 62.7% (5/8) of these also HDV RNA positive. Genotyping revealed HDV-2 in one sample, HDV-4 in two, and two samples showed mixed HDV-2/HDV-4 infection with RNA recombination. A mixed-genotype infection revealed novel mutations at the polyadenylation signal, coinciding with the ochre termination codon for the L-HDAg. To delve deeper into the possible oncogenic properties of HDV-2, the predominant genotype in Taiwan, which was previously thought to be less associated with severe disease outcomes, an HDV-2 cDNA clone was isolated from HCC for study. It demonstrated a replication level reaching up to 74% of that observed for a widely used HDV-1 strain in transfected cultured cells. Surprisingly, both forms of HDV-2 HDAg promoted cell migration and invasion, affecting the rearrangement of actin cytoskeleton and the expression of epithelial-mesenchymal transition markers. In summary, this study underscores the prevalence of HDV-2, HDV-4, and their mixed infections in HCC, highlighting the genetic diversity in HCC as well as the potential role of both forms of the HDAg in HCC oncogenesis.

Androgen Receptor Upregulates Mucosa-Associated Lymphoid Tissue 1 to Induce NF-κB Activity via Androgen-Dependent and -Independent Pathways in Prostate Carcinoma Cells.

The androgen-dependent or -independent pathways are regarded as primary therapeutic targets for the neoplasm of the prostate. Mucosa-associated lymphoid tissue 1 (MALT1) acting as a paracaspase in the regulation of nuclear factor κB (NF-κB) signal transduction plays a central role in inflammation and oncogenesis in cancers. This study confirmed the potential linkages between androgen and NF-κB activation by inducing MALT1 in the androgen receptor-full length (ARFL)-positive LNCaP and 22Rv1 prostate cancer cells. Although androgen did not stimulate MALT1 expression in AR-null or ectopic ARFL-overexpressed PC-3 cells, the ectopic overexpression of the AR splicing variant 7 (ARv7) upregulated MALT1 to activate NF-κB activities in 22Rv1 and PC-3 cells. Since the nuclear translocation of p50 and p65 was facilitated by ARv7 to motivate NF-κB activity, the expressions of MALT1, prostate-specific antigen (PSA), and N-myc downstream regulated 1 (NDRG1) were therefore induced in ectopic ARv7-overexpressed prostate cancer cells. Ectopic ARv7 overexpression not only enhanced 22Rv1 or PC-3 cell growth and invasion in vitro but also the tumor growth of PC-3 cells in vivo. These results indicate that an androgen receptor induces MALT1 expression androgen-dependently and -independently in ARFL- or ARv7-overexpressed prostate cancer cells, suggesting a novel ARv7/MALT1/NF-κB-signaling pathway may exist in the cells of prostate cancer.

WNT1 Inducible Signaling Pathway Protein 1 Is a Stroma-Specific Secreting Protein Inducing a Fibroblast Contraction and Carcinoma Cell Growth in the Human Prostate.

The WNT1 inducible signaling pathway protein 1 (WISP1), a member of the connective tissue growth factor family, plays a crucial role in several important cellular functions in a highly tissue-specific manner. Results of a RT-qPCR indicated that WISP1 expressed only in cells of the human prostate fibroblasts, HPrF and WPMY-1, but not the prostate carcinoma cells in vitro. Two major isoforms (WISP1v1 and WISP1v2) were identified in the HPrF cells determined by RT-PCR and immunoblot assays. The knock-down of a WISP1 blocked cell proliferation and contraction, while treating respectively with the conditioned medium from the ectopic WISP1v1- and WISPv2-overexpressed 293T cells enhanced the migration of HPrF cells. The TNFα induced WISP1 secretion and cell contraction while the knock-down of WISP1 attenuated these effects, although TNFα did not affect the proliferation of the HPrF cells. The ectopic overexpression of WISP1v1 but not WISP1v2 downregulated the N-myc downstream regulated 1 (NDRG1) while upregulating N-cadherin, slug, snail, and vimentin gene expressions which induced not only the cell proliferation and invasion in vitro but also tumor growth of prostate carcinoma cells in vivo. The results confirmed that WISP1 is a stroma-specific secreting protein, enhancing the cell migration and contraction of prostate fibroblasts, as well as the proliferation, invasion, and tumor growth of prostate carcinoma cells.

Metallothionein 2A with Antioxidant and Antitumor Activity Is Upregulated by Caffeic Acid Phenethyl Ester in Human Bladder Carcinoma Cells.

Functions of metallothionein 2A (MT2A) in bladder cancer have not been extensively explored even though metallothioneins are regarded as modulators in several biological regulations including oxidation and cancerous development. We evaluated MT2A in bladder carcinoma cells in terms of the mechanisms of regulation and the underlying functions. MT2A overexpression not only downregulated endogenous ROS but also blocked ROS induced by H2O2. We used the annexin V-FITC apoptosis assay to determine the modulation of H2O2-induced cell apoptosis by MT2A expression. Results of immunoblot and reporter assays indicated that caffeic acid phenethyl ester (CAPE) treatment induced MT2A and heme oxygenase-1 (HO-1) expressions; moreover, the involvement of CAPE in either upregulation of the HO-1 expression or downregulation of endogenous ROS is MT2A dependent in bladder carcinoma cells. Knockdown of MT2A increased invasion and cell growth in vitro and in vivo, whereas ectopic overexpression of MT2A had the reverse effect in bladder carcinoma cells. Unlike bladder cancer tissues, the real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) analysis showed a significant level of MT2A mRNA in the normal bladder tissues. Collectively, our results indicated that MT2A is acting as an antioxidant and also a tumor suppressor in human bladder carcinoma cells.

The Upregulation of Caffeic Acid Phenethyl Ester on Growth Differentiation Factor 15 Inhibits Transforming Growth Factor ß/Smad Signaling in Bladder Carcinoma Cells.

Growth differentiation factor 15 (GDF15) is known as a TGFß-like cytokine acting on the TGFß receptor to modulate target genes. GDF15 is regarded as a tumor suppressor gene in the human bladder and the caffeic acid phenethyl ester (CAPE) induces GDF15 expression to inhibit the tumor growth in vitro and in vivo. However, the interactions among GDF15, CAPE, and TGFß/Smads signaling in the human bladder carcinoma cells remain unexplored. Results revealed that TGFß downregulated the expression of GDF15 via the activation of Smad 2/3 and Smad 1/5. Induction of GDF15 on its downstream genes, NDRG1 and maspin, is dependent on the TGFß/Smad pathways. Moreover, TGFß blocked the CAPE-inducing expressions of GDF15, maspin, and NDRG1. Pretreatment of TGF receptor kinase inhibitor not only blocked the activation of TGFß but also attenuated the activation of GDF15 on the expressions of maspin and NDRG1. The CAPE treatment attenuated the activation of TGFß on cell proliferation and invasion. Our findings indicate that TGFß downregulated the expressions of GDF15, maspin, and NDRG1 via TGFß/Smad signaling. Whereas, CAPE acts as an antagonist on TGFß/Smad signaling to block the effect of TGFß on the GDF15 expression and cell proliferation and invasion in bladder carcinoma cells.

The Antitumor Effect of Caffeic Acid Phenethyl Ester by Downregulating Mucosa-Associated Lymphoid Tissue 1 via AR/p53/NF-κB Signaling in Prostate Carcinoma Cells.

Caffeic acid phenethyl ester (CAPE), a honeybee propolis-derived bioactive ingredient, has not been extensively elucidated regarding its effect on prostate cancer and associated mechanisms. The mucosa-associated lymphoid tissue 1 gene (MALT1) modulates NF-κB signal transduction in lymphoma and non-lymphoma cells. We investigated the functions and regulatory mechanisms of CAPE in relation to MALT1 in prostate carcinoma cells. In p53- and androgen receptor (AR)-positive prostate carcinoma cells, CAPE downregulated AR and MALT1 expression but enhanced that of p53, thus decreasing androgen-induced activation of MALT1 and prostate-specific antigen expressions. p53 downregulated the expression of MALT in prostate carcinoma cells through the putative consensus and nonconsensus p53 response elements. CAPE downregulated MALT1 expression and thus inhibited NF-κB activity in p53- and AR-negative prostate carcinoma PC-3 cells, eventually reducing cell proliferation, invasion, and tumor growth in vitro and in vivo. CAPE induced the ERK/JNK/p38/AMPKα1/2 signaling pathways; however, pretreatment with the corresponding inhibitors of MAPK or AMPK1/2 did not inhibit the CAPE effect on MALT1 blocking in PC-3 cells. Our findings verify that CAPE is an effective antitumor agent for human androgen-dependent and -independent prostate carcinoma cells in vitro and in vivo through the inhibition of MALT1 expression via the AR/p53/NF-κB signaling pathways.

Caffeic acid phenethyl ester inhibits the growth of bladder carcinoma cells by upregulating growth differentiation factor 15.

BACKGROUND: Caffeic acid phenethyl ester (CAPE), a bioactive component of propolis, has beneficial effects on cancer prevention. Growth differentiation factor 15 (GDF15) is an antitumor gene of bladder cancer. Therefore, this study investigated the anti-cancer effect of CAPE on bladder carcinoma cells and related mechanisms. METHODS: The expressions of GDF15, N-myc downstream-regulated gene 1 (NDRG1), and maspin, and the activations of extracellular signal regulated kinase (ERK), c-jun Nterminal kinase (JNK), p38, and 50 adenosine monophosphate-activated protein kinase (AMPK) α1/2 in human bladder cells after gene transfection or knockdown were determined by immunoblot, real-time reverse transcriptase-polymerase chain reaction (RT-qPCR), and reporter assays. The assays of 5-ethynyl-2'-deoxyuridine (EdU), CyQUANT cell proliferation, and Matrigel invasion, and the xenograft animal study were used to assess the cell proliferation, invasion, and tumorigenesis. RESULTS: GDF15 expression in epithelial cells was negatively correlated with neoplasia in vitro. Also, GDF15 exhibits in bladder fibroblasts and smooth muscle cells. CAPE-induced expressions of NDRG1 and maspin decreased cell proliferation and invasion of bladder carcinoma cells in a GDF15-dependent manner in vitro. The xenograft animal study suggesting CAPE attenuated tumor growth in vivo. CAPE increased phosphorylation of ERK, JNK, p38, and AMPKα1/2 to modulate the GDF15 expressions. Pretreatments with ERK, JNK, or p38 inhibitors partially inhibited the CAPE effects on the inductions of GDF15, NDRG1, or maspin. Knockdown of AMPKα1/2 attenuated the CAPE-induced GDF15 expression and cell proliferation in bladder carcinoma cells. CONCLUSIONS: Our findings indicate that CAPE is a promising agent for anti-tumor growth in human bladder carcinoma cells via the upregulation of GDF15.

Mucosa-Associated Lymphoid Tissue 1 Is an Oncogene Inducing Cell Proliferation, Invasion, and Tumor Growth via the Upregulation of NF-κB Activity in Human Prostate Carcinoma Cells.

Prostate cancer is one of the most common seen malignancies and the leading cause of cancer-related death among men. Given the importance of early diagnosis and treatment, it is worth to identify a potential novel therapeutic target for prostate cancer. Mucosa-associated lymphoid tissue 1 (MALT1) is a novel gene involved in nuclear factor κB (NF-κB) signal transduction by acting as an adaptor protein and paracaspase, with an essential role in inflammation and tumorigenesis in many cancers. This study investigated the functions and the potential regulatory mechanisms of MALT1 in the human prostate cancer cells. We found that MALT1 is abundant in prostate cancer tissues. MALT1 facilitated NF-κB subunits (p50 and p65) nuclear translocation to induce gene expression of interleukin 6 (IL-6) and C-X-C motif chemokine 5 (CXCL5) in prostate carcinoma cells. MALT1 promoted cell proliferation, invasion, and tumor growth in vitro and in vivo. MALT1 enhanced NF-κB activity in prostate carcinoma cells; moreover, NF-κB induced MALT1 expression determined by reporter and immunoblot assays, implying there is a positive feedback loop between MALT1 and NF-κB. In conclusion, MALT1 is a NF-κB-induced oncogene in the human prostate carcinoma cells.

Human Heme Oxygenase-1 Induced by Interleukin-6 via JAK/STAT3 Pathways Is a Tumor Suppressor Gene in Hepatoma Cells.

Heme oxygenase-1 (HO-1) has several important roles in hepatocytes in terms of anti-inflammation, anti-apoptosis, and antioxidant properties. Interleukin-6 (IL-6) is a pleiotropic cytokine associated with liver regeneration and protection against injury. The aim of this study was to determine the potential crosstalk between HO-1 and IL-6, and to elucidate the signaling pathways involved in the induction of HO-1 by IL-6 in human hepatoma cells. Ectopic overexpression of HO-1 not only attenuated cell proliferation in vitro and in vivo, but also blocked the reactive oxygen species (ROS) induced by H2O2 and the pyocyanin in HepG2 or Hep3B cells. IL-6 expression was negatively regulated by HO-1, while IL-6 induced signal transducer and activator of transcription 3 (STAT3) phosphorylation and HO-1 gene expression in HepG2 cells. The co-transfected HO-1 reporter vector and a protein inhibitor of the activated STAT3 (PIAS3) expression vector blocked the IL-6-induced HO-1 reporter activity. Both interferon γ and interleukin-1ß treatments induced STAT1 but not STAT3 phosphorylation, which had no effects on the HO-1 expression. Treatments of AG490 and luteolin blocked the JAK/STAT3 signaling pathways which attenuated IL-6 activation on the HO-1 expression. Our results indicated that HO-1 is the antitumor gene induced by IL-6 through the IL-6/JAK/STAT3 pathways; moreover, a feedback circuit may exist between IL-6 and HO-1 in hepatoma cells.

Antioxidation and Antiapoptosis Characteristics of Heme Oxygenase-1 Enhance Tumorigenesis of Human Prostate Carcinoma Cells.

Heme oxygenase-1 (HO-1) has antiinflammatory and antioxidant properties and is deemed as a tissue protector. However, effects of HO-1 in prostate cancer remain in controversy. We evaluated the role of HO-1 in prostate carcinoma in vitro and in vivo. Overexpression of HO-1 did not affect prostate cell proliferation in the normal condition but enhanced cell proliferation under serum starvation. HO-1 overexpression enhanced cell invasion of PC-3 cells through epithelial-mesenchymal transition (EMT) induction, which was supported by increased Slug, N-cadherin, and vimentin expressions. In the xenograft animal study, HO-1 overexpression enhanced PC-3 cell tumor growth in vivo. HO-1 attenuated reactive oxygen species induced by H2O2 or pyocyanin treatment in PC-3 and DU145 cells. HO-1 further reduced PC-3 and DU145 cell apoptosis induced by H2O2 or serum starvation. Our results suggested that HO-1 was able to increase prostate carcinoma cell invasion in vitro and tumor growth in vivo. The EMT induction and antioxidant and antiapoptotic effects of HO-1 in the prostate carcinoma cells may be responsible for these findings.

Maspin is a PTEN-Upregulated and p53-Upregulated Tumor Suppressor Gene and Acts as an HDAC1 Inhibitor in Human Bladder Cancer.

Maspin is a member of the clade B serine protease inhibitor superfamily and exhibits diverse regulatory effects in various types of solid tumors. We compared the expressions of maspin and determined its potential biological functions and regulatory mechanisms in bladder carcinoma cells in vitro and in vivo. The results of RT-qPCR indicated that maspin expressed significantly lower levels in the bladder cancer tissues than in the paired normal tissues. The immunohistochemical assays of human bladder tissue arrays revealed similar results. Maspin-knockdown enhanced cell invasion whereas the overexpression of maspin resulted in the opposite process taking place. Knockdown of maspin also enhanced tumorigenesis in vivo and downregulated protein levels of acetyl-histone H3. Moreover, in bladder carcinoma cells, maspin modulated HDAC1 target genes, including cyclin D1, p21, MMP9, and vimentin. Treatment with MK2206, which is an Akt inhibitor, upregulated maspin expression, whereas PTEN-knockdown or PTEN activity inhibitor (VO-OHpic) treatments demonstrated reverse results. The ectopic overexpression of p53 or camptothecin treatment induced maspin expression. Our study indicated that maspin is a PTEN-upregulated and p53-upregulated gene that blocks cell growth in vitro and in vivo, and may act as an HDAC1 inhibitor in bladder carcinoma cells. We consider that maspin is a potential tumor suppressor gene in bladder cancer.

Transgelin, a p53 and PTEN-Upregulated Gene, Inhibits the Cell Proliferation and Invasion of Human Bladder Carcinoma Cells in Vitro and in Vivo.

Transgelin (TAGLN/SM22-α) is a regulator of the actin cytoskeleton, affecting the survival, migration, and apoptosis of various cancer cells divergently; however, the roles of TAGLN in bladder carcinoma cells remain inconclusive. We compared expressions of TAGLN in human bladder carcinoma cells to the normal human bladder tissues to determine the potential biological functions and regulatory mechanisms of TAGLN in bladder carcinoma cells. Results of RT-qPCR and immunoblot assays indicated that TAGLN expressions were higher in bladder smooth muscle cells, fibroblast cells, and normal epithelial cells than in carcinoma cells (RT-4, HT1376, TSGH-8301, and T24) in vitro. Besides, the results of RT-qPCR revealed that TAGLN expressions were higher in normal tissues than the paired tumor tissues. In vitro, TAGLN knockdown enhanced cell proliferation and invasion, while overexpression of TAGLN had the inverse effects in bladder carcinoma cells. Meanwhile, ectopic overexpression of TAGLN attenuated tumorigenesis in vivo. Immunofluorescence and immunoblot assays showed that TAGLN was predominantly in the cytosol and colocalized with F-actin. Ectopic overexpression of either p53 or PTEN induced TAGLN expression, while p53 knockdown downregulated TAGLN expression in bladder carcinoma cells. Our results indicate that TAGLN is a p53 and PTEN-upregulated gene, expressing higher levels in normal bladder epithelial cells than carcinoma cells. Further, TAGLN inhibited cell proliferation and invasion in vitro and blocked tumorigenesis in vivo. Collectively, it can be concluded that TAGLN is an antitumor gene in the human bladder.

Migration and Invasion Enhancer 1 Is an NF-ĸB-Inducing Gene Enhancing the Cell Proliferation and Invasion Ability of Human Prostate Carcinoma Cells In Vitro and In Vivo.

: Migration and invasion enhancer 1 (MIEN1) is a membrane-anchored protein and exists in various cancerous tissues. However, the roles of MIEN1 in prostate cancer have not yet been clearly addressed. We determined the expression, biological functions, and regulatory mechanisms of MIEN1 in the prostate. The results of immunohistochemical analysis indicated that MIEN1 was expressed specifically in epithelial cells and significantly higher in adenocarcinoma as compared to in normal tissues. MIEN1 enhanced in vitro cell proliferation, invasion, and in vivo tumorigenesis. Meanwhile, MIEN1 attenuated cisplatin-induced apoptosis in PC-3 cells. Overexpression of NF-ĸB-inducing kinase (NIK) enhanced MIEN1 expression, while overexpression of NF-ĸB inhibitor α (IĸBα) blocked MIEN1 expression in PC-3 cells. In prostate carcinoma cells, MIEN1 provoked Akt phosphorylation; moreover, MIEN1 downregulated N-myc downstream regulated 1 (NDRG1) but upregulated interleukin-6 (IL-6) gene expression. MK2206, an Akt inhibitor, impeded the modulation of MIEN1 on NDRG1 and IL-6 expressions. Our studies suggest that MIEN1 is an NF-ĸB downstream oncogene in the human prostate. Accordingly, the modulation of Akt signaling in the gene expressions of NDRG1 and IL-6 may account for the functions of MIEN1 in cell proliferation, invasion, and tumorigenesis in prostate carcinoma cells.

Metallothionein 3 Is a Hypoxia-Upregulated Oncogene Enhancing Cell Invasion and Tumorigenesis in Human Bladder Carcinoma Cells.

Metallothioneins have been viewed as modulators in a number of biological regulations regarding cancerous development; however, the function of metallothionein 3 (MT3) in bladder cancer is unexplored. We determined the regulatory mechanisms and potential function of MT3 in bladder carcinoma cells. Real-Time Reverse Transcriptase-Polymerase Chain Reaction (RT-qPCR) assays revealed that TSGH-8301 cells expressed more MT3 levels than RT-4, HT1376, and T24 cells. Immunoblot and RT-qPCR assays showed that arsenic (AS2O3) treatments enhanced the gene expression of MT3. Hypoxia induced HIF-1α, HIF-2α, and MT3 expression; furthermore, HIF-2α-knockdown attenuated hypoxic activation on MT3 expression. Ectopic overexpression of MT3 increased cell proliferation, invasion, and tumorigenesis significantly in T24 and HT1376 cells in vitro and in vivo; however, MT3-knockdown in TSGH-8301 cells had the reverse effect. Moreover, knockdown of MT3 enhanced arsenic-induced apoptosis determined by the Annexin V-FITC apoptosis assay. MT3-overexpression downregulated the gene expressions of N-myc downstream regulated gene 1 (NDRG1), N-myc downstream regulated gene 2 (NDRG2), and the mammary serine protease inhibitor (MASPIN) in HT1376 and T24 cells, whereas MT3-knockdown in TSGH-8301 cells had the opposite effect. The experiments indicated that MT3 is an arsenic- and hypoxia-upregulated oncogene that promotes cell growth and invasion of bladder carcinoma cells via downregulation of NDRG1, NDRG2, and MASPIN expressions.

Caffeic Acid Phenethyl Ester Induces N-myc Downstream Regulated Gene 1 to Inhibit Cell Proliferation and Invasion of Human Nasopharyngeal Cancer Cells.

Caffeic acid phenethyl ester (CAPE), a bioactive component extracted from propolis, is widely studied due to its anti-cancer effect. Nasopharyngeal carcinoma (NPC) is distinct from other head and neck carcinomas and has a high risk of distant metastases. N-myc downstream regulated gene 1 (NDRG1) is demonstrated as a tumor suppressor gene in several cancers. Our result showed that CAPE treatment could repress NPC cell growth, through induction of S phase cell cycle arrest, and invasion. CAPE treatment stimulated NDRG1 expression in NPC cells. NDRG1 knockdown increased NPC cell proliferation and invasion and rendered NPC cells less responsive to CAPE growth-inhibiting effect, indicating CAPE repressed NPC cell growth partly through NDRG1indcution. CAPE treatment increased phosphorylation of ERK, JNK, and p38 in a dose- and time-dependent manner. Pre-treatments by inhibitors of ERK (PD0325901), JNK (SP600125), or p38 (SB201290), respectively, all could partly inhibit the CAPE effect on NDRG1 induction in NPC cells. Further, STAT3 activity was also repressed by CAPE in NPC cells. In summary, CAPE attenuates NPC cell proliferation and invasion by upregulating NDRG1 expression via MAPK pathway and by inhibiting phosphorylation of STAT3. Considering the poor prognosis of NPC patients with metastasis, CAPE could be a promising agent against NPC.

BTG2 is a tumor suppressor gene upregulated by p53 and PTEN in human bladder carcinoma cells.

Although widely deemed as a tumor suppressor gene, the role of B-cell translocation gene 2 (BTG2) in bladder cancer is still inconclusive. We investigated the role and regulatory mechanism of BTG2 in bladder cancer. BTG2 expression in human bladder tissues was determined by RT-qPCR and immunoblotting assays. Expressions of BTG2 and PTEN in bladder carcinoma cells were determined by immunoblotting, RT-qPCR, or reporter assays. The 3 H-thymidine incorporation assay, flow cytometry, and the xenograft animal model were used to determine the cell growth. BTG2 expression was lower in human bladder cancer tissues than normal bladder tissues. Highly differentiated bladder cancer cells, RT4, expressed higher BTG2 than the less-differentiated bladder cancer cells, HT1376 and T24. Overexpression of BTG2 in T24 cells inhibited cell growth in vitro and in vivo. Camptothecin and doxorubicin treatments in RT-4 cells or transient overexpression of p53 into p53-mutant HT1376 cells induced p53 and BTG2 expression. Further reporter assays with site-mutation of p53 response element from GGGAAAGTCC to GGAGTCC within BTG2 promoter area showed that p53-induced BTG2 gene expression was dependent on the p53 response element. Ectopic PTEN overexpression in T24 cells blocked the Akt signal pathway which attenuated cell growth via upregualtion of BTG2 gene expression, while reverse effect was found in PTEN-knockdown RT-4 cells. PTEN activity inhibitor (VO-OHpic) treatment decreased BTG2 expression in RT-4 and PTEN-overexpressed T24 cells. Our results suggested that BTG2 functioned as a bladder cancer tumor suppressor gene, and was induced by p53 and PTEN. Modulation of BTG2 expression seems a promising way to treat human bladder cancer.

Caffeic acid phenethyl ester upregulates N-myc downstream regulated gene 1 via ERK pathway to inhibit human oral cancer cell growth in vitro and in vivo.

SCOPE: Caffeic acid phenethyl ester (CAPE), a bioactive component of propolis, is considered as a new anti-cancer agent. Oral squamous cell carcinoma (OSCC) is the most common oral cancer with unsatisfying survival. N-myc downstream regulated family genes (NDRGs) involve in numerous physiological processes. We investigated the anti-cancer effect of CAPE on OSCC and related mechanisms. METHODS AND RESULTS: Cell proliferation assay, western blot, gene transfection and knockdown, and reporter assay were applied. We showed that CAPE attenuated OSCC cell proliferation and invasion in vitro, and safely and effectively inhibited OSCC cell growth in a xenograft animal model. CAPE treatment induced NDRG1, but not NDRG2 and NDRG3, expression in OSCC cells as determined by western blot, RT-qPCR, and reporter assay. The 5'-deletion assay demonstrated that CAPE increased NDRG1 promoter activity depending on the region of -128 to +46 of the 5'-flanking of NDRG1 gene. NDRG1 gene knockdown attenuated CAPE anti-growth effect on OSCC cells. CAPE activated mitogen-activated protein kinase (MAPK) signaling pathway. The extracellular signal regulated kinase (ERK) inhibitor (PD0325901) and ERK1 knockdown blocked CAPE-induced NDRG1 expression in OSCC cells. CONCLUSION: CAPE activated MAPK signaling pathway and increased NDRG1 expression through phosphorylation of ERK1/2 to repress OSCC cells growth.