A position-dependent silencer plays a major role in repressing alpha-fetoprotein expression in human hepatoma.

Nakabayashi, Hidekazu; Hashimoto, Tomoko; Miyao, Yasuyoshi; Tjong, Kuokoewang; Chan, Jeannie; Tamaoki, Taiki

doi:10.1128/mcb.11.12.5885

Cited by 123 publications

(90 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, relatively low frequency of AFP expression in human HCC may hamper the clinical application. Although serum AFP was elevated in 70% of HCC patients (Nakabayashi et al, 1991), AFP transcripts were not frequently detected with Northern blot analysis as shown in the present study. Di Biscegile et al (1986) reported that nine out of 10 HCC patients showed elevated serum AFP values, but only two out of the 10 HCC specimens were positive for the mRNA with Northern blot analysis.…”

Section: Discussioncontrasting

confidence: 62%

“…MK2.3kb-luc DNA was digested with XhoI/Eco47III to produce the 609-bp fragment-linked firefly luciferase genes (MK0.6-luc). The AFP promoter region (AFP0.2, 212-bp SacI/HindIII fragment) and the enhancer (934-bp SwaI/ EcoRI fragment)-linked AFP promoter region (AFPEn0.2) were prepared from pAF5.1-CAT (Nakabayashi et al, 1991), and they were subcloned into pGL2-basic vector (AFP0.2-luc, AFPEn0.2-luc). The transcriptional activity was measured with the dual luciferase reporter assay system (Promega).…”

Section: Dual Luciferase Assaymentioning

confidence: 99%

“…Our previous studies showed that a 2.3-or a 0.6-kb genomic fragment of the MK gene contained cis-acting elements, which could activate an exogenous gene preferentially in tumours (Miyauchi et al, 2001;Yoshida et al, 2002). Linkage of 0.2-kb AFP promoter and 0.9-kb AFP distal enhancer gave the maximal transcription of a fused reporter gene (Nakabayashi et al, 1991). We thereby examined the transcriptional activity of four kinds of reporter constructs (MK2.3-luc, MK0.6-luc, AFP0.2-luc and AFPEn0.2-luc) in AFP-producing (HuH-7 and PLC/PRF/5) and -nonproducing (HLE and HLF) HCC cell lines (Niwa et al, 1996;Ishikawa et al, 1999), and in non-HCC cell lines (MCF-7 and AsPC-1), which were positive for MK expression (Miyauchi et al, 2001).…”

Section: Transcriptional Activity Of Mk and Afp Promotermentioning

confidence: 99%

“…The a-fetoprotein promoter (AFP) is a representative one to activate an exogenous gene specifically in hepatocellular carcinoma (HCC) (Tamaoki, 2000) and has been applied to targeted gene therapy for HCC (Kanai et al, 1996;Mawatari et al, 1998;Hallenbeck et al, 1999). Precise analysis of the regulatory region of the AFP gene demonstrated that enhancer and silencer elements in the region played a crucial role in the transcription (Nakabayashi et al, 1991) and the silencerdeleted, enhancer-linked AFP promoter showed noticeable therapeutic effects compared with the unmodified AFP promoter (Mawatari et al, 1998).…”

mentioning

confidence: 99%

See 3 more Smart Citations

A promoter region of the midkine gene that is frequently expressed in human hepatocellular carcinoma can activate a suicide gene as effectively as the α-fetoprotein promoter

Tomizawa

Wada

et al. 2003

Br J Cancer

Self Cite

View full text Add to dashboard Cite

A promoter region of the midkine gene that is frequently expressed in human hepatocellular carcinoma can activate a suicide gene as effectively as the a-fetoprotein promoter We examined the expression of the midkine (MK) and a-fetoprotein (AFP) genes in 15 paired human specimens obtained from hepatocellular carcinoma (HCC) and the corresponding noncancerous regions of the same patients. A total of 14 HCC but none of the noncancerous specimens were positive for the MK mRNA. In contrast, three HCC specimens and one corresponding noncancerous sample out of the three AFP-positive HCC cases expressed the AFP gene. A 2.3-kb genomic fragment in the regulatory region of the MK gene could activate a fused reporter gene in both AFP-producing and -nonproducing HCC lines, and the MK fragment-mediated transcriptional activity was comparable to the AFP enhancer-linked AFP promoter in AFP-producing cell lines. The AFP-producing but not AFP-nonproducing HCC cell lines that were transfected with the MK promoter-linked herpes simplex virus-thymidine kinase (HSV-TK) gene became susceptible to a prodrug ganciclovir to a similar degree of the HCC transfected with the enhancer-linked AFP promoter-fused HSV-TK gene. These data suggest that the MK promoter can activate a therapeutic gene preferentially in HCC and is as useful as the AFP promoter in clinical settings.

show abstract

Section: Discussioncontrasting

confidence: 62%

Section: Dual Luciferase Assaymentioning

confidence: 99%

Section: Transcriptional Activity Of Mk and Afp Promotermentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

A promoter region of the midkine gene that is frequently expressed in human hepatocellular carcinoma can activate a suicide gene as effectively as the α-fetoprotein promoter

Tomizawa

Wada

et al. 2003

Br J Cancer

Self Cite

View full text Add to dashboard Cite

show abstract

“…13 To overcome this obstacle, we developed an OV that specifically targeted hepatocellular carcinoma (HCC) cells and improved the safety by replacing the E1A promoter of the ZD55 vector with a liver-cancer specific a-Fetoprotein (AFP) promoter, which was reported to be preferentially expressed in over 70% of human liver cancer patients through transcriptional activation. 14,15 We named this new OV as Ad Á AFP Á D55. In this work, we further inserted IL-24 and TRAIL genes individually into Ad Á AFP Á D55 to generate Ad Á AFP Á D55-IL-24 and Ad Á AFP Á D55-TRAIL, and then evaluated the combined antitumor effects of treatment with these two new oncolytic Ads in vitro and in vivo.…”

Section: Introductionmentioning

confidence: 99%

Gene-viro-therapy targeting liver cancer by a dual-regulated oncolytic adenoviral vector harboring IL-24 and TRAIL

et al. 2011

View full text Add to dashboard Cite

Cancer-targeting gene-viro-therapy is a promising cancer therapeutic strategy that strengthens the antitumor effect of oncolytic viruses by expressing an inserted foreign antitumor gene. To achieve liver cancer targeting and to improve the safety of the ZD55 vector (a widely-used E1B55KD gene-deleted oncolytic adenoviral vector (OV), we previously constructed), we designed a novel OV named Ad Á AFP Á D55 that selectively replicates in hepatocellular carcinoma (HCC) cells by replacing the E1A promoter with the liver-cancer specific a-Fetoprotein (AFP) promoter based on the ZD55 vector. We found that the oncolytic adenoviruses Ad Á AFP Á D55-IL-24 and Ad Á AFP Á D55-TRAIL express tumor-suppressor gene interleukin-24 (IL-24) and tumor necrosis factorrelated apoptosis-inducing ligand (TRAIL), respectively, significantly suppressed the HCC cell growth in vitro by inducing apoptosis by the caspase-8 and mitochondria-dependent caspase-9 signaling pathways. Furthermore, the combined treatment of Ad Á AFP Á D55-IL-24 and Ad Á AFP Á D55-TRAIL showed strong antitumor effects in vivo by significantly inhibiting the tumor growth in HCC HuH-7 cell xenograft mice, and markedly increasing animal survival rate. Therefore, this novel HCC cell-targeting OV carrying tumor-suppressor genes may provide a promising approach for liver cancer gene therapy.

show abstract

Distinct positive and negative regulatory elements control neuronal and hepatic transcription of the human transferrin gene

1996

View full text Add to dashboard Cite

Transferrin (Tf), the iron‐transport protein, plays an essential role in the central nervous system development, plasticity, and aging. As a first step toward elucidating the role of each transcription factor involved in the regulation of Tf gene expression, we have recently shown that similar promoter elements direct cell‐type specific transcription in oligodendrocytes, epithelial choroid plexus cells, and in the neuronal cell line B103. Here we have analyzed the regulatory elements that control the level of expression of the Tf gene in neuronal cells. Transient expression experiments in B103 cells revealed that the −164/+1 promoter region is stimulated by a position‐dependent −1140/−1000 upstream region. DNase I footprinting, gel retardation assays, and antibody reactivity data allowed us to characterize the nuclear factors interacting with this region. The upstream region I‐binding protein (URI‐BP) belongs to the steroid/retinoid receptor family, while URII‐BP is a member of the nuclear factor I (NF‐I) family. Interestingly, no enhancer nor silencer activity is detected in B103 cells. This contrasts with our findings in hepatoma cells, where the activity of the −125/+1 promoter can be repressed by a −1000/−819 upstream negative‐acting region and stimulated by the −3600/−3300 enhancer. We demonstrate that the negative‐acting region presents the characteristics of a silencer that interacts with a nuclear protein present in liver and absent in B103 cells. Similarly, B103 cells lack a nuclear protein able to bind to an essential site of the enhancer. This shows that in B103 cells, the inactivity of the silencer and the enhancer regions results from the absence of at least one essential nuclear protein. © 1996 Wiley‐Liss, Inc.

show abstract

A position-dependent silencer plays a major role in repressing alpha-fetoprotein expression in human hepatoma.

Cited by 123 publications

References 35 publications

A promoter region of the midkine gene that is frequently expressed in human hepatocellular carcinoma can activate a suicide gene as effectively as the α-fetoprotein promoter

A promoter region of the midkine gene that is frequently expressed in human hepatocellular carcinoma can activate a suicide gene as effectively as the α-fetoprotein promoter

Gene-viro-therapy targeting liver cancer by a dual-regulated oncolytic adenoviral vector harboring IL-24 and TRAIL

Distinct positive and negative regulatory elements control neuronal and hepatic transcription of the human transferrin gene

Contact Info

Product

Resources

About