Growth inhibition of keratinocytes by TGF-β and the impaired signaling in cancer cells
| Project/Area Number |
11670232
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Experimental pathology
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| Research Institution | Japanese Foundation for Cancer Research |
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Principal Investigator |
KATO Mitsuyasu JAPANESE FOUNDATION FOR CANCER RESEARCH CANCER INSTITUTE, DEPARTMENT OF BIOCHEMISTRY ASSOCIATE MEMBER, 癌研究所・生化学部, 主任研究員 (20194855)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1999: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Smad / TGF-β / Bone morphogenetic protein / Cancer / Growth inhibition / invasion / SMAD / トランスフォーミング増殖因子 / 癌 |
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| Research Abstract |
1. Identification of a TGF-β responsive element in the c-myc promoter :
A TGF-β responsive element was identified in the c-myc promoter. This element had an consensus sequence with TGF-β inhibitory element (TIE) which was identified in the mouse stromelysin gene. TIE in the c-myc promoter partially overlapped an E2F site and bound TGF-β-regulated Smad within 1 h after stimulation by TGF-β.
2. Pursuit of nuclear proteins responsible for impaired c-myc-response to TGF-β in squamous cell carcinoma cell lines :
Transcriptional activity of the c-myc promoter was not suppressed by TGF-β in several squamous cell carcinoma cell lines. We compared nuclear proteins which bound to the TIE/E2F oligonucleotides between cancer cells and a keratinocyte cell line (HaCaT), and found several protein bands enhanced or lost in cancer cells by DNA-affinity precipitation followed by SDS-PAGE.
3. Blocking of Smad pathway confers invasive growth activity on HaCaT cells :
We have established a 3-dimensional culture
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method exhibiting stromal invasion of squamous cell carcinoma cell lines. Using this method, HaCaT cells were shown to obtain invasive activity by expression of dominant negative Smad3 (Smad3D407E). There was good correlation between expression levels of Smad3D407E and obtained invasive activities. We screened the differentially expressed genes induced by Smad3D407E in HaCaT cells by DNA chip analyses to search the target genes of Smad pathway which contribute to acquire invasive activity.
4. BMP signaling and the target gene :
We have cloned mouse Smad6 genomic clones, and identified a BMP-responsive element in the Smad6 promoter. The BMP-responsive element (GC2) had a GC-rich sequence similar to a Madresponsive element in Drosophila. BMP-regulated Smads and Co-Smad directly bound GC2. R-Smad enhanced transcription of Smad6 from GC2 element. On the other hand, Co-Smad suppressed the transcriptional activity.
BMP-2/4 and BMP-6/7 belong to different subfamily and exhibit cooperative effects in some biological assays. BMP-2/4 and BMP-6/7 preferentially bound ALK-3/6 and ALK-2, respectively. Expression of constitutively active forms of these receptors also gave additional effects and these receptors were suggested to activate at least partially distinct signaling pathways. Less
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Report
(3 results)
Research Products
(15 results)
