Abstract
Many lines of evidence indicate that the immortalization step is critical for the neoplastic transformation of normal human cells. Once normal human cells have been immortalized, they are relatively easily transformed into neoplastic cells. In order to understand these phenomena, patterns of protein phosphorylation in proliferating normal human fibroblast cell strains and their immortalized cell lines were compared by using two-dimensional polyacrylamide gel electrophoresis. It was found that the expression and phosphorylation levels of the human heat shock protein 27 (HSP27) were predominantly downregulated in the immortalized cells compared with those in their normal counterparts. In the normal cells, HSP27 expression and phosphorylation were markedly increased by physiological and nonphysiological stresses, such as serum addition, treatment with a carcinogenic agent like 4-nitroquinoline-1-oxide, and a high osmotic pressure. This may be a normal defense against acute changes of cellular environment and cytotoxic effects. However, these stresses had no effects on the expression and phosphorylation of HSP27 in the immortalized cells. These results suggest that an abnormal regulation of HSP27 expression and phosphorylation may be one of the reasons for easy neoplastic transformation of the immortalized cells by the treatment with carcinogenic agents.
| Original language | English |
|---|---|
| Pages (from-to) | 155-160 |
| Number of pages | 6 |
| Journal | Electrophoresis |
| Volume | 22 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2001 |
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Keywords
- Heat shock protein 27
- Human fibroblasts
- Immortalization
- Two-dimensional polyacrylamide gel electrophoresis
ASJC Scopus subject areas
- Clinical Biochemistry
Cite this
Identification of a phosphoprotein that is downregulated in immortalized human fibroblasts. / Sakaguchi, Masakiyo; Miyazaki, Masahiro; Kondo, Tadashi; Tsuji, Toshiya; Kouchi, Hirosuke; Namba, Masayoshi.
In: Electrophoresis, Vol. 22, No. 1, 2001, p. 155-160.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Identification of a phosphoprotein that is downregulated in immortalized human fibroblasts
AU - Sakaguchi, Masakiyo
AU - Miyazaki, Masahiro
AU - Kondo, Tadashi
AU - Tsuji, Toshiya
AU - Kouchi, Hirosuke
AU - Namba, Masayoshi
PY - 2001
Y1 - 2001
N2 - Many lines of evidence indicate that the immortalization step is critical for the neoplastic transformation of normal human cells. Once normal human cells have been immortalized, they are relatively easily transformed into neoplastic cells. In order to understand these phenomena, patterns of protein phosphorylation in proliferating normal human fibroblast cell strains and their immortalized cell lines were compared by using two-dimensional polyacrylamide gel electrophoresis. It was found that the expression and phosphorylation levels of the human heat shock protein 27 (HSP27) were predominantly downregulated in the immortalized cells compared with those in their normal counterparts. In the normal cells, HSP27 expression and phosphorylation were markedly increased by physiological and nonphysiological stresses, such as serum addition, treatment with a carcinogenic agent like 4-nitroquinoline-1-oxide, and a high osmotic pressure. This may be a normal defense against acute changes of cellular environment and cytotoxic effects. However, these stresses had no effects on the expression and phosphorylation of HSP27 in the immortalized cells. These results suggest that an abnormal regulation of HSP27 expression and phosphorylation may be one of the reasons for easy neoplastic transformation of the immortalized cells by the treatment with carcinogenic agents.
AB - Many lines of evidence indicate that the immortalization step is critical for the neoplastic transformation of normal human cells. Once normal human cells have been immortalized, they are relatively easily transformed into neoplastic cells. In order to understand these phenomena, patterns of protein phosphorylation in proliferating normal human fibroblast cell strains and their immortalized cell lines were compared by using two-dimensional polyacrylamide gel electrophoresis. It was found that the expression and phosphorylation levels of the human heat shock protein 27 (HSP27) were predominantly downregulated in the immortalized cells compared with those in their normal counterparts. In the normal cells, HSP27 expression and phosphorylation were markedly increased by physiological and nonphysiological stresses, such as serum addition, treatment with a carcinogenic agent like 4-nitroquinoline-1-oxide, and a high osmotic pressure. This may be a normal defense against acute changes of cellular environment and cytotoxic effects. However, these stresses had no effects on the expression and phosphorylation of HSP27 in the immortalized cells. These results suggest that an abnormal regulation of HSP27 expression and phosphorylation may be one of the reasons for easy neoplastic transformation of the immortalized cells by the treatment with carcinogenic agents.
KW - Heat shock protein 27
KW - Human fibroblasts
KW - Immortalization
KW - Two-dimensional polyacrylamide gel electrophoresis
UR - http://www.scopus.com/inward/record.url?scp=0035162825&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035162825&partnerID=8YFLogxK
U2 - 10.1002/1522-2683(200101)22:1<155::AID-ELPS155>3.0.CO;2-L
DO - 10.1002/1522-2683(200101)22:1<155::AID-ELPS155>3.0.CO;2-L
M3 - Article
C2 - 11197166
AN - SCOPUS:0035162825
VL - 22
SP - 155
EP - 160
JO - Electrophoresis
JF - Electrophoresis
SN - 0173-0835
IS - 1
ER -