Effects of p21cip1/waf1 overexpression on growth, apoptosis and differentiation in human colon carcinoma cells.
The cyclin-dependent kinase inhibitor p21cip1/waf1 negatively regulates the progression of cell cycle and the potential usefulness of p21cip1/waf1 gene is proposed in gene therapy. However, studies have demonstrated a protective role of p21cip1/waf1 against apoptosis and little is known about effects of ectopic expression of p21cip1/waf1 on differentiation of colon cancer cells. In the present study, we found diffuse p21cip1/waf1 expression in only a few clinical samples of colorectal cancer with wild-type p53 gene. To explore the role of p21cip1/waf1 in cell growth, apoptosis and differentiation, we constitutively overexpressed p21cip1/waf1 in HT29 colon carcinoma cells. Ectopic overexpression of p21cip1/waf1 was associated with inhibition of CDK2-associated kinase activity, indicating the functionality of the introduced p21cip1/waf1 gene. Overexpression of p21cip1/waf1 caused an appreciable growth inhibition in monolayer and soft agar cultures and it significantly reduced sodium butyrate- but not 5-fluorouracil-induced apoptosis. p21cip1/waf1 overexpressing cells exhibited marked decrease of intestinal differentiation when assayed with intestinal alkaline phosphatase. Our findings suggest that introduction of p21cip1/waf1 gene into colon cancer cells may be useful for inhibiting cell growth but caution should be taken regarding the increased resistance to certain apoptosis-inducing agents and dysregulation of endogenous p21cip1/waf1-mediated differentiation process.
Izawa
Hikaru
H
Department of Surgery and Clinical Oncology, Graduate School of Medicine, Osaka University, Japan.
Yamamoto
Hirofumi
H
Damdinsuren
Bazarragchaa
B
Ikeda
Kimimasa
K
Tsujie
Masaki
M
Suzuki
Rei
R
Kitani
Kotaro
K
Seki
Yosuke
Y
Hayashi
Taro
T
Takemasa
Ichiro
I
Ikeda
Masataka
M
Ohue
Masayuki
M
Sekimoto
Mitsugu
M
Monden
Takushi
T
Monden
Morito
M
D000362:Agar / Q000737:chemistry; D000469:Alkaline Phosphatase / Q000378:metabolism; D017209:Apoptosis; D015153:Blotting, Western; D002087:Butyrates / Q000494:pharmacology; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004252:DNA Mutational Analysis; D005434:Flow Cytometry; D005472:Fluorouracil / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D020128:Inhibitory Concentration 50; D058610:Isobutyrates; D009154:Mutation; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D002087:Butyrates; C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D058610:Isobutyrates; D016159:Tumor Suppressor Protein p53; C020380:isobutyric acid; D000362:Agar; D000469:Alkaline Phosphatase; D005472:Fluorouracil