Effect of p27(KIP1) on cell cycle and apoptosis in gastric cancer cells.
OBJECTIVE
To elucidate the effect of p27(KIP1) on cell cycle and apoptosis regulation in gastric carcinoma cells.


METHODS
The whole length of p27(KIP1) cDNA was transfected into human gastric cancer cell line SCG7901 by lipofectamine. Expression of p27(KIP1) protein or mRNA was analyzed by Western blot and RNA dot blotting, respectively. Effect of p27(KIP1) on cell growth was observed by MTT assay and anchorage-independent growth in soft agar. Tumorigenicity in nude mice was used to assess the in vivo biological effect of p27(KIP1). Flow cytometry, TUNEL, and electron microscopy were used to assess the effect of p27(KIP1) on cell cycle and apoptosis.


RESULTS
Expression of p27(KIP1) protein or mRNA increased evidently in SCG7901 cells transfected with p27(KIP1). The cell growth was reduced by 31% at 48 h after induction with zinc determined by cell viability assay. The alteration of cell malignant phenotype was evidently indicated by the loss of anchorage-independent growth ability in soft agar. The tumorigenicity in nude mice was reduced evidently (0.55+/-0.14 cm vs 1.36+/-0.13 cm, P<0.01). p27(KIP1) overexpression caused cell arrest with 36% increase (from 33.7% to 69.3%, P<0.01) in G1 population. Prolonged p27(KIP1) expression induced apoptotic cell death reflected by pre-G1 peak in the histogram of FACS, which was also confirmed by TUNEL assay and electron microscopy.


CONCLUSIONS
p27(KIP1) can prolong cell cycle in G1 phase and lead to apoptosis. p27(KIP1) may be a good candidate for cancer gene therapy.
Zheng
Jian-Yong
JY
Department of Gastrointestinal Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi Province, China. zhengjy2000@sohu.com
Wang
Wei-Zhong
WZ
Li
Kai-Zong
KZ
Guan
Wen-Xian
WX
Yan
Wei
W
D000818:Animals; D017209:Apoptosis / Q000235:genetics; D002453:Cell Cycle / Q000235:genetics; D045744:Cell Line, Tumor; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000235:genetics*; D015870:Gene Expression; D015316:Genetic Therapy; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology* / Q000628:therapy; D014162:Transfection; D014183:Transplantation, Heterologous
C436291:CDKN1B protein, human; D047908:Intracellular Signaling Peptides and Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27