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p53 antisense oligonucleotide inhibits growth of human colon tumor and normal cell lines
Y Hirota1, T Horiuchi, K Akahane
1New Product Research Laboratories IV, Daiichi Pharmaceutical Co., Ltd., Tokyo.
Abstract:
We examined the relationship between the expression of mutant p53 proteins and tumor cell growth using a p53 antisense oligonucleotide (5'-CCCTGCTCCCCCCTGGCTCC-3'). The oligonucleotide inhibited the growth of three human colon tumor cell lines (DLD-a, SW620 and WiDr), which produce only mutant p53 proteins with different mutation sites. Treatment of DLD-1 cells with the p53 antisense oligonucleotide caused a decrease in the level of p53 mutant protein. Synthesis of DNA in DLD-1 and SW620 cells was inhibited more potently than that of RNA or protein after antisense treatment. Furthermore, these cells were accumulated in the S phase when DNA synthesis was inhibited. Meanwhile, the antisense oligonucleotide also inhibited the growth of three human normal cell lines (WI-38, TIG-1 and Intestine 407). While treatment of WI-38 and TIG-1 cells with the antisense oligonucleotide inhibited synthesis of DNA more potently than that of RNA or protein, these normal cells were accumulated in the G0/G1 phase. These results suggest that p53 proteins, either with or without mutation, play a pivotal role in the growth of tumor and normal cells, but that mutant and wild-type p53 proteins may function differently in cell growth.
Insights
A p53 antisense oligonucleotide inhibited both tumor and normal cell growth. Mutant p53 proteins play a key role in tumor cell proliferation, potentially differing from wild-type p53 functions.
Area of Science:
- Molecular Biology
- Cancer Research
- Cell Biology
Background:
- The p53 protein is a critical regulator of cell growth and tumor suppression.
- Mutations in the p53 gene are common in human cancers, leading to the production of mutant p53 proteins.
- The precise role of mutant p53 proteins in tumor cell proliferation and their distinction from wild-type p53 function remain areas of active investigation.
Purpose of the Study:
- To investigate the role of mutant p53 protein expression in tumor cell growth.
- To determine the effects of inhibiting p53 expression using antisense oligonucleotides on both tumor and normal cell lines.
- To elucidate potential differences in the function of mutant versus wild-type p53 proteins in cell cycle regulation.
Main Methods:
- Utilized a specific p53 antisense oligonucleotide (5'-CCCTGCTCCCCCCTGGCTCC-3') to target p53 mRNA.
- Assessed the impact of the oligonucleotide on the growth of human colon tumor cell lines (DLD-1, SW620, WiDr) and normal cell lines (WI-38, TIG-1, Intestine 407).
- Quantified p53 mutant protein levels, DNA/RNA/protein synthesis, and cell cycle distribution (G0/G1, S, G2/M phases) following antisense treatment.
Main Results:
- The p53 antisense oligonucleotide significantly inhibited the growth of all tested human colon tumor cell lines expressing mutant p53.
- Antisense treatment led to decreased mutant p53 protein levels and potent inhibition of DNA synthesis in tumor cells, causing S-phase arrest.
- Normal cell lines also exhibited growth inhibition and DNA synthesis reduction, but with accumulation in the G0/G1 phase, suggesting differential p53 roles.
Conclusions:
- p53 proteins, irrespective of mutation status, are essential for the proliferation of both tumor and normal cells.
- Mutant p53 proteins appear to play a distinct and pivotal role in promoting tumor cell growth compared to wild-type p53.
- Targeting p53 expression with antisense oligonucleotides demonstrates therapeutic potential, with differential effects on tumor versus normal cell cycle progression.