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Updated: Aug 9, 2026
Heterotypic Three-dimensional In Vitro Modeling of Stromal-Epithelial Interactions During Ovarian Cancer Initiation and Progression
Published on: August 28, 2012
Introduction of wild-type p53 in a human ovarian cancer cell line not expressing endogenous p53
F Vikhanskaya1, E Erba, M D'Incalci
1Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
Abstract:
Utilizing a temperature sensitive p53 mutant (pLTRp53cGval135) which expresses mutant p53 at 37 degrees C and a wild-type like p53 at 32 degrees C, we transfected a human ovarian cancer cell line (SKOV3) which does not express endogenous p53. Among the different clones obtained, we selected three clones. Two were obtained from simultaneous transfection of p53 and neomycin resistance expression plasmids (SK23a and SK9), the other was obtained from transfection experiments utilizing the neomycin resistance gene only (SKN). Introduction of mutant p53 did not alter the morphology or growth characteristics of this ovarian cancer cell line. Upon shifting to the permissive temperature, a dramatic change in morphology and growth rate was observed in SK23a and SK9 cells that is associated with the presence of a wild-type like p53. SKN and SKOV3 cells maintained at 32 degrees C did not change morphology and only slightly reduced proliferation. Both SK23a and SK9 cells did not show evidence of apoptosis when measured up to 72 hours of maintenance at 32 degrees C. In contrast to what observed in other cell lines, SK23a and SK9 cells maintained at 32 degrees C were not blocked in G1, but they were accumulated in G2-M. This accumulation was transient and could be due either to a blockade or to a delay in the G2 progression. No down-regulation of c-myc was observed in p53 expressing clones when shifted to the permissive temperature. In these conditions gadd45 mRNA expression was highly stimulated in SK9 and SK23a cells but not in SKN cells. In both clones Gas1 mRNA was not detected either at 37 degrees C or 32 degrees C. This system represents a new and useful model for studying the effect of the absence of p53 (SKOV3 or SKN), presence of mutated p53 (SK23a and SK9 kept at 37 degrees C) or wild type p53 (SK23a and SK9 kept at 32 degrees C) on the mechanism of response of cancer cells to DNA damaging agents.
Insights
This study developed a novel model using ovarian cancer cells to investigate the tumor suppressor protein p53. The findings reveal how wild-type p53 influences cancer cell growth and gene expression.
Area of Science:
- Molecular Biology
- Cancer Research
- Cell Biology
Background:
- The tumor suppressor protein p53 plays a critical role in cellular responses to DNA damage.
- Understanding p53's function is crucial for developing effective cancer therapies.
- Ovarian cancer cell lines lacking endogenous p53 provide a valuable system for studying p53's effects.
Purpose of the Study:
- To establish a novel cellular model system for investigating the distinct roles of mutant and wild-type p53.
- To analyze the impact of p53 status on ovarian cancer cell morphology, proliferation, and cell cycle progression.
- To examine the expression of key genes (c-myc, gadd45, Gas1) in response to p53 modulation.
Main Methods:
- Transfection of SKOV3 human ovarian cancer cells with a temperature-sensitive p53 mutant (pLTRp53cGval135).
- Selection and characterization of transfected clones expressing either mutant p53, wild-type like p53, or no p53.
- Analysis of cell morphology, growth rate, apoptosis, cell cycle distribution (G1, G2-M), and gene expression (c-myc, gadd45, Gas1) at different temperatures.
Main Results:
- Introduction of mutant p53 did not alter SKOV3 cell characteristics, while wild-type like p53 induced significant changes in morphology and growth rate.
- Cells expressing wild-type like p53 accumulated transiently in the G2-M phase, unlike G1 arrest observed in other cell lines.
- gadd45 mRNA expression was significantly stimulated by wild-type like p53, while c-myc and Gas1 expression remained unaffected.
Conclusions:
- The developed temperature-sensitive p53 system in SKOV3 cells offers a unique model to study p53 absence, mutant p53, and wild-type p53.
- Wild-type p53 influences ovarian cancer cell cycle progression, specifically causing G2-M accumulation and upregulating gadd45.
- This model facilitates research into cancer cell responses to DNA damage under varying p53 conditions.
