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Open Access Research

PRIMA-1 increases cisplatin sensitivity in chemoresistant ovarian cancer cells with p53 mutation: a requirement for Akt down-regulation

Noriko Kobayashi12, Mohammadreza Abedini13, Noriaki Sakuragi2 and Benjamin K Tsang14*

Author Affiliations

1 Department of Obstetrics & Gynecology and Cellular & Molecular Medicine, University of Ottawa; Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa K1H 8L6, Canada

2 Department of Gynecology, Hokkaido University Graduate School of Medicine and School of Medicine, Sapporo, Japan

3 Cellular and Molecular Medicine Research Center, Department of Physiology and Pharmacology, Birjand University of Medical Sciences, Birjand, Iran

4 World Class University (WCU) Biomodulation Major, Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea

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Journal of Ovarian Research 2013, 6:7  doi:10.1186/1757-2215-6-7

Published: 26 January 2013

Abstract

Background

Since ovarian cancer is associated with high frequency of p53 mutation, the availability of

    p
53
    r
eactivation and
    i
nduction of
    m
assive
    a
poptosis (PRIMA-1) offers a possible new therapeutic strategy for overcoming this devastating disease. Although Akt activation is believed to be a determinant in chemoresistance in ovarian cancer, whether Akt plays a role in regulating the effectiveness of PRIMA-1 in sensitizing chemoresistant ovarian cancer cells with p53 mutation to cisplatin (CDDP), remains to be determined.

Methods

In the present studies, we examined the influence of Akt down-regulation following dominant-negative (DN-Akt) expression on the ability of PRIMA-1 (0–10 μM) to facilitate CDDP (0–10 μM)-induced apoptosis in p53-mutated chemoresistant ovarian cancer cells (A2780cp).

Results

Apoptosis rate was significantly higher at the combined treatment of low PRIMA-1 concentrations (0.156 - 0.938 μM) plus CDDP (10 μM) in the DN-Akt groups than control (p<0.001). Apoptosis in cells treated with PRIMA-1 (0.156 μM) and CDDP treatment (10 μM) was significantly suppressed by p53-siRNA. PRIMA-1 increased phospho-p53 (Ser15) content in Akt down-regulated cells treated with CDDP.

Conclusions

These results demonstrate that PRIMA-1 can sensitize chemoresistant ovarian cancer cells with p53 mutation to CDDP when Akt is down-regulated, and the action of PRIMA-1 is associated with p53 activation. Our findings raise the possibility that PRIMA-1 may be useful candidate for adjuvant therapy with CDDP in chemoresistant ovarian cancer with p53 mutation when Akt is down-regulated.

Keywords:
PRIMA-1; Chemoresistance; Ovarian cancer; Akt; p53; Cisplatin