Paclitaxel and SN-38 overcome cisplatin resistance of ovarian cancer cell lines by down-regulating the influx and efflux system of cisplatin

Yuuki Komuro, Yasuhiro Udagawa, Nobuyuki Susumu, Daisuke Aoki, Tetsuro Kubota, Shiro Nozawa

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16 Citations (Scopus)


Cisplatin (DDP) is one of the key drugs used to treat patients with ovarian cancer, although resistance to DDP can occur. Paclitaxel and SN-38 (an active metabolite of irinotecan (CPT-11)) are two drugs that are effective in patients with DDP-resistant ovarian cancer. To study how these drugs may overcome the intrinsic and/or acquired resistance of cancer cells to DDP, we investigated the effect of a combination of DDP with paclitaxel and a combination of DDP with SN-38 on three ovarian cancer cell lines, RTSG (intrinsically resistant cell line), KF (DDP-sensitive cell line), and KFra (acquired resistant cell line obtained from KF). We found that these combinations showed additive to synergistic antitumor activity. A time-dependent platinum (Pt) accumulation was observed in the DDP-sensitive KF cell line, while a decrease occurred in the KFra cell line. Little accumulation was observed in RTSG. Intracellular Pt accumulation was increased in all three cell lines by exposure to paclitaxel or SN-38. Ouabain, a Na+, K+-ATPase inhibitor, decreased Pt accumulation in KF and KFra cell lines and inhibited the paclitaxel- and SN-38-induced increases in Pt accumulation in these cell lines. When we assessed the mRNA levels of the multidrug resistance-associated protein (MRP), which may be an efflux pump for DDP, the combination of paclitaxel or SN-38 with DDP down-regulated these levels, which are up-regulated by DDP alone. These results suggest that paclitaxel and SN-38 overcome DDP resistance of ovarian cell lines by controlling intracellular accumulation of DDP via both the influx and efflux systems.

Original languageEnglish
Pages (from-to)1242-1250
Number of pages9
JournalJapanese Journal of Cancer Research
Issue number11
Publication statusPublished - 2001
Externally publishedYes


  • Cisplatin
  • Multidrug resistance-associated protein
  • Paclitaxel
  • Resistance
  • SN-38

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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