Possible role of placental leucine aminopeptidase in the antiproliferative effect of oxytocin in human endometrial adenocarcinoma

Yuka Suzuki, Kiyosumi Shibata, Fumitaka Kikkawa, Hiroaki Kajiyama, Kazuhiko Ino, Seiji Nomura, Masafumi Tsujimoto, Shigehiko Mizutani

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30 Citations (Scopus)


Purpose: Oxytocin (OT) was reported to inhibit the proliferation of various neoplastic tissues and cells, however, the regulation system remains unclear. This study examined the role of OT and its regulatory ability in endometrial adenocarcinoma. Experimental Design: To investigate the possible function of placental leucine aminopeptidase (P-LAP) in endometrial adenocarcinoma, we transfected P-LAP cDNA into A-MEC cells, showing the lowest enzyme activity of P-LAP. Also we examined P-LAP protein expression in human endometrial adenocarcinoma. Results: We demonstrated the presence of P-LAP, which is identical to cystine aminopeptidase as oxytocinase, in human endometrial adenocarcinoma tissues and found that the expression of P-LAP increase with advances in the grade. Exposure of endometrial adenocarcinoma cell lines to OT caused dose- and time-dependent inhibition of growth. Treatment with 10-7 M OT for 72 h reduced cell growth by 62, 25, and 30% in A-MEC, HEC1A, and Ishikawa cells, respectively. P-LAP-transfectant cells not only partially recovered from OT-induced growth inhibition but also showed a higher growth rate than parental cells under condition without OT. An OT receptor antagonist and a protein kinase A inhibitor blocked OT-induced growth inhibition in A-MEC and A-MEC-pc cells but not in A-MEC-LAP cells. Conclusions: These findings suggested that P-LAP might be functionally positive on carcinoma cell growth by degrading suppressive peptides such as OT.

Original languageEnglish
Pages (from-to)1528-1534
Number of pages7
JournalClinical Cancer Research
Issue number4
Publication statusPublished - 01-04-2003
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research


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