Elevated expression of calcium-binding protein p9Ka is associated with increasing malignant characteristics of rat prostate carcinoma cells

Int J Cancer. 1997 May 29;71(5):832-7. doi: 10.1002/(sici)1097-0215(19970529)71:5<832::aid-ijc22>3.0.co;2-8.


Northern and Western blotting techniques were used to study expression of the mRNA and corresponding protein product of the S100-related calcium-binding molecule p9Ka in 6 different metastatic cell lines of the Dunning R3327 rat prostate cancer model. In cells with the lowest metastatic capability (G cells), p9Ka mRNA was barely detectable. In 2 weakly metastatic cell lines (AT-1 and AT-2), p9Ka transcript amounts were, respectively, 6.29 +/- 0.74 and 5.55 +/- 1.11 times that detected in the G cells. In 3 highly metastatic cell lines (AT-3, MAT-LyLu and MAT-Lu), the amounts of p9Ka mRNA were, respectively, 12.85 +/- 2.82, 13.06 +/- 1.69 and 11.62 +/- 1.81 times that expressed in the G cells. Western blot analyses detected no p9Ka protein in the G cells. The amounts of p9Ka protein expressed by tumour cells of intermediate metastatic capability (AT-1 and AT-2) were 3.4 +/- 1.3 microg and 3.3 +/- 1.4 microg, respectively, per 1 x 10(6) cells. The amounts of p9Ka protein expressed by the tumour cells of highest metastatic capability (AT-3, MAT-LyLu and MAT-Lu) were 8.3 +/- 1.1 microg, 8.7 +/- 1.6 microg and 9.6 +/- 1.7 microg, respectively, per 1 x 10(6) cells. Our data reveal a direct association between the elevated expression of mRNA and the p9Ka protein amounts and the increased metastatic capability of individual prostatic cancer cell lines. We suggest that calcium-binding protein p9Ka may play an important role in the metastatic behaviour of rat prostate cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Northern
  • Blotting, Western
  • Calcium-Binding Proteins / genetics*
  • DNA Probes
  • Gene Expression*
  • Male
  • Neoplasm Metastasis
  • Prostatic Neoplasms / metabolism*
  • Prostatic Neoplasms / pathology*
  • RNA, Messenger / analysis
  • Rats
  • S100 Calcium-Binding Protein A4
  • S100 Proteins
  • Tumor Cells, Cultured


  • Calcium-Binding Proteins
  • DNA Probes
  • RNA, Messenger
  • S100 Calcium-Binding Protein A4
  • S100 Proteins
  • S100a4 protein, rat