Enhanced expression of cyclin-dependent kinase inhibitor in apoptosis of androgen-independent prostatic cancer cell line induced by calcium ionophore.
In order to examine the relationship between apoptosis of androgen-independent prostatic cancer cells and cell cycle-associated proteins, TSU-pr1 human prostatic cancer cells were chronically exposed in vitro to the calcium ionophore ionomycin to sustain an elevation in their intracellular free calcium concentration. Temporal analysis demonstrated that the death of these cells does not require cell proliferation and involves fragmentation of genomic DNA into nucleosome sized pieces. Morphological analysis demonstrated that this death process is via apoptosis. During the apoptotic process induced by ionomycin, expression of cyclin-dependent kinase inhibitor p27Kip1 increased. Flow cytometric analysis showed that the treatment resulted in a block in G0/G1 of the cell cycle. These results demonstrate that even nonproliferating androgen-independent prostatic cancer cells can be induced to undergo apoptosis if a modest elevation in the intracellular free calcium is sustained for a sufficient time. p27Kip1 protein is a candidate for the cell cycle regulator in ionomycin-treated TSU-pr1 cells.
Furuya
Y
Y
Department of Urology, School of Medicine, Chiba University, Japan.
Ohta
S
S
Yasuda
K
K
Ito
H
H
D000728:Androgens / Q000502:physiology; D017209:Apoptosis; D002118:Calcium / Q000502:physiology*; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D016213:Cyclins / Q000378:metabolism*; D053938:DNA Fragmentation / Q000187:drug effects; D004273:DNA, Neoplasm / Q000737:chemistry; D006801:Humans; D015759:Ionomycin / Q000494:pharmacology*; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000473:pathology*; D013997:Time Factors; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
D000728:Androgens; C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004273:DNA, Neoplasm; D008869:Microtubule-Associated Proteins; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D015759:Ionomycin; D002118:Calcium