Expression of pRB, cyclin/cyclin-dependent kinases and E2F1/DP-1 in human tumor lines in cell culture and in xenograft tissues and response to cell cycle agents.
OBJECTIVE
Cell cycle regulatory components are interesting targets for cancer therapy. Expression of pRb, cyclin D1, cdk4, cyclin E, cdk2, E2F1 and DP-1 was determined in MCF-7 and MDA-MB-468 breast carcinoma cells, H460 and Calu-6 non-small cell lung carcinoma cells, H82 and SW2 small cell lung carcinoma cells, HCT116 and HT29 colon carcinoma cells and LNCaP and DU-145 prostate carcinoma cells.


METHODS
For Western blotting, the ratio with actin expression was used to normalize the data; all lines were run on the same gels.


RESULTS
In cell culture, pRb was not detected in MB-468 and H82 was low in SW2 and DU-145 and highest in HCT116; in tumors, pRb was not detected in MB-468, H82, SW2, and DU-145 and was highest in LNCaP and Calu-6. Cyclin D1 was not detected in SW2 cells in culture, was low in MB-468 and H82, and was highest in LNCaP and H460; in tumors, cyclin D1 was low in MB-468, H460, SW2 and DU 145, and was highest in LNCaP. In cell culture, cdk4 was lowest in Calu-6, HCT116, HT29 and DU-145 and highest in H82 and SW2; in tumors, cdk4 was low in MCF-7, MB-468, H460, Calu-6 and HCT116 and was very high in the SW2. Expression of cyclin E was very low in MCF-7 and HT29 and high in H460 in culture and was very low in MCF-7, H460, Calu-6, H82, HT29 and DU-145 in tumors and high in HCT116 and LNCaP. In cell culture, E2F1 was lowest in MB-468, Calu-6, HT29 and DU-145 cells and highest in LNCaP cells; in tumors, E2F1 was lowest in MCF-7, MB-468 and Calu-6 and highest in LNCaP. In cell culture, DP-1 was lowest in MB-468, HCT116 and HT29 and highest in SW2. The MCF-7 and MB-468 lines were most resistant to flavopiridol and olmoucine and the H460 and Calu-6 lines were most resistant to genistein. The SW2 tumor was most responsive to flavopiridol and olomoucine.


CONCLUSIONS
There is a high degree of variability in the expression of cell cycle components in human tumor cell lines, resulting in complexity in predicting response to cell cycle directed agents.
Lu
K
K
Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN 46285, USA.
Shih
C
C
Teicher
B A
BA
D000368:Aged; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D015153:Blotting, Western; D002148:Calmodulin-Binding Proteins / Q000096:biosynthesis*; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins; D002470:Cell Survival / Q000187:drug effects; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D016213:Cyclins / Q000096:biosynthesis*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D006801:Humans; D007701:Kinetin; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008875:Middle Aged; D009368:Neoplasm Transplantation; D010880:Piperidines / Q000494:pharmacology; D010940:Plant Proteins / Q000096:biosynthesis*; D011687:Purines / Q000494:pharmacology; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000096:biosynthesis*; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D002148:Calmodulin-Binding Proteins; D018797:Cell Cycle Proteins; D016213:Cyclins; C115911:EDF1 protein, human; C485470:Edf1 protein, mouse; D004791:Enzyme Inhibitors; D005419:Flavonoids; D010880:Piperidines; D010940:Plant Proteins; D011687:Purines; C107938:RRB1 protein, Zea mays; C493735:TFDP1 protein, human; C493736:Tfdp1 protein, mouse; D050680:Transcription Factor DP1; D014157:Transcription Factors; C077990:alvocidib; C090046:olomoucine; D019833:Genistein; D018844:Cyclin-Dependent Kinases; D007701:Kinetin