Differential effects of protein kinase A sub-units on Chinese-hamster-ovary cell cycle and proliferation.
It has been shown that a marked increase in the levels of RI alpha sub-units and a decrease in RII beta sub-unit levels correlate with neoplastic transformation or with the mitogenic response of normal cells to hormones and growth factors. The selective down-regulation of RI alpha and the following induction of RII beta determine cell-growth arrest and differentiation of several cancer cells. To directly address the question whether the 2 protein-kinase-A(PKA) isoforms play different roles in the control of proliferation and cell-cycle distribution, we introduced and over-expressed the different PKA sub-units in Chinese-hamster-ovary (CHO) cells via retroviral-vector-mediated gene transfer. Whereas CHO cells treated with RI alpha anti-sense oligodeoxynucleotides were growth arrested and accumulated in the G0/G1 phases of the cell cycle, infection of CHO cells with a retroviral vector in order to over-express RI alpha determined growth advantages in monolayer conditions and substantially increased their cloning efficiency in soft agar. These events correlated with a sustained percentage of cells in S phase induced by RI alpha over-expression in the infected cells. In contrast, CHO cells infected with retroviral vectors over-expressing either a RII beta sub-unit or a C alpha catalytic sub-unit of PKA exhibited growth arrest within a few days of culture and accumulated in the G2-M phase of the cell cycle. The results of our study demonstrate that the different PKA sub-units play different and specific roles in the control of cell growth and cell-cycle distribution.
Tortora
G
G
Cattedra di Oncologia Medica, Facoltà di Medicina e Chirurgia, Università di Napoli Federico II, Italy.
Pepe
S
S
Bianco
C
C
Damiano
V
V
Ruggiero
A
A
Baldassarre
G
G
Corbo
C
C
Cho-Chung
Y S
YS
Bianco
A R
AR
Ciardiello
F
F
D000818:Animals; D017209:Apoptosis; D016466:CHO Cells / Q000166:cytology*; D002453:Cell Cycle / Q000502:physiology*; D002455:Cell Division / Q000502:physiology*; D006224:Cricetinae; D054757:Cyclic AMP-Dependent Protein Kinase RIIbeta Subunit; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000502:physiology; D005434:Flow Cytometry; D015870:Gene Expression; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D012190:Retroviridae / Q000235:genetics
D054757:Cyclic AMP-Dependent Protein Kinase RIIbeta Subunit; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D016376:Oligonucleotides, Antisense; D017868:Cyclic AMP-Dependent Protein Kinases