Growth arrest and induction of apoptosis in breast cancer cells by antisense depletion of protein kinase A-RI alpha subunit: p53-independent mechanism of action.
The enhanced expression of the RI alpha subunit of cyclic AMP-dependent protein kinase type 1 (PKA-1) has been correlated with cancer cell growth. We have investigated the effects of sequence-specific inhibition of RI alpha gene expression on the growth of MCF-7 human breast cancer cells. We report that RI alpha antisense treatment results in a reduction in RI alpha expression at both mRNA and protein levels and inhibition of cell growth. The growth inhibition was accompanied by changes in cell morphology, cleavage of poly(ADP-ribose) polymerase (PARP) and appearance of apoptotic nuclei. In addition, bcl-2 protein level was reduced and p53 expression increased in growth arrested cells. Interestingly, RI alpha antisense inhibited cell viability and induced apoptosis in the absence of p53, suggesting that these actions of RI alpha antisense are exerted independent of p53. In contrast, two- and four-base mismatched control oligonucleotides had no effect on either cell growth or morphology. These results demonstrate that the RI alpha antisense, which efficiently depletes the growth stimulatory molecule RI alpha, induces cell differentiation and apoptosis, providing a new approach to combat breast cancer cell growth.
Cellular Biochemistry Section, Laboratory of Tumor Immunology and Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-1750, USA.
R K
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Srivastava
A R
AR
Srivastava
P
P
Seth
S
S
Agrawal
Y S
YS
Cho-Chung
D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects / Q000235:genetics; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D054757:Cyclic AMP-Dependent Protein Kinase RIIbeta Subunit; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation / Q000187:drug effects; D006131:Growth Inhibitors / Q000494:pharmacology; D006801:Humans; D009707:Nucleosomes / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
D054757:Cyclic AMP-Dependent Protein Kinase RIIbeta Subunit; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D006131:Growth Inhibitors; D009707:Nucleosomes; D016376:Oligonucleotides, Antisense; C517834:PRKAR1A protein, human; C517837:PRKAR2B protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D011065:Poly(ADP-ribose) Polymerases; D017868:Cyclic AMP-Dependent Protein Kinases