Protein kinase A RIalpha antisense inhibition of PC3M prostate cancer cell growth: Bcl-2 hyperphosphorylation, Bax up-regulation, and Bad-hypophosphorylation.
It has been shown that expression of the RIalpha subunit of cyclic AMP (cAMP)-dependent protein kinase is enhanced in human cancer cell lines, primary tumors, and cells after transformation. Using an antisense strategy, we have shown that RIalpha has a role in neoplastic cell growth in vitro and in vivo. In the present study, we have investigated the sequence- and target-specific effects of exogenous RIalpha antisense oligodeoxynucleotides (ODNs) and endogenous antisense gene on tumor growth, apoptosis, and cAMP signaling in androgen-insensitive prostate cancer cells, both in vitro and in nude mice. Here, we show that an RIalpha antisense, RNA/DNA mixed backbone ODN exerts a reduction in RIalpha expression at both the mRNA and protein levels, up-regulation of both the RIIbeta subunit of cAMP-dependent protein kinase or protein kinase A and c-AMP-phosphodiesterase IV expression, and inhibition of cell growth. Growth inhibition was accompanied by changes in cell morphology and the appearance of apoptotic nuclei. In addition, Bcl-2 hyperphosphorylation; increase in the proapoptotic proteins Bax, Bak, and Bad; and Bad hypophosphorylation occurred in the antisense-treated cells. These effects of exogenously supplied antisense ODN mirrored those induced by endogenous antisense gene overexpression. The RIalpha antisense ODNs, which differed in sequence or chemical modification, promoted a sequence- and target-specific reduction in RIalpha protein levels and inhibited tumor growth in nude mice. These results demonstrate that in a sequence-specific manner, RIalpha antisense, via efficient depletion of the growth stimulatory molecule RIalpha, induces growth inhibition, apoptosis, and phenotypic (cell morphology) changes, providing an innovative approach to combat hormone-insensitive prostate cancer cell growth.
Cho
Yee Sook
YS
Cellular Biochemistry Section, Basic Research Laboratory, Center for Cancer Research, National Cancer Institute/NIH, Bethesda, MD 20892-1750, USA.
Kim
Meyoung-Kon
MK
Tan
Langzhu
L
Srivastava
Rakesh
R
Agrawal
Sudhir
S
Cho-Chung
Yoon S
YS
D017209:Apoptosis; D015152:Blotting, Northern; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism* / Q000494:pharmacology; D015536:Down-Regulation; D006801:Humans; D008297:Male; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D010766:Phosphorylation; D011471:Prostatic Neoplasms / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors; D014407:Tumor Cells, Cultured; D015854:Up-Regulation; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein
C494819:BAD protein, human; C494826:BAX protein, human; D002352:Carrier Proteins; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D016376:Oligonucleotides, Antisense; C517834:PRKAR1A protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases