p21CIP1 Induces Apoptosis via Binding to BCL2 in LNCaP Prostate Cancer Cells Treated with MCS-C3, A Novel Carbocyclic Analog of Pyrrolopyrimidine.
BACKGROUND
Previously, we synthesized a new carbocyclic analog of pyrrolo[2,3-d]pyrimidine nucleoside, designated MCS-C3. Recently, we found that LNCaP androgen-responsive prostate cancer cells treated with MCS-C3 rapidly undergo intrinsic apoptosis through dramatic up-regulation of p21(CIP1). The present study aimed to evaluate the cellular functions and underlying molecular mechanisms of p21(CIP1) on apoptotic induction in LNCaP cells treated with 6 μM MCS-C3.


MATERIALS AND METHODS
Western blots, flow cytometric assay, immunoprecipitation, and transmission electron microscopy analysis were used to measure apoptotic induction in 6-μM MCS-C3-treated LNCaP cells. Effects of MCS-C3 on gene expression of p21(CIP1) were measured by semi-quantitative real-time polymerase chain reaction, and small interfering RNA transfection.


RESULTS
MCS-C3 induced appreciable caspase-dependent apoptosis associated with the significant up-regulation of p53-dependent p21(CIP1) in LNCaP cells. Moreover, this apoptotic induction was caused by direct binding of p21(CIP1) to anti-apoptotic B-cell lymphoma 2 (BCL2) protein, and antagonizing BCL2 function. In addition, MCS-C3-mediated apoptotic induction, and up-regulation of p21(CIP1) were almost completely blocked by the treatment of androgen-responsive LNCaP cells with flutamide, an androgen receptor (AR) antagonist.


CONCLUSION
We identified that induction of intrinsic apoptosis in LNCaP cells by 6 μM MCS-C3 is associated not only with p53 activation but also with mediation of AR. In the present study, we identified the cellular functions and underlying molecular mechanisms of p53-dependent and AR-associated p21(CIP1) on apoptotic induction via direct binding to BCL2 in LNCaP cells treated with 6 μM MCS-C3.
['Choi|Ko-Woon|KW|', 'Suh|Hyewon|H|', 'Oh|Ha Lim|HL|', 'Ryou|Chongsuk|C|', 'Lee|Chul-Hoon|CH|']
D017209:Apoptosis D045744:Cell Line, Tumor D049109:Cell Proliferation D006801:Humans D008297:Male D011471:Prostatic Neoplasms D019253:Proto-Oncogene Proteins c-bcl-2 D011743:Pyrimidines D011758:Pyrroles D015398:Signal Transduction D014162:Transfection
p21CIP1 apoptosis BCL2 Prostate cancer LNCaP cells