Modulation of prostate carcinoma cell growth and apoptosis by chromogranin A.
OBJECTIVE
We elucidated the effect and possible pathways of chromogranin A in regulating prostatic cancer cell growth.


METHODS
Chromogranin A expression in prostatic cancer cell lines were detected with immunofluorescence flow cytometry (FCM) and the inhibition of cell growth due to chromogranin A antibody was measured using microculture tetrazolium. Cell cycle and RNA changes were evaluated with acridine orange FCM. Intracellular chromogranin A variations were detected with FCM, as were apoptotic changes, p53, Fas and tumor necrosis factor-alpha. Apoptosis and caspase-3 expression of tumor cells was assessed with dual immunohistochemical staining.


RESULTS
Increased chromogranin A expression was observed in PC-3, DU145 and LNCap cells independent of hormone dependence. Dose and time dependent growth inhibition occurred at 12 hours. Chromogranin A antibody arrested PC3 cells in the S-phase immediately after treatment. The number of G0/G1 and G2/M cells subsequently decreased. PC3 tumor cells had transiently increased RNA at 12 hours with a marked decrease at 48 hours. Decreasing chromogranin A expression started at 12 hours and was most prominent at 48 hours. Apoptotic cells markedly increased at 12 hours with an increase in p53, Fas and tumor necrosis factor-alpha (Fas more than the others). Increased apoptotic cell and caspase-3 expression was observed on immunohistochemical stains.


CONCLUSIONS
Chromogranin A is an important neuropeptide regulating the growth of prostate cancer cells. Specific antibodies can suppress its function through apoptotic pathways (Fas and caspase-3), leading to programmed cell death. Chromogranin A antibody mediated apoptosis may be a specific alternative treatment for prostate cancer.
Yu
Dah-Shyong
DS
Uro-Oncology Laboratory, Division of Urology, Department of Surgery, Tri-Service General Hospital, No. 325, Section 2 Cheng-Gung Road, Nei-Hu, Taipei, Taiwan 114, Republic of China.
Hsieh
Dar-Shih
DS
Chang
Sun-Yran
SY
D000906:Antibodies / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics*; D053148:Caspase 3; D020169:Caspases / Q000235:genetics; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D002455:Cell Division / Q000187:drug effects / Q000235:genetics*; D053379:Chromogranin A; D002864:Chromogranins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000276:immunology; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008297:Male; D009376:Neoplasms, Hormone-Dependent / Q000235:genetics / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology; D012334:RNA, Neoplasm / Q000235:genetics; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000473:pathology*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D019014:fas Receptor / Q000235:genetics
D000906:Antibodies; C506150:CHGA protein, human; D053379:Chromogranin A; D002864:Chromogranins; D012334:RNA, Neoplasm; D014409:Tumor Necrosis Factor-alpha; D016159:Tumor Suppressor Protein p53; D019014:fas Receptor; D017430:Prostate-Specific Antigen; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases