Multiple cellular mechanisms related to cyclin A1 in prostate cancer invasion and metastasis.
BACKGROUND
Cyclin A1 is a cell cycle regulator that has been implicated in the progression of prostate cancer. Its role in invasion and metastasis of this disease has not been characterized.


METHODS
Immunohistochemistry and cDNA microarray analyses were used to assess protein and mRNA expression of cyclin A1 and proteins with roles in metastasis, including vascular endothelial growth factor (VEGF), metalloproteinase 2 (MMP2), and MMP9, in human prostate cancer. Transient transfection and infection with viral vectors expressing cyclin A1 and short hairpin RNA (shRNA) targeting cyclin A1 were used to study the effects of altered cyclin A1 expression in PC3 prostate cancer cells. The BrdU assay, annexin V staining, and invasion chambers were used to examine cyclin A1 effects on proliferation, apoptosis, and invasion, respectively. The role of cyclin A1 and androgen receptor (AR) in transcription of VEGF and MMP2 was assessed by promoter mutation and chromatin immunoprecipitation. The effect of cyclin A1 expression on tumor growth and metastasis was analyzed in a mouse model of metastasis. All statistical tests were two-sided.


RESULTS
Cyclin A1 protein and mRNA expression were statistically significantly higher in prostate cancers than in adjacent benign tissues. A statistically significant correlation between expression of cyclin A1 and of MMP2, MMP9, and VEGF was observed in prostate tumors from 482 patients (P values from Spearman rank correlation tests < .001). PC3 cells that overexpressed cyclin A1 showed increased invasiveness, and inhibition of cyclin A1 expression via shRNA expression reduced invasiveness of these cells. Eight of 10 mice (80%) bearing PC3 cells overexpressing cyclin A1 had infiltration of tumor cells in lymph node, liver, and lung, but all 10 mice bearing tumors expressing control vector were free of liver and lung metastases and only one mouse from this group had lymph node metastasis (P values from Fisher exact tests < .001). Cyclin A1, in concert with AR, bound to and increased expression from the VEGF and MMP2 promoters.


CONCLUSIONS
Cyclin A1 contributes to prostate cancer invasion by modulating the expression of MMPs and VEGF and by interacting with AR.
Wegiel
Barbara
B
Division of Pathology, Department of Laboratory Medicine, Lund University, University Hospital, Malmö, Sweden.
Bjartell
Anders
A
Tuomela
Johanna
J
Dizeyi
Nishtman
N
Tinzl
Martina
M
Helczynski
Leszek
L
Nilsson
Elise
E
Otterbein
Leo E
LE
Härkönen
Pirkko
P
Persson
Jenny Liao
JL
D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D019925:Cyclin A / Q000235:genetics / Q000378:metabolism*; D056750:Cyclin A1; D004797:Enzyme-Linked Immunosorbent Assay; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D015741:Metribolone / Q000494:pharmacology; D051379:Mice; D009361:Neoplasm Invasiveness; D009389:Neovascularization, Pathologic / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D011471:Prostatic Neoplasms / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology*; D012333:RNA, Messenger / Q000378:metabolism; D011944:Receptors, Androgen / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D014408:Biomarkers, Tumor; C503745:CCNA1 protein, human; D019925:Cyclin A; D056750:Cyclin A1; D012333:RNA, Messenger; D011944:Receptors, Androgen; D042461:Vascular Endothelial Growth Factor A; D015741:Metribolone; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9