Minichromosome maintenance proteins 2, 3 and 7 in medulloblastoma: overexpression and involvement in regulation of cell migration and invasion.
Minichromosome maintenance (MCM) proteins 2-7 are important in DNA replication licensing. Functional roles beyond licensing are speculated. In addition, significances in medulloblastoma (MB) remain unclear. In this study, we showed the frequent deregulation of MCM2 and MCM3 expression in 7 MB cell lines and 31 clinical samples. Moreover, DAOY and ONS76 and the clinical samples expressed elevated MCM7 transcripts with genomic gain of the gene. Immunopositivity restricted to tumor cells was found in 41, 37 and 53 out of 73 MB cases for MCM2, MCM3 and MCM7, respectively. High-MCM3 expression was associated with poor prognosis. Knockdowns of these MCMs significantly inhibited anchorage-dependent and -independent MB cell growth. The inhibition of MCM3 expression by small interfering RNA knockdown was related to G1 arrest with reduced cyclin A expression, whereas the MCM2- and MCM7-knocked-down cells arrested at G2/M with increased cyclin A expression. Interestingly, we demonstrated the links of these MCMs with cell migration and invasion using wound-healing and Transwell migration/invasion assays. Exogenous overexpression of MCM2, MCM3 and MCM7 increased anchorage-independent cell growth, and also cell migration and invasion capabilities in MB cells. The knockdown reduced the number of filopodial cells and the cells with intense stress fibers by blocking cdc42 and Rho activation. Taken together, deregulation of MCM2, MCM3 and MCM7 expression might be involved in MB tumorigenesis and we revealed undefined roles of these MCMs in control of MB cell migration and invasion.
Lau
K-M
KM
Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong. kmlau@cuhk.edu.hk
Chan
Q K Y
QK
Pang
J C S
JC
Li
K K W
KK
Yeung
W W
WW
Chung
N Y F
NY
Lui
P C
PC
Tam
Y-S
YS
Li
H-M
HM
Zhou
L
L
Wang
Y
Y
Mao
Y
Y
Ng
H-K
HK
D014408:Biomarkers, Tumor / Q000032:analysis; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement / Q000235:genetics*; D002469:Cell Separation; D002528:Cerebellar Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D055028:Comparative Genomic Hybridization; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D053208:Kaplan-Meier Estimate; D008527:Medulloblastoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D064111:Minichromosome Maintenance Complex Component 2; D064126:Minichromosome Maintenance Complex Component 3; D064168:Minichromosome Maintenance Complex Component 7; D009361:Neoplasm Invasiveness / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D011379:Prognosis; D020133:Reverse Transcriptase Polymerase Chain Reaction
D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C066470:MCM3 protein, human; D009687:Nuclear Proteins; C084859:MCM2 protein, human; C101624:MCM7 protein, human; D064111:Minichromosome Maintenance Complex Component 2; D064126:Minichromosome Maintenance Complex Component 3; D064168:Minichromosome Maintenance Complex Component 7