Identification of potential therapeutic targets in malignant mesothelioma using cell-cycle gene expression analysis.
Cell-cycle defects are responsible for cancer onset and growth. We studied the expression profile of 60 genes involved in cell cycle in a series of malignant mesotheliomas (MMs), normal pleural tissues, and MM cell cultures using a quantitative polymerase chain reaction-based, low-density array. Nine genes were significantly deregulated in MMs compared with normal controls. Seven genes were overexpressed in MMs, including the following: CDKN2C, cdc6, cyclin H, cyclin B1, CDC2, FoxM1, and Chk1, whereas Ube1L and cyclin D2 were underexpressed. Chk1 is a principal mediator of cell-cycle checkpoints in response to genotoxic stress. We confirmed the overexpression of Chk1 in an independent set of 87 MMs by immunohistochemistry using tissue microarrays. To determine whether Chk1 down-regulation would affect cell-cycle control and cell survival, we transfected either control or Chk1 siRNA into two mesothelioma cell lines and a nontumorigenic (Met5a) cell line. Results showed that Chk1 knockdown increased the apoptotic fraction of MM cells and induced an S phase block in Met5a cells. Furthermore, Chk1 silencing sensitized p53-null MM cells to both an S phase block and apoptosis in the presence of doxorubicin. Our results indicate that cell-cycle gene expression analysis by quantitative polymerase chain reaction can identify potential targets for novel therapies. Chk1 knockdown could provide a novel therapeutic approach to arrest cell-cycle progression in MM cells, thus increasing the rate of cell death.
Romagnoli
Solange
S
Division of Pathology, Department of Medicine, Surgery, and Dentistry, University of Milan Medical School, A.O.S. Paolo, Via A. Di Rudinì 8, 20142 Milano, Italy.
Fasoli
Ester
E
Vaira
Valentina
V
Falleni
Monica
M
Pellegrini
Caterina
C
Catania
Anna
A
Roncalli
Massimo
M
Marchetti
Antonio
A
Santambrogio
Luigi
L
Coggi
Guido
G
Bosari
Silvano
S
D064127:Aurora Kinases; D002453:Cell Cycle / Q000235:genetics*; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D000071877:Checkpoint Kinase 1; D018076:DNA, Complementary / Q000235:genetics; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008654:Mesothelioma / Q000235:genetics* / Q000473:pathology*; D020411:Oligonucleotide Array Sequence Analysis; D010997:Pleural Neoplasms / Q000235:genetics* / Q000473:pathology*; D011494:Protein Kinases / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics / Q000302:isolation & purification; D034741:RNA, Small Interfering / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D018076:DNA, Complementary; D012334:RNA, Neoplasm; D034741:RNA, Small Interfering; D011494:Protein Kinases; D064127:Aurora Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D017346:Protein Serine-Threonine Kinases