The promyelocytic leukemia zinc-finger gene, PLZF, is frequently downregulated in malignant mesothelioma cells and contributes to cell survival.
DNA copy number analysis was performed, using single-nucleotide polymorphism mapping arrays, to fine map genomic imbalances in human malignant mesothelioma (MM) cell lines derived from primary tumors. Chromosomal losses accounted for the majority of genomic imbalances. All 22 cell lines examined showed homozygous deletions of 9p21.3, centering at the CDKN2A/ARF and CDKN2B loci. Other commonly underrepresented segments included 1p36, 1p22, 3p21-22, 4q13, 4q34, 11q23, 13q12-13, 14q32, 15q15, 18q12, and 22q12, each observed in 55-90% of cell lines. Focal deletions of 11q23 encompassed the transcriptional repressor gene promyelocytic leukemia zinc finger (PLZF), which was validated by analysis of genomic DNA using real-time polymerase chain reaction (PCR). Semi-quantitative RT-PCR and immunoblot analysis revealed that PLZF is greatly downregulated in MM cell lines compared with non-malignant mesothelial cells. Ectopic expression of PLZF in PLZF-deficient MM cells resulted in decreased cell viability, reduced colony formation, as well as increased apoptosis, the latter based on results of various cell death assays and the observation of increased cleavage of caspase 3, PARP, and Mcl-1. These data indicate that deletions of PLZF are a common occurrence in MM and that downregulation of PLZF may contribute to MM pathogenesis by promoting cell survival.
Cheung
M
M
Cancer Genetics and Signaling Program, Fox Chase Cancer Center, Philadelphia, PA 19111-2497, USA.
Pei
J
J
Pei
Y
Y
Jhanwar
S C
SC
Pass
H I
HI
Testa
J R
JR
D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D002872:Chromosome Deletion; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics*; D050762:Cyclin-Dependent Kinase Inhibitor p15 / Q000235:genetics; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics; D015536:Down-Regulation; D018628:Gene Dosage; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000235:genetics* / Q000378:metabolism; D008654:Mesothelioma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D000075722:Promyelocytic Leukemia Zinc Finger Protein; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D025803:Tumor Suppressor Protein p14ARF / Q000235:genetics
C493966:CDKN2B protein, human; D050762:Cyclin-Dependent Kinase Inhibitor p15; D019941:Cyclin-Dependent Kinase Inhibitor p16; D051741:Kruppel-Like Transcription Factors; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D000075722:Promyelocytic Leukemia Zinc Finger Protein; D019253:Proto-Oncogene Proteins c-bcl-2; D025803:Tumor Suppressor Protein p14ARF; C092037:ZBTB16 protein, human; D011065:Poly(ADP-ribose) Polymerases; D053148:Caspase 3