Seven novel and stable translocations associated with oncogenic gene expression in malignant melanoma.
Cytogenetics has not only precipitated the discovery of several oncogenes, but has also led to the molecular classification of numerous malignancies. The correct identification of aberrations in many tumors has, however, been hindered by extensive tumor complexity and the limitations of molecular cytogenetic techniques. In this study, we have investigated five malignant melanoma (MM) cell lines from at least three different passages using high-resolution R-banding and the recently developed methods of comparative genomic hybridization and multicolor or multiplex fluorescence in situ hybridization. We subsequently detected nine consistent translocations, seven of which were novel: dic(1;11)(p10;q14), der(9)t(3;9)(p12;p11), der(4)t(9;4;7)(q33:p15-q23:q21), der(14)t(5;14)(q12;q32), der(9)t(9;22)(p21;q11), der(19)t(19;20)(p13.3;p11), der(10)t(2;12;7;10)(q31:p12-->pter:q11.2-->q31:q21), der(19)t(10;19)(q23;q13), and der(20)t(Y;20)(q11.23;q13.3). Furthermore, using the human HG-U133A GeneChip, positive expression levels of oncogenes or tumor-related genes located at the regions of chromosomal breakpoints were identified, including AKT1, BMI1, CDK6, CTNNB1, E2F1, GPNMB, GPRK7, KBRAS2, LDB2, LIMK1, MAPK1, MEL, MP1, MUC18, NRCAM, PBX3, RAB22A, RAB38, SNK, and STK4, indicating an association between chromosomal breakpoints and altered gene expression. Moreover, we also show that growth of all five cell lines can be significantly reduced by downregulating CDK6 gene expression with small interfering RNA (siRNA). Because the majority of these breakpoints have been reported previously in MM, our results support the idea of common mechanisms in this disease.
Okamoto
Ichiro
I
Division of General Dermatology, Department of Dermatology, Center of Excellence and the Ludwig Boltzmann Institut for Clinical and Experimental Oncology, Medical University of Vienna, Vienna A-1090, Austria. ichiro.okamoto@meduniwien.ac.at
Pirker
Christine
C
Bilban
Martin
M
Berger
Walter
W
Losert
Doris
D
Marosi
Christine
C
Haas
Oskar A
OA
Wolff
Klaus
K
Pehamberger
Hubert
H
D002460:Cell Line; D045744:Cell Line, Tumor; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D019457:Chromosome Breakage; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases / Q000235:genetics* / Q000378:metabolism; D003582:Cytogenetics; D015536:Down-Regulation; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008545:Melanoma / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D034741:RNA, Small Interfering / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013696:Temperature; D014178:Translocation, Genetic
D034741:RNA, Small Interfering; C495911:CDK6 protein, human; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases