In this study, we analyzed the expression profile of four genes (CCNA2, CCNB1, CCNB2, and CDK1)
in laryngeal squamous cell carcinoma (LSCC) cell lines and tumor
samples. With the application of microarray platform, we have shown the
overexpression of these genes in all analyzed LSCC samples in comparison
to non-cancer controls from head and neck region. We have selected CDK1
for further analysis, due to its leading role in cell cycle regulation.
It is a member of the Ser/Thr protein kinase family of proven oncogenic
properties. The results obtained for CDK1
were further confirmed with the application of reverse transcription
quantitative polymerase chain reaction (RT-qPCR) technique, Western
blot, and immunohistochemistry (IHC). The observed upregulation of CDK1
in laryngeal squamous cell carcinoma has encouraged us to analyze for
genetic mechanisms that can be responsible this phenomenon. Therefore,
with the application of array-CGH, sequencing analysis and two methods
for epigenetic regulation analysis (DNA methylation and miRNA
expression), we tried to identify such potential mechanisms. Our
attempts to identify the molecular mechanisms responsible for observed
changes failed as we did not observe significant alterations neither in
the DNA sequence nor in the gene copy number that could underline CDK1
upregulation. Similarly, the pyrosequencing and miRNA expression
analyses did not reveal any differences in methylation level and miRNA
expression, respectively; thus, these mechanisms probably do not
contribute to elevation of CDK1 expression in LSCC. However, our results suggest that alteration of CDK1 expression on both mRNA and protein level probably appears on the very early step of carcinogenesis.