Related Experiment Videos
PRK, a cell cycle gene localized to 8p21, is downregulated in head and neck cancer
1Division of Hematology/Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA. wei.dai@uc.edu
Abstract:
The human PRK gene encodes a protein serine/threonine kinase of the polo family and plays an essential role in regulating meiosis and mitosis. We have previously shown that PRK expression is downregulated in a significant fraction of lung carcinomas. Our current studies reveal that PRK mRNA expression is downregulated in a majority (26 out of 35 patients) of primary head and neck squamous-cell carcinomas (HNSCC) compared with adjacent uninvolved tissues from the same patients, regardless of stage. In addition, PRK transcripts were undetectable in one of the two HNSCC cell lines analyzed. Ectopic expression of PRK, but not a PRK deletion construct, in transformed A549 fibroblast cells suppresses their proliferation. Furthermore, fluorescence in situ hybridization analyses show that the PRK gene localizes to chromosome band 8p21, a region that exhibits a high frequency of loss of heterozygosity in a variety of human cancers, including head and neck cancers, and that is proposed to contain two putative tumor suppressor genes. Considering that PRK plays an important role in the regulation of the G2/M transition and cell cycle progression, our current studies suggest that deregulated expression of PRK may contribute to tumor development. Genes Chromosomes Cancer 27:332-336, 2000.
Insights
The PRK gene, crucial for cell division, is downregulated in most head and neck cancers. This suggests PRK may act as a tumor suppressor, potentially contributing to cancer development.
Area of Science:
- Molecular Biology
- Cancer Genetics
- Cell Cycle Regulation
Background:
- The PRK gene encodes a polo-like kinase involved in meiosis and mitosis.
- Previous studies indicated PRK downregulation in lung carcinomas.
- PRK's role in cell cycle progression and its potential as a tumor suppressor are under investigation.
Purpose of the Study:
- To investigate PRK mRNA expression levels in head and neck squamous-cell carcinomas (HNSCC).
- To determine the functional significance of PRK in cancer cell proliferation.
- To map the chromosomal location of the PRK gene and assess its association with cancer-related chromosomal abnormalities.
Main Methods:
- Quantitative analysis of PRK mRNA expression in HNSCC tissues and cell lines.
- Functional assays involving ectopic PRK expression in cancer cells.
- Fluorescence in situ hybridization (FISH) for gene localization.
Main Results:
- PRK mRNA expression was downregulated in a majority (26/35) of primary HNSCC samples compared to adjacent normal tissues.
- PRK transcripts were undetectable in one of two analyzed HNSCC cell lines.
- Ectopic PRK expression suppressed proliferation in transformed A549 fibroblast cells.
- FISH analysis localized the PRK gene to chromosome band 8p21, a region frequently altered in cancers.
Conclusions:
- PRK downregulation is a common event in HNSCC.
- PRK may function as a tumor suppressor gene involved in cell cycle regulation.
- Altered PRK expression could contribute to the development of head and neck cancers.