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Inhibition of cell proliferation in head and neck squamous cell carcinoma cell lines with antisense cyclin D1
M B Wang1, K R Billings, N Venkatesan
1Division of Head and Neck Surgery, UCLA School of Medicine, West Los Angeles Veterans Administration Medical Center, USA.
Abstract:
Cyclin D1 and cyclin G are essential regulatory factors in the progression of the cell cycle from G0 through G1 and S phase. Aberrations in expression of these cyclins may lead to dysregulated cellular proliferation that could result in neoplasia. Amplification and overexpression of cyclin D1 have been observed in many human cancers, whereas cyclin G is a new cyclin recently described in osteosarcoma cells. This study was performed to determine whether these cyclins were amplified in head and neck squamous cell carcinoma (HNSCC) tumors. Polymerase chain reaction of DNA extracted from 22 HNSCC primary tumors and three HNSCC cell lines did not reveal amplification of cyclin D1 in any of the tumor samples. Southern blot analysis identified amplification of cyclin D1 in a single tumor. Amplification of cyclin G was not observed in any of the tumors by Southern blot hybridization with a cyclin G probe. HNSCC cell lines transfected with antisense cyclin D1 were tested for cell proliferation by the incorporation of 3H-thymidine into cells grown in serum-free media. By 72 hours of incubation, there was a greater than 30% reduction in proliferation of cells transfected with antisense cyclin D1 as compared with non-transfected control cells. The results indicate that cyclin D1 may play an important role in the growth and proliferation of HNSCC cells.
Insights
Cyclin D1 amplification was not found in most head and neck squamous cell carcinoma (HNSCC) tumors, but its inhibition reduced cancer cell proliferation. This suggests cyclin D1 is crucial for HNSCC growth.
Area of Science:
- Oncology
- Molecular Biology
- Cell Cycle Regulation
Background:
- Cyclins regulate cell cycle progression; aberrant expression can cause neoplasia.
- Cyclin D1 is overexpressed in many cancers; cyclin G is newly identified.
- Head and neck squamous cell carcinoma (HNSCC) is a significant malignancy.
Purpose of the Study:
- To investigate cyclin D1 and cyclin G amplification in HNSCC.
- To assess the role of cyclin D1 in HNSCC cell proliferation.
Main Methods:
- DNA extraction from 22 HNSCC tumors and 3 cell lines.
- Polymerase chain reaction (PCR) and Southern blot analysis for gene amplification.
- Antisense cyclin D1 transfection and 3H-thymidine incorporation assay for proliferation.
Main Results:
- No cyclin D1 amplification detected by PCR in HNSCC tumors.
- Southern blot identified cyclin D1 amplification in only one tumor.
- Cyclin G amplification was not observed in any HNSCC tumors.
- Antisense cyclin D1 reduced HNSCC cell proliferation by over 30% within 72 hours.
Conclusions:
- Cyclin D1 amplification is rare in HNSCC.
- Cyclin D1 inhibition significantly reduces HNSCC cell proliferation.
- Cyclin D1 plays a critical role in HNSCC growth and proliferation.