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.