Characterization of AMC-HN-9, a cell line established from an undifferentiated carcinoma of the parotid gland: expression of alpha6beta4 with the absence of BP180 and 230.

We recently reported the development of a cell line, AMC-HN-9, established from an undifferentiated carcinoma (UDC) of the parotid gland. AMC-HN-9 consists mostly of spindle-shaped cells, has poor in vitro adhesiveness and an in vitro appearance that is different from that of other epithelial cell lines. To test the hypothesis that structural or functional abnormalities of the hemidesmosomes might contribute to the morphological appearance and biology of UDCs, we studied the expression of hemidesmosomal proteins in AMC-HN-9. Flow cytometry, indirect immunofluorescence, immunoprecipitation, reverse transcriptase-polymerase chain reaction, and cytogenetic analysis were used. AMC-HN-9 cells express the alpha6 and beta4 integrin subunits at nearly the same intensity as head and neck squamous cell carcinoma cell lines. However, AMC-HN-9 does not express BP180 and BP230, although there is no gross deletion of the loci of the BP180 and BP230 genes, suggesting that a more subtle mechanism has silenced these genes. In conclusion, the failure to express certain hemidesmosomal proteins is a likely explanation for the functional and morphologic characteristics of UDC cells both in vivo and in vitro.