Characterization of centriole duplication in human epidermis, Bowen's disease, and squamous cell carcinoma.

BACKGROUND

Centrosomes contain two centrioles: a pre-existing mature centriole and a newly formed immature centriole. Each centriole is duplicated once within a cell cycle, which is crucial for proper centrosome duplication and cell division.

OBJECTIVE

To describe the centrosome duplication cycle in human epidermis, Bowen's disease (BD), and squamous cell carcinoma (SCC).

METHODS

Immunofluorescent staining of centriolar proteins and Ki-67 was used to evaluate cell cycles and the number of centrioles. Centrobin and Outer dense fiber of sperm tails 2 (ODF2) were used as markers for immature and mature centrioles, respectively.

RESULTS

Normal human primary epidermal keratinocytes in a monolayered culture have one centrobin centriole (CTRB cells) supposed in G0/G1 phases or have two centrobin centrioles (CTRB cells) supposed in S-G2 phase. In a three-dimensional culture and in vivo human epidermis, the majority of suprabasal cells were CTRB cells, in spite of their non-proliferative Ki-67 nature. The tumor mass of BD and SCC contained CTRB cells and Ki-67 proliferating and Ki-67 non-proliferative CTRB cells. Clumping cells in BD had increased numbers of centrioles, with an approximate 1:1 to 2:1 ratio of centrobin to ODF2 centrioles.

CONCLUSIONS

The cell cycle arrest of suprabasal cells is distinct from the G0 arrest of monolayered epithelial cells. Tumor mass of BD and SCC contained non-proliferative cells with the characteristics of the suprabasal cells of normal epidermis. A constant ratio of the number of centrobin to ODF2 centrioles indicates that multiple centrioles were induced by cell division failure rather than centriole overduplication in clumping cells.