[Proliferation and differentiation of human salivary gland adenocarcinoma cell line HSG].

The adenocarcinoma cell line derived from an intercalated ductal epithelium of a human salivary gland (HSG) proliferates autonomously mediated by an epidermal growth factor-(EGF)-like molecule with a molecular weight of 46 kDa and an EGF receptor (EGFR). The c-erbB2 protein, a member of EGFR family was also expressed in HSG cells and was involved in the growth signal pathway of HSG cells as well as EGFR. The autocrine growth is regulated by glucocorticoid and retinoic acid (RA) via their receptors. Retinoic acid receptor (RAR) of HSG cells revealed a transcriptional activity in vivo, and the heterodimerization between RAR and 9-cis retinoic acid receptor (RXR) is requisite for the binding with a specific DNA element termed RA response element in vitro. RXR alpha and RXR beta were cloned from HSG cells, and these RXRs, together with RAR, seemed to play a physiological role in RA signaling in vivo.