Biological Assay for Activity and Molecular Mechanism of Retinoids in Cervical Tumor Cells

Doris M. Benbrook, Shennan Lu, Cole Flanagan, Jane Shen-Gunther, Lee H. Angros, Stan A. Lightfoot
1997 Gynecologic Oncology  
but in the United States, Canada, and Western Europe early The composition and response of the retinoid signaling pathway detection of precursor lesions with Papincolaou (PAP) smear in a human cell line (CC-1), representative of a low grade cervical screening programs has greatly decreased the mortality of carcinoma, were evaluated. Reverse-transcriptase polymerase this disease [8]. The human papillomavirus (HPV) has been chain reaction (RT-PCR) analysis demonstrated expression of cyidentified
more » ... n the vast majority of cervical tumors and is betoplasmic retinol binding protein, CRBPI, cytoplasmic retinoic lieved to be an etiologic agent in the development of this acid binding protein, CRABPII, and nuclear retinoic acid recepdisease. HPV types 16, 18, 31, and 33 are most frequently tors, RARa, RARg, RXRa, and RXRb, but not CRABPI or found in advanced cancer and are considered to be of the RARb. This pattern is similar to that of the ectocervix. Activation high risk type [9]. of endogenous nuclear receptors was evaluated in a reporter sub-Transfection of type 16 or 18 HPV DNA into normal line of CC-1, called CC-B, containing a reporter gene controlled by epithelial cells induces immortalization (unlimited growth a retinoic acid responsive element (RARE) and thymidine kinase promoter. Retinoid treatment of CC-B resulted in dose-dependent potential) and increased epidermal growth factor receptor increases in reporter gene expression. Retinoids inhibited growth (EGF-R) expression [10-12]. In normal epithelium, EGFat concentrations greater than 100 nM. 9-cis retinoic acid (1 nM) R is expressed in the proliferating basal cells and is decreased significantly stimulated growth. Immunohistochemical analysis of or not expressed with increasing differentiation of cells to-CC-B organotypic cultures demonstrated a high level of epidermal ward the mucosal surface [13, 14]. An increase in the number growth factor receptor (EGF-R) expression that was decreased by of cells expressing EGF-R is observed in squamous intraepiretinoids. The degree of RARE transactivation induced by retithelial lesions (SIL) of the cervix [13, 14]. The higher grade noids significantly correlated with the degree of inhibition of of SILs exhibit a greater percentage of proliferating cells growth (R Å 0 0.96) and EGF-R expression (R Å 0 0.92). The doseand a corresponding increase in the numbers of EGF-Rdependent and retinoid-specific responses of CC-1 at the molecular expressing cells. This results in a positive correlation beand biological levels demonstrate the utility of this reporter cell line for evaluation of retinoid activities. ᭧ 1997 Academic Press tween grade of tumor and EGF-R expression. In invasive squamous cervical carcinoma, overexpression of EGF-R has been associated with biological aggressiveness of the tumor
doi:10.1006/gyno.1997.4736 pmid:9234931 fatcat:25pm24azizfvde4tmofmfzpnie