Significance Of Alcam In Endometrial Malignant Transformation

PART I Expression of ALCAM in normal, hyperplastic and malignant endometrial tissueObjective:Endometrial cancer is one of the most common malignancies of the female genital tract. Endometrial cancer includes two different clinico-pathological and biological variants including estrogen-dependent (type-1) and estrogen-independent (type-2) endometrial cancer. Type-1 (endometrioid adenocarcinoma, EC) accounts for about 80% of endometrial tumors. The widely accepted pathway in the development of EC is the transition from atypical endometrial hyperplasia to invasive adenocarcinoma, which has a background of unopposed estrogen stimulation. However, other pathways that may play important roles in progression of EC remain to be elucidated. Activated leukocyte cell adhesion molecule (ALCAM/CD166) is a member of the IgSF. ALCAM is involved in both heterophilic (ALCAM-CD6) and homophilic (ALCAM-ALCAM) cell-cell interactions. As a CAM, ALCAM plays a physiological role in many kinds of tissues as well as in malignancies. The aim of the present study was to investigate the potential role of ALCAM in the transition from normal endometrium to EC and analyze the association of ALCAM expression with EC clinicopathologic parameters.Methods:To clarify the role of ALCAM in endometrial tumorigenesis, we determined the levels of protein and messenger RNA expression of ALCAM in human endometrial tissue (proliferative phase [n=20], secretory phase [n=20], simple hyperplasia [n=15], complex hyperplasia [n=12], atypical hyperplasia [AH, n=14], EC [n=42]) using immunohistochemistry, Western blot, and semiquantitative reverse transcription polymerase chain reaction, respectively.Results:Expression of ALCAM detected by immunohistochemistry showed a gradual increase from normal endometrium to atypical hyperplasia in a membranous pattern; in addition, cytoplasmic staining emerged in a few cases of simple hyperplasia and complex hyperplasia, which also showed an increasing tendency. Most cases of EC showed a homogenously strong staining in all parts of the tumor; other cases showed either membranous or cytoplasmic strong staining; heterogeneous loss of membranous staining was also found in some cases. Similar results of ALCAM expression were detected by reverse transcription polymerase chain reaction and Western blot. In EC, ALCAM expression was significantly increased in high-grade tumors and cases with myometrial invasion; however, no correlation was found between ALCAM expression and surgical pathological stages.Conclusions:The expression of ALCAM was significantly increased in the groups of AH and EC compared with those in the groups of SH, CH, PE, and SE, suggesting that ALCAM is involved in the process of endometrial carcinogenesis. ALCAM expression was significantly increased in cases with myometrial invasion than no invasive cases suggest that ALCAM may be associated with progression of endometrial cancer. PART?Regulation of ALCAM expression in endometrial adenocarcinoma cell lines by megestrol acetateObjective:To determine the expression change of ALCAM in endometrial adenocarcinoma cell lines (Ishikawa cell and KLE cell) in response to progesterone, and to evaluate the role of ALCAM in the anti-cancer effects of progesterone.Methods:MTT assay was used to determine the inhibitory concentration 50% (IC50) of megestrol acetate (MA) in treating endometrial adenocarcinoma cell lines. After the cell was treated with MA at IC50, the localization of ALCAM was examined by immunocytochemical staining, and the protein and mRNA expression levels of ALCAM were further quantified by western blot and Reverse Transcription PCR respectively. The abilities of migration of endometrial adenocarcinoma cells were assessed using wound healing assay after administration of MA.Results:The inhibitory effect of MA on the growth of Ishikawa cell was dose and time dependent. The IC50 of MA on Ishikawa was 20 mg/l after incubated for 48 hours, and the expression of ALCAM was significantly decreased at both protein and mRNA levels compared with control group. MA can decrease the ability of migration of Ishikawa cells. No significant difference for expression of ALCAM at both protein and mRNA levels of KLE cell was found after MA use. No effect of MA on the abilities of migration of KLE cells was found.Conclusion:MA can inhibit the growth and migration of Ishikawa cell which may be related with down-regulated effects of MA on the expression of ALCAM. Progestin resistance in treatment of endometrial cancer may be related with the expression level of ALCAM.