Carcinoembryonic antigen in osteosarcoma

CEACAM6 is associated with osteosarcoma metastasis and facilitates epithelial-mesenchymal transition in osteosarcoma cells

Background

Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) is a member of CEACAM family and has been reported to be upregulated in various types of human cancer and involved in tumor progression and metastasis. However, the biological roles and clinical significances of CEACAM6 in osteosarcoma still remain to be elucidated.

Materials and methods

Real-timePCR, immunohistochemistry and Western blot analysis were used to determine CEACAM6 expression in osteosarcoma cell lines and clinical specimens. Then the clinical relevance of CEACAM6 was analyzed in osteosarcoma. The function of CEACAM6 in osteosarcoma was examined by wound-healing and cell invasion assays, and expression levels of epithelial-mesenchymal transition markers.

Results

In the present study, we found that CEACAM6 was markedly upregulated in metastatic osteosarcoma tissues when compared with the nonmetastatic osteosarcoma tissues. Upregulation of CEACAM6 was significantly associated with lung metastasis status (P=0.006) in patients with osteosarcoma. Survival analyses suggested that osteosarcoma patients with high CEACAM6 expression had a significantly shorter overall survival time and lung metastasis-free survival time than those with low CEACAM6 expression. Knockdown of CEACAM6 inhibits osteosarcoma cell migration and invasion. Moreover, silencing CEACAM6 suppressed osteosarcoma cells epithelial-mesenchymal transition.

Conclusion

Taken together, this study suggests that CEACAM6 might be a promising biomarker and a potential therapeutic target for the treatment of metastatic osteosarcoma.

Immunoperoxidase staining for carcinoembryonic antigen in colonic carcinoma, osteosarcoma, and chordoma

An indirect immunoperoxidase method was used in an attempt to detect carcinoembryonic antigen (CEA) in 17 well-differentiated colonic adenocarcinomas, five osteosarcomas, and four chordomas. Fifteen of the adenocarcinomas were positive, and five of them had been fixed and embedded in 1952 and one in 1942. Two other adenocarcinomas from 1942 were not positive. CEA was not demonstrated in any of the osteosarcomas or chordomas.

Presence of a carcinoma-associated antigen(s) in the spent chemically defined medium of a human colon carcinoma cell line

The human colon carcinoma cell line HT-29 was adapted to grow in chemically defined medium (CDM). The spent CDM (S-CDM) was concentrated by Amicon filtration and the crude HT-29 S-CDM purified by 40% saturated (NH4)2 SO4 precipitation. The purified antigen was tested by a microcomplement fixation (MCF) assay against the sera of cancer patients of various histologic types and against the sera of normal donors. Fifteen of 20 (75%) colon cancer, 16/20 (80%) breast cancer sera, 14/19 (74%) lung cancer sera, and 13/20 (65%) miscellaneous carcinoma sera were positive in the MCF. By contrast, 2/21 (10%) melanoma sera, 7/20 (35%) sarcoma sera, and 2/19 (11%) normal sera were positive. These data suggest the presence of a carcinoma-associated antigen in the spent CDM of the HT-29 colon carcinoma cell line adapted to grow in CDM.