Limited expression of reticulocalbin-1 in lymphatic endothelial cells in lung tumor but not in normal lung

Lymphatic endothelial cells in tumors (T-LECs) are considered to have different characteristics from LECs in non-tumor tissues (N-LECs). However, differences between the two types have not been well analyzed at molecular level. In this report, we performed differential proteome analysis of T-LEC and N-LEC models prepared by cultivation of LECs in tumor conditioned medium. By expression profiling of identified proteins using tissue microarrays, reticulocalbin-1 was found to be expressed in clinical specimen-derived T-LECs and lung cancer cells but not N-LECs. It is suggested that reticulocalbin-1 may be an important molecule in understanding T-LEC function and control of lymphatic metastasis.

Research highlights
► We modeled lymphatic endothelial cells in tumors (T-LECs) and in non-tumor (N-LECs) in vitro.
► Protein expression between them was compared by proteome analysis.
► Reticulocalbin-1 was found to be expressed on T-LECs in clinical specimens but not N-LECs.
► It may be a key molecule in understanding T-LEC function and lymphatic metastasis.