Expression of CD44 Isoforms in Human Colorectal Cancer Cell Lines

The expression profile of CD44 isoforms in 55 colorectal cancer (CRC) cell lines has been evaluated based on mRNA sequencing data from the Cancer Cell Line Encyclopedia database. The distribution of CD44 mRNA isoforms differs significantly between CRC lines. In 13 studied lines, including Caco-2 and RKO, CD44 expression was not detected. In most other lines, isoform 3 of CD44 mRNA was the most abundant; however, the level of its expression varied and it was absent in the MDST8 and SNU503 lines. The highest level of isoform 3 was observed in CW2 and T84 lines. The next most frequent was isoform 4 with its expression level being lower than that of isoform 3, except for the HCT116, SNU81, NCIH508 and SNUC4 lines. The highest expression of isoform 4 was detected in the MDST8 line, the only line in which isoform 6 was also expressed. Isoform 2 was also present in CRC cell lines; its highest expression level was found in the SNU503 line. Isoforms 1, 5, and 7 were not expressed in any of the studied lines. It is necessary to take into account the mRNA expression profile of specific CD44 isoforms when choosing a cell model to study its role in CRC.