The Expression Of Immunoglobulin Alpha Heavy Chain By Human Epithelial Cancer Cells And Its Biological Function

We previously found a transforming gene Tx from CNE2 genomic DNA library, which has the function of cell malignant transformation. By Tx sequence Blast, we found that in fact Tx is a Ig kappa light chain lacking V region. Using dbEST analyse, we found that some kinds of cancer cell lines can express EST of Ig kappa. So we further confirmed that human cancer cells express Ig kappa mRNA and protein by a series of molecular biology experiments.We found Ig alpha heavy chain in some tumor tissues unexpected. It raised the issue whether human cancer cells could express Ig alpha heavy chain. So we will focus on the expression and function of Ig alpha heavy chain in human epithelial cancer cells. We hope that by studying the Ig alpha chain in cancer cells, people can further understand the significance of Ig expression in cancer cells.1. The prediction of EST of Ig alpha chain in cancers by bioinformation.EST(expressed sequence tag) database is often used to identify in which tissues or cells a given gene can express. By EST search of Ig alpha C region(constant region), we found that the majority of EST come from B lymphocytes, but some ESTs come from lung, stomach, colon, bladder, kidney and cervical cancers. It provides strong proofs of the expression of Ig alpha chain in cancer cells.Furthermore, we analyzed the expression profile of Ig alpha heavy chain in cancer cells, using Virtual Northern Blot. The results showed that Ig alpha chain was expressed in a series of cancer cells including lung, colon, prostate, kidney, ovary and cervical cancers.2. The expression of Ig alpha heavy chain in human cancer cells and tissues.Next, we tried to confirm that human epithelial cancers can express Ig alpha heavy chain. Because of variable V (variable gene), D (diversity gene), J (joining gene) region of Ig, we first analyzed the Ig Ca mRNA. We found Ig Ca mRNA sequences in Hela, MCF-7, SW480, MGC, CNE1 cell lines by RT-PCR and sequencing.Further, we used Northern Blot to determine the mRNA of Ig alpha in Hela, MCF-7, SW480, MGC, CNE1 cell lines. The results showed two transcriptions of Ig...