Expression of SNC73, a transcript of the immunoglobulin α-1 gene, in human epithelial carcinomas

AIM： To investigate the expression of SNC73, a transcript of the immunoglobulin α-1 gene （IgA1-H chain）, in human epitheliα-derived tumor cells. METHODS： Total RNAs and cell lysates were prepared from five different human epithelial cell lines derived from lung, stomach, liver, skin, and breast, respectively. RT-PCR and immunoblot analysis of these five cell lines were done. Both RT-PCR and immunochemistry were used to detect the expression of SNC73 in these cell lines. We also examined the expression of SNC73 in normal epithelial cells of colon mucosa by in situ hybridization. RT-PCR and immunoblot analysis were used to determine whether the recombination activating gene1/2 （RAG1 and RAG2） is present. The expression of three immunoglobulin transcription factors, EBF, E2A and Pax5, and the heavy chain of IgA1 and two types of light chains of immunoglobulin （κ and λ） in the aforementioned cell lines were analyzed by RT-PCR and immunochemistry, respectively. All the RT-PCR products were analyzed by sequencing. RESULTS： The results of RT-PCR and immunochemistry showed that both mRNA and protein of SNC73 were expressed in five human epitheliα-derived cancer cell lines. These data were further confirmed in the normal epithelial cells of colon mucosa by in situ hybridization. Also, the heavy chain of IgA1 and κ light chain were detected in these cells, but no λ light chain was observed. Both RAG1 and RAG2 were expressed in these human epitheliα-derived cancer cell lines and the sequence was identical to that expressed in pre-B and pre-T cells. In addition to RAG1 and RAG2, the mRNA in one of the immunoglobulin transcription factors, EBF, was also detected in these cell lines, and Pax5 was only expressed in SW480 cells, but no expression of E2A was observed in all the five cell lines. CONCLUSION： Immunoglobulin A1 is originally expressed and V（D）J recombination machine is also present in non-lymphoid cells, suggesting that V（D）J recombination machine mediates the assembly of immunoglobulin A1 in non-lymphoid cells as in prelymphocytes.

An Experimental Study on the Flexibility of Prevention against Thrombosis Following Mechanical Valve Replacement by tPA Gene Transduction

Objectives Use a gene suture immersed recombinant tissue-type plasminogen activator （r-tPA）expression plasmid to transduce myocardia to prevent the thrombosis after mechanical tricuspid valve replacement in pigs. Methods A r-tPA gene plasmid was constructed and conjugated to a novel cationic phosphonolipid and a r-tPA gene suture was made. Eighteen pigs were selected and divided into two groups at randomization. There were 9 pigs in the experimental group and 9 in the control group, all the 18 pigs＇ tricuspids were replaced with mechanical valves. The gene threads were sutured into the right ventricular walls near mechanical valves and an ultrasound was used on the surfaces of the right ventricular walls for the gene transfer in the experimental group. Coagulative function, D-dimer level of the blood and the thrombosis on the surfaces of the valves were observed. Results r-tPA gene plasmid was successfully constructed and r-tPA protein was expressed in the ventricular cells around the gene sutures. D-dimer reached its peak level （ 1.67 ±0. 79） μg · mL^-1 in 1 week after operation in two groups, but it decreased to preoperation level thereafter in control group and kept on the high level and reincreased to a new high level （ 1.89 ± 0.79 ） μg · mL^-1 until the end of the experiment in experimental group. The thromboses around the valves were found in all the control group （100%） but only 1 （ 11.11% ） case in experimental group. There were no changes in prothrombin time pre and post operation in two groups. Conclusions Using gene suture immersed r-tPA expression plasmid to transduce myocardia might be a best substitution for life long anti-coagulation therapy for the patients, who underwent operation.