Characteristics of expression of the genes of EGR1, neurotrophins, and their receptors in normal human lung tissues and lung cancers

Abstract

The expression of genes of a number of neurotrophins, their receptors, and also EGR1—one of the participants in the neurotrophin signal pathways—was investigated in normal human lung tissues, as well as in tumor samples from squamous cell carcinoma and adenocarcinoma. Differential expression of the expression of neurotrophin genes (NGF, BDNF, and NT3) was revealed in normal human lung tissues by PCR with reverse transcription. It was shown that the level of expression of the RNA of the NGF gene impaired samples of tumor/adjacent tissue varies from very low to substantial. In half the cases, the expression of the RNA of this gene in the tumor does not differ from that in the adjacent tissue, whereas in half the cases differential expression is observed. An analysis of the expression of mRNA of the BDNF and NT3 genes revealed an equally low level of transcripts in most of the tumor samples and the normal tissues adjacent to them. The RNA of neurotrophin receptor genes TrkA, TrkB, and p75 is not expressed in normal lung tissues and lung cancer samples or is at a very low level. Differential expression of the TrkC gene was detected both in the control samples, obtained from healthy lungs, and in a number of paired tumor/adjacent tissue samples. In normal lung tissues a high level of EGR1 transcripts is determined. In most of the paired tumor/adjacent tumor samples, there is no expression of the RNA of this gene, or it is sharply reduced in the tumor in comparison with the noncancerous tissue adjacent to it.