Over-expression of mutant EGFR protein frequently occurred in the lung cancer tissues of mutant EGFR-transgenic mice and also associated with CD82 down-regulation.
These results reemphasize the important role of MRP-1/CD9 and KAI1/CD82 in the suppression of the metastatic process and also show the feasibility of gene therapy when using these tetraspanins for lung cancer to prevent metastasis to the regional lymph nodes.
Although ectopic expression of CD82 in nonsmall cell lung carcinoma cells did not affect the tyrosine phosphorylation of c-Met, these cells showed significant suppression of HGF-induced lamellipodial protrusion and cell migration.
The H1299 human lung carcinoma cells were transfected with pcDNA3.1-CD82 and stable transfectant clones that had a high KAI1/CD82 expression were obtained.
These observations indicate that NF-kappaB activation may play a role in the regulation of KAI1/CD82 expression in lung cancer cells independently of wild-type p53, and suggest that KAI1/CD82 expression may be regulated by interaction with the host microenvironment.
In the present study, our aim was to ascertain the relationship between down-regulation of KAI1 mRNA expression and KAI1 gene alterations in lung cancer.
It is conceivable that the evaluation for MRP-1 and KAI1 expression may identify node-negative lung cancer patients who are at high risk for early disease recurrence, and thus need intensive adjuvant therapy.
This set of observations suggests that assessment of the expression status of KAI1/CD82 and MRP-1/CD9 by tumors may provide prognostic information on the clinical behavior of lung cancer.