Abstract
A humoral immune response against aberrant tumor proteins can be elicited in cancer patients, resulting in the production of auto-antibodies (Abs). By serological proteome analysis we identified the surface membrane protein ADAM10, a metalloproteinase that has a role in epithelial-tumor progression and invasion, as a target of the immune response in colorectal cancer (Crc). A screening carried out on the purified protein using testing cohorts of sera (Crc patients n = 57; control subjects n = 39) and validation cohorts of sera (Crc patients n = 49; control subjects n = 52) indicated that anti-ADAM10 auto-Abs were significantly induced in a large group (74%) of colon cancer patients, in particular in patients at stage II and III of the disease. Interestingly, in Crc patients classified as stage III disease, the presence of anti-ADAM10 auto-Abs in the sera was associated with a favourable follow-up with a significant shifting of the recurrence-free survival median time from 23 to 55 months. Even though the ADAM10 protein was expressed in Crc regardless the presence of auto-Abs, the immature/non-functional isoform of ADAM10 was highly expressed in the tumor of anti-ADAM10-positive patients and was the isoform targeted by the auto-Abs. In conclusion, the presence of anti-ADAM10 auto-Abs seems to reflect the increased tumor expression of the immunogenic immature-ADAM10 in a group of Crc patients, and is associated with a favourable prognosis in patients at stage III of the disease.
Highlights
In cancer, the host’s immune system acts to eliminate cells expressing qualitatively and/or quantitatively aberrant proteins that can be recognised by both T and B cells
An enrichment in the biotinylated surface proteins was found in the fraction of protein extracted from LS180 cells bound to the avidin-affinity-column as inferred by hybridization with HRP-streptavidin on two-dimensional electrophoresis (2DE)-resolved protein (Supplemental Materials SM-Figure 1A), and as confirmed by western blot (WB) reactivity for membrane proteins (SM-Figure 1B)
In order to determine whether sera from colorectal cancer (Crc) patients identified in the previous study as immunoreactive for intracellular antigens [15] might contain auto-Abs specific for membrane antigens, we used as a discovery tool a pool of six of these sera to test the reactivity on the 2DE-membrane tumor proteome
Summary
The host’s immune system acts to eliminate cells expressing qualitatively and/or quantitatively aberrant proteins that can be recognised by both T and B cells. We applied the SERPA approach to characterize the humoral immune response in Crc patients identifying immunogenic proteins expressed or overexpressed in tumor cells [15, 18]; no surface membrane proteins were found to be immunogenic. In order to identify auto-Abs directed against putative membrane antigens, in this study we applied a membrane enrichment procedure coupled with SERPA This approach allowed us to identify ADAM10 (A Disintegrin And Metalloproteinase 10) as a membrane protein able to elicit a specific humoral response in Crc patients. We found that in Crc patients at stage III of the disease the presence of anti-ADAM10 auto-Abs is associated with a favourable prognosis, and that the antiADAM10 serological reactivity reflects the increased expression of the immature non-functional ADAM10 isoform in the tumor cells of the patients. The increase of the ADAM10-immature isoform expression is likely to be immunogenic and to contribute to the reduction of net ADAM10 activity, which is a beneficial condition that may be instrumental in the limitation of cancer progression
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
