The identification of tumour antigens recognized by patients with Duke’s B (Stage II) reactive colorectal cancers using SEREX
Abstract
Colorectal cancer (CRC) is one of the most commonly diagnosed cancers in both men and women, posing a serious demographic and economic burden worldwide. In the UK, CRC affects one in every twenty people and it is often detected once well-established and after it has spread beyond the bowel (Stage IIA-C and Stage IIIA-C). A diagnosis at such advanced stages is associated with poor treatment response and survival. However, studies have identified two sub-groups of post-treatment CRC patients – those with good outcome (reactive disease) and those with poor outcome (non-reactive disease). Evidence indicates the presence of an effective immune response differentiates between those patients who respond well to treatment and those who do not. To investigate these underlying mechanisms we used the serological analysis of cDNA recombinant libraries (SEREX) technique to determine which antigens are recognised by patients in each group. Immunoscreening a healthy donor testes cDNA library with sera from three patients with Duke’s B reactive disease led to the identification of five antigens. These were (1) the immunoglobulin heavy constant gamma 3 (G3m marker), IGHG3 gene, located on chromosome 14 at 14q32.33, which encodes IgG3, and was recognised by sera from patients CC005 and CC014; (2) the immunoglobulin heavy constant gamma 2, IGHG2 gene, located on chromosome 14 at 14q32.33 and recognised by CC014 sera; while (3) CYB5R3, (4) RPL37A and (5) SLC34A2 were recognised by CC005, CC014 and CC014 sera respectively. CYB5R3 is a NADH-cytochrome b5 reductase 3 protein which has been shown to be upregulated in lung tissue with a RAS mutation in mice. Ribosomal protein L37a (RPL37A) has previously been shown to be upregulated in astrocytomas and to have a general association with lifetime glioblastoma survival and overall glioblastoma survival. Solute carrier family 34 member 2 (SLC34A2) encodes a protein which acts as a pH-sensitive sodium-dependent phosphate transporter. SLC34A2 has been shown to be upregulated in breast and ovarian cancers and it is suggested that SLC34A2 is involved in the process of carcinogenesis, making it an attractive target in therapeutic strategies and also as a diagnostic biomarker. Although other antigens were found, and their sequences identified, all were unknown and not found in the databases. RT-PCR analysis of the Duke’s B colon cancer cell line SW480 showed consistent expression of BCP-20. Although, expression of SSX2, NY-ESO-1, TSP50, HAGE and RAGE were detected, the data was not easily reproductible. Further optimisation of the PCR conditions and primer pairs would be necessary to confirm these findings. We hope in the future we can disern the role of these antigens in the inflammatory immune responses associated with reactive Dukes’ B colon cancer which would help us better understand the mechanisms which underlie effective anti-tumour responses post-surgery. It may also be that RPL37A is a biomarker for patient survival in colorectal cancer and this would be worthy of further investigation.Citation
Boncheva, V.B. (2013) 'The identification of tumour antigens recognized by patients with Duke’s B (Stage II) reactive colorectal cancers using SEREX'. MPhil thesis. University of Bedfordshire.Publisher
University of BedfordshireType
Thesis or dissertationLanguage
enDescription
A thesis submitted to the Faculty of Creative Arts, Technologies & Science, University of Bedfordshire, in fulfilment of the requirements for the degree of Master of Philosophy.Collections
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