SEREX analysis for tumor antigen identification in a mouse model of adenocarcinoma
T A Hampton1, R M Conry, M B Khazaeli
1Gene Therapy Center, and Department of Medicine, University of Alabama at Birmingham, 35294, USA.
Abstract:
Evaluation of immunotherapy strategies in mouse models of carcinoma is hampered by the limited number of known murine tumor antigens (Ags). Although tumor Ags can be identified based on cytotoxic T-cell activation, this approach is not readily accomplished for many tumor types. We applied an alternative strategy based on a humoral immune response, SEREX, to the identification of tumor Ags in the murine colon adenocarcinoma cell line MC38. Immunization of syngeneic C57BL/6 mice with MC38 cells by three different methods induced a protective immune response with concomitant production of anti-MC38 antibodies. Immunoscreening of an MC38-derived expression library resulted in the identification of the endogenous ecotropic leukemia virus envelope (env) protein and the murine ATRX protein as candidate tumor Ags. Northern blot analysis demonstrated high levels of expression of the env transcript in MC38 cells and in several other murine tumor cell lines, whereas expression in normal colonic epithelium was absent. ATRX was found to be variably expressed in tumor cell lines and in normal tissue. Further analysis of the expressed env sequence indicated that it represents a nonmutated tumor Ag. Polynucleotide immunization with DNA encoding the env polypeptide resulted in strong and specific antibody responses to this self Ag in all immunized mice. Thus, SEREX offers a rapid means of identifying tumor Ags in murine cancer models.
Insights
Identifying new tumor antigens (Ags) in mouse cancer models is crucial for immunotherapy. Researchers used the SEREX method to find novel tumor Ags, including the ecotropic leukemia virus envelope protein, in colon adenocarcinoma, aiding future cancer research.
Area of Science:
- Oncology
- Immunology
- Molecular Biology
Background:
- Immunotherapy evaluation in mouse cancer models is limited by few known murine tumor antigens (Ags).
- Identifying tumor Ags typically relies on cytotoxic T-cell activation, which is not feasible for all tumor types.
Purpose of the Study:
- To identify novel tumor antigens in the murine colon adenocarcinoma cell line MC38 using the SEREX (Serological identification of antigens by expression cloning) strategy.
- To evaluate the potential of identified antigens as targets for immunotherapy.
Main Methods:
- Applied the SEREX strategy to the MC38 murine colon adenocarcinoma cell line.
- Immunized C57BL/6 mice with MC38 cells to induce immune responses and antibodies.
- Screened an MC38 expression library to identify proteins recognized by anti-MC38 antibodies.
- Analyzed antigen expression in tumor cell lines and normal tissues using Northern blot.
- Performed polynucleotide immunization with DNA encoding a candidate antigen.
Main Results:
- Identified the endogenous ecotropic leukemia virus envelope (env) protein and murine ATRX protein as candidate tumor Ags.
- Demonstrated high expression of the env transcript in MC38 and other murine tumor cell lines, with absent expression in normal colonic epithelium.
- Confirmed env as a nonmutated tumor antigen.
- Achieved strong and specific antibody responses against the env self-antigen via DNA immunization.
Conclusions:
- The SEREX strategy provides a rapid method for identifying tumor antigens in murine cancer models.
- The identified env protein is a promising candidate for further investigation in colon cancer immunotherapy.
- This study expands the repertoire of known murine tumor antigens, facilitating the development of novel immunotherapies.
