FANCA promotes lung adenocarcinoma progression and is a potential target for epitope vaccine immunotherapy

Background: FANCA mutations have been detected in a variety of cancers and found to be pro-carcinogenic. However, no functional studies have been identified regarding the involvement of FANCA in the occurrence and the immune response of LUAD.

Methods: The mRNA expression and overall survival rates of FANCA were evaluated by the TIMER, PrognoScan and TCGA database in LUAD tissues, and FANCA expression was further validated by clinical serum samples using ELISA. The correlation between FANCA and immune infiltration level was investigated via TISIDB database and CIBERSORT algorithm. The Kaplan-Meier plotter was used to further evaluate the prognostic value based on the expression levels of FANCA in related immune cells. Then, the influence of FANCA knockout on the proliferation, migration, and invasion of A549 and H1299 cells was validated using CCK8, cloning formation, and Transwell assays. Subsequently, HLA-A2-restricted FANCA antigenic Peptides were predicted and synthesized by NetMHC4.0 and SYFPEITHI, and DCs were induced and cultured in vitro. Finally, DCs loaded with HLA-A2-restricted FANCA antigenic Peptides were co-cultured with autologous peripheral blood lymphocyte to generate specific CTLs. The killing effects of different CTLs on LUAD cells were studied.

Results: The results showed that high levels of FANCA in patients with LUAD were significantly correlated with worse OS survival, which was correlated with age, clinical stage, pathological T stage, M stage, and N stage in LUAD. Knockdown of FANCA in A549 and H1299 cells significantly inhibited proliferation, metastasis, and invasion in vitro. In addition, FANCA was significantly related to immune infiltrate, genomic alterations and TMB. FANCA expression infuenced the prognosis of LUAD patients by directly affecting immune cell infltration. Finally, HLA-A2-restricted FANCA antigenic Peptides were synthesized. And FANCA 146-154 (SLLEFAQYL) antigenic peptide exhibit a stronger affinity for DCs, and induce CTLs to produce stronger targeted killing ability for LUAD cells at an effector-to-target ratio of 40:1.

Conclusion: These results demonstrated that the elevation of FANCA promotes malignant phenotype of LUAD, and the potential peptide P2 (SLLEFAQYL) derived from FANCA may be used as an epitope vaccine for the treatment of LUAD.