Neoantigens play a crucial role in cancer immunotherapy. However, the effectiveness and safety of neoantigen-based immunotherapies in patients with colorectal cancer (CRC), particularly in the Chinese population, have not been well studied. This study explored the feasibility and effectiveness of neoantigens in the treatment of CRC. Whole-exome sequencing (WES) and transcriptome sequencing were used to identify somatic mutations, RNA expression, and human leukocyte antigen (HLA) alleles. Neoantigen candidates were predicted, and immunogenicity was assessed. The neoantigens TSHZ3-L523P, RARA-R83H, TP53-R248W, EYA2-V333I, and NRAS-G12D from Patient 4 (PW4); TASP1-P161L, RAP1GAP-S215R, MOSPD1-V63I, and NAV2-D1973N from Patient 10 (PW10); and HAVCR2-F39V, SEC11A-R11L, SMPDL3B-T452M, LRFN3-R118Q, and ULK1-S248L from Patient 11 (HLA-A0201 + PW11) induced a heightened neoantigen-reactive T cell (NRT) response as compared with the controls in peripheral blood lymphocytes (PBLs) isolated from patients with CRC. In addition, we identified neoantigen-containing peptides SEC11A-R11L and ULK1-S248L from HLA-A0201 + PW11, which more effectively elicited specific CTL responses than the corresponding native peptides in PBLs isolated from HLA-A0201 + PW11 as well as in HLA-A2.1/K b transgenic mice. Importantly, adoptive transfer of NRTs induced by vaccination with two mutant peptides could effectively inhibit tumor growth in tumor-bearing mouse models. These data indicate that neoantigen-containing peptides with high immunogenicity represent promising candidates for peptide-mediated personalized therapy. Abbreviations: CRC: colorectal cancer; DCs: dendritic cells; ELISPOT: enzyme-linked immunosorbent spot; E:T: effector:target; HLA: human leukocyte antigen; MHC: major histocompatibility complex; Mut: mutant type; NGS: next-generation sequencing; NRTs: neoantigen-reactive T cells; PBMCs: peripheral blood mononuclear cells; STR: short tandem repeat; PBLs: peripheral blood lymphocytes; PBS: phosphate-buffered saline; PD-1: programmed cell death protein 1; TILs: tumor-infiltrating lymphocytes; RNA-seq: RNA sequencing; Tg: transgenic; TMGs: tandem minigenes; WES: whole-exome sequencing; WT: wild-type.

Background: The role of neoantigens in cancer immunotherapy is crucial. However, the effectiveness and safety of personalized neoantigen vaccines in colorectal cancer (CRC), especially in Chinese population, has not been well studied. This paper mainly explores the feasibility and effectiveness of personalized neoantigen vaccines in CRC treatment. Methods: Whole-exome sequencing and transcriptome sequencing were used to identify somatic mutations, RNA expression and human leukocyte antigen (HLA) alleles. Neoantigens were predicted, and the immunogenicity of neoantigen candidates was evaluated by ELISPOT in vitro. To verify the immunogenicity in vivo, neoantigen candidates from HLA-A0201+PW11 were used to immunized female 6-8-week-old HLA-A2.1/Kb-transgenic (Tg) mice. Neoantigen-reactive T cells (NRTs) were induced by immunogenic peptides from autologous HLA-A2.1/Kb to adoptive transfer transgenic mice, and C57BL/6nu/nu mice were used for in vivo antitumor response assays.Results: Compared to medium alone (no peptide) or the unrelated peptide VSV-NP43-69, the neoantigens TSHZ3-L523P, RARA-R83H, TP53-R248W, EYA2-V333I and NRAS-G12D from Patient 4 (PW4); HAVCR2-F39V, SEC11A-R11L, TASP1-P161L, RAP1GAP-S215R, MOSPD1-V63I and NAV2-D1973N from Patient 10 (PW10); and SMPDL3B-T452M, LRFN3-R118Q and ULK1-S248L from Patient 11 (PW11) induced notable peptide-specific T cell responses. The results indicated that about half of the predicted neoantigens for all 3 patients can stimulate T cell responses and antitumor effects in CRC. In addition, predicted neoantigens from PW11 (HLA-A0201) showed promising antitumor efficacy in HLA-A2.1/Kb-Tg mice and tumor-bearing mouse models.Conclusion: With the application of next-generation sequencing (NGS) sequencing of patient specimens, neoantigen prediction and a rapid immunoassay system, an evaluation system utilizing in vitro studies and in vivo transgenic and tumor-bearing mouse models can be used to screen strong immunogenic neoantigens in CRC patients. Accurate identification of neoantigens with strong immunogenicity would promote personalized cancer vaccine development.

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Gastric cancer(GC) remains the fourth-leading malignancy worldwide and has a high mortality rate.Accumulating evidence reveals that long noncoding RNAs (lncRNAs) play essential roles in tumorigenesis and metastasis and can be used as potential biomarkers for diagnosis and prognosis. The current study sought to define the lncRNA LUCAT1 and verify its malignant biological behaviors in GC. We conducted bioinformatic analysis to screen differentially expressed lncRNAs between GC tissue and paracancerous tissue. Gene expression profiles were downloaded from the National Center of Biotechnology Information Gene Expression Omnibus(GEO). Real-time quantitative polymerase chain reaction (RT-qPCR) was carried out to verify LUCAT1 expression in both GC tissue and paracancerous tissue. Furthermore, the associations between LUCAT1 and clinical features were analyzed. In addition, the malignant behaviors of LUCAT1 in GC were investigated by knocking down LUCAT1 expression in the SGC7901 and AGS cell lines. The results indicated that LUCAT1 expression was obviously upregulated in GC samples compared with paracancerous tissue samples. Moreover, the expression pattern of LUCAT1 showed close correlations with tumor diameter (P<0.001), differentiation grade (P=0.026), and lymphnode metastasis(LNM)status (P=0. 020). In vitro, shRNA-mediated knockdown of LUCAT1 expression inhibited proliferation, migration, and invasion and led to S-phase cell cycle arrest and apoptosisin GC cells. Thus, the lncRNA LUCAT1 may be used as a potential biomarker for early signs of LNM in GC and may play a crucial role in the development of GC.