Dendritic cells (DCs) and invariant natural killer T (iNKT) cells play important roles in linking innate immunity and adaptive immunity. Mature DCs activated by Toll-like receptor (TLR) agonists directly activate iNKT cells and the iNKT ligand α-galactosylceramide (α-Galcer) can induce DC maturation, resulting in enhanced protective immune responses. In the present study, we aimed to boost anti-tumour immunity in a murine colon cancer model by synergizing DCs and iNKT cells using α-Galcer-loaded tumour cells (tumour–Gal) and the TLR9 agonist cytosine-phosphorothioate-guanine (CpG1826). The vaccine strategy was sufficient to inhibit growth of established tumours and prolonged survival of tumour-bearing mice. Importantly, the immunization induced an adaptive memory immune response as the survivors from primary tumour inoculations were resistant to a tumour re-challenge. Furthermore, injection of tumour–Gal with CpG1826 resulted in iNKT cell activation and DC maturation as defined by interferon (IFN)-γ secretion by iNKT, natural killer (NK) cells and interleukin (IL)-12 by DCs. Immunohistochemistry analysis revealed that cluster of differentiation (CD)4⁺ T-cells and CD8⁺ T-cells played important roles in anti-tumour immunity. Additionally, the vaccine redirected Th2 (T-helper cell type 2) responses toward Th1 (T-helper cell type 1) responses with increases in IL-2, IFN-γ expression and decreases in IL-4 and IL-5 expression after immunization with tumour–Gal with CpG1826. Taken together, our results demonstrated a novel vaccination by synergizing tumour–Gal and CpG1826 against murine colon cancer, which can be further developed as tumour-specific immunotherapy against human cancer.

Background: Long non-coding RNAs (lncRNAs) participate in a wide range of physiological processes, and their dysregulation is prevalent in human cancers, indicating critical roles in tumorigenesis. In intermediate- to high-risk gastrointestinal stromal tumors (GISTs), resistance to tyrosine kinase inhibitors (TKIs) remains a major therapeutic challenge. Therefore, identifying lncRNAs as potential novel therapeutic targets is of considerable interest. Methods: Three paired samples of intermediate- to high-risk GIST tissues and adjacent normal tissues were subjected to transcriptome sequencing. High-content screening (HCS) was subsequently performed to identify candidate lncRNAs with significant effects on GIST cell proliferation. Loss-of-function experiments were conducted, and cell proliferation, migration, and apoptosis were evaluated using the Cell Counting Kit-8 (CCK-8) assay, colony formation assay, Transwell migration assay, and flow cytometry, respectively. In addition, in situ hybridization (ISH) was performed on 507 primary GIST tissue specimens to examine the association between CTD-2245E15.3 expression and clinicopathological features, including progression-free survival (PFS) and overall survival (OS). Results: Transcriptome sequencing revealed 2924 upregulated and 2629 downregulated lncRNAs in GIST tissues compared with adjacent normal tissues. Based on HCS results, CTD-2245E15.3 was selected for further functional analyses. CCK-8 assays demonstrated that knockdown of CTD-2245E15.3 significantly inhibited proliferation of GIST cells. Consistently, colony formation and migratory capacity were markedly reduced in the shCTD-2245E15.3 group compared with controls. Furthermore, flow cytometric analysis showed a significant increase in apoptosis following CTD-2245E15.3 silencing. ISH analysis revealed that high CTD-2245E15.3 expression correlated with adverse clinicopathological features and poorer PFS and OS. Conclusions: Our study demonstrates that CTD-2245E15.3 promotes proliferation and migration of GIST cells and is associated with poor prognosis, highlighting its potential as a therapeutic target and diagnostic biomarker.