Targeted therapy of DC-CIK cells in renal cell carcinoma

Abstract

CIK cells are a heterogeneous population of exceptional T lymphocytes with CD3+CD56+ cells as the primary effectors. CIK cells in combination with DCs have exhibited promising clinical effects on patients with RCC as evidenced by several completed or ongoing clinical trials. However, recurrence and non-responsiveness is still a challenging issue in some patients. In order to improve the antitumor response of DC-CIK cells against RCC, we investigated the effect of anti-CD40 and anti-CTLA-4 antibodies on DC-CIK cells against RCC cell lines. Our analysis showed that, a) anti-CD40 antibody (G28.5) increased the CD3+CD56+ effector cells of CIK cells by promoting the maturation and activation of DCs, b) G28.5 also increased CTLA-4 expression in CIK cells via DCs, but the increase could be hindered by the CTLA-4 inhibitor (ipilimumab), c) adding ipilimumab was also able to significantly increase the proportion of CD3+CD56+ cells in DC-CIK cells, d) anti-CD40 antibodies predominated over anti-CTLA-4 antibodies for cytotoxicity, apoptotic effect and IFN-γ secretion of DC-CIK cells against RCC cells, e) after ipilimumab treatment, the population of Tregs in CIK cells remained unaffected, but ipilimumab combined with G28.5 significantly reduced the expression of CD28 in CIK cells. To summarize, we suggest that the agonistic anti-CD40 antibody rather than CTLA-4 inhibitor may improve the antitumor response of DC-CIK cells, particularly in RCC. Alghough the exact mechanisms of CTLA-4 signaling are still under considerable debate, CTLA-4 has been considered one of the most promising immune checkpoints to be targeted clinically. Nevertheless, the clinical advantages associated with CTLA-4 inhibitors can be offset by the potentially severe immune-related adverse events, including autoimmune thyroid dysfunction. So we next investigated the candidate genes and signaling pathways involved in autoimmune thyroid dysfunction related to anti-CTLA-4 therapy. DEGs were extracted from the intersection of genes from GEO datasets and text mining. The functional enrichment was performed by GO annotation and KEGG pathway analysis. PPI network, module enrichment, and hub gene identification were constructed and visualized by STRING and Cytoscape software. A total of 22 and 17 integrated human DEGs in hypothyroidism and hyperthyroidism groups related to anti-CTLA-4 therapy were identified, respectively. Functional enrichment analysis revealed 24 GO terms and 1 KEGG pathway in the hypothyroid group and 21 GO terms and 2 KEGG pathways in the hyperthyroid group. After PPI network construction, the top five hub genes associated with hypothyroidism were extracted, including ALB, MAPK1, SPP1, PPARG, and MIF, whereas genes associated with hyperthyroidism were ALB, FCGR2B, CD44, LCN2, and CD74. The identification of the candidate key genes and enriched signaling pathways provides potential biomarkers for autoimmune thyroid dysfunction related to anti-CTLA-4 therapy for future diagnosis and management. Taken together, our studies about the critical parts of immunotherapy, CIK cells and immune checkpoint blockade, could provide potential approaches to improve the clinical response of cancer patients.