Single-Cell RNA Sequencing Reveals Heterogeneity in the Tumor Microenvironment between Young-Onset and Old-Onset Colorectal Cancer.

BACKGROUND: The incidence of sporadic young-onset colorectal cancer (yCRC) is increasing. Compared with old-onset colorectal cancer (oCRC), yCRC has different clinical and molecular characteristics. However, the difference in the tumor microenvironment (TME) between yCRC and oCRC remains unclear. METHODS: Fourteen untreated CRC tumor samples were subjected to single-cell RNA sequencing analysis. RESULTS: B cells and naïve T cells are enriched in yCRC, while effector T cells and plasma cells are enriched in oCRC. Effector T cells of yCRC show decreased interferon-gamma response and proliferative activity; meanwhile, Treg cells in yCRC show stronger oxidative phosphorylation and TGF-ß signaling than that in oCRC. The down-regulated immune response of T cells in yCRC may be regulated by immune and malignant cells, as we observed a downregulation of antigen presentation and immune activations in B cells, dendritic cells, and macrophages. Finally, we identified malignant cells in yCRC and oCRC with high heterogeneity and revealed their interactions with immune cells in the TME. CONCLUSIONS: Our data reveal significant differences of TME between yCRC and oCRC, of which the TME of yCRC is more immunosuppressive than oCRC. Malignant cells play an essential role in the formation of the suppressive tumor immune microenvironment.

miR-421 promotes the viability of A549 lung cancer cells by targeting forkhead box O1.

MicroRNA (miR)-421 has been reported to serve various important roles in numerous types of cancer, including neuroblastoma and gastric cancer. However, to the best of our knowledge, few reports have determined the role of miR-421 in lung cancer. The aim of the current study was to analyze the expression levels of miR-421 in A549 lung cancer cells, to determine the target gene of miR-421, and to investigate the function and mechanism of miR-421 in cellular cytotoxicity. miR-421 expression levels were analyzed in A549 lung cancer cells using reverse transcription-quantitative PCR, a MTT assay was performed to determine the effect of miR-421 on A549 cell cytotoxicity and the protein expression levels of forkhead box O1 (FOXO1) were determined via western blotting. The target gene of miR-421 was predicted and verified using TargetScan and a dual-luciferase reporter assay, respectively. The results revealed that miR-421 expression levels were significantly upregulated in A549 lung cancer cell lines compared with the normal cells (P<0.01). Additionally, it was discovered that miR-421 promoted A549 cell viability (P<0.01) compared with A549 transfected with negative control. miR-421 was also identified to bind to the 3'-untranslated region of FOXO1. In A549 cells transfected with miR-421-mimics, the expression levels of phosphorylated (p)-AKT, p-glycogen synthase kinase-3ß, p-retinoblastoma and cyclin D1 were significantly upregulated (P<0.01), whereas the expression levels of FOXO1 and p21 were significantly downregulated (P<0.01) compared with the control group. In conclusion, the results of the present study suggested that miR-421 may promote the viability of A549 lung cancer cells by targeting FOXO1 and modulating cell cycle, indicating that targeting miR-421 and FOXO1 may represent future therapeutic strategies for the treatment of patients with lung cancer.

[Changes of T Cell Subsets and Their Relationship with Clinical Features and Prognosis in Patients with Acute Leukemia].

OBJECTIVE: To analyze the relationship between T cell subsets and clinical data. METHODS: mononuclear cells were collected from 103 patients with acute leukemia (AL) and 28 healthy volunteers, and percentage changes of CD3+CD4+, CD3+CD8+ and CD4+ CD25+ Foxp3+ cell subsets were assayed by flow cytometory. Relationship between the T subsets and clinical features of the patients was analyzed. RESULTS: Ratio of CD3+ T cells decreased more significantly in patients with >50% blast cells than that in patients with <50% blast cells, while the ratio of Treg between the 2 groups was not significantly different. Treg increased more statistically significantly in the patients with CD34+ leukemia cell than that with CD34- leukemia cells. In constrast to the relationship between prognosis and immune cells in the patients from 3 groups (low, intermediate and high-risk group) it was found that Treg cells increased more significantly in high-risk group than that in low-risk group. By continuously monitoring immune cells in 18 patients, it was found that Treg cells gradually increased during the first 3 courses of chemotherapy, then began to decreased in the 4th course, finally approached gradually to the normal value in the 6th course, and this change correlated with the clinical remission after chemotherapy. Treg cell number in the patients with AL was significantly higher than that in healthy controls, and Treg cell number during the onset and recurrence was significantly higher than that in the period of complete remission (continuous remission for over 6 months). Compared with the changes of immune cell number between different types of disease, it was found that Treg cells were increased more significantly in acute myeloid leukemia (AML) than that in acute lymphoblastic leukemia (ALL). Proportion of Treg cells, Treg/CD4 decreased more significantly after the 1st course of chemotherapy in the group with complete remission (CR) than that in the group without CR. The complete remission rate and recurrence rate were 68.9% and 20% respectively in the group with >10% Treg cells, while the complete remission rate and recurrence rate were 85.7% and 7.69% respectively in the group with.<10% Treg cells. In comparison of the 6 recurrent patients with 32 patients with sustained CR, it was found that the ratio of Treg cells and Treg/CD4 was increased more significantly in the patients with relapse than that with CR and in control group. CONCLUSION: Dynamic change of Treg cells in the peripheral blood was closely related with clinical feature, recurrence and prognosis in the patients with acute leukemia.