Aberrant expression of chemokine receptor CCR4 in human gastric cancer contributes to tumor-induced immunosuppression.

The chemokine receptor CCR4 is preferentially expressed on certain immune cells and some hematological tumor cells, which play pivotal roles in suppression of host immune response. However, the reasons for the upmodulation of CCR4 and its immune functions in solid tumors remain unclear. Herein, we aimed to determine the expression profiles of CCR4 in gastric cancer cells and its role in regulating antitumor immunity. CCR4 expression was assessed in 63 cases of gastric carcinomas by immunohistochemistry. We found cancer cells in lymphocyte-rich carcinomas more frequently showed moderate to strong positive staining for CCR4 than those in conventional carcinomas (P = 0.041), and also found a positive relationship between expression of CCR4 and tumor necrosis factor-α (P = 0.012). Stimulation of gastric cell lines with various cytokines showed that tumor necrosis factor-α uniquely upmodulated CCR4 expression through activation of nuclear factor-κB. Additional coculture experiments showed the forced expression of CCR4 in SGC-7901 cells caused a significant reduction of γ-interferon and elevation of interleukin-10 secretion in the supernatants from cocultured SGC-7901 cells and PBMCs. In addition, granzyme A production in cancer cell-cocultured CD56(+) natural killer cells was significantly downregulated. Inhibition of the overexpressed CCR4 in cancer cells by an inhibitor of CCR4, compound 39, proved to partly restore the antitumor immunity in respect of the inverse changes in those factors. Our studies suggest that the aberrant expression of CCR4 in human gastric cancer could contribute to tumor-induced immunosuppression. Conceivably, downmodulation of CCR4 expression could be a promising immunotherapy for human gastric cancer.

[Expressions of Fas, CTLA-4 and RhoBTB2 genes in breast carcinoma and their relationship with clinicopathological factors].

OBJECTIVE: The purpose of this study was to explore the clinical significance of expression of Fas, CTLA-4 and RhoBTB2 genes in breast carcinoma. METHODS: Semi-quantitative reverse transcriptive polymerase chain reaction (RT-PCR) was used to analyze the mRNA expression levels of the three genes in tumor tissues from 60 patients with primary breast cancer and normal breast tissues of 30 cases. The relationship between gene expression and clinicopathological factors were analyzed and determined. RESULTS: The relative expression levels (gray scale ratio between target gene and internal reference gene) of Fas, CTLA-4 and RhoBTB2 genes in breast carcinoma tissues were 0.699 +/- 0.285, 1.045 +/- 0.302 and 0.625 +/- 0.160, respectively. In the normal breast tissues, they were 0.502 +/- 0.178, 0.418 +/- 0.140 and 0.843 +/- 0.218, respectively. There were statistically significant differences of the expression of those three genes between carcinoma tissues and normal breast tissues (P < 0.01). The expression level of Fas in carcinoma tissues was significantly higher in lymph node matastasis positive patients (0.782 +/- 0.313) than that in node-negative patients (0.557 +/- 0.146, P < 0.01). The expression level of CTLA-4 gene in carcinoma tissues was lower in II stage patients (0.978 +/- 0.330) than that in III stage patients (1.134 +/- 0.240, P < 0.05). The expression level of RhoBTB2 gene was lower in invasive ductal carcinoma (0.597 +/- 0.157) than that in invasive lobular carcinoma (0.717 +/- 0.145, P < 0.05). There were no correlations of expression of the three genes at mRNA level and age, ER, PR, HER2 status and survival time. Furthermore, no correlation was seen among the three genes expression (P > 0.05). CONCLUSION: The expression of all the three genes at mRNA level is involved in genesis and progression of breast cancer. There exist correlations between Fas expression and axillary lymph node matastasis, CTLA-4 expression and disease stage, and RhoBTB2 expression and pathological type of breast cancer.

Elevated levels of serum soluble E-selectin in patients with chronic hepatitis B: Correlation with T lymphocyte subsets, NK cells and liver inflammation.

BACKGROUND: It has been reported that serum soluble E-selectin (sE-selectin) may be increased in some inflammatory liver diseases. The purpose of our study was to investigate changes of sE-selectin, T lymphocyte subsets, natural killer (NK) cells, and HBV load in patients with chronic hepatitis B (CHB), analyze the relationship between them, and discuss their significances. METHODS: Fifty-four patients with chronic hepatitis B and fourteen controls were studied. Serum sE-selectin, T lymphocyte subsets, NK cells, and hepatitis B virus (HBV) load were detected by enzyme-linked immunosorbent assay (ELISA), flow cytometry (FCM), and fluorescence quantitative polymerase chain reaction (FQ-PCR), respectively. RESULTS: sE-selectin level in patients with CHB increased significantly than that in controls (p<0.01). The percentages of CD4 positive cells and NK cells decreased while the percentage of CD8 positive cells increased significantly in CHB patients than in controls (p<0.01, respectively). sE-selectin level significantly related to levels of T lymphocyte subsets, NK cells, serum alanine aminotransferase (sALT) and aspartate aminotransferase (sAST) (p<0.01, respectively), but had no relationship with HBV level. CONCLUSION: The sE-selectin levels in patients with chronic hepatitis B increase significantly and correlate to liver inflammation, suggesting that sE-selectin can be considered as an additional useful marker of CHB inflammatory activity, and E-selectin may play part of role in pathogenesis of chronic hepatitis B.

[Studies on the genetic pathogenesis of myasthenia gravis caused by CTLA-4 gene polymorphism].

OBJECTIVE: To study the genetic pathogenesis of myasthenia gravis (MG) caused by cytotoxic T lymphocyte associated antigen-4 (CTLA-4) gene polymorphisms and regulation function of transcription factor. METHODS: ELISA assay was used to determine the expression level of serum sCTLA-4 in MG. Four single nucleotide polymorphisms (SNPs) of CTLA-4 at exon 1 +49, promoter -318, -1661, -1772 were analyzed by restriction fragment length polymorphism (RFLP). Transcription factor nuclear factor 1(NF-1) and c/EBPbeta binding site were confirmed by chromatin immunoprecipitation(CHIP) assay. RESULTS: It was found that the frequencies of the GG+49 genotype and G+49 allele are higher in MG patients with thymoma than those in patients of thymic hyperplasia and normal thymus subgroups. T/C-318 is not correlated with MG. The frequency of CT-1772 genotype is significantly higher in MG patients, especially in MG patients with thymoma, when compared with that in healthy controls. Meanwhile, the frequency of the G-1661 allele and GG-1661 genotype is lower in MG patients. Linkage disequilibrium (LD) between each SNPs in promoter -1772, -1661, -318 and coding sequence 1 (CDS 1) +49 is apparent. sCTLA-4 levels in patients' sera are correlated with the haplotype and genotype. T/C-1772 and A/G-1661 SNPs change the sequence of transcription factor NF-1 and c/EBPbeta binding sites. DNA variants lose site-specific binding activity of transcription factor regulated by lectin ConA and PHA. CONCLUSION: There are strong positive linkages among four SNPs. C/T-1772 and A/G-1661 polymorphisms can result in inefficient transcription of CTLA-4 gene. T>C-1772 mutation also affects gene splicing. These SNPs may constitute a factor of susceptibility to disease.