Correlation between IL-10 gene expression and HPV infection in cervical cancer: a mechanism for immune response escape

Dendritic cells treated with HPV16mE7 in a three-dimensional model promote the secretion of IL-12p70 and IFN-γ

Although the human papillomavirus (HPV) DNA therapeutic vaccine represents a promising approach to the prevention and treatment of cervical cancer, the mechanism of the HPV DNA vaccine is poorly understood. Moreover, current strategies have met with only limited success in preclinical and dendritic cell-based (DC-based) clinical research. In addition, two-dimensional (2-D) DC monolayers poorly mimic the physiology function in vivo. We used a three-dimensional (3-D) DC culture model in vitro to explore the immune mechanism of the HPV DNA vaccine. DCs were generated from peripheral blood monocytes with interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF). The cells, growing in 3-D collagen gel, were treated with pcDNA3.1-HPV16mE7 in vitro for 48 h. Compared to DCs treated with E7 in a 2-D culture model, the expression of co-stimulatory molecules CD80 and CD40 were significantly increased in the 3-D model (p<0.05), and a remarkable increase of IL-12 p70 was observed. However, we did not detect any obvious change in IL-10 in 3-D culture. In addition, we found that IFN-γ expression increased when HPV16mE7-DC cells were co-cultured with T-cells for 96 h in the 3-D model, and HPV16mE7-DCs stimulated the proliferation of T lymphocytes more efficiently in the 3-D model than in the 2-D model (p<0.05). These results suggest that DCs in 3-D culture model have a notable effect on the enhancement of the HPV16 DNA vaccine's immune reaction and indicate that the DC-based 3-D model is a novel approach to study the HPV vaccine.

Interleukin-10 production by tumor infiltrating macrophages plays a role in Human Papillomavirus 16 tumor growth

BACKGROUND

Human Papillomavirus, HPV, is the main etiological factor for cervical cancer. Different studies show that in women infected with HPV there is a positive correlation between lesion grade and number of infiltrating macrophages, as well as with IL-10 higher expression. Using a HPV16 associated tumor model in mice, TC-1, our laboratory has demonstrated that tumor infiltrating macrophages are M2-like, induce T cell regulatory phenotype and play an important role in tumor growth. M2 macrophages secrete several cytokines, among them IL-10, which has been shown to play a role in T cell suppression by tumor macrophages in other tumor models. In this work, we sought to establish if IL-10 is part of the mechanism by which HPV tumor associated macrophages induce T cell regulatory phenotype, inhibiting anti-tumor activity and facilitating tumor growth.

RESULTS

TC-1 tumor cells do not express or respond to IL-10, but recruit leukocytes which, within the tumor environment, produce this cytokine. Using IL-10 deficient mice or blocking IL-10 signaling with neutralizing antibodies, we observed a significant reduction in tumor growth, an increase in tumor infiltration by HPV16 E7 specific CD8 lymphocytes, including a population positive for Granzyme B and Perforin expression, and a decrease in the percentage of HPV specific regulatory T cells in the lymph nodes.

CONCLUSIONS

Our data shows that in the HPV16 TC-1 tumor mouse model, IL-10 produced by tumor macrophages induce regulatory phenotype on T cells, an immune escape mechanism that facilitates tumor growth. Our results point to a possible mechanism behind the epidemiologic data that correlates higher IL-10 expression with risk of cervical cancer development in HPV infected women.

Tissue tumor marker expression in smokers, including serum cotinine concentrations, in women with cervical intraepithelial neoplasia or normal squamous cervical epithelium

OBJECTIVE

The purpose of this study was to investigate correlations between smoking and serum cotinine, respectively, and tumor marker expression in cervical intraepithelial neoplasia (CIN) and normal epithelium.

STUDY DESIGN

Women (n = 228) with cervical biopsy specimens that ranged histologically from normal to carcinoma in situ (CIN III) were included. Expression of 11 tumor markers with possible relevance in cervical neoplasms was studied. Smoking habits were recorded, and serum was assessed for cotinine concentrations.

RESULTS

No differences were found in tumor marker expression in normal epithelium between smokers and nonsmokers. The tumor suppressors p53 and fragile histidine triad and the immunologic marker interleukin-10 were underexpressed, and the tumor markers cyclooxygenase-2 and Ki-67 were overexpressed in smoking, compared with nonsmoking, women with CIN and particularly in all fertile women.

CONCLUSION

The molecular pattern indicates that smoking exerts unfavorable effects in cervical neoplasia. This provides biologic evidence of smoking being a true cofactor in cervical neoplasia.

Tumor immunosuppressive environment: effects on tumor-specific and nontumor antigen immune responses

The interactions between cancer cells and host immune cells in tumoral microenvironments create an immunosuppressive network that promotes tumor growth, protects the tumor from immune attack and attenuates the efficacy of immunotherapeutic approaches. The development of immune tolerance becomes predominant in the immune system of patients with advanced-stage tumors. Several mechanisms have been described by which tumors can suppress the immune system, including secretion of cytokines, alterations in antigen-presenting cell subsets, costimulatory and coinhibitory molecule alterations and altered ratios of Tregs to effector T cells. It is well demonstrated that these mechanisms of immunosuppression can impair tumor specific immune responses. However, it is not well established whether this immunosuppressive environment can affect immune responses to nontumor antigens, specifically in regard to priming and the development of memory. The few existing studies indicate that responses to nontumor antigens seem unaffected, although there is still a deep lack of understanding of this phenomenon. This is an important issue regarding patient endurance and quality of life. Here, we review the existing evidence on immunosuppression promoted by tumors, with particular attention to its impact on specific immune responses. Understanding these interactions can help us subvert tumor-induced tolerance and optimize anti-tumor therapy.

A comprehensive microarray-based DNA methylation study of 367 hematological neoplasms

BACKGROUND

Alterations in the DNA methylation pattern are a hallmark of leukemias and lymphomas. However, most epigenetic studies in hematologic neoplasms (HNs) have focused either on the analysis of few candidate genes or many genes and few HN entities, and comprehensive studies are required.

METHODOLOGY/PRINCIPAL FINDINGS

Here, we report for the first time a microarray-based DNA methylation study of 767 genes in 367 HNs diagnosed with 16 of the most representative B-cell (n = 203), T-cell (n = 30), and myeloid (n = 134) neoplasias, as well as 37 samples from different cell types of the hematopoietic system. Using appropriate controls of B-, T-, or myeloid cellular origin, we identified a total of 220 genes hypermethylated in at least one HN entity. In general, promoter hypermethylation was more frequent in lymphoid malignancies than in myeloid malignancies, being germinal center mature B-cell lymphomas as well as B and T precursor lymphoid neoplasias those entities with highest frequency of gene-associated DNA hypermethylation. We also observed a significant correlation between the number of hypermethylated and hypomethylated genes in several mature B-cell neoplasias, but not in precursor B- and T-cell leukemias. Most of the genes becoming hypermethylated contained promoters with high CpG content, and a significant fraction of them are targets of the polycomb repressor complex. Interestingly, T-cell prolymphocytic leukemias show low levels of DNA hypermethylation and a comparatively large number of hypomethylated genes, many of them showing an increased gene expression.

CONCLUSIONS/SIGNIFICANCE

We have characterized the DNA methylation profile of a wide range of different HNs entities. As well as identifying genes showing aberrant DNA methylation in certain HN subtypes, we also detected six genes--DBC1, DIO3, FZD9, HS3ST2, MOS, and MYOD1--that were significantly hypermethylated in B-cell, T-cell, and myeloid malignancies. These might therefore play an important role in the development of different HNs.

TLR9 signaling promotes tumor progression of human lung cancer cell in vivo

Toll like receptor 9 (TLR9) was identified mainly in cells of the immune system, and CpG oligonucleotides (CpG ODN), which induces signaling through TLR9, are currently under investigation as adjuvants in clinical therapies against cancer. However, accumulating data suggested that functional TLR9 was also expressed in tumor cells and the effects of TLR9 signaling on the progression of tumor cells remain undefined. Our previous study demonstrated that the TLR9 signaling could significantly enhance the metastatic potential of human lung cancer cells in vitro. Here we carefully evaluated the direct effect of TLR9 signaling on tumor progression of human lung cancer cells in vitro and in vivo. We observed that TLR9 agonist CpG ODN could robustly enhance the tumor progression of 95D cells which expressed high level of TLR9 in nude mice. Furthermore, the CpG ODN could effectively induce the proliferation and IL-10 secretion of 95D cells in vitro. Finally, we demonstrated that CpG ODN could significantly elevate the tumor progression of TLR9 modifying 95C cells in vitro and in vivo, which could be dramatically abrogated by the inhibitory CpG ODN. Our findings indicated that the TLR9 signaling could promote the tumor progression of human tumor cells, which might provide novel insight into the implications for CpG based anti-tumor therapies.