Interleukin-6 (IL-6) production in carcinoma of the cervix

Interleukin-6 and indoleamine-2,3-dioxygenase as potential adjuvant targets for Papillomavirus-related tumors immunotherapy

High-risk Human papillomavirus (HPV) infections represent an important public health issue. Nearly all cervical malignancies are associated with HPV, and a range of other female and male cancers, such as anogenital and oropharyngeal. Aiming to treat HPV-related tumors, our group developed vaccines based on the genetic fusion of the HSV-1 glycoprotein D (gD) with the HPV-16 E7 oncoprotein (gDE7 vaccines). Despite the promising antitumor results reached by gDE7 vaccines in mice, combined therapies may increase the therapeutic effects by improving antitumor responses and halting immune suppressive mechanisms elicited by tumor cells. Considering cancer immunosuppressive mechanisms, indoleamine-2,3-dioxygenase (IDO) enzyme and interleukin-6 (IL-6) stand out in HPV-related tumors. Since IL-6 sustained the constitutive IDO expression, here we evaluated the therapeutic outcomes achieved by the combination of active immunotherapy based on a gDE7 protein-based vaccine with adjuvant treatments involving blocking IDO, either by use of IDO inhibitors or IL-6 knockout mice. C57BL/6 wild-type (WT) and transgenic IL-6-/- mice were engrafted with HPV16-E6/E7-expressing TC-1 cells and treated with 1-methyl-tryptophan isoforms (D-1MT and DL-1MT), capable to inhibit IDO. In vitro, the 1MT isoforms reduced IL-6 gene expression and IL-6 secretion in TC-1 cells. In vivo, the multi-targeted treatment improved the antitumor efficacy of the gDE7-based protein vaccine. Although the gDE7 immunization achieves partial tumor mass control in combination with D-1MT or DL-1MT in WT mice or when administered in IL-6-/- mice, the combination of gDE7 and 1MT in IL-6-/- mice further enhanced the antitumor effects, reaching total tumor rejection. The outcome of the combined therapy was associated with an increased frequency of activated dendritic cells and decreased frequencies of intratumoral polymorphonuclear myeloid-derived suppressor cells and T regulatory cells. In conclusion, the present study demonstrated that IL-6 and IDO negatively contribute to the activation of immune cells, particularly dendritic cells, reducing gDE7 vaccine-induced protective immune responses and, therefore, opening perspectives for the use of combined strategies based on inhibition of IL-6 and IDO as immunometabolic adjuvants for immunotherapies against HPV-related tumors.

Infection by High-Risk Human Papillomaviruses, Epithelial-to-Mesenchymal Transition and Squamous Pre-Malignant or Malignant Lesions of the Uterine Cervix: A Series of Chained Events?

Wound healing requires static epithelial cells to gradually assume a mobile phenotype through a multi-step process termed epithelial-to-mesenchymal transition (EMT). Although it is inherently transient and reversible, EMT perdures and is abnormally activated when the epithelium is chronically exposed to pathogens: this event deeply alters the tissue and eventually contributes to the development of diseases. Among the many of them is uterine cervical squamous cell carcinoma (SCC), the most frequent malignancy of the female genital system. SCC, whose onset is associated with the persistent infection of the uterine cervix by high-risk human papillomaviruses (HR-HPVs), often relapses and/or metastasizes, being resistant to conventional chemo- or radiotherapy. Given that these fearsome clinical features may stem, at least in part, from the exacerbated and long-lasting EMT occurring in the HPV-infected cervix; here we have reviewed published studies concerning the impact that HPV oncoproteins, cellular tumor suppressors, regulators of gene expression, inflammatory cytokines or growth factors, and the interactions among these effectors have on EMT induction and cervical carcinogenesis. It is predictable and desirable that a broader comprehension of the role that EMT inducers play in SCC pathogenesis will provide indications to flourish new strategies directed against this aggressive tumor.

Cervical Castleman’s disease mimicking lymph node metastasis of esophageal carcinoma

Castleman’s disease (CD) is an uncommon benign lymphoproliferative disorder of unknown etiology. A rare case of cervical CD diagnosed at lymph node dissection for esophageal carcinoma is reported. An esophageal tumor was identified in a 67-year-old man during a follow-up examination after surgery for oral carcinoma. Esophagoscopy revealed a type 1 tumor in the cervical esophagus. Histology of esophagoscopic biopsies indicated squamous cell carcinoma. Contrast-enhanced computed tomography revealed swollen lymph nodes of the right cervical region. No distant metastasis was detected. Esophageal carcinoma, T2N2M0, Stage IIIA was diagnosed. Neoadjuvant chemotherapy was recommended, but the patient rejected the chemotherapy. The patient underwent laparoscopic-assisted transhiatal esophagectomy. The histopathological diagnosis was moderately differentiated squamous cell carcinoma with pT1bN0M0, Stage IA. On histology, the swollen lymph nodes of the right cervical region revealed CD. The patient’s postoperative course was relatively good.

Down-regulation of microRNA-9 leads to activation of IL-6/Jak/STAT3 pathway through directly targeting IL-6 in HeLa cell

MicroRNA‐9 (miR‐9) presents to exert distinct and even opposite functions in different kinds of tumors through targeting different cellular genes. However, its role in cervical adenocarcinoma remains uncertain. Here, we report that miR‐9 is down‐regulated in cervical adenocarcinoma due to its frequent promoter‐hypermethylation and exerts its tumor suppressor role through inhibiting several novel target genes, including interleukin‐6 (IL‐6). The promoters of miR‐9 precursors (mir‐9‐1, ‐2, and ‐3) were hypermethylated in cervical adenocarcinoma tissues. Demethylation treatment of HeLa dramatically increased the expression of mature miR‐9. Both in vitro and in vivo functional experiments confirmed that miR‐9 can inhibit the proliferation, migration, and malignant transformation abilities of HeLa cells. Bioinformatics methods and array‐based RNA expression profiles were used to screen the downstream target genes of miR‐9. Dual‐luciferase reporting assay, real‐time qPCR, and ELISA or Western blot confirmed four genes (CKAP2, HSPC159, IL‐6, and TC10) to be novel direct target genes of miR‐9. Pathway annotation analysis of the differently expressed genes (DEGs) induced by ectopic miR‐9 expression revealed the enrichment in Jak/STAT3 pathway, which is one of the downstream pathways of IL‐6. Ectopic expression of miR‐9 in HeLa inhibited Jak/STAT3 signaling activity. Moreover, such effect could be partially reversed by the addition of exogenous IL‐6. In conclusion, our results here present a tumor suppressor potential of miR‐9 in cervical adenocarcinoma for the first time and suggest that miR‐9 could repress tumorigenesis through inhibiting the activity of IL‐6/Jak/STAT3 pathway. © 2015 The Authors. Molecular Carcinogenesis, published by Wiley Periodicals, Inc.

IL-6 and related cytokines as the critical lynchpins between inflammation and cancer

Inflammatory responses play pivotal roles in cancer development, including tumor initiation, promotion, progression, and metastasis. Cytokines are now recognized as important mediators linking inflammation and cancer, and are therefore potential therapeutic and preventive targets as well as prognostic factors. The interleukin (IL)-6 family of cytokines, especially IL-6 and IL-11, is highly up-regulated in many cancers and considered as one of the most important cytokine families during tumorigenesis and metastasis. This review discusses molecular mechanisms linking the IL-6 cytokine family to solid malignancies and their treatment.

Seminal plasma enhances cervical adenocarcinoma cell proliferation and tumour growth in vivo

Cervical cancer is one of the leading causes of cancer-related death in women in sub-Saharan Africa. Extensive evidence has shown that cervical cancer and its precursor lesions are caused by Human papillomavirus (HPV) infection. Although the vast majority of HPV infections are naturally resolved, failure to eradicate infected cells has been shown to promote viral persistence and tumorigenesis. Furthermore, following neoplastic transformation, exposure of cervical epithelial cells to inflammatory mediators either directly or via the systemic circulation may enhance progression of the disease. It is well recognised that seminal plasma contains an abundance of inflammatory mediators, which are identified as regulators of tumour growth. Here we investigated the role of seminal plasma in regulating neoplastic cervical epithelial cell growth and tumorigenesis. Using HeLa cervical adenocarcinoma cells, we found that seminal plasma (SP) induced the expression of the inflammatory enzymes, prostaglandin endoperoxide synthase (PTGS1 and PTGS2), cytokines interleukin (IL) -6, and -11 and vascular endothelial growth factor-A(VEGF-A). To investigate the role of SP on tumour cell growth in vivo, we xenografted HeLa cells subcutaneously into the dorsal flank of nude mice. Intra-peritoneal administration of SP rapidly and significantly enhanced the tumour growth rate and size of HeLa cell xenografts in nude mice. As observed in vitro, we found that SP induced expression of inflammatory PTGS enzymes, cytokines and VEGF-A in vivo. Furthermore we found that SP enhances blood vessel size in HeLa cell xenografts. Finally we show that SP-induced cytokine production, VEGF-A expression and cell proliferation are mediated via the induction of the inflammatory PTGS pathway.

Inflammatory signaling and aryl hydrocarbon receptor mediate synergistic induction of interleukin 6 in MCF-7 cells

The pleiotropic cytokine interleukin 6 (IL-6) is involved in immune cell homeostasis. Additionally, IL-6 expression and signaling in tumor cells have been shown to elicit both protumor and antitumor properties. There is a plethora of mechanistic knowledge regarding how IL-6 signal transduction translates to biological responses. However, there is little understanding as to what factors control IL-6 expression within a tumor cell environment. The studies presented herein show that, in MCF-7 breast and ECC-1 endocervical cancer cells, the stimulation of aryl hydrocarbon receptor (AHR) activity, in combination with IL-1beta or phorbol 12-myristate 13-acetate (PMA) treatment, results in a marked synergistic induction of IL-6 levels over what is seen without AHR activation. Chromatin immunoprecipitation experiments suggest that the regulation of IL-6 mRNA expression occurs at the chromatin level, as AHR presence on the IL-6 promoter was observed in response to treatment with AHR ligand. Synergistic induction of IL-6 expression was sustained for 72 hours, with accumulation of IL-6 protein reaching levels 4.8-fold above IL-1beta treatment alone. In addition, transcriptional regulation of the prototypic AHR responsive gene Cyp1a1 was negatively regulated by PMA and IL-1beta treatment. Silencing of RELA expression alleviated IL-1beta-mediated repression of AHR transcriptional activity, whereas PMA-mediated repression was maintained. Additionally, small interfering RNA studies reveal that AHR and RELA are necessary for synergistic induction of IL-6. The findings presented here reveal the AHR as a potential therapeutic target for selective modulation of IL-6 expression in some tumor cell types. The data also suggest a possible previously unrecognized mechanism of AHR-mediated tumor promotion.

Interplay between human papillomaviruses and dendritic cells

The design of the human papillomavirus (HPV) infection cycle is tightly fitted to the differentiation program of its natural host, the keratinocyte. This has important consequences for the role of antigen-presenting cells in the priming of antiviral immunity. The confinement of HPV infection to epithelia puts the epithelial dendritic cell, the Langerhans cell (LC), in charge of the induction of T cell-dependent immunity. Because HPV-infected keratinocytes cannot reach the regional lymphoid organs, and HPV-infection of LCs does not result in viral gene expression, priming of antiviral T cells exclusively depends on cross-presentation of viral antigens by the LC. Sensitization of the immune system in the regional lymphoid organs elicits systemic anti-HPV immunity as well as intraepithelial immune surveillance by memory-type intraepithelial T cells and locally produced antibodies. The high rate of spontaneous rejections of high-risk HPV-infections and HPV-positive premalignant lesions indicates that in general the LC-driven antigen presentation machinery is capable of raising an effective immune defense against HPV. Epidemiological studies also reveal that a decrease in the vigilance of the immune system is readily exploited by HPV to escape immune destruction, resulting in persistent infections and development of HPV-positive cancers. In view of the inherent antigenicity of HPV, immune intervention strategies constitute a promising approach for both the prevention and the therapeutic treatment of HPV-induced diseases. Importantly, the mechanisms that govern the induction and effector phases of the intraepithelial immune surveillance against HPV must be taken into account when designing such strategies.

Detection of epidermal growth factor receptor mRNA in peripheral blood of cervical cancer patients

OBJECTIVE

Epidermal growth factor receptor (EGFR) has been reported to be expressed by immunohistochemistry in invasive cervical cancers. We evaluated the feasibility of detecting EGFR mRNA by EGFR-based reverse transcription polymerase chain reaction (RT-PCR) in peripheral blood of patients with cervical cancer.

METHODS

Expression of EGFR mRNA, cytokeratin (CK)-19 mRNA, and CK-20 mRNA was examined by RT-PCR in 12 human cervical cancer cell lines. All 12 cell lines expressed both EGFR mRNA and CK-19 mRNA, but only 4 of 12 (33.3%) cell lines expressed CK-20 mRNA. Peripheral blood samples from 20 healthy donors and 45 cervical cancer patients were also examined.

RESULTS

In peripheral blood from 20 healthy donors, neither EGFR mRNA nor CK-20 mRNA was expressed, but CK-19 mRNA was expressed in 13 of 20 (65%). In contrast, EGFR mRNA was expressed in 12 of 45 (26.7%) patients with cervical cancer (P = 0.0071, 2 test, patient vs control). On the other hand, expression of EGFR was observed in 98% of tumor tissues by immunohistochemistry. CK-19 mRNA and CK-20 mRNA were found in 35 of 45 (77.8%) and 0 of 45 (0%) patients, respectively (NS, chi(2) test, patient vs control). The rate of detection of EGFR mRNA in peripheral blood correlated with FIGO stage (P = 0.049).

CONCLUSION

Both CK-19 mRNA and CK-20 mRNA showed no diagnostic value as markers of circulating tumor cells in cervical cancers. However, EGFR mRNA in blood might be a useful marker of circulating tumor cells in cervical cancers.

Response to IL-6 of HPV-18 cervical carcinoma cell lines

The human papillomavirus type 18 (HPV-18) upstream regulatory region (URR) controls cell type-specific expression of the viral oncoproteins E6 and E7. The HPV-18 URR is active in the cervical carcinoma cell line HeLa but inactive in the hepatoma cell line HepG2. C/EBPss (NF-IL-6) was shown to participate as an important regulator in HPV transcription dependent on the cell type. The finding that C/EPBss is critical for HPV-18 URR activity and that C/EPBss is induced by IL-6 offers the opportunity of manipulating HPV activity by specific cytokine treatment. In this report, we show that treatment with IL-6 results in activation of HPV-18 URR activity in HepG2 cells. In contrast, the HPV-18 URR is not inducible by IL-6 in three cervical carcinoma cell lines. In all three cell lines we found decreased expression of the IL-6 receptor compared to the IL-6-responsive HepG2 cells, whereas the level of expression of the signal transduction component gp130 is present in all cells. These results suggest that cervical carcinoma cells may circumvent the IL-6-induced cellular defense mechanism through downregulation of the IL-6-receptor.

Increased IL-6 and IL-8 levels in cervicovaginal secretions of patients with cervical cancer

OBJECTIVE

Conflicting data exist on IL-6 production by human papillomavirus (HPV) immortalized cell lines and several cervical carcinoma cell lines. However, no information has been reported on the levels of cytokines in cervicovaginal washings in relation to cervical neoplasia. The aim of this study was to investigate whether local production of IL-6 could be found and whether the level of this cytokine was related to the severity of cervical neoplasia. IL-8 was measured to obtain additional information on an inflammatory cytokine with possible epithelial origin.

METHODS

Cervicovaginal washings and sera were obtained from 35 patients with invasive cervical cancer, 62 patients with cervical intraepithelial neoplasia (CIN), and 25 control subjects. IL-6 and IL-8 levels were determined by ELISA. HPV DNA in cervical smears was detected by a HPV-16-specific PCR method and additionally by CPI/IIG PCR. Histological analysis of the inflammatory infiltrate was performed on hematoxylin-eosin-stained tissue sections.

RESULTS

In the patients with cervical cancer, those with CIN, and the controls, the median IL-6 concentration in cervicovaginal washings was 171 pg/ml (interquartile range: 54-780), 22 pg/ml (<2-73), and < 2 pg/ml (<2-<2), respectively. For IL-8, the levels were 2756 pg/ml (1651-7107), 489 pg/ml (248-1158), and 631 pg/ml (346-897), respectively. In most subjects the local levels were much higher than in serum. Local IL-6 and IL-8 levels were significantly higher in patients with cervical carcinoma compared with CIN patients and controls. Likewise, local IL-6 levels were increased in patients with CIN compared with controls. No relation was found between cytokine levels and CIN grade or between cytokine levels and the inflammatory infiltrate scored by histological analysis.

CONCLUSIONS

There is local production of IL-6 and IL-8 in cervicovaginal secretions, and the production of IL-6 was related to the severity of cervical neoplasia.

Establishment and characterization of a new HPV-negative squamous cell carcinoma cell line (Yumoto) from the human uterine cervix

A new cell line, Yumoto, derived from a squamous cell carcinoma of the uterine cervix, was established from serially transplanted tumor tissues in nude mice. Monolayer cultured cells were polygonal and formed pavement-like sheet. They showed a piling-up tendency and were devoid of contact inhibition. Electron micrographs demonstrated the presence of microvilli on the cell surface, abundant tonofilaments in the cytoplasm, and the connection with desmosomes. These electron micrographical characteristics of Yumoto cells were consistent with those of squamous cell origin. Yumoto cells were highly tumorigenic in BALB/c nude mice and produced a well-differentiated squamous cell carcinoma of keratinizing type which closely resembled to the original tumor tissues in nude mice. The presence of HPV DNA was examined using polymerase chain reaction and Southern blot analysis, but no known types of HPV DNA could be detected. Exons 2 through 11 of the p53 gene were analyzed by direct DNA sequencing, revealing a homozygous mutation at codon 281 in exon 8, GAC to CAC (Asp-->His). Furthermore, physical p53-gene deletion was demonstrated by dual-color fluorescence in situ hybridization. This cell line is useful for studying the carcinogenesis of cervical carcinoma and for investigating the biological characteristics of a HPV-negative and mutated p53 squamous cell carcinoma of the uterine cervix.

Role of interleukin-6 in uncoupling of bone in vivo in a human squamous carcinoma coproducing parathyroid hormone-related peptide and interleukin-6

OCC tumor has been established from a human squamous carcinoma associated with humoral hypercalcemia of malignancy (HHM) and shown to overproduce parathyroid hormone-related peptide (PTHrP) and cause aggressive hypercalcemia when implanted into nude rats. In the present study, we have demonstrated by reverse transcription-polymerase chain reaction and Northern blot analysis that OCC tumor also overexpressed interleukin 6 (IL-6) mRNA and that tumor-bearing animals exhibited a marked increase in plasma IL-6 as well as PTHrP concentrations. When a monoclonal antibody against human IL-6 was injected to block the activities of tumor-derived IL-6, bone loss in tumor-bearing animals was significantly prevented. Quantitative bone histomorphometric analysis revealed that treatment with anti-IL-6 antibody caused a substantial decrease in both osteoclast number and eroded surface (as parameters of bone resorption) and also a significant increase in the mineral apposition rate, but little effect on the osteoblastic surface. These results provide in vivo evidence suggesting that in tumors coproducing IL-6 and PTHrP, IL-6 is involved not only in the acceleration of osteoclastic bone resorption but also, at least in part, in the suppression of osteoblastic functions in HHM syndrome.