In vitro upregulation of carcinoembryonic antigen expression by combinations of cytokines

Interleukin-6 trans-signaling increases the expression of carcinoembryonic antigen-related cell adhesion molecules 5 and 6 in colorectal cancer cells

Background

Colorectal cancer (CRC) is among the five most frequent causes for cancer-related deaths in Europe. One of the most important tumor-associated antigens for CRC is carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5), which is involved in cell adhesion, migration, anoikis, tumor invasion and metastasis. Its family member CEACAM6 is also upregulated in adenomas and carcinomas of the colon and an independent predictor of poor survival. Previous studies have reported a link between upregulation of CEACAM5 and interleukin-6 (IL-6). IL-6 plays an important role in CRC progression, and signaling is mediated via two pathways (classic and trans-signaling). However, this link could not be confirmed by other studies, and the role of IL-6 trans-signaling in the CEACAM5 upregulation has not been elucidated. Moreover, the impact of IL-6 on the expression of CEACAM6 has not yet been examined.

Methods

The expression of IL-6, IL-6 receptor (IL-6R), glycoprotein (gp) 130, CEACAM5 and CEACAM6 was analyzed by RT-PCR, Western blot, flow cytometry or qPCR. Colon cell lines were incubated with IL-6 or Hyper-IL-6 (mediating IL-6 trans-signaling), and subsequently, the expression of CEACAMs was determined by qPCR or Western blot. FLLL31, an inhibitor of the phosphorylation of signal transducer and activator of transcription-3 (STAT3), was used to determine the role of STAT3 phosphorylation.

Results

We confirmed that colon carcinoma cell lines express IL-6 and IL-6R. We observed only a weak upregulation of CEACAM5 and CEACAM6 by classic IL-6 signaling, but a strong increase by IL-6 trans-signaling. This upregulation depended on the phosphorylation of STAT3.

Conclusions

Our data show the upregulation of the tumor-associated antigens CEACAM5/6 by trans-signaling of the pro-inflammatory cytokine IL-6. This mechanism may contribute to the tumor-promoting role of IL-6 and could therefore be a target for therapeutic intervention in particular by specific inhibitors such as sgp130Fc.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1950-1) contains supplementary material, which is available to authorized users.

Possible association of CEA expression with oxyphilic change but not with C-cell hyperplasia in Hashimoto's thyroiditis

Reactive C-cell hyperplasia (CCH) has been observed in cases of autoimmune Hashimoto's thyroiditis; however, its occurrence in Graves' disease, the other major autoimmune disorder, has not yet been investigated. On the other hand, although Carcinoembryonic Antigen (CEA) serum levels have been reported elevated in patients with autoimmune thyroid disease (ATD), the source of CEA production at the cellular level is not elucidated. The aim of this study was to evaluate CCH and CEA immunohistochemical expression and comparatively analyze them in 136 ATD cases (107 Hashimoto's and 29 Graves' disease cases) and 20 cases of nodular hyperplasia (NH). Immunohistochemistry using monoclonal antibodies to chromogranin and CEA was performed. A scoring system for CCH and semiquantitative evaluation for CEA expression were applied. C-cell hyperplasia was absent in NH cases. In contrast, it was detected in 11% of ATD cases being more frequently observed in Hashimoto's (12.1%) than Graves' disease (6.8%) CCH associated to male sex and older age of Hashimoto's patients. CEA was detected only in ATD cases (33.8%), in C-cells and in follicular cells as well, being more frequently detected in Graves' (44.8%) than Hashimoto's (30.8%) disease. An interesting finding was an emerging possible association of CEA expression with oxyphilic change but not with C-cell hyperplasia in Hashimoto's thyroiditis. No significant correlation was established between CCH and CEA follicular cell expression in neither disease. In conclusion, C-cell hyperplasia and CEA expression may be encountered in the setting of Hashimoto's thyroiditis and Graves' disease.

Influence of cytokines, monoclonal antibodies and chemotherapeutic drugs on epithelial cell adhesion molecule (EpCAM) and LewisY antigen expression

MoAbs against tumour-associated antigens (TAA) may be useful for the treatment of colorectal cancer. Since an increased expression of TAA may lead to enhanced antibody-dependent cellular cytotoxicity we examined whether the cytokines IL-2, IL-4, IL-6, IL-10, IL-12, interferon-alpha (IFN-alpha), IFN-gamma, granulocyte-macrophage colony-stimulating factor, macrophage colony-stimulating factor and tumour necrosis factor-alpha can influence EpCAM and LewisY expression on the surface of the colorectal carcinoma cell lines HT29, LoVo and SW480. We found that only IFN-alpha increased significantly whereas IL-4 decreased both EpCAM and LewisY expression. IFN-gamma significantly increased LewisY expression only. When tumour cells were treated with MoAb, the LewisY-specific MoAb BR55-2 down-regulated LewisY antigen expression, whereas MoAb 17-1A, which binds to EpCAM, up-regulated this TAA after 3 days of culture. The cytokines IFN-alpha or IFN-gamma combined with MoAb 17-1A enhanced further slightly the expression of EpCAM. In additional experiments with chemotherapeutic drugs commonly used for the treatment of colorectal cancer, we found that 5-fluorouracil, mitomycin-C and oxaliplatin up-regulated EpCAM and LewisY antigen expression. Raltitrexed enhanced LewisY and down-regulated EpCAM expression, whereas CPT-11 had no influence at all. The highest expression for EpCAM on HT29 cells was achieved by the combination of IFN-alpha, 5-fluorouracil and MoAb 17-1A. Our results may be useful for defining combinations of biological and chemotherapeutic drugs for the treatment of colorectal cancer. Further trials should evaluate to what extent these combinations enhance antibody-dependent cellular cytotoxicity.

Redirected perforin-dependent lysis of colon carcinoma by ex vivo genetically engineered CTL

The redirection of autologous lymphocytes to predefined tumor target Ags has considerable potential for the immunotherapeutic treatment of cancer; however, robust experimental systems for comparing various approaches have not been developed. Herein, we have generated a single chain variable domain anti-carcinoembryonic Ag (CEA) Fcepsilon receptor I gamma-chain fusion (scFv anti-CEA) receptor and demonstrated high-level expression of this chimeric receptor in naive mouse T lymphocytes by retroviral gene transduction. These gene-modified CTL were able to lyse CEA+ targets and secrete high levels of IFN-gamma following Ag stimulation. Depletion studies demonstrated that specific tumor cell cytotoxicity was mediated by gene-modified CD8+ T cells. Importantly, in increasingly stringent tests of efficacy in vivo, transduced CTL were sequentially shown to reject CEA+ colon carcinoma cells in a Winn assay and then reject established s.c. colon carcinoma in scid or syngeneic mice. Furthermore, using gene-targeted and scFv anti-CEA receptor-transduced donor CTL, perforin and IFN-gamma were demonstrated to be absolutely critical for the eradication of colon carcinoma in mice. In summary, we have developed a highly efficient gene transfer system for evaluating chimeric receptor expression in cytotoxic lymphocytes. This series of experiments has revealed the utility of scFv anti-CEA chimeras in providing mouse T cells the capacity to reject colon carcinoma in an Ag- and perforin-specific manner.