Immunosuppressive Effect of Mesenchymal Stromal Cells is Enhanced by IL-1α from Oral Squamous Cell Carcinoma Cells

Productions of Th2 cytokines, IL-4 and IL-10, were enhanced via the function of IL-2 from anti-CD3 antibody-stimulated mouse spleen cells treated with caffeic acid phenethyl ester

OBJECTIVES

Interleukin (IL)-2 production by mouse spleen cells stimulated with an anti-CD3 antibody is significantly enhanced by caffeic acid phenethyl ester (CAPE), a major constituent of Chinese propolis (CP). In this study, we evaluated the functional significance of IL-2 in CAPE-treated activated spleen cells.

METHODS

Mouse spleen cells were stimulated with an anti-CD3 monoclonal antibody in the presence of CAPE. Cytokine production was examined using an enzyme-linked immunosorbent assay (ELISA). Messenger RNA level expression was examined via reverse transcription quantitative polymerase chain reaction (RT-PCR). IL-2 function was assessed using IL-2 and a neutralizing antibody. Spleen cell subsets were identified and characterized using flow cytometry.

RESULTS

CAPE treatment of anti-CD3 antibody-stimulated spleen cells reduced IFN-γ production, then enhanced IL-2 production, followed by enhancement of IL-4 and IL-10 production. The Th2 cytokine production enhancing effects of CAPE were completely abolished by addition of an anti-IL-2 neutralizing antibody. In the absence of CAPE, exogenously added IL-2 could enhance IL-4 production to a lesser degree, but did not stimulate IL-10 production, in stimulated spleen cells. Interestingly, CAPE significantly reduced the proportions of CD4+ and CD8+ cells, and increased those of CD4-CD8- cells among anti-CD3 stimulated spleen cells, in the presence or absence of anti-IL-2 neutralizing antibody treatment.

CONCLUSIONS

CAPE reduced IFN-γ production, then enhanced IL-4 and IL-10 production via the activity of specifically elevated IL-2 in stimulated spleen cells. CAPE exerted these effects in a CD4- CD8- cell specific manner.

Enhanced production of IL-2 from anti-CD3 antibody-stimulated mouse spleen cells by caffeic acid phenethyl ester, a major component of Chinese propolis

OBJECTIVES

We evaluated the immune-modulatory effects of Chinese propolis (CP) and its major constituent, caffeic acid phenethyl ester (CAPE), on the cytokine production of anti-CD3 antibody-stimulated mouse spleen cells.

METHODS

Mouse spleen cells stimulated by anti-CD3 monoclonal antibody were co-cultured with CP, CAPE, and HC030031, a specific antagonist of the TRPA1 Ca2+-permeable cation channel. Cytokine production was assayed by enzyme-linked immunosorbent assay. Interleukin (IL)-2 mRNA expression was examined by reverse transcription-quantitative polymerase chain reaction.

RESULTS

In stimulated spleen cells treated with 1/16,000 CP diluent, IL-2 production was markedly enhanced, while IL-4 and IL-10 productions were not significantly affected. In contrast, interferon (IFN)-γ, IL-6, and IL-17 productions were markedly reduced. These effects of CP were reproduced by the CAPE treatment. A time-course observation demonstrated that, compared to control cells, IL-2 mRNA expression and production were significantly enhanced in the spleen cells stimulated by CAPE; however, IL-2 production was markedly delayed compared to that in the untreated control cells. The enhancement of IL-2 production by CAPE was scarcely alleviated by the addition of HC030031. These effects of CAPE upon IL-2 mRNA production were abolished in spleen cells without anti-CD3 antibody stimulation.

CONCLUSIONS

CAPE is an important regulator of CP for cytokine regulation in anti-CD3 antibody-stimulated spleen cells. The agent specifically reduced IFN-γ, IL-6, and IL-17 and slightly enhanced Th2 cytokine production while significantly enhancing IL-2 production at the transcriptional level.

Enhanced production of IL-2 from anti-CD3 antibody-stimulated mouse spleen cells by artepillin C, a major component of Brazilian green propolis

OBJECTIVES

In this report, we attempt to clarify the immune modulatory effects of Brazilian green propolis (BGP) and its major component, artepillin C, on the cytokine production of anti-CD3 antibody-stimulated mouse spleen cells. We also estimate the physiological mechanism affecting artepillin C's upon the cells.

METHODS

Male C3H/HeN mouse spleen cells stimulated by antiCD3 monoclonal antibody were co-cultured with BGP, artepillin C, and HC030031, a transient receptor potential ankyrin 1 (TRPA1) Ca²⁺ channel antagonist. The synthesis of interferon (IFN)-γ, interleukin (IL)-6, IL-17, IL-4, IL-10, and IL-2 was assayed by enzyme-linked immunoassay. The expression of IL-2 mRNA and the protein product were examined by reverse transcription-quantitative polymerase chain reaction and Western blot analyses, respectively.

RESULTS

The production of IL-2 was markedly enhanced, while that of IL-4 and IL-10 was not significantly affected; by contrast, the production of IFN-γ, IL-6, and IL-17 was significantly reduced in the antibody-stimulated spleen cells treated with BGP at a non-cytostatic concentration. These effects were reproduced in the cells treated with artepillin C. The expression of IL-2 mRNA was unaffected; however, that of the protein was significantly enhanced in the artepillin C-treated cells compared to untreated control cells. The enhancement of protein expression and the production of IL-2 by artepillin C was significantly alleviated by adding HC030031.

CONCLUSIONS

Artepillin C is an important regulator of cytokine synthesis from activated spleen cells. The agent specifically augmented the expression of IL-2 via the Ca²⁺-permeable cation channel, TRPA1, at least in part, at the translational or secretion levels.

Augmented secretion of IL-1α from mouse oral squamous cell carcinoma (OSCC) cells caused by serum deprivation and hypoxia promotes immune suppressive activity of mesenchymal stromal cells

OBJECTIVES

We have previously reported that mouse oral squamous carcinoma (OSCC), Sq-1979-1, produces interleukin (IL)-1α, which specifically enhances the immunosuppressive activity of co-cultured mesenchymal stromal 10T1/2 cells. This study assessed the conditions promoting the production of IL-1α in Sq-1979-1 cells, which could further enhance the immunosuppressive function of 10T1/2 cells, and evaluated its expression in OSCC tissues.

METHODS

The expression of IL-1α was examined by RT-PCR, western blotting, and enzyme-linked immune sorbent assay (ELISA). The interferon (IFN)- γ-producing capability of anti-CD3 antibody-stimulated mouse spleen cells co-cultured with 10T1/2 cells and conditioned medium (CM) from Sq-1979-1 cells was examined by ELISA. The function of IL-1α was examined using an anti-IL1α antibody. Immunohistochemical analysis of the OSCC tissues was performed.

RESULTS

The production of IL-1α from Sq-1979-1 cells was synergistically enhanced in lower serum (0.5% or 1.0% FBS) at the transcriptional level, and under hypoxia (1.0% oxygen) at the release level compared to that in the control medium supplemented with 10% FBS under normoxia. The IFN-γ-producing capability of stimulated spleen cells co-cultured with 10T1/2 cells was significantly reduced in the CMs prepared with the lower serum or under hypoxia. These functions of CMs were completely abolished by the anti-IL-1α antibody. The expression of IL-1α in OSCC tissues was prominent in the midst of a carcinomatous cellular lesion or a nearby necrotic lesion, where a supply deficiency could occur.

CONCLUSIONS

IL-1α production by Sq-1979-1 cells was synergistically augmented under low serum and hypoxic conditions, which could promote the immunosuppressive activity of mesenchymal cells.

Immunomodulatory aspects in the progression and treatment of oral malignancy

Inflammation substantially affects the risk of oral malignancy. Pro-inflammatory cytokine, interferon (IFN)-γ, confers anti-tumor activity using several different mechanisms. Conversely, higher expression of interleukin (IL)-17 is associated with worse prognosis. Monocyte chemotactic protein (MCP)-1 correlates positively with poor long-term survival of head and neck squamous cell carcinoma (HNSCC) patients. IL-1α affects cancer associated fibroblasts and macrophages, and promote several malignant phenotypes including immune suppression. Some anti-inflammatory cytokines, including IL-10 and transforming growth factor (TGF)-β, relate to pro-tumoral activities. Among immune checkpoint modulators, programmed death (PD-)1 and PD-ligand (L)1 facilitate oral squamous cell carcinoma (OSCC) cell evasion from immune surveillance, and the expression status of these has a prognostic value. OSCCs contain tumor associated macrophages (TAMs) as major stromal cells of their tumor microenvironment. Among the two distinctive states, M2 macrophages support tumor invasion, metastasis and immune suppression. Crosstalk between TAMs and OSCC or cancer-associated fibroblasts (CAF) plays an important role in the progression of OSCC. Clinical trials with blocking antibodies against IL-1α or melanoma-associated antigens have been reported as therapeutic approaches against OSCCs. The most promising approach activating antitumor immunity is the blockade of PD-1/PD-L1 axis. Manipulating the polarization of pro-tumorigenic macrophages has been reported as a novel therapeutic approach.