Activation of human monocyte/macrophage cytotoxicity by IL-2/IFN gamma is linked to increased expression of an antitumor receptor with specificity for acetylated mannose

Features of hematological and immune disorders in the combined treatment of breast cancer patients with the risk of development of late radiation damage

Background. Breast cancer (BC) is one of the most common forms of malignant neoplasms among the female population of Ukraine. The widespread use of radiation therapy in the treatment of BC, along with the improvement of treatment efficiency, inevitably leads to an increase in the probability of early and/or late radiation injuries (LRI), which puts before scientists the task of a detailed study of this problem and the search for ways to prevent the development of LRI.The body’s reaction to the development of a malignant neoplasm and to antitumor treatment is largely determined by the state of homeostatic mechanisms, in the regulation of which one of the key roles is played by the immune system. Recently, special attention has been focused on the role of immune inflammatory responses in the pathogenesis of LRI in cancer patients. All of the above determines the urgency of finding a differential approach to immunocorrective therapy as a prevention of the development of LRI. Рurpose – to determine the characteristics of changes in hematological indicators and the subpopulation composition of lymphocytes during immunocorrective therapy as a prevention of the development of LRI in patients with BC. Materials and Methods. 55 patients with BC were examined. The patients were divided into groups: the comparison group (n=13) – patients with BC with the risk of developing LRI who were given standard therapy, the main group (n=15) – patients with BC with the risk of developing LRI who were given immunocorrective therapy against the background of standard treatment. The control group (n=27) consisted of patients with BC without the risk of developing LRI. The groups were comparable in terms of age and disease stage. Results. Immunocorrective therapy increased the number of erythrocytes, hemoglobin level, CD19+-, CD3+CD8+-lymphocytes, NK-cells, CRP, IL-6, IL-2 and TNF-α in patients of the main group. In patients of the comparison group, after treatment, lower levels of erythrocytes, hemoglobin, lymphocytes, the relative number of CD8+-T-lymphocytes, CD19+-B-lymphocytes and higher levels of the relative number of eosinophils, monocytes, neutrophils, cytokine levels, and CRP were found in comparison with the indicators of patients, who underwent immunocorrective treatment. In patients with BC of the main group, immunocorrection reduces systemic changes that can contribute to the development of late radiation damage and recurrence of the oncological process. The inclusion of immunocorrective therapy with the use of melatonin had a positive effect on the hematological and immune indicators of patients. Conclusions. Immunocorrective therapy in patients at risk of developing LRI optimized immune and hematological parameters: it contributed to an increase in the number of erythrocytes by 1.25 times, hemoglobin level by 1.6 times, CD19+- (1.5 times), CD3+CD8+-lymphocytes (1.1 times), and a decrease in NK cells (1.77 times), CRP by 2.19 times, IL-6 by 1.8 times, IL-2 by 2.13 times, and TNF-α by 3 times, 22 times. It was found that in patients with BC with the possibility of developing LRIwithout immunotherapy, lower levels of erythrocytes (by 1.15 times), hemoglobin (by 1.13 times), lymphocytes (by 1.3 times), and the relative number of CD8+ were observed after treatment - T lymphocytes (1.4 times), CD19+ B lymphocytes (6.5 times) and higher levels of relative numbers of eosinophils, monocytes, neutrophils, cytokine levels (1.5 times) and CRP (2.1 times) in comparison with the indicators of patients who underwent immunocorrective treatment. The appointment of immunocorrective therapy with melatonin in a daily dose of 9 mg during radiation treatment for patients with BC with the risk of developing LRI led to the normalization of hematoimmune indicators, a significant decrease in the systemic inflammatory reaction.

Interferon-γ upregulates Δ42PD1 expression on human monocytes via the PI3K/AKT pathway

BACKGROUND

We recently identified a novel alternatively spliced isoform of human programmed cell death 1 (PD-1), named Δ42PD1, which contains a 42-base-pair in-frame deletion compared with the full-length PD-1. Δ42PD1 is likely constitutively expressed on human monocytes and down-regulated in patients infected with human immunodeficiency virus type 1 (HIV-1). The mechanism underlying the regulation of Δ42PD-1 expression in monocytes remains unknown.

METHODS

By flow cytometry, we investigated the effect of Interferon-gamma (INF-γ) on the expression of Δ42PD1 in primary human monocytes as well as monocytic cell lines THP-1 and U937 cells. In addition, signaling pathway inhibitors and Δ42PD1-specific blocking antibody were used to explore the pathway involved in INF-γ-induced Δ42PD1 upregulation, and to elucidate the relationship between Δ42PD1 and TNF-α or IL-6 production by INF-γ primed monocytes in response to pre-fixed E. coli. Furthermore, we assessed T-cell proliferation, activation and cytokine production as enriched CD4⁺ T cells were co-cultured with THP-1 or U937 cells, with or without Δ42PD1-blocking antibody.

RESULTS

Treatment of human peripheral blood mononuclear cells (PBMCs) with IFN-γ resulted in an approximately 4-fold increase in the expression of Δ42PD1 on monocytes. Similarly, IFN-γ upregulates Δ42PD1 expression on human monocytic cell lines THP-1 and U937, in a time- and dose-dependent manner. IFN-γ-induced Δ42PD1 upregulation was abolished by JAK inhibitors Ruxolitinib and Tasocitinib, PI3K inhibitor LY294002, and AKT inhibitor MK-2206, respectively, but not by STAT1 inhibitor and MAPK signaling pathway inhibitors. JAK, PI3K-AKT, and MAPK signaling inhibitors abolished effectively the production of TNF-α and IL-6 in INF-γ-primed monocytes in response to pre-fixed E. coli. In contrast, Δ42PD1-specific blocking antibody did not affect the IFN-γ-induced priming effect. Furthermore, the MFI ratio of Δ42PD1 to full-length PD-1 (PD-1 Δ/F ratio) was significantly and positively correlated with TNF-α (P =  0.0289, r = 0.6038) produced by circulating CD14⁺ monocytes in response to pre-fixed E. coli. Notably, Δ42PD1 blockage significantly inhibited CD4⁺ T-cells proliferation and cytokine production in the co-culture conditions.

CONCLUSIONS

We demonstrated that IFN-γ increases Δ42PD1 expression on human monocytes via activating the PI3K/AKT signaling pathway downstream of JAKs, and that the PD-1 Δ/F ratio is a potential biomarker to predict the functional state of monocytes. Notably, we revealed the Δ42PD1 play a role in T-cell regulation, providing a novel potential approach to manipulate adaptive immune response.

Active hexose correlated compound potentiates the antitumor effects of low-dose 5-fluorouracil through modulation of immune function in hepatoma 22 tumor-bearing mice

BACKGROUND/OBJECTIVES

A variety of immunomodulators can improve the efficacy of low-dose chemotherapeutics. Active hexose correlated compound (AHCC), a mushroom mycelia extract, has been shown to be a strong immunomodulator. Whether AHCC could enhance the antitumor effect of low-dose 5-fluorouracil (5-FU) via regulation of host immunity is unknown.

MATERIALS/METHODS

In the current study Hepatoma 22 (H22) tumor-bearing mice were treated with PBS, 5-FU (10 mg·kg^-1·d^-1, i.p), or AHCC (360 mg·kg^-1·d^-1, i.g) plus 5-FU, respectively, for 5 d. CD3⁺, CD4⁺, CD8⁺, and NK in peripheral blood were detected by flow cytometry. ALT, AST, BUN, and Cr levels were measured by biochemical assay. IL-2 and TNFα in serum were measured using the RIA kit and apoptosis of tumor was detected by TUNEL staining. Bax, Bcl-2, and TS protein levels were measured by immunohistochemical staining and mRNA level was evaluated by RT-PCR.

RESULTS

Diet consumption and body weight showed that AHCC had no apparent toxicity. AHCC could reverse liver injury and myelosuppression induced by 5-FU (P < 0.05). Compared to mice treated with 5-FU, mice treated with AHCC plus 5-FU had higher thymus index, percentages of CD3⁺, CD4⁺, and NK cells (P < 0.01), and ratio of CD4⁺/CD8⁺ (P < 0.01) in peripheral blood. Radioimmunoassay showed that mice treated with AHCC plus 5-FU had the highest serum levels of IL-2 and TNFα compared with the vehicle group and 5-FU group. More importantly, the combination of AHCC and 5-FU produced a more potent antitumor effect (P < 0.05) and caused more severe apoptosis in tumor tissue (P < 0.05) compared with the 5-FU group. In addition, the combination of AHCC and 5-FU further up-regulated the expression of Bcl-2 associated X protein (Bax) (P < 0.01), while it down-regulated the expression of B cell lymphoma 2 (Bcl-2) (P < 0.01).

CONCLUSIONS

These results support the claim that AHCC might be beneficial for cancer patients receiving chemotherapy.

Enhancement of Th1 type cytokine production and primary T cell activation by PBI-1393

In previous reports, we have shown that PBI-1393 (formerly BCH-1393), N,N-Dimethylaminopurine pentoxycarbonyl D-arginine, stimulates cytotoxic T-lymphocyte (CTL) responses both in vitro and in vivo in normal immune status and immunosuppressed mice. Additionally, PBI-1393 was tested for anticancer activity in syngeneic mouse experimental tumor models and it displayed significant inhibition of tumor outgrowths when given in combination with sub-therapeutic doses of cytotoxic drugs (cyclophosphamide, 5-fluorouracil, doxorubicin and cis-platinum). However, the mechanism of action of PBI-1393 was still unknown. Here, we report that PBI-1393 enhances IL-2 and IFN-gamma production in human activated T cells by 51% and 46% respectively. PBI-1393 increases also IL-2 and IFN-gamma mRNA expression as shown by RT-PCR. The physiological relevance of IL-2 and IFN-gamma gene modulation by PBI-1393 is illustrated by the advantageous increase of T cell proliferation (39+/-0.3% above control) and human CTL response against prostate (PC-3) cancer cells (42+/-0.03%). The enhancement of human T cell proliferation and CTL activation by PBI-1393 demonstrates that this compound potentiates the immune response and in this regard, it could be used as an alternative approach to IL-2 and/or IFN-gamma therapy against cancer.

Comparison of hexose acetate-specific receptors isolated from human leukocytes showing competitive inhibition of human CD56+NK and LAK cytotoxicity

Specific cytotoxicity of human CD56+NK and LAK cells was quantitatively inhibited by acetylated mannose, galactose and glucose (Scand. J. Immunol., in press). The respective NK cell receptors were isolated from human leukocyte lysates by affinity chromatography based on 60% deacetylated penta-acetates of mannose, galactose and glucose. All three affinity isolates contained a main component with +/- 87 kDa molecular mass exhibiting about the same patterns of isoforms at pI 4.90, 4.75, 4.60 and 4.50 in isoelectric focusing. Moreover, preincubation of tumor target cells with the three 87-kDa receptors revealed very similar inhibitory potentials for human NK and LAK cytotoxicity showing dose-dependent inhibition between 20 (no inhibition) and 700 pmol/ml (100% inhibition) receptor concentration. The data support the assumption that the three affinity isolates contain the same type of receptor directed against a unique epitope common to acetylated mannose, galactose and glucose.

Anti-(transforming growth factor beta) antibodies with predefined specificity inhibit metastasis of highly tumorigenic human xenotransplants in nu/nu mice

Monoclonal antibodies (mAb) were prepared against conjugated transforming growth factor beta 1 (TGF beta 1) peptides: amino acid positions 48-60 and positions 86-101. Two antibodies, mAb 16-3G1 [anti-(48-60)] and mAb 5-2G6 [anti-(86-101)] cross-reacted with native TGF beta 1, -beta 2 and -beta 3 (16-3G1) or only with native TGF beta 1 (5-2G6). Both mAb were used to characterize TGF beta-mediated effects on the metastatic potential in nude mice of human carcinoma cell line SLU-1 and its metastatic subline SLU-M1. Autocrine TGF beta 1-mediated up-regulation of cell proliferation and its suppression by anti-TGF beta antibodies in vitro was recorded for SLU-M1 cells whereas SLU-1 cell proliferation in vitro appeared to be refractory to anti-TGF beta antibodies and exogenous TGF-beta 1. However, the potential of s.c. tumours to develop distant metastases in nude mice was about the same for both cell lines. Development of primary tumours and distant metastases could be suppressed by treatment of mice with anti-TGF beta antibodies. Thus we assume that the metastatic potential of tumour cells is independent of TGF beta-mediated growth-regulation effects in vitro. The anti-TGF beta-induced suppression of tumour progression and metastasis in nude mice might rather result from stimulation of the immune surveillance. TGF beta-mediated autocrine down-regulation of MHC-unrestricted cytotoxicity of activated human monocytes and CD56+ LAK cells and its reversion by anti-TGF beta antibodies could be readily demonstrated. In all our experimental series, the neutralizing potential of both anti-TGF beta antibodies, though directed against opposite sites of the TGF beta 1 molecule, was very similar.

Chemospecificity and cross-reactivity of target cell recognition by human CD56+ NK and LAK cells

Inhibition of specific cytotoxicity of highly purified (> 95%) human CD56+ NK and LAK cells against K562 tumour cells was studied with various sugar acetates. Maximum inhibitory specificity was obtained with 60%-deacetylated penta-acetates of mannose, galactose, glucose, or 80%-deacetylated penta-O-acetate of N-acetyl neuraminic acid. The inhibition was strictly dosedependent and 100% inhibition was achieved in the concentration range of 500-1000 nmoles/ml with all four sugar acetate samples. Enhancement of specific cytotoxicity in the presence of rhamnogalacturonan (RG; 500 ng/ml), acting as a bridging molecule, was also inhibited in a dose-dependent manner with the same inhibitory specificity and within the same concentration range indicating involvement of the same number of sugar acetate-specific receptors. Moreover, formation of lytic CD56+ effector cell/tumour cell (E/T) conjugates was equally well inhibited whereas formation of total E/T conjugates was only partially inhibited (NK: 44-73%; LAK: 46-50%). E/T conjugate formation in the presence of RG was enhanced. Inhibition of the enhancement of formation of lytic E/T conjugates in the presence of RG was again completely accomplished with the same inhibitory specificity and within the same concentration ranges as recorded for E/T conjugate formation in the absence of RG. However, inhibition of total E/T conjugate formation was again only partially achieved at the given concentrations. The data support the assumption of an NK cell receptor with specificity for acetylated carbohydrate moieties on target cells or on bridging molecules such as RG.

Nitric oxide production by chicken macrophages activated by Acemannan, a complex carbohydrate extracted from Aloe vera

Cultures of normal chicken spleen cells and HD11 line cells produce nitric oxide (NO) in response to Acemannan, a complex carbohydrate derived from the Aloe vera plant. Neither cell type produced detectable amounts of NO in response to similar concentrations of yeast mannan, another complex carbohydrate. Nitric oxide production was dose dependent and inhibitable by the nitric oxide synthase inhibitor NG-methyl-L-arginine. In addition, the production of NO was inhibited by preincubation of ACM with concanavalin A in a dose-dependent manner. These results suggest that ACM-induced NO synthesis may be mediated through macrophage mannose receptors, and macrophage activation may be accountable for some of the immunomodulatory effects of ACM in chickens.

Identification of a mannose-acetate-specific 87-kDa receptor responsible for human NK and LAK activity

Target cell recognition and cytotoxicity of human CD56+ NK and LAK cells is readily inhibited by acetylated mannose. Two respective NK cell receptor candidates were isolated from human leukocyte lysates by mannose acetate affinity chromatography. The 87-kDa receptor showed sequence homologies with lactoferrin and the 59-kDa receptor represented a complex of two Ca-binding proteins MRP-8 and MRP-14 reportedly expressed only by cells of myeloid origin. The 87-kDa receptor exhibited heterogeneity in isoelectric focusing and behaved entirely differently from lactoferrin. Preincubation of tumor target cells with the 87-kDa receptor inhibited competitively target cell recognition and cytotoxicity of human CD56+ NK and LAK cells.

Enhancement of MHC-unrestricted cytotoxic activity of human CD56+ CD3- natural killer (NK) cells and CD3+ T cells by rhamnogalacturonan: target cell specificity and activity against NK-insensitive targets

Rhamnogalacturonan-mediated enhancement of MHC-unrestricted cytotoxicity was studied with freshly isolated CD56+CD3- natural killer (NK) cells, interleukin-2 (IL-2)-activated CD56+ lymphokine-activated killer (LAK) cells und IL-2/anti-CD3-activated T cells as effector cells using NK-sensitive and NK-insensitive tumor cells as targets. The rhamnogalacturonan fractions IM, IP, and IQ were prepared from commercially available extracts of Viscum album. The dose/response relation of IM, IP, and IQ demonstrated the presence of various concentrations of cytotoxicity-enhancing compounds in all three fractions that were identified as rhamnogalacturonans by degradation studies with poly-alpha-D-galacturonidase (EC 3.2.1.15) and alpha-1,6-rhamnosidase (EC 3.2.1.40). Specific cytotoxicity of all three effector cell populations as well as the respective rhamnoagalacturonan-mediated cytotoxicity enhancement was readily inhibited in a dose-dependent manner by 60%-deacetylated mannose pentaacetate. Rhamnogalacturonan-mediated enhancement of cytotoxicity of fresh CD56+ NK cells was also observed with four of five NK-insensitive tumor cells as targets, indicating that the effector-cell/tumor-cell bridging activity of rhamnogalacturonans renders NK-insensitive targets susceptible to NK-mediated lysis. Moreover, the rhamnogalacturonan-mediated cytotoxicity enhancement became even more prominent when lymphokine-activated CD56+ LAK and CD3+ T cells were assayed with the NK-insensitive tumor cell targets.