Evaluation of macrophage antiviral activity in patients affected by neoplasia

In Vitro Interleukin-8 Production by Monocytes Treated with Lithium Chloride from Breast Cancer Patients

Aims and background

Since interleukin-8 (IL-8) has a suppressive effect on hematopoiesis, lithium induces leukocytosis and granulocytosis and mononuclear cells are defective in patients affected by neoplastic disease, we analyzed IL-8 production by monocytes obtained from patients with non-metastatic breast cancer (BCaMO) and metastatic breast cancer (BCaM1) and the effect of lithium chloride (LiCI) on these cells. Lithium salt compounds are used to limit the degree and duration of neutropenia in patients receiving chemotherapy for cancer and acute leukemia. Lithium influences the hematopoietic system, which is known to be regulated by numerous cytokines including IL-8.

Methods

We selected three groups of subjects (15 per group): patients affected by BCaMO, BCaM1 and healthy donors (HD) matched for sex and age. IL-8 release was assessed in supernatants of lipopolysaccharide (LPS) and/or LiCI-treated monocyte cultures.

Results

Monocytes from BCaM1 released higher IL-8 levels than monocytes from BCaMO (P <0.0001); the IL-8 levels of both groups were significantly higher (P <0.0001) than those of HD. In vitro LiCI treatment reduced IL-8 production by monocytes obtained from all subjects compared to the same cells when untreated or LPS treated. The suppressive effect of LiCI on IL-8 production by monocytes from breast cancer patients was particularly marked in monocytes from BCaMO with respect to those from BCaM1. LPS treatment increased the IL-8 production more in BCaM1 monocytes than in BCaMO monocytes. Moreover, combined LPS/LiCI treatment of monocytes significantly (P <0.0001) downregulated the release of IL-8 compared to treatment with LPS alone.

Conclusions

Our data demonstrate that monocytes from BCaM1 release larger amounts of IL-8 than monocytes from BCaMO and from HD. Lithium was able to downregulate IL-8 production by monocytes from different subgroups. Further studies are needed to clarify if the improvement of the hematopoietic system in vivo observed following lithium therapy could reside, at least in part, in the ability of lithium to downregulate this chemokine.

Evaluation of interleukin-18 production by in vitro differentiated monocytes from breast cancer patients

Interleukin-18 (IL-18) is a multifunctional cytokine which may play an important role in cancer. In previous studies it has been reported that mononuclear cells from breast cancer patients were defective in cytokine production. In this report we examined in vitro IL-18 release by monocytes (Mo) and differentiated monocytes (Mphi) for 6 or 12 days from healthy donors (HD) and nonmetastatic breast cancer (BCa) patients prior to chemo-, hormonal or radiotherapy. Our results show no production of this cytokine by Mo and Mphi for 6 days in all the experimental conditions. HD Mphi cultured for 12 days were responsive to lipopolysaccharides only after 24 h of treatment, while significantly (p<0.05) lower amounts of IL-18 were produced by BCa Mphi cultures in the same experimental conditions. Since BCa Mphi are defective in IL-18 production, and this cytokine elicits in vivo protective antitumor effects, we hypothesize a future possibility for the use of IL-18 in cancer therapy.

In vitro effect of lithium chloride on interleukin-15 production by monocytes from IL-breast cancer patients

Lithium salt compounds are used to limit the degree and duration of neutropenia in patients receiving chemotherapy for cancer. Interleukin-15 (IL-15) is a cytokine which possesses promoting activities on hematopoiesis and is also involved in antitumor response, activating NK, CTL and LAK cells. In this study we analyzed IL-15 production by monocyte cultures treated with lithium chloride (LiCl). Monocytes were obtained from patients affected by non-metastatic and metastatic breast cancer. LiCl treatment induced IL-15 production by monocytes mainly from non-metastatic patients. Combined lipopolysaccharide/LiCl treatment of monocyte cultures up-regulated IL-15 release compared to those treated with LPS alone (p<0.0001). The modulation of LiCl-induced IL-15 could counteract the immunosuppression state of cancer patients, which should be taken into account when developing new immunotherapeutic strategies.

Generation of superoxide anion and candidacidal activity by lipopolysaccharide-treated macrophages from patients affected by neoplasia

Macrophages, derived from in vitro cultured monocytes from both healthy donors and patients affected by metastatic breast cancer, treated or not with Escherichia coli lipopolysaccharide (LPS), were tested for phagocytosis and intracellular killing of Candida albicans and superoxide anion release. We found a marked impairment in intracellular killing closely linked to the lack of superoxide production in macrophages from patients affected by neoplasia treated or not with LPS. On the other hand, the LPS treatment significantly enhanced the phagocytic activity of all the macrophage populations tested, except for phagocytes obtained from patients affected by neoplasia and differentiated in autologous serum.

Modulation of the intrinsic antiviral activity by Escherichia coli endotoxin in macrophages from patients with neoplasia

Macrophages from patients with breast cancer showed an impairment of their antiviral activity. The capability to hinder herpes simplex virus type 2 replication of macrophages from healthy donors and from patients with breast cancer was compared to the in-vitro treatment with Escherichia coli lipopolysaccharide (LPS). The LPS showed a dose-dependent effect on the different macrophage populations studied. Nevertheless, macrophages from healthy donors appeared to be more sensitive to LPS in comparison with macrophages from the patients under our observation. On these cells LPS treatment was not able to modify the antiviral property, when these macrophages were differentiated in autologous serum.

Role of exogenous interferons on intrinsic antiviral activity of macrophages from patients affected by neoplasia

Macrophages derived from in vitro cultured monocytes were infected with herpes simplex virus type 2. A marked impairment in the intrinsic antiviral activity was found in macrophages obtained from patients with breast cancer or melanoma. Moreover, the antiviral activity of macrophages from healthy donors, differentiated in serum from patients with neoplasia, was also impaired. The aim of this work was the evaluation of alpha, beta, gamma exogenous interferon in restoring the intrinsic antiviral activity of macrophages from patients affected by breast cancer or melanoma under different conditions. Pretreatment of macrophages with alpha, beta interferons, but not gamma interferon, restored their impaired intrinsic antiviral activity.