Properties of monocytes generated from haematopoietic CD34+ stem cells from bone marrow of colon cancer patients

Monocytes exhibit direct and indirect antitumour activities and may be potentially useful for various forms of adoptive cellular immunotherapy of cancer. However, blood is a limited source of them. This study explored whether monocytes can be obtained from bone marrow haematopoietic CD34(+) stem cells of colon cancer patients, using previously described protocol of expansion and differentiation to monocytes of cord blood-derived CD34(+) haematopoietic progenitors. Data show that in two-step cultures, the yield of cells was increased approximately 200-fold, and among these cells, up to 60 % of CD14(+) monocytes were found. They consisted of two subpopulations: CD14(++)CD16(+) and CD14(+)CD16(−), at approximately 1:1 ratio, that differed in HLA-DR expression, being higher on the former. No differences in expression of costimulatory molecules were observed, as CD80 was not detected, while CD86 expression was comparable. These CD14(+) monocytes showed the ability to present recall antigens (PPD, Candida albicans) and neoantigens expressed on tumour cells and tumour-derived microvesicles (TMV) to autologous CD3(+) T cells isolated from the peripheral blood. Monocytes also efficiently presented the immunodominant HER-2/neu(369–377) peptide (KIFGSLAFL), resulting in the generation of specific cytotoxic CD8(+) T lymphocytes (CTL). The CD14(++)CD16(+) subset exhibited enhanced cytotoxicity, though nonsignificant, towards tumour cells in vitro. These observations indicate that generation of monocytes from CD34(+) stem cells of cancer patients is feasible. To our knowledge, it is the first demonstration of such approach that may open a way to obtain autologous monocytes for alternative forms of adaptive and adoptive cellular immunotherapy of cancer

Induction of reactive oxygen intermediates in human monocytes by tumour cells and their role in spontaneous monocyte cytotoxicity

The present study examined the ability of human monocytes to produce reactive oxygen intermediates after a contact with tumour cells. Monocytes generated oxygen radicals, as measured by luminol-enhanced chemiluminescence and superoxide anion production, after stimulation with the tumour, but not with untransformed, cells. The use of specific oxygen radical scavengers and inhibitors, superoxide dismutase, catalase, dimethyl sulphoxide and deferoxamine as well as the myeloperoxidase inhibitor 4-aminobenzoic acid hydrazide, indicated that chemiluminescence was dependent on the production of superoxide anion and hydroxyl radical and the presence of myeloperoxidase. The tumour cell-induced chemiluminescent response of monocytes showed different kinetics from that seen after activation of monocytes with phorbol ester. These results indicate that human monocytes can be directly stimulated by tumour cells for reactive oxygen intermediate production. Spontaneous monocyte-mediated cytotoxicity towards cancer cells was inhibited by superoxide dismutase, catalase, deferoxamine and hydrazide, implicating the role of superoxide anion, hydrogen peroxide, hydroxyl radical and hypohalite. We wish to suggest that so-called ‘spontaneous’ tumoricidal capacity of freshly isolated human monocytes may in fact be an inducible event associated with generation of reactive oxygen intermediates and perhaps other toxic mediators, resulting from a contact of monocytes with tumour cells. © 1999 Cancer Research Campaig

Isolation and functional characteristics of FcR+ and FcR- human monocyte subsets.

Abstract Human peripheral blood monocytes (M phi) were separated into Fc receptor positive (FcR+) and FcR- subsets by rosetting with O,Rh+ human erythrocytes coated with IgG anti-D antibody, followed by density gradient centrifugation and adherence. The FcR+M phi suppressed PHA- and PPD-induced lympho-proliferation and also exhibited a strong cytostatic effect against tumor cell lines in vitro, but were a poor source of antigen-presenting cells. In contrast, the FcR- subset did not cause suppression but was highly active in the presentation of PPD to T cells and in stimulation of both allogeneic mixed lymphocyte reaction (allo-MLR) and autologous (auto-MLR). PWM-induced immunoglobulin secretion in vitro was greatly enhanced by the FcR- but not the FcR+ subset. Nevertheless, both FcR+ and FcR- subsets showed comparable HLA-DR antigen expression. These results indicate that human M phi, like lymphocytes, may consist of several subsets that differ significantly in their immunologic functions.</jats:p

Colorectal cancer-derived microvesicles modulate differentiation of human monocytes to macrophages

BACKGROUND: Tumour-derived microvesicles (TMVs) are important players in tumour progression, modulating biological activity of immune cells e.g. lymphocytes, monocytes and macrophages. This phenomenon is particularly interesting in the progression of colon cancer, as macrophages in this type of tumour are relevant for the recovery processes. In the present study, the role of colon cancer cell-derived microvesicles in monocyte differentiation and activity profile (polarization) was investigated. METHODS: Monocyte-derived macrophages (MDM) were differentiated in vitro in the presence of TMVs obtained from colon cancer: Caco-2, SW620, LoVo or SW480 cell lines and analysed according to their morphology and biological functions, as defined by cytokine secretion, reactive oxygen intermediate (ROI) production and cytotoxic activity against respective colon cancer cells. RESULTS: Monocytes differentiated with TMVs exhibited morphological and phenotypical characteristics of macrophages. An early contact (beginning with the first day of the in vitro culture) of monocytes with TMVs resulted in increased IL-10 secretion and only slightly elevated TNF release. Early, or prolonged contact resulted in low ROI production and low cytotoxicity against tumour cells. On the other hand, late contact of MDM with TMVs, stimulated MDM to significant TNF and IL-12 secretion, ROI production and enhanced cytotoxicity against tumour cells in vitro. In addition, differences in MDM response to TMVs from different cell lines were observed (according to cytokine secretion, ROI production and cytotoxicity against tumour cells in vitro). Biological activity, STATs phosphorylation and microRNA profiling of MDMs indicated differences in their polarization/activation status which may suggest mixed polarization type M1/M2 with the predominance of proinflammatory cells after late contact with TMVs. CONCLUSIONS: Macrophage activity (polarization status) may be regulated by contact with not only tumour cells but also with TMVs. Their final polarization status depends on the contact time, and probably on the vesicle “cargo”, as signified by the distinct impact of TMVs which enabled the switching of MDM maturation to regulatory macrophages

The preoperative lymphocyte to monocyte ratio predicts clinical outcome in patients with stage III colon cancer

BACKGROUND: Inflammation has a critical role in the pathogenesis and progression of cancer. The lymphocyte to monocyte ratio (LMR) could be shown to be prognostic in haematologic neoplasia. In this study, we analysed the LMR with clinical outcome in stage II and III colon cancer patients. METHODS: Three hundred and seventy-two patients with stage II and III colon cancer were included in this retrospective study. Kaplan–Meier curves and multivariate Cox-regression analyses were calculated for time to recurrence (TTR) and overall survival (OS). RESULTS: Including all patients, the elevated preoperative LMR was significantly associated with increased TTR and OS in multivariate analysis (HR: 0.47, 95%CI: 0.29–0.76, P=0.002; HR: 0.51, 95%CI: 0.31–0.83, P=0.007; respectively). In subanalyses, the association was limited to patients with stage III (HR: 0.40, 95%CI: 0.22–0.72, P=0.002), in contrast to patients with stage II (HR: 0.40, 95%CI: 0.28–1.66, P=0.397). When the subgroup of patients with ‘high-risk' LMR⩽2.83 was analysed, no benefit of adjuvant 5-FU-based chemotherapy could be found (HR: 0.99; 95%CI: 0.60–1.63; P=0.953). CONCLUSION: The LMR might be an independent prognostic marker for TTR in stage III colon cancer patients. Our results further suggest that high-risk patients based on the LMR do not benefit from adjuvant chemotherapy. Independent validation of our findings is warranted