Direct cell-to-cell contact with NLCs increases the expression of anti-apoptotic genes in CLL lymphocytes, thus protecting them against induced apoptosis

Direct cell-to-cell contact with NLCs increases the expression of anti-apoptotic genes in CLL lymphocytes, thus protecting them against induced apoptosis. apoptosis induced with DEX and CLB (p < 0. 001; p= 0. 012, respectively), and their protective effect was more evident than the effect of recombinant SDF1. Both DEX and CLB also decreased NLCs viability, but to a lesser extent (mean viability in DEX-treated cultures was 37. 79 % in NLCs compared to 29. 24 % in lymphocytes). NLCs MW-150 induced the expression of important anti-apoptotic genes in cultured CLL lymphocytes; median expression ofBCL2, SURVIVIN, BCL2A1, andXIAPwas significantly higher as compared to ex vivo status. The CLL lymphocyte/NLC co-culture makes up the convenient and close to the natural-state model intended for studying the relationship between leukemic cells and the microenvironment. Direct cell-to-cell contact with NLCs increases the expression of anti-apoptotic genes in CLL lymphocytes, thus protecting them against induced apoptosis. As the effect of antileukemic drugs is not so apparent in NLCs, the combined therapy targeted at both lymphocytes and the microenvironment should be considered for CLL patients. Simultaneous aiming at the disruption of several different signaling pathways and/or anti-apoptotic proteins may further improve treatment efficiency. == Electronic supplementary material == The online version of this article (doi: 10. 1007/s10238-013-0268-z) contains supplementary material, which is available to authorized users. Keywords: MW-150 CLL, Nurse-like cells, Microenvironment, Apoptosis, Gene expression profiling == Intro == B-cell chronic lymphocytic leukemia (B-CLL) is characterized by an accumulation of leukemic lymphocytes in peripheral blood, bone marrow, and lymphatic organs [1]. Increase in lymphocyte number is due both to decreased apoptosis Rabbit Polyclonal to HLAH and to slightly increased proliferation of B cells observed in proliferation centers [2]. Once isolated from circulation, leukemic cells die rapidly by apoptosis, which suggests that not only their intrinsic properties contribute to the prolonged survival. Indeed, growing evidence confirms the importance of microenvironmental signals intended for leukemic lymphocyte growth and resistance to the therapy [2]. CLL microenvironment is composed of cells of different origin, including activated T lymphocytes, dendritic cells, stromal cells, endothelial cells, and nurse-like cells (NLCs) [3]. The latter were named after thymic nurse cells, which were found to be necessary for proper maturation and differentiation of thymocytes [4]. CLL nurse-like cells were first explained by Burger et al. in 2000 [5]. They differentiate from peripheral blood monocytes of CLL patients in in vitro cultures, but were also found in vivo, within pseudo follicles present in tissue infiltrates [6]. In vitro, NLCs protect leukemic cells against spontaneous apoptosis by producing chemokines and interleukins, i. e., SDF1, IL8, CCL2, CXCL9, and by direct cell-to-cell contact [5, 79]. Recently, we characterized the gene expression pattern of NLCs and stated that they resemble tumor-associated macrophages (TAMs), which support growth of solid tumor cells and thus may influence the prognosis [9]. The discovery from the role played by microenvironment in CLL development and course resulted in intensive research in this field, mainly aimed at disrupting the pro-survival signalization pathways. Many models mimicking the interactions between CLL cells and their microenvironment were proposed for this purpose. However , the cells used to date resemble CLL environment only in some aspects [10]. Here, we developed the natural model intended for investigation, which utilizes NLCs grown from peripheral blood of CLL patients, and we compared it with non-cell model of culture supplemented with SDF1, which is MW-150 considered as the most important NLC-derived chemokine [5]. We also assessed the viability of lymphocytes cultured as such after exposure to two drugs of different mechanisms of action: dexamethasone and chlorambucil. We were the first to MW-150 evaluate the sensitivity of NLCs to these antileukemic agents. Finally, we have analyzed gene expression pattern of CLL lymphocytes cultured with NLCs with special focus on anti-apoptotic genes and compared it to ex festn status. == Methods == == Patients == With informed consent, in accordance with the Declaration of Helsinki and approval from the Medical University Bioethics Committee, peripheral blood was obtained from 35 previously untreated patients, hospitalized at the Department of Hematooncology and Bone Marrow Transplantation, Medical University of Lublin. Five patients were excluded because less than 15 NLCs/mm2was obtained in the culture. Among the leftover 30, there were 10 women and 20 men, aged 3680 years (median 68. 5), diagnosed with B-CLL according to standard criteria [11]. According to Rai classification, 5 patients were at stage 0 (16. 6 %), 5 at stage I, 18 at stage II (60 %), 1 at stage III (0. 3 %), and 1 at stage IV [12]. WBC ranged 10. 6530. 0 109/l (median 77. 7 109/l) (Table1). Detailed patients clinical data are presented in Supplementary Table S1. == Table 1 . == Summarized clinical characteristics.