IL-10 alters prolactin receptor activity emulating that during breast cancer Sonali Paul a , Amlan Biswas b,1 , Krittika Sasmal b , Subhadeep Mukherjee b , Tapas Biswas b , Ratna Biswas b, * a Department of Genetics, Vivekananda Institute of Medical Sciences, Ramakrishna Mission Seva Pratisthan, 99, Sarat Bose Road, Kolkata-700 026, West Bengal, India b Division of Immunology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Kolkata-700 010, West Bengal, India article info Article history: Received 7 December 2009 Received in revised form 31 March 2010 Accepted 25 April 2010 Keywords: Interleukin-10 Prolactin receptor Peripheral blood mononuclear cells Breast cancer abstract Peripheral blood mononuclear cells (PBMC) of breast cancer patients show altered prolactin (PRL)-induced proinflammatory response and express short form of prolactin receptor (PRL-R), besides secreting elevated level of interleukin (IL)-10 than that of the normal counterparts. IL-10 depleted the functional long form of PRL-R mRNA and protein, expressed PRL-R (SF) mRNA and blocked the PRL response found in normal individuals, which could be a mechanism to suppress the proinflammatory immune responses during malignancy. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction Prolactin (PRL), the pituitary hormone of cytokine/hemopoietin family [1] acts through PRL-receptor (PRL-R), which is expressed in diverse array of immune cells and like the classical cytokine recep- tors, signals through the JAK/STAT pathway [1,2]. Pro- and anti- inflammatory effects, at low- and high-dose of PRL on CD4 + T cells, involve modulation of T-bet, the transcription factor responsible for Th1 response and alteration in PRL-R signaling [2,3]. Besides, PRL plays a significant role in maintenance of immune homeostasis during stress, trauma or injury [4]. Malignancy is a stressful condi- tion where tumor exerts suppressive effect on immune cells through immunomodulatory cytokines [5]. In cancer patients, a shift from Th1 to Th2 immune response, increase in interleukin (IL)-10 secreting regulatory T cells and elevated level of serum IL-10 have been reported [6]. With development of tumor, thymo- cytes and peritoneal macrophages of mice and monocytes or NK cells of humans become unresponsive to PRL [7]. Binding of PRL to PRL-R as well as expression of PRL-R isoforms change in PRL- unresponsive thymocytes of tumor-bearing mice [8]. Immunosup- pressive cytokines secreted by tumors induce aberration of PRL-R and alteration in PRL-regulated immune responses of mouse thy- mocytes [9]. This paper shows that peripheral blood mononuclear cells (PBMC) of normal individuals and breast cancer patients differen- tially release IL-10 and IL-12, the cytokines that orient CD4 + T help- er cell response towards tolerance and immunity, respectively [5]. The proinflammatory role of PRL during malignancy was assessed by quantifying the release of IL-10 and IL-12, expression of antitu- mor cytokine IFN-c, chemokine IFN-inducible protein-10 (IP-10) and PRL responsive genes, interferon regulatory factor (IRF)-1 and cytokine-inducible src homology-2-containing protein (CIS) [3,10], along with the expression of varying PRL-R isoforms. IL-10 mediated PRL-induced proinflammatory response and PRL-R expression in PBMC of normal individuals were included to explain the role of the immunosuppressive cytokine in down-regulating the proinflammatory response in cancer. 2. Materials and methods 2.1. Patients Heparinised venous blood samples were collected with in- formed consent from 25 to 55 years old, untreated female breast cancer patients attending Dr. B.C. Roy Post-graduate Institute of Basic Medical Sciences, Kolkata-700 020, according to the Institu- tional Ethical Committee guidelines. All the healthy volunteers as control group were age and sex matched. 2.2. Isolation of PBMC Heparinised venous blood samples were collected from healthy women and breast cancer patients. PBMC were isolated by density centrifugation at 800g of heparinised blood layered on Ficoll-Hyp- 1043-4666/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.cyto.2010.04.012 * Corresponding author. Tel.: +91 33 2363 3854; fax: +91 33 2363 2398. E-mail address: immuneprolactin@yahoo.co.in (R. Biswas). 1 Present address: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Room 1420A, Dana Building, 44 Binney Street, Boston, MA 02115, USA. Cytokine 51 (2010) 144–150 Contents lists available at ScienceDirect Cytokine journal homepage: www.elsevier.com/locate/issn/10434666