Cigarette smoke condensate promotes pro-tumourigenic stromal-epithelial interactions by suppressing miR-145.

BACKGROUND: Exposure to factors released from tobacco during chewing or smoking is recognized as a major risk factor for oral carcinogenesis and influences the phenotype of oral epithelial cells and fibroblasts within the underlying stroma. Micro(mi)RNA can regulate the expression of genes within cells, and previous studies show that tobacco products can alter the miRNA profiles in lung epithelial cells. However, the molecular alterations occurring in oral fibroblasts exposed to tobacco constituents remain to be elucidated. METHODS: Oral fibroblasts were exposed to cigarette smoke condensate (CSC) and miRNA expression compared to untreated controls using tiling low-density arrays (TLDA). Expression of miRNA-145 was confirmed by quantitative (q)RT-PCR. The effect of CSC on fibroblast cell viability, motility and matrix metalloproteinase (MMP)-2 expression was measured using MTS, a wound scratch assay and qRT-PCR, respectively. Oral cancer cell migration in response to culture supernatants from mock, control or pre-miR-145-transfected CSC-treated fibroblasts was analysed by chemotaxis assay. RESULTS: TLDA analysis identified widespread changes in the miRNA expression profile of fibroblasts exposed to CSC. Pri-, pre- and mature miRNA-145 were significantly down-regulated in response to CSC, and this was accompanied by up-regulated expression of MMP-2 and increased migration of fibroblasts compared to untreated controls. Re-expression of miR-145 abrogated the ability of fibroblasts to promote oral cancer cell chemotaxis in response to CSC. CONCLUSION: These findings suggest that tobacco constituents influence the expression of miRNA within oral fibroblasts promoting a phenotype that increases oral cancer migration and sheds new light on the mechanisms underlying oral cancer pathogenesis.

Immunohistochemical studies of human uteroplacental tissues from first-trimester spontaneous abortion.

OBJECTIVE: Atypical expression of human leukocyte antigen histocompatibility molecules or complement regulatory proteins by placental trophoblast has been hypothesized as a mechanism for spontaneous abortion. The purpose of this study was to determine expression of these proteins by placental villous trophoblast and to identify leukocyte populations within uteroplacental tissues from women with their first spontaneous abortion, their fourth or more recurrent spontaneous abortion, and from women having elective pregnancy termination. STUDY DESIGN: Fresh uteroplacental tissues were obtained at 6 to 9 weeks' gestation from eight women with their first spontaneous abortion, 20 women experiencing their fourth or more unexplained recurrent spontaneous abortion, and 20 women having an elective pregnancy termination. These tissues were analyzed immunohistochemically for human leukocyte antigen histocompatibility molecules (class I and II major histocompatibility complexes), complement regulatory proteins (CD46, CD55), and leukocyte phenotypes (CD45, CD3, CD14, CD56). RESULTS: There was absence of cell surface expression of class I and II human leukocyte antigen molecules but strong trophoblast expression of complement regulatory proteins in all villous placental samples. Leukocyte infiltration was noted in all decidual specimens. The predominant decidual leukocyte population was CD3-negative, CD56-positive cells, except in four cases of recurrent abortion where the normal ratio (< or = 2:3) of CD14-positive macrophages to CD56-positive leukocytes was > 2:1. There was an unusual retention of maternal class II major histocompatibility complex-positive leukocytes within intervillous spaces attached to the apical surface of syncytiotrophoblast from one individual with recurrent abortion. CONCLUSION: Our data do not support the hypothesis that some cases of recurrent spontaneous abortion result from atypical expression of human leukocyte antigen histocompatibility molecules or lack of complement regulatory protein expression by placental villous trophoblast. These data suggest that occasional cases of recurrent spontaneous abortion could be associated with an impaired CD56-positive leukocyte response in the early decidualized endometrium.

A murine monoclonal antibody (RV3-27) raised against isolated human placental endogenous retroviral particles and reactive with syncytiotrophoblast.

Particles with the characteristic shape of enveloped retroviral particles and maximal specific reverse transcriptase (RTase) activity at buoyant density of 1.15-1.17 g/ml have been isolated from human first-trimester chorionic villous tissue. Murine monoclonal antibodies (mAbs) to these isolated particles were generated. One IgM mAb (RV3-27) showed granular staining of cytoplasmic structures within syncytiotrophoblast by immunohistochemistry. Immunoelectron microscopic studies have demonstrated focal localisation to small submembranous regions of syncytiotrophoblast, as well as reaction with detergent-disrupted isolated placental retroviral-like particles. The RV3-27 mAb did not stain other human tissues in this focal manner, although increased generalised cytoplasmic staining was not uncommon; also, this mAb did not react strongly with the surface or cytoplasm of a variety of human cell lines (including choriocarcinoma cells). Immunoblotting and HPLC analyses have indicated the reactive placental antigen to be a 17-25 kDa protein. It is suggested that the RV3-27 mAb may be reactive with a syncytiotrophoblast antigen encoded by an endogenous retroviral sequence.

Expression of the CD46 antigen, and absence of class I MHC antigen, on the human oocyte and preimplantation blastocyst.

Expression of CD46 and class I major histocompatibility complex (MHC) antigens by human oocytes and 6-8-day unhatched expanded preimplantation blastocysts has been studied by immunocytochemistry. The CD46 antigen, a cell surface complement regulatory protein, was expressed by unfertilized oocytes as well as strongly by both the inner cell mass and trophectoderm of preimplantation blastocysts. In contrast, class I MHC antigens were not usually expressed by either oocytes or blastocysts. These data support the concept that gametes and embryonic cells involved in fertilization and early implantation events, respectively, may be protected from immunological recognition or attack both by the lack of class I MHC antigens and by expression of the CD46 complement regulatory protein.