Low expression of beta 1, alpha 2 and alpha 3 subunits of VLA integrins in malignant mammary tumours.

The Very Late Antigens (VLAs) are alpha beta heterodimeric transmembrane proteins mediating cell-substratum as well as cell-cell interactions. Changes in their expression and/or function seem to occur in a number of invasive carcinomas and may at least in part explain their abnormal patterns of growth and differentiation. Using monoclonal antibodies to the beta 1 (DH12, A1A-5), alpha 2 (B1.515) and alpha 3 (E1.56) chains, VLA-2 (alpha 2 beta 1) and VLA-3 (alpha 3 beta 1) were studied on cryostat sections of three fibroadenomas and 43 invasive breast carcinomas (29 ductal, 14 lobular) by the avidin-biotin complex immunoperoxidase technique. In non-neoplastic breast tissue and in fibroadenomas VLA-2 and VLA-3 were expressed by myoepithelial cells and on the basolateral surface of the luminal cells. There was weak or absent expression of alpha 2, alpha 3 and the common beta 1 chain in the majority of invasive carcinomas compared to the adjacent normal breast epithelium and preinvasive (in-situ) carcinomas. In addition, the expression of the alpha 2 chain of VLA-2 was reduced significantly (P less than 0.005) in the poorly differentiated ductal breast carcinomas (Grade III) compared to the well (Grade I) and moderately (Grade II) differentiated ductal tumours. These data give further evidence that loss or down-regulation of VLA-2 and VLA-3 occur relatively frequently in invasive cancers, and, at least in the invasive ductal breast carcinomas. Loss of an extracellular matrix receptor controlling growth and differentiation seems to be one of the abnormalities underlying the progression towards an undifferentiated morphology.     

Distribution of integrin cell adhesion receptors in normal and malignant lung tissue.

The integrins are a family of transmembrane glycoproteins that serve as cell-cell and cell-substratum adhesion molecules and help regulate cellular morphology, differentiation, and proliferation. The integrin repertoire of a cell may therefore influence its behavior under resting conditions or following malignant transformation. For this reason, the distribution of integrins in normal lung tissues was determined using monoclonal antibodies against integrins of the beta 1 (VLA) and beta 3 (cytoadhesin) subfamilies and compared with the distribution in a limited number of lung carcinomas. The integrin subunits that bind to collagen and laminin (alpha 1, alpha 2, alpha 3, and alpha 6) and the alpha subunit, which can pair with beta 1, beta 3, or beta 5 and promote fibronectin, fibrinogen, or vitronectin binding, were the predominant integrins expressed on the major cell types of the lung, i.e., bronchial epithelium, vascular endothelium, and smooth muscle. Strong expression of the alpha 5 beta 1 fibronectin receptor and the beta 3 subunit was restricted to the endothelium of large vessels. Integrin expression by the lung carcinoma cells was somewhat heterogeneous; however, the tumors tended to express fewer integrins than did the normal bronchial epithelium.     

Immunohistochemical localization of integrins in the normal, hyperplastic, and neoplastic breast. Correlations with their functions as receptors and cell adhesion molecules.

Integrins comprise a family of transmembrane glycoproteins that modulate cell-matrix and cell-cell relationships by acting as receptors to extracellular protein ligands, and also as direct adhesion molecules. The authors studied by immunohistochemistry the distribution of the alpha 1-6,v and the beta 1,3,4 subunits of integrins in samples of normal breast, the spectrum of fibrocystic disease (FCD), and representative benign and malignant neoplasms. Monoclonal antibodies (Mabs) specific for each subunit were applied to cryosections by the avidin-biotin-complex method; selected samples were studied by double immunofluorescence microscopy with the Mabs and a polyclonal antiserum to myosin. The authors found that the alpha 1-3,6,v and the beta 1, integrin subunits were detectable in the normal breast parenchyma; myoepithelial cells were consistently more prominently stained than the basolateral aspect of the luminal cells. This immunoprofile was retained, and in cases enhanced through the spectrum of FCD, in benign tumors and in ductal and lobular carcinomas in situ. In most infiltrating ductal carcinomas, integrin staining tended to decrease except for some cases that reacted strongly for the alpha v subunit. Several mucinous carcinomas reacted strongly for alpha 2,3,6,v and beta 4 subunits, and even more so for the alpha 5 subunit that was not found in the normal breast. Subsets of infiltrating lobular carcinomas stained convincingly for alpha 1,3,6,v and beta 1 subunits in delicate but abundant kinetopodia. Our findings indicate that in hyperplasias and in benign tumors integrin expression patterns parallel those of the normal breast, whereas in carcinomas, variations include decrease, enhancement, and emergence of certain subunits that are not in the normal repertory. Alterations of integrin expression parallel phenotypic changes in breast carcinoma cells; they also reflect their disrupted interaction with the similarly disrupted extracellular matrix. Enhancement of certain integrins in some carcinomas may reflect the selection of subpopulations with increased binding capacity which in turn may impact on their invasive and metastatic properties.     

Comparison of transferrin receptors, iron content and isoferritin profile in normal and malignant human breast cell lines

We studied the mode of iron transport and storage in a human breast cancer cell line (HT-24) in comparison with a breast epithelial cell line (HBL-100). It was found that HT-24 cells incorporated over 18 h more 59Fe as compared to HBL-100 (24 vs. 16%). Yet, the number of surface transferrin-binding sites was less in cancer cells (6.2 x 10(5)) than in epithelial cells (8 x 10(5)). Moreover, the transferrin receptors in cancer cells were less affected by iron overloading as compared with epithelial cells. Following immunoprecipitation of isoferritins with specific monoclonal antibodies (MoAbs), it was found that the quantity of de novo synthesized normal ferritin immunoprecipitated with CM-G-8 MoAb was similar in both cancer and epithelial cells. However, the amount of 59Fe incorporated into the protein was significantly higher in HBL-100 cells. In contrast, HT-24 cells synthesized a high amount of placental-like isoferritin (PLF) immunoprecipitated with CM-H-9 MoAb which was significantly higher (p less than 0.001) than in epithelial cells. This isoferritin was characterized by its low iron incorporation. It is noteworthy that the ratio of PLF to normal ferritin was 2:1 in cancer cells and 0.7:1 in epithelial cells, indicating that PLF is a major type of isoferritin synthesized by HT-24 breast cancer cells. Furthermore, a significant amount of PLF was expressed on the surface of cancer cells as compared to epithelial cells. The results of this study suggest that iron supply and distribution in breast neoplastic cells are not controlled similarly to normal cells.     

The tumor microenvironment: possible role of integrins and the extracellular matrix in tumor biological behavior of intratubular germ cell neoplasia and testicular seminomas.

In the present study, we examined the distribution of integrin subunits and extracellular matrix proteins in normal testis, intratubular germ cell neoplasia (ITGCN), and primary and metastatic seminomas. Compared to normal testis in ITGCN, Sertoli cells showed increased expression of alpha 3, alpha 6, and beta 1 integrin subunits. Malignant intratubular germ cells stained for alpha 3, alpha 6, and beta 1 integrin subunits. Progression of ITGCN to invasive seminoma was associated with loss of alpha 3 integrin subunit expression by tumor cells. Consequent to this loss, it can be speculated that the strong expression on ITGCN may be related to the noninvasive character of the lesion as is also known from other noninvasive tumors. All tumors showed a strong expression of alpha 6 and beta 1 integrin subunits. The alpha 5 integrin subunit was weakly expressed in primary seminomas in all stages. No differences were observed in integrin expression between primary and metastatic tumors. The distribution of extracellular matrix proteins was heterogeneous and revealed clear architectural differences between seminomas that may reflect different stages of tumor stroma formation. To our knowledge, the results presented in this study provide the first information on the possible role of tumor-extracellular matrix interactions in the biological behavior of ITGCN and testicular seminomas.     

白血病和正常血细胞的一些细胞因子及受体表达的比较研究

目的:研究白血病细胞和正常血细胞的细胞因子及相应受体(R)的表达及其意义。方法:采用逆转录-聚合酶链反应方法检测红白血病细胞系(HEL、K562)、髓系白血病细胞系(HL-60)、单核细胞白血病细胞系(U937)、巨核细胞白血病细胞系(DAMI、MEG-01)、T淋巴瘤细胞系(HUT78)及EB病毒感染的B细胞系(CA)和正常血细胞(CD34⁺造血干细胞、外周血单个核细胞、成熟粒细胞、巨核细胞及血小板)的多种细胞因子及受体的表达。结果:①CD34⁺造血干细胞同时表达IL-1(α、β)、IL-3、IL-6、GM-CSF、G-CSF及相应受体和干细胞因子受体(SCFR)、血小板生成素受体(MPL)基因,在成熟粒细胞仅表达IL-6、IL-6R、G-CSFR、GM-CSF,巨核细胞、血小板仅表达IL-3R、IL-6、IL-6R、MPL。而TGFβ₁、TNFα及相应受体在上述正常血细胞均有持续表达。②HEL、K562、HL-60、U937、DAMI、MEG-01、HUT78及CA可同时表达至少两种以上正调控因子及相应受体,而负调控因子TGFβ₁、TNFα及受体在上述各细胞系均有表达。结论:白血病细胞株细胞存在正性多自泌环节,白血病细胞的正、负自分泌因子失衡与白血病发病有重要关系。     

The study of different methods of cell division in two transplantable lines of normal and malignant human cells

Summary A study was made of modes of division of human cancer cells—HeLa strain—and of human amnion cells with the use of monolayer cultures in synthetic medium 199 with added calf serum. The mitotic, amitotic and nuclear gemmation coefficients were determined during the 7 days of cultivation.A prevalence of mitotic division over amitosis and nuclear gemmation was noted during the first days of cultivation of amniotic cells, and on the 4th day cultivation of HeLa cells. On the 5th day, amitosis and nuclear gemmation were the prevailing forms of multiplication in the 2 cell strains.The mitotic coefficient of the HeLa cells decreased by the 7th day; amitosis, as well as solitary and multiple budding of the nucleus proved to be the prevailing form in the 2 strains of cells.Reduction of mitotic coefficient of the amniotic cells during the same period of cultivation was not so marked, but the prevalence of amitosis and nuclear budding was largely of the same character as in the HeLa cell cultures.(Presented by Active Member AMN SSSR N. A. Kraevskii) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 58, No. 10, pp. 84–87, October, 1964     

Mechanisms of the invasion of normal and malignant cells

Different examples of invasion in normal ontogenesis and during the growth of malignant genetically altered cells are discussed. The invasive migration of single epithelial cells or cell groups may be regarded as pathological variants depending on complete or partial epithelio-mesenchymal transformation. A very special new type of epithelial cell dissemination from the monolayer was observed in our experiments with epithelial cells hyperexpressing transfected RhoA gene. In these experiments, mitotic cells were squeezed out of the contracted monolayer into a fluid medium, floated passively in this medium, and settled at the substrate forming new islands. It is important to find whether this type of dissemination not associated with active cell movements can take place in tumors in vivo.     

Genetic interactions provide evidence for the role of integrins in specifying normal olfactory behavior in Drosophila melanogaster

In a previous paper, we showed that weak hypomorphic alleles at the myospheroid (mys) locus, which encodes the beta-subunit of integrin, possess defects in olfactory behavior in both adult and larva. In this paper, we show that another olfactory gene, olfE, exhibits haploinsufficient interactions with recessive alleles at the mys locus. olfE has recently been shown to be an allele of swisscheese and is now designated as sws(olfE). Our findings suggest an interaction between the sws protein and beta-integrin in the development and/or functioning of the olfactory system. Similar interactions were also observed between sws and inflated, a gene encoding the alpha2-subunit of integrin, as well as mys and multiple edematous wing (mew), a gene coding for alpha1 subunit of integrin. This study provides evidence for the roles of different integrin subunits and the sws product in regulating normal olfactory behavior in Drosophila.     

Expression of prolactin receptors in normal, benign, and malignant breast tissue: an immunohistological study

AIMS: Prolactin plays an important role in the proliferation and differentiation of normal breast epithelium, and possibly in the development of breast carcinoma. The effects of prolactin are mediated by its receptor; thus, alteration in the expression of this receptor could be important in studying the biology of breast cancer. This investigation was aimed at comparing the expression of prolactin receptors in normal, benign, and malignant breast tissue. MATERIAL/METHODS: The expression of prolactin receptors was studied in paraffin wax embedded sections of 102 breast biopsies (93 female and nine male), using the monoclonal antibody B6.2, and the avidin-biotin immunoperoxidase technique. Six biopsies were normal, 34 had benign lesions, and 62 were malignant. RESULTS: In normal cases, prolactin receptor positivity was seen only on the luminal borders of the epithelial cells lining ducts and acini. In most benign lesions, variable degrees of luminal and cytoplasmic staining were seen. Cells showing apocrine metaplasia and florid regular ductal epithelial hyperplasia were mostly negative. In malignant cases, the staining pattern was mostly cytoplasmic and heterogeneous. Forty one of the 59 carcinomas in women showed a degree of positivity involving 10-100% of the tumour cells. A significant direct correlation was found between prolactin receptor and oestrogen receptor staining when only cases that scored more than 100/300 for the latter receptor, using the H scoring system, were considered (p = 0.0207). No correlation was found between prolactin receptors and progesterone receptors, patient's age, tumour size, tumour grade, or axillary lymph node status. CONCLUSIONS: Prolactin receptors seem to be expressed at different cellular sites in normal, benign, and malignant breast epithelial cells. The receptor is expressed in more than two thirds of female breast carcinomas, suggesting that it may play a role in the pathogenesis of the disease. The positivity is correlated with moderate and strong staining for oestrogen receptors in tissue sections, but not with other prognostic factors.     

Complement (C3) receptors on dendritic reticulum cells of normal and malignant lymphoid tissue.

The aim of this study was to investigate whether dendritic reticulum cells (DRC) in normal lymphoid tissue and in malignant non-Hodgkin's lymphomas possess receptors for the third complement component (C3 receptors). For this purpose we studied the in situ expression of C3 receptors in lymphoid tissue by staining frozen tissue sections with an antiserum specific for human C3 receptors (AC3RS), using a modified immunoperoxidase method. The results indicate that DRC of normal and malignant lymphoid tissue express large amounts of C3 receptors. Absorption experiments revealed that the C3 receptors of DRC are identical with, or at least share common antigenic sites with, the C3 receptors expressed by tonsil B cells.     

Roles of gangliosides in the surface properties of normal and malignant cells

Gangliosides are ubiquitous plasma membrane components whose structural characteristics make it possible to establish multiple interactions with the pericellular microenvironment. Several receptorial activities of gangliosides have already been recognized and the possible involvement of gangliosides in growth control, adhesion, differentiation, and immunologic recognition is at present under study. The study of the role of gangliosides in cell growth control has been approached in our laboratory by investigating whether the ganglioside changes found in SV40-transformed Balb/c3T3 cells (SV3T3 cells) revert to a normal pattern in a variant of SV3T3 cells with growth properties similar to those of normal parental cells, the concanavalin A-selected SV3T3 revertant cells. These latter cells showed the same reduction of the more complex gangliosides as found in SV3T3 cells, while their amount of II3NeuAC-LacCer (GM3) was greatly increased compared to that found in either normal or transformed 3T3 cells. In order to study the role of gangliosides in the adhesion process, we analyzed the ganglioside structure of the so-called substrate-attached material, a cell surface structure involved in the adhesion of cells to substrate, from cultures of Balb/c3T3, SV3T3, and concanavalin A-selected SV3T3 revertant cells and from cultures of a system of transformed cells with different metastatic potential: the nonmetastatic B77-3T3 and the highly metastatic AA6 cells. Compared to normal cells, all the transformed cells contained smaller quantities of gangliosides in their substrate-attached material.(ABSTRACT TRUNCATED AT 250 WORDS)     

Expression and role of integrins in adhesion of human colonic carcinoma cells to extracellular matrix components

We have examined integrin expression and function in the human colon carcinoma cell line HT29, and in clonal sublines derived from the HT29 line. These cells express several different integrin subunits including beta 1, alpha 2,3, 6 and alpha_v, but do not express the classic alpha S/beta 1 fibronectin receptor. Clonal variation in the pattern of integrin expression was quite limited. The profile of integrin expression correlates well with the adhesive behavior of HT29 cells. Thus the cells adhere well to vitronectin, laminin and type IV collagen, but not at all to fibronectin. Adhesion to collagen was completely blocked by an antibeta 1 monoclonal antibody, indicating that beta 1 integrins mediate this process. Adhesion to laminin was strongly blocked by anti-beta 1 monoclonal or anti-beta 6 monoclonal, suggesting that the alpha 6/beta 1 complex functions in attachment to laminin; this was somewhat surprising since immunoprecipitation experiments indicate that most of the alpha 6 subunit seems to be associated with the beta 4 subunit. Despite their strong adherence to laminin, collagen and vitronectin, HT29 cells are not very motile and, in response to gradients of these proteins, do not migrate nearly as well as CHO cells tested under similar conditions. Since HT29 cells can undergo an enterocyte-like differentiation in glucose-free medium, we compared integrin expression in HT29 and its subclones during the process of differentiation. There was no correlation between the state of differentiation, as assessed by expression of brush-border hydrolases, and the level of expression of any of the integrin subunits measured. Thus the pattern of integrin expression in these colonic tumor cells seems to be a characteristic of the cell line, and is not readily modified by changes in cell growth or differentiation.     

Extracellular matrix components of the mouse thymic microenvironment. III. Thymic epithelial cells express the VLA6 complex that is involved in laminin-mediated interactions with thymocytes

We describe herein the expression of the VLA6 complex by murinethymic epithelial cells (TEC). The immunohistochemical distributionrevealed that VLA6 is found in both thymic medullary and subcapsullaryareas. Moreover, studies by immunoelectron microscopy revealeda membrane labeling of the VLA6 molecule, including at desmosomalsites. By means of immunoblottlng, immunoprecipitation, andaffinity chromatography of extracts from a mouse TEC line, wefurther demonstrated that VLA6 is a laminin (LN) receptor inthese cells. In keeping with this finding, we showed that TECadhesion, spreading, and proliferation were enhanced in vitroby LN. The fact that VLA6 is also expressed by the large majorityof thymocytes raised the hypothesis that it might be involvedin LN-mediated TEC—thymocyte interactions. Interestingly,in vitro experiments showed that there is an increase in theTEC—thymocyte adhesion upon glucocorticold hormone treatment,a situation in which the expression of VLA6 as well as LN isenhanced. Most importantly, this adhesion can be reversed bypre-treating TEC with an anti-6 integrin mAb. Additionally,spontaneous in vitro thymocyte release by thymic nurse cellcomplexes was enhanced by LN and partially blocked by anti-6or anti-ß1 antibodies. Our results suggest that VLA6is involved in LN-mediated TEC—thymocyte interactionsthat can be relevant for thymic microenvironmental cell physiologyand intrathymic T cell differentiation events.