Epidermal growth factor receptor and c-erbB-2 expression in normal breast tissue during the menstrual cycle

Summary EGF receptor (EGF-R) and c-erbB-2 are homologous tyrosine kinase transmembrane receptors. They are involved in controlling proliferation, and probably differentiation, of normal breast epithelial cells, and their expression has been linked to the prognosis of breast cancer. Their physiological roles in normal breast tissue remain to be elucidated, as most studies to date have involved breast cancer cell lines. We studied the location of EGF-R and c-erbB-2 in 100 samples of normal breast with standard immunohistochemical methods and double-labelling techniques. EGF-R was mainly expressed on the stroma and myoepithelial cells, whereas c-erbB-2 expression was exclusively epithelial. An image analyser was used to quantitate variations in their expression during the mentrual cycle. EGF-R and c-erbB-2 expression on epithelial cells was stronger during the luteal phase than the follicular phase (p < 0.01 for EGF-R). The pattern of expression was also compared with that in 28 breast cancers and 7 fibroadenomas.     

EGF、EGF－R在卵巢浆液性良、恶性及交界性肿瘤中的表达

应用免疫组织化学ＡＢＣ方法，检测５２例卵巢浆液性良、恶性及交界性肿瘤中ＥＧＦ、ＥＧＦ－Ｒ的表达。结果显示：ＥＧＦ、ＥＧＦ－Ｒ在卵巢浆液性囊腺瘤中分别为５０％、３７％，交界性病变中分别为６２．５％、１００％。其中ＥＧＦ－Ｒ检测良恶性及交界性病变阳性表达率有显著性差异，Ｐ＜０．０５，提示ＥＧＦ、ＥＧＦ－Ｒ在卵巢发生发展中起不同调节作用，有利于病理的诊断和临床估计预后。     

Effect of a cytotoxic analog of LH-RH (T-98) on the growth of estrogendependent MXT mouse mammary cancers: Correlations between growth characteristics and EGF receptor content of tumors

Summary Female BDF mice bearing estrogen-dependent MXT mouse mammary cancers were treated for 4 weeks with a cytotoxic analog of luteinizing hormone-releasing hormone (LH-RH), T-98 (agonist [D-Lys⁶]LH-RH linked to glutaryl-2(hydroxymethyl)anthraquinone). The effects of T-98 were compared to those of equimolar amounts of the cytotoxic moiety 2-(hydroxymethyl)anthraquinone hemiglutarate (G-HMAQ) and carrier LH-RH agonist [D-Lys⁶]LH-RH. Both T-98 and [D-Lys⁶]LH-RH significantly inhibited the growth of MXT cancers, but G-HMAQ had only a minor non-significant effect. Cytotoxic analog T-98 and the carrier [D-Lys⁶]LH-RH had similar inhibitory hormonal activities on the pituitary-gonadal axis, but T-98 caused a larger reduction in tumor volume and decreased proliferation characteristics such as mitotic activity and AgNOR numbers in tumor cells to a greater extent than the carrier. Tumor inhibition by T-98, [D-Lys⁶]LH-RH, and ovariectomy was connected with a significant decrease in binding capacity of EGF receptors in tumor cell membranes. The concentration of EGF receptors remained high in tumors that continued to enlarge in spite of treatment and in all control untreated tumors, even those of small size. Thus, the changes in EGF receptors are likely to be the result of the therapy. Treatment with T-98 caused a greater reduction in the binding capacity of EGF receptors in tumors than [D-Lys⁶]LH-RH. This could explain the higher inhibitory effect of the cytotoxic analog on tumor growth. Since radiolabeled T-98 was shown to accumulate in MXT cancers 3 hours after a subcutaneous injection, this indicates that specific targeting might play a role in the antitumor effect exerted by this cytotoxic analog.Abbreviations LH luteinizing hormone - LH-RH LH-releasing hormone - EGF epidermal growth factor - EGF-R EGF receptor - TGF transforming growth factor - NOR nucleolar organizing region - AgNOR argyrophilic NOR - G-HMAQ 2(hydroxymethyl)anthraquinone-hemiglutarate - HPLC high performance liquid chromatography - TNF tumor necrosis factor - 5-FU 5-fluorouracil - PBS phosphate-buffered saline     

Melatonin and prostate cancer cell proliferation: interplay with castration,epidermal growth factor,and androgen sensitivity

BACKGROUND: Potential modulatory effects of melatonin on the proliferation of androgen-sensitive LNCaP and androgen-insensitive PC-3 and DU 145 prostate cancer cells were reported recently. In this study, we investigated the effects of combined melatonin and castration on LNCaP tumor growth in vivo, the interactions between melatonin and epidermal growth factor (EGF) on LNCaP cell proliferation, and melatonin actions on the proliferation of PC-3 and DU 145 cells. METHODS: Tumor development and growth in castrated nude mice inoculated with LNCaP cells or in intact animals inoculated with DU 145 cells, with or without daily melatonin treatment, were monitored by observation and caliper measurement. MT(1) receptor expression in native or transfected prostate cancer cell lines was examined by immunocytochemistry or 2-[(125)I]iodomelatonin binding. Cyclin D1 expression in LNCaP cells was assessed by Western blotting, and cell proliferation was measured by thymidine incorporation and/or cell count. RESULTS: Melatonin treatment was associated with further decreases in LNCaP tumor incidence and growth rate in castrated nude mice. Melatonin and 2-iodomelatonin (a melatonin receptor agonist) attenuated EGF-stimulated increases in LNCaP cell proliferation and cyclin D1 levels. Melatonin had no effect on the proliferation or growth of MT(1) receptor-expressing DU 145 cells, and of PC-3 cells in which MT(1) receptor protein was undetectable. The proliferation of transfected PC-3 cells expressing MT(1) receptor was unaffected by 2-iodomelatonin. CONCLUSION: Together with previous data, the present results indicate synergistic action of melatonin and castration in inhibiting the growth of androgen-sensitive LNCaP tumor. Androgen-sensitive prostate cancer cell proliferation may be modulated by opposite changes in cyclin D1 levels induced by activated MT(1) and EGF receptors. In androgen-insensitive prostate cancer cells, MT(1) receptor-mediated signal transduction may become defective not only through changes in membrane receptor protein expression and/or functions, but also by means of alterations in downstream postreceptor signaling events.     

Pterygial derived fibroblasts express functionally active histamine and epidermal growth factor receptors

Pterygia are characterised by a fleshy outgrowth of altered conjunctival tissue over the cornea and are most common in tropical regions. Pterygial fibroblasts are characteristically distinct from normal conjunctival fibroblasts, and therefore the aim of this study was to determine the presence and functional significance of histamine and epidermal growth factor (EGF) receptors in these cells. Pterygial specimens were cultured in vitro and cellular outgrowths were phenotypically characterised as fibroblasts using vimentin and cytokeratin staining. Intracellular calcium mobilization was used to characterise the functional activity of histamine receptors on these cells. Maximal response was obtained with 100 microM histamine. However, lower concentrations of histamine also caused mobilization of calcium that were totally abolished by pre-incubation with H1 but not H2 or H3 receptor antagonists. EGF receptor was diffusely expressed over the cell surfaces. EGF stimulated receptor internalization, ERK protein phosphorylation and intracellular calcium mobilization. Therefore, fibroblasts derived from human pterygia express functionally active histamine and epidermal growth factor receptors. Controlled modification of either the receptors or the appropriate ligands could have beneficial effects in pterygia treatment.     

Cancer chemoprevention by tea polyphenols through modulating signal transduction pathways

The action mechanisms of several chemopreventive agents derived from herbal medicine and edible plants have become attractive issues in cancer research. Tea is the most widely consumed beverage worldwide. Recently, the cancer chemopreventive actions of tea have been intensively investigated. It have been demonstrated that the active principles of tea were attributed to their tea polyphenols. Recently, tremendous progress has been made in elucidating the molecular mechanisms of cancer chemoprevention by tea and tea polyphenols. The suppression of various tumor biomarkers including growth factor receptor tyrosine kinases, cytokine receptor kinases, PI3K, phosphatases, ras, raf, MAPK cascades, N x FB, I x B kinase, PKA, PKB, PKC, c-jun, c-fos, c-myc, cdks, cyclins, and related transducing proteins by tea polyphenols has been studied in our laboratory and others. The I x B kinase (IKK) activity in LPS-activated murine macrophages (RAW 264.7 cells) was found to be inhibited by various tea polyphenols including (-) epigallocatechin-3-gallate (EGCG), theaflavin (TF-1), theaflavin-3-gallate (TF-2) and theaflavin-3,3'-digallate (TF-3). TF-3 inhibited IKK activity in activated macrophages more strongly than did the other tea polyphenols. TF-3 inhibited both IKK1 and IKK2 activity and prevented the degradation of I x B x and I x B x in activated macrophage cells. The results suggested that the inhibition of IKK activity by TF-3 and other tea polyphenols could occur by a direct effect on IKKs or on upstream events in the signal transduction pathway. TF-3 and other tea polyphenols blocked phosphorylation of IB from the cytosolic fraction, inhibited NFB activity and inhibited increases in inducible nitric oxide synthase levels in activated macrophage. TF-3 and other tea polyphenols also inhibited strongly the activities of xanthine oxidase, cyclooxygenase, EGF-receptor tyrosine kinase and protein kinase C. These results suggest that TF-3 and other tea polyphenols may exert their cancer chemoprevention through suppressing tumor promotion and inflammation by blocking signal transduction. The mechanisms of this inhibition may be due to the blockade of the mitogenic and differentiating signals through modulating EGFR function, MAPK cascades, NFkappaB activation as well as c-myc, c-jun and c-fos expression.     

Neuronal and glial differentiation within expanded glial cultures derived from the lateral and medial ganglionic eminences

Attached glial-like cell cultures were established from the lateral and medial ganglionic eminences (LGE and MGE) and from the neocortex (Cx) of E13.5 mouse embryos, and expanded over four to five passages under epidermal growth factor (EGF) stimulation. Following removal of EGF and serum, we analysed the generation of neurons and glial cells within the cultures. Significant numbers of betaIII-tubulin-positive neurons were generated in both the LGE (about 7% of total cell numbers) and the MGE (around 2%). However, only few betaIII-tubulin-positive cells with neuronal morphologies were detected in the differentiated Cx cultures. The newly formed neurons were to a large extent GABAergic, and many of the MGE-derived, but not the LGE-derived, cells expressed the MGE-marker NKX2.1. Most cells in all cultures still appeared astroglial-like, expressing glial fibrillary acidic protein (GFAP), but in addition, CNPase-positive cells with oligodendroglial morphologies were present in the MGE (0.68%), and, to a lesser extent (0.2%), in the LGE cultures. The present results demonstrate that cells of expanded glial cultures from both the LGE and MGE can give rise to significant and, to a certain extent, region-specific neuronal and glial cell types under differentiating conditions.     

大鼠骨髓间充质干细胞分化为肝样细胞的实验研究

目的探讨大鼠骨髓间充质干细胞(MSCs)体外诱导分化为肝样细胞的能力。方法利用密度梯度离心法分离、纯化培养大鼠骨髓间充质干细胞,在特定的培养液中加入肝细胞生长因子(HGF)和表皮细胞生长因子(EGF)联合培养进行定向诱导,分别于1周和2周后通过逆转录-聚合酶链反应(RT-PCR)鉴定经诱导后细胞甲胎蛋白(AFP)和白蛋白(ALB)的表达。结果诱导1周后RT-PCR检测MSCs示AFP表达,诱导2周后的MSCs AFP呈阴性,而ALB检测结果呈阳性。结论MSCs在体外特定的条件下可定向诱导分化为肝样细胞。     

EGF,bFGF单独及联合应用对原代培养的兔角膜缘干细胞增殖的影响

目的探讨EGF,bFGF及二者共同作用对培养的兔角膜缘干细胞增殖的影响。方法用DMEM和F12(1:1)培养基,20%胎牛血清,加入不同浓度EGF,bFGF和二者的混合液,采用MTT法检测细胞的OD值。结果EGF的5~160ng/mL各浓度组增殖效应均明显大于对照组(P<0.05),10ng/mL组明显大于其它各浓度组(P<0.01),bFGF各浓度组从5~80ng/mL各组均明显大于对照组(P<0.025),20ng/mL各组明显大于与其它各组(P<0.025);EGF与bFGF混合液各浓度组从5~80ng/mL各组增殖效应均明显大于对照组及单独使用EGF或bFGF组(P<0.05),EGF10ng/mL+bFGF20ng/mL组促增殖效果最强(P<0.025)。结论EGF,bFGF对培养的兔角膜缘干细胞有促增殖作用,此作用均呈剂量依赖性,EGF和bFGF共同表现为明显的促增殖作用。     

表皮生长因子与肿瘤坏死因子在胸腔积液中的表达

采用ＲＩＡ法对５８例良、恶性胸腔积液中ＥＧＦ与ＴＮＦ进行含量检测。结果显示２２例良性胸水中ＥＧＦ与ＴＮＦ含量分别为２．０３±０．３５μｇ／Ｌ，１．６３±０．５４μｇ／Ｌ。３６例恶性胸水中ＥＧＦ与ＴＮＦ含量分别为１．２５±０．３２μｇ／Ｌ，１．０２±０．２４μｇ／Ｌ。良性胸水组ＥＧＦ与ＴＮＦ浓度均明显高于恶性胸水组，两组间有显著性差异，（Ｐ＜０．０５）。结果表明ＥＧＦ与ＴＮＦ均参与了良、恶性胸腔积液的免疫病理生理过程。