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Biomedical subjects

M E Lippman

Publications and source records attributed to M E Lippman.

At least 127 records · Page 7Linked to original sources
PubMed1990

Characterization of mammary-derived growth factor 1 receptors and response in human mammary epithelial cell lines.

Mammary-derived growth factor 1 (MDGF1, with a molecular mass of 62 kDa and pI of 4.8) has been purified from human milk (Bano, M., Salomon, D. S., and Kidwell, W. R. (1985) J. Biol. Chem. 260, 5745-5752). N-terminal sequence of 18 amino acids showed no homology to any known growth promoting peptides. The present study was carried out to evaluate the biological effects of and binding sites for MDGF1 on normal human and breast cancer cell lines. At a concentration of 10-25 ng/ml the factor stimulated the growth of estrogen receptor-positive MCF-7 human breast cancer cells by 50% and also stimulated the synthesis of collagen IV by 40%. It did not have any effect on ZR75-1, T47-D, and MDA-MB 231 cells. The factor showed a biphasic effect on the estrogen receptor-negative MDA-MB 468 cells at concentrations above 5 ng/ml. The growth of normal human mammary epithelial cells (184 strain) was enhanced by 35%, whereas immortalized non-tumorigenic 184A1N4 human mammary epithelial cells were stimulated by about 60-70%. However, transformation of these cells by SV40-T, v-Ha-ras, or v-mos desensitized them to MDGF1. Iodinated MDGF1 binds to moderate affinity sites on the responsive MCF-7, MDA-MB 468, and 184A1N4 cell lines (KD = 6 x 10(-9) M). Cross-linking of 125I-MDGF1 to binding sites revealed the presence of a major band of molecular mass of approximately 180-200 kDa in MCF-7 and MDA-MB 468 cell lines. Labeling of this band was inhibited by excess unlabeled MDGF1. These data suggest that human mammary epithelial cell lines possess receptors for MDGF1.

Binding, Competitive↗
PubMed1990

Insulin-like growth factor receptor expression and function in human breast cancer.

The insulin-like growth factors IGF-I and IGF-II are potent mitogens for several breast tumor cell lines in culture. Additionally, both IGF-I and IGF-II mRNAs are easily detected in the majority of breast tumor specimens examined, while no breast cancer epithelial cell lines we have studied express authentic IGF-I mRNA, and few lines express IGF-II mRNA. Although receptors for insulin, IGF-I, and IGF-II have been described, there is significant cross-reactivity between the various receptors and ligands in the insulin/insulin-like growth factor family, and it is not clear which receptor or receptors are responsible for the biological effects of these growth factors in this system. Using an RNase protection assay, we examined breast tumor specimens and breast cancer epithelial cell lines for expression of mRNA encoding the type I and type II IGF receptors as well as the insulin receptor. Virtually all of the specimens examined expressed mRNA for all three receptors. We then examined estrogen-dependent MCF-7 cells for the mitogenic effects of IGF-I and II in the presence of antibodies to both the type I and type II receptors. alpha IR-3, a monoclonal antibody which blocks the type I receptor, abolished the mitogenic effects of both IGF-I and IGF-II. It did not, however, block the mitogenic effects of insulin. We conclude that type I and type II IGF receptors are ubiquitously expressed in breast cancer, and our experiments with MCF-7 cells suggest the mitogenic effects of both IGF-I and IGF-II are mediated via the type I IGF receptor.

Blotting, Northern↗
PubMed1990

Stromal influences on transformation of human mammary epithelial cells overexpressing c-myc and SV40T.

The proto-oncogene c-myc and the oncogene SV40T, both of which have been implicated in the process of cellular immortalization in vitro, have been introduced via amphotropic retroviral expression vectors into the human mammary epithelial cell (HMEC) line 184A1N4 (A1N4). Two stable cell lines were established by growth in selective medium and were found to overexpress either c-myc (A1N4-myc) or SV40T antigen (A1N4-T). Neither the A1N4, A1N4-myc, or A1N4-T cells will grow in soft agar or form tumors in nude mice. However, A1N4-T or A1N4-myc cells, but not the parental A1N4 cells, form colonies in soft agar in response to either epidermal growth factor (EGF), transforming growth factor alpha (TGF alpha), or basic fibroblast growth factor (bFGF). Like EGF and TGF alpha, bFGF is moderately mitogenic for the anchorage-dependent growth (ADG) of all three cell lines. Further, co-cultivation of A1N4-T or A1N4-myc cells with primary diploid mammary fibroblasts can also induce the anchorage-independent growth (AIG) and stimulate the ADG of A1N4-T or A1N4-myc. In addition, conditioned medium obtained from these mammary fibroblasts also stimulated the AIG of the A1N4-T and A1N4-myc cells and was found to contain immunoreactive TGF alpha and bioactive FGF. The mammary fibroblasts express specific mRNA transcripts for bFGF and acidic FGF (aFGF). These results suggest that growth factors such as TFG alpha or FGF, which may be derived from the adjacent mammary stroma, might influence in a paracrine manner the phenotypic characteristics of a population of human mammary epithelial cells toward transformation.

Agar↗
PubMed1990

The effects of hormonal and chemotherapy on tumoral and nonneoplastic breast tissue.

One hundred four sequential pretherapy and posttherapy breast tissue specimens from 57 patients with locally advanced and metastatic breast cancer were evaluated in an attempt to define the effects of systemic chemotherapeutic agents on the tumors and residual nonneoplastic breast tissue. The patients were treated uniformly at the National Cancer Institute on an experimental protocol combining systemic chemotherapy with attempted hormonal synchronization. Tumors were sampled prior to and following several cycles of chemotherapy to a maximum objective clinical response (average number of cycles, 7). In 38 cases, the posttreatment biopsy was positive for tumor. The most striking histologic change was extreme vacuolization of tumor cells that often resembled histiocytes. Atrophy of the terminal duct lobular unit (TDLU) and atypia of epithelial cells in TDLU and large ducts were also seen. Severe degrees of epithelial atypia occasionally proved to be difficult to distinguish from residual intraductal carcinoma. Breast biopsies were stained with antibodies to cytokeratin, epithelial membrane antigen (EMA), B72.3, lactalbumin, and SP1 using immunoperoxidase techniques. The number of cases showing immunoreactivity with antibodies to cytokeratin, EMA, and B72.3 remained approximately the same before and after therapy, while SP1 expression decreased and lactalbumin expression increased after therapy. Recognition of chemotherapeutic changes in breast tissue is important since systemic chemotherapy plays an important role in the management of breast cancer.

Adenocarcinoma, Mucinous↗
PubMed1990

Effects of TGF beta on normal and malignant mammary epithelium.

The goal of our research was to determine the effects of TGF beta on differentiation and growth of normal and malignant breast epithelial cells. The influence of TGF beta on differentiation was studied in a series of normal, immortalized, and oncogene-transformed human mammary epithelial cells. The expression of human milk fat globule antigen as differentiation marker was increased ten- to fifteenfold in normal cells and two to threefold in transformed cells after treatment with 200 pM TGF beta for 30 h. All cell lines except one were growth inhibited by TGF beta. Using the estrogen receptor-positive breast cancer cell lines MCF7, ZR-75-1, T-47D, and the estrogen receptor-negative lines MDA-MB-231, SK-BR-3, Hs578T, MDA-MB-468, we found that all tested cell lines except late passage (greater than 500) MCF7 cells were growth inhibited by TGF beta 1 as well as TGF beta 2. The maximal inhibition was 50% in estrogen receptor-positive and 80% in estrogen receptor-negative cell lines at concentrations of 800 and 40 pM, respectively in an anchorage-independent growth assay. All tested breast cancer cell lines secreted a TGF beta-like activity, the production of which was stimulated in MCF7 cells treated with antiestrogens and which inhibited the anchorage-independent growth of MDA-MB-231 cells. These observations suggest that the malignant phenotype in breast cancer need not be coupled with resistance to effects of TGF beta on growth and differentiation. Breast cancer cells being resistant to treatment with antiestrogens are still growth inhibited by TGF beta in vitro. This may partially explain the growth inhibitory effects of antiestrogens in mixtures of estrogen receptor-positive and -negative tumor cell populations in vivo.

Animals↗
PubMed1990

Pathologic findings from the National Surgical Adjuvant Breast and Bowel Project: prognostic significance of erbB-2 protein overexpression in primary breast cancer.

In order to investigate the prognostic significance of erbB-2 overexpression, immunohistochemical staining for the erbB-2 protein was performed on sections from paraffin blocks of 292 primary invasive breast cancers obtained from women enrolled in the National Surgical Adjuvant Breast and Bowel Project (NSABP) protocol B-06. Positive reaction indicative of erbB-2 overexpression was observed on tumor cells in 62 (21%) samples. Women whose cancers were judged to have erbB-2 overexpression had a significantly worse overall survival (P = .0012) with twice the mortality rate of women without detectable erbB-2 expression. No statistically significant effect was evident for disease-free survival (P = .22). In multivariate analysis, detection of erbB-2 overexpression was the second most predictive independent variable for survival after nodal status. Overexpression of erbB-2 was more common among tumors of poor nuclear grade (29%) than those of good nuclear grade (12%). The association of erbB-2 overexpression with decreased survival was evident only among women with tumors of good nuclear grade. In this subgroup, erbB-2 overexpression was associated with an approximately fivefold increase in mortality rate (P = .00001). The combined predictive value of erbB-2 overexpression and nuclear grade was evident regardless of their lymph node status. These results provide evidence that detection of erbB-2 overexpression may be an independent prognostic variable for patient survival. Moreover, when combined with evaluation of nuclear grade, it may be possible to use immunostaining for erbB-2 protein to identify patients at increased risk from within a relatively low-risk group.

Antibodies, Monoclonal↗
PubMed1990

Expression of the transforming growth factor-alpha/epidermal growth factor receptor pathway in normal human breast epithelial cells.

To better understand the possible roles and interactions of transforming growth factor-alpha (TGF alpha) and its receptor, the epidermal growth factor (EGF) receptor in human breast epithelium, we have studied the expression of TGF alpha and the EGF receptor in a series of normal human mammary epithelial cells derived from reduction mammoplasty before in vitro propagation, during short term proliferation in vitro, and after immortalization. Increased TGF alpha mRNA expression coincided with conversion of the cells to a proliferative state in vitro. After establishment, propagation, and proliferation in vitro, the cells expressed high levels of both TGF alpha and EGF receptor mRNAs. Addition of diverse growth inhibitory agents, including 12-O-tetradecanoylphorbol-13-acetate (TPA), TGF beta, and sodium butyrate, to one of these rapidly proliferating cell populations (no. 184) failed to reduce the expression of either TGF alpha or the EGF receptor. Likewise, cessation of growth associated with both senescence and confluence of the 184 cells did not result in reduced expression. However, regulation of TGF alpha mRNA could be demonstrated by withdrawal of EGF from the medium or by antibody-mediated blockade of the EGF receptor in 184 cells. Antibody-mediated EGF receptor blockade also results in inhibition of growth and [3H]thymidine labeling. An autoregulatory autocrine loop appears operant in proliferating breast epithelial cells. Both growth and levels of TGF alpha mRNA expression are controlled by binding of ligand to the EGF receptor. These studies suggest a role for the TGF alpha/EGF receptor pathway in normal breast cell physiology.

Breast↗
PubMed1990

Transforming growth factor-beta induces platelet-derived growth factor (PDGF) messenger RNA and PDGF secretion while inhibiting growth in normal human mammary epithelial cells.

Platelet-derived growth factor (PDGF) is a potent mitogen in human serum which specifically stimulates the proliferation of mesenchymal cells. We have now examined normal human mammary epithelial cells (HMEC) derived from reduction mammaplasties and grown in a serum-free defined medium. Medium conditioned by HMEC contained a PDGF-like activity that competed with [125I]PDGF for binding to PDGF receptors in normal human fibroblasts. When conditioned media were incubated with antiserum specific for either PDGF-A or PDGF-B, only PDGF-A antiserum was capable of inhibiting binding of conditioned media to PDGF receptors. Using an RNase protection assay, mRNA from normal HMEC was probed for both the PDGF-A and PDGF-B chains. Little or no PDGF-B was found in HMEC strains, while a strong signal was seen with the PDGF-A probe. When HMEC were grown in the presence of transforming growth factor-beta (TGF beta) for 48 h, inhibition of growth was observed in association with a 20- to 40-fold stimulation of PDGF-B mRNA and a 2-fold stimulation of PDGF-A mRNA. This mRNA induction was extremely rapid (within 1 h), and secreted PDGF activity was induced 2- to 3-fold. Two other HMEC growth inhibitors and differentiating agents, sodium butyrate and phorbol ester 12-O-tetradecanoylphorbol-13-acetate, had no effect on PDGF mRNA regulation. The current study suggests that PDGF gene induction is an extremely rapid and specific indicator of TGF beta function regardless of whether TGF beta is acting in a growth stimulatory or inhibitory manner. Any role of PDGF-B in TGF beta modulation of differentiation of normal or malignant mammary gland remains to be determined.

Breast↗
PubMed1990

Autocrine growth stimulation by secreted Kaposi fibroblast growth factor but not by endogenous basic fibroblast growth factor.

We studied the different potentials of a secreted and a nonsecreted member of the fibroblast growth factor (FGF) family to induce autocrine growth stimulation in human adrenal cortex carcinoma cells (SW-13). These epithelial cells express basic FGF (bFGF) cell surface receptors, and picomolar concentrations of bFGF suffice to induce anchorage-independent growth. The requirement for exogenously added bFGF contrasts with the intracellular storage of biologically active bFGF in SW-13 cells greater than 10,000-fold in excess of the concentration needed to stimulate anchorage independent growth. To study whether the expression of a secreted FGF would alter the growth phenotype of these cells, we transfected them with an expression vector coding for the Kaposi-fgf (K-fgf) oncogene. In contrast to controls, K-fgf-transfected cells secrete significant amounts of biologically active K-fgf protein into the growth media, show up to 50-fold increased colony formation in soft agar, and grow into rapidly progressing, highly vascularized tumors in athymic nude mice. A reversible inhibition of the autocrine growth stimulation in vitro is brought about by the polyanionic compound suramin. We conclude that FGF has to be released from SW-13 cells to function fully as a growth stimulator in vitro and in vivo.

Adenocarcinoma↗
PubMed1990

Effect of preoperative chemotherapy on mastectomy for locally advanced breast cancer.

Mastectomy is frequently performed after intensive chemotherapy for locally advanced breast cancer. The effects of preoperative chemotherapy on the postoperative course and the timing of subsequent adjuvant therapy, however, have not been defined. We therefore reviewed the perioperative course of 54 patients undergoing mastectomy after combination (CAMFPT) chemotherapy for stage IIIA,B (IIIA - 25 pts; IIIB noninflammatory - 5 pts; IIIB inflammatory-24 patients) breast cancer. A median of 7 cycles (6 months) of chemotherapy was administered preoperatively. Mastectomy was performed a median of 20 days after last chemotherapy; white blood cell count (WBC) and platelet counts returned to normal limits preoperatively. Total mastectomy with or without axillary node dissection was performed in 53 patients, and a Halsted radical mastectomy in 1 patient. Negative margins on breast and/or axillary tissue were achieved in 47 patients (87.0%). Postoperative complications included skin flap necrosis in 8 patients (14.8%), seroma formation in 5 patients (9.3%), and wound infection in 1 patient (1.9%). Median operative blood loss (550 cc), hospital stay (8 days), and duration of wound catheter drainage (6 days) were comparable to published reports for modified radical mastectomy without preoperative chemotherapy. Systemic chemotherapy was resumed a median of 16 days after mastectomy, and radiotherapy started a median of 33 days after mastectomy. These findings indicate that intensive preoperative chemotherapy does not increase the hospital course or the postoperative complications of mastectomy for locally advanced breast cancer. In view of the current interest in treatment of stage I and II breast cancer with preoperative chemotherapy, this information may be useful in their management as well.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

ICI 164,384, a pure antagonist of estrogen-stimulated MCF-7 cell proliferation and invasiveness.

Estrogen is known to stimulate the proliferation and basement membrane invasiveness of the MCF-7 human breast cancer cell line. We have compared the new steroidal antiestrogen ICI 164,384, the triphenylethylene 4-hydroxytamoxifen (OHT), and the benzothiophene LY 117018, for their effects on the proliferation and invasiveness of the MCF-7 cell line and its antiestrogen-resistant variant LY-2. While all three antiestrogens blocked the proliferative effects of 17 beta-estradiol on MCF-7 cells, OHT and LY 117018, but not ICI 164,384 stimulated their proliferation in the absence of estrogen. The proliferative effects of OHT and LY 117018 were blocked by ICI 164,384. Basement membrane invasiveness of MCF-7 cells was stimulated by 17 beta-estradiol and OHT, but not LY 117018 or ICI 164,384. Both ICI 164,384 and LY 117018 were able to block the invasiveness induced by either 17 beta-estradiol or OHT. The LY-2 antiestrogen-resistant variant of the MCF-7 cell line showed increased basal proliferation, and responded only slightly to estrogen. ICI 164,384, but not OHT or LY 117018 antagonized the effects of 17 beta-estradiol, but did not reduce proliferation below control levels. The LY-2 line was not resistant to the antiestrogenic effects of LY 117018 or ICI 164,384 on invasiveness, and was stimulated by LY 117018 for this parameter. Thus, ICI 164,384 is a pure antiestrogen for MCF-7 cell proliferation and invasiveness, and may offer clinical advantage over nonsteroidal antiestrogens which can stimulate these activities in tumor models in vitro.

Basement Membrane↗
PubMed1989

Production of and responsiveness to transforming growth factor-beta in normal and oncogene-transformed human mammary epithelial cells.

Transforming growth factors-beta (TGF beta) are a family of closely related, ubiquitously expressed growth factors with the common properties of induction of growth inhibition and expression of differentiation-related markers in epithelial cells. We investigated the role of TGF beta 1 in growth regulation of normal human mammary epithelial cells and in benzo(a)pyrene immortalized sublines further transformed by oncogenes in retroviral vectors. The normal cells were markedly growth inhibited by TGF beta 1, produced TGF beta in a latent form, and expressed TGF beta receptors. In the immortalized cells, both TGF beta-induced growth inhibition and TGF beta receptor binding were reduced. With the single oncogenes v-Ha-ras, v-mos, and SV40 T, growth sensitivity to TGF beta 1 increased, but TGF beta production or TGF beta receptor expression was not altered. Transformation to full malignancy by both SV40 T and v-Ha-ras led to escape from growth inhibition by TGF beta under anchorage-independent, but not anchorage-dependent, conditions without affecting TGF beta production or receptor characteristics. Thus, modulation of TGF beta growth responsiveness in these normal and oncogene transformed human mammary epithelial cells apparently occurs at a level distal to TGF beta receptor binding and is not solely correlated to expression of transforming oncogenes. Further, modulation of TGF beta production is not an indicator of malignant transformation in this system.

Benzo(a)pyrene↗
PubMed1989

Stimulation of epithelial membrane antigen expression by transforming growth factor-beta in normal and oncogene-transformed human mammary epithelial cells.

Transforming growth factor-beta (TGF beta) appears to play a role in regulating the expression of tissue-specific proteins in human mammary epithelial cells (HMEC), regardless of the state of malignant transformation. We demonstrated this by utilizing a series of normal, immortalized, and oncogene-transformed (SV40 T and v-Ha-ras) HMEC derived from one individual, and assaying for expression of a milk fat globule/epithelial membrane antigen (EMA) reactive with E29/EP1 monoclonal antibody. EMA was increased by TGF beta in all HMEC examined. This effect appeared to be dose-dependent between 5 and 15 ng/ml in the normal, immortalized, and v-Ha-ras-transformed cells but saturated at 5 ng/ml in the SV40 T-transformed cells. The SV40 T-transformed cells showed both enhanced basal expression of EMA and increased sensitivity to TGF beta stimulation of EMA expression. The degree of increase in EMA induced by TGF beta was proportional to the level of basal expression in each cell type and appeared to be unrelated to either the number of high affinity TGF beta receptors, or the relative sensitivity to growth inhibition by TGF beta. Therefore, the TGF beta effect on EMA appears to be modulated at a level beyond receptors in these cells. EMA expression was also stimulated by sodium butyrate and dexamethasone (both differentiating agents) in some of the HMEC. The effect of butyrate on EMA expression is consistent with previous findings in which butyrate selectively enhanced production of milk fat globule antigens in the breast tumor cell line MCF-7, ZR-75-1, MDA-MB-134, and MDA-MB-468 cells. The coupled effects of TGF beta and SV40 T-transformation in enhancing the expression of EMA, and the possible effect of SV40 T increasing the responsiveness to TGF beta, may provide a new model for the study of the effect of growth factors in regulating specific gene expression in human breast epithelial cells.

Antibodies, Monoclonal↗
PubMed1989

Heterogeneous expression of erbB-2 messenger RNA in human breast cancer.

Amplification and mRNA expression of the erbB-2 gene was analyzed in 61 samples of primary human breast carcinoma. In the 57 samples where RNA could be isolated four different expression level groups were identified. Comparison of hybridization signal with that for beta-actin revealed that erbB-2 mRNA could not be detected in 6 of 57 samples (11%), was detected at normal levels in 32 of 57 samples (56%), showed 4- to 8-fold overexpression in 8 of 57 samples (14%), and showed 16- to 128-fold overexpression in 11 of 57 samples (19%). Examination of the DNA of the same set of samples revealed 6 of 61 samples (10%) with distinct gene amplification and 6 of 61 samples (10%) with possible gene amplification. The highest levels of erbB-2 overexpression were associated with gene amplification. Samples with 4- to 16-fold overexpression of the erbB-2 mRNA occurred without evident gene abnormalities. There was no association of erbB-2 expression or gene amplification with clinical stage of breast carcinoma or axillary lymph node involvement. The clear amplification of the erbB-2 gene may be associated with a significantly shorter time to treatment failure.

Actins↗
PubMed1989

Transformation of mouse mammary epithelial cells with the Ha-ras but not with the neu oncogene results in a gene dosage-dependent increase in transforming growth factor-alpha production.

An enhanced expression of transforming growth factor-alpha (TGF alpha) was demonstrated in two clones of NOG-8 mouse mammary epithelial cells, NOG-8 SR1 and NOG-8 SR2, that have been transformed by a v-Ha-ras oncogene. The amount of TGF alpha production in NOG-8 SR1 and NOG-8 SR2 cells was dependent on the level of p21ras expression in these clones, which directly correlated with their cloning efficiency in soft agar. There was also a decrease in the number of epidermal growth factor (EGF) receptors on the NOG-8 SR1 and NOG-8 SR2 cells that is proportional to the amount of TGF alpha secreted. These effects were specific for ras because neu-transformed NOG-8 cells grew in soft agar at a comparable level to NOG-8 SR2 cells yet did not show any increase in TGF alpha production or change in EGF receptor expression.

Animals↗
PubMed1989

Effect on growth and cell cycle kinetics of estradiol and tamoxifen on MCF-7 human breast cancer cells grown in vitro and in nude mice.

The effects of estradiol and tamoxifen (TAM) on the estrogen-dependent human breast cancer cell line MCF-7 grown in vitro and in nude mice were compared. The effect on growth was determined by cell number in vitro and by tumor growth curves in nude mice. The effects on the cell cycle kinetics were determined by repeated flow cytometric DNA analyses in vitro and in vivo and by the technique of labeled mitosis in nude mouse-grown tumors. Under in vitro conditions, estradiol induced a pronounced increase in S-phase fraction and cell number. TAM inhibited growth of MCF-7 cells with a concomitant increase in the G1 phase from 60% to 75%. In nude mice, MCF-7 only formed tumors in estradiol-supplemented mice. No differences were observed in growth and cell kinetics between 0.1 and 1.0 mg of estradiol. Daily i.p. injections of TAM resulted in tumor growth inhibition with shrinkage of tumors. The flow cytometric DNA analysis and percentage of labeled mitosis investigations revealed no significant differences in the proliferation kinetics of TAM-treated and control tumors. Calculating the cell loss factor demonstrated an increase from 69% in control tumors to 107% in TAM-treated tumors. These experiments have shown that the cell kinetic effect of TAM is different when MCF-7 cells are grown in vitro versus in vivo. In contrast to the in vitro data, the in vivo data indicate that the growth-inhibitory effect of TAM is not mediated through a perturbation of the cell cycle.

Animals↗