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M E Lippman

Publications and source records attributed to M E Lippman.

At least 145 records · Page 8Linked to original sources
PubMed1989

Secreted and cellular polypeptide patterns of MCF-7 human breast cancer cells following either estrogen stimulation or v-H-ras transfection.

The polypeptide patterns of MCF-7 human breast cancer cells (MCF-7gpt) and a stably v-H-ras-transfected subclone (MCF-7ras) have been analyzed following estradiol treatment. Since both estradiol and v-H-ras transfection increase tumorigenicity of MCF-7 cells, this study was designed to ascertain if specific changes in polypeptides were common in both treatments. Separation of cellular and secreted polypeptides was accomplished by 2-dimensional polyacrylamide gel electrophoresis, and the consequent patterns were analyzed with computer assistance. Estradiol treatment of the MCF-7gpt cells reduced the number of differences found in the polypeptide patterns between MCF-7gpt and MCF-7ras. Twelve cellular polypeptides were consistently modulated by either estradiol or v-H-ras, with four polypeptides clearly affected in the same way by both treatments. Polypeptides Gchc-0845 (Mr 54,000, pI 6.9) and Gchc-0902 (Mr 52,000, pI 6.3) were suppressed by estradiol and v-H-ras, while Gchc-1240 (Mr 34,000, pI 4.4) and Gchc-1396 (Mr 23,000, pI 5.3) were induced by estradiol and v-H-ras. Sixteen secreted polypeptides were altered by at least 2-fold subsequent to estradiol treatment or v-H-ras transfection. Transfection with v-H-ras had a greater effect than estradiol, stimulating the secretion of eight polypeptides and suppressing the secretion of seven polypeptides compared to estradiol which increased secretion of five polypeptides and decreased secretion of an additional three polypeptides, respectively. Synergistic effects by estradiol and v-H-ras were noted for three polypeptides. The secretion of Gcls-175 (Mr 50,000, pI 5.7) and Gcls-320 (Mr less than 14,000, pI 3.6, p-S2) was increased, while the secretion of Gcls-112 (Mr 76,000, pI 6.9) was decreased. Opposing effects of estradiol and v-H-ras were seen for seven polypeptides including the Mr 48,000 derivative of the Mr 52,000 protein (cathepsin D). These studies support the possibility that an extremely few, but specific polypeptides are regulated in association with quite diverse tumorigenic stimuli in MCF-7 human breast cancer cells.

Breast Neoplasms↗
PubMed1989

Transforming growth factors type beta 1 and beta 2 are equipotent growth inhibitors of human breast cancer cell lines.

At least one member of the TGF-beta family, TGF-beta 1, has been previously shown to inhibit the anchorage-independent growth of some human breast cancer cell lines (Knabbe et al., 1987; Arteaga et al., 1988). Members of the TGF-beta family might, therefore, provide new strategies for breast cancer therapy. We have studied the inhibitory effects of TGF-beta 1 and TGF-beta 2 on the anchorage-independent growth of the oestrogen receptor-negative cell lines MDA-MB-231, SK-BR-3, Hs578T, MDA-MB-468, and MDA-MB-468-S4 (an MDA-MB-468 clone not growth inhibited by EGF) and the estrogen receptor-positive cell lines MCF7, ZR-75-1, T-47D. TGF-beta 1 and TGF-beta 2 caused a 75-90% growth inhibition of MDA-MB-231, SK-BR-3, Hs578T, and MDA-MB-468 cells and a 50% growth inhibition of ZR-75-1 and early passage (less than 100) MCF7 cells. T-47D cells responded to TGF-beta only in serum-free conditions in the presence of IGF-1 or EGF. The growth of MDA-MB-468-S4 cells and late passage (greater than 500) MCF7 cells was not inhibited by TGF-beta 1 or TGF-beta 2. TGF-beta-sensitive MCF7 and MDA-MB-231 cells did not respond to Muellerian inhibiting substance (MIS), a TGF-beta-related polypeptide. TGF-beta 1 or TGF-beta 2 were mutually competitive for receptor binding with a similar affinity (Kd 25-130 pM, 1,000-13,000 sites per cell). To determine the time course of the TGF-beta effect, an anchorage-dependent growth assay was carried out using MDA-MB-231 cells. Growth inhibition occurred at 6 days, and cell-cycle changes were seen 12 hr after the addition of TGF-beta. Cells accumulated in the G1 phase and were thus inhibited from entering the S-phase. These data indicate that TGF-beta is a potent growth inhibitor in most breast cancer cell lines and provide a basis for studying TGF-beta effects in vivo.

Anti-Mullerian Hormone↗
PubMed1989

Mechanisms of normal and malignant breast epithelial growth regulation.

In this presentation we review information highlighting the multiple roles of both steroidal and polypeptide regulators of mammary epithelial cell growth with some additional emphasis on the work of our laboratory. The effects of both classes of hormones are complex and involve multiple interactions with epithelial components (malignant or normal) and the stromal compartment. Estrogens induce growth regulatory polypeptide growth factors which are responsible for many of the induced phenotypic effects in hormone-dependent breast cancer. Progression of hormone-dependent breast cancer to hormone independence probably involves multiple genetic mechanisms of oncogene activation, loss of the estrogen receptor, or loss of hormone responsivity of other gene products. Initial carcinogenesis and progression of mammary epithelium to cancer probably also requires both proliferative stimuli (estrogen, polypeptide growth factors) and genetic damage, leading to qualitatively different hormonal responses (hormone responsive cancer). New therapeutic strategies based on these biological considerations are emerging, including a variety of approaches which interfere at multiple points with ability of ligand to induce receptor signaling.

Breast↗
PubMed1989

Progression of human breast cancer cells from hormone-dependent to hormone-independent growth both in vitro and in vivo.

We have isolated a series of sublines of the hormone-dependent MCF-7 human breast cancer cell line after selection both in vivo and in vitro for growth in the presence of subphysiological concentrations of estrogens. These sublines represent a model system for study of the processes leading to hormonal autonomy. The cells form growing tumors in ovariectomized athymic nude mice in the absence of estrogen supplementation but retain some responsivity to estrogen as determined by stimulation of the rate of tumor growth in vivo and by induction of progesterone receptor. An ovarian-independent but hormone-responsive phenotype may occur early in the natural progression to hormone-independent and unresponsive growth in breast cancer. We observed no change in the affinity or decrease in the level of expression of estrogen receptors and progesterone receptors among the sublines and the parental cells. Epidermal growth factor receptors are not overexpressed in ovarian-independent cells. Thus, altered hormone receptor expression may be a late event in the acquisition of a hormone-independent and unresponsive phenotype. Sublines isolated by in vivo but not in vitro selection are more invasive than the parental cells both in vivo and across an artificial basement membrane in vitro. Thus, as yet unknown tumor-host interactions may be important in the development of an invasive phenotype. Furthermore, acquisition of the ovarian-independent and invasive phenotypes can occur independently.

Animals↗
PubMed1989

Regulation of breast cancer cells by hormones and growth factors: effects on proliferation and basement membrane invasiveness.

The current understanding of the regulation of breast cancer cell proliferation and invasiveness by hormones and growth factors is reviewed. It has been shown that polypeptide growth factors are involved in hormone-independent breast cancer, and are sometimes oestrogen-regulated in hormone-responsive models. Basement-membrane invasiveness, relating to the metastatic potential of these cells, is also stimulated by oestrogen in hormone-dependent models, elevated in hormone-independent models, and is growth factor sensitive. Further understanding of the differential effects of growth factors on breast cancer cell proliferation and invasiveness should facilitate better therapeutic exploitation of regulation at this level.

Animals↗
PubMed1989

Breast conservation versus mastectomy: distress sequelae as a function of choice.

Between 1981 and 1984, 93 stage I and II breast cancer patients were entered onto a trial at the National Cancer Institute (NCI) randomizing patients to excisional biopsy plus radiation v mastectomy. Between 1984 and 1987, 98 stage I and II breast cancer patients were entered onto a behavioral study in Pittsburgh, approximately 70% of whom elected to have breast conservation surgery. Patients at both sites were assessed three to five days postsurgery, and again at 3-month's follow-up, using a well-validated mood measure, the Profile of Mood States (POMS). There were no demographic or disease differences between the two samples. In the Pittsburgh sample, using a repeated measures multivariate analysis of covariance (MANCOVA) analysis, after adjusting for menopausal status and radiotherapy and chemotherapy toxicity, the conservation group was psychologically worse off (F = 2.7, P less than .03). For example, they were significantly more distressed over time (F = 5.5, P less than .02), and more depressed in general (F = 9.2, P less than .005). Using Karnofsky ratings, the two groups were identical in terms of disability at 3-month's follow-up. In contrast, for the NCI patients participating in the randomized trial, after adjusting for chemotherapy and radiotherapy treatments, reported overall distress decreased over time (F = 17.4, P less than .0001) for all patients, irrespective of treatment group, and the between-groups MANCOVA was not significant. Thus, when comparing the two samples, when "choice" played a major role, the conservation patients were psychologically worse off--at least at 3-month's follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Affect↗
PubMed1989

Can oncologists add?

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Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Fluorouracil and high-dose leucovorin in previously treated patients with metastatic breast cancer.

The efficacy and toxicity of leucovorin 500 mg/m2 administered intravenously (IV) over 30 minutes daily for five days followed in one hour by fluorouracil (5-FU) 375 mg/m2 administered IV daily for five days, each given every 3 weeks, was assessed in 54 previously treated patients with metastatic breast cancer. An overall objective response rate of 24% was achieved (95% confidence interval, 13% to 38%), with an additional 56% of patients maintaining stable disease. Eleven of 12 patients who responded had received previous 5-FU therapy. Toxicity of this regimen included grade 3 diarrhea in 13%, grade 3 or 4 mucositis in 33%, grade 3 or 4 granulocytopenia in 65%, and grade 3 or 4 thrombocytopenia in 19%. Delay of treatment was required for hematologic toxicity in 44 patients. Thirty-eight patients required dose reductions due to toxicity. Biochemical evaluation of tumor biopsy specimens obtained from 17 patients used as their own controls with and without leucovorin was performed. These studies reveal an increased stabilization of the 5-fluorodeoxyuridylate (FdUMP)-thymidylate synthase (TS) folate ternary complex with the addition of leucovorin. There was a 71% +/- 14% occupancy or inhibition of the enzyme with the use of both 5-FU and leucovorin, v 30% +/- 13% for 5-FU alone (P2 less than .037). The percent TS bound in responding patients was substantially higher than in those patients with progressive disease. Finally, the mean total tumor TS pre-therapy in seven patients was 31 fmol/mg compared with a mean of 81 fmol/mg in these same seven patients 24 hours after therapy. This 2.6-fold increase suggests that there is an induction of the enzyme, TS, with 5-FU treatment.

Adult↗
PubMed1989

Transforming growth factor alpha production and epidermal growth factor receptor expression in normal and oncogene transformed human mammary epithelial cells.

We have characterized the expression of transforming growth factor alpha (TGF alpha) and its receptor, the epidermal growth factor receptor (EGF-R), in normal and malignantly transformed human mammary epithelial cells. Human mammary epithelial cells were derived from a reduction mammoplasty (184), immortalized by benzo-a-pyrene (184A 1N4), and further transformed by the oncogenes simian virus 40 T (SV40 T), v-Ha-ras, and v-mos alone or in combination using retroviral vectors. 184 and 184A 1N4 cells require EGF for anchorage-dependent clonal growth. In mass culture, they secrete TGF alpha at high concentrations and exhibit an attenuated requirement for exogenous EGF/TGF alpha. SV40 T transformed cells have 4-fold increased EGF-R, have acquired the ability to clone in soft agar with EGF/TGF alpha supplementation, but are not tumorigenic. Cells transformed by v-mos or v-Ha-ras are weakly tumorigenic and capable of both anchorage dependent and independent growth in the absence of EGF/TGF alpha. Cells transformed by both SV40 T and v-Ha-ras are highly tumorigenic, are refractory to EGF/TGF alpha, and clone with high efficiency in soft agar. The expression of v-Ha-ras is associated with a loss of the high (but not low) affinity binding component of the EGF-R. Malignant transformation and loss of TGF alpha/EGF responsiveness did not correlate with an increase in TGF alpha production. Thus, TGF alpha production does not appear to be a tumor specific marker for human mammary epithelial cells. Differential growth responses to EGF/TGF alpha, rather than enhanced production of TGF alpha, may determine the transition from normal to malignant human breast epithelium.

Animals↗
PubMed1989

Role of an estrogen receptor-dependent mechanism in the regulation of estrogen receptor mRNA in MCF-7 cells.

We have previously demonstrated that regulation of estrogen receptor (ER) expression in MCF-7 breast cancer cells is a complex process involving transcriptional and posttranscriptional regulation by estradiol. Treatment of MCF-7 cells with estradiol results in the down-regulation of receptor expression; posttranscriptional suppression of receptor mRNA appears to be the predominant mechanism. To determine whether posttranscriptional regulation of ER gene expression is mediated by an ER-dependent mechanism independent of protein synthesis, we have used the competitive estrogen antagonist, 4-hydroxytamoxifen, and the inhibitor of protein synthesis, cycloheximide, to study regulation of ER mRNA by estradiol. 4-Hydroxytamoxifen had no effect on the steady-state level of receptor mRNA and effectively blocked the suppression of ER mRNA by estradiol. The metabolic inhibitor, cycloheximide, was unable to prevent the estrogen induced decrease in ER mRNA. These data provide evidence that the posttranscriptional suppression of ER expression through estradiol is mediated through the ER independent of protein synthesis. A study of the effects of estradiol on the steady-state levels of nuclear and cytoplasmic receptor mRNA suggest that posttranscriptional suppression is a nuclear event.

Breast Neoplasms↗
PubMed1989

Anti-epidermal growth factor receptor antibodies inhibit the autocrine-stimulated growth of MDA-468 human breast cancer cells.

The response of malignant and nonmalignant human breast cell lines to the growth inhibitory effects of monoclonal antibodies against the epidermal growth factor (EGF) receptor was studied. A series of human breast cell lines, which express EGF receptor, were used: MDA-468, MDA-231, and Hs578T human breast cancer cells and the transformed human mammary epithelial cell lines 184A1N4 and 184A1N4-T that have been benzo[a]pyrene immortalized and further transformed with SV40T, respectively. Four antibodies of two different classes were tested: 225 immunoglobulin G (IgG), 108.4 IgG, 96 immunoglobulin M (IgM), and 42 IgM. All four antibodies inhibited the anchorage-dependent and -independent, EGF-stimulated growth of 184A1N4 and 184A1N4-T cells, respectively, and this growth inhibition could be reversed by the addition of increasing concentrations of EGF. In contrast, the antibodies inhibited the anchorage-dependent and -independent growth of MDA-468 cells in the absence of exogenous EGF suggesting that the antibodies were acting to block access of an endogenously produced ligand to the EGF receptor. In the presence of antibody and increasing concentrations of EGF, MDA-468 cell growth was first stimulated then inhibited as the EGF concentration increased, thus, uncovering the growth stimulatory potential of low concentrations of EGF in these cells. Data is presented that indicates MDA-468 cells secrete a transforming growth factor with autocrine growth stimulatory capabilities. The growth of MDA-231 and Hs578T cells, which contain activated ras oncogenes, was not inhibited by the antibodies and the growth of these cell lines was not stimulated by EGF. Of the cell lines studied only MDA-468 cells appear to possess an autocrine growth stimulatory capacity.

Antibodies, Monoclonal↗
PubMed1989

The effects of a constitutive expression of transforming growth factor-alpha on the growth of MCF-7 human breast cancer cells in vitro and in vivo.

It has been suggested that transforming growth factor-alpha (TGF-alpha) is a mitogenic autocrine growth factor for human breast cancer cells, responsible for mediating the mitogenic effects of 17 beta-estradiol (E2) in responsive cells. To test this hypothesis we have introduced eukaryotic expression vectors directing the expression of TGF-alpha mRNA into E2-responsive MCF-7 human breast cancer cells. Transfected cells produce levels of TGF-alpha equivalent to or greater than those produced by both E2-stimulated MCF-7 cells and hormone-independent MDA-MB-231 cells. One transfected clone (H8) secretes sufficient TGF-alpha to fully down-regulate EGF-R expression. However, both of the transfected clones that constitutively secrete elevated levels of TGF-alpha (A8 and H8) respond to E2 stimulation in vitro by increasing the rate of cellular proliferation and inducing PGR synthesis. The basal proliferative capacity of H8 and A8 cells is equivalent to that of the parental cells and to cells transfected only with the G418 (neomycin) resistance gene. Furthermore, the TGF-alpha cDNA-transfected clones do not form tumors in ovariectomized athymic nude mice without E2 supplementation. Thus, the precise role of TGF-alpha in mediating either the in vivo or the in vitro mitogenic effects of E2 in MCF-7 human breast cancer cells remains unclear. While TGF-alpha expression may be essential, it is not sufficient alone to induce the fully E2-independent phenotype. Thus, TGF-alpha may function in combination with other E2-induced growth factors to control breast cancer proliferation and tumorigenesis.

Breast Neoplasms↗
PubMed1989

Analysis of insulin-like growth factor I gene expression in malignancy: evidence for a paracrine role in human breast cancer.

Insulin-like growth factor I (IGF-I) activity has been reported to be produced by several human cancers. Identification of RNAs transcribed from the IGF-I gene has been complicated by the detection of multiple hybridizing bands on Northern analysis. To determine if any of these RNAs are transcribed from the IGF-I gene, we have used a sensitive and specific ribonuclease (RNAse) protection assay for IGF-I. We have also studied the breast cancer tissue expression of IGF-I using in situ hybridization histochemistry. We have found no IGF-I mRNA in breast (zero of 11) or colon cancer (zero of 9) cell lines; both of these tumors have been previously reported to express IGF-I mRNA. However, three of three neuroepithelioma and one of two Ewing's sarcoma cell lines express IGF-I mRNA; therefore, in these tumors IGF-I may be an autocrine growth factor. In contrast to breast cancer cell lines, RNA extracted from breast tissues has easily detectable IGF-I mRNA. In situ hybridizations show that IGF-I mRNA is expressed in the stromal cells, and not by normal or malignant epithelial cells. These findings suggest that although IGF-I is not produced by breast epithelial cells it may function as either a paracrine stimulator of epithelial cells or an autocrine stimulator of stromal cells.

Blotting, Northern↗
PubMed1989

The inter-relationships between ovarian-independent growth, tumorigenicity, invasiveness and antioestrogen resistance in the malignant progression of human breast cancer.

Among the processes contributing to the progressive acquisition of the highly malignant phenotype in breast cancer are ovarian-independent growth, antioestrogen resistance and increased metastatic potential. We have previously observed that increased invasiveness and development of ovarian-independent growth occur independently. In an attempt to define the inter-relationships between these processes further, we have compared the phenotypes of ovarian-independent, invasive and antioestrogen-resistant sublines of the ovarian-dependent human breast cancer cell line MCF-7. Cells acquiring ovarian-independent growth can retain sensitivity to anti-oestrogens. One clone of MCF-7 cells selected for stable antioestrogen resistance has become non-tumorigenic but its invasive potential remains unaltered. Thus, acquisition of some characteristics of the progressed phenotype can occur independently. This phenomenon of independent parameters in phenotypic progression could partly explain the considerable intra- and intertumour heterogeneity characteristic of breast tumours.

Animals↗