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C K Osborne

Publications and source records attributed to C K Osborne.

At least 163 records · Page 9Linked to original sources
PubMed1987

Biological differences among MCF-7 human breast cancer cell lines from different laboratories.

MCF-7 human breast cancer cells are used widely for studies of tumor biology and hormone mechanism of action. Conflicting results have often been obtained in studies reported from different laboratories. In this report several biological properties were studied in four MCF-7 cell lines obtained from different laboratories. MCF-7 (ATCC), MCF-7, MCF-7 (KO), and MCF-7 (S) demonstrated similar morphology in monolayer culture. Chromosome analysis revealed that three of the lines shared several structural chromosome alterations and marker chromosomes; however, MCF-7 (ATCC) was distinctly different with virtually no chromosomal alterations shared in common with the other lines. All four lines contained variable amounts of estrogen receptor (ER) and progesterone receptor (PgR). The growth rate of MCF-7 (ATCC) was 50% slower than that of the other lines, and, unlike the other three lines, cell proliferation was unaffected by estrogen or antiestrogen treatment despite the presence of receptors. Cloning efficiency of the four lines varied over a 10-fold range. Tumorigenicity in athymic nude mice also varied considerably among these lines. MCF-7 (ATCC) grew well in ovariectomized nude mice, while the other lines required estrogen supplementation. MCF-7 (S) and MCF-7 grew rapidly with estrogen supplementation; MCF-7 (KO) grew very slowly. Antiestrogen therapy inhibited growth of MCF-7, MCF-7 (S), and MCF-7 (KO) tumors, but it had no effect on MCF-7 (ATCC). These data demonstrate that MCF-7 lines from different laboratories may have unique biological properties, despite having a similar karyotype (MCF-7, MCF-7 (S), MCF-7 (KO]. The fundamental differences in karyotype and biological properties of the MCF-7 (ATCC), and the previously reported differences in DNA restriction fragment polymorphism analyses, demonstrate that this line is derived from an entirely different patient. Investigators should carefully document the source and identity of MCF-7 cells used in published experiments.

Agar↗
PubMed1987

Human breast cancer in the athymic nude mouse: cytostatic effects of long-term antiestrogen therapy.

We have investigated the effects of long-term estrogen withdrawal or tamoxifen therapy of MCF-7 human breast cancer cells growing in the athymic nude mouse to clarify mechanisms by which endocrine therapy inhibits tumor growth. Estrogen withdrawal with or without tamoxifen inhibited MCF-7 tumor growth, but did not cause significant regression, even after 4 months of treatment. Serial histologic studies of treated tumors revealed a reduction in mitotic rate but no significant gross or ultrastructural cytopathic changes. Treated tumors did show a modest increase in stromal fibrosis as well as occasional cytoplasmic or nuclear vacuolization, perhaps indicating early cytopathic effects. Cell viability was confirmed by cloning tumor cells in soft agar; cloning efficiency in treated tumors was similar to that in controls. Tumor fragments from treated mice were also viable and formed tumors when transplanted into estrogen-supplemented but not estrogen-deprived mice indicating continued hormone dependence. When estrogen-deprived or tamoxifen-treated mice were replenished with estrogen, cell proliferation was reactivated and tumor growth resumed. After 3-4 months of endocrine therapy, tumors began to regrow despite continued treatment suggesting the conversion to hormone independence. These studies suggest that in this model system, estrogen withdrawal and antiestrogen therapy work primarily by cytostatic rather than cytocidal mechanisms.

Animals↗
PubMed1987

Alteration of EGF-receptor binding in human breast cancer cells by antineoplastic agents.

Polypeptide growth factors bind to membrane receptors on human breast cancer cells and stimulate cell proliferation, suggesting that they may be important in growth regulation. Inhibition of the stimulatory effects of these factors might result in antineoplastic activity. Since cytotoxic drugs have been shown to alter cell membrane characteristics, we have examined the effects of a variety of antitumor drugs on the binding of epidermal growth factor (EGF) to the membrane receptor of human breast cancer cells. Twenty-four standard or investigational cytotoxic drugs were screened at a concentration of one-tenth the achievable peak plasma level for their ability to inhibit binding of 125I-EGF to its receptor in MCF-7 human breast cancer cells. Although at this concentration statistically significant inhibition of binding was observed with 11 drugs, the maximum inhibition observed was only 27%. Five agents, representing classes of drugs with different modes of action, were then studied in more detail. Of these, preincubation with 5-fluorouracil, 4-hydroperoxy-cylophosphamide and doxorubicin inhibited MCF-7 colony formation in a dose-dependent manner, but these drugs had no effect on EGF-binding even at a concentration of 10 times the peak plasma level. Preincubation of cells with vinblastine and cisplatin, however, resulted in both reduced colony survival and a parallel reduction in EGF receptor binding. Membrane integrity, as measured by trypan blue exclusion, was not altered. Scatchard analysis of EGF binding demonstrated that the major effect of cisplatin was a reduction in binding affinity. We conclude that cisplatin and vinblastine at high concentrations can inhibit the binding of EGF to human breast cancer cells offering an additional possible mechanism for their antiproliferative activity.

Antineoplastic Agents↗
PubMed1987

Survival from first recurrence: relative importance of prognostic factors in 1,015 breast cancer patients.

Univariate and multivariate analyses of potential prognostic factors for 1,015 women with recurrent breast cancer confirmed that the site of initial recurrence is an important determinant for predicting survival from the time of initial recurrence. However, both estrogen receptor (ER) status and axillary lymph node status at diagnosis, as well as the length of the disease-free interval, provide additional independent information for predicting patient survival after disease recurrence. Involved axillary lymph nodes at the time of initial diagnosis and/or lack of ERs may indicate a highly malignant tumor or a weak host defense, either of which might be related to short survival after relapse. Patients with ER-negative tumors recurred more often in visceral and soft-tissue sites, while patients with ER-positive tumors were more likely to recur in bony sites. However, for each metastatic site, receptor-positive patients had longer survival

Adult↗
PubMed1986

The use of restriction fragment polymorphisms to identify the cell line MCF-7.

We have recently documented variations in the level of N-ras gene amplification in independently passaged MCF-7 cells. To establish if these differences are due to a lack of genetic identity between current MCF-7 passages and the original cell line, we have performed karyological and restriction fragment length polymorphism (RFLP) analyses. Documentation of a combination of restriction fragment patterns which are characteristic of MCF-7 has been facilitated by an analysis of DNA from an early-passage of MCF-7 from the Michigan Cancer Foundation (MCF). In addition, such early passage cells and other MCF-7 lines also share a unique amplification of the N-ras oncogene. Using these criteria and karyotypic analysis it can be shown that a sample of MCF-7 obtained from the American Type Culture Collection (ATCC) was derived from a different individual than was the original MCF-7 cell line. It is important that researchers verify the relationship of current cell lines to the original MCF-7. Furthermore, the techniques described here provide a powerful tool which may be used to assess the identity of cell stocks.

Breast Neoplasms↗
PubMed1986

Adjuvant therapy of breast cancer: Southwest Oncology Group studies.

The Southwest Oncology Group has conducted a series of randomized studies of adjuvant therapy in patients with primary breast cancer and positive axillary nodes. The first study, during which combined chemotherapy with cyclophosphamide, methotrexate, 5-fluorouracil, vincristine, and prednisone (CMFVP) administered for 1 year was compared with single agent therapy with melphalan (L-PAM) for 2 years, was activated in 1975 and closed in 1978. Of the 366 patients who were eligible, 191 received L-PAM and 175 were given CMFVP. The 2 groups were comparable with regard to known prognostic factors. At a median follow-up of 8 years, CMFVP continues to be superior to L-PAM in disease-free (P = .005) and overall survival (P = .01). Thirty-five percent of patients on CMFVP have died compared with 46% on L-PAM. The greatest survival benefit is apparent in premenopausal women and women with 4 or more positive axillary nodes. Acute toxicity was more frequent with CMFVP than with L-PAM, but it was acceptable and reversible with both regimens. Long-term toxicity was limited to myeloproliferative disease in 2 patients on L-PAM and 1 on CMFVP. The second-generation series of studies, activated in 1979, were designed according to nodal status, estrogen receptor (ER) status, and menopausal status. We randomized ER-negative, node-negative patients to 6 months of combination chemotherapy or to no treatment. Because of slow accrual, the study was closed and patients are now being entered onto a similar intergroup study with the Eastern Cooperative Oncology Group. We randomized ER-negative, node-positive patients to either 1 or 2 years of CMFVP.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

A randomized trial of doxorubicin, mitoxantrone and bisantrene in advanced breast cancer (a South West Oncology Group Study).

New agents with increased activity and/or reduced toxicity are needed for the treatment of advanced breast cancer. The anthracene derivatives mitoxantrone and bisantrene had significant activity and acceptable toxicity in phase II trials. In an ongoing phase III trial we have now randomized 150 patients with advanced breast cancer to either doxorubicin (60 mg/m2), mitoxantrone (14 mg/m2) or bisantrene (260 mg/m2) i.v. q 3 weeks with re-randomization for cross-over at the time of progression to determine the relative efficacy and toxicity of these three agents. To be eligible, patients must have had only one previous chemotherapy regimen. ER positive patients must have failed endocrine therapy. Patients with CHF or severe cardiac disease were ineligible. In this preliminary evaluation, 117 patients are evaluable for response and 110 for toxicity. Median age for all patients is 58 years (range 26-78). The majority (86%) are postmenopausal. Fifty-nine percent percent of the patients have visceral dominant disease. Estrogen receptor is positive in 37%, negative in 39% and unknown in 24% of patients. Median performance status (SWOG) is 1, range 0-2. Objective responses have been observed on each arm (doxorubicin 9/35, mitoxantrone 6/38, bisantrene 6/44). Thirty-two patients are evaluable for cross-over response (doxorubicin 2/13, mitoxantrone 1/11, bisantrene 0/8). The predominant toxicity is leukopenia with a nadir WBC count less than 2000 in 45% of all courses administered. Leukopenia is similar with the three drugs. Significant nausea, vomiting and alopecia are common with doxorubicin and uncommon with the other agents. Congestive heart failure has been observed in one patient (doxorubicin). Definitive conclusions regarding the efficacy and toxicity of these agents await the completion of this trial.

Adult↗
PubMed1985

Endocrine therapy testing of human breast cancers in the soft agar clonogenic assay.

The human tumor soft agar cloning assay has been used to assess the biological effects of cytotoxic drugs and other agents on human cancers. In this study we have examined the effects of two hormonal agents, tamoxifen (Tam) and medroxyprogesterone acetate (MPA), on colony growth of the MCF-7 human breast cancer cell line as well as fresh human breast cancer specimens. Using standard criteria for a colony (greater than 50 cells or greater than 60 microns in diameter) Tam (1.0 microM) reduced MCF-7 colony formation by only 30% to 50%, and MAP (1.0 microM) had no effect. However, both agents dramatically reduced the formation of larger colonies; less than 10% of colonies larger than 124 microns survived Tam exposure, and less than 25% survived with MPA. In vitro sensitivity (less than 30% colony survival) of fresh human breast cancer specimens was observed infrequently with either Tam (1/39 evaluable assays) or MPA (3/36 evaluable assays). Colony growth of human breast cancer was unaltered when cells were plated in charcoal-stripped serum to reduce the endogenous estrogen concentration. In vitro sensitivity to Tam or MPA was not increased under these conditions. No correlation was found between estrogen receptor (ER) concentration and inhibition of colony survival with Tam or MPA. None of 16 assays from ER-positive specimens treated with Tam and 2 of 18 ER-positive specimens treated with MPA were sensitive in vitro. In contrast, 2 of 12 ER-negative specimens tested with Tam and 3 of 7 ER-negative specimens tested with MPA were sensitive in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1985

Adjuvant therapy for breast cancer with positive axillary nodes designed according to estrogen receptor status.

This is a preliminary report of the Southwest Oncology Group--Adjuvant Therapy in Operative Breast Cancer with Positive Axillary Nodes--in which therapy is randomized by estrogen receptor (ER) data. ER--patients receive either 1 or 2 years of CMFVP. The ER + group receive CMFVP for 1 year and/or hormonal therapy. ER + patients have a significant longer disease-free interval compared to ER--patients (P = 0.004). There was no significant difference in disease-free interval for ER--patients who receive either 1 or 2 years of CMFVP. The data for ER + patients is too preliminary to report for disease-free or total survival. Toxicity is acceptable because of frequent monitoring and examinations which results in the low percentage of life-threatening toxicity.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

Effect of estrogens and antiestrogens on growth of human breast cancer cells in athymic nude mice.

Endocrine therapy with estrogen deprivation or with antiestrogens results in tumor regression in a subset of patients with advanced breast cancer. To better understand the mechanisms by which estrogens and antiestrogens modulate breast cancer growth in vivo, we have studied the effects of endocrine manipulation on the development and growth of tumors derived from cultured human breast cancer cells in the athymic nude mouse. MCF-7 breast cancer cells were inoculated into 6-week-old female BALB/c athymic nude mice. Tumor growth did not occur in ovariectomized mice. Cells remained viable, however, since estrogen supplementation more than 30 days later resulted in tumor formation. Minimal tumor growth was observed in intact female nude mice which have low circulating estrogen levels. Tumor development and growth in ovariectomized or intact mice supplemented with 17 beta-estradiol in the form of a s.c. pellet were dose dependent; growth rates increased with estrogen doses ranging from 0.01 to 0.5 mg. Antiestrogen treatment with either tamoxifen or LY156758 caused transient stimulation of tumor growth, followed by a prolonged stationary phase. Growth resumed with estrogen supplementation. Treatment of mice bearing established MCF-7 tumors with estrogen withdrawal (removal of estrogen pellet) resulted in cessation of tumor growth, but not in tumor regression. Growth inhibition was also observed with antiestrogens and was dose dependent. However, tumor regression did not occur, even in mice treated with high doses of tamoxifen (serum concentration of 1.0 microM) for as long as 60 days. Tumor growth was restored in these mice with estrogen replenishment. Tumor cells also remained viable histologically despite prolonged (1 month) estrogen deprivation or antiestrogen therapy, although the mitotic index was markedly reduced. Similar observations were made with mice inoculated with the hormone-responsive ZR75-1 human breast cancer cells, but not with hormone-independent MDA-231 cells which were not influenced by estrogen or antiestrogen treatment. In summary, development and growth of MCF-7 and ZR75-1 tumors in nude mice are estrogen dependent. Endocrine therapy by estrogen deprivation or antiestrogen treatment inhibits tumor cell proliferation in nude mice, but does not cause tumor regression or loss of cell viability.

Animals↗
PubMed1984

Bisantrene, biological and clinical effects.

The clinical trials of bisantrene are still at an early stage. However, the many Phase II trials currently ongoing in the Southwest Oncology Group are too premature to draw any firm conclusions. However, there was general agreement during the discussion period that bisantrene does have definite clinical activity in certain tumors. These include metastatic breast cancer, non-Hodgkin's lymphoma, other types of lymphoma, leukemia, and, probably, ovarian cancer. There does not appear to be significant activity in malignant melanoma or in metastatic renal cancer. The conclusion of this symposium was that bisantrene is an active and reasonably well tolerated drug and that further trials are indicated.

Animals↗
PubMed1984

Correlations between estrogen receptor, progesterone receptor, and patient characteristics in human breast cancer.

The relationships between estrogen receptor, progesterone receptor, and a variety of patient characteristics are described for 2,977 women with primary breast cancer. Older women were more likely to be estrogen-receptor positive than younger women. When patient age and menopausal status were analyzed together, age was found to be the primary determinant of increased estrogen-receptor concentrations. There appeared to be no relationship with progesterone receptor for either age or menopausal status when these variables were analyzed separately. But premenopausal women had higher progesterone receptor concentrations than postmenopausal women when patients of the same age were compared, perhaps reflecting greater estrogen-mediated synthesis of progesterone receptor. Tumor size was negatively related to steroid receptor concentrations, but no relationships were observed between steroid receptors and either the number of positive axillary lymph nodes or the location of the primary tumor.

Adult↗
PubMed1984

Perturbation by insulin of human breast cancer cell cycle kinetics.

The growth of cultured human breast cancer cells is sensitive to physiological concentrations of insulin suggesting that it may regulate breast cancer growth in vivo. The mechanisms for the growth effects of insulin are poorly defined. In the present study, we examine the effects of insulin on the cell cycle kinetics of asynchronous MCF-7 human breast cancer cells growing in serum-free medium. When the [3H]thymidine labeling index is used to estimate the S-phase fraction, insulin added to asynchronously growing cells results in a time-dependent increase in the proportion of cells engaged in DNA synthesis. Computer analysis of DNA histograms obtained by flow cytometry of mithramycin-stained cells also shows a time-dependent progression of cells into and through the S-phase compartment. Sixteen hr after adding insulin to asynchronous cells, 66% of cells are in S-phase compared to 37% in controls. The effect of insulin on the cell cycle progression of MCF-7 cells is also dose dependent. Stimulation is observed with physiological insulin concentrations of 0.1 to 1.0 nM; maximal effects are observed with 1.0 to 10 nM insulin. Various insulin analogues enhance the progression of cells into S phase in proportion to their ability to bind to the insulin receptor in MCF-7 cells (porcine greater than or equal to chicken greater than guinea pig greater than deoctapeptide insulin), while unrelated peptide hormones have no effect on the cell cycle kinetics. Cell cycle analysis after the addition of colchicine to prevent mitosis and the reentry of cells into G1 demonstrates a shortened G1 in response to insulin. Continuous [3H]thymidine-labeling studies after the addition of colchicine suggest that the growth fraction is about 88% with or without insulin. In summary, insulin causes a marked perturbation of the cell cycle kinetics of MCF-7 human breast cancer cells by facilitating the transit of cells through G1. The data also suggest that this effect is mediated via the insulin receptor.

Animals↗