Implementation of an osteoporosis research program with a mobile dual-energy X-ray absorptiometry unit: the Montana/Wyoming experience.

To expedite recruitment, and subject participation, for a large clinical osteoporosis therapy trial utilizing the bisphosphonate ibandronate, an integrated network of 13 satellite clinical sites was developed, linked by a mobile clinic vehicle transporting a dual-energy X-ray absorptiometry (DXA) unit. A predominantly rural area of the United States (Montana, northern Wyoming) was accessed for the project, due to the large pool of potential subjects living in this area who were not yet involved in osteoporosis clinical studies. The results of the project to date (through 10 months) confirm the feasibility of such a study design, with 1774 subjects screened by DXA for the study, and 280 (15.8%) accepted. The mobile DXA unit has functioned according to specifications for a stationary DXA machine, with the stability of spine phantom measurements over 10 months assessed as a coefficient of variation of 0.46%. The success of the project validates the concept of performing clinical osteoporosis therapy trials in previously underutilized rural community settings, facilitated by a satellite site network and mobile clinic.

Relationship of standardized mitotic indices to other prognostic factors in breast cancer.

OBJECTIVE: To examine the relationship between mitotic index (MI), calculated from direct microscopic counts, and other prognostic features in breast cancer. DESIGN: Mitotic index was based on direct microscopic observations of mitotic figures in 10 consecutive microscopic fields, and the average cell number was determined by counts of population density in three of those fields. Tumor grade and type were established from tissue sections, whereas metastases were detected in lymph node biopsy, chest roentgenograms, and bone scan. Estrogen receptor (ER) and progesterone receptor (PgR) levels were determined by flow cytometry. RESULTS: The MI for 242 patients ranged from 0.2 to 37.6, with a mean of 5.8 mitoses per 1000 cells. More than 85% of the tumors with an MI below 1.0 were diploid and contained an S-phase fraction of 6.7% or less. In contrast, more than 75% of tumors with an MI above 5.0 were aneuploid with more than 6.7% of cells in S-phase. There was an inverse relationship between ER and PgR status and MI. Eighty percent of tumors with an MI less than 1.0 were both ER and PgR positive while only 25% of those with an MI above 10.0 were both ER and PgR positive. Receptor-positive tumors with high S-phase and MI values had ER and PgR levels below 100 fmol/mg. CONCLUSIONS: Lower MI values calculated from direct cell counts are correlated with negative node status, diploid DNA content, low S-phase fraction, and positive receptor status. Thus, there is a significant relationship between objective MI values and several other factors that predict the probability of breast tumor recurrence.

Estrogen receptors in parotid tumors.

A regulatory role for estrogen in the growth of salivary gland tumors has been hypothesized. In the current study we attempted to establish whether or not benign and malignant parotid tumor cells express estrogen receptors. Immunohistochemical studies were performed with samples of tissue from 72 patients with benign tumors and 26 patients with malignant tumors originating in the parotid gland. Replicate tissue sections were stained with two sets of reagents specific for the receptors. There was no immunohistochemical evidence for the presence of estrogen receptors in any specimen examined. In contrast, cells in tissue sections from a breast cancer control were consistently positive for estrogen receptor using the same techniques. These observations show that the estrogen receptor concentration in parotid tumors is below the level required for visualization by immunohistochemical techniques. Thus, it is unlikely that this receptor plays a major role in regulating parotid tumor growth.

Relationship between low estrogen receptor values and other prognostic factors in primary breast tumors.

BACKGROUND: The current study compared the immunocytochemical expression of estrogen (ER) and progesterone (PgR) receptors by malignant breast cells to the hormone receptor concentrations reported from radioligand assays. These values were examined in relation to DNA ploidy and the fraction of cells in S phase. METHODS: ER and PgR concentrations, DNA ploidy, and S-phase fractions were measured by standard techniques with 124 samples of invasive ductal carcinoma. Suspensions of tumor cells were examined by immunocytochemical assay (ICA) for the percentages of ER and PgR positive cells. RESULTS: Twenty-six of the 38 tumors from patients 50 years of age or younger were classified as high S-phase fraction, and 28 tumors had aneuploid levels of DNA. The 20 ER positive tumors each contained less than 100 fmol/mg. Thirty-nine of the 86 tumors from patients older than 50 years were classified as high S phase, and 41 were aneuploid. Sixty-five samples were considered ER positive by radioligand assay. ICA showed that tumors in either age group with less than 40 fmol/mg did not contain ER positive cells. The proportion of samples with PgR levels between 10 and 100 fmol/mg was small, and fewer PgR positive tumors were categorized as negative when examined by ICA for receptor containing cells. The reclassification of the hormone receptor status of a tumor based on ICA appeared to be independent of S-phase and ploidy values. CONCLUSIONS: Tumors that are classified as ER or PgR positive based on accepted cutoff values for radioligand assays may actually be receptor negative because the tumors do not appear to contain receptor positive cells.

Immunocytochemical analysis of hormone receptors with malignant cells separated from human mammary tumors.

The authors compared radioligand assays with immunocytochemistry assays to establish the hormone receptor status of malignant mammary tumors. This study differed from previous work in that immunochemistry assays were used with tumor cell effluents rather than with intact histologic sections. The results showed a 90% qualitative agreement between immunocytochemistry assays and radioligand assays in identifying estrogen receptor (ER)- or progesterone receptor (PgR)-positive and ER- or PgR-negative malignant tumors. However, only 31% of the cells from receptor-positive patients expressed ER, and only 24% of the cells contained PgR. The data showed a 73% agreement between immunocytochemistry and radioligand assays for ER when cases were categorized as strongly positive (> 100 fmol/mg and > 10% stained cells), intermediately positive (3-100 fmol/mg and .1% to 10% stained cells), or negative in both assays. Progesterone receptor values for the three categories showed an agreement between assays of 82%. These observations suggest that immunocytochemical analysis of isolated populations of tumor cells may be a useful means of complimenting radioligand assays in selecting patients for antihormone therapy.

Characterization of inhibitory activities secreted by THP-1 leukemia cells and regulation by interferon-gamma.

Cells of the monocytic leukemia line, THP-1, mimic several of the functional characteristics of activated monocytes and macrophages following incubation in the tumor promoting agent, mezerein. The current paper explores the nature of the factors in medium conditioned by THP-1 cells which inhibit cell growth and the effects of interferon-gamma (IFN gamma) on their synthesis. Activity inhibiting the growth of the MDA-MB-415 mammary carcinoma line migrated in a pH range of 6.5 to 7.5 and could be resolved into 2 peaks, one corresponding to interleukin-1 beta (IL-1 beta) and the other with an apparent average molecular weight of 43 Kd. Antisera against tumor necrosis factor alpha and beta (TNF alpha and beta) and monocyte colony stimulating factor (M-CSF) had no effect on the 43 Kd inhibitor. IFN gamma enhanced the secretion of IL-1, but decreased the production of the 43 Kd inhibitor. The L-929 cell cytotoxicity assay and an ELISA were used to show that the amount of TNF alpha present was less in medium from IFN gamma treated cells. THP-1 cells also produced an IFN gamma repressed activity separating at pH 4.8 to 6.1 which inhibited the response of T cells to IL-1 in a thymocyte co-mitogenic assay. The inhibitors expressed by THP-1 cells may be comparable to the cytotoxic and cytostatic activities expressed by activated human monocytes and macrophages.

Antibodies and their role in interleukin-1 research.

The preceding paragraphs describe several uses of specific antibodies to IL-1. Standard radioimmunoassays and ELISA procedures were developed with demonstrated utility in studies attempting to quantitate the cytokine in cell culture fluids. In part, antibody-based assays circumvent the problems associated with bioassays. Bioassays are difficult to perform, often lack specificity due to the presence of competing cytokines and are insensitive when used with complex biological fluids due to non-specific protein binding and the presence of IL-1 antagonists. Thus, bioassays have not been broadly applicable with specimens in a clinical setting. In contrast, monoclonal antibodies and polyclonal antisera have provided a means of identifying functionally important regions of the IL-1 molecule, monitoring the post-translational processing of IL-1 which may include biologically inactive moieties, and developing new assays as illustrated by cell blot procedures.

Squamous cell carcinomas often produce more than a single bone resorption-stimulating factor: role of interleukin-1 alpha*.

Several cultured human squamous cell carcinoma cell lines (SCC-4, SCC-12B2, SCC-12F2, EC-GI-10, and BEN) and one normal keratinocyte line (Epy-1) were investigated for the production of bone resorption-stimulating activity (BRSA). Conditioned medium (CM) from each of the six cell lines stimulated bone resorption in neonatal mouse calvariae in culture. The BRSA of SCC-12F2 and EC-GI-10 was inhibited completely by antibody to interleukin-1 alpha (IL-1 alpha), whereas the BRSA in CM from the BEN, SCC-4, SCC-12B2, and Epy-1 cell lines was only partially inhibited by anti-IL-1 alpha. Addition of indomethacin to the calvarial cultures also partially inhibited the BRSA from EC-GI-10, SCC-4, SCC-12B2, and Epy-1 cells; the BRSA from BEN and SCC-12F2 cells was inhibited completely by indomethacin. cAMP production by calvariae was determined after a 60-min incubation with CM. CM from EC-GI-10, BEN, SCC-4, and Epy-1 stimulated cAMP production by bone. Preincubation of CM from BEN, EC-GI-10, SCC-4, and Epy-1 cells with two antisera against PTH-related protein [PTHrP; one specific for two PTHrP-(1-141), the other recognizing both PTHrP-(1-40) and PTHrP-(1-141)] completely inhibited the cAMP-stimulating activity. Using specific enzyme-linked immunosorbent assays for IL-1 alpha and IL-1 beta, IL-1 alpha was measured in CM of the SCC-4, SCC-12B2, SCC-12F2, and Epy-1 cell lines. IL-1 beta was undetectable (less than 0.1 ng/ml) in CM from all cell lines. Our findings indicate that the BRSA secreted by SCC-12F2 cells can be accounted for largely or entirely by IL-1 alpha, while the activity produced by SCC-12B2 includes IL-1 alpha and another unknown factor(s). The BRSA produced by EC-GI-10, BEN, SCC-4, and Epy-1 cells includes both IL-1 alpha and PTHrP. We conclude that IL-1 alpha may be a more prevalent and biologically significant component of the BRSA produced by SCCs than previously recognized.

Secretion of interleukin-1 beta by a leukemia cell line in response to lipopolysaccharide and mezerein.

The acute monocytic leukemia cell line, THP-1, is frequently used as a model to study the mechanism of cell-mediated immune response. The model is justified, in part, because THP-1 cells can be induced to express features of activated peripheral blood monocytes or tissue macrophages. The current investigation, however, demonstrates that THP-1 cells differ from normal monocytes in their secretion of interleukin-1 beta (IL-1 beta) following exposure to reagents that induce synthesis. For example, LPS treatment alone did not result in IL-1 beta secretion and very low concentrations were observed when lipopolysaccharide (LPS)-treated cells were simultaneously incubated with silica or silica in combination with hydroxyurea. Silica-enhanced release of IL-1 was related to changes in cell membrane permeability. Recombinant interferon-gamma (rIFN gamma) alone did not induce IL-1 beta secretion and did not significantly increase secretion by LPS- and silica-stimulated cells. In contrast, mezerein stimulation led to higher extracellular concentrations of IL-1 beta and rIFN gamma augmented secretion by mezerein-treated cells. Isoelectrofocusing of conditioned medium and titration of pooled fractions showed a direct correlation between extracellular levels of biologically active and immunoreactive IL-1. The role of IFN gamma in stimulating IL-1 beta secretion was not related to an enhancement of viability or an increase in the proportion of mezerein-treated cells synthesizing DNA. It was concluded that mezerein's regulation of secretion by THP-1 cells depended on the expression of monocyte features, including cell adherence and responsiveness to IFN gamma.

Demonstration of IL-1 alpha, and IL-1 beta secretion by the monocytic leukemia cell line, THP-1.

This study examined the secretion of IL-1 alpha and IL-1 beta by THP-1 leukemia cells following activation with mezerein and promotion of synthesis by interferon (IFN-gamma). Interleukin-1 (IL-1) was not detected by co-mitogenic thymocyte assays of crude supernates. Isoelectrofocusing of concentrated medium showed that all biologically active IL-1 migrated at a pH of 6.8-7.2, indicating that the major secreted form was IL-1 beta. Double antibody ELISA confirmed the presence of IL-1 beta, but failed to detect IL-1 alpha in isofocused fractions. Although it appeared that THP-1 cells do not secrete IL-1 alpha; an inhibitor of thymocyte response to IL-1 was present in conditioned medium, migrated in an acidic pH range and masked the expression of biologically active rIL-1 alpha and rIL-1 beta. In contrast, IL-1 alpha was detected using a cell blotting assay. This technique permitted visualization of subpicogram levels of IL-1 when secreted by cells attached to an immunoblotting paper. Cell blotting showed that a greater proportion of attached cells incubated for 24 h in medium containing mezerein and IFN-gamma secreted IL-1 than cells in control medium. In conclusion, the amount of immunoreactive or biologically active IL-1 alpha secreted by stimulated THP-1 cells appeared to be much lower than that reported for human peripheral blood monocytes.

Two squamous cell carcinomas not associated with humoral hypercalcemia produce a potent bone resorption-stimulating factor which is interleukin-1 alpha.

Conditioned medium (CM) from two squamous cell carcinoma cell lines, SCC-9 and SCC-13, stimulated bone resorption in neonatal mouse calvariae in organ culture. Enhanced bone resorption induced by CM was associated with an increased production of prostaglandin-E2 (PGE2) by the calvariae. Complete inhibition of stimulated PGE2 synthesis by indomethacin only partially inhibited bone resorption-stimulating activity (BRSA) in the CM. Neither SCC-9 nor SCC-13 CM stimulated cAMP production in rat osteosarcoma cells (ROS 17/2.8). The BRSA in CM was completely inhibited by an antibody to interleukin-1 alpha (IL-1 alpha). Fractionation of SCC-9 CM by gel filtration and HPLC ion exchange chromatography revealed a single peak of BRSA and PGE2 synthesis-stimulating activity at 17-20K (termed SCMII). In mouse calvariae, SCMII increased medium Ca2+ and PGE2 in a dose-dependent manner at concentrations from 20 ng protein/ml to a maximum of 500 ng protein/ml. Preincubation of SCMII with antibody to IL-1 alpha completely inhibited SCMII-induced bone resorption. SCMII also enhanced thymocyte proliferation with activity that was equivalent to 353 U/ml IL-1. Antibodies to IL-1 beta and tumor necrosis factor had no effect on SCMII-induced bone resorption. Using specific enzyme-linked immunosorbent assays for IL-1 alpha and IL-1 beta, IL-1 alpha was measured in high concentrations in both crude and partially purified fractions of SCC-9 and SCC-13 CM. In contrast, IL-1 beta was either undetectable or present in amounts below those that stimulate bone resorption. In addition, SCMII did not enhance cAMP production in bone cells. We conclude that the BRSA produced by the two squamous cell carcinoma cell lines SCC-9 and SCC-13 is IL-1 alpha.

Correlation between human cell growth response to interleukin 1 and receptor binding.

Human recombinant interleukin 1 alpha (IL-1 alpha) and IL-1 beta inhibited the replication of the mammary tumor cell line, MDA-MB-415; stimulated division in the colon carcinoma, SW-48; and had no effect on the growth of the milk mammary line, HBL-100. Inhibition of growth was reflected in a significant decrease in DNA synthesis accompanying a transient increase in RNA synthesis. Specific binding of 125I-labeled recombinant IL-1 beta by MDA-MB-415 and SW-48 reached a maximum by 2 h of incubation, and an equivalent amount was bound by each cell type. Binding was inhibited in a dose-dependent manner by unlabeled IL-1 alpha or IL-1 beta. Scatchard plot analysis revealed that MDA-MB-415 cells expressed approximately 700 binding sites with an apparent dissociation constant of 8.8 x 10(-10) M. Reversibility of growth inhibition was independent of dose or time of incubation, but DNA synthesis did not return to control values. Flow cytometric analysis of DNA content showed that growth inhibition was cell cycle phase nonspecific with a slight reduction in the proportion of cells in S phase. The major conclusion from these studies was that inhibition or stimulation of malignant cell growth by IL-1 was related to the presence of receptor sites.

Regulation by interferon gamma of function in the acute monocytic leukemia cell line, THP-1.

THP-1 is an acute monocytic leukemia cell line which acquires phenotypic and functional monocytoid-like features following incubation with mezerein. The current study concerned the modulation of these features by rIFN gamma. rIFN gamma induces the time-dependent enhancement of HLA-DR expression in the presence or absence of mezerein but has no effect on the expression of Leu-M1, Leu-M2, or Leu-M3 antigens. CSF-1 production following mezerein activation was reduced by incubation in the presence of 10(3) and 10(4) units/ml rIFN gamma. This was confirmed through both biological assays with mouse bone marrow cells and an indirect ELISA. In contrast, the concentration of growth inhibitory activity in conditioned medium was increased by rIFN gamma. A small but significant increase in IL-1 beta concentration in conditioned medium was detected using a sensitive double-antibody ELISA and a radioimmunoassay. The results infer that the functional characteristics of this leukemia cell line are modulated by rIFN gamma in a manner qualitatively similar to that reported for IFN gamma treated normal monocytes.

Quantitation of human interleukin-1 beta with polyclonal antibodies.

Polyclonal antisera to human recombinant interleukin-1 beta have been developed in rabbits and mice. When measured by indirect enzyme-linked immunoassays, the antisera bound rIL-1 beta in a dose-dependent manner but did not bind to rIL-1 alpha or murine rIL-1. Both antisera specifically neutralized thymocyte activation induced by rIL-1 beta or normal monocyte IL-1 and growth inhibition induced by rIL-1 beta. The antiserum specificities led us to examine a double antibody ELISA for quantitating IL-1 beta. The linear portion of the standard curve from an ELISA against rIL-1 beta ranged from 0.5 to 10.0 half-maximal units of [3H]thymidine incorporation in mouse thymocyte cultures. A similar correlation was observed using monocyte derived IL-1 from two sources. The major result of this work was the observation that polyclonal antibodies made against a recombinant molecule also recognized natural IL-1. We suggest that these antisera recognize epitopes unique to IL-1 beta which reside at or near regions of the molecule responsible for biological activity.

Modulation of cell proliferation by human recombinant interleukin-1 and immune interferon.

The growth-modulating effects of recombinant alpha- and beta-forms of human interleukin-1 (IL-1) and interferon-gamma (IFN-gamma) were examined with several human cell lines. Exposure to combinations of IL-1 and IFN-gamma resulted in three categories of cell response. The first was cell lines in which IL-1 stimulated growth and offset the growth inhibitory effects of IFN-gamma. These lines included the lung carcinoma CALU-1 and the colon carcinoma SW-48. The second was some of the cell lines that were refractory to IL-1 and that were inhibited by IFN-gamma alone. These included the cervical carcinoma HeLa, the transformed milk line HBL-100, and the myelogenous leukemia K562. The third group consisted of cells in which growth inhibition by IL-1 and IFN-gamma was additive. These included the mammary carcinomas MCF-7 and MDA-MB-415. The exception to this latter group was ME-180 in which significant additive inhibitory effects could not be demonstrated. IL-1 alone primarily induced a cytostatic effect in growth-inhibited cell lines. The cytolytic effect induced by IFN-gamma was increased in the presence of IL-1. The data support the conclusion that the effects on growth of IL-1 and IFN-gamma are mediated by different mechanisms.

Lymphocyte-activating and growth-inhibitory activities for several sources of native and recombinant interleukin 1.

Several native and recombinant forms of human interleukin-1 (IL-1) and recombinant murine IL-1 were assayed for their ability to inhibit the growth of cell lines established from malignant and nonmalignant human sources. The amount of growth-inhibitory activity was compared to the units of half-maximal [3H]thymidine incorporation in mouse thymocyte cultures exposed to IL-1. Three malignant human mammary cell lines (MCF-7, T47D, and MDA-MB-415) were growth inhibited in the presence of both native and the alpha and beta forms of recombinant human IL-1. MDA-MB-415 was most sensitive. Although most sources of IL-1 showed good correlation between units of activity and percentage of growth inhibition, native IL-1 from Genzyme Corporation induced a cytotoxic effect. Murine IL-1 was less growth inhibitory than the human forms of the monokine. Human embryonic lung (HEL), adult fibroblast (CRL 1445), and transformed milk (HBL-100) lines were not growth inhibited when tested against any IL-1 source. A lung carcinoma (CALU-1) and a colon carcinoma (SW-48) were not inhibited by either the alpha or beta forms of human recombinant IL-1.

Characterization of a colony-stimulating factor produced by the human monocytic leukemia cell line, THP-1.

The human monocytic leukemia cell line, THP-1, acquires macrophage-like characteristics following exposure to mezerein. Serum-free medium conditioned by mezerein-activated cells was observed to contain colony-stimulating factor (CSF) activity in assays with murine bone marrow cultures. Isoelectrofocusing revealed that CSF activity displayed charge heterogeneity and migrated in a pl range of 4.4-5.3. Treatment with neuraminidase did not affect biological activity but did reduce charge heterogeneity. Reisofocusing of neuraminidase-treated CSF revealed a peak of activity at pl 4.9. The active component was shown to be an acidic sialoglycoprotein, resistant to proteolytic cleavage but completely inactivated by 2-mercaptoethanol. This CSF has been purified from THP-1-conditioned serum-free medium by preparative isoelectrofocusing, gel filtration through Sephacryl S-200, ion exchange chromatography on DEAE-Sephacel, neuraminidase treatment, and tris-glycinate polyacrylamide gel electrophoresis (PAGE). Elution from SDS-PAGE revealed a single peak of activity corresponding to an apparent molecular weight of 70,000 daltons. Preliminary characterization of the bone marrow cells in colonies showed that THP-1 cells produced macrophage-specific CSF.

Inhibition of cell proliferation by interleukin-1 derived from monocytic leukemia cells.

Growth inhibitors and interleukin-1 (IL-1) are two biological response modifiers produced by mezerein-treated THP-1 cells maintained in serum-free medium. The activities comigrated with isoelectrofocusing in a pH range of 6.7 to 7.3. Subsequent molecular sieving on an AcA-54 column revealed that a portion of the growth-inhibitory activity for the mammary cell line MCF-7 remained associated with IL-1. IL-1-containing fractions were further analyzed by chromatography with DEAE-Sephacel, phenyl:Sepharose, and concanavalin A:Sepharose. In each instance, IL-1 coeluted with growth-inhibitory activity. IL-1 and growth-inhibitory activities partially purified by sequential isofocusing, AcA-54 chromatography, and DEAE-Sephacel were located in a single region following preparative polyacrylamide gel electrophoresis. Elution, concentration, and analytical polyacrylamide gel electrophoresis of this region resulted in a single band with an apparent molecular weight of 17,000. Stability studies revealed similarities between the IL-1 activity and growth-inhibitory activity in their sensitivity to a variety of physical and chemical treatments. A commercial source of human IL-1 also inhibited the growth of MCF-7 cells. DEAE-purified IL-1 derived from THP-1 cells inhibited the growth of 7 of 11 cell types tested, and all inhibited cell lines were established from malignant sources. Prostaglandin synthesis by MCF-7 cells in response to IL-1 was not responsible for growth inhibition.