Methods of detection of circulating melanoma cells: a comparative overview

Disease dissemination is the major cause of melanoma-related death. A crucial step in the metastatic process is the intravascular invasion and circulation of melanoma cells in the bloodstream with subsequent development of distant micrometastases that is initially clinically undetectable and will eventually progress into clinically apparent metastasis. Therefore, the use of molecular methods to detect circulating melanoma cells may be of value in risk stratification and clinical management of such patients. Herein, we review the currently applied techniques for the detection, isolation, enrichment and further characterization of circulating melanoma cells from peripheral blood samples in melanoma patients. Furthermore, we provide a brief overview of the various molecular markers currently being evaluated as prognostic indicators of melanoma progression.

Insulinlike growth factor-1Ec (MGF) expression in eutopic and ectopic endometrium: characterization of the MGF E-peptide actions in vitro

The transcription of the insulinlike growth factor 1 (igf-1) gene generates three mRNA isoforms, namely IGF-1Ea, IGF-1Eb and IGF-1Ec (or MGF [mechano growth factor]). Herein, we analyzed the expression of IGF-1 isoforms in eutopic and ectopic endometrium (red lesions and endometriotic cysts) of women with endometriosis, and we characterized the actions of a synthetic MGF E-peptide on KLE cells. Our data documented that all three igf-1 gene transcripts are expressed in the stromal cells of the eutopic and ectopic endometrium; however, endometriotic cysts contained significantly lower IGF-1 isoform expression, both at the mRNA and protein level, as was shown using semiquantitative PCR and immunohistochemical methods. In addition, the glandular cells of the eutopic endometrium did not express any of the IGF-1 isoforms; however, the glandular cells of the ectopic endometrium (red lesions) did express the IGF-1Ec at mRNA and protein level. Furthermore, synthetic MGF E-peptide, which comprised the last 24 amino acids of the MGF, stimulated the growth of the KLE cells. Experimental silencing of the type 1 IGF receptor (IGF-1R) and insulin receptor expression of KLE cells (siRNA knock-out methods) did not alter the mitogenic action of the synthetic MGF E-peptide, revealing that MGF E-peptide stimulates the growth of KLE cells via an IGF-1R-independent and insulin receptor-independent mechanism. These data suggest that the IGF-1Ec transcript might generate, apart from mature IGF-1 peptide, another posttranslational bioactive product that may have an important role in endometriosis pathophysiology.

uPA, uPAR and TGFβ₁ expression during early and late post myocardial infarction period in rat myocardium

The expression patterns of transforming growth factor beta 1 (TGFβ₁), urokinase-type plasminogen activator (uPA) and uPA receptor (uPAR) were analysed after artery ligation-induced myocardial infarction (MI) in the rat myocardium. uPA and uPAR expressions were significantly increased both at transcriptional and protein level during early phase post MI period (uPA at 1 hour and uPAR at 24 hours post infarction). TGFβ1 mRNA expression profile revealed a significant increase of TGFβ1 expression from day 4 up to 8 weeks post infarction. These data suggest that the need for an increasing TGFβ₁ bioavailability during the post-infarction period in rat myocardium is achieved in the early post MI period by an increased expression of uPA/uPAR proteolytic system (indirect activation of latent TGFβ₁) and in the late post MI period by direct regulation of TGFβ₁ expression. It is therefore concluded that differential regulation of the TGFβ₁ bioavailability may be a crucial step of the repair mechanisms during the post MI infarction period in the rat myocardium.

Preferential expression of IGF-1Ec (MGF) transcript in cancerous tissues of human prostate: evidence for a novel and autonomous growth factor activity of MGF E peptide in human prostate cancer cells

BACKGROUND

By alternative splicing the IGF-1 gene produces several different transcripts, including IGF-1Ec (MGF). The latter has been mainly associated with muscle regeneration processes.

METHODS

We used immunohistochemistry, RT-PCR, and Western analysis to show the expression status of MGF in prostate tissue and human prostate cell lines (HPrEC, PC-3, and LNCaP) and we studied the exogenous administration of the MGF peptide E on cellular proliferation using trypan blue and MTT assays, before and after the silencing of the IGF-1 receptor and insulin receptor (siRNA methods). The MGF-induced intracellular activation was examined by Western analysis of the active forms of ERK1/2 and Akt.

RESULTS

We documented that MGF is overexpressed in human prostate cancer (PCa) tissues and in human PC-3 and LNCaP cells. Notably, MGF expression was remarkably higher in PCa and prostatic intraepithelial neoplasia (PIN) than normal prostate tissues, while the normal prostate epithelial cells (HPrEC) did not express MGF. Exogenous administration of a synthetic MGF E peptide stimulated the PCa cell growth and activated ERK1/2 phosphorylation without affecting Akt phosphorylation. IGF-1R or insulin receptor (IR) silencing did not affect the mitogenic activity and intracellular signaling of the MGF E peptide in these PCa cells.

CONCLUSIONS

These data suggest the possible implication of MGF E peptide in cancer biology, implying a preferential MGF expression in PCa tissues and cells. This preferential IGF-1 mRNA expression generates the MGF E peptide that possesses mitogenic activity through mechanisms independent of IGF-1R, IR, and hybrid IGF-1R/IR.

Systemic cytokine response following exercise-induced muscle damage in humans

BACKGROUND

Muscle adaptation which occurs following eccentric exercise-induced muscle damage has been associated with an acute inflammatory response. The purpose of this study was to investigate serum interleukin-6 (IL-6), osteoprotegerin and receptor activator of nuclear factor kB ligand (OPG/RANKL) concentrations following muscle damage. We measured changes for several days following muscle damage.

METHODS

Ten healthy young males performed an eccentric exercise protocol using their quadriceps. Blood samples were withdrawn before and at 6 h, 2 days, 5 days and 16 days post-exercise. Functional and clinical measurements were performed before, and on days 1, 2, 5, 8, 12 and 16 post-exercise.

RESULTS

The exercise protocol resulted in muscle damage, indicated by changes in biochemical markers. An increase in IL-6 and OPG, and a decrease in RANKL concentrations were seen at 6 h and on day 2 post-exercise; the OPG:RANKL ratio was increased at 6 h post-exercise (p < 0.05).

CONCLUSIONS

Changes in IL-6 and OPG/RANKL system may represent systemic responses in muscle inflammation and repair processes. However, further studies are needed to elucidate a potential systemic and/or local role of the OPG/RANKL system in skeletal muscle repair.

Expression of IGF-1 isoforms after exercise-induced muscle damage in humans: characterization of the MGF E peptide actions in vitro

Different insulin-like growth factor-1 (IGF-1) isoforms, namely IGF-1Ea, IGF-1Eb and IGF-1Ec (MGF), have been proposed to have various functions in muscle repair and growth. To gain insight into the potentially differential actions of IGF-1 isoforms in the regulation of muscle regeneration, we assessed the time course of their expressions at both mRNA and protein levels after exercise-induced muscle damage in humans. In addition, we characterized mature IGF-1 and synthetic MGF E peptide signalling in C2C12 myoblast-like cells in vitro. Ten healthy male volunteers were subjected to exercise-induced muscle damage and biopsy samples were taken from the exercised muscles before and 6 h, 2, 5 and 16 days post exercise. Muscle damage was documented by specific functional and biochemical responses post exercise. PCR-based analyses of muscle biopsy samples revealed a rapid and transient up-regulation of MGF mRNA expression which was followed by a prolonged increase of IGF-1Ea and IGF-1Eb mRNA expression (p<0.05). Patterns similar to those for mRNA expression were detected for MGF and IGF-1Ea expression at the protein level. The action of synthetic MGF E peptide differed from that of mature IGF-1 since its proliferative effect on C2C12 myoblast-like cells was not blocked by an anti-IGF-1 receptor neutralizing antibody and it did not phosphorylate Akt. Therefore, we conclude that the differential expression profile of IGF-1 isoforms in vivo and the possible IGF-1R - independent MGF E peptide signalling in skeletal muscle-like cells in vitro support the notion that tissue-specific mRNA expression of MGF isoform produces mature IGF-1 and MGF E peptides which possibly act as distinct mitogens in skeletal muscle regeneration.

IGF-1 expression in infarcted myocardium and MGF E peptide actions in rat cardiomyocytes in vitro

Insulinlike growth factor-1 (IGF-1) expression is implicated in myocardial pathophysiology, and two IGF-1 mRNA splice variants have been detected in rodents, IGF-1Ea and mechano-growth factor (MGF). We investigated the expression pattern of IGF-1 gene transcripts in rat myocardium from 1 h up to 8 wks after myocardial infarction induced by left anterior descending coronary artery ligation. In addition, we characterized IGF-1 and MGF E peptide action and their respective signaling in H9C2 myocardial-like cells in vitro. IGF-1Ea and MGF expression were significantly increased, both at transcriptional and translational levels, during the late postinfarction period (4 and 8 wks) in infarcted rat myocardium. Measurements of serum IGF-1 levels in infarcted rats were initially decreased (24 h up to 1 wk) but remained unaltered throughout the late experimental phase (4 to 8 wks) compared with sham-operated rats. Furthermore, specific anti-IGF-1R neutralizing antibody failed to block the synthetic MGF E peptide action, whereas it completely blocked IGF-1 action on the proliferation of H9C2 cells. Moreover, this synthetic MGF E peptide did not activate Akt phosphorylation, whereas it activated ERK1/2 in H9C2 rat myocardial cells. These data support the role of IGF-1 expression in the myocardial repair process and suggest that synthetic MGF E peptide actions may be mediated via an IGF-1R independent pathway in rat myocardial cells, as suggested by our in vitro experiments.

Detection of circulating tumor cells in bladder cancer patients

The methods employed for the detection of circulating bladder cancer cells (CBCs) and their use as a molecular staging tool in clinical settings are thoroughly reviewed. CBC isolation and enrichment methods are discussed according to their advantages and pitfalls along with the clinical data of PCR-based techniques used for CBC detection. In addition, we review the specificity of molecular markers that have been proposed so far for CBC identification, and we comment on the controversial clinical data, proposing laboratory approaches which may improve the clinical significance of CBC detection in bladder cancer.

Detection of circulating tumor cells in prostate cancer patients: methodological pitfalls and clinical relevance

Disseminated malignancy is the major cause of prostate cancer-related mortality. Circulating tumor cells (CTCs) are essential for the establishment of metastasis. Various contemporary and molecular methods using prostate-specific biomarkers have been applied to detect extraprostatic disease that is undetectable by conventional imaging techniques, assessing the risk for disease recurrence after therapy of curative intent. However, the clinical relevance of CTC detection is still controversial. We review current literature regarding molecular methods used for the detection of CTCs in the peripheral blood and bone marrow biopsies of patients with prostate cancer, and we discuss the methodological pitfalls that influence the clinical significance of molecular staging.

Characterization of a rabbit antihuman mechano growth factor (MGF) polyclonal antibody against the last 24 amino acids of the E domain

The human insulin-like growth factor-1 (IGF-1) gene gives rise to multiple, heterogeneous mRNA transcripts by alternative splicing, thus producing different IGF-1 isoforms. The mechano growth factor (MGF) is an IGF-1 isoform that was found to be markedly up-regulated in exercised or damaged muscle. The specific E domain of the MGF splice variant may act as an independent growth factor. The aim of the present study was to characterize a rabbit antihuman MGF polyclonal antibody. New-Zealand rabbits were immunized by injections of a purified synthetic peptide corresponding to the last 24 amino acids of the human C-terminal of the MGF E domain. Western blotting and immunohistochemical techniques were used to characterize the specificity of the polyclonal anti-MGF antiserum. The anti-MGF antiserum was found to recognize the MGF E-peptide and not the common part of the IGF-1 isoforms, i.e. the mature IGF-1 peptide. Furthermore, it specifically bound to the MGF protein in human skeletal and in rat cardiac muscle, apparently due to the considerable homology between the human and rat MGF E-peptide sequences. Immunostaining analysis showed that this polyclonal anti-MGF antibody was able to detect MGF in human muscle and in rat cardiomyocytes and vessels' smooth muscle cells. We conclude that this rabbit polyclonal anti-human/rat MGF antibody could become a valuable tool in the study of IGF-1 isoforms in human and rat tissues.

Experimental hyperthyroidism increases expression of parathyroid hormone-related peptide and type-1 parathyroid hormone receptor in rat ventricular myocardium of the Langendorff ischaemia-reperfusion model

Parathyroid hormone-related peptide (PTHrP) is released under ischaemic conditions and it improves contractile function of stunned myocardium. The actions of PTHrP are mediated primarily by the type 1 parathyroid hormone receptor (PTH.1R), while PTHrP and PTH.1R expression levels are increased in ventricular hypertrophy associated with experimental hyperthyroidism. Since chronic administration of thyroxine (T4) improves postischaemic recovery in isolated heart models subjected to ischaemia-reperfusion stress, we tested the hypothesis that experimentally induced hyperthyroidism is associated with elevated expression of PTHrP and PTH.1R in rat myocardium. Hyperthyroid and control male Wistar rats were subjected to ischaemia-reperfusion stress using the Langendorff technique, and the PTHrP and PTH.1R expression was assessed by relative quantitative reverse transcriptase-polymerase chain reaction, Western blot analysis and immunohistochemistry. In the Langendorff model, the recovery of left ventricular developed pressure at the end of the stablization period and 45 min into the reperfusion period was used to assess the cardioprotective actions of T4 administration. Our data show that hyperthyroid animals had increased tolerance to the ischaemia-reperfusion stress and that this was associated with an increase of PTHrP and PTH.1R expression levels compared with those of control animals. In the control animals, the expression of PTHrP was increased 45 min into the reperfusion phase, while the PTH.1R expression pattern was significantly and gradually decreased throughout the ischaemia and reperfusion phases. In the hyperthyroid animals, the PTHrP and PTH.1R expression pattern was significantly higher throughout the ischaemia and reperfusion phases compared with that of control hearts. Our data suggest that increasing levels of PTHrP and PTH.1R expression can mediate, at least in part, the T4 administration-induced cardioprotection in rat ventricular myocardium.

Implants of type I collagen gel containing MG-63 osteoblast-like cells can act as stable scaffolds stimulating the bone healing process at the sites of the surgically-produced segmental diaphyseal defects in male rabbits

BACKGROUND

Three-dimensional (3-D) type I collagen gel culture systems allow long-term growth of osteoblast-like cells, in vitro. Whether the implantation of 3-D collagen systems can stimulate new bone formation was assessed in male rabbits.

MATERIALS AND METHODS

A 10-mm segmental diaphyseal defect was surgically produced at the left and right limbs of 50 adult male rabbits. The 3-D systems containing MG-63 osteoblast-like cells were implanted at the right-limb defects of all 50 animals. Twenty-five left-limb defects were implanted with 3-D collagen gels containing no MG-63 cells, while the rest were left empty. The bone repair process was serially assessed by radiography for up to 8 weeks and by histological analysis for up to the week 32 post-surgery.

RESULTS

Ninety-four per cent (94%) of the right-limb defects, presented radiographic evidence of complete bone-end bridging within 8 weeks. None of the 50 left-limb defects presented radiographic post-implantation evidence of bone-end bridging. The radiographic evidence of the bone-end bridging was corroborated with histological evidence of new bone formation, while the medullar canals were filled with bone marrow elements.

CONCLUSION

Implants of the 3-D collagen gels containing osteoblast-like cells can be used as stable scaffolds allowing the migration/proliferation of the bone regenerating cells in male rabbits.

Serum testosterone: A potentially adjunct screening test for the assessment of the risk of prostate cancer among men with modestly elevated PSA values (> or =3.0 and <10.0 ng/ml)

Whether serum testosterone (T) can become an adjunct test able to validate the PSA-weighted risk of prostate cancer (PR.CA) in the "grey" diagnostic area (PSA =3.0 to <10.0 ng/ml) was investigated. Seven hundred and eighteen men participated in a prostate screening program using the cutoff PSA value of > or =3.0 ng/ml. PR.CA was found in 26% (22/85) of men with PSA testing within the "grey" diagnostic area and 58% (7/12) with PSA testing > or =10 ng/ml, among the 97 men who agreed to undergo transrectal ultrasound-guided biopsy (TRUS-guided biopsy). The PSA values showed a statistically significant positive association with diagnosis of PR.CA, whereas T and the T/PSA ratio were inversely and significantly related to the disease. In addition, out of 718 subjects, 45 (2.6%) were found to have a T value <2.6 ng/ml and another 78 (10.8%) had "low normal T value" (2.6> or = T <3.0 ng/ml). Of the hypogonadal men, 16 received testosterone enanthate (depot T; 250 mg/ml oily injection, intramuscularly: i.m.; TRT) and three had PSA levels >3.0 ng/mlpost-TRT; one was eventually diagnosed with PR.CA. An empirically-determined cut-off of the T/PSA ratio [>95 ("negative") or <0.95 ("positive")] was found to be optimal with regard to both sensitivity/specificity. This test was "positive" among 95.5% of the PR.CA patients, whereas 81% of biopsies confirmed that non-PR.CA had a "negative" TIPSA ratio, indicating that this ratio can become an adjunct screening test in assessing the risk of PR. CA; in particular, the odds of PR. CA increasing sharply (1/0.08= 12.5 times) with a decrease of the TIPSA ratio by one standard deviation. We conclude that the measurement of the serum T value can become an adjunct test validating further the PSA-weighted risk of PR. CA within the "grey" diagnostic area.

Combination therapy using LHRH and somatostatin analogues plus dexamethasone in androgen ablation refractory prostate cancer patients with bone involvement: a bench to bedside approach

The development of resistance to anticancer therapies is a major hurdle in preventing long-lasting clinical responses to conventional therapies in hormone-refractory prostate cancer. Herein, the molecular evidence documenting that bone metastasis microenvironment survival factors (mainly the paracrine growth hormone-independent, urokinase-type plasminogen activator-mediated increase of IGF-1 and the endocrine production of growth hormone-dependent IGF-1, mainly liver-derived IGF-1 production) produce an epigenetic form of prostate cancer cells that are resistant to proapoptotic therapies is reviewed. Consequently, the authors present the conceptual framework of a novel antibone microenvironment survival factor, mainly an anti-IGF-1 hormonal manipulation for androgen ablation refractory prostate cancer (a combination of conventional androgen ablation therapy [luteinising hormone-releasing hormone agonist-A or orchiectomy]) with dexamethasone plus somatostatin analogue, which yielded durable objective responses and major improvement of bone pain and performance status in stage D3 prostate cancer patients.

Bone-related growth factors and zoledronic acid regulate the PTHrP/PTH.1 receptor bioregulation systems in MG-63 human osteosarcoma cells

Bisphosphonates are known to inhibit osteoclast-mediated bone resorption and osteoblast differentiation and are currently used in the treatment of Paget's disease, osteoporosis, metastatic and osteolytic bone disease and hypercalcaemia of malignancy. The parathyroid hormone-related peptide (PTHrP) and type 1 PTH/PTHrP receptor (PTH.1R) bioregulation systems mediate a wide range of local paracrine/autocrine and intracrine functions in various tissues and modify the actions of pharmaceutical agents on target tissues, both in vivo and in vitro. In addition, bone microenvironment-related growth factors, such as insulin-like growth factor 1 (IGF-1), transforming growth factor beta 1 (TGF beta 1), basic fibroblast growth factor (bFGF) and interleukin 6 (IL-6), can modify the actions of various pharmaceutical agents, including cytotoxic drugs in malignant cell lines. Whether IGF-1, TGF beta 1, bFGF, IL-6 and zoledronic acid affect the expressions of PTHrP and PTH.1R in MG-63 osteoblast-like osteosarcoma cells was investigated in this study. Relative quantitative-PCR (expression at mRNA level) and immunofluorescence analysis (localization of the expression at protein level) were employed to assess PTHrP and PTH.IR expressions. Our data showed that primarily IGF-1, TGF beta 1 and IL-6 (up to 25 ng/ml for 48 h) increased PTHrP mRNA expression and modified its perinuclear localization, while zoledronic acid (up to 100 microM for 48 h) inhibited cell proliferation and suppressed PTHrP expression in the MG-63 osteosarcoma cells. These growth factors were incapable of reversing the zoledronic acid decrease of the expression of PTHrP in the MG-63 cells, suggesting that zoledronic acid and the growth factors affect PTHrP expression via an independent intracellular signal transduction pathway in these cells. However, no appreciable modulation of the PTH.1R expression by IGF-1, TGF beta 1, bFGF, IL-6 or zoledronic acid was detected in MG-63 cells. Therefore, we conclude that PTHrP expression possibly mediates the action of bone microenvironment-related growth factors and of zoledronic acid in MG-63 cells.

Bone microenvironment-related growth factors, zoledronic acid and dexamethasone differentially modulate PTHrP expression in PC-3 prostate cancer cells

Bone metastasis microenvironment-related growth factors such as insulin-like growth factor 1 (IGF-1), transforming growth factor beta 1 (TGF-beta1), basic fibroblast growth factor (bFGF) and interleukin 6 (IL-6) show survival factor activity, thereby inhibiting chemotherapy-induced apoptosis of PC-3 prostate cancer cells in vitro. Recently, zoledronic acid has been shown to induce apoptosis in PC-3 prostate cancer cells while overexpression of parathyroid hormone-related protein (PTHrP) inhibits serum deprivation-induced apoptosis in PC-3 cells. Consequently, we have investigated whether IGF-1, TGF-beta1, bFGF, IL-6, zoledronic acid and/or dexamethasone affect the expression of the PTHrP and type I PTH/PTHrP receptor (PTH.1R) in PC-3 prostate cancer cells using relative quantitative PCR and real-time PCR (expression at mRNA level) and immunocytochemical and immunofluorescence analysis (expression at protein level). Our data show that IGF-1, TGF-beta1, bFGF and IL-6 increase PTHrP mRNA expression and its perinuclear localization, while zoledronic acid (50 muM, 100 muM for 24 h and 48 h) and dexamethasone suppress PTHrP expression in PC-3 cells. We did not detect any appreciable change of the PTH.1R expression due to IGF-1, TGF- beta1, bFGF, IL-6, zoledronic acid or dexamethasone in PC-3 cells. Therefore, it is conceivable that bone metastasis microenvironment-related survival factor/anti-apoptotic activity and zoledronic acid anticancer action/pro-apoptotic activity on PC-3 cells is mediated, at least in part, by differential modulation of PTHrP expression.

Molecular staging by RT-PCR analysis for PSA and PSMA in peripheral blood and bone marrow samples is an independent predictor of time to biochemical failure following radical prostatectomy for clinically localized prostate cancer

Radical prostatectomy should ideally be curative for all patients with clinically localized prostate cancer (PrCa), yet a sizeable proportion of them eventually relapse. We examined in this setting the feasibility of pre-operative risk stratification for early post-operative relapse using reverse transcriptase polymerase chain reaction (RT-PCR) for prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA) transcripts in preoperative bone marrow (BM) biopsies and peripheral blood (PBL) samples. Nested RT-PCR for PSA and PSMA transcripts were performed in RNA from BM biopsies and PBL samples prospectively obtained from 111 men newly diagnosed, by trans-rectal ultrasound (TRUS)-guided biopsy, with clinically localized PrCa and scheduled to undergo radical prostatectomy, according to their respective doctors' recommendation. Molecular analysis for each sample (PBL or BM) was considered positive only if both PSA and PSMA transcripts were detectable. Serial serum PSA level measurements served for biochemical follow-up and detection of biochemical failure (PSA >0.2 ng/ml). PBL and BM RT-PCR molecular staging delineated three groups of patients (a) PBL-BM- (72 patients, 65%), (b) PBL+BM+ (29 patients, 26%), and (c) PBL+BM- (10 patients, 9%). These three groups corresponded to low, high, and intermediate risk for early post-prostatectomy recurrence (median time to biochemical failure of >38, 8, and >28 months, respectively). Multivariate analysis confirmed that molecular staging status was independent predictor of disease-free survival, after adjusting for PSA levels and Gleason score. In clinically localized PrCa, combined PSA/PSMA RT-PCR in PBL and BM is an independent predictor of time to biochemical failure following radical prostatectomy.

Three-dimensional type I collagen cell culture systems for the study of bone pathophysiology

Three-dimensional (3-D) type I collagen cell culture systems composed of reconstituted collagen fibres are able to support short- and long-term growth of various cell types, including cancer cell lines, endothelial cells, endometrial cells, hepatocytes, osteoblasts and fibroblasts and to sustain or even enhance cell differentiation, in vitro. In addition, 3-D culture systems have been successfully used in the investigation of complex biological processes, such as angiogenesis, wound healing, tumour invasion and metastasis. The latter suggested that 3-D culture systems have the potential to simulate cell-cell interactions, which take place in tissues under physiological and pathophysiological conditions. This review focuses on the investigational use of 3-D collagen cell culture systems in bone physiology and the pathophysiology of skeletal metastasis.

Urokinase-Type Plasminogen Activator and Insulin-Like Growth Factor-Binding Protein 3 mRNA Expression in Endometriotic Lesions and Eutopic Endometrium

The peritoneal fluid of women with endometriosis contains an increased insulin-like growth factor 1 (IGF-1) bioavailability, which is produced by limited hydrolysis of urokinase-type plasminogen activator (uPA) on IGF-binding protein 3 (IGFBP-3). Recently, IGF-1 was shown to inhibit apoptosis of endometrial-like cells in vitro, suggesting that a microenvironment of increased IGF-1 bioavailability can optimize the survival of endometrial cells grown ectopically. Here the expression of mRNA of IGFBP-3 and uPA in tissue biopsies from eutopic endometrium and endometriotic lesions obtained at laparoscopy from women with endometriosis have been analyzed, and it is documented that both IGFBP-3 and uPA mRNA expression are increased from 3- to 10-fold in endometriotic lesions versus eutopic endometrium. Consequently, the necessary components (uPA and IGFBP-3 expression) of endocrine/autocrine/paracrine enhancement of local IGF bioavailability mediated by uPA hydrolysis of the IGFBP-3 were present in endometriotic lesions. These data possibly explain the origin of the increased content of uPA activity, IGF-1 bioavailability, and NH(2)-truncated forms of IGFBP-3 in the peritoneal fluid of women with endometriosis.

Molecular evidence-based use of bone resorption-targeted therapy in prostate cancer patients at high risk for bone involvement

BACKGROUND

To improve median survival of patients with prostate cancer that has metastasized to bone, we need to better understand the early events of the metastatic process in skeleton and develop molecular tools capable of detecting the early tumor cell dissemination into bones (micrometastasis stage). However, the initial phase of tumor cell dissemination into the bone marrow is promptly followed by the migration of tumor cells into bone matrix, which is a crucial step that signals the transformation of micrometastasis to macrometastasis stage and clinically evident metastasis. The migration of cancer cells into bone matrix requires the activation of local bone resorption. Such an event contributes to tumor cell hiding/ escaping from high immunologic surveillance of bone marrow cells. Within bone matrix, tumor cells are establishing plethoric cell-cell interactions with bone marrow-residing cells, ensuring their survival and growth. Recently, RT-PCR detections of tumor marker transcripts, such as PSA and PSMA mRNA performed in RNA extracts of peripheral blood nucleated cells and bone marrow biopsy, have enabled the stratification of patients with clinically localized prostate cancer being of high risk for extraprostatic disease and bone involvement. Therefore, it is conceivable that bisphosphonate blockade of bone resorption can inhibit the migration of tumor cells into bone matrix during the early phase of disease dissemination into bone marrow (micrometastasis stage). Consequently, assessment of the efficacy and efficiency of bisphosphonates to arrest the evolution of bone lesions in this particular clinical setting of patients with clinically localized prostate cancer and positive molecular staging status (high risk for bone involvement) is warranted.

Conversion of nested reverse-transcriptase polymerase chain reaction from positive to negative status at peripheral blood during androgen ablation therapy is associated with long progression-free survival in stage D2 prostate cancer patients

BACKGROUND

Nested reverse-transcriptase polymerase chain reaction (nested rt-PCR) for the detection of mRNA of prostate specific antigen (PSA) and prostate specific membrane antigen (PSMA) in peripheral blood samples (PB) and bone marrow biopsies (BM) can assess the extraprostatic growth of prostate cells.

MATERIALS AND METHODS

Nested rt-PCR for PSA and PSMA at PB and BM was performed (a) at diagnosis, (b) after 6 months from the initiation of combined androgen blockade [(CAB); triptorelin 3.75 mg, i.m., q28 days plus flutamide 250 mg, per os, tid] and, (c) at progression to androgen refractory stage in 28 patients with newly-diagnosed stage D2 prostate cancer.

RESULTS

At diagnosis, all patients were found to be rt-PCR positive for PSA and PSMA at BM while 7 (25%) were rt-PCR negative for PSA and PSMA at PB. Nine out of 21 patients with rt-PCR-positive status have converted to rt-PCR-negative status at PB during CAB while they remained rt-PCR-positive at BM. The rt-PCR-negative status at PB during CAB was associated with progression-free survival >12 months (p=0.029). At progression to androgen refractory stage all but 2 patients were rt-PCR-positive at PB for PSA and PSMA, among them 3 who were rt-PCR-negative at diagnosis.

CONCLUSION

Our data suggest that conversion to rt-PCR-negative status at PB for PSA and PSMA during objective clinical response to CAB is associated with long progression-free survival in stage D2 disease.

Repetitive and site-specific molecular staging of prostate cancer using nested reverse transcriptase polymerase chain reaction for prostate specific antigen and prostate specific membrane antigen

We performed repetitive molecular staging using, nested rt-PCR for PSA and PSM at the peripheral blood (PB) and bone marrow (BM) of patients with prostate cancer (Pr.Ca) and benign prostate hyperplasia (BPH) after transrectal ultrasonography-guided biopsy (TRUS-B; 6-9 biopsies/patient), Pr.Ca patients after radical prostatectomy (RP), and Pr.Ca patients with diffuse bony metastases. All BPH patients (N = 20) tested negative at BM. Of the 2 who tested positive at PB 2 weeks after TRUS-B tested negative 8 weeks after TRUS-B. Of the 17 Pr.Ca, 7 (41.2%) tested positive at PB for PSA and PSM 2 weeks after TRUS-B while only 4 (23.5%) of them tested positive at repetitive analysis 8 weeks after TRUS-B. Two (11.8%) of the 17 Pr.Ca patients had positive analysis at BM for PSA and PSM 2 and 8 weeks after TRUS-B. Of 12 Pr.Ca patients with negative pre-operative molecular staging, 7 (58.3%) tested positive at PB for PSA and PSM 2 months post-RP but only 3 (25%) of them re-tested positive 12 months post-RP. Of these 12 Pr.Ca, 4 (33.3%) tested positive at BM for PSA and PSM 2 months post-RP while none re-tested positive 12 months post-RP. All Pr.Ca (N = 20) with diffuse bony lesions tested positive at BM. At PB, 6 of them (30%) tested negative for both PSA and PSM. Our data suggest that nested rt-PCR for PSA and PSM at PB is affected by TRUS-B and RP, while such analysis at BM concerted diffuse bony disease.

Increased insulin-like growth factor 1 activity can rescue KLE endometrial-like cells from apoptosis

BACKGROUND

The peritoneal fluid (PF) of women with endometriosis contains protease(s) activity able to hydrolyze insulin-like growth factor-binding protein 3 (IGFBP-3), increasing the bioavailability of insulin-like growth factor-1 (IGF-1) locally. Therefore, we characterized the effects of IGF-1 on KLE endometrial-like cells in vitro.

MATERIALS AND METHODS

The mitogenic effect of IGF-1 was assessed by the analysis of the DNA content and cell count. Apoptosis was triggered experimentally by the 48 hr exposure of KLE cells to 100 nM of adriamycin in the presence and absence of IGF-1 (50 ng/ml). Adriamycin apoptosis of KLE cells was determined by the number of dead KLE cells using trypan blue exclusion and by the DNA fragmentation on simple agarose gel and flow cytometry of propidium iodide and HOECHST 33342-stained KLE cells using an EPICS 753 pulse cytometer.

RESULTS

IGF-1 stimulated the growth of KLE cells in a dose-dependent manner (optimal dose of 50 ng/ml) and protected KLE cells from adriamycin (100 nM)-induced apoptosis.

CONCLUSIONS

These data suggest that IGF-1 is a survival factor for KLE cells. Conceivably, increased IGF-1 activity in the PF can optimize both the survival and ectopic growth of endometrial cells in the peritoneal cavity.

Three-dimensional type I collagen co-culture systems for the study of cell-cell interactions and treatment response in bone metastases

The available monolayer culture systems for the study of bone metastases constitute a suboptimal simulation of the in vivo pathophysiology of bone metastases, and therefore, do not provide sufficient information to assess the morphologic evidence of bone reaction to cancer cells, the nature of cell-specific mediators of osteolysis and osteoplasia and the response to treatment. Therefore, we have developed a three-dimensional (3-D) type I collagen gel system that allows co-culture of human osteoblasts (MG-63) with cancer cells, such as MCF-7, MDA-MB-231 or ZR-75 breast cancer cells, PC-3 prostate cancer, KLE endometrial cancer cells and Calu-1 lung cancer cells. We used type I collagen purified from rat tail tendons and the 3-D system was prepared by mixing MG-63 cells with type I collagen in 24-well plates. The 3-D system was inoculated with cancer cells and processed with standard cell culture procedures. After 1 week of culture, the matrix gel was fixed with formalin and embedded in paraffin. Serial sections were stained with trichrome Masson stain and modified Masson-Goldner stain, as well as analyzed by in situ hybridization, immunohistochemistry and the TUNEL technique for semi-quantitative detection of apoptotic cell death, assessing the response to adriamycin therapy. The inoculation of PC-3 cells in this collagen matrix produced a blastic reaction, documented by an increased number of MG-63 cells and increased density of type I collagen. The human KLE cells and inoculation of cell-free media produced no reaction, while ZR-75, MCF-7 and Calu-1 cells produced local degradation of the collagen matrix. In situ hybridization revealed the expression of Insulin-like growth factor 1 (IGF-1) and urokinase-type plasminogen activator (uPA) mRNA, while immunohistochemistry detected differential expression of uPA and cathepsin D. Adriamycin induced apoptotic cell death in prostate cancer cells and estrogen receptor negative (ER-) MDA-MB-231 breast cancer cells, while adriamycin did not induce apoptosis but cytostasis in ER+ MCF-7 cells. The adriamycin-induced apoptosis was inhibited by co-culture with osteoblast-like cells (MG-63). We conclude that this 3-D culture system is a useful in vitro model allowing the analysis of local mediators of osteolytic and osteoblastic reactions to bone metastases and treatment response.

Cancer and bone repair mechanism: clinical applications for hormone refractory prostate cancer

It is a long-standing clinical observation that the bone corresponds to the prevalent site for metastatic growth of prostate cancer. In addition, bone metastases of this malignancy produce a potent blastic reaction, in contrast to the overwhelming majority of other osteotropic neoplasms, whose metastases are generally associated with an osteolytic reaction. Osteoblastic metastases represent almost always the first and, frequently, the exclusive site of disease progression to hormone refractory stage, stage D3. Moreover, the number of skeletal metastatic foci is the most powerful independent prognostic factor associated with a limited response to hormone ablation therapy and poor survival of advanced prostate cancer. It is noteworthy that disease progression to hormone refractory stage occurs almost always in osteoblastic metastases. These clinical observations suggested that the osteoblastic reaction is possibly not an innocent bystander of the metastatic prostate tumour growth, simply suffering its consequences, but it may in fact facilitate the efforts of metastatic cells to expand their population. An extensive line of research in the pathophysiology of osteoblastic metastases has established that the local blastic reaction involves the uPA/plasmin/IGF/IGFBP-3/TGFbs bioregulation system which can stimulate both the growth of osteoblasts and prostate cancer cells. Furthermore, we were the first to characterize osteoblast-derived 'survival factors' able to rescue metastatic prostate cancer cells from chemotherapy-induced apoptosis. These data resulted in the development of a novel concept of an anti-survival factor therapy, namely an anti-IGF-1 therapy, which has provided encouraging preliminary data in a phase II clinical trial with terminally-ill hormone/chemotherapy-resistant prostate cancer patients.

Exclusive androgenic effect of dehydroepiandrosterone in sebaceous glands of rat skin

In order to analyze the hormonal effects of dehydroepiandrosterone (DHEA) in skin sebaceous glands, the precursor steroid was administered to ovariectomized (OVX) female Sprague-Dawley rats at a dose of 30 mg applied on the dorsal skin, twice daily, for 3, 6 and 12 months. In a parallel experiment, female OVX rats were treated with DHEA at the same daily percutaneous dose of 30 mg, alone or in combination with the antiandrogen Flutamide or the pure antiestrogen EM-800, for 12 months, in order to determine the androgenic and/or estrogenic components of DHEA action. Treatment of female OVX rats with DHEA resulted in a similar mild to moderate hyperplasia of the sebaceous glands of both dorsal (site of application) and ventral skin, as illustrated by an increase in the number and size of the acini. The above-indicated effects were observed at all time intervals studied, beginning at 3 months of treatment, and they were not further increased after longer term administration of DHEA (for 6 and 12 months). The addition of Flutamide to DHEA treatment completely prevented the DHEA-induced changes in the sebaceous glands, whereas the antiestrogen EM-800 had no effect. The present data indicate an exclusive androgenic stimulatory action of DHEA on the sebaceous glands, thus pointing out the importance of local intracrine DHEA transformation into androgens for skin anatomical integrity and function, while showing that estrogens, if active in rat skin, do not originate from DHEA.

Chemotherapy cytotoxicity of human MCF-7 and MDA-MB 231 breast cancer cells is altered by osteoblast-derived growth factors

One-third of women with breast cancer will develop bone metastases and eventually die from disease progression at these sites. Therefore, we analyzed the ability of human MG-63 osteoblast-like cells (MG-63 cells), MG-63 conditioned media (MG-63 CM), insulin-like growth factor I (IGF-I), and transforming growth factor beta 1 (TGF-beta1) to alter the effects of adriamycin on cell cycle and apoptosis of estrogen receptor negative (ER-) MDA-MB-231 and positive (ER+) MCF-7 breast cancer cells, using cell count, trypan blue exclusion, flow cytometry, detection of DNA fragmentation by simple agarose gel, and the terminal deoxynucleotidyl transferase (TdT)-mediated nick end-labeling method for apoptosis (TUNEL assay). Adriamycin arrested MCF-7 and MDA-MB-231 cells at G2/M phase in the cell cycle and inhibited cell growth. In addition, adriamycin arrested the MCF-7 cells at G1/G0 phase and induced apoptosis of MDA-MB-231 cells. Exogenous IGF-I partially neutralized the adriamycin cytotoxicity/cytostasis of cancer cells. MG-63 CM and TGF-beta1 partially neutralized the adriamycin cytotoxicity of MDA-MB-231 cells but enhanced adriamycin blockade of MCF-7 cells at G1/G0 phase. MG-63 osteoblast-like cells inhibited growth of MCF-7 cells while promoting growth and rescued MDA-MB-231 cells from adriamycin apoptosis in a collagen co-culture system. These data suggest that osteoblast-derived growth factors can alter the chemotherapy response of breast cancer cells. Conceivably, host tissue (bone)-tumor cell interactions can modify the clinical response to chemotherapy in patients with advanced breast cancer.

Osteoblast-derived growth factors enhance adriamycin-cytostasis of MCF-7 human breast cancer cells

Bone only metastasis in patients with estrogen receptor (ER) positive breast cancer reported to have favorable response to chemotherapy, favorable prognosis, and an "indolent" course. Therefore, we assessed the ability of MG-63 osteoblast-like human osteosarcoma cells (MG-63 cells) and MG-63 conditioned media (CM) to influence adriamycin-cytotoxicity of ER-positive MCF-7 human breast cancer cells. Estradiol (E2; 100 nM) increased the distribution at S and G2/M phases in the cell cycle and stimulated the growth of MCF-7 cells. Adriamycin (100 nM) inhibited the growth and arrested the MCF-7 cells supplemented with or without 100 nM of estradiol [(-E2) and (+E2) MCF-7 cultures] at G2/M phase in the cell cycle. In addition, adriamycin (100 nM) increased the distribution at G1/G0 phase in the cell cycle of (+E2) MCF-7 cultures. Adriamycin (100 nM and 10 microM) did not induce apoptosis of MCF-7 cells as assessed by flow cytometry and analysis of DNA fragmentation on simple agarose gel. Exogenous insulin-like growth factor I (IGF I) stimulated while transforming growth factor beta 1 (TGF beta 1) and MG-63 CM inhibited the growth of MCF-7 cells. Furthermore, MG-63 CM and TGF beta 1 enhanced while exogenous IGF I reversed adriamycin (100 nM)-cytostasis of MCF-7 cells. These data suggested that osteoblastic CM contained growth factors, such as TGF beta 1 capable of enhancing adriamycin-cytostasis, in vitro. Conceivably, these osteoblast-derived "enhancers" of chemotherapy-cytostasis can explain the favorable prognosis and "indolent" course of ER-positive breast cancer patients with bone only metastasis.

Effect of dehydroepiandrosterone on vaginal and uterine histomorphology in the rat

Dehydroepiandrosterone (DHEA) applied on the dorsal skin of ovariectomized animals, at the twice daily dose of 30 mg, resulted in a complete reversal of the vaginal atrophy seen 1, 3 and 6 months after ovariectomy, and induced proliferation and mucification of the vaginal epithelium. A similar mucification of the vaginal epithelium related to androgenic action was observed in intact rats treated with DHEA. While treatment of intact rats with DHEA resulted in a significant increase in uterine weight at 1 month, the value of the same parameter decreased by approximately 30% after 3 and 6 months of DHEA administration. In ovariectomized DHEA-treated animals, uterine weight was increased at all time intervals. At histopathological examination, following DHEA administration to intact animals, stimulation was seen in the myometrial layers of the uterus whereas atrophy, involving especially the endometrium, became apparent after 3 and 6 months of treatment. In ovariectomized animals, the endometrium remained atrophic at all time intervals during DHEA treatment and the uterine epithelium thus remained atrophic under DHEA treatment. Examination of the effect of DHEA on the vaginal epithelium indicates that local application of DHEA on the vaginal mucosa is approximately 10-fold more efficient than application at a distant site on the skin. Reversal of the ovariectomy-induced increase in serum LH levels was also observed after DHEA treatment. The present data suggest that DHEA possesses a tissue-specific action, through its local transformation into active estrogens in the vaginal epithelium while the uterine epithelium remains atrophic. In addition, the site of administration of DHEA appears to be a significant factor, at least for its stimulatory effect on the vaginal mucosa.

Osteoblast-derived survival factors protect PC-3 human prostate cancer cells from adriamycin apoptosis

OBJECTIVES

Hormone-independent and cytotoxic drug-resistant tumor growth in osteoblastic metastases defines poor survival in patients with advanced prostate cancer. Therefore, we analyzed the ability of human osteoblast-like cells (MG-63 cells) and MG-63 conditioned media (MG-63 CM) to protect PC-3 human prostate cancer cells from adriamycin cytotoxicity in vitro.

METHODS

Adriamycin cytotoxicity was assessed in MG-63 osteoblast-like and PC-3 prostate cancer monolayer and three-dimensional collagen coculture systems using the DNA content and trypan blue exclusion assays, analysis of indexes of cell cycle by flow cytometry, determination of DNA fragmentation on simple agarose gel and terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay, and immunocytochemistry.

RESULTS

Adriamycin (100 nM) arrested both the PC-3 and MG-63 cells at the G2/M phase in the cell cycle but induced apoptosis only in PC-3 cells, as assessed by flow cytometry, trypan blue exclusion, and agarose gel. Optimal doses of MG-63 CM (50 microg/mL), insulin-like growth factor I (50 ng/mL), and transforming growth factor-beta-1 (25 ng/mL), as determined by DNA content assay, partially neutralized the adriamycin cytotoxicity of PC-3 cells detected by flow cytometry and trypan blue exclusion. In addition, MG-63 cells rescued PC-3 cells from adriamycin apoptosis in the three-dimensional type I collagen gel coculture system, as analyzed by TUNEL assay.

CONCLUSIONS

These data suggest that osteoblast-like cells and osteoblast-derived growth factors can optimize survival of metastatic prostate cancer cells, thereby helping to develop cytotoxic drug-resistant growth in vitro.

Predominant androgenic component in the stimulatory effect of dehydroepiandrosterone on bone mineral density in the rat

In order to assess the relative roles of the androgenic and/or estrogenic components in the stimulatory effect of dehydroepiandrosterone (DHEA) on bone mineral content (BMC) and density (BMD), ovariectomized (OVX) female rats received DHEA administered alone or in combination with the antiandrogen flutamide (FLU) or the antiestrogen EM-800 for 12 months. We also evaluated, for comparison, the effect of estradiol (E2) and dihydrotestosterone (DHT) constantly released by Silastic implants as well as medroxyprogesterone acetate (MPA) released from poly(lactide-co-glycolide) microspheres. Femoral BMD was decreased by 11% 1 year after OVX, but treatment of OVX animals with DHEA increased BMD to a value 8% above that of intact animals. The administration of FLU reversed by 76% the stimulatory effect of DHEA on femoral BMD and completely prevented the stimulatory effect of DHEA on total body and lumbar spine BMD. Similar results were obtained for BMC. On the other hand, treatment with the antiestrogen EM-800 did not reduce the action of DHEA on BMD or BMC. At the doses used, MPA, E2 and DHT increased femoral BMD, but to a lesser degree than observed with DHEA. Bone histomorphometry measurements were also performed. While DHEA treatment partially reversed the marked inhibitory effect of OVX on the tibial trabecular bone volume, the administration of FLU inhibited by 51% (P < 0.01) the stimulatory effect of DHEA on this parameter. The addition of EM-800 to DHEA, on the other hand, increased trabecular bone volume to a value similar to that of intact controls. DHEA administration markedly increased trabecular number while causing a marked decrease in the intertrabecular area. The above stimulatory effect of DHEA on trabecular number was reversed by 54% (P < 0.01) by the administration of FLU, which also reversed by 29% the decrease in intertrabecular area caused by DHEA administration. On the other hand, the addition of EM-800, while further decreasing the intertrabecular space achieved by DHEA treatment, also led to a further increase in trabecular number to a value not significantly different from that of intact control animals, suggesting an additional effect of EM-800 over that achieved by DHEA. Treatment with DHEA caused a 4-fold stimulation of serum alkaline phosphatase, a marker of bone formation, while the urinary excretion of hydroxyproline, a marker of bone resorption, was decreased by DHEA treatment. Treatment with DHEA and DHEA + EM-800 decreased serum cholesterol levels by 22 and 65% respectively, while the other treatments had no significant effect on this parameter. The present data indicate that the potent stimulatory effect of DHEA on bone in the rat is mainly due to the local formation of androgens in bone cells and their intracrine action in osteoblasts.

Effect of twenty-four-week treatment with the antiestrogen EM-800 on estrogen-sensitive parameters in intact and ovariectomized mice

Treatment with the antiestrogen EM-800, at the daily oral dose of 3 microg, 10 microg, 30 microg, or 100 microg for 24 weeks, caused a marked inhibition of uterine and vaginal weight in both intact and ovariectomized mice. Maximal 64% and 41% inhibitions of uterine weight were achieved in intact and ovariectomized animals, respectively. Similar inhibitory effects of EM-800 were observed on vaginal weight with maximal inhibitions of 71% and 35%, in intact and ovariectomized animals, respectively. The pure antiestrogenic activity of EM-800 on the hypothalamo-pituitary-ovarian axis is illustrated by the 76-91% increases in ovarian weight observed in intact animals treated with the 10-100 microg doses of the antiestrogen. Serum 17beta-estradiol was 93% increased at the 100 microg daily dose of EM-800, whereas serum androstenedione, testosterone, and dihydrotestosterone were 141-713% increased over control at the same dose of the antiestrogen. Serum LH was increased by treatment with EM-800 in intact animals, whereas no effect was observed on the elevated gonadotropin levels in ovariectomized animals. At all doses used in intact animals, the antiestrogen caused a complete disappearance of the glandular elements of the mammary gland, the atrophy being comparable with that observed in ovariectomized mice. The mammary gland of EM-800-treated animals was exclusively composed of an atrophied ductal system lined by atrophied epithelial cells with an absence of lobulo-glandular elements. No effect of the compound was observed on the histology of the mammary gland in ovariectomized animals, thus showing the pure antiestrogenic effect of EM-800 on the mammary gland, as shown also for the uterus, vagina, and hypothalamo-pituitary axis. At histopathology, all doses of EM-800 in intact animals led to a moderate to severe uterine and vaginal atrophy. The uterine atrophy affected both the myometrium and the endometrium. Interestingly, the uterine atrophy achieved in intact animals treated with EM-800 was greater than that observed after ovariectomy alone, thus clearly demonstrating the pure antiestrogenic activity of EM-800. The present data show the highly potent and pure antiestrogenic activity of EM-800 on all parameters measured after 6 months of treatment in both intact and ovariectomized mice, a maximal effect being reached at the daily 10 microg dose of the antiestrogen in intact animals.

Almost exclusive androgenic action of dehydroepiandrosterone in the rat mammary gland

To determine the relative role of the androgenic and/or estrogenic components of the action of dehydroepiandrosterone (DHEA) on the histomorphology and structure of the rat mammary gland, ovariectomized (OVX) female animals received DHEA administered alone or in combination with the pure antiandrogen flutamide or the pure antiestrogen EM-800 for 12 months. We have also evaluated the effect of estradiol (E2) and dihydrotestosterone constantly released from SILASTIC brand silicon implants as well as medroxyprogesterone acetate released from poly(lactide-co-glycolide) microspheres. While 1-yr OVX resulted in a severe atrophy of the mammary gland, treatment of OVX animals with DHEA stimulated lobuloalveolar and ductal growth, as well as the secretory activity of the acinar cells, thus resulting in a lobuloalveolar type of development of the mammary gland. The addition of FLU to DHEA almost completely prevented the stimulatory effect observed with DHEA alone, whereas addition of the antiestrogen EM-800 had no significant effect on the action of DHEA on the mammary gland. At the doses used, medroxyprogesterone acetate and dihydrotestosterone also stimulated ductal and alveolar development, although to a lesser degree than that achieved with DHEA. The stimulatory effect of estradiol was mainly expressed on ductal growth with a smaller stimulatory effect on lobuloalveolar development. The above-indicated stimulatory effects on lobuloalveolar development were also reflected in significant increases of the total and parenchymal gland surface areas of the mammary gland. The present study shows that androgens induce a marked lobuloalveolar type of development of the mammary gland in the rat. Moreover, these data indicate the highly predominant or almost exclusive androgenic component in the potent stimulatory action of DHEA on the histomorphology and structure of the rat mammary gland. In fact, blockade of the potential estrogenic component of DHEA action by EM-800 did not affect the stimulatory action of DHEA on mammary gland histomorphology, whereas the antiandrogen FLU almost completely blocked the effect of DHEA.

Morphological changes induced by 6-month treatment of intact and ovariectomized mice with tamoxifen and the pure antiestrogen EM-800

The present study compares the effects of tamoxifen and EM-800, both administered at the oral daily dose of 100 microg for 6 months, on the uterus, vagina, and mammary gland in the mouse at histopathological examination. Treatment of intact animals with EM-800 resulted in uterine and vaginal atrophy even greater than that achieved after ovariectomy, while the developmental growth of the mammary gland was completely blocked and serum LH was increased. In ovariectomized animals, treatment with EM-800 decreased uterine and vaginal wt below the values observed in control ovariectomized mice while no significant change was observed on serum LH, thus indicating the lack of estrogenic activity of EM-800. Tamoxifen, on the other hand, showed a stimulatory estrogenic-like action on the mouse uterus in both intact and ovariectomized animals, thus resulting in moderate to severe endometrial hyperplasia. These morphological changes were accompanied by a marked stimulation of both the estrogenic and androgenic 17beta-hydroxysteroid dehydrogenase as well as 5alpha-reductase uterine activities. The histological atrophic changes observed in the vagina after tamoxifen treatment were less pronounced than those seen after treatment with EM-800. The agonistic estrogen-like action of tamoxifen was also illustrated by the suppression of serum LH levels in ovariectomized animals. A marked stimulation of the ovarian stroma, accompanied by a significant reduction in folliculogenic activity, was observed after EM-800 or tamoxifen administration, although the interstitial ovarian hyperplasia was more pronounced after EM-800 treatment. While both antiestrogens blocked the developmental growth of the mammary gland, EM-800 showed more potent antiestrogenic activity than tamoxifen. The highly potent and specific antiestrogenic activity of EM-800 suggests that this compound could improve the therapy of breast cancer while avoiding the undesirable stimulation of the endometrium.

Comparative effects of 28-day treatment with the new anti-estrogen EM-800 and tamoxifen on estrogen-sensitive parameters in intact mice

Following 28 days of oral administration, in intact mice, the novel non-steroidal anti-estrogen EM-800 was at least 30-fold more potent than tamoxifen in inhibiting uterine weight. Moreover, the maximal inhibitory effect achieved with tamoxifen on uterine weight was only 40% that with EM-800. The pure anti-estrogenic activity of EM-800 on the hypothalamo-pituitary-gonadal axis is illustrated by the increase in ovarian weight, while tamoxifen, due to its estrogenic activity, decreased ovarian weight. EM-800 is 10- to 30-fold more potent than tamoxifen in inhibiting uterine and vaginal estrogen receptors. Since 17beta-hydroxysteroid dehydrogenase (17beta-HSD) is the key enzyme in estradiol formation, the potent inhibitory effect of EM-800 on uterine 17beta-HSD could play an additional role by decreasing the availability of estradiol in the uterine tissue, while tamoxifen, on the contrary, stimulates activity of the enzyme. The atrophic changes in both the endometrial and myometrial layers achieved with EM-800 almost reached those observed 28 days after ovariectomy. EM-800 also resulted in a marked decrease in the number of ovarian developing follicles and corpora lutea, while the number of atretic follicles was increased. Tamoxifen treatment, on the other hand, produced an increase in both the number and crowding of the endometrial glands and a mild atrophy of the myometrial layer. Tamoxifen caused atrophic changes of the vaginal epithelium, especially at the highest doses, though the atrophy was much less pronounced than that following EM-800 treatment or ovariectomy. In addition to being at least 30-fold more potent than tamoxifen in inhibiting uterine weight, the novel anti-estrogen causes atrophy of the endometrium, stimulates the hypothalamo-pituitary-gonadal axis and inhibits uterine 17beta-HSD activity, while tamoxifen exerts opposite and estrogen-like effects on these parameters.

Combined effects of dehydroepiandrosterone and EM-800 on bone mass, serum lipids, and the development of dimethylbenz(A)anthracene-induced mammary carcinoma in the rat

Although treatment with dehydroepiandrosterone (DHEA) and the antiestrogen EM-800 alone decreased dimethylbenz(A)anthracene (DMBA)-induced mammary tumor incidence from 95% to 57% and 38%, respectively, approximately 9 months after DMBA administration, only two tumors developed in the group of animals that received the combination of DHEA and EM-800, and these two tumors disappeared before the end of the experiment (P < 0.01 vs. DHEA or EM-800 alone). Average tumor number per tumor-bearing animal as well as average tumor area per tumor-bearing animal were further decreased in animals that received the combination therapy compared with the effect of each treatment alone (P < 0.01). DHEA induced 6.9% (P < 0.01), 10.6% (P < 0.05), and 8.2% (P < 0.01) increases in bone mineral density of total skeleton, lumbar spine, and femur, respectively. The addition of EM-800 to DHEA did not affect the enhancing effect of DHEA on bone mass. The combination of the two drugs had important inhibitory effects on the urinary excretion of calcium and phosphorus as well as on the urinary hydroxyproline/creatinine ratio. Serum total alkaline phosphatase was stimulated by DHEA. Treatment with EM-800 decreased both serum triglyceride and cholesterol levels, whereas DHEA had an inhibitory effect on serum triglycerides. Although treatment with EM-800 caused a marked atrophy of the mammary gland, DHEA alone reduced lobular hyperplasia seen in aged intact rats while causing an androgen-specific stimulation of the same structures in animals already receiving the antiestrogen EM-800. The combination of DHEA and EM-800 lowered ovarian weight by 24% (P < 0.01) and decreased serum estradiol concentrations to intact control levels, whereas each compound alone had no effect on ovarian weight and stimulated serum estradiol levels by 45% (P < 0.05) and 46% (P < 0.05), respectively. Treatment with EM-800 caused a marked inhibition of uterine and vaginal weight. The present data show the additive inhibitory effects of DHEA and EM-800 on the development of DMBA-induced mammary carcinoma in the rat, thus suggesting the potential benefits of such a combination for the prevention of breast cancer in women while preserving or even increasing bone mass and maintaining a favorable lipid profile.

Stromal fibroblasts are required for PC-3 human prostate cancer cells to produce capillary-like formation of endothelial cells in a three-dimensional co-culture system

The outcome of patients with prostate cancer is largely dependent on the ability of the primary tumor for local invasion, angiogenesis and metastasis. To better understand the cell-cell interactions that participate in prostate cancer neovascularization, we have developed a novel three-dimensional co-culture system. Capillary-like structures were induced in fibrin gel in which collagen gels containing fibroblasts and/or PC-3 human prostate adenocarcinoma cells were sandwiched together. In the presence of collagen-embedded fibroblasts, angiogenesis apparently occurred, while endothelial cells did not survive when only PC-3 cells were embedded in collagen. In contrast, when PC-3 cells were combined with fibroblasts in collagen gel an enhanced formation of capillary-like structure formation was noted, particularly using FGF-2-supplemented medium. In addition, we observed morphological evidence of PC-3 cells and fibroblast invasion into fibrin using this system. Therefore, we conclude that fibroblasts apparently play an important role in angiogenesis and tumor invasion. Furthermore, this novel three-dimensional co-culture is apparently a promising model for studying de novo angiogenesis and tumor invasion in vitro.

Growth factors mediate glucocorticoid receptor function and dexamethasone-induced regression of osteoblastic lesions in hormone refractory prostate cancer

We investigated the ability of important regulators of osteoblast function, such as insulin-like growth factor I (IGF-I), transforming growth factor beta 1 (TGF beta 1), and urokinase-type plasminogen activator (uPA) to act as mediators in cell-cell interactions between osteoblast-like cells and metastatic prostate cancer cells, in vitro. In addition, we assessed whether these growth substances can (a) mediate glucocorticoid receptor (GR) function and (b) be implicated in dexamethasone-induced regression of osteoblastic tumors. Exogenous IGF-I, rat/human uPA, and PA-III (rat)/PC-3 (human) prostate cancer cells conditioned media (CM) stimulated the proliferation of rat (UMR 106 cells) and human (MG-63 cells) osteosarcoma cells. This mitogenic activity was completely neutralized by anti-IGF-I specific antibody. In addition, dexamethasone decreased cell growth, up regulated TGF beta 1 mRNA, and down regulated uPA mRNA expression in prostate cancer cells. Furthermore, it inhibited cell growth by activating latent-TGF beta 1 in osteoblast-like cells. In addition, dexamethasone down regulated the expression of IGF-I mRNA in osteoblast-like cells. Therefore, it is conceivable that uPA, TGF beta 1 and IGF-I mediate at least in part cell-cell interactions and GR function in osteoblastic metastases. Conceivably, regression of the osteoblastic tumors produced by high-dose dexamethasone treatment in hormone-refractory prostate cancer patients is been mediated by differential regulation of growth factors, locally.

Three-dimensional type I collagen gel system containing MG-63 osteoblasts-like cells as a model for studying local bone reaction caused by metastatic cancer cells

We inoculated the KLE human endometrial cancer, MCF-7 and ZR-75 human breast cancer, and PC-3 human prostate cancer cells into three-dimensional type I collagen gel system that contained uniformy dispersed MG-63 osteoblast-like cells. Then, we analyzed the morphological evidence of osteoblasts reaction, local invasion around the inoculated cancer cells and expression of the cathepsin D and urokinase-type plasminogen activator (uPA) around the sites of inoculation using immunocytochemistry. The prostate cancer cells produced morphological evidence of blastic reaction presented as an increased number of MG-63 osteoblasts and increase density of type I collagen around the sites of inoculation with PC-3 cells. The inoculated MCF-7 and ZR-75 cells decreased the density of type I collagen and number of osteoblasts and invaded the collagen gel around the sites of inoculation. The KLE endometrial cancer cells and cell-free media produced no reaction at the inoculation sites suggestive of cancer cell-specific interactions with osteoblasts in this system. The expression of uPA was remarkably higher at the inoculation sites of PC-3 cells as compared with those of the other cancer cells. Cathepsin D expression was higher at the sites of inoculation with KLE, MCF-7 and PC-3 cancer cells. MG-63 osteoblasts contained relatively low expression of uPA and cathepsin D. We conclude that this collagen gel system is a useful model for studying the morphological evidence of local invasion and osteoblasts reaction produced in response to local growth of metastatic cancer cell in vitro.

Plasminogen activator inhibitor 1 messenger RNA expression and molecular evidence for del(7)(q22) in uterine leiomyomas

We analyzed the expression of plasminogen activator inhibitor 1 (PAI-1) in 16 leiomyomas and adjacent myometrium of women who underwent a hysterectomy while in the proliferative (n = 8) and secretory phases (n = 8) of the menstrual cycle. We localized the PAI-1 and its mRNA expression in smooth muscle and vessel endothelial cells of uterine tissues using immunocytochemistry and in situ hybridization. The expression of PAI-1 mRNA was higher in 11 (68.75%) of 16 leiomyomas compared with the adjacent myometrium (leiomyoma/myometrium ratio, 1.4-3.0; mean, 2.045). The leiomyoma:myometrium ratio of PAI-1 mRNA expression did not change during the proliferative (Phase I) and secretory (Phase II) phases of the menstrual cycle. In the remaining five samples, the leiomyoma:myometrium ratio of PAI-1 mRNA expression was close to 1 (0.8-1.2; mean, 0.92). Because the locus of the PAI-1 gene is on chromosome 7q22, we screened for loss of heterozygosity (LOH) in these samples using the PAI-1 marker and D7S471, an anonymous marker 12 cM telomeric to PAI-1. Four of five samples with low leiomyoma:myometrium ratio had LOH for the PAI-1 and/or D7S471 markers. The fifth sample demonstrated a noninformative analysis for these markers but had LOH for the D7S515, D7S666, and D7S518 markers, all centromeric to PAI-1. Because del(7)(q22), associated with a relatively low PAI-1 mRNA expression, can deregulate matrix proteinases and growth factors' activity in leiomyomas, it is conceivable that del(7)(q22) results in heterogeneous leiomyoma biology.

Purification and partial sequencing of the major mitogen for human uterine smooth muscle-like cells in leiomyoma extracts

We purified the major mitogen for human smooth muscle-like cells in leiomyoma extracts by sequential liquid chromatography on (a) carboxymethyl-Sepharose, (b) heparin-Sepharose columns, (c) cartridges of C18 silica, and (d) linear gradient reverse-phase high performance liquid chromatography. The mitogenic activity of the leiomyoma extract throughout purification was tested by tritiated thymidine incorporation and DNA content in NIH/3T3 fibroblasts and KW human smooth muscle-like cells. Purification of the leiomyoma-derived growth factor (LDGF) for KW smooth muscle-like cells confirmed that its partial NH2-terminal amino acid (aa) sequence (1-20 aa) was identical to 113-132 aa of the human cysteine-rich protein (hCRP). A synthetic peptide which was engineered based on the purified aa sequence, stimulated the proliferation and growth of KW cells. An oligonucleotide probe constructed by the cDNA of the hcrp gene that encodes this aa sequence depicted the expression of 1.9-kb LDGF mRNA in leiomyomas and myometrium. The expression of the LDGF mRNA was three to sixfold higher in leiomyomas compared with adjacent myometrium of women harboring leiomyomas by in situ hybridization analysis. These data suggest that LDGF may participate in the pathophysiology of uterine leiomyomas.

Three-dimensional type I collagen gel system for the study of osteoblastic metastases produced by metastatic prostate cancer

We developed a three-dimensional type I collagen gel cell culture system that allows coculturing of human MG-63 osteoblast-like cells and various human cancer cells. Inoculation of human PC-3 metastatic prostate cancer cells into this type I collagen gel containing human MG-63 osteoblast-like cells produced an osteoblastic-like reaction that presented as an increased number of MG-63 cells and increased density of type I collagen around MG-63 cells adjacent to inoculated PC-3 cells by microscope analysis. Under identical experimental conditions, inoculation of cell-free medium, human KLE endometrial adenocarcinoma cells, and Calu-1 lung cancer cells did not produce this blastic-like reaction. In situ hybridization documented the uniform expression of insulin-like growth factor I (IGF-I) and of urokinase-type plasminogen activator (uPA) mRNA in MG-63 and PC-3 cells separately cultured in this substrata. The uniform expression of uPA was also documented by immunocytochemistry using a monoclonal and a polyclonal antihuman uPA antibody. The relative expression of uPA was higher in PC-3 cells than in MG-63, KLE, and Calu-1 cancer cells. We conclude that this novel cell culture system may become a useful model to study the pathophysiology of the osteoblastic reaction in vitro.

Characterization of KW smooth muscle-like human myometrial cells

We characterized the human KW cell line to investigate whether it can serve as a model to study uterine muscle physiology in vitro. KW cells stained (a) positive for vimentin, smooth-muscle-specific alpha actin, tissue-type plasminogen activator (tPA), urokinase-type PA (uPA), uPA receptor, PA inhibitor 1, latent transforming growth factor beta 1 (latent TGF-beta 1) and 17 beta-hydroxysteroid dehydrogenase type I, and (b) negative for desmin, endoglin and cytokeratin 19. Insulin-like growth factor I, epidermal growth factor and platelet-derived growth factor stimulated the DNA synthesis in KW cells in a dose-dependent manner. Therefore, KW cells express a phenotype compatible with human uterine muscle cells. Hence, they can serve as a model to study uterine muscle physiology in vitro.