GPR55 signalling promotes proliferation of pancreatic cancer cells and tumour growth in mice, and its inhibition increases effects of gemcitabine

The life expectancy for pancreatic cancer patients has seen no substantial changes in the last 40 years as very few and mostly just palliative treatments are available. As the five years survival rate remains around 5%, the identification of novel pharmacological targets and development of new therapeutic strategies are urgently needed. Here we demonstrate that inhibition of the G protein-coupled receptor GPR55, using genetic and pharmacological approaches, reduces pancreatic cancer cell growth in vitro and in vivo and we propose that this may represent a novel strategy to inhibit pancreatic ductal adenocarcinoma (PDAC) progression. Specifically, we show that genetic ablation of Gpr55 in the KRASWT/G12D/TP53WT/R172H/Pdx1-Cre+/+ (KPC) mouse model of PDAC significantly prolonged survival. Importantly, KPC mice treated with a combination of the GPR55 antagonist Cannabidiol (CBD) and gemcitabine (GEM, one of the most used drugs to treat PDAC), survived nearly three times longer compared to mice treated with vehicle or GEM alone. Mechanistically, knockdown or pharmacologic inhibition of GPR55 reduced anchorage-dependent and independent growth, cell cycle progression, activation of mitogen-activated protein kinase (MAPK) signalling and protein levels of ribonucleotide reductases in PDAC cells. Consistent with this, genetic ablation of Gpr55 reduced proliferation of tumour cells, MAPK signalling and ribonucleotide reductase M1 levels in KPC mice. Combination of CBD and GEM inhibited tumour cell proliferation in KPC mice and it opposed mechanisms involved in development of resistance to GEM in vitro and in vivo. Finally, we demonstrate that the tumour suppressor p53 regulates GPR55 protein expression through modulation of the microRNA miR34b-3p. Our results demonstrate the important role played by GPR55 downstream of p53 in PDAC progression. Moreover our data indicate that combination of CBD and GEM, both currently approved for medical use, might be tested in clinical trials as a novel promising treatment to improve PDAC patients' outcome.

Hepatocellular Carcinoma with Intracytoplasmic Hyaline Globules

A case of hepatocellular carcinoma with intracytoplasmic hyaline globules is reported. By serological, histochemical, immunofluorescent and electron microscopic studies the authors maintain that in this case intracytoplasmic hyaline globules represent lysosomal structures. According to Von Ardenne's theory, these lysosomal globules appear related to neoplastic cells necrosis.

Features of endothelial dysfunction in umbilical cord vessels of women with gestational diabetes

BACKGROUND AND AIMS

Gestational diabetes (GDM) is associated with increased oxidative stress and overexpression of inflammatory cytokines, both of which might lead to endothelial dysfunction and vascular disease. As such, GDM could be viewed as a sort of ‘short lived’ metabolic syndrome. As umbilical cord vessels represent a suitable model for the study of vascular alterations brought about by GDM, the aim of the present work was to characterize the phenotype of human umbilical vein endothelial cells (HUVECs) chronically exposed to hyperglycaemia and to a pro-inflammatory environment during pregnancy so as to identify molecular modifications of cellular homoeostasis eventually impacting on endothelial dysfunction.

METHODS AND RESULT

Tissue specimens and HUVECs were obtained from umbilical cords of GDMand control women. As compared to controls, GD-HUVEC exhibited enhanced monocyte adhesion and vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1(ICAM-1) expression and exposure on plasma membrane after tumour necrosis factor-alpha(TNF-α) stimulation (Western blot, flow cytometer). As compared to control cells, GD-HUVEC in basal conditions exhibited enhanced monocyte adhesion, nitric oxide synthase (NOS) expression and activity (eNOS Real-Time polymerase chain reaction, Western Blot for eNOS total protein and monomers/dimers ratio, conversion of [3H]-L-arginine in [3H]-L-citrulline), increased O(-)(2)egeneration together with increased NT levels (immunofluorescence) and reduced NO bioavailability(guanosine 3',5'-monophosphate (cGMP) production, EIA). Furthermore, immunohistochemistry revealed increased eNOS and NT immunoreactivity in GD umbilical cords.

CONCLUSION

Endothelial cells exposed in vivo even transiently to hyperglycaemia, oxidative stress and inflammation exhibit durable pro-atherogenic modifications.

Membranous Nectin-4 expression is a risk factor for distant relapse of T1-T2, N0 luminal-A early breast cancer

Nectins are Ca(2+)-independent immunoglobulin-like cell adhesion molecules that compose a family of four members that regulate several cellular activities such as movement, proliferation, survival, differentiation, polarization, and the entry of viruses. Nectin-4 has recently emerged as a metastatis-associated protein in several cancers. Here, we have evaluated the association between the expression of Nectin-4 and the clinical outcome of patients with node-negative, T1/T2 breast cancers.The study group consisted of 197 patients presenting with primary unilateral breast carcinoma (T1/T2), with no evidence of nodal involvement and distant metastases. Nectin-4 protein expression was assessed by immunohistochemistry on tissue microarrays, and the results correlated with the clinical data using Kaplan-Meier curves and multivariate Cox regression analysis. Thirty-four out of 197 tumors (17.3%) exhibited Nectin-4 expression on cell membrane (m-Nectin-4) and 122 out of the 163m-Nectin-4 negative tumors (74.8%) showed high cytoplasmic expression of Nectin-4 (c-Nectin-4(High)). At Kaplan-Meier analysis, m-Nectin-4 positivity was significantly associated with a lower disease-free survival (DFS) and distant relapse-free survival (DRFS) rate in patients with a luminal-A phenotype (P=0.030 and P=0.002, respectively). Multivariate analysis showed that in luminal-A tumors m-Nectin-4 positivity is an independent prognostic factor for DFS (P=0.018) and DRFS (P=0.004), but not for local relapse-free survival (LRFS). On the other hand, c-Nectin-4(High) was significantly associated with higher rates of DFS and LRFS, but not DRFS, in the whole population (P=0.008 and P=0.004, respectively) and in patients with luminal-A tumors (P=0.022 and P=0.018, respectively). In patients with luminal-A tumors, multivariate analysis showed that the prognostic value of c-Nectin-4(Low/Negative) is limited to DFS (P=0.012) and LRFS (P=0.022). We suggest that Nectin-4 represents a prognostic factor and a therapeutic target in luminal-A early stage breast cancer.

Exenatide promotes cognitive enhancement and positive brain metabolic changes in PS1-KI mice but has no effects in 3xTg-AD animals

Recent studies have shown that type 2 diabetes mellitus (T2DM) is a risk factor for cognitive dysfunction or dementia. Insulin resistance is often associated with T2DM and can induce defective insulin signaling in the central nervous system as well as increase the risk of cognitive impairment in the elderly. Glucagone like peptide-1 (GLP-1) is an incretin hormone and, like GLP-1 analogs, stimulates insulin secretion and has been employed in the treatment of T2DM. GLP-1 and GLP-1 analogs also enhance synaptic plasticity and counteract cognitive deficits in mouse models of neuronal dysfunction and/or degeneration. In this study, we investigated the potential neuroprotective effects of long-term treatment with exenatide, a GLP-1 analog, in two animal models of neuronal dysfunction: the PS1-KI and 3xTg-AD mice. We found that exenatide promoted beneficial effects on short- and long-term memory performances in PS1-KI but not in 3xTg-AD animals. In PS1-KI mice, the drug increased brain lactate dehydrogenase activity leading to a net increase in lactate levels, while no effects were observed on mitochondrial respiration. On the contrary, exenatide had no effects on brain metabolism of 3xTg-AD mice. In summary, our data indicate that exenatide improves cognition in PS1-KI mice, an effect likely driven by increasing the brain anaerobic glycolysis rate.

The Trop-2 signalling network in cancer growth

Our findings show that upregulation of a wild-type Trop-2 has a key controlling role in human cancer growth, and that tumour development is quantitatively driven by Trop-2 expression levels. However, little is known about the regulation of expression of the TROP2 gene. Hence, we investigated the TROP2 transcription control network. TROP2 expression was shown to depend on a highly interconnected web of transcription factors: TP63/TP53L, ERG, GRHL1/Get-1 (grainyhead-like epithelial transactivator), HNF1A/TCF-1 (T-cell factor), SPI1/PU.1, WT (Wilms' tumour)1, GLIS2, AIRE (autoimmune regulator), FOXM1 (forkhead box M1) and FOXP3, with HNF4A as the major network hub. TROP2 upregulation was shown to subsequently drive the expression and activation of CREB1 (cyclic AMP-responsive-element binding protein), Jun, NF-κB, Rb, STAT1 and STAT3 through induction of the cyclin D1 and ERK (extracellular signal regulated kinase)/MEK (MAPK/ERK kinase) pathways. Growth-stimulatory signalling through NF-κB, cyclin D1 and ERK was shown to require an intact Trop-2 cytoplasmic tail. Network hubs and interacting partners are co-expressed with Trop-2 in primary human tumours, supporting a role of this signalling network in cancer growth.

An ErbB-3 antibody, MP-RM-1, inhibits tumor growth by blocking ligand-dependent and independent activation of ErbB-3/Akt signaling

The ErbB receptors, such as ErbB-1 and ErbB-2, have been intensely pursued as targets for cancer therapeutics. Although initially efficacious in a subset of patients, drugs targeting these receptors led invariably to resistance, which is often associated with reactivation of the ErbB-3-PI3K-Akt signaling. This may be overcome by an ErbB-3 ligand that abrogates receptor-mediated signaling. Toward this end, we have generated a mouse monoclonal antibody, MP-RM-1, against the extracellular domain (ECD) of ErbB-3 receptor. Assessment of human tumor cell lines, as well as early passage tumor cells revealed that MP-RM-1 effectively inhibited both NRG-1β-dependent and -independent ErbB-3 activation. The antagonizing effect of MP-RM-1 was of non-competitive type, as binding of [(125)I]-labeled NRG-1β to ErbB-3 was not influenced by the antibody. MP-RM-1 treatment led, in most instances, to decreased ErbB-3 expression. In addition, MP-RM-1 was able to inhibit the colony formation ability of tumor cells and tumor growth in two human tumor xenograft nude mouse models. Treatment with the antibody was associated with a decreased ErbB-3 and Akt phosphorylation and ErbB-3 expression in the excised tumor tissue. Collectively, these results indicate that MP-RM-1 has the potential to interfere with signaling by ErbB-3 and reinforce the notion that ErbB-3 could be a key target in cancer-drug design.

Dietary zinc supplementation of 3xTg-AD mice increases BDNF levels and prevents cognitive deficits as well as mitochondrial dysfunction

The overall effect of brain zinc (Zn²⁺) in the progression and development of Alzheimer's disease (AD) is still not completely understood. Although an excess of Zn²⁺ can exacerbate the pathological features of AD, a deficit of Zn²⁺ intake has also been shown to increase the volume of amyloid plaques in AD transgenic mice. In this study, we investigated the effect of dietary Zn²⁺ supplementation (30 p.p.m.) in a transgenic mouse model of AD, the 3xTg-AD, that expresses both β amyloid (Aβ)- and tau-dependent pathology. We found that Zn²⁺ supplementation greatly delays hippocampal-dependent memory deficits and strongly reduces both Aβ and tau pathology in the hippocampus. We also evaluated signs of mitochondrial dysfunction and found that Zn²⁺ supplementation prevents the age-dependent respiratory deficits we observed in untreated 3xTg-AD mice. Finally, we found that Zn²⁺ supplementation greatly increases the levels of brain-derived neurotrophic factor (BDNF) of treated 3xTg-AD mice. In summary, our data support the idea that controlling the brain Zn²⁺ homeostasis may be beneficial in the treatment of AD.

p53 Status Splits Triple-Negative Breast Cancers in Subgroups with Distinct Predictive and Prognostic Potential Value

Background: Triple-negative breast cancers largely encompass basal-like breast cancers, which demonstrate an aggressive clinical behaviour and poor prognosis. However, triple-negatives also include normal breast-like cancers, as identified by gene expression profiling, which have a better prognosis than basal-like cancers, but do not respond as well to neoadjuvant chemotherapy. Thus, a clear-cut distinction between the two subgroups is urgently needed. p53 is heterogeneously expressed in triple-negative cases, suggesting association to subgroups with diverse biological profiles. Hence, we comparatively analyzed p53 expression in triple-negative breast cancers from two independent case series.Material and Methods: Two independent breast tumor case series (633 cases from Ferrara University, Italy and 1076 cases from Nottingham University, UK) were analysed. Applying non-hierarchical algorithms, we have previously identified four breast tumor clusters, that possess markedly different prognosis: cluster [1], characterized by high values of ER/PR (good prognosis); cluster [2], with intermediate / heterogeneous ER/PR values (good prognosis); cluster [3], with low-to-nil ER (bad prognosis) and cluster [4] with low-to-nil PR and high HER2 values (bad prognosis) (Clin Cancer Res 2006;12:781-90). p53 expression in triple-negative cases belonging to the different clusters was analyzed.Results: p53 protein expression sharply subdivided the triple-negative Ferrara cases into two distinct subsets, that were tightly associated to clusters [2] or [3], respectively. Low-to-nil p53 levels were only observed in cluster [2] while overexpression of p53 was only seen in cluster [3].The triple-negative tumors of the Nottingham dataset were comparatively evaluated. Consistently with the data of the Ferrara case series, p53 similarly split this case series in p53-overexpressing and p53 low-to-nil triple-negative cases. p53 expression was associated with shorter relapse-free (Figure 2) and overall survival.Discussion: Our findings indicate that p53 expression can split triple negative breast cancers into sharply distinct subgroups, with critically different prognosis and prediction of drug response potential.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2018.

Selective killing of human cancer cells by targeting a fusion mRNA between CYCLIN D1 and TROP2

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Background: Trop-2 is a calcium signal transducer and a stem cell marker. Trop-2 is widely overexpressed by human cancers and stimulates their growth. A TROP2 mRNA was isolated as post-transcriptionally joined to CYCLIN D1 transcripts, suggesting this as one of the transforming mechanisms of TROP2. Methods: In vitro cell growth assays were utilized to assess the cell growth stimulatory capacity of the chimeric mRNA. Colony assays for growth in soft agarose and tumorigenicity assays in nude mice were utilized to assess for the transforming capacity of the fusion transcript. siRNA constructs were utilized for the stably shut-down of the expression of the CYCLIN D1-TROP2 mRNA. Results: The chimeric mRNA transforms primary cells in vitro and induces aggressive tumor growth in vivo in cooperation with activated RAS. The CYCLIN D1-TROP2 mRNA is expressed by a large fraction of human ovarian, endometrial and gastro-intestinal tumors. The chimera is coexpressed with activated RAS in a subset of tumors, consistent with a cooperative transforming activity. The chimeric mRNA is a bicistronic transcript that independently translates wild type Cyclin D1 and Trop-2 proteins, i.e. it does not generate chimeric, oncogenic proteins. On the other hand, joining to the stable TROP2 mRNA leads to a higher CYCLIN D1 mRNA stability, with inappropriate persistence during the cell cycle and acquisition of transforming capacity. As essentially no normal tissues express the chimeric mRNA, we targeted it for destruction in cancer cells with stably expressed siRNA constructs. Specific targeting led to essential annnihilation of the CYCLIN D1-TROP2 mRNA, in the absence of off-target effects. Silencing of the chimeric mRNA blocked the growth of expressing breast cancer cells. Conclusions: Our findings demonstrate a novel, widespread oncogenic mechanism in human cancers, and open novel avenues for mRNA-targeted anti-cancer therapies. Acknowledgments This work was supported by the the Fondazione of the Cassa di Risparmio della Provincia di Chieti, the Association for the Application of Biotechnology in Oncology (ABO and ABO Project S.p.A., grant no. VE01D0019) and the Marie Curie Transfer of Knowledge Fellowship, contract number 014541.

No significant financial relationships to disclose.

Patterns of K-ras mutation in colorectal carcinomas from Iran and Italy (a Gruppo Oncologico dell'Italia Meridionale study): influence of microsatellite instability status and country of origin

BACKGROUND

K-ras mutations are a key step in colorectal cancer progression. Such mutations have been widely studied in case series from Western countries but there are few data on the rate and spectrum of mutations in tumors from countries where the epidemiological features of the disease are different.

PATIENTS AND METHODS

Tumor samples from 182 Iranian colorectal cancer patients (170 sporadic cases and 12 HNPCC cases) were screened for K-ras mutations at codons 12, 13 and 61 by sequencing analysis. The cases were also characterized for microsatellite instability at mononucleotide repeats by PCR and fragment analysis, and classified according to microsatellite instability status. The frequency and the spectrum of K-ras mutations were compared with those observed in a series of colorectal cancer patients from Italy.

RESULTS

K-ras mutations were observed in 68/182 (37.4%) cases. Mutation frequencies were similar in HNPCC-associated, sporadic MSI-H and sporadic microsatellite-stable (MSS) tumors. However, the G13D substitution was more frequent in HNPCC (3/4, 75%) and sporadic MSI-H (7/11, 63.6%) tumors compared to sporadic MSS tumors (11/53, 20.4%) (P <0.01). Comparison of mutations in the two series from Iran and Italy showed a significantly higher frequency of G13D among Italian patients.

CONCLUSIONS

While the frequency of K-ras mutations could be similar, the mutational spectrum could be differentially influenced by genetic and environmental factors.

TROP2 is a major determinant of growth and metastatic spreading of human cancer

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Background: The TROP2 gene encodes a transmembrane calcium signal transducer, involved in the regulation of cell- cell adhesion. Methods: To identify the role of Trop-2 in transformed cells, we studied its expression pattern and function by DNA array and SAGE analysis, Northern and Western blotting, flow cytometry, confocal microscopy and IHC in experimental systems and in man. Overexpression or down-regulation of Trop-2 and directed mutagenesis were used to identify its role in tumor growth and metastasis in vivo. Results: DNA microarray, EST, SAGE, RT-PCR and Northern blot analysis of human tumors revealed expression of the TROP2 gene in most cancers. IHC analysis of human tumors (1755 cases) revealed a corresponding overexpression of Trop-2 protein. Trop-2 potently stimulated the growth of tumor cells, whereas TROP2 siRNA inhibited it. Deletion of the cytoplasmic region of Trop-2 abolished the growth stimulatory capacity, as did mutagenesis of the S303 PKC phosphorylation site. Proteomic analysis showed that multiple PKC isoforms partecipate to the Trop-2 signaling network. In vivo imaging showed dynamic colocalization of PKCs and Trop-2 in vivo in membrane ruffles and podosomes. DN PKCs and siRNA abolished Trop-2-induced growth. Strikingly, comparative global gene expression analysis revealed that TROP2 was the only gene up-regulated across different metastatic models, tumor types and animal species. IHC analysis revealed a dramatic up-regulation in metastases from colon, stomach, breast and ovary tumors in man. To assess if Trop-2 may play a causal role in metastatic spreading, TROP2-transfected KM12SM colon cancer cells were orthotopically injected in nude mice. TROP2-overexpressing transfectants demonstrated increased metastatic potential to the liver. Deletion of the HIKE domain of Trop-2 severely diminished, whereas that of the whole cytoplasmic region vastly increased metastatic diffusion, indicating the existence of both metastatic enhancers and silencers in the Trop-2 cytoplasmic tail. Conclusions: Our findings demonstrate that Trop-2 is a novel, widespread, stimulator of human cancer growth and a unique marker and causal factor of metastatic cancer, and candidate Trop-2 as a target of novel diagnostic and therapeutic procedures.

No significant financial relationships to disclose.

Axillary lymph node nanometastases are prognostic factors for metastatic relapse in breast cancer patients

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Background: Early breast cancer presents with a remarkable and largely unaccounted for heterogeneity of outcomes. Undetected, microscopic lymph node tumor deposits may account for a significant fraction of this prognostic diversity. Thus, we systematically evaluated the presence of lymph node tumor cell deposits <0.2 mm in diameter [pN0(i+), nanometastases], and analysed their prognostic impact. Methods: Seven hundred and two single institution, consecutive patients with 8 years of median follow-up were studied. To maximize the chances of detecting micro and nanometastases, whole-axilla dissections were analysed. pN0 cases were systematically reevaluated by step sectioning and anti-cytokeratin immunohistochemical analysis of 6676 corresponding dissected lymph nodes. The risk of first adverse events and of distant relapse of bona fide pN0 patients was compared with that of pN0(i+), pN1mi and pN1 cases. Crude cumulative incidence (CCI) curves were used to estimate the cumulative probability of occurrence of adverse events. CCI curves were compared by the Gray’s test. A proportional sub distribution hazard (SDH) regression model was utilized to assess the difference among CCI curves of pN0(i+) versus pN0(i-), and of pN1mi versus pN0(i+). Competing risks were accounted for and regression models were adjusted for established breast cancer prognostic factors, i.e. grading, pathological T stage and age. Proportional SDH assumptions were checked using Schoenfeld-type residuals. Results: A pN0(i+) status was shown to be a strong risk factor for event-free survival (P<0.0005) and for metastatic relapse in both univariate and multivariate analyses accounting for competing risks and adjusted for grading, pathological T stage and age. Conclusions: Our findings demonstrate that nanometastases are an important risk factor in breast cancer. These results support the inclusion of procedures for nanometastasis detection in TNM pathological staging.

No significant financial relationships to disclose.

Intrathymic deficient expansion of T cell precursors in Down syndrome

To correlate the intrinsic cellular immunodeficiency, which is a major cause of increased susceptibility to polytopic infections in Down syndrome (DS) patients, with the histologic abnormalities observed in the thymus of these patients, we have studied thymus fragments and thymocyte cell suspensions from 15 non-institutionalized DS subjects. Comparing to the control age-matched samples, a reduced thymic cortex and a distinct depletion of CD1-positive (+) cells was observed by immuno-histologic examination. The phenotypic analysis of unselected thymocytes showed a significant reduction of CD3+, CD1+, CD4+, and CD8+ cells. When the total thymocyte population was separated into 10 fractions, using a continuous Percoll density gradient, a difference in cell distribution was observed. DS thymuses are almost devoid of high-density thymocytes (fractions 6-9) while more than 75% of the cells were recovered in the lightest 3 fractions (Frs). In addition, these thymuses were characterized by a marked depletion of CD1+ cells and by a conspicuous reduction of CD3+ cells normally present in the high-density Frs. On the other hand, the lightest 3 Frs of DS subjects were enriched in low-density CD1+ cells. Although enriched in these cells, normally characterized by a high mitotic activity, Fr1 DS thymocytes showed a reduced spontaneous proliferative capacity. When the expression of T cell receptor alpha- and beta-subunits was studied, the percentages of cells stained with anti-alpha and anti-beta antisera were found to be reduced in DS unfractionated thymocytes. The reduced number of high-density CD1+ thymocytes associated with a reduced spontaneous proliferative activity of low-density CD1+ thymocytes suggests that in DS thymuses there is a deficient expansion of immature T cells, resulting in a reduction of the various thymocyte subpopulations, including the thymocyte pool which differentiates into functionally mature T cells expressing the alpha-beta T cell receptor.

Morphological and immunohistochemical study of Down syndrome thymus

The incidence and severity of various histologic changes were studied in the thymuses from 35 Down syndrome (DS) patients. Variable histologic alterations up to fibrotic involution of the gland were found. In addition, immunohistochemical investigation showed a reduction or absence of interdigitating reticulum cells roughly correlated with the severity of morphologic changes. The complex architectural and cellular thymic alterations, concerning both cortical and medullary microenvironment, could be correlated with the imbalances of immunity in DS patients.

Quercetin and tamoxifen sensitize human melanoma cells to hyperthermia

Hyperthermia produces regression of human cancer. Because hyperthermia has produced only limited results, attention has focused on searching for substances able to sensitize tumour cells to the effects of hyperthermia. The flavonoid quercetin has been reported to be a hyperthermic sensitizer in ovarian and uterine cervical tumours and in leukaemia. Quercetin and tamoxifen inhibit melanoma cell growth. We therefore investigated whether quercetin and tamoxifen can sensitize M10, M14 and MNT1 human melanoma cells to hyperthermia. We observed that both quercetin and tamoxifen synergize with hyperthermia (42.5 degrees C) in reducing the clonogenic activity of M14 and MNT1 and in inducing apoptotic cell death in all three cell lines. As revealed by flow cytometric and Northern blot analyses, quercetin and tamoxifen reduced heat shock protein-70 expression at both protein and mRNA levels. Our results suggest that quercetin and tamoxifen can be usefully combined with hyperthermia in the therapy of recurrent and/or metastatic melanoma.

Expression of hMSH2 and hMLH1 proteins of the human DNA mismatch repair system in ameloblastoma

The human DNA mismatch repair (hMMR) system plays an important role in reducing mutation and maintaining genomic stability. The MMR system in human cells is composed of at least six genes (hMSH2, hMLH1, hMSH3, hPMS1, hPMS2 and GTBP/hMSH6). In particular, hMSH2 and hMLH1 are expressed in human cells that are undergoing rapid renewal; their reduced expression has been reported in several tumors. We examined the protein expression pattern of hMSH2 and hMLH1 by immunohistochemistry in 25 ameloblastomas. All ameloblastomas expressed hMSH2 and hMLH1 proteins in the outer layer of epithelial cells. The localization of the staining was exclusively nuclear. These data suggest that the development and progression of these tumors do not depend on a defect in the hMMR system.

Flavonoids apigenin and quercetin inhibit melanoma growth and metastatic potential

Flavonoids are a class of polyphenolic compounds widely distributed in the plant kingdom, which display a variety of biological activities, including chemoprevention and tumor growth inhibition. Our aim was to investigate the effects of several polyphenols on the growth and metastatic potential of B16-BL6 melanoma cells in vivo. Intraperitoneal administration of quercetin, apigenin, (-)-epigallocathechin-3-gallate (EGCG), resveratrol, and the anti-estrogen tamoxifen, at the time of i.m. injection of B16-BL6 cells into syngeneic mice, resulted in a significant, dose-dependent delay of tumor growth, without toxicity. The relative descending order of potency was EGCG > apigenin = quercetin = tamoxifen > resveratrol > control. Furthermore, polyphenols significantly potentiated the inhibitory effect of a non-toxic dose of cisplatin. When tested for the ability to inhibit lung colonization, quercetin, apigenin, and tamoxifen (but not EGCG or resveratrol) significantly decreased the number of B16-BL6 colonies in the lungs in a dose-dependent manner, with quercetin and apigenin being more effective than tamoxifen. Interestingly, quercetin, apigenin, and tamoxifen (but not EGCG or resveratrol) significantly decreased the invasion of B16-BL6 cells in vitro, with quercetin and apigenin being more effective than tamoxifen. This suggests that anti-invasive activity is one of the mechanisms underlying inhibition of lung colonization by quercetin and apigenin. In conclusion, quercetin and apigenin inhibit melanoma growth and invasive and metastatic potential; therefore, they may constitute a valuable tool in the combination therapy of metastatic melanoma.

Flavonoids apigenin and quercetin inhibit melanoma growth and metastatic potential

Flavonoids are a class of polyphenolic compounds widely distributed in the plant kingdom, which display a variety of biological activities, including chemoprevention and tumor growth inhibition. Our aim was to investigate the effects of several polyphenols on the growth and metastatic potential of B16-BL6 melanoma cells in vivo. Intraperitoneal administration of quercetin, apigenin, (-)-epigallocathechin-3-gallate (EGCG), resveratrol, and the anti-estrogen tamoxifen, at the time of i.m. injection of B16-BL6 cells into syngeneic mice, resulted in a significant, dose-dependent delay of tumor growth, without toxicity. The relative descending order of potency was EGCG > apigenin = quercetin = tamoxifen > resveratrol > control. Furthermore, polyphenols significantly potentiated the inhibitory effect of a non-toxic dose of cisplatin. When tested for the ability to inhibit lung colonization, quercetin, apigenin, and tamoxifen (but not EGCG or resveratrol) significantly decreased the number of B16-BL6 colonies in the lungs in a dose-dependent manner, with quercetin and apigenin being more effective than tamoxifen. Interestingly, quercetin, apigenin, and tamoxifen (but not EGCG or resveratrol) significantly decreased the invasion of B16-BL6 cells in vitro, with quercetin and apigenin being more effective than tamoxifen. This suggests that anti-invasive activity is one of the mechanisms underlying inhibition of lung colonization by quercetin and apigenin. In conclusion, quercetin and apigenin inhibit melanoma growth and invasive and metastatic potential; therefore, they may constitute a valuable tool in the combination therapy of metastatic melanoma.

Flavonoids apigenin and quercetin inhibit melanoma growth and metastatic potential

Flavonoids are a class of polyphenolic compounds widely distributed in the plant kingdom, which display a variety of biological activities, including chemoprevention and tumor growth inhibition. Our aim was to investigate the effects of several polyphenols on the growth and metastatic potential of B16-BL6 melanoma cells in vivo. Intraperitoneal administration of quercetin, apigenin, (-)-epigallocathechin-3-gallate (EGCG), resveratrol, and the anti-estrogen tamoxifen, at the time of i.m. injection of B16-BL6 cells into syngeneic mice, resulted in a significant, dose-dependent delay of tumor growth, without toxicity. The relative descending order of potency was EGCG > apigenin = quercetin = tamoxifen > resveratrol > control. Furthermore, polyphenols significantly potentiated the inhibitory effect of a non-toxic dose of cisplatin. When tested for the ability to inhibit lung colonization, quercetin, apigenin, and tamoxifen (but not EGCG or resveratrol) significantly decreased the number of B16-BL6 colonies in the lungs in a dose-dependent manner, with quercetin and apigenin being more effective than tamoxifen. Interestingly, quercetin, apigenin, and tamoxifen (but not EGCG or resveratrol) significantly decreased the invasion of B16-BL6 cells in vitro, with quercetin and apigenin being more effective than tamoxifen. This suggests that anti-invasive activity is one of the mechanisms underlying inhibition of lung colonization by quercetin and apigenin. In conclusion, quercetin and apigenin inhibit melanoma growth and invasive and metastatic potential; therefore, they may constitute a valuable tool in the combination therapy of metastatic melanoma.

Quercetin inhibits p21-RAS expression in human colon cancer cell lines and in primary colorectal tumors

Immunocytochemical studies have revealed that 10 microM quercetin reduced the steady state levels of p21-ras proteins in both colon cancer cell lines and primary colorectal tumors. These findings were confirmed by Western blot and flow cytometric analysis showing that the inhibition of p21-ras expression by quercetin was time- and concentration-dependent. Twenty-four-hour treatment with 10 microM quercetin reduced p21-ras levels to about 50% of control values. Quercetin was similarly effective in inhibiting the expression of K-, H-, and N-ras proteins. Moreover, the effect of quercetin on ras oncogene expression was not dependent on the cell cycle position of colon cancer cells and appeared to be specific and not merely a consequence of overall inhibition of protein synthesis. Northern blot analysis revealed that quercetin produced in colon cancer cells an early (30 min) reduction of the steady state levels of K-, H-, and N-ras mRNAs. This reduction was also present after 6 hr of flavonoid treatment. These effects of quercetin suggest a possible chemopreventive role for this compound in colorectal carcinogenesis.

Quercetin inhibits p21-RAS expression in human colon cancer cell lines and in primary colorectal tumors

Immunocytochemical studies have revealed that 10 microM quercetin reduced the steady state levels of p21-ras proteins in both colon cancer cell lines and primary colorectal tumors. These findings were confirmed by Western blot and flow cytometric analysis showing that the inhibition of p21-ras expression by quercetin was time- and concentration-dependent. Twenty-four-hour treatment with 10 microM quercetin reduced p21-ras levels to about 50% of control values. Quercetin was similarly effective in inhibiting the expression of K-, H-, and N-ras proteins. Moreover, the effect of quercetin on ras oncogene expression was not dependent on the cell cycle position of colon cancer cells and appeared to be specific and not merely a consequence of overall inhibition of protein synthesis. Northern blot analysis revealed that quercetin produced in colon cancer cells an early (30 min) reduction of the steady state levels of K-, H-, and N-ras mRNAs. This reduction was also present after 6 hr of flavonoid treatment. These effects of quercetin suggest a possible chemopreventive role for this compound in colorectal carcinogenesis.

Morphometric prognostic index in breast cancer

OBJECTIVE

To assess the ability of the morphometric prognostic index (MPI) in predicting clinical outcome in a group of breast cancer patients with short-term follow-up and to assess the relationship between MPI and other prognosticators.

STUDY DESIGN

The study group consisted of 63 cases of breast cancer. Follow-up data were available for 48 patients. MPI values were calculated, and degree of nuclear and tubular differentiation was investigated in each tumor. S-phase fraction (SPF), estrogen and progesterone receptors were also studied.

RESULTS

The group of patients with MPI values < 0.60 had percent values of disease-free survival significantly higher than did those with MPI values > or = 0.60. Furthermore, significant direct correlations were found between MPI and degree of nuclear atypia and between MPI and SPF. Significant inverse relationships were found between MPI and tumor progesterone receptor levels and between MPI and degree of histologic tubular differentiation.

CONCLUSION

The validity of MPI as a prognosticator in breast cancer was confirmed, even in a limited number of patients observed in short-term follow-up. MPI seems to be a reliable and economical prognosticator in selecting breast cancer patients for adjuvant chemotherapy.

Growth-inhibitory effect of tamoxifen and quercetin and presence of type II estrogen binding sites in human laryngeal cancer cell lines and primary laryngeal tumors

Quercetin and tamoxifen, in a range of concentrations between 0.01 and 5 microM, exert a dose-dependent inhibition on the anchorage-dependent and anchorage-independent cell growth of Hep2 and CO-K3 laryngeal cancer cell lines. Cell cycle analysis revealed that the growth-inhibitory effect was associated with a block of the cells at the G2/M checkpoint of the cell cycle followed by DNA fragmentation. This suggests that the failure of cells to proceed through the G2/M checkpoint can be a trigger for apoptosis. The induction of apoptosis by quercetin and tamoxifen was confirmed immunocytochemically by the in situ nick end labeling (TUNEL) reaction. These compounds also exerted a dose-dependent growth-inhibitory effect on primary tumor cells, as assessed by colony-forming assay and bromodeoxyuridine labeling. Laryngeal cancer cell lines and primary tumor cells expressed Type II estrogen binding sites (Type II EBS) with binding characteristics similar to those of Type II EBS in other tumor cells. Since the affinities of quercetin and tamoxifen for Type II EBS were correlated with their growth-inhibitory potential while ipriflavone neither interacted with these sites nor inhibited cell growth, the possibility exists that the action of these compounds is mediated, at least in part, by the interaction with Type II EBS. In conclusion, our data indicate that quercetin and tamoxifen could be potentially useful in laryngeal cancer treatment.

IL-10 synergizes with dexamethasone in inhibiting human T cell proliferation

We have evaluated the effects of dexamethasone (Dex) alone or in combination with interleukin (IL)-10 or transforming growth factor-beta 1 (TGF-beta 1) on human T cell proliferation. Both IL-10 and TGF-beta 1 significantly decreased the Dex concentration needed to inhibit T cell proliferation by 50% (IC50). Dex in combination with IL-10 completely inhibited T cell proliferation, even when IL-10 alone was ineffective, as in the case of phytohemagglutinin-induced T cell proliferation. The evaluation of the results according to the isobole method displayed a potent synergistic activity between Dex and IL-10, whereas the combination of Dex with TGF-beta 1 was additive. IL-10, but not TGF-beta 1, enhanced the inhibitory effect of Dex on IL-2 production. IL-2 and IL-4 only partly antagonized the antiproliferative effect of the combinations. IL-4 was as effective as IL-2 in antagonizing the combination of Dex with TGF-beta 1, but significantly less effective against the combination of Dex with IL-10. IL-10 and TGF-beta 1 are thus able to potentiate the Dex inhibitory effect on T cell proliferation and could be regarded as potential agents for future immunosuppressive protocols.

Prognostic significance of methyl-p-hydroxy-phenyllactate-esterase activity in laryngeal squamous cell carcinoma

We assayed methyl-p-hydroxyphenyllactate esterase (MeHPLAase) activity in 63 cases of primary laryngeal squamous cell carcinoma. MeHPLAase activity did not show any correlation with oestrogen, progesterone and epidermal growth factor (EGF) receptor levels. No significant relationship was found between MeHPLAase activity and age, sex, tumour site, T classification, stage of disease and EGFR status, whereas a significant inverse relationship was found between enzymatic activity and neck lymph node positivity at presentation. The median value of MeHPLAase activity tended to be higher in tumours with low histopathological grade than in those with high histopathological grade. During the follow-up period (median 50 months, range 2-90 months) locoregional recurrences were observed in 31 out of 63 (49%) cases. At the end of the study, 27 out of 63 (43%) patients had died of cancer. Cox univariate analysis using MeHPLAase activity as a continuous covariate showed that the levels of enzymatic activity were inversely associated with the risk of death and relapse. Assuming the mean value of enzymatic activity as the cut-off value, we found a statistically significant relationship between high MeHPLAase activity and longer relapse-free and overall survival. MeHPLAase activity status retained its prognostic significance also in the lymph node-negative subgroup of patients. On multivariate analysis, both EGFR and MeHPLAase activity proved to be independent factors for predicting a short relapse and the overall survival.

Methyl-p-hydroxyphenyllactate-esterase activity in breast cancer: a potentially new prognostic factor in short-term follow-up

We assayed methyl-p-hydroxyphenyllactate esterase (MeHPLAase) activity in 48 cases of primary breast cancer. MeHPLAase activity did not show significant correlation with estrogen receptor and progesterone receptor levels. No significant relationship was found between enzymatic activity and tumor diameter, lymph node status, mitotic activity, degree of nuclear differentiation, and proportion of the S-phase fraction. During the follow-up period (median, 18.8 months; range, 6-69 months), recurrences were observed in 18 of 48 (37%) cases. The Weibull survival regression model using the enzymatic activity as a continuous covariate showed that levels of enzymatic activity were directly associated with the risk of recurrence (P = 0.02). Assuming the mean value of enzymatic activity as the cutoff value, we found a statistically significant relationship between high MeHPLAase activity and shorter recurrence-free survival. On multivariate analysis, MeHPLAase activity proved to be an independent factor for predicting a short period of recurrence-free survival.

Differential sensitivity of leukemic and normal hematopoietic progenitors to the killing effect of hyperthermia and quercetin used in combination: role of heat-shock protein-70

Autologous bone-marrow transplantation (ABMT) is widely used in the treatment of acute leukemias where a matched sibling donor is not available for allogeneic transplantation. However, a major problem in ABMT is relapse, and ex vivo purging may be very important in preventing it. We show here that quercetin enhances the growth-inhibitory effect of hyperthermia (HT) in AML (19 cases) and ALL (6 cases) leukemic blasts. Furthermore, the inhibitory effect of this combined treatment resulted in leukemic-cell apoptosis. On the contrary, normal hematopoietic progenitors were neither growth-inhibited nor induced to apoptosis by HT-plus-quercetin treatment. To explain this difference in sensitivity of leukemic and normal hematopoietic progenitors, we analyzed the effect of quercetin on heat-induced expression of heat-shock protein-70 (HSP-70), which has been shown to be important in regulating thermosensitivity. We found that quercetin inhibits heat-induced HSP-70 expression both at protein and at mRNA levels in AML and ALL blasts. In normal CD34+ progenitors, the combined treatment with HT and quercetin did not reduce HSP-70 expression and did not induce cell apoptosis. Considering the difference in heat sensitivity of normal CD34+ and leukemic progenitors in the presence of quercetin, the combined use of HT and quercetin could constitute a purging protocol for ABMT.

Interaction with type II estrogen binding sites and antiproliferative activity of tamoxifen and quercetin in human non-small-cell lung cancer

The antiestrogen tamoxifen is thought to antagonize the effects of estrogens by competing with them for estrogen receptor (ER) binding. However, tarnoxifen can also reverse multidrug resistance, synergize with cisplatin cytotoxicity, and inhibit growth in ER-negative lung cancer cells. In addition to ERs, rat and human target tissues contain a second binding macromolecule termed the type II estrogen binding site (type II EBS). It has been shown that tamoxifen and flavonoids, a widely distributed class of natural substances with a variety of biologic actions, bind to type II EBS and inhibit the growth of several tumor cell types. At present, conflicting data about ERs and an absence of data about type II EBSs exist for lung tumors. We have tested non-small-cell lung carcinoma cell lines and primary tumor cells for the presence of ERs and type II EBSs and have evaluated the effects of tamoxifen and quercetin (pentahydroxyflavone) on the growth of these cells. Using a whole-cell assay and nuclear and cytosolic radiobinding experiments with [3H]estradiol as tracer, we have found that SK-LU1, SW900, ChaGo-K-1, H441, H661, and A549 cells, as well as primary tumors, bind estrogen specifically. This binding results mainly from the presence of a large number of type II EBSs, whereas ERs are absent or present at low concentrations. Type II EBSs bound tamoxifen and quercetin with similar affinity. Cell counts and a thymidine incorporation assay showed that both compounds inhibit cell growth in a concentration-dependent manner at concentrations ranging from 10 nM to 1 microM. Neither ipriflavone, an isoflavone, nor rutin, the 3-rhamnosylglucoside of quercetin, bound type II EBSs or inhibited cell growth. These findings suggest that tamoxifen and quercetin could regulate lung cancer cell growth through a binding interaction with type II EBSs. This mechanism could also be active in vivo, in that we have observed that nuclear and cytosolic type II EBSs were present in all primary lung cancers tested (n = 12), and that tamoxifen and quercetin were effective in inhibiting in vitro bromodeoxyuridine (BrdU) incorporation and proliferation-cell nuclear antigen expression by neoplastic cells in these cancers.

Immunohistochemical and in situ hybridization detection of growth-hormone-producing cells in human thymoma

We have studied 25 thymomas by both immunohistochemistry and in situ hybridization for the presence of growth hormone (GH)-producing cells. Our results indicate that 1) GH-immunoreactive cells were present in 13 of 17 thymomas of cortical and predominantly cortical type but not in medullary (spindled) thymomas (n = 3) or low- to high-grade thymic carcinomas (n = 5), 2) GH-positive cells were mainly located at the periphery of the neoplastic lobules, at the periphery of the perivascular spaces and in the areas of medullary differentiation, 3) cells containing GH mRNA appeared at locations similar to those of GH-immunoreactive cells, and 4) GH-immunoreactive material was present only in the epithelial cell component as revealed by immunoelectron microscopy. In conclusion, this paper demonstrates the occurrence of GH-producing cells in noncarcinoid thymic tumors. The relevance of GH in thymoma cell biology requires additional investigations.

Interleukin 1alpha and interleukin 6 promote the in vitro growth of both normal and neoplastic human cervical epithelial cells

Interleukin 1alpha (IL-1alpha), Interleukin 6 (IL-6) and epidermal growth factor (EGF) were tested for their ability to regulate epithelial cervical cell cytokine production and secretion and to induce proliferation of human normal and neoplastic epithelial cervical cells. IL-1alpha, and IL-6 enhanced tumour and normal cell growth by 20-120%. The interleukins efficacy was similar to that of EGF for some cell lines but not for normal esocervical cells. The stimulatory effects of the interleukins were observed in both human papilloma virus (HPV)-infected and HPV-non-infected cervical cells. Normal cells constitutively expressed IL-1alpha, IL-6 and EGF mRNA. All cell lines except C33A expressed IL-1alpha mRNA. CaSki, C-4II and HT-3 expressed mRNA for IL-6. IL-1alpha induced or increased IL-6 mRNA levels in the Me-180 and HT-3 lines and in normal cervical cells. IL-6 induced: (1) the expression of its own mRNA only in Me-180 cells that constitutively lacked IL-6 mRNA; (2) the expression of IL-1alpha mRNA in C-33A and increased IL-1alpha mRNA level in the case of Me180 cells. Increased amounts of IL-6 mRNA were found in normal cells when treated with IL-1alpha. In spite of the pattern of mRNA expression, only HT-3 and normal cervical cells constitutively secreted IL-6, and only normal cells were able to produce IL-1alpha protein. A significant IL-1alpha-dependent increase of IL-6 secretion was found in Me-1 80, HT-3 and normal cells. IL-1alpha- and IL-6-driven cell proliferations were almost completely inhibited by the addition of neutralizing anti-IL-6 antibodies. Taken together, these data suggest that interleukins play a role in cervical carcinogenesis as autocrine and/or paracrine stimuli.

Quercetin and the growth of leukemic progenitors

The bioflavonoid quercetin (3, 3', 4', 5-7-pentahydroxyflavone) inhibits in a dose-dependent manner the in vitro growth of acute leukemias and enhances the anti-proliferative activity of cytosine arabinoside. Quercetin exerts a blocking action of cell transition from the G0/G1 to the S phase of the cell cycle. Acute myeloid leukemias (AML)-M3,-M4 and -M5, and acute lymphoid leukemias (ALL) were more sensitive to quercetin than AML-M1 and -M2 subtypes. The sensitivity of leukemic progenitors to the growth inhibitory effect of quercetin significantly correlated with their clonogenic efficiency. We postulate that quercetin exerts its growth inhibitory action by interaction with type II estrogen binding sites and subsequent induction of Transforming Growth Factor-beta 1 expression and secretion. Finally quercetin is synergistic with hyperthermia in inducing apoptosis of leukemic cells sparing normal stem cell progenitors. Taken together these results stress the potential role of quercetin in the treatment of acute leukemias and its in vitro use in purging procedures for autologous bone marrow transplantation.

Depletion of stromal and intraepithelial antigen-presenting cells in cervical neoplasia in human immunodeficiency virus infection

Human immunodeficiency virus-positive (HIV+) women have an increased risk of lower genital tract dysplasia and neoplasia, and studies of the central lymphoid system suggest that impaired immunosurveillance plays a role in the development of their cervical tumors. Intraepithelial and stromal immunocompetent cell counts were compared in cervical specimens from 50 HIV+ and 50 appropriately matched HIV-women (controls) with low and high grade squamous intraepithelial lesions (SIL), or carcinoma. Each histological class of HIV+ women displayed fewer intraepithelial Langerhans' (S100+) cells (LC) (as already known), and also fewer stromal LC and both intraepithelial and stromal (CD68+) macrophages. LC and macrophages were reduced in all HIV+ patients, whereas reduction of cervical T lymphocytes was found in only immunocompromised subjects (peripheral blood CD4+ T-cell count < 500/microL). A mucosal quantitative deficiency of antigen-presenting cells (APC) thus precedes that of T cells. HIV infection appears to lead to early impairment of mucosal immunoreactivity mainly because of defective antigen presentation. This impairment may be one mechanism underlying the increased frequency of cervical dysplasia/neoplasia, and the enhanced aggressiveness of invasive cancers in HIV+ women.

nm23 in ovarian cancer: correlation with clinical outcome and other clinicopathologic and biochemical prognostic parameters

PURPOSE

The aim of the study was to define the prognostic role of the metastasis suppressor gene, nm23, in 106 primary ovarian cancer patients.

PATIENTS AND METHODS

Northern and Western blotting analysis of nm23-H1 and nm23-H2 expression were performed in a subset of ovarian tumors. Immunohistochemical analysis was performed on formalin-fixed paraffin-embedded specimens from 106 primary ovarian carcinomas by the antihuman nm23 monoclonal antibody.

RESULTS

Northern and Western blotting analysis demonstrated a direct association between nm23-H1 and nm23-H2 levels. Moreover, an overall concordance of 86.7% between Northern blotting and immunohistochemical data was observed. Sixty-six specimens (68%) showed a positive nm23-H1 immunoreaction. The percentage of nm23-H1 positivity was higher in lymph node-negative (70%) than in lymph node-positive cases (44%) (P = .049). Moreover, the percentage of complete/partial responses to chemotherapy was higher in nm23-H1-positive (69%) than in nm23-H1-negative (44%) patients (P = .03). The percentage of epidermal growth factor receptor (EGFR) positive cases was lower in nm23-H1-positive (44%) than in nm23-H1-negative immunostained (72%) samples (P = .012). Lower ras/p21 levels (median, 1.77 absorbance units) were found in nm23-H1-positive than in nm23-H1-negative samples (median, 2.63 absorbance units) (P = .03). The 6-year progression-free survival (PFS) rate of nm23-H1-positive cases was 50% (95% confidence interval [CI], 33 to 67) versus 12% (95% CI, -2 to 26) for nm23-H1-negative patients (P = .0056). In multivariate analysis, only stage, ascites, and nm23-H1 content retained independent prognostic roles.

CONCLUSION

The assessment of nm23 content may provide useful information for prognostic characterization of ovarian cancer patients.

Spontaneous and glucocorticoid-induced apoptosis in human mature T lymphocytes

Glucocorticoid (GC)-induced apoptosis is a well-recognized physiologic regulator of murine T-cell number and function. We have analyzed its mechanisms in human mature T cells, which have been thought to be insensitive until recently. Peripheral blood T cells showed sensitivity to GC-induced apoptosis soon after the proliferative response to a mitogenic stimulation, and were also sensitive to spontaneous (ie, growth factor deprivation-dependent) apoptosis. CD8+ T cells were more sensitive to both forms than CD4+ T cells. Acquisition of sensitivity to GC-induced apoptosis was not associated with any change in number or affinity of GC receptors. Both spontaneous and GC-induced apoptosis were increased by the macromolecular synthesis inhibitors, cycloheximide (CHX) and puromycin. A positive correlation between the degree of protein synthesis inhibition and the extent of apoptosis was observed. Interleukin-2 (IL-2) IL-4, and IL-10 protected (IL-2 > IL-10 > IL-4) T cells from both forms of apoptosis in a dose-dependent manner. Our data suggest that spontaneous and GC-induced apoptosis regulate the human mature T-cell repertoire by acting early after the immune response and differentially affecting T-cell subsets.

Interaction of tamoxifen with cytosolic and nuclear type II estrogen binding sites (type II EBS)

The aim of this study was to investigate the interaction of tamoxifen (TAM) with the so-called Type II estrogen binding sites (Type II EBS) in both the cytosolic and the nuclear fraction of the ER-negative A 2780 human ovarian cancer cell line and in an ER-negative ovarian cancer tissue. Although cytosolic and nuclear Type II EBS in A 2780 cells showed substantially similar binding characteristics in terms of ligand affinity and specificity, TAM, while exhibiting the ability to displace [3H]estradiol from cytosolic Type II EBS failed to interact with nuclear Type II EBS. The ability of TAM to interact only with cytosolic Type II EBS seems also to be a characteristic of ovarian cancer tissue and to be shared by several TAM metabolites. The hypothesis that the interaction of TAM with cytosolic Type II EBS could mobilize the true endogenous ligand of Type II EBS which would become available for binding to nuclear Type II EBS was tested by incubating the nuclear fraction with the cytosolic fraction. In the presence of cytosol, TAM acquires the ability to displace the tracer from nuclear Type II EBS but when the cytosolic fraction was DCC, stripped in order to remove the endogenous ligand, the competing activity of TAM for nuclear Type II EBS was abolished. Our results suggest that TAM does not interact with nuclear Type II EBS, but can favor the nuclear binding of endogenous ligand by displacing it from cytosolic Type II EBS.

Methyl-p-hydroxyphenyllactate-esterase activity and type-II estrogen-binding sites in ovarian cancer: correlation with biological and clinico-pathological parameters

We examined the levels of activity of methyl-p-hydroxyphenyllactate esterase (MeHPLA-ase) and cytosolic Type-II-estrogen-binding sites (Type-II EBS) in 61 and 71 cases, respectively, of primary ovarian cancer. MeHPLA-ase activity and Type-II EBS were seen to by asymmetrically distributed, in that levels were skewed towards the lower values. A statistically significant direct correlation was found between MeHPLA-ase activity and Type-II EBS. MeHPLA-ase activity and Type-II EBS were inversely correlated with ER and PR levels and showed a trend towards inverse correlation with the percentage of cells in S-phase of the cell cycle. MeHPLA-ase activity and Type-II EBS did not correlate with clinico-pathological parameters. The median MeHPLA-ase activity tended to be higher in responders than in unresponsive patients, but statistical significance was not reached. Higher Type-II-EBS levels were found in cases showing complete and partial response to chemotherapy than in cases which did not respond. A statistically significant relationship was found between high MeHPLA-ase activity and longer overall survival.