Combined inhibition of PI3K and Src kinases demonstrates synergistic therapeutic efficacy in clear-cell renal carcinoma

Potent inhibitors of PI3K (GDC-0941) and Src (Saracatinib) exhibit as individual agents, excellent oral anticancer activity in preclinical models and have entered phase II clinical trials in various cancers. We found that PI3K and Src kinases are dysregulated in clear cell renal carcinomas (ccRCCs), an aggressive disease without effective targeted therapies. In this study we addressed this challenge by testing GDC-0941 and Saracatinib as either single agents or in combination in ccRCC cell lines, as well as in mouse and PDX models. Our findings demonstrate that combined inhibition of PI3K and Src impedes cell growth and invasion and induces cell death of renal carcinoma cells providing preclinical evidence for a pairwise combination of these anticancer drugs as a rational strategy to improve renal cancer treatment.

Anticancer properties of sodium selenite in human glioblastoma cell cluster spheroids

Glioblastoma (GBM) is the most common type of primary tumor of the central nervous system with a poor prognosis, needing the development of new therapeutic drugs. Few studies focused on sodium selenite (SS) effects in cancer cells cultured as multicellular tumor spheroids (MCTS or 3D) closer to in vivo tumor. We investigated SS anticancer effects in three human GBM cell lines cultured in 3D: LN229, U87 (O(6)-methyguanine-DNA-methyltransferase (MGMT) negative) and T98G (MGMT positive). SS absorption was evaluated and the cytotoxicity of SS and temozolomide (TMZ), the standard drug used against GBM, were compared. SS impacts on proliferation, cell death, and invasiveness were evaluated as well as epigenetic modifications by focusing on histone deacetylase (HDAC) activity and dimethyl-histone-3-lysine-9 methylation (H3K9m2), after 24h to 72h SS exposition. SS was absorbed by spheroids and was more cytotoxic than TMZ (i.e., for LN229, the IC50 was 38 fold-more elevated for TMZ than SS, at 72h). SS induced a cell cycle arrest in the S phase and apoptosis via caspase-3. SS decreased carbonic anhydrase-9 (CA9) expression, invasion on a Matrigel matrix and modulated E- and N-Cadherin transcript expressions. SS decreased HDAC activity and modulated H3K9m2 levels. 3D model provides a relevant strategy to screen new drugs and SS is a promising drug against GBM that should now be tested in GBM animal models.

Assessment of annoyance due to urban road traffic noise combined with tramway noise

Due to the expansion of urban areas, an increasing number of residents are exposed to combined community noise sources. Studies show that the exposure to transportation noise significantly affects health and well-being. Noise annoyance is one of these adverse health effects. Up to now, annoyance due to transportation noise is mostly assessed considering single noise exposure situations neglecting the effects of potential interactions between noise sources. In this study, perceptual phenomena involved in noise annoyance due to combined urban road traffic and tramway noises are assessed in laboratory conditions with imaginary and simulated contexts. The urban road traffic was composed of light vehicles, heavy vehicles, buses, and powered-two-wheelers in different driving conditions. The tramway traffic corresponded to tramways in in-curve operating configurations. It could be shown that the road traffic and tramway traffic partial annoyance responses were influenced by each other. Throughout the experiments the strongest component effect prevailed but secondary phenomena could also be observed. Considering the perceptual phenomena highlighted in the analysis, it is shown that total noise annoyance due to the combined noises can be most adequately predicted by the strongest component model. This result was obtained by calculating partial annoyance responses due to urban road and tramway traffic.

Sodium Selenite Decreased HDAC Activity, Cell Proliferation and Induced Apoptosis in Three Human Glioblastoma Cells

AIMS

Selenium (Se) is an essential trace element for human health which also has antitumor properties. Little is known about its effects on brain tumor cells (BTC). The aim of this study was to investigate the anticancer effects of sodium selenite (SS) including histone deacetylase (HDAC) activity in three human glioblastoma (GBM) cell lines (LN229, T98G and U87).

MATERIALS & METHODS

LN229, T98G and U87 GBM cell lines were treated with variable doses of SS for time varying from 24 to 72h. HDAC activity, cell proliferation, toxicity, cell death process, caspase-3 and MMP2 activities and Se absorption were evaluated.

RESULTS

SS modulated all the parameters tested in a dose- and time-dependent manner. We found that SS decreased HDAC activity, blocked cell proliferation and cell cycle at the G2 phase, triggered an apoptotic cell death process caspase-3-dependent and reduced MMP2 activities. All these effects were performed whereas SS was weakly absorbed (<2%).

CONCLUSIONS

SS decreasing HDAC activity exhibited interesting antitumor properties in GBM cells which may be taken into account in the novel strategies for achieving tumor growth inhibition and cytotoxicity. Epigenetic modifications induced by SS should be evaluated in further studies.

An angiosperm-wide analysis of the gynodioecy-dioecy pathway

BACKGROUND AND AIMS

About 6 % of an estimated total of 240 000 species of angiosperms are dioecious. The main precursors of this sexual system are thought to be monoecy and gynodioecy. A previous angiosperm-wide study revealed that many dioecious species have evolved through the monoecy pathway; some case studies and a large body of theoretical research also provide evidence in support of the gynodioecy pathway. If plants have evolved through the gynodioecy pathway, gynodioecious and dioecious species should co-occur in the same genera. However, to date, no large-scale analysis has been conducted to determine the prevalence of the gynodioecy pathway in angiosperms. In this study, this gap in knowledge was addressed by performing an angiosperm-wide survey in order to test for co-occurrence as evidence of the gynodioecy pathway.

METHODS

Data from different sources were compiled to obtain (to our knowledge) the largest dataset on gynodioecy available, with 275 genera that include at least one gynodioecious species. This dataset was combined with a dioecy dataset from the literature, and a study was made of how often dioecious and gynodioecious species could be found in the same genera using a contingency table framework.

KEY RESULTS

It was found that, overall, angiosperm genera with both gynodioecious and dioecious species occur more frequently than expected, in agreement with the gynodioecy pathway. Importantly, this trend holds when studying different classes separately (or sub-classes, orders and families), suggesting that the gynodioecy pathway is not restricted to a few taxa but may instead be widespread in angiosperms.

CONCLUSIONS

This work complements that previously carried out on the monoecy pathway and suggests that gynodioecy is also a common pathway in angiosperms. The results also identify angiosperm families where some (or all) dioecious species may have evolved from gynodioecious precursors. These families could be the targets of future small-scale studies on transitions to dioecy taking phylogeny explicitly into account.

Cellular and molecular mechanisms activating the cell death processes by chalcones: Critical structural effects

Chalcones are naturally occurring compounds with diverse pharmacological activities. Chalcones derive from the common structure: 1,3-diphenylpropenone. The present study aims to better understand the mechanistic pathways triggering chalcones anticancer effects and providing evidences that minor structural difference could lead to important difference in mechanistic effect. We selected two recently investigated chalcones (A and B) and investigated them on glioblastoma cell lines. It was found that chalcone A induced an apoptotic process (type I PCD), via the activation of caspase-3, -8 and -9. Chalcone A also increased CDK1/cyclin B ratios and decreased the mitochondrial transmembrane potential (ΔΨm). Chalcone B induced an autophagic cell death process (type II PCD), ROS-related but independent of both caspases and protein synthesis. Both chalcones increased Bax/Bcl2 ratios and decreased Ki67 and CD71 antigen expressions. The present investigation reveals that despite the close structure of chalcones A and B, significant differences in mechanism of effect were found.

Long-term selenium supplementation in HaCaT cells: importance of chemical form for antagonist (protective versus toxic) activities

The beneficial effect of selenium (Se) on cancer is known to depend on the chemical form, the dose and the duration of the supplementation. The aim of this work was to explore long term antagonist (antioxidant versus toxic) effects of an inorganic (sodium selenite, Na2SeO3) and an organic (seleno-L-methionine, SeMet) forms in human immortalized keratinocytes HaCaT cells. HaCaT cells were supplemented with Na2SeO3 or SeMet at micromolar concentrations for 144 h, followed or not by UVA radiation. Se absorption, effects of UVA radiation, cell morphology, antioxidant profile, cell cycle processing, DNA fragmentation, cell death triggered and caspase-3 activity were determined. At non-toxic doses (10 μM SeMet and 1 μM Na2SeO3), SeMet was better absorbed than Na2SeO3. The protection of HaCaT from UVA-induced cell death was observed only with SeMet despite both forms increased glutathione peroxidase-1 (GPX1) activities and selenoprotein-1 (SEPW1) transcript expression. After UVA irradiation, malondialdehyde (MDA) and SH groups were not modulated whatever Se chemical form. At toxic doses (100 μM SeMet and 5 μM Na2SeO3), Na2SeO3 and SeMet inhibited cell proliferation associated with S-G2 blockage and DNA fragmentation leading to apoptosis caspase-3 dependant. SeMet only led to hydrogen peroxide production and to a decrease in mitochondrial transmembrane potential. Our study of the effects of selenium on HaCaT cells reaffirm the necessity to take into account the chemical form in experimental and intervention studies.

Cytotoxicity of chalcone derivatives towards glioblastoma

BACKGROUND

Among seventeen compounds derived from chalcones investigated as potential anticancer drugs towards LN229 glioblastoma cell line, only two were effective.

MATERIALS AND METHODS

Anticancer activity was investigated by evaluating the cell growth, cell cycle, mitotic index and the cell death.

RESULTS

Two compounds, namely C2 and C12, inhibited cell proliferation associated with a blockade in the G(2)/M phase of the cell cycle and arrested the growth of tumour spheroid mimicking in vivo tumour. C2 blocked cells in the G(2) phase whereas C12 blocked cells in the M phase of the cell cycle. C12 and C2 killed 40% and 95% of the cells respectively using complex mechanisms. The two compounds increased the fluorescence of rhodamine-123 and N-acetylcysteine inhibited their activity, suggesting a role for reactive oxygen species in cell death mediated by these two compounds.

CONCLUSION

C2 and C12 are markedly cytostatic and cytolytic to glioblastoma cells and act through different pathways.

Inhibition of c-Jun N-terminal kinase by SP600125: a cDNA microarray analysis

BACKGROUND

In a previous investigation, we showed that the janus kinase (JNK) inhibitor SP600125 induced several phenotypic and genomic changes in leukemia cells. However, the molecular mechanisms that sustain these changes remain unknown. The purpose of the present study was to examine gene expression changes in THP-1 leukemia cells treated with SP600125.

MATERIALS AND METHODS

Gene expression levels were investigated using Affymetrix hybridization technology and quantitative reverse transcriptase polymerase chain reaction.

RESULTS

Affymetrix technology showed that the expression of 1,038 genes with a biological process description well known in gene ontology was modulated. Fifteen genes were related to kinases or phosphatases, 20 genes were involved in the cell cycle regulation, and 23 genes were involved in apoptosis. A network of 15 correlated genes was obtained showing a primordial role for the myelocytomatosis viral oncogene homolog (MYC).

CONCLUSION

These findings show that SP600125 exhibits cytostatic and cytolytic activities through MYC gene modulation.

A novel chalcone derivative which acts as a microtubule depolymerising agent and an inhibitor of P-gp and BCRP in in-vitro and in-vivo glioblastoma models

BACKGROUND

Over the past decades, in spite of intensive search, no significant increase in the survival of patients with glioblastoma has been obtained. The role of the blood-brain barrier (BBB) and especially the activity of efflux pumps belonging to the ATP Binding Cassette (ABC) family may, in part, explain this defect.

METHODS

The in-vitro activities of JAI-51 on cell proliferation were assessed by various experimental approaches in four human and a murine glioblastoma cell lines. Using drug exclusion assays and flow-cytometry, potential inhibitory effects of JAI-51 on P-gp and BCRP were evaluated in sensitive or resistant cell lines. JAI-51 activity on in-vitro microtubule polymerization was assessed by tubulin polymerization assay and direct binding measurements by analytical ultracentrifugation. Finally, a model of C57BL/6 mice bearing subcutaneous GL26 glioblastoma xenografts was used to assess the activity of the title compound in vivo. An HPLC method was designed to detect JAI-51 in the brain and other target organs of the treated animals, as well as in the tumours.

RESULTS

In the four human and the murine glioblastoma cell lines tested, 10 muM JAI-51 inhibited proliferation and blocked cells in the M phase of the cell cycle, via its activity as a microtubule depolymerising agent. This ligand binds to tubulin with an association constant of 2 x 105 M-1, overlapping the colchicine binding site. JAI-51 also inhibited the activity of P-gp and BCRP, without being a substrate of these efflux pumps. These in vitro studies were reinforced by our in vivo investigations of C57BL/6 mice bearing GL26 glioblastoma xenografts, in which JAI-51 induced a delay in tumour onset and a tumour growth inhibition, following intraperitoneal administration of 96 mg/kg once a week. In accordance with these results, JAI-51 was detected by HPLC in the tumours of the treated animals. Moreover, JAI-51 was detected in the brain, showing that the molecule is also able to cross the BBB.

CONCLUSION

These in vitro and in vivo data suggest that JAI-51 could be a good candidate for a new treatment of tumours of the CNS. Further investigations are in progress to associate the title compound chemotherapy to radiotherapy in a rat model.

Specific inhibition of basal mitogen-activated protein kinases and phosphatidylinositol 3 kinase activities in leukemia cells: a possible therapeutic role for the kinase inhibitors

OBJECTIVE

The roles of phosphatidylinositol 3 (PI3K) and mitogen-activated protein kinases (MAPK) have been widely studied in terms of the differentiation process induced by several drugs (phorbol ester, vitamin D-3, retinoic acid, etc.), but their exact functions in leukemic cells' phenotype and their potential therapeutic role remain incompletely clarified.

MATERIALS AND METHODS

In order to investigate this query, leukemia cells were cultured in presence of kinase inhibitors (KIs). Proliferation, apoptosis, and differentiation were analyzed at the cellular and molecular levels, using flow cytometry and reverse transcriptase quantitative polymerase chain reaction.

RESULTS

SB203580, a P38 MAPK inhibitor, had no effect on cell proliferation, whereas LY294002, a PI3K inhibitor, and PD098059, a selective inhibitor of mitogen-activated extracellular regulated kinase (MEK) phosphorylation, arrested cells in G(0)/G(1). However, LY294002 and PD098059 acted using different mechanisms: LY294002 decreased the expression of phosphorylated S6RP, whereas PD098059 increased P21/waf1 antigen expression. SP600125, an inhibitor of N-terminal c-jun kinases, arrested cells in G(2) and induced an endoreplicative process. SP600125 increased p21 at both the mRNA and protein levels. G(2) blockage is dependent on the PI3K pathway and the endoreplicative process is dependent on the PI3K and extracellular regulated kinase (ERK) pathways and mRNA synthesis. On the other hand, PD098059 potentiated the apoptotic process induced by either SP600125 or LY294002. Modulation of the expression of CD11, CD15, CD18, and CD54 was cell-dependent.

CONCLUSION

Our results suggest that KIs modulate proliferation of leukemia cells and that the MEK/ERK inhibitor, PD098059, in combination with either SP600125 or LY294002, could have clinical value.

2-Arylidenedihydroindole-3-ones: Design, synthesis, and biological activity on bladder carcinoma cell lines

2-Arylidenedihydroindole-3-ones were assayed for their antiproliferative and apoptotic abilities as potential drug candidates to treat bladder tumor. These compounds were tested on cell lines obtained from bladder tumors of various stages [superficial (pTa and pT1) vs. invasive (pT2)]. The most active compound (3c) inhibited the proliferation, induced apoptosis, and decreased the expression of p-Stat5 and p-Pyk2 in DAG-1 and RT112 lines in which the FGFR3 is either mutated or overexpressed. Knowing that FGFR3 is involved in cell proliferation, differentiation, and migration through cell signaling pathways including p-Stat5 way via p-Pyk2, let us assume that compound 3c may probably act through FGFR3 pathway.

Resistance to phorbol ester-induced differentiation in human myeloid leukemia cells: a hypothetic role for the mRNA stabilization process

UM384 cells, derived from the human myeloid leukemia U937 cell line, fail to differentiate in response to 12-O-tetradecanoylphorbol-13-acetate (TPA). Using cDNA microarray and real-time quantitative PCR (RT-QPCR) approaches, we observed a difference in the response to TPA treatment: all the genes from U937 cells were continuously modulated from 2 to 24h. In UM384 cells, 60% of the genes were transiently modulated at 2h, then returned to control levels at 24h. Moreover, HuR, an AU-rich element-binding protein (ARE-BP), was differentially located in the two cell lines. Therefore, a defect of mRNA stabilization could be responsible for the resistance of UM384 cells to TPA-induced differentiation, suggesting a possible role for the post-transcriptional regulation in the leukemogenesis.

In vitro tumoral progression of human bladder carcinoma: role for TGFbeta

OBJECTIVE

Investigating whether extracellular factors are possible actors in tumoral progression in bladder carcinoma.

METHODS

RT112/G2 bladder tumour cells were grown in presence of TGFbeta and analysed by immunological and cDNA microarray techniques.

RESULTS

TGFbeta inhibited cell proliferation, reduced TNFalpha- and IFNgamma-induced apoptosis by decreasing TNFalpha-RI and IFNgamma-R antigen expression. It also inhibited cleaved caspase 8 and 9 expression, decreased E-cadherin, and increased BclxL and cyclooxygenase-2 expression. The cDNA microarray approach showed that TGFbeta up-regulated the expression of genes with defined roles in tumoral progression sometimes associated with poor outcome in bladder cancer.

CONCLUSION

These results suggest that a part of the bladder tumoral progression process may be related to the action of exogenous TGFbeta confirming the possible role for the microenvironment.

Effects of Tumor Necrosis Factor-α (TNFα) and Interferon-γ (IFNγ) on Gene Expression Profiles in Bladder Carcinoma Cells Using Oligonucleotide Microarray Analysis

BACKGROUND

TNFα and IFNγ, two main cytokines secreted in the urine of bladder cancer patients after Bacillus Calmette Guerin immunotherapy (BCG therapy), exert various responses ranging from growth arrest, apoptosis, phenotypic changes and differentiation.

MATERIALS AND METHODS

To identify their transcriptional and translational targets, the highly sensitive bladder cancer cell line (RT112) was treated for 24 hours with increasing doses of IFNγ or TNFα and analyzed for cellular and molecular changes using a cDNA microarray technique (Transcriptome) containing 800 genes.

RESULTS

High doses (>10 ng/ml) induced an apoptotic cell death, whereas low doses (<5 ng/ml) induced a survival program. TNFα-inducible genes, IFNγ-inducible genes and genes modulated by TNFα and IFNγ together were identified. All were related to the tumor progression program including cell proliferation, apoptosis/survival, angiogenesis and metastatic processes.

CONCLUSION

These results suggest that the transcriptomic approach could be a good methodology to determine the molecular mechanisms involved in bladder tumor progression processes in relation to a low response to BCG treatment. However, mRNA and protein expression did not always correlate, suggesting that translational regulation is a vital process in bladder tumor progression.

Is interferon gamma one key of metastatic potential increase in human bladder carcinoma?

PURPOSE

IFN-gamma is detected in the urine of bladder cancer patients after intravesical bacillus Calmette Guerin instillation. Because it acts in the anticancer process, we studied its cellular and molecular mechanisms of action on human bladder cancer cell lines.

RESULTS

IFN-gamma (>5 ng.ml(-1))(>400 IU.ml(-1)) inhibited the growth of bladder cancer cell lines and modified the expression of the tumor-associated markers tissue-type plasminogen activators, Plasminogen activator inhibitor-2, urokinase plasminogen activator receptor, colony-stimulating factor 1, intercellular adhesion molecule 1, and class II MHC. Interestingly, IFN-gamma-induced apoptosis of the low-grade bladder cancer cell lines (RT4/G1 and RT112/G2) related to a cleavage of caspases 1, 8, and 9. This process was inhibited by the phosphatidylinositol 3'-kinase inhibitor (LY294002) and the protein synthesis inhibitor (cycloheximide). Moreover, low doses of IFN-gamma (<5 ng.ml(-1))(<400 IU.ml(-1)) increased the resistance to the cytotoxic effect of tumor necrosis factor alpha in the RT112 cells but not in the RT4 cells. This acquired resistance was associated with morphological changes and with an increase of the cell migration and scattering.

CONCLUSIONS

We demonstrated that in the low-grade bladder cancer cell lines, the effect of IFN-gamma was dose dependent: high doses (>5 ng.ml(-1)) induced apoptosis of RT4 and RT112 cells, whereas low doses (<5 ng.ml(-1)) induced a resistance to the cytotoxic effect of tumor necrosis factor alpha and increase the metastatic potential of the RT112 cells. Therefore, we propose that a similar phenomenon could participate to the immunotherapy failure observed during tumor progression of bladder cancer.

Plasminogen- and colony-stimulating factor-1-associated markers in bladder carcinoma: diagnostic value of urokinase plasminogen activator receptor and plasminogen activator inhibitor type-2 using immunocytochemical analysis

The expression of plasminogen- and colony-stimulating factor-1-associated markers was first investigated in seven bladder carcinoma cell lines and in 15 primary bladder tumors using RT-PCR (mRNAs), zymography (protein activity), ELISA and immunocytochemistry analysis (ICC) (protein levels). The mRNAs expression, the activity and the levels of the secreted proteins were not informative. Only urokinase plasminogen activator receptor (uPA-R/CD87) and possibly plasminogen activator inhibitor type-2 (PAI2) antigen expression at the cellular levels seem to be useful markers. uPA-R antigen expression correlated with the secretion of hepatocyte growth factor (HGF) ( P=0.016) and the motility of the bladder tumor cells ( P=0.014), two markers associated with a poor prognosis in bladder carcinoma. To validate our technique and confirm these preliminary results, uPA-R and PAI2 antigen expression was determined in the imprints from 129 resected bladder carcinoma fragments. uPA-R correlated with the grade ( P=0.002), tumor invasion ( P=0.003) and the ploidy ( P=0.05) of the bladder carcinomas and with the low overall survival ( P=0.045) of the patients. PAI2 correlated only with the stage ( P=0.02) and low overall survival ( P=0.038). We conclude that in bladder carcinomas, studying the transcripts of PAs, PAIs, CSF-1 and its receptor, as well as measuring their concentration or activity in culture supernatants was of no clinical interest in terms of diagnostic or prognostic value. Only the ICC of uPA-R, which correlated with the major histopathological parameters of tumors and the low overall survival, proved to be a diagnostic and prognostic marker.

Dag-1 carcinoma cell in studying the mechanisms of progression and therapeutic resistance in bladder cancer

OBJECTIVE

We describe a new human bladder carcinoma cell line (DAG-1) established from a resected bladder cancer fragment and maintained in culture for more than 5 years and over 300 passages.

METHODS AND RESULTS

Immunological, biochemical and molecular analysis showed that the DAG-1 cells (62 chromosomes) express the cytokeratines 8, 13, 18 and 20 that confirm their epithelial origin as well as numerous cytokine and cytokine receptor mRNAs. They secrete tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), plasminogen activator inhibitors (PAI-1 and PAI-2), and express u-PA receptors (u-PAR/CD87) at their surface. DAG-1 cells are resistant to TNFalpha- and IFNgamma-induced apoptosis, two cytokines secreted in the urine of Calmette-Guérin bacillus-treated patients and involved in the tumor regression.

CONCLUSION

The DAG-1 cell line is a useful tool, both in vitro and in vivo, to study the progression of bladder tumors and their mechanisms of resistance to immunotherapy in relation with PAI-2 and antioxidant enzymes.

Expression of E-, P-, n-cadherins and catenins in human bladder carcinoma cell lines

PURPOSE

Cadherins are cell surface glycoproteins that mediate Ca2+-dependent, homophilic cell-cell adhesion. The classical cadherins, E-, P- and N-cadherins, are known to self-associate from their extracellular domain, while their cytoplasmic domain interacts with either beta-catenin or plakoglobin (gamma-catenin), which in turn is bound to alpha-catenin that links the complex to the actin cytoskeleton. The aim of the present study was to analyze the expression of E-, P- and N-cadherins and catenins in human bladder carcinoma cells.

MATERIALS AND METHODS

Five human bladder carcinoma cell lines, representing a variety of differentiation states, were grown in cell culture. We performed a cell aggregation assay, specific for biological cadherin activity. The expression of cadherins and catenins was analyzed by immunocytochemistry, Western blotting and RT-PCR. The interactions between cadherins and catenins were assessed by immunoprecipitation.

RESULTS

We observed a reduced E-cadherin expression in the poorly differentiated and invasive-tumor derived cells. Interestingly, immunofluorescence study reveals the persistent localization of catenins at intercellular contacts in two E-cadherin deficient cell lines (T24 and TCCSUP) which yet exhibit an epithelial-like morphology and a calcium-dependent adhesive capacity. This suggests that other cadherin(s) are expressed in these both cell lines. P-cadherin, another epithelial cadherin, is expressed only in E-cadherin positive cells. On the other hand, N-cadherin is present at cell-cell borders in the very anaplastic cell lines, T24 and TCCSUP, and is able to link beta-catenin or plakoglobin.

CONCLUSION

These results indicate that N-cadherin may participate in intercellular adhesion, while facilitating bladder tumorigenesis.

Autocrine regulation of TPA-induced apoptosis in monoblastic cell-line U-937: role for TNF-alpha, MnSOD and IL-6

The present studies were undertaken to analyse the factors regulating TPA-induced apoptosis. Treatment of the monoblastic U-937 cells with the phorbol ester, TPA, was found to induce apoptosis in two distinct phases. In phase I (from 0 to 72 hours following TPA induction), apoptotic cells appeared, despite the expression of high levels of the anti-apoptotic Bcl-2 protein. After 96 h. of TPA treatment (phase II), the percentage of apoptotic cells increased as did the cell differentiation stage. The first phase apoptotic response could be significantly reduced (70%) by treatment with anti-tumor necrosis factor-alpha (TNF-alpha) antibody. TNF-alpha protein required de novo RNA and protein synthesis and was found to be mediated by protein kinase and protein tyrosine kinases. Manganese superoxide dismutase (MnSOD) inhibited, whereas IL-6 increased TPA-induced apoptosis. These findings suggest that both TPA, via TNF-alpha synthesis, exerts its protective function intracellularly by inducing MnSOD production and IL-6 may be an effective adjunct to TNF-alpha in the clinic, increasing the antitumor potency of this cytokine.

CK20 gene expression: technical limits for the detection of circulating tumor cells

The suitability of CK20 mRNA expression as a marker for the detection of minimum residual disease in patients with cancer of epithelial origin was evaluated. A sensitive nested RT-PCR assay with multiple replicates was optimised to detect a minimum number of circulating tumor cells expressing cytokeratin 20 (CK20) mRNA. Using this optimal procedure, we examined CK20 mRNA expression in ten epithelial and seven leukemic cell lines, in eight bladder tumors, in peripheral blood samples from 18 tumor patients and from 29 healthy controls and in 8 bone marrow samples from healthy donors. CK20 mRNA was found in 13 of 18 (72%) blood samples from patients with cancer of epithelial origin and in all the epithelial tumor cells tested. However, CK20 mRNA was also detected in 21 of 29 (72%) bloods, in 8 of 8 bone marrow samples from healthy donors and in 4 of 7 leukemic cell lines. These results highlight a requirement for either determination of threshold levels of CK20 normal expression or the development of quantitative techniques to distinguish between a tumor-specific CK20 gene expression and a low level background transcription of this marker. These results would also advise caution in using CK20 as a tumor specific marker in clinical investigations.

Proliferation of LAMA-84 and LAMA-87 cell lines is modulated by autocrine loops involving M-CSF and TGF-beta

The erythromegakaryocytic cell line (LAMA-84) and the erythroeosinophilic cell line (LAMA-87) were used to study receptor expression and receptor-mediated response to monocyte/macrophage colony-stimulating factor (M-CSF) and transforming growth factor beta (TGF-beta), two modulators of cell proliferation. As demonstrated by Northern blot analysis and reverse transcriptase polymerase chain reaction (RT-PCR), c-fms and M-CSF mRNA were expressed in both cell lines. M-CSF was detected in the supernatant of both cell lines and addition of a neutralizing anti-M-CSF antibody inhibited cell growth. The two LAMA cell lines were found to express TGF-beta1, -beta2, and -beta3 mRNAs and to secrete TGF-beta mostly in latent form. Addition of anti-TGF-beta antibodies to the culture medium increased their proliferation, whereas TGF-beta1 inhibited cell proliferation by downregulating the c-myc mRNA. These results show that the proliferation of both LAMA cell lines is positively and negatively regulated by autocrine mechanisms, implying the presence of M-CSF and TGF-beta, respectively. They suggest that similar autocrine loops could be involved in the growth regulation of leukemic cells in vivo.

Quantitative analysis of three-dimensional distribution of AgNOR proteins during interphase in leukemic cells

Acidic proteins of the nucleolar organizer regions, selectively stained by silver (AgNOR-proteins), were investigated during interphase in leukemia cells with a confocal scanning laser microscope (CSLM). Simultaneous confocal fluorescence (for specific labeling of DNA, using propidium iodide) and transmitted light microscopy combined with digital deconvolution (for the location of the AgNOR proteins in nonconfocal mode) were used. The distribution of the AgNOR proteins measured by 3D microscopy was described by their number, the volume occupation of the nucleus by the AgNOR aggregates, the distance between each AgNOR, the distance of each AgNOR to the nucleolar border, and their anisotropy. The results of the 3D analysis were compared to those obtained by conventional 2D analysis, cytogenetical analysis of metaphase nucleolar organiser regions (NORs), and cell duplication rate. The descriptive power of these 3D parameters were assessed for nine leukemic cell lines. The measurements of the 3D spatial distribution of AgNORs was a better discriminant parameter than the morphological parameters (i.e., number and volume). The 3D expression of AgNORs is also a reliable parameter for assessing proliferative activity of leukemic cells and seems to be in relation with the differentiation stage of these leukemic cells.

Selection and characterization of an erythroeosinophilic subclone (LAMA-87) and an eosinophilic subclone (LAMA-88) from the multipotential cell line LAMA-84

The human leukemic cell line LAMA-84 was established and characterized as an erythromegakaryocytic cell line. In the present study we show that these cells can differentiate in estrone-treated athymic mice and give rise to an erythroeosinophilic cell line (LAMA-87). This new cell line expressed glycoporin A, alpha beta and gamma globin chain mRNA but also eosinophilic peroxidase. Hemin slightly increased the total hemoglobin production of the cells and phorbol diester (TPA), dimethyl sulfoxide (DMSO) and sodium butyrate (SB) increased the expression of megakaryocytic markers (gpIIb/IIIa complex). When inoculated into non-treated athymic mice, LAMA-87 cells can differentiate to give rise to eosinomonocytic cells (LAMA-88). This new cell line expresses eosinophilic peroxidase, Luxol fast blue stain and synthesizes lysozyme. Depending on the inducer used, LAMA-88 can differentiate along a monocytic lineage (TPA, DMSO, SB and vitamin D3). These three LAMA cell lines should be useful in further studies of the molecular regulation of the pluripotent cell commitment and may provide a model for the understanding of human hematopoiesis.

Image analysis as a tool for quantitative enzyme determination at the cellular level: application for monocytic differentiation of the UM-384 cell line

Image analysis has been used to determined enzyme activity at the cellular level in individual smeared cells. The counterstains used to visualize smeared cells were chosen to avoid overlap with the chromogene. The amount of the reaction product was quantified by computerised scanning cytophotometry when the conditions of incubation, time and temperature of the reaction, and substrate concentration varied. Under optimal conditions for time, temperature and substrate concentration, a linear relationship was found between enzyme activity determined on smeared cells and in cell lysate. Using these defined conditions, differentiation of UM-384 cells was studied by measuring enzyme activity. After a monocytic differentiation process, induced by sodium butyrate, non-specific esterase cell activity was compared either with differentiation markers (HLA-DR, plasminogen activator inhibitor type 2 and lysozyme) or with markers of proliferation (DNA content) or functional properties (nitroblue tetrazolium reduction and phagocytosis). The results show that, using image analysis, non-specific esterase seems to be a useful means for the assessment of monocytic differentiation whereas myeloperoxidase is not. More generally, quantification of enzyme activity at the cellular level using image analysis can be applied to the study of the differentiation process and may help in the classification of leukemic cells.

The O2- generating oxidase of B lymphocytes: Epstein-Barr virus-immortalized B lymphocytes as a tool for the identification of defective components of the oxidase in chronic granulomatous disease

The O2- generating NADPH oxidase of human Epstein-Barr virus immortalized B lymphocytes (EBV-B lymphocytes) and the NADPH oxidase of human neutrophils were compared. The capacity of the oxidase of EBV-B lymphocytes to generate O2- is 100-fold less than that of neutrophils. Like the oxidase of neutrophils, the oxidase of EBV-B lymphocytes is decreased or abolished in chronic granulomatous disease (CGD). Activation of neutrophil oxidase in an heterologous cell-free system, using human neutrophil membranes and EBV-B lymphocyte cytosol from healthy and CGD patients, combined with immunoblotting investigations of the cytosolic activating factors p47 and p67 involved in O2- production, suggests that neutrophils and EBV-B lymphocytes possess similar complements of cytosolic factors p47 and p67. Cytochrome b -245, the major membrane redox component of the O2- generating oxidase, is only slightly expressed in the membrane of EBV-B lymphocytes. A sensitive and specific immunocytochemical method for detection of the two subunits of cytochrome b -245 is described; it shows that both subunits are virtually absent in EBV-B lymphocytes from CGD patients deficient in the large subunit.

Absence of both subunits of cytochrome b558 in the UM384 cell line relative to the inability to generate superoxide anions

Phagocytic cells are characterized by their ability to generate superoxide anions upon activation by appropriate stimuli. UM384, a myelomonocytic cell line, was shown to be defective in this oxidase activity as measured by nitroblue tetrazolium or cytochrome c reduction. Cytochrome b558, a unique pigment present in phagocytes and implicated in electron transfer from NADPH to O2, was absent in the differentiated UM384 cells. Both subunits of the cytochrome b558 appeared to be absent or present in strongly reduced amounts compared to the mother cell line U937, as indicated by immunocytochemistry or Western blot analysis using monoclonal antibodies (MABs). On the other hand, cytosolic factors also involved in NADPH oxidase activity were shown to be present, either immunologically or by using the capacity of the cytosol to activate the oxidase in a membrane fraction from bovine neutrophils. At the molecular level, the mRNA that encodes the gp91-phox was shown to be absent in the differentiated UM384 cells, whereas the mRNA that encodes the p22-phox was normally expressed. These results suggest that the defect in superoxide production by the UM384 cells is related to the absence of cytochrome b558, a situation mimicking that observed in phagocytes from patients with X-linked chronic granulomatous disease (X-CGD).

Quantification by image analysis of immunocytochemical reactions: application for determination of lysozyme content in individual smeared cells

The objective of the present study was to develop a cytophotometric technique to quantitate immunocytochemical reactions. Cell antigens were detected after immunophosphatase alkaline staining procedure. The amount of reaction product was quantitated by computerized scanning cytophotometry. The technical conditions (dilution of primary antibody; incubation time of the three antibodies; volume and pH of the enzyme substrate reaction; storage of the slides) required for optimal cytophotometric determination of the reaction product were determined. Under these optimally defined conditions, a linear relationship between cell protein content (lysozyme) and microdensitometric measure of the colored reaction product was found. This method could be used for other cells, antigens, and enzymatic indicators.

Establishment and characterization of a granulocytic subclone (UM 384) from the monoblastic cell line U 937

The human cell line U 937 spontaneously expresses monocytic maturation and can be induced into macrophage-like cells when treated with retinoic acid, sodium butyrate, or 2,3-O-tetra decanoylphorbol-13-acetate. We have selected a subclone, designated UM 384, that expresses granulocytic characteristics and can be induced to mature to granulocytes after exposure to retinoic acid, actinomycin D, and dimethylsulfoxide, and to monocyte-like cells when treated with sodium butyrate and phytohemagglutinin-stimulated leukocyte-conditioned medium. These cells retain the same constitutive markers as the parent line including histocompatibility leukocyte antigens and karyotype but share numerous chromosomal abnormalities, mainly t(X;8) (p21;q12).

Human chronic myeloid leukemic cell line with positive Philadelphia chromosome exhibits megakaryocytic and erythroid characteristics

A cell line (LAMA-84) has been established from the blood of a patient with chronic myeloid leukemia in acute phase. LAMA-84 cells retained the patient's chromosome abnormalities, i.e., triplication of all chromosomes except chromosome 18, the presence of Philadelphia (Ph) chromosome in 4-5 copies, and the presence of chromosome markers. LAMA-84 cells have morphological features of undifferentiated blast cells, but analyses have indicated that they belong to the megakaryocytic lineage; platelet peroxidase (PPO) was found in 8.5% of cells; LAMA-84 cells reacted spontaneously with poly- and monoclonal antibodies against the platelet glycoproteins (GP) IIb, IIIa, and the GPIIb/IIIa complex, whose presence was confirmed by crossed immunoelectrophoresis. LAMA-84 cells lack the membrane characteristics of lymphoid and mature granulocytic cells but do, however, react with certain antibodies to immature myeloid cells. Furthermore, they are positive with an antiglycophorin antibody, and contain alpha- and gamma-globin mRNA, thus demonstrating erythroid marker expression. Thus LAMA-84 is a tripotent, megakaryocytic, erythroid, and granulocytic cell line. The megakaryocytic and erythroid markers were enhanced by the addition of DMSO, butyrate, TPA, and hemin. The LAMA-84 cell line represents an interesting tool for the study of megakaryocytic and erythroid differentiation and the mechanisms of neoplastic growth.

Proliferation and maturation of human leukemic cells in liquid culture: activity of human placenta conditioned medium and retinoic acid

Marrow or peripheral blood cells from 28 patients with acute myeloid leukemia (AML) or chronic myeloid leukemia in blastic crisis (CML-BC) were studied in both liquid and agar cultures. The proliferation and maturation of these cells were followed for 15-20 days in liquid culture with or without the addition of human placenta conditioned medium (HPCM) and/or retinoic acid (RA). In nine patients (group 1), cells underwent both proliferation and maturation, i.e., the percentage of peroxidase-positive cells (PO), phagocytic cells, and mature forms increased. For the remaining 19 patients (group 2), no proliferation was observed. However, 11 of these leukemic cell samples showed maturation (group 2A), while the eight others remained immature (group 2B). In agar culture, cell samples from group 1 showed cluster growth, group 2 no growth. Maturation without proliferation was observed for group-1 liquid cultures not containing HPCM and those containing HPCM and RA. The viability rapidly decreased in liquid cultures with only addition of RA. HPCM and RA showed no effect on group-2 cell cultures.