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J Jouanneau

Publications and source records attributed to J Jouanneau.

At least 19 recordsLinked to original sources
PubMed2002

NBT-II carcinoma behaviour is not dependent on cell-cell communication through gap junctions.

To study the mechanism(s) underlying the proliferation of heterogeneous cell populations within a solid tumour, the NBT-II rat bladder carcinoma system was used. It has been first investigated whether the different cell populations are coupled through gap junctions (GJIC). Cells overexpressing the Cx43 were generated to test for any tumour suppressive activity in vivo. To determine whether GJIC is essential for tumour proliferation and the establishment of a cooperative community effect, NBT-II cells that are incompetent for cell coupling were generated. The data report that (i) carcinoma cells expressing or not FGF-1 are coupled through GJIC in vitro and in coculture and express the gap junction protein Cx43, (ii) overexpression of Cx43 in these cells does not affect their in vitro coupling capacities and in vivo tumourigenic growth properties, (iii) inhibition of GJIC through antisense strategy has no in vivo obvious consequence on the tumour growth properties of the carcinoma, and (iv) the community effect between two carcinoma cell populations does not critically involve cell coupling through gap junctions.

Animals↗
PubMed2000

Fibroblast growth factor-2.

Fibroblast growth factor-2 (FGF-2) is a heparin-binding growth factor which occurs in several isoforms resulting from alternative initiations of translation: an 18 kD cytoplasmic isoform and four larger molecular weight nuclear isoforms (22, 22.5, 24 and 34 kD). FGF-2 has pleiotropic roles in many cell types and tissues; it is a motogenic, angiogenic and survival factor which is involved in cell migration, cell differentiation and in a variety of developmental processes. Although devoid of signal peptide, it could be secreted. It acts mainly through a paracrine/autocrine mechanism involving high affinity transmembrane receptors and heparan sulfate proteoglycan low affinity receptors, but also through still unknown intracrine process(es) on intracellular targets. FGF-2 has many biological functions which are probably isoform-specific. Nevertheless, FGF-2 is not essential for embryonic development as knock-out mice for the growth factor are viable and fertile although they exhibit abnormalities in neuronal differentiation. Use of FGF-2 as therapeutic agent for the treatment of ischemic cardiovascular disease is promising and clinical trials are in progress.

Alternative Splicing↗
PubMed1999

Nuclear 24 kD fibroblast growth factor (FGF)-2 confers metastatic properties on rat bladder carcinoma cells.

The tumorigenic and metastatic properties of rat bladder carcinoma NBT-II cells transfected with a cDNA encoding the 24 kD nuclear isoform of human fibroblast growth factor-2 (FGF-2) were analysed and compared with those cells producing the 18 kD cytoplasmic isoform FGF-2. In transfected clones, 24 kD FGF-2 was found in the nucleus, and no FGF-2 was secreted. RT-PCR analysis showed no upregulation of FGF-2-specific receptor FGFR2c expression in these proliferating transfected cells. A shorter latency period for in vivo tumor formation and abundant spontaneous lung metastases were only seen if nuclear FGF-2-producing cells were injected subcutaneously into nude mice. Intravenous injection of 24 kD FGF-2-producing cells led to extensive experimental lung metastases whereas injection of control NBT-II cells or 18 kD FGF-2-producing cells did not. As FGF-2-producing cells have no specific FGF-2 receptors, our results suggest that the 24 kD FGF-2 has nuclear targets, and activates metastatic property of carcinoma cells via a mechanism other than the conventional FGF receptor-mediated signaling pathway.

Animals↗
PubMed1999

Metastatic rat carcinoma cells express a new retrotransposon.

Genes differentially expressed by a rat bladder carcinoma NBT-II cells and their in-vivo-selected metastatic M-NBT-II variant were analysed. Amplification and cloning of a 277-bp B sequence, exclusively expressed by the M-NBT-II cells, were performed, and this sequence was detected as a 6.7-kb RNA. This fragment shares 46-50% identities with the gag-related protein of mouse and hamster Intracisternal A Particles (IAPs). Screening of a M-NBT-II cDNA library with the B probe selected a 1671-bp sequence corresponding to the 5' end of a novel retrotransposon member of the rat IAP family. This sequence has a strong identity with the Ecker Rat IAP (ERA-IAP) except for the B portion and has an open reading frame potentially encoding a 114-amino-acid gag retrovirus-related protein. Rearrangement of this new retrotransposon could be relevant with the tumor progression in our model system since it is only expressed in the M-NBT-II in-vivo-selected carcinoma metastasis.

Amino Acid Sequence↗
PubMed1999

The community effect in FGF-1 mediated tumor progression of a rat bladder carcinoma does not involve a direct paracrine signaling.

A community effect was found to occur between heterogeneous tumor cell populations leading to an overall increased tumorigenicity without a clonal dominance of the more tumorigenic clone. In the rat bladder carcinoma cell line NBT-II, this effect appears mediated by the Fibroblast Growth Factor-1 (FGF-1) through either a direct or an indirect signaling pathway. Neovascularization induced by FGF-1 was found not to be responsible for the community effect. The present study shows that the community effect does not involve a direct FGF-1 signaling since tumor cells expressing a dominant-negative FGF receptor mutant were still responding to the highly tumorigenic FGF-1 expressing cells. Tumors arising from inoculates of the FGF-1 producing NBT-II cells mixed with non tumorigenic epithelial MDCK cells contain only the tumorigenic cells indicating that MDCK cells may exerce a helper effect for the growth of the tumor not dependant on their own growth. Therefore the helper function of MDCK cells must be distinguished from a community effect where the contribution of low tumorigenic cells not only provides an in vivo growth advantage to few highly tumorigenic cells but become themselves highly tumorigenic indicating that the community effect may require cell-cell specific cooperativity independent from an helper effect.

Animals↗
PubMed1999

The SFL activity secreted by metastatic carcinoma cells is related to laminin 5 and mediates cell scattering in an integrin-independent manner.

We have previously reported that an in vivo-selected metastatic variant of NBT-II rat carcinoma cells, M-NBT-II, produces and secretes a factor with cell-scattering activity, SFL, that is potentially involved in tumor progression. This biological activity was purified and characterized as a laminin 5 (LN5) -related protein. This SFL/LN5 protein consists of the (alpha)3, (beta)3 and (gamma)2 chains of expected sizes. Laminin 5 is a multifunctional secreted glycoprotein thought to be involved in cell adhesion and migration, mainly via its interaction with (alpha)3(beta)1 and (alpha)6(beta)4 integrins. SFL/LN5, and purified human laminin 5, induced the scattering and motility of MDCK cells and the formation of actin stress fibers and focal contacts in A549 cells. These events were dependent on activation of the small GTP-binding protein Rho. (Alpha)v colocalized with vinculin in the focal contacts of activated cells whereas (alpha)3 and (alpha)6 integrins did not. Blocking antibodies directed against (alpha)3 and (alpha)6 integrins or the laminin 5 integrin-binding site did not abolish SFL/LN5 biological activity, which, in contrast, was completely inhibited by heparin. Thus, SFL/LN5 activity in epithelial cell scattering and cytoskeletal reorganization is probably independent of integrin receptors.

Animals↗
PubMed1999

[Impact on tumor angiogenesis and tumor progression of expression of the 18 kd and 24 kd isoforms of FGF-2].

The role of FGF-2 in tumor progression and tumor cell invasiveness was investigated using the rat bladder carcinoma cells NBT-II, which do not constitutively express FGF-2 or its membrane-spanning receptor. The NBT-II cells were transfected using expression vectors encoding either the 18 kD or the 24 kD isoform of FGF-2. The 24 kD isoform contains a nuclear localization signal. The transfected NBT-II cells that expressed 18 kD FGF-2 produced and secreted this factor as the biologically active form and retained an epithelial morphology. When injected to nude mice, the tumorigenic potential of these cells was not increased over that of non-transfected NBT-II cells; however, although the time to tumor development was long, the tumors were highly vascularized, indicating secretion of the angiogenic factor FGF-2. The transfected NBT-II cells that expressed 24 kD FGF-2 varied in their morphological appearance and did not secrete FGF-2; immunofluorescence and Western-blot studies showed that the FGF-2 was mainly intranuclear. When injected to nude mice, these cells produced tumors and migrated not only to the lymph nodes but also to the lungs where they produced metastases. In aggregate, these data indicate that stimulation of angiogenesis is not sufficient to increase tumor growth and that nuclear FGF-2 acts as a tumorigenic and metastasis-promoting factor in the NBT-II carcinoma model.

Animals↗
PubMed1997

FGF-2 and FGF-1 expressed in rat bladder carcinoma cells have similar angiogenic potential but different tumorigenic properties in vivo.

The comparative biological properties of NBT-II cells, a rat bladder carcinoma cell line constitutively expressing FGF-1 and FGF-2 were analysed in nude mice. FGF-1 is not secreted by the transfected cells unless the cDNA contains a signal sequence; conversely, NBT-II cells transfected with FGF-2 coding sequence produce and secrete the factor in a biologically active form. Bovine brain capillary endothelial cells are stimulated to proliferate upon addition of medium conditioned by the FGF-2-producing cells and this activity can be abrogated by the addition of anti-FGF-2 blocking antibodies. In addition, the FGF-2-containing medium, which cannot stimulate NBT-II cells due to absence of appropriate receptors, is able to induce scattering of NBT-II cells expressing the FGFR1. It has been reported previously that FGF-1-producing cells are highly tumorigenic in nude mice and induce carcinoma with a period of latency reduced from 6 to 5 weeks when compared to parental NBT-II cells. In contrast, NBT-II cells producing FGF-2 are no more tumorigenic than parental cells, indicating that FGF-1 and FGF-2 have different oncogenic properties in carcinoma. FGF-1 and FGF-2 are potent antiogenic factors that trigger the host endothelial cells. VEGF, another potent angiogen was found to be expressed in small amounts by NBT-II cells and to be expressed in reduced amount in the FGF-producing cells. In the NBT-II system in vivo FGF-1 and FGF-2 are highly and comparatively angiogenic in the resultant carcinoma and this occurs in the absence of production of significant amounts of VEGF by the carcinoma cells. Taken together, our results indicate that activated angiogenesis is not sufficient for rapid tumor expansion. FGF-1 behaves as a tumorigenic factor in the NBT-II bladder carcinoma cell model, whereas expression and secretion of large amounts of FGF-2 are not sufficient for increasing tumor growth.

Animals↗
PubMed1996

Hepatocyte growth factor expressed by a retrovirus-producing cell line enhances retroviral transduction of primary hepatocytes: implications for in vivo gene transfer.

Hepatocyte Growth Factor (HGF) is the more potent mitogen of mature hepatocytes. We have examined the effect of human HGF expression by a recombinant retroviral cell line (MFG-LacZ) on retroviral transduction of primary mouse and human hepatocytes. The HGF in the supernatant of MFG-LacZ cell line was correctly processed and biologically active. Transduction of mouse and human hepatocytes with the supernatant of transfected cells was increased 5-fold, as determined by beta-galactosidase activity. The production of HGF was stable and did not interfere with the viral titers of the producer cells. This study provides evidence that expression of HGF within a retrovirus-producer cell line increases the transduction rate of primary hepatocytes. Since the number of corrected cells is a limiting step for phenotypic correction of liver deficiencies, our approach should improve hepatic gene therapy efficiency. Furthermore this cell line should be useful for in vivo liver gene therapy.

Animals↗
PubMed1995

FGF-1 but not FGF-4 secreted by carcinoma cells promotes in vitro and in vivo angiogenesis and rapid tumor proliferation.

The progressive growth of solid tumors is dependent on the tumor ability to recruit new blood vessels from the surrounding host tissues. We show here that acidic Fibroblast Growth Factor (FGF-1) produced by a rat bladder carcinoma transfected cell line (NBT-II cells) is a potent inducer of angiogenesis. After injection in nude mice, NBT-II cells transfected with FGF-1 form rapidly growing carcinomas which are highly vascularized, whereas carcinoma cells producing a biologically active form of FGF-4 behave like non-producer cells. The vasculature of the tumors obtained with NBT-II cells producing a secreted form of FGF-1 is dramatically expanded but lacking in some places a complete endothelial lining. Conditioned medium from these cells induce formation of capillary-like structures in vitro, whereas those of FGF-4 and non-secreting FGF-1 producing cells failed to induce such structures. Our results indicate that the expression of FGF-1 may promote tumor growth, at least in part, by inducing angiogenesis, and that the acquired ability of tumor cells to secrete FGF-1 but not FGF-4, may result in aberrant neovascularization of the tumor.

Animals↗
PubMed1995

[Molecular aspects of invasiveness and metastasis].

Tumor progression involves the emergence of cell variants with increased proliferative and invasive potentialities. The acquisition of the invasive and metastatic behavior is associated with modulation of cell-cell and cell-substrate interactions. Tumor cells have to dissociate from the primary tumor and migrate through the basal lamina and the surrounding stroma before reaching the vessels. An aberrant expression of some growth factors and their cognate receptors, may contribute to an increase malignancy of tumor cells. We have postulated than such growth factors could be involved in the early events of metastatic spreading by altering cell interactions within a tumor, including proliferation, scattering and migration of tumor cells. In the rat bladder carcinoma NBT-II cell experimental model, we have shown that FGF-1 is a multifunctional factor during tumor progression; FGF-1 acts as a mitogenic factor, a scatter factor, an angiogenic factor, an inducer of matrix degradating enzymes and a tumorigenic factor. NBT-II cells producing constitutively FGF-1 are more invasive, tumorigenic and metastatic than non-producing cells. However, we have shown that within a tumor, FGF-1 producing cells are not dominant in vivo but rather confer by a community effect an "en bloc" behavior to the whole cell collective. This effect could be established either directly by a paracrine mechanism or indirectly by other induced factors. We provide evidence for a novel concept in tumor biology: tumor progression may result from a community effect mediated by a growth/scatter factor produced by a minority of the carcinoma cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Fibroblast Growth Factor 1↗
PubMed1994

A minority of carcinoma cells producing acidic fibroblast growth factor induces a community effect for tumor progression.

It is generally accepted that primary tumors become heterogeneous as a consequence of tumor-cell genetic instability. Clonal dominance has been shown to occur in some experimental models allowing a subpopulation of cells to overgrow the primary heterogeneous tumor and to metastasize. Alternatively, interactions among coexisting tumor subpopulations may contribute to the emergence of a malignant invasive primary solid tumor. We asked the question whether emergence of carcinoma cells producing a growth/dissociating factor within a tumor cell population may be a determinant for tumor progression and for clonal dominance. To mimic such a situation, we have investigated the impact of tumor subpopulation heterogeneity in an in vivo model in which mixtures of carcinoma cells that differ in their ability to produce acidic fibroblast growth factor are injected into nude mice. Our data indicate that a growth-factor-producing cell subpopulation can confer increased tumorigenicity to an entire cell population and subsequently elicit a shorter delay for appearance of metastasis. A community effect via cell interactions may account for a heterogeneous tumor cell population rather than clonal dominance during progression of certain tumor types.

Animals↗
PubMed1994

Alternative splicing in fibroblast growth factor receptor 2 is associated with induced epithelial-mesenchymal transition in rat bladder carcinoma cells.

We described previously that acidic fibroblast growth factor (aFGF), but not basic fibroblast growth factor (bFGF), can induce the rat carcinoma cell line NBT-II to undergo a rapid and reversible transition from epithelial to mesenchymal phenotype (EMT). We now find that NBT-II EMT is stimulated by keratinocyte growth factor (KGF) in cells grown at low density. Accordingly, a high-affinity receptor showing 98% homology to mouse FGF receptor 2b/KGF receptor was cloned and sequenced from NBT-II cells. Northern analysis indicated that mRNA for FGF receptor 2b/KGF receptor was drastically down-regulated within 1 wk in aFGF-induced mesenchymal NBT-II cells. This decrease coincided with an up-regulation of FGF receptor 2c/Bek, a KGF-insensitive, alternatively spliced form of FGF receptor 2b/KGF receptor. Functional studies confirmed that KGF could not maintain EMT induction on mesenchymal NBT-II cells. FGF receptor 1 and FGF receptor 2c/Bek could also support EMT induction when transfected into NBT-II cells in response to aFGF or bFGF. Such transfected cells could bind bFGF as well as aFGF. Therefore, EMT can be induced through different FGF receptors, but EMT may also regulate FGF receptor expression itself.

Alternative Splicing↗
PubMed1994

A scatter factor-like factor is produced by a metastatic variant of a rat bladder carcinoma cell line.

The rat bladder carcinoma epithelial NBT-II cell line undergoes, in vitro, a morphological transition to a fibroblast-like state in the presence of different growth factors. We have selected, in vivo, a metastatic clone, designated M-NBT-II, which has a mesenchymal phenotype and secretes into the culture medium a factor able to dissociate epithelial clusters of NBT-II or MDCK cells. This factor was designated scatter factor-like (SFL) by analogy to the HGF/SF, which has the same dissociating effect in these two cell lines. Here, we show that SFL factor and HGF/SF are different factors: (i) no HGF/SF transcripts could be detected using either specific rat HGF/SF cDNA probes or PCR; (ii) blocking antibodies against rat HGF/SF do not inhibit the SFL activity; and (iii) crude culture medium or partially purified SFL factor-containing fractions do not induce MDCK tubulogenesis, a biological assay that is specific for HGF/SF activity in vitro. We report the partial purification of the SFL factor, based on ion exchange and reverse-phase chromatography. The results indicate that the M-NBT-II metastatic variant secretes a dissociating factor sharing some common biological properties with the HGF/SF, which suggests that the SFL factor is a member of the HGF/SF family and may be involved in tumor progression.

Animals↗
PubMed1994

Creation of an hepatocyte growth factor/scatter factor autocrine loop in carcinoma cells induces invasive properties associated with increased tumorigenicity.

Exogenous HGF/SF converts subconfluent cultures of NBT-II epithelial carcinoma cells into mobile fibroblast-like cells while being only mitogenic for cells maintained at high density. To investigate the potential role of such factor in tumor progression, we generated HGF/SF-producing NBT-II cells by transfection with an expression plasmid containing human HGF/SF cDNA. HGF/SF-producing cells also exhibit a fibroblastic phenotype. Media conditioned by these cells are potent inducers of in vitro tubulogenesis which can be inhibited with specific anti-HGF/SF antibodies; these antibodies are also able to reverse the scattered phenotype of the HGF/SF-producing cells. In addition spheroids of HGF/SF-producing cells are dispersed into 3D collagen gels suggesting an increase of invasive properties of these cells. When injected in nude mice, these HGF/SF-producing cells induce tumors appearing more rapidly than did those obtained with untransfected cells. These results show that HGF/SF can promote motility and invasive properties of NBT-II bladder carcinoma cells and also confers a tumorigenic advantage when acting as an autocrine factor.

Animals↗
PubMed1994

Implication of scatter/growth factors in tumor progression.

Several steps during cancer progression have been distinguished on the basis of anatomo-pathological observations and experimental data. The first step, which consists of the detachment of the cancer cells from the primary tumor prior to their migration, has received much attention. Several lines of evidence have indicated that inducer molecules of tumor cell dispersion are scatter factors which are similar or identical to some growth factors. Our studies have focused on the dispersing effect of growth factors, such as acidic FGF (aFGF) on a rat bladder carcinoma cell line. These studies demonstrated that specific extracellular matrix components might contribute to the scattering effect of soluble growth factors. Additionally, our results indicated that the dispersing action of aFGF is counterbalanced by its mitogenic effect, since these two functions of aFGF cannot be observed simultaneously for the same cell. Depending on its location in the cell collective, a given cell chooses to enter mitosis or to scatter in response to aFGF. The choice between the two responses is apparently driven by molecules belonging to the transducing pathways of aFGF signaling. Finally, our data indicated that aFGF-induced tumor cell scattering leads to increased in vitro invasiveness and in vivo metastasis. Interestingly, the presence of few aFGF-producing tumor cells in a population of non-producing cells dramatically enhances the growth rate and the metastatic properties of the whole tumor, suggesting that a low proportion of highly metastatic cells in a heterogeneous cell population might modify the behavior of the tumor mass.

Animals↗
PubMed1992

Immunohistochemical detection of acidic fibroblast growth factor in bladder transitional cell carcinoma.

Acidic fibroblast growth factor (aFGF) is a regulatory peptide which, on account of its structural homologies with the products of oncogenes, is involved in cell proliferation, differentiation, and motility. We previously reported the presence of aFGF in the urine of patients with transitional cell carcinoma (TCC). aFGF can also induce the motility of a rat-derived bladder carcinoma cell line (NBTII). This immunohistochemical study used polyclonal rabbit antibodies against acidic and basic FGF and peroxidase detection. Native NBTII nude mice xenografts and aFGF transfected NBTII (NFS14) nude mice xenografts were used as tissue controls for antibody specificity. The samples included 4 normal urothelia and 12 TCC. In addition, cytospins of 4 different tumoral cell lines of human bladder and normal bladder cells were stained. The results showed strong immunostaining in all tumoral urothelium samples using anti-aFGF and a very low amount of staining or none at all in healthy tissues. A primary analysis suggested that the strongest reaction was obtained in high-grade tumors (3 + vs + for lower-grade tumors). Using bFGF antibody, strong immunohistochemical staining was detected on basal membranes and stromal vessels and none in urothelium. These data confirm aFGF expression in the epithelial cell compartment of bladder cancer and the likely involvement of this regulatory peptide in the biology of TCC.

Animals↗