Establishment of two new human bladder carcinoma cell lines, CAL 29 and CAL 185. Comparative study of cell scattering and epithelial to mesenchyme transition induced by growth factors.

We describe here two new human urothelial carcinoma cell lines, CAL 29 and CAL 185, established from two patients with high-grade tumours and which display very different properties in vitro. We have shown that CAL 29 cells were tumorigenic in mice and expressed characteristic features of both cell scattering and transition from epithelial to mesenchymal phenotype (EMT) after triggering by the EGF receptor ligands, TGFalpha and EGF. At the opposite, the CAL 185 cells were not tumorigenic in mice and neither scattered nor expressed vimentin intermediary filaments in the presence of growth factors. We further demonstrated that CAL 29 cell scattering was reversible after growth factor removal and that both scattering and EMT were markedly impaired after treatment with MEK, Src and PI3-kinase inhibitors suggesting that these kinases might be important components of the cellular responses to EGF and TGF-alpha leading to scattering and EMT. These agents could help to understand the intracellular pathways involved in invasiveness and to find new targets for limiting metastasis. In conclusion, these two new cell lines could be good models to dissect the molecular mechanisms involved in invasion and metastasis development in human bladder cancer.

Prostaglandin B(2) delivers a co-stimulatory signal leading to T cell activation.

Most of the data accumulated to date on the immunoregulatory effects of prostaglandins (PG) on T cell activation stem from the archetypal inhibitory effect of PGE(2). In this study we provide instead, the first evidence that exogenous PGB(2), a catabolic metabolite of PGE(2), synergizes with signals delivered by T cell receptor (TCR) engagement to induce interleukin-2 (IL-2) production and IL-2 receptor (IL-2R) alpha-expression in Jurkat cells. Accordingly, PGB(2) enhances the proliferation of anti-CD3-activated peripheral blood lymphocytes (PBL). In terms of cellular signaling, we present evidence that PGB(2) activates tyrosine kinase activities and efficiently increases c-fos mRNA expression and nuclear factor-kappa B (NF-kappa B) translocation to the nucleus. Owing to these features, PGB(2) appears as a new lipid mediator capable of delivering an ancillary signal leading to T lymphocyte activation.

Screening of human bladder carcinomas for the presence of Ha-ras codon 12 mutation.

Contradictory results were obtained from previous studies aiming at defining the frequency of Ha-ras codon 12 mutations in bladder tumors. Differences in the sensitivities of the methods used could account for this discrepancy. In this study, we reevaluated the frequency of Ha-ras codon 12 mutations in a series of 87 human bladder tumors using a combination of two different methods. The first was derived from the protocol of Ooi et al and consisted in a one-step allele-specific polymerase chain reaction using mismatched primers in two separate PCR. This method is very rapid and highly sensitive, detecting the presence of minor populations (less than 10%) of mutant alleles. The second strategy consisted in screening all tumors using natural restriction fragment length polymorphism (RFLP) analysis. The two methods were in complete concordance and enabled us to show that only one out of 87 primary bladder carcinomas (1%) exhibited the mutation, in accordance with previous studies. These results strongly suggest that, even if minor cell populations overexpress codon 12 Ha-ras mutation, the analysis of this mutation cannot be used to screen potentially invasive transitional cell tumors of the bladder.

Establishment, characterisation and partial cytokine expression profile of a new human osteosarcoma cell line (CAL 72).

Permanent human osteosarcoma cell lines are important tools for the study of bone cancer. As representative of an osteoblastic phenotype, they partly reflect their normal osteoblastic counterparts and, thus, may represent appropriate models to investigate the mechanisms involved in bone remodelling and in haematopoietic differentiation. In the present work, we describe a new human cell line, CAL 72, obtained from an osteosarcoma of the knee of a 10-year-old boy. These cells grow in continuous culture, and karyotypic analysis has revealed clonal abnormalities in number and structure, especially loss of chromosome Y. These cells exhibit morphological, immuno-histochemical and molecular characteristics of the osteoblastic lineage. Using RT-PCR, we have shown that the CAL 72 cell line expresses high levels of mRNA coding for several cytokines, such as G-CSF, GM-CSF, IL-1beta and IL-6. In view of this expression profile, the CAL 72 phenotype appears to be closer to normal primary osteoblasts than other reported osteosarcomas. Moreover, these cells express mRNA for both HGF and its receptor c-MET, suggesting that this autocrine loop might contribute to the invasiveness of the tumour from which CAL 72 originated.

Regulation of phospholipid metabolism by K+ channel blockers and inhibitors of choline transport in the Jurkat T cell line. Relationships with cell proliferation and interleukin-2 production.

In the human T cell line Jurkat, three drugs generally used as effectors of K+ channels, i.e., quinine, 4-aminopyridine and tetraethylammonium, modify phospholipid metabolism. The drugs inhibited the synthesis of both phosphatidylcholine and phosphatidylethanolamine. The mechanism of such inhibition involves a decreased uptake of choline and ethanolamine by the cells, since the three K+ channel blockers were found to be able to competitively inhibit the high-affinity choline/ethanolamine transport system at the membrane level. In contrast, choline transport-inhibitors such as hemicholinium-3, decamethonium and dodecyltrimethylammonium do not inhibit interleukin-2 synthesis and proliferation of the Jurkat T cell line. This indicates that the inhibition of either phosphatidylcholine and/or phosphatidylethanolamine synthesis is not directly implicated in these processes. The inhibition of interleukin-2 synthesis appeared to be mediated through the inhibition of diacylglycerol production induced by T cell activators. A major role for phosphatidylserine in the regulation of T cell activation emerged, since we demonstrated that a panel of K+ channel blockers enhanced the synthesis of this phospholipid mimicking the previously described effect of exogenously added phosphatidylserine in Jurkat cells, i.e., a blockade of interleukin-2 synthesis probably due to a defect in diacylglycerol production.

[Images of population potential in Europe]. / Images de potentiels de population en Europe.

"The paper proposes an evaluation of relative locations in Europe circa 1990, based on a new, probabilistic, formulation of the concept of population potential. The location of centres and peripheries, as highlighted by potential, varies according to the geographical importance of exchanges and the permeability of national boundaries. An extremely stable overall pattern emerges from two analyses, the one retrospective--using data for 1960--and the other prospective--based on the distribution of young people today--: regions with a high potential are located in concentric circles around the axis formed by the Rhine, not in the peripheral regions of Europe where population growth is higher." (SUMMARY IN ENG)

Changes in phospholipid metabolism induced by quinine, 4-aminopyridine and tetraethylammonium in the monocytic cell line THP1.

Quinine, 4-aminopyridine and tetraethylammonium, three compounds generally used as effectors of K+ channels, strongly modify phospholipid metabolism. In the human monocytic cell line THP1, the three drugs enhanced the incorporation of [3H]serine into phosphatidylserine and that of [3H]inositol into phosphatidylinositol in the absence of significant changes in the uptake of the 3H labels. On the contrary, the biosynthesis of both phosphatidylcholine and phosphatidylethanolamine was strongly inhibited. This inhibition appeared to be mainly due to the inhibition of both [3H]choline and [3H]ethanolamine uptake by the cells, by impairment of choline transport in a competitive mode.