Study on polychlorobiphenyl serum levels in French consumers of freshwater fish.

INTRODUCTION: Polychlorobiphenyls (PCBs) are persistent pollutants that are widespread in the environment and in foodstuffs, particularly in freshwater fish, which frequently exceed the maximum levels set by European regulations. OBJECTIVES: First, we describe the consumption of freshwater fish and serum PCB levels in French anglers, a population expected to have the highest level of dietary PCB exposure. Second, we investigated whether there is a statistical relationship between serum PCB levels and the angler consumption of freshwater fish with high PCB bioaccumulation potential (PCB-BP(+) freshwater fish) in order to make recommendations with regard to safe consumption of freshwater fish. METHODS: We conducted a survey of anglers from six sites with contrasting PCB contamination levels. The survey included a food consumption frequency questionnaire and blood samples were taken to assess serum PCB levels. We used a regression model to determine the main factors contributing to serum PCB levels. RESULTS: Consumption of PCB-BP(+) freshwater fish was relatively infrequent. Serum PCB levels of the study population and of women of childbearing age were in the same range as those observed in the French population and in neighbouring European countries, but higher than in the North American population. The two factors with the highest positive association with serum PCB levels were age (R(2)=61%) and the consumption of PCB-BP(+) freshwater fish (R(2)=2%). Using the regression model, we calculated, for several scenarios depending on the age and gender of the population, the maximum annual frequencies for PCB-BP(+) freshwater fish consumption that do not exceed the critical body burden threshold. CONCLUSION: Following the results of this study, the French agency for food, environmental and occupational health and safety (ANSES) issued an opinion and recommended some specific maximum freshwater fish consumption frequencies to protect the French general population.

An apoptosis methylation prognostic signature for early lung cancer in the IFCT-0002 trial.

PURPOSE: To evaluate prognostic and predictive molecular biomarkers in early-stage non-small cell lung carcinoma (NSCLC) receiving neoadjuvant chemotherapy. EXPERIMENTAL DESIGN: The IFCT-0002 trial compared two neoadjuvant regimens in 528 stages I to II NSCLC patients. DNA extraction of snap-frozen surgical samples taken from 208 patients receiving gemcitabine-cisplatin or paclitaxel-carboplatin regimens allowed for the identification of 3p allelic imbalance, Ras association domain family 1A (RASSF1A) and death-associated protein kinase 1 (DAPK1) promoter methylation, and epidermal growth factor receptor, K-ras, and TP53 mutations. Multivariate analysis identified prognostic and predictive effects of molecular alterations. A Bootstrapping approach was used to assess stability of the prognostic models generating optimism corrected indexes. RESULTS: RASSF1A methylation correlated significantly with shorter disease-free survival (DFS; adjusted HR = 1.88, 95% CI: 1.25-2.82, P = 0.0048) and shorter median overall survival (OS; adjusted HR = 2.01, 95% CI: 1.26-3.20, P = 0.020). A computed bootstrap resampling strategy led to a prognostic model, including RASSF1A, DAPK1, and tumor stage, dividing patients into three prognostic groups, with median OS ranging from 34 months for high-risk patients (HR for death = 3.85, 95% CI: 1.79-6.40) to more than 84 months for moderate (HR = 1.85, 95% CI: 0.97-3.52) and low-risk patients (reference group; P = 0.00044). In addition, RASSF1A methylation predicted longer DFS in patients treated with paclitaxel-carboplatin compared with gemcitabine-cisplatin (adjusted HR = 0.47, 95% CI: 0.23-0.97, P(interaction) = 0.042). CONCLUSIONS: Following neoadjuvant chemotherapy, RASSF1A methylation negatively impacted prognosis of early-stage NSCLC. Along with DAPK1 methylation and tumor stage, RASSF1A methylation allowed definition of three subgroups with strikingly different prognosis. Conversely, significantly longer DFS following paclitaxel-based neoadjuvant chemotherapy for patients whose tumors showed RASSF1A methylation suggested its predictive interest in stages I and II NSCLC.

The cell line secretome, a suitable tool for investigating proteins released in vivo by tumors: application to the study of p53-modulated proteins secreted in lung cancer cells.

Malignant processes such as metastasis, invasion, or angiogenesis are tightly dependent on the composition of the extracellular medium, which is itself affected by the release of proteins by the tumor cells. p53, a major tumor suppressor protein very frequently mutated and/or inactivated in cancer cells, is known to modulate the release of proteins by the tumor cells; however, while p53-modulated intracellular proteins have been extensively studied, little is known concerning their extracellular counterparts. Here, we characterized the p53-dependent secretome of a lung tumor model in vitro (H358 human nonsmall cell lung adenocarcinoma cell line with a homozygous deletion of p53) and demonstrate that the modulation of exported proteins can also be detected in vivo in the plasma of tumor-bearing mice. We used a clone of H358, stably transfected with a tetracycline-inducible wild-type p53-expressing vector. With the use of iTRAQ labeling and LC-MALDI-MS/MS analysis, we identified 909 proteins released in vitro by the cells, among which 91 are p53-modulated. Three proteins (GDF-15, FGF-19, and VEGF) were also investigated in H358/TetOn/p53 xenograft mice. The ELISA dosage on total tumor protein extracts confirmed the influence of p53 on the release of these proteins in vivo. Moreover, the GDF-15 concentration was measured in the plasma and its p53-dependent modulation was confirmed. To our knowledge, this is the first report establishing that the in vitro cell line secretome is reliable and reflects the extracellular release of proteins from tumor cells in vivo and could be used to identify putative tumor markers.

Synthesis and biological characterisation of targeted pro-apoptotic peptide.

We report herein the synthesis and in vitro assay of new, multimeric RGD-peptide conjugates for cell-targeted drug delivery. We generated a peptide scaffold comprising two functional domains, one a tumour blood vessel "homing" motif and the other a programmed cell-death-inducing peptide sequence. RGD peptides were selected to direct the molecular conjugate to alpha(V)beta(3) integrin-containing tumour cells. The pro-apoptotic (Lys-Leu-Ala-Lys-Leu-Ala-Lys)(2) peptide was found to be nontoxic outside cells, but toxic when internalized into targeted cells as it disrupted the mitochondrial membrane. The synthesis of these targeted pro-apoptotic conjugates was carried out by assembling three different units (that is, scaffold, RGD units and pro-apoptotic peptide) through chemoselective ligations. We show that one compound displays significant biological effect in alpha(V)beta(3) integrin-containing tumour cells.

Methylation of tumor-suppressor genes in neuroblastoma: The RASSF1A gene is almost always methylated in primary tumors.

BACKGROUND: Currently, the best characterized genetic aberration in neuroblastoma (NB) is MYCN amplification, which has been clearly related to prognosis. In the present study, we investigated whether specific epigenetic alterations are associated with stage of disease. PROCEDURE: Sixty-two NBs (45 primary tumors and 17 NBs at relapse) were studied in terms of the methylation status of 19 genes (p15INK4a, p16INK4a, p14ARF, APC, RB1, RASSF1A, BLU, FHIT, RARbeta, INI1, TIMP3, NF2, MGMT, DAPK, FLIP, ECAD, CASP8, and the receptors DcR1 and DcR2). RESULTS: At diagnosis, we found hypermethylation of RASSF1A in 93% of these tumors, hypermethylation of TIMP3 in 51%, of CASP8 in 38%, of BLU in 34%, of DcR2 in 25%, and of DcR1 in 11%. All 17 tumors tested at relapse showed hypermethylation of RASSF1A (100%), while 10 showed hypermethylation of TIMP3 (59%), six of CASP8 (35%), five of DcR2 (29%), four of BLU (24%), and three of DcR1 (18%). Hypermethylation was related to clinical stage; NBs at stages 1, 2, and 4s were less frequently methylated than stages 3 and 4 disease (P = 0.002). CONCLUSION: These results from our series indicate that hypermethylation of tumor-suppressor genes may be important in the development and evolution of NB. These epigenetic alterations could be used as a marker of the disease and genes regulating methylation should be considered as possible therapeutic targets in NB.

In vivo optical imaging of integrin alphaV-beta3 in mice using multivalent or monovalent cRGD targeting vectors.

BACKGROUND: The cRGD peptide is a promising probe for early non-invasive detection of tumors. This study aimed to demonstrate how RAFT-c(-RGDfK-)4, a molecule allowing a tetrameric presentation of cRGD, improved cRGD-targeting potential using in vivo models of alphaVbeta3-positive or negative tumors. RESULTS: We chose the human embryonic kidney cells HEK293(beta3) (high levels of alphaVbeta3) or HEK293(beta1) (alphaVbeta3-negative but expressing alphaV and beta1) engrafted subcutaneously (s.c.) in mice. Non-invasive in vivo optical imaging demonstrated that as compared to its monomeric cRGD analogue, Cy5-RAFT-c(-RGDfK-)4 injected intravenously had higher uptake, prolonged retention and markedly enhanced contrast in HEK293(beta3) than in the HEK293(beta1) tumors. Blocking studies further demonstrated the targeting specificity and competitive binding ability of the tetramer. CONCLUSION: In conclusion, we demonstrated that Cy5-RAFT-c(-RGDfK-)4 was indeed binding to the alphaVbeta3 receptor and with an improved activity as compared to its monomeric analog, confirming the interest of using multivalent ligands. Intravenous injection of Cy5-RAFT-c(-RGDfK-)4 in this novel pair of HEK293(beta3) and HEK293(beta1) tumors, provided tumor/skin ratio above 15. Such an important contrast plus the opportunity to use the HEK293(beta1) negative control cell line are major assets for the community of researchers working on the design and amelioration of RGD-targeted vectors or on RGD-antagonists.

[Aberrant methylation of tumor suppressor genes in head and neck squamous cell carcinoma: is it clinically relevant?]. / La méthylation des gènes suppresseurs de tumeur dans les cancers des voies aérodigestives supérieures: quelle signification clinique?

During malignant transformation, the malignant cell accumulates epigenetic abnormalities that do not alter the DNA sequence but are transmissible during divisions and modify genes expression. The methylation of CpG islands in the tumor suppressor genes (TS genes) promoters inhibits their transcription ; it is a mecanism of gene inactivation as frequent as allelic deletions. The methylation profile (or panel of methylated genes in a tumor), similarly to allelic deletions, varies with the tumor histology. Within head and neck squamous cell carcinoma (oral cavity, larynx and oropharynx), 19 genes have been analysed, among them 5 are frequently methylated, i.e. : p16, ECAD, DAPK, MGMT et TIMP3. The method of methylation analysis, based on a bisulfite treatment followed by a PCR amplification, is sensitive and specific enough to allow the detection of abnormalities in biological fluid that drain the tumor or in circulating tumoral DNA. In the head and neck squamous cell carcinoma, correlation between the methylation profile in tumor and paired saliva is excellent ; thus methylation analysis in saliva is a very promising approach for early cancer detection in high risk patients or for the post treatment follow up and rapid diagnosis of relapse. The methylation signature might also reflect the tumor prognosis and complete the histology to define the diagnosis. Finally, DNA methylation is reversible with demethylating agents, a new avenue for cancer therapy in association with conventional chemotherapy.

In vivo noninvasive optical imaging of receptor-mediated RGD internalization using self-quenched Cy5-labeled RAFT-c(-RGDfK-)(4).

We reported that regioselectively addressable functionalized template (RAFT)-c(-RGDfK-)(4 )presenting four cyclic (Arg-Gly-Asp) (cRGD) peptides targets integrin alpha(V)beta(3) with an improved specificity compared with monomeric cRGD. In this study, we improved this vector by creating a "stealth" molecule in which a fluorescence quencher (Q) is linked to Cy5 via a disulfide bond (-SS-). RAFT-c(-RGDfK-)(4)-Cy5-SS-Q fluorescence is quenched unless activated by reduction during internalization. RAFT-c(-RGDfK-)(4)-Cy5-SS-Q fluorescence was negligible when compared with the control but totally recovered after cleavage of the disulfide bridge. Confocal microscopy showed that only the intracellular Cy5 signal could be detected using RAFT-c(-RGDfK-)(4)-Cy5-SS-Q, confirming that uncleaved extracellular molecules are not visible. Whole-body imaging of mice bearing subcutaneous tumors injected intravenously with RAFT-c(-RGDfK-)(4)-Cy5-SS-Q showed a very significant enhancement of the fluorescent contrast in tumors compared with the unquenched molecule. Histology of the tumor confirmed the intracellular accumulation of Cy5. These results demonstrate that the presence of a labile disulfide bridge between the targeting vector and a drug mimetic is an efficient way to deliver a dye, or a drug, intracellularly. In addition, this quenched RAFT-c(-RGDfK-)(4)-Cy5-SS-Q probe is a very powerful vector for imaging tumor masses and investigating in vivo RGD-mediated internalization.

Tumor-specific methylation in saliva: a promising biomarker for early detection of head and neck cancer recurrence.

PURPOSE: Our goal was to define tumor and saliva gene methylation profile of head and neck squamous cell carcinoma and to evaluate its prognostic significance and its biomarker potential for early detection of relapse. EXPERIMENTAL DESIGN: We prospectively analyzed 11 genes by methylation-specific PCR on primary tumors, histologically normal adjacent mucosa, and saliva from 90 French patients at diagnosis and during follow-up as well as on 30 saliva specimens from control-matched patients with nonmalignant head and neck pathology. Five additional genes were analyzed on 50 tumors of the series. RESULTS: Methylation of TIMP3, ECAD, p16, MGMT, DAPK, and RASSF1 was the most frequently observed in tumors and paired saliva samples were analyzed at diagnosis, with an excellent agreement between both samples. At least one of these six genes was methylated in >75% of the samples without additional positive samples when other genes were analyzed. Methylation profile was similar in newly diagnosed and second primary cancers. Aberrant methylation was not associated with a worse prognosis. Ninety percent of normal adjacent mucosa and all control saliva samples were negative. Twenty-two patients were followed after treatment; abnormal methylation was detectable in the saliva of five patients few months before clinical and 2-deoxy-2[(18)F]fluoro-d-glucose-positron emission tomography signs of relapse, allowing curable surgery. Saliva samples were negative for the 17 other patients: 16 were in remission and only 1 relapsed. CONCLUSIONS: Gene methylation in saliva is a promising biomarker for the follow-up and early detection of still curable relapses of head and neck squamous cell carcinoma patients.

Oct-4, Rex-1, and Gata-4 expression in human MSC increase the differentiation efficiency but not hTERT expression.

Micro-environment seems to exert an important influence on human mesenchymal stem cell (MSC) differentiation and proliferative capacity in bone marrow as well as in culture ex vivo. Oct-4, Rex-1, and TERT genes are well-known for the maintenance of pluripotentiality differentiation and the proliferative capacity of embryonic stem cells. Some previous data report expression of these embryonic factors in selected clones from bone marrow adult stem cells. Our goal was to study expression of Oct-4, Rex-1, and TERT in primary cultured human MSC according to the serum concentration. In addition, we have studied the expression of Gata-4 since this factor plays a key role in organogenesis. We hypothesized that low serum concentration with appropriate growth factors may induce an undifferentiated status with a re-expression of embryonic factors and extend differentiation capacity. Thus, using a defined culture medium, we report on the increased expression of Oct-4, Rex-1, and Gata-4 in human MSC. We have correlated this expression to an increase in differentiation efficiency towards osteogenic and adipogenic phenotypes. Our data suggest that the culture medium used permits the emergence of adult stem cells with a high differentiation capacity and expression of embryonic factors. These cells may have important implications for cell therapy.

Noninvasive optical imaging of ovarian metastases using Cy5-labeled RAFT-c(-RGDfK-)4.

Our group has developed a new molecular tool based on the use of a regioselectively addressable, functionalized template (RAFT) scaffold, where four cyclic (Arg-Gly-Asp) (cRGD) peptide motifs were grafted. The aim of this study was to determine whether RAFT-c(-RGDfK-)4 combined with optical imaging could allow noninvasive detection of deep ovarian metastases. Human ovarian adenocarcinoma IGROV1 cells expressing low levels of integrin alphaVbeta3 (the main receptor for the cRGD peptide) were used for in vitro and in vivo assays in combination with Cy5-labeled RAFT-c(-RGDfK-)4, cRGD, or RAFT-c(-RbetaADfK-)4. In vivo fluorescence imaging was performed on subcutaneous (SC) tumors and intraperitoneal IGROV1 metastases in nude mice. The accumulation of RGD-Cy5 conjugates in cultured cells or in tumor tissues was examined using confocal laser scanning microscopy. RAFT-c(-RGDfK-)4 exhibited stronger staining in vitro, enhanced tumor-to-background ratio for sc tumors, and allowed early detection of 1- to 5-mm large intraabdominal nodules using noninvasive optical imaging. Histological study revealed that RAFT-c(-RGDfK-)4 accumulated into tumor neovasculature but also into tumor cells. Our data demonstrate that a Cy5-labeled RAFT-c(-RGDfK-)4 is an efficient optical probe for early and noninvasive tumor detection.

Multivalent RGD synthetic peptides as potent alphaVbeta3 integrin ligands.

We study herein the multivalency effect of a cluster of alphaVbeta3-ligands held on a cyclodecapeptide template. An array of RAFT(c[-RGDfK-])n derivatives containing from one to sixteen clustered RGD motifs were synthesized and comparatively assayed in vitro on alphaVbeta3-expressing cells. Efficient inhibition of the alphaVbeta3-specific 23C6 monoclonal antibody fixation was observed with ligands displaying three and four copies of the cyclo[-RGDfK-] peptide.

Methylation of RASSF1A and TRAIL pathway-related genes is frequent in childhood intracranial ependymomas and benign choroid plexus papilloma.

Ependymomas (EP) represent the third most frequent type of central nervous system (CNS) tumor of childhood, after astrocytomas and medulloblastomas. No prognostic biological markers are available, and differentiation from choroid plexus papilloma (CPP) is difficult. The present objective was, for a sample of 27 children with intracranial EP and 7 with CPP, to describe and compare the methylation status of 19 genes (with current HUGO symbol, if any): p15INK4a (CDKN2B), p16INK4a and p14ARF (both CDKN2A), APC, RB1, RASSF1A (RASSF1), BLU (ZMYND10) FHIT, RARB, MGMT, DAPK (DAPK1), ECAD (CDH1), CASP8, TNFRSF10C, TNFRSF10D, FLIP (CFLAR), INI1 (SMARCB1), TIMP3, and NF2. Three adult corteses were used as a control. We detected a similar percentage of methylated tumors in both groups (71% in CPP and 77% in EP). No gene was methylated in that control group. RASSF1A was the most frequently methylated gene in both benign tumors (66%) and EP (56%). The genes associated with apoptosis were methylated in both groups of tumors. The percentages of TRAIL pathway genes (CASP8, TFRSF10C, and TFRSF10D) methylated were 30, 9.5, and 36.4%, respectively, in ependymomas and 50, 50, and 16.7%, respectively, in choroid plexus papillomas. No other gene was methylated in the benign tumors, whereas FHIT was methylated in 22%, RARB in 14.8%, BLU in 13.6%, p16INK4a in 11.1%, TNFRSF10C in 9.5%, and DAPK in 7.4% of ependymomas. Although we did not observe a statistical relationship between methylation and clinical outcome, the methylation pattern does not appear to be randomly distributed in ependymoma and may represent a mechanism of tumor development and evolution.

New multifunctional molecular conjugate vector for targeting, imaging, and therapy of tumors.

We report the in vitro and in vivo characteristics of a new molecular conjugate vector for targeting and imaging of tumors. Its core is a cyclodecapeptide platform named RAFT, onto which two spatially independent functional domains can be covalently and stereospecifically linked: a cell-targeting domain for tumor targeting and a labeling domain able to carry two drugs and/or labeling agents. To prove the interest of this carrier, we used a well-known cRGD cyclopeptide, a ligand for the alphavbeta3 integrin. We demonstrate that this vector presenting four cRGD motifs very efficiently prevents alphavbeta3-mediated cell adhesion to vitronectin. Furthermore, it is actively endocytosed because of the multivalent cRGD presentation, a major advantage for drug delivery. In vivo experiments in nude mice reveal that repeated intratumoral injections of low doses of RAFT(cRGD)4 reduce tumor growth. Furthermore, RAFT(cRGD)4 significantly improves the targeting specificity of subcutaneous tumor masses as well as that of disseminated metastasis after intravenous injection. Thus, RAFT(cRGD)4 is specific, internalized, and perfectly controlled and can carry multiple biological functions on a single, spatially defined backbone, making it a powerful and versatile synthetic vector for drug delivery, molecular imaging, or both.

Poor intercellular transport and absence of enhanced antiproliferative activity after non-viral gene transfer of VP22-P53 or P53-VP22 fusions into p53 null cell lines in vitro or in vivo.

BACKGROUND: The herpes simplex virus type 1 (HSV-1) VP22 protein has the property to mediate intercellular trafficking of heterologous proteins fused to its C- or N-terminus. We have previously shown improved delivery and enhanced therapeutic effect in vitro and in vivo with a P27-VP22 fusion protein. In this report, we were interested in studying the spread and biological activity of VP22 fused to the P53 tumor suppressor. METHODS: Expression of the VP22-P53 and P53-VP22 fusion proteins was shown by Western blot and intercellular spreading was monitored by immunofluorescence on transiently transfected cells. In vitro antiproliferative activity of wild-type (wt) P53 and P53-VP22 was assessed by proliferation assays and transactivating ability was studied by a reporter gene test and a gel-shift assay. Antitumor activity was also tested in vivo by intratumoral injections of naked DNA in a model of subcutaneous tumors implanted in nude mice. RESULTS: Our results show that the C-terminal fusion or the N-terminal P53-VP22 fusion proteins are not able to spread as efficiently as VP22. Moreover, we demonstrate that VP22-P53 does not possess any transactivating ability. P53-VP22 has an antiproliferative activity, but this activity is not superior to the one of P53 alone, in vitro or in vivo. CONCLUSIONS: Our study indicates that a gene transfer strategy using VP22 cannot be considered as a universal system to improve the delivery of any protein.

Cooperation of amphiregulin and insulin-like growth factor-1 inhibits Bax- and Bad-mediated apoptosis via a protein kinase C-dependent pathway in non-small cell lung cancer cells.

Amphiregulin (AR) and insulin-like growth factor-1 (IGF1) are growth factors known to promote non-small cell lung cancer (NSCLC) survival. We have previously published that 1) AR and IGF1, secreted by H358 NSCLC cells, cooperate to protect those cells and H322 NSCLC cells from serum-starved apoptosis; 2) H358 cells resist Bax-induced apoptosis through an inhibition of Bax conformational change. We show here that the antiapoptotic activity of the AR/IGF1 combination is specifically abolished by the PKC inhibitors calphostin C and staurosporine, but not by the MAPK and phosphatidylinositol 3-kinase inhibitors PD98059 and wortmannin, suggesting the involvement of a PKC-dependent and MAPK- and phosphatidylinositol 3-kinase-independent survival pathway. The PKCdelta inhibitor rottlerin restores apoptosis induced by serum deprivation. In addition, phosphorylation of PKCdelta and PKCzeta/lambda, but not of PKCalpha/beta(II), increases in serum-starved H358 cells and in H322 cells treated with an AR/IGF1 combination and is blocked by calphostin C. The combination of AR and IGF1 increases p90(rsk) and Bad phosphorylation as well as inhibiting the conformational change of Bax by a PKC-dependent mechanism. Finally, PKCdelta, PKCzeta, or p90(rsk) small interfering RNAs block the antiapoptotic activity of AR/IGF1 combination but have no effect on partial apoptosis inhibition observed with each factor used alone. Constitutively active PKC expression inhibits serum deprivation-induced apoptosis, whereas a catalytically inactive form of p90(rsk) restores it. Thus, AR and IGF1 cooperate to prevent apoptosis by activating a specific PKC-p90(rsk)-dependent pathway, which leads to Bad and Bax inactivation. This signaling pathway is different to that used by single factor.

Template assembled cyclopeptides as multimeric system for integrin targeting and endocytosis.

The alpha(V)beta(3) integrin receptor plays an important role in human metastasis and tumor-induced angiogenesis. c[-RGDfV-] peptide represents a selective alpha(V)beta(3) integrin ligand that has been extensively used for research, therapy, and diagnosis of neoangiogenesis. We report here the modular synthesis and biological characterization of template assembled cyclopeptides as a multimeric system for targeting and endocytosis of cells expressing alpha(V)beta(3) integrin. c[-RGDfK-] was cleanly assembled in a multivalent mode by chemoselective oxime bond formation to a cyclodecapeptides template labeled by different reporter groups. Binding propensity to the alpha(V)beta(3) receptor and the associated good uptake property displayed by the multivalent molecules demonstrated the interest in the RAFT molecule to design new multimeric system with hitherto unreported properties. These compounds offer an interesting perspective for the reevaluation of integrins as angiogenesis regulators (Hynes, R. O. Nature Med. 2003, 9, 918-921) as well as for the design of more sophisticated systems such as molecular conjugate vectors.

An interaction between CD16 and CR3 enhances iC3b binding to CR3 but is lost during differentiation of monocytes into dendritic cells.

The receptor for the iC3b fragment of complement, CR3, is involved in monocytes/macrophages and neutrophils phagocytosis. CR3 is known to interact with the low affinity receptor for Ig (CD16) and previous studies have suggested that this cooperation modulates CR3 functions. Herein we have studied the effect of CD16 on the ability of human monocytes CR3 to bind to iC3b. We show that iC3b binding to CR3 is inhibited by several reagents that are known to dissociate the CD16/CR3 complex. In addition, treatment of monocytes with soluble CD16 inhibited iC3b binding to CR3. Together, these data indicate that iC3b binding to monocyte CR3 is up-regulated by an interaction between membrane CD16 and CR3. The implication of CD16 in CR3 binding to iC3b was also analyzed after monocyte differentiation into dendritic cells (DC). Differentiation of monocytes into DC abrogates the cooperation between CD16 and CR3, due to a loss of CD16/CR3 interaction. In accordance, this phenomenon is associated with a lack of iC3b binding to DC. As a consequence, deposition of iC3b on apoptotic cells does not modify their phagocytosis by DC. In conclusion, we demonstrate a cooperation between CD16 and CR3 that favors iC3b binding to CR3 but is lost on DC.

[Extracorporeal photochemotherapy for treatment of clonal T cell proliferations]. / La photochimiothérapie extracorporelle dans le traitement de pathologies du système lymphocytaire T.

Extracorporeal photochimiotherapy (ECP) is based on the exposure of peripheral blood mononuclear cells to the photosensitizing agent (psoralen or 8MOP) and UVA radiation. Mononuclear cells are harvested by cytapheresis and reinfused to the patient after irradiation. This cell therapy has been shown to be effective in the treatment of selected diseases mediated by clonal T cells proliferation such as Sezary T cells lymphoma, rejection after solid organ transplantation and graft-versus-host disease but results obtained in autoimmune diseases are less convincing. ECP is well tolerated with very few side effects and can be combined with immunosuppressive drugs. Two methods of ECP are currently used: in the first one, the whole procedure is performed with the same equipment whereas in the second one, the cytapheresis is performed on a conventional cell separator and treated with an independent UVA irradiation: Experimental data and clinical results suggest that PCE might induced an immune response against pathological T cells clones. However, technical differences in the methods of PCE and weak knowledge on its mechanism of action impair the standardization and evaluation of this cell therapy process as well as its clinical development.

VP22-mediated and light-activated delivery of an anti-c-raf1 antisense oligonucleotide improves its activity after intratumoral injection in nude mice.

VP22, a protein of the herpes simplex virus tegument, can form complexes with fluorescein-labeled oligonucleotides. These particles, termed "Vectosomes," are efficiently taken up by cells and remain stable in the cell cytoplasm without any particular activity. Interestingly, these Vectosomes can be disrupted by light, which releases the antisense activity. Here we show that anti-c-raf1 Vectosomes are efficiently activated by light in vivo after injection into subcutaneous A549 (non-small-cell lung cancer) tumors implanted in nude mice. Moreover, two injections per week of anti-c-raf1 Vectosomes followed by illumination result in a stronger inhibition of tumor growth than injections of the antisense alone or of the different control Vectosomes. This effect correlates with a strong inhibition of the c-Raf1 protein expression. As a consequence of c-Raf1 loss, apoptosis was also detected in these tumors. Vectosomes thus represent a new powerful tool to improve the delivery of oligonucleotides in vitro and in vivo.