Céline Bouquet

Microtubule-associated protein 1B controls directionality of growth cone migration and axonal branching in regeneration of adult dorsal root ganglia neurons.

During development, microtubule-associated protein 1B (MAP1B) is one of the earliest MAPs, preferentially localized in axons and growth cones, and plays a role in axonal outgrowth. Although generally downregulated in the adult, we have shown that MAP1B is constitutively highly expressed in adult dorsal root ganglia (DRGs) and associated with central sprouting and peripheral regeneration of these neurons. Mutant mice with a complete MAP1B null allele that survive until adulthood exhibit a reduced myelin sheath diameter and conductance velocity of peripheral axons and lack of the corpus callosum. Here, to determine the function of MAP1B in axonal regeneration, we used cultures of adult DRG explants and/or dissociated neurons derived from this map1b-/- mouse line. Whereas the overall length of regenerating neurites lacking MAP1B was similar to wild-type controls, our analysis revealed two main defects. First, map1b-/- neurites exhibited significantly (twofold) higher terminal and collateral branching. Second, the turning capacity of growth cones (i.e., “choice” of a proper orientation) was impaired. In addition, lack of MAP1B may affect the post-translational modification of tubulin polymers: quantitative analysis showed a reduced amount of acetylated microtubules within growth cones, whereas the distribution of tyrosinated or detyrosinated microtubules was normal. Both growth cone turning and axonal branch formation are known to involve local regulation of the microtubule network. Our results demonstrate that MAP1B plays a role in these processes during plastic changes in the adult. In particular, the data suggest MAP1B implication in the locally coordinated assembly of cytoskeletal components required for branching and straight directional axon growth.

High tumoral levels of Kiss1 and G-protein-coupled receptor 54 expression are correlated with poor prognosis of estrogen receptor-positive breast tumors

KiSS1 is a putative metastasis suppressor gene in melanoma and breast cancer-encoding kisspeptins, which are also described as neuroendocrine regulators of the gonadotropic axis. Negative as well as positive regulation of KiSS1 gene expression by estradiol (E(2)) has been reported in the hypothalamus. Estrogen receptor alpha (ERalpha level is recognized as a marker of breast cancer, raising the question of whether expression of KiSS1 and its G-protein-coupled receptor (GPR54) is down- or upregulated by estrogens in breast cancer cells. KiSS1 was found to be expressed in MDA-MB-231, MCF7, and T47D cell lines, but not in ZR75-1, L56Br, and MDA-MB-435 cells. KiSS1 mRNA levels decreased significantly in ERalpha-negative MDA-MB-231 cells expressing recombinant ERalpha. In contrast, tamoxifen (TAM) treatment of ERalpha-positive MCF7 and T47D cells increased KiSS1 and GPR54 levels. The clinical relevance of this negative regulation of KiSS1 and GPR54 by E(2) was then studied in postmenopausal breast cancers. KiSS1 mRNA increased with the grade of the breast tumors. ERalpha-positive invasive primary tumors expressed sevenfold lower KiSS1 levels than ERalpha-negative tumors. Among ERalpha-positive breast tumors from postmenopausal women treated with TAM, high KiSS1 combined with high GPR54 mRNA tumoral levels was unexpectedly associated with shorter relapse-free survival (RFS) relative to tumors expressing low tumoral mRNA levels of both genes. The contradictory observation of putative metastasis inhibitor role of kisspeptins and RFS to TAM treatment suggests that evaluation of KiSS1 and its receptor tumoral mRNA levels could be new interesting markers of the tumoral resistance to anti-estrogen treatment.

Antitumoral Activity and Osteogenic Potential of Mesenchymal Stem Cells Expressing the Urokinase-Type Plasminogen Antagonist Amino-Terminal Fragment in a Murine Model of Osteolytic Tumor

Prostate cancer metastasis to bone results in mixed osteolytic and osteoblastic lesions associated with high morbidity, and there is mounting evidence that the urokinase‐type plasminogen system is causatively involved in the progression of prostate cancer. Adult mesenchymal stem cells (MSCs) are promising tools for cell‐mediated gene therapy with the advantage of osteogenic potential, a critical issue in the case of osteolytic metastases. In this study, we evaluated the therapeutic use of engineered murine MSCs for in vivo delivery of the urokinase‐type plasminogen antagonist amino‐terminal fragment (hATF) to impair osteolytic prostate cancer cell progression in bone and to repair bone lesions. Bioluminescence imaging revealed that both primary MSCs and the MSC line C3H10T1/2 (C3) expressing hATF (MSC‐hATF) significantly inhibited intratibial PC‐3 Luciferase (Luc) growth following coinjection in SCID mice. Furthermore, microcomputed tomography imaging of vascular network clearly demonstrated a significant decrease in tumor‐associated angiogenesis and a protection from tumor‐induced osteolysis in MSC‐hATF‐treated mice. Importantly, the osteogenic potential of MSC‐hATF cells was unaffected, and an area of new bone formation was evidenced in 60% of animals. Together, these data support the concept of MSC‐based therapy of tumor osteolysis disease, indicating that MSCs may combine properties of vehicle for angiostatic agent with osteogenic potential.

Combined Effects of Docetaxel and Angiostatin Gene Therapy in Prostate Tumor Model

The anti-tumor effects of adenovirus-delivered angiostatin (AdK3) in association with docetaxel (Taxotere) have been evaluated in a human-origin prostate tumor model. In vitro, human endothelial cells were 50- to 100-fold more sensitive to docetaxel than prostate cell lines (PC3, LNCaP, and DU145), and the combination regimen of docetaxel and AdK3 was significantly more cytotoxic for endothelial cells than either treatment alone. PC3 cells, which display the highest sensitivity to docetaxel, were then grafted onto athymic mice for an evaluation of the combined regimen as a therapy. The combination of a single intratumoral injection of AdK3 (2 x 10(9) pfu) and a single intravenous injection of docetaxel (15 mg/kg) was compared with the injection of AdK3 alone on preestablished mice bearing PC3-derived tumors with a mean tumor volume of 60 +/- 11 or 205 +/- 46 mm3. Significant antitumoral effects were observed only in mice receiving the combined treatment. We showed that all PC3 tumors regressed in the AdK3-docetaxel combination group and that 40 to 83% totally regressed. In all cases, this regimen was tightly correlated with a marked decrease in intratumoral vascularization. Our experimental data show that attacking both endothelial and tumoral compartments is an efficient and logical strategy, making this bitherapy approach clinically promising.

Neuronal and glial expression of the adhesion molecule TAG-1 is regulated after peripheral nerve lesion or central neurodegeneration of adult nervous system

Expression of the cell adhesion molecule TAG‐1 is down‐regulated in adult brain, with the exception of certain areas exhibiting structural plasticity. Here, we present evidence that TAG‐1 expression persists also in adult rat spinal cord and dorsal root ganglia (DRG), and can be up‐regulated after injury. On Western blots of adult tissue, TAG‐1 is detected as a 135‐kDa band, with an additional specific 90‐kDa band, not present in developing tissue. TAG‐1 expression is found both in DRG neurons and in Schwann cells, particularly those associated with the peripherally projecting DRG processes. Quantitative in situ hybridization revealed that TAG‐1 expression is significantly higher in small neurons that give rise to unmyelinated fibers, than in large DRG neurons. The regulation of TAG‐1 was then examined in two different lesion paradigms. After a sciatic nerve lesion, TAG‐1 expression is not up‐regulated in DRG neurons, but decreases with time. At the lesion site, reactive Schwann cells up‐regulate TAG‐1, as demonstrated by both immunohistochemistry and in situ hybridization. In a second paradigm, we injected kainic acid into the spinal cord that kills neurons but spares glia and axons. TAG‐1 is up‐regulated in the spinal neuron‐depleted area as well as in the corresponding dorsal and ventral roots, associated with both target‐deprived afferent fibers and with the non‐neuronal cells that invade the lesion site. These results demonstrate a local up‐regulation of TAG‐1 in the adult that is induced in response to injury, suggesting its involvement in axonal re‐modelling, neuron–glia interactions, and glial cell migration.

Safety of rAAV2/2-ND4 Gene Therapy for Leber Hereditary Optic Neuropathy

Leber hereditary optic neuropathy (LHON) is the most commonly recognized mitochondrial disease. It typically occurs in young male adults, causing painless, acute, and profound vision loss. It presents asynchronously with the second eye almost always involved within weeks or months, a phenotypic declaration nearly pathognomonic for LHON. Visual prognosis is poor and therapy wanting. Leber hereditary optic neuropathy is caused by mutations in mitochondrial genes encoding proteins of the respiratory chain complex I. Approximately 70% of subjects with LHON carry the point mutation G11778A in the ND4 gene encoding NADH dehydrogenase protein subunit 4 (ND4), accounting for the most severe phenotype. Retinal ganglion cells are primarily affected by this mitochondrial dysfunction, leading to apoptotic cell death and ensuing optic nerve atrophy. Our therapy is based on a technology that demonstrably rescued an induced defect in respiratory chain complex I in rat retinas and

Recombinant interleukin-2 pre-treatment increases anti-tumor response to paclitaxel by affecting lung P-glycoprotein expression on the Lewis lung carcinoma

The aim of the present study was to examine modifications of anti-tumor activity and toxicity of paclitaxel (PLX) when given p.o. after recombinant interleukin-2 (rIL-2) to Lewis lung carcinoma-bearing mice. PLX was given orally to mice at the dose of 15u2009mg/kg on day 8 and 30u2009mg/kg on day 15, either alone or after 16.5u2009μg of rIL-2 given i.p. twice a day either 1 or 3 days before. The anti-tumor activity was higher and PLX hematological toxicity not increased if orally administered PLX was given after a 3-day rIL-2 pre-treatment rather than if given alone. Lung metastasis was significantly lower and s.c. tumors were smaller in the PLX+rIL-2 group than in the PLX or rIL-2 or non-treated groups. In addition, a decrease in lung P-glycoprotein expression (investigated by Western blot analysis) was observed 1u2009h after the last administration of rIL-2 on day 7.

268. Optogenetic Engineering of Retinal Ganglion Cells with AAV2.7m8-ChrimsonR-tdTomato (GS030-DP) Is Well Tolerated and Induces Functional Responses to Light in Non-Human Primates

Introduction: Expression of a light-sensitive opsin in retinal ganglion cells (RGCs) is an attractive strategy to restore vision. We evaluated the ability of ChrimsonR-tdTomato (ChrR-tdT), derived from the algal light-gated cation channel ChrimsonR (Ed Boyden, MIT), to convert light insensitive RGCs into photoactivatable cells in normal macaques. A photostimulation device (GS030-MD) is developed in parallel to complement the biologics. This GS030 combination treatment is intended to treat blindness caused by retinal degenerative diseases such as retinitis pigmentosa. Methods: Cynomolgus macaques were injected intravitreally with the AAV2.7m8 vector encoding ChrR-tdT under the control of the CAG promoter (GS030-DP; 5×1011 vg/eye). Electrophysiological measurements by microelectrode array (MEA) and patch clamp as well as expression of the ChrR-tdT protein by immunofluorescence were assessed on explanted retinas 2 months after injection. Local tolerance was evaluated by ophthalmic examination and histology at 2 and 6 months post administration. Results: ChR-tdT was essentially expressed in RGCs and its expression restricted to the perifoveal area. MEA recordings showed light responses in all treated retinas, with 3 out of 4 retinas displaying high amplitudes of electrical responses to light stimulation (up to 360 Hz). One retina was less responsive (50 Hz). In patch clamp experiments, conducted by targeting tdT-expressing RGCs, large photocurrents were recorded in 3 out of 4 retinas in response to illumination, and according to the expected action spectrum for ChR-tdT. An exploratory study was conducted in parallel in monkeys, which received a single bilateral intravitreal administration of GS030-DP (5×1011 vg/eye) to assess local tolerance, systemic toxicity and immunogenicity at 2 and 6 months. No clinical signs indicative of systemic toxicity or local intolerance were observed. No adverse effects were seen by ophthalmic or histological examinations, especially no retinal structural modifications, inflammation or necrosis. Anti-AAV2 neutralizing antibodies (NAbs) measured in serum at 2, 3 and 6 months slightly increased at month 2 (≤ 1:100) and then returned to baseline levels at month 6. No NAbs were detected in aqueous humor at necropsy (at 2 or 6 months). In parallel, in preparation of a first-in-man clinical trial, a complete prototype of the photostimulation device (“goggles”) was developed with a full functional optical chain, an electronic subsystem, and firmware and software architecture. These goggles (GS030-MD) capture external scenes through an event-based camera and deliver visual stimuli onto the transduced retina at irradiances shown to activate ChrR-tdT expressing RGCs in monkey retinas. Conclusion: GS030 vector (GS030-DP) transduced efficiently and safely RGCs in vivo after intravitreal administration and induced light responses in normal monkey retinas under pharmacological block of endogenous phototransducion. The GS030 treatment combining the AAV2.7m8-ChrR-tdT vector and the photo stimulation goggles represents a valuable treatment for vision restoration in retinitis pigmentosa.

Interferon-alpha improves docetaxel antitumoral and antimetastatic efficiency in Lewis lung carcinoma bearing mice

AIMSnInterferon-alpha (IFN-α) was shown to reduce P-glycoprotein (P-gp) expression and activity in several tissues. The purpose of this study was to evaluate the impact of IFN-α pretreatment on the antitumoral and antimetastatic, Docetaxel (DTX, P-gp substrate), on Lewis Lung Cancer (3LL) bearing mice and to correlate it to DTX pharmacokinetics.nnnMAIN METHODSnSix groups of C57/Bl6 mice received subcutaneous (s.c.) 2.10(6) 3LL cells, then IFN-α 4MIU/kg for 7days, then received or did not receive i.v. or oral DTX (30mg/kg). Pharmacokinetic studies were done on a part of the mice: DTX concentrations were assessed in plasma and tumors, where AUC were estimated with the Bailer method, and half-lives and MRT were determined with a non-compartmental analysis. Tumor growth was assessed more than 21days: animals were then sacrificed and lung metastases number was counted. Kaplan-Meier analysis was made to analyze survival data during the survey period.nnnKEY FINDINGSnDTX i.v. associated with IFN-α significantly improved mouse survival (19.6±0.6days vs. 17.1±0.8days for control mice, p=0.047) with greater antimetastatic effects (87.5% reduction in the number of metastases compared to control mice). The effect on tumor growth was not modified within the IFN-α/DTX i.v. treated groups when compared to mice receiving DTX i.v. alone. The pharmacokinetic analysis showed an increase of DTX concentrations in tumors at 30min after DTX i.v. administration and an increase in the oral bioavailability of orally given DTX following an IFN-α treatment.nnnSIGNIFICANCEnOur study established that IFN-α increases DTX uptake in tumors, improves its antitumoral efficiency and improves animals survival.

267. Phase I Gene Therapy Preliminary Clinical Results for Treatment of ND4 Leber Hereditary Optic Neuropathy with rAAV2-2-ND4

Introduction Leber Hereditary Optic Neuropathy (LHON) is a rare mitochondrial genetic disorder predominantly affecting young males. Affected patients experience bilateral severe central vision loss. Currently no therapy is approved in the United States to prevent, halt or reverse vision loss due to LHON. Preliminary safety and pharmacodynamic results of a first-in-man trial of GS010, a gene therapy candidate for patients with LHON carrying the ND4 mutation will be presented. Methods GS010 is a recombinant adeno-associated viral vector, serotype 2, carrying the wild-type ND4 gene (rAAV2/2-ND4) and is an experimental gene therapy for the treatment of LHON due to the G11778A ND4 mitochondrial mutation. GS010 has received orphan drug designation in EU & USA. GS010 contains a Mitochondrial Targeting Sequence (MTS) that allows localization of the wild-type protein to the mitochondrion, enabling restoration of mitochondrial function. An open-label Phase I/IIa safety study (NCT02064569) included patients with vision loss due to ND4 LHON and has completed recruitment. Four dose escalation cohorts and an extension cohort were comprised of 3 patients each. Patients received a single intra-vitreal injection of rAAV2/2-ND4 in their worse seeing eye. Primary outcome was the occurrence of adverse events (AE). Secondary outcomes included immune response to AAV2 and evaluation of visual function. Results Systemic safety was excellent as no unexpected adverse events occurred. Ocular tolerability was good with mostly mild inflammation that were responsive to and resolve with standard therapies. Of the first 9 patients with 48 week follow up, preliminary results indicate that symptom duration could impact magnitude of treatment effect. Additionally, baseline vision status at time of treatment also indicate a relation with potential greater magnitude of effect which was noted with relatively shorter disease duration (< 2 years). These data confirm the importance of treating early from onset of vision loss. The RESCUE (NCT02652767) and REVERSE (NCT02652780) Phase III studies of GS010 have been initiated in the United States and some European Union countries. Both studies are randomized, double-masked, sham-controlled trials and will specifically include patients up to 6 months and one year after the onset of vision loss.