Establishment and characterisation of a new breast cancer xenograft obtained from a woman carrying a germline BRCA2 mutation.

BACKGROUND: The BRCA2 gene is responsible for a high number of hereditary breast and ovarian cancers, and studies of the BRCA2 biological functions are limited by the lack of models that resemble the patient's tumour features. The aim of this study was to establish and characterise a new human breast carcinoma xenograft obtained from a woman carrying a germline BRCA2 mutation. METHODS: A transplantable xenograft was obtained by grafting a breast cancer sample into nude mice. The biological and genetic profiles of the xenograft were compared with that of the patient's tumour using histology, immunohistochemistry (IHC), BRCA2 sequencing, comparative genomic hybridisation (CGH), and qRT-PCR. Tumour response to standard chemotherapies was evaluated. RESULTS: Histological profile identified the tumour as a basal-like triple-negative breast cancer. Targeted BRCA2 DNA sequencing of the xenograft showed the presence of the mutation previously identified in the carrier. Comparative genomic hybridisation array profiles of the primary tumour and the xenograft revealed a high number of similar genetic alterations. The therapeutic assessment of the xenograft showed sensitivity to anthracyclin-based chemotherapy and resistance to docetaxel. The xenograft was also highly sensitive to radiotherapy and cisplatin-based treatments. CONCLUSIONS: This study describes a new human breast cancer xenograft obtained from a BRCA2-mutated patient. This xenograft provides a new model for the pre-clinical drug development and for the exploration of the drug response biological basis.

Bilateral projection of nigro-collicular neurons: An electrophysiological analysis in the rat.

In response to stimulation of the deep layers of the superior colliculus (SC) in the rat, nigral neurons were antidromically activated (latency 0.5-1.5 msec). Effective stimulations were located in ipsi- or contralateral SC deep layers lying above the central gray (CG) or more laterally; nigro-collicular neurons are exclusively located in the pars reticulata of the substantia nigra (SN) and some of them project both to ipsi- and contralateral SC. The functional significance of this nigral projection is discussed.

Capacitation of fresh bovine spermatozoa on bovine epithelial oviduct cell monolayers.

Capacitation of fresh bovine spermatozoa on bovine epithelial oviduct cells was assessed1) by the ability of spermatozoa to fertilize bovine oocytes in vitro and2) by exposure to lysophosphatidylcholine (LC) to induce acrosome reaction in the capacitated spermatozoa. When spermatozoa were incubated on bovine epithelial oviduct cells in B2 medium supplemented with 10% estrous cow serum (ECS) and then exposed to 100 microg/ml LC for 15 minutes, the percentage of acrosome reaction induced increased in a time-dependent course, reaching a plateau after 6 hours. Inversely, when spermatozoa were incubated in B2+10% ECS alone, the percentage of acrosome reaction induced by LC didn't fluctuate. The in vitro fertilization rate obtained after incubation of spermatozoa during 6 hours on bovine epithelial oviduct cells in B2+10% ECS medium was on average 75% for both the preovulated and ovulated oocytes. The developmental stages observed 18 hours after male and female gamete co-culture were similar to those obtained after in vivo fertilization. This study suggests that incubation of fresh bovine spermatozoa on bovine oviduct epithelial cell monolayers during 6 hours is an efficient method, and one that is close to in vivo capacitation.

In vitro fertilization of sheep oocytes matured in vivo.

Incubating washed ram spermatozoa in a modified Brackett's defined medium buffered with Hepes (DM-H) containing 20% of heat-inactivated sheep serum appears to be a reliable method of capacitating sperm for in vitro fertilization. Raising the Ca(++) concentration in the fertilization medium (DM-H-SS) to 10 mM stabilized the fertilization rate of various rams (2). This study was designed to determine if the developmental competence of the oocytes fertilized under such conditions was normal. Thirty-seven ewes, treated with progestagen sponges, were superovulated with porcine follicle stimulating hormone (pFSH: 16 mg). An intramuscular injection of gonadotropin releasing hormone (GnRH: 100 mug); given 24 to 26 h after sponge removal, induced the synchronization of ovulations 24 h later. Ovulated oocytes (n = 229) recovered with flushing of the oviducts were inseminated in vitro and 17 h later either fixed in acetic/alcohol (n = 115) to evaluate fertilization or transferred (n = 114) into 38 synchronized recipients (three oocytes/recipient) to evaluate their developmental competence. Of the fixed oocytes, 82.6% were fertilized and 61.7% were monospermic. Nineteen of the recipient ewes (50%) were pregnant at Day 18, and 16 ewes produced a total of 26 live young (mean: 1.63/ewe). The results showed a high efficiency of in vitro fertilization of ovulated oocytes in sheep following a pFSH-GnRH treatment and the in vivo developmental competence of oocytes fertilized in the presence of elevated Ca(++) concentration.

Potentiation of antitumour activity of docetaxel by combination with trastuzumab in a human prostate cancer xenograft model and underlying mechanisms.

Antitumour activity of docetaxel (Taxotere) in hormone-dependent (HD) and hormone-independent (HID) prostate cancer PAC120 xenograft model was previously reported, and its level was associated with HER2 protein expression. In the present study, we evaluate the antitumour effects of docetaxel combined with trastuzumab (Herceptin), an anti-HER2 antibody. Although trastuzumab alone had no effect on tumour growth, it potentiated the antitumour activity of docetaxel in HD tumours and more strongly in HID variants. Using the HID28 variant, we show that docetaxel treatment of tumour-bearing mice induces an increased HER2 mRNA expression of the tyrosine kinase receptor of 25-fold 24 h after docetaxel treatment, while HER2 protein and p-AKT decreased. This was followed by an increase of HER2 protein 3 days (two-fold) after docetaxel treatment and by a strong HER2 release in the serum of treated mice; expression of phospho-ERK, p27, BCL2 and HSP70 concomitantly increased. Similar molecular alterations were induced by docetaxel plus trastuzumab combination, except for that there was a transient and complete disappearance of AR and HSP90 proteins 24 h after treatment. We show that in addition to its known effects on tubulin and mitotic spindles, docetaxel induces complex signalisation pathway mechanisms in surviving cells, including HER2, which can be pharmacologically targeted. This study suggests that the docetaxel/trastuzumab combination may prove an effective therapeutic approach for HER2-expressing hormone-refractory prostate cancer.

Connections from the basal ganglia to the thalamus.

Many data suggest that the basal gnaglia exerts an indirect influence onto the motor cortex through the thalamus which receives pallidal and nigral efferences. According to the anatomical data, the internal segment of globus pallidus projects to the VL-VA and CM of thalamus and the substantia nigra sends axons ending in the VL and VA with an intranuclear organization which did not overlap the pallidal terminations. The electrophysiological records in the VL-VA nucleus demonstrates that pallidal stimulation induces an inhibitory response, mainly on thalamic neurons, which does not receive cerebellar input. If spreading of excitation is avoided, nigral stimulation also induces an inhibition at the thalamic level. This inhibitory effect can be recorded on relay cells with cerebellar input and cortical output as well as on nonrelay cells. The electrophysiological results in the case of the striatopallidal and striatonigral projections are also briefly reported.