Drosophila p53 is required to increase the levels of the dKDM4B demethylase after UV-induced DNA damage to demethylate histone H3 lysine 9

Chromatin undergoes a variety of changes in response to UV-induced DNA damage, including histone acetylation. In human and Drosophila cells, this response is affected by mutations in the tumor suppressor p53. In this work, we report that there is a global decrease in trimethylated Lys-9 in histone H3 (H3K9me3) in salivary gland cells in wild type flies in response to UV irradiation. In contrast, flies with mutations in the Dmp53 gene have reduced basal levels of H3K9me3, which are then increased after UV irradiation. The reduction of H3K9me3 in response to DNA damage occurs preferentially in heterochromatin. Our experiments demonstrate that UV irradiation enhances the levels of Lys-9 demethylase (dKDM4B) transcript and protein in wild type flies, but not in Dmp53 mutant flies. Dmp53 binds to a DNA element in the dKdm4B gene as a response to UV irradiation. Furthermore, heterozygous mutants for the dKdm4B gene are more sensitive to UV irradiation; they are deficient in the removal of cyclobutane-pyrimidine dimers, and the decrease of H3K9me3 levels following DNA damage is not observed in dKdm4B mutant flies. We propose that in response to UV irradiation, Dmp53 enhances the expression of the dKDM4B histone demethylase, which demethylates H3K9me3 preferentially in heterochromatin regions. This mechanism appears to be essential for the proper function of the nucleotide excision repair system.

Intralesional administration of allogeneic bone marrow stromal cells reduces functional deficits after intracerebral hemorrhage

When a severe neurological lesion occurs as a consequence of intracerebral bleeding, no effective treatment for improving the outcome is currently available. In the present study, intracerebral hemorrhage (ICH) was induced by stereotactic injection of 0.5 U of collagenase type IV in the striatum of adult Wistar rats, and three days later, intralesional administration of 2 x 10(6) allogeneic bone marrow stromal cells (BMSC) in saline (n:10), or saline only (n:10), was performed. In the following 30 days, functional outcome was evaluated in each animal by rotarod and the modified neurological severity score (mNSS) test. Progressive and functional improvement was observed in BMSC-transplanted rats compared with controls, together with morphological images suggesting that intracerebral administration of BMSC increases endogenous neurogenesis at the level of subventricular zone (SVZ). These findings suggest that local administration of allogeneic BMSC could be useful to reduce the neurological deficits caused by intracerebral hemorrhage.

Bone marrow stromal cells for spinal cord repair: a challenge for contemporary neurobiology

In the last years, it has been reported that bone marrow stromal cells (BMSC) are able to differentiate towards a neuronal phenotype, in vitro as well as in vivo, and consequently, the possible use of these cells for the treatment of neurological diseases has acquired enormous importance. The objective of this review is to discuss the experimental findings that suggested the utility of BMSC for the treatment of paraplegia, and the possibilities of its clinical application in patients. For this reason, we revise our previous experimental findings about neuronal transdifferentiation of BMSC, and the utility of local BMSC transplantation in an experimental model of chronic paraplegia. Our current experience supports that a neural transdifferentiation of BMSC is possible after these mesenchymal stem cells are transplanted into injured spinal cord tissue. Furthermore, this cell therapy achieves a clear functional improvement of paraplegic animals, together with morphological evidence of spinal cord regeneration. Although at present our efforts should be guided to obtain a better knowledge of the mechanisms of nervous regeneration induced by bone-marrow derived stem cells, it is obvious that cell therapy for nervous system repair is beginning, and BMSC transplantation offers new hope for the treatment of traumatic paraplegia in humans.

p8/TTDA overexpression enhances UV-irradiation resistance and suppresses TFIIH mutations in a Drosophila trichothiodystrophy model

Mutations in certain subunits of the DNA repair/transcription factor complex TFIIH are linked to the human syndromes xeroderma pigmentosum (XP), Cockayne's syndrome (CS), and trichothiodystrophy (TTD). One of these subunits, p8/TTDA, interacts with p52 and XPD and is important in maintaining TFIIH stability. Drosophila mutants in the p52 (Dmp52) subunit exhibit phenotypic defects similar to those observed in TTD patients with defects in p8/TTDA and XPD, including reduced levels of TFIIH. Here, we demonstrate that several Dmp52 phenotypes, including lethality, developmental defects, and sterility, can be suppressed by p8/TTDA overexpression. TFIIH levels were also recovered in rescued flies. In addition, p8/TTDA overexpression suppressed a lethal allele of the Drosophila XPB homolog. Furthermore, transgenic flies overexpressing p8/TTDA were more resistant to UV irradiation than were wild-type flies, apparently because of enhanced efficiency of cyclobutane-pyrimidine-dimers and 6–4 pyrimidine-pyrimidone photoproducts repair. This study is the first using an intact higher-animal model to show that one subunit mutant can trans-complement another subunit in a multi-subunit complex linked to human diseases.

TFIIH participates in RNA polymerase II transcription, nucleotide excision repair, and control of the cell cycle. In humans, certain mutations in the XPB and XPD subunits of TFIIH generate the syndromes trichothiodystrophy (TTD), xeroderma pigmentosum (XP), and Cockayne's syndrome (CS). In contrast, mutations in the p8/TTDA subunit have been linked only to TTD. Cells derived from TTD patients with defects in p8/TTDA have reduced levels of TFIIH. Therefore, it has been proposed that the main function of p8/TTDA is to stabilize and maintain steady-state levels of TFIIH. In Drosophila, mutations in Dmp52 and haywire genes generate phenotypes that share similarities with those associated with mutations in their human counterparts, including reduced TFIIH levels. We report that p8/TTDA overexpression suppressed accumulated developmental defects associated with mutations in the Dmp52 and haywire genes. We also provide evidence suggesting that the rescue of these defects is, in part, because of the recovery of normal TFIIH levels in mutant flies. These results indicate that overexpression of p8/TTDA trans-complemented mutations in other TFIIH subunits and suppressed defects accumulated during fly development. The overexpression of p8/TTDA in wild-type flies increased their UV irradiation resistance, apparently because of more efficient nucleotide excision repair.

From the beginning: the basal transcription machinery and onset of transcription in the early animal embryo

Transcription onset in the early animal embryo is a fundamental process required for proper embryonic development. Depending on the species, transcription onset occurs at what specifically appears to be different developmental stages. However, studies in early embryos from different animal models have shown that components of the basal transcription machinery play fundamental and highly regulated roles at the onset of transcription. The state of the basal transcription machinery in the embryo seems to be equivalent in different organisms at transcription onset. The dynamic balance between putative activators and repressors as well as the chromatin/cytoplasmic ratio seem to be coordinated with basal transcription factors in order to activate zygotic transcription. Here we discuss and compare the regulation of the basal transcription machineries and their activation in early embryos of different model organisms.

DNA repair and transcriptional deficiencies caused by mutations in the Drosophila p52 subunit of TFIIH generate developmental defects and chromosome fragility

The transcription and DNA repair factor TFIIH is composed of 10 subunits. Mutations in the XPB, XPD, and p8 subunits are genetically linked to human diseases, including cancer. However, no reports of mutations in other TFIIH subunits have been reported in higher eukaryotes. Here, we analyze at genetic, molecular, and biochemical levels the Drosophila melanogaster p52 (DMP52) subunit of TFIIH. We found that DMP52 is encoded by the gene marionette in Drosophila and that a defective DMP52 produces UV light-sensitive flies and specific phenotypes during development: organisms are smaller than their wild-type siblings and present tumors and chromosomal instability. The human homologue of DMP52 partially rescues some of these phenotypes. Some of the defects observed in the fly caused by mutations in DMP52 generate trichothiodystrophy and cancer-like phenotypes. Biochemical analysis of DMP52 point mutations introduced in human p52 at positions homologous to those of defects in DMP52 destabilize the interaction between p52 and XPB, another TFIIH subunit, thus compromising the assembly of the complex. This study significantly extends the role of p52 in regulating XPB ATPase activity and, consequently, both its transcriptional and nucleotide excision repair functions.

Oviduct contraction in Drosophila is modulated by a neural network that is both, octopaminergic and glutamatergic

Fertility is a highly complex and regulated phenomenon essential for the survival of any species. To identify Drosophila fertility-specific neural networks, we used a GAL4/UAS enhancer trap genetic screen that selectively inactivates groups of neurons. We identified a GAL4 line (bwktqs) that has a female sterile phenotype only when it expresses the tetanus toxin light chain (TeTxLC). These flies lack oviduct contraction, lay almost no eggs, sperm accumulate in the oviducts, and fewer than normal are seen in the storage organs. In insects, two neuroactive substances are important for oviduct contraction: octopamine (OA), a monoamine that inhibits oviduct contraction, and glutamate (Glu), a neurotransmitter that induces contraction. It is known that octopaminergic neurons of the thoracic abdominal ganglion (TAG) modulate oviduct contraction, however, the glutamatergic neurons that innervate the oviduct have not been identified yet and the interaction between these two neuroactive substances is not well understood. Immunostaining experiments revealed that the bwktqs line trapped an octopaminergic neural network that innervates the genital tract. We show that wt like oviduct contraction in TeTxLC-inactivated flies can only be rescued by simultaneous application of Glu and OA suggesting that the abdominal bwktqs neurons are both octopaminergic and glutamatergic, the use of an agonist and an antagonist for Glu receptors as well as their direct visualization confirmed its participation in this phenomenon. Our work provides the first evidence that adult abdominal type II visceral innervations co-express Glu and OA and allows us to re-evaluate the previous model of neuronal network controlling insect oviduct contraction.

TFIIH trafficking and its nuclear assembly during early Drosophila embryo development

We present the first analysis of the dynamics of the transcription DNA-repair factor TFIIH at the onset of transcription in early Drosophila development. TFIIH is composed of ten polypeptides that are part of two complexes - the core and the CAK. We found that the TFIIH core is initially located in the cytoplasm of syncytial blastoderm embryos, and that after mitotic division ten and until the cellular blastoderm stage, the core moves from the cytoplasm to the nucleus. By contrast, the CAK complex is mostly cytoplasmic during cellularization and during gastrulation. However, both components are positioned at promoters of genes that are activated at transcription onset. Later in development, the CAK complex becomes mostly nuclear and co-localizes in most chromosomal regions with the TFIIH core, but not in all sites, suggesting that the CAK complex could have a TFIIH-independent role in transcription of some loci. We also demonstrate that even though the CAK and the core coexist in the early embryo cytoplasm, they do not interact until they are in the nucleus and suggest that the complete assembly of the ten subunits of TFIIH occurs in the nucleus at the mid-blastula transition. In addition, we present evidence that suggests that DNA helicase subunits XPB and XPD are assembled in the core when they are transported into the nucleus and are required for the onset of transcription.

Early administration of methylprednisolone decreases apoptotic cell death after spinal cord injury

The purpose of this study is to evaluate, in an experimental model of spinal cord injury (SCI), the presence of apoptotic cell death after trauma and if early administration of a single bolus of methylprednisolone (MP) influences apoptosis in the zone of trauma and in adjacent spinal cord segments. For this study, a total of 96 adult female Wistar rats were subjected to spinal contusion at the T6-T8 level, producing immediate paraplegia. Forty-eight animals (treated group) received a single intraperitoneal injection of MP, at a dose of 30 mg/kg body weight, 10 minutes later. Cells undergoing apoptosis were detected by means of immunohistochemical labeling with the monoclonal antibody Apostain (anti-ssDNA MAb F7-26), in the injured spinal cord tissue, both in the zone of the lesion and in the adjacent spinal segments (rostral and caudal zones), 1, 4, 8, 24 and 72 hours and 1 week after injury. Apoptosis was detected in neurons and glial cells in the zone of the lesion 1 hour after trauma, with a pattern that showed no changes 4 hours later. Between 4 and 8 hours postinjury, the number of apoptotic cells increased, after which it decreased over the following days. In the adjacent spinal segments, apoptotic cells were detected 4 hours after trauma, and increased progressively over the remainder of the study, the number of apoptotic cells being similar in the lesion zone and in rostral and caudal zones one week after injury. When the group of MP-treated animals was considered, significant decreases in the number of apoptotic cells were detected in the lesion zone 24 hours after injury, and in the rostral and caudal zones, at 72 hours and at 1 week after trauma. These findings show that early administration of a single bolus of MP decreases apoptotic cell death after SCI, supporting the utility of MP in reducing secondary damage in injured spinal cord tissue.

Role of the p53 homologue fromDrosophila melanogasterin the maintenance of histone H3 acetylation and response to UV-light irradiation

It has been demonstrated that the human tumor suppressor p53 has an important role in modulating histone modifications after UV light irradiation. In this work we explored if the p53 Drosophila homologue has a similar role. Taking advantage of the existence of polytene chromosomes in the salivary glands of third instar larvae, we analyzed K9 and K14 H3 acetylation patterns in situ after UV irradiation of wild-type and Dmp53 null flies. As in human cells, after UV damage there is an increase in H3 acetylation in wild-type organisms. In Dmp53 mutant flies, this response is significantly affected at the K9 position. These results are similar to those found in human p53 mutant tumor cells with one interesting difference, only the basal H3 acetylation of K14 is reduced in Dmp53 mutant flies, while the basal H3-K9 acetylation is not affected. This work shows, that the presence of Dmp53 is necessary to maintain normal H3-K14 acetylation levels in Drosophila chromatin and that the function of p53 to maintaining histone modifications, is conserved in Drosophila and humans.

RNA polymerase II 140wimp mutant and mutations in the TFIIH subunit XPB differentially affect homeotic gene expression in Drosophila

Mutations in the XPB and XPD helicases of the DNA repair/transcription factor TFIIH are involved in several human genetic disorders. An unanswered problem concerning the complexity of the phenotype-genotype relationship is why mutations in individual subunits of TFIIH produce specific phenotypes and not many others. In order to investigate this question we tested whether mutations in the Drosophila XPB homolog, haywire (hay), would modify homeotic derepression phenotypes. In this work, we report that mutations in hay and in the 140-kDa subunit of the RNA polymerase II (RpII140wimp) act as dominant modifiers of the derepression phenotypes of the Sex combs reduced (Scr) and Ultrabithorax (Ubx) genes. The hay mutations only weakly suppress the Scr derepression phenotype caused by the Antp(Scx) mutation but not by Polycomb. In contrast, the RpII140wimp mutation strongly suppresses both Scr derepression phenotypes. In addition, the RpII140wimp also generates phenotypes indicative of loss of Ubx function. On the other hand, all the derepression homeotic phenotypes are sensitive to the generalized reduction of transcription levels when the flies are grown with actinomycin D. We also show that different promoter control regions have differential sensitivity to different hay alleles. All these results support that although TFIIH is a basal transcription factor, mutations in the subunit encoded by hay have specific effects in the transcription of some genes.

A new neovalve type in short bowel syndrome surgery

The objective of this study was to compare the clinical and analytical repercussion of a new type of intestinal valve -which can be used in both massive resections and right hemicolectomies requiring the elimination of the ileocecal valve- on two historical series of patients: one group with ileocolic resections and end-to-end anastomoses (EE), and one group with Ricotta valves. We compared 23 patients with ileocolic resection and end-to-end anastomosis, 15 with Ricotta's valve, and 20 patients with a new valve made with a small intestinal invagination. There were no statistically significant differences in baseline characteristics among patients. Patients with the new valve showed less relevant weight loss and fewer stools at 3 months and one year when compared to patients with Ricotta's valve, and particularly those with ileocolic resection. Moreover, with the new valve technique there was neither colonization of the ileal mucosa nor bacterial overgrowth. In conclusion, in massive intestinal resections and right hemicolectomies, including the ileocecal valve, the new valve technique would be of choice.

The transcriptional complexity of the TFIIH complex

Mutations in some subunits of the basal DNA repair and transcription factor II H (TFIIH) are involved in several human genetic disorders. Transcription factor II H interacts with a variety of factors during transcription, including nuclear receptors, tissue-specific transcription factors, chromatin remodeling complexes and RNA, suggesting that, in addition to its essential role in transcription initiation, it also participates as a regulatory factor. Interpretation of the phenotypes produced by mutations in TFIIH is complicated by the recent finding that TFIIH plays a role in RNA polymerase I (RNA Pol I)-mediated transcription. In vitro reconstituted systems and genetic analysis suggest two possible explanations for the transcriptional phenotypes of TFIIH mutations that are not mutually excluding. The first is that different sets of genes require different levels of transcription to maintain a wild-type phenotype. The second suggests that mutations in TFIIH produce specific phenotypes arising from differential interactions of this complex with different transcription regulatory factors.

Apoptosis is not correlated with the presence of CD57+ NK-cells in brain metastases

BACKGROUND

Cell apoptosis in solid tumours has been related to immunological attack by NK-cells. The purpose of the present study is to verify in the tissue of brain metastases a possible relationship among the degree of NK-cell infiltration and the number of apoptotic tumour cells.

METHODS

Twenty brain metastases whose tumour cells expressed CD95 (Fas/APO1) have been studied. NK-cells were identified by using the monoclonal antibody to CD57, and apoptotic tumour cells by means of the immunostain with the anti-ssDNA monoclonal antibody F7-26. The Spearman rank correlation test was used to study the relationship between the degree of CD57-NK-cell infiltration and the apoptosis labelling-index.

FINDINGS

Positivity to F7-26 was present in all tumour samples, but the number of immunostained cells showed a wide variability, with a mean apoptosis labelling-index of 11.48%. All the studied tumours showed CD57 immunostained cells, with a number that ranged between 4 and 20 per microscopical field at 200x (mean+/-standard deviation: 8.4+/-3.7). Statistical studies showed that there was no correlation between the number of CD57 immunostained NK-cells and the apoptosis labelling-index (p>0.05).

INTERPRETATION

These findings suggest that in brain metastases, apoptosis related to immune response is mainly mediated by activated tumour-infiltrating mononuclear cells other than CD57(+) NK-cells.

The Drosophila trithorax group gene tonalli (tna) interacts genetically with the Brahma remodeling complex and encodes an SP-RING finger protein

The trithorax group genes are required for positive regulation of homeotic gene function. The trithorax group gene brahma encodes a SWI2/SNF2 family ATPase that is a catalytic subunit of the Brm chromatin-remodeling complex. We identified the tonalli (tna) gene in Drosophila by genetic interactions with brahma. tna mutations suppress Polycomb phenotypes and tna is required for the proper expressions of the Antennapedia, Ultrabithorax and Sex combs reduced homeotic genes. The tna gene encodes at least two proteins, a large isoform (TnaA) and a short isoform (TnaB). The TnaA protein has an SP-RING Zn finger, conserved in proteins from organisms ranging from yeast to human and thought to be involved in the sumoylation of protein substrates. Besides the SP-RING finger, the TnaA protein also has extended homology with other eukaryotic proteins, including human proteins. We show that tna mutations also interact with mutations in additional subunits of the Brm complex, with mutations in subunits of the Mediator complex, and with mutations of the SWI2/SNF2 family ATPase gene kismet. We propose that Tna is involved in postranslational modification of transcription complexes.

A new peroxinectin-like gene preferentially expressed during oogenesis and early embryogenesis in Drosophila melanogaster

Several peroxidase isozymes have been described in Drosophila melanogaster. We describe a peroxinectin-like gene (Dpxt) in D. melanogaster. Peroxinectin is a cell-adhesive hemoperoxidase which binds superoxide dismutase and mediates blood cells attachment and spreading in the crayfish Pacifastacus leniusculus. The Dpxt predicted protein has a putative RGD-integrin binding tripeptide. The Dpxt mRNA is present in high amounts in late oogenesis and in early embryogenesis until the cellular blastoderm stage. It is virtually absent at other stages of the Drosophila life cycle, suggesting that Dpxt function is restricted to the early stages of fly development.

Growth-inhibiting effects of intralesional docetaxel and paclitaxel on an experimental model of malignant neuroectodermal tumor

Taxoids are effective agents against a wide variety of tumors, but their effectiveness on neuroectodermal tumors is not well-known. For this reason we have carried out an experimental study on the effect of intratumoral administration of docetaxel (DC) and paclitaxel (PC) on tumor growth, using a murine model of malignant neuroectodermal tumor. The results showed a delay in tumor growth in animals treated with PC compared with controls (dose of 5 mg/kg, three times per week every other day, forming a cycle; three cycles were completed with a break of a week between each cycle). The total dose administered to each animal was 45 mg/kg. When DC was administered, the results showed distinct tumor growth inhibition and tumor regression in 80% of animals (intratumoral administration at a dose of 5 mg/kg, three times per week every other day forming a cycle; three cycles were completed with a break of a week between each cycle). The total dose administered to each animal was 20 mg/kg. These results suggest the utility of taxoids, mainly DC, by intralesional administration, on malignant tumors of the nervous system.

DNA repair and transcriptional effects of mutations in TFIIH in Drosophila development

Mutations in XPB and XPD TFIIH helicases have been related with three hereditary human disorders: xeroderma pigmentosum, Cockayne syndrome, and trichothiodystrophy. The dual role of TFIIH in DNA repair and transcription makes it difficult to discern which of the mutant TFIIH phenotypes is due to defects in any of these different processes. We used haywire (hay), the Drosophila XPB homolog, to dissect this problem. Our results show that when hay dosage is affected, the fly shows defects in structures that require high levels of transcription. We found a genetic interaction between hay and cdk7, and we propose that some of these phenotypes are due to transcriptional deficiencies. We also found more apoptotic cells in imaginal discs and in the CNS of hay mutant flies than in wild-type flies. Because this abnormal level of apoptosis was not detected in cdk7 flies, this phenotype could be related to defects in DNA repair. In addition the apoptosis induced by p53 Drosophila homolog (Dmp53) is suppressed in heterozygous hay flies.

Prognostic significance of tumor-enhancement and angiogenesis in oligodendroglioma

OBJECTIVE

To study the prognostic significance of angiogenesis and enhancement on contrast-enhanced computerized tomography (CT) in oligodendrogliomas.

MATERIAL AND METHODS

CD34 immunostaining was employed in samples of 26 low-grade oligodendrogliomas from patients treated by extensive resection and radiotherapy to determine the tumor angiogenesis index (TAI), calculated by measuring the immunostained endothelial surface area, in microm(2), per 1000 tumor cells. Preoperative CT scan was evaluated in each case, and the absence or presence of tumor enhancement after contrast administration was recorded. Survival was analyzed and statistically compared for subgroups of patients with lesions in which the TAI was less than or greater than 15, and for subgroups of patients having tumors showing presence or absence of enhancement on contrast-enhanced CT.

RESULTS

Survival of patients with tumors showing a TAI of less than 15 was 100% and 71% at 5 and 10 years, respectively, vs a survival of 50% and 0% for patients showing a TAI of more than 15 (P < 0.05). The 14 patients whose tumors showed enhancement in preoperative contrast-enhanced CT had 5- and 10-year survival rates of 57% and 14%, respectively, vs 100% and 83% for the 12 patients whose tumors presented no enhancement (P < 0.05). Moreover, 79% of the tumors showing contrast enhancement had a TAI greater than 15, while 92% of those exhibiting no enhancement had a TAI of less than 15.

CONCLUSION

These findings indicate a relationship between enhancement on preoperative CT scan and endothelial surface area in oligodendrogliomas, and suggest that this enhancement and the TAI may be considered angiogenesis-related factors with similar prognostic significance in terms of survival.

From noxiustoxin to scorpine and possible transgenic mosquitoes resistant to malaria

Scorpion venom contains different types of peptides toxic to a variety of organisms whose molecular targets have been described as mainly ion-channels of excitable cells where they cause impairment of function. Based on mouse, cricket, and crustacean bioassays, specific toxins for each group of animals have been found. Chromatographic techniques were used to isolate and chemically characterize these peptides. One of the best-studied peptides is noxiustoxin, a 39-amino acid residue-long peptide specific for K(+)-channels. Hadrurin is another scorpion venom peptide whose activity was shown to be bactericidal to a variety of species. Structural similarities of a newly discovered peptide (scorpine) with those of defensins and cecropins showed that scorpion venom contains peptides toxic to microorganisms and malaria parasites. Scorpine was shown to disrupt the sporogonic development of Plasmodium berghei. Using this system as a model for malaria, we introduced the gene of scorpine into a vector for generation of transgenic flies resistant to the infection by Plasmodium. The final aim of this work is to incorporate this gene under the promoter of proteolytic enzymes of digestive tract of mosquitoes for synthesis and liberation of toxic peptide(s) into stomach of freshly fed mosquitoes potentially carrying Plasmodium gametes. In this manner, a putative transgenic mosquito with these characteristics would secrete a toxic peptide with digestive enzymes into midgut, impairing proper development of Plasmodium, hence controlling malaria, one of the most important tropical diseases worldwide.

Antitumor effect of TNP-470 is not associated to decrease of angiogenesis in an experimental malignant neuroectodermic tumor

The hypothesis that tumor growth depends on neovascularization has been broadly used in oncology research. TNP-470 is a fumagillin synthetic analog that is isolated from Aspergillus fumigatus, and experimental studies suggested that it shows antitumor effect mediated by its strong antiangiogenic effect. Because limited experience exists about the antitumoral effect of TNP-470 in cerebral tumors, we have carried out a study in order to evaluate the effect of TNP-470 on tumor growth and the vascular area in an experimental malignant neuroectodermic tumor growing in the subcutaneous space of immunocompetent Wistar rats. Our results showed a significant tumor growth inhibition in animals treated with TNP-470 when compared to those in the control group (intratumoral injections were administered in 30 mg/kg dose, three times a week on alternate days during four consecutive weeks). Since the quantitative analysis of tumor vascular parameters--number of microvessels and total intratumor vascular area--in the experimental groups did not show significant statistical differences, we conclude that TNP-470 has a significant antitumor effect on our neuroectodermic tumor, but this effect is mediated by other antineoplastic mechanisms that are independent of its previously described angiostatic capacity.

Molecular characterization and developmental expression of the TFIIH factor p62 gene from Drosophila melanogaster: effects on the UV light sensitivity of a p62 mutant fly

TFIIH is a multiprotein complex that has a central role in the RNA pol II mediated transcription, in DNA repair and in the control of the cell cycle. Mutations in some components of TFIIH are associated with three hereditary human syndromes: xeroderma pigmentosum (XP), Cockayne syndrome (CS) and trichothiodystrophy (TTD). The p62 protein is a structural component of the TFIIH core and no syndromes have been identified up to date by mutations in this human gene. In this work we report the molecular and genetic characterization of the Drosophila melanogaster p62 gene (Dmp62). The Dmp62 gene product shows high identity with its human and mouse homologues. Using computer analysis we identified several common motifs in the p62 proteins from different organisms, suggesting that these motifs could be involved in possible protein-protein interactions within the TFIIH complex or with other transcription and DNA repair factors. The Dmp62 transcript is expressed at similar levels throughout development, although there is a significant increase of the transcript level during the late embryogenesis and in the adult male. The analysis of a Drosophila line with a P-element enhancer trap insertion at the Dmp62 5'-UTR that directs the lac-Z expression from the Dmp62 promoter, showed a high level of expression in the gut, the testis and the pericardial cells. A P-element that disrupts the Dmp62 gene (Dmp62mut) produces early embryo lethality in homozygous flies. Heterozygous Dmp62mut larvae are more sensitive to UV light irradiation, and those individuals that are able to develop into adults have severe abdominal cuticular damage after UV light irradiation.