The paralogues MAGOH and MAGOHB are oncogenic factors in high-grade gliomas and safeguard the splicing of cell division and cell cycle genes

The exon junction complex (EJC) plays key roles throughout the lifespan of RNA and is particularly relevant in the nervous system. We investigated the roles of two EJC members, the paralogs MAGOH and MAGOHB, with respect to brain tumour development. High MAGOH/MAGOHB expression was observed in 14 tumour types; glioblastoma (GBM) showed the greatest difference compared to normal tissue. Increased MAGOH/MAGOHB expression was associated with poor prognosis in glioma patients, while knockdown of MAGOH/MAGOHB affected different cancer phenotypes. Reduced MAGOH/MAGOHB expression in GBM cells caused alterations in the splicing profile, including re-splicing and skipping of multiple exons. The binding profiles of EJC proteins indicated that exons affected by MAGOH/MAGOHB knockdown accumulated fewer complexes on average, providing a possible explanation for their sensitivity to MAGOH/MAGOHB knockdown. Transcripts (genes) showing alterations in the splicing profile are mainly implicated in cell division, cell cycle, splicing, and translation. We propose that high MAGOH/MAGOHB levels are required to safeguard the splicing of genes in high demand in scenarios requiring increased cell proliferation (brain development and GBM growth), ensuring efficient cell division, cell cycle regulation, and gene expression (splicing and translation). Since differentiated neuronal cells do not require increased MAGOH/MAGOHB expression, targeting these paralogs is a potential option for treating GBM.

U1A is a positive regulator of the expression of heterologous and cellular genes involved in cell proliferation and migration

Here, we show that direct recruitment of U1A to target transcripts can increase gene expression. This is a new regulatory role, in addition to previous knowledge showing that U1A decreases the levels of U1A mRNA and other specific targets. In fact, genome-wide, U1A more often increases rather than represses gene expression and many U1A-upregulated transcripts are directly bound by U1A according to individual nucleotide resolution crosslinking and immunoprecipitation (iCLIP) studies. Interestingly, U1A-mediated positive regulation can be transferred to a heterologous system for biotechnological purposes. Finally, U1A-bound genes are enriched for those involved in cell cycle and adhesion. In agreement with this, higher U1A mRNA expression associates with lower disease-free survival and overall survival in many cancer types, and U1A mRNA levels positively correlate with those of some oncogenes involved in cell proliferation. Accordingly, U1A depletion leads to decreased expression of these genes and the migration-related gene CCN2/CTGF, which shows the strongest regulation by U1A. A decrease in U1A causes a strong drop in CCN2 expression and CTGF secretion and defects in the expression of CTGF EMT targets, cell migration, and proliferation. These results support U1A as a putative therapeutic target for cancer treatment. In addition, U1A-binding sequences should be considered in biotechnological applications.

Exon Junction Complex Shapes the Transcriptome by Repressing Recursive Splicing

Recursive splicing (RS) starts by defining an "RS-exon," which is then spliced to the preceding exon, thus creating a recursive 5' splice site (RS-5ss). Previous studies focused on cryptic RS-exons, and now we find that the exon junction complex (EJC) represses RS of hundreds of annotated, mainly constitutive RS-exons. The core EJC factors, and the peripheral factors PNN and RNPS1, maintain RS-exon inclusion by repressing spliceosomal assembly on RS-5ss. The EJC also blocks 5ss located near exon-exon junctions, thus repressing inclusion of cryptic microexons. The prevalence of annotated RS-exons is high in deuterostomes, while the cryptic RS-exons are more prevalent in Drosophila, where EJC appears less capable of repressing RS. Notably, incomplete repression of RS also contributes to physiological alternative splicing of several human RS-exons. Finally, haploinsufficiency of the EJC factor Magoh in mice is associated with skipping of RS-exons in the brain, with relevance to the microcephaly phenotype and human diseases.

Increased in vivo inhibition of gene expression by combining RNA interference and U1 inhibition

Inhibition of gene expression can be achieved with RNA interference (RNAi) or U1 small nuclear RNA—snRNA—interference (U1i). U1i is based on U1 inhibitors (U1in), U1 snRNA molecules modified to inhibit polyadenylation of a target pre-mRNA. In culture, we have shown that the combination of RNAi and U1i results in stronger inhibition of reporter or endogenous genes than that obtained using either of the techniques alone. We have now used these techniques to inhibit gene expression in mice. We show that U1ins can induce strong inhibition of the expression of target genes in vivo. Furthermore, combining U1i and RNAi results in synergistic inhibitions also in mice. This is shown for the inhibition of hepatitis B virus (HBV) sequences or endogenous Notch1. Surprisingly, inhibition obtained by combining a U1in and a RNAi mediator is higher than that obtained by combining two U1ins or two RNAi mediators. Our results suggest that RNAi and U1i cooperate by unknown mechanisms to result in synergistic inhibitions. Analysis of toxicity and specificity indicates that expression of U1i inhibitors is safe. Therefore, we believe that the combination of RNAi and U1i will be a good option to block damaging endogenous genes, HBV and other infectious agents in vivo.

A prospective study of cutaneous adverse events induced by low-dose alpha-interferon treatment for malignant melanoma

INTRODUCTION

alpha-Interferon is associated with numerous cutaneous side effects, but the accurate incidence of these complications is not clearly known.

OBJECTIVES

A prospective study was designed to evaluate the incidence and clinical pattern of cutaneous side effects in a cohort of patients receiving adjuvant therapy with low-dose interferon for malignant melanoma.

MATERIAL AND METHODS

A cohort of 33 patients with stage IIA and IIB melanoma treated with low-dose alpha-interferon (3 MIU 3 times a week for 18 months) were prospectively enrolled in a single-center study. The patients responded to a questionnaire on their medical history and were systematically examined for any cutaneous lesions before treatment and every 3 months afterwards.

RESULTS

29/33 patients (87%) experienced 1 or more cutaneous side effects. The most frequent was hair loss and occurred in 16 cases (48.4%). Hair discoloration was noted in 6 cases (18%). Eczematous reactions at injection sites or at remote sites were observed in 13 patients (39%). Pruritus occurred in 10 cases (30%). Xerostomia, Raynaud's phenomenon or livedo reticularis were observed in 10 patients, associated with an increase in circulating autoantibody titer in 2 cases. Some rare side effects were observed: urticaria (1 case) or angioedema (1 case), worsening of preexisting seborrheic dermatitis (3 cases), herpetic recurrence (2 cases), pityriasis versicolor (1 case), worsening of recurrent buccal aphthous ulcer (1 case) and vitiligo (1 case).

CONCLUSION

Cutaneous adverse events during adjuvant immunotherapy of melanoma with low-dose alpha-interferon seem to be frequent but do not result in treatment discontinuation. A good awareness of these side effects may be useful for a more accurate survey and clinical management of patients receiving this treatment.

Management of biliary duct confluence injuries produced by hepatic hydatidosis

From 1978 to 1999 a total of 850 patients underwent surgical treatment for hydatid disease of the liver at our surgical department. Biliary duct confluence injuries produced by hepatic hydatidosis (HH) were founded in six patients (0.7%). Surgical intervention was undertaken to relieve the obstructive jaundice and clinical manifestations of cholangitis and to treat the hydatid cyst. A partially open cystopericystectomy technique was used in three patients with a double bilioenteric Roux-en-Y reconstruction. The remaining three patients (two with prehepatic portal hypertension and one with triple hepatic duct confluence) were subjected to a cystojejunostomy. There were no hospital deaths. Two cases of anastomotic leakage following a high bilioenteric anastomosis occurred but did not require surgical treatment. During the follow-up (5-19 years) one patient suffered local recurrence of the hydatid disease 7 years after cystojejunostomy. The site of intrahepatic biliary and vascular involvement, the presence of biliary duct anomalies, and the presence of portal hypertension are decisive factors when choosing the "ideal" procedure for reconstruction. Conservative surgical approaches (partial cystectomy and cystojejunostomy) are the treatments of choice. Radical surgery is often a serious matter.

[Ipsilateral frontal and contralateral cerebellar diaschisis related to unilateral pontine infarction]

A right frontal and left cerebellar diaschisis, resulting from a right pontine infarction, is reported in a patient with complete left hemiplegia. Magnetic resonance imaging and CT scan supported the existence of the pontine infarction. The SPECT-HMPAO-99mTc showed a relative hypoactivity in the right frontal lobe and left cerebellar hemisphere.