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.

Joint health and functional ability in children with haemophilia who receive intensive replacement therapy

Joint physical examination is an important outcome in haemophilia; however its relationship with functional ability is not well established in children with intensive replacement therapy. Boys aged 4-16 years were recruited from two European and three North American treatment centres. Joint physical structure and function was measured with the Haemophilia Joint Health Score (HJHS) while functional ability was measured with the revised Childhood Health Assessment Questionnaire (CHAQ₃₈. Two haemophilia-specific domains were created by selecting items of the CHAQ₃₈ that cover haemophilia-specific problems. Associations between CHAQ, HJHS, cumulative number of haemarthroses and age were assessed. A total of 226 subjects - mean 10.8 years old (SD 3.8) - participated; the majority (68%) had severe haemophilia. Most severe patients (91%) were on prophylactic treatment. Lifetime number of haemarthroses [median=5; interquartile range (IQR)=1-12] and total HJHS (median = 5; IQR=1-12) correlated strongly (ρ = 0.51). Total HJHS did not correlate with age and only weakly (ρ=-0.19) with functional ability scores (median=0; IQR=-0.06-0). Overall, haemarthroses were reported most frequently in the ankles. Detailed analysis of ankle joint health scores revealed moderate associations (ρ=0.3-0.5) of strength, gait and atrophy with lower extremity tasks (e.g. stair climbing). In this population, HJHS summating six joints did not perform as well as individual joint scores, however, certain elements of ankle impairment, specifically muscle strength, atrophy and gait associated significantly with functional loss in lower extremity activities. Mild abnormalities in ankle assessment by HJHS may lead to functional loss. Therefore, ankle joints may warrant special attention in the follow up of these children.

Liver dysfunction related to hepatitis B and C in patients with inflammatory bowel disease treated with immunosuppressive therapy

BACKGROUND

There is no information about the frequency of liver dysfunction in patients with inflammatory bowel disease (IBD) treated with immunosuppressants and infected with hepatitis B (HBV) and/or C virus (HCV).

AIM

To assess the influence of immunosuppressants on the course of HBV and HCV infection in IBD.

METHODS

Patients with IBD with HBV and/or HCV infection from 19 Spanish hospitals were included. Clinical records were reviewed for the type of immunosuppressant used, treatment duration, liver function tests and viral markers before, during and after each immunosuppressant. Logistic and Cox regression analysis were used to identify predictors of outcome.

RESULTS

162 patients were included; 104 had HBV markers (25 HBsAg positive) and 74 had HCV markers (51 HCV-RNA positive), and 16 patients had markers of both infections. Liver dysfunction was observed in 9 of 25 HBsAg positive patients (36%), 6 of whom developed hepatic failure. Liver dysfunction in HCV was observed in 8 of 51 HCV-RNA positive patients (15.7%), and only one developed hepatic failure. The frequency and severity of liver dysfunction was significantly higher in HBV-infected patients than in HCV-infected patients (p=0.045 and p=0.049, respectively). Treatment with ≥2 immunosuppressants was an independent predictor of HBV reactivation (OR 8.75; 95% CI 1.16 to 65.66). The majority of patients without reactivation received only one immunosuppressant for a short period and/or prophylactic antiviral treatment. No definite HBV reactivations were found in anti-HBc positive patients lacking HBsAg.

CONCLUSION

Liver dysfunction in patients with IBD treated with immunosuppressants is more frequent and severe in those with HBV than in HCV carriers and is associated with combined immunosuppression.

Combination of RNA interference and U1 inhibition leads to increased inhibition of gene expression

RNA interference (RNAi) has been revolutionary for the specific inhibition of gene expression. However, the application of RNAi has been hampered by the fact that many siRNAs induce dose-dependent unwanted secondary effects. Therefore, new methods to increase inhibition of gene expression with low doses of inhibitors are required. We have tested the combination of RNAi and U1i (U1 small nuclear RNA—snRNA—interference). U1i is based on U1 inhibitors (U1in), U1 snRNA molecules modified to target a pre-mRNA and inhibit its gene expression by blocking nuclear polyadenylation. The combination of RNAi and U1i resulted in stronger inhibition of reporter or endogenous genes than that obtained using either of the techniques alone. The increased inhibition observed is stable over time and allows higher inhibition than the best obtained with either of the inhibitors alone even with decreased doses of the inhibitors. We believe that the combination of RNAi and U1i will be of interest when higher inhibition is required or when potent inhibitors are not available. Also, the combination of these techniques would allow functional inhibition with a decreased dose of inhibitors, avoiding toxicity due to dose-dependent unwanted effects.

Consensus on the treatment of pancreatic cancer in Spain

Pancreatic cancer (PC) represents one of the greatest oncological challenges of our century, due to its high mortality and incidence. A group of Spanish experts in PC treatment reviewed data available on different therapeutic combinations and established consensus on what would be the best strategy in PC management, depending on the stage of the disease. Surgery with complete resection may produce 5-year survival rates of 18-24%, but definitive control is still precarious. In the absence of consensus, the best evidence suggests that adjuvant chemotherapy with gemcitabine for 6 months using the CONKO-001 regime is the treatment of choice after resection of PC for patients with acceptable functional status. This group recommends chemoradiotherapy (CT-RT) in patients with factors for poor loco-regional prognosis. However, chemotherapy is an option for the treatment of locally advanced PC in patients with good general status and in the absence of metastatic disease the recommended treatment is CT-RT followed by gemcitabine-based chemotherapy. A period of chemotherapy followed by consolidation CT-RT may be appropriate, as it allows selection of patients with locally advanced disease who may benefit most from combined treatment. Erlotinib combined with gemcitabine shows significant survival improvement in PC and must be considered an option in the first-line treatment of advanced and metastatic PC. The gemcitabine-erlotinib combination is proposed as the standard treatment for metastatic PC in patients with PS=/>2. In patients with PS<2, gemcitabine-erlotinib is recommended as the first-line treatment option, supported by a maximum degree of evidence, without ruling out other options, such as gemcitabine-oxaliplatin, gemcitabine-capecitabine or gemcitabine alone.

Pharmacogenetic analysis of TS and UGT1A polymorphisms predictive for response and toxicity in Spanish patients with advanced colorectal cancer treated with first-line irinotecan and 5-fluorouracil

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Background: The possible role of uridine diphosphate-glucuronosyltransferase 1A (UGT1A) and Thymidylate Synthase (TS) gene polymorphisms in predicting toxicity and outcomes in irinotecan/ 5-Fluorouracil (5FU)-treated patients is still controversial. The aim of this work was to determine whether UGT1A1, UGT1A7, and UGT1A9 as well as TS polymorphisms affect toxicities and/or outcomes of Spanish patients with advanced colorectal cancer (mCRC) Methods: A total of 149 patients with mCRC were treated either with weekly irinotecan plus high-dose 5FU (FUIRI) or biweekly irinotecan plus 5FU/Leucovorin (FOLFIRI) as first-line chemotherapy (Aranda E; Ann Oncol. 2008 Aug 20). Genomic DNA was extracted from peripheral blood and genotyped using allelic discrimination and direct sequencing. Chi-square test, Fisher's exact test and logistic regression were used to study the association of genotypes with toxicity and response. Log rank and cox regression were used in survival analysis. All statistical tests were two-sided. Results: According to TS 5’TRP genotypes, 79.3% of the 2R/2R patients responded to therapy while only 52.5% of 2R/3R or 3R/3R patients do so (HR=3.5; 95% CI=1.3- 9.1; p=0.009). TS genotypes were not associated with toxicity. UGT1A1*28 TA7/TA7 genotype was clearly associated with severe toxicity (HR=12.7; 95% CI=3.1–51.3; p=0.001) and diarrhea (HR=4; 95% CI=1.3–12; p=0.016) when compared to TA6/TA7 and TA6/TA6 genotypes. These patients also experienced more severe neutropenia (40% vs. 18.8%, p=0.087) and more frequent dose reductions (53.3% vs. 38.1%, p=ns). UGT1A7*3/*3 and UGT1A9–118(dT)9/9 were associated with severe diarrhea (50% vs. 27% p=0.032 and 43% vs. 23% p=0.012). When all non-favourable genotypes (TA7/TA7, *3/*3 and 9/9) were taken into account, there was a statistically significant association with severe diarrhea (HR=4.5; 95% CI 1.3–16.3; p=0.021), neutropenia (HR=3.5; 95% CI=1–12.7; p=0.047) and both (HR=12.4; 95% CI=2.8–54.2; p=0.001). Conclusions: Our data clearly link UGT1A genotypes with irinotecan-related severe toxicity. TS 5’TRP genotypes are predictive of response to irinotecan/5FU first-line chemotherapy.

No significant financial relationships to disclose.

In vitro-acquired resistance gene expression profile and in vivo response to oxaliplatin-based treatment

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Background: Resistance to oxaliplatin is one of the main problems of colorectal cancer (CRC) treatment success. It is not clear if intrinsic and acquired resistance processes are developed by related mechanisms. In a previous work (Martinez-Cardús et al. Mol Cancer Ther, January 2009), we determined a profile of oxaliplatin-acquired resistance related genes by using an in vitro model. In the present work, we analyzed this genetic profile in paraffin-embedded primary adenocarcinomas from CRC patients treated with oxaliplatin-fluoropyrimidine. mRNA expression data was correlated with response rate and time to progression (TTP) in order to determine the role of these genes as markers of resistance to oxaliplatin-based treatment. Material and Method: mRNA levels were analyzed by using Real Time PCR. β-actin and 18s were used as housekeeping genes and, as a reference sample, we used commercial pool of mRNA from different human tumours. Chi- square and Fisher test were used in order to value differences in response rate to treatment. TTP was studied by using Kaplan Meyer curves and Log rank test. Median and percentile 33 and 66 were used as threshold values to determine both high and low expression level groups for each gene analyzed. We considered statistically significant a two-sided p-value lower than 0.05. Results: Forty-four advanced CRC patients treated with fluoropyrimidine plus oxaliplatin were analyzed. 54.5% of them were males; primary tumour was localized in colon in a 65.9% of cases. According to qRT-PCR analysis, the in vitro oxaliplatin acquired resistance related genes could be detected in the tumours but the expression of any of them correlated significantly with in vivo resistance to oxaliplatin-based treatment by using the three different threshold values to define groups. Conclusions: According to our results, these genes could not be used as markers of resistance to oxaliplatin-based treatment in non-treated tumours. Thereby, oxaliplatin resistance acquisition genes seems not to be involved in intrinsic drug resistance probably due to the fact that acquired and intrinsic oxaliplatin resistance are not related mechanisms. Further studies to typify oxaliplatin intrinsic resistance potential markers are guaranteed.

No significant financial relationships to disclose.

[Pneumomediastinum and extensive subcutaneous emphysema after normal labor]

Spontaneous pneumomediastinum associated with subcutaneous emphysema is a rare, though life-threatening, complication of late pregnancy and labor. We report the case of a primipara who, after undergoing normal labor and delivery of a normal-weight baby, developed pneumomediastinum and extensive subcutaneous emphysema with significant symptoms within minutes of delivery. This peripartum complication is usually self-limiting when the aggravating factors are no louguer present. Management includes strict monitoring of the patient and conservative treatment of symptoms.