RNase H-dependent DNA thresholder modulated by cancer marker concentration.

Threshold antisense oligonucleotide constructs were designed to cleave mRNA within different biomarker concentrations. The mRNA cleavage is activated by 2.6, 7.5 or 39.5 nM of biomarker depending on the construct design. The constructs can be used to differentiate cancer from normal cells by the level of oncogene expression followed by silencing of a targeted gene.

Thresholding DNA Nanomachine as a Highly Cooperative and Efficient Enzyme-Like System for Controlled RNA Cleavage.

Therapeutic nucleic acid agents (TNA) can be activated by a marker RNA sequence followed by initiation of targeted RNA cleavage. This property can be used in conditional cell suppression, e. g., cancer marker-dependent cell death. However, healthy cells often express lower levels of cancer markers, thus jeopardizing TNA activation exclusively in cancer cells. Earlier, we developed a conditionally activated split deoxyribozyme construct (DNA thresholder or DTh) that can be activated by high but not by low concentrations of cancer markers. It's activity, however, was suppressed by very high marker concentrations. Herein, we combine the DTh functional units in a single DNA association (Thresholding DNA nanomachine or Th-DNM). Th-DNM maintains a high level of RNA cleavage activity in the presence of marker concentrations above the threshold level. Th-DNM differentiated fully complementary miR17 markers sequence from double base mismatched miR-20. Th-DNM can become a building block of DNA nanorobots for cancer treatment.

Binary Antisense Oligonucleotide Agent for Cancer Marker-Dependent Degradation of Targeted RNA.

Antisense oligonucleotide technology is one of the most successful gene therapy (GT) approaches. However, low selectivity of antisense agents limits their application as anticancer drugs. To achieve activation of antisense agent selectively in cancer cells, herein, we propose the concept of binary antisense oligonucleotide (biASO) agent. biASO recognizes an RNA sequence of a gene associated with cancer development (marker) and then activates RNase H-dependent cleavage of a targeted messenger RNA. biASO was optimized to produce only the background cleavage of the targeted RNA in the absence of the activator. The approach lays the foundation for the development of highly selective and efficient GT agents.

RNA-Cleaving DNA Thresholder Controlled by Concentrations of miRNA Cancer Marker.

Oligonucleotide gene therapy (OGT) agents suppress specific mRNAs in cells and thus reduce the expression of targeted genes. The ability to unambiguously distinguish cancer from healthy cells can solve the low selectivity problem of OGT agents. Cancer RNA markers are expressed in both healthy and cancer cells with a higher expression level in cancer cells. We have designed a DNA-based construct, named DNA thresholder (DTh) that cleaves targeted RNA only at high concentrations of cancer marker RNA and demonstrates low cleavage activity at low marker concentrations. The RNA-cleaving activity can be adjusted within one order of magnitude of the cancer marker RNA concentration by simply redesigning DTh. Importantly, DTh recognizes cancer marker RNA, while cleaving targeted RNA; this offers a possibility to suppress vital genes exclusively in cancer cells, thus triggering their death. DTh is a prototype of computation-inspired molecular device for controlling gene expression and cancer treatment.

Rifaximin in nonalcoholic fatty liver disease: hit multiple targets with a single shot.

BACKGROUND/AIMS: The pathogenesis of nonalcoholic fatty liver disease (NAFLD) may include increased insulin resistance, upregulation of proinflammatory cytokines, lipopolysaccharide, and BMI. Rifaximin is a minimally absorbable antibiotic that might act against a broad spectrum of gut bacteria. This study aimed to investigate the effects of rifaximin on NAFLD. PATIENTS AND METHODS: Fifty participants with biopsy-proven nonalcoholic steatohepatitis (NASH) were registered in this multicentric, double-blind, randomized, placebo-controlled study. BMI, alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, lipid profile, serum endotoxin, homeostatic model assessment, toll-like receptor-4, interleukin-10 (IL-10), IL-6, tumor necrosis factor-α, and cytokeratin-18 (CK-18) levels were evaluated at baseline and at 1, 3, and 6 months of rifaximin therapy (1100 mg/day). RESULTS: Patients were randomized into two groups (rifaximin group; n=25 and placebo group; n=25). After 6 months of rifaximin therapy, patients with NASH showed a significant reduction in homeostatic model assessment, alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, endotoxin, toll-like receptor-4, IL-6, tumor necrosis factor-α, CK-18, and NAFLD-liver fat score (all P<0.05), but no changes in the lipid profile; moreover, there was a mild nonstatistically significant reduction of BMI. However, in the placebo group, there was no significant difference in these variables at baseline and after therapy. CONCLUSION: Rifaximin therapy appears to be effective and safe in modifying NASH through reduction of serum endotoxin and improvement of insulin resistance, proinflammatory cytokines, CK-18, and NAFLD-liver fat score.

New predictive factors of poor response to therapy in autoimmune hepatitis: role of mean platelet volume.

BACKGROUND AND OBJECTIVES: The response to immunosuppressive therapy in autoimmune hepatitis (AIH) is a matter of debate. The aim of this work is to identify the histological, biochemical, and clinical predictive factors of incomplete response/treatment failure to the standard treatment (prednisone with or without azathioprine) in a well-characterized series of AIH Egyptian patients. PATIENTS AND METHODS: Of 49 AIH patients, only 36 patients completed this retrospective cohort study. The immunological, biochemical, histopathological, and clinical characteristics of patients were evaluated at diagnosis and during follow-up. RESULTS: Patients were classified into two groups; group A showed a complete response to therapy (n=22; 61%) and group B showed partial response/treatment failure (n=14; 39%). In a multivariate analysis, we observed that age at diagnosis up to 22 years [odds ratio (OR): 23.22; confidence interval (CI): 3.978-135.549; P<0.001], serum albumin up to 3.2 g/dl (OR: 5.36; CI: 1.237-23.209; P=0.025), mean platelet volume (MPV) of at least 10.75 fl (OR: 16.5; CI: 3.093-88.037; P<0.001), and presence of cirrhosis at diagnosis (OR: 8.44; CI: 1.682-42.392; P=0.001) were independent variables that can predict partial response/treatment failure. MPV correlated positively with stages of fibrosis/cirrhosis and grades of activity in liver biopsy at diagnosis and correlated inversely with serum albumin and age at presentation. During therapy, group B showed a fluctuation in MPV levels, however, group A showed a progressive decline until the end point. CONCLUSION: Our study confirmed that younger age, hypoalbuminemia, increased MPV, and cirrhosis at diagnosis were all independent predictors of incomplete response/treatment failure in AIH patients. MPV may reflect the response to therapy.