Innovative Tumor Tissue Dissection Tool for Molecular Oncology Diagnostics

Formalin-fixed, paraffin-embedded (FFPE) tissue is the most commonly used material for tumor molecular profiling, therapy selection, and prognostication. Tumor tissue enrichment by tissue dissection is highly recommended to generate quality data reproducibly for use in downstream assays, such as real-time PCR and next-generation sequencing. The aim of this study was to evaluate the performance of the automated tissue dissection tool AVENIO Millisect System compared with a manual dissection method using 18 FFPE tissue specimens. The study assessed performance of these two methods with paraffinized and deparaffinized sections at 5- and 10-μm thickness as well as at low (5% to 10%) and high (>50%) tumor content. In addition, compatibility with various nucleic acid and protein extraction methods was assessed. Overall, dissection by Millisect resulted in statistically significantly higher yields of nucleic acids and protein compared with manual dissection (P = 0.00524). In downstream analysis on a statistically nonpowered sample set, EGFR mutation testing by PCR led to highly concordant results, and next-generation sequencing testing yielded significantly higher allelic frequencies when tissue was dissected by Millisect compared with manual scraping, demonstrating noninferiority of the automated method. In summary, the AVENIO Millisect System may replace manual labor and support automation of FFPE tumor tissue workflows in clinical molecular laboratories with high testing volumes with adequate validation.

Detection of in vivo hepatitis B virus surface antigen mutations-A comparison of four routine screening assays

An important requirement for a state-of-the-art hepatitis B surface antigen (HBsAg) screening assay is reliable detection of mutated HBsAg. Currently, there is a striking shortage of data regarding the detection rates of in vivo HBsAg mutations for these clinically important assays. Therefore, we compared the detection rates of four commercial HBsAg screening assays using a global cohort of 1553 patients from four continents with known HBV genotypes. These samples, which represent the broadest spectrum of known and novel HBsAg major hydrophilic region (MHR) mutations to date, were analyzed for the presence of HBsAg using the Roche Elecsys^® HBsAg II Qualitative, Siemens ADVIA Centaur XP HBsAg II, Abbott Architect HBsAg Qualitative II and DiaSorin Liaison^® HBsAg Qualitative assays, respectively. Of the 1553 samples, 1391 samples could be sequenced; of these, 1013 (72.8%) carried at least one of the 345 currently known amino acid substitutions (distinct HBsAg mutation) in the HBsAg MHR. All 1553 patient samples were positive for HBsAg using the Elecsys^® HBsAg II Qual assay, with a sensitivity (95% confidence interval) of 99.94% (99.64%-100%), followed by the Abbott Architect 99.81% (99.44%-99.96%), Siemens ADVIA 99.81% (99.44%-99.96%) and DiaSorin Liaison^® 99.36% (98.82%-99.69%) assays, respectively. Our results indicate that the Elecsys^® HBsAg II Qual assay exhibits the highest sensitivity among the commercial HBsAg screening assays, and demonstrate that its capacity to detect HBV infection is not compromised by HBsAg MHR mutants.

Treatment of experimental murine colitis with CD40 antisense oligonucleotides delivered in amphoteric liposomes

BACKGROUND AND AIMS

CD40-CD40L interactions appear to play an important role in the pathogenesis of experimental colitis. We tested the effect and investigated the underlying mechanism of action of systemically administered antisense oligonucleotide (ASO) targeting CD40 formulated in amphoteric liposomes (nov038/CD40). The charge characteristics of the amphoteric liposomes (anionic surface charge at physiological pH that becomes cationic at low pH), facilitate efficient sequestration of the ASO inside the liposomes at low pH and the direction of the carriers towards macrophages and dendritic cells under physiological conditions.

METHODS

Colitis was induced in Balb/c mice using 2,4,6-Trinitrobenzene sulphonic acid (TNBS) and treated with nov038/CD40. Disease was monitored by body weight, histology, cytokine profiling and changes in immune cell populations. CD40 expression on different cell subsets was analyzed by flow cytometry. An antigen challenge model was used to determine neoimmunity under CD40 modulation.

RESULTS

Administration of nov038/CD40 inhibited the development of TNBS colitis as assessed by weight loss, histology and cytokine profiles; unformulated CD40 ASO or nov038 encapsulating an unrelated ASO (nov038/SCR) were ineffective. The novel agent is potent as it completely suppressed even established colitis with a single treatment and significantly reduced T-cell activation as well as levels of pro-inflammatory mediators in serum. The inhibition of CD40 specifically occurred in macrophages, but not in B-cells. In contrast to prednisolone, standard treatment for inflammatory bowel diseases (IBD) that is effective in a single administration and involves extensive immunosuppression, nov038/CD40 did not affect the number of B- or Treg cells. Eventually, we observed a largely intact neoimmunity under conditions of a CD40 inhibition.

CONCLUSIONS

Administration of nov038/CD40, but neither naked CD40 ASO nor nov038/SCR, prevents the development and treats established colitis in mice. Delivery of CD40 ASO in nov038 is highly cell-specific as it selectively suppresses CD40 on macrophages, but not on B-cells; the novel agent has strong anti-inflammatory characteristics without being immunosuppressive.

Inhibition of beta A4 production by specific modulation of beta-secretase activity

To study amyloid precursor protein (APP) processing we expressed different APP isoforms with and without the Swedish mutation and the membrane inserted C-terminal 100 residues of APP (SPA4CT) in the human neuroblastoma cell line SY5Y. We show that expression of the Swedish mutation results in a significant production of the amyloidogenic intermediate A4CT, which is further processed by gamma-secretase leading to an overproduction of beta A4. Treatment with methylamine and ammonium chloride, inhibitors interfering with intracellular transport mechanisms, inhibits beta-secretase activity without influencing the physiological APP cleavage by alpha-secretase activity. By expressing SPA4CT, we demonstrate that secretion, but not generation, of beta A4 from SPA4CT is inhibited by methylamine resulting in intracellular beta A4. This provides experimental evidence for the intracellular localization of gamma-secretase activity and beta A4 generation.