Non-canonical transcriptional regulation of the poor prognostic factor UGT2B17 in chronic lymphocytic leukemic and normal B cells.

BACKGROUND: High expression of the glycosyltransferase UGT2B17 represents an independent adverse prognostic marker in chronic lymphocytic leukemia (CLL). It also constitutes a predictive marker for therapeutic response and a drug resistance mechanism. The key determinants driving expression of the UGT2B17 gene in normal and leukemic B-cells remain undefined. The UGT2B17 transcriptome is complex and is comprised of at least 10 alternative transcripts, identified by previous RNA-sequencing of liver and intestine. We hypothesized that the transcriptional program regulating UGT2B17 in B-lymphocytes is distinct from the canonical expression previously characterized in the liver. RESULTS: RNA-sequencing and genomics data revealed a specific genomic landscape at the UGT2B17 locus in normal and leukemic B-cells. RNA-sequencing and quantitative PCR data indicated that the UGT2B17 enzyme is solely encoded by alternative transcripts expressed in CLL patient cells and not by the canonical transcript widely expressed in the liver and intestine. Chromatin accessible regions (ATAC-Seq) in CLL cells mapped with alternative promoters and non-coding exons, which may be derived from endogenous retrotransposon elements. By luciferase reporter assays, we identified key cis-regulatory STAT3, RELA and interferon regulatory factor (IRF) binding sequences driving the expression of UGT2B17 in lymphoblastoid and leukemic B-cells. Electrophoretic mobility shift assays and pharmacological inhibition demonstrated key roles for the CLL prosurvival transcription factors STAT3 and NF-κB in the leukemic expression of UGT2B17. CONCLUSIONS: UGT2B17 expression in B-CLL is driven by key regulators of CLL progression. Our data suggest that a NF-κB/STAT3/IRF/UGT2B17 axis may represent a novel B-cell pathway promoting disease progression and drug resistance.

The revolution of PDMS microfluidics in cellular biology.

Microfluidics is revolutionizing the way research on cellular biology has been traditionally conducted. The ability to control the cell physicochemical environment by adjusting flow conditions, while performing cellular analysis at single-cell resolution and high-throughput, has made microfluidics the ideal choice to replace traditional in vitro models. However, such a revolution only truly started with the advent of polydimethylsiloxane (PDMS) as a microfluidic structural material and soft-lithography as a rapid manufacturing technology. Indeed, before the "PDMS age," microfluidic technologies were: costly, time-consuming and, more importantly, accessible only to specialized laboratories and users. The simplicity of molding PDMS in various shapes along with its inherent properties (transparency, biocompatibility, and gas permeability) has spread the applications of innovative microfluidic devices to diverse and important biological fields and clinical studies. This review highlights how PDMS-based microfluidic systems are innovating pre-clinical biological research on cells and organs. These devices were able to cultivate different cell lines, enhance the sensitivity and diagnostic effectiveness of numerous cell-based assays by maintaining consistent chemical gradients, utilizing and detecting the smallest number of analytes while being high-throughput. This review will also assist in identifying the pitfalls in current PDMS-based microfluidic systems to facilitate breakthroughs and advancements in healthcare research.