Biology subjects

Shao, R.

Publications and source records attributed to Shao, R..

5 recordsLinked to original sources

bioRxiv2021

3-Phosphoinositide-dependent kinase 1 drives acquired resistance to osimertinib

Osimertinib sensitive and resistant NSCLC NCI-H1975 clones were used to model osimertinib acquired resistance in humanized mice and delineate potential resistance mechanisms. No new EGFR mutations or loss of the EGFR T790M mutation were found in resistant clones. Resistant tumors in humanized mice were initially partially responsive to osimertinib, then aggressive tumor regrowth occurred accompanied by an immunosuppressive tumor microenvironment. 3-phosphoinositide-dependent kinase 1 (PDK1) was identified as a potential driver of osimertinib acquired resistance, and its selective inhibition by BX795 and CRISPR gene knock out, sensitized resistant clones and a patient derived xenograft (PDX) with acquired resistance to osimertinib. PDK1 knock-out dysregulated PI3K/Akt/mTOR signaling, promoted cell cycle arrest at the G1 phase, and inhibited nuclear translocation of yes-associated protein (YAP). Higher expression of PDK1 was found in patients with progressive disease following osimertinib treatment. PDK1 is a central upstream regulator of two critical drug resistance pathways: PI3K/AKT/mTOR and YAP.

cancer biology↗

bioRxiv2021

Verbena officinalis L. regulates killing efficiency of natural killer cells

Natural killer (NK) cells play a key role in eliminating pathogen-infected cells. Verbena officinalis (V. officinalis) has been used as a medical plant in traditional and modern medicine, exhibiting anti-tumor and anti-inflammation activities, but its roles in immune responses still remains largely elusive. In this work, investigated the regulation of inflammation and NK functions by V. officinalis extract (VO-extract). In an influenza virus infection mouse model, oral administration of VO-extract alleviated lung injury, promoted maturation and activation of NK cells residing in the lung, and decreased the levels of inflammatory cytokines (IL-6, TNF- and IL-1{beta}) in the serum. We further analyzed the impact of five bioactive components of VO-extract on NK killing functions. Among them, Verbenalin enhanced NK killing efficiency significantly as determined by real-time killing assays based on plate-reader or high-throughput live-cell imaging in 3D using primary human NK cells. Further investigation showed that treatment of Verbenalin accelerated killing processes by reducing the contact time of NK cells with their target cells without affecting NK proliferation, expression of cytotoxic proteins, or lytic granule degranulation. Together, our findings reveal that low doses of V. officinalis can achieve a satisfactory anti-inflammation effect against viral infection in vivo, and V. officinalis regulates activation, maturation and killing functions of NK cells. NK killing efficiency is enhanced by Verbenalin from V. officinalis, suggesting a promising potential of verbenalin to fight viral infection.

immunology↗

bioRxiv2021

Newly synthesized RNA Sequencing Characterizes Transcription Dynamics in Three Pluripotent States

Unique transcriptomes define naive, primed and paused pluripotent states in mouse embryonic stem cells. Here we perform transient transcriptome sequencing (TT-seq) to de novo define and quantify coding and non-coding transcription units (TUs) in different pluripotent states. We observe a global reduction of RNA synthesis, total RNA amount and turnover rates in ground state naive cells (2i) and paused pluripotency (mTORi). We demonstrate that elongation velocity can be reliably estimated from TT-seq nascent RNA and RNA polymerase II occupancy and observe a transcriptome-wide attenuation of elongation velocity in the two inhibitor-induced states. We also discover a relationship between elongation velocity and termination read-through distance. Our analysis suggests that steady-state transcriptomes in mouse ES cells are controlled predominantly on the level of RNA synthesis, and that signaling pathways governing different pluripotent states immediately control key parameters of transcription.

systems biology↗

bioRxiv2021

Genome-wide mapping of G-quadruplex structures with CUT&Tag

Single-stranded genomic DNA can fold into G-quadruplex (G4) structures or form DNA:RNA hybrids (R loops). Recent evidence suggests that such non-canonical DNA structures affect gene expression, DNA methylation, replication fork progression and genome stability. When and how G4 structures form and are resolved remains unclear. Here we report the use of Cleavage Under Targets and Tagmentation (CUT&Tag) for mapping native G4 in mammalian cell lines at high resolution and low background. Mild native conditions used for the procedure retain more G4 structures and provide a higher signal-to-noise ratio than ChIP-based methods. We determine the G4 landscape of mouse embryonic stem cells (mESC), observing widespread G4 formation at active promoters, active and poised enhancers. We discover that the presence of G4 motifs and G4 structures distinguishes active and primed enhancers in mESCs. Further, performing R-loop CUT&Tag, we demonstrate the genome-wide co-occurence of single-stranded DNA, G4s and R loops, suggesting an intricate relationship between transcription and non-canonical DNA structures.

genomics↗

bioRxiv2018

Genome Scale Epigenetic Profiling Reveals Five Distinct Subtypes of Colorectal Cancer

BACKGROUNDColorectal cancer is an epigenetically heterogeneous disease, however the extent and spectrum of the CpG Island Methylator Phenotype (CIMP) is not clear.\n\nRESULTSAn unselected cohort of 216 colorectal cancers clustered into five clinically and molecularly distinct subgroups using Illumina 450K DNA methylation arrays. CIMP-High cancers were most frequent in the proximal colons of female patients. These dichotomised into CIMP-Hl and CIMP-H2 based on methylation profile which was supported by over representation of BRAF (74%, P<0.0001) or KRAS (55%, P<0.0001) mutation, respectively. Congruent with increasing methylation, there was a stepwise increase in patient age from 62 years in the CI MP-Negative subgroup to 75 years in the CIMP-Hl subgroup (P<0.0001). There was a striking association between PRC2-marked loci and those subjected to significant gene body methylation in CIMP-type cancers (P<1.6xl078). We identified oncogenes susceptible to gene body methylation and Wnt pathway antagonists resistant to gene body methylation. CIMP cluster specific mutations were observed for genes involved in chromatin remodelling, such as in the SWI/SNF and NuRD complexes, suggesting synthetic lethality.\n\nCONCLUSIONThere are five clinically and molecularly distinct subgroups of colorectal cancer based on genome wide epigenetic profiling. These analyses highlighted an unidentified role for gene body methylation in progression of serrated neoplasia. Subgroup-specific mutation of distinct epigenetic regulator genes revealed potentially druggable vulnerabilities for these cancers, which may provide novel precision medicine approaches.

genomics↗