Targeting NSD2-mediated SRC-3 liquid-liquid phase separation sensitizes bortezomib treatment in multiple myeloma.

Development of chemoresistance is the main reason for failure of clinical management of multiple myeloma (MM), but the genetic and epigenetic aberrations that interact to confer such chemoresistance remains unknown. In the present study, we find that high steroid receptor coactivator-3 (SRC-3) expression is correlated with relapse/refractory and poor outcomes in MM patients treated with bortezomib (BTZ)-based regimens. Furthermore, in immortalized cell lines, high SRC-3 enhances resistance to proteasome inhibitor (PI)-induced apoptosis. Overexpressed histone methyltransferase NSD2 in patients bearing a t(4;14) translocation or in BTZ-resistant MM cells coordinates elevated SRC-3 by enhancing its liquid-liquid phase separation to supranormally modify histone H3 lysine 36 dimethylation (H3K36me2) modifications on promoters of anti-apoptotic genes. Targeting SRC-3 or interference of its interactions with NSD2 using a newly developed inhibitor, SI-2, sensitizes BTZ treatment and overcomes drug resistance both in vitro and in vivo. Taken together, our findings elucidate a previously unrecognized orchestration of SRC-3 and NSD2 in acquired drug resistance of MM and suggest that SI-2 may be efficacious for overcoming drug resistance in MM patients.

Two dimensional separations of human urinary protein digest using a droplet-interfaced platform.

For highly complex mixtures, coelution is a common phenomenon in chromatography. A great deal of resolution is hidden in coelution, and lost due to inevitable molecular diffusion during sample transfer. The molecular diffusion may lead to band broadening and remix of separated peaks, which cause degradation of achievable resolution. In this study, we introduced droplet microfluidics as a high performance sample transfer tool in two dimensional nanoflow liquid chromatography-capillary electrophoresis separation of a human urine sample. The fine fractionation capability and sampling completeness enabled by the droplet-interface demonstrated the 2D system's usefulness in high-resolution mapping of real world biological samples.

[Determination of three organophosphate ester flame retardants in baby carriages by gas chromatography-mass spectrometry combined with solid phase extraction].

Organophosphate esters (OPEs) are high-production-volume chemicals used as flame retardants. Some western countries (e. g. America and European Union) have imposed restrictions on OPEs in baby products due to their similar persistent-organic-pollutants (POPs) properties. So far, there is no domestic or foreign standard for OPEs flame retardants in baby carriages. Ultrasonic extraction was used to extract three OPEs from baby carriages, and the extracts were purified by a florisil solid phase extraction (SPE) column, and finally detected by gas chromatography-mass spectrometry (GC-MS). The spiked recoveries of the three OPEs were in the range of 89.5% to 107.3%. The limits of detection (3S/N) were 0.01 mg/kg, and the limits of quantification (10S/N) were 0.1 mg/kg. This method could eliminate matrix effects and give accurate qualitative analytical results for the three OPE flame retardants in baby carriages. Thirty-seven samples were analyzed and the tris (2-chloro-1-methylethyl) phosphate (TCPP) detection rate was up to 81.1% with the mass concentration range of 1.0-15 312.8 mg/kg, and 32.4% of the samples exceeded the European Union directive (2014/79/EU) for TCPP (> 5 mg/kg), as well as tris (2-chloroethyl) phosphate (TCEP) and tris [2-chloro-1-(chloromethyl) ethyl] phosphate(TDCP) in two samples, which were in the range of 6.2-44.1 mg/kg. Thus, relatively high OPEs flame retardants risk was presented in baby carriages.

Towards high peak capacity separations in normal pressure nanoflow liquid chromatography using meter long packed capillary columns.

Single shot proteomics is a promising approach to high throughput proteomics analysis. In this strategy, long capillary columns are needed to perform long and shallow gradients to achieve high peak capacity and good peak width for informative mass spectrometric detection. Herein, we report that meter long capillary columns, packed with 5 µm particulate material, can be facilely fabricated based on single particle fritting technology. The long columns could reliably generate high peak capacities of 800 in 10 h long gradients for protein digest separations. The operation was within the pressure range (40 MPa) of the most widely used normal pressure nanoLC systems. Due to the excellent life time (>100 injections) and inter-column performance consistency, the meter long capillary columns reported here should be of practical usefulness in single shot proteomics without the need for ultra-high pressure instrumentation.

[Development of a droplet-interfaced high performance liquid chromatography-capillary electrophoresis two dimensional separation platform].

Proteomics demands high resolution multidimensional separation techniques due to its extremely high complexity. Droplet microfluidics provides a series of unique advantages in manipulating micro and nanolitre samples, such as micro-volume operation, limited diffusion and none cross-contaminating, therefore has the potential to be an ideal interface strategy for multidimensional separation. Using the microchips of different structures, functions such as "droplet generation" and "oil depletion" can be realized. Based on these functions, samples can be transferred from continuous flow to segmented flow and then back to continuous flow. In this way, different separation modes can be combined. In this study, droplet technology was utilized as a novel interface strategy in combining high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). Using tryptic peptides mixture as a sample, this two dimensional HPLC-CE system provided high resolution separation with a peak capacity over 3000. This proof-of-principle study has demonstrated the usefulness of droplet interface technology in multidimensional separation.