Myeloid-derived suppressor cells (MDSCs) are a heterogeneous family of myeloid cells that suppress T cell immunity in tumor-bearing hosts. In patients with colon cancer, MDSCs have recently been described as Lin−/lowHLA-DR−CD11b+CD33+ cells correlating with cancer stage, metastasis and chemotherapy response. To learn in more detail the dynamic change and clinical relevance of circulating and tumor-infiltrating Lin−/lowHLA-DR−CD11b+CD33+ MDSC in colorectal cancer, we harvested the blood from 64 patients with varying stage of colorectal cancer and tumor and matched paraneoplastic tissues from 5 patients with advanced colorectal cancer, subjected them to multicolor flow cytometric analysis of percentage, absolute number and phenotype of MDSC and finally characterized their immunosuppressive functions. Our results demonstrate that peripheral blood from colorectal cancer patients contains markedly increased percentage and absolute number of Lin−/lowHLA-DR−CD11b+CD33+ MDSCs compared with healthy individuals, and this increase is closely correlated with clinical cancer stage and tumor metastasis but not primary tumor size and serum concentrations of cancer biomarker. A similar increase of MDSCs was also observed in the tumor tissues. Phenotyping MDSCs shows that they express high CD13 and CD39, low CD115, CD117, CD124 and PD-L1, and devoid of CD14, CD15 and CD66b, reminiscent of precursor myeloid cells. MDSCs from cancer patients but not healthy donors have the immunosuppressive activity and were able to inhibit in vitro autologous T-cell proliferation. Collectively, this study substantiates the presence of increased immunosuppressive circulating and tumor-resident Lin−/lowHLA-DR−CD11b+CD33+ MDSCs in patients with colorectal cancers correlating with cancer stage and metastasis, and suggests that pharmacologic blockade of MDSCs should be considered in future clinical trials.

Without any sample pretreatment, trace amounts of melamine in various milk products were rapidly detected noting the characteristic fragments (i.e., m/z 110, 85, and 60) in the MS/MS spectrum of protonated melamine molecules (m/z 127) recorded by using surface desorption atmospheric pressure chemical ionization mass spectrometry. Signal responses of the most abundant ionic fragment (m/z 85) of protonated melamine were well correlated with the amounts of melaime in milk products, showing a dynamic range about 5 orders of magnitude. The limit of detection (LOD) was found to be 3.4 x 10(-15) g/mm(2) (S/N = 3) for the detection of pure melamine deposited on the paper surface, which was much lower than that for detection of melamine in powdered milk (1.6 x 10(-11) g/mm(2), S/N = 3) or liquid milk (1.3 x 10(-12) g/mm(2), S/N = 3). The significant difference in LOD was ascribed to the relatively strong molecular interactions between melamine and the matrix such as proteins in the milk products. As demonstrated using desorption electrospray ionization (DESI) for melamine detection, weakening the molecular interaction between analytes and proteins is proposed as a general strategy to improve the sensitivity of ambient mass spectrometry for direct detection of analytes bound in protein matrixes. The relative standard deviation (RSD) and the recovery of this method were found to be 5.2 approximately 11.9% and 87 approximately 113%, respectively, for the detection of melamine in milk products. A single sample analysis was completed within a few seconds, providing a particularly convenient way to rapidly screen melamine presence in milk products.

A novel linear-hyperbranched multiblock polyethylene was prepared from ethylene monomer alone via chain walking and chain shuttling polymerization in the presence of chain transfer agent (ZnEt 2 ). In the binary catalyst system, R-diimine nickel(II) bromide complex (CatA) produced chain segments with hyperbranched architecture via chain walking, and ansa-ethylenebis(1-η 5 -indenyl)zirconium dichloride (CatB) yielded linear chain segments, while ZnEt 2 facilitated chain exchanges between two active metal centers. The resultant multiblock polyethylene featured a narrow weight distribution and useful combining properties of linear and branched polyethylene. Further, polymers were expediently prepared in an effective and economical polymerization process from ethylene monomer alone.

In this protocol, the sample (which could be a bulk or heterogeneous fluid, or a greasy surface) is treated with a neutral desorption (ND) sampling gas beam, and the resulting analyte mixtures are directly characterized by extractive electrospray ionization mass spectrometry (EESI-MS). The ND device can be specifically constructed such that the sampling gas beam is bubbled through the liquid sample (microjet sampling) or directed to impact the sample surface (e.g., for the analysis of a material like cheese). The ND-EESI-MS analysis process requires no sample pretreatment because it can tolerate an extremely complex matrix. ND-EESI-MS allows real-time, online chemical profiling of highly viscous samples under ambient conditions. Both volatile and nonvolatile analytes from viscous samples can easily be detected and quantified by ND-EESI-MS, thereby providing an MS-based analytical platform for multiple disciplines (e.g., for the food industry, for drug discovery, and for the biological and life sciences). Here we describe the ND-EESI-MS protocol for viscous sample analysis, including the experimental design, equipment setup, reagent preparation, data acquisition and analysis steps. The data collection process takes <1 min per sample, although the time required for the whole procedure, which largely depends on the experimental preparation processes, might be considerably longer.

In metabolomics studies and clinical diagnosis, interest is increasing in the rapid analysis of exhaled breath. In vivo breath analysis offers a unique, unobtrusive, non-invasive method of investigating human metabolism. To analyze breath in vivo, we constructed a novel platform of extractive electrospray ionization (EESI) ion trap mass spectrometry (ITMS) using a home-made EESI source coupled to a linear trap quadrupole mass spectrometer. A reference compound (authentic n-octyl amine) was used to evaluate effects of systematically varying selected characteristics of the EESI source on signal intensity. Under the optimized working conditions, metabolic changes of human bodies were in vivo followed by performing rapid breath analysis using the multi-stage EESI-ITMS tandem mass spectrometry platform. For nicotine, a limit of determination was found to be 0.05 fg mL(-1) (S/N = 3, RSD = 5.0 %, n = 10) for nicotine in aerosol standard samples; the dynamic response range was from 0.0155 pg mL(-1) to 155 pg mL(-1). The concentration of nicotine in the exhaled breath of a regular smoker was in vivo determined to be 5.8 pg mL(-1), without any sample pre-treatment. Our results show that EESI-ITMS is a powerful analytical platform to provide high sensitivity, high specificity and high throughput for semi-quantitative analysis of complex samples in life science, particularly for in vivo metabolomics studies.

Tissue spray ionization mass spectrometry (TSI-MS) directly on small tissue samples has been shown to provide highly specific molecular information. In this study, we apply this method to the analysis of 38 pairs of human lung squamous cell carcinoma tissue (cancer) and adjacent normal lung tissue (normal). The main components of pulmonary surfactants, dipalmitoyl phosphatidylcholine (DPPC, m/z 757.47), phosphatidylcholine (POPC, m/z 782.52), oleoyl phosphatidylcholine (DOPC, m/z 808.49), and arachidonic acid stearoyl phosphatidylcholine (SAPC, m/z 832.43), were identified using high-resolution tandem mass spectrometry. Monte Carlo sampling partial least squares linear discriminant analysis (PLS-LDA) was used to distinguish full-mass-range mass spectra of cancer samples from the mass spectra of normal tissues. With 5 principal components and 30 – 40 Monte Carlo samplings, the accuracy of cancer identification in matched tissue samples reached 94.42%. Classification of a tissue sample required less than 1 min, which is much faster than the analysis of frozen sections. The rapid, in situ diagnosis with minimal sample consumption provided by TSI-MS is advantageous for surgeons. TSI-MS allows them to make more informed decisions during surgery.

Protonated water molecules generated by an ambient corona discharge were directed to impact tea leaves for desorption/ionization at atmospheric pressure. Thus, a novel method based on surface desorption chemical ionization mass spectrometry (DAPCI-MS) has been developed for rapid analysis of tea products without any sample pretreatment. Under the optimized experimental conditions, DAPCI MS spectra of various tea samples are recorded rapidly, and the resulting mass spectra are chemical fingerprints that characterize the tea samples. On the basis of the mass spectral fingerprints, 40 tea samples including green tea, oolong tea, and jasmine tea were successfully differentiated by principal component analysis (PCA) of the mass spectral raw data. The PCA results were also validated with cluster analysis and supervised PCA analysis. The alteration of signal intensity caused by rough surfaces of tea leaves did not cause failure in the separation of the tea products. The experimental findings show that DAPCI-MS creates ions of both volatile and nonvolatile compounds in tea products at atmospheric pressure, providing a practical and convenient tool for high-throughput differentiation of tea products.

Hematopoietic pre-B cell leukemia transcription factor (PBX)-interacting protein (HPIP) was shown to play a role in cancer development and progression. However, the role of HPIP in colorectal cancer (CRC) is unknown. Here, we report that HPIP is overexpressed in most of CRC patients and predicts poor clinical outcome in CRC. HPIP promotes CRC cell proliferation via activation of G1/S and G2/M checkpoint transitions, concomitant with a marked increase of the positive cell cycle regulators, including cyclin D1, cyclin A, and cyclin B1. HPIP inhibits CRC cell apoptosis accompanied by the decreased levels of BAX and PIG3, the inducers of apoptosis, and the increased level of the apoptosis inhibitor BCL2. HPIP blocks caspase-3-mediated cleavage of PARP, an important apoptosis marker. HPIP promotes CRC cell migration and invasion, and regulates epithelial-mesenchymal transition (EMT), which plays a critical role in cancer cell migration and invasion. Activation of MAPK/ERK1/2 and PI3k/AKT pathways is required for HPIP modulation of CRC cell proliferation, migration and EMT. Moreover, HPIP knockdown suppresses colorectal tumor growth in nude mice. These data highlight the important role of HPIP in CRC cell proliferation and progression and suggest that HPIP may be a useful target for CRC therapy.