[Proteomic analysis and verification of protein expression after upregulation of human CD99 in Hodgkin lymphoma cell line L428].

Objective: To investigate the proteins expression difference after upregulation of human CD99 in Hodgkin Lymphoma cell line, L428 cell, and verify the function of differential proteins. Methods: The differential proteins were detected by two-dimensional fluorescence difference gel electrophoresis and mass spectrometry analysis, cluster analysis was done by GOfact. Results: There were 38 proteins screened out, of which 21 proteins were positively associated with CD99, while 17 proteins were negative. Among the 38 proteins, 32 proteins participated in biological process, and 35 proteins were involved in the composition and construction. And 28 proteins participated in multifaceted biological activities including antioxidation, protein binding, catalytic activity, regulation of enzyme, signal transduction, molecular structure, regulation of translation and ion transport. Conclusions: The changes of the differential proteins, correlated with cytoskeleton, cell differentiation, signal pathway and regulating gene expression, are closely relevant to the translation between Hodgkin/Reed-Sternberg and B lymphocyte cell.

[Expression of Septin2 in Hodgkin lymphoma cell line L428 and its role in promoting H/RS cells' redifferentiation to B lymphocytes].

Objective: To explore the role of GTP binding protein 2 (Septin2) in the differentiation of Hodgkin's Lymphoma H/RS cells (Hodgkin/Reed-Sternberg) to B lymphocytes. Methods: The expressions of Septin2 mRNA and protein in Hodgkin's Lymphoma cell line L428 which CD99 was overexpressed were detected by RT-qPCR and Western blot,confocal laser microscopy and immunocytochemistry (ICC) . RT-qPCR and Western blot were used to assay the expression of Septin2 after Septin2-siRNA transfected into L428 cells, and confocal laser microscopy, CCK8 assay and flow cytometry were used to analyze the changes of F-actin cytoskeleton,cell proliferation ability and immunophenotype. Results: The low expressions of Septin2 mRNA and protein were detected in L428 cell line after overexpresion of CD99 (0.329±0.019 vs 1.000, P=0.001) and Septin2 siRNA transfection (0.276±0.025 vs 1.000, P=0.000) compared to controls. Compared to vector group, Septin2 siRNA transfection could lead to decrease of cell size, decline of proliferation activity (F=204.927, P<0.001) and reconstruction of F-actin cytoskeleton, and the expression of specific antigen markers CD30 and CD15 of H/RS cell decreased, B cell antigen marker CD19 as well as germinal center marker CD10 and early plasma cell marker CD38 were up-regulated. Conclusion: Septin2 interference promotes H/RS cells' redifferentiation to B lymphocytes.

Avalanche dynamics of granular materials under the slumping regime in a rotating drum as revealed by speckle visibility spectroscopy.

We used speckle visibility spectroscopy to measure the time-resolved dynamcis of avalanching down the inclined surface of a granular material in a half-full rotating drum operating in the slumping regime. The distribution of the avalanche period, t(d), rest time between them, t(r), and peak particle velocity fluctuation, δv(p)(2), are all normally distributed. While the distributions of the two times at the top and bottom of the free surface are very similar, the particle velocity fluctuation is greater at the bottom of the free surface than at the top. The rest time is observed to be inversely related to the drum speed. Combining this with the relation of t(r) and the difference of the upper and lower angle of repose for the granular material, Δθ, we find that the latter decreases linearly with increasing rotational speed. We also observe that t(d) increases in a linear fashion with the drum speed. Using the relation of t(r) and the distance that particles have to move during an avalanche, we further find that a new scaling relation of the mean number of avalanches required to traverse the free surface with drum speed. We find that the slumping frequency increases with the rotating speed before becoming constant in the slumping-to-rolling transition region. Finally, we find that the average peak of the fluctuation speed of the avalanche, δv(p)(2), increases linearly with the drum speed.

Effect of plasmon-enhancement on photophysics in upconverting nanoparticles.

Surface plasmon polaritons (SPP) waves have been shown to significantly affect the near-field photophysical phenomenon. In particular, strong Coulombic interactions can enhance nearby non-linear optics and energy transfer process, while SPP waves also affect other photophysical processes like quenching observed in fluorescent and excitonic systems. Here, using different plasmonic substrates, we show the effect of plasmon-enhancement on quenching, phonon-assisted non-radiative decay, weak Purcell effect or electromagnetic field enhancement, and energy transfer rates of upconverting doped-lanthanide nanoparticles. While the resonant plasmons enhance the local electromagnetic field and the rate of energy transfer leading to enhanced upconversion photoluminescence of infrared radiation to visible light, it can also increase the quenching and non-radiative decay rates of photoexcited electron-hole pairs leading to losses and lower efficiency. These results can guide the design of optimized substrate geometry for using surface plasmons to modulate the photophysics in other applications too.

Electron-phonon and magnetoelastic interactions in ferromagnetic Co[N(CN)2]2.

We combined Raman and infrared vibrational spectroscopies with complementary lattice dynamics calculations and magnetization measurements to reveal the dynamic aspects of charge-lattice-spin coupling in Co[N(CN)2]2. Our work uncovers electron-phonon coupling as a magnetic field-driven avoided crossing of the low-lying Co2+ electronic excitation with two ligand phonons and a magnetoelastic effect that signals a flexible local CoN6 environment. Their simultaneous presence indicates the ease with which energy is transferred over multiple length and time scales in this system.

Quantum critical transition amplifies magnetoelastic coupling in Mn[N(CN)2]2.

We report the discovery of a magnetic quantum critical transition in Mn[N(CN)(2)](2) that drives the system from a canted antiferromagnetic state to the fully polarized state with amplified magnetoelastic coupling as an intrinsic part of the process. The local lattice distortions, revealed through systematic phonon frequency shifts, suggest a combined MnN(6) octahedra distortion+counterrotation mechanism that reduces antiferromagnetic interactions and acts to accommodate the field-induced state. These findings deepen our understanding of magnetoelastic coupling near a magnetic quantum critical point and away from the static limit.

Isolation and characterization of the major form of human MUC18 cDNA gene and correlation of MUC18 over-expression in prostate cancer cell lines and tissues with malignant progression.

Ectopical expression of huMUC18, a cell adhesion molecule in the immunoglobulin gene superfamily, causes a non-metastatic human melanoma cell line to become metastatic in a nude mouse system. To determine if MUC18 expression correlates with the development and malignant progression of prostate cancer, we investigated differential expression of human MUC18 (huMUC18) in normal prostate epithelial cells, prostate cancer cell lines, and prostatic normal and cancer tissues. We cloned and characterized the human MUC18 (huMUC18) cDNA gene from three human prostate cancer cell lines and three human melanoma cell lines. The cDNA sequences from the six human cancer cell lines were identical except differences in one to five nucleotides. The deduced amino acid sequences of the longest ORF were 646 amino acids that were identical in these cDNAs except for one to three amino acid residues. The amino acid sequences of all our huMUC18 cDNA genes are similar to that cloned by other group (GenBank access #M28882) except differences in the same seven amino acids. We conclude that huMUC18 cDNA gene reported here represents the gene product from a major allele. The MUC18 mRNA and protein was expressed in three metastatic prostate cancer cell lines (TSU-PR1, DU145, and PC-3), but not in one non-metastatic prostate cancer cell line (LNCaP.FGC). The expression of huMUC18 in these four cell lines is positively related to their extent of in vitro motility and invasiveness and in vivo metastasis in nude mice. HuMUC18 protein was also expressed at high levels in extracts prepared from tissue sample sections containing high grade prostatic intraepithelial neoplasia (PIN), but weakly expressed in extracts prepared from cultured primary normal prostatic epithelial cells and the normal prostate gland. Immunohistochemical analysis showed that huMUC18 was expressed at higher levels in the epithelial cells of high-grade PIN and prostatic carcinomas, and in cells of a perineural invasion, a lymph node, and a lung metastases compared to that in normal or benign hyperplastic epithelium (BPH). We therefore conclude that MUC18 expression is increased during prostate cancer initiation (high grade PIN) and progression to carcinoma, and in metastatic cell lines and metastatic carcinoma. Increased expression of MUC18 is implicated to play an important role in developing and malignant progression of human prostate cancer. Furthermore, the lacking of predominant cytoplasmic membrane expression of MUC18 appeared to correlate with malignant progression of prostate cancer.

Loss of heterozygosity on the long arm of human chromosome 7 in sporadic renal cell carcinomas.

Cytogenetic and molecular analysis of DNA sequences with highly polymorphic microsatellite markers have implicated allele loss in several chromosomal regions including 3p, 6p, 6q, 8p, 9p, 9q, 11p and 14q in the pathogenesis of sporadic renal cell carcinomas (RCCs). Deletions involving the long arm of chromosome 7 have not been described in RCCs although they have been seen in several other tumor types. However, there have been no detailed analysis of loss of heterozygosity (LOH) of 7q sequences in sporadic RCCs. We therefore studied LOH for DNA sequences on 7q with 10 highly polymorphic markers in 92 matched normal/tumor samples representing sporadic RCCs including papillary, nonpapillary, and oncocytomas in order to determine whether allelic loss could be detected in a tumor type with no visible 7q rearrangements at the cytogenetic level. We found chromosome 7q allele loss in 59 of 92 cases (64%) involving one, two, or more microsatellite markers. The most common allele loss included loci D7S522 (24%) and D7S649 (30%) at 7q31.1-31.2, a region that contains one of the common fragile sites, FRA7G. By comparative multiplex PCR analysis, we detected a homozygous deletion of one marker in the 7q 31.1-31.2 region in one tumor, RC21. These results support the idea that a tumor suppressor gene in 7q31 is involved in the pathogenesis of sporadic renal cell carcinomas.

Frequent breakpoints in the region surrounding FRA3B in sporadic renal cell carcinomas.

The constitutive fragile site at chromosomal band 3p14.2, FRA3B, is the most active common fragile site in the human genome. We have localized aphidicolin-induced breakpoints to two distinct clusters, separated by 200 Kb, in FRA3B (Paradee et al., 1996). Sequence analysis of these regions identified two polymorphic microsatellite markers immediately adjacent to each of these breakpoint clusters. In this report we have used these two new microsatellites and 14 additional 3p microsatellites to analyse chromosome 3p breakage and loss in 94 sporadic RCC samples, including nonpapillary, papillary and oncocytomas. We have found heterozygous loss of 3p14 sequences in >60% of the RCC samples, including both clear cell and papillary renal cell carcinomas. We have found frequent breakage in the region immediately surrounding FRA3B, demonstrating that FRA3B does play a role in chromosome breakage and loss in RCC. In contrast to other reports, >50% of the papillary tumors also showed LOH of 3p markers. We also observed microsatellite instability (MIN) with most of the tested markers in seven of eight oncocytomas and one of 69 clear cell carcinomas. The MIN in some oncocytomas was of the RER+ (replication error) type I phenotype. None of the five 3p14.2 markers detected any homozygous deletions in tumor samples, but 69/94 (73%) of the tumors had LOH for the region, which includes the recently identified FHIT gene.