ASPM overexpression enhances cellular proliferation and migration and predicts worse prognosis for papillary renal cell carcinoma

Various studies have recognized the vital role of the abnormal spindle microtubule assembly (ASPM) gene in the progression of numerous tumors and its association with their poorer clinical outcomes. Nonetheless, the clinical significance and regulatory mechanism of ASPM in papillary renal cell carcinoma (PRCC) have not been illuminated. Herein, we designed a series of experiments to determine the functional significance of ASPM in PRCC. The expression of ASPM was significantly elevated in PRCC tissues and cells, and a higher expression level of ASPM was associated with poor clinical outcomes in patients with PRCC. Following the knockdown of ASPM, the proliferation, invasion, and migration abilities of PRCC cells were all repressed. Moreover, the silencing of ASPM attenuated the expressions of crucial proteins involved in Wnt/b-catenin signaling pathway, including Dvl-2, β-catenin, TCF4, and LEF1. Our study shows the biological significance of ASPM in PRCC and provides new insights for exploring therapeutic targets in PRCC.

The active compounds derived from Psoralea corylifolia for photochemotherapy against psoriasis-like lesions: The relationship between structure and percutaneous absorption

8‑Methoxypsoralen (8-MOP) in combination with ultraviolet A (PUVA) is a photochemotherapy for management of psoriasis. 8-MOP is a natural compound from Psoralea corylifolia. The present work was undertaken to evaluate the percutaneous absorption of five compounds derived from P. corylifolia, and to further explore the inhibitory effect on psoriasis-like lesions generated by imiquimod stimulation in a mouse model. 8-MOP, psoralen, isopsoralen, psoralidin, and bakuchiol were comparatively tested for in vitro skin permeation, keratinocyte apoptosis, and in vivo antipsoriatic potency. The pig ear skin deposition of 8-MOP, isopsoralen, and bakuchiol at an equimolar dose was 0.47, 0.58, and 0.50 nmol/mg, respectively, which was comparable and higher than that of psoralen (0.25 nmol/mg) and psoralidin (0.14 nmol/mg). Psoralidin and bakuchiol were absorbed into the skin without further penetration across the skin. Besides experimental data of physicochemical properties, the hydrogen bond number, total polarity surface, and stratum corneum lipid docking calculated could explain the correlation of the penetrant structure with the skin permeability. The antiproliferative activity against keratinocytes was stronger for 8-MOP and isopsoralen than the others. Topical application of PUVA by using 8-MOP and isopsoralen on imiquimod-induced plaque significantly reduced transepidermal water loss from 55 to 33 and 38 g/m²/h, respectively. The epidermal thickening elicited by imiquimod (117 μm) was decreased to 62 and 26 μm by 8-MOP and isopsoralen application. IL-6 expression in psoriasiform skin was downregulated by isopsoralen but not 8-MOP. Isopsoralen may be a potential candidate for PUVA therapy.

Passive targeting of thermosensitive diblock copolymer micelles to the lungs: synthesis and characterization of poly(N-isopropylacrylamide)-block-poly(ε-caprolactone)

BACKGROUND

Amphiphilic poly(N-isopropylacrylamide)-block-poly(ε-caprolactone) (PNiPAAm-b-PCL) copolymers were synthesized by ring-opening polymerization to form thermosensitive micelles as nanocarriers for bioimaging and carboplatin delivery.

RESULTS

The critical micelle concentration increased from 1.8 to 3.5 mg/l following the decrease of the PNiPAAm chain length. The copolymers revealed a lower critical solution temperature (LCST) between 33 and 40°C. The copolymers self-assembled to form spherical particles of 146-199 nm in diameter. Carboplatin in micelles exhibited a slower release at 37°C relative to that at 25°C due to the gel layer formation on the micellar shell above the LCST. The micelles containing dye or carboplatin were intravenously injected into the rats for in vivo bioimaging and drug biodistribution. The bioimaging profiles showed a significant accumulation of micelles in the lungs. The micelles could minimize the reticuloendothelial system (RES) recognition of the dye. In vivo biodistribution demonstrated an improved pulmonary accumulation of carboplatin from 2.5 to 3.4 μg/mg by the micelles as compared to the control solution. Carboplatin accumulation in the heart and kidneys was reduced after encapsulation by the micelles.

CONCLUSION

This study supports the potential of PNiPAAm-b-PCL micelles to passively target the lungs and attenuate RES uptake and possible side effects.

Disulfate ion as an intermediate to sulfuric Acid in Acid rain formation

The oxidation of the bisulfite ion by dissolved oxygen to produce sulfate ion involves the formation of a previously undetected intermediate. This intermediate has a fairly strong Raman band at 1090 wave numbers and a weak Raman band at 740 wave numbers, both of which are probably due to sulfur-oxygen stretches. The intermediate is proposed to be the disulfate ion S(2)O(7)(2-), which hydrolyzes into H(+) and either SO(4)(2-) or HSO(4)(2-) with a half-life of about 52 seconds at 25 degrees C.

Loading of DNA-binding factors to an erythroid enhancer

The HS-40 enhancer is the major cis-acting regulatory element responsible for the developmental stage- and erythroid lineage-specific expression of the human alpha-like globin genes, the embryonic zeta and the adult alpha2/alpha/1. A model has been proposed in which competitive factor binding at one of the HS-40 motifs, 3'-NA, modulates the capability of HS-40 to activate the embryonic zeta-globin promoter. Furthermore, this modulation was thought to be mediated through configurational changes of the HS-40 enhanceosome during development. In this study, we have further investigated the molecular basis of this model. First, human erythroid K562 cells stably integrated with various HS-40 mutants cis linked to a human alpha-globin promoter-growth hormone hybrid gene were analyzed by genomic footprinting and expression analysis. By the assay, we demonstrate that factors bound at different motifs of HS-40 indeed act in concert to build a fully functional enhanceosome. Thus, modification of factor binding at a single motif could drastically change the configuration and function of the HS-40 enhanceosome. Second, a specific 1-bp, GC-->TA mutation in the 3'-NA motif of HS-40, 3'-NA(II), has been shown previously to cause significant derepression of the embryonic zeta-globin promoter activity in erythroid cells. This derepression was hypothesized to be regulated through competitive binding of different nuclear factors, in particular AP1 and NF-E2, to the 3'-NA motif. By gel mobility shift and transient cotransfection assays, we now show that 3'-NA(II) mutation completely abolishes the binding of small MafK homodimer. Surprisingly, NF-E2 as well as AP1 can still bind to the 3'-NA(II) sequence. The association constants of both NF-E2 and AP1 are similar to their interactions with the wild-type 3'-NA motif. However, the 3'-NA(II) mutation causes an approximately twofold reduction of the binding affinity of NF-E2 factor to the 3'-NA motif. This reduction of affinity could be accounted for by a twofold-higher rate of dissociation of the NF-E2-3'-NA(II) complex. Finally, we show by chromatin immunoprecipitation experiments that only binding of NF-E2, not AP1, could be detected in vivo in K562 cells around the HS-40 region. These data exclude a role for AP1 in the developmental regulation of the human alpha-globin locus via the 3'-NA motif of HS-40 in embryonic/fetal erythroid cells. Furthermore, extrapolation of the in vitro binding studies suggests that factors other than NF-E2, such as the small Maf homodimers, are likely involved in the regulation of the HS-40 function in vivo.

Isolation and characterization of a newly identified type II restriction endonuclease from a local Streptomyces sp. in Taiwan

Streptomyces chusanensis ZS-2, isolated from a soil sample in Chusan in Taiwan, was found to produce a new Type II restriction endonuclease. This restriction enzyme was designated as SchI. The purified enzyme was characterized as having a subunit mol wt of 28 kDa, and was apparently free from exonuclease activities. It cleaves the phosphodiester bond between the fourth C and the fifth G on the 5'-CCGCGG-3' sequence of DNAs, leaving a 2-nucleotide protruding end at its 3' site. This data suggests that SchI is an isoschizomer of SacII. In addition, based on the comparison between SchI and SacII regarding reaction parameters, it seems that SchI is a better choice of restriction enzyme for genetic analysis and mapping.

Transcriptional activation of human adult alpha-globin genes by hypersensitive site-40 enhancer: function of nuclear factor-binding motifs occupied in erythroid cells

The developmental stage- and erythroid lineage-specific activation of the human embryonic zeta- and fetal/adult alpha-globin genes is controlled by an upstream regulatory element [hypersensitive site (HS)-40] with locus control region properties, a process mediated by multiple nuclear factor-DNA complexes. In vitro DNase I protection experiments of the two G+C-rich, adult alpha-globin promoters have revealed a number of binding sites for nuclear factors that are common to HeLa and K-562 extracts. However, genomic footprinting analysis has demonstrated that only a subset of these sites, clustered between -130 and +1, is occupied in an erythroid tissue-specific manner. The function of these in vivo-occupied motifs of the alpha-globin promoters, as well as those previously mapped in the HS-40 region, is assayed by site-directed mutagenesis and transient expression in embryonic/fetal erythroid K-562 cells. These studies, together with our expression data on the human embryonic zeta-globin promoter, provide a comprehensive view of the functional roles of individual nuclear factor-DNA complexes in the final stages of transcriptional activation of the human alpha-like globin promoters by the HS-40 element.