[Curcumin inhibited rat colorectal carcinogenesis by activating PPAR-γ: an experimental study].

OBJECTIVE: To explore the chemopreventive effect of curcumin on DMH induced colorectal carcinogenesis and the underlining mechanism. METHODS: Totally 40 Wistar rats were divided into the model group and the curcumin group by random digit table, 20 in each group. Meanwhile, a normal control group was set up (n =10). A colorectal cancer model was induced by subcutaneously injecting 20 mg/kg DMH. The tumor incidence and the inhibition rate were calculated. The effect of curcumin on the expression of peroxisome proliferator-activated receptor gamma (PPARγ) in rat colon mucosal tissues was observed using immunohistochemistry and Western blot. HT 29 cell line were cultured and divided into a control group, the curcumin + GW9662 (2-chloro-5-nitro-N-4-phenylbenzamide) intervention group, and the curcumin group. The inhibition of different concentrations curcumin on HT29 cell line was detected using MTT. The expression of curcumin on PPARy was also detected using Western blot. RESULTS: The tumor incidence was 80. 00% (12/15 cases) in the model group, obviously higher than that of the curcumin group (58. 82%, 10/17 cases, P <0. 05). The inhibition rate of curcumin on DMH induced colorected carcinoma reached 26. 46%. Compared with the normal control group, the expression of PPARγ protein was significantly increased in the curcumin group and the model group (P <0. 01). Compared with the model group at the same time point, the expression of PPARy protein was significantly enhanced in the curcumin group (P <0. 05). MTT analysis showed that curcumin could inhibit the proliferation of in vitro HT 29 cells in dose and time dependent manners. The expression of PPARy protein was significantly increased in the GW9662 group and the curcumin group, showing statistical difference when compared with the normal control group (P <0. 01). Compared with the GW9662 group, the expression of PPARγ protein was significantly increased in the curcumin group (P <0. 01). CONCLUSION: Curcumin could inhibit DMH-induced rat colorectal carcinogenesis and the growth of in vitro cultured HT 29 cell line, which might be achieved by activating PPARy signal transduction pathway.

Recurrent gain-of-function USP8 mutations in Cushing's disease.

Cushing's disease, also known as adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas (PAs) that cause excess cortisol production, accounts for up to 85% of corticotrophin-dependent Cushing's syndrome cases. However, the genetic alterations in this disease are unclear. Here, we performed whole-exome sequencing of DNA derived from 12 ACTH-secreting PAs and matched blood samples, which revealed three types of somatic mutations in a candidate gene, USP8 (encoding ubiquitin-specific protease 8), exclusively in exon 14 in 8 of 12 ACTH-secreting PAs. We further evaluated somatic USP8 mutations in additional 258 PAs by Sanger sequencing. Targeted sequencing further identified a total of 17 types of USP8 variants in 67 of 108 ACTH-secreting PAs (62.04%). However, none of these mutations was detected in other types of PAs (n = 150). These mutations aggregate within the 14-3-3 binding motif of USP8 and disrupt the interaction between USP8 and 14-3-3 protein, resulting in an elevated capacity to protect EGFR from lysosomal degradation. Accordingly, PAs with mutated USP8 display a higher incidence of EGFR expression, elevated EGFR protein abundance and mRNA expression levels of POMC, which encodes the precursor of ACTH. PAs with mutated USP8 are significantly smaller in size and have higher ACTH production than wild-type PAs. In surgically resected primary USP8-mutated tumor cells, USP8 knockdown or blocking EGFR effectively attenuates ACTH secretion. Taken together, somatic gain-of-function USP8 mutations are common and contribute to ACTH overproduction in Cushing's disease. Inhibition of USP8 or EGFR is promising for treating USP8-mutated corticotrophin adenoma. Our study highlights the potentially functional mutated gene in Cushing's disease and provides insights into the therapeutics of this disease.

[Establishment of mouse lens epithelial cell lines with the genotype of Hsf4-/-].

OBJECTIVE: To establish mouse lens epithelial cell lines with the genotype of Hsf4-/-. METHODS: The expended mouse lens epithelial cells, which were generated from P6 Hsf4-deficient mouse lens epithelia, were immortalized with SV40-T-antigen and named MLEC/Hsf4-/- cell. The expression of alpha A-crystallin was immunoblotted. Hsf4b cDNA was reconstituted by transiently transfection. RESULTS: The SV40-immortalized cells were in adherent growth mode with spindle morphology, pseudopodia, clear nuclear boundary membrane and cytoplasm translucent. Immunoblotting results indicated that the lens biomarker protein alpha A-crystallin was expressed in MLEC/Hsf4-/- cells. Reconstitution of Hsf4b into MLEC/Hsf4-/- cells upregulated the expression of Hsp25. CONCLUSIONS: The SV40-immortalized MLEC/Hsf4-/- cells have the lens epithelial characteristics and could be used as a tool for studying the signal transduction in vitro.

[Study on vitrification of fly ashes from municipal wastes incinerator with a plasma torch].

TCLP analysis (USEPA method 1311) was employed on fly ash in order to analyze the metals leachability and the concentration of cadmium was 0.3225 mg/L which exceeded state TCLP standard(0.3 mg/L). According to USEPA method 1613, I-TEQ of PCDD/Fs in fly ash was 0.45 ng/g. Then a double arcs DC plasma torch was developed to vitrified fly ash. And the results showed that heavy metals were mostly immobilized in the vitrified slag and also I-TEQ of PCDD/Fs in fly ash was destroyed near 91.6%. The morphology of vitrified slag was amorphous state which showed the glassy slag of SiO2 and the microstructure of slag was very compact.

[Temperature measurement of DC argon plasma jet].

The electron temperature of DC arc plasma jet is an important parameter, which determines the characteristics of plasma jet. The measurement of emission spectrum was performed to obtain the spectral intensities of some Ar lines and the method of diagrammatic view of Boltzmann was adopted to calculate the electron temperature. The results indicated that the electron temperature dropped at different speed along with the axes of the plasma jet and rose rapidly when the current was increased, and it also rose when the flowrate of argon was increased.

[Spectroscopic diagnostics of DC argon plasma at atmospheric pressure].

The optical emission spectra of DC argon plasma at atmospheric pressure were measured inside and outside the arc chamber. The electron temperature was determined from the Boltzmann plot, and the electron density was derived from Stark broadening of Ar I lines. The criteria for the existence of local thermodynamic equilibrium (LTE)in the plasma was discussed. The results indicate that the DC argon plasma at atmospheric pressure under our experimental conditions is in LTE.

[Measurement of rotational and vibrational temperatures in arc plasma based on the first negative system of N2+ (B(2) sigma --> X(2) sigma)].

The molecular emission spectra lines of the first negative system N2+ (B(2) sigma--> X(2) sigma ) are frequently observed in the plasma source containing nitrogen. (0-0) and (1--1) N2+ first negative system molecular bands around 391. 4 nm can be used to the measure the rotational and vibrational temperatures in a DC argon-nitrogen plasma at atmospheric pressure. The proposed method based on the comparison between this experimental emission spectrum and the computer simulated one is presented. The effect of the apparatus function, vibrational temperature and rotational temperatures on the line structure of numerical simulated spectrum is discussed. The results show that the electron temperature, rotational temperature, vibrational temperature and kinetic temperature of plasma arc are almost the same, which can be interpreted as that DC argon-nitrogen arc plasma at atmospheric pressure is in LTE under their experimental conditions.