Biological function and molecular mechanism of Twist2.

Twist2, one of the basic helix-loop-helix protein (bHLH) family members, is responsible for the transcriptional regulation in mesenchymal cell lineages during its development. Twist2 functions as a molecular switch to activate or repress target genes by direct or indirect mechanisms. Twist2 can directly bind with conserved E-box on DNA sequence, to recruit co-activators or repressors, and interfere with the activation or inhibition function through protein-protein interactions with E-protein modulators. Nonsense mutations of Twist2 cause Setleis syndrome. Early research on Twist2 focused on osteogenesis, and then expression differences were found in a wide variety of tumors. Further studies showed that Twist2 plays an important role in cancer epithelial-mesenchymal transition (EMT). Regulation function of Twist2 is controlled by temporal and spatial expression, phosphorylation, dimerization and cell positioning adjustment. The involvement of Twist2 in a broad spectrum of regulatory pathways highlights the importance of understanding its role in normal development, homeostasis and disease. In this review, we summarize the role of Twist2 in osteogenesis differentiation, tumor formation and EMT, and its molecular mechanism. It is helpful to have a thorough understanding of the biological functions of Twist2, and facilitate the transformation and application in diagnosis, development and therapy.

Rhodojaponin VI indirectly targets Cav2.2 channels via N-ethylmaleimide-sensitive fusion protein to alleviate neuropathic pain.

Neuropathic pain is a chronic disease that severely afflicts the life and emotional status of patients, but currently available treatments are often ineffective. Novel therapeutic targets for the alleviation of neuropathic pain are urgently needed. Rhodojaponin VI, a grayanotoxin from Rhododendron molle, showed remarkable antinociceptive efficacy in models of neuropathic pain, but its biotargets and mechanisms are unknown. Given the reversible action of rhodojaponin VI and the narrow range over which its structure can be modified, we perforwmed thermal proteome profiling of the rat dorsal root ganglion to determine the protein target of rhodojaponin VI. N-Ethylmaleimide-sensitive fusion (NSF) was confirmed as the key target of rhodojaponin VI through biological and biophysical experiments. Functional validation showed for the first time that NSF facilitated trafficking of the Cav2.2 channel to induce an increase in Ca2+ current intensity, whereas rhodojaponin VI reversed the effects of NSF. In conclusion, rhodojaponin VI represents a unique class of analgesic natural products targeting Cav2.2 channels via NSF.

Structure-activity relationship of halophenols as a new class of protein tyrosine kinase inhibitors.

A series of new benzophenone and diphenylmethane halophenol derivatives were prepared. Their structures were established based on (1)H NMR, (13)C NMR and HRMS data. All prepared compounds were screened for their in vitro protein tyrosine kinase (PTK) inhibitory activities. The effects of modification of the linker, functional groups and substituted positions at the phenyl ring on PTK inhibitory activity were investigated. Twelve halophenols showed significant PTK inhibitory activity. Among them, compounds 6c, 6d, 7d, 9d, 10d, 11d and 13d exhibited stronger activities than that of genistein, the positive reference compound. The results gave a relatively full and definite description of the structure-activity relationship and provided a foundation for further design and structure optimization of the halophenols.

Synthesis and in vitro protein tyrosine kinase inhibitory activity of furan-2-yl(phenyl)methanone derivatives.

A series of novel furan-2-yl(phenyl)methanone derivatives were synthesized, and their structures were established on the basis of ¹H-NMR, ¹³C-NMR and mass spectral data. All the prepared compounds were screened for their in vitro protein tyrosine kinase inhibitory activity and several new derivatives exhibited promising activity, which, in some cases, was identical to, or even better than that of genistein, a positive reference compound. The preliminary structure-activity relationships of these compounds were investigated and are discussed.

Affinity-based protein profiling to reveal targets of puerarin involved in its protective effect on cardiomyocytes.

Natural products are an important source of new drugs. Some of them may be used directly in clinical settings without further structural modification. One of these directly used natural products is puerarin (Pue), which protects cardiomyocytes against oxidative stress and high glucose stress. Although Pue has been used in clinics for many years, its direct binding targets involved in the protection of cardiomyocytes are not yet fully understood. Here, we reported that Pue could prevent cardiomyocytes from apoptosis under H2O2 and high glucose conditions. Based on affinity-based protein profiling methods, we synthesized an active Pue probe (Pue-DA) with a photosensitive crosslinker to initiate a biological orthogonal reaction. Because of the steric hindrance of Pue-DA, two conformational isomers (syn and anti) unequivocally existed in the probe, and these transformed into one isomer when the probe was heated at 60 °C. We confirmed that the alkylation was on the 7-position phenol group of Pue. Mass spectroscopy revealed that Pue-DA can bind with three proteins, namely CHAF1B, UBE2C, and UBE2T. Finally, cellular thermal shift assay showed that Pue has the ability to stabilize CHAF1B stabilization. The knock-down of CHAF1B reduced the protective effect of Pue on cardiomyocytes. In conclusion, Pue protects cardiomyocytes from apoptosis through binding with CHAF1B.

Activity-based protein profiling reveals that secondary-carbon-centered radicals of synthetic 1,2,4-trioxolanes are predominately responsible for modification of protein targets in malaria parasites.

Endoperoxide-containing antimalarials, such as artemisinin and the synthetic trioxolane OZ439, are prodrugs activated by heme to generate primary and secondary carbon-centered radicals. We employed activity-based protein profiling (ABPP) to show that the secondary-carbon-centered radical of 1,2,4-trioxolanes is primarily responsible for protein labeling in malaria parasites.

Association of 8 loci on chromosome 8q24 with prostate carcinoma risk in northern Chinese men.

Multiple genetic studies have confirmed association of 8q24 variants with susceptibility to prostate cancer (PCa). As PCa risk SNPs may also influence disease outcome, we studied here eight 8q24 risk alleles, and evaluated their role in PCa clinical covariates in northern Chinese men. Blood samples and clinical information were collected from ethnically Chinese men from Northern China with histologically-confirmed PCa (n=289) and from age-matched normal controls (n=288). Eight 8q24 SNPs were genotyped by polymerase chain reaction- high-resolution melting analysis in 577 subjects. We examined the prevalence distribution of 8q24 risk alleles and analyzed the associations between the risk allele and PCa and clinical covariates to infer their impact on aggressive PCa. Three of the eight SNPs were associated with PCa risk in northern Chinese men, including rs16901966 (OR 1.31, 95% CI 1.01-1.70, p=0.042), rs1447295 (OR 1.47, 95% CI 1.09-1.98, p=0.011) and rs10090154 (OR 1.55, 95% CI 1.14-2.12, p=0.005). Haplotype analysis based association with the risk alleles revealed significant differences between cases and controls (OR 1.43, 95%CI 0.99-2.06, p=0.049). The risk alleles rs16901966, rs1447295 and rs10090154 were associated with age at diagnosis and tumor stage as compared with controls, while rs16901966 was associated with aggressive PCa (OR 1.43, 95% CI 1.01-2.03, p=0.042). The evidence for 8q24 SNPs with PCa risk in northern Chinese men showed rs16901966, rs1447295 and rs10090154 at 8q24 (region 1, region 2) to be strongly associated with PCa and clinical covariates. The three SNPs at 8q24 could be PCa susceptible genetic markers in northern Chinese men.

8q24 rs4242382 polymorphism is a risk factor for prostate cancer among multi-ethnic populations: evidence from clinical detection in China and a meta-analysis.

BACKGROUND: Evidence supporting an association between the 8q24 rs4242382-A polymorphism and prostate cancer (PCa) risk has been reported in North American and Europe populations, though data from Asian populations remain limited. We therefore investigated this association by clinical detection in China, and meta-analysis in Asian, Caucasian and African-American populations. MATERIALS AND METHODS: Blood samples and clinical information were collected from ethnically Chinese men from Northern China with histologically- confirmed PCa (n=335) and from age-matched normal controls (n=347). The 8q24 (rs4242382) gene polymorphism was genotyped by polymerase chain reaction-high-resolution melting analysis. We initially analyzed the associations between the risk allele and PCa and clinical covariates. A meta-analysis was then performed using genotyping data from a total of 1,793 PCa cases and 1,864 controls from our study and previously published studies in American and European populations, to determine the association between PCa and risk genotype. RESULTS: The incidence of the risk allele was higher in PCa cases than controls (0.222 vs 0.140, P=7.3?10-5), suggesting that the 8q24 rs4242382-A polymorphism was associated with PCa risk in Chinese men. The genotypes in subjects were in accordance with a dominant genetic model (ORadj=2.03, 95%CI: 1.42-2.91, Padj=1.1?10-4). Presence of the risk allele rs4242382-A at 8q24 was also associated with clinical covariates including age at diagnosis ≥65 years, prostate specific antigen >10 ng/ml, Gleason score <8, tumor stage and aggressive PCa, compared with the non-risk genotype (P=4.6?10-5-3.0?10-2). Meta-analysis confirmed the association between 8q24 rs4242382-A polymorphism and PCa risk (OR=1.62, 95%CI: 1.39-1.88, P=1.0?10-5) across Asian, Caucasian and African American populations. CONCLUSIONS: The replicated data suggest that the 8q24 rs4242382-A variation might be associated with increased PCa susceptibility in Asian, Caucasian and African American populations. These results imply that this polymorphism may be a useful risk biomarker for PCa in multi-ethnic populations.

Susceptibility loci associations with prostate cancer risk in northern Chinese men.

BACKGROUND: KLK3 gene products, like human prostate-specific antigen (PSA), are important biomarkers in the clinical diagnosis of prostate cancer (PCa). G protein-coupled receptor RFX6, C2orf43 and FOXP4 signaling plays important roles in the development of PCa. However, associations of these genes with PCa in northern Chinese men remain to be detailed. This study aimed to investigate their impact on occurrence and level of malignancy. METHODS: All subjects were from Beijing and Tianjin, including 266 cases with prostate cancer and 288 normal individuals as controls. We evaluated associations between clinical covariates (age at diagnosis, prostate specific antigen, Gleason score, tumor stage and aggressive) and 6 candidate PCa risk loci, genotyped by PCR- high resolution melting curve and sequencing methods. RESULTS: Case-control analysis of allelic frequency of PCa associated with PCa showed that one of the 6 candidate risk loci, rs339331 in the RFX6 gene, was associated with reduced risk of prostate cancer (odds ratio (OR) = 0.73, 95% confidence interval (CI) =0.57-0.94, P = 0.013) in northern Chinese men. In addition, subjects with CX (CC+TC) genotypes had a decreased risk for prostrate cancer compared to those carrying the TT homozygote (OR =0.64, 95% CI = 0.45- 0.90, P = 0.008). The TT genotype of 13q22 (rs9600079, T) was associated with tumor stage (P=0.044, OR=2.34, 95% CI=0.94-5.87). Other SNPs were not significantly associated with clinical covariates in prostate cancer (P > 0.05). CONCLUSIONS. rs339331 in the RFX6 gene may be associated with prostate cancer as a susceptibility locus in northern Chinese men.

Association of six susceptibility Loci with prostate cancer in northern chinese men.

BACKGROUND/AIM: Six prostate cancer (PCa) susceptibility loci were identified in a genome-wide association study (GWAS) in populations of European decent. However, the associations of these 6 single-nucleotide polymorphisms (SNPs) with PCa has remained tobe clarified in men in Northern China. This study aimed to explore the loci associated with PCa risk in a Northern Chinese population. METHODS: Blood samples and clinical information of 289 PCa patients and 288 controls from Beijing and Tianjin were collected. All risk SNPs were genotyped using polymerase chain reaction (PCR)-high resolution melting curve technology and gene sequencing. Associations between PCa and clinical covariates (age at diagnosis, prostate-specific antigen [PSA], Gleason score, tumor stage, and level of aggressiveness) and frequencies of alleles and genotypes of these SNPs were analyzed using genetic statistics. RESULTS: Among the candidate SNPs, 11p15 (rs7127900, A) was associated with PCa risk (P = 0.02, odds ratio [OR] = 1.64, 95% confidence interval [CI] = 1.09-2.46). Genotypes showed differences between cases and controls on 11p15 (rs7127900, A), 11q13 (rs7931342, T), and HNF1B (rs4430796, A) (P = 0.03, P = 0.01, and P = 0.04, respectively). The genotype TG on 11q13 (rs7931342, T) was positively associated with an increased Gleason score (P = 0.04, OR = 2.15, 95% CI = 1.02-4.55). Patients carrying TG on 17q24 (rs1859962, G) were negatively associated with an increased body mass index (BMI) (P = 0.03, OR = 0.44, 95% CI = 0.21-0.92) while those with AG on HNF1B (rs4430796, A) were more likely to have PSA increase (P = 0.002). CONCLUSION: Our study suggests that 11p15 (rs7127900, A) could be a susceptibility locus associated with PCa in Northern Chinese. Genotype TG on 11q13 (rs7931342, T) could be related to an increased Gleason score, AG on HNF1B (rs4430796, A) could be associated with PSA increase, and TG on 17q24 (rs1859962, G) could be negatively associated with an increased BMI in Chinese men with PCa.