Genetically Encoded Phosphine Ligand for Metalloprotein Design.

Phosphine ligands are the most important class of ligands for cross-coupling reactions due to their unique electronic and steric properties. However, metalloproteins generally rely on nitrogen, sulfur, or oxygen ligands. Here, we report the genetic incorporation of P3BF, which contains a biocompatible borane-protected phosphine, into proteins. This step is followed by a straightforward one-pot strategy to perform deboronation and palladium coordination in aqueous and aerobic conditions. The genetically encoded phosphine ligand P3BF should significantly expand our ability to design functional metalloproteins.

The effect of emotional uncertainty on attentional bias toward neutral infant faces in adults.

Recent studies have found that adults have stronger attentional bias toward neutral infant faces than emotional (positive or negative) infant faces. This phenomenon may derive from uncertainty over neutral expressions. To test this hypothesis, we recruited 176 participants to examine the relationship between their attentional bias toward neutral infant faces (with neutral adult faces as a comparison baseline) and their level of certainty in their appraisal of emotional valence through eye-tracking indices. The results showed that participants had a longer dwell time and higher fixation counts for infant faces than for adult faces and that a more uncertain appraisal of facial expressions positively predicted attentional bias toward neutral infant faces. Therefore, this study preliminarily demonstrates that emotional uncertainty heightens adults' attentional bias toward infant faces with neutral expressions.

Association of H3K9me3 with breast cancer prognosis by estrogen receptor status.

BACKGROUND: Cellular experiments revealed that a decreased histone H3 lysine 9 trimethylation (H3K9me3) level was associated with the upregulation of oncogenes in breast cancer cells. Moreover, the role of H3K9me3 in breast cancer was closely associated with estrogen receptor (ER) status. Therefore, we aimed to examine the prognostic value of H3K9me3 on breast cancer by ER status. The level of H3K9me3 in tumors were evaluated with tissue microarrays by immunohistochemistry for 917 women diagnosed with primary invasive breast cancer. Hazard ratios (HRs) and their 95% confidence intervals (CIs) for overall survival (OS) and progression-free survival (PFS) were estimated using Cox regression models. Interaction between H3K9me3 and ER on the prognosis was assessed on multiplicative scale. RESULTS: The level of H3K9me3 in tumor tissues was lower than that in adjacent tissues. The high level of H3K9me3 was associated with a better OS (HR = 0.43, 95% CI: 0.21-0.86) and PFS (HR = 0.49, 95% CI: 0.29-0.81) among only ER-positive but not ER-negative tumors. Moreover, the interaction between the level of H3K9me3 and ER status (negative and positive) on the prognosis was significant (Pinteraction = 0.011 for OS; Pinteraction = 0.022 for PFS). Furthermore, the ER-positive tumors were stratified by ER-low and ER-high positive tumors, and the prognostic role of H3K9me3 was significant among only ER-high positive patients (HR = 0.34, 95% CI: 0.13-0.85 for OS; HR = 0.47, 95% CI: 0.26-0.86 for PFS). CONCLUSIONS: Our study showed that the prognostic value of H3K9me3 on breast cancer was related to ER status and expression level, and the high level of H3K9me3 was associated with a better prognosis among ER-positive tumors, particularly ER-high positive tumors.

Prognostic value of glutaminase 1 in breast cancer depends on H3K27me3 expression and menopausal status.

Glutaminase 1 (GLS) is a therapeutic target for breast cancer; although GLS inhibitors have been developed, only a few subjects responded well to the therapy. Considering that the expression of histone H3 lysine 27 trimethylation (H3K27me3) and menopausal status was closely linked to GLS, we examined the effects of H3K27me3 and menopausal status on GLS to breast cancer prognosis. Data for 962 women diagnosed with primary invasive breast cancer were analyzed. H3K27me3 and GLS expression in tumors were evaluated with tissue microarrays by immunohistochemistry. Hazard ratios (HRs) and their 95% confidence intervals (CIs) for overall survival and progression-free survival were estimated using Cox regression models. Statistical interaction was assessed on multiplicative scale. There was a beneficial prognostic effect of GLS expression on overall survival for those with low H3K27me3 level (HR = 0.50, 95% CI: 0.20-1.28) but an adverse prognostic effect for those with high H3K27me3 level (HR = 3.90, 95% CI: 1.29-11.78) among premenopausal women, and the statistical interaction was significant (Pinteraction = 0.003). Similar pattern was further observed for progression-free survival (HR = 0.44, 95% CI: 0.20-0.95 for low H3K27me3 level, HR = 1.35, 95% CI: 0.74-2.48 for high H3K27me3 level, Pinteraction = 0.024). The statistical interaction did not occur among postmenopausal women. Our study showed that the prognostic effects of GLS on breast cancer correlated to the expression level of H3K27me3 and menopausal status, which would help optimize the medication strategies of GLS inhibitors.

Identification of epigenetic modifications mediating the antagonistic effect of selenium against cadmium-induced breast carcinogenesis.

The antagonistic effect of selenium (Se) against cadmium (Cd)-induced breast carcinogenesis was reported, but underlying mechanisms were unclear. The aim of this study was to identify the epigenetically regulated genes and biological pathways mediating the antagonistic effect. We exposed MCF-7 cells to Cd and Se alone or simultaneously. Cell proliferation was assessed by MTT assay, and differential epigenome (DNA methylation, microRNA, and long non-coding RNA) was obtained by microarrays. We cross-verified the epigenetic markers with differential transcriptome, and the ones modulated by Cd and Se in opposite directions were regarded to mediate the antagonistic effect. The epigenetically regulated genes were validated by using gene expression data in human breast tissues. We further assessed the biological functions of these validated genes. Our results showed that Se alleviated the proliferative effect of Cd on MCF-7 cell. A total of 10 epigenetically regulated genes were regarded to mediate the antagonistic effect, including APBA2, KIAA0895, DHX35, CPEB3, SVIL, MYLK, ZFYVE28, ABLIM2, GRB10, and PCDH9. Biological function analyses suggested that these epigenetically regulated genes were involved in multiple cancer-related pathways, such as focal adhesion and PI3K/Akt pathway. In conclusion, we provided evidence that Se antagonized the Cd-induced breast carcinogenesis via epigenetic modification and revealed the critical pathways.

Time-varying effects of FOXA1 on breast cancer prognosis.

PURPOSE: Results of previous studies on the associations between Forkhead box A1 (FOXA1) expression in breast cancer tissues and the prognosis varied depending on the follow-up durations. The present study would investigate whether there is a time-varying effect of FOXA1 in breast cancer tissues on the prognosis. METHODS: FOXA1 expressions were evaluated in 1041 primary invasive breast tumors with tissue microarrays by immunohistochemistry. Cox models with restricted cubic splines and Kaplan-Meier survival analysis were used to examine the associations between FOXA1 and the prognosis. Flexible parametric models were applied to explore the time-varying effect of FOXA1. RESULTS: Overall, the association between FOXA1 expression and the prognosis was not significant but varied on the time of follow-up. Compared to FOXA1 ≤ 270 of H-score, the hazard ratios (HRs) of death for those with 271-285 of FOXA1 expression increased from 0.35 (95% CI 0.14-0.86) at 6 months after diagnosis to 2.88 (95% CI 1.35-6.15) at 120 months with a crossover at around 36 months. Similar patterns were also observed for FOXA1 > 285 of H-score and for progression free survival (PFS). Moreover, when allowed both FOXA1 and estrogen receptor (ER) to change over time in the model (considering that ER had a similar time-varying effect), these time-varying effects remained for FOXA1 on both overall survival (OS) (P < 0.01) and PFS (P = 0.01) but were attenuated for ER (P = 0.13 for OS). CONCLUSIONS: This study revealed an independent time-varying effect of FOXA1 on breast cancer prognosis, which would provide an insight into the roles of FOXA1 as a marker of breast cancer prognosis and may help optimize the medication strategies.

Differential epigenetic profiles induced by sodium selenite in breast cancer cells.

OBJECTIVES: Selenium (Se) was a potential anticancer micronutrient with proposed epigenetic effect. However, the Se-induced epigenome in breast cancer cells was yet to be studied. METHODS: The profiles of DNA methylation, microRNA (miRNA), long non-coding RNA (lncRNA), and message RNA (mRNA) in breast cancer cells treated with sodium selenite were examined by microarrays. We verified the epigenetic modifications by integrating their predicted target genes and differentially expressed mRNAs. The epigenetically regulated genes were further validated in a breast cancer cohort by associating with tumor progression. We conducted a series of bioinformatics analyses to assess the biological function of these validated genes and identified the critical genes. RESULTS: The Se-induced epigenome regulated the expression of 959 genes, and 349 of them were further validated in the breast cancer cohort. Biological function analyses suggested that these validated genes were enriched in several cancer-related pathways, such as PI3K/Akt and metabolic pathways. Based on the degrees of expression change, hazard ratio difference, and connectivity, NEDD4L and FMO5 were identified as the critical genes. CONCLUSIONS: These results confirmed the epigenetic effects of sodium selenite and revealed the epigenetic profiles in breast cancer cells, which would help understand the mechanisms of Se against breast cancer.

Differential epigenetic and transcriptional profile in MCF-7 breast cancer cells exposed to cadmium.

Cadmium (Cd) has been confirmed to be associated with breast carcinogenesis, but the mechanism was not clarified yet. Given that epigenetic modification was speculated as underlying mechanism, we examined the differential epigenome caused by Cd in breast cancer cells. Profiles of DNA methylation, microRNA (miRNA), long non-coding RNA (lncRNA), and message RNA (mRNA) were derived from Cd-treated and untreated MCF-7 breast cancer cells by microarray. We identified 997 target genes epigenetically regulated by Cd through cross-verification with the differential epigenome and transcriptome, and 400 of them were further validated in a breast cancer cohort. Biological function analyses suggested that several pathways were involved in Cd-induced breast carcinogenesis, such as Wnt signaling, metabolism, and human papilloma virus (HPV) infection. TXNRD1 and CCT3 were further identified as the critical genes based on the degree of expression change, hazard ratio difference, and connectivity. The present study revealed that Cd epigenetically regulated several pathways involving in breast carcinogenesis, particularly the Wnt signaling and metabolic pathways, among which TXNRD1 and CCT3 might play critical roles. It was also suggested that Cd and HPV infection might jointly participate in breast tumorigenesis.

Associations of reproductive factors with breast cancer prognosis and the modifying effects of menopausal status.

Reproductive factors associated with breast cancer risk may also affect the prognosis. This study aimed to evaluate the associations of multiple reproductive factors with breast cancer prognosis and the modifying effects of menopausal status. We obtained data from 3805 breast cancer patients recruited between October 2008 and June 2016 in Guangzhou. The subjects were followed up until 30 June 2018. The hazard ratios (HRs) and 95% confidence intervals (95% CIs) were calculated using multivariate Cox models to estimate the associations. It was found that there were U-shaped patterns for the associations of age at first birth and durations from first/last birth to diagnosis with breast cancer prognosis. The adverse effects of old age at first birth [>30 years vs 23-30 years, HR (95% CI): 1.59 (1.01-2.50)] and long intervals from first [≥20 years vs 10-19 years, HR (95% CI): 1.55 (1.07-2.27)] or last [≥20 years vs 10-19 years, HR (95% CI): 1.63 (1.08-2.46)] birth to diagnosis on progression-free survival (PFS) were significantly more pronounced among premenopausal women. Additionally, long interval (>5 years) between first and second birth was associated with a better PFS [HR (95% CI): 0.64 (0.42-0.97)]. These results suggested that age at first birth, durations from first/last birth to diagnosis, and intervals between first and second birth should be taken into account when following the patients and assessing the prognosis of breast cancer, particularly for premenopausal patients. These findings would also have implications for further insight into the mechanisms of breast cancer development.

Patient and Care Delays of Breast Cancer in China.

PURPOSE: This study differentiates patient and care delays of breast cancer and explores the related factors as well as the associations with the prognosis in Guangzhou, a southern city of China. METHODS: A cohort of female incident breast cancer patients (n=1,551) was recruited from October 2008 to March 2012 and followed up until January 1, 2016 (n=1,374) in the affiliated hospitals of Sun Yat-sen University. The factors associated with patient and care delays were analyzed with multivariable logistic models. Cox proportional hazards regression models were constructed to estimate the impacts of the delays on the prognosis. RESULTS: There were 40.4% patient delay (≥3 months) and 15.5% care delay (≥1 month). The patient delay, but not the care delay, was significantly related to the clinical stage and consequently worsened the prognosis of breast cancer (hazard ratio, 1.45; 95% confidence interval, 1.09 to 1.91 for progression-free survival). The factors related to an increased patient delay included premenopausal status, history of benign breast disease, and less physical examination. CONCLUSION: Patient delay was the main type of delay in Guangzhou and resulted in higher clinical stage and poor prognosis of breast cancer. Screening for breast cancer among premenopausal women may be an effective way to reduce this delay.

[Response of photosynthesis traits of dominant plant species to different light regimes in the secondary forest in the area of Qiandao Lake, Zhejiang, China].

To understand the mechanisms driving community succession in the secondary forest surrounding Qiandao Lake, Zhejiang, China, we investigated seasonal dynamics of the diurnal variations of net photosynthetic rates, their responses to both light and CO2, and chlorophyll fluorescence parameters of four dominant plant species, i. e., Pinus massoniana, Castanopsis sclerophylla, Lithocarpus glaber and Cyclobalanopsis glauca in three natural light habitats, i. e., gap, edge and understory. In the three different light regimes, the daily mean values of the net photosynthetic rate (Pn) of P. massoniana and C. sclerophylla were significantly higher in summer than in the other seasons, while Pn of L. glaber and C. glauca was significantly higher in autumn than in the other seasons. In the forest gap and edge habitats, the annual mean values of the maximum net photosynthetic rate (Amax), the light saturation point (LSP), light compensation point (LCP) and dark respiration rate (Rd) of P. massoniana were the highest, followed by C. sclerophylla, and those of L. glaber and C. glauca were the lowest. In the understory habitat, the annual mean values of Amax and the apparent quantum yield (AQY) of C. glauca were the highest, followed by L. glaber and C. sclerophylla, and those of P. massoniana were the lowest. The annual mean values of the maximum rate of carboxylation (Vc max), maximum rate of electron transport (Jmax) and triose phosphate use rate (TPU) of P. massoniana were significantly higher than those of the other three plant species in the three different light regimes. During the four seasons, the photochemical maximum efficiency of PSII (Fv/Fm) of P. massoniana and C. sclerophylla in the forest gap habitat was significantly higher, while those of L. glaber and C. glauca in the understory habitat were significantly higher than in the other light regimes. The maximum values of Fv/Fm of P. massoniana and C. sclerophylla were the highest in summer, and those of L. glaber and C. glauca were the highest in autumn. It suggested that P. massoniana and C. sclerophylla were more suitable for habitats with high light intensities such as forest gaps, and L. glaber and C. glauca were more suitable for habitats with low light intensities such as the understory. During ecological succession, P. massoniana and C. sclerophylla would withdraw from the community with the increasing canopy density, and L. glaber and C. glauca would be the dominant species in the climax community.

[Spatial heterogeneity of soil organic carbon and total nitrogen in a monsoon evergreen broadleaf forest in Dinghushan, Guangdong, China].

Geostatistical techniques were used to quantify the spatial heterogeneity of soil organic carbon and total nitrogen of one monsoon evergreen broadleaf forest area in Dinghushan, Guangdong, China. The results demonstrated that a significant spatial autocorrelation existed between soil organic carbon and total nitrogen contents in the Dinghushan monsoon evergreen broadleaf forest, such that 93.6% and 53.7% of their total spatial heterogeneity originated from their spatial autocorrelation. This observation agreed with a traditional statistics analysis showing a significant linear correlation between soil organic carbon and total nitrogen, and also their spatial autocorrelation existed at a landscape level. The best fit from an exponential model showed that soil organic carbon had high degree of spatial heterogeneity at a scale of 17.4 m.

[Characteristics of dominant tree species stem sap flow and their relationships with environmental factors in a mixed conifer-broadleaf forest in Dinghushan, Guangdong Province of South China].

By the method of Granier' s thermal dissipation probe, the stem sap flow density of four dominant tree species (Pinus massoniana, Castanopsis chinensis, Schima superba, and Machilus kwangtungensis) in a mixed conifer-broadleaf forest in Dinghushan Reserve of South China was continuously measured in the dry season (November) and wet season (July) in 2010, and the environmental factors including air temperature, relative humidity, and photosynthetically active radiation (PAR) were measured synchronically, aimed to study the characteristics of the stem sap flow of the tree species in response to environmental factors. During the dry and wet seasons, the diurnal changes of the stem sap flow velocity of the tree species all presented a typical single-peak curve, with high values in the daytime and low values in the nighttime. The average and maximum sap flow velocities and the daily sap flow flux of broad-leaved trees (C. chinensis, S. superba, and M. kwangtungensis) were significantly higher than those of coniferous tree (P. massoniana), and the maximum sap flow velocity of P. massoniana, C. valueschinensis, S. superba, and M. kwangtungensis was 29.48, 38.54, 51.67 and 58.32 g H2O x m(-2) x s(-1), respectively. A time lag was observed between the sap flow velocity and the diurnal variations of PAR, vapor pressure deficiency, and air temperature, and there existed significant positive correlations between the sap flow velocity and the three environmental factors. The PAR in wet season and the air temperature in dry season were the leading factors affecting the stem sap flow velocity of the dominant tree species.