Tumor-Derived Oxidative Stress Triggers Ovarian Follicle Loss in Breast Cancer

Breast cancer is a common indication for ovarian cryopreservation. However, whether the grafting ovarian tissue meets functional requirements, as well as the need for additional interventions, remains unclear. The current study demonstrates abnormal serum hormones in breast cancer in humans and breast cancer cell line-derived tumor-bearing mice, and for the first time shows tumor-induced loss of primordial and growing follicles and the number of follicles being lost to either growth or atresia. A gene signature of tumor-bearing mice demonstrates the disturbed regulatory network of steroidogenesis, which links to mitochondria dysfunction in oocytes and granulosa cells via the phosphatidylinositol 3-kinase signaling pathway. Notably, increased reactive oxygen species are identified in serum and ovarian tissues in tumor-bearing mice. Furthermore, supplementation with vitamin C promotes follicular quiescence, repairing tumor-induced follicle loss via inactivation of the phosphatidylinositol 3-kinase-Akt-mammalian target of rapamycin pathway, indicating that antioxidants should be a potential fertility therapy to achieve more numbers of healthy follicles ready for ovarian cryopreservation.

[The efficacy of eltrombopag plus cyclosporine A in patients with transfusion-dependent non-severe aplastic anemia: a retrospective study from single center]

The main purpose of our study was to evaluate the efficacy and safety of eltrombopag plus cyclosporine A (CsA) in transfusion-dependent non-severe aplastic anemia(TD-NSAA). The clinical characteristics of 13 TD-NSAA patients who received initial treatment of eltrombopag plus CsA from 2019 to 2021 were retrospectively analyzed. The 3-month overall hematological response (OR) rate was 12/13. Until the end of follow-up, 12 patients responded, among whom 2 patients reached complete response (CR) and 9 patients reached partial response (PR) and 1 with HR. Paroxysmal nocturnal hemoglobinuria (PNH) developed in one patient at 6 months after treatment. Five of thirteen patients reported mild adverse reactions, which were all manageable. Compared with historical data, the combination of eltrombopag with CsA is an effective regimen in patients with TD-NSAA.

Surfactant assisted Cr-metal organic framework for the detection of bisphenol A in dust from E-waste recycling area

Due to their highly porous structures, metal organic framework materials are widely used in analytic areas. In this paper, Cr-metal organic framework (MIL-101(Cr)) modified electrode was prepared and then was used as electrochemical sensor for the detection of bisphenol A (BPA). By using one kind of surfactant of cetyltrimethylammonium bromide (CTAB), the analytic performances of MIL-101 (Cr) towards BPA detection were greatly improved. Compared with pure MIL-101 (Cr), the differential pulse voltammetry (DPV) behavior of CTAB/MIL-101 (Cr) was improved 3.0 times in the presence of BPA. The hydrophobic long chain alkanes of CTAB can improve the enrichment and electrochemical oxidation for BPA. The CTAB/MIL-101 (Cr) sensor exhibited a linear range from 20 to 350 nM and a low detection limit of 9.95 nM (LOD = 3s_b/S) and showed good reproducibility, stability and selectivity. Finally, real samples of dusts from E-waste recycling area in South China were collected and the CTAB/MIL-101 (Cr) sensor demonstrated satisfactory results for BPA detection from these dust samples.

Photo-electrochemical detection of dopamine in human urine and calf serum based on MIL-101 (Cr)/carbon black

A new photo-electrochemical sensor based on MIL-101(Cr) MOF/carbon black (CB) is fabricated and characterized. By using differential pulse voltammetry, dopamine (DA) can be effectively detected using a photo-electrochemical MIL-101(Cr)/CB sensor under visible light. The CB acts as the electron bridge to combine with the large specific surface area and photo-catalytic feature of MOF, which contribute to the improvements of sensitivity of DA detection. The concentration of the catalyst, pH value, accumulation potential, and accumulation time were also optimized. Furthermore, the electrochemical performances of MIL-101(Cr)/CB sensor was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scan rate, electrochemically active surface area (ECSA), and amperometric responses. A detection limit of 0.38 nM (LOD = 3 s_b/S, s_b = 0.028) and a working range of 1 nM to 2.22 μM has been achieved. The MIL-101(Cr)/CB sensor exhibits excellent reproducibility, stability, and selectivity and also has satisfactory recovery rate for the analysis of real samples including calf serum and human urine. Graphical abstract.

Size-dependent influence of NOx on the growth rates of organic aerosol particles

Atmospheric new-particle formation (NPF) affects climate by contributing to a large fraction of the cloud condensation nuclei (CCN). Highly oxygenated organic molecules (HOMs) drive the early particle growth and therefore substantially influence the survival of newly formed particles to CCN. Nitrogen oxide (NOx) is known to suppress the NPF driven by HOMs, but the underlying mechanism remains largely unclear. Here, we examine the response of particle growth to the changes of HOM formation caused by NOx. We show that NOx suppresses particle growth in general, but the suppression is rather nonuniform and size dependent, which can be quantitatively explained by the shifted HOM volatility after adding NOx. By illustrating how NOx affects the early growth of new particles, a critical step of CCN formation, our results help provide a refined assessment of the potential climatic effects caused by the diverse changes of NOx level in forest regions around the globe.

[Analysis of SLC25A13 gene mutations and prenatal diagnosis for 20 families affected with citrin deficiency]

OBJECTIVE

To detect mutations of SLC25A13 gene in 20 families affected with citrin deficiency and provide prenatal diagnosis for them.

METHODS

The 20 probands and their parents were subjected to high-frequency mutation screening combined with Sanger sequencing. After confirming the genotype of each pedigree, genetic counseling and prenatal diagnosis were performed for their subsequent pregnancies.

RESULTS

Biallelic pathogenic mutations of the SLC25A13 gene were identified in all probands. These included three deletions (c.851del4, c.1092_1095delT, and c.495delA), two splice-site mutations (IVS6+5G to A and IVS11+1G to A), two nonsense mutations (c.775C to T (p.Q259X) and c.72T to A (p.Y24X)), one duplication mutation (c.1638_1660dup), one insertion (IVSl6ins3kb), and one missense mutation (c.1775A to C (p.Q592P)). Among 24 fetuses undergoing prenatal diagnosis, 8 had normal genotypes, 11 were mutation carriers, while 5 harbored biallelic mutations. Those with wild type alleles or heterozygous SLC25A13 mutations were delivered. Two fetuses harboring homozygous c.851del4 mutations were also delivered. Three fetuses harboring biallelic mutations were terminated.

CONCLUSION

Analysis of SLC25A13 gene mutations in families affected by citrin deficiency can provide evidence for molecular diagnosis and facilitate genetic counseling and prenatal diagnosis for the subsequent pregnancy, which can effectively reduce the risk of birth of further affected children.

[Genotype and phenotype analysis of a child with partial 18q deletion syndrome]

OBJECTIVE

To explore the genotype-phenotype correlation of a child with chromosome 18q deletion syndrome.

METHODS

G-banded karyotyping, single nucleotide polymorphism array (SNP array) and fluorescence in situ hybridization (FISH) were performed on the child with abnormal phenotypes. Genotype-phenotype correlation was explored following accurate mapping of the breakpoints on chromosome 18q. SNP array was also performed on the genome DNA derived from peripheral venous blood samples from both parents.

RESULTS

Chromosomal analysis revealed that the child has a karyotype of 46, XY, del(18) (q23). SNP array analysis detected a 9.855 Mb deletion (chr18: 68 158 880-78 014 123) at 18q22.2q23. Mapping of the breakpoints suggested that the deletion has overlapped with that of distal chromosome 18q deletion syndrome and encompassed several critical regions for this syndrome. SNP array performed on parental samples suggested that the 18q22.2q23 deletion was de novo in origin. FISH analysis of peripheral blood sample from the child confirmed the presence of 18qter deletion.

CONCLUSION

The phenotype of this child may be attributed to the deletion of distal 18q22.2q23, which has encompassed several critical regions for the 18q deletion syndrome.

Cucurbitacin B induces rapid depletion of the G-actin pool through reactive oxygen species-dependent actin aggregation in melanoma cells

Cucurbitacin B (CuB), a triterpenoid compound isolated from Cucurbitaceae plants, has been reported as a promising anti-cancer agent, yet its action mechanism is still controversial. In this study, we explored the potential mechanism of CuB in murine B16F10 melanoma cells. Anti-proliferation and anti-invasion effects were assessed in cultured cells, and in vivo anti-tumor activity was evaluated in a murine subcutaneous melanoma model. Flow cytometry was adopted to analyze cell cycle distribution and reactive oxygen species (ROS) levels. Actin levels were determined by western blot analysis, and the profiles of differential expressed proteins were identified by a quantitative proteomic approach. The results showed that CuB exerted inhibitory effects on cell proliferation, colony formation, as well as migration and invasion potential of the melanoma cells. The growth of subcutaneous melanoma was significantly inhibited in mice treated with CuB when compared with control group. Furthermore, CuB treatment caused rapid cell membrane blebbing and deformation, and induced G(2)/M-phase arrest and formation of multiploid cells. Notably, the G-actin pool was rapidly depleted and actin aggregates were formed quickly after CuB treatment. A number of cytoskeleton-regulatory proteins were differentially regulated. Blockage of ROS production significantly reduced the G-actin depletion ability and the anti-tumor activity of CuB. These findings indicate that CuB induces rapid depletion of the G-actin pool through ROS-dependent actin aggregation in melanoma cells, which may at least partly account for its anti-tumor activity.

Histone deacetylase inhibitor valproic acid sensitizes B16F10 melanoma cells to cucurbitacin B treatment

Cucurbitacin B (CuB) is reported to have anti-proliferation effects on a variety of tumors including melanoma, and more effective regimens by combination of this agent with others are under investigation. In this study, the anti-melanoma effect of CuB as a single agent and in combination with valproic acid (VPA), an inhibitor of histone deacetylase (HDAC), was evaluated in B16F10, a mouse melanoma cell line. The results demonstrated that CuB inhibited the proliferation of the cell line in a dose-dependent manner. However, it was likely that a pro-survival compensatory response, involving the induction of autophagy and upregulation of anti-apoptotic Bcl-2 protein, was induced by CuB treatment, which might greatly decrease the cytotoxicity of this agent. Supporting this, the melanoma cells were found to be more sensitive to the combination of CuB with chloroquine, a well-known autophagy inhibitor. And CuB-induced autophagy was associated with c-Jun N-terminal kinase (JNK) activation, at least partly, since inhibition of JNK activity by SP600125 could alleviate the autophagy. When CuB was combined with VPA, the two drugs showed synergistic cytotoxicity by induction of cell apoptosis. Moreover, the multiploidization effect of CuB was also suppressed in the presence of VPA. In contrast to the transient activation of JNKs by CuB, the combination of CuB and VPA resulted in prolonged JNK activation, although at low level after 4 h. Our results demonstrated that HDAC inhibitor VPA can sensitize B16F10 cells to CuB treatment through induction of apoptotic pathway.

High level expression of HLA-A*0203-BSP fusion protein in Escherichia coli and construction of soluble HLA-A*0203 monomer and tetramer loaded with Epstein-Barr virus peptide

Major histocompatibility complex (MHC) tetramer technology is critical for characterization of antigen-specific T cells. In the present study we reported the successful generation of HLA-A*0203 tetramer loaded with Epstein-Barr virus EBNA3(596-604) peptide (SVRDRLARL, SVR). Prokaryotic expression vector for the ectodomain of the heavy chain of HLA-A*0203 fused with a BirA substrate peptide (HLA-A*0203-BSP) was constructed and the expression conditions of the fusion protein in Escherichia coli (E. coli) were optimized. The fusion protein was highly expressed in inclusion bodies within E. coli. It was then refolded in the presence of beta2-microglobulin and SVR peptide to form a soluble HLA-A*0203-SVR monomer. After biotinylation with BirA, the monomer was purified by anion-exchange chromatography and its purity was up to 95%. The tetramer was then formulated by mixing the biotinylated monomer with streptavidin-PE at a ratio of 4:1. Flow cytometry showed that this tetramer could specifically react with antigen-specific CD8+ T cells, indicating that it was biologically functional. These results provide a foundation for further characterization of antigen-specific CD8+ T cells from HLA-A*0203 subjects.

Preparation and identification of HLA-A*1101 tetramer loading with human cytomegalovirus pp65 antigen peptide

MHC/peptide tetramer technology has been widely used to study antigen-specific T cells, especially for identifying virus-specific CD8+ T cells in humans. The tetramer molecule is composed of HLA heavy chain, beta2-microglobulin (beta2m), an antigenic peptide, and fluorescent-labeled streptavidin. To further investigate the HLA-A*1101-restricted CD8+ T cell responses against human cytomegalovirus (HCMV), we established an approach to prepare HLA-A*1101 tetramer complexed with a peptide from HCMV. The cDNA encoding HLA-A*1101 heavy chain was cloned and the prokaryotic expression vector for the ectodomain of HLA-A*1101 fused with a BirA substrate peptide (HLA-A*1101-BSP) at its carboxyl terminus was constructed. The fusion protein was highly expressed as inclusion bodies under optimized conditions in Escherichia coli. Moreover, HLA-A*1101-BSP protein was refolded in the presence of beta2m and an HCMV peptide pp65(16-24) (GPISGHVLK, GPI). Soluble HLA-A*1101-GPI monomer was biotinylated and purified to a purity of 95%, which was subsequently combined with streptavidin to form tetramers at a yield of > 80%. The HLA-A*1101-GPI tetramers could bind to virus-specific CD8+ T cells, suggesting soluble HLA-A*1101-GPI tetramers were biologically functional. This study provides the basis for further evaluation of HLA-A*1101-restricted CD8+ T cell responses against HCMV infection.

Preparation and characterization of HLA-A*0201 tetramer loaded with IE-1316-324 antigenic peptide of human cytomegalovirus

Major histocompatibility complex (MHC) class I tetramer technology has become the central technique for analyzing antigen-specific CD8(+) T cell responses and it has been widely used to explore the differentiation and formation of memory CD8(+) T cells. Previously, a simplified and efficient procedure for preparing high quality HLA-A*0201 tetramers has been established in our lab and the tetramers loaded with HCMV peptide pp65(495-503) has been successfully applied to investigate HCMV-specific CD8(+) T cells in Chinese populations. Using similar procedure we reported here the construction of HLA-A*0201 tetramer loaded with another dominant epitope derived from immediate early (IE)-1(316-324) (VLEETSVML, VLE) of HCMV (A2-VLE) and characterization of this tetramer. After A2-VLE monomer was prepared and purified, its tetramer was then formed at a yield of 83%. The optimized amount of A2-VLE tetramer for staining 100 microl whole blood was 0.5 microg with incubation at 4 degrees C for 1 h. Furthermore, the dissociation constant of the tetramer binding to the specific CD8(+) T cells of one HLA-A2(+) donor was estimated to be 32.7 nmol/L, which is markedly higher than that of MHC monomer. The construction of A2-VLE tetramer provides an alternative choice for investigating HCMV-specific CD8(+) T cell responses and will deepen our understanding of the differentiation and formation of HCMV-specific memory CD8(+) T cells.

GM1 ganglioside regulates the proteolysis of amyloid precursor protein

Plaques containing amyloid beta-peptides (Abeta) are a major feature in Alzheimer's disease (AD), and GM1 ganglioside is an important component of cellular plasma membranes and especially enriched in lipid raft. GM1-bound Abeta (GM1/Abeta), found in brains exhibiting early pathological changes of AD including diffuse plaques, has been suggested to be involved in the initiation of amyloid fibril formation in vivo by acting as a seed. However, the role of GM1 in amyloid beta-protein precursor (APP) processing is not yet defined. In this study, we report that exogenous GM1 ganglioside promotes Abeta biogenesis and decreases sAPPalpha secretion in SH-SY5Y and COS7 cells stably transfected with human APP695 cDNA without affecting full-length APP and the sAPPbeta levels. We also observe that GM1 increases extracellular levels of Abeta in primary cultures of mixed rat cortical neurons transiently transfected with human APP695 cDNA. These findings suggest a regulatory role for GM1 in APP processing pathways.

Analysis of polycyclic aromatic hydrocarbons in the particulate phase of cigarette smoke using a gas chromatographic-high-resolution mass spectrometric technique

A new procedure is developed for the extraction of polycyclic aromatic hydrocarbons (PAHs) from the particulate phase of cigarette smoke. The procedure applies solid-phase extraction using a Bond Elut CH cartridge as a sample preparation step. The efficiency of the cleanup procedure is verified using a gas chromatographic (GC)-high-resolution mass spectrometric (MS) technique, proving that no interference occurs in the PAHs' determination. The efficient cleanup allows GC detection using either high- or low-resolution MS detection. Enhanced sensitivity is obtained using GC-MS and selected ion monitoring. This new technique has several advantages over other reported techniques. The method is simple and robust and has good repeatability and accuracy. The estimated detection limit is 0.1 ng/cigarette for benzo[a]pyrene. In addition to that, the recovery from the smoke pad in which the smoke is collected is approximately 97% for all PAHs. Results for the PAH analyses for 1R5F, 1R4F, and 1R3 Kentucky reference cigarettes are reported in this study. These results provide useful evidence for clarifying the controversy about previously reported data.