[Expression of SOX10 and GATA3 in breast cancer and their significance].

Objective: To investigate the expression characteristics of SOX10 and GATA3 in breast cancer and the value of their combination. Methods: A total of 360 breast cancer specimens with SOX10 immunohistochemical staining were collected from the Department of Pathology in Shenzhen People's Hospital from 2018 to 2021, including 268 cases with simultaneous SOX10 and GATA3 staining. The expression of SOX10 and GATA3 in primary and metastatic breast cancer was detected, and the correlations between SOX10 and GATA3 and the molecular types and clinicopathological features of breast cancer were compared, and the distribution differences among each group were statistically analyzed. Results: The overall expression of SOX10 and GATA3 in breast cancer were 25.8%(93/360) and 81.7%(219/268), and that in triple negative breast cancer (TNBC) were 83.3%(80/96) and 42.7%(32/75), respectively. SOX10 was strongly associated with TNBC (P<0.001), whereas GATA3 was highly expressed in luminal A, luminal B and HER2 over expression breast cancers (P<0.001). The expression of SOX10 and GATA3 was negatively correlated in TNBC, and the combined expression rates of SOX10 and GATA3 in breast cancer and TNBC could reach 97.8% (262/268) and 94.7%(71/75), respectively. In addition, the expression of SOX10 was closely correlated with high histological grade, high Ki-67 proliferation index and lymph node metastasis, and negatively correlated with AR. The expression of GATA3 was correlated with low histological grade and lymph node metastasis, and positively correlated with AR, and the difference was statistically significant. Conclusions: SOX10 is a sensitive marker of TNBC, while GATA3 is highly expressed in non-triple negative breast cancer. The two complementary, combined application of SOX10-GATA3 can improve the detection rate of breast cancer, especially TNBC. SOX10 is associated with malignant characteristics of the tumor, suggesting that SOX10 can be used as a prognostic marker and potential therapeutic target for breast cancer.

FMNL2 destabilises COMMD10 to activate NF-κB pathway in invasion and metastasis of colorectal cancer.

BACKGROUND: Diaphanous-related formins (DRFs), actin necleator, have been known to participate in the progression of cancer cells. We previously reported that FMNL2 (Formin-like2), a member of DRFs, was a positive regulator in colorectal cancer (CRC) metastasis, yet proteins and pathways required for the function of this pro-invasive DRFs remain to be identified. METHODS: The relationship between FMNL2 and COMMD10 was examined using Co-IP, GST pull-down, immunofluorescence and in vitro ubiquitination assay. The in vitro and in vivo function of COMMD10 in CRC was evaluated using CCK-8 proliferation assay, plate colony formation, cell cycle, apoptosis and animal models. The inhibition of NF-κB signalling by COMMD10 was detected using dual-luciferase reporter assay and western blotting. Co-IP, GST pull-down and nuclear protein extraction assay were performed to evaluate the effect on p65 by COMMD10. Real-time PCR and western blotting were performed to detect expressions of FMNL2, COMMD10 and p65 in paired tissues. RESULTS: FMNL2 targets COMMD10 for ubiquitin-mediated proteasome degradation in CRC cells. COMMD10 targets p65 NF-κB (nuclear factor-κB) subunit and reduces its nuclear translocation, thereby leading to the inactivation of NF-κB pathway and suppression of CRC invasion and metastasis. Inhibition of NF-κB signalling by COMMD10 is necessary for FMNL2-mediated CRC cell behaviours. Downregulation of COMMD10 predicts poor prognosis of CRC patients. The expressions of FMNL2, COMMD10 and p65 are highly linked in CRC tissues. CONCLUSIONS: These data demonstrate that the FMNL2/COMMD10/p65 axis acts as a critical regulator in the maintenance of metastatic phenotypes and is strongly associated with negative clinical outcomes.

Quantitative proteomic profiling of renal tissue in human chronic rejection biopsy samples after renal transplantation.

INTRODUCTION: Chronic rejection (CR) is the leading cause of late renal transplant failure and is characterized by a relatively slow but progressive loss of renal function in combination with proteinuria and hypertension >3 months after transplantation. To identify and quantify the protein profiles in renal tissues of CR patients, we used isotope tagging for relative and absolute quantification (iTRAQ)-based proteomic technology to perform global protein expression analyses in CR patients and control subjects. MATERIALS AND METHODS: After protein extraction, quantitation, and digestion, samples were labeled with iTRAQ reagents and then separated by strong cation exchange and high-performance liquid chromatography. The fractions were further analyzed by tandem mass spectrometry. ProteinPilot version 4.0 software and the Swiss-Prot human database were applied for statistical analysis and database searching, respectively. Differentially expressed proteins were subjected to bioinformatic analysis by using the Gene Ontology database and the Kyoto Encyclopedia of Genes and Genomes database to further characterize their potential functional roles and related pathways in CR. RESULTS: In total, 1857 distinct proteins (confidence >95%, ρ < .05) were identified and quantified. Using a strict cutoff value of 1.5-fold for expressed variation, 87 proteins showed significant differences in expression between the CR and control groups; 53 were up-regulated and 34 were down-regulated. The differentially expressed proteins were mainly involved in protein binding, structural molecule activity, and extracellular matrix structural constituent. Several proteins, such as the alpha-1 chain of collagen type IV and integrin alpha-1, may play roles in the pathogenesis of CR and were implicated in the extracellular matrix-receptor interaction pathway. CONCLUSIONS: This study is the first to focus on iTRAQ-based quantitative proteomic characterization of renal tissue in CR. These insights may broaden our understanding of the molecular mechanisms underlying CR and provide potential biomarker candidates for future diagnostics.

Sensitized airway smooth muscle plasticity and hyperreactivity: a review.

To help elucidate the mechanisms underlying asthmatic bronchospasm, the goal of our research has been to determine whether airway smooth muscle (ASM) hyperreactivity was the responsible factor. We reported that in a canine model of asthma, the shortening capacity (DeltaLmax) and velocity (Vo) of in vitro sensitized muscle were significantly increased. This increase was of sufficient magnitude to account for 75% narrowing of the in vivo airway, but maximal isometric force was unchanged. This last feature has been reported by others. Under lightly loaded conditions, ASM completes 75% of its isotonic shortening within the first 2 s. Furthermore, 90% of the increased shortening of ragweed pollen-sensitized ASM (SASM), compared with control (CASM), is complete within the first 2 s. The study of shortening beyond this period will apparently not yield much useful information, and studies of isotonic shortening should be focused on this interval. Although both CASM and SASM showed plasticity and adaptation with respect to isometric force, neither muscle type showed a difference in the force developed in these phases. During isotonic shortening, no evidence of plasticity was seen, but the equilibrated SASM showed increased DeltaLmax and Vo of shortening. Molecular mechanisms of changes in Vo could result from changes in the kinetics of the myosin heavy chain ATPase. Motility assay, however, showed no changes between CASM and SASM in the ability of the purified myosin molecule (SF1) to translocate a marker actin filament. On the other hand, we found that the state of activation of the ATPase by phosphorylation of smooth muscle myosin light chain (molecular mass 20,000 Da) was greater in the SASM. This would account for the increased Vo. Investigating the signalling pathway, we found that whereas [Ca2+]i increased in both isometric and isotonic contraction, there was no significant difference between CASM and SASM. The content and activity of calmodulin were also not different between the 2 muscles. Nevertheless, we did find that content and total activity of smooth muscle myosin light chain kinase (smMLCK) and the abundance of its message were greater; this would explain the increased MLC20 phosphorylation. The binding affinity between Ca2+ and calmodulin and between 4 Ca2+ calmodulin and smMLCK remains to be studied. We conclude that SASM shows increased isotonic shortening capacity and velocity. It also shows increased content and total activity of smMLCK, which is consistent with the increased shortening. Plasticity produced by oscillation is not seen in the shortening muscle, although it is seen with respect to force development. It did not modulate the behaviour of the sensitized muscle.

Transforming growth factor-beta as a differentiating factor for cultured smooth muscle cells.

The aim of the present study was to determine whether the development of supercontractile smooth muscle cells, contributing to the nonspecific hyperreactivity of airways in asthmatic patients, is due to transforming growth factor (TGF)-beta. In cultured smooth muscle cells starved by removal of 10% foetal bovine serum for 7 days, growth arrest was seen; 30% became elongated and demonstrated super contractility. Study of conditioned medium suggested that the differentiating factor was TGF-beta. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) was carried out on conditioned medium from the arrested cells. Two protein bands were identified as matrix metalloproteinase (MMP)-2 and TGF-beta1. To determine second messenger signalling by SMAD2, Western blotting and confocal microscopy were employed. Conditioned medium from arrested cultures showed the presence of MMP-2 and TGF-beta1, as revealed by SDS-PAGE; 68- and 25-kDa bands were seen. Differentiation was confirmed by upregulation of marker proteins, smooth muscle type myosin heavy chain and myosin light chain kinase. Confirmation was obtained by downregulating these proteins with decorin treatment, which reduces the levels of active TGF-beta and an adenoviral dominant-negative vector coding for a mutated type II TGF-beta-receptor. Activation of second messenger signalling was demonstrated immunocytochemically by the presence of phosphorylated SMAD2 and SMAD4. Transforming growth factor-beta is likely to be the differentiating factor responsible for the development of these supercontractile smooth muscle cells. The development of such cells in vivo after cessation of an asthmatic attack could contribute to the nonspecific hyperreactivity of airways seen in patients.

Functional inactivation of the IGF-I receptor delays differentiation of skeletal muscle cells.

Skeletal myoblasts are inherently programmed to leave the cell cycle and begin the differentiation process following removal of exogenous growth factors. Serum withdrawal results in a marked induction of IGF production which is essential for skeletal muscle differentiation in vitro. However, the potential role of the tyrosine kinase IGF-I receptor (thought to be the principal mediator of both IGF-I and II signaling in skeletal muscle) in the decision of myoblasts to begin differentiation following serum withdrawal is unknown. To explore the role of the IGF-I receptor in this decision by skeletal myoblasts, we functionally inactivated endogenous IGF-I receptors in mouse C2C12 cells using a dominant negative, kinase-inactive IGF-I receptor in which the ATP-binding site lysine (K) at residue 1003 has been mutated to alanine (A). Cell lines with the greatest degree of mutant IGF-I receptor expression (A/K cells) demonstrated functional inactivation of endogenous IGF-I receptors as determined by their impaired ability to phosphorylate the principal substrate of the IGF-I receptor, IRS-1, in response to treatment with IGF-I. In addition, the proliferative response of myoblasts to IGF-I was completely abolished in A/K cells. Following withdrawal of exogenous growth factors, A/K cells demonstrated a marked delay in the induction of the gene expression of myogenin, a skeletal muscle-specific transcription factor essential for differentiation, and a subsequent delay in the induction of muscle creatine kinase activity. Delayed differentiation in A/K cells was associated with prolonged phosphorylation of the cell cycle regulatory retinoblastoma (Rb) protein; it is the un- (or hypo-) phosphorylated form of Rb which is known to promote differentiation in skeletal myoblasts. Thus, the IGF-I receptor regulates the timing of myoblast differentiation induced by serum withdrawal. The delayed differentiation of skeletal myoblasts with functionally inactive IGF-I receptors may result, at least in part, from delayed induction of myogenin gene expression and prolonged phosphorylation of the Rb protein.

Opposing early inhibitory and late stimulatory effects of insulin-like growth factor-I on myogenin gene transcription.

Insulinlike growth factors (IGFs) stimulate skeletal muscle cell differentiation in association with an increase in the mRNA of myogenin, a member of the MyoD family of skeletal muscle-specific transcription factors that plays an essential role in the differentiation process. However, this is a relatively late effect, requiring treatment periods of >24 h. In contrast, IGFs initially inhibit skeletal muscle cell differentiation, associated with a marked reduction in myogenin mRNA. The mechanisms by which IGF-I initially inhibits and subsequently stimulates myogenin expression are unknown. In the first 24 h, we find that IGF-I inhibits myogenin gene transcription by >80% but has no effect on myogenin mRNA stability. Similarly, in the first 24 h, IGF-I markedly inhibits myogenin promoter activity; the sequence -145 to -9 of the myogenin gene is sufficient to confer this inhibitory effect of IGF-I. In contrast, 48 h of treatment with IGF-I results in an increase in myogenin promoter activity that parallels the increase in myogenin steady-state mRNA. This increase in promoter activity is completely prevented in constructs lacking the sequence -1,565 to -375 of the myogenin gene. These data indicate that the early inhibitory and late stimulatory effects of IGF-I on myogenin expression are mediated at the level of transcription, and that these time-dependent, opposing effects of IGF-I on myogenin transcription are mediated by distinct regions of the myogenin gene. To our knowledge, this is the first demonstration of a gene whose promoter activity is initially inhibited and subsequently stimulated by IGF-I.

A study of conserved in-loop and out-of-loop glycine residues in the large subunit of ribulose bisphosphate carboxylase/oxygenase by directed mutagenesis.

The replacement of all 22 completely conserved glycine residues in the large subunit of ribulose bisphosphate carboxylase/oxygenase from Anacystis nidulans by directed mutagenesis is described. In each beta/alpha barrel of the large subunit there are 12 completely conserved glycines in six of eight loops at the C-termini of eight beta-strands and four in loops at N-terminal ends of the beta-strands. Two completely conserved glycines are also in each beta/alpha barrel backbone and four more are in a large N-terminal portion preceding the barrel in a given L subunit. Substitution of glycines in loops that are C-terminal to beta-strands by proline was more deleterious to carboxylase activity than that by alanine supporting the postulates that these loops contribute to catalysis and substrate binding and that in some cases the glycines may serve as hinges enabling movement of the loops. In contrast, substitution of glycines at the N-terminal ends of beta-strands in the beta/alpha barrel more often led to failure to detect L subunits or their assembly into L8S8 complex. Substitution of these and the other conserved glycines by proline was more deleterious to carboxylase activity than by alanine in enzymes that assembled.

Opposing early and late effects of insulin-like growth factor I on differentiation and the cell cycle regulatory retinoblastoma protein in skeletal myoblasts.

The mechanisms by which insulin-like growth factors (IGFs) can be both mitogenic and differentiation-promoting in skeletal myoblasts are unclear because these two processes are believed to be mutually exclusive in this tissue. The phosphorylation state of the ubiquitous nuclear retinoblastoma protein (Rb) plays an important role in determining whether myoblasts proliferate or differentiate: Phosphorylated Rb promotes mitogenesis, whereas un- (or hypo-) phosphorylated Rb promotes cell cycle exit and differentiation. We hypothesized that IGFs might affect the fate of myoblasts by regulating the phosphorylation of Rb. Although long-term IGF treatment is known to stimulate differentiation, we find that IGFs act initially to inhibit differentiation and are exclusively mitogenic. These early effects of IGFs are associated with maintenance of Rb phosphorylation typical of proliferating cells; upregulation of the gene expression of cyclin-dependent kinase 4 and cyclin D1, components of a holoenzyme that plays a principal role in mediating Rb phosphorylation; and marked inhibition of the gene expression of myogenin, a member of the MyoD family of skeletal muscle-specific transcription factors that is essential in muscle differentiation. We also find that IGF-induced inhibition of differentiation occurs through a process that is independent of its mitogenic effects. We demonstrate, thus, that IGFs regulate Rb phosphorylation and cyclin D1 and cyclin-dependent kinase 4 gene expression; together with their biphasic effects on myogenin expression, these results suggest a mechanism by which IGFs are initially mitogenic and subsequently differentiation-promoting in skeletal muscle.

Skeletal muscle cell-derived insulin-like growth factor (IGF) binding proteins inhibit IGF-I-induced myogenesis in rat L6E9 cells.

The insulin-like growth factors (IGFs) stimulate the differentiation of skeletal muscle cells. IGF binding proteins (IGFBPs), which are expressed by skeletal muscle cells, may enhance or inhibit IGF actions. To explore the role of skeletal muscle-derived IGFBPs in IGF-induced myogenesis, we compared the differentiation-inducing effects of IGF-I and des(1-3)IGF-I in rat L6E9 skeletal myoblasts. Des(1-3)IGF-I is a naturally occurring IGF-I analog with markedly reduced affinity for IGFBPs but with an affinity for the IGF-I receptor that is comparable to that for native IGF-I. We find that rat L6E9 cells produce principally IGFBP-4 and BP-6, with a minor component of IGFBP-5. Both IGFBP-4 and BP-6 accumulate during differentiation and increase further in response to IGF-I or des(1-3)IGF-I treatment. We find that an IGF-I analog with reduced affinity for IGFBPs is significantly more potent than native IGF-I in stimulating myogenesis (as assessed by myogenin messenger RNA abundance and muscle creatine kinase activity), indicating that IGFBPs expressed by skeletal muscle cells inhibit differentiation induced by IGF-I. In view of the relative abundance of IGFBP-4, its relatively high affinity for IGF-I and the low affinity of IGFBP-6 for IGF-I, it is likely that the inhibitory effect of rat skeletal muscle-derived IGFBPs on IGF-I-induced myogenesis is mediated principally by IGFBP-4.

Liver glucose transporter: a basolateral protein in hepatocytes and intestine and kidney cells.

The "liver" isoform of the facilitated diffusion glucose transporter is expressed predominantly in liver, intestine, kidney, and pancreatic islet beta-cells. The apparent molecular mass of the transporter in liver, kidney, and intestine is different, as detected by Western blot analysis of membrane proteins using antipeptide antibodies. However, as assessed by Northern blot analysis and molecular cloning, the same mRNA is expressed in these tissues, indicating that there are tissue-specific posttranslational modifications of the same transporter polypeptide. As determined by immunofluorescence analysis on frozen tissue sections, the liver glucose transporter is present on the sinusoidal membrane of hepatocytes, on the basolateral membrane of fully differentiated absorptive intestine epithelial cells, and on the basolateral membrane of proximal tubule cells of the kidney nephron. This localization is consistent with the involvement of the liver glucose transporter in several key steps of glucose metabolism: glucose uptake and release by the liver and absorption or reabsorption by epithelial cells of the intestine and kidney, respectively.

Separation of human and animal cells by steric field-flow fractionation.

In this work, the feasibility of separating and characterizing cell populations by steric field-flow fractionation (steric FFF) is demonstrated by application to fixed human and avian red cells, fresh blood from several species, and viable HeLa cells. The basis for this work is established by means of a discussion of the role of steric FFF in the broad family of field-flow fractionation techniques. The behavior of steric FFF is then characterized by application to standard polystyrene latex beads and to fixed red blood cells. Studies of these standards and of the other cells noted under various conditions of field strength and flow velocity are used to improve the separation conditions and approach optimization. It is shown that the fixed human and avian red cells can be separated in a time of less than 15 min. In addition, it is shown that HeLa cells maintain their viability after passage through the separation channel.

Sex pheromone components isolated from china corn borer,Ostrinia furnacalis guenée (lepidoptera: Pyralidae), (E)- and (Z)-12-tetradecenyl acetates.

The sex pheromone components from the corn borer spreading widely in China,Ostrinia furnacalis Guenée, have been identified as (E)-and (Z)-12-tetradecenyl acetates (E andZ12-14∶ Ac). The ratio ofE isomer toZ isomer was 53 ∶ 47. Traps containing 1 × 10(-7)-1 × 10(-5) g of these compounds captured more males than did live females or their tip extract (3-6 female equivalents). Tetradecyl acetate (14 ∶ Ac) was also identified in the tip extract. Its quantity was about 1.8 times the sum of the other two isomers. However, including this compound in its natural ratio in pheromone traps resulted in a decrease in trap catches (P< 0.05).