Rapid and dynamic change in hydrogen peroxide (H2O2) levels can serve as an important signal to regulate various biological processes in plants. The change is realized by tilting the balance between its production and scavenging rates, in which membrane-associated NADPH oxidases are known to play a crucial role. Functioning independently from NADPH oxidases, glycolate oxidase (GLO) was recently demonstrated as an alternative source for H2O2 production during both gene-for-gene and non-host resistance in plants. In this study, we show that GLO physically interacts with catalase (CAT) in rice leaves, and that the interaction can be deregulated by salicylic acid (SA). Furthermore, the GLO-mediated H2O2 accumulation is synergistically enhanced by SA. Based on the well-known mechanism of substrate channeling in enzyme complexes, SA-induced H2O2 accumulation likely results from SA-induced GLO-CAT dissociation. In the GLO-CAT complex, GLO-mediated H2O2 production during photorespiration is very high, whereas the affinity of CAT for H2O2 (measured Km ≈ 43 mM) is extraordinarily low. This unique combination can further potentiate the increase in H2O2 when GLO is dissociated from CAT. Taken together, we propose that the physical association-dissociation of GLO and CAT, in response to environmental stress or stimuli, seems to serve as a specific mechanism to modulate H2O2 levels in rice.
Background The objective of the present study was twofold: to demonstrate our experience with unilateral adrenalectomy in the treatment of adrenocorticotropic hormone (ACTH)-independent Cushing syndrome (CS) caused by bilateral adrenocortical hyperplasias, and to evaluate the long-term results as evidenced by the main laboratory and clinical findings. Methods From February 2000 to August 2009, unilateral adrenalectomy was performed on 27 patients with ACTHindependent CS and bilateral adrenocortical hyperplasias, including 14 patients with ACTH-independent macronodular adrenal hyperplasia (AIMAH) and 13 patients with primary pigmented nodular adrenocortical disease (PPNAD). Signs and symptoms of CS, endocrine examinations, and radiographic imaging were evaluated preoperatively and postoperatively.Results At a median follow-up of 69 months (range: 23-120 months) for AIMAH and 47 months (range: 16-113 months) for PPNAD, 25 patients were cured by unilateral adrenalectomy. Serum cortisol level, daily urinary free cortisol (UFC), and plasma ACTH regained the normal range in both AIMAH and PPNAD patients at monthly follow-up visits; the circadian serum cortisol rhythm returned to normal, and a normal responsiveness to overnight low-dose dexamethasone administration (LDDST) became obvious. Both systolic and diastolic blood pressure (BP) levels were significantly reduced: 85 % of patients recovered normal BP levels, and the remaining patients need antihypertensive drugs, but at a reduced dose. No surgery-related morbidity occurred, and there was no sign of further enlargement of the residual adrenal gland after successful unilateral adrenalectomy. One patient with PPNAD and another patient with AIMAH with similar weights and sizes of the bilateral adrenals needed contralateral adrenalectomy. Conclusions Unilateral adrenalectomy may be the suitable treatment for selected patients with AIMAH and PPNAD. It can achieve long-term remission of CS and improve glycemic control and BP values.Wenbin Rui is listed as co-first author.
Background Mechanisms driving the progression of castration-resistant prostate cancer are believed to relate substantially to the tumor microenvironment. However, the cross-talks between tumor epithelial cell, stromal cells, and immune cells are yet to be fully elucidated. The present study aims to determine the role of chemokine and neutrophil derived cytokine paracrine axis in mediating the interaction between tumor cells, stromal myofibroblasts, and neutrophils in the tumor microenvironment of prostate cancer. Methods To identify myofibroblasts and neutrophil derived specific proteins affecting progression of prostate cancer, bioinformatics analyses were firstly performed in independent human prostate cancer gene expression data sets from the GEO data bank. Expression of stromal myofibroblasts secretory chemokine CXCL1 and neutrophil derived cytokine LCN2 was evaluated in prostate tissues via immunohistochemistry assay. We further investigated the effect of CXCL1 and LCN2 on prostate cancer using in vivo and in vitro models, and explored the underlying signal transduction pathways. Results A CXCL1-LCN2 paracrine network was confirmed in prostate cancer tissue samples, which was correlated with the biochemical recurrence of prostate cancer. Of note, CXCL1-LCN2 axis activates Src signaling, triggers the epithelial-mesenchymal transition (EMT), consequently promotes the migration of prostate cancer cells, leading to enhanced tumor metastasis. Conclusions Our findings may provide enhanced insight into the interactions of carcinoma-stromal cells and immune cells linked to prostate cancer progression, wherein CXCL1-LCN2 axis is a key contributor to prostate cancer cells migration. These data indicate tumor microenvironment and Src signaling pathway may be potential therapeutic targets of prostate cancer treatment.
Stearoyl-CoA desaturase 1 (SCD1), the rate-limiting enzymes in the biosynthesis of monounsaturated fatty acids from saturated fatty acids, have been gradually recognized as a potential therapeutic target for various malignancies, particularly in clear-cell renal cell carcinoma (ccRCC). However, the prognostic value of SCD1 in ccRCC is still unknown. The aim of this study is to evaluate the clinical significance of SCD1 expression in patients with ccRCC. SCD1 expression in tumor tissues obtained from 359 patients who underwent nephrectomy for ccRCC are retrospectively assessed. During a median follow-up of 63 months (range: 1–144month), 56 patients in total died before the last follow-up in this study. Survival curves were plotted with the Kaplan–Meier method and compared with the log-rank test. Meanwhile, univariate and multivariate Cox regression models were applied to evaluate the prognostic value of SCD1 expression in overall survival (OS) for ccRCC patients. Moreover, SCD1 was enrolled into a newly built nomogram with factors selected by multivariate analysis, and the calibration was built to evaluate the predictive accuracy of nomogram. High SCD1 expression occurred in 61.6% (221/359) of ccRCC patients, which was significantly associated with age (p = 0.030), TNM stage (p = 0.021), pN stage (p = 0.014), Fuhrman grade (p = 0.014) and tumor sizes (p = 0.040). In multivariate analysis, SCD1 expression was confirmed as an adverse independent prognostic factor for OS. The prognostic accuracy of TNM stage, Fuhrman grade and tumor sizes was significantly increased when SCD1 expression was added. The independent prognostic factors, pT stage, pN stage, Fuhrman grade and tumor sizes, as well as SCD1 expression were integrated to establish a predictive nomogram with high predictive accuracy. Calibration curves revealed optimal consistency between observations and prognosis. In conclusion, high SCD1 expression is an independent prognostic factor for OS in patients with ccRCC. Our data suggest that the expression of SCD1 might guide the clinical decisions for patients with ccRCC.
The purpose of this study was to determine the correlation between human adrenocortical carcinoma (ACC) and the proteins involved in tumor angiogenesis, and to evaluate the angiogenic status of ACC. The expression of heparanase-1 (HPA-1), vascular endothelial growth factor (VEGF), and vascular endothelial growth factor receptor-2 (VEGFR-2) as well as microvessel density (MVD) were measured in a series of tissue samples from 44 human sporadic adrenocortical tumors by immunohistochemistry. These specimens were classified as adenomas (n = 20) and carcinomas (n = 24) according to the histological criteria defined by Weiss. A total of 22 of 24 (91.67%) malignant cases showed positive staining for HPA-1 and 3 of 20 (15%) benign cases showed positive, the difference of HPA-1 expression between ACA and ACC was statistically significant (P < 0.001). Similarly, VEGF staining was seen in 70.83% (17/24) of the malignant cases versus 25% (5/20) of the benign, the difference of VEGF expression among two groups was statistically significant (P = 0.002). VEGFR-2 expressed highly in the ACC group (79.17%, 19/24) and lowly in the benign group (25%, 5/20), the two groups had extremely significant difference (P < 0.001). Malignant cases showed higher MVD compared to benign tumors (84.70 ± 12.44 vs. 21.05 ± 8.07, P < 0.001). HPA-1 and VEGF expression were positively correlated with MVD in all specimens (r_s = 0.812, P = 0.001; r_s = 0.834, P < 0.001). In conclusion, these results suggest that angiogenesis of human ACC maybe mediated by these proteins and they could represent selective targets for the molecularly targeted treatments of ACC.
CB2 expression is functionally related to cellular proliferation, migration, and cell cycle of RCC cells. Our data suggest that CB2 might be a potential therapeutic target for RCC.
Sphingosine kinase 1 (SphK1) is the major source of the bioactive lipid and GPCR agonist sphingosine 1phosphate (S1P). Although alterations in SphK1 expression and activity have been detected in various human malignancies, its potential molecular mechanisms in the development and sunitinib resistance of clear cell renal cell carcinoma (ccRCC) remain obscure. In this study, we aim to evaluate the clinical significance of SphK1 and to explore the therapeutic implications of combination approach for ccRCC patients. We identify upregulation of SphK1 significantly associated with poor prognosis of large cohort of ccRCC patients, which contributing to cell proliferation, colony formation, migration and survival. Suppression of SphK1 activity either by shRNA or pharmacologic inhibitior FTY720 suppresses cell growth in vitro and in vivo. A comprehensive phosphoprotein antibody array reveals that SphK1 overexpression promoted RCC progression by regulating the Akt/mTOR pathway. Moreover, FTY720 administration enhanced tumor growth inhibition effect of sunitinib treatment on RCC cells in vitro and in vivo. Our results unraveled that increased SphK1 kinase activation defines an important mechanism for sunitinib resistance, therefore contributes to tumour development and represents therapeutic targets for ccRCC. ARTICLE HISTORY
Clear cell renal cell carcinoma (ccRCC) is the most common kidney malignancy characterized by a poor prognosis. The treatment efficacy of immune checkpoint inhibitors (ICIs) also varies widely in advanced ccRCC. We aim to construct a robust gene signature to improve the prognostic discrimination and prediction of ICIs for ccRCC patients. In this study, adopting differentially expressed genes from seven ccRCC datasets in GEO (Gene Expression Omnibus), a novel signature (FOXM1&TOP2A) was constructed in TCGA (The Cancer Genome Atlas) database by LASSO and Cox regression. Survival and time-dependent ROC analysis revealed the strong predictive ability of our signature in discovery set, two online validation sets and one tissue microarray (TMA) from our institution. High-risk group based on the signature comprises more high-grade (G3&G4) and advanced pathologic stage (stageIII/IV) tumors and presents hyperactivation of cell cycle process according to the functional analysis. Meanwhile, high-risk tumors demonstrate an immunosuppressive phenotype with more infiltrations of regulatory T cells (Tregs), macrophages and high expressions of genes negatively regulating anti-tumor immunity. Low-risk tumors have an improved response to anti-PD-1 therapy and the predictive ability of our signature is better than other recognized biomarkers in ccRCC. A nomogram containing this signature showed a high predictive accuracy with AUCs of 0.90 and 0.84 at 3 and 5 years. Overall, this robust signature could predict prognosis, evaluate immune microenvironment and response to anti-PD-1 therapy in ccRCC, which is very promising in clinical promotion.
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