IGFBP-rP1 induces p21 expression through a p53-independent pathway, leading to cellular senescence of MCF-7 breast cancer cells

Fructose vs. glucose: modulating stem cell growth and function through sugar supplementation

In multicellular organisms, stem cells are impacted by microenvironmental resources such as nutrient availability and oxygen tension for their survival, growth, and differentiation. However, the accessibility of these resources in the pericellular environment greatly varies from organ to organ. This divergence in resource availability leads to variations in the potency and differentiation potential of stem cells. This study aimed to explore the distinct effects of glucose and fructose, as well as different oxygen tensions, on the growth dynamics, cytokine production, and differentiation of stem cells. We showed that replacing glucose with fructose subjected stem cells to stress, resulting in increased Hif1α expression and stability, which in turn led to a reduction in cell proliferation, and alterations in cytokine production. However, fructose failed to induce differentiation of human mesenchymal stem cells (hMSCs) as well as mouse fibroblasts into mature adipocytes compared to glucose, despite the upregulation of key markers of adipogenesis, including C/EBPβ, and PPARγ. Conversely, we showed that fructose induced undifferentiated mouse fibroblasts to release cytokines associated with senescence, including IL1α1, IL6, IL8, MCP1, and TNF1α, suggesting that these cells were undergoing lipolysis. Taken together, our results suggest that altering the culture conditions through changes in hexose levels and oxygen tension places considerable stress on stem cells. Additional research is required to further characterize the mechanisms governing stem cell response to their microenvironments.

AS1041, a novel derivative of marine natural compound Aspergiolide A, induces senescence of leukemia cells via oxidative stress-induced DNA damage and BCR-ABL degradation

Chronic myelogenous leukemia (CML) is characterized by the constitutive activation of BCR-ABL tyrosine kinase. Imatinib was approved for CML therapy, however, BCR-ABL-dependent drug resistance, especially BCR-ABL-T315I mutation, restricts its clinical application. In this study, we reported anthraquinone lactone AS1041, a synthesized derivative of marine natural compound Aspergiolide A, showed anti-leukemia effect in vitro and in vivo by promoting cell senescence. Mechanistic study revealed the pro-senescence effect of AS1041 was dependent on oxidative stress-induced DNA damage, and the resultant activation of P53/P21 and P16INK4a/Rb. Also, AS1041 promoted ubiquitin proteasome system (UPS)-mediated BCR-ABL degradation, which also contributed to AS1041-induced senescence. In vivo, AS1041-induced senescence promoted tumor growth inhibition. In summary, the in vitro and in vivo antitumor effect of AS1041 suggests it can serve as a pro-senescence agent for alternative antileukemia therapy and imatinib-resistant cancer therapy by enhancing cellular oxidative stress and BCR-ABL degradation.

New biomarkers in acute kidney injury

Acute kidney injury (AKI) is a commonly encountered clinical syndrome. Although it often complicates community acquired illness, it is more common in hospitalized patients, particularly those who are critically ill or who have undergone major surgery. Approximately 20% of hospitalized adult patients develop an AKI during their hospital care, and this rises to nearly 60% in the critically ill, depending on the population being considered. In general, AKI is more common in older adults, in those with preexisting chronic kidney disease and in those with known risk factors for AKI (including diabetes and hypertension). The development of AKI is associated with an increase in both mortality and morbidity, including the development of post-AKI chronic kidney disease. Currently, AKI is defined by a rise in serum creatinine from either a known or derived baseline value and/or oliguria or anuria. However, clinicians may fail to recognize the initial development of AKI because of a delay in the rise of serum creatinine or because of inaccurate urine output monitoring. This, in turn, delays any putative measures to treat AKI or to limit its degree. Consequently, efforts have focused on new biomarkers associated with AKI that may allow early recognition of this syndrome with the intent that this will translate into improved patient outcomes. Here we outline current biomarkers associated with AKI and explore their potential in aiding diagnosis, understanding the pathophysiology and directing therapy.

Effects and potential mechanisms of IGF1/IGF1R in the liver fibrosis: A review

Liver fibrosis is a wound-healing response due to persistent liver damage and it may progress to cirrhosis and even liver cancer if no intervention is given. In the current cognition, liver fibrosis is reversible. So, it is of great significance to explore the related gene targets or biomarker for anti-fibrosis of liver. Insulin like growth factor 1 (IGF1) and IGF1 receptor (IGF1R) are mainly expressed in the liver tissues and play critical roles in the liver function. The present review summarized the role of IGF1/IGF1R and its signaling system in liver fibrosis and illustrated the potential mechanisms including DNA damage repair, cell senescence, lipid metabolism and oxidative stress that may be involved in this process according to the studies on the fibrosis of liver or other organs. In particular, the roles of IGF1 and IGF1R in DNA damage repair were elaborated, including membrane-localized and nucleus-localized IGF1R. In addition, for each of the potential mechanism in anti-fibrosis of liver, the signaling pathways of the IGF1/IGF1R mediated and the cell species in liver acted by IGF1 and IGF1R under different conditions were included. The data in this review will support for the study about the effect of IGF1/IGF1R on liver fibrosis induced by various factors, meanwhile, provide a basis for the study of liver fibrosis to focus on the communications between the different kinds of liver cells.

Predictive value of urinary cell cycle arrest biomarkers for all cause-acute kidney injury: a meta-analysis

The cell cycle arrest markers tissue inhibitor metalloproteinases-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) have been identified as potential biomarkers of acute kidney injury (AKI) in critically ill adults in intensive care units and cardiac surgery-associated AKI (CSA-AKI). However, the clinical impact on all-cause AKI remains unclear. Here, we report a meta-analysis performed to evaluate the predictive value of this biomarker for all-cause AKI. The PubMed, Cochrane, and EMBASE databases were systematically searched up to April 1, 2022. We used the Quality Assessment Tool for Diagnosis Accuracy Studies (QUADAS-2) to assess the quality. We extracted useful information from these studies and calculated the sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC). Twenty studies with 3625 patients were included in the meta-analysis. The estimated sensitivity of urinary [TIMP-2] × [IGFBP7] in the diagnosis of all-cause AKI was 0.79 (95% CI 0.72, 0.84), and the specificity was 0.70 (95% CI 0.62, 0.76). The value of urine [TIMP-2] × [IGFBP7] in the early diagnosis of AKI was assessed using a random effects model. The pooled positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were 2.6 (95% CI 2.1, 3.3), 0.31 (95% CI 0.23, 0.40), and 8 (95% CI 6, 13), respectively. The AUROC was 0.81 (95% CI 0.78-0.84). No significant publication bias was observed in eligible studies. Subgroup analysis indicated that the diagnostic value was related to the severity of AKI, time measurement, and clinical setting. This study shows that urinary [TIMP-2] × [IGFBP7] is a reliable effective predictive test for all cause-AKI. However, whether and how urinary [TIMP-2] × [IGFBP7] can be used in clinical diagnosis still requires further research and clinical trials.

WNT/beta-catenin signalling interrupts a senescence-induction cascade in human mesenchymal stem cells that restricts their expansion

Senescence, the irreversible cell cycle arrest of damaged cells, is accompanied by a deleterious pro-inflammatory senescence-associated secretory phenotype (SASP). Senescence and the SASP are major factors in aging, cancer, and degenerative diseases, and interfere with the expansion of adult cells in vitro, yet little is known about how to counteract their induction and deleterious effects. Paracrine signals are increasingly recognized as important senescence triggers and understanding their regulation and mode of action may provide novel opportunities to reduce senescence-induced inflammation and improve cell-based therapies. Here, we show that the signalling protein WNT3A counteracts the induction of paracrine senescence in cultured human adult mesenchymal stem cells (MSCs). We find that entry into senescence in a small subpopulation of MSCs triggers a secretome that causes a feed-forward signalling cascade that with increasing speed induces healthy cells into senescence. WNT signals interrupt this cascade by repressing cytokines that mediate this induction of senescence. Inhibition of those mediators by interference with NF-κB or interleukin 6 signalling reduced paracrine senescence in absence of WNT3A and promoted the expansion of MSCs. Our work reveals how WNT signals can antagonize senescence and has relevance not only for expansion of adult cells but can also provide new insights into senescence-associated inflammatory and degenerative diseases.

Plasma Endogenous Sulfur Dioxide: A Novel Biomarker to Predict Acute Kidney Injury in Critically Ill Patients

Purpose

Sulfur dioxide (SO₂) is a novel gaseous signaling molecule that plays an important role in inflammation, which contributes the pathogenesis of acute kidney injury (AKI). The aim of this study was to explore the predictive value of plasma SO₂ for AKI in high-risk patients.

Patients and Methods

A prospective cohort of 167 patients who underwent major noncardiac surgery was enrolled in the study. Plasma SO₂, urine neutrophil gelatinase-associated lipocalin (NGAL), tissue inhibitor of metalloproteinase-2 (TIMP-2), and insulin-like growth factor-binding protein 7 (IGFBP7) levels were detected immediately after the operation. The primary endpoint was new-onset AKI within 72 h after admission. The ability of biomarkers including SO₂ and a clinical risk model to predict AKI was compared by receiver operator characteristic (ROC) curve analysis and decision curve analysis (DCA), additional contributions were evaluated by integrated discrimination improvement (IDI) and net reclassification improvement (NRI) analyses.

Results

A total of 61 (36.5%) patients developed AKI within 72 h of surgery. Compared to NGAL and [TIMP-2]·[IGFBP7], SO₂ showed better predictive ability for new-onset AKI with an area under the ROC curve of 0.771 (95% confidence interval: 0.700–0.832, p<0.001). The improvement in predictive value by including SO₂ in the clinical risk model was supported by NRI (0.28; P=0.04) and IDI (0.15; P<0.001) analyses. The net benefit of the combination of SO₂ and clinical variables was the max in DCA.

Conclusion

Plasma SO₂ shows a useful value for predicting new-onset AKI, and improved AKI prediction based on clinical variables, which can guide the implementation of preventive measures for high-risk patients.

Chromatin-Directed Proteomics Identifies ZNF84 as a p53-Independent Regulator of p21 in Genotoxic Stress Response

Simple Summary

Chemotherapy is a commonly applied anticancer treatment, however therapy-induced senescent growth arrest has been associated with aggressive disease recurrence. The p21 protein, encoded by CDKN1A, plays a vital role in the induction of senescence. Its transcriptional control by p53 is well-established. However, in many cancers where TP53 is mutated, p21 expression must be triggered by p53-independent mechanisms. We here used a chromatin-directed proteomic approach and identified ZNF84 as a regulator of CDKN1A gene expression in various p53-deficient cell lines. Knock-down of ZNF84, an as-yet un-characterized protein, inhibited p21 gene and protein expression in response to doxorubicin and facilitated senescence bypass. Intriguingly, ZNF84 depletion diminished genotoxic burden evoked by doxorubicin. Clinical data association studies indicated the relevance of ZNF84 expression for patient survival. Collectively, we identified ZNF84 as a critical regulator of senescence-proliferation outcome of chemotherapy, opening possibilities for its targeting in novel anti-cancer therapies of p53-mutated tumours.

Abstract

The p21^WAF1/Cip1 protein, encoded by CDKN1A, plays a vital role in senescence, and its transcriptional control by the tumour suppressor p53 is well-established. However, p21 can also be regulated in a p53-independent manner, by mechanisms that still remain less understood. We aimed to expand the knowledge about p53-independent senescence by looking for novel players involved in CDKN1A regulation. We used a chromatin-directed proteomic approach and identified ZNF84 as a novel regulator of p21 in various p53-deficient cell lines treated with cytostatic dose of doxorubicin. Knock-down of ZNF84, an as-yet un-characterized protein, inhibited p21 gene and protein expression in response to doxorubicin, it attenuated senescence and was associated with enhanced proliferation, indicating that ZNF84-deficiency can favor senescence bypass. ZNF84 deficiency was also associated with transcriptomic changes in genes governing various cancer-relevant processes e.g., mitosis. In cells with ZNF84 knock-down we discovered significantly lower level of H2AX Ser139 phosphorylation (γH2AX), which is triggered by DNA double strand breaks. Intriguingly, we observed a reverse correlation between the level of ZNF84 expression and survival rate of colon cancer patients. In conclusion, ZNF84, whose function was previously not recognized, was identified here as a critical p53-independent regulator of senescence, opening possibilities for its targeting in novel therapies of p53-null cancers.

Oxidatively Modified LDL Suppresses Lymphangiogenesis via CD36 Signaling

Arterial accumulation of plasma-derived LDL and its subsequent oxidation contributes to atherosclerosis. Lymphatic vessel (LV)-mediated removal of arterial cholesterol has been shown to reduce atherosclerotic lesion formation. However, the precise mechanisms that regulate LV density and function in atherosclerotic vessels remain to be identified. The aim of this study was to investigate the role of native LDL (nLDL) and oxidized LDL (oxLDL) in modulating lymphangiogenesis and underlying molecular mechanisms. Western blotting and immunostaining experiments demonstrated increased oxLDL expression in human atherosclerotic arteries. Furthermore, elevated oxLDL levels were detected in the adventitial layer, where LV are primarily present. Treatment of human lymphatic endothelial cells (LEC) with oxLDL inhibited in vitro tube formation, while nLDL stimulated it. Similar results were observed with Matrigel plug assay in vivo. CD36 deletion in mice and its siRNA-mediated knockdown in LEC prevented oxLDL-induced inhibition of lymphangiogenesis. In addition, oxLDL via CD36 receptor suppressed cell cycle, downregulated AKT and eNOS expression, and increased levels of p27 in LEC. Collectively, these results indicate that oxLDL inhibits lymphangiogenesis via CD36-mediated regulation of AKT/eNOS pathway and cell cycle. These findings suggest that therapeutic blockade of LEC CD36 may promote arterial lymphangiogenesis, leading to increased cholesterol removal from the arterial wall and reduced atherosclerosis.

Current concepts and advances in biomarkers of acute kidney injury

Despite advancements in standardizing the criteria for acute kidney injury (AKI), its definition remains based on changes in serum creatinine and urinary output that do not specifically represent tubular function or injury and that have significant limitations in the acute hospital setting. Much effort in nephrology has centered on identifying biomarkers of AKI to address these limitations. This review summarizes recent advances in our knowledge of biomarkers involved in pathophysiological processes during AKI and describes their potential clinical implications. Blood and urine biomarkers are released via various mechanisms during renal tubular injury. Urinary kidney injury molecule-1 (KIM-1), liver-type fatty acid binding protein (L-FABP), insulin-like growth factor-binding protein-7 (IGFBP-7), and tissue inhibitor of metalloprotease-2 (TIMP-2) are released from the proximal tubule while uromodulin (UMOD) is secreted from the loop of Henle and neutrophil gelatinase-associated lipocalin (NGAL) is released from the distal tubule. These biomarkers could therefore be used to localize specific segments of injured tubules. Biomarkers also have diverse roles in pathophysiological processes in AKI, including inflammation, repair, and fibrosis. Current evidence suggests that these biomarkers could be used to predict the transition to chronic kidney disease (CKD), decrease discard of AKI kidneys, differentiate between kidney dysfunction and injury, guide AKI management, and improve diagnosis of diseases such as acute interstitial nephritis (AIN). They could differentiate between disease phenotypes, facilitate the inclusion of a homogenous patient population in future trials of AKI, and shed light on therapeutic pathways to prevent the transition from AKI to CKD. However, a major limitation of current biomarker research in AKI is the lack of tissue correlation. The Kidney Precision Medicine Project, a large-scale national effort, is currently underway to construct a kidney tissue atlas and expand the use of biomarkers to assess nephron health. Numerous biomarkers are involved in distinct pathophysiological processes after kidney injury and have demonstrated potential to improve diagnosis and risk stratification as well as provide a prognosis for patients with AKI. Some biomarkers are ready for use in clinical trials of AKI and could guide management in various clinical settings. Further investigation of these biomarkers will provide insight that can be applied to develop novel therapeutic agents for AKI.

Pcresol and Indoxyl Sulfate Impair Osteogenic Differentiation by Triggering Mesenchymal Stem Cell Senescence

Chronic kidney disease (CKD) patients obtained high levels of uremic toxins progressively develop several complications including bone fractures. Protein-bound uremic toxins especially p-cresol and indoxyl sulfate are hardly eliminated due to their high molecular weight. Thus, the abnormality of bone in CKD patient could be potentially resulted from the accumulation of uremic toxins. To determine whether protein-bound uremic toxins have an impact on osteogenesis, mesenchymal stem cells were treated with either p-cresol or indoxyl sulfate under in vitro osteogenic differentiation. The effects of uremic toxins on MSC-osteoblastic differentiation were investigated by evaluation of bone phenotype. The results demonstrated that p-cresol and indoxyl sulfate down-regulated the transcriptional level of collagen type I, deceased alkaline phosphatase activity, and impaired mineralization of MSC-osteoblastic cells. Furthermore, p-cresol and indoxyl sulfate gradually increased senescence-associated beta-galactosidase positive cells while upregulated the expression of p21 which participate in senescent process. Our findings clearly revealed that the presence of uremic toxins dose-dependently influenced a gradual deterioration of osteogenesis. The effects partially mediate through the activation of senescence-associated gene lead to the impairment of osteogenesis. Therefore, the management of cellular senescence triggered by uremic toxins could be considered as an alternative therapeutic approach to prevent bone abnormality in CKD patients.

Insulin Growth Factor Binding Protein 7 (IGFBP7)-Related Cancer and IGFBP3 and IGFBP7 Crosstalk

The insulin/insulin-like growth factors (IGFs) have crucial tasks in the growth, differentiation, and proliferation of healthy and pernicious cells. They are involved in coordinated complexes, including receptors, ligands, binding proteins, and proteases. However, the systems can become dysregulated in tumorigenesis. Insulin-like growth factor-binding protein 7 (IGFBP7) is a protein belonging to the IGFBP superfamily (also termed GFBP-related proteins). Numerous studies have provided evidence that IGFBP3 and IGFBP7 are involved in a variety of cancers, including hepatocellular carcinoma (HCC), breast cancer, gastroesophageal cancer, colon cancer, prostate cancer, among many others. Still, very few suggest an interaction between these two molecules. In studying several cancer types in our laboratories, we found that both proteins share some crucial signaling pathways. The objective of this review is to present a comprehensive overview of the relationship between IGFBP7 and cancer, as well as highlighting IGFBP3 crosstalk with IGFBP7 reported in recent studies.

Alterations in genetic pathways following radiotherapy for head and neck cancer

BACKGROUND

Radiotherapy (RT) is an integral component in the treatment of head and neck cancer (HNC).We hypothesized there would be alterations in gene-expression and pathway activity in HNC samples obtained in recurrent HNC that were previously treated with RT, when compared to RT-naïve disease.

METHODS

Patient data was abstracted from a prospectively maintained database. Linear-microarray analysis and supervised gene-set enrichment-analysis were employed to compare RT-naive and recurrent disease after prior-RT.

RESULTS

A total of 157 patients were analyzed, 96 (61%) were RT-naive and 61 (39%) had RT.After radiation, there was upregulation of genes associated with angiogenesis, protein-translation-machinery, cell-cycle regulation, and growth factors, and downregulation associated with Myc activity, and hypoxic response (all P < .001).Previously irradiated HNC was associated with downregulation in 19/42 genes in the Wnt/B-catenin-pathway (P = .045)and 119/199 genes involved in the MYC target pathway (P = .024).

CONCLUSION

Patients with recurrences salvaged surgically post-RT had significant alterations in gene-expression and in Wnt/B-catenin and MYC-target pathways. These pathways may represent potential targets to prevent development of resistance to RT.

Urinary TIMP-2 Predicts the Presence and Duration of Delayed Graft Function in Donation After Circulatory Death Kidney Transplant Recipients

BACKGROUND

Urinary tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor binding protein-7 (IGFBP7) have been validated as biomarkers for acute kidney injury. We investigated the performance of both markers in predicting the occurrence and duration of functionally defined delayed graft function (fDGF) in donation after circulatory death (DCD) kidney transplant recipients.

METHODS

Urine samples of 74 DCD recipients were analyzed. TIMP-2 and IGFBP7 were measured with ELISA on postoperative days 1 to 7, day 10, week 6, and month 6, and values were corrected for osmolality (mOsm). Immunosuppression consisted of anti-CD25 antibody induction and triple maintenance therapy (steroids, mycophenolate mofetil, and calcineurin inhibitor). Statistical analysis included receiver operating characteristic curves and multivariate logistic regression.

RESULTS

Fifty-one (69%) renal transplant recipients had fDGF, of which 14 experienced prolonged fDGF (≥21 days). TIMP-2/mOsm on day-1 and day-10 adequately identified patients with fDGF (area under the curve [AUC], 0.91) and prolonged fDGF (AUC, 0.80), respectively, whereas IGFBP7/mOsm did not (AUC, 0.63 and 0.60). Multivariate analysis on day 1 identified 24-hour urinary creatinine excretion and TIMP-2/mOsm as significant predictors of fDGF (AUC, 0.90, 95% confidence interval, 0.80-0.98). The best predictors of prolonged fDGF on day 10 were 24-hour urinary creatinine excretion, TIMP-2/mOsm, and total warm ischemia time with an AUC of 0.85 (95% confidence interval, 0.72-0.95). Consecutive TIMP-2/mOsm values showed a decrease in TIMP-2/mOsm before an increase in estimated glomerular filtration rate, enabling us to monitor fDGF and predict resolution of fDGF.

CONCLUSIONS

Urinary TIMP-2, but not IGFBP7, is a promising biomarker to predict the occurrence and duration of fDGF in DCD kidney transplant recipients.

Rotundic acid induces Cas3-MCF-7 cell apoptosis through the p53 pathway

In the present study, the functions and mechanisms of rotundic acid (RA) underlying its induction of apoptosis in caspase-3-transfected MCF-7 human breast cancer cells (Cas3-MCF-7 cells) were investigated. RA induced apoptosis in Cas3-MCF-7 cells more efficiently compared with that in MCF-7 cells transfected with control plasmid. The results from an MTT assay demonstrated that RA effectively inhibited Cas3-MCF-7 cell viability in a dose-dependent manner and induced cell apoptosis via caspase-3 activity within 12 to 48 h. Western blotting and fluorescence-activated cell sorting demonstrated that RA initiated Cas3-MCF-7 cell apoptosis via p53 activation. The silencing of the p53 gene in the Cas3-MCF-7 cell line led to decreased RA-induced Cas3-MCF-7 cell caspase-3 activity and cell apoptosis. Collectively, the results of the present study indicate that caspase-3 serves a critical function in rotundic acid-induced apoptosis, and suggest that caspase-3 deficiency may contribute to the chemotherapy-resistance of breast cancer. Reconstitution of caspase-3 sensitizes MCF-7 breast cancer cells to chemotherapy. RA has the potential for development as a novel drug combined with reconstitution of caspase-3 gene therapy for the treatment of human breast cancer with caspase-3 deficiency.

Rotundic acid enhances the impact of radiological toxicity on MCF-7 cells through the ATM/p53 pathway

Although radiation therapy is a powerful anticancer modality, radiation- induced stress response and gene expression with adaptive resistance may severely compromise the effectiveness of radiation. The function of rotundic acid (RA) on inducing apoptosis in the human breast cancer cell line MCF-7 has been investigated in a previous study. In the present study, the combined effect of chemotherapy and radiotherapy on reducing side effects was examined. The results of an MTT assay revealed that radiation (0.5, 2 and 10 Gy) effectively inhibit MCF-7 cell viability in a dose-dependent manner, consistent with the effects of RA (2, 5 and 12.5 µM). Interestingly, a lower dose of radiation (1 Gy) combined with RA (5 µM) exhibited a greater inhibition efficiency compared with a high dose of radiation alone. Flow cytometry revealed that radiation combined with RA induced the apoptosis of MCF-7 cells. Using western blotting, it was demonstrated that radiation induced the expression of ataxia-telangiectasia mutated (ATM) and p53 protein, and that RA enhanced this effect. On examining the potential underlying mechanism, it was revealed that radiation and RA combined induce Bcl-2-associated X protein expression and cell apoptosis in MCF-7 cells. An ATM inhibitor was able to restore the effect of radiation and RA on inducing MCF-7 cell apoptosis. These results suggest that the ATM/p53 pathway directly participates in radiation and RA-induced apoptosis in MCF-7 cells. RA has the potential for development as a novel drug for the treatment of human breast cancer combined with radiation therapy, given that the combined side effects are reduced.

Anticancer effects of liriodenine on the cell growth and apoptosis of human breast cancer MCF-7 cells through the upregulation of p53 expression

Liriodenine has wide pharmacological functions in phytochemistry, pharmacology and antitumor activities. The anticancer effects of liriodenine on the cell growth and apoptosis of human breast cancer MCF-7 cells, and the underlying mechanisms, are yet to be elucidated. Therefore, the present study investigated the anticancer effects of liriodenine on the cell growth and apoptosis of human breast cancer MCF-7 cells. We used MTT assay to measure cell growth, and flow cytometer and DAPI staining was used to analyze cell apoptosis. Then, Western blot analysis was executed to measure B-cell lymphoma-2 protein (Bcl-2), cyclin D1, vascular endothelial growth factor (VEGF), and p53 protein expression. The effect of liriodenine induced significant apoptosis and suppression of cell growth of the MCF-7 cells. Furthermore, the potential mechanism underlying its antitumor effect on MCF-7 cells may result from activation of caspase-3 activity, Bcl-2, cyclin D1 and VEGF, and promotion of p53 protein expression in MCF-7 cells. Therefore, the present results indicated that the anticancer effects of liriodenine suppress cell growth and induce the apoptosis of human breast cancer MCF-7 cells through inhibition of Bcl-2, cyclin D1 and VEGF expression, and upregulation of p53 expression. Therefore, liriodenine may be a potential therapy for the treatment of human breast cancer.

Urinary Tissue Inhibitor of Metalloproteinase-2 and Insulin-Like Growth Factor-Binding Protein 7 for Risk Stratification of Acute Kidney Injury in Patients With Sepsis

Supplemental Digital Content is available in the text.

Objectives:

To examine the performance of the urinary biomarker panel tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 in patients with sepsis at ICU admission. To investigate the effect of nonrenal organ dysfunction on tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 in this population.

Method:

In this ancillary analysis, we included patients with sepsis who were enrolled in either of two trials including 39 ICUs across Europe and North America. The primary endpoint was moderate-severe acute kidney injury (equivalent to Kidney Disease Improving Global Outcome stage 2–3) within 12 hours of enrollment. We assessed biomarker performance by calculating the area under the receiver operating characteristic curve, sensitivity, specificity, and negative and positive predictive values at three cutoffs: 0.3, 1.0, and 2.0 (ng/mL)²/1,000. We also calculated nonrenal Sequential Organ Failure Assessment scores for each patient on enrollment and compared tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 results in patients with and without acute kidney injury and across nonrenal Sequential Organ Failure Assessment scores. Finally, we constructed a clinical model for acute kidney injury in this population and compared the performance of the model with and without tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7.

Results:

We included 232 patients in the analysis and 40 (17%) developed acute kidney injury. We observed significantly higher urine tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 in patients with acute kidney injury than without acute kidney injury in both patients with low and high nonrenal Sequential Organ Failure Assessment scores (p < 0.001). The area under the receiver operating characteristic curve (95% CI) of tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 was 0.84 (0.73–0.92) and 0.85 (0.76–0.94), in low and high nonrenal Sequential Organ Failure Assessment score subgroups. Performance of the tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 test was not modified by nonrenal Sequential Organ Failure Assessment (p = 0.70). In multivariate analysis, the addition of tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 significantly improved the performance of a clinical model for predicting acute kidney injury (p = 0.015).

Conclusion:

Urinary tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 accurately predicts acute kidney injury in septic patients with or without other organ failures.

Redox control of senescence and age-related disease

The signaling networks that drive the aging process, associated functional deterioration, and pathologies has captured the scientific community's attention for decades. While many theories exist to explain the aging process, the production of reactive oxygen species (ROS) provides a signaling link between engagement of cellular senescence and several age-associated pathologies. Cellular senescence has evolved to restrict tumor progression but the accompanying senescence-associated secretory phenotype (SASP) promotes pathogenic pathways. Here, we review known biological theories of aging and how ROS mechanistically control senescence and the aging process. We also describe the redox-regulated signaling networks controlling the SASP and its important role in driving age-related diseases. Finally, we discuss progress in designing therapeutic strategies that manipulate the cellular redox environment to restrict age-associated pathology.

Diagnostic value of urinary tissue inhibitor of metalloproteinase-2 and insulin-like growth factor binding protein 7 for acute kidney injury: a meta-analysis

BACKGROUND

Tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7), inducers of G1 cell cycle arrest, are two recently discovered good biomarkers for early diagnosis of acute kidney injury (AKI). To obtain a more robust performance measurement, the present meta-analysis was performed, pooling existing studies.

METHODS

Literature in the MEDLINE (via PubMed), Ovid, Embase, and Cochrane Library databases was systematically searched from inception to 12 October 2016. Studies that met the set inclusion and exclusion criteria were identified by two independent investigators. The diagnostic value of urinary [TIMP-2] × [IGFBP7] for AKI was evaluated by pooled sensitivity, specificity, likelihood ratio (LR), diagnostic odds ratio (DOR), and summary receiver operating characteristic (SROC) curve analyses. The causes of heterogeneity were explored by sensitivity and subgroup analyses.

RESULTS

A total of nine published and eligible studies assessing 1886 cases were included in this meta-analysis. Early diagnostic value of urinary [TIMP-2] × [IGFBP7] for AKI was assessed using a random-effects model. Pooled sensitivity and specificity with corresponding 95% CIs were 0.83 (95% CI 0.79-0.87, heterogeneity I 2  = 68.8%) and 0.55 (95% CI 0.52-0.57, I 2  = 92.9%), respectively. Pooled positive LR, negative LR, and DOR were 2.37 (95% CI 1.87-2.99, I 2  = 82.6%), 0.30 (95% CI 0.21-0.41, I 2  = 43.4%), and 9.92 (95% CI 6.09-16.18, I 2  = 38.5%), respectively. The AUC estimated by SROC was 0.846 (SE 0.027) with a Q* value of 0.777 (SE 0.026). Sensitivity analysis indicated that one study significantly affected the stability of pooled results. Subgroup analysis showed that population setting and AKI threshold were the key factors causing heterogeneity in pooled sensitivity and specificity.

CONCLUSIONS

On the basis of recent evidence, urinary [TIMP-2] × [IGFBP7] is an effective predictive factor of AKI.

TRIAL REGISTRATION

PROSPERO registration number: CRD42016051186 . Registered on 10 November 2016.

Biomarkers in acute kidney injury - pathophysiological basis and clinical performance

Various biomarkers of acute kidney injury (AKI) have been discovered and characterized in the recent past. These molecules can be detected in urine or blood and signify structural damage to the kidney. Clinically, they are proposed as adjunct diagnostics to serum creatinine and urinary output to improve the early detection, differential diagnosis and prognostic assessment of AKI. The most obvious requirements for a biomarker include its reflection of the underlying pathophysiology of the disease. Hence, a biomarker of AKI should derive from the injured kidney and reflect a molecular process intimately connected with tissue injury. Here, we provide an overview of the basic pathophysiology, the cellular sources and the clinical performance of the most important currently proposed biomarkers of AKI: neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), liver-type fatty acid-binding protein (L-FABP), interleukin-18 (IL-18), insulin-like growth factor-binding protein 7 (IGFBP7), tissue inhibitor of metalloproteinase 2 (TIMP-2) and calprotectin (S100A8/9). We also acknowledge each biomarker's advantages and disadvantages as well as important knowledge gaps and perspectives for future studies.

Comparison of telomere length and insulin-like growth factor-binding protein 7 promoter methylation between breast cancer tissues and adjacent normal tissues in Turkish women

BACKGROUND

Both insulin-like growth factor-binding protein 7 (IGFBP7) and telomere length (TL) are associated with proliferation and senescence of human breast cancer. This study assessed the clinical significance of both TL and IGFBP7 methylation status in breast cancer tissues compared with adjacent normal tissues. We also investigated whether IGFBP7 methylation status could be affecting TL.

METHODS

Telomere length was measured by quantitative PCR to compare tumors with their adjacent normal tissues. The IGFBP7 promoter methylation status was evaluated by methylation-specific PCR and its expression levels were determined by western blotting.

RESULTS

Telomeres were shorter in tumor tissues compared to controls (P<.0001). The mean TL was higher in breast cancer with invasive ductal carcinoma (IDC; n=72; P=.014) compared with other histological type (n=29), and TL in IDC with HER2 negative (n=53; P=.017) was higher than TL in IDC with HER2 positive (n=19). However, telomeres were shortened in advanced stages and growing tumors. IGFBP7 methylation was observed in 90% of tumor tissues and 59% of controls (P=.0002). Its frequency was significantly higher in IDC compared with invasive mixed carcinoma (IMC; P=.002) and it was not correlated either with protein expression or the other clinicopathological parameters.

CONCLUSION

These results suggest that IGFBP7 promoter methylation and shorter TL in tumor compared with adjacent tissues may be predictive biomarkers for breast cancer. Telomere maintenance may be indicative of IDC and IDC with HER2 (-) of breast cancer. Further studies with larger number of cases are necessary to verify this association.

Remote Ischemic Preconditioning in the PICU: A Simple Concept With a Complex Past

OBJECTIVE

In this study, we will review the most recently proposed mechanisms for remote ischemic preconditioning and summarize the past 10 years of clinical studies, as well as potential reasons for why, despite over 20 years of research on remote ischemic preconditioning, it is not routinely used in the pediatric critical care patient. In addition, future directions for remote ischemic preconditioning research will be discussed.

DATA SOURCES

We searched the PubMed database for relevant literature.

STUDY SELECTION AND DATA EXTRACTION

In PubMed, the search terms "ischemic preconditioning" and "remote preconditioning" were used. Randomized controlled trials published from 2006 until the present time that used a blood pressure cuff to induce remote ischemic preconditioning were included. We also reviewed the reference lists of the articles found in the PubMed search and included those thought to contribute to the objectives. All studies pertaining to remote ischemic preconditioning that included pediatric patients were reviewed.

DATA SYNTHESIS AND CONCLUSIONS

Differences in study outcomes in the effect of remote ischemic preconditioning on organ protection have been reported and may have played a large role in limiting the translation of findings into routine clinical practice. Ongoing efforts to protocolize the remote ischemic preconditioning technique in large multicenter trials with clearly delineated patient risk groups, including the use of biomarkers for enrichment, may help to ultimately determine if this procedure can be safely and effectively used for critically ill children.

The cell cycle biomarkers: promising research, but do not oversell them

This review focuses on the most recent scientific and clinical information on the development and clinical applicability of the cell cycle biomarkers TIMP-2 and IGFBP-7 in the diagnosis and prognosis of patients at risk for and suffering from acute kidney injury (AKI). A number of evaluation studies have demonstrated that compared with existing biomarkers, urinary excretion of the product of both biomarkers, [TIMP-2]•[IGFBP-7], improved diagnostic performance in assessing the risk for AKI, predicting the need for renal replacement therapy, AKI-related complications and short- and long-term prognoses. The reference intervals for these biomarkers, measured by the recently approved NephroCheck test, have been determined in apparently healthy adults and those with stable chronic morbid conditions without AKI. This review recognizes that the combination of these two cell cycle arrest markers for the early detection of AKI is promising but concludes that its clinical impact is still unproved. Clinicians should understand the utility and limitations of this test before deciding whether to make it available at their institution.

Clinical Use of the Urine Biomarker [TIMP-2] × [IGFBP7] for Acute Kidney Injury Risk Assessment

Acute kidney injury (AKI) is a serious complication, commonly occurring in the critically ill population, with devastating short- and long-term consequences. Despite standardization of the definition and staging of AKI, early recognition remains challenging given that serum creatinine level is a marker, albeit imperfect, of kidney function and not kidney injury. Furthermore, the delay in increase in serum creatinine level after loss of glomerular filtration also prevents timely detection of decreased kidney function in patients with AKI. During the past decade, numerous clinical investigations have evaluated the utility of several biomarkers in the early diagnosis and risk stratification of AKI. In 2014, the US Food and Drug Administration approved the marketing of a test based on the combination of urine concentrations of tissue inhibitor of metalloproteinase 2 and insulin-like growth factor binding protein 7 ([TIMP-2] × [IGFBP7]) to determine whether certain critically ill patients are at risk for developing moderate to severe AKI. The optimal role of this biomarker in the diagnosis, management, and prognosis of AKI in different clinical settings requires further clarification. In this perspective, we summarize the biological actions of these 2 cell-cycle arrest biomarkers and present important considerations regarding the clinical application, interpretation, and limitations of this novel test for the early detection of AKI.

Modification of cytokine-induced killer cells with chimeric antigen receptors (CARs) enhances antitumor immunity to epidermal growth factor receptor (EGFR)-positive malignancies

Epidermal growth factor receptor (EGFR, ErbB1, Her-1) is a cell surface molecule overexpressing in a variety of human malignancies and, thus, is an excellent target for immunotherapy. Immunotherapy targeting EGFR-overexpressing malignancies using genetically modified immune effector cells is a novel and promising approach. In the present study, we have developed an adoptive cellular immunotherapy strategy based on the chimeric antigen receptor (CAR)-modified cytokine-induced killer (CAR-CIK) cells specific for the tumor cells expressing EGFR. To generate CAR-CIK cells, a lentiviral vector coding the EGFR-specific CAR was constructed and transduced into the CIK cells. The CAR-CIK cells showed significantly enhanced cytotoxicity and increased production of cytokines IFN-γ and IL-2 when co-cultured with EGFR-positive cancer cells. In tumor xenografts, adoptive immunotherapy of CAR-CIK cells could inhibit tumor growth and prolong the survival of EGFR-overexpressing human tumor xenografts. Moreover, tumor growth inhibition and prolonged survival in mice with EGFR(+) human cancer were associated with the increased persistence of CAR-CIK cells in vivo. Our study indicates that modification with EGFR-specific CAR strongly enhances the antitumor activity of the CIK cells against EGFR-positive malignancies.

Inhibition of IGF1-R overcomes IGFBP7-induced chemotherapy resistance in T-ALL

BACKGROUND

T-cell acute lymphoblastic leukemia (T-ALL) is a genetically heterogeneous disease with the need for treatment optimization. Previously, high expression of Insulin-like growth factor binding protein 7 (IGFBP7), a member of the IGF system, was identified as negative prognostic factor in adult T-ALL patients. Since aberrant IGFBP7 expression was observed in a variety of neoplasia and was relevant for prognosis in T-ALL, we investigated the functional role of IGFBP7 in Jurkat and Molt-4 cells as in vitro models for T-ALL.

METHODS

Jurkat and Molt-4 cells were stably transfected with an IGFBP7 over-expression vector or the empty vector as control. Proliferation of the cells was assessed by WST-1 assays and cell cycle status was measured by flow-cytometry after BrDU/7-AAD staining. The effect of IGFBP7 over-expression on sensitivity to cytostatic drugs was determined in AnnexinV/7-AAD assays. IGF1-R protein expression was measured by Western Blot and flow-cytometric analysis. IGF1-R associated gene expression profiles were generated from microarray gene expression data of 86 T-ALL patients from the Microarrays Innovations in Leukemia (MILE) multicenter study.

RESULTS

IGFBP7-transfected Jurkat cells proliferated less, leading to a longer survival in a nutrient-limited environment. Both IGFBP7-transfected Jurkat and Molt-4 cells showed an arrest in the G0/G1 cell cycle phase. Furthermore, Jurkat IGFBP7-transfected cells were resistant to vincristine and asparaginase treatment. Surface expression and whole protein measurement of IGF1-R protein expression showed a reduced abundance of the receptor after IGFBP7 transfection in Jurkat cells. Interestingly, combination of the IGF1-R inhibitor NPV-AEW541 restored sensitivity to vincristine in IGFBP7-transfected cells. Additionally, IGF1-R associated GEP revealed an up-regulation of important drivers of T-ALL pathogenesis and regulators of chemo-resistance and apoptosis such as NOTCH1, BCL-2, PRKCI, and TP53.

CONCLUSION

This study revealed a proliferation inhibiting effect of IGFBP7 by G0/G1 arrest and a drug resistance-inducing effect of IGFBP7 against vincristine and asparaginase in T-ALL. These results provide a model for the previously observed association between high IGFBP7 expression and chemotherapy failure in T-ALL patients. Since the resistance against vincristine was abolished by IGF1-R inhibition, IGFBP7 could serve as biomarker for patients who may benefit from therapies including IGF1-R inhibitors in combination with chemotherapy.

What can we expect from biomarkers for acute kidney injury?

Biomarkers for acute kidney injury have numerous potential roles to play both at the bedside and in the design and conduct of clinical trials. Given the heterogeneous nature of this disease and the difficulty, so far, in developing effective therapies, a strategy that deploys all of our available tools in the treatment and in study of treatments would seem prudent. In this review, we discuss how biomarkers will change the way we do we take care of patients with and do clinical trials in acute kidney injury and why, in fact, biomarkers are necessary.

Cell-cycle arrest and acute kidney injury: the light and the dark sides

Acute kidney injury (AKI) is a common consequence of systemic illness or injury and it complicates several forms of major surgery. Two major difficulties have hampered progress in AKI research and clinical management. AKI is difficult to detect early and its pathogenesis is still poorly understood. We recently reported results from multi-center studies where two urinary markers of cell-cycle arrest, tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) were validated for development of AKI well ahead of clinical manifestations—azotemia and oliguria. Cell-cycle arrest is known to be involved in the pathogenesis of AKI and this ‘dark side’ may also involve progression to chronic kidney disease. However, cell-cycle arrest has a ‘light side’ as well, since this mechanism can protect cells from the disastrous consequences of entering cell division with damaged DNA or insufficient bioenergetic resources during injury or stress. Whether we can use the light side to help prevent AKI remains to be seen, but there is already evidence that cell-cycle arrest biomarkers are indicators of both sides of this complex physiology.

Tissue Inhibitor Metalloproteinase-2 (TIMP-2)⋅IGF-Binding Protein-7 (IGFBP7) Levels Are Associated with Adverse Long-Term Outcomes in Patients with AKI

Tissue inhibitor metalloproteinase-2 (TIMP-2) and IGF-binding protein-7 (IGFBP7) have been validated for risk stratification in AKI. However, the association of urinary TIMP-2 and IGFBP7 with long-term outcomes is unknown. We evaluated the 9-month incidence of a composite end point of all-cause mortality or the need for RRT in a secondary analysis of a prospective observational international study of critically ill adults. Two predefined [TIMP-2]⋅[IGFBP7] cutoffs (0.3 for high sensitivity and 2.0 for high specificity) for the development of AKI were evaluated. Cox proportional hazards models were used to determine risk for the composite end point. Baseline [TIMP-2]⋅[IGFBP7] values were available for 692 subjects, of whom 382 (55.2%) subjects developed stage 1 AKI (defined by Kidney Disease Improving Global Outcomes guidelines) within 72 hours of enrollment and 217 (31.4%) subjects met the composite end point. Univariate analysis showed that [TIMP-2]⋅[IGFBP7]>2.0 was associated with increased risk of the composite end point (hazard ratio [HR], 2.11; 95% confidence interval [95% CI], 1.37 to 3.23; P<0.001). In a multivariate analysis adjusted for the clinical model, [TIMP-2]⋅[IGFBP7] levels>0.3 were associated with death or RRT only in subjects who developed AKI (compared with levels≤0.3: HR, 1.44; 95% CI, 1.00 to 2.06 for levels>0.3 to ≤2.0; P=0.05 and HR, 2.16; 95% CI, 1.32 to 3.53 for levels>2.0; P=0.002). In conclusion, [TIMP-2]⋅[IGFBP7] measured early in the setting of critical illness may identify patients with AKI at increased risk for mortality or receipt of RRT over the next 9 months.

Validation of cell-cycle arrest biomarkers for acute kidney injury after pediatric cardiac surgery

Background

The lack of early biomarkers for acute kidney injury (AKI) seriously inhibits the initiation of preventive and therapeutic measures for this syndrome in a timely manner. We tested the hypothesis that insulin-like growth factor-binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases-2 (TIMP-2), both inducers of G1 cell cycle arrest, function as early biomarkers for AKI after congenital heart surgery with cardiopulmonary bypass (CPB).

Methods

We prospectively studied 51 children undergoing cardiac surgery with CPB. Serial urine samples were analyzed for [TIMP-2]•[IGFBP7]. The primary outcome measure was AKI defined by the pRIFLE criteria within 72 hours after surgery.

Results

12 children (24%) developed AKI within 1.67 (SE 0.3) days after surgery. Children who developed AKI after cardiac surgery had a significant higher urinary [TIMP-2]•[IGFBP7] as early as 4 h after the procedure, compared to children who did not develop AKI (mean of 1.93 ((ng/ml)²/1000) (SE 0.4) vs 0.47 ((ng/ml)²/1000) (SE 0.1), respectively; p<0.05). Urinary [TIMP-2]•[IGFBP7] 4 hours following surgery demonstrated an area under the receiver-operating characteristic curve of 0.85. Sensitivity was 0.83, and specificity was 0.77 for a cutoff value of 0.70 ((ng/ml)²/1000).

Conclusions

Urinary [TIMP-2]•[IGFBP7] represent sensitive, specific, and highly predictive early biomarkers for AKI after surgery for congenital heart disease.

Trial Registration

www.germanctr.de/, DRKS00005062

Sirt1 induction confers resistance to etoposide-induced genotoxic apoptosis in thyroid cancers

Despite the favorable therapeutic outcomes reported in differentiated thyroid cancer (DTC), a significant proportion of DTC patients present with refractory behavior to conventional therapy. The sirtuin (Sirt) family has recently been implicated in the maintenance of cellular homeostasis under genotoxic stress. Here, we investigated the induction of Sirt1 expression by etoposide-induced genotoxic stress to gain insights into thyroid carcinogenesis and identify novel therapeutic targets. Immunohistochemical staining analyses of Sirt1 and Sirt3 were performed using human thyroid cancer tissues and matched normal tissues, and bioinformatic analyses were done using public repositories, including the Human Protein Atlas, BioGPS, NCBI Gene Expression Omnibus (GEO) profiles, and GeneNetwork. TPC1, FTC133 and FRO cells were used for molecular biological experiments including apoptosis assays, MTT, immunofluorescence staining and qRT-PCR assays. The IHC data and public repositories data consistently showed variable Sirt1 and Sirt3 expression patterns in normal thyroid follicular cells and papillary thyroid cancer cells. The induction of Sirt1 and Sirt3 was cell type-specific and the expression levels of these genes correlated with apoptotic cell death and cell viability after etoposide-induced genotoxic stress. Sirt1‑Foxp3 signaling-mediated regulation of Bax and p21 mRNA expression was a signature molecular event in TPC1 cells, which showed remarkable resistance to etoposide-induced genotoxic stress. The induction of Sirt1 and Sirt3 may be a determinant of thyroid cancer cell survival under genotoxic stress conditions. Further examination of the Sirt1-Foxp3 signal may improve our understanding of thyroid carcinogenesis and help identify new druggable targets.

Biomarkers of AKI: a review of mechanistic relevance and potential therapeutic implications

AKI is a common clinical condition associated with a number of adverse outcomes. More timely diagnosis would allow for earlier intervention and could improve patient outcomes. The goal of early identification of AKI has been the primary impetus for AKI biomarker research, and has led to the discovery of numerous novel biomarkers. However, in addition to facilitating more timely intervention, AKI biomarkers can provide valuable insight into the molecular mechanisms of this complex and heterogeneous disease. Furthermore, AKI biomarkers could also function as molecular phenotyping tools that could be used to direct clinical intervention. This review highlights the major studies that have characterized the diagnostic and prognostic predictive power of these biomarkers. The mechanistic relevance of neutrophil gelatinase-associated lipocalin, kidney injury molecule 1, IL-18, liver-type fatty acid-binding protein, angiotensinogen, tissue inhibitor of metalloproteinase-2, and IGF-binding protein 7 to the pathogenesis and pathobiology of AKI is discussed, putting these biomarkers in the context of the progressive phases of AKI. A biomarker-integrated model of AKI is proposed, which summarizes the current state of knowledge regarding the roles of these biomarkers and the molecular and cellular biology of AKI.

Interferon-γ induces senescence in normal human melanocytes

BACKGROUND

Interferon-γ (IFN-γ) plays an important role in the proceedings of vitiligo through recruiting lymphocytes to the lesional skin. However, the potential effects of IFN-γ on skin melanocytes and the subsequent contribution to the vitiligo pathogenesis are still unclear.

OBJECTIVE

To investigate the effects of IFN-γ on viability and cellular functions of melanocytes.

METHODS

Primary human melanocytes were treated with IFN-γ. Cell viability, apoptosis, cell cycle melanin content and intracellular reactive oxygen species (ROS) level were measured. mRNA expression was examined by real-time PCR. The release of interleukin 6 (IL-6) and heat shock protein 70 (HSP-70) was monitored by ELISA. β-galactosidase staining was utilized to evaluate melanocyte senescence.

RESULTS

Persistent IFN-γ treatment induced viability loss, apoptosis, cell cycle arrest and senescence in melanocytes. Melanocyte senescence was characterized as the changes in pigmentation and morphology, as well as the increase of β-galactosidase activity. Increase of p21Cip1/Waf1 protein was evident in melanocytes after IFN-γ treatment. IFN-γ induction of senescence was attenuated by siRNAs against p21, Janus kinase 2 (JAK2) or signal transducer and activator of transcription 1 (STAT1), but not by JAK1 siRNA nor by p53 inhibitor pifithrin-α. IFN-γ treatment increased the accumulation of intracellular ROS in melanocytes, while ROS scavenger N-acetyl cysteine (NAC) effectively inhibited IFN-γ induced p21 expression and melanocyte senescence. IL-6 and HSP-70 release was significantly induced by IFN-γ treatment, which was largely inhibited by NAC. The increase of IL-6 and HSP-70 release could also be observed in senescent melanocytes.

CONCLUSION

IFN-γ can induce senescence in melanocytes and consequently enhance their immuno-competency, leading to a vitiligo-prone milieu.

Insulin-like growth factor binding protein-related protein 1 and cancer

Insulin-like growth factor binding protein-related protein 1 (IGFBP-rP1) belongs to the IGFBP family whose members have a conserved structural homology. It has a low affinity for IGFs and a high affinity for insulin, suggesting that IGFBP-rP1 may have a biological function distinct from other members of the family. IGFBP-rP1 is ubiquitously expressed in normal human tissues and has diverse biological functions, regulating cell proliferation, apoptosis and senescence; it may also have a key role in vascular biology. Increasing evidence suggests that IGFBP-rP1 acts as a tumor suppressor. It elicits its biological effects by both insulin/IGF-dependent and -independent mechanisms. This paper provides a brief overview of the structure and regulation of IGFBP-rP1 and its various biological functions in cancer, as well as the underlying molecular mechanisms.

Loss of Igfbp7 causes precocious involution in lactating mouse mammary gland

BACKGROUND

Insulin like growth factors (IGFs) and their binding proteins (IGFBPs) are secreted peptides that play major roles in regulating the normal development and maturation of mammary gland. While Igfbp7 has been shown to decrease breast tumor growth, its role in regulating the normal mammary gland development has not been studied. To this end, we generated Igfbp7-null mice and examined the development and maturation of mammary glands in the virgin, pregnant and lactating animals.

RESULTS

We report here that loss of Igfbp7 significantly retards mammary gland development in the virgin animals. More significantly, the pregnant Igfpb7-null glands contained fewer alveolar structures and that during lactation these glands exhibit the morphological changes that are associated with involution. The transcriptome profile of the Igfbp7-null glands on the lactation day 3 revealed a distinct involution-related gene signature compared to the lactating WT glands. Interestingly, we found that the lactating Igfbp7-null glands exhibit increased expression of Stat3 and enhanced activation of (phosphorylated) Stat3, combined with decreased expression of Stat5 suggesting that the absence of Igfbp7 accelerates the onset of involution. We also found that in absence of Igfpb7, the lactating glands contain increased Igfbp5 protein along with decreased expression of IGF-1 Receptor and Akt activation. Finally, we show that during the normal course of involution, Igfbp7 expression is significantly decreased in the mammary gland.

CONCLUSION

Our data suggest that loss of Igfbp7 induces precocious involution possibly through diminished cell survival signals. Our findings identify Igfbp7 as major regulator of involution in the mammary gland.

Discovery and validation of cell cycle arrest biomarkers in human acute kidney injury

INTRODUCTION

Acute kidney injury (AKI) can evolve quickly and clinical measures of function often fail to detect AKI at a time when interventions are likely to provide benefit. Identifying early markers of kidney damage has been difficult due to the complex nature of human AKI, in which multiple etiologies exist. The objective of this study was to identify and validate novel biomarkers of AKI.

METHODS

We performed two multicenter observational studies in critically ill patients at risk for AKI - discovery and validation. The top two markers from discovery were validated in a second study (Sapphire) and compared to a number of previously described biomarkers. In the discovery phase, we enrolled 522 adults in three distinct cohorts including patients with sepsis, shock, major surgery, and trauma and examined over 300 markers. In the Sapphire validation study, we enrolled 744 adult subjects with critical illness and without evidence of AKI at enrollment; the final analysis cohort was a heterogeneous sample of 728 critically ill patients. The primary endpoint was moderate to severe AKI (KDIGO stage 2 to 3) within 12 hours of sample collection.

RESULTS

Moderate to severe AKI occurred in 14% of Sapphire subjects. The two top biomarkers from discovery were validated. Urine insulin-like growth factor-binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases-2 (TIMP-2), both inducers of G1 cell cycle arrest, a key mechanism implicated in AKI, together demonstrated an AUC of 0.80 (0.76 and 0.79 alone). Urine [TIMP-2]·[IGFBP7] was significantly superior to all previously described markers of AKI (P <0.002), none of which achieved an AUC >0.72. Furthermore, [TIMP-2]·[IGFBP7] significantly improved risk stratification when added to a nine-variable clinical model when analyzed using Cox proportional hazards model, generalized estimating equation, integrated discrimination improvement or net reclassification improvement. Finally, in sensitivity analyses [TIMP-2]·[IGFBP7] remained significant and superior to all other markers regardless of changes in reference creatinine method.

CONCLUSIONS

Two novel markers for AKI have been identified and validated in independent multicenter cohorts. Both markers are superior to existing markers, provide additional information over clinical variables and add mechanistic insight into AKI.

TRIAL REGISTRATION

ClinicalTrials.gov number NCT01209169.

Regulation of DCIS to invasive breast cancer progression by Singleminded-2s (SIM2s)

Singleminded-2s (SIM2s) is a member of the bHLH/PAS family of transcription factors and a key regulator of mammary epithelial cell differentiation. SIM2s is highly expressed in mammary epithelial cells and down regulated in human breast cancer. Loss of Sim2s causes aberrant mouse mammary ductal development with features suggestive of malignant transformation, whereas over-expression of SIM2s promotes precocious alveolar differentiation in nulliparous mouse mammary glands, suggesting that SIM2s is required for establishing and enhancing mammary gland differentiation. To test the hypothesis that SIM2s regulates tumor cell differentiation, we analyzed SIM2s expression in human primary breast ductal carcinoma in situ (DCIS) samples and found that SIM2s is lost with progression from DCIS to invasive ductal cancer (IDC). Utilizing a MCF10DCIS.COM progression model, we have shown that SIM2s expression is decreased in MCF10DCIS.COM cells compared to MCF10A cells and reestablishment of SIM2s in MCF10DCIS.COM cells significantly inhibits growth and invasion in vitro and in vivo. Analysis of SIM2s-MCF10DCIS.com tumors showed that SIM2s promoted a more differentiated tumor phenotype including the expression of a broad range of luminal markers (CSN2 (β-casein), CDH1 (E-cadherin), and KER18 (keratin-18)) and suppressed genes associated with stem cell maintenance and a basal phenotype (SMO (smoothened), p63, SLUG (snail-2), KER14 (keratin-14) and VIM (vimentin)). Furthermore, loss of SIM2s expression in MCF10DCIS.COM xenografts resulted in a more invasive phenotype and increased lung metastasis likely due to an increase in hedgehog signaling and matrix metalloproteinase expression. Together, these exciting new data support a role for SIM2s in promoting human breast tumor differentiation and maintaining epithelial integrity.