Abstract P6-06-01: Analyzing the physical and functional protein interaction landscape of breast cancer

A key unanswered question in cancer genetics is how different mutations, dispersed across a multitude of genes, elicit similar pathology and patient outcomes. The answer may lie in understanding the molecular networks and protein complexes (i.e. signaling pathways, chromatin architecture, etc) in cancer and mapping mutated genes into the complexes and pathways in which they function. Determining how systematic interaction networks are wired in cancer cells and how different mutations perturb these networks will guide the search for new cancer genes and provide a platform for integrating patient data to make biological and clinical predictions more accurate. The goal of this study is to uncover the comprehensive protein-protein interaction networks and pathways in various breast cancer subtypes to better understand how mutated cancer genes and genomes hijack and re-wire pathways and complexes during the course of breast tumorigenesis.

Here we catalog protein-protein interactions for 40 genes recurrently mutated in breast cancer, using affinity purification and mass spectrometry. To identify co-associated proteins, cDNA clones expressing each protein were tagged with 3xFLAG at either N or C-terminus and introduced into MCF10A (non-tumorigenic “healthy” control), MCF7 (luminal A subtype), and MDA-MB-231 (claudin-low) cells using doxycycline-inducible lentiviral vectors. For proteins with prevalent pathogenic mutations (e.g. PIK3CA-H1047R, BRCA1-C61G), mutant cDNA clones were also analyzed in parallel. Our interaction network reveals subtype and mutation-specific protein-protein interactions, many of which are not previously reported. Given that genes encoding components of a protein complex or a biological pathway often share similar phenotype upon genetic perturbation, we genetically knocked out genes interacting with DNA damage response (DDR) proteins using CRISPR/Cas9, and found multiple novel interacting genes whose knockout results in significant PARPi (olaparib) and/or cisplatin sensitivity. This result not only functionally validates the physical protein interactions, but also demonstrates that our interactome mapping approach can helps identify newdruggable vulnerabilities in cancer cells.

We anticipate the breast cancer interactome study will uncover aberrant pathways and protein complexes uniquely operating in breast cancer cells, and thus pinpoint proteins that may potentially serve as distinct biomarkers or therapeutic targets for tumors having the same or similar subtypes and/or genomic mutations.

Citation Format: Kim M, Kim K, Tutuncuoglu B, Soucheray M, Swaney D, Zheng F, Park J, O'Leary P, Coppé J-P, van 't Veer L, Ashworth A, Ideker T, Krogan N. Analyzing the physical and functional protein interaction landscape of breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-06-01.

Genomewide analysis of 6-methyladenine DNA in peripheral blood mononuclear cells of systemic lupus erythematosus

Aim

The aim of this paper is to explore the expression of 6-methyladenine (6mA) DNA and to elucidate its gene regulation role in systemic lupus erythematosus (SLE).

Methods

Twenty SLE patients and 20 normal control healthy individuals (HCs) were included in this study. Genomic DNA was isolated from peripheral blood mononuclear cells and subsequently underwent 6mA-immunoprecipitation-sequencing (6mA-IP-Seq) after DNA quality control and 6mA precipitation. Bioinformation analysis was applied to the raw data comparing 6mA levels between SLE patients and HCs.

Results

We identified 5462 hypermethylation and 431 hypomethylation genes in PBMCs of individuals with SLE, which indicated that a high level of 6mA participates in the pathogenesis of SLE. Gene ontology analysis revealed that hypermethylation genes might regulate the inflammatory process, which has been well documented in the pathogenesis of SLE.

Conclusion

6mA may be involved in the initial development of SLE, which may lead to its potential use as an early diagnostic marker and therapeutic target.

Removal of Cr (VI) from Simulated and Leachate Wastewaters by Bentonite-Supported Zero-Valent Iron Nanoparticles

Zero-valent iron (Fe⁰) nanoparticles (NPs) have shown excellent ability to remove contaminants hexavalent chromium (Cr(VI)) from aquatic systems. Use of support materials can help to prevent oxidation and aggregation of Fe⁰NPs, and thus enhance their remediation efficiency. However, most previous studies were conducted using artificially synthetic wastewater, and little is known on the remediation effects of supported Fe⁰NPs on actual wastewaters containing Cr(VI). Here, bentonite-supported Fe⁰NPs (BFe⁰NPs) with 1–5% of bentonite were prepared and characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Batch experiments were performed to study Cr(VI) removal by the selected BFe⁰NPs from a simulated wastewater and a leachate wastewater originating from a Cr slag heap-polluted soil. The results show that Fe⁰NPs were uniformly dispersed on the bentonite, leading to a decreased aggregation of NPs, and the optimal mass ratio of bentonite was 4%. Batch experiment results show that lower pH values favored Cr(VI) removal by BFe⁰NPs. The removal percentage of Cr(VI) was higher than 90% for both wastewaters when the pH value was 2.0, but decreased significantly as pH value increased. Cr(VI) removal reaction was quite fast within the initial 10 min, and at least 85% of Cr(VI) was removed for both wastewaters. Cr(VI) removal percentage increased with increasing BFe⁰NPs dosages ranging from 30 to 60, but remained almost unchanged when the Fe/Cr mass ratio increased to above 60. The reaction of BFe⁰NPs to remove Cr(VI) followed the pseudo second-order reaction model. In most cases, the removal rates of Cr(VI) were higher in simulated wastewater than in leachate wastewater, but all approached 100% at the optimal conditions. Our present results show that BFe⁰NPs with 4% bentonite are efficient for treatment of Cr(VI)-containing wastewaters.

P2Y12 deficiency in mouse impairs noradrenergic system in brain, and alters anxiety-like neurobehavior and memory

Purinergic receptor P2Y₁₂ (P2Y₁₂ ), a G protein-coupled purinergic receptor, is widely distributed in nervous system and involved in the progression of neurological diseases such as multiple sclerosis and neuropathic pain. The central noradrenergic system actively participates in a number of neurophysiological processes. Nevertheless, whether there is any direct relevance between P2Y₁₂ and noradrenergic signal transduction remains unknown. In the present study, we tested the hypothesis that lack of P2Y₁₂ impaired noradrenergic signal transduction in mouse brain. Our results showed that P2Y₁₂ knockout (KO) mice exhibited increased anxiety-like behavior in the open-field test (OFT) and elevated plus maze test and displayed deficits in memory in the radial-arm maze test (RAMT) and Morris water maze test (MWMT). They also exhibited reduced locomotion in the OFT and MWMT. Moreover, loss of P2Y₁₂ decreased the level of noradrenaline and the expression of noradrenergic α receptors, subtypes α2 (ARα2b) in mouse cerebellum and hippocampus. Meanwhile, it hampered the protein kinase A (PKA)/cAMP response element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF) signaling pathway in these brain regions. Taken together, our results showed for the first time that P2Y₁₂ KO altered the anxiety, memory and locomotion of mice, which was closely associated with abnormal state of noradrenergic system in the brain. The findings implicate that P2Y₁₂ plays an indispensable role in noradrenergic signal transduction; its deficit is insufficient to limit anxiety responses or supports cognitive performance and activity.

Role of TIM-3 in ovarian cancer

Evidences have suggested that immunotherapy for ovarian cancer is effective. Immune checkpoints have emerged in the field of cancer immunotherapy. Multiple studies have shown negative regulation of TIM-3 expression on CD4⁺ and CD8⁺ T cells and other immunocytes. Overexpression of TIM-3 in innate immune cells has been found in certain types of tumor. The blockade of TIM-3 leads to sustained anti-tumor reactions. TIM-3 plays an inhibitive role for immunity in ovarian cancer. TIM-3 is involved in the development of various subtypes of ovarian cancer and thus has the potential to be a therapeutic target for treatment of ovarian cancer.

Embelin attenuates adipogenesis and lipogenesis through activating canonical Wnt signaling and inhibits high-fat diet-induced obesity

BACKGROUND

Recent studies suggest that Embelin, a natural plant extract might have the potential to prevent body weight gain in rats. However, the mechanisms involved remain to be elucidated.

METHODS

Effects of Embelin on adipocyte differentiation and lipogenesis were studied in murine ST2 stromal cells and C3H10T1/2 mesenchymal cells. The mechanisms through which Embelin regulates adipogenic differentiation and lipogenesis were explored. The in vivo anti-obesity effects of Embelin in high-fat diet (HFD)-induced obesity mice and possible transcriptional impact were investigated.

RESULTS

Embelin treatment suppressed ST2 and C3H10T1/2 cells to proliferate, and differentiate into mature adipocytes, along with the inhibition of adipogenic factors peroxisome proliferator-activated receptor γ, CCAAT/enhancer binding protein-α, adipocyte protein 2 and adipsin. Embelin treatment also decreased the expression levels of lipogenic factors sterol regulatory element-binding protein 1, fatty acid synthase, acetyl-CoA carboxylase 1 and stearoyl-Coenzyme A desaturase 1. Embelin promoted the translocation of β-catenin from the cytoplasm into the nucleus in C3H10T1/2. The nuclear protein levels of β-catenin and TCF-4 were increased following Embelin treatment. Furthermore, Dickkopf-1 (Dkk1) expression was downregulated by Embelin, and overexpression of Dkk1 in C3H10T1/2 reversed the inhibition of adipogenesis and lipogenesis by Embelin. In vivo studies showed that Embelin treatment reduced the gain of body weight and fat, decreased the serum level of triglycerides, free fatty acid and total cholesterol, and improved glucose tolerance and insulin resistance in HFD-fed mice. Moreover, Embelin blocked induction of adipogenic and lipogenic factors and Dkk1 in adipose tissue in HFD-fed mice.

CONCLUSIONS

The present work provides evidences that Embelin is effective in inhibiting adipogenesis and lipogenesis in vitro and the mechanisms may involve canonical Wnt signaling. Embelin has the potential to prevent body weight gain and fat accumulation, and to improve obesity-related glucose tolerance impairment and insulin resistance in the HFD-fed mice.

The segregation resistance of the Pt2ML/Os/Pd3Al sandwich catalyst for oxygen reduction reaction: a density functional theory study

Pt_1ML/Pd₃Al, which comprises a Pd₃Al core protected by a Pt monolayer, may experience Al dealloying because of the strong affinity of Al toward O. To circumvent this issue, the Pt_2ML/Os/Pd₃Al catalyst has been designed to suppress the migration of Al by inserting an Os monolayer at the interface between the Pd₃Al core and two Pt monolayers. On the basis of segregation energies, Al leaching from the core to the 1st layer is determined to be endothermic even under O coverage, indicating an energetic preference for Al to reside in the core structure. The Pt_2ML/Os/Pd₃Al catalyst benefits from the energetic disadvantage of the inward movement of Os and the presence of the 2 ML Pt layer. As an ORR electrocatalyst, the relatively weak adsorption ability of Pt_2ML/Os/Pd₃Al suggests improved ORR activity. Finally, a representative OOH association mechanism with low reaction barriers of 0.46, 0.31, 0.38 and 0.41 eV for the OOH formation, OOH dissociation, OH formation and H₂O formation steps suggests that the catalyst can effectively activate the O-O bond and eliminate OH, which can act as a catalytic poison. These findings suggest the design of stable sandwich catalysts as potential candidates for ORR electrocatalysis.

Development of an indirect ELISA based on a truncated S protein of the porcine epidemic diarrhea virus

Porcine epidemic diarrhea (PED) is a highly contagious, enteric disease of swine caused by the porcine epidemic diarrhea virus (PEDV). To find a suitable ELISA method to assess the infection of PEDV and the effectiveness of vaccines, we developed and evaluated an indirect enzyme-linked immunosorbent assay (iELISA) based on a truncated recombinant spike (S) protein expressed in Escherichia coli. The parameters of the iELISA were optimized, and the cutoff value determined as 0.259 by analyzing optical density (OD) values of 80 PEDV negative sera confirmed by western blot. Repeatability tests revealed that the coefficients of variation of positive sera within and between runs were both less than 10%. Cross-reactivity assays demonstrated that iELISA was PEDV-specific. A virus neutralization test with sera of 7 different OD values showed a positive correlation between the OD values and virus neutralization. The results suggest this iELISA is specific, sensitive, and repeatable. Further studies should focus on the relationship between OD values of sera and its virus neutralization.

Efficacy of bisphosphonates against osteoporosis in adult men: a meta-analysis of randomized controlled trials

This meta-analysis of published randomized controlled trials (RCTs) aimed to analyze the efficacy of administration of bisphosphonates in men with osteoporosis. Compared with placebo, bisphosphonates could reduce the risk of vertebral and non-vertebral fractures, reduce bone-specific alkaline phosphatase (BSAP) and C-terminal telopeptide of type I collagen (CTX), and increase bone mineral density (BMD).

INTRODUCTION

Bisphosphonates are well-investigated antiresorptive medications, approved as first-line drugs for osteoporosis in postmenopausal women. However, there is a paucity of high-quality evidence regarding the efficacy of bisphosphonates administered for osteoporosis in adult men. The aim of this meta-analysis was to analyse the efficacy of administration of bisphosphonates in men based on published RCTs.

METHODS

PubMed, Embase, MEDLINE, and the Cochrane library were searched, and mean differences were calculated to evaluate the efficacy of bisphosphonates on reducing the risk of vertebral and non-vertebral fracture, reducing bone-turnover biomarkers, and increasing BMD.

RESULTS

Nine RCTs were included and the total number of participants was 2464. Compared with placebo, the efficacy of bisphosphonates on vertebral and non-vertebral fracture risk reduction was confirmed [for vertebral fracture, RR (95 % CI) 0.36 (0.24, 0.56), P < 0.01; for non-vertebral fracture, RR (95 % CI) 0.52 (0.32, 0.84), P < 0.01)] and heterogeneity was insignificant. The efficacy of bisphosphonates on reducing BSAP [MD (95 % CI) -24.41 (-26.19, -22.62), P < 0.01) and CTX [MD (95 % CI) -34.51 (-41.03, -27.98), P < 0.01)] was significant. A sensitivity analysis was applied to explain the origination of heterogeneity in analysis of decreasing of BSAP. BMD was increased in the bisphosphonates group compared with the control group at lumbar spine, femoral neck, and total hip (P < 0.01), and the heterogeneity of all comparisons was significant.

CONCLUSION

Compared with placebo, bisphosphonates could decrease the risk of vertebral and non-vertebral fractures, reduce BSAP and CTX, and increase BMD in men with osteoporosis.

Blockade of Extracellular HMGB1 Suppresses Xenoreactive B Cell Responses and Delays Acute Vascular Xenogeneic Rejection

Blockade of extracellular high mobility group box 1 (HMGB1) can significantly prolong murine cardiac allograft survival. Here, we determined the role of HMGB1 in xenotransplantation. Sprague-Dawley rat hearts were transplanted heterotopically into BALB/c mice. Xenografts without any treatment developed predominant acute vascular rejection within 6 days. Both passively released HMGB1 from xenografts and actively secreted HMGB1 from infiltrated immune cells were significantly increased after xenotransplantation. HMGB1-neutralizing antibody treatment significantly prolonged xenograft survival and attenuated pathologic damage, immune cell infiltration, and HMGB1 expression and release in the xenografts. Compared to control IgG treatment evaluated at study endpoint, treatment with HMGB1-neutralizing antibody markedly suppressed xenoreactive B cell responses, as evidenced by the significant inhibition of anti-rat antibody production and deposition in xenografts at Day 6 posttransplant. Furthermore, treatment with anti-HMGB1 antibody suppressed B cell activation and reduced IFN-γ and IL-17A production after xenotransplantation. These results demonstrate for the first time that HMGB1 plays an important role in mediating acute xenograft rejection. Thus, we have shown that neutralization of extracellular HMGB1 can significantly inhibit xenoreactive B cell responses and delay xenograft rejection in a rat-to-mouse model of xenotransplantation, uncovering new insights in the role of HMGB1 in transplantation.

Increased expression of macrophage migration inhibitory factor in aorta of patients with coronary atherosclerosis

AIM

The aim of the present study was to investigate the changes of macrophage migration inhibitory factor (MIF) in the aorta of patients with coronary atherosclerosis and to evaluate the relationship between aortic expression levels of MIF and atherosclerotic risk factors.

METHODS

We collected discarded aortic specimens from patients (N.=36) undergoing coronary artery bypass graft surgery (CABG), and studied the presence and distribution of MIF by immunohistochemistry. The arterial tissues from 10 subjects without known atherosclerosis through the kidney donation program were taken as control group. The preoperative serum triglycerides, total cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol, lipoprotein(a), apolipoprotein A, apolipoprotein B, total bilirubin, direct bilirubin, and indirect bilirubin levels of patients were examined and the coronary angiography was performed in order to assess the severity of atherosclerotic lesions.

RESULTS

MIF was detectable in aorta from CABG patients. The aortic MIF expression was elevated in smokers, and patients with hypertension or diabetes. In addition, the aortic MIF expression was associated with the levels of triglycerides, total cholesterol, low density lipoprotein cholesterol, lipoprotein (a), apolipoprotein B, total bilirubin, direct bilirubin, indirect bilirubin and coronary severity scores in simple regression analysis. However, the expression of MIF was only correlated to coronary severity scores in multiple regression analysis.

CONCLUSION

MIF is overexpressed in aorta from patients with coronary atherosclerosis and the aortic MIF expression is correlated with the severity of coronary artery disease.

Propofol suppresses proliferation and invasion of gastric cancer cells via downregulation of microRNA-221 expression

Propofol is one of the extensively and commonly used intravenous anesthetic agents. The current study aimed to evaluate the effects of propofol on the behavior of human gastric cancer cells and the molecular mechanisms of this activity. The effects of propofol on SGC7901 and AGS cell proliferation, apoptosis, and invasion were detected by MTT assay, flow cytometric analysis, and matrigel invasion assay. Real-time polymerase chain reaction (PCR) was used to assess microRNA (miR)-221 expression. miR-221 mimics were transfected into SGC7901 and AGS cells to assess the role of miR- 221 in propofol-induced anti-tumor activity. Propofol significantly inhibited cell proliferation and invasion and promoted apoptosis of SGC7901 and AGS cells. Propofol also efficiently reduced miR-221 expression. Moreover, transfection of miR-221 mimics reversed the effects of propofol on the biological behavior of gastric cancer cells. Propofol can effectively inhibit proliferation and invasion and induce apoptosis of gastric cancer cells through, at least partly, downregulation of miR-221 expression.

Reverse-dipper pattern of blood pressure may predict lacunar infarction in patients with essential hypertension

BACKGROUND AND PURPOSE

The fluctuation of circadian blood pressure (BP) is of great diversity in patients with essential hypertension and may provide significant prognostic value for stroke. However, it remains uncertain whether reverse-dipper pattern of BP influences the incidence of lacunar infarction in hypertensive patients.

METHODS

In the current study, 362 hypertensive patients (195 males, 167 females) were enrolled. BP patterns were evaluated with 24-h ambulatory BP monitoring (ABPM). Multinomial logistic regression was applied to analyse the possible relationships between lacunar infarction and various clinical risk factors such as ABPM.

RESULTS

A total of 93 patients (25.7%) had reverse-dipper BP pattern. Non-dipper pattern of BP was observed in 179 hypertensive patients (49.4%) and dipper pattern in 90 patients (24.9%). The percentage of lacunar infarction was the highest in the patients with reverse-dipper pattern compared with pure hypertension or atherothrombotic cerebral infarction (P < 0.05). After multinomial logistic regression analysis, reverse-dipper pattern of BP (odds ratio 2.492; 95% confidence interval 1.133-5.479; P < 0.05) and age (odds ratio 1.084; 95% confidence interval 1.047-1.123; P < 0.01) were found to be directly associated with lacunar infarction.

CONCLUSIONS

Reverse-dipper BP pattern may serve as an independent risk factor for lacunar infarction and more personalized BP management should be offered to the patients who have elevated nocturnal BP.

Calreticulin promotes angiogenesis via activating nitric oxide signalling pathway in rheumatoid arthritis

Calreticulin (CRT) is a multi-functional endoplasmic reticulum protein implicated in the pathogenesis of rheumatoid arthritis (RA). The present study was undertaken to determine whether CRT was involved in angiogenesis via the activating nitric oxide (NO) signalling pathway. We explored the profile of CRT expression in RA (including serum, synovial fluid and synovial tissue). In order to investigate the role of CRT on angiogenesis, human umbilical vein endothelial cells (HUVECs) were isolated and cultured in this study for in-vitro experiments. Our results showed a significantly higher concentration of CRT in serum (5·4 ± 2·2 ng/ml) of RA patients compared to that of osteoarthritis (OA, 3·6 ± 0·9 ng/ml, P < 0·05) and healthy controls (HC, 3·7 ± 0·6 ng/ml, P < 0·05); and significantly higher CRT in synovial fluid (5·8 ± 1·2 ng/ml) of RA versus OA (3·7 ± 0·3 ng/ml, P < 0·05). High levels of CRT are expressed in synovial membrane localized predominantly to inflammatory cells and synovial perivascular areas in both the lining and sublining layers of RA synovial tissue (RAST). Increased nitric oxide (NO) production and phosphorylation level of endothelial nitric oxide synthase (eNOS) were measured in HUVECs following CRT stimulation, while the total eNOS expression was not significantly changed. Furthermore, CRT promoted the proliferation, migration and tube formation of HUVECs, which were significantly inhibited by a specific eNOS inhibitor. These findings suggested that CRT may be involved in angiogenesis events in RA through NO signalling pathways, which may provide a potential therapeutic target in the treatment of RA.