[Pathological diagnosis of lung cancer based on deep transfer learning]

Objective: To establish an artificial intelligence (AI)-assisted diagnostic system for lung cancer via deep transfer learning. Methods: The researchers collected 519 lung pathologic slides from 2016 to 2019, covering various lung tissues, including normal tissues, adenocarcinoma, squamous cell carcinoma and small cell carcinoma, from the Beijing Chest Hospital, the Capital Medical University. The slides were digitized by scanner, and 316 slides were used as training set and 203 as the internal test set. The researchers labeled all the training slides by pathologists and establish a semantic segmentation model based on DeepLab v3 with ResNet-50 to detect lung cancers at the pixel level. To perform transfer learning, the researchers utilized the gastric cancer detection model to initialize the deep neural network parameters. The lung cancer detection convolutional neural network was further trained by fine-tuning of the labeled data. The deep learning model was tested by 203 slides in the internal test set and 1 081 slides obtained from TCIA database, named as the external test set. Results: The model trained with transfer learning showed substantial accuracy advantage against the one trained from scratch for the internal test set [area under curve (AUC) 0.988 vs. 0.971, Kappa 0.852 vs. 0.832]. For the external test set, the transferred model achieved an AUC of 0.968 and Kappa of 0.828, indicating superior generalization ability. By studying the predictions made by the model, the researchers obtained deeper understandings of the deep learning model. Conclusions: The lung cancer histopathological diagnostic system achieves higher accuracy and superior generalization ability. With the development of histopathological AI, the transfer learning can effectively train diagnosis models and shorten the learning period, and improve the model performance.

Knockdown of TRIM24 suppresses growth and induces apoptosis in acute myeloid leukemia through downregulation of Wnt/GSK-3β/β-catenin signaling

Tripartite motif-containing protein 24 (TRIM24) has currently emerged as a crucial cancer-related gene present in a wide range of human cancer types. However, the involvement of TRIM24 in acute myeloid leukemia (AML) has not been well investigated. The present study aims to investigate the significance, cellular function, and potential regulatory mechanism of TRIM24 in AML. We found that TRIM24 expression was significantly upregulated in AML compared with normal tissues. AML patients with low expression of TRIM24 had higher survival rates than those expressing TRIM24 at higher levels. High expression of TRIM24 was also detected in AML cells and its knockdown markedly restricted proliferation and promoted apoptosis in AML cells. Further investigation revealed that TRIM24 contributed to the regulation of Wnt/β-catenin signaling, which was associated with modulating the phosphorylation status of glycogen synthase kinase-3β (GSK-3β). Inactivation of GSK-3β partially reversed the TRIM24 knockdown-mediated antitumor effects observed in AML cells. Furthermore, knockdown of TRIM24 retarded the growth of AML-derived xenograft tumors in nude mice in vivo. Overall, these findings demonstrate that knockdown of TRIM24 impedes the AML tumor growth through the modulation of Wnt/GSK-3β/β-catenin signaling. These findings highlight the potential TRIM24 as an attractive anticancer target to treat AML.

Acid-sensitive PEGylated paclitaxel prodrug nanoparticles for cancer therapy: Effect of PEG length on antitumor efficacy

Paclitaxel is one of the most widely used anticancer agents, but strong side effects and low bioavailability limit its clinical efficacy. The use of tumor microenvironment-responsive prodrugs is promising to solve these problems, and a smart linkage is crucial to achieve the efficient release of paclitaxel from such prodrugs in tumor. Herein, an acid-responsive acetone-based acyclic ketal linkage is used to construct paclitaxel prodrugs with different length of poly(ethylene glycol) (PEG). The PEGylated acetone-based acyclic-ketal-linked prodrugs of paclitaxel (PKPs) self-assembled into nanoparticles that were stable in normal physiological environment but released paclitaxel rapidly in mildly acidic environment in tumor. The length of PEG had considerable impact on size and critical micelle concentration of PKP nanoparticles, thereby affecting prodrug hydrolysis kinetics, pharmacokinetics, biodistribution, and antitumor activity for PKP nanoparticles. In an A2780 xenograft mouse model, PKP nanoparticles displayed improved pharmacokinetics and superior antitumor efficacy against Taxol. Our results demonstrate that acyclic-ketal-based prodrugs are useful for the development of acid-responsive anticancer nanomedicines.

[Pathological characteristics and molecular diagnosis of non-tuberculosis Mycobacterium lung disease]

Objective: To investigate the clinicopathological features of non-tuberculosis mycobacterial lung disease and the role of molecular pathology in diagnosis. Methods: Forty-five formalin-fixed, paraffin embedded (FFPE) specimens were collected from the Department of Pathology, Beijing Chest Hospital from February 2016 to August 2019. The clinical, imaging and histopathologic features, bacteriologic data and morphologic characteristics of acid fast bacilli (AFB) were analyzed retrospectively. Specific gene sequence IS6110 of Mycobacterium tuberculosis (MTB) was detected by fluorescence PCR. Identification of Mycobacteria was by melting curve method. Fifty cases of pulmonary tuberculosis were selected in the same period as control. Results: The NTM lung cases included 18 cases (40.0%, 18/45) of M. intracellulare, eight cases (17.8%, 8/45) of M. xenopi, six cases (13.3%, 6/45) of M. avium, six cases (13.3%, 6/45) of M. kansasii, six cases (13.3%, 6/45) of M. chelonae and one case (2.2%, 1/45) of M. simiae. Histopathologically, there were necrotizing granulomas in 34 cases (75.6%, 34/45), non-necrotizing granuloma in one case (2.2%, 1/45) and non-granulomatous lesions in 10 cases (22.2%, 10/45). The necrosis was pink necrosis, basophilic necrosis rich in nuclear fragments and suppurative necrosis. Pulmonary TB showed more pink necrosis and basophilic necrosis, the difference was statistically significant (χ(2)=10.270, P=0.001; χ(2)=7.449, P=0.006). Seventeen cases (37.8%, 17/45) of NTM lung disease showed giant multinucleated giant cells, which were significantly different from those in pulmonary tuberculosis group (χ(2)=13.446, P<0.01). The number and morphology of AFB were also different. More AFB were found in M. intracellular cases and significant AFB were easily seen in M. kansasii infection. Conclusions: M. tuberculosis and NTM cannot be reliably differentiated by histologic features or by AFB morphology. Molecular assays are important to distinguish tuberculosis from NTM lung disease.

A Phototheranostic Strategy to Continuously Deliver Singlet Oxygen in the Dark and Hypoxic Tumor Microenvironment

Continuous irradiation during photodynamic therapy (PDT) inevitably induces tumor hypoxia, thereby weakening the PDT effect. In PDT-induced hypoxia, providing singlet oxygen from stored chemical energy may enhance the cell-killing effect and boost the therapeutic effect. Herein, we present a phototheranostic (DPPTPE@PEG-Py NPs) prepared by using a 2-pyridone-based diblock polymer (PEG-Py) to encapsulate a semiconducting, heavy-atom-free pyrrolopyrrolidone-tetraphenylethylene (DPPTPE) with high singlet-oxygen-generation ability both in dichloromethane and water. The PEG-Py can trap the 1 O2 generated from DPPTPE under laser irradiation and form a stable intermediate of endoperoxide, which can then release 1 O2 in the dark, hypoxic tumor microenvironment. Furthermore, fluorescence-imaging-guided phototherapy demonstrates that this phototheranostic could completely inhibit tumor growth with the help of laser irradiation.

Modular Acid-Activatable Acetone-Based Ketal-Linked Nanomedicine by Dexamethasone Prodrugs for Enhanced Anti-Rheumatoid Arthritis with Low Side Effects

Given the physically encapsulated payloads with drug burst release and/or low drug loading, it is critical to initiate an innovative prodrug strategy to optimize the design of modular nanomedicines. Here, we designed modular pH-sensitive acetone-based ketal-linked prodrugs of dexamethasone (AKP-dexs) and formulated them as nanoparticles. We comprehensively studied the relationships between AKP-dex structure and properties, and we selected two types of AKP-dex-loaded nanoparticles for in vivo studies on the basis of their size, drug loading, and colloidal stability. In a collagen-induced arthritis rat model, these AKP-dex-loaded nanoparticles showed higher accumulation in inflamed joints and better therapeutic efficacy than free dexamethasone phosphate with less-severe side effects. AKP-dex-loaded nanoparticles may be useful for treating other inflammatory diseases and thus have great translational potential. Our findings represent an important step toward the development of practical applications for acetone-based ketal-linked prodrugs and are useful in the design of modular nanomedicines.

Multiresidue Gas Chromatographic Method for Determining Synthetic Pyrethroid Pesticides in Agricultural Products: Collaborative Study

Fourteen laboratories from 6 countries and regions participated in an international collaborative study to evaluate a multiresidue gas chromatographic (GC) method for determining 8 synthetic pyrethroid pesticides in grains, fruits, and vegetables. The study design was based on Youden’s matched-pairs principle for collaborative tests of analytical methods. Each laboratory analyzed 12 collaborative samples of wheat, oranges, and tomatoes as blind samples. Wheat samples were extracted with acetonitrile–water (2 + 1), while orange and tomato samples were extracted with acetone. Residues were partitioned into hexane, evaporated to dryness with a rotary evaporator, and then dissolved in hexane. The hexane extract was partitioned with acetonitrile and cleaned up on a 5% water-deactivated Florisil column with 6% ethyl ether in hexane as eluant. Residue concentrations were determined by GC with electron capture detection with split-less injection by comparison with single-point calibration standards. The appropriate standard concentration was determined by screening sample extracts before analysis. The multiresidue method was tested over the concentration range of 0.0951.909 mg/kg depending on the 8 different of pesticides and agricultural products analyzed in the collaborative study. Statistical analysis of data from 13 laboratories showed weighted average recoveries for 8 pyrethroids in wheat, oranges, and tomatoes at 0.105–1.909,0.095–1.909, and 0.105–0.954 mg/kg, respectively, ranging from 91.8 to 100.2%, from 88.1 to 100.6%, and from 88.2 to 101.5%, respectively. Reproducibility relative standard deviation values ranged from 6.46 to 17.74%, from 5.94 to 18.13%, and from 5.59 to 10.48%, respectively. Repeatability relative standard deviation values ranged from 6.34 to 10.84%, from 5.19 to 11.72%, and from 3.20 to 8.09%, respectively. The multiresidue GC method for determining synthetic pyrethroid pesticides in agricultural products has been adopted first action by AOAC INTERNATIONAL.

[The evaluation of modified cell infusion method to reduce febrile non-hemolytic transfusion reaction in CD(19) chimeric antigen receptor T cell threapy]

Objective: To retrospectively analyze the efficacy and safety of modified cell infusion method in reducing the incidence of febrile non-hemolytic transfusion reaction (FNHTR). Methods: A total of 69 patients were enrolled in the clinical trial of CD(19) chimeric antigen receptor T (CAR-T) cell treatment from February 2017 to October 2018. Study group received the modified cell infusion method, that 1×10(6) CAR-T cells were re-suspended in 2 mg human serum albumin with total volume of 20 ml and injected intravenously. The control group was intravenously administrated with CAR-T cell in 100 ml normal saline. The incidence of FNHTR, cytokine releasing syndrome (CRS) grade, cytokine level and efficacy were compared. Results: (1)The incidence of FNHTR in the study group was 21.1%, significantly lower than that in the control group (71%)(P=0.000). (2)There was no statistical difference in cell proliferation between the study group and the control group on day 4, 7, 14 and 21 after CAR-T cell infusion (P=10.223, 3.254, 5.551, 7.605). (3)There was no statistical difference in CRS grading between the study group and the control group (P=0.767). There was no statistical difference in the levels of interleukin 2 receptor (IL-2R), IL-6, tumor necrosis factor (TNF)-α between the two groups. (4)The C-reaction protein (CRP) level of the study group was lower than that of the control group on day 4 and 7 (P=0.026, 0.007). (5)There was no statistical difference of response rates in acute lymphocytic leukemia (ALL) and non-Hodgkin lymphoma (NHL) patients between the two groups (P(ALL)=0.842; P(NHL)=0.866). Conclusion: The modified cell infusion method in CD(19) CAR-T cell treatment reduces the incidence of treatment-related FNHTR. It does not affect the proliferation of CAR-T cells in vivo, the grading of CRS and the response rates.

[Comparative analysis of superb microvascular imaging and contrast-enhanced ultrasound in diagnosis of small renal masses]

Objective: To explore the value of superb microvascular imaging (SMI) and contrast- enhanced ultrasound (CEUS) in differential diagnosis of small renal masses. Methods: A total of 84 patients with 86 lesions of renal masses were collected from October 2016 to March 2018 in Tianjin Medical University Cancer Institute and Hospital. There were 56 males and 28 females,aged from 29 to 76 years old,with an average age of (54±10) years old. These tumors were all examined by using SMI and CEUS. And the imaging diagnostic results were compared based on the pathological results. Adler semi quantitative analysis of blood flow grading of the tumors were evaluated in SMI,and the evaluation standard was as follows:0-1 grade was benign, 2-3 grade was malignant. Besides,the patterns and enhancement of the small renal masses were observed in CEUS. The main diagnostic criteria of malignant tumors were "fast forward" , "rapid regression" and "high perfusion" . Some special types of renal cell carcinoma were diagnosed by "slow in" , "rapid regression" and "hypo-perfusion" . Benign tumors were diagnosed by "slow in" , "slow down" and "hypo-perfusion" . Results: Among 86 cases, 76 cases were confirmed as malignant masses and 10 cases were confirmed as benign masses by pathological diagnosis. By SMI, Adler grade of 89.5% (68/76) malignant tumors were 2-3, Adler grade of 6/10 benign tumors were 0-1. By CEUS, 77.6% (59/76) of malignant tumors were "fast forward" , 82.9% (63/76) were "rapid regression" , 76.3% (58/76) were "high perfusion" ; 7/10 of benign tumors were "slow in" , 5/10 were "slow down" and 6/10 were "low perfusion" . The accuracy, sensitivity, specificity, positive predictive value, negative predictive value and AUC of SMI were 86.0%,89.5%, 60.0%, 94.4%,42.9% and 0.747 respectively. The values for CEUS were 89.5%, 92.1%, 70.0%,95.9%, 53.8% and 0.811 respectively.There was no statistical difference in diagnostic efficacy between CEUS and SMI (P=0.288). Conclusions: Although there is no statistical significance between SMI and CEUS, the accuracy, sensitivity and positive predictive value of SMI in the diagnosis of small renal masses are higher,which can clearly show micro-vessels and exquisitely detect the low-velocity blood flow in small renal masses. In brief,SMI provides a new method in the differential diagnosis of small renal masses.

[Timeless promotes the proliferation of hepatocellular carcinoma cell by reprogramming of glucose metabolism]

Objective: To explore the function and molecular mechanism of Timeless in promoting hepatocellular carcinoma (HCC) growth. Methods: The expression of Timeless in HCC and paracancer tissues were analyzed by using the public data of HCC. Timeless was overexpressed in MHCC97L cells and silenced in MHCC97H cells, respectively, and the expression of Timeless and its downstream molecules were detected by real-time PCR and western blot. The effects of Timeless on cell glycolysis, oxidative phosphorylation and proliferation were detected by the glucose uptake experiment, lactic acid detection experiment, the extracellular fluid pH detection experiment, cell oxygen consumption test and cell viability assay, respectively. Results: The level of Timeless in HCC tissue was significantly higher than that of paracancer tissue (P<0.05). The relative cellular glucose uptake levels in the groups of Timeless knockdown, including siTimeless-1 and siTimeless-2 group were 0.510±0.119 and 0.508±0.099, respectively, significantly different from that of control group (P<0.05); The relative cellular uptake level of Timeless overexpressed group was 1.953±0.324, significantly different from that of vector transfected group (P<0.05). The relative levels of lactic acid production in the siTimeless-1 and siTimeless-2 group were 0.579±0.096 and 0.550±0.120, respectively, significantly different from that of control group (P<0.05); The relative production level of lactic acid in the Timeless overexpressed group was 1.463±0.179, significantly different that of vector transfected group (P<0.05). The extracellular pH values of siTimeless-1 and siTimeless-2 group were 7.390±0.035 and 7.370±0.060, respectively, significantly different from that of control group (P<0.05); the extracellular pH value of Timeless overexpressed group was 7.130±0.031, significantly different than vector transfected group (P<0.05). Oxygen consumption rate of siTimeless-1 and siTimeless-2 group were 3.686±0.389 and 3.955±0.431, respectively, significantly higher than 1.690±0.297 of control group (P<0.05); Oxygen consumption rate of Timeless overexpressed group was 1.302±0.336, significantly lower than 3.185±0.262 of vector transfected group (P<0.05) Timeless inhibited the expression of p53. The cell glucose uptake, lactic acid production, the pH of extracellular culture medium and cell oxygen consumption of control group were not significantly different from that of Timeless and p53 co-silenced group [(si-Timeless+sip53) group] (P>0.05); the glucose uptake, the production of lactic acid, the pH of the extracellular culture medium and the oxygen consumption of Timeless co-transfected with p53 (Timeless+p53) group were not significantly different from those of vector transfected group (P>0.05). Timeless promoted the proliferation of HCC cells through inhibiting the expression of p53. Conclusion: Timeless promotes reprogramming of glucose metabolism and proliferation of HCC cells by inhibiting the p53-dependent signaling pathway.

The involvement and mechanism of febuxostat in non-alcoholic fatty liver disease cells

It has been proved that hyperuricemia is associated with non-alcoholic fatty liver disease (NAFLD). The xanthine oxidase (XO) inhibitor, febuxostat, decreases free fatty acids-induced fat accumulation in HFDT-fed mice. Here, it is shown that febuxostat attenuates fat accumulation and reactive oxygen species (ROS) in HepG2 cells. It was further found that the underlying mechanism is related to the reduction in expression of NLRP3/caspase-1/IL-18/IL-1beta and improved insulin resistance (IR). This finding highlights the possible molecular pathways involving NLRP3 activation for management of ROS and insulin IR. In conclusion, febuxostat may be a promising potential treatment for patients with NAFLD.

Comprehensive Identification of Guan-Xin-Shu-Tong Capsule via a Mass Defect and Fragment Filtering Approach by High Resolution Mass Spectrometry: In Vitro and In Vivo Study

The Guan-Xin-Shu-Tong capsule (GXSTC) is a well-known traditional Chinese medicine that is used for the treatment of coronary heart disease. Despite its common use in China, basic pharmacological research on its active components is limited. A comprehensive analytical method using quadrupole-time-of-flight mass spectrometry (Q-TOF/MS), specifically with the Triple TOF 5600 platform, was developed to characterize the compounds in the GXSTC powder itself (in vitro) as well as the active components in healthy and heart disease model rats after its oral administration (in vivo). The 5600 platform was operated in both positive and negative ion modes, before the raw data were processed using the extracted ion chromatography (EIC), mass defect filtering (MDF) and fragment filtering (FF) techniques. With the aid of reference compounds for retention time and fragment ion comparisons, 18 compounds were unambiguously identified in vitro. An additional 56 other compounds were tentatively characterized using the accurate quasi-molecular ion mass and Tandem mass spectrometry (MS/MS) fragmentation pattern strategies. Among them, 30 compounds were characterized based on the MDF and FF approaches. Normal rats in addition to hyperlipidemic (HL) and acute blood stasis (ABS) model rats were given a single oral dose of GXSTC solution for subsequent blood analysis at 1 and 2 h after administration. A total of 24 prototypecomponents and 20 metabolites derived from GXSTC were differentially detected across the three animal groups, including the absence of four phase II phenolic acid metabolites in the ABS group and the presence of three diterpenoid-related metabolites exclusive to the HL group. The use of reference compounds as well as the mass defect and fragment-filtering strategies were critical to identify GXSTC compounds in vitro and in vivo. This can be used for further quality control and pharmacological studies aimed at characterizing the active and potential beneficial compounds of this ancient medicine.

[Clinical observation on monovision of cataract surgery with different near addition]

Objective: To observe the influence on spectacle independence, satisfaction and visual function after cataract surgery monovision with different ADD. Methods: Prospective clinical study. All patients were collected from the department of ophthalmology, Shanghai JiaoTong University Affiliated Sixth People's Hospital who were diagnosed as bilateral cataract from Oct. 2013 to Mar. 2015. This study comprised 64 cases (128 eyes). All consecutive patients scheduled to undergo bilateral cataract phacoemulsification and implantation of a monofocal AcrySof IQ IOL. The average age of patients was (65.4± 6.0) years old, ranged from 51 to 70 years. 28 males and 36 females. According to the different demands of spectacle independence and living habits of patients, all cases were divided into two groups: MV1 group (32 patients), whose near addition being 1.25-1.75 D and MV2 group (32 patients), whose near addition being 2.25-2.75 D. Parameters 6 months postoperatively included binocular uncorrected distance, intermediate, and near visual acuities, stereo vision and refractive states were analyzed. Parameters of spectacle independence, subjective visual symptoms and patient satisfaction according to visual function questionnaire were analyzed at the same time. T test was used to compare uncorrected visual acuity. Whitney U test was operated in stereo vision comparison. Chi-square test was applied in sex-distribution comparison and visual function questionnaire between two groups. Results: The uncorrected distance vision in MV1 group was (0.09±0.09), while it was (0.11±0.08) in MV2 group. The uncorrected intermediate vision in MV1 group was (0.27±0.25), and it was (0.30±0.22) in MV2 group. There were no significant difference between two groups in bilateral uncorrected distance vision (t=1.62, P=0.264, LogMAR), intermediate (t=- 0.23, P=0.876, LogMAR). However, there was significant difference between two groups in uncorrected near vision (t=2.38, P=0.021, LogMAR). It was (0.06±0.06) in MV1 group and (0.02±0.07) in MV2 group. Moreover, near stereo vision was better in MV1 group than MV2 group (Z=- 1.29, P=0.031). On the questionnaire, all patients in two groups had no significant difference in their daily lives discomfort (χ(2)=0.10, P=0.756). In MV2 group, there were 2 patients complained obstacles while walking stairs dimly. In MV1 group, there were 3 patients had to wear low degrees of presbyopic glasses when they were on near work. Percentage of patients spectacle independence was less than 90% in MV1 groups. In MV2 group, one case needed low degrees of myopic glasses when he was on intermediate computer work and playing table games. Conclusion: Different near addition has similar advantages to different patients on spectacle independence, satisfaction and visual function after cataract surgery. (Chin J Ophthalmol,2017,53: 451-454).

[Establishment of macrophage model of iron overload in vitro and the injury induced by oxidative stress on macrophage with iron overload]

OBJECTIVE

To establish macrophage iron overload model in vitro by co-culture macrophages with iron, and to explore the effect of iron overload on cell reactive oxygen species (ROS) and the impact of ROS on macrophages.

METHOD

Iron overload group were treated with different concentrations (0, 5, 10, 20, 40, 80 μmol/L respectively) of ferric ammonium citrate (FAC). The control group was the group of macrophages without FAC treatment. We detected the number and state of cells, metabolic activity, the change of phagocytosis, the levels of ROS and reactive nitrogen, and changes of related oxidative stress signaling pathways in different groups. Changes in the above indexes were detected after application of deferasirox (DFX) to remove iron and the antioxidant N -acetylcysteine (NAC) to clear excess oxidative stress.

RESULTS

(1)The levels of labile iron pool (LIP) in macrophages co-cultivated with iron was increased with the increase of iron concentration in a dose-dependent manner. The LIP levels was the highest in the macrophages treated with 80 μmol/L. (2)The increase of FAC concentration, the metabolic activity of macrophages in the 5 FAC-treated groups decreased to 51.58%, 40.98%, 16.23%, 3.46%, and 0.05% of the activity level of the control group (all P< 0.05). The group with the metabolic activity decreased to 16.23% (20 μmol/L) was selected as the iron overload group for the following experiments. (3)Compared with the control group, the number of macrophages in the iron overload group reduced to 32.80% (P<0.05), and the state of cells changed from adherence to partial suspension. The phagocytosis of macrophages in the iron overload group reduced to 20.40% of the control group (P<0.05). (4)Our further experiment showed that the levels of ROS and the activity nitrogen in the iron overload group increased by 7.71-and 1.45-fold compared with the control group (both P<0.05). The RT-PCR showed up-regulated mRNA expression of genes related with ROS production, i. e. nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX 4) gene related with ROS production and inducible nitric oxide synthase (iNOS) gene related with reactive nitrogen production, down-regulated mRNA expression of glutathione peroxidase 1 (GPX1) gene which participated in ROS clearance. Moreover, mRNA expression of phosphatidylinositol-3-kinase (PI3K) gene involved in oxidative stress signaling pathway in the iron overload group was up-regulated, while fork head protein O3 (FOXO3) which regulated oxidative stress through negative feedback showed a down-regulation level of mRNA expression compared with the control group. (5)After iron chelation and antioxidant treatment, the above-mentioned damage in the iron overload group were partially reversed.

CONCLUSIONS

The damages of iron overload on macrophages may be mediated by inducing oxidative stress and activating oxidative stress signaling pathways. Our established model provides a method to explore the mechanism of iron overload on macrophage, and may shed some new light on possible therapeutic target in treating iron overload patients.

A crucial role of SUMOylation in modulating Sirt6 deacetylation of H3 at lysine 56 and its tumor suppressive activity

Sirt6 is a histone deacetylase with NAD(+)-dependent activity. Sirt6 has been shown as a tumor suppressor partially via inhibiting the expression of c-Myc target genes and ribosome biogenesis. However, how to regulate Sirt6 activity is largely unknown. In this study, we identify that Sirt6 can be modified by small ubiquitin-like modifier. Sirt6 SUMOylation deficiency specifically decreases its deacetylation of H3K56 but not H3K9 in vivo. Mechanistically, we find that SUMOylation deficiency decreases Sirt6 binding with c-Myc, decreasing Sirt6 occupancy on the locus of c-Myc target genes. Therefore, Sirt6 SUMOylation deficiency reduces its deacetylation of H3k56 and its repression of c-Myc target genes. Moreover, Sirt6 SUMOylation deficiency reduces its suppression of cell proliferation and tumorigenesis. Thus, these results reveal that SUMOylation has an important role in regulation of Sirt6 deacetylation on H3K56, as well as its tumor suppressive activity.