The UBE2F-CRL5ASB11-DIRAS2 axis is an oncogene and tumor suppressor cascade in pancreatic cancer cells

UBE2F, a neddylation E2, neddylates CUL5 to activate cullin-RING ligase-5, upon coupling with neddylation E3 RBX2/SAG. Whether and how UBE2F controls pancreatic tumorigenesis is previously unknown. Here, we showed that UBE2F is essential for the growth of human pancreatic cancer cells with KRAS mutation. In the mouse KrasG12D pancreatic ductal adenocarcinoma (PDAC) model, Ube2f deletion suppresses cerulein-induced pancreatitis, and progression of acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia. Mechanistically, Ube2f deletion inactivates the Mapk-c-Myc signals via blocking ubiquitylation of Diras2, a substrate of CRL5Asb11 E3 ligase. Biologically, DIRAS2 suppresses growth and survival of human pancreatic cancer cells harboring mutant KRAS, and Diras2 deletion largely rescues the phenotypes induced by Ube2f deletion. Collectively, Ube2f or Diras2 plays a tumor-promoting or tumor-suppressive role in the mouse KrasG12D PDAC model, respectively. The UBE2F-CRL5ASB11 axis could serve as a valid target for pancreatic cancer, whereas the levels of UBE2F or DIRAS2 may serve as prognostic biomarkers for PDAC patients.

MRI-based bone marrow radiomics for predicting cytogenetic abnormalities in multiple myeloma

AIM

To develop a radiomics signature applied to magnetic resonance imaging (MRI)-images to predict cytogenetic abnormalities in multiple myeloma (MM).

MATERIALS AND METHODS

Patients with newly diagnosed MM were enrolled retrospectively from March 2019 to September 2022. They were categorised into the high-risk cytogenetics (HRC) group and standard-risk cytogenetics (SRC) group. The patients were allocated randomly at a ratio of 7:3 into training and validation cohorts. Volumes of interest (VOI) was drawn manually on fat suppression T2-weighted imaging (FS-T2WI) and copied to the same location of the T1-weighted imaging (T1WI) sequence. Radiomics features were extracted from two sequences and selected by reproducibility and redundant analysis. The least absolute shrinkage selection operation (LASSO) algorithm was applied to build the radiomics signatures. The performance of the radiomics signatures to distinguish HRC with SRC was evaluated by ROC curves. The area under the curve (AUC), specificity, and sensitivity were also calculated.

RESULTS

A total of 105 MM patients were enrolled in this study. The four and 11 most significant and relevant features were selected separately from T1WI and FS-T2WI sequences to build the radiomics signatures based on the training cohort. Compared to the T1WI sequence, the radiomics signature based on the FS-T2WI sequence achieved better performance with AUCs of 0.896 and 0.729 in the training and validation cohorts respectively. A sensitivity of 0.833, specificity of 0.667, and Youden index of 0.500 were achieved for the FS-T2WI radiomics signature in the validation cohort.

CONCLUSIONS

The radiomics signature based on MRI provides a non-invasive and convenient tool to predict cytogenetic abnormalities in MM patients.

[Pathogenic characteristics and influence factors of bloodstream infection-induced severe sepsis in pediatric intensive care unit]

Objective: To summarize the pathogenic characteristics of bloodstream infection (BSI)-induced severe sepsis and analyze the influence factors in pediatric intensive care unit (PICU). Methods: Pediatric patients who were diagnosed with severe sepsis caused by BSI in the PICU of Children's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine from January 2016 to December 2021 were retrospectively selected and divided into survival group and death group according to their discharge outcomes. Clinical characteristics, laboratory parameters, pathogenic characteristics and drug resistance of the patients were collected. The characteristics of pathogens, clinical and laboratory indicators were summarized, and the influencing factors of death in children with severe sepsis caused by BSI were analyzed based on binary multivariate logistic regression. Results: A total of 132 patients, aged [M (Q1, Q3)] 36 (10, 119) months, with BSI-induced severe sepsis were enrolled in this study, including 81 males and 51 females. There were 38 cases aged 36 (15, 120) months in the death group, including 23 males and 15 females. There were 94 cases, aged 36 (8, 108) months, in the survival group, including 58 males and 36 females. A total of 132 strains of pathogens were isolated, including 87 strains (65.9%) of Gram-negative bacteria. The top 5 pathogens were Klebsiella pneumoniae (24 cases, 18.2%), Escherichia coli (17 cases, 12.9%), Acinetobacter baumannii (13 cases, 9.8%), Pseudomonas aeruginosa (10 cases, 7.6%) and Staphylococcus aureus (10 cases, 7.6%). The proportion of multi-drug resistant bacteria in hospital-acquired BSI was higher than that in community-acquired BSI [52.9% (36/68) vs 15.6% (10/64), P=0.001]. The proportions of community-acquired infection were 58.5% (55/94) and 23.7% (9/38) in the survival and death groups, respectively, the difference was statistically significant (P<0.001). The proportion of central venous catheter insertion before bloodstream infection in the death group was higher than that in the survival group [63.2% (24/38) vs 42.6% (40/94), P=0.034]. According to the binary multivariate logistic regression analysis, hospital-acquired infection (OR=4.80, 95%CI: 1.825-12.621, P=0.001), absolute neutrophil count (ANC) (OR=0.93, 95%CI: 0.863-0.993, P=0.030) and decreased albumin (OR=0.89, 95%CI: 0.817-0.977, P=0.014) were risk factors for death. Conclusions: The common pathogen of BSI-induced severe sepsis in PICU is Gram-negative bacteria. The proportion of multi-drug resistant organisms of BSI obtained in hospitals is high. Children with severe sepsis due to BSI with nosocomial acquired infection, ANC and decreased albumin have a high risk of death.

Intraperitoneal PD-1 monoclonal antibody for the treatment of advanced primary liver cancer with malignant ascites: a single-arm, single-center, phase Ib trial

BACKGROUND

Advanced primary liver cancer patients with malignant ascites have a poor prognosis and lack effective treatment plans. This phase Ib study aims to explore the safety and clinical efficacy of intraperitoneal anti-programmed cell death protein 1 (PD-1) antibody in these patients.

PATIENTS AND METHODS

Patients received sintilimab 100 mg intraperitoneally plus best supportive care on days 1, 8, and 15 in three cycles of 4 weeks. The course was repeated every 28 days until intolerable toxicity had developed or disease progression. The primary endpoint was safety, while the secondary endpoints were objective response rate (ORR), ascites control rate (ACR), and overall survival (OS).

RESULTS

From February 2021 through November 2022, a total of 21 patients (14 hepatocellular carcinoma and 7 cholangiocarcinoma) were enrolled to receive intraperitoneal sintilimab. Twelve patients had adverse events (AEs). The most common grade 3 AEs were fatigue, rash, and abdominal pain. No grade ≥4 AEs occurred in any patients. ORR was only evaluated in 13 patients, including partial response in 4, stable disease in 7, and progressive disease in 2. A reduction in the median maximum diameter of the tumor after treatment was observed; however, there was no statistical significance among patients. The objective remission rate of ascites was 43.75%, and the median OS for all 21 patients was 17.6 weeks.

CONCLUSIONS

This exploratory study represents the first trial to demonstrate the safety and clinical efficacy of intraperitoneal anti-PD-1 antibody administration. No unexpected safety concerns were identified. A large, multicenter, prospective study is needed to confirm the promising clinical efficacy.

Discriminating minimal residual disease status in multiple myeloma based on MRI: utility of radiomics and comparison of machine-learning methods

AIM

To explore the possibility of discriminating minimal residual disease (MRD) status in multiple myeloma (MM) based on magnetic resonance imaging (MRI) and identify optimal machine-learning methods to optimise the clinical treatment regimen.

MATERIALS AND METHODS

A total of 83 patients were analysed retrospectively. They were divided randomly into training and validation cohorts. The regions of interest were segmented and radiomics features were extracted and analysed on two sequences, including T1-weighted imaging (WI) and fat saturated (FS)-T2WI, and then radiomics models were built in the training cohort and evaluated in the validation cohort. Clinical characteristics were calculated to build a traditional model. A combined model was also built using the clinical characteristics and radiomics features. Classification accuracy was assessed using area under the curve (AUC) and F1 score.

RESULTS

In the training cohort, only the bone marrow (BM) infiltrate ratio (p=0.005) was retained after univariate and multivariable logistic regression analysis. In T1WI, the linear support vector machine (SVM) achieved the best performance compared to other classifiers, with AUCs of 0.811 and 0.708 and F1 scores of 0.792 and 0.696 in the training and validation cohorts, respectively. Similarly, in FS-T2WI sequence, linear SVM achieved the best performance with AUCs of 0.833 and 0.800 and F1 score of 0.833 and 0.800. The combined model constructed by the FS-T2WI-linear SVM and BM infiltrate ratio outperformed the traditional model (p=0.050 and 0.012, Delong test), but showed no significant difference compared with the radiomics model (p=0.798 and 0.855).

CONCLUSION

The linear SVM-based machine-learning method can offer a non-invasive tool for discriminating MRD status in MM.

The UBE2C/CDH1/DEPTOR axis is an oncogene and tumor suppressor cascade in lung cancer cells

Ubiquitin-conjugating enzyme E2C (UBE2C) mediates ubiquitylation chain formation via the K11 linkage. While previous in vitro studies showed that UBE2C plays a growth-promoting role in cancer cell lines, the underlying mechanism remains elusive. Still unknown is whether and how UBE2C plays a promoting role in vivo. Here we report that UBE2C was indeed essential for growth and survival of lung cancer cells harboring Kras mutations, and UBE2C was required for KrasG12D-induced lung tumorigenesis, since Ube2c deletion significantly inhibited tumor formation and extended the lifespan of mice. Mechanistically, KrasG12D induced expression of UBE2C, which coupled with APC/CCDH1 E3 ligase to promote ubiquitylation and degradation of DEPTOR, leading to activation of mTORC signaling. Importantly, DEPTOR levels fluctuated during cell cycle progression in a manner dependent on UBE2C and CDH1, indicating their physiological connection. Finally, Deptor deletion fully rescued the tumor inhibitory effect of Ube2c deletion in the KrasG12D lung tumor model, indicating a causal role of Deptor. Taken together, our study shows that the UBE2C/CDH1/DEPTOR axis forms an oncogene and tumor suppressor cascade that regulates cell cycle progression and autophagy and validates UBE2C an attractive target for lung cancer associated with Kras mutations.

[Observation on the clinical outcomes of continued pregnancy following cesarean scar pregnancy in 55 women]

Objective: To observe the clinical outcomes of continued pregnancy in pregnant women with cesarean scar pregnancy (CSP). Methods: A retrospective analysis was performed on the pregnancy outcomes of 55 pregnant women who were diagnosed with CSP at the Second Affiliated Hospital of Army Medical University during the first trimester of pregnancy from August 1st, 2018 to October 31st, 2021 and strongly requested to continue the pregnancy. Results: Of the 55 pregnant women, 15 terminated the pregnancy in the first trimester, 1 underwent hysterotomy at 23 weeks of gestation due to cervical dilation, and 39 (71%, 39/55) continued pregnancy to the third trimester achieving live births via cesarean section. The gestational age of the 39 pregnant women delivered by cesarean section was 35⁺⁶ weeks (range: 28⁺⁵-39⁺² weeks), of whom 7 cases at 28⁺⁵-33⁺⁶ weeks, 20 cases at 34-36⁺⁶ weeks, and 12 cases at 37-39⁺² weeks. The results of pathological examination were normal placenta in 3 cases (8%, 3/39), placenta creta in 4 cases (10%, 4/39), placenta increta in 9 cases (23%, 9/39) and placenta percreta in 23 cases (59%, 23/39). Among the 36 pregnant women who were pathologically confirmed as placenta accreta spectrum disorders (PAS) after surgery, the last prenatal ultrasonography showed placenta previa in 27 cases (75%, 27/36) and not observed placenta previa in 9 cases. The median intraoperative blood loss, autologous blood transfusion, and allogeneic suspended red blood cell infusion of 39 pregnant women during cesarean section were 1 000 ml (300-3 500 ml), 300 ml (0-2 000 ml) and 400 ml (0-2 400 ml), respectively. The uterine preservation rate was 100% (39/39), and only 1 case received cystostomy due to intracystic hemorrhage. The birth weight of the newborn was 2 580 g (1 350-3 800 g), and 1 case of mild asphyxia. Conclusions: Pregnant women with CSP who continue pregnancy under close monitoring after adequate ultrasound evaluation and doctor-patient communication could achieve better maternal and infant outcomes, but pregnant women with CSP are highly likely to continue pregnancy and develop into PAS. Effective hemostasis means and multidisciplinary team cooperation are needed in perinatal period for ensuring maternal and fetal safety.

A Canine Surgical Model of Stroke by Minimally Invasive Occlusion of the Proximal Middle Cerebral Artery

In this study, a model of ischemic stroke by surgical proximal middle cerebral artery (MCA) occlusion was developed on 10 beagle dogs. The advantages of this model are the transtemporal approach and a minimally invasive surgical procedure. Dogs were randomly assigned to two groups: sham-operated (proximal MCA exposure without occlusion) and experimental (permanent proximal MCA occlusion) groups. Different evaluation methods were used to assess the consequences of MCA occlusion in dogs, including neurobehavioral tests, MRI, and immunohistochemical staining. Clear signs of cerebral infarction associated with the region supplied by MCA were confirmed and the model showed good repeatability and consistency. The model can serve as an appropriate large animal model to improve the translation of stroke therapeutics research from the laboratory to the clinical practice.

Association of aldehyde exposure with bone mineral density in the national health and nutrition examination survey (NHANES 2013-2014)

PURPOSE

The association between aldehyde exposure and bone health in humans remains unclear. This study was to evaluate the association of serum aldehydes with bone mineral density (BMD) and osteopenia/osteoporosis.

METHODS

We analyzed the US National Health and Nutrition Examination Survey cross-sectional data from 2013 to 2014. Weighted multivariate-adjusted linear regression and logistic regression models were used to assess the association between specific aldehydes and osteopenia/osteoporosis. Associations between aldehyde combinations and BMD were also evaluated using the restricted cubic spline (RCS) method.

RESULTS

Compared with men in the first tertile, those in the third tertile of propanaldehyde concentration were negatively associated with proximal femur and lumbar spine BMD. Significant inverse associations were observed between benzaldehyde exposure and trochanter BMD in women. Benzaldehyde increased the risk of osteopenia/osteoporosis 2.75-fold [95% confidence interval (CI) = 1.06, 7.11] in the highest tertile in women compared to the lowest tertile concentration. In males, the prevalence of total femur, femur neck, and trochanter osteopenia/osteoporosis was significantly higher in the highest versus the lowest tertile of propanaldehyde exposure, with odds ratios (ORs) of 6.84 (95% CI = 2.33, 20.04), 2.72 (95% CI = 1.18, 6.27), and 3.26 (95% CI = 1.25, 8.56), respectively. RCS regression also showed decreased BMD continuously with increasing serum mixed aldehyde levels.

CONCLUSIONS

Serum aldehyde concentrations were associated with low BMD and high osteopenia/osteoporosis risk in adults, with propanaldehyde and benzaldehyde being the most critical. Co-exposure to aldehyde combinations was negatively correlated with BMD.

A small molecule inhibitor of the UBE2F-CRL5 axis induces apoptosis and radiosensitization in lung cancer

Protein neddylation is catalyzed by a neddylation activating enzyme (NAE, E1), an E2 conjugating enzyme, and an E3 ligase. In various types of human cancers, the neddylation pathway is abnormally activated. Our previous study validated that the neddylation E2 UBE2F is a promising therapeutic target in lung cancer. Although the NAE inhibitor MLN4924/pevonedistat is currently under clinical investigation as an anti-cancer agent, there are no small molecules available that selectively target UBE2F. Here, we report, for the first time, the discovery, via structure-based virtual screen and chemical optimization, of such a small molecule, designated as HA-9104. HA-9104 binds to UBE2F, reduces its protein levels, and consequently inhibits cullin-5 neddylation. Blockage of cullin-5 neddylation inactivates cullin-RING ligase-5 (CRL5) activity, leading to accumulation of the CRL5 substrate, NOXA, to induce apoptosis. Moreover, HA-9104 appears to form the DNA adduct via its 7-azaindole group to induce DNA damage and G2/M arrest. Biologically, HA-9104 effectively suppresses the growth and survival of lung cancer cells and confers radiosensitization in both in vitro cell culture and in vivo xenograft tumor models. In summary, we discovered a small molecule, designated HA-9104, that targets the UBE2F-CRL5 axis with anti-cancer activity alone or in combination with radiation.

PD-L1 induction via the MEK-JNK-AP1 axis by a neddylation inhibitor promotes cancer-associated immunosuppression

MLN4924 is a first-in-class small molecule inhibitor of NEDD8-activating enzyme (NAE), which is currently in several clinical trials for anti-cancer applications. However, MLN4924 also showed some off-target effects with potential to promote the growth of cancer cells which counteracts its anticancer activity. In this study, we found that MLN4924 increases the levels of PD-L1 mRNA and protein in dose- and time-dependent manners. Mechanistic study showed that this MLN4924 effect is largely independent of neddylation inactivation, but is due to activation of both ERK and JNK signals, leading to AP-1 activation, which is blocked by the small molecule inhibitors of MEK and JNK, respectively. Biologically, MLN4924 attenuates T cell killing in a co-culture model due to PD-L1 upregulation, which can be, at least in part, abrogated by either MEK inhibitor or anti-PD-L1 antibody. In an in vivo BALB/c mouse xenograft tumor model, while MLN4924 alone had no effect, combination with either MEK inhibitor or anti-PD-L1 antibody enhanced the suppression of tumor growth. Taken together, our study provides a sound rationale for effective anticancer therapy in combination of anti-PD-L1 antibody or MEK inhibitor with MLN4924 to overcome the side-effect of immunosuppression by MLN4924 via PD-L1 induction.

The Cross Talk Between p53 and mTOR Pathways in Response to Physiological and Genotoxic Stresses

The tumor suppressor p53 is activated upon multiple cellular stresses, including DNA damage, oncogene activation, ribosomal stress, and hypoxia, to induce cell cycle arrest, apoptosis, and senescence. Mammalian target of rapamycin (mTOR), an evolutionarily conserved serine/threonine protein kinase, serves as a central regulator of cell growth, proliferation, and survival by coordinating nutrients, energy, growth factors, and oxygen levels. p53 dysfunction and mTOR pathway hyperactivation are hallmarks of human cancer. The balance between response to stresses or commitment to cell proliferation and survival is governed by various regulatory loops between the p53 and mTOR pathways. In this review, we first briefly introduce the tumor suppressor p53 and then describe the upstream regulators and downstream effectors of the mTOR pathway. Next, we discuss the role of p53 in regulating the mTOR pathway through its transcriptional and non-transcriptional effects. We further describe the complicated role of the mTOR pathway in modulating p53 activity. Finally, we discuss the current knowledge and future perspectives on the coordinated regulation of the p53 and mTOR pathways.

Malignant acanthosis nigricans and diseases with extensive oral papillary hyperplasia

Oral papillary lesions represent a variety of developmental and neoplastic conditions. Early diagnoses of different papillary lesions are challenging for oral medicine specialists. Malignant acanthosis nigricans (MAN) is a rare cutaneous disorder and a potential marker of underlying hidden tumours. It is characterized by papillary lesions that always involve the oral mucosa. In oral medicine specialities, MAN is not well understood. When the early signs of MAN are extensive oral lesions and slight cutaneous pigmentation without obvious florid cutaneous papillomatosis, the diagnosis can be incorrect or delayed. Oral medicine specialists should ask affected patients to provide details of their medical history and conduct a timely systemic examination.

Transcriptome analysis of oviduct in laying ducks under different stocking densities

1. High stocking densities can lead to animal stress responses and lead to changes in bird behaviour, egg production and the fertility of laying birds. The oviduct plays a crucial role during the process of laying eggs. Therefore, it is essential to know how high stocking density affects oviduct function.2. In this study, a total of 2,115 differentially expressed genes (DEGs) were identified in duck oviduct tissues between different stocking density groups. These genes are mainly enriched in membrane components, calcium ion binding, cytokine-cytokine receptor interaction and focal adhesion. These pathways were closely related to the formation of eggs. This indicated that secretion and material transport functions of the oviduct are affected under high-density stocking. Further analysis showed that a total of 408 genes related to the transportation process were expressed in the oviduct, of which 96 genes were differentially expressed (LogFC≥1, P < 0.05). Forty-two of these DEGs belonged to the solute carrier family. The data showed that the expression of 31 transcripts was different between the two density groups. Expression of KCNJ15, SLC26A8, and TRPM5 was only seen in the high-density group (8/m²), while ATP13A3 and KCNIP2 were only expressed in the low-density group (4/m²).3. Consequently, high stocking density may affect the expression and splicing of genes related to molecular transport in the oviduct.

P90 ribosomal S6 kinase confers cancer cell survival by mediating checkpoint kinase 1 degradation in response to glucose stress

In solid tumors, cancer cells have devised multiple approaches to survival and proliferate in response to glucose starvation that is often observed in solid tumor microenvironments. However, the precise mechanisms are far less known. Herein, we report that glucose deprivation activates 90‐kDa ribosomal S6 kinase (p90 RSK), a highly conserved Ser/Thr kinase, and activated p90 RSK promotes cancer cell survival. Mechanistically, activated p90 RSK by glucose deprivation phosphorylates checkpoint kinase 1 (CHK1), a key transducer in checkpoint signaling pathways, at Ser280 and triggers CHK1 ubiquitination mediated by SCF^β‐TrCP ubiquitin ligase and proteasomal degradation, subsequently suppressing cancer cell apoptosis induced by glucose deprivation. Importantly, we identified an inverse correlation between p90 RSK activity and CHK1 levels within the solid tumor mass, with lower levels of CHK1 and higher activity of p90 RSK in the center of the tumor where low glucose concentrations are often observed. Thus, our study indicates that p90 RSK promotes CHK1 phosphorylation at Ser280 and its subsequent degradation, which allows cancer cells to escape from checkpoint signals under the stress of glucose deprivation, leading to cell survival and thus contributing to tumorigenesis.

DEPTOR inhibits lung tumorigenesis by inactivating the EGFR-mTOR signals

DEPTOR plays vital roles in the regulation of cell proliferation and survival by directly modulating the activity of mTORC1/2. However, the physiological role of DEPTOR in lung tumorigenesis, as well as its clinical significance, remains elusive. In this study, we revealed that decreased DEPTOR expression correlated with increased tumor size, poor differentiation, and worse survival in patients with lung cancer. DEPTOR depletion promoted cell proliferation, survival, migration, and invasion in human lung cancer cells. Mechanistically, DEPTOR bound to the kinase domain of EGFR via its PDZ domain to inactivate EGFR signal. Thus, DEPTOR depletion not only directly activated mTORC1/2, but also relieved the inhibition of EGFR to subsequently activate mTOR signals, leading to the induction of cell proliferation and survival. Additionally, activated EGFR-mTOR signals upregulated the expression of ZEB1 and SLUG to induce epithelial-mesenchymal transition, resulting in enhanced migration and invasion. Importantly, Deptor deletion accelerated Kras^G12D;p53^fl/fl-induced lung tumorigenesis and shortened mouse life span via the activation of EGFR-mTOR signals. Collectively, our study demonstrated that DEPTOR acts as a tumor suppressor in lung tumorigenesis, and its reduction may advance the progression of human lung cancer.

The Negative Cross-Talk between SAG/RBX2/ROC2 and APC/C E3 Ligases in Regulation of Cell Cycle Progression and Drug Resistance

Anaphase-promoting complex/cyclosome (APC/C) is a well-characterized E3 ligase that couples with UBE2C and UBE2S E2s for substrate ubiquitylation by the K11 linkage. Our recent data show that SAG/RBX2/ROC2, a RING component of Cullin-RING E3 ligase, also complexes with these E2s for K11-linked substrate polyubiquitylation. Whether these two E3s cross-talk with each other was previously unknown. Here, we report that SAG competes with APC2 for UBE2C/UBE2S binding to act as a potential endogenous inhibitor of APC/C, thereby regulating the G2-to-M progression. As such, SAG knockdown triggers premature activation of APC/C, leading to mitotic slippage and resistance to anti-microtubule drugs. On the other hand, SAG itself is a substrate of APC/C^CDH1 for targeted degradation at the G1 phase. The degradation-resistant mutant of SAG-R98A/L101A accelerates the G1-to-S progression. Our study reveals that the negative cross-talk between SAG and APC/C is likely a mechanism to ensure the fidelity of cell cycle progression.

Zhang et al. provide a mechanistic insight of how negative cross-talk between E3 ligases SAG and APC/C ensures proper cell cycle progression. SAG knockdown prematurely activates APC/C to promote mitotic progression and trigger anti-microtubule drugs resistance, whereas SAG degradation by APC/C^CDH1 mainly occurs in G1 phase for proper G1-to-S transition.

[Establishment of naive Bayes classifier-based risk prediction model for chemotherapyinduced nausea and vomiting]

OBJECTIVE

To establish a risk prediction model of chemotherapy-induced nausea and vomiting based on naive Bayes classifier.

OBJECTIVE

We collected the basic information, treatment protocols and follow-up data from 300 patients receiving chemotherapy in the Oncology Department of Second Xiangya Hospital from July to September, 2020. Correlation analysis was carried out between the potential factors related to nausea and vomiting in the treatment plan and the individual characteristics of the patients. For the two characteristics with a correlation coefficient greater than 0.8, their contribution to the area under curve (AUC) was calculated, and the characteristic with a smaller contribution was removed. The naive Bayes classifier in the machine learning library scikit-learn was used as the prediction model of chemotherapy-induced nausea and vomiting, and 10-fold stratified-shuffled-split cross-validation was used to obtain the final result of the model. The machine learning model was trained using 70% of the samples, and 30% of the samples were used as the test set to assess the performance of the model.

OBJECTIVE

The sensitivity of the model for predicting the risk of nausea and vomiting due to acute chemotherapy was 0.83±0.04 (95%CI: 0.80-0.86) with a specificity of 0.45±0.03 (95%CI: 0.42-0.47) and an AUC of 0.72±0.04 (95% CI: 0.69-0.75). The sensitivity of the model for predicting the risk of delayed chemotherapy-induced nausea and vomiting was 0.84±0.01 (95%CI: 0.83-0.86) with a specificity of 0.48±0.03 (95%CI: 0.45-0.52) and an AUC of 0.74±0.02 (95%CI: 0.72-0.77).

OBJECTIVE

The naive Bayes classifier model has a good performance in predicting the risk of chemotherapy-induced nausea and vomiting in Chinese cancer patients.

DEPTOR stabilizes ErbB2 to promote the proliferation and survival of ErbB2-positive breast cancer cells

Rationale: Dysregulation of the PI3K/AKT/mTOR pathway occurs frequently in cancers, providing an attractive therapeutic target for anticancer treatments. DEPTOR plays essential roles in regulation of cell proliferation and survival by directly modulating mTOR activity. However, whether DEPTOR regulates the growth of ErbB2-positive breast cancer cells remains unknown.

Methods: DEPTOR expression was determined by TCGA data analysis and immunohistochemistry of human breast tissue microarrays. The membrane localization of DEPTOR was demonstrated by immunofluorescence and subcellular fractionation. The interaction of DEPTOR with ErbB2 was determined by immunoprecipitation. Furthermore, the biological significance of this interaction was assessed by ATPlite cell growth, clonogenic survival, and flow cytometry-based apoptosis assays.

Results: DEPTOR promoted the proliferation and survival of ErbB2-positive breast cancer cells by directly interacting with and stabilizing ErbB2. Specifically, DEPTOR translocates to cell membrane and interacts with ErbB2 to disrupt ErbB2 polyubiquitination and degradation promoted by β-TrCP, an E3 ubiquitin ligase. DEPTOR knockdown destabilizes ErbB2 by shortening its protein half-life to inactivate ErbB2-PI3K-AKT-mTOR signaling, leading to the suppression of cell proliferation and survival by inducing apoptosis. Ectopic expression of a constitutively active ErbB2 mutant completely rescued the reduction in cell proliferation and survival by DEPTOR knockdown. Importantly, DEPTOR expression is increased in human breast cancer tissues and its overexpression correlates with poor patient survival. Moreover, DEPTOR is located on the cell membrane in ErbB2-positive breast cancer tissues, but not in tumor-adjacent normal tissues, indicating that DEPTOR may contribute to the oncogenic characteristics of ErbB2.

Conclusions: Our study reveals a novel mechanism by which DEPTOR promotes breast cancer cell proliferation and survival by stabilizing ErbB2.

Nuclear ErbB2 represses DEPTOR transcription to inhibit autophagy in breast cancer cells

ErbB2, a classical receptor tyrosine kinase, is frequently overexpressed in breast cancer cells. Although the role of ErbB2 in the transmission of extracellular signals to intracellular matrix has been widely studied, the functions of nuclear ErbB2 remain largely elusive. Here, we report a novel function of nuclear ErbB2 in repressing the transcription of DEPTOR, a direct inhibitor of mTOR. Nuclear ErbB2 directly binds to the consensus binding sequence in the DEPTOR promoter to repress its transcription. The kinase activity of ErbB2 is required for its nuclear translocation and transcriptional repression of DEPTOR. Moreover, the repressed DEPTOR by nuclear ErbB2 inhibits the induction of autophagy by activating mTORC1. Thus, our study reveals a novel mechanism for autophagy regulation by functional ErbB2, which translocates to the nucleus and acts as a transcriptional regulator to suppress DEPTOR transcription, leading to activation of the PI3K/AKT/mTOR pathway to inhibit autophagy.

FBXW7 Confers Radiation Survival by Targeting p53 for Degradation

The tumor suppressor p53 plays a critical role in integrating a wide variety of stress responses. Therefore, p53 levels are precisely regulated by multiple ubiquitin ligases. In this study, we report that FBXW7, a substrate recognition component of the SKP1-CUL1-F-box (SCF) E3 ligase, interacts with and targets p53 for polyubiquitination and proteasomal degradation after exposure to ionizing radiation or etoposide. Mechanistically, DNA damage activates ATM to phosphorylate p53 on Ser33 and Ser37, which facilitates the FBXW7 binding and subsequent p53 degradation by SCF^FBXW7. Inactivation of ATM or SCF^FBXW7 by small molecular inhibitors or genetic knockdown/knockout approaches extends the p53 protein half-life upon DNA damage in an MDM2-independent manner. Biologically, FBXW7 inactivation sensitizes cancer cells to radiation or etoposide by stabilizing p53 to induce cell-cycle arrest and apoptosis. Taken together, our study elucidates a mechanism by which FBXW7 confers cancer cell survival during radiotherapy or chemotherapy via p53 targeting.

DEPTOR is a direct p53 target that suppresses cell growth and chemosensitivity

DEP-domain containing mTOR-interacting protein (DEPTOR), a natural mTOR inhibitor, has essential roles in several processes, including cell growth, metabolism, apoptosis, and immunity. DEPTOR expression has been shown to be diversely controlled at transcriptional levels in cell- and context-specific manners. However, whether there is a general mechanism for the regulation of DEPTOR expression remains largely unknown. Here, we report that DEPTOR is a downstream target of the tumor suppressor, p53, whose activity is positively correlated with DEPTOR expression both in vitro in cell cultures and in vivo in mouse tissues. Mechanistically, p53 directly binds to the DEPTOR promoter and transactivates its expression. Depletion of the p53-binding site on the DEPTOR promoter by CRISPR-Cas9 technology decreases DEPTOR expression and promotes cell proliferation and survival by activating AKT signaling. Importantly, inhibition of AKT by small molecular inhibitors or genetic knockdown abrogates the induction of cell growth and survival induced by deletion of the p53-binding region on the DEPTOR promoter. Furthermore, p53, upon activation by the genotoxic agent doxorubicin, induces DEPTOR expression, leading to cancer cell resistance to doxorubicin. Together, DEPTOR is a direct p53 downstream target and contributes to p53-mediated inhibition of cell proliferation, survival, and chemosensitivity.

The characteristics and roles of β-TrCP1/2 in carcinogenesis

β-transducin repeat-containing protein (β-TrCP), one of the well-characterized F-box proteins, acts as a substrate receptor and constitutes an active SCF^β-TrCP E3 ligase with a scaffold protein CUL1, a RING protein RBX1, and an adaptor protein SKP1. β-TrCP plays a critical role in the regulation of various physiological and pathological processes, including signal transduction, cell cycle progression, cell migration, DNA damage response, and tumorigenesis, by governing burgeoning amounts of key regulators for ubiquitination and proteasomal degradation. Given that a variety of β-TrCP substrates are well-known oncoproteins and tumor suppressors, and dysregulation of β-TrCP is frequently identified in human cancers, β-TrCP plays a vital role in carcinogenesis. In this review, we first briefly introduce the characteristics of β-TrCP1, β-TrCP2, and SCF^β-TrCP ubiquitin ligase, and then discuss SCF^β-TrCP ubiquitin ligase regulated biological processes by targeting its substrates for degradation. Moreover, we summarize the regulation of β-TrCP1 and β-TrCP2 at multiple layers and further discuss the various roles of β-TrCP1 and β-TrCP2 in human cancer, functioning as either an oncoprotein or a tumor suppressor in a manner dependent of cellular context. Finally, we provide novel insights for future perspectives on the potential of targeting β-TrCP1 and β-TrCP2 for cancer therapy.

Inactivation of ribosomal protein S27-like impairs DNA interstrand cross-link repair by destabilization of FANCD2 and FANCI

Ribosomal protein S27-like (RPS27L), an evolutionarily conserved ribosomal protein and a direct p53 target, plays an important role in maintenance of genome integrity. We have previously reported that RPS27L regulates radiation sensitivity via the MDM2-p53 and MDM2-MRN-ATM axes. Whether and how RPS27L modulates DNA interstrand cross-link (ICL) repair is unknown. Here we identified that RPS27L binds to FANCD2 and FANCI, two Fanconi anemia (FA) proteins functioning in ICL repair pathway. Upon RPS27L knockdown, the levels of FANCD2 and FANCI are reduced due to accelerated degradation via p62-mediated autophagy-lysosome pathway, which is abrogated by chloroquine (CQ) treatment or Beclin 1 knockdown. Biologically, RPS27L knockdown suppresses FANCD2 foci formation and impairs ICL repair upon exposure to ICL-inducing agent mitomycin C (MMC) in lung cancer cells. This effect of MMC sensitization can be partially reversed by CQ treatment. Together, our study shows that RPS27L positively regulates ICL repair by binding with FANCD2 and FANCI to prevent their degradation via autophagy-lysosome system.

Neddylation modification of ribosomal protein RPS27L or RPS27 by MDM2 or NEDP1 regulates cancer cell survival

Neddylation plays a distinct role in stabilization of a subset of ribosomal proteins. Whether the family of ribosomal proteins S27 (RPS27 and RPS27-like) is subjected to neddylation regulation with associated biological consequence is totally unknown. Here, we report that both family members are subjected to neddylation by MDM2 E3 ubiquitin ligase, and deneddylation by NEDP1. Blockage of neddylation with MLN4924, a small molecule inhibitor of neddylation-activating enzyme, destabilizes RPS27L and RPS27 by shortening their protein half-lives. Biologically, knockdown of RPS27L and RPS27 sensitizes, whereas ectopic expression of RPS27L and RPS27 desensitizes cancer cells to MLN4924-induced apoptosis. Taken together, our study demonstrates that neddylation stabilizes RPS27L and RPS27 to confer the survival of cancer cells.

Small RNA sequencing reveals miRNAs important for hypoxic adaptation in the Tibetan chicken

1. The Tibetan chicken, which is an indigenous breed living on the Tibetan Plateau, exhibits hypoxic adaptations to its high-altitude environment. However, the molecular mechanism behind this hypoxic adaptation is still unclear. This study aimed to investigate differentially expressed miRNAs involved in hypoxic adaptation through high-throughput RNA sequencing. 2. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to verify the differentially expressed miRNAs and their target genes in chicken embryonic heart tissues and fibroblasts. Luciferase reporter assays were performed to confirm the relationship between miRNAs and target genes. 3. The study identified 37 differentially expressed miRNAs in Tibetan chicken embryonic heart tissues, including 20 up- and 17 down-regulated miRNAs, compared to those found in lowland chickens. Differentially expressed miRNAs were mainly involved in biological processes, such as cell cycle arrest, toll-like receptor signalling pathways, and I-kappa B kinase/NF-kappa B signalling. The data showed that gga-miR-34 c-5p was significantly upregulated in Tibetan chicken tissues and hypoxic fibroblasts, while EHHADH, a target gene of gga-miR-34 c-5p, was downregulated. Moreover, gga-miR-34 c-5p dramatically decreased the luciferase activity of the wild EHHADH, whereas no effect on the mutational EHHADH was found. 4. This study identified miRNA expression profiles in the Tibetan chicken and suggested that miR-34 c-5p acts as a novel miRNA associated with hypoxic adaptation. This facilitates the understanding of molecular mechanisms that underlie long-term exposure to hypoxia.

[Effect of pedicled thoracodorsal artery perforator flap on the repair of moderate to severe axillary scar contracture deformity]

Objective: To investigate the effect of pedicled thoracodorsal artery perforator (TDAP) flap on the repair of axillary moderate to severe scar contracture deformity. Methods: From January 2012 to January 2017, 29 patients with axillary moderate to severe scar contracture deformity were admitted to the the Second Xiangya Hospital of Central South University, including 18 females and 11 males, aged 14-42 years. There were 3 patients with cicatricial contracture deformity of bilateral axillas and 26 patients with cicatricial contracture deformity of unilateral axilla. After relevant preoperative examinations were completed and basic diseases were controlled, axillary scar was removed or released under the anesthesia of endotracheal intubation. The areas of wounds ranged from 7.5 cm×5.0 cm to 21.0 cm×8.5 cm after the operation. The pedicled TDAP flaps were used to repair the defects, which were thinned based on demand of the recipient sites before being transferred. The areas of flaps ranged from 9.0 cm×6.0 cm to 22.0 cm×10.0 cm. The donor sites were sutured directly. The status of thinned flaps, the survival of flaps after the operation and during follow-up, and the shoulder joint function during follow-up were observed. Results: Thirty-two pedicled TDAP flaps were harvested for repairing the defects. Among them, 14 flaps were transferred directly without thinning and the thickness of the flaps ranged from 9.0 mm to 15.0 mm, with average thickness of 13.6 mm.While the other 18 flaps were thinned, and the thickness of the thinned flaps ranged from 5.0 mm to 8.0 mm, with average thickness of 7.5 mm. The distal parts of 3 flaps in 3 patients showed small size of blackening or necrosis within 72 hours after the operation, and 2 of them were thinned and the other one was not. Finally, the 3 flaps were healed after hyperbaric oxygen therapy, dressing change, or other treatments. One flap occurred vein congestion 8 hours after the operation caused by pressure on the pedicle, and the color of the flap turned back to normal after the pressure was relieved. The rest of the flaps survived well. All the patients were followed up for 9 to 36 months, with an average of 18 months. All the flaps survived well, the color of the flaps was nearly the same as the recipient sites, and none of the flaps developed obvious contraction. The shoulder joint function of all patients was significantly improved compared with that before operation, with abduction angles of shoulder joints ranged from 90.0-145.0°, with an average of 130.0°. Conclusions: Pedicled TDAP flap is an relatively ideal choice for the repair of moderate to severe axillary scar contracture deformity, and better results will be achieved if the flaps are thinned to a appropriate thickness according to the condition of axillary defects.

Cullin-RING Ligase 5: Functional characterization and its role in human cancers

Cullin-RING ligase 5 (CRL5) is a multi-protein complex and consists of a scaffold protien cullin 5, a RING protein RBX2 (also known as ROC2 or SAG), adaptor proteins Elongin B/C, and a substrate receptor protein SOCS. Through targeting a variety of substrates for proteasomal degradation or modulating various protein-protein interactions, CRL5 is involved in regulation of many biological processes, such as cytokine signal transduction, inflammation, viral infection, and oncogenesis. As many substrates of CRL5 are well-known oncoproteins or tumor suppressors, abnormal regulation of CRL5 is commonly found in human cancers. In this review, we first briefly introduce each of CRL5 components, and then discuss the biological processes regulated by four members of SOCS-box-containing substrate receptor family through substrate degradation. We next describe how CRL5 is hijacked by a variety of viral proteins to degrade host anti-viral proteins, which facilitates virus infection. We further discuss the regulation of CUL5 and its various roles in human cancers, acting as either a tumor suppressor or an oncoprotein in a context-dependent manner. Finally, we propose novel insights for future perspectives on the validation of cullin5 and other CRL5 components as potential targets, and possible targeting strategies to discover CRL5 inhibitors for anti-cancer and anti-virus therapies.

[The value of analysis of quantitative radiomics based on DTI in predicting astrocytoma IDH1 mutation]

Objective: Non-invasive prediction of IDH1 mutations by establishing a quantitative radiographic model based on DTI-based whole-tumor texture analysis. Methods: Preoperative MRI images of patients with surgically confirmed astrocytoma were collected in the First Affiliated Hospital of Soochow University from February 2016 to June 2019, including T(1)WI, T(2)WI, DTI, and T(1)-contrast enhancement images.A total of 38 patients were included, consisting of 12 mutants and 26 wilds, 20 males and 18 females, the average age was (49±15) years old.The ROIs were drawn on each level of the T(2)WI image using MaZda software and copied to the ADC and FA maps to extract texture feature parameters. The LASSO regression was used to determine the best radiomics features, radiological scores were calculated, and binary Logistic regression was used to construct a prediction model, then the ROC curve was used to analyze the diagnostic efficiency and the calibration curve was used to evaluate model prediction performance. Results: The four most valuable radiomics features were determined by LASSO regression, and then the radiomics scores and Logistic regression models of each patient were established. The radiomics scores of the wild and mutant groups were 2.3±0.3 and 1.8±0.4. There were significant differences between the groups (P<0.05). The ROC curve analysis showed an AUC of 0.837 with sensitivity and specificity of 91.7% and 61.5%, respectively. The Logistic regression model had good predictive performance with AUC of 0.907, sensitivity and specificity of 91.7% and 84.6%. Conclusions: DTI-based whole tumor radiomics model is benefit for predicting astrocytoma IDH1 mutations.

The FBXW7-SHOC2-Raptor Axis Controls the Cross-Talks between the RAS-ERK and mTORC1 Signaling Pathways

FBXW7 is a tumor suppressive E3 ligase, whereas RAS-ERK and mechanistic target of rapamycin kinase (mTORC1) are two major oncogenic pathways. Whether and how FBXW7 regulates these two oncogenic pathways are unknown. Here, we showed that SHOC2, a RAS activator, is a FBXW7 substrate. Growth stimuli trigger SHOC2 phosphorylation on Thr⁵⁰⁷ by the mitogen-activated protein kinase (MAPK) signal, which facilitates FBXW7 binding for ubiquitylation and degradation. FBXW7-mediated SHOC2 degradation terminates the RAS-MAPK signals and inhibits proliferation. Furthermore, SHOC2 selectively binds to Raptor to competitively inhibit the Raptor-mTOR binding to inactivate mTORC1 and induce autophagy, whereas Raptor binding of SHOC2 inhibits the SHOC2-RAS binding to block the MAPK pathway and proliferation. Finally, SHOC2 is overexpressed in pancreatic cancer, which correlated with poor patient survival. SHOC2 mutations were found in lung cancer tissues with gain-of-function activity. Collectively, the SHOC2-Raptor interaction triggers negative cross-talk between RAS-ERK and mTORC1 pathways, whereas FBXW7 regulates both pathways by targeting SHOC2 for ubiquitylation and degradation.

Current updates on the role of reactive oxygen species in bladder cancer pathogenesis and therapeutics

Bladder cancer (BCa) is the fourth most common urological malignancy in the world, it has become the costliest cancer to manage due to its high rate of recurrence and lack of effective treatment modalities. As a natural byproduct of cellular metabolism, reactive oxygen species (ROS) have an important role in cell signaling and homeostasis. Although up-regulation of ROS is known to induce tumorigenesis, growing evidence suggests a number of agents that can selectively kill cancer cells through ROS induction. In particular, accumulation of ROS results in oxidative stress-induced apoptosis in cancer cells. So, ROS is a double-edged sword. A modest level of ROS is required for cancer cells to survive, whereas excessive levels kill them. This review summarizes the up-to-date findings of oxidative stress-regulated signaling pathways and transcription factors involved in the etiology and progression of BCa and explores the possible therapeutic implications of ROS regulators as therapeutic agents for BCa.

MicroRNAs in the Intestine: Role in Renewal, Homeostasis, and Inflammation

The mammalian intestine is not only an organ for food digestion and nutrient absorption but also an integral part of the immune and endocrine systems. The intestinal epithelium under stressful environments requires epithelial cells to rapidly elicit changes in gene expression patterns to regulate their survival, adapt to stress, and maintain epithelial homeostasis. Recently, miRNAs have emerged as a novel class of posttranscriptional gene regulators that are fundamentally involved in many aspects of intestinal epithelial differentiation, architecture, and barrier function. In this review, we highlight the critical roles of miRNAs in both the crypt-villus axis of cellular self-renewal and inflammation in the mammalian intestinal mucosa and their impact on the microbiota. We also discuss the functions of specific miRNAs within the intestine to better understand the cellular mechanisms that promote intestinal homeostasis, and the influence of dietary components in the regulation of endogenous miRNA in the study of nutrition and gene regulation in intestinal health.

The cross talk of two family members of β-TrCP in the regulation of cell autophagy and growth

β-transducin repeat-containing protein (β-TrCP), one of the best-characterized substrate recognition components of the SKP1-CUL1-F-box (SCF) E3 ligase, has two distinct paralogs, β-TrCP1 and β-TrCP2, expressed in mammals. Through governing the ubiquitination and degradation of numerous key regulators, β-TrCP1/2 regulates various cellular physiological and pathological processes. However, whether and how these two proteins cross talk and whether they regulate cell autophagy and proliferation in different manners is completely unknown. Herein, we report that β-TrCP1 and β-TrCP2 are the physiological substrates of SCF E3 ligase and target each other for degradation that is dependent on their β-TrCP degron sequences. Furthermore, glucose deprivation activates AMPK kinase to phosphorylate β-TrCP1 and promotes the subsequent ubiquitination and degradation of β-TrCP1 by β-TrCP2, but does not promote β-TrCP2 degradation by β-TrCP1. Finally, we found that β-TrCP2, not β-TrCP1, preferentially degrades DEPTOR and REDD1, the inhibitors of mTORC1, to activate mTORC1, leading to autophagy inhibition and cell growth. Thus, our study demonstrates that β-TrCP1 and β-TrCP2 mutually target each other for degradation and that β-TrCP2 acts as a dominant paralog in the regulation of cell autophagy and growth, which might be a promising anticancer target.

FBXW2 suppresses migration and invasion of lung cancer cells via promoting β-catenin ubiquitylation and degradation

FBXW2 inhibits proliferation of lung cancer cells by targeting SKP2 for degradation. Whether and how FBXW2 regulates tumor invasion and metastasis is previously unknown. Here, we report that FBXW2 is an E3 ligase for β-catenin. FBXW2 binds to β-catenin upon EGF-AKT1-mediated phosphorylation on Ser⁵⁵², and promotes its ubiquitylation and degradation. FBXW2 overexpression reduces β-catenin levels and protein half-life, whereas FBXW2 knockdown increases β-catenin levels, protein half-life and transcriptional activity. Functionally, FBXW2 overexpression inhibits migration and invasion by blocking transactivation of MMPs driven by β-catenin, whereas FXBW2 knockdown promotes migration, invasion and metastasis both in vitro and in vivo lung cancer models. In human lung cancer specimens, while FBXW2 levels are inversely correlated with β-catenin levels and lymph-node metastasis, lower FBXW2 coupled with higher β-catenin, predict a worse patient survival. Collectively, our study demonstrates that FBXW2 inhibits tumor migration, invasion and metastasis in lung cancer cells by targeting β-catenin for degradation.

FBXW2 is an F-box protein that target substrates for degradation through SCF E3 ligase. Here, the authors show that FBXW2 suppresses lung cancer migration and invasion by promoting degradation of β-catenin and this is dependent on EGF-AKT1.

SAG/RBX2 E3 Ubiquitin Ligase Differentially Regulates Inflammatory Responses of Myeloid Cell Subsets

Macrophages form an important component of the innate immune system and serve as first responders against invading pathogens. While pathways critical for initiation of inflammatory responses between macrophages and other LysM⁺ myeloid cells are largely similar, it remains unknown whether a specific pathway has differential effects on inflammatory responses mediated between these cells. Recent studies demonstrated that depletion of SAG (Sensitive to Apoptosis Gene), an E3 ubiquitin ligase, blocked inflammatory responses generated by macrophages and dendritic cells in response to LPS in cell culture settings. However, the in vivo role of Sag on modulation of macrophages and neutrophil is not known. Here we generated LysM-Cre/Sag ^fl/fl mice with selective Sag deletion in myeloid lineage, and found that in contrast to in vitro observations, LysM-Cre/Sag ^fl/fl mice showed increased serum levels of proinflammatory cytokines and enhanced mortality in response to LPS. Interestingly, while Sag ^-/- macrophages released less proinflammatory cytokines, Sag ^-/- neutrophils released more. Mechanistically, expression of a list of genes response to LPS was significantly altered in bone marrow cells from LysM-Cre ⁺/Sag ^fl/fl mice after LPS challenge. Specifically, induction by LPS of myeloperoxidase (Mpo), a key neutrophil enzyme, and Elane, neutrophil expressed elastase, was significantly decreased upon Sag depletion. Collectively, our study revealed that Sag plays a differential role in the activation of macrophages and neutrophils.

SCFβ-TrCP ubiquitinates CHK1 in an AMPK-dependent manner in response to glucose deprivation

The ATR/CHK1 pathway is a key effector of cellular response to DNA damage and therefore is a critical regulator of genomic stability. While the ATR/CHK1 pathway is often inactivated by mutations, CHK1 itself is rarely mutated in human cancers. Thus, cellular levels of CHK1 likely play a key role in the maintenance of genomic stability and preventing tumorigenesis. Glucose deprivation is observed in many solid tumors due to high glycolytic rates of cancer cells and insufficient vascularization, yet cancer cells have devised mechanisms to survive in conditions of low glucose. Although CHK1 degradation through the ubiquitin-proteasome pathway following glucose deprivation has been previously reported, the detailed molecular mechanisms remain elusive. Here, we show that CHK1 is ubiquitinated and degraded upon glucose deprivation by the Skp1-Cullin-F-box (β-TrCP) E3 ubiquitin ligase. Specifically, CHK1 contains a β-TrCP recognizable degron domain, which is phosphorylated by AMPK in response to glucose deprivation, allowing for β-TrCP to recognize CHK1 for subsequent ubiquitination and degradation. Our results provide a novel mechanism by which glucose metabolism regulates a DNA damage effector, and imply that glucose deprivation, which is often found in solid tumor microenvironments, may enhance mutagenesis, clonal expansion, and tumor progression by triggering CHK1 degradation.

Forensic Pathology Analysis of 363 Sudden Death Cases in Yunnan Province

OBJECTIVES

To study the epidemiological and pathological features of sudden death （SD） in Yunnan Province and to provide scientific evidence for prevention and forensic identification of sudden death.

METHODS

Totally 363 SD cases were collected from the autopsies between 2009 and 2017 in the Forensic Centre of Kunming Medical University. The related factors such as etiology, age, inducing factor, time interval between the onset of disease and death, morbidity season and pathological change were retrospectively analysed.

RESULTS

The incidence of SD in males was significantly higher than that of females. The peak age was ≥35-55 years. The mortality rate was relatively high within 6 h after the onset of disease. The season order with descending number of deaths was spring, summer, winter and autumn. The top ten causes of SD were coronary heart disease, sudden unexplained death （SUD）, cerebral hemorrhage, acute hemorrhagic necrotic pancreatitis, aortic dissection rupture, cardiomyopathy, pneumonia, pulmonary thromboembolism, amniotic fluid embolism and allergy. Exercise, infusion, surgery, medication and minor injury were the most common predisposing factors of sudden coronary death. Consciousness disorder or coma, chest pain or chest tightness, and abdominal pain were the most common premortem symptoms of sudden coronary death.

CONCLUSIONS

The SD is more common in middle-aged males, which is the key population for the prevention of SD. For the forensic identification and prevention of SD, the attention on SUD should be paid.

AKT inhibitor MK-2206 sensitizes breast cancer cells to MLN4924, a first-in-class NEDD8-activating enzyme (NAE) inhibitor

Breast cancer is a common type of cancer among female cancer patients and the main cause of cancer-related deaths. During the last decades, targeted therapies for breast cancer have been rapidly developing. Among them, MLN4924, a first-in-class NEDD8-activating enzyme (NAE) inhibitor, has performed antitumor activity by inactivating the cullin-RING ligases and causing the accumulation of their substrates to induce apoptosis in a number of studies. In this study, we found that MLN4924 activates the AKT pathway in both HER2-positive and triple-negative breast cancer (TNBC) cell lines. Given that AKT signaling is responsible for tumor progression and drug resistance in some types of cancers, we hypothesized that the AKT inhibitor may synergistically enhance the tumor suppression capability in breast cancer by MLN4924. To demonstrate the sensitizing effect, MK-2206 was chosen as the adjuvant treatment, and cell growth, migration and apoptosis were detected. The results showed that MLN4924 treatment inhibited cell growth and migration and induced apoptosis in both SK-BR3 and MDA-MB231 breast cancer cell lines. More importantly, the combined treatment of MLN4924 and MK-2206 indeed caused stronger cytotoxicity and inhibition of migration and a much higher induction of apoptosis compared with MLN4924 treatment alone. Our study provides the proof-of-concept evidence for strategic drug combination of MLN4924 with an AKT inhibitor for maximal killing of breast cancer cells via the enhancement of apoptosis.