[Application of omics in the diagnosis of metabolic dysfunction-associated fatty liver disease]

Metabolic dysfunction-associated fatty liver disease (MAFLD) is the most common chronic liver disease worldwide, and the risk of all-cause and liver-related mortality significantly increases with the degree of fibrosis. Early diagnosis of MAFLD and its degree of liver fibrosis are of great significance, so it is particularly important to find an accurate and simple, non-invasive diagnostic method. In recent years, high-throughput omics technology has developed rapidly and played an important role in the non-invasive diagnosis and prediction of fibrosis degree in MAFLD. This article summarizes the application progress of genomics, epigenomics, transcriptomics, proteomics, metabolomics, microbiomics, radiomics, and the combination of multi-omics for the diagnosis of MAFLD disease.

Nuclear Tubulin Enhances CXCR4 Transcription and Promotes Chemotaxis Through TCF12 Transcription Factor in human Hematopoietic Stem Cells

Tubulins are cytoskeleton components in all eukaryotic cells and play crucial roles in various cellular activities by polymerizing into dynamic microtubules. A subpopulation of tubulin has been shown to localize in the nucleus, however, the function of nuclear tubulin remains largely unexplored. Here we report that microtubule depolymerization specifically upregulates surface CXCR4 expression in human hematopoietic stem cells (HSCs). Mechanistically, microtubule depolymerization results in accumulation of tubulin subunits in the nucleus, leading to elevated CXCR4 transcription and increased chemotaxis of human HSCs. Treatment with microtubule stabilizer Epothilone B strongly suppresses the phenotypes induced by microtubule depolymerizing agents in human HSCs. Furthermore, chromatin immunoprecipitation assay reveals an increased binding of nuclear tubulin and TCF12 transcription factor at the CXCR4 promoter region. Depletion of TCF12 significantly suppresses microtubule depolymerization mediated upregulation of CXCR4 surface expression. These results demonstrate a previously unknown function of nuclear tubulin in regulating gene transcription through TCF12. New strategy targeting nuclear tubulin-TCF12-CXCR4 axis may be applicable to enhance HSC transplantation.

[Application of different prognostic scores in liver transplantation decision-making for acute-on-chronic liver failure]

Objective: To compare the impact of different prognostic scores in patients with acute-on-chronic liver failure (ACLF) in order to provide treatment guidance for liver transplantation. Methods: The information on inpatients with ACLF admitted at Beijing You'an Hospital Affiliated to Capital Medical University and the First Affiliated Hospital of Zhejiang University School of Medicine from January 2015 to October 2022 was collected retrospectively. ACLF patients were divided into liver transplantation and non-liver transplantation groups, and the two groups prognostic conditions were followed-up. Propensity score matching was carried out between the two groups on the basis of liver disease (non-cirrhosis, compensated cirrhosis, and decompensated cirrhosis), the model for end-stage liver disease incorporating serum sodium (MELD-Na), and ACLF classification as matching factors. The prognostic condition of the two groups after matching was compared. The difference in 1-year survival rate between the two groups was analyzed under different ACLF grades and MELD-Na scores. The independent sample t-test or rank sum test was used for inter-group comparison, and the χ (2) test was used for the comparison of count data between groups. Results: In total, 865 ACLF inpatients were collected over the study period. Of these, 291 had liver transplantation and 574 did not. The overall survival rates at 28, 90, and 360 days were 78%, 66%, and 62%, respectively. There were 270 cases of matched ACLF post-liver transplantation and 270 cases without ACLF, in accordance with a ratio of 1:1. At 28, 90, and 360 days, patients with non-liver transplantation had significantly lower survival rates (68%, 53%, and 49%) than patients with liver transplantation (87%, 87%, and 78%, respectively; P < 0.001). Patients were classified into four groups according to the ACLF classification criteria. Kaplan-Meier survival analysis showed that the survival rates of liver transplantation and non-liver transplantation patients in ACLF grade 0 were 77.2% and 69.4%, respectively, with no statistically significant difference (P = 0.168). The survival rate with an ACLF 1-3 grade was significantly higher in liver transplantation patients than that of non-liver transplantation patients (P < 0.05). Patients with ACLF grades 1, 2, and 3 had higher 1-year survival rates compared to non-liver transplant patients by 50.6%, 43.6%, and 61.7%, respectively. Patients were divided into four groups according to the MELD-Na score. Among the patients with a MELD-Na score of < 25, the 1-year survival rates for liver transplantation and non-liver transplantation were 78.2% and 74.0%, respectively, and the difference was not statistically significant (P = 0.149). However, among patients with MELD-Na scores of 25-30, 30-35, and≥35, the survival rate was significantly higher in liver transplantation than that of non-liver transplantation, and the 1-year survival rate increased by 36.4%, 54.9%, and 62.5%, respectively (P < 0.001). Further analysis of the prognosis of patients with different ACLF grades and MELD-Na scores showed that ACLF grades 0 or 1 and MELD-Na score of < 30 had no statistically significant difference in the 1-year survival rate between liver transplantation and non-liver transplantation (P > 0.05), but in patients with MELD-Na score≥30, the 1-year survival rate of liver transplantation was higher than that of non-liver transplantation patients (P < 0.05). In the ACLF grade 0 and MELD-Na score of≥30 group, the 1-year survival rates of liver transplantation and non-liver transplantation patients were 77.8% and 25.0% respectively (P < 0.05); while in the ACLF grade 1 and MELD-Na score of≥30 group, the 1-year survival rates of liver transplantation and non-liver transplantation patients were 100% and 20.0%, respectively (P < 0.01). Among patients with ACLF grade 2, the 1-year survival rate with MELD-Na score of < 25 in patients with liver transplantation was 73.9% and 61.6%, respectively, and the difference was not statistically significant (P > 0.05); while in the liver transplantation patients group with MELD-Na score of ≥25, the 1-year survival rate was 79.5%, 80.8%, and 75%, respectively, which was significantly higher than that of non-liver transplantation patients (36.6%, 27.6%, 15.0%) (P < 0.001). Among patients with ACLF grade 3, regardless of the MELD-Na score, the 1-year survival rate was significantly higher in liver transplantation patients than that of non-liver transplantation patients (P < 0.01). Additionally, among patients with non-liver transplantation with an ACLF grade 0~1 and a MELD-Na score of < 30 at admission, 99.4% survived 1 year and still had an ACLF grade 0-1 at discharge, while 70% of deaths progressed to ACLF grade 2-3. Conclusion: Both the MELD-Na score and the EASL-CLIF C ACLF classification are capable of guiding liver transplantation; however, no single model possesses a consistent and precise prediction ability. Therefore, the combined application of the two models is necessary for comprehensive and dynamic evaluation, but the clinical application is relatively complex. A simplified prognostic model and a risk assessment model will be required in the future to improve patient prognosis as well as the effectiveness and efficiency of liver transplantation.

AB0053 LncRNA NUTM2A-AS1 ALLEVIATED OSTEOARTHRITIS BY REGULATING miR-183-5p/TGFA PATHWAY

Background

Osteoarthritis(OA) is a common comorbidity in the elderly, characterized by articular cartilage degeneration, hyperosteogeny and synovitis. Long non-coding RNAs (LncRNAs) have been shown to be involved in several human diseases, including OA. However, the effect of NUTM2A-AS1 on chondrocytes remains unknown.

Objectives

The purpose of this study was to evaluate the role of LncRNA NUTM2A-AS1 in OA pathological changes in vitro.

Methods

Chondrocyte cells were treated for 24 hours to mimic OA pathological conditions. The experimental center used chondrocytes with interleukin-1 beta (IL-1β) Intervention to simulate the pathological state of OA.The expression levels of LncRNA NUTM2A-AS1, miR-183-5p and TGFA mRNA were detected by quantitative real-time PCR (qRT-PCR), along with CCK-8 to determine cell viability. Inflammatory response was assessed by determining the release of pro-inflammatory factors such as TNF-α and IL-6 using ELISA kits. Cell apoptosis was examined by flow cytometry assay. The binding relationship between miR-183-5p and LncRNA NUTM2A-AS1 or TGFA was confirmed by dual-luciferase reporter assay.

Results

IL-1β induced chondrocytes to express LncRNA NUTM2A-AS1 and TGFA, and the miR-183-5p expression was decreased in IL-1β-treated cells. Low expression of LncRNA NUTM2A-AS1 or TGFA mitigated IL-1β-caused chondrocyte viability reduction and apoptosis promotion. miR-183-5p overexpression alleviated IL-1β-mediated chondrocyte apoptosis and inflammatory injury via decreasing TGFA expression. In addition, our work revealed that miR-183-5p is a target of LncRNA NUTM2A-AS1. Rescue experiments showed that TGFA overexpression could reverse the effects of low expression of LncRNA NUTM2A-AS1 on the pathological changes in IL-1β-induced chondrocytes.

Conclusion

Low expression of LncRNA NUTM2A-AS1 significantly mitigated the chondrocytes damage induced by IL-1β through regulating miR-183-5p/TGFA axis, which might be an important target to regulate the promotion of OA.

References

[1]Kong H, Sun ML, Zhang XA, Wang XQ. Crosstalk Among circRNA/lncRNA, miRNA, and mRNA in Osteoarthritis[J]. Front Cell Dev Biol, 2021, 9:77437

Disclosure of Interests

None declared

PAK5 promotes RNA helicase DDX5 sumoylation and miRNA-10b processing in a kinase-dependent manner in breast cancer

P21-activated kinase 5 (PAK5) plays an important role in tumors. However, the functional role of PAK5 in mammary tumorigenesis in vivo remains unclear. Here, we show that PAK5 deficiency represses MMTV-PyVT-driven breast tumorigenesis. DEAD-box RNA helicase 5 (DDX5) is a substrate of PAK5, which is phosphorylated on threonine 69. PAK5-mediated DDX5 phosphorylation promotes breast cancer cell proliferation and metastasis. The increased expression levels of PAK5 and phospho-DDX5 threonine 69 are associated with metastasis and poor clinical outcomes of patients. PAK5 facilitates the phosphorylation-dependent sumoylation of DDX5 to stabilize DDX5. Both the phosphorylation and sumoylation of DDX5 enhance the formation of a DDX5/Drosha/DGCR8 complex, thus promoting microRNA-10b processing. Finally, we verify decreased expression of DDX5 phosphorylation and sumoylation and mature miR-10b in PAK5^-/-/MMTV-PyVT transgenic mice. Our findings provide insights into the function of PAK5 in microRNA (miRNA) biogenesis, which might be a potential therapeutic target for breast cancer.

[Aldo-keto reductase family 1 B10 participates in the regulation of hepatoma cell cycle through p27/p-Rb signaling pathway]

Objective: Aldo-keto reductase family 1 member B10 (AKR1B10) pathogenesis, early diagnosis and prognosis are closely related with hepatoma. Therefore, this study explores the effect and mechanism of AKR1B10 on cell cycle in hepatoma cells. Methods: HepG2 cells were infected with lentivirus LV-AKR1B10-shRNA or treated with epalrestat, an AKR1B10 inhibitor. The expression level of AKR1B10 was detected by Western blot assay and real-time fluorescence quantitative PCR (RT-qPCR). Decreased AKR1B10 activity was detected by reduced coenzyme II (NADPH) absorbance at 340 nm. The low expression of AKR1B10 and the effect of different concentrations of epalrestat on cell proliferation and cell cycle were detected by CCK-8 method and flow cytometry. The protein expression levels of p-rb, cyclin D1, E1, p27 in HepG2 cells were detected by Western blot. The mean of the two samples was tested using independent sample t-test. Results: AKR1B10 expression level in hepatoma cells was significantly increased compared to normal liver cells, and the relative expression level of AKR1B10 protein in HepG2 cells was 6.71 ± 1.11 (P = 0.012). Epalrestat was significantly inhibited with the enzymatic activity of AKR1B10 in a dose-dependent manner. AKR1B10 gene in HepG2 cells was effectively silenced. HepG2 cells treated with different concentrations of epalrestat (AKR1B10 inhibitor) for 24, 48 and 72 h had inhibited cell proliferation, promoted G0/G1 cell cycle arrest, reduced the expression of p-Rb, cyclin D1, and cyclin E1 and increased the expression of cyclin dependent kinase inhibitor p27 expression. Conclusion: AKR1B10 inhibitory expression and activity can promote G0/G1 cell cycle arrest in HepG2 cells through the p27 / p-Rb pathway.

Knockdown of ferroportin accelerates erastin-induced ferroptosis in neuroblastoma cells

OBJECTIVE

Ferroptosis is a new-found iron-dependent form of non-apoptotic regulated cell death (RCD), which is activated on therapy with several antitumor agents, but the potential mechanism remains unclear. Erastin, exhibiting selectivity for RAS-mutated cancer cells, induces ferroptosis by increasing iron and lipid reactive oxygen species (ROS) levels in cell. Ferroportin (Fpn), the sole iron export protein, participates in the regulation of intracellular iron concentration. In this study, we investigated the role of Fpn on ferroptosis induced by erastin in SH-SY5Y cells.

MATERIALS AND METHODS

The cell viability was determined by CellTiter 96® AQueous Non-Radioactive Cell Proliferation Assay kit. The activity of caspase-3 was measured by ELISA kit. qRT-PCR was performed to examine the mRNA expression of Fpn. Western blot assay was conducted to examine the expression level of marker proteins. Specific commercial kits were used to examine the levels of MDA, ROS and iron in cells, respectively.

RESULTS

Ferroptosis was evaluated by intracellular lipid ROS level and iron concentration. Hepcidin could prevent erastin-induced ferroptosis by degrading Fpn. Erastin (5 μg/mL) was observed to induce ferroptosis in neuroblastoma cells at 6 hours, which was promoted by knockdown of Fpn. The expression of Fpn gene and protein was decreased in SH-SY5Y cells treated with erastin. After treatment with erastin, Fpn siRNA transfection in SH-SY5Y cells was able to accelerate ferroptosis-associated phenotypic changes. Fpn acted as a negative regulator of ferroptosis by reducing intracellular iron concentration. Knockdown of Fpn enhanced anticancer activity of erastin.

CONCLUSIONS

These results suggested that knockdown of Fpn accelerated erastin-induced ferroptosis by increasing iron-dependent lipid ROS accumulation, highlighting Fpn as a potential therapeutic target site for neuroblastoma. Thus, Fpn inhibitors may provide new access for chemosensitization of neuroblastoma.

Aspartyl Aminopeptidase Suppresses Proliferation, Invasion, and Stemness of Breast Cancer Cells via Targeting CD44

Although involved in diverse cancer processes, the function of aspartyl aminopeptidase (DNPEP) in breast cancer remains elusive. Here, we reported that DNPEP is significantly downregulated in breast cancer tissues. Overexpression of DNPEP resulted in decreased breast cancer cells proliferation, migration, and invasion, while DNPEP knockdown had the opposite effect. Interestingly, we showed that the reduced DNPEP levels were correlated with the elevated cluster of differentiation 44 (CD44) levels in breast cancer. DNPEP promoted CD44 ubiquitin-proteasome-independent degradation, which is dependent on the hydrolase activity of DNPEP. Ectopic DNPEP expression significantly suppressed the stemness properties of breast cancer cells. These results shed light on the prospect of DNPEP in manipulating breast cancer progression. Anat Rec, 302:2178-2185, 2019. © 2019 American Association for Anatomy.

A PAK5-DNPEP-USP4 axis dictates breast cancer growth and metastasis

Although clinically associated with the progression of multiple cancers, the biological function of p21-activated kinase 5 (PAK5) in breast cancer remains largely unknown. Here, we reveal that the PAK5-aspartyl aminopeptidase (DNPEP)-ubiquitin-specific protease 4 (USP4) axis is involved in breast cancer progression. We show that PAK5 interacts with and phosphorylates DNPEP at serine 119. Functionally, we demonstrate that DNPEP overexpression suppresses breast cancer cell proliferation and invasion and restricts breast cancer growth and metastasis in mice. Furthermore, we identify USP4 as a downstream target of the PAK5-DNPEP pathway; DNPEP mediates USP4 downregulation. Importantly, we verify that DNPEP expression is frequently downregulated in breast cancer tissues and is negatively correlated with PAK5 and USP4 expression. PAK5 decreases DNPEP abundance via the ubiquitin-proteasome pathway. Consistently, analyses of clinical breast cancer specimens revealed significantly increased PAK5 and USP4 levels and an association between higher PAK5 and USP4 expression and worse breast cancer patient survival. These findings suggest a pivotal role for PAK5-elicited signaling in breast cancer progression.

SIRT1 modulates cell cycle progression by regulating CHK2 acetylation-phosphorylation

Both the stress-response protein, SIRT1, and the cell cycle checkpoint kinase, CHK2, play critical roles in aging and cancer via the modulation of cellular homeostasis and the maintenance of genomic integrity. However, the underlying mechanism linking the two pathways remains elusive. Here, we show that SIRT1 functions as a modifier of CHK2 in cell cycle control. Specifically, SIRT1 interacts with CHK2 and deacetylates it at lysine 520 residue, which suppresses CHK2 phosphorylation, dimerization, and thus activation. SIRT1 depletion induces CHK2 hyperactivation-mediated cell cycle arrest and subsequent cell death. In vivo, genetic deletion of Chk2 rescues the neonatal lethality of Sirt1^−/− mice, consistent with the role of SIRT1 in preventing CHK2 hyperactivation. Together, these results suggest that CHK2 mediates the function of SIRT1 in cell cycle progression, and may provide new insights into modulating cellular homeostasis and maintaining genomic integrity in the prevention of aging and cancer.

[AKR1B10 inhibitor enhances the inhibitory effect of sorafenib on liver cancer xenograft]

Objective: To investigate the inhibitory effect of AKR1B10 inhibitor combined with sorafenib on hepatocellular carcinoma (HCC) xenograft growth. Methods: HepG2 xenograft model was established in nude mice. The mice were then randomly divided into four groups: control group, epalrestat monotherapy group, sorafenib monotherapy group and combination treatment group. Tumor volume, tumor weight, T/C ratio and the change in body weight of nude mice in each group were compared to evaluate the curative effect. Immunohistochemistry staining was used to detect the expression of Ki-67 in tumor tissues to evaluate the proliferation status of tumor cells. One-way analysis of variance was used to compare the differences between the groups. Student's t-test was used to test means of two groups and chi-square test was used for multiple samples. Results: The differences of the grafted tumor volume before and after treatment between the control group, epalrestat group, sorafenib group and combined therapy group was 238.940 ± 39.813, 124.991 ± 84.670, -26.111 ± 11.518, and -54.072 ± 17.673(mm(3)), respectively, (F = 37.048, P < 0.001). The tumor mass were 0.273 ± 0.140, 0.158 ± 0.078, 0.079 ± 0.054, 0.045 ± 0.024 (g), (F = 16.594, P < 0.001); T/C ratio were 100%, 57.9%, 28.9%, 16.5%, and Ki-67 positive rate were 23.295 ± 6.218, 13.503 ± 3.392, 7.325 ± 2.257, 4.664 ± 1.189 (%), (χ(2) = 822.203, P < 0.001) . The tumor volume (t = -3.579, P = 0.002) and Ki-67 positive rate (t = -10.003, P < 0.001) in epalrestat monotherapy group were significantly lower than control group. The tumor volume (t = 2.056, P = 0.025), tumor mass (t = 2.101, P = 0.043), and Ki-67 positive rate (t = -2.850, P = 0.005) in combination treatment group were significantly lower than sorafenib monotherapy group. Compared with the control group, the body weight of nude mice in the treatment group decreased to a certain extent, but there was no statistically significant difference between epalrestat monotherapy group and control group (t = -1.599, P = 0.262), and combined therapy and sorafenib monotherapy group (t = -0.051, P = 0.96). Conclusion: AKR1B10 inhibitor enhanced the inhibitory effect of sorafenib on hepatocellular carcinoma xenograft.

[Low-levels of HBsAg quantification at 48-week in HBeAg-negative chronic hepatitis B patients are the advantageous population for HBsAg clearance]

Objective: To analyze the therapeutic effect on HBeAg-negative chronic hepatitis B patients treated with Peg-IFNα-2a combined with NAs to obtain the influencing factors for predicting HBsAg clearance. Methods: A retrospective study was conducted to investigate the effect of pegylated interferon alpha-2a combined with nucleoside analogues (lamivudine/adefovir dipivoxil) on HBeAg-negative chronic hepatitis B. The treatment course was 96 weeks. Patients were followed up 120 weeks after the treatment. HBsAg clearance at 120 weeks was taken as the objective of the study. Logistic regression and receiver operating characteristic curve analysis screened the related factors affecting HBsAg clearance. χ (2) test was used to compare count data. Results: 111 patients were treated with pegylated interferon alpha-2a combined with nucleoside analogues, and 107 patients completed the scheduled course of treatment and follow-up. HBsAg clearance rate at120 week was 29.0% (31/107). The influencing factors for analysis were: (1) gender had no effect on HBsAg clearance rate; age and baseline levels of HBV DNA and alanine aminotransferase had no significant effect on HBsAg clearance; low baseline level of HBsAg (< 3.023 lgIU/ml) was beneficial to HBsAg clearance. The area under the working characteristic curve of the subjects was 0.746, the positive predictive value was 44.4%, and the negative predictive value was 86.8%. (2) HBsAg quantification or decline in 24 weeks and 48 weeks of treatment had a good predictive effect on HBsAg clearance, and the 48 weeks predicted value was higher than 24 weeks. When the HBsAg quantification was≤2.070 lgIU/ml at 48 weeks, the area under the receiver operating characteristic curve was 0.931, the positive predictive value was 52.8%, and the negative predictive value was 94.4%. When HBsAg decreased from baseline to≥0.991 lgIU/ml, the area under the receiver operating characteristic curve was 0.888, the positive predictive value was 50.8%, and the negative predictive value was 97.9%. (3) The analysis of HBsAg subgroup levels at 48 weeks suggested that the "interval analysis" can forecast HBsAg clearance more exactly than "nodal analysis" .The final HBsAg clearance rate of 100 IU/ml < HBsAg≤1 000 IU/ml, 10 IU/ml < HBsAg≤100 IU/ml and HBsAg≤10 IU/ml groups reached 6.7%, 31.8% and 67.7%, respectively. (4) The ALT abnormal group in the course of treatment obtained a higher HBsAg clearance rate (48.0%, 12/25). Conclusion: 96-weeks long-term treatment with pegylated interferon-alpha -alpha-2a combined with nucleoside analogues for HBeAg-negative chronic hepatitis B has a good predictive value for HBsAg clearance at baseline and during treatment. The "interval level" of HBsAg at 48-weeks is more accurate in predicting HBsAg clearance, suggesting that HBeAg-negative chronic hepatitis B patients with low HBsAg levels at 48-weeks are the advantageous populations with HBsAg clearance. These patients are worthy of prolonged treatment to pursue "clinical cure".

A novel PAK4-CEBPB-CLDN4 axis involving in breast cancer cell migration and invasion

Claudin-4 (CLDN4), a crucial member of tight junction proteins, is aberrantly expressed in breast cancer cells and contributes to cell migration and invasion. However, the mechanisms controlling CLDN4 expression in breast cancer are poorly understood. Here, we reported that CLDN4 expression correlated positively with p21-activated kinase 4 (PAK4) expression in human breast cancer tissues. Knockdown of PAK4 in MDA-MB-231 and ZR-75-30 cells suppressed CLDN4 expression and significantly inhibited cell migration and invasion. Conversely, restoration of CLDN4 expression in PAK4-knockdown cells reversed the inhibition of migration and invasion. We identified CCAAT/enhancer-binding protein β (CEBPB) as a novel transcriptional regulator of CLDN4 and confirmed that CEBPB bound to the -1093 to -991 bp region of the CLDN4 promoter. Importantly, we found that PAK4 enhanced CEBPB phosphorylation on Thr-235. In summary, we showed that PAK4-mediated CEBPB activation upregulated CLDN4 expression to promote breast cancer cell migration and invasion. Our results might contribute to understanding the mechanisms of CLDN4 regulation and suggest PAK4-CEBPB-CLDN4 axis as a potential therapeutic target for breast cancer.

A mandatory role of nuclear PAK4-LIFR axis in breast-to-bone metastasis of ERα-positive breast cancer cells

The mechanism of estrogen receptor alpha (ERα)-positive breast cancer-associated bone metastasis is poorly understood. In this article, we report that nuclear p21-activated kinase 4 (nPAK4) is a novel repressor of ERα-mediated transactivation in a 17β-estradiol (E2)-dependent manner and promotes PAK4–ERα axis-mediated bone metastasis by targeting leukemia inhibitory factor receptor (LIFR) in ERα-positive breast cancer. An evaluation of clinical breast cancer samples revealed that nPAK4 is linked to ERα expression and appears to be associated with a poor prognosis in bone metastatic breast cancer. PAK4 bound and co-translocated with ERα from the cytoplasm to the nucleus upon stimulation with E2. nPAK4 enhanced the invasive potential of ERα-positive breast cancer cells in vitro and promoted breast cancer metastasis in vivo. Mechanistically, nPAK4 promoted the metastasis of ERα-positive breast cancer cells by targeting LIFR, a bone metastasis suppressor. Strikingly, the nuclear accumulation of PAK4 might promote aggressive phenotypes, highlighting nPAK4 as a novel predictive biomarker for ERα-positive breast cancer bone metastasis.

[Effect of chitooligosaccharide on hepatic triglyceride metabolism and related mechanisms]

OBJECTIVE

To investigate the effect of chitooligosaccharide (COS) on hepatic triglyceride (TG) metabolism and related mechanisms.

METHODS

The LO2 cells treated by 1 mmol/L fatty acid were used as model group, the cells treated by 1 mmol/L fatty acid and 0.5 mg/ml COS were used as COS group, and the untreated cells were used as control group. The TG content in cells was measured. RT-PCR and Western blot were used to measure the mRNA and protein expression of sterol regulatory element binding protein-1c (SREBP-1c), fatty acid synthase (FAS), and carnitine palmityl transferase 1A (CPT1A) in each group. Male C57BL/6J mice were randomized into control group, high-fat group, and COS group to receive different treatments. Sixteen weeks later, the liver was harvested for HE and oil red O staining to measure the content of TG in the liver. The t-test or one-way analysis of variance was used for comparison of data between groups, and the SNK method was used for comparison of data between any two groups.

RESULTS

The LO2 cells in the model group had an increased number of lipid droplets and an increased TG content, and after COS treatment, the TG content was low. The COS group had significantly lower relative mRNA expression of SREBP-1c and FAS compared with the model group (1.135 ± 0.177 vs 2.322 ± 0.198,F= 60.457,P< 0.01; 1.226 ± 0.150 vs 1.801 ± 0.159,F= 24.753,P< 0.01), while compared with the control group, the COS group had significantly higher mRNA expression of CPT1A (1.254 ± 0.156 vs 1.908 ± 0.087,F= 31.734,P< 0.01). The COS group had significantly lower protein expression of SREBP-1c and FAS than the model group (0.161 ± 0.081 vs 0.351±0.016,F= 188.920,P< 0.01; 0.332 ± 0.023 vs 1.238 ± 0.051,F= 624.069,P< 0.01), and significantly higher protein expression of CPT1A than the model group (1.014 ± 0.033 vs 0.561 ± 0.046,F= 193.793,P< 0.01). COS reduced the TG content in the liver in rats on high-fat diet.

CONCLUSION

COS can reduce the accumulation of TG in the hepatocyte model of nonalcoholic fatty liver disease and in the liver in rats on high-fat diet, and the possible mechanism may be related to inhibiting the expression of SREBP-1c and downstream FAS, reducing the synthesis of TG, increasing the expression of CPT1A, and accelerating the breakdown of TG.

GATA1 induces epithelial-mesenchymal transition in breast cancer cells through PAK5 oncogenic signaling

Epithelial-mesenchymal transition (EMT) is a key process in tumor metastatic cascade that is characterized by the loss of cell-cell junctions, resulting in the acquisition of migratory and invasive properties. E-cadherin is a major component of intercellular junctions and the reduction or loss of its expression is a hallmark of EMT. Transcription factor GATA1 has a critical anti-apoptotic role in breast cancer, but its function for metastasis has not been investigated. Here, we found that GATA1, as a novel E-cadherin repressor, promotes EMT in breast cancer cells. GATA1 binds to E-cadherin promoter, down-regulates E-cadherin expression, disrupts intercellular junction and promotes metastasis of breast cancer cell in vivo. Moreover, GATA1 is a new substrate of p21-activated kinase 5 (PAK5), which is phosphorylated on serine 161 and 187 (S161 and S187). GATA1 recruits HDAC3/4 to E-cadherin promoter, which is reduced by GATA1 S161A S187A mutant. These data indicate that phosphorylated GATA1 recruits more HDAC3/4 to promote transcriptional repression of E-cadherin, leading to the EMT of breast cancer cells. Our findings provide insights into the novel function of GATA1, contributing to a better understanding of the EMT, indicating that GATA1 and its phosphorylation may play an important role in the metastasis of breast cancer.

Renin-angiotensin system inhibitors for prevention of recurrent atrial fibrillation: a meta-analysis

INTRODUCTION

Conflicting results exist now on the clinical utility of renin-angiotensin system (RAS) inhibitors in patients with atrial fibrillation (AF). This study aimed to elaborate the efficacy and safety of RAS blockade on preventing the relapse of AF by a meta-analysis based on randomised controlled trials (RCTs).

METHODS

We searched Medline, ISI web of science and Cochrane databases through Jan 2012. We included RCTs comparing RAS inhibition treatment vs. placebo or alternative therapy after cardioversion of persistent AF or conventional medical therapy for paroxysmal AF and reporting outcome of recurrent AF. Odds ratios (OR) were calculated using a random effects model.

RESULTS

Fifteen trials involving 3972 AF patients were included in the analysis. The pooling analysis showed that RAS inhibitors significantly reduced the recurrence of AF compared with non-RAS inhibitors (OR=0.50, 95% CI: 0.37-0.69, p<0.01), and the beneficial effect was shown consistently both in patients with paroxysmal and in those with persistent AF after cardoversion. However, administration of RAS inhibitors did not provide a greater survival advantage and a lower incidence of adverse effects than the control (OR=1.17, 95% CI, 0.65-2.10, p=0.59; OR=0.94, 95% CI: 0.65-1.35, p=0.73 respectively). In addition, clinical factors potentially affecting AF relapsing had no pronounced impacts on the above clinical outcomes.

CONCLUSIONS

Based on the currently available data, inhibition of RAS is effective, safe and well tolerated for preventing the recurrence of AF.

Telomerase inhibition strategies by siRNAs against either hTR or hTERT in oral squamous cell carcinoma

Human telomerase RNA (hTR) and human telomerase reverse transcriptase (hTERT) are considered effective molecular targets for current anticancer therapy. In this study, we investigated the therapeutic effects of targeting hTR and hTERT individually or in combination by recombinant adenovirus-delivered small interfering RNA (siRNA) in oral squamous cell carcinoma (OSCC) Tca8113. Further, we screened the optimal strategy for RNA interference. Our results show that these different recombinant adenoviruses specifically reduced the levels of hTR mRNA, hTERT mRNA, hTERT protein and telomerase activity in Tca8113 cells. Moreover, they successfully inhibited xenograft tumor growth in nude mice. The potency of their antitumor activities was ranked as follows: anti-hTR >anti-hTR+anti-hTERT >anti-hTERT. Therefore, we demonstrated that the siRNA-expressing recombinant adenoviruses were an effective anticancer tool for treatment of OSCC. Furthermore, the anticancer effect of solely targeting hTR was more direct and efficient, compared with the effect of targeting hTR and hTERT in combination, or hTERT exclusively. The mechanism of this anticancer effect in OSCC was not only related to the inhibition of cell proliferation and the induction of cell apoptosis, but might also involve the inhibition of tumor angiogenesis.