The interaction between m⁶A-methylated RNA and chromatin modification remains largely unknown. We found that targeted inhibition of bromodomain-containing protein 4 (BRD4) by siRNA or its inhibitor (JQ1) significantly decreases mRNA m⁶A levels and suppresses the malignancy of breast cancer (BC) cells via increased expression of demethylase AlkB homolog 5 (ALKBH5). Mechanistically, inhibition of BRD4 increases the mRNA stability of ALKBH5 via enhanced binding between its 3' untranslated regions (3'UTRs) with RNA-binding protein RALY. Further, BRD4 serves as a scaffold for ubiquitin enzymes tripartite motif containing-21 (TRIM21) and ALKBH5, resulting in the ubiquitination and degradation of ALKBH5 protein. JQ1-increased ALKBH5 then demethylates mRNA of extra spindle pole bodies like 1 (ESPL1) and reduces binding between ESPL1 mRNA and m⁶A reader insulin like growth factor 2 mRNA binding protein 3 (IGF2BP3), leading to decay of ESPL1 mRNA. Animal and clinical studies confirm a critical role of BRD4/ALKBH5/ESPL1 pathway in BC progression. Further, our study sheds light on the crosstalks between histone modification and RNA methylation.

ABSTRCT AIM:To verify the effect of polygona-tum polysaccharide(PSP)combined with TGF-β3 in inducing the differentiation of rat tendon-derived stem cells(TDSCs)into chondrocytes by activating the TGF-β3/Smad2 pathway.METHODS:TDSCs were extracted from rat tail tendons using enzyme digestion,purified,passaged,and identified via flow cytometry.TDSCs were treated with different concentrations of PSP,and the optimal growth con-centration was determined using the CCK-8 assay.TDSCs were divided into four groups:PSP,TGF-β3,PSP+TGF-β3,and Control for differentiation induc-tion.Chondrogenic differentiation was evaluated using morphological observations,toluidine blue staining,immunofluorescence staining,and West-ern blot analysis to detect COLⅡ,SOX9,and AGG.Western blot was also used to measure the expres-sion levels of Smad2 and p-Smad2 to evaluate the activation of the TGF-β3/Smad2 pathway after chondrogenic induction.RESULTS:Flow cytometry analysis showed that TDSCs highly expressed CD90 and CD29,while CD11b and CD45 expression was low.The CCK-8 assay indicated that 5 μmol/L PSP was the optimal intervention dose.Toluidine blue staining revealed that the blue staining area in the PSP,PSP+TGF-β3,and TGF-β3 groups was larger compared to the Control group.Immunofluores-cence analysis demonstrated that COLⅡ expression was significantly increased in the PSP,TGF-β3,and PSP+TGF-β3 groups,with the highest expression in the PSP+TGF-β3 group(P＜0.05).Western blot analy-sis showed that the levels of p-Smad2/Smad2,COLⅡ,SOX9,and AGG were elevated in the PSP,TGF-β3,and PSP+TGF-β3 groups,with the highest ex-pression in the PSP+TGF-β3 group(P＜0.05).Compared to the Control group,the TGF-β3 and PSP groups also showed significantly increased expression(P＜0.05).CONCLUSION:PSP promotes the proliferation and chondrogenic differentiation of TDSCs,possibly by activating the TGF-β3/Smad2 pathway.

ABSTRCT AIM:To verify the effect of polygona-tum polysaccharide(PSP)combined with TGF-β3 in inducing the differentiation of rat tendon-derived stem cells(TDSCs)into chondrocytes by activating the TGF-β3/Smad2 pathway.METHODS:TDSCs were extracted from rat tail tendons using enzyme digestion,purified,passaged,and identified via flow cytometry.TDSCs were treated with different concentrations of PSP,and the optimal growth con-centration was determined using the CCK-8 assay.TDSCs were divided into four groups:PSP,TGF-β3,PSP+TGF-β3,and Control for differentiation induc-tion.Chondrogenic differentiation was evaluated using morphological observations,toluidine blue staining,immunofluorescence staining,and West-ern blot analysis to detect COLⅡ,SOX9,and AGG.Western blot was also used to measure the expres-sion levels of Smad2 and p-Smad2 to evaluate the activation of the TGF-β3/Smad2 pathway after chondrogenic induction.RESULTS:Flow cytometry analysis showed that TDSCs highly expressed CD90 and CD29,while CD11b and CD45 expression was low.The CCK-8 assay indicated that 5 μmol/L PSP was the optimal intervention dose.Toluidine blue staining revealed that the blue staining area in the PSP,PSP+TGF-β3,and TGF-β3 groups was larger compared to the Control group.Immunofluores-cence analysis demonstrated that COLⅡ expression was significantly increased in the PSP,TGF-β3,and PSP+TGF-β3 groups,with the highest expression in the PSP+TGF-β3 group(P＜0.05).Western blot analy-sis showed that the levels of p-Smad2/Smad2,COLⅡ,SOX9,and AGG were elevated in the PSP,TGF-β3,and PSP+TGF-β3 groups,with the highest ex-pression in the PSP+TGF-β3 group(P＜0.05).Compared to the Control group,the TGF-β3 and PSP groups also showed significantly increased expression(P＜0.05).CONCLUSION:PSP promotes the proliferation and chondrogenic differentiation of TDSCs,possibly by activating the TGF-β3/Smad2 pathway.

Previous studies suggest that the reduction of SMAD3 (mothers against decapentaplegic homolog 3) has a great impact on tumor development, but its exact pathological function remains unclear. In this study, we found that the protein level of SMAD3 was greatly reduced in human-grade IV glioblastoma tissues, in which LAMP2A (lysosome-associated membrane protein type 2A) was significantly up-regulated. LAMP2A is a key rate-limiting protein of chaperone-mediated autophagy (CMA), a lysosome pathway of protein degradation that is activated in glioma. We carefully analyzed the amino-acid sequence of SMAD3 and found that it contained a pentapeptide motif biochemically related to KFERQ, which has been proposed to be a targeting sequence for CMA. In vitro, we confirmed that SMAD3 was degraded in either serum-free or KFERQ motif deleted condition, which was regulated by LAMP2A and interacted with HSC70 (heat shock cognate 71 kDa protein). Using isolated lysosomes, amino-acid residues 75 and 128 of SMAD3 were found to be of importance for this process, which affected the CMA pathway in which SMAD3 was involved. Similarly, down-regulating SMAD3 or up-regulating LAMP2A in cultured glioma cells enhanced their proliferation and invasion. Taken together, these results suggest that excessive activation of CMA regulates glioma cell growth by promoting the degradation of SMAD3. Therefore, targeting the SMAD3-LAMP2A-mediated CMA-lysosome pathway may be a promising approach in anti-cancer therapy.

N ⁶-methyladenosine (m⁶A) modification is critical for mRNA splicing, nuclear export, stability and translation. Fat mass and obesity-associated protein (FTO), the first identified m⁶A demethylase, is critical for cancer progression. Herein, we developed small-molecule inhibitors of FTO by virtual screening, structural optimization, and bioassay. As a result, two FTO inhibitors namely 18077 and 18097 were identified, which can selectively inhibit demethylase activity of FTO. Specifically, 18097 bound to the active site of FTO and then inhibited cell cycle process and migration of cancer cells. In addition, 18097 reprogrammed the epi-transcriptome of breast cancer cells, particularly for genes related to P53 pathway. 18097 increased the abundance of m⁶A modification of suppressor of cytokine signaling 1 (SOCS1) mRNA, which recruited IGF2BP1 to increase mRNA stability of SOCS1 and subsequently activated the P53 signaling pathway. Further, 18097 suppressed cellular lipogenesis via downregulation of peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein alpha (C/EBPα), and C/EBPβ. Animal studies confirmed that 18097 can significantly suppress in vivo growth and lung colonization of breast cancer cells. Collectively, we identified that FTO can work as a potential drug target and the small-molecule inhibitor 18097 can serve as a potential agent against breast cancer.

Objective:To investigate the characteristics of senile neurodegenerative diseases (NDDs) inpatients in south China, especially in Guangdong province, and explore the influencing factors for their medical expenses.Methods:The medical records of 7231 patients with NDDs≥65 years were collected in the electronic health database of our hospital from January 2010 to December 2019, including gender, age, admission ways, chief complaints, length of hospital stays and medical expenses. On the basis of median of the medical expenses (21 345 yuan) of these patients, they were divided into low cost (<21 345 yuan) group and high cost (≥21 345 yuan) group. Univariate Logistic analysis and multivariate Logistic regression analysis were conducted to screen the influencing factors for medical expenses and the independent influencing factors.Results:(1) The main age group of geriatric inpatients with NDDs were 70-79 years (40.96%); the admission source was mainly outpatient (56.70%), and length of hospital stays of a large percent of patients (44.50%) were 8-14 d. (2) From 2010 to 2019, the number of hospitalized geriatric patients with NDDs showed an increasing trend year by year, the overall trend of length of hospital stays was shortened, and the medical expenses showed gradual increase; the causes of hospitalization, percentages of patients caused by infection, abnormal blood pressure and water-electrolyte metabolism disturbances showed decreased trend, percentages of patients caused by heart diseases, cerebrovascular accidents and mental-psychological diseases showed increased trend, and the proportions of patients caused by fracture/trauma/wound injuries were generally stable. The proportion of patients returning home and mortality rate after hospital discharge were declined, and the proportion of patients returning to other medical or community institutions was increased. (3) Living in ICU, length of hospital stays, diabetes, nosocomial infection, chronic kidney disease, urinary tract infection, tumble, body mass index, and anticholinergic drugs were independent risk factors influencing the medical expenses ( P<0.05). Conclusions:An aging trend is noted in patients with NDDs; the number of hospitalized patients and medical expenses increase year by year, and the length of hospital stays gradually decreases. In view of the many factors that influence the medical expenses of this disease, it is suggested to develop the corresponding standardized treatment plan for the main influencing factors in clinical practice.