Diphthamide deficiency promotes association of eEF2 with p53 to induce p21 expression and neural crest defects.

Diphthamide is a modified histidine residue unique for eukaryotic translation elongation factor 2 (eEF2), a key ribosomal protein. Loss of this evolutionarily conserved modification causes developmental defects through unknown mechanisms. In a patient with compound heterozygous mutations in Diphthamide Biosynthesis 1 (DPH1) and impaired eEF2 diphthamide modification, we observe multiple defects in neural crest (NC)-derived tissues. Knockin mice harboring the patient's mutations and Xenopus embryos with Dph1 depleted also display NC defects, which can be attributed to reduced proliferation in the neuroepithelium. DPH1 depletion facilitates dissociation of eEF2 from ribosomes and association with p53 to promote transcription of the cell cycle inhibitor p21, resulting in inhibited proliferation. Knockout of one p21 allele rescues the NC phenotypes in the knockin mice carrying the patient's mutations. These findings uncover an unexpected role for eEF2 as a transcriptional coactivator for p53 to induce p21 expression and NC defects, which is regulated by diphthamide modification.

Validated Tools for Screening Sarcopenia: A Scoping Review.

OBJECTIVE: Choosing the optimal sarcopenia screening tool for a specific clinical scenario is challenging. We aimed to summarize all validated sarcopenia screening tools with diagnostic accuracy tested in one or more study populations. DESIGN: Scoping review. SETTING AND PARTICIPANTS: Hospitals, nursing homes, communities, or health checkups. METHODS: We systematically searched 3 databases in April 2022: MEDLINE, EMBASE, and CENTRAL. Two review authors independently performed the study selection and data extraction. The included tools' contents, characteristics, and number of citations were summarized and visualized. RESULTS: We summarized 102 diagnostic accuracy studies involving 53 screening tools, classified into 7 groups: questionnaires (n = 13); serum biomarkers (n = 10); formulas, algorithms, and models (n = 9); physical ability tests (n = 9); integration tools (n = 7); anthropometric indices (n = 3); and ultrasound or bioimpedance analysis (n = 2). The most commonly used questionnaire was SARC-F (770 citations), followed by SARC-CalF (254 citations) and MSRA-7 (61 citations). Handgrip strength and Ishii score were the most widely used physical performance tests (331 citations) and formulas (294 citations), respectively. Sarcopenia index (based on serum cystatin C and creatinine) and calf circumference were the most commonly used serum biomarkers (123 citations) and anthropometric indexes (127 citations), respectively. Ultrasound was the most commonly used imaging tool for screening sarcopenia (57 citations). The included tools varied significantly in content. Various tools assessed some or all components of sarcopenia with different methods, and others assessed different domains, such as age, body mass index, falls, diet, and even mental health. We also summarized the screening tools that were validated in different clinical settings (hospitals, communities, nursing homes, and health checkups). CONCLUSIONS AND IMPLICATIONS: More than 50 validated tools are currently available for screening sarcopenia in different clinical settings. The results of this review may help clinicians and researchers in selecting optimal tools for sarcopenia in different clinical scenarios and in developing future tools.

Transcriptional activation of CSTB gene expression by transcription factor Sp3.

CSTB has been reported to be associated with the pathogenesis of many malignant tumors, especially hepatocellular carcinoma (HCC). However, how the expression of this gene is regulated is largely unknown. We initially cloned and analyzed the promoter region of the CSTB gene by luciferase assay and the Sp3 binding site (CCCCGCCCCGCG) was found in it. The results of electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) experiments verified that the transcription factor, Sp3 could bind to the " CCCCGCCCCGCG ″ site of the CSTB gene promoter. We showed that the overexpression of Sp3 significantly increased the endogenous mRNA and protein expression levels of CSTB, whereas knockdown of Sp3 decreased the mRNA and protein expression levels according to quantitative real-time PCR (qRT‒PCR) and western blotting. In conclusion, CSTB gene expression is closely regulated by transcription factor Sp3, which may be a potential mechanism for the dysregulation of CSTB expression in HCC.

Capecitabine induces hand-foot syndrome through elevated thymidine phosphorylase-mediated locoregional toxicity and GSDME-driven pyroptosis that can be relieved by tipiracil.

BACKGROUND: Hand-foot syndrome (HFS) is a serious dose-limiting cutaneous toxicity of capecitabine-containing chemotherapy, leading to a deteriorated quality of life and negative impacts on chemotherapy treatment. The symptoms of HFS have been widely reported, but the precise molecular and cellular mechanisms remain unknown. The metabolic enzyme of capecitabine, thymidine phosphorylase (TP) may be related to HFS. Here, we investigated whether TP contributes to the HFS and the molecular basis of cellular toxicity of capecitabine. METHODS: TP-/- mice were generated to assess the relevance of TP and HFS. Cellular toxicity and signalling mechanisms were assessed by in vitro and in vivo experiments. RESULTS: TP-/- significantly reduced capecitabine-induced HFS, indicating that the activity of TP plays a critical role in the development of HFS. Further investigations into the cellular mechanisms revealed that the cytotoxicity of the active metabolite of capecitabine, 5-DFUR, was attributed to the cleavage of GSDME-mediated pyroptosis. Finally, we demonstrated that capecitabine-induced HFS could be reversed by local application of the TP inhibitor tipiracil. CONCLUSION: Our findings reveal that the presence of elevated TP expression in the palm and sole aggravates local cell cytotoxicity, further explaining the molecular basis underlying 5-DFUR-induced cellular toxicity and providing a promising approach to the therapeutic management of HFS.

Sp4 Regulates PTTG1IP Gene Transcription and Expression.

Pituitary tumor-transforming gene 1 protein (PTTG)-interacting protein, also known as PTTG-binding factor (PBF), is encoded by a proto-oncogene PTTG1IP. PBF has been identified through its interaction with PTTG. Similar to PTTG, PBF has been implicated in the etiology of several tumors, including pituitary, thyroid, and breast cancer. PBF can induce the translocation of PTTG into the nucleus, and then lead to tumorigenesis. Studies have shown that PBF plays a vital and complex role in increasing tumor development. However, the transcriptional regulation of PTTG1IP gene remains undefined. In this study, we have cloned a 467-bp fragment of the 5' flanking region of the human PTTG1IP gene and identified the region (-212 to +7 bp) necessary for PTTG1IP gene promoter activity by luciferase assay. Electrophoretic mobility shift assay revealed PTTG1IP gene promoter containing Sp4 response elements. Overexpression of Sp4 increased PTTG1IP gene transcription and expression in HeLa cells. Our study demonstrates that Sp4 regulates PTTG1IP gene transcription and expression.

Higher uric acid serum levels are associated with sarcopenia in west China: a cross-sectional study.

BACKGROUND: Sarcopenia is the decline in muscle strength and mass attributed to aging. The pathogenesis of sarcopenia may be triggered by oxidative stress and uric acid (UA) has strong antioxidant properties. The aim of this study was to investigate the relationship between UA and sarcopenia in community-dwelling adults of West China using the baseline data of West China Health and Aging Trend (WCHAT) study. DESIGN: A cross-sectional study. METHODS: 4236 adults aged 50 years or older in communities of west China were enrolled in this study. We applied Asian Working Group for Sarcopenia (AWGS) 2019 criteria to define sarcopenia. Muscle mass was measured using skeletal muscle index (SMI) based on bioimpedance analysis (BIA). Handgrip strength (HGS) and gait speed (GS) were recorded, respectively. Different variables like anthropometry measures, life styles, chronic disease and blood test were collected. General linear model was done to investigate the relationship between UA and HGS/GS/SMI, adjusting age, ethnic groups, sleeping quality, education level, cognitive function, smoking history, drinking history, ADL score, and chronic disease. RESULTS: Participants were grouped according to UA quartiles by gender. After adjusting for potential confounders, a negative association between serum UA levels and sarcopenia was shown both in men and women. And a significant association between serum UA levels and HGS in women was shown as an inverted J shape. Besides, a positive association between the UA quartiles and SMI was observed, irrespective of gender. CONCLUSIONS: Our results showed that higher uric acid levels were significantly correlated with higher muscle mass and grip strength among Chinese adults aged over 50. Higher UA serum levels might slow down the progression of sarcopenia.

Synthesis and assessment of the antioxidant and antitumor properties of asymmetric curcumin analogues.

In this study, 12 asymmetric curcumin (CUR) analogues and 5 symmetric curcumin derivatives were synthesized, the antioxidant activity of these derivatives were evaluated by radicals 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay, 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) assay, ROO (TRAP) assay and O(2-) (NET) assay and anti-proliferative activities of these analogues were assessed against the human hepatoma cell line (SMMC-7721), the human breast cancer cell line (MCF-7) and the human prostate cancer cell lines (PC-3). Most of the asymmetric compounds showed stronger antioxidant activities than Vitamin C (Vc). Curcumin analogues reducing free radicals contain two reaction mechanisms: H-atom and electron transfer mechanisms. Compound 14 showed the most significant antioxidant activity compared with curcumin and other derivatives. Shorted the carbon chain of 14 can reduce the O-H bond dissociation enthalpy (BED) to improve the antioxidant activity. The antioxidant activity of 25 was similar to curcumin. All of the compounds performed better in an anti-proliferate assay than curcumin, especially compound 25, which exhibited the preferential cytotoxic activity against MCF-7 cells(25, IC50 = 9.11 µM, curcumin, IC50 = 70.2 µM). Considering these data, future studies should be performed to assess the therapeutic values of these asymmetric curcumin analogues.

Transport and killing mechanism of a novel camptothecin-deoxycholic acid derivate on hepatocellular carcinoma cells.

Abstract Camptothecin-20(s)-O-glycine ester-[N-(3'α, 12'α-dihydroxy-24'-carbonyl-5'ß-cholan)] (A2), 10-(3'α,12'α-dihydroxy-5'ß-cholan-24'-carboxyl)-(20 s)-camptothecin (C2), and 10-O-(3-O-(3'α, 12'α-dihydroxy-24'-carbonyl-5'ß-cholan)-propyl)-(20S)-camptothecin (D2) are novel camptothecin-deoxycholic acid analogues. MTT assays were performed to assess the anticancer activity of these compounds against hepatocellular carcinoma SMMC-7721, breast carcinoma MCF-7, and colorectal carcinoma HCT-116 cells. A2 had a high killing ability on SMMC-7721 cells selectively, but C2 and D2 did not exhibit selectivity with regard to SMMC-7721 killing. Uptake assays were performed in an effort to elucidate the transport mechanisms of A2 into SMMC-7721 cells. A2 increased the mRNA expression of OATP1B3 (an organic anion-transporting polypeptide) and uptake of A2 was inhibited by rifampin (inhibitor of OATP1B3), which indicated that the transporter-mediated transport of A2 was mediated by OATP1B3. In addition, according to the western blot and apoptosis assays, we found that A2 killed SMMC-7721 cells by inducing cell apoptosis mainly via an AIF (apoptosis-inducing factor) pathway and a caspase-dependent mitochondria apoptosis pathway.