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2.
Cancer Lett ; 586: 216707, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38331088

ABSTRACT

Cyclic GMP-AMP synthase (cGAS), promotes non-small cell lung cancer (NSCLC) cell proliferation. However, the specific mechanisms of cGAS-mediated NSCLC cell proliferation are largely unknown. In this study, we found asymmetric dimethylation by protein arginine methyltransferase 1 (PRMT1) at R127 of cGAS. This facilitated the binding of deubiquitinase USP7 and contributed to deubiquitination and stabilization of cGAS. PRMT1-and USP7-dependent cGAS stability, which also played a pivotal role in accelerating NSCLC cell proliferation through activating AKT pathway. We validated that the expression of cGAS and PRMT1 were positive correlated in human non-small cell lung cancer samples. Our study demonstrates a unique mechanism for managing cGAS stability by arginine methylation and indicates that PRMT1-cGAS-USP7 axis is a potential therapeutic target for NSCLC.


Subject(s)
Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Humans , Arginine , Carcinoma, Non-Small-Cell Lung/genetics , Cell Proliferation , Lung Neoplasms/genetics , Methylation , Protein-Arginine N-Methyltransferases/genetics , Protein-Arginine N-Methyltransferases/metabolism , Repressor Proteins/metabolism , Ubiquitin-Specific Peptidase 7/metabolism
3.
Int J Biol Macromol ; 254(Pt 2): 127827, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37926314

ABSTRACT

The interaction between starch and protein during food processing is crucial for controlling food quality. This study aims to understand the interactions between corn starch and black bean protein isolate (BBPI) at various gelatinization phases and their effects on the physicochemical properties of the blends. BBPI reduced the rheological properties of the corn starch/BBPI mixed system during gelatinization, increasing light transmittance and gelatinization temperature, while decreasing total viscosity and enthalpy change. The changes in starch and protein microstructure during gelatinization indicated that BBPI adhered to the starch particle surface or partially penetrated the swollen starch particles. Fourier transform infrared spectroscopy (FT-IR) revealed that BBPI decreased the number of hydrogen bonds within starch, with no newly formed functional groups in the mixed system. Furthermore, BBPI reduced the composite relative crystallinity (RC). The effect of protein addition on water migration in the mixed system demonstrates that protein and starch compete for water during gelatinization, preventing water molecules from diffusing into starch particles.


Subject(s)
Starch , Zea mays , Starch/chemistry , Zea mays/chemistry , Spectroscopy, Fourier Transform Infrared , Temperature , Viscosity , Water/chemistry
4.
Foods ; 12(10)2023 May 12.
Article in English | MEDLINE | ID: mdl-37238784

ABSTRACT

Modification of corn starch using ultrasonic waves to improve its freeze-thaw resistance in frozen model doughs and buns. Analysis was performed by rheometry, low-field-intensity nuclear magnetic resonance imaging, Fourier infrared spectroscopy, and scanning electron microscopy. The results showed that the addition of ultrasonically modified corn starch reduced the migration of water molecules inside the model dough, weakened the decrease of elastic modulus, and enhanced the creep recovery effect; the decrease in α-helical and ß-fold content in the model dough was reduced, the destruction of internal network structure was decreased, the exposed starch granules were reduced, and the internal interaction of the dough was enhanced; the texture of the buns became softer and the moisture content increased. In conclusion, ultrasound as a physical modification means can significantly improve the freeze-thaw properties of corn starch, providing new ideas for the development and quality improvement of corn-starch-based instant frozen pasta products.

5.
Biometrics ; 79(2): 1000-1013, 2023 06.
Article in English | MEDLINE | ID: mdl-35426133

ABSTRACT

In observational cohort studies with complex sampling schemes, truncation arises when the time to event of interest is observed only when it falls below or exceeds another random time, that is, the truncation time. In more complex settings, observation may require a particular ordering of event times; we refer to this as sequential truncation. Estimators of the event time distribution have been developed for simple left-truncated or right-truncated data. However, these estimators may be inconsistent under sequential truncation. We propose nonparametric and semiparametric maximum likelihood estimators for the distribution of the event time of interest in the presence of sequential truncation, under two truncation models. We show the equivalence of an inverse probability weighted estimator and a product limit estimator under one of these models. We study the large sample properties of the proposed estimators and derive their asymptotic variance estimators. We evaluate the proposed methods through simulation studies and apply the methods to an Alzheimer's disease study. We have developed an R package, seqTrun, for implementation of our method.


Subject(s)
Alzheimer Disease , Models, Statistical , Humans , Survival Analysis , Computer Simulation , Probability
6.
Int J Mol Sci ; 23(3)2022 Feb 04.
Article in English | MEDLINE | ID: mdl-35163710

ABSTRACT

Cytoplasmic chromatin fragments (CCF) are recognized by the cytoplasmic DNA sensor cyclic GMP-AMP synthase (cGAS), which activates the cGAS-STING (cyclic GMP-AMP synthase-stimulator of interferon genes) pathway and promotes the production of inflammatory factors and breast cancer metastasis. However, the mechanisms by which CCF are formed in tumor cells and CCF activation cGAS promotes breast cancer metastasis remain unclear. Here, we report that the enhancer of zeste homolog 2 (EZH2) can promote the formation of CCF and activate the cGAS-STING pathway to promote breast cancer metastasis. Further research found that the EZH2-mediated CCF formation depended on high mobility group A1 (HMGA1), while the stability of EZH2 required ubiquitin-specific peptidase 7 (USP7), indicating that the EZH2-HMGA1-USP7 complex regulated CCF formation. Moreover, EZH2 can activate cGAS through CCF, requiring USP7 to deubiquitinate cGAS and stabilize cGAS. In vivo experimental results showed that EZH2 could promote breast cancer metastasis through CCF. Our findings highlight a new target for breast cancer metastasis. Targeting the EZH2-CCF-cGAS axis may be a potential therapeutic strategy for inhibiting breast cancer metastasis.


Subject(s)
Breast Neoplasms , Chromatin , Enhancer of Zeste Homolog 2 Protein , Nucleotidyltransferases , Breast Neoplasms/genetics , Chromatin/genetics , Enhancer of Zeste Homolog 2 Protein/genetics , Enhancer of Zeste Homolog 2 Protein/metabolism , Female , HMGA1a Protein/metabolism , Humans , Melanoma , Membrane Proteins/genetics , Membrane Proteins/metabolism , Nucleotidyltransferases/genetics , Nucleotidyltransferases/metabolism , Signal Transduction , Skin Neoplasms , Ubiquitin-Specific Peptidase 7 , Melanoma, Cutaneous Malignant
7.
IEEE Trans Pattern Anal Mach Intell ; 44(8): 4355-4373, 2022 Aug.
Article in English | MEDLINE | ID: mdl-33656988

ABSTRACT

Low-rank tensor recovery (LRTR) is a natural extension of low-rank matrix recovery (LRMR) to high-dimensional arrays, which aims to reconstruct an underlying tensor X from incomplete linear measurements [Formula: see text]. However, LRTR ignores the error caused by quantization, limiting its application when the quantization is low-level. In this work, we take into account the impact of extreme quantization and suppose the quantizer degrades into a comparator that only acquires the signs of [Formula: see text]. We still hope to recover X from these binary measurements. Under the tensor Singular Value Decomposition (t-SVD) framework, two recovery methods are proposed-the first is a tensor hard singular tube thresholding method; the second is a constrained tensor nuclear norm minimization method. These methods can recover a real n1×n2×n3 tensor X with tubal rank r from m random Gaussian binary measurements with errors decaying at a polynomial speed of the oversampling factor λ:=m/((n1+n2)n3r). To improve the convergence rate, we develop a new quantization scheme under which the convergence rate can be accelerated to an exponential function of λ. Numerical experiments verify our results, and the applications to real-world data demonstrate the promising performance of the proposed methods.

8.
Oncogene ; 40(20): 3548-3563, 2021 05.
Article in English | MEDLINE | ID: mdl-33927350

ABSTRACT

Mitochondrial oxidative phosphorylation (OXPHOS) is a vital regulator of tumor metastasis. However, the mechanisms governing OXPHOS to facilitate tumor metastasis remain unclear. In this study, we discovered that arginine 21(R21) and lysine 108 (K108) of mitochondrial ribosomal protein S23 (MRPS23) was methylated by the protein arginine methyltransferase 7 (PRMT7) and SET-domain-containing protein 6 (SETD6), respectively. R21 methylation accelerated the poly-ubiquitin-dependent degradation of MRPS23 to a low level. The MRPS23 degradation inhibited OXPHOS with elevated mtROS level, which consequently increased breast cancer cell invasion and metastasis. In contrast, K108 methylation increased MRPS23 stability, and K108 methylation coordinated with R21 methylation to maintain a low level of MRPS23, which was in favor of supporting breast cancer cell survival through regulating OXPHOS. Consistently, R21 and K108 methylation was correlated with malignant breast carcinoma. Significantly, our findings unveil a unique mechanism of controlling OXPHOS by arginine and lysine methylation and point to the impact of the PRMT7-SETD6-MRPS23 axis during breast cancer metastasis.


Subject(s)
Arginine/chemistry , Breast Neoplasms/metabolism , Lysine/chemistry , Mitochondria/metabolism , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Cell Line, Tumor , Cell Proliferation/physiology , Female , Humans , Methylation , Mitochondria/pathology , Neoplasm Metastasis , Organoids , Oxidative Phosphorylation , Protein Methyltransferases/genetics , Protein Methyltransferases/metabolism , Protein Processing, Post-Translational , Protein-Arginine N-Methyltransferases/genetics , Protein-Arginine N-Methyltransferases/metabolism
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