Glutamine provides carbon and nitrogen to support the proliferation of cancer cells. However, the precise reason why cancer cells are particularly dependent on glutamine remains unclear. In this study, we report that glutamine modulates the tumor suppressor F-box and WD repeat domain-containing 7 (FBW7) to promote cancer cell proliferation and survival. Specifically, lysine 604 (K604) in the sixth of the 7 substrate-recruiting WD repeats of FBW7 undergoes glutaminylation (Gln-K604) by glutaminyl tRNA synthetase. Gln-K604 inhibits SCFFBW7-mediated degradation of c-Myc and Mcl-1, enhances glutamine utilization, and stimulates nucleotide and DNA biosynthesis through the activation of c-Myc. Additionally, Gln-K604 promotes resistance to apoptosis by activating Mcl-1. In contrast, SIRT1 deglutaminylates Gln-K604, thereby reversing its effects. Cancer cells lacking Gln-K604 exhibit overexpression of c-Myc and Mcl-1 and display resistance to chemotherapy-induced apoptosis. Silencing both c-MYC and MCL-1 in these cells sensitizes them to chemotherapy. These findings indicate that the glutamine-mediated signal via Gln-K604 is a key driver of cancer progression and suggest potential strategies for targeted cancer therapies based on varying Gln-K604 status.
Glutamine/metabolism* ; Myeloid Cell Leukemia Sequence 1 Protein/genetics* ; Humans ; Proto-Oncogene Proteins c-myc/genetics* ; Cell Proliferation ; Signal Transduction ; Neoplasms/pathology* ; F-Box-WD Repeat-Containing Protein 7/genetics* ; Cell Survival ; Cell Line, Tumor ; Apoptosis

The plant F-box protein more axillary growth 2 (MAX2) is a key factor in the signal transduction of strigolactones (SLs) and karrinkins (KARs). As the main component of the SKP1-CUL1-FBX (SCF) complex ubiquitin ligase E3, MAX2 is responsible for specifically recognizing the target proteins, suppressor of MAX2 1/SMAX1-like proteins (SMAX1/SMXLs), which would be degraded after ubiquitination. It can thereby regulate plant morphogenesis and stress responses. There exist homologous genes of MAX2 in the important grain and oil crop soybean (Glycine max). However, its role in plant defense responses has not been investigated yet. Here, GmMAX2b, a homologous gene of MAX2, was successfully cloned from stressed soybean. Bioinformatics analysis revealed that there were two MAX2 homologous genes, GmMAX2a and GmMAX2b, with a similarity of 96.2% in soybean. Their F-box regions were highly conserved. The sequence alignment and cluster analysis of plant MAX2 homologous proteins basically reflected the evolutionary relationship of plants and also suggested that soybean MAX2 might be a multifunctional protein. Expression analysis showed that plant pathogen infection and salicylic acid treatment induced the expression of GmMAX2b in soybean, which is consistent with that of MAX2 in Arabidopsis. Ectopic expression of GmMAX2b compensated for the susceptibility of Arabidopsis max2-2 mutant to pathogen, indicating that GmMAX2b positively regulated plant disease resistance. In addition, yeast two hybrid technology was used to explore the potential target proteins of GmMAX2b. The results showed that GmMAX2b interacted with SMXL6 and weakly interacted with SMXL2. In summary, GmMAX2b is a positive regulator in plant defense responses, and its expression is induced by pathogen infection and salicylic acid treatment. GmMAX2b might exert its effect through interaction with SMXL6 and SMXL2. This study expands the theoretical exploration of soybean disease resistant F-box and provides a scientific basis for future soybean disease resistant breeding.
Glycine max/metabolism* ; Disease Resistance/genetics* ; Plant Diseases/immunology* ; Plant Proteins/genetics* ; Cloning, Molecular ; Gene Expression Regulation, Plant ; F-Box Proteins/genetics* ; Arabidopsis/genetics* ; Phylogeny

Mesenchymal stem cells (MSCs) are characterized by their self-renewing capacity and differentiation potential into multiple tissues. Thus, management of the differentiation capacities of MSCs is important for MSC-based regenerative medicine, such as craniofacial bone regeneration, and in new treatments for metabolic bone diseases, such as osteoporosis. In recent years, histone modification has been a growing topic in the field of MSC lineage specification, in which the Su(var)3-9, enhancer-of-zeste, trithorax (SET) domain-containing family and the Jumonji C (JmjC) domain-containing family represent the major histone lysine methyltransferases (KMTs) and histone lysine demethylases (KDMs), respectively. In this review, we summarize the current understanding of the epigenetic mechanisms by which SET domain-containing KMTs and JmjC domain-containing KDMs balance the osteogenic and adipogenic differentiation of MSCs.
Adipogenesis ; genetics ; physiology ; Cell Differentiation ; genetics ; physiology ; Cell Lineage ; genetics ; Epigenesis, Genetic ; genetics ; F-Box Proteins ; genetics ; physiology ; Histone Demethylases ; genetics ; physiology ; Histone-Lysine N-Methyltransferase ; genetics ; physiology ; Humans ; Jumonji Domain-Containing Histone Demethylases ; genetics ; physiology ; Mesenchymal Stromal Cells ; enzymology ; physiology ; Methyltransferases ; genetics ; physiology ; Osteogenesis ; genetics ; physiology

OBJECTIVETo evaluate the expression of FBXW7 in esophageal squamous cell carcinoma (ESCC) and to explore the correlation of FBXW7 expression with clinicopathologic features and prognosis of ESCC.

METHODSNinety cases of ESCC and twenty cases of tumor-adjacent normal tissues and forty intraepithelial neoplasia tissues were detected by immunohistochemistry methods. The expression of FBXW7 in 40 surgical ESCC tissues and tumor-adjacent normal tissues was detected by Western blotting and RT-PCR. The relationship between the expression of FBXW7, clinicopathological characteristics and prognosis was analyzed.

RESULTSThe positive rate of FBXW7 protein was significantly lower in the ESCC and high-grade intraepithelial neoplasia tissues than in the tumor-adjacent normal tissues and low grade intraepithelial neoplasia tissues (40.0% and 33.3% vs. 85.0% and 77.3%, χ² = 21.923, P < 0.001). The FBXW7 protein was down-regulated in ESCC tissues (P < 0.05), whereas the FBXW7 mRNA was down-regulated in ESCC tissues compared with that in the paracancerous tissues. The expression of FBXW7 was significantly correlated with TNM stage, degree of differentiation, invasion depth and lymph node metastasis (χ² =9.643, 14.908, 16.294, 10.222, respectively, P = 0.002, 0.001, 0.000, 0.001). In the ninety patients, the 5-year survival rates of cases with positive and negative expression of FBXW7 protein was 67.6% and 39.3%, respectively (χ² =6.699, P = 0.01).

CONCLUSIONSThe results of this study demonstrate that FBXW7 expression is significantly declined in ESCC and high grade intraepithelial neoplasia tissues, and is closely correlated with poor prognosis of this disease. FBXW7 as a tumor suppressor gene may play an important role in the carcinogenesis, development and metastasis of ESCC. These results suggest that FBXW7 may become a valuable marker for the severity and prognosis in ESCC.

Biomarkers, Tumor ; metabolism ; Blotting, Western ; Carcinoma, Squamous Cell ; diagnosis ; metabolism ; Cell Cycle Proteins ; genetics ; Down-Regulation ; Esophageal Neoplasms ; diagnosis ; metabolism ; F-Box Proteins ; genetics ; F-Box-WD Repeat-Containing Protein 7 ; Humans ; Immunohistochemistry ; Lymphatic Metastasis ; Neoplasm Staging ; Prognosis ; RNA, Messenger ; Survival Rate ; Ubiquitin-Protein Ligases ; genetics

Aged ; Cognition Disorders ; genetics ; F-Box Proteins ; genetics ; HSP40 Heat-Shock Proteins ; genetics ; Humans ; Male ; Monocytes ; metabolism ; Parkinson Disease ; genetics ; alpha-Synuclein ; genetics

Animals ; Carcinogenesis ; Cell Cycle Proteins ; genetics ; metabolism ; Cyclin E ; metabolism ; F-Box Proteins ; genetics ; metabolism ; F-Box-WD Repeat-Containing Protein 7 ; Gene Silencing ; Genes, Tumor Suppressor ; Humans ; Mutation ; Myeloid Cell Leukemia Sequence 1 Protein ; metabolism ; Neoplasms ; genetics ; metabolism ; pathology ; Proto-Oncogene Proteins c-myc ; metabolism ; Receptors, Notch ; metabolism ; Signal Transduction ; TOR Serine-Threonine Kinases ; metabolism ; Ubiquitin-Protein Ligases ; genetics ; metabolism

OBJECTIVETo explore the interaction between SerpinB5 and MAFbx in gastric cancer cell and to identify the interaction sites.

METHODSThe interaction between SerpinB5 and MAFbx was screened and validated by yeast two-hybrid screening and co-immunoprecipitation. The expression of MAFbx was analyzed after SerpinB5 expression being modified by RNA interference and pGBKT7-SerpinB5 transfection. The impact of SerpinB5 on the expression of MAFbx was studied in gastric cancer cell line SUN-16. A model of MAFbx was constructed by homology modeling. The related residues for interaction were analyzed by Autodock4.0.

RESULTSThe interaction between SerpinB5 and MAFbx was validated. The expression of MAFbx changed along with SerpinB5 expression. Amino acids including PRO261, ASN361, and LYS362 were key residue in the interaction of SerpinB5 and MAFbx.

CONCLUSIONSerpinB5 interacts with MAFbx in gastric cancer cell. Amino acids including PRO261, ASN361, and LYS362 are potential binding sites.

Cell Line, Tumor ; Humans ; Immunoprecipitation ; Muscle Proteins ; genetics ; metabolism ; RNA Interference ; SKP Cullin F-Box Protein Ligases ; genetics ; metabolism ; Serpins ; genetics ; metabolism ; Stomach Neoplasms ; genetics ; metabolism ; Two-Hybrid System Techniques

BACKGROUNDParkinson's disease (PD) is an autosomally inherited neurodegenerative disease in elderly people. The etiology of PD has long been thought to be associated with both genetic and environmental factors. To explore potential genetic risk factors for PD in the northern Han Chinese population, we investigated three single nucleotide polymorphisms (SNPs) (rs4538475, rs11107 and rs12564040) in the BST1, PARK15 and PARK9 genes.

METHODSGenomic DNA from 215 PD patients and 212 matched controls was amplified in two independent PCR systems and subsequently genotyped by digestion with the endonuclease PstI. Genetic parameter and association studies were carried out with SPSS 13.0 and PLINK 1.07 software.

RESULTSWe could accurately detect all genotypes in the three loci with the PCR-RFLP or mismatched PCR-RFLP techniques. The observed heterozygosities of the rs4538475 and rs11107 loci in PD and control groups ranged from 0.460 - 0.481 and 0.410 - 0.441, in BST1, PARK15 respectively, while we detected no heterozygosity at the rs12564040 locus in PARK9. The similar distributions of genotypic frequency between both groups suggest that the three SNPs investigated in this study are unlikely to play roles as common risk factors or pathogenic mutations for PD in northern Han Chinese.

CONCLUSIONThe SNPs investigated in the BST1, PARK15 and PARK9 genes associated with PD susceptibility are not associated with PD in the northern Han Chinese population.

ADP-ribosyl Cyclase ; genetics ; Adult ; Aged ; Aged, 80 and over ; Antigens, CD ; genetics ; Asian Continental Ancestry Group ; genetics ; F-Box Proteins ; genetics ; Female ; GPI-Linked Proteins ; genetics ; Genetic Predisposition to Disease ; genetics ; Humans ; Male ; Middle Aged ; Parkinson Disease ; genetics ; Parkinsonian Disorders ; genetics ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Polymorphism, Single Nucleotide ; genetics ; Young Adult

OBJECTIVETo study muscle atrophy F-box (MAFbx) and muscle ring finger 1 (MuRF1) mRNA expression and its relationship with muscular contraction following free muscle transfer.

METHODSThe gracilis muscle was orthotopic transferred in adult rat to establish the animal model. The muscle at the unoperated side was used as control. The expression of MAFbx and MuRF1 mRNA, the muscle contraction and muscle function were measured by real-time PCR and multiple function physiological device. The relationship among the expression of MAFbx and MuRF1 mRNA, the muscle contraction and muscle function was analyzed.

RESULTSAfter muscle free transfer, muscle wet weight reservation, the maximum contraction and tetanus strength reduce first and increased later, but still lower than those at control side. The expression of MAFbx and MuRF1 mRNA reached peak level 3 - 4 weeks after muscle transfer which was 7.1 and 4.1 times as that at control side. It decreased later, but still higher than that at control side, showing a significant difference between them (P< 0. 05).

CONCLUSIONSPersistent over-expression of MAFbx and MuRF1 mRNA after muscle transfer has a close relationship with muscle atrophy and muscle dysfunction. MAFbx and MuRF1 can be used as markers for early muscle atrophy, and also as potential target for drug treatment of muscle atrophy.

Animals ; Female ; Muscle Contraction ; Muscle Proteins ; genetics ; Muscle, Skeletal ; pathology ; Muscular Atrophy ; genetics ; metabolism ; pathology ; RING Finger Domains ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley ; SKP Cullin F-Box Protein Ligases ; genetics ; Tripartite Motif Proteins ; Ubiquitin-Protein Ligases ; genetics

OBJECTIVETo investigate the protective effect of Atrogin-1 gene silencing via RNA interference technique on a model of muscle cell malnutrition.

METHODSSequences of five target Atrogin-1 siRNA and the control were selected and synthesized and cloned to vector pBS-hU6-I and then to vector FG12. The length and rightness of the sequences were confirmed. The recombinant FG12 vectors were cotransfected along with pRSVREV, pMDLg/pRRE and pHCMV-G into 293T cells to package lentivirus particles, with which C2C12 cells were infected. The infected C2C12 cells were cultured and differentiated to form myotubes before TNF-alpha was added to induce malnutrition. Expressed products of Atrogin-1 of myotubes were identified by real time PCR and Western blot methods. Myotubes were observed and photographed directly in culture plate without fixation.

RESULTSThe length and sequences of inserted DNA were right. Compared with the RNA interferencing group, significant atrophy and upregulated expression of Atrogin-1 of myotubes treated by TNF-alpha was found in the control group.

CONCLUSIONAtrogin-1 gene silencing could be used to inhibit malnutrition of muscle cells caused by TNF-alpha. Atrogin-1 could be an ideal target in the treatment of cancer cachexia.

Animals ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Gene Silencing ; Genetic Vectors ; Lentivirus ; genetics ; Mice ; Muscle Cells ; cytology ; drug effects ; metabolism ; Muscle Proteins ; genetics ; RNA, Small Interfering ; genetics ; SKP Cullin F-Box Protein Ligases ; genetics ; Transfection ; Tumor Necrosis Factor-alpha ; pharmacology