Transglutaminase 2 serves as a pathogenic hub gene of KRAS mutant colon cancer based on integrated analysis

BACKGROUND Colon cancer is acknowledged as one of the most common malignancies worldwide,ranking third in United States regarding incidence and mortality.Notably,approximately 40%of colon cancer cases harbor oncogenic KRAS mutations,resulting in the continuous activation of epidermal growth factor receptor signaling.AIM To investigate the key pathogenic genes in KRAS mutant colon cancer holds considerable importance.METHODS Weighted gene co-expression network analysis,in combination with additional bioinformatics analysis,were conducted to screen the key factors driving the progression of KRAS mutant colon cancer.Meanwhile,various in vitro experiments were also conducted to explore the biological function of transglutaminase 2(TGM2).RESULTS Integrated analysis demonstrated that TGM2 acted as an independent prognostic factor for progression-free survival.Immunohistochemical analysis on tissue microarrays revealed that TGM2 was associated with an elevated probability of perineural invasion in patients with KRAS mutant colon cancer.Additionally,biological roles of the key gene TGM2 was also assessed,suggesting that the downregulation of TGM2 attenuated the proliferation,invasion,and migration of the KRAS mutant colon cancer cell line.CONCLUSION This study underscores the potential significance of TGM2 in the progression of KRAS mutant colon cancer.This insight not only offers a theoretical foundation for therapeutic approaches but also highlights the need for additional clinical trials and fundamental research to support our preliminary findings.

Development and Physical Properties of Film of Wheat Gluten Cross-linked by Transglutaminase

Films were developed from the modified wheat glutens by microbial transglutamina se(MTGase, [E/S]=10u/g,15u/g and 20u/g) in order to improve physical and barri er properties of the films.Glycerol was used as a plasticizer.The films prepared from the modified-glutens by MTGase show a lower elongation at break(E) and a water vapor permeability(WVP), and a higher tensile strength(TS) than the nati ve gluten films.When the modified gluten films by different concentrations of MT Gase are immersed in water at 25℃,their weight losses decreased significantly, and their water resistance increases obviously as expected, compared with the c ontrol gluten films. Moreover, an addition of glycerol as plasticizer greatly mo dified water vapor barrier and mechanical properties of the films.

Microbial transglutaminase should be considered as an environmental inducer of celiac disease

Due to the recent interest in food additives that can act as triggering factors in autoimmune diseases including celiac disease(CD),the present letter to the editor expands on the microbial transglutaminase(mTG).It is heavily consumed by a plethora of food processing industries as“glue of proteins”thus improving product’s stability,texture and shelf life.However,more and more information is accumulated lately,questioning its safety.Its cross-linked gliadin complexes are immunogenic in CD.The enzyme increases gliadin uptake,is transported in a trans-epithelial way and deposited below the enterocyte’s line,has antiphagocytic activity,enhances intestinal permeability and creates luminal resistant isopeptide bonds.No doubt that mTG is beneficial to food industries but a caveat to public health is highly recommended.

Erythrocytic transglutaminase inhibition hemolysis at presentation of celiac disease

Celiac disease (CD) is a common autoimmune condition.Previously it was considered to be a rare childhood disorder,but is actually considered a relatively common condition,present at any age,which may have multiple complications and manifestations.Hematological disorders of the disease are not uncommon.Among these disorders,the most frequently reported are anemias as a result of iron deficiency,often associated with folate and/or B12 deficiency.Anemias caused by hemolysis are very rarely reported in celiac patients.An 11-year-old girl with a previous uneventful medical history presented with severe hemolytic anemia.Hemolysis was Coombs negative,accompanied by inappropriate low reticulocyte count,despite exaggerated bone marrow hyperplasia of the erythroid precursors which showed normal maturation.Serology for recent infections,including EpsteinBarr virus,parvovirus B19,cytomegalovirus and mycoplasma,were all negative.Levels of serum IgA,IgG and IgM,were all within normal ranges for age.Screeningfor anti-DNA,antinuclear,antineutrophil cytoplasmic,antimicrosomal,antithyroglobulin,and antimitochondrial antibodies and lupus anticoagulants,was negative.She was also negative for human immunodeficiency virus.Conventional therapy with corticosteroids and intravenous immunoglobulin failed.CD was serendipitously discovered upon screening for anti-tissue transglutaminase autoantibodies.The disease was confirmed by biopsy of the small intestine mucosa.The patient recovered with gluten-free diet.A unique case of CD is presented.CD should be serologically screened in each patient with Coombs negative "immune"hemolytic anemia,particularly if accompanied by "reticulocytopenia".A new hemolytic mechanism and very speculative explanation for "reticulocytopenia"are discussed.

Duodenal biopsy may be avoided when high transglutaminase antibody titers are present

AIM:To evaluate the predictive value of tissue transglutaminase (tTG) antibodies for villous atrophy in adult and pediatric populations to determine if duodenal biopsy can be avoided.METHODS: A total of 324 patients with celiac disease (CD; 97 children and 227 adults) were recruited prospectively at two tertiary centers. Human IgA class anti-tTG antibody measurement and upper gastrointestinal endoscopy were performed at diagnosis. A second biopsy was performed in 40 asymptomatic adults on a gluten-free diet (GFD) and with normal tTG levels.RESULTS: Adults showed less severe histopathology (26% vs 63%, P<0.0001) and lower tTG antibody titers than children. Levels of tTG antibody correlated with Marsh type in both populations (r=0.661, P<0.0001). Multiple logistic regression revealed that only tTG antibody was an independent predictor for Marsh type 3 lesions, but clinical presentation type and age were not. A cut-off point of 30 U tTG antibody yielded the highest area under the receiver operating characteristic curve (0.854). Based on the predictive value of this cut-off point, up to 95% of children and 53% of adults would be correctly diagnosed without biopsy. Despite GFDs and decreased tTG antibody levels, 25% of the adults did not recover from villous atrophy during the second year after diagnosis.CONCLUSION: Strongly positive tTG antibody titers might be sufficient for CD diagnosis in children. However, duodenal biopsy cannot be avoided in adults because disease presentation and monitoring are different.

Inhibitory Effect of Tissue Transglutaminase (tTG) Antisense Oligodeoxynucleotides on tTG Expression in Cultured Bovine Trabecular Meshwork Cells

To study the effect of tTG fully phosphorothioated antisense oligodeoxynucleotides （tTG-ASDON） on tTG expression in cultured bovine trabecular meshwork cells （BTMCs） in vitro and explore a new treatment alternative for primary open angle glaucoma （POAG）, the ASDON1 and ASDON2 complementary to the protein codogram region of tTG were designed, synthesized and phosphorothioated according to the secondary structure of tTG. The ASDON1 and ASDON2 were embedded in Lipofectamine and transfected into BTMCs. The untreated group served as negative controls. The expression of tTG in the mRNA and protein level were measured by semi-quantitative RT-PCR and immunohistochemical technique-Supervision method respectively. Our results showed that both the mRNA and the protein of tTG with tTG-ASDON1 and tTCr-ASDON2 were significantly decreased as compared with that of the controls （P〈0.05）. On the other hand, no significant difference was found between the ASDON1 group and the ASDON2 group. It is concluded that the expression of tTG mRNA and protein in cultured BTMC are down-regulated by tTG- ASDON. As a result, tTG-ASDON may be used for the treatment of POAG through the inhibitory effect on the expression of tTG.

Cystamine ameliorates liver fibrosis induced by carbon tetrachloride via inhibition of tissue transglutaminase

AIM： To investigate the anti-fibrosis effect of the tissue transglutarninase （tTG） specific inhibitor cystarnine on liver fibrosis. METHODS： Sixty-eight male Sprague Dawley rats were divided into three groups： normal control, liver fibrosis control and cystamine-treated group. Liver fibrosis was induced by intraperitoneal injection of carbon tetrachloride （CCl4）, and Cystarnine was administrated by intraperitoneal injection starting 2 d before the first administration of CCl4. Animals in each group were further divided into 2 subgroups according to two time points of 4 wk and 8 wk after treatment. Hepatic function, pathological evaluation （semi-quantitative scoring system, SSS） and liver hydroxyproline （Hyp） content were examined. Real-time PCR was used to detect the expression of tTG, smooth muscle alpha actin （α-SMA）, tissue inhibitor of metalloproteinase 1 （TIMP-1） and collagen-1 mRNA. The expressions of tTG and α-SMA protein were detected by Western Blotting. RESULTS： Eight weeks after treatment, the SSS score of liver was significantly less in the cystamine group than that in the fibrosis control group （P 〈 0.01）. The levels of alanine arninotransferase （ALT） and total bile acid （TBA） at the 4 wk and 8 wk time points were decreased in the cystamine group compared with those in fibrosis controls （P 〈 0.01）. Liver hydroxyproline content at the 4 wk and 8 wk time points showed a substantial reduction in the cystamine group compared to fibrosis controls （P 〈 0.01）. The expression of tTG, α-SMA, collagen-1, TIMP-1 mRNA and tTG, as well as α-SMA protein was downregulated in the cystamine group compared to fibrosis controls. CONCLUSION： Cystamine can ameliorate CCl4 induced liver fibrosis and protect hepatic function. The possible mechanism is related to the reduced synthesis of the extracellular matrix （ECM） caused by the inhibition of hepatic stellate cell activation and decreased expression of TIMP-1.

The Impact of Microbial Transglutaminase on the Quality and Antioxidant Activity of Camel-Milk Soft Cheese

This study aimed at investigating the impact of adding microbial transglutaminase (MTGase) after rennet addition on some properties of fresh soft cheese made from camel milk. MTGase was added to milk at concentration of 80, 100 and 120 U/L after 20 and 30 min of renneting. The chemical composition, yield, hardness, antioxidant activity and sensory properties of cheese were estimated. Enzymatic protein crosslinking was analyzed by SDS-PAGE. Results revealed that MTGase-treated cheeses were higher in moisture and lower in protein content compared to control. In addition, the concentration of MTGase and time of addition significantly (P 0.05) impacted these parameters. Among treated cheeses, samples with 80 U of MTGase and addition time of 20 min were the highest in total solids and protein content. Adding MTGase significantly (P 0.05) increased the cheese yield, however, increased MTGase concentration at any time of addition did not improve it. The electrophoretic patterns of MTGase-cheese proteins showed a reduction in the intensity of caseins bands and the appearance of new protein fractions with high molecular weights. However, the changes in the intensity of the whey proteins bands were not sufficiently clear as caseins. The cheese hardness was significantly (P 0.05) affected by adding MTGase. Cheese containing 80 U of MTGase had the highest hardness value compared to control and other treated samples. The antioxidant activity of cheese was negatively influenced by adding the enzyme. The use of MTGase enhanced the mouthfeel, texture and overall acceptability of cheese. However, the effect of MTGase concentration and addition time was not significant (P > 0.05) on the sensory attributes. In conclusion, adding MTGase to milk at concentration of 80 U after 20 min of renneting is recommended to improve the yield, textural and some sensory properties of fresh soft cheese made from camel milk.

Transglutaminase 3 expression in C57BL/6J mouse embryo epidermis and the correlation with its differentiation

Epidermal-type transglutaminase 3 (TGM3) is involved in the cross-linking of structural proteins to form the cornifiedenvelope in the epidermis. In the present study, we detected the expression of TGM3 in the mouse embryo using RT-PCR.TGM3 mRNA is weakly presented from E11.5 to E14.5 and increases significantly from E15.5 to birth. Then wedetermined the spatial and temporal expression pattern of TGM3 in the skin and other organs by in situ hybridization. Wefound a deprivation of TGM3 in skin at E11.5, while a rich supply in periderm cells and a weak expression in basal cellsfrom E12.5 to E14.5. From the period of E15.5 to E16.5, after keratinization in the epidermis, TGM3 was expressed inthe granular and cornified layers. The electron microscopic observation of the C57BL/6J mouse limb bud skin develop-ment provided several morphological evidences for the epidermal differentiation. The above findings suggest that theexpression of TGM3 plays a important role in the epidermis differentiation in embryogenesis.

Transglutaminase inhibition:A therapy to protect cells from death in neurodegeneration?

Transglutaminases(TGs;E.C.2.3.2.13)are ubiquitous enzymes which catalyze post-translational modifications of proteins.TGs and TG-catalyzed post-translational modifications of proteins have been shown to be involved in the molecular mechanisms responsible for several human diseases.In particular,TG activity has been hypothesized to also be involved also in the molecular mechanisms responsible for human neurodegenerative diseases.In support of this hypothesis,Basso et al recently demonstrated that the TG inhibition protects against oxidative stress-induced neuronal death,suggesting that multiple TG isoforms participate in oxidative stress-induced cell death and that nonselective TG isoform inhibitors will be most effective in fighting oxidative death in neurological disorders.In this commentary,we discuss the possible molecular mechanisms by which TG activity could be involved in the pathogenesis of neurological diseases,with particular reference to neurodegenerative diseases,and the possible involvement of multiple TG isoforms expressed simultaneously in the nervous system in these diseases.Moreover,therapeutic strategies based on the use of selective or nonselective TG inhibitors for the amelioration of thesymptoms of patients with neurological diseases,characterized by aberrant TG activity,are also discussed.

Physio-pathological roles of transglutaminase-catalyzed reactions

Transglutaminases(TGs) are a large family of related and ubiquitous enzymes that catalyze post-translational modifications of proteins.The main activity of these enzymes is the cross-linking of a glutaminyl residue of a protein/peptide substrate to a lysyl residue of a protein/peptide co-substrate.In addition to lysyl residues,other second nucleophilic co-substrates may include monoamines or polyamines(to form mono-or bi-substituted/crosslinked adducts) or-OH groups(to form ester linkages) .In the absence of co-substrates,the nucleophile may be water,resulting in the net deamidation of the glutaminyl residue.The TG enzymes are also capable of catalyzing other reactions important for cell viability.The distribution and the physiological roles of TG enzymes have been widely studied in numerous cell types and tissues and their roles in several diseases have begun to be identified."Tissue" TG(TG2) ,a member of the TG family of enzymes,has definitely been shown to be involved in the molecular mechanisms responsible for a very widespread human pathology:i.e.celiac disease(CD) .TG activity has alsobeen hypothesized to be directly involved in the pathogenetic mechanisms responsible for several other human diseases,including neurodegenerative diseases,which are often associated with CD.Neurodegenerative diseases,such as Alzheimer's disease,Parkinson's disease,supranuclear palsy,Huntington's disease and other recently identified polyglutamine diseases,are characterized,in part,by aberrant cerebral TG activity and by increased cross-linked proteins in affected brains.In this review,we discuss the physio-pathological role of TG-catalyzed reactions,with particular interest in the molecular mechanisms that could involve these enzymes in the physio-pathological processes responsible for human neurodegenerative diseases.

Overexpression of transglutaminase 4 and prostate cancer progression： a potential predictor of less favourable outcomes

Transglutaminase 4 has been shown to enhance various biological properties of prostate cancer cells, e.g., cell-matrix adhesion, invasiveness and the epithelial-mesenchymal transition. The objectives of this study were to investigate the associations between transglutaminase 4 expression and the established features and biochemical recurrence of prostate cancer. Transglutaminase 4 immunostaining was performed on a tissue microarray. The expression of transglutaminase 4 was evaluated by a scoring method based on the intensity and extent of staining. The clinical and pathological information was obtained through a review of medical records. Follow-up data were obtained by consulting the hospital medical records and the prostate cancer database of our department and by contacting patients or family members. We then compared the transglutaminase 4 expression levels between the prostate cancer tissues and the paracarcinoma tissues and evaluated the correlation of transglutaminase 4 expression with the clinical parameters and biochemical recurrence of prostate cancer. Our results indicated that the transglutaminase 4 staining was significantly higher in tumour tissue than in paracarcinoma tissue （P^O.O01） and was positively associated with higher Gleason score （P^O.O01） and higher prostate-specific antigen level （P=0.005）. Patients with transglutaminase 4 overexpression experienced shorter biochemical recurrence-free survival after surgery （P=0.042） in the univariate analysis but not in the multivariate analysis （P=0. 139）, which indicated that transglutaminase 4 may serve as a potential predictor of biochemical recurrence of prostate cancer.

Variability of anti-human transglutaminase testing in celiac disease across Mediterranean countries

To verify the precision and accuracy of transglutaminase antibodies (TGA) assays across Mediterranean countries. METHODSThis study involved 8 referral centres for celiac disease (CD) in 7 Mediterranean countries. A central laboratory prepared 8 kits of 7 blinded and randomized serum samples, with a titrated amount of Human TGA IgA. Each sample was analysed three times on three different days, with each centre running a total of 21 tests. The results were included in a blindly coded report form, which was sent to the coordinator centre. The coordinator estimated the mean coefficient of Variation (CoVar = σ/μ), the mean accuracy (Accur = Vobserved - Vreal) and the mean percent variation (Var% = [(Vobserved - Vreal)/Vreal] × 100). RESULTSThe analysis showed that 79.17% of the mean variation fell between -25% and +25% of the expected value, with the accuracy and precision progressively increasing with higher titres of TGA. From values 1.25 times greater than the normal cut-off, the measurements were highly reliable. CONCLUSIONTGA estimation is a crucial step for the diagnosis of CD; given its accuracy and precision, clinicians could be confident in establishing a diagnosis.

Comparison of Tissue Transglutaminase Activity During Young Panicle Development in Honglian-type Cytoplasmic Male Sterile Rice

To investigate the changes of tissue transglutaminase activity, the leaves and young panicles of rice at different developmental stages were excised from the Honglian-type cytoplasmic male sterile line, Yuetai A and its maintainer line, Yuetai B, respectively. An ELISA measurement protocol for tissue transglutaminase activity detection in rice was well established. The results indicated that the tissue transglutaminase activity was regulated positively by calcium cation, and the tissue transglutaminase activity in senescent leaves was remarkably higher than that in young leaves. No distinct difference was noted between Yuetai A and Yuetai B. Moreover, from the tetrad to binucleate stages the tissue transglutaminase activity increased gradually with the progression of the young panicle development and up to maximum at binucleate stage in Yuetai A. However, no similar changes were observed in Yuetai B. This indicates that the tissue transglutaminase is involved in cell programmed death in abortive pollen.

Expression of Tissue Transglutaminase in Cultured Bovine Trabecluar Meshwork Cells

Summary: To study whether cultured bovine trabecluar meshwork cells (BTMC) are capable of expressing tTG in protein and at mRNA level, BTMC were cultured in vitro and passaged three times, then the cells were transferred onto or cultured on sterile cover or submitted to isolation of RNA with Trizol, and the expression of tTG was detected by immunohistochemical technique and reverse transcription polymerase chain reaction (RT-PCR) respectively. Our results showed that tTG immunostaining was positive in the cytoplasm and rarely in the nucleus of cultured BTMC. No immunostaining was seen in the negative control. Moreover, a single RT-PCR amplified product whose sequence and size were in accordance with our known parameters was obtained. The expression of tTG in cultured BTMC was confirmed in protein and at mRNA level. BMTC is available more readily for the investigation of the relationship between tTG and primary open-angle glaucoma.

TGase介导玉米醇溶蛋白改善大豆分离蛋白膜性能的研究

为改善大豆分离蛋白膜的性能,利用碱性蛋白酶制备玉米醇溶蛋白酶解产物(ZH),通过转谷氨酰胺酶(TGase)催化大豆分离蛋白(SPI)与ZH发生交联反应,对反应条件进行了优化;通过控制反应时间得到4种修饰产物(分别为0 h-SPI/ZH、0.5 h-SPI/ZH、1 h-SPI/ZH、1.5 h-SPI/ZH),并对修饰产物制备的膜性能进行研究。结果表明:最佳的TGase催化SPI与ZH交联反应条件为SPI与ZH质量比3.5∶1、底物质量浓度40 mg/mL、pH 7.5、酶添加量10 U/g(以蛋白质质量计)、反应温度45℃、反应时间1.5 h;随着反应时间的延长,4种修饰产物制备的复合膜抗拉强度和不透明度增加,含水量、断裂伸长率和水蒸气透过率降低;与SPI膜相比,1.5 h-SPI/ZH制备的复合膜的抗拉强度增加了5.5%,含水量与水蒸气透过率分别下降了25.6%和32.2%,不透明度增加了114.2%。综上,采用TGase催化SPI与ZH发生交联,所制的复合膜综合品质较好,为SPI复合膜的开发提供了技术支持。

A peptide of 17 aminoacids from the N-terminal region of maize plastidial transglutaminase is essential for chloroplast targeting

Transglutaminases (TGases, EC 2.3.2.13) catalyse posttranslational modification of proteins by establishing ε-(γ-glutamyl) links and covalent conjugation of polyamines. In plants, the functionality of these enzymes is scarcely known. The maize transglutaminase gene (tgz), the only cloned plant TGase, produces major alterations in thylakoid membrane architecture when the transglutaminase (chlTGZ) protein was over-expressed in tobacco chloroplasts, significantly increasing the number of grana stacked layers. Here we demonstrate that nuclear transformation of rice plants starting from a tgz gene truncated in 17 N-terminal aas (tgzt) non altered chloroplast thylakoid structures. F3 transformed plants were analysed for TGase activity, chlTGZ presence and tgzt transcription levels. Transformed plants exhibited double the in vitro TGase activity of the non-transformed plants. Immunoblot and quantitative RT-PCR analysis results of tgzt-rice plants grown under different illumination periods revealed that chlTGZ maintains its differential expression depending on the light regime. Nevertheless, the maize protein was localised by confocal microscopy in the cell wall of transformed rice cells. TEM analyses of the transformed cells showed normal, non-altered chloroplast thylakoid structures with the maize protein preferentially located in the cell walls. The results confirmed that the tgz eliminated sequence is essential for chloroplast targeting, being its absence sufficient to the lack of protein expression in its original plastidal compartment. Interestingly, the immunolocalization of a putative endogenous rice TGase protein is also showed. These data give further information on plant TGase functionality and its relationship to photosynthetic membranes.

Correlation analysis of celiac sprue tissue transglutaminase and deamidated gliadin IgG/IgA

AIM:To indirectly determine if tissue transglutaminase(tTG)-specific T cells play a crucial role in the propagation of celiac disease.METHODS:Anti-deamidated gliadin peptide(DGP) and anti-tTG IgA and IgG were measured in the sera of celiac patients(both untreated and treated).The correlations were determined by Spearman's rank correlation test.RESULTS:In celiac patients,we found a very significant correlation between the production of DGP IgA and IgG(r = 0.75),indicating a simultaneous and ongoing production of these two isotypes reminiscent of oral vaccination studies.However,there was far less association between the production of tTG IgA and tTG IgG in celiac patients(r = 0.52).While tTG IgA was significantly correlated with DGP IgA(r = 0.80) and DGP IgG(r = 0.67),there was a weak correlation between production of anti-tTG IgG and the production of anti-DGP IgA(r = 0.38) and anti-DGP IgG(r = 0.43).CONCLUSION:These data demonstrate that the production of anti-tTG IgA is directly correlated to the production of anti-DGP IgG and IgA,whereas anti-tTG IgG is only weakly correlated.This result therefore supports the hapten-carrier theory that in well-established celiac patients anti-tTG IgA is produced by a set of B cells that are reacting against the complex of tTG-DGP in the absence of a tTG-specific T cell.

Baicalein and Salvia officinalis Extract Upregulate Transglutaminase 1 mRNA Expression via the Activation of Transient Receptor Potential Channel V4

Background: It is important to maintain skin homeostasis for cosmetic and medical reasons. Many ceramide-related ingredients and cosmetics have been developed to improve the skin barrier function and skin hydration. Similar to extracellular lipids, the cornified envelope, which is a structure formed beneath the plasma membrane, contributes to the skin barrier function as a scaffold for extracellular lipids. Therefore, in this study, we focused on transglutaminase 1 (TGM1) which is the key enzyme for formation of the cornified envelope Objective: The objectives of this study were to identify compounds that could upregulate the expression of TGM1 and evaluate their underlying action mechanisms. Methods: Expression of the transient receptor potential channel vanilloid subfamily member 4 (TRPV4) at the mRNA and protein levels was estimated by PCR and western blotting. Effects of baicalein and Salvia officinalis (SO) extract on TGM1 mRNA expression were measured by PCR. The involvement of TRPV4 in TGM1 mRNA expression was evaluated by the inhibition and silencing of TRPV4. Results: TRPV4 was expressed in both basal cell-like HaCaT cells and suprabasal cell-like HaCaT cells. Baicalein and SO extract upregulated TGM1 mRNA expression in basal cell-like HaCaT cells. However, inhibition and silencing of TRPV4 abrogated the effects of baicalein and SO extract. Conclusion: Baicalein and SO extract upregulated the expression of TGM1 mRNA via the activation of TRPV4, suggesting that it may improve the skin barrier function by enhancing cornified envelope formation.

2型转谷氨酰胺酶对人胶质母细胞瘤细胞U251放射敏感性的影响

为探讨2型转谷氨酰胺酶(transglutaminase 2,TG2)对胶质母细胞瘤(glioblastoma,GBM)放射敏感性的影响。通过生信分析TG2表达与胶质瘤病人预后的关系,并分析了其在GBM放射抵抗细胞株U251中的水平;瞬时转染得到TG2过表达细胞(U251-TG2)或空载细胞(U251-EV);CCK8法绘制生长曲线;transwell检测细胞迁移能力;不同剂量X射线照射后,检测细胞克隆形成能力、ROS水平;并通过免疫荧光检测γ-H2AX水平;Western blot检测自噬关键分子Beclin-1、LC3及mTOR磷酸化水平。结果显示,TG2高表达胶质瘤患者具有更差的无进展间隔期及总生存期,TG2在放射抵抗型U251中的表达显著高于野生型U251;U251-TG2细胞增殖能力高于U251-EV,且前者迁移能力高于后者;经X射线照射后,U251-TG2细胞克隆形成率高于U251-EV,前者ROS水平及γ-H2AX荧光焦点数均低于后者;自噬关键蛋白Beclin-1及自噬活性指标LC3-Ⅱ/Ⅰ比值在U251-TG2的水平均高于U251-EV,且前者mTOR磷酸化水平低于后者。实验结果证明,X射线照射后,TG2可能通过抑制mTOR磷酸化的方式促进自噬,进而降低GBM细胞U251的放射敏感性。