Research progress of metformin in the pathogenesis of pulmonary fibrosis / 中国临床药理学与治疗学

Pulmonary fibrosis is a chronic, progressive and irreversible respiratory disease characterized by hyperposition of extracellular matrix leading to inflammation and extensive lung remodeling. There is currently no effective treatment. Multiple studies have shown that metformin is a classic antiglycemic drug with antifibrotic potential. However, at present, there is no consensus on the specific mechanism of metformin's anti-fibrosis effect, and this paper reviews the research progress of metformin in the field of pulmonary fibrosis in recent years, mainly from IGF-1/IGF-1R/PI3K signaling, AMPK/mTOR signaling, TGF-β/Smad signaling pathway, and intervening in myofibroblast proliferation and apoptosis, improving oxidative stress, inhibiting epithelial interstitial transformation and transglutaminase. In order to be able to more deeply and comprehensively understand the antifibrosis mechanism and clinical application scope of metformin in the future, and provide new ideas for the treatment of pulmonary fibrosis.

Evaluation of nuclear NF-κB, transglutaminase2, and ERCC1 as predictors of platinum resistance in testicular tumors

ABSTRACT Purpose: Testicular germ cells tumor (TGCT) are associated with a high cure rate and are treated with platinum-based chemotherapy. However, a group of testicular cancer patients may have a very unfavorable evolution and insensitivity to the main therapeutic agent chemotherapy (CT) cisplatin. The aim of this study was to evaluate the risk of recurrence and overall survival related to the expression of nuclear factor kappa-B (NF-κB), transglutaminase 2 (TG2) and excision repair cross-complementation group 1 (ERCC1) in patients with TGCT treated with platinum combinations. Patients and Methods: A retrospective study was performed with TGCT patients treated with platinum-based chemotherapy. Immunohistochemical analysis was performed and the expression was correlated with clinical and laboratory data. Results: Fifty patients were included, the mean age was 28.4 years (18 to 45), and 76% were non-seminoma. All patients were treated with standard cisplatin, etoposide and bleomycin or cisplatin, and etoposide. Patient's analyzed immunodetection for NF-κB, TG2, and ERCC1 were positive in 76%, 54% and 42%, respectively. Multivariate analysis identified that positive expressions to ERCC1 and NF-κB are independent risk factors for higher recurrence TGCT after chemotherapy (RR 2.96 and 3.16, respectively). Patients with positive expression of ERCC1 presented a poor overall survival rate for 10-year follow (p=0.001). Conclusions: The expression of ERCC1 and NF-κB give a worse prognosis for relapse, and only ERCC1 had an influence on the overall survival of TGCT patients treated with platinum-based chemotherapy. These may represent markers that predict poor clinical outcome and response to cisplatin.

Transglutaminase 2 Promotes Autophagy by LC3 Induction through p53 Depletion in Cancer Cell

Transglutaminase 2 (TGase 2) plays a key role in p53 regulation, depleting p53 tumor suppressor through autophagy in renal cell carcinoma. We found that microtubule-associated protein 1A/1B-light chain 3 (LC3), a hallmark of autophagy, were tightly associated with the level of TGase 2 in cancer cells. TGase 2 overexpression increased LC3 levels, and TGase 2 knockdown decreased LC3 levels in cancer cells. Transcript abundance of LC3 was inversely correlated with level of wild type p53. TGase 2 knockdown using siRNA, or TGase 2 inhibition using GK921 significantly reduced autophagy through reduction of LC3 transcription, which was followed by restoration of p53 levels in cancer cells. TGase 2 overexpression promoted the autophagy process by LC3 induction, which was correlated with p53 depletion in cancer cells. Rapamycin-resistant cancer cells also showed higher expression of LC3 compared to the rapamycin-sensitive cancer cells, which was tightly correlated with TGase 2 levels. TGase 2 knockdown or TGase 2 inhibition sensitized rapamycin-resistant cancer cells to drug treatment. In summary, TGase 2 induces drug resistance by potentiating autophagy through LC3 induction via p53 regulation in cancer.

Urinary transglutaminase 2 as a potent biomarker to predict interstitial fibrosis and tubular atrophy of kidney allograft during early posttransplant period in deceased donor kidney transplantation

PURPOSE: Transglutaminase type 2 (TG2) is an extracellular matrix crosslinking enzyme with a pivotal role in kidney fibrosis. We tested whether quantification of urinary TG2 may represent a noninvasive method to estimate the severity of kidney allograft fibrosis. METHODS: We prospectively collected urine specimens from 18 deceased donor kidney transplant recipients at 1-day, 7-day, 1-month, 3-month, and 6-month posttransplant. In addition, kidney allograft tissue specimens at 0-day and 6-month posttransplant were sampled to analyze the correlation of urinary TG2 and kidney allograft fibrosis. RESULTS: Thirteen recipients had increased interstitial fibrosis and tubular atrophy (IFTA) scores at the 6-month protocol biopsy (IFTA group). The mean level of urinary TG2 in the IFTA group was higher compared to that of 5 other recipients without IFTA (no IFTA group). Conversely, the mean level of urinary syndecan-4 in the IFTA group was lower than levels in patients without IFTA. In the IFTA group, double immunofluorescent staining revealed that TG2 intensity was significantly upregulated and colocalizations of TG2/heparin sulfate proteoglycan and nuclear syndecan-4 were prominent, usually around tubular structures. CONCLUSION: Urinary TG2 in early posttransplant periods is a potent biomarker for kidney allograft inflammation or fibrosis.

A participação da autofagia na regulação da célula-tronco hemopoética em camundongos knockouts para Atg7 e transglutaminase 2 / The participation of autophagy in hemopoietic stem cell regulation in mice Knockouts for Atg7 and transglutaminase 2

A desnutrição é um dos principais problemas de saúde pública do mundo, que contribui significativamente para o aumento da morbidade e mortalidade. Estima-se um total de 815 milhões de pessoas subnutridas no mundo, e apesar da melhoria dos recursos alimentares o número de pessoas desnutridas ainda é alarmante. Estudos de nosso laboratório tem demonstrado, em modelo murino de desnutrição proteica, hipoplasia medular com evidências histológicas de alterações na matriz extracelular (MEC) e permanência da célula-tronco hemopoética (CTH) na fase G0/G1 do ciclo celular em camundongos desnutridos. Dados deste trabalho evidenciaram alterações nas proteínas Akt /mTOR, que podem contribuir para o aumento da expressão autofágica nas CTHs e CTPHs (célula-tronco progenitora). A literatura demonstra que desequilíbrios nutricionais e metabólicos podem induzir ativação autofágica. Autofagia é um processo catabólico que participa da manutenção da homeostase celular, da MEC e na regulação das CTHs, dados deste trabalho demonstram diminuição da quantidade de CTH e CTPH em camundongos desnutridos sem a presença do gene Atg7, proteína participativa no processo autofágico. Já camundongos com deleção da transglutaminase 2 (TG2) e submetidos a privação de nutrientes por 24 horas , apresentou diminuição da quantidade de CTH e aumento da diferenciação da CTPH. A TG2 tem participação na impulsão e formação do fagóforo (processo inicial autofágico). Considerando que a desnutrição proteica leva a comprometimento da hemopoese, alterações no ciclo celular das CTHs e hipoplasia medular com pancitopenia periférica e que privação e ou jejum prolongado de nutrientes pode aumentar a atividade autofágica, concluímos nesse projeto que autofagia é importante para regulação da CTH e diferenciação da CTPH, entretanto a desnutrição proteica e privação de nutrientes estimula de maneira diversa o mecanismo de diferenciação da CTH

Malnutrition is one of the world's major public health problems, which contributes significantly to increased morbidity and mortality. An estimated 815 million people are undernourished in the world, and despite the improvement in food resources the number of undernourished people is still alarming. Studies of our laboratory have demonstrated in murine model of protein malnutrition, medullary hypoplasia with histological evidence of extracellular matrix (ECM) changes and hemopoietic stem cell (HSC) stay in the G0/ G1 phase of the cell cycle in malnourished mice. Data from this work showed alterations in Akt / mTOR proteins, which may contribute to the increase of autophagic expression in HSC and HPC (progenitor stem cell). The literature demonstrates that nutritional and metabolic imbalances can induce autophagic activation. Autophagy is a catabolic process that participates in the maintenance of cellular homeostasis, ECM and in the regulation of HSC, data from this work demonstrate a decrease in the amount of HSC and HPC in malnourished mice without the presence of the Atg7 gene, a participatory protein in the autophagic process. Mice with transglutaminase 2 deletion (TG2) and submitted to nutrient deprivation for 24 hours showed a decrease in the amount of HSC and an increase in the differentiation of HPC. TG2 plays a role in the uptake and formation of phagophore (autophagic initial process). Considering that protein malnutrition leads to hemopoiesis, alterations in the cell cycle of HSC and spinal cord hypoplasia with peripheral pancytopenia, and that prolonged nutrient starvation or fasting may increase the autophagic activity, we conclude in this project that autophagy is important for regulation of HSC and differentiation of HPC, however, protein malnutrition and nutrient deprivation stimulate in a different way the mechanism of differentiation of HSC

Regulation of Inflammatory Response in Periodontal Ligament Cells by Transglutaminase 2

Transglutaminase2 (TGM2) is a multi-functional calcium dependent enzyme that affects angiogenesis, apoptosis, differentiation, attachment, and changes in the extracellular matrix. However, its function in periodontal tissue has not yet been studied. The aim of this study was to investigate the association of the TGM2 expression and the modulation of inflammatory mediators in inflamed periodontal ligament (PDL) cells induced by pro-inflammatory cytokines such as Interleukin-1β and the Tumor necrosis factor-α. The expression of TGM2 was increased in the inflamed periodontal tissue and PDL cells. Over-expressed TGM2 in the PDL cells increased expression of MMP1, MMP3, IL-6, CXCL8, and PTGS2. Conversely, inhibition of TGM2 activity using LDN27219, a TGM2 inhibitor, resulted in decreased expression of MMP1, MMP3, IL-6, and CXCL8. The mRNA expression was confirmed by RT-PCR and quantified by qRT-PCR. Protein levels were also confirmed by immunofluoroscence staining. These results suggest that TGM2 plays an important role in the regulation of inflammatory mediators which exacerbate tissue damage in inflamed periodontal tissue.

Expression analysis of transglutaminase 2 in premalignant lesions of the cervix

Background: The medical management of low-grade squamous intraepithelial lesions (LSIL) is variable, thus a biomarker could assist with the clinical conduct. Type 2 transglutaminase (TG2) has been proposed as a cellular-interfering factor in HPV infection and carcinogenesis. Therefore, this study has the objective of evaluating TG2 expression in LSIL and highgrade squamous intraepithelial lesions (HSIL) and of relating it to the different HPV viral types. Methods: This study included 146 patients with suspected LSIL or HSIL detected in routine conventional Papanicolaou tests. The presence of HPV DNA and viral typing was defined by the polymerase chain reaction method (PCR). TG2 Immunohistochemistry (IHC) was conducted according to the manufacturer's instructions; IHC was carried out in an Autosteiner-Link 48 Dako equipment. IHC quantitation was performed by relative expression and by using the software Image J. Qualitative variables, such as frequencies and proportions, were compared by using the χ2 test for independent samples. For comparison of the qualitative to the quantitative data, nonparametric Mann-Whitney test was used. Results: The association between histopathological examination and TG2 was statistically significant (p <0.05). Results showed that patients with normal cervical histopathology and LSIL are locally associated with TG2 expression levels >50% (p <0.05), and patients with HSIL are associated with no TG2 expression (p <0.05). The analysis of the samples with the Image J software shows a significant (p <0,001) decrease in TG2 immunostaining in HSIL if compared to normal and to LSIL samples. This demonstrates a correlation between the relative quantification and the results provided by Image J. Analysis of HPV types showed a significant association with HPV11 (p = 0.031). This indicates that patients with HPV type 11 had higher TG2 values than patients with different types. Image J analysis showed no significant association between TG2 and HPV viral types. Conclusion: The present data suggest that TG 2 has a high expression in LSIL and normal tissues, and decreased in HSIL. We also observed that its expression is associated with HPV11 (AU)

Búsqueda activa de enfermedad celíaca en familiares de primer grado de casos celíacos / Active search of celiac disease among first degree relatives of known celiac patients

Background: Active search of celiac disease (CD) among risk groups has significantly increased the scope of known clinical variants. Aim: To measure the frequency and clinical characteristics of CD among first degree relatives (FDR) of known celiac cases. Material and Methods: Between January 2012-August 2013, 37 patients with celiac disease brought 113 FDR for assessment. Their clinical data was recorded and a blood sample was obtained to measure serum Immunoglobulin A (IgA) levels, anti-transglutaminase (tTG) and anti-endomisial (EMA) antibodies. Cases with positive serology were advised to have an intestinal biopsy. Results: Fourteen relatives (12.4%) had positive serological results and none had IgA deficiency. Among IgA-tTG (-) cases, measurement of IgA/IgG-tTG identified an additional case. Two of the 14 relatives were EMA positive. All 14 cases were advised to have an intestinal biopsy, but only 6 accepted the procedure. In two, the intestinal lesion was classified Marsh ≥ 2 and active CD was diagnosed. Histology in the remaining four was Marsh 0/1 and were diagnosed potential CD, remaining under control, without gluten free diet. Conclusions: Serological prevalence of CD among first degree relatives of known celiac cases was 15 fold greater than in THE general Chilean population, strongly supporting the idea of implementing active search to customary clinical practice. Determination of IgA/IgG-tTG may be useful to improve the yield of active search. Intestinal biopsies were crucial to differentiate active classic CD from potential CD.

The Role of Transglutaminase 2 (TG2) in Definition of Cancer Hallmarks.

Over the past three decades, TGM2, a stress-responsive gene encoding transglutaminase 2 (TG2) has been identified as one of the several genes that may be involved in carcinogenesis and cancer physiology. TG2 is a pleiotropic calcium-dependent enzyme belonging to the transglutaminase family of enzymes, which post-translationally modify glutaminyl and lysyl side chains on the surface of both in vivo and in vitro substrate proteins. Unlike other members of the transglutaminase family, TG2 has additional Ca2+-independent enzymatic and non-enzymatic activities, which have been directly or indirectly implicated in diverse cellular physiological events, including cell growth and differentiation, cell adhesion and morphology, extracellular matrix stabilization, wound healing, cellular development, receptor-mediated endocytosis, apoptosis, and disease pathology. TG2 has specialized biochemical, structural and functional elements, wide tissue distribution and subcellular localisation, as well as broad substrate specificity. These specialised features of TG2 account for its multiple patho-physiological functionalities. Considering the multiplicity of TG2 functions and its importance in disease pathology, including cancer; we have reviewed herein, the importance of TG2 in the definition of the hallmark capabilities of cancer cells. This was done with the view to deepen our understanding of the role of TG2 in carcinogenesis and recapitulating its potential as a therapeutic target for cancer treatment.

History and Biology of Transglutaminase 2: A Synopsis.

Transglutaminase 2 (TG2) belongs to the family of transglutaminase, a large group of intracellular and extracellular enzymes that primarily catalyze the Ca2+-dependent posttranslational modification of proteins. Discovery of the first transglutaminase in the early 1920s, has subsequently lead to the identification of nine members of the enzyme family including TG2; the most abundant, most popular and most studied member of the transglutaminase enzyme family. The popularity of TG2 is due to its uniqueness amongst other members of the Transglutaminase (Tgase) family. Its difference from other Tgase family members is due to its specialized structural and biochemical activities; abundant tissue distribution and sub-cellular localization; and multi-functionality and physiology. The growing interests in TG2 and related research has resulted to an attendant mega-research output; and the need to produce a well-structured compilation of data on this popular enzyme has arisen. It is against this background, that we have compiled herein, a synopsis of available literature on TG2 history, structural and biochemical activities, tissue distribution, and physiology. This was done with the view to providing a compendium of background information that could be handy to researchers and new interest in the field of TG2 research.

Effects of Transglutaminase 2 Inhibition on Ventilator-Induced Lung Injury

This study was performed to examine the role of transglutaminase 2 (TG2) in ventilator-induced lung injury (VILI). C57BL/6 mice were divided into six experimental groups: 1) control group; 2) lipopolysaccharide (LPS) group; 3) lung protective ventilation (LPV) group; 4) VILI group; 5) VILI with cystamine, a TG2 inhibitor, pretreatment (Cyst+VILI) group; and 6) LPV with cystamine pretreatment (Cyst+LPV) group. Acute lung injury (ALI) score, TG2 activity and gene expression, inflammatory cytokines, and nuclear factor-kappaB (NF-kappaB) activity were measured. TG2 activity and gene expression were significantly increased in the VILI group (P < 0.05). Cystamine pretreatment significantly decreased TG2 activity and gene expression in the Cyst+VILI group (P < 0.05). Inflammatory cytokines were higher in the VILI group than in the LPS and LPV groups (P < 0.05), and significantly lower in the Cyst+VILI group than the VILI group (P < 0.05). NF-kappaB activity was increased in the VILI group compared with the LPS and LPV groups (P < 0.05), and significantly decreased in the Cyst+VILI group compared to the VILI group (P = 0.029). The ALI score of the Cyst+VILI group was lower than the VILI group, but the difference was not statistically significant (P = 0.105). These results suggest potential roles of TG2 in the pathogenesis of VILI.

Involvement of Transglutaminase-2 in alpha-MSH-Induced Melanogenesis in SK-MEL-2 Human Melanoma Cells

Skin hyperpigmentation is one of the most common skin disorders caused by abnormal melanogenesis. The mechanism and key factors at play are not fully understood. Previous reports have indicated that cystamine (CTM) inhibits melanin synthesis, though its molecular mechanism in melanogenesis remains unclear. In the present study, we investigated the effect of CTM on melanin production using ELISA reader and the expression of proteins involved in melanogenesis by Western blotting, and examined the involvement of transglutaminase-2 (Tgase-2) in SK-MEL-2 human melanoma cells by gene silencing. In the results, CTM dose-dependently suppressed melanin production and dendrite extension in alpha-MSH-induced melanogenesis of SK-MEL-2 human melanoma cells. CTM also suppressed alpha-MSH-induced chemotactic migration as well as the expressions of melanogenesis factors TRP-1, TRP-2 and MITF in alpha-MSH-treated SK-MEL-2 cells. Meanwhile, gene silencing of Tgase-2 suppressed dendrite extension and the expressions of TRP-1 and TRP-2 in alpha-MSH-treated SK-MEL-2 cells. Overall, these findings suggested that CTM suppresses alpha-MSH-induced melanogenesis via Tgase-2 inhibition and that therefore, Tgase-2 might be a new target in hyperpigmentation disorder therapy.

12-O-Tetradecanoylphorbol-13-Acetate Induces Keratin 8 Phosphorylation and Reorganization via Expression of Transglutaminase-2

The stiffness of cancer cells is attributable to intermediate filaments such as keratin. Perinuclear reorganization via phosphorylation of specific serine residue in keratin is implicated in the deformability of metastatic cancer cells including the human pancreatic carcinoma cell line (PANC-1). 12-O-Tetradecanoylphorbol-13-acetate (TPA) is a potent tumor promoter and protein kinase C (PKC) activator. However, its effects on phosphorylation and reorganization of keratin 8 (K8) are not well known. Therefore, we examined the underlying mechanism and effect of TPA on K8 phosphorylation and reorganization. TPA induced phosphorylation and reorganization of K8 and transglutaminase-2 (Tgase-2) expression in a time- and dose-dependent manner in PANC-1 cells. These effects peaked after 45 min and 100 nM of TPA treatment. We next investigated, using cystamine (CTM), Tgase inhibitor, and Tgase-2 gene silencing, Tgase-2's possible involvement in TPA-induced K8 phosphorylation and reorganization. We found that Tgase-2 gene silencing inhibited K8 phosphorylation and reorganization in PANC-1 cells. Tgase-2 gene silencing, we additionally discovered, suppressed TPA-induced migration of PANC-1 cells and Tgase-2 overexpression induced migration of PANC-1 cells. Overall, these results suggested that TPA induced K8 phosphorylation and reorganization via Tgase-2 expression in PANC-1 cells.

The Pathologic Characteristics of Pingueculae on Autofluorescence Images

PURPOSE: To analyze the autofluorescence (AF) properties of pinguecula using cobalt-blue and yellow filters and to investigate the nature and pathogenesis of pingueculae using histochemical and immunohistochemical staining. METHODS: Fifty pingueculae in 40 patients were included in this study. AF of the pingueculae was observed and analyzed using a cobalt-blue filter with an additional yellow filter on a slit-lamp. Hematoxylin-eosin and immunohistochemical stainings were performed on surgical specimens of pingueculae that were prepared from each patient. Immunohistochemical staining included Congo red, Oil Red O, periodic acid-Schiff (PAS), Masson's trichrome, transglutaminase-2 (TG-2), mesenchymal stem cell markers CD29 (beta-1-integrin), and CD34. RESULTS: AF images revealed hyper-AF in the pinguecula area. The AF lesions of pingueculae showed superficial punctuate erosions and avascular lesions. Deposition of eosinophilic and amorphous materials in the subepithelial layer of the pinguecula were observed on hematoxylin-eosin staining. Historeactivities to Congo red, PAS, Oil Red O, alcian blue, and Masson's trichrome were not detected, but immunoreactivities to CD29, CD34, and TG-2 were detected in the pingueculae with AF. However, CD29, CD34, and TG-2 were not detected in the pingueculae without AF. CONCLUSIONS: The AF of pingueculae may be related to CD29, CD34, and TG-2. We suggest that pingueculae with AF have a different pathogenesis compared to pingueculae without AF.

Transglutaminase-2 Is Involved in Expression of Osteoprotegerin in MG-63 Osteosarcoma Cells

Osteoprotegerin (OPG) is a secreted glycoprotein and a member of the tumor necrosis factor receptor superfamily. It usually functions in bone remodeling, by inhibiting osteoclastogenesis through interaction with a receptor activator of the nuclear factor kappaB (RANKL). Transglutaminases-2 (Tgase-2) is a group of multifunctional enzymes that plays a role in cancer cell metastasis and bone formation. However, relationship between OPG and Tgase-2 is not studied. Therefore, we investigated the involvement of 12-O-Tetradecanoylphorbol 13-acetate in the expression of OPG in MG-63 osteosarcoma cells. Interleukin-1beta time-dependently induced OPG and Tgase-2 expression in cell lysates and media of the MG-63 cells by a Western blot. Additional 110 kda band was found in the media of MG-63 cells. 12-O-Tetradecanoylphorbol 13-acetate also induced OPG and Tgase-2 expression. However, an 110 kda band was not found in TPA-treated media of MG-63 cells. Cystamine, a Tgase-2 inhibitor, dose-dependently suppressed the expression of OPG in MG-63 cells. Gene silencing of Tgase-2 also significantly suppressed the expression of OPG in MG-63 cells. Next, we examined whether a band of 110 kda of OPG contains an isopeptide bond, an indication of Tgase-2 action, by monoclonal antibody specific for the isopeptide bond. However, we could not find the isopeptide bond at 110 kda but 77 kda, which is believed to be the band position of Tgase-2. This suggested that 110 kda is not the direct product of Tgase-2's action. All together, OPG and Tgase-2 is induced by IL-1beta or TPA in MG-63 cells and Tgase-2 is involved in OPG expression in MG-63 cells.

Transglutaminase 2 Expression Predicts Progression Free Survival in Non-Small Cell Lung Cancer Patients Treated with Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor

Transglutaminase 2 (TG2), a cross-linking enzyme, is involved in drug resistance and in the constitutive activation of nuclear factor kappa B (NF-kappaB). We investigated the association of non-small cell lung cancer (NSCLC) treatment efficacy with TG2 and NF-kappaB expression in 120 patients: 102 with adenocarcinoma and 18 with other histologic types. All patients underwent surgery; 88 received adjuvant chemotherapy, with 28 receiving platinum-based doublet chemotherapy as first-line treatment and 29 receiving epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) therapy. Patients' TG2 and NF-kappaB expression values were calculated semiquantitatively. The median TG2 value was 50 (range, 0-300) and the median NF-kappaB value was 20 (range, 0-240). Disease-free survival did not differ between the low- and high-TG2 groups. Among patients who received palliative platinum-based doublet chemotherapy, progression free survival (PFS) was longer in the low-TG2 group than in the high-TG2 group (11.0 vs. 7.0 months; P=0.330). Among those who received EGFR-TKI therapy, PFS was also longer in the low-TG2 group than in the high-TG 2 group (11.0 vs. 2.0 months; P=0.013). Similarly, in EGFR wild-type patients treated with EGFR-TKI, PFS was longer in patients with low TG2 expression (9.0 vs. 2.0 months; P=0.013). TG2 expression levels can predict PFS in patients with NSCLC treated with EGFR-TKI.

Ethacrynic Acid Inhibits Sphingosylphosphorylcholine-Induced Keratin 8 Phosphorylation and Reorganization via Transglutaminase-2 Inhibition

Sphingosylphosphorylcholine (SPC) is significantly increased in the malicious ascites of tumor patients and induces perinuclear reorganization of keratin 8 (K8) filaments in PANC-1 cells. The reorganization contributes to the viscoelasticity of metastatic cancer cells resulting in increased migration. Recently, we reported that transglutaminase-2 (Tgase-2) is involved in SPC-induced K8 phosphorylation and reorganization. However, effects of Tgase-2 inhibitors on SPC-induced K8 phosphorylation and reorganization were not clearly studied. We found that ethacrynic acid (ECA) concentration-dependently inhibited Tgase-2. Therefore, we examined the effects of ECA on SPC-induced K8 phosphorylation and reorganization. ECA concentration-dependently suppressed the SPC-induced phosphorylation and perinuclear reorganization of K8. ECA also suppressed the SPC-induced migration and invasion. SPC induced JNK activation through Tgase-2 expression and ECA suppressed the activation and expression of JNK in PANC-1 cells. These results suggested that ECA might be useful to control Tgase-2 dependent metastasis of cancer cells such as pancreatic cancer and lung cancers.

Transglutaminase 2 inhibits apoptosis induced by calciumoverload through down-regulation of Bax

An abrupt increase of intracellular Ca2+ is observed in cells under hypoxic or oxidatively stressed conditions. The dysregulated increase of cytosolic Ca2+ triggers apoptotic cell death through mitochondrial swelling and activation of Ca2+-dependent enzymes. Transglutaminase 2 (TG2) is a Ca2+-dependent enzyme that catalyzes transamidation reaction producing cross-linked and polyaminated proteins. TG2 activity is known to be involved in the apoptotic process. However, the pro-apoptotic role of TG2 is still controversial. In this study, we investigate the role of TG2 in apoptosis induced by Ca2+-overload. Overexpression of TG2 inhibited the A23187-induced apoptosis through suppression of caspase-3 and -9 activities, cytochrome c release into cytosol, and mitochondria membrane depolarization. Conversely, down-regulation of TG2 caused the increases of cell death, caspase-3 activity and cytochrome c in cytosol in response to Ca2+-overload. Western blot analysis of Bcl-2 family proteins showed that TG2 reduced the expression level of Bax protein. Moreover, overexpression of Bax abrogated the anti-apoptotic effect of TG2, indicating that TG2-mediated suppression of Bax is responsible for inhibiting cell death under Ca2+-overloaded conditions. Our findings revealed a novel anti-apoptotic pathway involving TG2, and suggested the induction of TG2 as a novel strategy for promoting cell survival in diseases such as ischemia and neurodegeneration.

Differential gene expression of transglutaminase 2 in term pregnancy with and without labor / 대한산부인과학회지

OBJECTIVE: Our purpose was to investigate transglutaminase 2 (TGM2) mRNA and protein expressions in term placentas and fetal membranes delivered with labor compared to no labor. METHODS: Samples were obtained from five cases delivered with labor and five cases delivered without labor after 38 weeks of gestation. Each sample was collected from amnion, chorion, central and peripheral portion of the basal plate of placenta. Real time polymerase chain reaction (RT-PCR) was done to analyze mRNA expression of TGM2. Western blot was done and TGM2 protein level was detected. Mann-Whitney U test was used for statistic analysis. RESULTS: In labor group, TGM2 mRNA expressions were decreased compared to no labor group in 3 sampling sites except chorion (0.66+/-0.10 vs 1.29+/-0.12 in peripheral placenta, 0.67+/-0.23 vs 1.02+/-0.02 in central placenta, 0.70+/-0.16 vs 1.04+/-0.05 in amnion in contrast with 1.62+/-0.64 vs 1.56+/-0.21 in chorion). TGM2 protein expressions of four differential portions were decreased in all labor groups (1.05+/-0.35 vs 1.27+/-0.19 in peripheral placenta, 0.69+/-0.84 vs 0.84+/-0.31 in central placenta, 0.33+/-0.15 vs 0.39+/-0.33 in amnion, 0.96+/-0.18 vs 1.77+/-0.61 in chorion). CONCLUSIONS: This result suggests that TGM2 might involve in labor progress of term pregnancy.

Expression of Tissue Tissue-transglutaminase-2 (TGM2) and Cyclo-oxygenase (COX) in the Fetal Membrane of Preterm Birth / 대한주산의학회잡지

BACKGROUND: Preterm labor accounts for one third of preterm deliveries. However, the causes and the mechanism of preterm labor are still under investigation. The purpose of this study was to investigate the changes of tissue transglutaminase 2 (TGM2) and cyclo-oxigenase I,II in the fetal membrane of patients with preterm birth compared with patients with term delivery. METHODS: Fetal membrane were obtained from women with preterm birth due to preterm labor (n=3) and from the women with term delivery (n=3) after each vaginal birth. The expression of TGM2, COX I & II were assessed by RT-PCR and immunoblotting analysis of the amnion and chorion. Nonparametric statistics were used for analysis. RESULTS: In the amnion in patients with preterm delivery, the expression of TGM2, COX I and COX II mRNA were increased by 2.3-fold, 2.7-fold, 1.3-fold, respectively, compared to term delivery with labor. The protein expression of TGM2 and COX I in these patients was increased in 1.9-fold and 2.1-fold but COX II protein expression showed no significant change, compared to term delivery with labor. In the chorion in patients with preterm delivery, the expression of TGM2, COX I and COX II mRNA showed no significant change, compared to term delivery with labor, but the protein concentration was significantly increased in 14.6-fold, 1.4-fold and 1.3-fold respectively, compared to term delivery with labor. CONCLUSION: This study shows that TMG2 and COX I are expressed more in the fetal membrane at preterm delivery caused by preterm labor, compared to term delivery with labor. These data suggests that the mechanism of preterm labor might be different form term labor.