Genomic characterization of vulvar squamous cell carcinoma reveals differential gene expression based on clinical outcome.

OBJECTIVE: The greatest challenge in the management of vulvar squamous cell carcinoma (VSCC) is treatment of recurrent disease where options for surgery and radiation have been exhausted, or treatment of disease where distant metastasis is present. Identification of mutations differentially expressed between tumor from patients who died of aggressive disease and tumor from patients with an indolent course could reveal novel prognostic indicators and guide development of therapeutic drugs. METHODS: From 202 consecutive patients with VSCC, patients who recurred and died of disease (group A) were identified and matched by age, tumor size, depth of invasion and nodal status with those whose disease did not recur (group B). Tumors from 21 patients were subjected to whole exome sequencing of DNA and RNA, immunohistochemistry (IHC) antibodies of PD-L1 and P16, and in-situ hybridization (ISH) for high-risk HPV. RESULTS: Analysis of DNA and RNA revealed six genes that were strongly differentially expressed between group A and B: TGM3, ACVR2A, ROS1, NFEL2, CCND1 and BCL6. Clinically relevant DNA mutations were significantly greater in group A versus B: 7 vs 2.3 mutations per patient. The most common genomic alterations were mutations in TP53 and the promoter region of TERT. Other common genomic events include alterations of FAT1, CDKN2A, PIK3CA, CCND1, and LRP1B. All samples were MSI stable and tumor mutational burden (TMB) was similar in groups A and B. Most VSCC specimens (81%) were positive for PD-L1. CONCLUSIONS: ACVR2A and TGM3 are significantly under-expressed in tumors with poor outcome, suggesting they may play a role in tumor suppression. Clinical outcome of VSCC appears independent of MSI, TMB, or PD-L1 status.

Antibody Responses to Transglutaminase 3 in Dermatitis Herpetiformis: Lessons from Celiac Disease.

Dermatitis herpetiformis (DH) is the skin manifestation of celiac disease, presenting with a blistering rash typically on the knees, elbows, buttocks and scalp. In both DH and celiac disease, exposure to dietary gluten triggers a cascade of events resulting in the production of autoantibodies against the transglutaminase (TG) enzyme, mainly TG2 but often also TG3. The latter is considered to be the primary autoantigen in DH. The dynamics of the development of the TG2-targeted autoimmune response have been studied in depth in celiac disease, but the immunological process underlying DH pathophysiology is incompletely understood. Part of this process is the occurrence of granular deposits of IgA and TG3 in the perilesional skin. While this serves as the primary diagnostic finding in DH, the role of these immunocomplexes in the pathogenesis is unknown. Intriguingly, even though gluten-intolerance likely develops initially in a similar manner in both DH and celiac disease, after the onset of the disease, its manifestations differ widely.

Transglutaminase 3 Reduces the Severity of Psoriasis in Imiquimod-Treated Mouse Skin.

Four transglutaminase (TG) isoforms have been detected in epidermal keratinocytes: TG1, TG2, TG3, and TG5. Except for TG1 and TG3, their contribution to keratinocyte development and structure remains undefined. In this paper, we focused on the roles of TG2 and TG3 in imiquimod-induced psoriasis in mouse skin. We evaluated the severity of psoriasis markers in the skin of imiquimod-treated TG3 null and TG2 null mice. Our results showed that compromised TG3KO mouse skin was more responsive than WT or TG2KO mouse skin to the action of the pro-inflammatory drug imiquimod.

Separate Gut Plasma Cell Populations Produce Auto-Antibodies against Transglutaminase 2 and Transglutaminase 3 in Dermatitis Herpetiformis.

Dermatitis herpetiformis (DH) is an inflammatory skin disorder often considered as an extra intestinal manifestation of celiac disease (CeD). Hallmarks of CeD and DH are auto-antibodies to transglutaminase 2 (TG2) and transglutaminase 3 (TG3), respectively. DH patients have auto-antibodies reactive with both transglutaminase enzymes. Here it is reported that in DH both gut plasma cells and serum auto-antibodies are specific for either TG2 or TG3 with no TG2-TG3 cross reactivity. By generating monoclonal antibodies from TG3-specific duodenal plasma cells of DH patients, three conformational epitope groups are defined. Both TG2-specific and TG3-specific gut plasma cells have few immunoglobulin (Ig) mutations, and the two transglutaminase-reactive populations show distinct selection of certain heavy and light chain V-genes. Mass spectrometry analysis of TG3-specific serum IgA corroborates preferential usage of IGHV2-5 in combination with IGKV4-1. Collectively, these results demonstrate parallel induction of anti-TG2 and anti-TG3 auto-antibody responses involving separate B-cell populations in DH patients.

Transglutaminase 3 expression in hepatocellular carcinoma patients: Correlation with tumor features and survival profile.

BACKGROUND: Transglutaminase 3 (TGM3) regulates multiple oncogene pathways (GSK-3ß/ß-catenin pathway, Akt/ERK pathway, etc.) to promote hepatocellular carcinoma (HCC) cell proliferation, migration and invasion, however, its clinical value for HCC management is still limited. Therefore, we conducted this study to compare the TGM3 expression between tumor tissue and paired adjacent noncancerous tissue, aiming to explore the clinical application of TGM3 in HCC patients. METHODS: Totally, 208 HCC patients were enrolled and their clinicopathological features were collected. Then, 208 pairs of HCC specimens and adjacent noncancerous specimens were used to detect TGM3 protein expression by IHC assay and assessed by a semi-quantitative scoring method. Besides, 157 pairs were proposed to detect TGM3 mRNA expression by RT-qPCR. RESULTS: Both TGM3 protein (P<0.001) and mRNA (P<0.001) levels were increased in HCC specimens compared to adjacent noncancerous specimens. Besides, TGM3 high protein expression correlated with multifocal tumor nodules (P<0.001), advanced Barcelona Clinic Liver Cancer (BCLC) stage (P = 0.006), higher carcinoembryonic antigen (P = 0.038) and alpha-fetoprotein (AFP) (P<0.001). While TGM3 high mRNA expression correlated with multifocal tumor nodules (P = 0.025), largest tumor size ≥ 5.0 cm (P = 0.042) and higher AFP (P = 0.019). Furthermore, both TGM3 protein (P = 0.002) and mRNA (P = 0.028) high expressions correlated with shorter overall survival (OS). While after adjustment by multivariant Cox's regression, TGM3 protein high expression (vs. low) independently predicted worse OS (P = 0.004). CONCLUSIONS: TMG3 expression is increased in tumor tissue, also its high expression correlates with multiple tumor nodules, higher BCLC stage, abnormal AFP and reduced OS in HCC patients.

Co-existence of specific IgE antibodies and T cells reactive to house dust mites and human transglutaminase3/tropomysin in patients with atopic dermatitis.

BACKGROUND: Although specific IgE antibodies reactive to exogenous antigens are found in patients with atopic dermatitis (AD), some patients do not have such antibodies. Autoimmunity has been proposed as a possible mechanism in these patients. OBJECTIVES: To identify specific IgE antibodies reactive to human transglutaminase 3 (TG3) and tropomysin (TMP) and determine whether auto-reactive T cells are induced by these proteins in patients with AD. MATERIALS & METHODS: Forty-two patients with AD and 27 healthy controls were included in this study. IgE antibodies against recombinant human TG3 and TMP were measured by ELISA. Cross-reactivity between allergens was determined by EdU of peripheral blood mononuclear cells (PBMCs) proliferation assays. T-cell lines were generated from PBMCs in the presence of house dust mites (HDM), TG3 and TMP. TG3/TP-specific T-cell clones were generated from T-cell lines, and were characterized by antigen specificity and cytokine pattern. RESULTS: In 12 patients with anti-HDM IgE antibodies, six (50%) had anti-TG3 IgE antibody and four (33.3%) had both anti-TG3 and anti-TMP IgE antibodies. Lymphocyte proliferation was induced in 12 patients by TG3 or TMP. T-cell lines and T-cell clones from PBMCs of patients with AD who had IgE antibody reactive to HDM were fully cross-reactive with TG3 and TMP. These cell clones included both Th1 cell (producing IFN-γ) and Th2 cell (inducing IL-4) responses. TG3-and TMP-specific T-cell clones were not generated from healthy controls. CONCLUSION: Specific IgE antibody and T cell clones reactive to human TG3 and TMP were found in patients with AD, indicating that an autoimmune mechanism might contribute to AD.

TGM3 promotes epithelial-mesenchymal transition and hepatocellular carcinogenesis and predicts poor prognosis for patients after curative resection.

BACKGROUND: Prognosis of hepatocellular carcinoma (HCC) remains poor despite significant recent improvement in therapy. Recent studies have reported that transglutaminase 3 (TGM3) plays an important role in several human cancer types. However, the role of TGM3 in HCC have not been previously elucidated. METHODS: We evaluated the role of TGM3 in regulating HCC cell proliferation, migration, and invasion. We also investigated the prognostic significance of TGM3 in an HCC cohort. Finally, we explored the signalling pathways that TGM3 regulates in HCC. RESULTS: We identified TGM3 to be overexpressed in HCC compared to normal tissues. Higher expression of TGM3 predicts poor prognosis in HCC patients. TGM3 knockdown led to decreased HCC cell proliferation, invasion, and xenograft tumour growth. TGM3 depletion inhibited AKT, extracellular signal-regulated kinase (ERK), p65, and glycogen synthase kinase 3ß (GSK3ß)/ß-catenin activation, but promoted levels of cleaved caspase 3. Moreover, TGM3 knockdown cells had increased E-cadherin levels and decreased vimentin levels, suggesting that TGM3 contributes to epithelial-mesenchymal transition (EMT) in HCC. CONCLUSION: Our results suggest that TGM3 controls multiple oncogenic pathways in HCC, thereby contributing to increased cell proliferation and EMT, and TGM3 potentially enhances HCC metastasis. TGM3 may serve as a novel therapeutic target in HCC.

Transglutaminase 3 is expressed in basal cell carcinoma of the skin.

Transglutaminase 3 (TG3) belongs to a family of Ca2+-dependent enzymes which catalyse protein crosslinking. TG3 is important for proper development of the skin and hair shaft, and knock-out mice for the Tgm3 gene are sensitive to UVB-induced photodamage due to aberrations in cornified envelope formation. Loss of TG3 is reported in head and neck and oesophageal squamous cell carcinoma, yet, its expression in skin cancer has not been studied. The aim of the present study was to analyse the expression pattern of TG3 in skin cancer. TG3 expression was investigated based on immunohistochemical staining of a tissue micro-array of different types of skin cancer, as well as meta-analysis of public gene array data. Our findings demonstrated that TG3 is normally expressed in spinous/granular layers of the epidermis, but is absent in melanocytes as well as melanoma samples. As expected, its expression was absent in poorly differentiated squamous cell carcinoma of the skin. Surprisingly, we show that samples of basal cell carcinoma demonstrated strong staining for TG3 both in the cytoplasm and nucleus. Furthermore, at the mRNA level, the expression pattern of TGM3 was crucially altered in BCC, but not other types of skin cancer. These findings lead to new questions regarding TG3 involvement in basal cell carcinoma tumourigenesis. Moreover, the expression pattern of TG3 renders it a potential specific marker for basal cell carcinoma diagnosis.

Transglutaminase 3 contributes to malignant transformation of oral leukoplakia to cancer.

Oral leukoplakia (OL) is the most common premalignancy in the oral cavity. The objective of this study was to investigate the biological role of transglutaminase 3 (TGM3) in malignant transformation of OL and its clinical value for predicting oral squamous cell carcinoma (OSCC) risk in patients with OL. Immunohistochemistry was used to measure TGM3 expression in OL samples from 98 patients. Patient clinicopathological and follow-up data were analyzed. The TGM3 biological role in OL cells was investigated in gain-of-function and loss-of-function assays, and the TGM3 downregulated mechanism in OLs was characterized. TGM3 mRNA and protein expressions were frequently downregulated in OL cells and samples. DNA hypermethylation was a mechanism of TGM3 downregulation. TGM3 overexpression and silencing affected the proliferation, colony formation, and apoptosis of OL cells through apoptosis-related protein dysregulations. Lower TGM3 levels were strongly associated with the grade of epithelial dysplasia and OSCC development. Multivariate analyses showed that TGM3 was the independent predictor for malignant transformation of OL. Collectively, these data indicated that TGM3 played an important role in OL malignant transformation and may serve as a predictor to identify OL with OSCC development.

Decreased fibrinolytic potential and morphological changes of fibrin structure in dermatitis herpetiformis.

BACKGROUND: Recently, high prevalence of cryofibrinogenaemia has been observed in plasma of untreated dermatitis herpetiformis (DH) patients, and the pathological IgA and TG3 deposits in the papillary dermis were found to co-localize with fibrin and fibrinogen. OBJECTIVE: To study the fibrinolytic potential in plasma of untreated, dapsone and or/gluten-free diet treated DH patients as well as the in vitro effect of dapsone on the fibrinolytic profile. METHOD: Plasma samples of 23 DH patients, 19 healthy subjects and 5 pemphigus vulgaris patients were investigated by a turbidimetric-clot lysis assay. Out of them 5 DH plasma samples representing different fibrinolytic parameters, and 3 healthy controls were selected for parallel fibrin clot preparation. The clot fibrin structure was examined by scanning electron microscopy (SEM), and the diameters of 900 fibrin fibres were determined in each clot. RESULTS: A significantly prolonged clot lysis time was detected in untreated DH patients. The turbidity values of DH plasma clots indicated an altered fibrin structure that was also confirmed by SEM: significantly thicker fibrin fibers were observed in untreated, TG3 antibody positive DH patients compared to healthy controls, whereas the fiber diameters of dapsone-treated patients were similar or thinner than the control values. In line with the structural changes of fibrin, the fibrinolytic profile of 5 DH patients under dapsone treatment approached the control values. CONCLUSION: This study revealed that the fibrinolytic potential was impaired in the plasma of untreated DH patients, whereas dapsone corrected the fibrinolytic defect. These data suggest a pathogenic role for plasma-derived factors in the development of skin symptoms and add a new aspect to the long-known beneficial, symptomatic effect of dapsone in active DH.