Long noncoding RNA TMPO-AS1 accelerates glycolysis by regulating the miR-1270/PKM2 axis in colorectal cancer.

BACKGROUND: Long noncoding RNA thymopoietin-antisense RNA 1 (TMPO-AS1) is recognized as a participant in cancer progression. Nevertheless, its biological function in colorectal cancer remains obscure and needs further elucidation. METHODS AND RESULTS: First, we discovered enriched TMPO-AS1 in the tumor tissues that were related to poor prognosis. TMPO-AS1 knockdown enhanced SW480 cell apoptosis but inhibited invasion, proliferation, migration, and glucose metabolism. Further, MiR-1270 is directly bound with TMPO-AS1. MiR-1270 mimics were confirmed to inhibit cell proliferation, invasion, and glucose metabolism in our study. Mechanistically, miR-1270 directly is bound with the 3' untranslated regions (3'UTR) of PKM2 to downregulate PKM2. MiR-1270 inhibitors reversed the TMPO-AS1 knockdown's effect on suppressing the tumor cell proliferation, invasion, and glycolysis, while the knockdown of PKM2 further inverted the function of miR-1270 inhibitors on the TMPO-AS1 knockdown. CONCLUSIONS: This study illustrated that TMPO-AS1 advanced the development and the glycolysis of colorectal cancer by modulating the miR-1270/PKM2 axis, which provided a new insight into the colorectal cancer therapeutic strategy.

LncRNA TMPO-AS1 promotes esophageal squamous cell carcinoma progression by forming biomolecular condensates with FUS and p300 to regulate TMPO transcription.

Esophageal squamous cell carcinoma (ESCC) is one of the most life- and health-threatening malignant diseases worldwide, especially in China. Long noncoding RNAs (lncRNAs) have emerged as important regulators of tumorigenesis and tumor progression. However, the roles and mechanisms of lncRNAs in ESCC require further exploration. Here, in combination with a small interfering RNA (siRNA) library targeting specific lncRNAs, we performed MTS and Transwell assays to screen functional lncRNAs that were overexpressed in ESCC. TMPO-AS1 expression was significantly upregulated in ESCC tumor samples, with higher TMPO-AS1 expression positively correlated with shorter overall survival times. In vitro and in vivo functional experiments revealed that TMPO-AS1 promotes the proliferation and metastasis of ESCC cells. Mechanistically, TMPO-AS1 bound to fused in sarcoma (FUS) and recruited p300 to the TMPO promoter, forming biomolecular condensates in situ to activate TMPO transcription in cis by increasing the acetylation of histone H3 lysine 27 (H3K27ac). Targeting TMPO-AS1 led to impaired ESCC tumor growth in a patient-derived xenograft (PDX) model. We found that TMPO-AS1 is required for cell proliferation and metastasis in ESCC by promoting the expression of TMPO, and both TMPO-AS1 and TMPO might be potential biomarkers and therapeutic targets in ESCC.

lncRNA TMPO antisense RNA 1 promotes the malignancy of cholangiocarcinoma cells by regulating let-7g-5p/ high-mobility group A1 axis.

Cholangiocarcinoma (CHOL) is often diagnosed at an advanced stage; therefore, exploring its key regulatory factors is important for earlier diagnosis and treatment. This study aimed to identify the mechanisms of long non-coding RNA (lncRNA) TMPO Antisense RNA 1 (TMPO-AS1), microRNA let-7 g-5p, and high-mobility group A1 (HMGA1) proteins in CHOL. Our results, through quantitative real-time PCR and Western blot detection, showed that TMPO-AS1 and HMGA1 were overexpressed while let-7 g-5p was underexpressed in CHOL. Cell function experiments in CHOL cells revealed that TMPO-AS1 knockdown inhibited cell proliferation, colony formation, and cell migration, but induced apoptosis. TMPO-AS1 knockdown also suppressed tumor growth in vivo. Together with luciferase assay and Western blotting, we found that TMPO-AS1 could sponge let-7 g-5p to promote HMGA1 expression. Moreover, HMGA1 overexpression attenuated the effect of TMPO-AS1 downregulation in CHOL cells. Overall, our findings identified the oncogenic effect of TMPO-AS1 on CHOL cells, which may put forward a novel methodology for CHOL diagnosis and therapy.

Long non-coding RNA TMPO-AS1 facilitates the progression of colorectal cancer cells via sponging miR-98-5p to upregulate BCAT1 expression.

BACKGROUND AND AIM: Colorectal cancer, as a common malignant carcinoma in the gastrointestinal tract, has a high mortality globally. However, the specific molecular mechanisms of long non-coding RNA (lncRNA) thymopoietin antisense transcript 1 (TMPO-AS1) in colorectal cancer were unclear. METHODS: We tested the expression level of TMPO-AS1 via qRT-PCR in colorectal cancer cells, while the protein levels of branched chain amino acid transaminase 1 (BCAT1) and the stemness-related proteins were evaluated by western blot analysis. Colony formation, EdU staining, TUNEL, flow cytometry, and sphere formation assays were to assess the biological behaviors of colorectal cancer cells. Then, luciferase reporter, RIP, and RNA pull down assay were applied for confirming the combination between microRNA-98-5p (miR-98-5p) and TMPO-AS1/BCAT1. RESULTS: TMPO-AS1 was aberrantly expressed at high levels in colorectal cancer cells. Silenced TMPO-AS1 restrained cell proliferation and stemness and promoted apoptosis oppositely, while overexpressing TMPO-AS1 exerted the adverse effects. Furthermore, miR-98-5p was proven to a target of TMPO-AS1 inhibit cell progression in colorectal cancer. Additionally, BCAT1 was proved to enhance cell progression as the target of miR-98-5p, and it offset the effect of silenced TMPO-AS1 on colorectal cancer cells. CONCLUSION: TMPO-AS1 promotes the progression of colorectal cancer cells via sponging miR-98-5p to upregulate BCAT1 expression.

Anti-inflammation of epicatechin mediated by TMEM35A and TMPO in bovine mammary epithelial cell line cells and mouse mammary gland.

Epicatechin (EC) has significant antiinflammation, antioxidation, and anticancer activities. It also provides a new alternative treatment for mastitis, which can result in great economic losses in the dairy industry if left untreated. The purpose of this study was to investigate the anti-inflammatory effects of EC on mastitis and the underlying mechanism using in vivo and in vitro systems. The use of ELISA and immunohistochemistry assays showed that EC treatment at 1.5, 7.5, 15, and 30 mg/mL decreased protein expression of inflammatory mediators, including cyclooxygenase-2 and inducible nitric oxide synthase; inflammatory cytokines, which were composed of IL-1ß, TNF-α, and IL-6 in lipopolysaccharide (LPS)-stimulated bovine mammary epithelial cell line (MAC-T); and mouse mammary gland, together with reduced filtration of T lymphocytes in the mouse mammary gland. Furthermore, EC treatment reduced LPS-induced phosphorylation levels of p65 and inhibitor of NF-κB, and blocked nuclear translocation of p65 as revealed by western blot and immunofluorescence test in MAC-T cells and the mouse mammary gland. Epicatechin also attenuated LPS-induced phosphorylation levels of mitogen-activated protein kinase members (i.e., p38, c-Jun N-terminal kinase 1/2 and extracellular regulated protein kinases 1/2). Using RNA-seq and tandem mass tag analyses, upregulation of TMEM35A and TMPO proteins was disclosed in MAC-T cells cotreated with LPS and EC. Although clustered regularly interspaced short palindromic repeats/Cas9-based knockdown of TMEM35A and TMPO attenuated abundance of phosphorylated (p)-p65, p-p38, TNF-α, and iNOS, overexpression of TMEM35A reversed EC-mediated effects in TMPO knockdown cells. Moreover, interaction between TMEM35A and TMPO was detected using the co-immunoprecipitation method. In conclusion, our data demonstrated that EC inhibited LPS-induced inflammatory response in MAC-T cells and the mouse mammary gland. Importantly, TMEM35A mediated the transmembrane transport of EC, and the interaction between TMEM35A and TMPO inhibited MAPK and NF-κB pathways.

The Emerging Role of Thymopoietin-Antisense RNA 1 as Long Noncoding RNA in the Pathogenesis of Human Cancers.

Long noncoding RNAs (lncRNAs) play essential roles in the occurrence and development of multiple human cancers. An accumulating body of researches have investigated thymopoietin antisense RNA 1 (TMPO-AS1) as a newly discovered lncRNA, which functions as an oncogenic lncRNA that is upregulated in various human malignancies and associated with poor prognosis. Many studies have detected abnormally high expression levels of TMPO-AS1 in multiple cancers, such as lung cancer, breast cancer, colorectal cancer (CRC), hepatocellular carcinoma, CRC, gastric cancer, ovarian cancer, thyroid cancer, esophageal cancer, Wilms tumor, cervical cancer, retinoblastoma, bladder cancer, osteosarcoma, and prostate cancer. TMPO-AS1 has been subsequently demonstrated to play a pivotal role in tumorigenesis and progression. The aberrantly expressed TMPO-AS1 acts as a competing endogenous RNA (ceRNA) that inhibits miRNA expression, thus activating the expression of downstream oncogenes. This study comprehensively summarizes the aberrant expressions of TMPO-AS1 as reported in the current literature and explains the relevant biological regulation mechanisms in carcinogenesis and tumor progression. Corresponding studies have indicated that TMPO-AS1 has a potential value as a promising biomarker or a target for cancer therapy.

LncRNA TMPO-AS1 promotes proliferation and migration in bladder cancer.

OBJECTIVE: This study aims to uncover the in vitro influences of lncRNA TMPO-AS1 on the progression of bladder cancer (BLCA) and the underlying mechanism. PATIENTS AND METHODS: Expression levels of TMPO-AS1 in BLCA tissues and normal bladder tissues were analyzed in The Cancer Genome Atlas (TCGA) database. Differential expressions of TMPO-AS1 in BLCA tissues and normal bladder epithelial tissues were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Potential influence of TMPO-AS1 on prognosis of BLCA patients was assessed. In vitro influences of TMPO-AS1 on proliferative and migratory abilities in T24 and UMUC-3 cells were evaluated by Cell Counting Kit-8 (CCK-8), transwell, and wound healing assay, respectively. Finally, the correlation between TMPO-AS1 and its sense RNA TMPO was assessed by analyzing TCGA database, clinical samples, and BLCA cell lines. RESULTS: By analyzing TCGA database and clinical samples, it was found that TMPO-AS1 was upregulated in BLCA tissues compared with that in normal bladder tissues. Worse survival was observed in BLCA patients with high expression of TMPO-AS1. TMPO-AS1 level was correlated to muscle invasiveness and TNM stage of BLCA patients. In T24 and UMUC-3 cells, the knockdown of TMPO-AS1 suppressed proliferative and migratory abilities. TMPO-AS1 level was positively correlated to that of its sense RNA TMPO. Moreover, the knockdown of TMPO-AS1 downregulated mRNA and protein levels of TMPO in BLCA cells. CONCLUSIONS: TMPO-AS1 is upregulated in BLCA tissue and closely linked to poor prognosis of BLCA patients.

TMPO-AS1/miR-98-5p/EBF1 feedback loop contributes to the progression of bladder cancer.

As reported in numerous studies, long non-coding RNAs (lncRNAs) exert significant effect on the regulation of tumor development. LncRNA TMPO antisense RNA 1 (TMPO-AS1) has been confirmed to be implicated in the development of several cancers. However, its clinical significance is still largely unknown in bladder cancer (BCa). In this study, high expression of TMPO-AS1 was revealed in BCa tissues and cell lines, and TMPO-AS1 predicted poor prognosis. Moreover, TMPO-AS1 facilitated cell growth. Additionally, TMPO-AS1 also boosted the migration and invasion of BCa cells. Mechanistically, overexpressed EBF transcription factor 1 (EBF1) in BCa cell was verified to promote the transcription of TMPO-AS1. Later, we found that TMPO-AS1 was a cytoplasmic RNA and could sponge miR-98-5p. Besides, it was validated that EBF1 is a target gene of miR-98-5p and negatively correlated with miR-98-5p in terms of expression level. According to the results of rescue experiments, we observed that EBF1 overexpression restored the repressive effect of TMPO-AS1 silencing on BCa development. Our research is the first to disclose the biological role and molecular mechanism of TMPO-AS1 in BCa, and TMPO-AS1 might be identified as a new therapeutic target for BCa patients.

Long noncoding RNA TMPO-AS1 promotes lung adenocarcinoma progression and is negatively regulated by miR-383-5p.

Long noncoding RNAs (lncRNAs) play critical roles in the pathogenesis of various diseases, including a variety of tumors. Nevertheless, its functional roles and underlying molecular basis for their dysregulation in lung adenocarcinoma (LUAD) are largely unknown. Herein, in our study, we identified that lncRNA TMPO-AS1 is significantly upregulated in LUAD tissues and cell lines. Knockdown of TMPO-AS1 remarkably suppressed LUAD cell growth, induced apoptosis as well as G1/S arrest, and inhibited LUAD cell invasion, whereas overexpression of TMPO-AS1 exerts the opposite effects. Next, we implemented online database analysis tools to find that mir-383-5p could target TMPO-AS1, and our data showed that TMPO-AS1 was negatively correlated with mir-383-5p in LUAD specimens. We found that inhibiting miR-383-5p expression led to a marked upregulation of TMPO-AS1 level, while overexpression of miR-383-5p markedly suppressed TMPO-AS1's expression and function, suggesting that TMPO-AS1 is negatively regulated by miR-383-5p. In addition, we confirmed that miR-383-5p directly targeted TMPO-AS1 by binding to microRNA binding sites in the TMPO-AS1 sequence with a luciferase reporter and RIP assays. Besides, the inhibition of TMPO-AS1 significantly suppressed the tumorigenesis ability of LUAD cells in vivo. Together, these results demonstrate that TMPO-AS1 could be considered as a potential therapeutic target for LUAD patients.

LncRNA TMPO-AS1 serves as a ceRNA to promote osteosarcoma tumorigenesis by regulating miR-199a-5p/WNT7B axis.

Osteosarcoma (OS) is a common kind of aggressive tumor in bone which was mostly identified in children and adolescents with extremely high risk of death. Accumulating research works have displayed that long noncoding RNAs (lncRNAs) exert an essential role in the development of multiple cancers. It has been reported that TMPO-AS1 is an oncogene in cancers; nonetheless, its molecular mechanism in OS is totally unclear. Our present study elucidated that a remarkable overexpression of TMPO-AS1 was found in OS tissues and cells. Moreover, TMPO-AS1 depletion restrained Wnt/ß-catenin pathway and cell proliferation as well as facilitated cell apoptosis. Further molecular mechanism investigations showed that TMPO-AS1 can sponge to miR-199a-5p. Moreover, miR-199a-5p was at a low level at OS cells. Importantly, miR-199a-5p's overexpression was associated with the OS cells' decreased proliferation and increased apoptosis. In addition, WNT7B was confirmed as a downstream gene of miR-199a-5p. Also the WNT7B expression was reversely modulated by miR-199a-5p and positively modulated by TMPO-AS1. Rescue experiments suggested that downregulated WNT7B rescued miR-199a-5p inhibitor-mediated repression on OS progression, but the treatment of LiCl counteracted the effect of WNT7B downregulation. In a word, TMPO-AS1 serves as a competing endogenous RNA to boost osteosarcoma tumorigenesis by regulating miR-199a-5p/WNT7B axis, which provided an underlying therapeutic target for patients with OS.

[Proliferation inhibition and apoptosis promotion induced by deletion of TMPO in A549].

Objective: To investigate the effect of thymopoietin (TMPO) gene deleted by small interfering RNA (RNAi) on the proliferation and apoptosis of lung cancer cell A549 and its mechanism. Methods: TMPO siRNA was transfected into A549 cells by lipofection. The transfected siRNA control was used as a negative control, and the parent cells were used as blank control. Forty-eight hours later, the expression of TMPO in the transfected cells was detected by real-time fluorescent quantitative polymerase chain reaction (RT-PCR) and Western blot. Cell proliferation was detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) assay, cell cycle and apoptosis were detected by flow cytometry, the protein levels of proliferating cell nuclear antigen (PCNA), cleaved caspase-3, notch receptor 1 (Notch1) and mammalian rapamycin target protein (mTOR) were detected by Western blot analysis. Results: The results of RT-PCR and Western blot showed that the expression levels of TMPO mRNA in the blank control group, the negative control group and TMPO siRNA transfected group were (1.01±0.11), (0.99±0.10), (0.36±0.04), respectively, the protein levels were (0.27±0.02), (0.29±0.03), (0.08±0.10), respectively. The expression levels of TMPO mRNA and protein in the transfected group were significantly lower than those in the blank control and negative control group (P<0.05). The results of MTT assay showed that the OD values of the blank control group, the negative control group and the transfected group were (0.35±0.04), (0.37±0.04) and (0.34±0.03) at 24 h of transfection, respectively. The OD values at 48 h were (0.47±0.06), (0.46±0.08), (0.37±0.04), the OD values at 72 h were (0.75±0.08), (0.73±0.07), (0.49±0.05), respectively, and the OD values at 96 h were (1.09±0.07), (1.06±0.08), (0.56±0.06). The proliferation abilities of the transfected cells at 48, 72, 96 h were significantly lower than those of the blank control and the negative control group (P<0.05). The results of flow cytometry showed that the proportion of G(0)/G(1) phase cells in blank control group, negative control group and transfection group were (62.55±2.03)%, (61.24±3.15)%, (47.35±2.44)%, respectively. The proportion of cells in S phase were (17.12±1.31)%, (17.70±2.01)%, and (20.81±2.06)%, respectively. The proportion of cells in G(2)/M phase were (20.33±1.43)%, (21.06±1.52)%, (31.84±2.76)%, respectively. The proportion of cells in G(0)/G(1) phase of transfection group was significantly lower than those of blank control and negative control group (P<0.05). The proportion of cells in G(2)/M phase of transfection group was significantly higher than those of blank control and negative control group (P<0.05). The apoptosis ratio of the transfection group was (34.10±2.69)%, significantly higher than (2.96±0.03)% of the blank control and (3.01±0.04)% of the negative control group (P<0.05). Western blot analysis showed that PCNA, Notch1 and mTOR proteins were down-regulated while cleaved caspase-3 protein was up-regulated in A549 cells after deletion of TMPO. Conclusion: The inhibition of TMPO gene expression induced by small interfering RNA can significantly inhibit the proliferation and induce apoptosis of A549 cells, and the mechanism is associated with the inhibition of the activation of Notch1/mTOR signaling pathway.

TMPO-AS1 promotes cervical cancer progression by upregulating RAB14 via sponging miR-577.

BACKGROUND: Accumulating evidence has shown that long non-coding RNAs play a key role in cancer initiation and development. However, the effect of TMPO antisense RNA 1 (TMPO-AS1) on the progression of cervical cancer (CC) remains to be determined. METHODS: The mRNA expression of TMPO-AS1, miR-577 and RAB14 was measured by a quantitative reverse transcriptase-polymerase chain reaction. The protein level of RAB14 was detected by western blotting. The function of TMPO-AS1 in CC was measured via Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine and transwell assays, as well as by flow cytometry analysis. Nuclear-cytoplasmic fractionation and RNA-fluorescence in situ hybridization validated the subcellular position of TMPO-AS1. An interaction between miR-577 and TMPO-AS1 or RAB14 was confirmed by luciferase reporter, RNA pull-down and RNA immunoprecipitation assays. RESULTS: TMPO-AS1 was highly expressed in CC. In addition, TMPO-AS1 knockdown inhibited proliferation and migration, and also induced apoptosis. TMPO-AS1 located in the cytoplasm and promoted RAB14 expression by absorbing miR-577. RAB14 overexpression or miR-577 knockdown restored the suppressing effect of TMPO-AS1 knockdown on the biological behavior of CC cells. CONCLUSIONS: The present study has revealed a novel TMPO-AS1/miR-577/RAB14 regulatory axis in the pathogenesis of CC, highlighting TMPO-AS1 as a promising therapeutic target for CC patients.

ESR1-Stabilizing Long Noncoding RNA TMPO-AS1 Promotes Hormone-Refractory Breast Cancer Progression.

Acquired endocrine therapy resistance is a significant clinical problem for breast cancer patients. In recent years, increasing attention has been paid to long noncoding RNA (lncRNA) as a critical modulator for cancer progression. Based on RNA-sequencing data of breast invasive carcinomas in The Cancer Genome Atlas database, we identified thymopoietin antisense transcript 1 (TMPO-AS1) as a functional lncRNA that significantly correlates with proliferative biomarkers. TMPO-AS1 positivity analyzed by in situ hybridization significantly correlates with poor prognosis of breast cancer patients. TMPO-AS1 expression was upregulated in endocrine therapy-resistant MCF-7 cells compared with levels in parental cells and was estrogen inducible. Gain and loss of TMPO-AS1 experiments showed that TMPO-AS1 promotes the proliferation and viability of estrogen receptor (ER)-positive breast cancer cells in vitro and in vivo Global expression analysis using a microarray demonstrated that TMPO-AS1 is closely associated with the estrogen signaling pathway. TMPO-AS1 could positively regulate estrogen receptor 1 (ESR1) mRNA expression by stabilizing ESR1 mRNA through interaction with ESR1 mRNA. Enhanced expression of ESR1 mRNA by TMPO-AS1 could play a critical role in the proliferation of ER-positive breast cancer. Our findings provide a new insight into the understanding of molecular mechanisms underlying hormone-dependent breast cancer progression and endocrine resistance.

Long noncoding RNA TMPO-AS1 promotes progression of non-small cell lung cancer through regulating its natural antisense transcript TMPO.

Long noncoding RNAs (lncRNAs), a large group of RNAs with limited or no protein-coding capacity, have been demonstrated to play critical roles in human malignancy. The aim of this study is to examine the expression and function TMPO antisense transcript 1 (TMPO-AS1) in non-small cell lung cancer (NSCLC). Here, we found that the expression of both TMPO-AS1 and TMPO mRNA levels were overexpressed in NSCLC cells lines and tissues. A significant positive correlation was observed between TMPO-AS1 and TMPO mRNA levels. The upregulation of TMPO-AS1, TMPO mRNA and protein levels were associated with tumor progression of NSCLC. More importantly, through antisense pairing with TMPO mRNA, TMPO-AS1 regulates TMPO mRNA stability. Knockdown of TMPO-AS1 decreased the mRNA and protein levels of TMPO in NSCLC cells. An overlapping (OL) region was found between TMPO-AS1 and TMPO exon 1 and overexpression of TMPO-AS1-OL elevated the mRNA and protein levels of TMPO. Functionally, the downregulation of TMPO-AS1 significantly inhibited cells proliferation, colony formation, migration and invasiveness in vitro, and tumor growth in vivo. In contrast, overexpression of TMPO could promote the aggressive behaviors of NSCLC cells in vitro. Our findings indicate that TMPO-AS1 contributes to lung carcinogenesis, which may be partially through upregulation TMPO.

Depletion of thymopoietin inhibits proliferation and induces cell cycle arrest/apoptosis in glioblastoma cells.

BACKGROUND: Glioblastoma (GBM) is the most malignant nervous system tumor with an almost 100 % recurrence rate. Thymopoietin (TMPO) has been demonstrated to be upregulated in various tumors, including lung cancer, breast cancer, and so on, but its role in GBM has not been reported. This study was aimed to determine the role of TMPO in GBM. METHODS: Publicly available Oncomine dataset analysis was used to explore the expression level of TMPO in GBM specimens. Then the expression of TMPO was knocked down in GBM cells using lentiviral system, and the knockdown efficacy was further validated by real-time quantitative PCR and western blot analysis. Furthermore, the effects of TMPO silencing on GBM cell proliferation and apoptosis were examined by MTT, colony formation, and flow cytometry analysis. Meanwhile, the expression of apoptotic markers caspase-3 and poly(ADP-ribose) polymerase (PARP) were investigated by western blot analysis. RESULTS: This study observed that the expression of TMPO in GBM specimens was remarkably higher than that in normal brain specimens. Moreover, knockdown of TMPO could significantly inhibit cell proliferation and arrest cell cycle progression at the G2/M phase. It also found that TMPO knockdown promoted cell apoptosis by upregulation of the cleavage of caspase-3 and PARP protein levels which are the markers of apoptosis. CONCLUSIONS: The results suggested TMPO might be a novel therapeutic target for GBM.

Thymopoietin Beta and Gamma Isoforms as a Potential Diagnostic Molecular Marker for Breast Cancer: Preliminary Data.

Thymopoietin (TMPO) is an inner nuclear membrane protein, the coding gene named equally, can give arise to six isoforms by alternative splicing. This gene has been found up regulated in several types of cancer. At present work, we evaluated the TMPO isoforms generated by alternative splicing as well as the protein signal detection in breast cancer samples. TMPO expression was analyzed by immunohistochemistry in tissue microarray containing 46 breast tissue samples including normal (n = 6), benign lesions (n = 18) (fibroadenomas (n = 6), fibrocystic changes (n = 6), ductal hyperplasias (n = 6)) and breast carcinoma (n = 22). Isoforms -α, -ß and -γ of TMPO were evaluated using RT-PCR; clinical-pathological correlation analysis were done by mean of X(2). Neither the normal nor the benign lesions of the breast showed positive TMPO immunodetection, whilst 45 % of the breast carcinomas were immunopositive (p = 0.000), nine of ten positives carcinomas correspond to the Luminal A subtype. Further, alpha isoform was present in all breast samples analyzed; however, beta and gamma isoforms were only present in ten (p = 0.003) and 17 (p = 0.000), respectively, in the breast cancer samples. According with the present data, we suggest that TMPOß and -γ isoforms could provide a potential reliable diagnostic marker for breast cancer.

Contribution of SUN1 mutations to the pathomechanism in muscular dystrophies.

Mutations in several genes encoding nuclear envelope (NE) associated proteins cause Emery-Dreifuss muscular dystrophy (EDMD). We analyzed fibroblasts from a patient who had a mutation in the EMD gene (p.L84Pfs*6) leading to loss of Emerin and a heterozygous mutation in SUN1 (p.A203V). The second patient harbored a heterozygous mutation in LAP2alpha (p.P426L) and a further mutation in SUN1 (p.A614V). p.A203V is located in the N-terminal domain of SUN1 facing the nucleoplasm and situated in the vicinity of the Nesprin-2 and Emerin binding site. p.A614V precedes the SUN domain, which interacts with the KASH domain of Nesprins in the periplasmic space and forms the center of the LINC complex. At the cellular level, we observed alterations in the amounts for several components of the NE in patient fibroblasts and further phenotypic characteristics generally attributed to laminopathies such as increased sensitivity to heat stress. The defects were more severe than observed in EDMD cells with mutations in a single gene. In particular, in patient fibroblasts carrying the p.A203V mutation in SUN1, the alterations were aggravated. Moreover, SUN1 of both patient fibroblasts exhibited reduced interaction with Lamin A/C and when expressed ectopically in wild-type fibroblasts, the SUN1 mutant proteins exhibited reduced interactions with Emerin as well.

mRNA retrotransposition coupled with 5' inversion as a possible source of new genes.

Human long interspersed nuclear element-1 (L1) occupies one-sixth of our genome and has contributed to genome evolution in various ways. Approximately 10% of human L1 copies are composed of two L1 segments; the 5' segment and 3' segment are in head-to-head (i.e., 5'-inverted) orientation. Besides mediating their own retrotransposition, L1 has the ability to mobilize mRNA "in trans," and the number of retrotransposed mRNA sequences (retrocopies) is estimated to be >6,000. In this study, we identified 48 human-specific retrocopies and 95 chimpanzee-specific retrocopies by comparing the human and chimpanzee genomes. Among these retrocopies, 12 were 5'-inverted. The characteristics of these 5'-inverted retrocopies were similar to those of 5'-inverted L1 copies, indicating that the 5' inversion is generated by the same mechanism. With these findings, we examined the possibility that 5' inversion of the retrocopy generates a new gene that codes for a peptide with a different N terminus. We identified several potential 5'-inverted retrogenes, including those of thymopoietin beta (TMPO) and eukaryotic translation initiation factor 3 subunit 5 (EIF3F). The most interesting candidate was the 5'-inverted retrocopy of small nuclear ribonucleoprotein polypeptide N (SNRPN). This retrocopy was transcribed in the reverse orientation in several organs, had multiple transcript variants, and encoded a protein containing a peptide fragment derived from the N-terminal portion of SNRPN. Our results suggest that mRNA retrotransposition coupled with 5' inversion may be a mechanism to generate new genes distinct from parental genes.

Identification of tyrosine-phosphorylation sites in the nuclear membrane protein emerin.

Although several proteins undergo tyrosine phosphorylation at the nuclear envelope, we achieved, for the first time, the identification of tyrosine-phosphorylation sites of a nuclear-membrane protein, emerin, by applying two mass spectrometry-based techniques. With a multiprotease approach combined with highly specific phosphopeptide enrichment and nano liquid chromatography tandem mass spectrometry analysis, we identified three tyrosine-phosphorylation sites, Y-75, Y-95, and Y-106, in mouse emerin. Stable isotope labeling with amino acids in cell culture revealed phosphotyrosines at Y-59, Y-74, Y-86, Y-161, and Y-167 of human emerin. The phosphorylation sites Y-74/Y-75 (human/mouse emerin), Y-85/Y-86, Y-94/Y-95, and Y-105/Y-106 are located in regions previously shown to be critical for interactions of emerin with lamin A, actin or the transcriptional regulators GCL and Btf, while the residues Y-161 and Y-167 are in a region linked to binding lamin-A or actin. Tyrosine Y-94/Y-95 is located adjacent to a five-residue motif in human emerin, whose deletion has been associated with X-linked Emery-Dreifuss muscle dystrophy.