Expression of TIP30 tumor suppressor gene is down-regulated in human colorectal carcinoma

Investigating TIP30-Mediated regulation of mTORC1 signaling as a therapeutic strategy for coxsackievirus B3-Induced viral myocarditis

This study aims to elucidate the role of TIP30 (30 KDa HIV-1 TAT-Interacting Protein) in the progression of coxsackievirus B3 (CVB3)-induced viral myocarditis. TIP30 knockout and wildtype mice were intraperitoneally infected with CVB3 and evaluated at day 7 post-infection. HeLa cells were transfected with TIP30 lentiviral particles and subsequently infected with CVB3 to evaluate viral replication, cellular pathogenesis, and mechanistic target of rapamycin complex 1 (mTORC1) signaling. Deletion of the TIP30 gene heightened heart virus titers and mortality rates in mice with CVB3-induced myocarditis, exacerbating cardiac damage and fibrosis, and elevating pro-inflammatory factors level. In vitro experiments demonstrated the modulation of mTORC1 signaling by TIP30 during CVB3 infection in HeLa cells. TIP30 overexpression mitigated CVB3-induced cellular pathogenesis and VP1 expression, with rapamycin, an mTOR1 inhibitor, reversing these effects. These findings suggest TIP30 plays a critical protective role against CVB3-induced myocarditis by regulating mTORC1 signaling.

Integrative analysis of the DNA methylome and transcriptome in uterine leiomyoma shows altered regulation of genes involved in metabolism, proliferation, extracellular matrix and vesicles

Uterine leiomyomas are the most common benign tumors in women of reproductive age. Despite the high prevalence, tumor pathology remains unclear, which hampers development of safe and effective treatments. Epigenetic mechanisms appear to be involved in uterine leiomyoma development, particularly via DNA methylation that regulates gene expression. We aimed to determine the relationship between DNA methylation and gene expression in uterine leiomyoma compared to adjacent myometrium to identify molecular mechanisms involved in uterine leiomyoma formation that are under epigenetic control. Our results showed a different DNA methylation profile between uterine leiomyoma and myometrium, leading to hypermethylation of uterine leiomyoma, and a different global transcriptome profile. Integration of DNA methylation and whole-transcriptome RNA-sequencing data identified 93 genes regulated by methylation, with 22 hypomethylated/upregulated and 71 hypermethylated/downregulated. Functional enrichment analysis showed dysregulated biological processes and molecular functions involved in metabolism and cell physiology, response to extracellular signals, invasion, and proliferation, as well as pathways related to uterine biology and cancer. Cellular components such as cell membranes, vesicles, extracellular matrix, and cell junctions were dysregulated in uterine leiomyoma. In addition, we found hypomethylation/upregulation of oncogenes (PRL, ATP8B4, CEMIP, ZPMS2-AS1, RIMS2, TFAP2C) and hypermethylation/downregulation of tumor suppressor genes (EFEMP1, FBLN2, ARHGAP10, HTATIP2), which are related to proliferation, invasion, altered metabolism, deposition of extracellular matrix, and Wnt/β-catenin pathway dysregulation. This confirms that key processes of uterine leiomyoma development are under DNA methylation control. Finally, inhibition of DNA methyltransferases by 5-aza-2'-deoxycitidine increased expression of hypermethylated/downregulated genes in uterine leiomyoma cells in vitro. In conclusion, gene regulation by DNA methylation is implicated in uterine leiomyoma pathogenesis, and reversion of this methylation could offer a therapeutic option for uterine leiomyoma. This article is protected by copyright. All rights reserved.

Absence of HTATIP2 Expression in A549 Lung Adenocarcinoma Cells Promotes Tumor Plasticity in Response to Hypoxic Stress

HIV-1 Tat Interactive Protein 2 (HTATIP2) is a tumor suppressor, of which reduced or absent expression is associated with increased susceptibility to tumorigenesis and enhanced tumor invasion and metastasis. However, whether the absent expression of HTATIP2 is a tumor-promoting factor that acts through improving tumor adaptation to hypoxia is unclear. Here, we established a stable HTATIP2-knockdown A549 human lung adenocarcinoma cell line (A549shHTATIP2) using lentiviral-delivered HTATIP2-targeting short hairpin RNA (shRNA), employed a double subcutaneous xenograft model and incorporated photoacoustic imaging and metabolomics approaches to elucidate the impact of the absent HTATIP2 expression on tumor response to hypoxic stress. Results from the in vivo study showed that A549shHTATIP2 tumors exhibited accelerated growth but decreased intratumoral oxygenation and angiogenesis and reduced sensitivity to sorafenib treatment as compared with their parental counterparts. Moreover, results of the immunoblot and real-time PCR analyses revealed that the HIF2α protein and mRNA levels in vehicle-treated A549shHTATIP2 tumors were significantly increased (p < 0.01 compared with the parental control tumors). Despite the strong HIF2α-c-Myc protein interaction indicated by our co-immunoprecipitation data, the increase in the c-Myc protein and mRNA levels was not significant in the A549shHTATIP2 tumors. Nonetheless, MCL-1 and β-catenin protein levels in A549shHTATIP2 tumors were significantly increased (p < 0.05 compared with the parental control tumors), suggesting an enhanced β-catenin/c-Myc/MCL-1 pathway in the absence of HTATIP2 expression. The finding of significantly decreased E-cadherin (p < 0.01 compared with vehicle-treated A549shHTATIP2 tumors) and increased vimentin (p < 0.05 compared with sorafenib-treated A549 tumors) protein levels in A549shHTATIP2 tumors implicates that the absence of HTATIP2 expression increases the susceptibility of A549 tumors to sorafenib-activated epithelial-mesenchymal transition (EMT) process. Comparison of the metabolomic profiles between A549 and A549shHTATIP2 tumors demonstrated that the absence of HTATIP2 expression resulted in increased tumor metabolic plasticity that enabled tumor cells to exploit alternative metabolic pathways for survival and proliferation rather than relying on glutamine and fatty acids as a carbon source to replenish TCA cycle intermediates. Our data suggest a mechanism by which the absent HTATIP2 expression modulates tumor adaptation to hypoxia and promotes an aggressive tumor phenotype by enhancing the HIF2α-regulated β-catenin/c-Myc/MCL-1 signaling, increasing the susceptibility of tumors to sorafenib treatment-activated EMT process, and improving tumor metabolic plasticity.

Malathion induced cancer-linked gene expression in human lymphocytes

BACKGROUND

Malathion is the most widely used organophosphate pesticide in agriculture. Increasing cancer incidence in agricultural workers and their children links to the exposure of malathion. Identification of genes involved in the process of carcinogenesis is essential for exploring the role of malathion. The alteration in gene expression by malathion in human lymphocytes has not been explored yet, although hematological malignancies are rampant in humans.

OBJECTIVE

This study investigates the malathion induced expression of cancer associated genes in human lymphocytes.

METHODS

Human lymphocyte viability and colony-forming ability were analyzed in malathion treated and control groups. Gene expression profile in control and malathion treated human lymphocytes were performed using a microarray platform. The genes which have significant functions and those involved in different pathways were analyzed using the DAVID database. Differential gene expression upon malathion exposure was validated by quantitative real-time (qRT)-PCR.

RESULTS

Malathion caused a concentration-dependent reduction in human lymphocyte viability. At low concentration (50 μg/mL) of malathion treatment, human lymphocytes were viable indicating that low concentration of malathion is not cytotoxic and induces the colony formation. Total of 659 genes (15%) were up regulated and 3729 genes (85%) were down regulated in malathion treated human lymphocytes. About 57 cancer associated genes related to the growth and differentiation of B and T cells, immunoglobulin production, haematopoiesis, tumor suppression, oncogenes and signal transduction pathways like MAPK and RAS were induced by malathion.

CONCLUSION

This study evidences the carcinogenic nature of malathion. Low concentration of this pesticide is not cytotoxic and induces differentially regulated genes in human lymphocytes, which are involved in the initiation, progression, and pathogenesis of cancer.

Low TIP30 Protein Expression is Associated with a High Risk of Metastasis and Poor Prognosis for Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) is a deadly malignancy with a high prevalence worldwide. A reliable biomarker that can predict the prognosis is required to determine the therapeutic strategy. TIP30 was first identified as a tumor suppressor. A number of mechanistic studies indicated that the downregulation of TIP30 enhances the stemness, migration and survival of NSCLC cells. However, the clinical relevance of TIP30 for the prognosis of NSCLC is unknown. From a meta-analysis of public microarray datasets, we showed the upregulation of TIP30 mRNA expression was associated with worse overall survival of NSCLC patients, which contradicted the tumor suppressive role of TIP30. It is worth noting that the TIP30 mRNA expression was not correlated with its protein expression in 15 NSCLC cell lines. The results from the immunohistochemistry of a tissue microarray showed the downregulation of the TIP30 protein expression was associated with a higher risk of metastasis. In addition, the decrease in TIP30 protein was correlated with worse overall and progression-free survival of the NSCLC patients. Multivariate analysis suggested the loss of TIP30 protein was an independent factor to predict the poor prognosis of NSCLC. Our data indicated that TIP30 protein, not mRNA, would be a potential prognostic biomarker of NSCLC.

Human immunodeficiency virus Tat-TIP30 interaction promotes metastasis by enhancing the nuclear translocation of Snail in lung cancer cell lines

Lung cancer patients with human immunodeficiency virus (HIV) have a poorer prognosis than do patients without HIV infection. HIV1 Tat is a secreted viral protein that penetrates the plasma membrane and interacts with a number of proteins in non‐HIV‐infected cells. The loss of function of Tat‐interacting protein 30 (TIP30) has been linked to metastasis in non‐small cell lung cancer (NSCLC). However, it is unknown how the interaction of HIV1 Tat with TIP30 regulates the metastasis of NSCLC cells. In this study, the overexpression of TIP30 decreased tumor growth factor‐β‐induced epithelial‐to‐mesenchymal transition (EMT) and invasion of NSCLC cells, whereas the knockdown of TIP30 promoted EMT, invasion and stemness. Exposure to recombinant HIV1 Tat proteins promoted EMT and invasion. A mechanistic study showed that the interaction of HIV1 Tat with TIP30 blocked the binding of TIP30 to importin‐β, which is required for the nuclear translocation of Snail. Indeed, the loss of TIP30 promoted the nuclear translocation of Snail. In vivo studies demonstrated that the overexpression of TIP30 inhibited the metastasis of NSCLC cells. In contrast, the coexpression of HIV1 Tat and TIP30 diminished the inhibitory effect of TIP30 on metastasis. Immunohistochemistry confirmed that TIP30 overexpression reduced the nuclear localization of Snail, whereas the coexpression of HIV1 Tat and TIP30 increased nuclear Snail in metastatic tumors. In conclusion, the binding of HIV1 Tat to TIP30 enhanced EMT and metastasis by regulating the nuclear translocation of Snail. Targeting Tat‐interacting proteins may be a potential therapeutic strategy to prevent metastasis in NSCLC patients with HIV infection.

Reduction of Tat-interacting Protein 30 Expression Could be a Prognostic Marker in Bladder Urothelial Cancer

Background:

Tat-interacting protein 30 (TIP30) has been reported to be a tumor suppressor, with reduced or absent expression in various tumors. However, its role in bladder urothelial cancer (BUC) has not been investigated. Therefore, herein, we investigated the expression of TIP30 protein in BUC and normal bladder mucosa and the clinical significance of TIP30 expression in the prognosis of BUC.

Methods:

We reviewed data from 79 cases of BUC and 15 adjacent tissue samples from 79 patients treated at our institution between 2004 and 2007. TIP30 expression was examined by immunohistochemistry. The relationship between TIP30 expression and tumor stage, histological grade, and survival was analyzed. Differences between groups were evaluated using the t-test or matched-pairs test, and differences in the survival rates were analyzed with the log-rank test.

Results:

TIP30 protein expression was significantly reduced in BUC tissue (t = −6.91, P < 0.05) compared with normal tissue samples, and in invasive bladder cancer (t = 10.89, P < 0.05) compared with superficial bladder cancer. TIP30 protein expression differed significantly among different differentiated groups classified either according to the World Health Organization (2004, F = 17.48, P < 0.01) or World Health Organization (1973, F = 10.68, P < 0.01). TIP30 protein expression was significantly reduced in high-grade papillary urothelial carcinoma compared with papillary urothelial neoplasm of low malignant potential (P < 0.05) and low-grade papillary urothelial carcinoma (P < 0.05). Meanwhile, TIP30 protein expression was significantly reduced in Grade III BUC, compared with Grade I (P < 0.05) and Grade II (P < 0.05). Patients with low TIP30 expression showed a higher incidence of disease progression than those with high TIP30 expression (t = 2.63, P < 0.05). Kaplan-Meier survival analysis showed a strong positive relationship between TIP30 expression and overall survival (OS) (χ² = 17.29, P < 0.05).

Conclusions:

TIP30 expression was associated with clinical tumor stage in BUC, suggesting that it might play an important role in disease progression. Furthermore, TIP30 might predict postoperative OS. Thus, its evaluation might be useful for predicting prognosis.

Aberrant methylation of HTATIP2 and UCHL1 as a predictive biomarker for cholangiocarcinoma

Cholangiocarcinoma (CCA) is the most common primary liver cancer in Northeastern Thailand where liver fluke infection is highly endemic. Although aberrant DNA methylation in CCA has been reported by several investigators, little is known regarding the associations between them. In the present study, the results obtained from our previously published methylation array were analyzed and 10 candidate genes involved in DNA repair [protein phosphatase 4 catalytic subunit (PPP4C)], apoptosis [runt related transcription factor 3 (RUNX3), interferon regulatory factor 4 (IRF4), ubiquitin C‑terminal hydrolase L1 (UCHL1) and tumor protein p53 inducible protein 3 (TP53I3)], cell proliferation [cyclin D2 (CCND2) and Ras association domain family member 1 (RASSF1)], drug metabolism [aldehyde dehydrogenase 1 family member A3 (ALDH1A3) and solute carrier family 29 member 1 (SLC29A1)] and angiogenesis [human immunodeficiency virus‑1 tat interactive protein 2 (HTATIP2)] were selected for quantification of their methylation levels in 54 CCA and 19 adjacent normal tissues using methylation‑sensitive high‑resolution melting. The associations between the methylation status of the individual genes and clinical parameters were statistically analyzed. High methylation levels were observed in UCHL1, IRF4, CCND2, HTATIP2 and TP53I3. The median methylation level of UCHL1 was 57.3% (range, 3.15 to 88.7%) and HTATIP2 was 13.6% (range, 7.5 to 36.7%). By contrast, low methylation of HTATIP2 and UCHL1 was identified in adjacent normal tissues. The methylation status of HTATIP2 and UCHL1 was associated with patients' overall survival. CCA patients with high methylation of HTATIP2 and low methylation of UCHL1 exhibited longer overall survival. In addition, multivariate Cox regression analysis demonstrated that UCHL1 methylation was an independent factor for CCA with hazard ratio of 1.81 (95% confidence interval, 1.01‑3.25) in high methylation group. The combination of HTATIP2 and UCHL1 methylation status strongly supported their potential predictive biomarker in which patients with CCA who had high methylation of HTATIP2 and low methylation of UCHL1 showed longer overall survival than those with low HTATIP2 methylation and high UCHL1 methylation. In conclusion, the present study revealed the value of aberrant DNA methylation of HTATIP2 and UCHL1, which may serve as a potential predictive biomarker for CCA.

TET1 Depletion Induces Aberrant CpG Methylation in Colorectal Cancer Cells

Aberrant DNA methylation is commonly observed in colorectal cancer (CRC), but the underlying mechanism is not fully understood. 5-hydroxymethylcytosine levels and TET1 expression are both reduced in CRC, while epigenetic silencing of TET1 is reportedly associated with the CpG island methylator phenotype. In the present study, we aimed to clarify the relationship between loss of TET1 and aberrant DNA methylation in CRC. Stable TET1 knockdown clones were established using Colo320DM cells, which express high levels of TET1, and HCT116 cells, which express TET1 at a level similar to that in normal colonic tissue. Infinium HumanMethylation450 BeadChip assays revealed increased levels of 5-methylcytosine at more than 10,000 CpG sites in TET1-depleted Colo320DM cells. Changes in DNA methylation were observed at various positions within the genome, including promoters, gene bodies and intergenic regions, and the altered methylation affected expression of a subset of genes. By contrast, TET1 knockdown did not significantly affect DNA methylation in HCT116 cells. However, TET1 depletion was associated with attenuated effects of 5-aza-2’-deoxycytidine on gene expression profiles in both cell lines. These results suggest that loss of TET1 may induce aberrant DNA methylation and may attenuate the effect of 5-aza-2’-deoxycytidine in CRC cells.

TIP30: A Novel Tumor-Suppressor Gene

TIP30/CC3 was first identified and characterized as a "candidate" tumor-suppressor gene in 1997. Recently, the TIP30 tumor-suppressor status has been fully established since several studies have described that TIP30 protein expression is frequently downregulated in diverse types of human tumors, and the downregulation is often associated with tumor progression. TIP30 is involved in the control of cell apoptosis, growth, metastasis, angiogenesis, DNA repair, and tumor cell metabolism. Moreover, TIP30(-/-) mice spontaneously develop hepatocellular carcinoma and other tumors at a higher incidence than that of wild-type mice. In this review, we provide an overview of current knowledge concerning the role of TIP30 in tumor development and progression. To our knowledge, this is the first review about the role of novel tumor-suppressor gene TIP30 in tumor development and progression.

Association of TIP30 expression and prognosis of hepatocellular carcinoma in patients with HBV infection

Altered expression of TIP30, a tumor suppressor, has been observed in many cancers. In this study, we have evaluated the expression of TIP30 in the tissues of 209 hepatocellular carcinomas (HCC) and their adjacent tissues by using a high‐density tissue microarray, and analyzed its correlation with the clinical pathological parameters of the patients. The results revealed negative or weak expression of TIP30 in 43.5% (91/209) of the HCC tissues, and in only 27% (56/209) of the adjacent tissues. The expression level of TIP30 in HCC was inversely correlated with serum alpha‐fetoprotein (AFP) levels, HBV infection, and tumor differentiation. Multivariate analysis for survival indicated that serum HBV infection was the most significant predictor of poor prognosis in HCC (P = 0.0023), and TIP30 expression and tumor differentiation were also independent indicators in this respect (P = 0.0364 and P = 0.0397, respectively). Patients with medium or high expression levels of TIP30 (TIP30^++/+++) had a better 5‐year overall survival rate than those with low/negative (TIP30^+/−) expression (P < 0.001). TIP30^+/−/HBV⁺ patients had the worst 5‐year overall survival rate, whereas TIP30^++/+++/HBV⁻ patients had the best. To further explore the correlation between TIP30 and HBV infection in HCC, HBV⁺ hepatoblastoma cell‐line HepG2 2.2.15 and HCC cell‐line Hep3B were used. Upon silencing of HBV, we observed an upregulation of TIP30 and decreased cell proliferation. In the in vivo studies, we found that the mice inoculated with HepG2 2.2.15 cells with HBV silencing had a prolonged tumor latency and a longer life span, as compared to the control mice inoculated with untreated control cells. In conclusion, the results suggest that downregulation of TIP30 may result from HBV infection, and subsequently promotes the progression of HCC.

Overexpression of TIP30 inhibits the growth and invasion of glioma cells

Glioma is an aggressive malignancy with limited effective treatment and poor prognosis. Therefore, the identification of novel prognostic markers and effective therapeutic targets is important for the treatment of human glioma. TIP30 is a tumor suppressor involved in the regulation of numerous cellular processes, including tumor cell growth, metastasis, and angiogenesis in various human cancers. The present study investigated whether Tat-interacting protein (TIP)30 was able to regulate tumorigenesis and predict the clinical outcome of patients with glioma. A total of 92 human glioma tissue samples and 10 normal brain tissue samples were examined by immunostaining. The results indicated that the expression levels of TIP30 significantly decreased in glioma tissue samples. as compared with normal brain tissue samples. Furthermore, TIP30 expression was inversely correlated with tumor histological classification, pathological grade, tumor size, and epidermal growth factor receptor (EGFR) expression; however, no association was detected between TIP30 expression and patient age and gender. In addition, patients with positive TIP30 expression exhibited significantly longer median overall survival rates, as compared with those with negative TIP30 expression. In vitro experiments revealed that upregulation of TIP30 expression by lentiviral vector transfection inhibited cell growth and induced cell apoptosis, as determined by MTT assay and Annexin V-fluorescein isothiocyanate staining, respectively. In addition, TIP30 expression markedly attenuated cell migration and invasion, as determined by wound healing and transwell assays. Upregulation of TIP30 expression in glioma cells decreased the expression levels of EGFR and its associated downstream molecules phosphorylated extracellular signal-regulated kinases (ERK) and phosphorylated AKT, as determined by western blot analysis. The results of the present study indicated that TIP30 may suppress oncogenesis and glioma progression, thereby improving the prognosis of patients with glioma. Therefore, TIP30 may prove useful as a prognostic biomarker, and as a potential target for glioma therapy.

Long non-coding RNA growth arrest-specific transcript 5 in tumor biology

The recognition of the biological relevance of long non-coding RNA (lncRNA) molecules has only recently been recognized as one of the most significant advances in contemporary molecular biology. A growing body of evidence indicates that lncRNAs act not only as the intermediary between DNA and protein but also as significant protagonists of cellular functions. The dysregulation of lncRNAs has increasingly been linked to numerous human diseases, particularly cancers. Recent studies have demonstrated that the lncRNA growth arrest-specific transcript 5 (GAS5) was pervasively downexpressed in most human cancers compared with non-cancerous adjacent tissues including gastric, breast, lung and prostate cancer. In addition, patients with decreased GAS5 expression have a significantly poorer prognosis than those with higher expression. Furthermore, GAS5 is involved in the control of cell apoptosis, proliferation, metastasis, angiogenesis, DNA repair and tumor cell metabolism. This review provides an overview of the current knowledge concerning the role of GAS5 in tumor expression and biology function.

Reduction of TIP30 in esophageal squamous cell carcinoma cells involves promoter methylation and microRNA-10b

TIP30 is a putative tumor suppressor that can promote apoptosis and inhibit angiogenesis. However, the role of TIP30 in esophageal squamous cell carcinoma (ESCC) biology has not been investigated. Immunohistochemistry was used to investigate the expression of TIP30 in 70 ESCC. Hypermethylation of TIP30 was evaluated by the methylation specific PCR (MSP) method in ESCC (tumor and paired adjacent non-tumor tissues). Lost expression of TIP30 was observed in 50 of 70 (71.4%) ESCC. 61.4% (43 of 70) of primary tumors analyzed displayed TIP30 hypermethylation, indicating that this aberrant characteristic is common in ESCC. Moreover, a statistically significant inverse association was found between TIP30 methylation status and expression of the TIP30 protein in tumor tissues (p=0.001). We also found that microRNA-10b (miR-10b) targets a homologous DNA region in the 3'untranslated region of the TIP30 gene and represses its expression at the transcriptional level. Reporter assay with 3'UTR of TIP30 cloned downstream of the luciferase gene showed reduced luciferase activity in the presence of miR-10b, providing strong evidence that miR-10b is a direct regulator of TIP30. These results suggest that TIP30 expression is regulated by promoter methylation and miR-10b in ESCC.

Decreased TIP30 promotes Snail-mediated epithelial-mesenchymal transition and tumor-initiating properties in hepatocellular carcinoma

The poor prognosis of hepatocellular carcinoma (HCC) is mainly due to tumor recurrence and metastases. Recently, epithelial-mesenchymal transition (EMT) has been implicated in tumor invasion and metastasis. However, the underlying molecular mechanisms are yet to be elucidated. Here, we show that 30-kDa Tat-interacting protein (TIP30), also called CC3, is significantly downregulated during transforming growth factor-β-induced EMT. In our in vitro and in vivo studies, we show that decreased TIP30 expression leads to EMT, as well as enhanced motility and invasion of HCC cells. Also, increased self-renewal ability and chemotherapeutic resistance are observed with TIP30 depletion. Moreover, Snail is one of the key transcription factors promoting EMT, and overexpression of TIP30 greatly decreased nucleic accumulation in Snail through the regulation of intracellular localization. Small interfering RNAs targeting Snail attenuated EMT and tumor-initiating properties induced by TIP30 deficiency. We further confirmed that TIP30 competitively interrupted the interaction of Snail with importin-β2 to block the nuclear import of Snail. Consistently, TIP30 expression significantly correlates with E-cadherin expression in HCC patients. TIP30 or combination of E-cadherin is a powerful marker in predicting the prognosis of HCC. Taken together, our results suggest a novel and critical role of TIP30 involved in HCC progression and aggressiveness.

Decreased TIP30 expression predicts poor prognosis in pancreatic cancer patients

Pancreatic ductal adenocarcinoma (PDAC) is known for its aggressive growth, and is characterized by early tissue invasion and metastasis with poor prognosis. Identifying prognostic markers and delineating the underlying mechanisms that promote progression of PDAC are important for the treatment of pancreatic cancer. TIP30, a newly identified tumor suppressor, appears to be involved in multiple processes during tumor development and metastasis. Here, we investigated the expression of TIP30 in PDAC and its prognostic value in PDAC patients. We examined the expression of TIP30 by immunohistochemistry in tissue microarrays containing 106 surgically resected PDAC. Kaplan-Meier analysis and Cox proportional hazards regression modeling analysis showed that TIP30 expression independently predicted better survival in pancreatectomy patients (p < 0.01). Moreover, decreased TIP30 expression was associated with lymph node metastasis (p < 0.05) and loss of E-cadherin expression (r = 0.329, p < 0.01). Suppression of TIP30 resulted in upregulation of Snail and subsequent downregulation of E-cadherin in SW1990 cells containing high-level of endogenous TIP30. However, in the PANC-1 cells containing low level of endogenous TIP30, suppressing TIP30 caused upregulation of Slug instead of Snail, followed by upregulation of MMP9 rather than E-cadherin. Taken together, our work reveals that decreased TIP30 expression is able to enhance invasion and metastasis of pancreatic cancer cells through upregulation of the Snail family members and may serve as an independent predictor for poor outcomes in PDAC patients.

IL28B genotype and the expression of ISGs in normal liver

BACKGROUND & AIMS

Both polymorphisms in the IL28B gene locus and ISG expression levels are associated with the outcome of hepatitis C virus (HCV) infection. The two are also interrelated, although the mechanism is unknown. Favourable CC genotype at rs12979860 expresses lower baseline ISG levels and responds better to treatment than unfavourable CT and TT genotypes. Little is known about this relationship in normal, uninfected liver. This study sought to explore this relationship.

METHODS

Normal human liver specimens (64) and HCV positive human liver specimens (95) were genotyped for IL28B rs12979860 C > T. mRNA levels of ISGs and other relevant genes were studied by qPCR.

RESULTS

Most studied ISGs had significantly different expression by IL28B genotype in normal liver. CC genotype expressed the highest levels, CT intermediate and TT the lowest. This is opposite to the pattern seen in HCV patients. Principal component analysis of IL28B genotype and ISG expression further revealed a distinct set of genes correlated with the C allele (ISG15, HTATIP2, LGALS3BP, IRF2 and BCL2) and T allele (IFNα, β, γ, λ3 and CD80).

CONCLUSION

A subset of ISGs was found to be differentially expressed in normal liver by IL28B genotype. This suggests a relationship between IL28B genotype and gene expression before HCV infection.

The association of osteopontin and LMX1A expression with World Health Organization grade in meningiomas and gliomas

AIMS

Osteopontin (OPN) and LIM homeobox transcription factor 1, alpha (LMX1A) are important factors related to tumour progression, invasion and metastasis in human cancers. The aim of this study was to test the hypothesis that expression of OPN and of LMX1A correlate with the World Health Organization (WHO) grading system of primary brain tumours.

METHODS AND RESULTS

Immunohistochemical analyses of OPN and LMX1A expression were performed in 139 cases of brain tumour, including 65 meningiomas, 71 gliomas, and three central neurocytomas. More than 90% of WHO grade I meningiomas showed negative or weak staining for OPN and LMX1A. However, among all WHO grade II and III meningiomas, 100% and 66.7% showed moderate or strong staining for OPN and LMX1A, respectively. Similarly, higher percentages of WHO grade I and II gliomas than of WHO grade III and IV gliomas showed negative or weak staining for OPN. A higher intensity of immunoreactivity for LMX1A correlated with more advanced grade in WHO grade I-III gliomas, but not in WHO grade IV tumours.

CONCLUSIONS

Higher immunostaining intensity for OPN and LMX1A correlated with WHO grades for meningiomas and some gliomas. Contrary to our expectations, LMX1A staining in WHO grade IV gliomas was shown to be weaker than in WHO grade III tumours.

TIP30 loss enhances cytoplasmic and nuclear EGFR signaling and promotes lung adenocarcinogenesis in mice

Lung adenocarcinoma, the most common type of human non-small cell lung cancer (NSCLC), frequently overexpresses EGFR. However, the mechanisms underlying EGFR overexpression are not completely understood. Recent studies have identified that decreased expression of TIP30 is associated with the metastasis of human NSCLCs, but a causative relationship between TIP30 deficiency and NSCLC development remains unclear. We show here that Tip30 deletion leads to spontaneous development of lung adenomas and adenocarcinomas in mice. Lung tumor development was preceded by aberrant expansion of bronchioalveolar stem/progenitor and alveolar type II cells, as well as increased expression of EGFR and its downstream signaling factors in the lung of Tip30^−/− mice. Moreover, TIP30 knockdown in human lung adenocarcinoma cells resulted in prolonged EGFR activity in early endosomes, delayed EGFR degradation, increased EGFR nuclear localization, leading to up-regulated pAKT and pERK1/2 expression. Importantly, in human lung adenocarcinomas, low TIP30 expression correlates with prolonged patient overall and post-progression survival times. Together, these results suggest that TIP30 functions as a tumor suppressor to inhibit EGFR cytoplasmic and nuclear signaling and suppress adenocarcinogenesis in the lung and highlight the potential of therapeutic strategies aiming at inhibiting EGFR signaling for patients with low TIP30 expression lung adenocarcinoma.

Hypermethylation-mediated reduction of LMX1A expression in gastric cancer

LMX1A is epigenetically inactivated in cervical cancer. However, the expression and methylation status of LMX1A in gastric cancer tissues remains unknown. In the present study, we found that the expression of LMX1A was significantly decreased in gastric cancer tissues compared with normal tissues. A statistically significant inverse association was found between the LMX1A methylation status and expression of LMX1A in tumor tissues (P = 0.008). Restoration of LMX1A induced cell apoptosis and suppressed anchorage-independent growth, suggesting LMX1A may be a potential biomarker for gastric cancer.

CC3/TIP30 affects DNA damage repair

Background

The pro-apoptotic protein CC3/TIP30 has an unusual cellular function as an inhibitor of nucleocytoplasmic transport. This function is likely to be activated under conditions of stress. A number of studies support the notion that CC3 acts as a tumor and metastasis suppressor in various types of cancer. The yeast homolog of CC3 is likely to be involved in responses to DNA damage. Here we examined the potential role of CC3 in regulation of cellular responses to genotoxic stress.

Results

We found that forced expression of CC3 in CC3-negative cells strongly delays the repair of UV-induced DNA damage. Exogenously introduced CC3 negatively affects expression levels of DDB2/XPE and p21CIP1, and inhibits induction of c-FOS after UV exposure. In addition, exogenous CC3 prevents the nuclear accumulation of P21CIP in response to UV. These changes in the levels/localization of relevant proteins resulting from the enforced expression of CC3 are likely to contribute to the observed delay in DNA damage repair. Silencing of CC3 in CC3-positive cells has a modest delaying effect on repair of the UV induced damage, but has a much more significant negative affect on the translesion DNA synthesis after UV exposure. This could be related to the higher expression levels and increased nuclear localization of p21CIP1 in cells where expression of CC3 is silenced. Expression of CC3 also inhibits repair of oxidative DNA damage and leads to a decrease in levels of nucleoredoxin, that could contribute to the reduced viability of CC3 expressing cells after oxidative insult.

Conclusions

Manipulation of the cellular levels of CC3 alters expression levels and/or subcellular localization of proteins that exhibit nucleocytoplasmic shuttling. This results in altered responses to genotoxic stress and adversely affects DNA damage repair by affecting the recruitment of adequate amounts of required proteins to proper cellular compartments. Excess of cellular CC3 has a significant negative effect on DNA repair after UV and oxidant exposure, while silencing of endogenous CC3 slightly delays repair of UV-induced damage.