Overexpression of axin downregulates TCF-4 and inhibits the development of lung cancer

Triad1 Promotes the Inflammatory Response and Neuronal Apoptosis to Aggravate Acute Spinal Cord Injury in Rats

Objective

Spinal cord injury (SCI) is one of the most devastating central injuries, resulting in serious locomotor deficits. Triad1 is known to play an important role in SCI, but its effects on the inflammatory response and physiological behavior have not been thoroughly studied. This study is aimed at examining the effects of Triad1 on the inflammatory response and neuronal injury in acute SCI in rats.

Methods

Twenty-four male Sprague–Dawley (SD) rats were randomly divided into a control group, SCI group, sh-NC group, and Triad1 knockout group (sh-Triad1). The Basso Beattie Bresnahan locomotor rating scale was utilized for the assessment of the motor ability of rats. Hematoxylin and eosin (H&E), Luxol fast blue (LFB), and TUNEL staining were used to assess the pathological injury, demyelination, and neuronal apoptosis, respectively. ELISA was used to detect the levels of IL-1β, IL-10, and TNF-α, and qRT-PCR was used to examine the expression level of Triad1. Furthermore, the protein levels of Triad1, Bax, Bcl-2, and cleaved caspase-3 were determined using western blotting.

Results

The Triad1 expression level was upregulated in damaged spinal cord tissue. Knockdown of Triad1 improved motor function and reduced SCI as well as apoptosis of spinal cord neurons. In addition, the knockdown of Triad1 inhibited the inflammatory response caused by SCI.

Conclusion

Knockdown of Triad1 can reduce SCI in rats with acute SCI by inhibiting the inflammatory response and apoptosis.

Single-cell RNA sequencing reveals spatiotemporal heterogeneity and malignant progression in pancreatic neuroendocrine tumor

Aims: Using Single-cell RNA sequencing (scRNA-seq), we explored the spatiotemporal heterogeneity of pancreatic neuroendocrine tumors (pNETs) and the underlying mechanism for malignant progression.

Methods: scRNA-seq was conducted on three tumor tissues (two primary tissues from different sites, one liver metastatic lesion), one normal liver tissue, and peripheral blood mononuclear cells from one patient with a metastatic G2 pNET, followed by bioinformatics analysis and validation in a pNETs cohort.

Results: The transcriptome data of 24.544 cells were obtained. We identified subpopulations of functional heterogeneity within malignant cells, immune cells, and fibroblasts. There were intra- and inter-heterogeneities of cell subpopulations for malignant cells, macrophages, T cells, and fibroblasts among all tumor sites. Cell trajectory analysis revealed several hallmarks of carcinogenesis, including the hypoxia pathway, metabolism reprogramming, and aggressive proliferation, which were activated at different stages of tumor progression. Evolutionary analysis based on mitochondrial mutations defined two dominant clones with metastatic capacity. Finally, we developed a gene signature (PCSK1 and SMOC1) defining the metastatic potential of the tumor and its prognostic value was validated in a cohort of thirty G1/G2 patients underwent surgical resection.

Conclusions: Our scRNA-seq analysis revealed intra- and intertumor heterogeneities in cell populations, transcriptional states, and intercellular communications among primary and metastatic lesions of pNETs. The single-cell level characterization of the spatiotemporal dynamics of malignant cell progression provided new insights into the search for potential novel prognostic biomarkers of pNETs.

APC and AXIN2 Are Promising Biomarker Candidates for the Early Detection of Adenomas and Hyperplastic Polyps

Aberrant activation of the WNT/CTNNB1 pathway is notorious in colorectal cancer (CRC). Here, we demonstrate that the expression of specific and crucial WNT signaling pathway genes is linked to disease progression in colonic adenomatous (AP) and hyperplastic (HP) polyps in an Iranian patient population. Thus, we highlight potential gene expression profiles as candidate novel biomarkers for the early detection of CRC. From a 12-month study (2016-2017), 44 biopsy samples were collected during colonoscopy from the patients with colorectal polyps and 10 healthy subjects for normalization. Clinical and demographic data were collected in all cases, and mRNA expression of APC, CTNNB1, CDH1, AXIN1, and AXIN2 genes was investigated using real-time polymerase chain reaction (PCR). CTNNB1 and CDH1 expression levels were unaltered in AP and HP subjects, whereas mRNA expression of APC was decreased in AP contrasted with HP subjects, with a significant association between APC downregulation and polyp size. Although AXIN1 showed no changes between AP and HP groups, a significant association between AXIN1 and dysplasia grade was found. Also, significant upregulation of AXIN2 in both AP and HP subjects was detected. In summary, we have shown increased expression of AXIN2 and decreased expression of APC correlating with grade of dysplasia and polyp size. Hence, AXIN2 and APC should be explored as biomarker candidates for early detection of AP and HP polyps in CRC.

TCF-4 Regulated lncRNA-XIST Promotes M2 Polarization Of Macrophages And Is Associated With Lung Cancer

Background

Little is known about the biological function of long non-coding RNA X inactive specific transcript (lncRNA XIST) and its underlying mechanism in tumor-associated macrophage (TAM) polarization of lung cancer.

Materials and methods

The expression of lncRNA XIST in macrophages was detected by RT-qPCR. The function of lncRNA XIST on IL-4-induced M2 polarization was evaluated by transfection of shRNA and RT-qPCR or Western blotting detection of M2 specific markers. Contact between T-cell-specific transcription factor 4 (TCF-4) and lncRNA XIST was verified by bioinformatics and luciferase assay. The relation between lncRNA XIST and lung cancer was determined by bioinformatics.

Results

The expression of lncRNA XIST in THP-1-differentiated macrophages was significantly increased in M2 macrophages than M1 (P < 0.05). lncRNA XIST downregulation suppressed the IL-4-induced M2 polarization, inducing downregulation of M2 specific markers such as IL-10, Arg-1, and CD163. However, the suppression was aborted by overexpression of TCF-4. Mechanistically, lncRNA XIST was regulated by TCF-4 through direct binding. Additionally, lung cancer conditioned macrophages exhibited high expression of lncRNA XIST and lung cancer tissues highly expressed TCF-4, indicating TCF-4 regulated lncRNA XIST closely correlated with macrophage polarization and tumor progression of lung cancer.

Conclusion

Taken together, this study demonstrated the important role of TCF-4 regulated lncRNA XIST in regulating M2 polarization and gave a novel insight into the TAMs regulation and potential therapeutic target of lung cancer.

Roles of β-catenin, TCF-4, and survivin in nasopharyngeal carcinoma: correlation with clinicopathological features and prognostic significance

Background

Nasopharyngeal carcinoma (NPC) is a common malignant tumor of the head and neck region with poorly understood progression and prognosis. The present study aims at exploring whether the expression of β-catenin, TCF-4, and survivin affects clinicopathological features and prognostic significance in NPC.

Methods

We enrolled 164 patients with NPC and 70 patients with chronic nasopharyngitis (CNP) in this study. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC) were conducted to evaluate the expression of β-catenin, TCF-4, and survivin. Spearman’s rank correlation analysis and Pearson correlation analysis were used to measure the correlation of β-catenin, TCF-4, and survivin. Risk factors for prognosis and survival conditions of NPC patients were analyzed by Cox proportional hazards model and Kaplan–Meier curves.

Results

The results obtained revealed that mRNA and protein expression of β-catenin, TCF-4, and survivin was higher in NPC tissues than in CNP tissues. Positive correlations amongst β-catenin, TCF-4, and survivin were identified by Spearman’s rank correlation analysis and Pearson correlation analysis. There was a significant correlation in expression of β-catenin, TCF-4, and survivin with EBV DNA, EBV-VCA-IgA, EBV-EA-IgA, T stage, N stage, and clinicopathological stages. Lower overall survival (OS), distant metastasis-free survival (DMFS), local recurrence-free survival (LRFS), and disease-free survival (DFS) rates were detected in NPC patients with positive expression of β-catenin, TCF-4, and survivin, in contrast to those with negative expression. Cox proportional hazards model demonstrated that β-catenin, TCF-4, and survivin protein positive expression were independent risk factors for OS and DFS of NPC prognosis; there was an evident correlation between clinicopathological stages, TCF-4, and EBV-EA-IgA and OS, DMFS, LRFS, and DFS of NPC.

Conclusions

The aforementioned results indicate that β-catenin, TCF-4, and survivin proteins are highly expressed in NPC, which can be used as factors to predict the malignancy of NPC. In addition, positive expression of β-catenin, TCF-4, and survivin are potential risk factors that lead to an unfavorable prognosis of OS and DFS in NPC patients.

A serine in exon 11 determines the full transcriptional activity of TCF-4 in lung carcinoma cells

Activation of T cell factor-4 (TCF-4) is causally linked to the development of lung carcinoma, while the mechanism of sequence-dependent TCF-4 activity is still obscure. Using reverse transcription-polymerase chain reaction (RT-PCR), here, we demonstrated that sequences of exon 11 in TCF-4 were present in lung carcinoma cells but not in normal lung epithelial cells. Loss of exon 11 in TCF-4 inhibited TCF-4-induced cell growth of lung carcinoma and prolonged the survival time of Lewis lung carcinoma (LLC) tumor-bearing mice. Mechanistically, loss of exon 11 in TCF-4 attenuated the binding activity between TCF-4 protein and its canonical binding site, inhibited TOP/FOP luciferase activity and suppressed mRNA expression of Wnt signaling targets. By performing truncated and site-directed mutations, we further demonstrated that the 16th amino acid serine in exon 11 was responsible for TCF-4-mediated Wnt signaling. In vivo experiments indicated that a mutation of the 16th amino acid serine in exon 11 of TCF-4 could mimic the anti-tumor effect of Wnt signaling inhibitor. Taken together, we identified a serine determining the transcriptional activity of TCF-4 in lung carcinoma cells, and sequencing of TCF-4 mRNA might be an effective strategy to evaluate the Wnt pathway activation and prognosis in lung cancer.

RIF1 promotes tumor growth and cancer stem cell-like traits in NSCLC by protein phosphatase 1-mediated activation of Wnt/β-catenin signaling

Wnt/β-catenin signaling is essential for proliferation and maintenance of cancer stem cell-like traits of various cancer cells. In non-small-cell lung carcinoma (NSCLC), the mechanisms underlying the hyperactivation of Wnt signaling remain unclear, as mutations in APC and β-catenin genes are rare in NSCLC. RIF1 has been shown upregulated in breast and cervical cancer, this study intends to find out the potential effects of the expression and biological functions of RIF1 in NSCLC. Here we revealed that RIF1 was highly expressed in NCSLC at both mRNA and protein levels. RIF1 expression was significantly associated with clinical stage (P < 0.05) and prognosis (P < 0.001) of NSCLC patients. RIF1 knockdown inhibited NSCLC cell growth in vitro and in vivo, whereas overexpression of RIF1 in NSCLC cell lines promoted cell growth, cell cycle progression and cancer stem cell (CSC)-like properties via promoting PP1-AXIN interaction and thereby activating Wnt/β-catenin signaling. Inhibition of PP1 in RIF1-overexpressed cells counteracted the effects of RIF1 on cell growth and CSC-like phenotype, as well as the Wnt/β-catenin signaling. RIF1 expression was positively correlated with β-catenin at the protein level in 32 NSCLC tissues. RIF1 expression closely related to MYC (r = 0.28, P < 0.001) and CCND1 (r = 0.14, P < 0.01) expression at the mRNA level in cohorts of The Cancer Genome Atlas (TCGA). These results indicated that RIF1 had an oncogenic role as a novel positive regulator of Wnt/β-catenin signaling by directing PP1 to dephosphorylate AXIN; this novel mechanism may present a new therapeutic target for NSCLC.

The molecular biology of lung cancer brain metastasis: an overview of current comprehensions and future perspectives

Brain metastases occur in 20-40% of patients with advanced malignancies and lung cancer is one of the most common causes of brain metastases. The occurrence of brain metastases is associated with poor prognosis and high morbidity in patients with advanced lung cancer, even after intensive multimodal therapy. Progress in treating brain metastases has been hampered by a lack of model systems, a lack of human tissue samples, and the exclusion of brain metastatic patients from many clinical trials. While the biology of brain metastasis is still poorly understood, it is encouraging to see more efforts are beginning to be directed toward the study of brain metastasis. During the multi-step process of metastasis, functional significance of gene expressions, changes in brain vasculature, abnormal secretion of soluble factors and activation of autocrine/paracrine signaling are considered to contribute to the brain metastasis development. A better understanding of the mechanism of this disease will help us to identify the appropriate therapeutic strategies, which leads to circumvent brain metastases. Recent findings on the biology of lung cancer brain metastases and translational leads identified by molecular studies are discussed in this review.

Signaling Pathways in Thyroid Cancer and Their Therapeutic Implications

Thyroid cancer is a common malignancy of endocrine system, and has now become the fastest increasing cancer among all the malignancies. The development, progression, invasion, and metastasis are closely associated with multiple signaling pathways and the functions of related molecules, such as Src, Janus kinase (JAK)-signal transducers and activators of transcription (STAT), mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K)/Akt, NF-κB, thyroid stimulating hormone receptor (TSHR), Wnt-β-catenin and Notch signaling pathways. Each of the signaling pathways could exert its function singly or through network with other pathways. These pathways could cooperate, promote, antagonize, or interact with each other to form a complex network for the regulation. Dysfunction of this network could increase the development, progression, invasion, and metastasis of thyroid cancer. Inoperable thyroid cancer still has a poor prognosis. However, signaling pathway-related targeted therapies offer the hope of longer quality of meaningful life for this small group of patients. Signaling pathway-related targets provide unprecedented opportunities for further research and clinical development of novel treatment strategies for this cancer. In the present work, the advances in these signaling pathways and targeted treatments of thyroid cancer were reviewed.

Wnt signaling pathway pharmacogenetics in non-small cell lung cancer

Wnt/β-catenin pathway alterations in non-small cell lung cancer (NSCLC) are associated with poor prognosis and resistance. In 598 stage III-IV NSCLC patients receiving platinum-based chemotherapy at MD Anderson Cancer Center (MDACC), we correlated survival with 441 host SNPs in 50 Wnt pathway genes. We then assessed the most significant SNPs in 240 Mayo Clinic patients receiving platinum-based chemotherapy for advanced NSCLC, 127 MDACC patients receiving platinum-based adjuvant chemotherapy and 340 early stage MDACC patients undergoing surgery alone (cohorts 2–4). In multivariate analysis, survival correlates with SNPs for AXIN2 (rs11868547 and rs4541111, of which rs11868547 was assessed in cohorts 2–4), Wnt-5B (rs12819505), CXXC4 (rs4413407) and WIF-1 (rs10878232). Median survival was 19.7, 15.6, and 10.7 months for patients with 1, 2, and 3–5 unfavorable genotypes, respectively (p= 3.8×10⁻⁹). Survival tree analysis classified patients into two groups (MST 11.3 vs 17.3 months, p=4.7×10⁻⁸). None of the SNPs achieved significance in cohorts 2–4; however, there was a trend in the same direction as cohort 1 for 3 of the SNPs. Using online databases, we found rs10878232 displayed expression quantitative trait loci (eQTL) correlation with the expression of LEMD3, a neighboring gene previously associated with NSCLC survival. In conclusion, results from cohort 1 provide further evidence for an important role for Wnt in NSCLC. Investigation of Wnt inhibitors in advanced NSCLC would be reasonable. Lack of a SNP association with outcome in cohorts 2–4 could be due to low statistical power, impact of patient heterogeneity, or false positive observations in cohort 1.

Overexpression of RNF146 in non-small cell lung cancer enhances proliferation and invasion of tumors through the Wnt/β-catenin signaling pathway

Studies have suggested a possible correlation between the newly identified E3 ubiquitin ligase ring finger protein 146 (RNF146) and tumor development. However, until now, studies on RNF146 have been restricted to poly(ADP-ribosyl)ation and ubiquitin ligation, whereas the role of RNF146 in tumor biology has rarely been reported. In the present study, the role of RNF146 in non-small cell lung cancer (NSCLC) was investigated. The results showed that the expression of RNF146 was increased in clinical lung cancer samples and cell lines. RNF146 expression correlated with tumor size, differentiation level, lymphatic metastasis, pTNM staging, and prognosis of patients in stage I. RNF146 expression was negatively correlated with Axin expression but positively correlated with the nuclear expression of β-catenin in NSCLC tissues. RNF146 downregulated the expression of Axin in lung cancer cell lines and induced the expression and nuclear distribution of β-catenin. Overexpression of RNF146 in NSCLC cell lines increased the levels of cyclinD1, cyclinE, and CDK4, promoted cell cycle G0/G1-S transitions, and regulated cell proliferation. Overexpression of RNF146 led to upregulated levels of matrix metalloproteinases 2 and 7 and enhanced lung cancer cell invasiveness, events that were mediated by the classical Wnt/β-catenin signaling pathway. In summary, the data in the present study indicate that RNF146 regulated the development and progression of NSCLC by enhancing cell growth, invasion, and survival, suggesting that RNF146 may be a potential treatment target in NSCLC.

Colorectal cancer: molecular mutations and polymorphisms

Colorectal cancer (CRC) is one of the major causes of mortality and morbidity, and is the third most common cancer in men and the second most common cancer in women worldwide. The incidence of CRC shows considerable variation among racially or ethnically defined populations in multiracial/ethnic countries. The tumorigenesis of CRC is either because of the chromosomal instability (CIN) or microsatellite instability (MIN) or involving various proto-oncogenes, tumor-suppressor genes, and also epigenetic changes in the DNA. In this review I have focused on the mutations and polymorphisms of various important genes of the CIN and MIN pathways which have been implicated in the development of CRC.

Abnormal hypermethylation and clinicopathological significance of Axin gene in lung cancer

Axin is an important negative regulator of Wnt pathway. We have reported that reduced expression of Axin could be detected in lung cancer tissues, but the mechanism is not clear. By analyzing the genomic sequence, we note that Axin gene promoter is rich in CpGs. Little is known about the methylation status of Axin gene in lung cancer. So, nested MSP and RT-PCR were used to study the methylation status and mRNA expression of Axin gene in lung cancer tissues and cell lines. The results showed that hypermethylated Axin gene promoter and reduced mRNA expression level of Axin could be detected in lung cancer tissues but not in their paired autologous normal lung tissues (P < 0.01). The hypermethylated Axin gene promoter significantly correlated with the degree of differentiation (P = 0.03), lymph node metastasis (P = 0.048) and TNM classifications (P = 0.032). Demethylation reagent 5-aza-2-deoxycytidine significantly up-regulate Axin expression in BE1 cells (with hypermethylated Axin gene promoter) but not in H460 cells (with unmethylated Axin gene promoter). MTT (3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and transwell matrigel invasion assay showed that 5-aza-2-deoxycytidine treatment inhibited cell growth and invasion more significantly in BE1 cells than that in H460 cells. Our data indicate that hypermethylated Axin gene significantly correlates with the progression of lung cancer and might serve as a new target of clinical therapy for lung cancer patients in future.

[The research progress about Wnt pathway of lung cancer stem cells]

Being the most critical signaling molecule in the Wnt pathway, the Wnt/β-catenin signaling pathway plays an important role in the maintenance of the cell proliferation and clone formation of lung cancer stem cells. Since it is closely related to the WNT pathway, the proliferation of lung cancer stem cells can be restrained by blocking the WNT pathway or influencing its key protein. Such method provides a new method for the treatment of lung cancer. By summarizing the state of-the-art research of lung cancer stem cells and the Wnt pathway from 2005 to 2010, their relationship is investigated.

Novelty of Axin 2 and lack of Axin 1 gene mutation in colorectal cancer: a study in Kashmiri population

Colorectal cancer is (CRC) one of the leading causes of mortality and morbidity. Various genetic factors have been reported to be involved in the development of colorectal cancers including Axin gene. Axin, a major scaffold protein, plays an important role in various bio signaling pathways. We aim to study mutational pattern of Axin gene in colorectal cancer patients of Kashmiri population. The paired tumor and adjacent normal tissue specimens of 50 consecutive patients with CRC were used in our study. The DNA preparations were evaluated for the occurrence of Axin 1 and Axin 2 gene mutations by direct DNA sequencing. We analyzed exon 1a, 1b, 1c, 2, 4, 6, and 10 of Axin 1 and exon 7 of Axin 2. In this study, we found a novel mutation of G>T (GCT>TCT) transversion in exon 7 of Axin 2 gene at codon G695T (p.alanine > serine) at a frequency of 6% (3/50). In the same exon of Axin 2 gene a single nucleotide polymorphism (SNP) was detected in codon L688L (CCT>CTT) at a frequency of 36% (18/50). In exon 1c of Axin 1 a SNP was detected at codon D726D (GAT>GAC) at a frequency of 62.5% (31/50). Both the SNPs were synonymous hence do not lead to change of amino acid. Although Axin 1 and Axin 2 gene mutations have been found to be involved in the development of colorectal cancers, it seems to be a relatively rare event in Kashmiri population. However, an interesting finding of this study is the novelty of Axin 2 gene mutations which may be a predisposing factor in ethnic Kashmiri population to CRC.

Disabled-2 and Axin are concurrently colocalized and underexpressed in lung cancers

Disabled-2 expression is reduced in many cancers, suggesting that it is a potential tumor suppressor protein. To elucidate the role of Disabled-2 in lung cancer, we examined the expression of Disabled-2, the Disabled-2-binding protein Axin, and DNA methyltransferase-1 in lung cancer tissues and corresponding normal lung tissues using immunohistochemistry and Western blots. We also determined the subcellular localization of Axin and Disabled-2 in A549 cells using confocal immunofluorescence. Disabled-2 expression was significantly reduced in lung cancers and was colocalized and coexpressed with Axin (correlation coefficient = 0.321, P < .001 for cytoplasmic expression; correlation coefficient = 0.393, P < .001 for nuclear expression). Reduced nuclear Disabled-2 expression was correlated with the differentiation (P = .048) and TNM stage (P = .048) of the tumor. The cytoplasmic expression of Axin was also correlated with differentiation (P = .042), whereas the nuclear expression of Axin was correlated with both histologic type (P = .001) and TNM stage (P < .001) of lung cancers. Expression of DNA methyltransferase-1 was negatively correlated with the cytoplasmic expression of Axin (correlation coefficient = -0.244, P = .012) but positively correlated with the histologic type (P = .004), differentiation (P = .036), TNM stage (P = .044), and lymphatic metastasis (P = .011). Expressions of Disabled-2 and Axin were concurrently reduced and correlated with the malignant phenotype of lung cancers. Enhanced expression of DNA methyltransferase-1 correlated with the reduced expression of Axin and could be a marker for lung cancer development and progression.

A fork in the path: Developing therapeutic inroads with FoxO proteins

Advances in clinical care for disorders involving any system of the body necessitates novel therapeutic strategies that can focus upon the modulation of cellular proliferation, metabolism, inflammation and longevity. In this respect, members of the mammalian forkhead transcription factors of the O class (FoxOs) that include FoxO1, FoxO3, FoxO4 and FoxO6 are increasingly being recognized as exciting prospects for multiple disorders. These transcription factors govern development, proliferation, survival and longevity during multiple cellular environments that can involve oxidative stress. Furthermore, these transcription factors are closely integrated with several novel signal transduction pathways, such as erythropoietin and Wnt proteins, that may influence the ability of FoxOs to act as a “double-edge sword” to sometimes promote cell survival, but at other times lead to cell injury. Here we discuss the fascinating but complex role of FoxOs during cellular injury and oxidative stress, progenitor cell development, fertility, angiogenesis, cardiovascular function, cellular metabolism and diabetes, cell longevity, immune surveillance and cancer.

Quantification of beta-catenin signaling components in colon cancer cell lines, tissue sections, and microdissected tumor cells using reaction monitoring mass spectrometry

Reaction monitoring mass spectrometry has emerged as a powerful tool for targeted detection and quantification of proteins in clinical samples. Here, we report the use of gel electrophoresis for protein fractionation and liquid chromatography coupled to multiple reaction monitoring mass spectrometry (LC-MRM) screening for quantitative analysis of components from the Wnt/beta-catenin signaling pathway, which contributes to colon tumor formation and progression. In silico tools are used to design LC-MRM screens for each target protein. Following successful peptide detection, stable isotope labeled peptides are synthesized and developed as internal standards. Then, the assays are implemented in colon cancer cell lines to achieve detection in minimal amounts of cells, compatible with direct translation to clinical specimens. Selected assays are compared with qualitative results from immunoblotting (Westerns) and translated to individual frozen colon tissue sections and laser capture microdissected tumor cells. This LC-MRM platform has been translated from in vitro models to clinical specimens, forming the basis for future experiments in patient assessment.

Dishevelled-1 and dishevelled-3 affect cell invasion mainly through canonical and noncanonical Wnt pathway, respectively, and associate with poor prognosis in nonsmall cell lung cancer

Dishevelled (Dvl) family proteins are overexpressed in nonsmall cell lung cancer (NSCLC), but the correlation between Dvl overexpression and patient prognosis is not clear. The underlying mechanisms of Dvl-1 and Dvl-3 promoting lung cancer cell invasion require further research. We used immunohistochemistry to assess the presence of Dvl-1, Dvl-3, beta-catenin, and p120ctn, and compared their expression to the prognosis in 102 specimens from NSCLC patients. We also examined the effect of Dvl-1 and Dvl-3 on Tcf-dependent transcriptional activity, as well as on the invasiveness in A549 and LTEP-alpha-2 lung cancer cells. The results showed that Dvl-1 correlated to the abnormal expression of beta-catenin, while Dvl-3 correlated to p120ctn. Both Dvl-1 and Dvl-3 were related to the poor prognosis of patient. Dvl-1 overexpression enhanced the Tcf-dependent transcriptional activity and beta-catenin expression significantly. However, Dvl-3 had little effect on the Tcf-dependent transcriptional activity and beta-catenin expression, which was accompanied by p38 and JNK phosphorylation. Furthermore, the invasiveness of Dvl-3-enhanced cells was inhibited by p38 and JNK inhibitors. Exogenous expression of both Dvl-1 and Dvl-3 increased the p120ctn protein expression, while only Dvl-3 upregulated p120ctn mRNA. We conclude that both protein and mRNA of Dvl-1 and Dvl-3 are overexpressed in NSCLC in a manner related to poor prognosis. Dvl-1 may affect the biological behavior of lung cancer cells mainly through beta-catenin (canonical Wnt pathway), while Dvl-3 mainly through p38 and JNK pathway (noncanonical Wnt pathway).

Translational research in brain metastasis is identifying molecular pathways that may lead to the development of new therapeutic strategies

Central nervous system (CNS) or brain metastasis is an emerging area of interest in organ-specific metastasis research. Lung and breast cancers are the most common types of primary tumors to develop brain metastases. This disease complication contributes significantly to the morbidity and mortality of both of these common cancers; as such, brain metastasis is designated an unmet medical need by the US Food and Drug Administration (FDA). Recently, an increase in incidence of CNS disease has been noted in the literature for breast cancer, while it has been an ongoing major complication from lung cancer. Progress in treating brain metastases has been hampered by a lack of model systems, a lack of human tissue samples, and the exclusion of brain metastatic patients from many clinical trials. While each of those is significant, the major impediment to effectively treating brain metastatic disease is the blood-brain barrier (BBB). This barrier excludes most chemotherapeutics from the brain and creates a sanctuary site for metastatic tumors. Recent findings on the biology of this disease and translational leads identified by molecular studies are discussed in this article.

Wnt/beta-catenin signaling: a novel target for therapeutic intervention of fibrotic kidney disease

Fibrosis of epithelial parenchymal organs and end-stage organ failure, the final common pathway of many progressive chronic diseases including chronic kidney disease, continue to increase worldwide and are a major determinant of morbidity and mortality. Fibrosis is an active biosynthetic healing response initiated to protect the tissue from injury through the timed release of proteins but leads to serious tissue damage when it becomes independent from the initiating stimulus. Massive deposition of extracellular matrix by accumulation of myofibroblasts and disruption of the normal tissue architecture are characteristic of tissue fibrosis. The highly conserved Wnt/beta-catenin signaling pathway is essential to embryonic development in general and kidney morphogenesis in particular by regulating the expression of target genes, most often through the transcription factor T cell factor (TCF) and/or lymphoid enhancer factor (LEF). Emerging evidence from studies of renal fibrosis suggests that altered Wnt/beta-catenin signaling is linked to the pathogenesis of renal fibrosis. The renoprotective properties of some currently available drugs might be attributable in part to inhibition of Wnt signaling. The development of orally active Wnt modulators will provide a potentially important pharmacological tool for further investigating the role of Wnt/beta-catenin signaling and might offer a novel therapeutic strategy in renal fibrosis.

Axin downregulates TCF-4 transcription via beta-catenin, but not p53, and inhibits the proliferation and invasion of lung cancer cells

Background

We previously reported that overexpression of Axin downregulates T cell factor-4 (TCF-4) transcription. However, the mechanism(s) by which Axin downregulates the transcription and expression of TCF-4 is not clear. It has been reported that β-catenin promotes and p53 inhibits TCF-4 transcription, respectively. The aim of this study was to investigate whether β-catenin and/or p53 is required for Axin-mediated downregulation of TCF-4.

Results

Axin mutants that lack p53/HIPK2 and/or β-catenin binding domains were expressed in lung cancer cells, BE1 (mutant p53) and A549 (wild type p53). Expression of Axin or AxinΔp53 downregulates β-catenin and TCF-4, and knock-down of β-catenin upregulates TCF-4 in BE1 cells. However, expression of AxinΔβ-ca into BE1 cells did not downregulate TCF-4 expression. These results indicate that Axin downregulates TCF-4 transcription via β-catenin. Although overexpression of wild-type p53 also downregulates TCF-4 in BE1 cells, cotransfection of p53 and AxinΔβ-ca did not downregulate TCF-4 further. These results suggest that Axin does not promote p53-mediated downregulation of TCF-4. Axin, AxinΔp53, and AxinΔβ-ca all downregulated β-catenin and TCF-4 in A549 cells. Knock-down of p53 upregulated β-catenin and TCF-4, but cotransfection of AxinΔβ-ca and p53 siRNA resulted in downregulation of β-catenin and TCF-4. These results indicate that p53 is not required for Axin-mediated downregulation of TCF-4. Knock-down or inhibition of GSK-3β prevented Axin-mediated downregulation of TCF-4. Furthermore, expression of Axin and AxinΔp53, prevented the proliferative and invasive ability of BE1 and A549, expression of AxinΔβ-ca could only prevented the proliferative and invasive ability effectively.

Conclusions

Axin downregulates TCF-4 transcription via β-catenin and independently of p53. Axin may also inhibits the proliferation and invasion of lung cancer cells via β-catenin and p53.

Cytoplasmic Kaiso is associated with poor prognosis in non-small cell lung cancer

Background

Kaiso has been identified as a new member of the POZ-zinc finger family of transcription factors that are implicated in development and cancer. Although controversy still exists, Kaiso is supposed to be involved in human cancer. However, there is limited information regarding the clinical significance of cytoplasmic/nuclear Kaiso in human lung cancer.

Methods

In this study, immunohistochemical studies were performed on 20 cases of normal lung tissues and 294 cases of non-small cell lung cancer (NSCLC), including 50 cases of paired lymph node metastases and 88 cases with complete follow-up records. Three lung cancer cell lines showing primarily nuclear localization of Kaiso were selected to examine whether roles of Kaiso in cytoplasm and in nucleus are identical. Nuclear Kaiso was down-regulated by shRNA technology or addition a specific Kaiso antibody in these cell lines. The proliferative and invasive abilities were evaluated by MTT and Matrigel invasive assay, transcription of Kaiso's target gene matrilysin was detected by RT-PCR.

Results

Kaiso was primarily expressed in the cytoplasm of lung cancer tissues. Overall positive cytoplasmic expression rate was 63.61% (187/294). The positive cytoplasmic expression of Kaiso was higher in advanced TNM stages (III+IV) of NSCLC, compared to lower stages (I+II) (p = 0.019). A correlation between cytoplasmic Kaiso expression and lymph node metastasis was found (p = 0.003). In 50 paired cases, cytoplasmic expression of Kaiso was 78.0% (41/50) in primary sites and 90.0% (45/50) in lymph node metastases (p = 0.001). The lung cancer-related 5-year survival rate was significantly lower in patients who were cytoplasmic Kaiso-positive (22.22%), compared to those with cytoplasmic Kaiso-negative tumors (64.00%) (p = 0.005). Nuclear Kaiso staining was seen in occasional cases with only a 5.10% (15/294) positive rate and was not associated with any clinicopathological features of NSCLC. Furthermore, after the down-regulation of the nuclear expresses Kaiso in vitro, both proliferative and invasive abilities of three cancer cell lines were significantly enhanced, along with the up-regulation of Kaiso target gene, matrilysin.

Conclusion

Our data suggest cytoplasmic Kaiso expression is associated with poor prognosis of NSCLC and various subcellular localizations of Kaiso may play differential biological roles in NSCLC.

The "O" class: crafting clinical care with FoxO transcription factors

Forkhead Transcription Factors: Vital Elements in Biology and Medicine provides a unique platform for the presentation of novel work and new insights into the vital role that forkhead transcription factors play in both cellular physiology as well as clinical medicine. Internationally recognized investigators provide their insights and perspectives for a number of forkhead genes and proteins that may have the greatest impact for the development of new strategies for a broad array of disorders that can involve aging, cancer, cardiac function, neurovascular integrity, fertility, stem cell differentiation, cellular metabolism, and immune system regulation. Yet, the work clearly sets a precedent for the necessity to understand the cellular and molecular function of forkhead proteins since this family of transcription factors can limit as well as foster disease progression depending upon the cellular environment. With this in mind, our concluding chapter for Forkhead Transcription Factors: Vital Elements in Biology andMedicine offers to highlight both the diversity and complexity of the forkhead transcription family by focusing upon the mammalian forkhead transcription factors of the O class (FoxOs) that include FoxO1, FoxO3, FoxO4, and FoxO6. FoxO proteins are increasingly considered to represent unique cellular targets that can control numerous processes such as angiogenesis, cardiovascular development, vascular tone, oxidative stress, stem cell proliferation, fertility, and immune surveillance. Furthermore, FoxO transcription factors are exciting considerations for disorders such as cancer in light of their pro-apoptotic and inhibitory cell cycle effects as well as diabetes mellitus given the close association FoxOs hold with cellular metabolism. In addition, these transcription factors are closely integrated with several novel signal transduction pathways, such as erythropoietin and Wnt proteins, that may influence the ability of FoxOs to lead to cell survival or cell injury. Further understanding of both the function and intricate nature of the forkhead transcription factor family, and in particular the FoxO proteins, should allow selective regulation of cellular development or cellular demise for the generation of successful future clinical strategies and patient well-being.

Clever cancer strategies with FoxO transcription factors

Given that cancer and related disorders affect a wide spectrum of the world's population, and in most cases are progressive in nature, it is essential that future care must overcome the present limitations of existing therapies in the absence of toxic side effects. Mammalian forkhead transcription factors of the O class (FoxOs) may fill this niche since these proteins are increasingly considered to represent unique cellular targets directed against human cancer in light of their pro-apoptotic effects and ability to lead to cell cycle arrest. Yet, FoxOs also can significantly affect normal cell survival and longevity, requiring new treatments for neoplastic growth to modulate novel pathways that integrate cell proliferation, metabolism, inflammation and survival. In this respect, members of the FoxO family are extremely compelling to consider since these transcription factors have emerged as versatile proteins that can control angiogenesis, stem cell proliferation, cell adhesion and autoimmune disease. Further elucidation of FoxO protein function during neoplastic growth should continue to lay the foundation for the successful translation of these transcription factors into novel and robust clinical therapies for cancer.

Rogue proliferation versus restorative protection: where do we draw the line for Wnt and forkhead signaling?

BACKGROUND

Disease entities such as diabetes, neurodegeneration and cardiovascular disorders affect a significant portion of the world's population.

OBJECTIVE

Given that cellular survival and longevity in multiple disorders are tied to oxidative stress, apoptotic cell injury and immune system deregulation, the development of robust therapeutic strategies rests heavily upon the ability to balance each of these parameters.

METHODS

Here we discuss two exciting signaling pathways, namely Wnt and mammalian forkhead transcription factors predominantly of the O class superfamily, which can share integrated cytoprotective pathways during oxidative stress but may also adversely influence cellular survival and promote cancer cell proliferation.

CONCLUSION

Future investigations must elucidate the cellular determinants that govern the ability of Wnt and forkhead proteins to promote cellular longevity and possible disease remission but also allow for detrimental biological consequences and clinical compromise.

Current status and issues in cancer stem cell study

Cancer stem cells (CSCs) have been positively identified and successfully isolated from some but not all cancers. The studies on CSCs to date suggest that these cells are rare among the tumor cell population, and they are capable of self-renewing and maintaining tumor growth and heterogeneity. Therapies aimed at CSCs have shown some promise, but their further development will require a more thorough understanding of the biology of CSCs and methods for identifying and isolating this cell subpopulation. This review examines what is known to date regarding the similarities and differences between cancer and somatic stem cells: CSC surface marker development and cell isolation (including a model isolation from our lab), the frequency, potential origin, and signal transduction of CSCs, and the current state of CSC-targeting therapeutic strategies.

Dishevelled family proteins are expressed in non-small cell lung cancer and function differentially on tumor progression

BACKGROUND

Dishevelled (Dvl) family proteins are cytoplasmic mediators of the Wnt/beta-catenin signaling pathway and have recently been linked to cancers. However, the roles of individual Dvls and their expression in human cancers are poorly defined. This work aimed to characterize the expression of Dvls and their correlation to clinicopathological factors and beta-catenin expression in non-small cell lung cancer (NSCLC).

METHODS

We used immunohistochemistry to assess the presence of the three Dvl family proteins in 113 individual NSCLC specimens. Thirty-nine of the 113 cases were examined further for Dvl and beta-catenin protein expression in matched primary growths and autologous nodal metastases. We also examined the effect of Dvl-1 and Dvl-3 overexpression on beta-catenin expression and the invasive ability of A549 and QG56 lung cancer cells.

RESULTS

The positive expression rate in primary tumors was 53.1% (60/113) for total Dvl, 36.3% (41/113) for Dvl-1, 36.3% (41/113) for Dvl-2 and 41.6% (47/113) for Dvl-3, while normal adult bronchial and alveolar epithelia showed negative expression of all these proteins. The expression levels of all three Dvl proteins were significantly higher in adenocarcinomas than in squamous carcinomas, and were associated with poor tumor differentiation. The positive expression of Dvl-1 and Dvl-2 proteins was correlated to advanced pTNM stages (III-IV vs. I-II). In addition, the expression levels of Dvl-1 and Dvl-3 were significantly higher in nodal metastases than in primary growths, with the Dvl-1 expression correlating to beta-catenin expression in the metastases. Exogenous expression of Dvl-1 and Dvl-3 both enhanced the invasive ability of A549 and QG56 cells, but had differential effects on beta-catenin protein expression in either cell line, without influencing beta-catenin mRNA levels.

CONCLUSIONS

Expression of Dvl family proteins, Dvl-1, Dvl-2 and Dvl-3, is common in NSCLCs. They may contribute to the progression of NSCLCs, but Dvl-1 and Dvl-3 may function on this process through different signaling pathways.

The Wnt signaling pathway: aging gracefully as a protectionist?

No longer considered to be exclusive to cellular developmental pathways, the Wnt family of secreted cysteine-rich glycosylated proteins has emerged as versatile targets for a variety of conditions that involve cardiovascular disease, aging, cancer, diabetes, neurodegeneration, and inflammation. In particular, modulation of Wnt signaling may fill a critical void for the treatment of disorders that impact upon both cellular survival and cellular longevity. Yet, in some scenarios, Wnt signaling can become the catalyst for disease development or promote cell senescence that can compromise clinical utility. This double edge sword in regards to the role of Wnt and its signaling pathways highlights the critical need to further elucidate the cellular mechanisms governed by Wnt in conjunction with the development of robust pharmacological ligands that may open new avenues for disease treatment. Here we discuss the influence of the Wnt pathway during cell survival, metabolism, and aging in order for one to gain a greater insight for the novel role of Wnt signaling as well as exemplify its unique cellular pathways that influence both normal physiology and disease.