DIXDC1 increases the invasion and migration ability of non-small-cell lung cancer cells via the PI3K-AKT/AP-1 pathway

Molecular characterization of MET fusions from a large real-world Chinese population: A multicenter study

PURPOSE

MET is a notable driver gene in the diversity of aberrations with clinical relevance, including exon 14 skipping, copy number gain, point mutations, and gene fusions. Compared with the former two, MET fusions are severely under-reported, leaving a series of unanswered questions. In this study, we addressed this gap by characterizing MET fusions in a large, real-world Chinese cancer population.

METHODS

We retrospectively included patients with solid tumors who had DNA-based genome profiles acquired through targeted sequencing from August 2015 to May 2021. MET fusion-positive (MET+) patients were subsequently selected for clinical and molecular characterization.

RESULTS

We screened 79,803 patients across 27 tumor types and detected 155 putative MET fusions from 122 patients, resulting in an overall prevalence of 0.15%. Lung cancer comprised the majority of MET+ patients (92, 75.4%). Prevalence was markedly higher in liver cancer, biliary tract cancer, and renal cancer (range 0.52%-0.60%). It was lower in ovarian cancer (0.06%). A substantial proportion (48/58, 82.8%) of unique partners were reported for the first time. High heterogeneity was observed for partners, with ST7, HLA-DRB1, and KIF5B as the three most common partners. Mutational landscape analysis of lung adenocarcinoma (n = 32) revealed a high prevalence of TP53 in MET+ alterations, EGFR L858R, EGFR L861Q, and MET amplification.

CONCLUSION

To our knowledge, this is currently the largest study in characterizing MET fusions. Our findings warrant that further clinical validation and mechanistic study may translate into therapeutic avenues for MET+ cancer patients.

DIX domain containing 1 (DIXDC1) modulates VEGFR2 level in vasculatures to regulate embryonic and postnatal retina angiogenesis

Background

In sprouting angiogenesis, VEGFR2 level is regulated via a fine-tuned process involving various signaling pathways. Other than VEGF/VEGFR2 signaling pathway, Wnt/ β-catenin signaling is also important in vascular development. However, the crosstalk between these two signaling pathways is still unknown to date. In this study, we aimed to investigate the role of DIX domain containing 1 (DIXDC1) in vasculature, facilitating the crosstalk between VEGF/VEGFR2 and Wnt/ β-catenin signaling pathways.

Results

In mice, DIXDC1 deficiency delayed angiogenesis at the embryonic stage and suppressed neovascularization at the neonatal stage. DIXDC1 knockdown inhibited VEGF-induced angiogenesis in endothelial cells in vitro by downregulating VEGFR2 expression. DIXDC1 bound Dishevelled Segment Polarity Protein 2 (Dvl2) and polymerized Dvl2 stabilizing VEGFR2 protein via its direct interaction. The complex formation and stability of VEGFR2 was potentiated by Wnt signaling. Moreover, hypoxia elevated DIXDC1 expression and likely modulated both canonical Wnt/β-catenin signaling and VEGFR2 stability in vasculatures. Pathological angiogenesis in DIXDC1 knockout mice was decreased significantly in oxygen-induced retinopathy (OIR) and in wound healing models. These results suggest that DIXDC1 is an important factor in developmental and pathological angiogenesis.

Conclusion

We have identified DIXDC1 as an important factor in early vascular development. These results suggest that DIXDC1 represents a novel regulator of sprouting angiogenesis that links Wnt signaling and VEGFR2 stability and may have a potential role in pathological neovascularization.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12915-022-01240-3.

Circular RNA circ_0000423 promotes gastric cancer cell proliferation, migration and invasion via the microR-582-3p/Disheveled-Axin domain containing 1 axis

For humans, gastric cancer (GC) is a common malignancy. Multiple circular RNAs (circRNAs) have been confirmed to be important cancer-promoting or tumor-suppressive factors. The present study discusses the roles and mechanisms of circ_0000423 in GC development. In this study, circ_0000423 expression in GC patient tissue samples and cell lines was detected via quantitative real-time polymerase chain reaction. Disheveled-Axin domain containing 1 (DIXDC1) expression in GC cells was examined via Western blot. Besides, cell counting kit-8 was utilized for detecting GC cell viability. GC cell migration and invasion were examined through Transwell assays. Bioinformatics and dual-luciferase reporter gene assays were employed to verify the regulatory relationships between microRNA-582-3p (miR-582-3p) and circ_0000423 or DIXDC1. In the present study, we demonstrated that circ_0000423 was highly expressed in GC. Circ_0000423 knockdown suppressed GC cell viability, migration and invasion. Moreover, miR-582-3p was confirmed as a direct target of circ_0000423, and an upstream regulator of DIXDC1. MiR-582-3p inhibition or DIXDC1 overexpression could reverse the above-mentioned effects of knocking down circ_0000423 on GC cells. In conclusion, circ_0000423 facilitates GC progression by modulating the miR-582-3p/DIXDC1 axis.

MicroRNA‑218 inhibits the malignant phenotypes of glioma by modulating the TNC/AKT/AP‑1/TGFβ1 feedback signaling loop

Gliomas are the most malignant and common tumors of the human brain, and the prognosis of glioma patients is extremely poor MicroRNAs (miRNAs or miRs) play critical roles in different types of cancer by performing post-transcriptional regulation of gene expression Although miR-218 has been demonstrated to be decreased in gliomas, its role in gliomas remains largely unknown miR-218 expression was analyzed in gliomas and normal brain tissues (control subjects) using a dataset from The Cancer Genome Atlas A series of in vitro and in vivo studies were performed to determine the biological roles of miR-218 in glioma cells Potential targets of miR-218 were identified using a dual-luciferase reporter system Western blot and dual-luciferase reporter system experiments were performed to evaluate the regulatory effect of miR-218 on the tenascin C (TNC)/AKT/activator protein 1 (AP-1)/transforming growth factor β1 (TGFβ1) pathway It was demonstrated that miR-218 was significantly downregulated in gliomas compared with control subjects, and played potent tumor suppressor roles in glioma cells by inhibiting cell proliferation, colony formation, migration, invasion and tumorigenic potential in nude mice, as well as inducing cell cycle arrest and apoptosis Mechanistically, miR-218 inhibited malignant phenotypes of glioma cells by binding to the 3′-untranslated region of its target TNC and subsequently suppressing its expression As a result, miR-218 could reduce AKT phosphorylation and subsequently inhibit transcriptional activity of AP-1 by reducing JNK phosphorylation, downregulating the expression of TGFβ1, while TGFβ1 was able to, in turn, activate the TNC/AKT/AP-1 signaling axis Our data revealed a previously unknown tumor suppressor role of miR-218 by blocking the TNC/AKT/AP-1/TGFβ1-positive feedback loop in glioma

The Role of Noncoding RNAs in the Regulation of Anoikis and Anchorage-Independent Growth in Cancer

Cancer is a global health concern, and the prognosis of patients with cancer is associated with metastasis. Multistep processes are involved in cancer metastasis. Accumulating evidence has shown that cancer cells acquire the capacity of anoikis resistance and anchorage-independent cell growth, which are critical prerequisite features of metastatic cancer cells. Multiple cellular factors and events, such as apoptosis, survival factors, cell cycle, EMT, stemness, autophagy, and integrins influence the anoikis resistance and anchorage-independent cell growth in cancer. Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), are dysregulated in cancer. They regulate cellular signaling pathways and events, eventually contributing to cancer aggressiveness. This review presents the role of miRNAs and lncRNAs in modulating anoikis resistance and anchorage-independent cell growth. We also discuss the feasibility of ncRNA-based therapy and the natural features of ncRNAs that need to be contemplated for more beneficial therapeutic strategies against cancer.

miR-488-5p and its role in melanoma

Due to their ability to regulate dozens to hundreds of target genes simultaneously and, therefore, influence several oncogenic pathways at the same time, microRNAs are a fascinating research object in melanoma. MicroRNAs have been identified as regulators of tumor proliferation, invasion and metastasis in melanoma. More precisely, it has been published that dysregulation of miR-488 contibutes to the progression of several cancer entities. However, the biological functions of miR-488, in special miR-488-5p in melanoma, remain unclear. This study showed the involvement of miR-488-5p in Wnt/β-catenin pathway and the function as a tumor suppressor. Transfection of miR-488-5p mimic led to inhibition of proliferation, migration, anchorage independent growth and led to induction of apoptosis. These data indicated that miR-488-5p acts as a tumor suppressor and is lost during melanoma development. The loss of miR-488-5p was confirmed in vivo by in situ hybridization on melanoma tissue.

Effects of LY294002 on the function of retinal endothelial cell in vitro

AIM

To study the effects of LY294002 [phosphatidylinositol 3-kinase (PI3K) inhibitor] on the function and mechanisms of retinal endothelial cells (RECs) in vitro.

METHODS

RECs were randomly divided into control group and LY294002 treatment group. RECs in the control group were placed the incubator for hypoxic exposure in vitro. RECs in the LY294002 treatment group were pretreated with LY294002 (40 µmol/L) under hypoxic condition. The expression of matrix metalloproteinase (MMP)-2, MMP-9, vascular endothelial growth factor (VEGF), and apoptosis and proliferation of RECs were evaluated with Western blot, real-time reverse transcription-polymerase chain reaction (RT-PCR), and flow cytometric analysis, correspondently.

RESULTS

Compared with the control group, treating the RECs with LY294002 was able to remarkably inhibit cell proliferation rates (t_1d=2.13, t_2d=2.65, t_3d=2.36, t_4d=2.06, all P<0.05). Flow cytometric analysis indicated that a moderate increase in apoptosis in the LY294002 treatment group compared to the control group (t=2.51, P<0.05). The expression of MMP-2, MMP-9 and VEGF were downregulated in the LY294002 treatment group by Western blot and real-time RT-PCR (all P<0.05).

CONCLUSION

LY294002 regulates the function of RECs by reducing the expression of MMP-2, MMP-9, and VEGF in vitro. LY294002 may provide an effective method for preventing pathological angiogenesis.

DIXDC1 promotes the growth of acute myeloid leukemia cells by upregulating the Wnt/β-catenin signaling pathway

Accumulating evidence suggests that dysregulation of Dishevelled-Axin domain-containing 1 (DIXDC1) is involved in the progression and development of various cancers. However, little is known about the relevance of DIXDC1 in acute myeloid leukemia (AML). In this study, we aimed to investigate the expression status and potential biological function of DIXDC1 in AML. Our results showed that DIXDC1 expression was highly upregulated in AML cell lines and primary AML blasts compared with normal blasts. Knockdown of DIXDC1 by siRNA-mediated gene silencing significantly inhibited proliferation, induced cell cycle arrest, and promoted apoptosis of AML cells in vitro. By contrast, DIXDC1 overexpression promoted proliferation, accelerated cell cycle progression, and reduced apoptosis of AML cells. Moreover, we found that DIXDC1 knockdown decreased the expression of β-catenin and restricted the activation of Wnt signaling. In addition, DIXDC1 knockdown decreased the expression of Wnt/β-catenin target genes, including cyclin D1 and c-myc, while DIXDC1 overexpression had the opposite effect. Notably, β-catenin knockdown partially reversed the oncogenic effect of DIXDC1 in AML cells. Taken together, these results demonstrate that DIXDC1 promotes the growth of AML cells, possibly through upregulating the Wnt/β-catenin signaling pathway. Our study suggests that DIXDC1 may serve as a potential therapeutic target for the treatment of AML.

Inhibition of LY294002 in retinal neovascularization via down-regulation the PI3K/AKT-VEGF pathway in vivo and in vitro

AIM

To investigate the effects of the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 on retinal neovascularization (RNV) in the oxygen-induced retinopathy (OIR) mouse model and human umbilical vein endothelial cells (HUVECs).

METHODS

C57BL/6J mice were randomly divided into normoxia-control, OIR-control and LY294002 treatment groups. LY294002 or phosphate-buffered solution was intraperitoneally injected daily into mouse pups from P6 to P9 in LY294002 treatment group or OIR-control group. Morphological and pathological changes in RNV, as well as expression levels of PI3K, serine-threonine kinase (AKT) and vascular endothelial growth factor (VEGF) were observed. HUVECs treating with LY294002 were exposed to hypoxia; the expression of PI3K, AKT and VEGF were examined by Western blot and RT-PCR analyses.

RESULTS

Compared with the OIR-control group, LY294002 significantly inhibit RNV. Adenosine diphosphatase (ADPase) staining and hematoxylin and eosin staining indicated that the clock hour scores of neovascularization and the nuclei of pre-retinal neovascular cells in the LY294002 treatment group were clearly less than those in the OIR-control group (1.41±0.52 vs 6.20±1.21; 10.50±1.58 vs 22.25±1.82, both P<0.05). Intravitreal injection of LY294002 (in the LY294002 treatment group) markedly decreased PI3K/AKT-VEGF expression compared with the OIR-control group by immunohistochemistry, Western blotting and RT-PCR (all P<0.05). In HUVECs treated with hypoxia, expression of PI3K, AKT and VEGF were downregulated in the hypoxia-LY294002 group (all P<0.05).

CONCLUSION

The PI3K inhibitor LY294002 can inhibit RNV by downregulating PI3K, AKT, and VEGF expression in vivo and in vitro. LY294002 may provide an effective method for preventing retinopathy of prematurity (ROP).

The Antitumor Effect of Xihuang Pill on Treg Cells Decreased in Tumor Microenvironment of 4T1 Breast Tumor-Bearing Mice by PI3K/AKT~AP-1 Signaling Pathway

To study the antitumor effect of Xihuang pill (XHP) on the number of Treg cells in the tumor microenvironment of 4T1 breast tumor-bearing mice by PI3K/AKT/AP-1 pathway, a mouse model was established. Flow cytometry (FCM) and immunohistochemistry (IHC) were used to detect the number of Treg cells in the tumor microenvironment; terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was used to detect the apoptosis of Treg cells in tumor microenvironment. Quantitative real-time PCR (RT-qPCR) was used to detect the mRNA expression of PI3K, AKT, and AP-1 in Treg cells in tumor microenvironment; immunofluorescence (IF) and Western Blot (WB) were used to detect the protein expression of PI3K, AKT, and AP-1 in Treg cells in tumor microenvironment. Compared with the naive control group, the tumor weight in XHP groups decreased significantly (P < 0.05); FCM and IHC results showed that the number of Treg cells in the tumor microenvironment decreased with the dose of XHP groups (P < 0.05); TUNEL staining showed that the number of Treg cells in tumor microenvironment increased with the dose of XHP groups (P < 0.05); RT-qPCR results showed that the mRNA expression of PI3K and AKT in Treg cells decreased with the dose of XHP groups, while RNA expression of AP-1 increased with the dose of XHP groups (P < 0.05); IF and WB results showed that the protein expression of PI3K and AKT in Treg cells decreased with the dose of XHP groups and the protein expression of AP-1 increased with the dose of XHP groups (P < 0.05). The results suggested that XHP decreased the number of Treg cells via inhibiting PI3K and AKT expression and upregulating AP-1 expression in Treg cells and then promoting the apoptosis of Treg cells. Thus, XHP could improve the immunosuppressive state of tumor microenvironment and reverse the immune escape to inhibit tumor growth.

Downregulation of miR-3127-5p promotes epithelial-mesenchymal transition via FZD4 regulation of Wnt/β-catenin signaling in non-small-cell lung cancer

MiR-3127-5p has been implicated as a tumor-suppressive microRNA (miRNA) in non-small-cell lung cancer (NSCLC) and its expression was associated with tumor recurrence and poor prognosis. The aim of this study was to determine whether miR-3127-5p regulates epithelial-mesenchymal transition (EMT) in NSCLC, and to investigate the underlying mechanisms. Using qRT-PCR, we examined the expression levels of miR-3127-5p in a cohort of primary NSCLC specimens with and without distant metastasis. We further performed a series of in vitro and in vivo experiments to investigate the effects and underlying mechanism of miR-3127-5p on EMT, cell migration, invasion, and adhesion in NSCLC. We found that metastatic NSCLC tissues showed markedly downregulated miR-3127-5p expression. Transforming growth factor-β1 (TGF-β1) treatment induced EMT in A549 and H1299 cells, and downregulation of miR-3127-5p could result in the similar effect. Mechanically, we demonstrated that frizzled-4 (FZD4) is a target gene and miR-3127-5p exerts its effects by regulating the Wnt/β-catenin signaling. In addition, the expression levels of FZD4 and miR-3127-5p were also negatively associated in both clinical and xenografted tumors. Overall, these findings suggest that downregulation of miR-3127-5p promotes EMT through activating the Wnt/FZD4/β-catenin signaling pathway and may represent a therapeutic target for NSCLC metastasis.

DIXDC1 contributes to psychiatric susceptibility by regulating dendritic spine and glutamatergic synapse density via GSK3 and Wnt/β-catenin signaling

Mice lacking DIX domain containing-1 (DIXDC1), an intracellular Wnt/β-catenin signal pathway protein, have abnormal measures of anxiety, depression and social behavior. Pyramidal neurons in these animals' brains have reduced dendritic spines and glutamatergic synapses. Treatment with lithium or a glycogen synthase kinase-3 (GSK3) inhibitor corrects behavioral and neurodevelopmental phenotypes in these animals. Analysis of DIXDC1 in over 9000 cases of autism, bipolar disorder and schizophrenia reveals higher rates of rare inherited sequence-disrupting single-nucleotide variants (SNVs) in these individuals compared with psychiatrically unaffected controls. Many of these SNVs alter Wnt/β-catenin signaling activity of the neurally predominant DIXDC1 isoform; a subset that hyperactivate this pathway cause dominant neurodevelopmental effects. We propose that rare missense SNVs in DIXDC1 contribute to psychiatric pathogenesis by reducing spine and glutamatergic synapse density downstream of GSK3 in the Wnt/β-catenin pathway.

MicroRNA-154 Inhibits the Growth and Invasion of Gastric Cancer Cells by Targeting DIXDC1/WNT Signaling

MicroRNAs (miRNAs) have emerged as pivotal regulators of the development and progression of gastric cancer. Studies have shown that miR-154 is a novel cancer-associated miRNA involved in various cancers. However, the role of miR-154 in gastric cancer remains unknown. Here we aimed to investigate the biological function and the potential molecular mechanism of miR-154 in gastric cancer. We found that miR-154 was significantly downregulated in gastric cancer tissues and cell lines. The overexpression of miR-154 significantly repressed the growth and invasion of gastric cancer cells. Bioinformatics analysis and Dual-Luciferase Reporter Assay data showed that miR-154 directly targeted the 3′-untranslated region of Dishevelled–Axin domain containing 1 (DIXDC1). Real-time quantitative polymerase chain reaction and Western blot analyses showed that miR-154 overexpression inhibited DIXDC1 expression. An inverse correlation of miR-154 and DIXDC1 was also demonstrated in gastric cancer specimens. Overexpression of miR-154 also significantly suppressed the activation of WNT signaling. Moreover, restoration of DIXDC1 expression significantly reversed the inhibitory effect of miR-154 overexpression on the cell proliferation, invasion, and WNT signaling in gastric cancer cells. Overall, these results suggest that miR-154 inhibits gastric cancer cell growth and invasion by targeting DIXDC1 and could serve as a potential therapeutic target for the treatment of gastric cancer.

Grb2-associated binder 2 expression and its roles in uveal melanoma invasion

Uveal melanoma (UM) is characterized by high metastasis and poor prognosis. A more improved understanding of the metastatic mechanism in UM cells is essential for the design of molecular therapy. Grb2-associated binder 2 (Gab2) has been reported to serve important roles in the progression of various types of human cancer. However, the role of Gab2 in the migration and invasion of UM remains unclear. The present study sought to further assess the expression of Gab2 in UM and the role of Gab2 in the invasion of UM cells. Clinical UM tissue samples and UM cell lines were analyzed using western blot analysis for the expression of Gab2. RNA interference was used to investigate the effect of Gab2 on the migratory and invasive characteristics of UM cells in vitro. The expression levels of matrix metalloproteinase (MMP)2, MMP9 and fascin in Gab2-knockdown, and control cells were also detected using western blot analysis. A total of 20 clinical UM samples and a subset of UM cell lines were investigated with uniformly high Gab2 expression. In the in vitro experiment, reduction of Gab2 using small interfering RNA inhibited the migration and invasion of UM cells by mediating MMPs, and fascin expression. These data suggest that Gab2 is a useful prognostic marker for UM and a novel therapeutic target for UM metastasis intervention.

Inhibition of DIXDC1 by microRNA-1271 suppresses the proliferation and invasion of prostate cancer cells

Disheveled-Axin domain containing 1 (DIXDC1) is involved in the development and progression of multiple cancers. However, the function significance of DIXDC1 in prostate cancer remains unclear. In this study, we investigated the function of DIXDC1 in prostate cancer and the regulation of DIXDC1 by microRNAs (miRNAs). We found that DIXDC1 was highly expressed in prostate cancer cells. Knockdown of DIXDC1 by small interfering RNAs markedly suppressed proliferation, invasion and Wnt signaling in prostate cancer cells. DIXDC1 was identified as a target gene of miR-1271 by bioinformatics analysis, dual-luciferase reporter assay, real-time quantitative polymerase chain reaction and Western blot analysis. Furthermore, DIXDC1 expression was inversely correlated with miR-1271 expression in prostate cancer tissues. The overexpression of miR-1271 significantly inhibited proliferation, invasion and Wnt signaling in prostate cancer cells. However, the inhibition of miR-1271 exhibits the opposite effects. Moreover, the overexpression of DIXDC1 significantly reversed the inhibitory effects of miR-1271 overexpression. Taken together, our results suggest that DIXDC1 plays an important role in regulating prostate cancer cell proliferation and invasion. Targeting DIXDC1 by miR-1271 may be a promising therapeutic strategy for prostate cancer.

Developmental pathways associated with cancer metastasis: Notch, Wnt, and Hedgehog

Master developmental pathways, such as Notch, Wnt, and Hedgehog, are signaling systems that control proliferation, cell death, motility, migration, and stemness. These systems are not only commonly activated in many solid tumors, where they drive or contribute to cancer initiation, but also in primary and metastatic tumor development. The reactivation of developmental pathways in cancer stroma favors the development of cancer stem cells and allows their maintenance, indicating these signaling pathways as particularly attractive targets for efficient anticancer therapies, especially in advanced primary tumors and metastatic cancers. Metastasis is the worst feature of cancer development. This feature results from a cascade of events emerging from the hijacking of epithelial-mesenchymal transition, angiogenesis, migration, and invasion by transforming cells and is associated with poor survival, drug resistance, and tumor relapse. In the present review, we summarize and discuss experimental data suggesting pivotal roles for developmental pathways in cancer development and metastasis, considering the therapeutic potential. Emerging targeted antimetastatic therapies based on Notch, Wnt, and Hedgehog pathways are also discussed.

Knockdown of DIXDC1 Inhibits the Proliferation and Migration of Human Glioma Cells

DIX domain containing 1 (DIXDC1), the human homolog of coiled-coil-DIX1 (Ccd1), is a positive regulator of Wnt signaling pathway. Recently, it was found to act as a candidate oncogene in colon cancer, non-small-cell lung cancer, and gastric cancer. In this study, we aimed to investigate the clinical significance of DIXDC1 expression in human glioma and its biological function in glioma cells. Western blot and immunohistochemistry analysis showed that DIXDC1 was overexpressed in glioma tissues and glioma cell lines. The expression level of DIXDC1 was evidently linked to glioma pathological grade and Ki-67 expression. Kaplan-Meier curve showed that high expression of DIXDC1 may lead to poor outcome of glioma patients. Serum starvation and refeeding assay indicated that the expression of DIXDC1 was associated with cell cycle. To determine whether DIXDC1 could regulate the proliferation and migration of glioma cells, we transfected glioma cells with interfering RNA-targeting DIXDC1; investigated cell proliferation with Cell Counting Kit (CCK)-8, flow cytometry assays, and colony formation analyses; and investigated cell migration with wound healing assays and transwell assays. According to our data, knockdown of DIXDC1 significantly inhibited proliferation and migration of glioma cells. These data implied that DIXDC1 might participate in the development of glioma, suggesting that DIXDC1 can become a potential therapeutic strategy for glioma.

DIXDC1 promotes tumor proliferation and cell adhesion mediated drug resistance (CAM-DR) via enhancing p-Akt in Non-Hodgkin's lymphomas

DIX domain containing 1 (DIXDC1), is a human homolog of Ccd1, a DIX domain containing protein in zebrafish. The present study was undertaken to determine the expression and biologic function of DIXDC1 in Non-Hodgkin's lymphoma (NHL). Clinically, we detected that the expression of DIXDC1 was significantly lower in the indolent lymphomas compared with the progressive lymphomas by immunohistochemistry analysis. Functionally, we found that DIXDC1 could promote cell proliferation via modulating cell cycle progression and PI3K/AKT signaling pathway in NHLs. Moreover, we confirmed that DIXDC1 was involved in the process of lymphoma cell adhesion mediated drug resistance (CAM-DR). Adhesion to fibronectin (FN) or HS-5 up-regulated DIXDC1 expression, and up-regulation of DIXDC1 resulted in an increased expression of p-AKT, which promoted CAM-DR. Our finding supports the role of DIXDC1 in cell proliferation, cell cycle and CAM-DR in NHLs. We propose that inhibition of DIXDC1 expression may be a novel therapeutic approach for NHLs patients, and it may be a target for drug resistance.

Reversine Induced Multinucleated Cells, Cell Apoptosis and Autophagy in Human Non-Small Cell Lung Cancer Cells

Reversine, an A3 adenosine receptor antagonist, has been shown to induce differentiated myogenic-lineage committed cells to become multipotent mesenchymal progenitor cells. We and others have reported that reversine has an effect on human tumor suppression. This study revealed anti-tumor effects of reversine on proliferation, apoptosis and autophagy induction in human non-small cell lung cancer cells. Treatment of these cells with reversine suppressed cell growth in a time- and dosage-dependent manner. Moreover, polyploidy occurred after reversine treatment. In addition, caspase-dependent apoptosis and activation of autophagy by reversine in a dosage-dependent manner were also observed. We demonstrated in this study that reversine contributes to growth inhibition, apoptosis and autophagy induction in human lung cancer cells. Therefore, reversine used as a potential therapeutic agent for human lung cancer is worthy of further investigation.

Upregulated expression of DIXDC1 in intestinal-type gastric carcinoma: co-localization with β-catenin and correlation with poor prognosis

Background

DIXDC1 (Dishevelled-Axin domain containing 1) is a positive regulator of the Wnt pathway. In the field of cancer research, the role of DIXDC1 is unclear. Our previous in vitro study showed that DIXDC1 enhances β-catenin nuclear accumulation in gastric cancer cell lines. The aim of this study was to detect the expression of DIXDC1 in different histological subtypes of gastric carcinoma and to evaluate the correlation between the expression of DIXDC1 and β-catenin localization and clinicopathological parameters, including patients’ survival.

Methods

Immunohistochemical staining was performed to characterize the expression of DIXDC1 and β-catenin in archived materials from 259 cases of gastric carcinoma. The χ2 test and the Fisher’s test were used to analyze correlations between DIXDC1 expression, β-catenin localization, and clinicopathological parameters. Univariate analyses were performed using the Kaplan–Meier method, and the survival difference between groups was assessed by the log-rank test. Multivariate analysis was performed using the Cox proportional hazards regression model.

Results

Positive DIXDC1 staining was detected in tumor cells in 123 of 259 (47.5 %) cases. DIXDC1 expression in gastric carcinoma was significantly correlated with the histological intestinal-type (P < 0.001), the depth of tumor invasion (P < 0.001) and the lymph node metastasis (P = 0.006). In the intestinal-type, DIXDC1 was correlated with the nuclear and cytoplasmic β-catenin expression (P = 0.002). Kaplan–Meier analysis indicated that patients with high DIXDC1 expression had poor disease-specific survival (P < 0.001), especially in the intestinal-type. Moreover, multivariate regression analysis showed that positive expression of DIXDC1 was an independent prognostic predictor of intestinal-type gastric carcinoma.

Conclusion

Our study indicated that DIXDC1 is a significant independent prognostic indicator in intestinal-type gastric carcinoma that plays an important role in carcinogenesis and progression of gastric carcinoma through the Wnt signaling pathway.

The transcriptional PPARβ/δ network in human macrophages defines a unique agonist-induced activation state

Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) is a lipid ligand-inducible transcription factor with established metabolic functions, whereas its anti-inflammatory function is poorly understood. To address this issue, we determined the global PPARβ/δ-regulated signaling network in human monocyte-derived macrophages. Besides cell type-independent, canonical target genes with metabolic and immune regulatory functions we identified a large number of inflammation-associated NFκB and STAT1 target genes that are repressed by agonists. Accordingly, PPARβ/δ agonists inhibited the expression of multiple pro-inflammatory mediators and induced an anti-inflammatory, IL-4-like morphological phenotype. Surprisingly, bioinformatic analyses also identified immune stimulatory effects. Consistent with this prediction, PPARβ/δ agonists enhanced macrophage survival under hypoxic stress and stimulated CD8⁺ T cell activation, concomitantly with the repression of immune suppressive target genes and their encoded products CD274 (PD-1 ligand), CD32B (inhibitory Fcγ receptor IIB) and indoleamine 2,3-dioxygenase 1 (IDO-1), as well as a diminished release of the immune suppressive IDO-1 metabolite kynurenine. Comparison with published data revealed a significant overlap of the PPARβ/δ transcriptome with coexpression modules characteristic of both anti-inflammatory and pro-inflammatory cytokines. Our findings indicate that PPARβ/δ agonists induce a unique macrophage activation state with strong anti-inflammatory but also specific immune stimulatory components, pointing to a context-dependent function of PPARβ/δ in immune regulation.

MiR-204 inhibits human NSCLC metastasis through suppression of NUAK1

Background:

Lung cancer is a leading cause of cancer-related mortality worldwide and non-small-cell lung carcinoma (NSCLC) is responsible for almost 80% of lung cancer-related deaths. Identifying novel molecules that can repress the invasiveness and metastasis of lung cancer will facilitate the development of new antilung cancer strategies. The aim of this study is to determine the roles of NUAK1 (a downstream of Akt) and miR-204 in the invasiveness and metastasis of NSCLC and to reveal the correlation between NUAK1 and miR-204.

Methods:

The expression of NUAK1 in primary human NSCLC tissues was evaluated by immunohistochemistry. Real-time PCR was employed to measure the expression level of miR-204. The effect of NUAK1 and miR204 on the prognosis of NSCLC patients was evaluated by log-rank test. The siRNA transfection was used to manipulate the expression levels of NUAK1 and miR204 in cancer cells. Chemotaxis assay, Scratch assay, and Matrigel invasion assay were performed to evaluate the migration and invasion of cells. Cellular F-actin measurement was used to measure F-actin polymerisation in lung cancer cells. Western blot was used to detect the expression levels of corresponding proteins. The Luciferase assay and RNA immunoprecipitation were used to confirm the actual binding site of miR-204 to 3′UTR of NUAK1.

Results:

Increased expression of NUAK1 is correlated with the invasiveness and metastasis of human NSCLC. Knockdown of NUAK1 inhibited cell migration and invasion. In addition, this study showed that NUAK1 influenced mTOR phosphorylation and induced the phosphorylation of p70S6K1 and eukaryotic initiation factor 4E-binding protein1 (4E-BP1), two downstream targets of mTOR in NSCLC cells. At the same time, decreased expression of miR-204 promoted NSCLC progression and, contrarily, manipulated upregulation of miR-204-inhibited cell migration and invasion. There is clinical relevance between miR-204 downregulation and NUAK1 upregulation in human NSCLC. Furthermore, we found that miR-204 inhibited NSCLC tumour invasion by directly targeting and downregulating NUAK1 expression. Finally, our data suggested that the downregulation of miR-204 was due to hypermethylation of its promoter region.

Conclusions:

Our results indicate that NUAK1 is excessively expressed in NSCLC and plays important roles in NSCLC invasion. The miR-204 acts as a tumour suppressor by inhibiting NUAK1 expression in NSCLC. Both NUAK1 and miR-204 may serve as potential targets of NSCLC therapy.