Stress-induced epinephrine promotes hepatocellular carcinoma progression via the USP10-PLAGL2 signaling loop

Hepatocellular carcinoma (HCC) is associated with a poor prognosis. Our previous study demonstrated that Pleomorphic adenoma gene like-2 (PLAGL2) was a potential therapeutic target in HCC. However, the mechanisms that lead to the upregulation of PLAGL2 in HCC remain unclear. The present study revealed that stress-induced epinephrine increased the expression of PLAGL2, thereby promoting the progression of HCC. Furthermore, PLAGL2 knockdown inhibited epinephrine-induced HCC development. Mechanistically, epinephrine upregulated ubiquitin-specific protease 10 (USP10) to stabilize PLAGL2 via the adrenergic β-receptor-2-c-Myc (ADRB2-c-Myc) axis. Furthermore, PLAGL2 acted as a transcriptional regulator of USP10, forming a signaling loop. Taken together, these results reveal that stress-induced epinephrine activates the PLAGL2-USP10 signaling loop to enhance HCC progression. Furthermore, PLAGL2 plays a crucial role in psychological stress-mediated promotion of HCC progression.

TBX18 knockdown sensitizes esophageal squamous cell carcinoma to radiotherapy by blocking the CHN1/RhoA axis

OBJECTIVE

Radioresistance is a challenge in the effective treatment of esophageal squamous cell carcinoma (ESCC). Herein, this research ascertained whether TBX18 reduced the radiosensitivity of ESCC.

METHODS

Bioinformatics analysis was utilized to retrieve differentially expressed genes. Then, the expression of corresponding candidate genes was tested using qRT-PCR in ESCC clinical specimens, and TBX18 was selected for subsequent experiments. The binding between TBX18 and CHN1 was evaluated by dual-luciferase reporter and ChIP assays, and the relationship between CHN1 and RhoA was identified by GST pull-down. Ectopic expression or knockdown experiments and radiation treatment were performed in cells and the nude mouse xenograft model to clarify the impacts of TBX18, CHN1, and RhoA on radiosensitivity in ESCC.

RESULTS

Bioinformatics analysis and qRT-PCR retrieved upregulated TBX18 in ESCC for the follow-up study. Additionally, TBX18 was positively correlated with CHN1 in ESCC clinical specimens. Mechanistically, TBX18 bound to the CHN1 promoter region to transcriptionally activate CHN1, thus elevating RhoA activity. Moreover, TBX18 knockdown reduced ESCC cell proliferation and migration while augmenting their apoptosis after radiation, which was negated by further overexpressing CHN1 or RhoA. CHN1 or RhoA knockdown diminished ESCC cell proliferation and migration, as well as enhanced cell apoptosis, subsequent to radiation. Likewise, TBX18 overexpression increased ESCC cell autophagy after radiation, which was partially reversed by knockdown of RhoA. The results of in vivo xenograft experiments in nude mice were concurrent with the in vitro results.

CONCLUSION

TBX18 knockdown lowered CHN1 transcription and thus reduced RhoA activity, which sensitized ESCC cells to radiotherapy.

TEAD4 predicts poor prognosis and transcriptionally targets PLAGL2 in serous ovarian cancer

The oncogenic function of TEA domain transcription factor 4 (TEAD4) has been confirmed in multiple human malignancies, while its potential role and regulatory mechanism in serous ovarian cancer progression are left unknown. By the gene expression analyses from Gene Expression Profiling Interactive Analysis (GEPIA) database, TEAD4 expression is shown to be up-regulated in serous ovarian cancer samples. Here, we confirmed the high expression of TEAD4 in clinical serous ovarian cancer specimens. In the following functional experiments, we found that TEAD4 overexpression promoted serous ovarian cancer malignant phenotypes, including proliferation, migration and invasion in serous ovarian cancer SK-OV-3 and OVCAR-3 cells, while TEAD4 knockout exerted the opposite function. The tumor growth inhibition of TEAD4 depletion was also affirmed by a Xenograft model in mice. In addition, this phenotypic deterioration induced by TEAD4 overexpression was diminished by PLAG1 like zinc finger 2 (PLAGL2) silencing. More importantly, combined with the results of the dual-luciferase assay, the transcriptional regulation of TEAD4 on PLAGL2 promoter was evidenced. Our results showed that the cancer-promoting gene TEAD4 was involved in serous ovarian cancer progression via targeting PLAGL2 at the transcriptional level.

PLAGL2 promotes the stemness and is upregulated by transcription factor E2F1 in human lung cancer

This study mainly focuses on revealing the role of PLAGL2 in lung cancer stemness. In vitro and in vivo experiments were performed to evaluate the effects of PLAGL2 on lung cancer cell stemness. Mechanistic analysis using luciferase reporter and ChIP assays were implemented to reveal the underlying mechanisms. The transcriptional factor E2F1 transcriptionally activated PLAGL2 expression via directly binding to PLAGL2 promoter in lung cancer cells. Moreover, PLAGL2 promoted the stemness of lung cancer cells dependent on E2F1-mediated transcriptional activation. This study provides a potential target for lung cancer progression.

ZFTA-RELA Dictates Oncogenic Transcriptional Programs to Drive Aggressive Supratentorial Ependymoma

More than 60% of supratentorial ependymomas harbor a ZFTA-RELA (ZRfus) gene fusion (formerly C11orf95-RELA). To study the biology of ZRfus, we developed an autochthonous mouse tumor model using in utero electroporation (IUE) of the embryonic mouse brain. Integrative epigenomic and transcriptomic mapping was performed on IUE-driven ZRfus tumors by CUT&RUN, chromatin immunoprecipitation sequencing, assay for transposase-accessible chromatin sequencing, and RNA sequencing and compared with human ZRfus-driven ependymoma. In addition to direct canonical NFκB pathway activation, ZRfus dictates a neoplastic transcriptional program and binds to thousands of unique sites across the genome that are enriched with PLAGL family transcription factor (TF) motifs. ZRfus activates gene expression programs through recruitment of transcriptional coactivators (Brd4, Ep300, Cbp, Pol2) that are amenable to pharmacologic inhibition. Downstream ZRfus target genes converge on developmental programs marked by PLAGL TF proteins, and activate neoplastic programs enriched in Mapk, focal adhesion, and gene imprinting networks. SIGNIFICANCE: Ependymomas are aggressive brain tumors. Although drivers of supratentorial ependymoma (ZFTA- and YAP1-associated gene fusions) have been discovered, their functions remain unclear. Our study investigates the biology of ZFTA-RELA-driven ependymoma, specifically mechanisms of transcriptional deregulation and direct downstream gene networks that may be leveraged for potential therapeutic testing.This article is highlighted in the In This Issue feature, p. 2113.

Systems Biomedicine of Primary and Metastatic Colorectal Cancer Reveals Potential Therapeutic Targets

Colorectal cancer (CRC) is one of the major causes of cancer deaths across the world. Patients' survival at time of diagnosis depends mainly on stage of the tumor. Therefore, understanding the molecular mechanisms from low-grade to high-grade stages of cancer that lead to cellular migration from one tissue/organ to another tissue/organ is essential for implementing therapeutic approaches. To this end, we performed a unique meta-analysis flowchart by identifying differentially expressed genes (DEGs) between normal, primary (primary sites), and metastatic samples (Colorectal metastatic lesions in liver and lung) in some Test datasets. DEGs were employed to construct a protein-protein interaction (PPI) network. A smaller network containing 39 DEGs was then extracted from the PPI network whose nodes expression induction or suppression alone or in combination with each other would inhibit tumor progression or metastasis. These DEGs were then verified by gene expression profiling, survival analysis, and multiple Validation datasets. We suggested for the first time that downregulation of mitochondrial genes, including ETHE1, SQOR, TST, and GPX3, would help colorectal cancer cells to produce more energy under hypoxic conditions through mechanisms that are different from "Warburg Effect". Augmentation of given antioxidants and repression of P4HA1 and COL1A2 genes could be a choice of CRC treatment. Moreover, promoting active GSK-3β together with expression control of EIF2B would prevent EMT. We also proposed that OAS1 expression enhancement can induce the anti-cancer effects of interferon-gamma, while suppression of CTSH hinders formation of focal adhesions. ATF5 expression suppression sensitizes cancer cells to anchorage-dependent death signals, while LGALS4 induction recovers cell-cell junctions. These inhibitions and inductions would be another combinatory mechanism that inhibits EMT and cell migration. Furthermore, expression inhibition of TMPO, TOP2A, RFC3, GINS1, and CKS2 genes could prevent tumor growth. Besides, TRIB3 suppression would be a promising target for anti-angiogenic therapy. SORD is a poorly studied enzyme in cancer, found to be upregulated in CRC. Finally, TMEM131 and DARS genes were identified in this study whose roles have never been interrogated in any kind of cancer, neither as a biomarker nor curative target. All the mentioned mechanisms must be further validated by experimental wet-lab techniques.

PLAGL2-EGFR-HIF-1/2α Signaling Loop Promotes HCC Progression and Erlotinib Insensitivity

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide, hence a major public health threat. Pleomorphic adenoma gene like-2 (PLAGL2) has been reported to play a role in tumorigenesis. However, its precise function in HCC remains poorly understood.

APPROACH AND RESULTS

In this study, we demonstrated that PLAGL2 was up-regulated in HCC compared with that of adjacent nontumorous tissues and also correlated with overall survival times. We further showed that PLAGL2 promoted HCC cell proliferation, migration, and invasion both in vitro and in vivo. PLAGL2 expression was positively correlated with epidermal growth factor receptor (EGFR) expression. Mechanistically, this study demonstrated that PLAGL2 functions as a transcriptional regulator of EGFR and promotes HCC cell proliferation, migration, and invasion through the EGFR-AKT pathway. Moreover, hypoxia was found to significantly induce high expression of PLAGL2, which promoted hypoxia inducible factor 1/2 alpha subunit (HIF1/2A) expression through EGFR. Therefore, this study demonstrated that a PLAGL2-EGFR-HIF1/2A signaling loop promotes HCC progression. More importantly, PLAGL2 expression reduced hepatoma cells' response to the anti-EGFR drug erlotinib. PLAGL2 knockdown enhanced the response to erlotinib.

CONCLUSIONS

This study reveals the pivotal role of PLAGL2 in HCC cell proliferation, metastasis, and erlotinib insensitivity. This suggests that PLAGL2 can be a potential therapeutic target of HCC.

Tissue microRNA expression profiling in hepatic and pulmonary metastatic melanoma

Malignant melanoma has a propensity for the development of hepatic and pulmonary metastases. MicroRNAs (miRs) are small, noncoding RNA molecules containing about 22 nucleotides that mediate protein expression and can contribute to cancer progression. We aim to identify clinically useful differences in miR expression in metastatic melanoma tissue. RNA was extracted from formalin-fixed, paraffin-embedded samples of hepatic and pulmonary metastatic melanoma, benign, nevi, and primary cutaneous melanoma. Assessment of miR expression was performed on purified RNA using the NanoString nCounter miRNA assay. miRs with greater than twofold change in expression when compared to other tumor sites (P value ≤ 0.05, modified t-test) were identified as dysregulated. Common gene targets were then identified among dysregulated miRs unique to each metastatic site. Melanoma metastatic to the liver had differential expression of 26 miRs compared to benign nevi and 16 miRs compared to primary melanoma (P < 0.048). Melanoma metastatic to the lung had differential expression of 19 miRs compared to benign nevi and 10 miRs compared to primary melanoma (P < 0.024). Compared to lung metastases, liver metastases had greater than twofold upregulation of four miRs, and 4.2-fold downregulation of miR-200c-3p (P < 0.0081). These findings indicate that sites of metastatic melanoma have unique miR profiles that may contribute to their development and localization. Further investigation of the utility of these miRs as diagnostic and prognostic biomarkers and their impact on the development of metastatic melanoma is warranted.

MicroRNA-214-3p targets the PLAGL2-MYH9 axis to suppress tumor proliferation and metastasis in human colorectal cancer

Evidence has shown that microRNAs (miRNAs) participate in the progression of CRC. Previous studies have indicated that miR-214-3p is abnormally expressed in various malignant tumors. However, the biological function it plays in CRC and the potential mechanism are unclear. Here, we demonstrated that miR-214-3p was obviously downregulated in CRC. Moreover, we found a strong correlation between the miR-214-3p level and tumor size and lymphatic metastasis. Furthermore, when miR-214-3p was decreased by an Lv-miR-214-3p inhibitor, the proliferation and migration of SW480 and HCT116 cells were significantly increased. As expected, the ability of proliferation and migration was significantly suppressed when miR-214-3p was overexpressed in DLD1 cells. According to the dual-luciferase reporter results, PLAGL2 was found to be a direct downstream molecule of miR-214-3p. Chromatin immunoprecipitation (CHIP) confirmed that MYH9, a well-known cytoskeleton molecule in CRC, was a direct targeting gene of PLAGL2. Silencing PLAGL2 or MYH9 could reverse the effect of a miR-214-3p inhibitor on CRC cells. In summary, our studies proved that low expression of miR-214-3p and overexpression of downstream PLAGL2 in CRC indicated a poor prognosis. MiR-214-3p suppressed the malignant behaviors of colorectal cancer by regulating the PLAGL2/MYH9 axis. MiR-214-3p might be a novel therapeutic target or prognostic marker for CRC.

PLAG1 silencing promotes cell chemosensitivity in ovarian cancer via the IGF2 signaling pathway

Ovarian cancer (OC) is one of the most lethal gynecological diseases. Novel prognostic biomarkers and therapeutic targets for OC are urgently required. The aim of this study was to investigate the mechanisms that govern how pleomorphic adenoma gene 1 (PLAG1) influences the biological processes and chemosensitivity of OC cells via the insulin‑like growth factor‑2 (IGF2) signaling pathway. Differentially expressed genes in OC were selected based on bioinformatics data. OC and adjacent tissue specimen were collected, followed by the determination of the expression of PLAG1 and IGF2 signaling pathway‑associated genes. The regulatory mechanisms of PLAG1 in OC cells were analyzed following treatment with pcDNA or small interfering RNA (siRNA), and included the assessment of cell proliferation, migration, invasion and cisplatin resistance. PLAG1 was identified as an upregulated gene in OC. OC tissues exhibited increased expression of PLAG1 and IGF2 compared with the controls. Moreover, PLAG1 was observed to positively regulate the IGF2 signaling pathway. The siRNA‑mediated silencing of PLAG1 resulted in decreased expression of IGF2, IGF1 receptor and insulin receptor substrate 1, as well as inhibited proliferation, migration, invasion and cisplatin resistance of OC cells. Furthermore, the effect of PLAG1 was dependent on IGF2. PLAG1 may therefore be considered as a possible target for the treatment of OC.

PLAGL2 promotes epithelial-mesenchymal transition and mediates colorectal cancer metastasis via β-catenin-dependent regulation of ZEB1

Background

We previously demonstrated that the pleomorphic adenoma gene like-2 (PLAGL2) is involved in the pathogenesis of Hirschsprung disease. Enhanced PLAGL2 expression was observed in several malignant tumours. However, the exact function of PLAGL2 and its underlying mechanism in colorectal cancer (CRC) remain largely unknown.

Methods

Immunohistochemical analysis of PLAGL2 was performed. A series of in vitro and in vivo experiments were conducted to reveal the role of PLAGL2 in the progression of CRC.

Results

Enhanced PLAGL2 expression was significantly associated with EMT-related proteins in CRC. The data revealed that PLAGL2 promotes CRC cell proliferation, migration, invasion and EMT both in vitro and in vivo. Mechanistically, PLAGL2 promoted the expression of ZEB1. PLAGL2 enhanced the expression and nuclear translocation of β-catenin by decreasing its phosphorylation. The depletion of β-catenin neutralised the regulation of ZEB1 that was caused by enhanced PLAGL2 expression. The small-molecule inhibitor PNU-74654, also impaired the enhancement of ZEB1 that resulted from the modified PLAGL2 expression. The depletion of ZEB1 could block the biological function of PLAGL2 in CRC cells.

Conclusions

Collectively, our findings suggest that PLAGL2 mediates EMT to promote colorectal cancer metastasis via β-catenin-dependent regulation of ZEB1.

PLAGL2 and POFUT1 are regulated by an evolutionarily conserved bidirectional promoter and are collaboratively involved in colorectal cancer by maintaining stemness

Background

Our previous study revealed that PLAGL2 or POFUT1 can promote tumorigenesis and maintain significant positive correlations in colorectal cancer (CRC). However, the mechanism leading to the co-expression and the underlying functional and biological implications remain unclear.

Methods

Clinical tumor tissues and TCGA dataset were utilized to analyze the co-expression of PLAGL2 and POFUT1. Luciferase reporter assays, specially made bidirectional promoter vectors and ectopic expression of 3’UTR were employed to study the mechanisms of co-expression. In vitro and in vivo assays were performed to further confirm the oncogenic function of both. The sphere formation assay, immunofluorescence, Western blot and qRT-PCR were performed to investigate the effect of both genes in colorectal cancer stem cells (CSCs).

Findings

PLAGL2 and POFUT1 maintained co-expression in CRC (r = 0.91, p < .0001). An evolutionarily conserved bidirectional promoter, rather than post-transcriptional regulation by competing endogenous RNAs, caused the co-expression of PLAGL2 and POFUT1 in CRC. The bidirectional gene pair PLAGL2/POFUT1 was subverted in CRC and acted synergistically to promote colorectal tumorigenesis by maintaining stemness of colorectal cancer stem cells through the Wnt and Notch pathways. Finally, PLAGL2 and POFUT1 share transcription factor binding sites, and introducing mutations into promoter regions with shared transcription regulatory elements led to a decrease in the PLAGL2/POFUT1 promoter activity in both directions.

Interpretation

Our team identified for the first time a bidirectional promoter pair oncogene, PLAGL2-POFUT1, in CRC. The two genes synergistically promote the progression of CRC and affect the characteristics of CSCs, which can offer promising intervention targets for clinicians and researchers.

Fund

National Nature Science Foundation of China, the Hunan province projects of Postgraduate Independent Exploration and Innovation of Central South University.

Accessible quantitative phase imaging in confocal microscopy with sinusoidal-phase synthetic optical holography

We present a technically simple implementation of quantitative phase imaging in confocal microscopy based on synthetic optical holography with sinusoidal-phase reference waves. Using a Mirau interference objective and low-amplitude vertical sample vibration with a piezo-controlled stage, we record synthetic holograms on commercial confocal microscopes (Nikon, model: A1R; Zeiss: model: LSM-880), from which quantitative phase images are reconstructed. We demonstrate our technique by stain-free imaging of cervical (HeLa) and ovarian (ES-2) cancer cells and stem cell (mHAT9a) samples. Our technique has the potential to extend fluorescence imaging applications in confocal microscopy by providing label-free cell finding, monitoring cell morphology, as well as non-perturbing long-time observation of live cells based on quantitative phase contrast.

Increased miR-214 expression suppresses cell migration and proliferation in Hirschsprung disease by interacting with PLAGL2

BACKGROUND

The miR-214 has been reported to be associated with various diseases, but its involvement in the pathophysiology of Hirschsprung disease (HSCR) is almost completely unexplored.

METHODS

In our study, we conducted a series of experiments to unravel the biological role of miR-214 in the pathophysiology of HSCR. qRT-PCR and western blotting were utilized to investigate the relative expression levels of miR-214, mRNAs, and proteins of related genes in colon tissues from 20 controls without HSCR and 24 patients with HSCR. The potential biological role of miR-214 in two cell lines (SKN-SH and SH-SY5Y) was assessed using the CCK8 assay, EdU staining, transwell assay, and flow cytometry. The dual-luciferase reporter assay was used to confirm PLAGL2 as a common target gene of miR-214.

RESULTS

All results suggested that miR-214 is upregulated in HSCR tissue samples compared with controls. Additionally, we found that miR-214 could inhibit cell proliferation and migration by directly downregulating the expression of PLAGL2, and the extent of the miR-214-mediated inhibitory effects could be rescued by a PLAGL2 overexpression plasmid.

CONCLUSION

Our results revealed that miR-214 is indeed involved in the pathophysiology of HSCR and suppresses cell proliferation and migration by directly downregulating PLAGL2 in cell models.

DNA-methylation-mediated silencing of miR-486-5p promotes colorectal cancer proliferation and migration through activation of PLAGL2/IGF2/β-catenin signal pathways

As one of the most common cancers worldwide, colorectal cancer (CRC) causes a large number of mortality annually. Aberrant expression of microRNAs (miRNAs) is significantly associated with the initiation and development of CRC. Further investigations regarding the regulatory mechanism of miRNAs is warranted. In this study, we discovered that miR-486-5p was remarkably downregulated in CRC, which partially results from higher DNA methylation in the promoter region detected by using methylation-specific PCR, bisulfite sequencing PCR, and DNA demethylation treatment. Besides, decreased miR-486-5p was obviously associated with advanced TNM stage, larger tumor size, lymphatic metastasis, and poor prognosis in CRC. Upregulated miR-486-5p inhibited the proliferation and migration of CRC through targeting PLAGL2 expression and subsequent repressing IGF/β-catenin signal pathways both in vitro and in vivo. Notably, plasma miR-486-5p expression was significantly upregulated in CRC patients and we identified plasma miR-486-5p as a novel diagnostic biomarker of CRC using receiver operating characteristic (ROC) curve analysis. Moreover, exploration in GEO dataset revealed that circulating miR-486-5p is tumor derived through being packaged into secretory exosomes. Taken together, our data demonstrated that miR-486-5p promotes colorectal cancer proliferation and migration through activation of PLAGL2/IGF2/β-catenin signal pathway, which is a promising therapeutic target of CRC treatment.

DJ-1 promotes colorectal cancer progression through activating PLAGL2/Wnt/BMP4 axis

Metastasis remains a big barrier for the clinical treatment of colorectal cancer (CRC). Our previous proteomics analysis identified DJ-1 as a potential metastasis biomarker of CRC. In this study, we found that DJ-1 was upregulated in CRC. The levels of DJ-1 were closely correlated with the depths of invasion and predicted patient outcome. Enforced expression of DJ-1 could enhance CRC proliferation and metastasis in vitro and in vivo by stimulating Wnt-β-catenin signaling. Specifically, DJ-1-induced β-catenin nuclear translocation stimulated TCF transcription activity, which promoted BMP4 expression for CRC cell migration and invasion, and elevated CCND1 expression for CRC cell proliferation, respectively. Furthermore, DJ-1-induced Wnt signaling activation was dependent on PLAGL2 expression. In conclusion, our study demonstrates that DJ-1 can promote CRC metastasis by activating PLAGL2-Wnt-BMP4 axis, suggesting novel therapeutic opportunities for postoperative adjuvant therapy in CRC patients.

MiR-449a suppresses cell migration and invasion by targeting PLAGL2 in breast cancer

BACKGROUND

Breast cancer is one of the most common malignancies worldwide. However, the detailed molecular mechanisms underlying breast cancer metastasis are still incompletely clear. MicroRNAs (miRNAs) play a crucial role in cancer metastasis. In this study, we aimed to analyze the expression and function of miR-449a in breast cancer.

MATERIAL AND METHODS

A total of 15 human primary breast cancer tissues and adjacent non-cancerous tissues (10 pairs) were obtained. MiR-449a was examined in tumor tissues and adjacent nontumorous tissues of breast cancer patients and cell lines by real-time PCR. The protein expression levels were analyzed by western blot and immunohistochemistry staining. Luciferase reporter assays was used to validate the target of miR-449a. The effect of miR-449a on breast cancer cell migration and invasion were studied in vitro and in vivo.

RESULTS

The expression levels of miR-449a were significantly decreased in breast cancer tissues and cell lines. Overexpression of miR-449a suppressed breast cancer cell proliferation, clone formation, migration, invasion and metastasis in vitro and in vivo. Pleomorphic adenoma gene like-2 (PLAGL2) was identified as a major target of miR-449a. Both overexpression of miR-449a inhibited the expression of PLAGL2 significantly and the knockdown of PLAGL2 expression inhibited the breast cancer cell proliferation and metastasis.

CONCLUSION

We demonstrate the miR-449a tumor suppressor role in breast cancer cell migration and invasion via targeting PLAGL2. These findings suggesting that miR-449a/PLAGL2 could serve as a therapeutic strategy for targeting breast cancer.

Pleomorphic adenoma gene like-2 induces epithelial-mesenchymal transition via Wnt/β-catenin signaling pathway in human colorectal adenocarcinoma

Epithelial-mesenchymal transition (EMT) is a critical step in the acquisition of metastatic and invasive power for tumor cells. Colorectal adenocarcinoma (CRC) is a common cancer where metastasis is directly linked to patient survival. Recent studies show that pleomorphic adenoma gene like-2 (PLAGL2) could induce tumor EMT and is an independent predictive factor associated with poor prognosis in cancer. In the present study, we confirmed the role of PLAGL2 in the prognosis of CRC patients and provide molecular evidence of PLAGL2 promoted EMT in CRC cell line SW480. We found that PLAGL2 expression was upregulated in the paraffin-embedded CRC tissues compared to borderline or benign tissues. Experimental EMT induced by PLAGL2 plasmid transfection proved PLAGL2 protein overexpression could enhance the cell scratch wound-healing and Transwell ability and significantly upregulated mesenchymal marker proteins, N-cadherin and vimentin and concurrently downregulated epithelial marker of E-cadherin. Subsequently, through western blot assay, we found that PLAGL2 could activate the Wnt-signaling component β-catenin in the nuclei. More CRC cell metastasis to the lungs was observed when the PLAGL2 overexpressing SW480 cells were injected into the tail vein of rats, compared with the cell control and PLAGL2 silence group. Our findings indicated that PLAGL2 might be a very upstream key molecule regulating EMT involved in Wnt/β-catenin signaling pathway.

WNT signaling in glioblastoma and therapeutic opportunities

WNTs and their downstream effectors regulate proliferation, death, and migration and cell fate decision. Deregulation of WNT signaling is associated with various cancers including GBM, which is the most malignant primary brain cancer. In this review, we will summarize the experimental evidence supporting oncogenic roles of WNT signaling in GBM and discuss current progress in the targeting of WNT signaling as an anti-cancer approach. In particular, we will focus on (1) genetic and epigenetic alterations that lead to aberrant WNT pathway activation in GBM, (2) WNT-mediated control of GBM stem cell maintenance and invasion, and (3) cross-talk between WNT and other signaling pathways in GBM. We will then review the discovery of agents that can inhibit WNT signaling in preclinical models and the current status of human clinical trials.