Concurrent ependymal and ganglionic differentiation in a subset of supratentorial neuroepithelial tumors with EWSR1-PLAGL1 rearrangement.

Neuroepithelial tumors with fusion of PLAGL1 or amplification of PLAGL1/PLAGL2 have recently been described often with ependymoma-like or embryonal histology respectively. To further evaluate emerging entities with PLAG-family genetic alterations, the histologic, molecular, clinical, and imaging features are described for 8 clinical cases encountered at St. Jude (EWSR1-PLAGL1 fusion n = 6; PLAGL1 amplification n = 1; PLAGL2 amplification n = 1). A histologic feature observed on initial resection in a subset (4/6) of supratentorial neuroepithelial tumors with EWSR1-PLAGL1 rearrangement was the presence of concurrent ependymal and ganglionic differentiation. This ranged from prominent clusters of ganglion cells within ependymoma/subependymoma-like areas, to interspersed ganglion cells of low to moderate frequency among otherwise ependymal-like histology, or focal areas with a ganglion cell component. When present, the combination of ependymal-like and ganglionic features within a supratentorial neuroepithelial tumor may raise consideration for an EWSR1-PLAGL1 fusion, and prompt initiation of appropriate molecular testing such as RNA sequencing and methylation profiling. One of the EWSR1-PLAGL1 fusion cases showed subclonal INI1 loss in a region containing small clusters of rhabdoid/embryonal cells, and developed a prominent ganglion cell component on recurrence. As such, EWSR1-PLAGL1 neuroepithelial tumors are a tumor type in which acquired inactivation of SMARCB1 and development of AT/RT features may occur and lead to clinical progression. In contrast, the PLAGL2 and PLAGL1 amplified cases showed either embryonal histology or contained an embryonal component with a significant degree of desmin staining, which could also serve to raise consideration for a PLAG entity when present. Continued compilation of associated clinical data and histopathologic findings will be critical for understanding emerging entities with PLAG-family genetic alterations.

Hyperoxia exposure induces ferroptosis and apoptosis by downregulating PLAGL2 and repressing HIF-1α/VEGF signaling pathway in newborn alveolar typeII epithelial cell.

BACKGROUD: Bronchopulmonary dysplasia (BPD) is one of the most important complications plaguing neonates and can lead to a variety of sequelae. the ability of the HIF-1α/VEGF signaling pathway to promote angiogenesis has an important role in neonatal lung development. METHOD: Newborn rats were exposed to 85% oxygen. The effects of hyperoxia exposure on Pleomorphic Adenoma Gene like-2 (PLAGL2) and the HIF-1α/VEGF pathway in rats lung tissue were assessed through immunofluorescence and Western Blot analysis. In cell experiments, PLAGL2 was upregulated, and the effects of hyperoxia and PLAGL2 on cell viability were evaluated using scratch assays, CCK-8 assays, and EDU staining. The role of upregulated PLAGL2 in the HIF-1α/VEGF pathway was determined by Western Blot and RT-PCR. Apoptosis and ferroptosis effects were determined through flow cytometry and viability assays. RESULTS: Compared with the control group, the expression levels of PLAGL2, HIF-1α, VEGF, and SPC in lung tissues after 3, 7, and 14 days of hyperoxia exposure were all decreased. Furthermore, hyperoxia also inhibited the proliferation and motility of type II alveolar epithelial cells (AECII) and induced apoptosis in AECII. Upregulation of PLAGL2 restored the proliferation and motility of AECII and suppressed cell apoptosis and ferroptosis, while the HIF-1α/VEGF signaling pathway was also revived. CONCLUSIONS: We confirmed the positive role of PLAGL2 and HIF-1α/VEGF signaling pathway in promoting BPD in hyperoxia conditions, and provided a promising therapeutic targets.

A Novel CRISPR/Cas9-mediated Mouse Model of Colon Carcinogenesis.

BACKGROUND & AIMS: Human sporadic colorectal cancer (CRC) results from a multistep pathway with sequential acquisition of specific genetic mutations in the colorectal epithelium. Modeling CRC in vivo is critical for understanding the tumor microenvironment. To accurately recapitulate human CRC pathogenesis, mouse models must include these multi-step genetic abnormalities. The aim of this study was to generate a sporadic CRC model that more closely mimics this multi-step process and to use this model to study the role of a novel Let7 target PLAGL2 in CRC pathogenesis. METHODS: We generated a CRISPR/Cas9 somatic mutagenesis mouse model that is inducible and multiplexed for simultaneous inactivation of multiple genes involved in CRC pathogenesis. We used both a doxycycline-inducible transcriptional activator and a doxycycline-inactivated transcriptional repressor to achieve tight, non-leaky expression of the Cas9 nickase. This mouse has transgenic expression of multiple guide RNAs to induce sporadic inactivation in the gut epithelium of 4 tumor suppressor genes commonly mutated in CRC, Apc, Pten, Smad4, and Trp53. These were crossed to Vil-LCL-PLAGL2 mice, which have Cre-inducible overexpression of PLAGL2 in the gut epithelium. RESULTS: These mice exhibited random somatic mutations in all 4 targeted tumor suppressor genes, resulting in multiple adenomas and adenocarcinomas in the small bowel and colon. Crosses with Vil-LCL-PLAGL2 mice demonstrated that gut-specific PLAGL2 overexpression increased colon tumor growth. CONCLUSIONS: This conditional model represents a new CRISPR/Cas9-mediated mouse model of colorectal carcinogenesis. These mice can be used to investigate the role of novel, previously uncharacterized genes in CRC, in the context of multiple commonly mutated tumor suppressor genes and thus more closely mimic human CRC pathogenesis.

Hemiprotonic ph-ph+ with two targets inhibits metastatic breast cancer and concurrent candidiasis.

Concurrent infection in breast cancer patients is the direct cause of the high mortality rate of the disease. However, there is no available method to increase the survival rate until now. To address the problem, we propose one drug with two target strategy to treat the refractory disease. A small chemical, ph-ph+, was attempted to be used in the study to explore the feasibility of the approach in anticancer and antifungus at the same time. The results showed that ph-ph+ could prevent the proliferation and metastasis of breast cancer cells, and kill C. albicans simultaneously. The molecular mechanism was associated with the activation of an evolutionarily conserved protease CLpP in the cancer and C. albicans cells. Also, the signaling pathway mediated by PLAGL2 that highly expressed in cancer cells participated in preventing cell metastasis and inducing apoptosis of ph-ph+. The one drug with dual targets inhibited the growth and metastasis of the cancer cells, and meanwhile eliminated C. albicans in tissues in the experimental animals. The results suggested that ph-ph+ with dual targets of CLpP and PLAGL2 would be a feasible approach to prolong the survival rate in patients with metastatic breast cancer and pathogenic infection.

Inhibiting the m6A Reader IGF2BP3 Suppresses Ovarian Cancer Cell Growth via Regulating PLAGL2 mRNA Stabilization.

Background: The oncogene IGF2 mRNA binding protein 3 (IGF2BP3) could function as an m6A reader in stabilizing many tumor-associated genes' mRNAs. However, the relevant oncogenic mechanism by which IGF2BP3 promotes ovarian cancer growth is largely unknown. Methods: The IGF2BP3 expression in ovarian cancer was identified by retrieving the datasets from The Cancer Genome Atlas (TCGA). GEO datasets evaluated the relevant signaling pathways in IGF2BP3 knockdown in ovarian cancer cells. IGF2BP3 positive correlation gene in TCGA was calculated. MTS proliferation assay was identified in IGF2BP3 knockdown and rescued by PLAG1 like zinc finger 2 (PLAGL2) overexpression in ES-2 and SKOV3 cells. Bioinformatic analysis and RIP-qPCR were predicted and identified the IGF2BP3 binding site and PLAGL2 mRNA stability. The animal experiment identified IGF2BP3 proliferation inhibition. Results: IGF2BP3 was upregulated in ovarian cancer tissue and cells. The depletion of IGF2BP3 in ovarian cancer cells leads to an enhancement of the pathway involved in cellular proliferation and mRNA stability. IGF2BP3 positive correlation suppressed pro-proliferation gene PLAGL2. IGF2BP3 knockdown suppressed ovarian cancer cell proliferation and was rescued by PLAGL2 overexpression. Luciferase reporter assay confirmed that IGF2BP3 could bind to 3'-UTR of PLAGL2 to maintain the mRNA stability. Further, in in vivo experiments, IGF2BP3 knockdown suppressed ovarian cancer cell proliferation via inhibiting PLAGL2 expression. Conclusion: All of these indicate that PLAGL2 mediates the main function of IGF2BP3 knockdown on ovarian cancer proliferation inhibition through mRNA stability regulation.

The oncogenic function of PLAGL2 is mediated via ASCL2 and IGF2 and a Wnt-independent mechanism in colorectal cancer.

Colorectal cancer (CRC) tumorigenesis and progression are linked to common oncogenic mutations, especially in the tumor suppressor APC, whose loss triggers the deregulation of TCF4/ß-Catenin activity. CRC tumorigenesis is also driven by multiple epimutational modifiers such as transcriptional regulators. We describe the common (and near-universal) activation of the zinc finger transcription factor and Let-7 target PLAGL2 in CRC and find that it is a key driver of intestinal epithelial transformation. PLAGL2 drives proliferation, cell cycle progression, and anchorage-independent growth in CRC cell lines and nontransformed intestinal cells. Investigating effects of PLAGL2 on downstream pathways revealed very modest effects on canonical Wnt signaling. Alternatively, we find pronounced effects on the direct PLAGL2 target genes IGF2, a fetal growth factor, and ASCL2, an intestinal stem cell-specific bHLH transcription factor. Inactivation of PLAGL2 in CRC cell lines has pronounced effects on ASCL2 reporter activity. Furthermore, ASCL2 expression can partially rescue deficits of proliferation and cell cycle progression caused by depletion of PLAGL2 in CRC cell lines. Thus, the oncogenic effects of PLAGL2 appear to be mediated via core stem cell and onco-fetal pathways, with minimal effects on downstream Wnt signaling.NEW & NOTEWORTHY A Let-7 target called PLAGL2 drives oncogenic transformation via Wnt-independent pathways. This work illustrates the robust effects of this zinc finger transcription factor in colorectal cancer (CRC) cell lines and nontransformed intestinal epithelium, with effects mediated, in part, via the direct target genes ASCL2 and IGF2. This has implications for the role of PLAGL2 in activation of onco-fetal and onco-stem cell pathways, contributing to immature and highly proliferative phenotypes in CRC.

PLAGL2 induces nucleus pulposus cell apoptosis via regulating RASSF5 expression and thus accelerates intervertebral disc degeneration.

Excessive apoptosis of nucleus pulposus (NP) cells is the main pathological change in intervertebral disc degeneration (IVDD) progression. Pleomorphic adenoma gene like-2 (PLAGL2) plays a key role in cell apoptosis, however, the effect of PLAGL2 on IVDD has not been clarified yet. In this study, we established mouse IVDD models via the annulus fibrosis needle puncture, TUNEL and safranin O staining were used to verify the successful establishment of IVDD models, and PLAGL2 expression was detected in disc tissues. Then, NP cells isolated from disc tissues were used to construct PLAGL2 knockdown cells. PLAGL2 expression in NP cells was analyzed with qRT-PCR and Western blot. The impact of PLAGL2 on the viability, apoptosis, and mitochondria function of NP cells was evaluated by MTT assay, TUNEL, JC1 staining, and flow cytometry assay. Additionally, the regulatory mechanism of PLAGL2 was further assessed. We found that PLAGL2 was upregulated in IVDD disc tissues and serum deprivation (SD)-stimulated NP cells. PLAGL2 knockdown inhibited apoptosis and mitochondria damage in NP cells. Moreover, knockdown of PLAGL2 downregulated the expression of downstream apoptosis-related factors RASSF5, Nip3, and p73. Mechanically, PLAGL2 transcriptionally activated RASSF5 via binding to its promoter. In general, our findings indicate that PLAGL2 induces apoptosis in NP cells and aggravates IVDD progression. This study provides a promising therapeutic target for IVDD treatment.

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.

Long non-coding RNA LGALS8-AS1 facilitates PLAGL2-mediated malignant phenotypes in gastric cancer.

BACKGROUND: Great progress has been made in studying the function of long non-coding RNA (lncRNA) in various tumors, including gastric cancer (GC). However, there are still numerous lncRNAs that have not yet been studied and explored for their roles in GC, and their important functions need to be further revealed. METHODS: Through analyzing The Cancer Genome Atlas (TCGA) database combined with bioinformatics survival tools, a novel GC-related lncRNA LGALS8-AS1 was identified. A quantitative real-time polymerase chain reaction and a series of in vitro or in vivo cell functional experiments were performed to determine the expression and the role of LGALS8-AS1/miR-138-5p/PLAGL2 in GC. RESULTS: LGALS8-AS1 was remarkably upregulated and correlated with the unfavorable prognosis in GC. Higher expression of LGALS8-AS1 was positively associated with higher lymph node metastasis rate, as well as larger tumor size. In addition, a series of cell functional experiments revealed that LGALS8-AS1 could facilitate GC cell proliferation, migration and metastasis in vitro or in vivo. A deeper mechanism exploration revealed that LGALS8-AS1 could function as the miR-138-5p molecular sponge and upregulate the PLAGL2 expression, thereby promoting the cell proliferation, migration and metastasis in GC. CONCLUSIONS: In brief, we revealed the tumor promoting role of the LGALS8-AS1/miR-138-5p/PLAGL2 molecular signaling axis in GC, and our findings provide enlightenment for further understanding of the mechanism of tumorigenesis and development of GC, making LGALS8-AS1 a possible new diagnostic or therapeutic target for GC.

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.

Amplification of the PLAG-family genes-PLAGL1 and PLAGL2-is a key feature of the novel tumor type CNS embryonal tumor with PLAGL amplification.

Pediatric central nervous system (CNS) tumors represent the most common cause of cancer-related death in children aged 0-14 years. They differ from their adult counterparts, showing extensive clinical and molecular heterogeneity as well as a challenging histopathological spectrum that often impairs accurate diagnosis. Here, we use DNA methylation-based CNS tumor classification in combination with copy number, RNA-seq, and ChIP-seq analysis to characterize a newly identified CNS tumor type. In addition, we report histology, patient characteristics, and survival data in this tumor type. We describe a biologically distinct pediatric CNS tumor type (n = 31 cases) that is characterized by focal high-level amplification and resultant overexpression of either PLAGL1 or PLAGL2, and an absence of recurrent genetic alterations characteristic of other pediatric CNS tumor types. Both genes act as transcription factors for a regulatory subset of imprinted genes (IGs), components of the Wnt/ß-Catenin pathway, and the potential drug targets RET and CYP2W1, which are also specifically overexpressed in this tumor type. A derived PLAGL-specific gene expression signature indicates dysregulation of imprinting control and differentiation/development. These tumors occurred throughout the neuroaxis including the cerebral hemispheres, cerebellum, and brainstem, and were predominantly composed of primitive embryonal-like cells lacking robust expression of markers of glial or neuronal differentiation (e.g., GFAP, OLIG2, and synaptophysin). Tumors with PLAGL1 amplification were typically diagnosed during adolescence (median age 10.5 years), whereas those with PLAGL2 amplification were diagnosed during early childhood (median age 2 years). The 10-year overall survival was 66% for PLAGL1-amplified tumors, 25% for PLAGL2-amplified tumors, 18% for male patients, and 82% for female patients. In summary, we describe a new type of biologically distinct CNS tumor characterized by PLAGL1/2 amplification that occurs predominantly in infants and toddlers (PLAGL2) or adolescents (PLAGL1) which we consider best classified as a CNS embryonal tumor and which is associated with intermediate survival. The cell of origin and optimal treatment strategies remain to be defined.

PLAGL2 increases adriamycin resistance and EMT in breast cancer cells by activating the Wnt pathway.

BACKGROUND: Adriamycin (ADR) is an effective treatment for breast cancer; nevertheless, it is often linked with acquired resistance in breast cancer cells, reducing ADR's therapeutic efficacy and increasing the risk of recurrence and poor prognosis. It has been revealed that the zinc-finger transcription factor pleomorphic adenoma gene like-2 (PLAGL2) is required for epithelial to mesenchymal transition (EMT) in cancer cells. Recent data indicates that PLAGL2 is also involved in regulating chemotherapeutic drug resistance, albeit the exact mechanism by which this happens remains unknown. OBJECTIVE: This study examines the effect of PLAGL2 on adriamycin resistance and EMT in breast cancer cells. METHODS: The small interfering RNA (siRNA) targeting PLAGL2 was transfected to breast cancer cells to alter PLAGL2 expression. Cell counting kit-8 (CCK-8) and colony formation assay detected cell growth and proliferation rate. Moreover, wound-healing and transwell assays were conducted to evaluate migration and invasion. Western blot (WB) checked the apoptosis and EMT-associated proteins. RESULTS: PLAGL2 expression is associated with breast cancer cells' acquired resistance to ADR in this investigation. Additionally, deletion of PLAGL2 was associated with enhanced sensitivity to ADR, reduced proliferation, migration, and invasion capabilities, increased E-cadherin levels, and reduced Wnt6, ß-catenin, and DVL1 levels in ADR-resistant breast cancer cells (MCF-7/ADR and MDA-MB-231/ADR cells). PLAGL2 could bind to the promoter region of Wnt6 and promote its expression. Additionally, the results of this research established that Wnt signaling is implicated in breast cancer cells' resistance to ADR since BML-284, a Wnt signaling activator partly restored the sensitivity of MCF-7/ADR and MDA-MB-231/ADR cells to ADR. CONCLUSION: PLAGL2 promotes adriamycin resistance and cell aggressiveness in breast cancer cells via activating the Wnt signaling pathway.

PLAGL2 Promotes the Proliferation and Migration of Diffuse Large B-cell Lymphoma Cells via Wnt/ß-catenin Pathway.

OBJECTIVE: Pleomorphic adenoma gene like-2 (PLAGL2) belongs to PLAG protein family and functions as a zinc finger transcriptional factor to participate in the cellular processes, including cell transformation, migration, and apoptosis. Increasing evidence has shown the oncogenic role of PLAGL2 in various cancers, while the potential molecular mechanism and biology roles of PLAGL2 in diffuse large B-cell lymphoma (DLBCL) are still unclear. METHODS: Expression of PLAGL2 was found to be elevated in DLBCL cells. Functional assays showed that silence of PLAGL2 suppressed cell proliferation and reduced the cell migration and invasion in DLBCL. The cell proliferation and metastasis in DLBCL were promoted by over-expression of PLAGL2. Moreover, the protein expression of E-cadherin was increased, while the protein expressions of N-cadherin and vimentin were decreased in DLBCL cells by knockdown of PLAGL2. However, over-expression of PLAGL2 promoted epithelial to mesenchymal transition (EMT) of DLBCL through down-regulation of E-cadherin, and up-regulations of N-cadherin and vimentin. RESULTS: Over-expression of PLAGL2 up-regulated ß-catenin and c-myc, while down-regulated axis inhibition protein 2 (AXIN2) and adenomatous polyposis coli (APC) in DLBCL. Knockdown of PLAGL2 suppressed the activation of Wnt/ß-catenin pathway in DLBCL through downregulating ß-catenin and c-myc but upregulating AXIN2 and APC. Xenograft model also demonstrated that interference of PLAGL2 repressed the in vivo tumor growth of DLBCL. CONCLUSION: In conclusion, PLAGL2 promoted the malignancy of DLBCL through activation of Wnt/ß-catenin pathway.

Overexpression of GATA5 Inhibits Prostate Cancer Progression by Regulating PLAGL2 via the FAK/PI3K/AKT Pathway.

BACKGROUND: Prostate cancer (PCa) is a malignancy with high incidence and the principal cause of cancer deaths in men. GATA binding protein 5 (GATA5) belongs to the GATA gene family. GATA5 has a close association with carcinogenesis, but the role of GATA5 in PCa remains poorly understood. The aim of our present study was to probe into the effect of GATA5 on PCa progression and to elucidate the involved mechanism. METHODS: The expression of GATA5 was detected in both PCa samples and PCa cell lines. GATA5 overexpression, PLAGL2 knockdown, and overexpression cell models were generated, then Western blotting experiments were utilized to validate the efficiency of transfection. The effects of GATA5 on PCa cell proliferation, metastasis, apoptosis, cell cycle progression, and EMT were detected in vitro or in vivo. Furthermore, the mechanism by which GATA5 inhibits prostate cancer progression through regulating PLAGL2 via the FAK/PI3K/AKT pathway was also explored. RESULTS: GATA5 expression was downregulated in PCa samples and cell lines. GATA5 overexpression inhibited PCa cell proliferation and metastasis but increased the rate of apoptosis. In addition, we confirmed that GATA5 inhibited prostate cancer progression, including EMT, by regulating PLAGL2 via the FAK/PI3K/AKT pathway. CONCLUSION: We demonstrated that GATA5, as a tumor suppressor in PCa, inhibits PCa progression by regulating PLAGL2. These results showed that the GATA5/PLAGL2/FAK/PI3K/AKT pathway may become a new therapeutic direction for the treatment of PCa.

Functional rejuvenation of aged neural stem cells by Plagl2 and anti-Dyrk1a activity.

The regenerative potential of neural stem cells (NSCs) declines during aging, leading to cognitive dysfunctions. This decline involves up-regulation of senescence-associated genes, but inactivation of such genes failed to reverse aging of hippocampal NSCs. Because many genes are up-regulated or down-regulated during aging, manipulation of single genes would be insufficient to reverse aging. Here we searched for a gene combination that can rejuvenate NSCs in the aged mouse brain from nuclear factors differentially expressed between embryonic and adult NSCs and their modulators. We found that a combination of inducing the zinc finger transcription factor gene Plagl2 and inhibiting Dyrk1a, a gene associated with Down syndrome (a genetic disorder known to accelerate aging), rejuvenated aged hippocampal NSCs, which already lost proliferative and neurogenic potential. Such rejuvenated NSCs proliferated and produced new neurons continuously at the level observed in juvenile hippocampi, leading to improved cognition. Epigenome, transcriptome, and live-imaging analyses indicated that this gene combination induces up-regulation of embryo-associated genes and down-regulation of age-associated genes by changing their chromatin accessibility, thereby rejuvenating aged dormant NSCs to function like juvenile active NSCs. Thus, aging of NSCs can be reversed to induce functional neurogenesis continuously, offering a way to treat age-related neurological disorders.

LncRNA HCP5 acts as a miR-128-3p sponge to promote the progression of multiple myeloma through activating Wnt/ß-catenin/cyclin D1 signaling via PLAGL2.

BACKGROUND: Although long non-coding RNA (lncRNA) HCP plays essential roles in human cancers, its function and mechanism in multiple myeloma (MM) have not crystallized. METHODS: HCP5 level in MM was assessed through qRT-PCR. A series of functional investigations were conducted to evaluate the influences of HCP5 on proliferation and apoptosis. Bioinformatics analysis and RIP/RNA pull-down assays were carried out to determine the relationships among HCP5, miR-128-3p, and PLAGL2. Relative protein level was determined through Western blot. A xenograft tumor model was applied for validating the roles of HCP5/miR-128-3p/PLAGL2 axis in vivo. RESULTS: HCP5 was significantly increased in MM. HCP5 knockdown effectively thwarted the proliferative rate and cell cycle of MM cell lines and suppressed tumor growth. HCP5 regulated PLAGL2 expression by sponging miR-128-3p. PLAGL2 overexpression effectively rescued cells from influences by sh-HCP5 on cell proliferative and apoptotic rates. Additionally, HCP5 knockdown significantly inhibited Wnt/ß-catenin/cyclin D1 signaling, and these effects were eliminated by PLAGL2 overexpression. CONCLUSION: Our study revealed that HCP5/miR-128-3p/PLAGL2 is closely correlated to MM development by modulating Wnt/ß-catenin/cyclin D1 signaling. HCP5 promoted cell proliferation and tumor formation of MM cells by activating the Wnt/ß-catenin/CCND1 signaling pathway by sponging miR-128-3p to increase PLAGL2 expression.

Selenium sulfide disrupts the PLAGL2/C-MET/STAT3-induced resistance against mitochondrial apoptosis in hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. Overexpression of pleomorphic adenoma gene like-2 (PLAGL2) is associated with tumorigenesis. However, its function in HCC is unclear, and there are currently no anti-HCC drugs that target PLAGL2. Drug repositioning may facilitate the development of PLAGL2-targeted drug candidates. METHODS: The expression of PLAGL2 in HCC clinical tissue samples and HCC cell lines was analyzed by western blotting. The constructed HCC cell models were used to confirm the underlying function of PLAGL2 as a therapeutic target. Multiple in vitro and in vivo assays were conducted to determine the anti-proliferative and apoptosis-inducing effects of selenium sulfide (SeS2 ), which is clinically used for the treatment of seborrheic dermatitis and tinea versicolor. RESULTS: PLAGL2 expression was higher in HCC tumor tissues than in normal adjacent tissues. Its overexpression promoted the resistance of HCC cells of mitochondrial apoptosis through the regulation of the downstream C-MET/STAT3 signaling axis. SeS2 exerted significant anti-proliferative and apoptosis-inducing effects on HCC cells in a PLAGL2-dependent manner. Mechanistically, SeS2 suppressed C-MET/STAT3, AKT/mTOR, and MAPK signaling and triggered Bcl-2/Cyto C/Caspase-mediated intrinsic mitochondrial apoptosis both in vitro and in vivo. CONCLUSIONS: Our data reveal an important role of PLAGL2 in apoptosis resistance in HCC and highlight the potential of using SeS2 as a PLAGL2 inhibitor in patients with HCC.

LncRNA ARAP1-AS1 aggravates the malignant phenotypes of ovarian cancer cells through sponging miR-4735-3p to enhance PLAGL2 expression.

Ovarian cancer is one of the leading lethal gynecological cancers, causing serious harm to the health of female populations. Growing studies emphasize that lncRNAs serve as significant regulators in the tumorigenesis and evolution of numerous malignancies, including ovarian cancer. Recently, the oncogenic activity of lncRNA ARAP1-AS1 has been justified in a variety of cancers. However, the potential function of ARAP1-AS1 in ovarian cancer development is still unclear. Herein, we firstly revealed the expression profile of ARAP1-AS1 in ovarian cancer. Compared to normal samples and cells, upregulation of ARAP1-AS1 was observed in tissues and cells of ovarian cancer. Therewith, it was disclosed that knockdown of ARAP1-AS1 alleviated the carcinogenicity of ovarian cancer cells. Besides, our findings delineated that ARAP1-AS1 silence inhibited the expression of oncogene PLAGL2. Considering that ARAP1-AS1 was principally expressed in the the cytoplasm of ovarian cancer cells, we speculated that ARAP1-AS1 facilitated ovarian cancer progression via functioning as a ceRNA. Further investigations indicated that ARAP1-AS1 promoted PLAGL2 expression by competitively binding with miR-4735-3p. Of note, ARAP1-AS1 contributed to the malignant phenotypes of ovarian cancer cells through modulation of miR-4735-3p/PLAGL2 axis, revealing ARAP1-AS1 as a promising therapeutic target for ovarian cancer patients.

Long noncoding RNA ILF3-AS1 aggravates papillary thyroid carcinoma progression via regulating the miR-4306/PLAGL2 axis.

BACKGROUND: It have been proven that long non-coding RNAs (lncRNAs) serve as regulators in carcinogenesis. Interleukin enhancer binding factor 3 antisense RNA 1 (ILF3-AS1) has been illuminated as a prognostic factor in some cancers. Nevertheless, its expression pattern and possible functions in papillary thyroid carcinoma (PTC) have not been studied. METHODS: The expression of ILF3-AS1 was measured by RT-qPCR and ISH. Colony formation assay and EdU assay were used to probe cell proliferation. TUNEL assay was used for analysis of cell apoptosis. Immunofluorescence and western blot were conducted to evaluate the expression change of E-cadherin and N-cadherin. The RNA interaction was demonstrated by mechanism experiments, including pull down assay and dual luciferase reporter assay. RESULTS: ILF3-AS1 expression was evidently upregulated in PTC cell lines. ILF3-AS1 knockdown restrained the proliferation, migration and invasion of PTC cells. Mechanical investigation revealed that miR-4306 could interact with ILF3-AS1. PLAGL2 was a downstream target of miR-4306. The effects of ILF3-AS1 knockdown on the cellular processes were abrogated by miR-4306 downregulation or pleiomorphic adenoma gene-like 2 (PLAGL2) overexpression. CONCLUSION: ILF3-AS1 plays tumor-promoting role in PTC via targeting miR-4306/PLAGL2 axis.

Long non-coding RNA MAPKAPK5-AS1/PLAGL2/HIF-1α signaling loop promotes hepatocellular carcinoma progression.

BACKGROUND: Long non-coding RNAs (lncRNAs) are widely involved in human cancers' progression by regulating tumor cells' various malignant behaviors. MAPKAPK5-AS1 has been recognized as an oncogene in colorectal cancer. However, the biological role of MAPKAPK5-AS1 in hepatocellular carcinoma (HCC) has not been explored. METHODS: Quantitative real-time PCR was performed to detect the level of MAPKAPK5-AS1 in HCC tissues and cell lines. The effects of MAPKAPK5-AS1 on tumor growth and metastasis were assessed via in vitro experiments, including MTT, colony formation, EdU, flow cytometry, transwell assays, and nude mice models. The western blotting analysis was carried out to determine epithelial-mesenchymal transition (EMT) markers and AKT signaling. The interaction between MAPKAPK5-AS1, miR-154-5p, and PLAGL2 were explored by luciferase reporter assay and RNA immunoprecipitation. The regulatory effect of HIF-1α on MAPKAPK5-AS1 was evaluated by chromatin immunoprecipitation. RESULTS: MAPKAPK5-AS1 expression was significantly elevated in HCC, and its overexpression associated with malignant clinical features and reduced survival. Functionally, MAPKAPK5-AS1 knockdown repressed the proliferation, mobility, and EMT of HCC cells and induced apoptosis. Ectopic expression of MAPKAPK5-AS1 contributed to HCC cell proliferation and invasion in vitro. Furthermore, MAPKAPK5-AS1 silencing suppressed, while MAPKAPK5-AS1 overexpression enhanced HCC growth and lung metastasis in vivo. Mechanistically, MAPKAPK5-AS1 upregulated PLAG1 like zinc finger 2 (PLAGL2) expression by acting as an endogenous competing RNA (ceRNA) to sponge miR-154-5p, thereby activating EGFR/AKT signaling. Importantly, rescue experiments demonstrated that the miR-154-5p/PLAGL2 axis mediated the function of MAPKAPK5-AS1 in HCC cells. Interestingly, we found that hypoxia-inducible factor 1α (HIF-1α), a transcript factor, could directly bind to the promoter to activate MAPKAPK5-AS1 transcription. MAPKAPK5-AS1 regulated HIF-1α expression through PLAGL2 to form a hypoxia-mediated MAPKAPK5-AS1/PLAGL2/HIF-1α signaling loop in HCC. CONCLUSIONS: Our results reveal a MAPKAPK5-AS1/PLAGL2/HIF-1α signaling loop in HCC progression and suggest that MAPKAPK5-AS1 could be a potential novel therapeutic target of HCC.