STAT3 promotes tumour progression in glioma by inducing FOXP1 transcription

Gene regulatory network topology governs resistance and treatment escape in glioma stem-like cells

Poor prognosis and drug resistance in glioblastoma (GBM) can result from cellular heterogeneity and treatment-induced shifts in phenotypic states of tumor cells, including dedifferentiation into glioma stem-like cells (GSCs). This rare tumorigenic cell subpopulation resists temozolomide, undergoes proneural-to-mesenchymal transition (PMT) to evade therapy, and drives recurrence. Through inference of transcriptional regulatory networks (TRNs) of patient-derived GSCs (PD-GSCs) at single-cell resolution, we demonstrate how the topology of transcription factor interaction networks drives distinct trajectories of cell-state transitions in PD-GSCs resistant or susceptible to cytotoxic drug treatment. By experimentally testing predictions based on TRN simulations, we show that drug treatment drives surviving PD-GSCs along a trajectory of intermediate states, exposing vulnerability to potentiated killing by siRNA or a second drug targeting treatment-induced transcriptional programs governing nongenetic cell plasticity. Our findings demonstrate an approach to uncover TRN topology and use it to rationally predict combinatorial treatments that disrupt acquired resistance in GBM.

YTHDF1 promotes the viability and self‑renewal of glioma stem cells by enhancing LINC00900 stability

YTHDF1, an N6‑methyladenosine (m6A)‑binding protein, is significantly upregulated in glioma tissues. The present study investigated the molecular mechanism underlying the regulatory effects of YTHDF1 on the viability, invasion and self‑renewal of glioma stem cells (GSCs). Glioma and normal brain tissues were collected, and reverse transcription‑quantitative PCR and western blotting were used to measure the gene and protein expression levels, respectively. Methylated RNA immunoprecipitation‑PCR was used to assess the m6A modification level of the target gene. Subsequently GSCs were induced, and YTHDF1 and LINC00900 gene regulation was carried out using lentiviral infection. The viability, invasion and self‑renewal of GSCs were assessed by Cell Counting Kit‑8, Transwell and sphere formation assays, respectively. Binding between YTHDF1 and LINC00900 was verified by RNA immunoprecipitation and RNA pull‑down assays. The targeted binding of microRNA (miR)‑1205 to the LINC00900/STAT3 3'‑UTR was verified using a luciferase reporter assay. The results revealed that YTHDF1 and LINC00900 expression levels were significantly upregulated in glioma tissues, and a high m6A modification level in LINC00900 transcripts was detected in glioma tissues. Overexpression of YTHDF1 promoted GSC viability, invasion and self‑renewal, whereas knockdown of YTHDF1 had the opposite effects. In addition, YTHDF1 maintained the stability of LINC00900 and upregulated its expression through binding to it, thereby promoting GSC viability, invasion and self‑renewal. Furthermore, LINC00900 promoted GSC viability, invasion, self‑renewal and tumor growth by regulating the miR‑1205/STAT3 axis. In conclusion, YTHDF1 promotes GSC viability and self‑renewal by regulating the LINC00900/miR‑1205/STAT3 axis.

Gene regulatory network topology governs resistance and treatment escape in glioma stem-like cells

Poor prognosis and drug resistance in glioblastoma (GBM) can result from cellular heterogeneity and treatment-induced shifts in phenotypic states of tumor cells, including dedifferentiation into glioma stem-like cells (GSCs). This rare tumorigenic cell subpopulation resists temozolomide, undergoes proneural-to-mesenchymal transition (PMT) to evade therapy, and drives recurrence. Through inference of transcriptional regulatory networks (TRNs) of patient-derived GSCs (PD-GSCs) at single-cell resolution, we demonstrate how the topology of transcription factor interaction networks drives distinct trajectories of cell state transitions in PD-GSCs resistant or susceptible to cytotoxic drug treatment. By experimentally testing predictions based on TRN simulations, we show that drug treatment drives surviving PD-GSCs along a trajectory of intermediate states, exposing vulnerability to potentiated killing by siRNA or a second drug targeting treatment-induced transcriptional programs governing non-genetic cell plasticity. Our findings demonstrate an approach to uncover TRN topology and use it to rationally predict combinatorial treatments that disrupts acquired resistance in GBM.

Identification of FOXP1 as a favorable prognostic biomarker and tumor suppressor in intrahepatic cholangiocarcinoma

BACKGROUND

Forkhead-box protein P1 (FOXP1) has been proposed to have both oncogenic and tumor-suppressive properties, depending on tumor heterogeneity. However, the role of FOXP1 in intrahepatic cholangiocarcinoma (ICC) has not been previously reported.

METHODS

Immunohistochemistry was performed to detect FOXP1 expression in ICC and normal liver tissues. The relationship between FOXP1 levels and the clinicopathological characteristics of patients with ICC was evaluated. Finally, in vitro and in vivo experiments were conducted to examine the regulatory role of FOXP1 in ICC cells.

RESULTS

FOXP1 was significantly downregulated in the ICC compared to their peritumoral tissues (p < 0.01). The positive rates of FOXP1 were significantly lower in patients with poor differentiation, lymph node metastasis, invasion into surrounding organs, and advanced stages (p < 0.05). Notably, patients with FOXP1 positivity had better outcomes (overall survival) than those with FOXP1 negativity (p < 0.05), as revealed by Kaplan-Meier survival analysis. Moreover, Cox multivariate analysis showed that negative FOXP1 expression, advanced TNM stages, invasion, and lymph node metastasis were independent prognostic risk factors in patients with ICC. Lastly, overexpression of FOXP1 inhibited the proliferation, migration, and invasion of ICC cells and promoted apoptosis, whereas knockdown of FOXP1 had the opposite role.

CONCLUSION

Our findings suggest that FOXP1 may serve as a novel outcome predictor for ICC as well as a tumor suppressor that may contribute to cancer treatment.

The function of Foxp1 represses β-adrenergic receptor transcription in the occurrence and development of bladder cancer through STAT3 activity

Bladder cancer is a common malignant tumor. FOXP1 has been found to be abnormally expressed in tumors such as renal cell carcinoma and endometrial cancer. Here, this investigated the biological roles of Foxp1 in the occurrence and development of bladder cancer. Patients with bladder cancer were obtained from China-Japan Friendship Hospital. Bladder cancer cell lines (5637, UMUC3, J82, and T24 cell) were used in this experiment. Foxp1 mRNA and protein expression levels in patients with bladder cancer were increased, compared with paracancerous tissue (normal). OS and DFS of Foxp1 low expression in patients with bladder cancer were higher than those of Foxp1 high expression. Foxp1 promoted bladder cancer cell growth in vitro model. Foxp1 increased the Warburg effect of bladder cancer. Foxp1 suppressed β-adrenoceptor (β-AR) expression in vitro model. ChIP-seq showed that Foxp1 binding site (E1, TTATTTAT) was detected at -2,251 bp upstream of the β-AR promoter. β-AR Reduced the effects of Foxp1 on cell growth in vitro model. β-AR reduced the effects of Foxp1 on the Warburg effect in vitro model by STAT3 activity. Taken together, our findings reveal that Foxp1 promoted the occurrence and development of bladder cancer through the Warburg effect by the activation of STAT3 activity and repressing β-AR transcription, and which might serve as an important clue for its targeting and treatment of bladder cancer.

KAT6B May Be Applied as a Potential Therapeutic Target for Glioma

Glioma is a prevalent malignancy among brain tumors with high modality and low prognosis. Ferroptosis has been identified to play a crucial role in the progression and treatment of cancers. KAT6B, as a histone acetyltransferase, is involved in multiple cancer development. However, the function of KAT6B in glioma is still elusive. Here, we aimed to evaluate the effect of KAT6B on ferroptosis in glioma cells and explored the potential mechanisms. We observed that the expression of KAT6B was enhanced in clinical glioma samples. The viability of glioma cells was repressed by erastin and the overexpression of KAT6B rescued the phenotype in the cells. Meanwhile, the apoptosis of glioma cells was induced by the treatment of erastin, while the overexpression of KAT6B blocked the effect in the cells. The levels of lipid ROS and iron were promoted by the treatment of erastin and the overexpression of KAT6B could reverse the effect in the cells. Mechanically, we identified that the expression of STAT3 was repressed by the KAT6B knockdown in glioma cells. The KAT6B was able to enrich on the promoter of STAT3 in glioma cells. Meanwhile, ChIP assay showed that the knockdown of KAT6B inhibited the enrichment of histone H3 lysine 23 acetylation (H3K23ac) and RNA polymerase II (RNA pol II) on STAT3 promoter in the cells. Depletion of STAT3 reversed KAT6B-regulated viability, apoptosis, and ferroptosis of glioma cells. Thus, we concluded that KAT6B contributes to glioma progression by repressing ferroptosis via epigenetically inducing STAT3.

Bioinformatics analysis reveals a stem cell-expressed circ-Serpine2-mediated miRNA-mRNA regulatory subnetwork in the malignant progression of glioma

Background

High-grade glioma has a poor prognosis, and GSCs can have pivotal roles in glioma pathology. This study investigated GSC exosome-containing circRNA mechanisms affecting the malignant progression of glioma.

Methods

In this study, we identified differentially expressed circRNAs and constructed a circRNA-miRNA-mRNA regulatory network through circRNA sequencing/bioinformatics analysis. Then, we identified circRNAs that were upregulated in GSC23 cells and employed them as downstream targets in subsequent investigations. Such investigations included downstream target knockout to assess any influence on A172 cell proliferation, invasion, migration and apoptosis. In addition, in vivo investigations using tumor-bearing animals evaluated the in vivo influences of the selected targets.

Results

This study identified circ-Serpine2/miR-124-3p/KIF20A as a regulatory pathway in glioma. Our in vitro analysis confirmed that circ-Serpine2 could upregulate KIF20A by sponging miR-124-3p, consequently promoting A172 cell proliferation, migration and invasion. Such a signaling channel could also inhibit glioma cell apoptosis. Additionally, our research indicated that circ-Serpine2 inhibited glioma apoptosis and promoted in vivo tumor progression.

Conclusion

Circ-Serpine2 exacerbated the malignant progression of glioma mediated by the miR-124-3p/KIF20A nexus, thus providing novel predictive/prognostic biomarkers and drug targets against glioma.

Identification of JAK2 and FOXM1 expression as novel candidate biomarkers for predicting the benefit of immunotherapy in lung squamous cell carcinoma

Background

Lung squamous cell carcinoma (LUSC) accounts for about 30% of all non-small cell lung cancers (NSCLC). However, only a small percentage of LUSC patients gain benefit from immune checkpoint inhibitors (ICIs).

Methods

This study analyzed LUSC patients from The Cancer Genome Atlas (TCGA), which were divided into 2 groups: PD-L1 high-expression/TMB-high (TPH) and PD-L1 low-expression/TMB-low (TPL) group based on programmed death-ligand 1 (PD-L1) expression and tumor mutational burden (TMB) status. The differences in tumor-infiltrating immune cells were estimated between the 2 groups. The overlap of differentially expressed genes and proteins (DEGs and DEPs) between 2 groups were used as candidate biomarkers. Kaplan-Meier curves were used to evaluate the association between risk score and overall survival (OS).

Results

More abundant immune infiltration fractions were found in TPH group. Janus kinase 2 (JAK2) and forkhead box protein M1 (FOXM1) were identified as DEGs between the TPH and TPL groups. Subsequently, we developed a risk score that combined the expression of JAK2 and FOXM1 in an effort to accurately determine the survival risk of LUSC patients. Patients with high-risk [hazard ratio (HR), median OS, 43.1 months 1.924; 95% confidence interval (CI): 1.256 to 2.945; P=0.002) had shorter survival than those with low-risk (median OS, 70.0 months). External data verification found that JAK2 and FOXM1 were significantly expressed at a higher level in the responders receiving immunotherapy (P=0.038 and P=0.009, respectively).

Conclusions

The expressions of JAK2 and FOXM1 can be used as novel candidate biomarkers for predicting the benefit of immunotherapy in LUSC.

Noncoding RNAs involved in the STAT3 pathway in glioma

Glioma is the most common malignant primary brain tumour in adults. Despite improvements in neurosurgery and radiotherapy, the prognosis of glioma patients remains poor. One of the main limitations is that there are no proper clinical therapeutic targets for glioma. Therefore, it is crucial to find one or more effective targets. Signal transducer and activator of transcription 3 (STAT3) is a member of the STAT family of genes. Abnormal expression of STAT3 is involved in the process of cell proliferation, migration, invasion, immunosuppression, angiogenesis, dryness maintenance, and resistance to radiotherapy and chemotherapy in glioma. Therefore, STAT3 has been considered an ideal therapeutic target in glioma. Noncoding RNAs (ncRNAs) are a group of genes with limited or no protein-coding capacity that can regulate gene expression at the epigenetic, transcriptional and posttranscriptional level. In this review, we summarized the ncRNAs that are correlated with the ectopic expression of STAT3 in glioma.

UBE2D3 Activates SHP-2 Ubiquitination to Promote Glycolysis and Proliferation of Glioma via Regulating STAT3 Signaling Pathway

Glioma is a primary brain cancer with high malignancy and morbidity. Current management for glioma cannot reach optimal remission. Therefore, it is necessary to find novel targets for glioma treatment. Ubiquitin-conjugating enzyme E2 D3 (UBE2D3) is involved in the pathogenesis of various kinds of cancer. However, its role in glioma remains unclear. Our study aims to explore the function and underlying mechanism of UBE2D3 in the development of glioma. By analysis with The Cancer Genome Atlas-Glioblastoma multiforme (TCGA-GBM) dataset, we found that UBE2D3 was highly expressed in glioma and it is positive correlation with glycolysis, apoptosis, and STAT3 pathway. Then, we explore the effects of UBE2D3 knockdown in the biological functions of glioma cell lines. Cell proliferation and apoptosis were estimated by cell counting kit-8 assay and flow cytometry. Extracellular acidification rate and oxygen consumption rate were estimated to determine the level of cell glycolysis. Xenograft experiments were performed to identify in vivo function of UBE2D3. The results showed that the inhibition of UBE2D3 could suppress the proliferation, glycolysis, and STAT3 phosphorylation of GBM both in vitro and in vivo. UBE2D3 could interact with SHP-2 and promoted its ubiquitination, which elevated the activation of STAT3 pathway. Overexpressed SHP-2 could reverse the effect of UBE2D3 and they shared contrary expression patterns in glioma and normal brain tissues. In summary, our study revealed that UBE2D3 could promote the ubiquitination of SHP-2, which activated STAT3 pathway and promoted glioma proliferation as well as glycolysis. UBE2D3 could be a potential target for glioma treatment.

MicroRNA-221 Upregulates the Expression of P-gp and Bcl-2 by Activating the Stat3 Pathway to Promote Doxorubicin Resistance in Osteosarcoma Cells

MicroRNA-221 (miRNA-221) is upregulated in several malignant tumors and is associated with poor patient prognosis. Therefore, the present study aimed to investigate the role and underlying mechanism of miRNA-221 in doxorubicin (DOX) resistance in osteosarcoma cells. We constructed DOX-resistant Saos-2/DOX cells and treated them with DOX. Cell viability was determined by performing a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cells were transfected with either miRNA-221 mimic or miRNA-221 inhibitor; quantitative (q)RT-PCR was performed to detect the expression of miRNA-221. Flow cytometry and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick-end labeling (TUNEL) staining were used to detect cell apoptosis. The immunofluorescence method was also used to detect cell signal transduction and activator of transcription 3 (Stat3) protein expression distribution. In addition, Western blotting was used to detect changes in the expression of each protein. We found that miRNA-221 was upregulated in Saos-2/DOX cells. Moreover, the miRNA-221 mimic induced DOX resistance in Saos-2 cells, whereas the miRNA-221 inhibitor enhanced DOX sensitivity in Saos-2/DOX cells. The miRNA-221 mimic upregulated the expression of phosphorylated-Stat3, P-glycoprotein (P-gp), and B-cell lymphoma-2 (Bcl-2) proteins in Saos-2 cells and induced the entry of Stat3 into the nucleus, whereas the miRNA-221 inhibitor exerted the opposite effect. Pretreatment with the Stat3 chemical inhibitor, STAT3-IN-3, significantly inhibited the upregulation of P-gp and Bcl-2 protein expression induced by the miRNA-221 mimic in Saos-2 cells; it also caused the Saos-2 cells to overcome DOX resistance induced by the miRNA-221 mimic. Thus, miRNA-221 increased the expression of P-gp and Bcl-2 by activating the Stat3 pathway to promote DOX resistance in osteosarcoma cells, indicating a potential use of miRNA-221 in osteosarcoma treatment.

Systemic brain tumor delivery of synthetic protein nanoparticles for glioblastoma therapy

Glioblastoma (GBM), the most aggressive form of brain cancer, has witnessed very little clinical progress over the last decades, in part, due to the absence of effective drug delivery strategies. Intravenous injection is the least invasive drug delivery route to the brain, but has been severely limited by the blood-brain barrier (BBB). Inspired by the capacity of natural proteins and viral particulates to cross the BBB, we engineered a synthetic protein nanoparticle (SPNP) based on polymerized human serum albumin (HSA) equipped with the cell-penetrating peptide iRGD. SPNPs containing siRNA against Signal Transducer and Activation of Transcription 3 factor (STAT3i) result in in vitro and in vivo downregulation of STAT3, a central hub associated with GBM progression. When combined with the standard of care, ionized radiation, STAT3i SPNPs result in tumor regression and long-term survival in 87.5% of GBM-bearing mice and prime the immune system to develop anti-GBM immunological memory.

PDIA3 Expression in Glioblastoma Modulates Macrophage/Microglia Pro-Tumor Activation

The glioblastoma (GB) microenvironment includes cells of the innate immune system identified as glioma-associated microglia/macrophages (GAMs) that are still poorly characterized. A potential role on the mechanisms regulating GAM activity might be played by the endoplasmic reticulum protein ERp57/PDIA3 (protein disulfide-isomerase A3), the modulation of which has been reported in a variety of cancers. Moreover, by using The Cancer Genome Atlas database, we found that overexpression of PDIA3 correlated with about 55% reduction of overall survival of glioma patients. Therefore, we analyzed the expression of ERp57/PDIA3 using specimens obtained after surgery from 18 GB patients. Immunohistochemical analysis of tumor samples revealed ERp57/PDIA3 expression in GB cells as well as in GAMs. The ERp57/PDIA3 levels were higher in GAMs than in the microglia present in the surrounding parenchyma. Therefore, we studied the role of PDIA3 modulation in microglia-glioma interaction, based on the ability of conditioned media collected from human GB cells to induce the activation of microglial cells. The results indicated that reduced PDIA3 expression/activity in GB cells significantly limited the microglia pro-tumor polarization towards the M2 phenotype and the production of pro-inflammatory factors. Our data support a role of PDIA3 expression in GB-mediated protumor activation of microglia.

MicroRNA-374b-5p Functions as a Tumor Suppressor in Non-Small Cell Lung Cancer by Targeting FOXP1 and Predicts Prognosis of Cancer Patients

Background

Lung cancer remains the most frequent malignancy worldwide with increasing morbidity and mortality. This study aimed to assess the expression of microRNA-374b-5p (miR-374b-5p) in tissues and cell lines of non-small cell lung cancer (NSCLC) and to evaluate the prognostic value of miR-374b-5p as well as its biological function in tumor progression.

Materials and Methods

Expression of miR-374b-5p in NSCLC patients and cells was estimated using quantitative real-time PCR. The prognostic value of miR-374b-5p was evaluated using Kaplan–Meier method and Cox regression analysis. Gain-of-function and loss-of-function cell experiments were performed to examine the effects of miR-374b-5p on NSCLC cell proliferation, migration and invasion. A luciferase activity assay was used to confirm the target gene of miR-374b-5p.

Results

miR-374b-5p expression levels were decreased in tumorous tissues and cell lines compared with the normal tissues or cells (P < 0.05). The expression of miR-374b-5p was associated with the patients’ tumor size, lymph node metastasis and TNM stage (all P < 0.05). Patients with low miR-374b-5p expression have a shorter survival time (log-rank P = 0.001), and the downregulated expression of miR-374b-5p was determined to be an independent prognostic indicator of NSCLC. In NSCLC cells, the overexpression of miR-374b-5p could inhibit NSCLC cell proliferation, migration and invasion and could directly target FOXP1.

Conclusion

This study found that the decreased miR-374b-5p predicts poor prognosis of NSCLC, and the upregulation of miR-374b-5p can inhibit NSCLC cell proliferation, migration and invasion. The data obtained from this study provide a novel candidate prognostic biomarker and a potential therapeutic target for NSCLC.

YY1-induced upregulation of FOXP4-AS1 and FOXP4 promote the proliferation of esophageal squamous cell carcinoma cells

Esophageal squamous cell carcinoma (ESCC) belongs to one of the most common malignant tumors worldwide and possesses high mortality. Long non-coding RNAs (lncRNAs) have been demonstrated to be essential biological participants in the progression of ESCC. On the basis of bio-informatics prediction, forkhead box P4 antisense RNA 1 (FOXP4-AS1) and forkhead box P4 (FOXP4) were upregulated in esophageal carcinoma samples and were positively correlated with each other. The present study aimed to explore the function of FOXP4-AS1 and FOXP4 in ESCC cells. Function assays disclosed that knockdown of FOXP4-AS1 or FOXP4 efficiently suppressed cell proliferation and induced cell apoptosis. Moreover, FOXP4-AS1 positively regulated FOXP4 by interacting with insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) to stabilize FOXP4 messenger RNA. In addition, FOXP4-AS1 could upregulate the expression of FOXP4 by sponging miR-3184-5p. Finally, we found that Yin Yang 1 (YY1) is a transcription factor that can transcriptionally activate both FOXP4-AS1 and FOXP4 in ESCC cells. In a word, YY1-induced upregulation of FOXP4-AS1 and FOXP4 promote the proliferation of ESCC cells.

IFITM3/STAT3 axis promotes glioma cells invasion and is modulated by TGF-β

Glioma is the most aggressive primary brain tumor. We have previously provided evidence that IFITM3 promoted glioma cells migration. However, the mechanism of how IFITM3 regulates glioma cells invasion and whether IFITM3 participates in TGF-β-mediated glioma invasion are still unknown. In this paper, we proved that IFITM3 was notably up-regulated in glioma tissues. Knockdown of IFITM3 suppressed STAT3 phosphorylation in vitro, and a specific STAT3 inhibitor AG490 reversed IFITM3-induced invasion of glioma cells. Furthermore, IFITM3 expression was induced by TGF-β in glioma and IFITM3 knockdown abolished TGF-β-mediated glioma cells invasion. Collectively, the results indicate that IFITM3/STAT3 axis may promote TGF-β-induced glioma cells invasion. This study provided some suggestions for the clinical treatment of the brain tumor.

USF2 enhances the osteogenic differentiation of PDLCs by promoting ATF4 transcriptional activities

OBJECTIVE

Our study aimed to elucidate the regulatory molecules related to the osteogenic differentiation of periodontal ligament cells (PDLCs).

BACKGROUND

Periodontal ligament cells are a favorable source for cell-based therapy in periodontal bone engineering and regeneration due to their potential multilineage differentiation ability. However, the molecular mechanism and signaling pathways related to the osteogenic differentiation of PDLCs are still unclear.

METHODS

Osteoblast-specific protein expression levels were examined by ELISA in osteogenic-induced PDLCs (induced-PDLC group). A microarray assay and a bioinformatics analysis were carried out to reveal significantly expressed genes and the related pathways in induced-PDLCs, and these findings were then confirmed by qRT-PCR and a luciferase reporter assay. Finally, overexpressing and silencing gene systems were established to identify the specific transcriptional relationship and function of the target genes on the osteogenic differentiation of PDLCs.

RESULTS

Osteogenically differentiated PDLCs with high levels of osteoblast-specific proteins were established. The upstream stimulatory factor 2 (USF2) and activating transcription factor 4 (ATF4) mRNA levels were upregulated the most through the MAPK signaling pathway in the induced-PDLC group. USF2 could bind to the transcriptional initiation region of ATF4 and regulate its transcriptional activities. Additionally, the overexpression of USF2 promoted osteoblast-specific gene expression and the Alizarin red staining of PDLCs, while simultaneously overexpressing USF2 and silencing ATF4 reversed the favorable osteogenic effect of the induced-PDLCs by reducing osteoblast-specific gene expression and the Alizarin red staining level.

CONCLUSION

Our study demonstrated that USF2 could enhance the osteogenic differentiation of PDLCs by regulating ATF4 transcriptional activities, which provides a new strategy to utilize USF2 and ATF4 as potential target molecules for periodontal bone regeneration.

Circular RNA circSCAF11 Accelerates the Glioma Tumorigenesis through the miR-421/SP1/VEGFA Axis

Circular RNAs (circRNAs) are a novel category of non-coding RNAs, and they have been identified to participate in glioma tumorigenesis. Here we investigated the functions of circRNA circSCAF11 in glioma genesis, and we unveiled its molecular mechanism in the pathophysiological process. Expression levels of circSCAF11, miR-421, and SP1 mRNA were measured using RT-PCR. Proteins were measured using western blotting. The tumor phenotypes of glioma cells were detected using flow cytometry and Cell Counting Kit-8 (CCK-8), transwell, and xenograft mouse assays. The combination within circSCAF11, miR-421, and SP1 was validated using luciferase reporter assay or RNA pull-down assay. The binding of transcription factor SP1 with vascular endothelial cell growth factor A (VEGFA) promoter was inspected using chromatin immunoprecipitation (ChIP). circSCAF11 expression was found to be significantly upregulated in the glioma tissue specimens and cell lines. The ectopic overexpression of circSCAF11 was closely correlated with the poor clinical outcome of glioma patients. Functionally, knockdown of circSCAF11 inhibited the proliferation, invasion, and tumor growth and induced the G0/G1 phase arrest. Mechanically, circSCAF11 positively regulated the SP1 expression through sponging miR-421. Moreover, transcription factor SP1 activated the transcription of VEGFA, constructing the circSCAF11/miR-421/SP1/VEGFA axis in the glioma genesis. The findings in this research illustrate that circSCAF11 accelerates glioma tumorigenesis through the miR-421/SP1/VEGFA axis, providing a potential target for circRNA and glioma treatment.

FOXP1-induced lncRNA CLRN1-AS1 acts as a tumor suppressor in pituitary prolactinoma by repressing the autophagy via inactivating Wnt/β-catenin signaling pathway

As the commonest type of functional pituitary tumor, prolactinoma takes up around 40-60% of functional pituitary tumors. Despite dedications attributed to the treatment of prolactinoma, complete cure remains difficult. Hence, it is of significance to bring to light the underlying mechanism of prolactinoma. Long noncoding RNAs (lncRNAs) are a group of transcripts which can regulate various biological processes. In the present study, we explored an lncRNA that was differentially downregulated in prolactinoma samples. LncRNA clarin 1 antisense RNA 1 (CLRN1-AS1) was downregulated in 42 patient samples and inactivated the Wnt/β-catenin signaling pathway. Functionally, CLRN1-AS1 suppressed cell proliferation, promoted apoptosis, and inhibited autophagy. Subcellular fractionation assay revealed that CLRN1-AS1 was located in the cytoplasm of prolactinoma cells. Based on bioinformatics analysis and mechanism experiments, we determined that CLRN1-AS1 acted as a competing endogenous RNA (ceRNA) by sponging miR-217 to upregulate the dickkopf WNT signaling pathway inhibitor 1 (DKK1). Furthermore, Forkhead box P1 (FOXP1) was verified to be a transcription suppressor of CLRN1-AS1. In summary, this study revealed that FOXP1-induced CLRN1-AS1 regulated cellular functions in pituitary prolactinoma by sponging miR-217 to release the DKK1/Wnt/β-catenin signaling pathway.

SP1 induced lncRNA CASC11 accelerates the glioma tumorigenesis through targeting FOXK1 via sponging miR-498

The biological functions of long noncoding RNAs (lncRNAs) in the glioma have gained much attention in recent researches. However, the deepgoing mechanism by which lncRNA regulates the gliomagenesis is still ambiguous. In this work, we found that lncRNA CASC11 was significantly up-regulated in the glioma specimens and cells, and the ectopic overexpression indicated the poor prognosis of glioma patients. CASC11 expression could be activated by the transcription factor SP1. In vivo and vitro, the knockdown of CASC11 impaired the proliferation, migration and tumor growth of glioma cells. In mechanical experiments, the miR-498 was found to target the 3'-UTR of lncRNA CASC11 and FOXK1 mRNA. Taken together, the data suggest the regulation of SP1/CASC11/miR-498/FOXK1 in the gliomagenesis, which might provide a potential therapeutic strategy for glioma.

STAT3 promotes tumour progression in glioma by inducing FOXP1 transcription

Objective

This paper investigated the effects of STAT3 through promoting FOXP1 transcription on proliferation, apoptosis and invasion in glioma cells.

Methods

Quantitative real‐time PCR (qRT‐PCR) and Western blot assay were administered to assess the mRNA and protein expression levels of STAT3 and FOXP1 in glioma tissues and cells, respectively. Luciferase reporter and Chromatin Immunoprecipitation (ChIP) assays were implemented to determine the correlation between STAT3 and FOXP1. MTT and colony formation assays were conducted to identify cell growth. Flow cytometry was run to detect the cell apoptosis rate of glioma cells. Transwell assays were conducted to reveal cell invasion ability.

Results

The mRNA and protein expression levels of STAT3 were highly expressed in glioma tissues and cells. After cells transfected with siRNA of STAT3, both STAT3 and FOXP1 were simultaneously downregulated. STAT3 directly regulated FOXP1 transcription. STAT3 promoted cell proliferation, inhibited cell apoptosis and enhanced cell invasion through promoting FOXP1 transcription in glioma cells.

Conclusion

In summary, STAT3 gene was a transcriptional regulator of FOXP1. Depleted STAT3 restrained cell proliferation and invasion, promoted cell apoptosis in glioma cells. This molecular mechanism between STAT3 and FOXP1 can serve as a therapeutic target for glioma treatment.