Activation of STAT1 by the FRK tyrosine kinase is associated with human glioma growth

Multilevel chitosan-gelatin particles loaded with P4HA1 siRNA suppress glioma development

It has been reported that prolyl 4-hydroxylase subunit alpha 1 (P4HA1) promoted tumor growth and metastasis of glioma; thus, targeting P4HA1 may be a promising therapeutic strategy against glioma. In consideration of the instability of siRNA in vivo, the chitosan-gelatin microspheres loaded with P4HA1 siRNA (P4HA1 siRNA@CGM) were employed. Firstly, the gel electrophoresis and hemolytic test were performed to assess the stability and blood compatibility of P4HA1 siRNA@CGM. Then, methyl thiazolyl tetrazolium (MTT), cell colony formation, Transwell assay, wound healing assay, gliosphere formation, tube formation, and Western blot were performed to assess the effects of P4HA1 siRNA@CGM on the biological functions of glioma. Finally, 125I-labeled P4HA1 siRNA@CGM was injected into the xenograft mice, radionuclide imaging was recorded, Ki67 and terminal deoxynucleoitidyl transferase-mediated nick end labeling (TUNEL) staining was performed to assess the effects of P4HA1 siRNA@CGM on tumor growth and apoptosis of glioma in vivo. The results showed that P4HA1 siRNA and P4HA1 siRNA@CGM not only markedly inhibited the proliferation, metastasis, gliosphere formation, and the protein levels of interstitial markers (N-cadherin and vimentin) and the transcription factors of epithelial-mesenchymal transition (EMT) (Snail, Slug, and Twist1) in glioma cells, but also inhibited the tube formation in human brain microvascular endothelial cells (HBMECs), and P4HA1 siRNA@CGM exhibited the better inhibitory effects than P4HA1 siRNA. Above results suggested the feasibility of P4HA1 siRNA@CGM in the clinical treatment of glioma.

FRK inhibits glioblastoma progression via phosphorylating YAP and inducing its ubiquitylation and degradation by Siah1

BACKGROUND

We previously report that yes-associated protein (YAP), the core downstream effector of Hippo pathway, promotes the malignant progression of glioblastoma (GBM). However, although classical regulatory mechanisms of YAP are well explored, how YAP is modulated by the Hippo-independent manner remains poorly understood. Meanwhile, the nonreceptor tyrosine kinase Fyn-related kinase (FRK), which exhibits low expression and possesses tumor suppressor effects in GBM, is reported to be involved in regulation of protein phosphorylation. Here, we examined whether FRK could impede tumor progression by modulating YAP activities.

METHODS

Human GBM cells and intracranial GBM model were used to assess the effects of FRK and YAP on the malignant biological behaviors of GBM. Immunoblotting and immunohistochemistry were used to detect the expression of core proteins in GBM tissues. Co-immunoprecipitation, proximity ligation assay, luciferase assay and ubiquitination assay were utilized to determine the protein-protein interactions and related molecular mechanisms.

RESULTS

The expression levels of FRK and YAP were inversely correlated with each other in glioma tissues. In addition, FRK promoted the ubiquitination and degradation of YAP, leading to tumor suppression in vitro and in vivo. Mechanistically, FRK interacted with and phosphorylated YAP on Tyr391/407/444, which recruited the classical E3 ubiquitin ligase Siah1 to catalyze ubiquitination and eventually degradation of YAP. Siah1 is required for YAP destabilization initiated by FRK.

CONCLUSIONS

We identify a novel mechanism by which FRK orchestrates tumor-suppression effect through phosphorylating YAP and inducing its ubiquitination by Siah1. FRK-Siah1-YAP signaling axis may serve as a potential therapeutic target for GBM treatment.

Plasma-Derived Extracellular Vesicles Reveal Galectin-3 Binding Protein as Potential Biomarker for Early Detection of Glioma

Gliomas are the most common type of the malignant brain tumor, which arise from glial cells. They make up about 40% of all primary brain tumors and around 70% of all primary malignant brain tumors. They can occur anywhere in the central nervous system (CNS) and have a poor prognosis. The average survival of glioma patients is approximately 6-15 months with poor aspects of life. In this edge, identification of proteins secreted by cancer cells is of special interest because it may provide a better understanding of tumor progression and provide early diagnosis of the diseases. Extracellular vesicles (EVs) were isolated from pooled plasma of healthy controls (n=03) and patients with different grades of glioma (Grade I or II or III, n=03 each). Nanoparticle tracking analysis, western blot, and flow cytometry were performed to determine the size, morphology, the concentration of glioma-derived vesicles and EV marker, CD63. Further, iTRAQ-based LC-MS/MS analysis of EV protein was performed to determine the differential protein abundance in extracellular vesicles across different glioma grades. We further verified galectin-3 binding protein (LGALS3BP) by ELISA in individual blood plasma and plasma-derived vesicles from control and glioma patients (n=40 each). Analysis by Max Quant identified 123 proteins from the pooled patient exosomes, out of which 34, 21, and 14 proteins were found to be differentially abundant by more than 1.3-fold in the different grades of glioma grade I, pilocytic astrocytoma; grade II, diffuse astrocytoma; grade III, anaplastic astrocytoma, respectively, in comparison with the control samples. A total of seven proteins-namely, CRP, SAA2, SERPINA3, SAA1, C4A, LV211, and KV112-showed differential abundance in all the three grades. LGALS3BP was seen to be upregulated across the different grades, and ELISA analysis from individual blood plasma and plasma-derived extracellular vesicles confirmed the increased expression of LGALS3BP in glioma patients (p<0.001). The present study provides LGALS3BP as a potential biomarker for early detection of glioma and improve survival outcome of the patient. The present study further provides the information of progression and monitoring the tumor grades (grade 1, grade II, grade III).

CPVL promotes glioma progression via STAT1 pathway inhibition through interactions with the BTK/p300 axis

CPVL (carboxypeptidase, vitellogenic-like) is a serine carboxypeptidase that was first characterized in human macrophages. However, the function of CPVL remains unclear in a variety of tumors. The quantitative PCR (qPCR), Western blotting, and IHC assays were utilized to measure the CPVL expression. CPVL was significantly upregulated in glioma cells and tissues compared with normal cells and tissues, respectively. Moreover, high CPVL expression was correlated with advanced clinical grade and poor prognosis. Silencing of CPVL promoted glioma cell apoptosis, and it inhibited cell proliferation and tumorigenicity in vitro and in vivo. Ingenuity Pathway Analysis (IPA) demonstrated that CPVL silencing activated the IFN-γ/STAT1 signaling pathway, thereby inducing glioma cell apoptosis. Mechanistically, immunopurification, mass spectrometry, IP, and glutathione S-transferase (GST) pull-down experiments elucidated that CPVL physically interacts with Bruton’s tyrosine kinase (BTK) and downregulates the STAT1 phosphorylation through promoting p300-mediated STAT1 acetylation. Our findings reveal the crucial role of CPVL in promoting the progression of glioma through suppressing STAT1 phosphorylation. CPVL might serve as a potential prognostic biomarker and therapeutic target for the treatment of glioma.

An insertion variant of MGMT disrupts a STAT1 binding site and confers susceptibility to glioma

Background

O⁶-methylguanine-DNA methyltransferase (MGMT) is a pivotal enzyme for repairing DNA alkylation damage. Epigenetic modification of MGMT has been well known as a promising prognostic biomarker for glioma. However, the significance of genetic variations of MGMT in glioma carcinogenesis has not been fully elucidated.

Methods

The associations between expression quantitative trait loci (eQTLs) of MGMT and glioma susceptibility were evaluated in a case–control study of 1056 individuals. The function of susceptibility locus for glioma was explored with a set of biochemical assays, including luciferase reporter gene, EMSA and supershift EMSA, ChIP, and siRNA knockdown.

Results

We found that rs11016798 TT genotype was associated with a significantly decreased risk of glioma (OR = 0.57, 95% CI 0.39–0.85; P = 0.006). Stratification analyses indicated that the association between rs11016798 and glioma was more pronounced in males (OR = 0.62, 95% CI 0.40–0.97; P = 0.035), older subjects (OR = 0.46, 95% CI 0.27–0.80; P = 0.006), WHO grade IV glioma (OR = 0.58, 95% CI 0.35–0.96; P = 0.033), and IDH wildtype glioma (OR = 0.43, 95% CI 0.21–0.88; P = 0.022). We characterized an insertion variant rs10659396 in the upstream of MGMT as a causative variant. The risk allele rs10659396 ins allele was demonstrated to downregulate MGMT expression by disrupting a STAT1 binding site. Knockdown of STAT1 remarkably attenuated MGMT expression. Moreover, the rs10659396 allele-specific positive correlation was observed between the expression of STAT1 and MGMT in population.

Conclusions

The study demonstrates that an insertion variant of MGMT rs10659396 confers susceptibility to glioma by downregulating MGMT expression through disrupting a STAT1 binding site.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02211-4.

SH2B3, Transcribed by STAT1, Promotes Glioblastoma Progression Through Transducing IL-6/gp130 Signaling to Activate STAT3 Signaling

Glioblastoma (GBM) is the most common and aggressive brain tumor in adults. The aberrant activation of STAT3 commonly occurs in GBM and is a key player in GBM tumorigenesis. Yet, the aberrant activation of STAT3 signaling is not fully understood. Here, we report that SH2B adaptor protein 3 (SH2B3) is highly expressed in GBM and preferentially expressed in GBM stem cells (GSCs). Moreover, SH2B3 high expression predicts worse survival of GBM patients. Targeting SH2B3 considerably impairs GBM cell proliferation, migration, and GSCs' self-renewal in vitro as well as xenograft tumors growth in vivo. Additionally, we provide evidence suggesting that STAT1 directly binds to the promoter of SH2B3 and activates SH2B3 expression in the transcriptional level. Functionally, SH2B3 facilitates GBM progression via physically interacting with gp130 and acting as an adaptor protein to transduce IL-6/gp130/STAT3 signaling. Together, our work firstly uncovers that the STAT1/SH2B3/gp130/STAT3 signaling axis plays critical roles in promoting GBM progression and provides insight into new prognosis marker and therapeutic target in GBM.

LncRNA HOTTIP leads to osteoarthritis progression via regulating miR-663a/ Fyn-related kinase axis

BACKGROUND

Long non-coding RNA (lncRNA) has been implicated in the progression of osteoarthritis (OA). This study was aimed to explore the role and molecular mechanism of lncRNA HOXA terminal transcriptional RNA (HOTTIP) in the development of OA.

METHODS

The expression of HOTTIP, miR-663a and Fyn-related kinase (FRK) in the OA articular cartilage and OA chondrocyte model induced by IL-1β was determined by qRT-PCR. CCK-8, colony formation and flow cytometry were used to determine the cell proliferation and apoptosis of OA chondrocytes. The specific molecular mechanism of HOTTIP in OA chondrocytes was determined by dual luciferase reporter assay, qRT-PCR, western blotting and RNA pull-down.

RESULTS

The expression of HOTTIP and FRK were up-regulated, while miR-663a was down-regulated in OA cartilage tissues. Knockdown of HOTTIP decreased the proliferation and induced the apoptosis of OA cartilage model cells, while overexpression of HOTTIP increased the proliferation and reduced the apoptosis of OA cartilage model cells. Moreover, HOTTIP could bind to miR-663a as competitive endogenous RNA. Inhibition of miR-663a expression could alleviate the effect of HOTTIP knockdown on the proliferation and apoptosis of OA cartilage model cells. Furthermore, FRK was found to be a direct target of miR-663a, which could markedly down-regulate the expression of FRK in OA chondrocytes, while HOTTIP could remarkably up-regulate the expression of FRK. In addition, miR-663a inhibition increased the proliferation and reduced the apoptosis of OA cells, while FRK knockdown reversed the effect of miR-663a inhibition on the proliferation and apoptosis of OA cells. Meanwhile, overexpression of miR-663a decreased the proliferation and induced the apoptosis of OA cells, while overexpression of FRK reversed the effect of miR-663a overexpression on the proliferation and apoptosis of OA cells.

CONCLUSION

HOTTIP was involved in the proliferation and apoptosis of OA chondrocytes via miR-663a/ FRK axis, and HOTTIP/miR-663a/FRK might be a potential target for the treatment of OA.