SGEF Is Regulated via TWEAK/Fn14/NF-κB Signaling and Promotes Survival by Modulation of the DNA Repair Response to Temozolomide

Intercellular adhesion molecule-1 suppresses TMZ chemosensitivity in acquired TMZ-resistant gliomas by increasing assembly of ABCB1 on the membrane

AIMS

Despite aggressive treatment, the recurrence of glioma is an inevitable occurrence, leading to unsatisfactory clinical outcomes. A plausible explanation for this phenomenon is the phenotypic alterations that glioma cells undergo aggressive therapies, such as TMZ-therapy. However, the underlying mechanisms behind these changes are not well understood.

METHODS

The TMZ chemotherapy resistance model was employed to assess the expression of intercellular adhesion molecule-1 (ICAM1) in both in vitro and in vivo settings. The potential role of ICAM1 in regulating TMZ chemotherapy resistance was investigated through knockout and overexpression techniques. Furthermore, the mechanism underlying ICAM1-mediated TMZ chemotherapy resistance was examined using diverse molecular biological methods, and the lipid raft protein was subsequently isolated to investigate the cellular subcomponents where ICAM1 operates.

RESULTS

Acquired TMZ resistant (TMZ-R) glioma models heightened production of intercellular adhesion molecule-1 (ICAM1) in TMZ-R glioma cells. Additionally, we observed a significant suppression of TMZ-R glioma proliferation upon inhibition of ICAM1, which was attributed to the enhanced intracellular accumulation of TMZ. Our findings provide evidence supporting the role of ICAM1, a proinflammatory marker, in promoting the expression of ABCB1 on the cell membrane of TMZ-resistant cells. We have elucidated the mechanistic pathway by which ICAM1 modulates phosphorylated moesin, leading to an increase in ABCB1 expression on the membrane. Furthermore, our research has revealed that the regulation of moesin by ICAM1 was instrumental in facilitating the assembly of ABCB1 exclusively on the lipid raft of the membrane.

CONCLUSIONS

Our findings suggest that ICAM1 is an important mediator in TMZ-resistant gliomas and targeting ICAM1 may provide a new strategy for enhancing the efficacy of TMZ therapy against glioma.

Relating enhancer genetic variation across mammals to complex phenotypes using machine learning

Protein-coding differences between species often fail to explain phenotypic diversity, suggesting the involvement of genomic elements that regulate gene expression such as enhancers. Identifying associations between enhancers and phenotypes is challenging because enhancer activity can be tissue-dependent and functionally conserved despite low sequence conservation. We developed the Tissue-Aware Conservation Inference Toolkit (TACIT) to associate candidate enhancers with species' phenotypes using predictions from machine learning models trained on specific tissues. Applying TACIT to associate motor cortex and parvalbumin-positive interneuron enhancers with neurological phenotypes revealed dozens of enhancer-phenotype associations, including brain size-associated enhancers that interact with genes implicated in microcephaly or macrocephaly. TACIT provides a foundation for identifying enhancers associated with the evolution of any convergently evolved phenotype in any large group of species with aligned genomes.

Targeting fibroblast growth factor (FGF)-inducible 14 (Fn14) for tumor therapy

Fibroblast growth factor-inducible 14 (Fn14) is a member of the tumor necrosis factor (TNF) receptor superfamily (TNFRSF) and is activated by its ligand TNF-like weak inducer of apoptosis (TWEAK). The latter occurs as a homotrimeric molecule in a soluble and a membrane-bound form. Soluble TWEAK (sTWEAK) activates the weakly inflammatory alternative NF-κB pathway and sensitizes for TNF-induced cell death while membrane TWEAK (memTWEAK) triggers additionally robust activation of the classical NF-κB pathway and various MAP kinase cascades. Fn14 expression is limited in adult organisms but becomes strongly induced in non-hematopoietic cells by a variety of growth factors, cytokines and physical stressors (e.g., hypoxia, irradiation). Since all these Fn14-inducing factors are frequently also present in the tumor microenvironment, Fn14 is regularly found to be expressed by non-hematopoietic cells of the tumor microenvironment and most solid tumor cells. In general, there are three possibilities how the tumor-Fn14 linkage could be taken into consideration for tumor therapy. First, by exploitation of the cancer associated expression of Fn14 to direct cytotoxic activities (antibody-dependent cell-mediated cytotoxicity (ADCC), cytotoxic payloads, CAR T-cells) to the tumor, second by blockade of potential protumoral activities of the TWEAK/Fn14 system, and third, by stimulation of Fn14 which not only triggers proinflammtory activities but also sensitizes cells for apoptotic and necroptotic cell death. Based on a brief description of the biology of the TWEAK/Fn14 system and Fn14 signaling, we discuss the features of the most relevant Fn14-targeting biologicals and review the preclinical data obtained with these reagents. In particular, we address problems and limitations which became evident in the preclinical studies with Fn14-targeting biologicals and debate possibilities how they could be overcome.

Arginine Methyltransferase PRMT7 Deregulates Expression of RUNX1 Target Genes in T-Cell Acute Lymphoblastic Leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy with no well-established prognostic biomarkers. We examined the expression of protein arginine methyltransferases across hematological malignancies and discovered high levels of PRMT7 mRNA in T-ALL, particularly in the mature subtypes of T-ALL. The genetic deletion of PRMT7 by CRISPR-Cas9 reduced the colony formation of T-ALL cells and changed arginine monomethylation patterns in protein complexes associated with the RNA and DNA processing and the T-ALL pathogenesis. Among them was RUNX1, whose target gene expression was consequently deregulated. These results suggest that PRMT7 plays an active role in the pathogenesis of T-ALL.

Seven key hub genes identified by gene co-expression network in cutaneous squamous cell carcinoma

Background

Cutaneous squamous cell carcinoma (cSCC) often follows actinic keratosis (AK) and is the second most common skin cancer worldwide. To reduce metastasis risk, it is important to diagnose and treat cSCC early. This study aimed to identify hub genes associated with cSCC and AK.

Methods

This study used three datasets GSE45216, GSE98774, and GSE108008. We combined samples from the GSE45216 and GSE98774 datasets into the new dataset GSE45216–98774. We applied a weighted gene co-expression network analysis (WGCNA) to investigate key modules and hub genes associated with cSCC and AK. We considered the hub genes found in both the GSE45216–98774 and GSE108008 datasets as validated hub genes. We tested whether the expression of hub genes could predict patient survival outcomes in other cancers using TCGA pan-cancer data.

Results

We identified modules most relevant to cSCC and AK. Additionally, we identified and validated seven hub genes of cSCC: GATM, ARHGEF26, PTHLH, MMP1, POU2F3, MMP10 and GATA3. We did not find validated hub genes for AK. Each hub gene was significantly associated with the survival of various cancer types. Only GATA3 was significantly associated with melanoma survival.

Conclusions

We applied WGCNA to find seven hub genes that play important roles in cSCC tumorigenesis. These results provide new insights that help explain the pathogenesis of cSCC. These hub genes may become biomarkers or therapeutic targets for accurate diagnosis and treatment of cSCC in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08604-y.

Genes and pathways monotonically dysregulated during progression from normal through leukoplakia to gingivo-buccal oral cancer

Oral squamous cell carcinoma of the gingivo-buccal region (OSCC-GB) accounts for the highest cancer morbidity and mortality among men in India. It has been observed that about one-third of individuals with oral leukoplakia, a dysplastic precancerous lesion in the oral cavity, progress to oral cancer. We aimed to identify systematic transcriptomic changes as a normal tissue in the oral cavity progresses to frank OSCC-GB. Seventy-two OSCC-GB patients, from multiple hospitals, were recruited, and transcriptome analysis of tumor and adjacent normal tissue (of all patients) and adjacent leukoplakia tissue (of a subset of 25 unselected patients with concomitant leukoplakia) was performed. We have identified many differences in the transcriptomic profiles between OSCC-GB and squamous cell carcinoma of the head and neck regions. Compared to the normal/precancerous tissue, significant enrichment of ECM−receptor interaction, PI3K-Akt signaling, cytokine−cytokine receptor interaction, focal adhesion, and cell cycle pathways were observed in OSCC-GB. Using gene set enrichment analysis, we identified a profound role of interferon receptor signaling in tumor growth by activating immune evasion mechanisms. The role of tumor-infiltrating immune cells further supported the growth and immunosuppressive mechanism of tumor tissues. Some immune evasion genes—CD274, CD80, and IDO1—were found to be activated even in the precancerous tissue. Taken together, our findings provide a clear insight into the sequential genetic dysregulation associated with progression to oral cancer. This insight provides a window to the development of predictive biomarkers and therapeutic targets for gingivo-buccal oral cancer.

A Novel Immune-Related Prognostic Biomarker and Target Associated With Malignant Progression of Glioma

Background

Glioma is one of the most common malignancies in the central nervous system and has limited effective therapeutic options. Therefore, we sought to identify a suitable target for immunotherapy.

Materials and Methods

We screened prognostic genes for glioma in the CGGA database and GSE43378 dataset using survival analysis, receiver operating characteristic (ROC) curves, independent prognostic analysis, and clinical correlation analysis. The results were intersected with immune genes from the ImmPort database through Venn diagrams to obtain likely target genes. The target genes were validated as prognostically relevant immune genes for glioma using survival, ROC curve, independent prognostic, and clinical correlation analyses in samples from the CGGA database and GSE43378 dataset, respectively. We also constructed a nomogram using statistically significant glioma prognostic factors in the CGGA samples and verified their sensitivity and specificity with ROC curves. The functions, pathways, and co-expression-related genes for the glioma target genes were assessed using PPI networks, enrichment analysis, and correlation analysis. The correlation between target gene expression and immune cell infiltration in glioma and the relationship with the survival of glioma patients were investigated using the TIMER database. Finally, target gene expression in normal brain, low-grade glioma, and high-grade glioma tissues was detected using immunohistochemical staining.

Results

We identified TNFRSF12A as the target gene. Satisfactory results from survival, ROC curve, independent prognosis, and clinical correlation analyses in the CGGA and GSE43378 samples verified that TNFRSF12A was significantly associated with the prognosis of glioma patients. A nomogram was constructed using glioma prognostic correlates, including TNFRSF12A expression, primary-recurrent-secondary (PRS) type, grade, age, chemotherapy, IDH mutation, and 1p19q co-deletion in CGGA samples with an AUC value of 0.860, which illustrated the accuracy of the prognosis prediction. The results of the TIMER analysis validated the significant correlation of TNFRSF12A with immune cell infiltration and glioma survival. The immunohistochemical staining results verified the progressive up-regulation of TNFRSF12A expression in normal brain, low-grade glioma, and high-grade glioma tissues.

Conclusion

We concluded that TNFRSF12A was a viable prognostic biomarker and a potential immunotherapeutic target for glioma.

The TNF receptor family member Fn14 is highly expressed in recurrent glioblastoma and in GBM patient-derived xenografts with acquired temozolomide resistance

Background

Glioblastoma (GBM) is a difficult to treat brain cancer that nearly uniformly recurs, and recurrent tumors are largely therapy resistant. Our prior work has demonstrated an important role for the tumor necrosis factor-like weak inducer of apoptosis (TWEAK) receptor fibroblast growth factor-inducible 14 (Fn14) in GBM pathobiology. In this study, we investigated Fn14 expression in recurrent GBM and in the setting of temozolomide (TMZ) resistance.

Methods

Fn14 mRNA expression levels in nonneoplastic brain, primary (newly diagnosed) GBM, and recurrent GBM (post-chemotherapy and radiation) specimens were obtained from The Cancer Genome Atlas data portal. Immunohistochemistry was performed using nonneoplastic brain, patient-matched primary and recurrent GBM, and gliosarcoma (GSM) specimens to examine Fn14 protein levels. Western blot analysis was used to compare Fn14 expression in parental TMZ-sensitive or matched TMZ-resistant patient-derived xenografts (PDXs) established from primary or recurrent tumor samples. The migratory capacity of control and Fn14-depleted TMZ-resistant GBM cells was assessed using the transwell migration assay.

Results

We found that Fn14 is more highly expressed in recurrent GBM tumors than their matched primary GBM counterparts. Fn14 expression is also significantly elevated in GSM tumors. GBM PDX cells with acquired TMZ resistance have higher Fn14 levels and greater migratory capacity than their corresponding parental TMZ-sensitive cells, and the migratory difference is due, at least in part, to Fn14 expression in the TMZ-resistant cells.

Conclusions

This study demonstrates that the Fn14 gene is highly expressed in recurrent GBM, GSM, and TMZ-resistant GBM PDX tumors. These findings suggest that Fn14 may be a valuable therapeutic target or drug delivery portal for treatment of recurrent GBM and GSM patients.

Autophagy modulates temozolomide-induced cell death in alveolar Rhabdomyosarcoma cells

Rhabdomyosarcoma (RMS) is a muscle-derived tumor. In both pre-clinical and clinical studies Temozolomide (TMZ) has been recently tested against RMS; however, the precise mechanism of action of TMZ in RMS remains unclear. Here we demonstrate that TMZ decreases the cell viability of the RH30 RMS and C2C12 cell line, where cells display evidence of mitochondrial outer membrane permeability. Interestingly, the C2C12 mouse myoblast line was relatively more resistant to TMZ-induced apoptosis. Moreover, we observed that TMZ activated biochemical and morphological markers of autophagy in both cell lines. Autophagy inhibition in both RH30 and C2C12 cells significantly increased TMZ-induced cell death. In RH30 cells, TMZ increased Mcl-1 and Bax protein expression compared to corresponding time match controls while in C2C12 Mcl-1, Bcl-2, Bcl-XL, and Bax protein expression were not changed. Baf-A1 co-treatment with TMZ significantly decrease Mcl-1 expression compared to TMZ while increase Bax expression in C2C12 cells (Bcl2 and Bcl-XL do not significantly change in Baf-A1/TMZ co-treatment). Using a three-dimensional (3D) C2C12 and RH30 culture model we demonstrated that TMZ is significantly more toxic in RH30 cells (live/dead assay). Additionally, we have observed in our 3D culture model that TMZ induced both apoptosis (cleavage of PARP) and autophagy (LC3-puncta and localization of LC3/p62). Therefore, our data demonstrate that TMZ induces simultaneous autophagy and apoptosis in both RH30 and C2C12 cells in 2D and 3D culture model, where RH30 cells are more sensitive to TMZ-induced death. Furthermore, autophagy serves to protect RH30 cells from TMZ-induced death.

Overexpression of Fn14 in gliomas: tumor progression and poor prognosis

AIM

To confirm whether the expression level of Fn14 could affect progression or prognosis of glioma patients.

METHODS

Glioma cohorts in The Cancer Genome Atlas, Gene Expression Omnibus and Chinese Glioma Genome Atlas databases were comprehensively analyzed.

RESULTS

Low-grade patients had lower expression level of Fn14, while patients with higher expression of Fn14 tended to harbor shorter overall survival and disease-free survival. The expression level of Fn14 was downregulated by IDH1/IDH2 mutations while its gene body methylation was upregulated. After adjusting age, the expression level of Fn14 was still significantly associated with overall survival and disease-free survival in low-grade gliomas. In a cell line data analysis, Fn14 expression was positively correlated with temozolomide dosage.

CONCLUSION

Fn14 was an independent predictive biomarker for the progression and prognosis in low-grade gliomas.

EGFRvIII-Stat5 Signaling Enhances Glioblastoma Cell Migration and Survival

Glioblastoma multiforme (GBM) is the most common brain malignancies in adults. Most GBM patients succumb to the disease less than 1 year after diagnosis due to the highly invasive nature of the tumor, which prevents complete surgical resection and gives rise to tumor recurrence. The invasive phenotype also confers radioresistant and chemoresistant properties to the tumor cells; therefore, there is a critical need to develop new therapeutics that target drivers of GBM invasion. Amplification of EGFR is observed in over 50% of GBM tumors, of which half concurrently overexpress the variant EGFRvIII, and expression of both receptors confers a worse prognosis. EGFR and EGFRvIII cooperate to promote tumor progression and invasion, in part, through activation of the Stat signaling pathway. Here, it is reported that EGFRvIII activates Stat5 and GBM invasion by inducing the expression of a previously established mediator of glioma cell invasion and survival: fibroblast growth factor-inducible 14 (Fn14). EGFRvIII-mediated induction of Fn14 expression is Stat5 dependent and requires activation of Src, whereas EGFR regulation of Fn14 is dependent upon Src-MEK/ERK-Stat3 activation. Notably, treatment of EGFRvIII-expressing GBM cells with the FDA-approved Stat5 inhibitor pimozide blocked Stat5 phosphorylation, Fn14 expression, and cell migration and survival. Because EGFR inhibitors display limited therapeutic efficacy in GBM patients, the EGFRvIII-Stat5-Fn14 signaling pathway represents a node of vulnerability in the invasive GBM cell populations.Implications: Targeting critical effectors in the EGFRvIII-Stat5-Fn14 pathway may limit GBM tumor dispersion, mitigate therapeutic resistance, and increase survival. Mol Cancer Res; 16(7); 1185-95. ©2018 AACR.

Differential expression of the TWEAK receptor Fn14 in IDH1 wild-type and mutant gliomas

The TNF receptor superfamily member Fn14 is overexpressed by many solid tumor types, including glioblastoma (GBM), the most common and lethal form of adult brain cancer. GBM is notable for a highly infiltrative growth pattern and several groups have reported that high Fn14 expression levels can increase tumor cell invasiveness. We reported previously that the mesenchymal and proneural GBM transcriptomic subtypes expressed the highest and lowest levels of Fn14 mRNA, respectively. Given the recent histopathological re-classification of human gliomas by the World Health Organization based on isocitrate dehydrogenase 1 (IDH1) gene mutation status, we extended this work by comparing Fn14 gene expression in IDH1 wild-type (WT) and mutant (R132H) gliomas and in cell lines engineered to overexpress the IDH1 R132H enzyme. We found that both low-grade and high-grade (i.e., GBM) IDH1 R132H gliomas exhibit low Fn14 mRNA and protein levels compared to IDH1 WT gliomas. Forced overexpression of the IDH1 R132H protein in glioma cells reduced Fn14 expression, while treatment of IDH1 R132H-overexpressing cells with the IDH1 R132H inhibitor AGI-5198 or the DNA demethylating agent 5-aza-2'-deoxycytidine increased Fn14 expression. These results support a role for Fn14 in the more aggressive and invasive phenotype associated with IDH1 WT tumors and indicate that the low levels of Fn14 gene expression noted in IDH1 R132H mutant gliomas may be due to epigenetic regulation via changes in DNA methylation.

Periarteriolar Glioblastoma Stem Cell Niches Express Bone Marrow Hematopoietic Stem Cell Niche Proteins

In glioblastoma, a fraction of malignant cells consists of therapy-resistant glioblastoma stem cells (GSCs) residing in protective niches that recapitulate hematopoietic stem cell (HSC) niches in bone marrow. We have previously shown that HSC niche proteins stromal cell-derived factor-1α (SDF-1α), C-X-C chemokine receptor type 4 (CXCR4), osteopontin (OPN), and cathepsin K (CatK) are expressed in hypoxic GSC niches around arterioles in five human glioblastoma samples. In HSC niches, HSCs are retained by binding of SDF-1α and OPN to their receptors CXCR4 and CD44, respectively. Protease CatK cleaves SDF-1α to release HSCs out of niches. The aim of the present study was to reproduce the immunohistochemical localization of these GSC markers in 16 human glioblastoma samples with the addition of three novel markers. Furthermore, we assessed the type of blood vessels associated with GSC niches. In total, we found seven GSC niches containing CD133-positive and nestin-positive GSCs as a single-cell layer exclusively around the tunica adventitia of 2% of the CD31-positive and SMA-positive arterioles and not around capillaries and venules. Niches expressed SDF-1α, CXCR4, CatK, OPN, CD44, hypoxia-inducible factor-1α, and vascular endothelial growth factor. In conclusion, we show that GSC niches are present around arterioles and express bone marrow HSC niche proteins.

Identification of aurintricarboxylic acid as a selective inhibitor of the TWEAK-Fn14 signaling pathway in glioblastoma cells

The survival of patients diagnosed with glioblastoma (GBM), the most deadly form of brain cancer, is compromised by the proclivity for local invasion into the surrounding normal brain, which prevents complete surgical resection and contributes to therapeutic resistance. Tumor necrosis factor-like weak inducer of apoptosis (TWEAK), a member of the tumor necrosis factor (TNF) superfamily, can stimulate glioma cell invasion and survival via binding to fibroblast growth factor-inducible 14 (Fn14) and subsequent activation of the transcription factor NF-κB. To discover small molecule inhibitors that disrupt the TWEAK-Fn14 signaling axis, we utilized a cell-based drug-screening assay using HEK293 cells engineered to express both Fn14 and a NF-κB-driven firefly luciferase reporter protein. Focusing on the LOPAC1280 library of 1280 pharmacologically active compounds, we identified aurintricarboxylic acid (ATA) as an agent that suppressed TWEAK-Fn14-NF-κB dependent signaling, but not TNFα-TNFR-NF-κB driven signaling. We demonstrated that ATA repressed TWEAK-induced glioma cell chemotactic migration and invasion via inhibition of Rac1 activation but had no effect on cell viability or Fn14 expression. In addition, ATA treatment enhanced glioma cell sensitivity to both the chemotherapeutic agent temozolomide (TMZ) and radiation-induced cell death. In summary, this work reports a repurposed use of a small molecule inhibitor that targets the TWEAK-Fn14 signaling axis, which could potentially be developed as a new therapeutic agent for treatment of GBM patients.

TWEAK-Fn14 Influences Neurogenesis Status via Modulating NF-κB in Mice with Spinal Cord Injury

The aim of our research is to investigate the regulatory role of TNF-like weak inducer of apoptosis- fibroblast growth factor-inducible 14 (TWEAK-Fn14) pathway in nuclear factor-kappa B (NF-κB) expression and neurogenesis status after spinal cord injury (SCI). We constructed a mice model of spinal cord injury and injected different lentiviral vectors which were transfected with TWEAK, TWEAK small interfering RNA (siRNA) and Fn14 siRNA into different groups of mice. Locomotor functional recovery status of the hind limb in mice was assessed using the Basso, Beattie and Bresnahan (BBB) test. Apoptosis status in the injured area was examined via TDT-mediated dUTP-biotin nick end-labeling (TUNEL) staining, the expression of GAP-43 in injured spinal cord was quantified by immunohistochemistry and expressions of TWEAK, Fn14, NF-κB, TNF-α, and IL-1β were evaluated by either western blot or ELISA. The expressions of TWEAK, Fn14, and NF-κB in the model group were significantly higher compared with those in the control group. Furthermore, the TWEAK group in which TWEAK was overexpressed exhibited significantly higher expressions of TWEAK, Fn14, and NF-κB, TNF-α and IL-1β in relation to those in the model group (P < 0.05 for all). Moreover, the transfection of Fn14 siRNA antagonized the above effect of TWEAK transfection on injured mice. On the other hand, the TWEAK siRNA group in which the expression of TWEAK was inhibited exhibited significantly lower expressions of TWEAK, Fn14, NF-κB, TNF-α, and IL-1β (P < 0.05 for all). Moreover, the transfection of TWEAK siRNA enhanced the locomotor functional recovery status in injured mice and suppressed the apoptosis of injured areas (P < 0.05 for all). In conclusion, stimulating the TWEAK-Fn14 pathway may elevate the expression of NF-κB, thereby slow the function recovery of SCI mice whereas inhibiting the TWEAK-Fn14 pathway may improve the neurogenesis status in mice with spinal cord injuries.