Splicing machinery dysregulation drives glioblastoma development/aggressiveness: oncogenic role of SRSF3

Abstract Glioblastomas remain the deadliest brain tumour, with a dismal ∼12–16-month survival from diagnosis. Therefore, identification of new diagnostic, prognostic and therapeutic tools to tackle glioblastomas is urgently needed. Emerging evidence indicates that the cellular machinery controlling the splicing process (spliceosome) is altered in tumours, leading to oncogenic splicing events associated with tumour progression and aggressiveness. Here, we identify for the first time a profound dysregulation in the expression of relevant spliceosome components and splicing factors (at mRNA and protein levels) in well characterized cohorts of human high-grade astrocytomas, mostly glioblastomas, compared to healthy brain control samples, being SRSF3, RBM22, PTBP1 and RBM3 able to perfectly discriminate between tumours and control samples, and between proneural-like or mesenchymal-like tumours versus control samples from different mouse models with gliomas. Results were confirmed in four additional and independent human cohorts. Silencing of SRSF3, RBM22, PTBP1 and RBM3 decreased aggressiveness parameters in vitro (e.g. proliferation, migration, tumorsphere-formation, etc.) and induced apoptosis, especially SRSF3. Remarkably, SRSF3 was correlated with patient survival and relevant tumour markers, and its silencing in vivo drastically decreased tumour development and progression, likely through a molecular/cellular mechanism involving PDGFRB and associated oncogenic signalling pathways (PI3K-AKT/ERK), which may also involve the distinct alteration of alternative splicing events of specific transcription factors controlling PDGFRB (i.e. TP73). Altogether, our results demonstrate a drastic splicing machinery-associated molecular dysregulation in glioblastomas, which could potentially be considered as a source of novel diagnostic and prognostic biomarkers as well as therapeutic targets for glioblastomas. Remarkably, SRSF3 is directly associated with glioblastoma development, progression, aggressiveness and patient survival and represents a novel potential therapeutic target to tackle this devastating pathology.

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P11.17 Splicing dysregulation drives glioblastoma malignancy: SRSF3 as a potential therapeutic target to impair glioblastoma progression

Neuro-Oncology ◽

10.1093/neuonc/noz126.163 ◽

2019 ◽

Vol 21 (Supplement_3) ◽

pp. iii46-iii46

Author(s):

A C Fuentes-Fayos ◽

M C Vázquez-Borrego ◽

J M Jiménez-Vacas ◽

L Bejarano ◽

C Blanco-Acevedo ◽

...

Keyword(s):

Therapeutic Target ◽

Tumor Development ◽

Microarray Dataset ◽

Oncogenic Signaling ◽

Potential Therapeutic Target ◽

Induced Apoptosis ◽

Perfect Discrimination ◽

Control Samples

Abstract Glioblastomas (GBMs) remain the deadliest human brain tumors, with poor prognosis despite years of research. Currently, standard therapeutic strategies to treat GBM are not efficient and common survival from diagnosis is ~12–16 months. Thus, identification of new diagnostic/prognostic/therapeutic tools to tackle GBMs is crucial. Emerging evidence indicates that the cellular machinery controlling alternative splicing is altered in tumor pathologies, leading to oncogenic splicing events linked to tumor progression. Accordingly, we aimed to determine the expression pattern of the spliceosome components (SCs) and splicing factors (SFs) in high-grade astrocytomas (HGAs), mostly GBMs, and to ascertain the potential consequences of its dysregulation on GBM development. To this end, expression levels of SCs core and selected SFs were measured using a customized-microfluidic qPCR array in a well-characterized cohort of HGAs (n=33). Our results unveiled a profound alteration in the expression of multiple SCs and SFs in HGAs compared to healthy brain control-samples, wherein levels of particular elements (SRSF3/RBM22/PTBP1/RBM3) enabled perfect discrimination between non-pathological vs. tumor human-tissues, and between proneural and mesenchymal-like GBMs vs. control samples in mouse-models. Results were confirmed in an independent validation-cohort (n=49) and available Microarray dataset (Murat), which revealed that the expression of these splicing elements was correlated with relevant tumor markers and with survival. Remarkably, SRSF3/RBM22/PTBP1/RBM3 silencing (using specific siRNAs) decreased several aggressiveness parameters in vitro (e.g. proliferation, migration, tumorsphere formation, VEGFA secretion, etc.) and induced apoptosis, being SRSF3 the most relevant element affecting these parameters. Hence, a preclinical mouse model (U87MG-xenografts) with SRSF3 silencing drastically decreased in vivo tumor development/progression (i.e. tumor size, %MKI67, mitosis number, etc.) likely through a molecular/cellular mechanism involving the regulation of PDGFRB expression and its associated oncogenic signaling pathways. Overall, our results demonstrate that there is a profound dysregulation of the splicing machinery (spliceosome core and SFs) in HGAs/GBMs, which is directly associated to the development/progression of GBMs. Furthermore, this study reveals that SRSF3 can be a novel biomarker of malignancy and a potential therapeutic target to impair GBMs progression.

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Casticin Induced Apoptosis in A375.S2 Human Melanoma Cells through the Inhibition of NF-κB and Mitochondria-Dependent Pathways In Vitro and Inhibited Human Melanoma Xenografts in a Mouse Model In Vivo

The American Journal of Chinese Medicine ◽

10.1142/s0192415x1650035x ◽

2016 ◽

Vol 44 (03) ◽

pp. 637-661 ◽

Cited By ~ 13

Author(s):

Yin-Wen Shiue ◽

Chi-Cheng Lu ◽

Yu-Ping Hsiao ◽

Ching-Lung Liao ◽

Jing-Pin Lin ◽

...

Keyword(s):

Human Melanoma ◽

Oxygen Species ◽

Protein Levels ◽

Phase Arrest ◽

Viable Cells ◽

M Phase ◽

Induced Apoptosis ◽

Western Blotting Assay

Casticin, a polymethoxyflavone occurring in natural plants, has been shown to have anticancer activities. In the present study, we aims to investigate the anti-skin cancer activity of casticin on melanoma cells in vitro and the antitumor effect of casticin on human melanoma xenografts in nu/nu mice in vivo. A flow cytometric assay was performed to detect expression of viable cells, cell cycles, reactive oxygen species production, levels of [Formula: see text] and caspase activity. A Western blotting assay and confocal laser microscope examination were performed to detect expression of protein levels. In the in vitro studies, we found that casticin induced morphological cell changes and DNA condensation and damage, decreased the total viable cells, and induced G2/M phase arrest. Casticin promoted reactive oxygen species (ROS) production, decreased the level of [Formula: see text], and promoted caspase-3 activities in A375.S2 cells. The induced G2/M phase arrest indicated by the Western blotting assay showed that casticin promoted the expression of p53, p21 and CHK-1 proteins and inhibited the protein levels of Cdc25c, CDK-1, Cyclin A and B. The casticin-induced apoptosis indicated that casticin promoted pro-apoptotic proteins but inhibited anti-apoptotic proteins. These findings also were confirmed by the fact that casticin promoted the release of AIF and Endo G from mitochondria to cytosol. An electrophoretic mobility shift assay (EMSA) assay showed that casticin inhibited the NF-[Formula: see text]B binding DNA and that these effects were time-dependent. In the in vivo studies, results from immuno-deficient nu/nu mice bearing the A375.S2 tumor xenograft indicated that casticin significantly suppressed tumor growth based on tumor size and weight decreases. Early G2/M arrest and mitochondria-dependent signaling contributed to the apoptotic A375.S2 cell demise induced by casticin. In in vivo experiments, A375.S2 also efficaciously suppressed tumor volume in a xenotransplantation model. Therefore, casticin might be a potential therapeutic agent for the treatment of skin cancer in the future.

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PIDDosome Expression and the Role of Caspase-2 Activation for Chemotherapy-Induced Apoptosis in RCCs

Analytical Cellular Pathology ◽

10.1155/2010/803824 ◽

2010 ◽

Vol 32 (1-2) ◽

pp. 29-42

Author(s):

Sebastian Heikaus ◽

Igor Pejin ◽

Helmut Erich Gabbert ◽

Uwe Ramp ◽

Csaba Mahotka

Keyword(s):

Tumour Progression ◽

Chemotherapy Resistance ◽

Clear Cell Type ◽

Alternatively Spliced ◽

Caspase 2 ◽

Induced Apoptosis ◽

Few Data

Background: The importance of caspase-2 activation for mediating apoptosis in cancer is not clear and seems to differ between different tumour types. Furthermore, only few data have been obtained concerning the expression of caspase-2, which can be alternatively spliced into caspase-2L and caspase-2S, and the other PIDDosome members PIDD and RAIDD in human tumours in vivo. We, therefore, investigated their expression in renal cell carcinomas (RCCs) of the clear cell type in vivo and analysed the role of caspase-2 in chemotherapy-induced apoptosis in RCCs in vitro.Methods: The analyses were performed by semiquantitative real-time PCR, Western Blot and Caspase-2 Assay.Results: Our in vivo results showed an overall decrease in proapoptotic caspase-2L expression during tumour progression due to an increase in the relative share of caspase-2S mRNA in total caspase-2 mRNA expression. Furthermore, an increase in the expression of PIDD and RAIDD could be observed. In contrast, antiapoptotic BCL-2 expression increased only during early tumour stages, whereas expression decreased in pT3 RCCs. In vitro, caspase-2 activation in RCC cell lines coincidenced with sensitivity of tumour cells towards Topotecan-induced apoptosis. However, inhibition of caspase-2 could not prevent Topotecan-induced apoptosis. Interestingly, Topotecan-resistance could be overcome by the apoptosis-sensitizing drug HA14-1.Conclusions: Our study confirms the concept of a shift towards a more antiapoptotic transcriptional context during tumour progression in RCCs. Furthermore, it shows that caspase-2 participates in chemotherapy-induced apoptosis in RCCs although it is not mandatory for it. Additionally, inhibition of antiapoptotic BCL-2 family members might provide a possible way to overcome chemotherapy resistance of RCCs.

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Phospholipase D1 Ameliorates Apoptosis in Chronic Renal Toxicity Caused by Low-Dose Cadmium Exposure

BioMed Research International ◽

10.1155/2020/7091053 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Ke Huang ◽

Yaotang Deng ◽

Wenya Yuan ◽

Jian Geng ◽

Guanghai Wang ◽

...

Keyword(s):

Molecular Mechanisms ◽

Kidney Tissue ◽

Kidney Injury ◽

Sprague Dawley ◽

Protein Levels ◽

Phospholipase D1 ◽

Induced Apoptosis ◽

Kidney Impairment

Exposure to cadmium (Cd), a common heavy metal used in industry, can result in long-term chronic toxicity. It has been well characterized that kidneys are the main organs that are targeted by toxicity, which can cause apoptosis, necrosis, and atrophy of renal tubular epithelial cells. However, the molecular mechanisms associated with Cd toxicity remain unclear. In this study, the expression of renal proteins in Sprague-Dawley rats exposed to chronic Cd was analyzed with iTRAQ proteomics. Bioinformatics analysis indicated that phospholipase D1 (PLD1) was significantly underexpressed and may correlate strongly with Cd-induced chronic kidney impairment. Previous studies have shown that PLD1 promotes cell proliferation and inhibits apoptosis, indicating that PLD1 may be implicated in the pathogenesis of kidney injury induced by Cd. Studies in vivo and in vitro all demonstrate that the mRNA and protein levels of PLD1 decrease significantly both in kidney tissue and in proximal tubular cell lines exposed to Cd. Overexpression of PLD1 and its downstream product PA could ameliorate Cd-induced apoptosis. Moreover, we identified that miR-122-5p was a regulatory miRNA of PLD1. miR-122-5p was overexpressed after Cd exposure and promoted cell apoptosis by downregulating PLD1 through binding the 3′UTR of the locus at 1761–1784 nt. In conclusion, our results indicated that PLD1 and its downstream PA were strongly implicated in Cd-induced chronic kidney impairment and could be a novel player in the defense against Cd-induced nephrotoxicity.

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Anticancer Properties and Mechanisms of Singly-Protonated Dehydronorcantharidin Silver Coordination Polymer in a Bladder Cancer Model

Frontiers in Pharmacology ◽

10.3389/fphar.2021.618668 ◽

2021 ◽

Vol 12 ◽

Author(s):

Changkuo Zhou ◽

Ganyu Wang ◽

Weiqiang Jing ◽

Xuejie Tan ◽

Hu Guo

Keyword(s):

Bladder Cancer ◽

Protein Levels ◽

Anticancer Properties ◽

G1 Phase Arrest ◽

Bladder Cancer Cells ◽

System Tumor ◽

Induced Apoptosis ◽

Effective Drugs

Bladder cancer is the most common malignant urinary system tumor. Chemotherapy is frequently used as a treatment regimen for patients with bladder cancer, however, new and effective drugs for bladder cancer need to be developed. The present study examined the effects and mechanisms of Ag-SP-DNC, a silver and singly-protonated dehydronorcantharidin complex, on bladder cancer in vitro and in vivo. It was identified that Ag-SP-DNC suppressed cell proliferation and induced apoptosis in bladder cancer cells in vitro, a suppression associated with G0/G1 phase arrest and elevated intracellular reactive oxygen species (ROS) levels. Furthermore, Ag-SP-DNC enhanced the cleaved caspase-3 levels, disrupted the mitochondrial transmembrane potential balance, and induced intracellular calcium overload. The Ag-SP-DNC-induced bladder cancer cell apoptosis was significantly decreased following treatment with a broad caspase inhibitor, zVAD-fmk. In addition, treatment of MB49 tumor-bearing mice with Ag-SP-DNC significantly inhibited tumor growth and decreased the anti-apoptosis and cell cycle promotion protein levels in the tumor. The results of the present study suggested that Ag-SP-DNC elicits a strong anticancer effect against bladder cancer, and can therefore be used as a promising treatment for bladder cancer.

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A Regulatory Loop of FBXW7-MYC-PLK1 Controls Tumorigenesis of MYC-Driven Medulloblastoma

Cancers ◽

10.3390/cancers13030387 ◽

2021 ◽

Vol 13 (3) ◽

pp. 387

Author(s):

Dong Wang ◽

Angela Pierce ◽

Bethany Veo ◽

Susan Fosmire ◽

Etienne Danis ◽

...

Keyword(s):

Tumor Development ◽

Tumor Suppressor Function ◽

Protein Levels ◽

Group 3 ◽

Induced Apoptosis ◽

Regulatory Loop ◽

Proliferation In Vitro ◽

Constitutive Phosphorylation

Polo-like kinase 1 (PLK1) is highly expressed in group 3 medulloblastoma (MB), and it has been preclinically validated as a cancer therapeutic target in medulloblastoma. Here, we demonstrate that PLK1 inhibition with PCM-075 or BI6727 significantly reduces the growth of MB cells and causes a decrease of c-MYC mRNA and protein levels. We show that MYC activates PLK1 transcription, while the inhibition of PLK1 suppresses MB tumor development and causes a decrease in c-MYC protein level by suppressing FBXW7 auto poly-ubiquitination. FBXW7 physically interacts with PLK1 and c-MYC, facilitating their protein degradation by promoting ubiquitination. These results demonstrate a PLK1-FBXW7-MYC regulatory loop in MYC-driven medulloblastoma. Moreover, FBXW7 is significantly downregulated in group 3 patient samples. The overexpression of FBXW7 induced apoptosis and suppressed proliferation in vitro and in vivo, while constitutive phosphorylation mutation attenuated its tumor suppressor function. Altogether, these findings demonstrated that PLK1 inhibition stabilizes FBXW7 in MYC-driven MB, thus revealing an important function of FBXW7 in suppressing medulloblastoma progression.

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All-Trans Retinoic Acid Increases DRP1 Levels and Promotes Mitochondrial Fission

Cells ◽

10.3390/cells10051202 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1202

Author(s):

Bojjibabu Chidipi ◽

Syed Islamuddin Shah ◽

Michelle Reiser ◽

Manasa Kanithi ◽

Amanda Garces ◽

...

Keyword(s):

Retinoic Acid ◽

Mitochondrial Fission ◽

Normal Function ◽

Mitochondrial Network ◽

Protein Levels ◽

Trans Retinoic Acid ◽

All Trans Retinoic Acid ◽

Area And Perimeter

In the heart, mitochondrial homeostasis is critical for sustaining normal function and optimal responses to metabolic and environmental stressors. Mitochondrial fusion and fission are thought to be necessary for maintaining a robust population of mitochondria, and disruptions in mitochondrial fission and/or fusion can lead to cellular dysfunction. The dynamin-related protein (DRP1) is an important mediator of mitochondrial fission. In this study, we investigated the direct effects of the micronutrient retinoid all-trans retinoic acid (ATRA) on the mitochondrial structure in vivo and in vitro using Western blot, confocal, and transmission electron microscopy, as well as mitochondrial network quantification using stochastic modeling. Our results showed that ATRA increases DRP1 protein levels, increases the localization of DRP1 to mitochondria in isolated mitochondrial preparations. Our results also suggested that ATRA remodels the mitochondrial ultrastructure where the mitochondrial area and perimeter were decreased and the circularity was increased. Microscopically, mitochondrial network remodeling is driven by an increased rate of fission over fusion events in ATRA, as suggested by our numerical modeling. In conclusion, ATRA results in a pharmacologically mediated increase in the DRP1 protein. It also results in the modulation of cardiac mitochondria by promoting fission events, altering the mitochondrial network, and modifying the ultrastructure of mitochondria in the heart.

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TRIM27 interacts with Iκbα to promote the growth of human renal cancer cells through regulating the NF-κB pathway

BMC Cancer ◽

10.1186/s12885-021-08562-5 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Chengwu Xiao ◽

Wei Zhang ◽

Meimian Hua ◽

Huan Chen ◽

Bin Yang ◽

...

Keyword(s):

Cell Lines ◽

Prognostic Indicator ◽

The Cancer Genome Atlas ◽

Mrna Levels ◽

Loss Of Function ◽

Protein Levels ◽

Kaplan Meier ◽

Cancer Genome Atlas

Abstract Background The tripartite motif (TRIM) family proteins exhibit oncogenic roles in various cancers. The roles of TRIM27, a member of the TRIM super family, in renal cell carcinoma (RCC) remained unexplored. In the current study, we aimed to investigate the clinical impact and roles of TRIM27 in the development of RCC. Methods The mRNA levels of TRIM27 and Kaplan–Meier survival of RCC were analyzed from The Cancer Genome Atlas database. Real-time PCR and Western blotting were used to measure the mRNA and protein levels of TRIM27 both in vivo and in vitro. siRNA and TRIM27 were exogenously overexpressed in RCC cell lines to manipulate TRIM27 expression. Results We discovered that TRIM27 was elevated in RCC patients, and the expression of TRIM27 was closely correlated with poor prognosis. The loss of function and gain of function results illustrated that TRIM27 promotes cell proliferation and inhibits apoptosis in RCC cell lines. Furthermore, TRIM27 expression was positively associated with NF-κB expression in patients with RCC. Blocking the activity of NF-κB attenuated the TRIM27-mediated enhancement of proliferation and inhibition of apoptosis. TRIM27 directly interacted with Iκbα, an inhibitor of NF-κB, to promote its ubiquitination, and the inhibitory effects of TRIM27 on Iκbα led to NF-κB activation. Conclusions Our results suggest that TRIM27 exhibits an oncogenic role in RCC by regulating NF-κB signaling. TRIM27 serves as a specific prognostic indicator for RCC, and strategies targeting the suppression of TRIM27 function may shed light on future therapeutic approaches.

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Plant-Derived Nano and Microvesicles for Human Health and Therapeutic Potential in Nanomedicine

Pharmaceutics ◽

10.3390/pharmaceutics13040498 ◽

2021 ◽

Vol 13 (4) ◽

pp. 498

Author(s):

Mariaevelina Alfieri ◽

Antonietta Leone ◽

Alfredo Ambrosone

Keyword(s):

Therapeutic Potential ◽

Biological Activities ◽

Plant Biotechnology ◽

Bioactive Metabolites ◽

Anticancer Activities ◽

Long Distance ◽

In Vivo Models ◽

Therapeutic Tools

Plants produce different types of nano and micro-sized vesicles. Observed for the first time in the 60s, plant nano and microvesicles (PDVs) and their biological role have been inexplicably under investigated for a long time. Proteomic and metabolomic approaches revealed that PDVs carry numerous proteins with antifungal and antimicrobial activity, as well as bioactive metabolites with high pharmaceutical interest. PDVs have also been shown to be also involved in the intercellular transfer of small non-coding RNAs such as microRNAs, suggesting fascinating mechanisms of long-distance gene regulation and horizontal transfer of regulatory RNAs and inter-kingdom communications. High loading capacity, intrinsic biological activities, biocompatibility, and easy permeabilization in cell compartments make plant-derived vesicles excellent natural or bioengineered nanotools for biomedical applications. Growing evidence indicates that PDVs may exert anti-inflammatory, anti-oxidant, and anticancer activities in different in vitro and in vivo models. In addition, clinical trials are currently in progress to test the effectiveness of plant EVs in reducing insulin resistance and in preventing side effects of chemotherapy treatments. In this review, we concisely introduce PDVs, discuss shortly their most important biological and physiological roles in plants and provide clues on the use and the bioengineering of plant nano and microvesicles to develop innovative therapeutic tools in nanomedicine, able to encompass the current drawbacks in the delivery systems in nutraceutical and pharmaceutical technology. Finally, we predict that the advent of intense research efforts on PDVs may disclose new frontiers in plant biotechnology applied to nanomedicine.

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Long noncoding RNA SNHG14 promotes hepatocellular carcinoma progression by regulating miR-876-5p/SSR2 axis

Journal of Experimental & Clinical Cancer Research ◽

10.1186/s13046-021-01838-5 ◽

2021 ◽

Vol 40 (1) ◽

Author(s):

Zhibin Liao ◽

Hongwei Zhang ◽

Chen Su ◽

Furong Liu ◽

Yachong Liu ◽

...

Keyword(s):

Noncoding Rna ◽

Animal Experiments ◽

Luciferase Reporter ◽

Western Blot Assay ◽

Downstream Target ◽

Protein Levels ◽

Elevated Expression ◽

Rna Immunoprecipitation

Abstract Background Aberrant expressions of long noncoding RNAs (lncRNAs) have been demonstrated to be related to the progress of HCC. The mechanisms that SNHG14 has participated in the development of HCC are obscure. Methods Quantitative real-time PCR (qRT-PCR) was used to measure the lncRNA, microRNA and mRNA expression level. Cell migration, invasion and proliferation ability were evaluated by transwell and CCK8 assays. The ceRNA regulatory mechanism of SNHG14 was evaluated by RNA immunoprecipitation (RIP) and dual luciferase reporter assay. Tumorigenesis mouse model was used to explore the roles of miR-876-5p in vivo. The protein levels of SSR2 were measured by western blot assay. Results In this study, we demonstrated that SNHG14 was highly expressed in HCC tissues, meanwhile, the elevated expression of SNHG14 predicted poor prognosis in patients with HCC. SNHG14 promoted proliferation and metastasis of HCC cells. We further revealed that SNHG14 functioned as a competing endogenous RNA (ceRNA) for miR-876-5p and that SSR2 was a downstream target of miR-876-5p in HCC. Transwell, CCK8 and animal experiments exhibited miR-876-5p inhibited HCC progression in vitro and in vivo. By conducting rescue experiments, we found the overexpression of SSR2 or knocking down the level of miR-876-5p could reverse the suppressive roles of SNHG14 depletion in HCC. Conclusion SNHG14 promotes HCC progress by acting as a sponge of miR-876-5p to regulate the expression of SSR2 in HCC.

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