Expression Of G3BP1 Research Articles

G3BP2 promotes tumor progression and gemcitabine resistance in PDAC via regulating PDIA3-DKC1-hENT in a stress granules-dependent manner.

Pancreatic ductal adenocarcinoma (PDAC) is distinguished by its aggressive malignancy, limited treatment avenues and a tendency towards chemotherapy resistance, underscoring the critical need for advanced research to uncover new therapeutic approaches. Stress granules (SGs) that is implicated in cellular self-protection mechanism, along with its associated family molecules have shown pro-cancer effects and are closely related to tumor chemotherapy resistance. In this study we investigated the relationship between Ras GTPase-activating protein-binding proteins 2 (G3BP2), a core component of SGs, and the malignancy of PDAC as well as its resistance to the chemotherapy drug gemcitabine. Analyzing TCGA dataset revealed that the expression of G3BP1 and G3BP2 was significantly upregulated in PDAC compared with adjacent normal pancreatic tissues, and the high expression of G3BP2 rather than G3BP1 was significantly associated with poorer overall survival (OS) in PDAC patients. We demonstrated that knockdown of G3BP2 inhibited the proliferation and invasion of PANC-1 and CFPAC-1 cells in vitro and in vivo. By analyzing the differentially expressed genes in G3BP2 knockdown and overexpressed PANC-1 cells, we identified DKC1 that was associated with RNA stability and regulation as the target of G3BP2. We demonstrated that G3BP2 bound to PDIA3 mRNA and recruited them into SGs, increasing the stability of PDIA3 mRNA and attenuating its translation efficiency, thereby promoting DKC1 expression. Furthermore, DKC1 could bind to hENT mRNA and inhibited its expression, which enhanced gemcitabine resistance of PDAC. Therefore, we propose a novel mechanism wherein G3BP2 facilitates PDAC's resistance to chemotherapy by modulating PDIA3-DKC1-hENT in a SGs-dependent way, suggesting G3BP2 SGs a protentional therapeutic target for the treatment in PDAC.

Critical role of G3BP1 in bovine parainfluenza virus type 3 (BPIV3)-inhibition of stress granules formation and viral replication.

It remains unclear whether BPIV3 infection leads to stress granules formation and whether G3BP1 plays a role in this process and in viral replication. This study aims to clarify the association between BPIV3 and stress granules, explore the effect of G3BP1 on BPIV3 replication, and provide significant insights into the mechanisms by which BPIV3 evades the host's antiviral immunity to support its own survival. Here, we use Immunofluorescence staining to observe the effect of BPIV3 infection on the assembly of stress granules. Meanwhile, the expression changes of eIF2α and G3BP1 were determined. Overexpression or siRNA silencing of intracellular G3BP1 levels was examined for its regulatory control of BPIV3 replication. We identify that the BPIV3 infection elicited phosphorylation of the eIF2α protein. However, it did not induce the assembly of stress granules; rather, it inhibited the formation of stress granules and downregulated the expression of G3BP1. G3BP1 overexpression facilitated the formation of stress granules within cells and hindered viral replication, while G3BP1 knockdown enhanced BPIV3 expression. This study suggest that G3BP1 plays a crucial role in BPIV3 suppressing stress granule formation and viral replication.

Evaluation of G3BP1 in the prognosis of acute and acute-on-chronic liver failure after the treatment of artificial liver support system.

The increased expression of G3BP1 was positively correlated with the prognosis of liver failure. To investigate the effect of G3BP1 on the prognosis of acute liver failure (ALF) and acute-on-chronic liver failure (ACLF) after the treatment of artificial liver support system (ALSS). A total of 244 patients with ALF and ACLF were enrolled in this study. The levels of G3BP1 on admission and at discharge were detected. The validation set of 514 patients was collected to verify the predicted effect of G3BP1 and the viability of prognosis. This study was shown that lactate dehydrogenase (LDH), alpha-fetoprotein (AFP) and prothrombin time were closely related to the prognosis of patients. After the ALSS treatment, the patient' amount of decreased G3BP1 index in difference of G3BP1 between the value of discharge and admission (difG3BP1) < 0 group had a nearly 10-fold increased risk of progression compared with the amount of increased G3BP1 index. The subgroup analysis showed that the difG3BP1 < 0 group had a higher risk of progression, regardless of model for end-stage liver disease high-risk or low-risk group. At the same time, compared with the inflammatory marks [tumor necrosis factor-α, interleukin (IL)-1β and IL-18], G3BP1 had higher discrimination and was more stable in the model analysis and validation set. When combined with AFP and LDH, concordance index was respectively 0.84 and 0.8 in training and validation cohorts. This study indicated that G3BP1 could predict the prognosis of ALF or ACLF patients treated with ALSS. The combination of G3BP1, AFP and LDH could accurately evaluate the disease condition and predict the clinical endpoint of patients.

The Role of G3BP1 Gene Mediates P38 MAPK/JNK Pathway in Testicular Spermatogenic Dysfunction Caused by Cyfluthrin.

In recent years, male infertility has received global attention and seriously affected the quality of human fertility, and pyrethroids (type II pyrethroids), as recognized environmental endocrine disruptors, may threaten male reproductive health. Therefore, in this study, we established an in vivo model for the development of testicular and germ cell toxicity induced by cyfluthrin and explored the role and mechanism of the G3BP1 gene-mediated P38 MAPK/JNK pathway in testicular and germ cell damage caused by cyfluthrin to find early and sensitive indicators and new therapeutic targets for the development of testicular damage. Firstly, 40 male Wistar rats (about 260 g) were divided into a control group (corn oil), low dose group (6.25 mg/kg), middle dose group (12.5 mg/kg) and high dose group (25 mg/kg). The rats were anesthetized and executed after 28 days of poisoning on alternate days. Then, HE staining, transmission electron microscopy, ELISA, q-PCR, Western blot, immunohistochemistry, double-immunofluorescence and TUNEL were used to observe the pathology, androgen levels, oxidative damage and altered expression of the key factors of the G3BP1 and MAPK pathways in rat testes. The results showed that, compared with the control group, the testicular tissue and spermatocytes were superficially damaged with an increasing dose of cyfluthrin; furthermore, it could interfere with the normal secretion of the hypothalamic-pituitary-gonadal axis (serum GnRH, FSH, T and LH levels) and cause hypergonadal dysfunction. A dose-dependent increase in MDA and a dose-dependent decrease in T-AOC indicated that the oxidative-antioxidative homeostatic balance was disrupted. The Western blot and qPCR analysis revealed that G3BP1, p-JNK1/2/3, P38 MAPK, p-ERK, COX1 and COX4 proteins and mRNA expression were decreased, and p-JNK1/2/3, p-P38MAPK, caspase 3/8/9 proteins and mRNA expression were significantly increased. The double-immunofluorescence and immunohistochemistry results showed that the protein expression of G3BP1 decreased with an increasing dose of staining, while the expression of JNK1/2/3 and P38 MAPK were increased significantly. The positive expressions of G3BP1 were mainly located in the testicular germinal epithelium and germ cell layer, and the positive expressions of JNK1/2/3 were mainly located in the testicular germinal epithelium and sperm cells, while the positive expressions of P38 MAPK were located in all levels of the germ cells and spermatozoa. Our results demonstrated that exposure to cyfluthrin caused testicular and spermatocyte damage in rats, which could cause pathomorphology, altered androgen levels and a decreased antioxidant capacity. When the intracellular antioxidant capacity was impaired, G3BP1 expression and activity were inhibited, causing activation of the P38 MAPK/JNK pathway and activation of the intracellular apoptotic pathway, which, in turn, led to germ cell apoptosis.

LIMK2 promotes melanoma tumor growth and metastasis through G3BP1-ESM1 pathway-mediated apoptosis inhibition.

Melanoma is the leading cause of skin cancer-related deaths, and current melanoma therapies, including targeted therapies and immunotherapies, benefit only a subset of metastatic melanoma patients due to either intrinsic or acquired resistance. LIM domain kinase 2 (LIMK2) is a serine/threonine kinase that plays an important role in the regulation of actin filament dynamics. Here, we show that LIMK2 is overexpressed in melanoma, and its genetic or pharmacological inhibition impairs melanoma tumor growth and metastasis in both cell culture and mice. To determine the mechanism by which LIMK2 promotes melanoma tumor growth and metastatic progression, we performed a phosphoproteomics analysis and identified G3BP1 as a key LIMK2 target, which mirrored the effects of LIMK2 inhibition when inhibited. To further determine the role of G3BP1 downstream of LIMK2, we knocked down the expression of G3BP1, performed RNA-seq analysis, and identified ESM1 as a downstream target of G3BP1. G3BP1 was required for ESM1 mRNA stability, and ESM1 ectopic expression rescued LIMK2 or G3BP1 inhibition-induced suppression of melanoma growth and metastatic attributes. These results collectively identify the LIMK2→G3BP1→ESM1 pathway as a facilitator of melanoma tumor growth and metastasis and document that LIMK2 is a therapeutically tractable target for melanoma therapy.

Tumor-Associated Macrophages Promote Metastasis of Oral Squamous Cell Carcinoma via CCL13 Regulated by Stress Granule.

M2 tumor-associated macrophages (TAMs) have been a well-established promoter of oral squamous cell carcinoma (OSCC) progression. However, the mechanisms of M2 TAMs promoting OSCC metastasis have not been elucidated clearly. This study illustrated the regulatory mechanisms in which M2 TAMs enhance OSCC malignancy in a novel point of view. In this study, mass spectrometry was utilized to analyze the proteins expression profile of M2 type monocyte-derived macrophages (MDMs-M2), whose results revealed the high expression of G3BP1 in M2 macrophages. RNA sequencing analyzed the genome-wide changes upon G3BP1 knockdown in MDMs-M2 and identified that CCL13 was the most significantly downregulated inflammatory cytokines in MDMs-M2. Co-immunoprecipitation and qualitative mass spectrometry were used to identify the proteins that directly interacted with endogenous G3BP1 in MDMs-M2. Elevated stress granule (SG) formation in stressed M2 TAMs enhanced the expression of CCL13, which promoted OSCC metastasis both in vitro and in vivo. For mechanisms, we demonstrated SG formation improved DDX3Y/hnRNPF-mediated CCL13 mRNA stability, thus enhancing CCL13 expression and promoting OSCC metastasis. Collectively, our findings demonstrated for the first time the roles of CCL13 in improving OSCC metastasis and illustrated the molecular mechanisms of CCL13 expression regulated by SG, indicating that the SG-CCL13 axis can be the potential targets for TAM-navigated tumor therapy.

Phillygenin activates PKR/eIF2α pathway and induces stress granule to exert anti-avian infectious bronchitis virus

The prevalence of avian infectious bronchitis virus (IBV) is still one of causes inducing severe losses of production in the poultry industry worldwide. Vaccination does not completely prevent IBV infection and spread due to immune failure and viral mutations. ForsythiaeFructus and its compounds have been widely used in a lot of prescriptions of the traditional Chinese medicine for a long history, and it is well-known as safety and efficiency in heat-clearing and detoxifying. This study aims to investigate the anti-IBV activity and mechanism of phillygenin. The results showed that phillygenin inhibited IBV replication by disturbing multiple stages of the virus life cycle, including viral adsorption, invasion, internalization, and release in Vero cells. After being treated with 100, 125 and 150 μg/mL phillygenin, the expression of G3BP1 was significantly increased and the phosphorylation of PKR/eIF2α was activated, which increased stress granule, thereby triggering the antiviral response in Vero cells. The anti-virus activity of PHI was decreased when G3BP1 was interfered by si-RNA, and G3BP1 was down-regulated when PKR/eIF2α was interfered by si-RNA. In conclusion, our findings indicate that phillygenin activates PKR/eIF2α pathway and induces stress granule formation to exert anti-IBV, which holds promise to develop into a novel anti-IBV drug. Further study in vivo is needed to explore phillygenin as a potential and effective drug to prevent IB in poultry.

Genomics-guided targeting of stress granule proteins G3BP1/2 to inhibit SARS-CoV-2 propagation

SARS-CoV-2 nucleocapsid (N) protein undergoes RNA-induced phase separation (LLPS) and sequesters the host key stress granule (SG) proteins, Ras-GTPase-activating protein SH3-domain-binding protein 1 and 2 (G3BP1 and G3BP2) to inhibit SG formation. This will allow viral packaging and propagation in host cells. Based on a genomic-guided meta-analysis, here we identify upstream regulatory elements modulating the expression of G3BP1 and G3BP2 (collectively called G3BP1/2). Using this strategy, we have identified FOXA1, YY1, SYK, E2F-1, and TGFBR2 as activators and SIN3A, SRF, and AKT-1 as repressors of G3BP1/2 genes. Panels of the activators and repressors were then used to identify drugs that change their gene expression signatures. Two drugs, imatinib, and decitabine have been identified as putative modulators of G3BP1/2 genes and their regulators, suggesting their role as COVID-19 mitigation agents. Molecular docking analysis suggests that both drugs bind to G3BP1/2 with a much higher affinity than the SARS-CoV-2 N protein. This study reports imatinib and decitabine as candidate drugs against N protein and G3BP1/2 protein.

SILAC-based quantitative MS approach reveals Withaferin A regulated proteins in prostate cancer

Withaferin A (WA) is a steroidal lactone extracted from Withania somnifera, commonly known as Ashwagandha. WA has several therapeutic benefits. The current study aims to identify proteins that are potentially regulated by WA in prostate cancer (PCA) cells. We used a SILAC-based proteomic approach to analyze the expression of proteins in response to WA treatment at 4 h and 24 h time points in three PCA cell lines: 22Rv1, DU-145, and LNCaP. Ontology analysis suggested that prolonged treatment with WA upregulated the expression of proteins involved in stress-response pathways. Treatment with WA increased oxidative stress, reduced global mRNA translation, and elevated the expression of cytoprotective stress granule (SG) protein G3BP1. WA treatment also enhanced the formation of SGs. The elevated expression of G3BP1 and the formation of SGs might constitute a mechanism of cytoprotection in PCA cells. Knockdown of G3BP1 blocked SG formation and enhanced the efficacy of WA to reduce PCA cell survival. SignificanceWithaferin A, a steroidal lactone, extracted from Withania somnifera is a promising anti-cancer drug. Using a SILAC-based quantitative proteomic approach, we identified proteins changed by WA-treatment at 4 h and 24 h in three prostate cancer (PCA) cell lines. WA-treatment induced the expression of proteins involved in apoptosis and reduced the expression of proteins involved in cell growth at 4 h. WA-treatment for 24 h enhanced the expression of proteins involved in stress response pathways. WA-treated cells exhibited increased oxidative stress, reduced mRNA translation and enhanced SG formation. PCA is characterized by higher metabolic rate and increased oxidative stress. PCA with a higher stress tolerance can effectively adapt to anti-cancer treatment stress, leading to drug resistance and cellular protection. Enhancing the level of oxidative stress along with inhibition of corresponding cytoprotective stress response pathways is a feasible option to prevent PCA from getting adapted to treatment stress. WA-treatment induced oxidative stress, in combination with blocking SGs by G3BP1 targeting, offers a therapeutic strategy to reduce PCA cell survival.

G3BP1 may serve as a potential biomarker of proliferation, apoptosis, and prognosis in oral squamous cell carcinoma.

G3BP1 is a prognostic biomarker for many types of cancers; however, its role in oral squamous cell carcinoma remains unclear. We investigated the role of G3BP1 as a potential biomarker for proliferation, apoptosis, and prognosis in oral squamous cell carcinoma. We obtained samples of normal oral mucosa (n=17), oral squamous cell carcinoma tissues (n=61), and paired adjacent tissues (n=47) from Xiangya Hospital for immunohistochemical evaluation to measure the expression of G3BP1, E-cadherin, Ki67, and Cleaved-caspase3. Using data from The Cancer Genome Atlas, we performed bioinformatics analysis to investigate the prognosis, functions, signaling pathways, and immune infiltrate significance related to G3BP1 in oral squamous cell carcinoma. The G3BP1 protein level was significantly upregulated in oral squamous cell carcinoma tissues and was also positively associated with Ki67 and negatively associated with Cleaved-caspase3. Based on information available in online database, the G3BP1 mRNA level was significantly higher in oral squamous cell carcinoma than in normal tissues. High G3BP1 mRNA levels were associated with poor overall survival rates in patients with oral squamous cell carcinoma. Enrichment analysis showed that G3BP1 was involved in the helicase/catalytic/ATPase activity functions and spliceosome/RNA transport/ cell cycle pathways. Furthermore, G3BP1 mRNA levels were positively associated with CD4+ T-cell infiltration. G3BP1 may serve as a potential biomarker for proliferation, apoptosis, and prognosis of oral squamous cell carcinoma.

Expression of G3BP1 in benign and malignant human prostate tissues.

BackgroundProstate cancer (PCa) is the world’s leading type of cancer in men. GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) is overexpressed in a variety of tumors. However, there are limited studies in PCa concerning G3BP1. This present study was to investigates the expression of G3BP1 and the mechanism of action on PCa.MethodsWe explored the G3BP1 expression in PCa using the TCGA database and verified it using clinical samples by immunohistochemistry (IHC) methods. G3BP1 and Androgen receptor (AR) status of 104 human PCa and 50 benign prostate hyperplasia (BPH) samples were analyzed by IHC and the association between G3BP1 expression and biochemical recurrence was determined. Moreover, we generated G3BP1 knockdown cell lines in human PCa LNCaP cell lines, to observe AR changes.ResultsG3BP1 and AR were overexpressed in PCa compared to BPH tissues. The expression of G3BP1 and AR was positively correlated with the malignant degree of the tumor. Higher G3BP1 expression showed a trend toward biochemical recurrence. Western blot showed downregulation of G3BP1 affected AR expression levels.ConclusionsOur study suggested that G3BP1 was frequently upregulated in PCa and closely related to AR expression and tumor metastasis. Besides, G3BP1 might be associated with biochemical recurrence. These results supply potential target for the management of the PCa.

G3BP1 interacts with YWHAZ to regulate chemoresistance and predict adjuvant chemotherapy benefit in gastric cancer

BACKGROUNDA large proportion of gastric cancer patients are susceptible to chemoresistance, while the underlying mechanism remains obscure. Stress granules (SGs) play a self-defence role for tumour cells in inhibiting chemotherapy-induced apoptosis. As an SG assembly effector, G3BP1 (Ras-GTPase-activating protein SH3 domain-binding protein) has been reported to be overexpressed in gastric cancer; thus, here we aim to explore its potent roles in gastric cancer chemoresistance.METHODSKaplan–Meier analysis was used to compare survival rates in gastric cancer patients with different G3BP1 expression. The influence of G3BP1 on gastric cancer cell chemoresistance and apoptosis were evaluated by in vitro and in vivo approaches. The interaction between G3BP1 and YWHAZ was assessed by immunohistochemistry, immunoprecipitation and immunofluorescence.RESULTSG3BP1 was associated with the poor outcome of gastric cancer patients who received adjuvant chemotherapy. G3BP1 knockdown significantly increased the sensitivity of gastric cancer cells to chemotherapy drugs. Mechanically, cell apoptosis and pro-apoptotic-associated molecules were significantly elevated upon G3BP1 depletion. Gene co-expression network analyses identified YWHAZ as the critical interlayer of G3BP1; as a result, G3BP1 interacted with YWHAZ to sequester Bax into the cytoplasm. Clinically, G3BP1highYWHAZhigh gastric cancer patients displayed the worst outcome compared with other patients after chemotherapy.CONCLUSIONSThe expression of G3BP1 and YWHAZ could predict the adjuvant chemotherapy benefit in gastric cancer patients.

Overexpression of G3BP1 facilitates the progression of colon cancer by activating β‑catenin signaling.

Ras-GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) has been reported to be of importance in the occurrence and development of colon cancer. However, the underlying mechanisms remain largely unknown. Therefore, the aim of the present study was to investigate the role of Wnt/β-catenin signaling in G3BP1-mediated colon cancer progression. The expression of G3BP1 in colon tissues and cells was detected via reverse transcription-quantitative PCR, western blotting and immunohistochemistry. Gain-of-function assays were performed in colon cancer RKO cells, which have a relatively low expression of G3BP1, while loss-of-function assays were performed in SW620 colon cancer cells, which have a relatively high expression of G3BP1. Cell proliferation, apoptosis and tumorigenesis were assessed using Cell Counting Kit-8, flow cytometry and tumor-bearing mice assays, respectively. The results demonstrated that G3BP1 expression was significantly upregulated in colon cancer tissues and cells compared with healthy colon tissues and cells. It was found that high expression of G3BP1 was closely associated with the poor prognosis and advanced clinical process in patients with colon cancer. Overexpression of G3BP1 in RKO cells enhanced their proliferative ability and decreased their apoptosis tendency, while knockdown of G3BP1 inhibited SW620 cell proliferation and induced apoptosis. In addition, G3BP1 interacted with β-catenin and upregulated its expression and nuclear accumulation. It was identified that β-catenin knockdown abolished the effects of G3BP1 on the enhancement of cell proliferation in vitro and tumor formation in vivo, as well as the inhibition of cell apoptosis. In conclusion, the present study demonstrated that G3BP1 promoted the progression of colon cancer by activating β-catenin signaling, which provided novel evidence for the role of G3BP1 in colon cancer.

Abstract 5837: Exploring integrated stress response pathway to target MYC-amplified medulloblastoma

Abstract Medulloblastoma (MB) accounts for 20% of diagnosed brain tumors in children. The Group 3 (G3) MB subtype is found to be especially malignant. Current G3 MB treatment regimens provide for 50% 5-year survival rates and are associated with severe side effects, including hearing loss and neurocognitive deficits. G3 MB is characterized by MYC overexpression, which drives elevated protein translation in tumor cells. High expression levels of PERK correlate with poor survival outcome in G3 MB, and knockdown of PERK combined with hypoxic stress induces apoptosis in MB cells. PERK is an eIF2α kinase that responds to ER stress and is one of the key mediators of unfolded protein response. When ER stress is detected, PERK phosphorylates eIF2α to shut down global translation and to initiate integrated stress response. However, there are 3 other eIF2α kinases that work alongside PERK to help cells respond to various stresses. ISRIB is in an integrated stress response inhibitor that blocks P-eIF2α attenuation by eIF2B, thus maintaining high translation levels under stress. Combining ISRIB with stress such as hypoxia induces apoptosis in MB cells. In addition, combination of ISRIB and hypoxia is correlated with increased levels of oxidative stress. Apart from restoring global translation levels, ISRIB can prevent stress granules (SGs) from being formed. High expression of SG proteins such as G3BP1 and YB1 also correlates with poor survival outcome in G3 MB patients. When SG formation is inhibited by knocking down expression of G3BP1 and G3BP2, MB cells undergo higher levels of apoptosis under vincristine induced stress. We show that preventing G3 MB cells from undergoing integrated stress response and inhibiting formation of stress granules induces higher levels of cancer cell death. Overall, combining ISRIB with conventional chemotherapy may enhance the effects of the latter, which is increasingly relevant for patients suffering from G3 MB. Citation Format: Sofya Langman, Poul H. Sorensen. Exploring integrated stress response pathway to target MYC-amplified medulloblastoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5837.

Critical role for G3BP1 in infectious bursal disease virus (IBDV)-induced stress granule formation and viral replication

Stress granules (SGs), complexes for mRNA storage, are formed in host cellular response to stress stimuli and play an important role in innate immune response. GTPase-activating protein (SH3 domain)-binding protein 1 (G3BP1) is a key component of SGs. However, whether IBDV infection induces SG formation in host cells and what role of G3BP1 plays in this process are unclear. We report here that IBDV infection initiated typical stress granule formation and enhanced G3BP1 expression in DF-1 cells. Our data show that knockdown of G3BP1 by RNAi markedly inhibited IBDV-induced SG formation and viral replication in DF-1 cells. Conversely, ectopic expression of G3BP1 enhanced IBDV-induced SG formation and significantly promoted IBDV replication in host cells. Thus, G3BP1 plays a critical role in IBDV-induced SG formation and viral replication, providing an important clue to elucidating how IBDV employs cellular SGs for its own benefits.

Cold atmospheric plasma induces stress granule formation via an eIF2α-dependent pathway.

Cold atmospheric plasma is an ionized gas that shows promise in regenerative medical treatments, yet the mechanisms underlying its effects are still poorly understood. Plasma treatment promotes cell growth or cell death depending on the cell type and exposure parameters. To date, no early cell response to plasma, such as stress granule (SG) formation has been addressed. Cytoplasmic SGs are formed as an immediate cell response to acute stress stimuli by recruitment of over 140 proteins intertwined with cytoplasmic RNAs that leads to transient suspension of protein translation. Encouraged by the plasma effects in regenerative medicine and oncology, the atmospheric pressure plasma jet with argon gas flow is being utilized to treat SH-SY5Y cells with an inducible expression of the stress granule marker G3BP1, to gain an insight into early cell response to plasma and SG formation dynamics. Plasma effectively induces SG formation in the exposed cells in a flow/time-dependent manner, with the SG assembly clearly prompted by plasma-induced oxidative stress. Plasma causes SG formation via eIF2α-signaling, which is repressed with the SG formation inhibitor ISRIB. This insight into the early cell response to plasma treatment may lead to improved therapies in regenerative medicine and cancer treatment.

Elevated expression of G3BP1 associates with YB1 and p-AKT and predicts poor prognosis in nonsmall cell lung cancer patients after surgical resection.

PurposeG3BP1 is an RNA‐binding protein and plays roles in regulating signaling pathway. YB‐1 is a DNA/RNA binding protein encoded by YBX1 gene. Phosphorylated AKT (p‐AKT) acts as a pivotal molecule in PI3K/AKT pathway. YB‐1 drives stress granules (SGs) formation by activating G3BP1 translation under diverse conditions. SGs are involved in many different metabolic and signaling pathways which may include PI3K/AKT/mTOR. So far, there has been no report on the relationship between expression of G3BP1, p‐AKT, and YB1 and clinicopathological features/prognosis in surgically resected nonsmall cell lung cancer (NSCLC) patients.MethodsIn this study, data from TCGA (The Cancer Genome Atlas) were downloaded to investigate the mRNA expression of G3BP1 and YB1 (YBX1) and their correlation in NSCLC. Also, expression of G3BP1, YB1, and p‐AKT proteins was studied using immunohistochemistry in tissue microarrays of NSCLC and in noncancerous lung tissues.ResultsWe found that the mRNA expression of G3BP1 and YB1 was higher in NSCLC tissues (both P < .05), and G3BP1 was positively correlated with YB1 in mRNA level (r = .399, P < .001). Also, expression of G3BP1, YB1, and p‐AKT proteins was higher in NSCLC tissues (all P < .05). And higher expression of G3BP1 and YB1 proteins was seen in patients with clinical stage II and III compared with stage I (both P < .05). Besides, expression of G3BP1 protein had a positive correlation with YB1 and p‐AKT (both P < .05). Moreover, overall survival was shorter in patients with overexpression of G3BP1, YB1, and p‐AKT proteins (all P < .05). Multivariate analysis confirmed that overexpression of G3BP1 protein was an independent poorer prognostic factor for NSCLC patients (P = .039).ConclusionG3BP1 may play a crucial role in activating PI3K/AKT/mTOR pathway. G3BP1 might be served as a novel prognostic biomarker for surgically resected NSCLC patients, which afforded new insights into the study on the mechanism and therapy of NSCLC.

G3BP1 activates the TGF-β/Smad signaling pathway to promote gastric cancer.

BackgroundGTPase-activating protein SH3 domain-binding protein 1 (G3BP1) is involved in various biological functions, including cell growth, metastasis, differentiation, apoptosis, and RNA metabolism. In current study, we aimed to investigate the effect of G3BP1 on gastric cancer (GC).MethodsThe expression of G3BP1 in GC tissues and cell lines was assessed by immunohistochemistry and Western blotting. Correlations of G3BP1 expression with clinicopathological and prognosis of GC patients were evaluated. The functions of G3BP1 in regulating proliferation, migration and invasion of GC cell were investigated using small interfering RNA (siRNA) strategies. Preliminary exploration of its underlying mechanism using Western blotting.ResultsG3BP1 expression was upregulated in GC tissues compared with adjacent tissues, and the higher G3BP1 expression was correlated with poor prognosis. G3BP1 knockdown decreased GC cell proliferation, migration and invasion. Mechanistically, silencing of G3BP1 inhibits the activation of the transforming growth factor (TGF)-β/Smad signaling pathway in GC cells.ConclusionG3BP1 plays an important role in the progression of GC as an oncogene and may become a new therapeutic target.

Genetic defects of chromosome 5q and 7q in myeloid neoplasms

In myeloid neoplasms, deletions of the long arm of chromosome 5 del(5q) and 7 (-7/del(7q) ) are common karyotypic abnormalities. The concurrence of del(5q) and -7/del(7q) accounts for poor prognosis in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Comprehensive analysis of copy number abnormalities and genetic mutations related to del(5q) and -7/del(7q) revealed previously cryptic pathophysiology, leading to frequent hemizygous/homozygous mutations and haploinsufficiency. In addition, detailed somatic mutations on chr5q were detected using whole-exome sequencing. CSNK1A1 and G3BP1 are located within the common deleted regions (CDRs) (5q31.1-5q33.1), and another driver gene DDX41 is present in the more telomeric region (5q35.3). All the genes mentioned above exhibited haploinsufficiency because of deletions, and low expression of G3BP1 and DDX41 correlated with poor survival. The related mutational events outside of chr5q, TP53 mutation is most frequently observed in del(5q) cases. Regarding -7/del(7q), 3 CDRs were located in 7q22, 7q34, and 7q35-36. Somatic mutations of the corresponding genes to each CDR (CUX1: 7q22, LUC7L2: 7q34, EZH2: 7q35-36) were identified, indicating that the loss of function or haploinsufficiency might result in the downstream pathological consequences. These recent findings have remarkably offered insights into genetic and clinical consequences in MDS/AML cases with del(5q) and -7/del(7q).

Foot-and-Mouth Disease Virus Counteracts on Internal Ribosome Entry Site Suppression by G3BP1 and Inhibits G3BP1-Mediated Stress Granule Assembly via Post-Translational Mechanisms.

Foot-and-mouth disease (FMD) is a highly contagious, severe viral illness notifiable to the World Organization for Animal Health. The causative agent, FMD virus (FMDV), replicates rapidly and efficiently inhibits host translation and the innate immune response for it has developed multiple tactics to evade host defenses and takes over gene expression machinery in the host cell. Here, we report a systemic analysis of the proteome and phosphoproteome of FMDV-infected cells. Bioinformatics analysis suggested that FMDV infection shuts off host cap-dependent translation, but leaves intact internal ribosome entry site (IRES)-mediated translation for viral proteins. Interestingly, several FMDV IRES-transacting factors, including G3BP stress granule assembly factor 1 (G3BP1), were dephosphorylated during FMDV infection. Ectopic expression of G3BP1 inhibited FMDV IRES activity, promoted assembly of stress granules, and activated innate immune responses, collectively suppressing FMDV replication. To counteract these host protective responses, FMDV-induced dephosphorylation of G3BP1, compromising its inhibitory effect on viral IRES. In addition, FMDV also proteolytically cleaved G3BP1 by its 3C protease (3Cpro). G3BP1 was cleaved at glutamic acid-284 (E284) by FMDV 3Cpro, and this cleavage completely lost the abilities of G3BP1 to activate innate immunity and to inhibit FMDV replication. Together, these data provide new insights into the post-translational mechanisms by which FMDV limits host stress and antiviral responses and indicate that G3BP1 dephosphorylation and its proteolysis by viral protease are important factors in the failure of host defense against FMDV infection.