GRB10 is a novel factor associated with gastric cancer proliferation and prognosis

GRB10 and its family members GRB7 and GRB14 were important adaptor proteins. They regulated many cellular functions by interacting with various tyrosine kinase receptors and other phosphorus-containing amino acid proteins. More and more studies have shown that the abnormal expression of GRB10 is closely related to the occurrence and development of cancer. In our current research, expression data for 33 cancers from the TCGA database was downloaded for analysis. It was found that GRB10 was up-regulated in cholangiocarcinoma, colon adenocarcinoma, head and neck squamous carcinoma, renal chromophobe, clear renal carcinoma, hepatocellular carcinoma, lung adenocarcinoma, lung squamous carcinoma, gastric adenocarcinoma and thyroid carcinoma. Especially in gastric cancer, the high GRB10 expression was closely associated with poorer overall survival. Further research showed that the knockdown of GRB10 inhibited proliferation and migration ability in gastric cancer. Also, there was a potential binding site for miR-379-5p on the 3'UTR of GRB10. Overexpression of miR-379-5p in gastric cancer cells reduced GRB10-regulated gastric cancer proliferation and migration capacity. In addition, we found that tumor growth was slower in a mice xenograft model with knock down of GRB10 expression. These findings suggested that miR-379-5p suppresses gastric cancer development by downregulating GRB10 expression. Therefore, miR-379-5p and GRB10 were expected to be potential targets for the treatment of gastric cancer.

CircRNA GRB10 is a Novel Biomarker for the Accurate Diagnosis of Lumbar Degenerative Disc Disease

Lumbar degenerative disc disease (LDDD) is frequently misdiagnosed as other spine conditions, and the accurate diagnosis is challenging. This study was conducted to explore the role of circRNA GRB10 in the accurate diagnosis of LDDD. This study included 60 cases of LDDD, 60 cases of patients with sacroiliac joint pain (SJP), 60 cases of lumbar disc herniation (LDH), 60 cases of piriformis syndrome (PS), 60 cases of entrapment neuropathy (EN) and 60 cases of healthy controls (HCs). Plasma was obtained from each patient before and after treatment. Expression of GRB10 was studied with RT-qPCR. The role of plasma GRB10 in the accurate diagnosis of LDDD was analyzed by ROC curve analysis. Compared to HCs, decreased accumulation of GRB10 RNA was only observed in LDDD group, but not in SJP, LDH, PS and EN groups. With plasma expression level of GRB10 measured before treatment as a biomarker, LDDD patients were separated from SJP, LDH, PS, EN and HC groups. After treatment, increased expression levels of GRB10 were only observed in LDDD group, but not in other groups. Therefore, GRB10 was downregulated in LDDD and may serve as a biomarker for the accurate diagnosis of LDDD.

PINCH-1 promotes IGF-1 receptor expression and skin cancer progression through inhibition of the GRB10-NEDD4 complex

Background: Insulin-like growth factor 1 receptor (IGF-1R) expression and signaling play important roles in promotion of skin cancer progression. Identification of signaling pathways that regulate IGF-1R is crucial for understanding the pathogenesis and therapeutic treatment of skin cancer.

Methods: Molecular, cellular and genetic approaches were used to investigate the function of PINCH-1 in regulation of IGF-1R expression and skin cell behavior. Furthermore, conditional PINCH-1 knockout mouse and carcinogen (7, 12-dimethylbenz[a]anthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA))-induced skin cancer model were employed to determine the function of PINCH-1 in regulation of IGF-1R expression and skin carcinogenesis in vivo.

Results: Knockdown of PINCH-1 from HaCaT keratinocytes or A431 squamous carcinoma cells diminished IGF-1R levels, suppressed cell proliferation and increased apoptosis. Re-expression of PINCH-1 in PINCH-1 knockdown cells restored IGF-1R expression, cell proliferation and survival. Furthermore, depletion of NEDD4 effectively reversed PINCH-1 deficiency-induced down-regulation of IGF-1R expression, cell proliferation and survival. Conditional knockout of PINCH-1 from keratin 5 (K5) positive keratinocytes in mice, like depletion of PINCH-1 from keratinocytes in culture, reduced the IGF-1R level. Using a mouse model of DMBA/TPA-induced skin cancer, we show that the levels of both PINCH-1 and IGF-1R were significantly increased in response to treatment with the carcinogens. Genetic ablation of PINCH-1 from the epidermis markedly reduced the IGF-1R expression and cell proliferation despite stimulation with DMBA/TPA, resulting in resistance to chemical carcinogen-induced skin cancer initiation and progression.

Conclusions: Our results reveal a PINCH-1-NEDD4-IGF-1R signaling axis that is critical for promotion of skin tumorigenesis and suggest a new strategy for therapeutic control of skin cancer progression.

GRB10 rs1800504 Polymorphism Is Associated With the Risk of Coronary Heart Disease in Patients With Type 2 Diabetes Mellitus

Diabetic vascular complications are one of the main causes of death and disability. Previous studies have reported that genetic variation is associated with diabetic vascular complications. In this study, we aimed to investigate the association between GRB10 polymorphisms and susceptibility to type 2 diabetes mellitus (T2DM) vascular complications. Eight single nucleotide polymorphisms (SNPs) in the GRB10 gene were genotyped by MassARRAY system and 934 patients with type 2 diabetes mellitus (T2DM) were included for investigation. We found that GRB10 rs1800504 CC+CT genotypes were significantly associated with increased risk of coronary heart disease (CHD) compared with TT genotype (OR = 2.24; 95%CI: 1.36-3.70, p = 0.002). Consistently, levels of cholesterol (CHOL) (CC+CT vs. TT, 4.44 ± 1.25 vs. 4.10 ± 1.00 mmol/L; p = 0.009) and low density lipoprotein cholesterin (LDL-CH) (CC+CT vs. TT, 2.81 ± 1.07 vs. 2.53 ± 0.82 mmol/L; p = 0.01) in T2DM patients with TT genotype were significant lower than those of CC+CT genotypes. We further validated in MIHA cell that the total cholesterol (TC) level in GRB10-Mut was significantly reduced compared with GRB10-WT; p = 0.0005. Likewise, the reversed palmitic acid (PA) induced lipid droplet formation in GRB10-Mut was more effective than in GRB10-WT. These results suggest that rs1800504 of GRB10 variant may be associated with the blood lipids and then may also related to the risk of CHD in patients with T2DM.

Circ_0009910 shuttled by exosomes regulates proliferation, cell cycle and apoptosis of acute myeloid leukemia cells by regulating miR-5195-3p/GRB10 axis

The exosomes are involved in intercellular communication via RNA trafficking in human diseases. Hsa_circ_0009910 (circ_0009910) is a novel leukemia-related circular RNA. However, the mechanism of circ_0009910 in acute myeloid leukemia (AML) cell-to-cell communication remained obscure. Expression of circ_0009910, miRNA (miR)-5195-3p and growth factor receptor-bound protein 10 (GRB10) was detected by quantitative real-time polymerase chain reaction and Western blotting. A stable cell coculture model was established and functional experiment was performed using Cell Counting Kit-8 assay, flow cytometry, and Western blotting. The interaction among circ_0009910, miR-5195-3p and GRB10 was confirmed by dual-luciferase reporter assay and RNA immunoprecipitation. As a result, circ_0009910 was upregulated in AML bone marrows and cells (HL-60 and MOLM-13), even higher in AML cells-derived exosomes. Functionally, blocking circ_0009910 via small interfering RNA (siRNA) suppressed cell proliferation and cell cycle progression, but facilitated apoptosis rate of HL-60 and MOLM-13 cells, accompanied with lower B-cell lymphoma 2 (Bcl-2) level and higher Bcl-2-associated X protein (Bax) level. circ_0009910 shuttled via exosomes negatively regulated miR-5195-3p expression by target binding. Furthermore, circ_0009910 knockdown via exosomes and miR-5195-3p overexpression via mimic resulted in similar results of circ_0009910 siRNA in proliferation, apoptosis and cell cycle progression of AML cells. Meanwhile, the role of circ_0009910 knockdown in AML cells was partially reversed by miR-5195-3p deletion, and restoring GRB10 could abrogate miR-5195-3p effect as well. Notably, GRB10 was a downstream target of miR-5195-3p. circ_0009910-containing exosomes mediated proliferation, apoptosis and cell cycle progression of AML cells partially through miR-5195-3p/GRB10 axis.

miR-222 Suppresses Immature Porcine Sertoli Cell Growth by Targeting the GRB10 Gene Through Inactivating the PI3K/AKT Signaling Pathway

Sertoli cells are central and essential coordinators of spermatogenesis. Accumulating evidence has demonstrated that miRNAs participate in the regulation of Sertoli cell growth. However, the functions and the regulatory mechanisms of miRNAs in Sertoli cells of domestic animals remain largely unknown. Here we report that miR-222 overexpression repressed cell cycle progression and proliferation and promoted the apoptosis of immature porcine Sertoli cells, whereas miR-222 inhibition resulted in the opposite result. miR-222 directly targeted the 3′-UTR of the GRB10 gene and inhibited its mRNA abundance. An siRNA-induced GRB10 knockdown showed similar effects as did miR-222 overexpression on cell proliferation and apoptosis and further attenuated the role of miR-222 inhibition. Furthermore, both miR-222 overexpression and GRB10 inhibition repressed the phosphorylation of PI3K and AKT, the key elements of the PI3K/AKT signaling pathway, whereas GRB10 inhibition offsets the effects of the miR-222 knockdown. Overall, we concluded that miR-222 suppresses immature porcine Sertoli cell growth by targeting the GRB10 gene through inactivation of the PI3K/AKT signaling pathway. This study provides novel insights into the epigenetic regulation of porcine spermatogenesis by determining the fate of Sertoli cells.

GRB10 sustains AR activity by interacting with PP2A in prostate cancer cells

Prostate cancer (PCa) progression is driven by androgen receptor (AR) signaling. Unfortunately, androgen-deprivation therapy and the use of even more potent AR pathway inhibitors (ARPIs) cannot bring about a cure. ARPI resistance (ie, castration-resistant PCa, CRPC) will inevitably develop. Previously, we demonstrated that GRB10 is an AR transcriptionally repressed gene that functionally contributes to CRPC development and ARPI resistance. GRB10 expression is elevated prior to CRPC development in our patient-derived xenograft models and is significantly upregulated in clinical CRPC samples. Here, we analyzed transcriptomic data from GRB10 knockdown in PCa cells and found that AR signaling is downregulated. While the mRNA expression of AR target genes decreased upon GRB10 knockdown, AR expression was not affected at the mRNA or protein level. We further found that phosphorylation of AR serine 81 (S81), which is critical for AR transcriptional activity, is decreased by GRB10 knockdown and increased by its overexpression. Luciferase assay using GRB10-knockdown cells also indicate reduced AR activity. Immunoprecipitation coupled with mass spectrometry revealed an interaction between GRB10 and the PP2A complex, which is a known phosphatase of AR. Further validations and analyses showed that GRB10 binds to the PP2Ac catalytic subunit with its PH domain. Mechanistically, GRB10 knockdown increased PP2Ac protein stability, which in turn decreased AR S81 phosphorylation and reduced AR activity. Our findings indicate a reciprocal feedback between GRB10 and AR signaling, implying the importance of GRB10 in PCa progression.

Contribution of GRB10 to the prenatal phenotype in Silver-Russell syndrome? Lessons from 7p12 copy number variations

The growth factor binding protein 10 (GRB10) has been suggested as a candidate gene for Silver-Russell syndrome because of its localization in 7p12, its imprinting status, data from mice models and its putative role in growth. Based on a new patient with normal growth carrying a GRB10 deletion affecting the paternal allele and data from the literature, we conclude that the heterogeneous clinical findings in patients with copy number variations (CNVs) of GRB10 gene depend on the size and the gene content of the CNV. However, evidence from mouse and human cases indicate a growth suppressing role of GRB10 in prenatal development. As a result, an increase of active maternal GRB10 copies, e.g. by maternal uniparental disomy of chromosome 7 or duplications of the region results in intrauterine growth retardation. In contrast, a defective GRB10 copy might result in prenatal overgrowth, whereas the paternal GRB10 allele is not required for proper prenatal growth.

Proproliferative function of adaptor protein GRB10 in prostate carcinoma

Growth factor receptor-binding protein 10 (GRB10) is a well-known adaptor protein and a recently identified substrate of the mammalian target of rapamycin (mTOR). Depletion of GRB10 increases insulin sensitivity and overexpression suppresses PI3K/Akt signaling. Because the major reason for the limited efficacy of PI3K/Akt-targeted therapies in prostate cancer (PCa) is loss of mTOR-regulated feedback suppression, it is therefore important to assess the functional importance and regulation of GRB10 under these conditions. On the basis of these background observations, we explored the status and functional impact of GRB10 in PCa and found maximum expression in phosphatase and tensin homolog (PTEN)-deficient PCa. In human PCa samples, GRB10 inversely correlated with PTEN and positively correlated with pAKT levels. Knockdown of GRB10 in nontumorigenic PTEN null mouse embryonic fibroblasts and tumorigenic PCa cell lines reduced Akt phosphorylation and selectively activated a panel of receptor tyrosine kinases. Similarly, overexpression of GRB10 in PTEN wild-type PCa cell lines accelerated tumorigenesis and induced Akt phosphorylation. In PTEN wild-type PCa, GRB10 overexpression promoted mediated PTEN interaction and degradation. PI3K (but not mTOR) inhibitors reduced GRB10 expression, suggesting primarily PI3K-driven regulation of GRB10. In summary, our results suggest that GRB10 acts as a major downstream effector of PI3K and has tumor-promoting effects in prostate cancer.-Khan, M. I., Al Johani, A., Hamid, A., Ateeq, B., Manzar, N., Adhami, V. M., Lall, R. K., Rath, S., Sechi, M., Siddiqui, I. A., Choudhry, H., Zamzami, M. A., Havighurst, T. C., Huang, W., Ntambi, J. M., Mukhtar, H. Proproliferatve function of adaptor protein GRB10 in prostate carcinoma.

Maternal 5mCpG Imprints at the PARD6G-AS1 and GCSAML Differentially Methylated Regions Are Decoupled From Parent-of-Origin Expression Effects in Multiple Human Tissues

A hallmark of imprinted genes in mammals is the occurrence of parent-of-origin-dependent asymmetry of DNA cytosine methylation (5^mC) of alleles at CpG islands (CGIs) in their promoter regions. This 5^mCpG asymmetry between the parental alleles creates allele-specific imprinted differentially methylated regions (iDMRs). iDMRs are often coupled to the transcriptional repression of the methylated allele and the activation of the unmethylated allele in a tissue-specific, developmental-stage-specific and/or isoform-specific fashion. iDMRs function as regulatory platforms, built through the recruitment of chemical modifications to histones to achieve differential, parent-of-origin-dependent chromatin segmentation states. Here, we used a comparative computational data mining approach to identify 125 novel constitutive candidate iDMRs that integrate the maximal number of allele-specific methylation region records overlapping CGIs in human methylomes. Twenty-nine candidate iDMRs display gametic 5^mCpG asymmetry, and another 96 are candidate secondary iDMRs. We established the maternal origin of the 5^mCpG imprints of one gametic (PARD6G-AS1) and one secondary (GCSAML) iDMRs. We also found a constitutively hemimethylated, nonimprinted domain at the PWWP2AP1 promoter CGI with oocyte-derived methylation asymmetry. Given that the 5^mCpG level at the iDMRs is not a sufficient criterion to predict active or silent locus states and that iDMRs can regulate genes from a distance of more than 1 Mb, we used RNA-Seq experiments from the Genotype-Tissue Expression project and public archives to assess the transcriptional expression profiles of SNPs across 4.6 Mb spans around the novel maternal iDMRs. We showed that PARD6G-AS1 and GCSAML are expressed biallelically in multiple tissues. We found evidence of tissue-specific monoallelic expression of ZNF124 and OR2L13, located 363 kb upstream and 419 kb downstream, respectively, of the GCSAML iDMR. We hypothesize that the GCSAML iDMR regulates the tissue-specific, monoallelic expression of ZNF124 but not of OR2L13. We annotated the non-coding epigenomic marks in the two maternal iDMRs using data from the Roadmap Epigenomics project and showed that the PARD6G-AS1 and GCSAML iDMRs achieve contrasting activation and repression chromatin segmentations. Lastly, we found that the maternal 5^mCpG imprints are perturbed in several hematopoietic cancers. We conclude that the maternal 5^mCpG imprints at PARD6G-AS1 and GCSAML iDMRs are decoupled from parent-of-origin transcriptional expression effects in multiple tissues.

The TORC1-activated Proteins, p70S6K and GRB10, Regulate IL-4 Signaling and M2 Macrophage Polarization by Modulating Phosphorylation of Insulin Receptor Substrate-2

Lung M2 macrophages are regulators of airway inflammation, associated with poor lung function in allergic asthma. Previously, we demonstrated that IL-4-induced M2 gene expression correlated with tyrosine phosphorylation of the insulin receptor substrate-2 (IRS-2) in macrophages. We hypothesized that negative regulation of IRS-2 activity after IL-4 stimulation is dependent upon serine phosphorylation of IRS-2. Herein, we describe an inverse relationship between tyrosine phosphorylation (Tyr(P)) and serine phosphorylation (Ser(P)) of IRS-2 after IL-4 stimulation. Inhibiting serine phosphatase activity increased Ser(P)-IRS-2 and decreased Tyr(P)-IRS-2 leading to reduced M2 gene expression (CD200R, CCL22, MMP12, and TGM2). We found that inhibition of p70S6K, downstream of TORC1, resulted in diminished Ser(P)-IRS-2 and prolonged Tyr(P)-IRS-2 as well. Inhibition of p70S6K increased expression of CD200R and CCL22 indicating that p70S6K negatively regulates some, but not all, human M2 genes. Knocking down GRB10, another negative regulatory protein downstream of TORC1, enhanced both Tyr(P)-IRS-2 and increased expression of all four M2 genes. Furthermore, GRB10 associated with IRS-2, NEDD4.2 (an E3-ubiquitin ligase), IL-4Rα, and γC after IL-4 stimulation. Both IL-4Rα and γC were ubiquitinated after 30 min of IL-4 treatment, suggesting that GRB10 may regulate degradation of the IL-4 receptor-signaling complex through interactions with NEDD4.2. Taken together, these data highlight two novel regulatory proteins that could be therapeutically manipulated to limit IL-4-induced IRS-2 signaling and polarization of M2 macrophages in allergic inflammation.

FGFR3 gene mutation plus GRB10 gene duplication in a patient with achondroplasia plus growth delay with prenatal onset

Background

Achondroplasia is a well-defined and common bone dysplasia. Genotype- and phenotype-level correlations have been found between the clinical symptoms of achondroplasia and achondroplasia-specific FGFR3 mutations.

Result

A 2-year-old boy with clinical features consistent with achondroplasia and Silver-Russell syndrome-like symptoms was found to carry a mutation in the fibroblast growth factor receptor-3 (FGFR3) gene at c.1138G > A (p.Gly380Arg) and a de novo 574 kb duplication at chromosome 7p12.1 that involved the entire growth-factor receptor bound protein 10 (GRB10) gene. Using quantitative real-time PCR analysis, GRB10 was over-expressed, and, using enzyme-linked immunosorbent assays for IGF1 and IGF-binding protein-3 (IGFBP3), we found that IGF1 and IGFBP3 were low-expressed in this patient.

Conclusions

We demonstrate that a combination of uncommon, rare and exceptional molecular defects related to the molecular bases of particular birth defects can be analyzed and diagnosed to potentially explain the observed variability in the combination of molecular defects.

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-016-0465-4) contains supplementary material, which is available to authorized users.

Carrageenan Inhibits Insulin Signaling through GRB10-mediated Decrease in Tyr(P)-IRS1 and through Inflammation-induced Increase in Ser(P)307-IRS1

Inflammation induced by exposure to the common food additive carrageenan leads to insulin resistance by increase in Ser(P)(307)-insulin receptor substrate 1 (IRS1) and subsequent decline in the insulin-stimulated increase in Ser(P)(473)-AKT. Inhibition of carrageenan-induced inflammation reversed the increase in Ser(P)(307)-IRS1 but did not completely reverse the carrageenan-induced decline in Ser(P)(473)-AKT. To identify the additional mechanism responsible for the decrease in Ser(P)(473)-AKT, studies were performed in human HepG2 cells and in C57BL/6J mice. Following carrageenan, expression of GRB10 (growth factor receptor-bound 10 protein), an adaptor protein that binds to the insulin receptor and inhibits insulin signaling, increased significantly. GRB10 silencing blocked the carrageenan-induced reduction of the insulin-stimulated increase in Tyr(P)-IRS1 and partially reversed the decline in Ser(P)(473)-AKT. The combination of GRB10 silencing with BCL10 silencing and the reactive oxygen species inhibitor Tempol completely reversed the decline in Ser(P)(473)-AKT. After carrageenan, GRB10 promoter activity was enhanced because of activation by GATA2. A direct correlation between Ser(P)(473)-AKT and Ser(P)(401)-GATA2 was evident, and inhibition of AKT phosphorylation by the PI3K inhibitor LY294002 blocked Ser(401)-GATA2 phosphorylation and the increase in GRB10 expression. Studies indicated that carrageenan inhibited insulin signaling by two mechanisms: through the inflammation-mediated increase in Ser(P)(307)-IRS1, a negative regulator of insulin signaling, and through a transcriptional mechanism leading to increase in GRB10 expression and GRB10-inhibition of Tyr(P)-IRS1, a positive regulator of insulin signaling. These mechanisms converge to inhibit the insulin-induced increase in Ser(P)(473)-AKT. They provide internal feedback, mediated by Ser(P)(473)-AKT, Ser(P)(401)-GATA2, and nuclear GATA2, which links the opposing effects of serine and tyrosine phosphorylations of IRS1 and can modulate insulin responsiveness.

Association of the intronic polymorphism rs12540874 A>G of the GRB10 gene with high birth weight

BACKGROUND

High birth weight (HBW) is considered a key predictor of the development of chronic diseases, such as Type 2 Diabetes (T2D). Foetal growth depends on many factors, among which placental function is critical. Some genes with expression in the placenta, such as GRB10, are known to be involved in the regulation of insulin receptor pathways and the size of mouse littermates.

AIM

To evaluate whether the intronic polymorphism rs12540874 A>G of the GRB10 gene is associated with HBW in term newborns.

STUDY DESIGN

A total of 51 healthy term newborns were enrolled in a nested case-control study. The case group was defined by the presence of HBW (n=17) and the control group by newborns with normal birth weight (NBW n=34). Maternal and foetal factors influencing HBW were considered as exclusion criteria. The polymorphism was determined through real-time PCR using TaqMan technology. Categorical variables were evaluated with descriptive statistics, and multivariate logistic regression analysis was used to evaluate the association between polymorphism and HBW.

RESULTS

The newborns in the case group had a longer gestation period (39. 7 ± 1.0 and 38.8 ± 1.8 weeks) and higher insulin levels at birth (9.5 ± 4.0 and 5.7 ± 3.4 μU/mL) than the newborns in the control group. The multivariate regression analysis, adjusted for weeks of gestation, showed a significant association between the SNP rs12540874 A>G of the GRB10 gene with HBW (OR 4.9; CI95% 1.10-22.10 p=0.02).

CONCLUSIONS

Our results suggest that the SNP rs12540874 A>G, an intronic SNP of the gene GRB10, is associated with HBW.