GATAD1 gene amplification promotes glioma malignancy by directly regulating CCND1 transcription

LncRNA APTR amplification serves as a potential glioma biomarker and promotes glioma progression via miR-6734-5p/ TCF7/LEF1 axis

Background

Alu-mediated p21 transcriptional regulator (APTR) overexpression is detected in different human cancers; however, few reports have investigated APTR gene amplification conditions. Furthermore, whether APTR amplification is related to glioma malignancy and the underlying mechanism remain unknown.

Methods

APTR amplification and expression levels in 153 glioma samples were analyzed using qPCR. Correlations between APTR and patient prognosis were evaluated using Kaplan-Meier survival and COX regression analyses. Both in vitro and in vivo phenotypic assays were performed to confirm the carcinogenic effects of APTR in glioblastoma (GBM) cells. RNA-sequencing and RNA immunoprecipitation and luciferase reporter assays were performed to confirm APTR as a competing endogenous RNA (ceRNA) and to identify the downstream axis of APTR.

Results

Our results suggest that APTR amplification and overexpression are novel independent diagnostic biomarkers for predicting poor prognosis in patients with gliomas. APTR knockdown significantly repressed the proliferation and invasion of GBM cells, both in vitro and in vivo. APTR was demonstrated to absorb miR-6734-5p and upregulate TCF7 and LEF1 expression. Taken together, these results suggest that APTR promotes the malignant phenotypes of GBM by inducing TCF7 and LEF1 expression.

Conclusion

We identified APTR as a novel prognostic biomarker in patients with gliomas and confirmed that APTR is a ceRNA that promotes glioma progression via the APTR/miR-6734-5p/TCF7/LEF1 axis.

GATAD1 is involved in sphingosylphosphorylcholine-attenuated myocardial ischemia-reperfusion injury by modulating myocardial fatty acid oxidation and glucose oxidation

Modulating the equilibrium between glucose metabolism and fatty acid metabolism represents highly promising novel strategies for therapy of myocardial ischemia/reperfusion (I/R) injury. Sphingosylphosphorylcholine (SPC), an intermediate metabolite of sphingolipids, has shown cardioprotective roles during myocardial infarction by regulating the activities of various transcript factors. Gene microarray revealed that SPC significantly upregulated the expression of GATA zinc finger domain protein 1 (GATAD1), which is a vital transcript factor affecting heart development and various heart diseases. However, it remains unclear whether SPC is involved in the regulation of cardiac fatty acid and glucose metabolism via GATAD1. In this study, we found that myocardium-specific Gatad1 knockout (Gatad1 CKO) significantly increased the myocardial infarct size, impaired cardiac function in I/R mice, and disrupted the protective effect of SPC on the hearts of I/R mice. Immunofluorescence experiment and Western blot evaluation of the nuclear-cytoplasmic fractionation sample showed that GATAD1 acted as a transcription factor and was regulated by SPC. Double fluorescence reporting experiment and quantitative polymerase chain reaction (qPCR) revealed that GATAD1 could inhibit the expression of genes involved in fatty acid oxidation (FAO), i.e., acetyl-coenzyme A acyltransferase 2 (Acaa2) and medium-chain acyl-CoA dehydrogenase (Acadm), and promoted the expression of genes involved in glucose oxidation, i.e., pyruvate dehydrogenase E1 α subunit (Pdha1). Small interfering RNA (SiRNA) or overexpression strategies confirmed the pro-apoptotic roles of Acaa2 and Acadm and anti-apoptotic role of Pdha1 in cardiac myocytes challenged with I/R treatment. In summary, our findings suggest that SPC can be used as a candidate to prevent I/R injury by reshaping fatty acid and glucose metabolism. Transcription factor GATAD1 plays a crucial role in regulating fatty acid oxidation and glucose oxidation homeostasis and is involved in SPC-mediated cardioprotection during I/R of the heart. Our study identifies GATAD1 as a new therapeutic target for clinical treatment of myocardial I/R injury.

CRISPR screen identifies GATAD1 as a synthetic lethal target with CDK4/6 inhibitors in estrogen receptor-positive breast cancer

Estrogen receptor-positive (ER+) breast cancer represents approximately two-thirds of all breast cancers and has a sustained risk of late disease recurrence. Combining cyclin-dependent kinase 4/6 (CDK4/6) inhibitors with anti-estrogen therapies significantly improves ER+ advanced breast cancer clinical outcomes. Despite promising clinical outcomes, intrinsic or acquired resistance to CDK4/6 inhibitors has limited their success. We used CRISPR to screen MCF-7 cells to explore the targets whose inhibition is synthetic lethal with CDK4/6 inhibitors in ER+ breast cancer cells. We found that GATA zinc finger domain containing 1 (GATAD1) is a new synthetic lethal target with CDK4/6 inhibitors in ER+ breast cancer cells. Mechanistically, GATAD1 promotes cell proliferation by transcriptionally inhibiting p21 in ER+ breast cancer cells. GATAD1 depletion decreased the phosphorylation of CDK2/4 and RB transcriptional corepressor 1 (RB1), inducing cell cycle arrest. P21 overexpression abolished the enhanced proliferation induced by GATAD1 overexpression. Our results identify GATAD1 as a therapeutic target in ER+ breast cancer, which is beneficial to provide a novel treatment strategy.

Effect of GATAD1 regulating the SRRM2 gene on recurrence of thyroid tumor and its molecular mechanism

Background

Thyroid blood vessels and nerves are rich, and their anatomical and physiological structures are complex. Surgery often fails to eradicate the tumor, which has a serious negative impact on the surgical outcomes and patient prognosis. Therefore, it is important to accurately predict the recurrence rate of thyroid cancer.

Methods

Based on bioinformatics analysis, the highly expressed transcription factors and differential genes in thyroid carcinoma (THCA) were obtained. Kaplan-Meier survival analysis was used to analyze the clinical effects of GATAD1 as well as SRRM2 on the recurrence of THCA patients. The effect of GATAD1 on SRRM2 expression was explored using cell experiments. Other experiments were conducted to reveal the interaction between SRRM2 and GATAD1 and their functions in THCA progression, such as cell proliferation and cell cycle.

Results

GATAD1 was overexpressed in recurrent THCA tissue compared with that in adjacent normal tissue. GATAD1 and SRRM2 were identified as the key risk factors for THCA recurrence as well as survival. Knockdown of GATAD1 and SRRM2 can inhibit THCA cell proliferation and arrest THCA cells in the G1 phase. Inhibiting GATAD1 decreased SRRM2 expression in THCA cells, whereas overexpressing GATAD1 had the opposite result. SRRM2 knockdown eliminated GATAD1-induced proliferation of THCA cells in vitro, indicating that GATAD1-induced THCA cell proliferation was dependent on increased SRRM2 expression.

Conclusions

We identified GATAD1 as an underlying diagnostic biomarker in THCA recurrence patients. The GATAD1-SRRM2 axis mediates human THCA recurrence progression and is an underlying target for THCA treatment.

Long Noncoding RNA NEAT1 Suppresses Proliferation and Promotes Apoptosis of Glioma Cells Via Downregulating MiR-92b

BACKGROUND

The mechanisms underlying the proliferation and apoptosis of glioma cells remain unelucidated. A recent study has revealed that microRNA-92b (miR-92b) inhibits apoptosis of glioma cells via downregulating DKK3. Notably, long noncoding RNA nuclear-enriched abundant transcript 1 (NEAT1) is predicted to have a possible interaction with miR-92b.

OBJECTIVE

This study aimed to identify whether NEAT1 affects glioma cell proliferation and apoptosis via regulating miR-92b.

METHODS

The expression of NEAT1 was compared between glioma tissues and adjacent tissues as well as between glioma cells and normal astrocytes using quantitative real-time polymerase chain reaction. Glioma cell proliferation was determined by using the 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and glioma cell apoptosis was determined by using the flow cytometry.

RESULTS

The expression of NEAT1 was low in glioma tissues and cells compared to the normal ones. Overexpression of NEAT1 inhibited proliferation and promoted apoptosis of glioma cell lines (U-87 MG and U251). The interaction between NEAT1 and miR-92b was confirmed using RNA immunoprecipitation, RNA pull-down assay, and luciferase reporter assay. Importantly, the tumor suppressor function of overexpressing NEAT1 was achieved by downregulating miR-92b and subsequently upregulating DKK3.

CONCLUSION

Our findings indicated that NEAT1 acts as a tumor suppressor in glioma cells, which provides a novel target in overcoming glioma growth.

GATAD1 gene amplification promotes glioma malignancy by directly regulating CCND1 transcription

Background

The GATAD1 gene overexpression induced by GATAD1 amplification upregulation is detected in different human tumors. To date, the relationship between GATAD1 amplification and glioma oncogenesis and malignancy is still unknown.

Methods

GATAD1 gene amplification and expression were analyzed in 187 gliomas using qPCR and immunostaining. The relation of GATAD1 to patients’ prognoses was assessed via the Kaplan–Meier method. The MTT and orthotopic tumor transplantation assays were used to identify the function of GATAD1 in glioma proliferation. cDNA microarray, ChIP qPCR, EMSA and 3C were used to screen the downstream mechanism of GATAD1 regulating glioma proliferation.

Results

Our results indicated that GATAD1 gene amplification and GATAD1 gene expression are novel independent diagnosis biomarkers to indicate poor outcome of glioma patients. GATAD1 knockdown can remarkably suppress GBM cell proliferation both in vitro and in vivo. GATAD1 could promote CCND1 gene transcription by inducing long range chromatin architectural interaction on the CCND1 promoter. Then GATAD1 sequentially accelerates GBM cell cycle transition and proliferation via regulating CCND1.

Conclusions

We identify GATAD1 as a novel potential diagnosis biomarker and promising prognosis predictor in glioma patients. Functionally, we confirm GATAD1 as an epigenetic chromatin topological regulator that promotes glioma proliferation by targeting CCND1.