Syndrome Critical Region Gene Research Articles

Rcn1, the fission yeast homolog of human DSCR1, regulates arsenite tolerance independently from calcineurin.

Calcineurin (CN) is a conserved Ca2+/calmodulin-dependent phosphoprotein phosphatase that plays a key role in Ca2+ signaling. Regulator of calcineurin 1 (RCAN1), also known as Down syndrome critical region gene 1 (DSCR1), interacts with calcineurin and inhibits calcineurin-dependent signaling in various organisms. Ppb1, the fission yeast calcineurin regulates Cl--homeostasis, and Ppb1 deletion induces MgCl2 hypersensitivity. Here, we characterize the conserved and novel roles of the fission yeast RCAN1 homolog rcn1+. Consistent with its role as an endogenous calcineurin inhibitor, Rcn1 overproduction reproduced the calcineurin-null phenotypes, including MgCl2 hypersensitivity and inhibition of calcineurin signaling upon extracellular Ca2+ stimuli as evaluated by the nuclear translocation and transcriptional activation of the calcineurin substrate Prz1. Notably, overexpression of rcn1+ causes hypersensitivity to arsenite, whereas calcineurin deletion induces arsenite tolerance, showing a phenotypic discrepancy between Rcn1 overexpression and calcineurin deletion. Importantly, although Rcn1 deletion induces modest sensitivities to arsenite and MgCl2 in wild-type cells, the arsenite tolerance, but not MgCl2 sensitivity, associated with Ppb1 deletion was markedly suppressed by Rcn1 deletion. Collectively, our findings reveal a previously unrecognized functional collaboration between Rcn1 and calcineurin, wherein Rcn1 not only negatively regulates calcineurin in the Cl- homeostasis, but also Rcn1 mediates calcineurin signaling to modulate arsenite cytotoxicity.

The role of long noncoding RNA DGCR5 in cancers: Focus on molecular targets.

Long noncoding RNAs (lncRNAs) are major components of cellular transcripts that are emerging as important players in various biological pathways. Due to their specific expression and functional diversity in a variety of cancers, lncRNAs have promising applications in cancer diagnosis, prognosis, and therapy. Studies have shown that lncRNA DiGeorge syndrome critical region gene 5 (DGCR5) with high specificity and accuracy has the potential to become biomarkers in cancers. LncRNA DGCR5 can be noninvasively extracted from body fluids, tissues, and cells, and can be used as independent or auxiliary biomarkers to improve the accuracy of diagnosis or prognosis. Now, the underlying mechanisms of lncRNAs such as DGCR5 were explored as therapeutic targets, which have been investigated in clinical trials of several cancers. The DGCR5 lacks an appropriate animal model, which is necessary to gain greater knowledge of their functions. While some studies on the uses of DGCR5 have been carried out, the small sample size makes them unreliable. In this review, we presented a compilation of recent publications addressing the potential of lncRNA DGCR5 that could be considered as biomarkers or therapeutic targets, with the hopes of providing promised implications for future cancer therapy.

DiGeorge syndrome critical region gene 2 (DGCR2), a schizophrenia risk gene, regulates dendritic spine development through cell adhesion

BackgroundDendritic spines are the sites of excitatory synapses on pyramidal neurons, and their development is crucial for neural circuits and brain functions. The spine shape, size, or number alterations are associated with neurological disorders, including schizophrenia. DiGeorge syndrome critical region gene 2 (DGCR2) is one of the deleted genes within the 22q11.2 deletion syndrome (22q11DS), which is a high risk for developing schizophrenia. DGCR2 expression was reduced in schizophrenics. However, the pathophysiological mechanism of DGCR2 in schizophrenia or 22q11DS is still unclear.ResultsHere, we report that DGCR2 expression was increased during the neurodevelopmental period and enriched in the postsynaptic densities (PSDs). DGCR2-deficient hippocampal neurons formed fewer spines. In agreement, glutamatergic transmission and synaptic plasticity were decreased in the hippocampus of DGCR2-deficient mice. Further molecular studies showed that the extracellular domain (ECD) of DGCR2 is responsible for its transcellular interaction with cell adhesion molecule Neurexin1 (NRXN1) and spine development. Consequently, abnormal behaviors, like anxiety, were observed in DGCR2-deficient mice.ConclusionsThese observations indicate that DGCR2 is a novel cell adhesion molecule required for spine development and synaptic plasticity, and its deficiency induces abnormal behaviors in mice. This study provides a potential pathophysiological mechanism of DGCR2 in 22q11DS and related mental disorders.

Activation of the HNRNPA2B1/miR-93-5p/FRMD6 axis facilitates prostate cancer progression in an m6A-dependent manner.

It is becoming increasingly clear that N6-methyladenosine (m6A) plays a key role in post-transcriptional modification of eukaryotic RNAs in cancer. The regulatory mechanism of m6A modifications in prostate cancer is still not completely elucidated. Heterogeneous nuclear ribonucleoprotein A2/B1 (HNRNPA2B1), an m6A reader, has been revealed to function as an oncogenic RNA-binding protein. However, its contribution to prostate cancer progression remains poorly understood. Here, we found that HNRNPA2B1 was highly overexpressed and correlated with a poor prognosis in prostate cancer. In vitro and in vivo functional experiments demonstrated that HNRNPA2B1 knockout impaired proliferation and metastasis of prostate cancer. Mechanistic studies indicated that HNRNPA2B1 interacted with primary miRNA-93 and promoted its processing by recruiting DiGeorge syndrome critical region gene 8 (DGCR8), a key subunit of the Microprocessor complex, in an METTL3-dependent mechanism, while HNRNPA2B1 knockout significantly restored miR-93-5p levels. HNRNPA2B1/miR-93-5p downregulated FERM domain-containing protein 6 (FRMD6), a cancer suppressor, and enhanced proliferation and metastasis in prostate cancer. In conclusion, our findings identified a novel oncogenic axis, HNRNPA2B1/miR-93-5p/FRMD6, that stimulates prostate cancer progression via an m6A-dependent manner.

The developmentally timed decay of an essential microRNA family is seed-sequence dependent.

SUMMARYMicroRNA (miRNA) abundance is tightly controlled by regulation of biogenesis and decay. Here, we show that the mir-35 miRNA family undergoes selective decay at the transition from embryonic to larval development in C. elegans. The seed sequence of the miRNA is necessary and largely sufficient for this regulation. Sequences outside the seed (3′ end) regulate mir-35 abundance in the embryo but are not necessary for sharp decay at the transition to larval development. Enzymatic modifications of the miRNA 3′ end are neither prevalent nor correlated with changes in decay, suggesting that miRNA 3′ end display is not a core feature of this mechanism and further supporting a seed-driven decay model. Our findings demonstrate that seed-sequence-specific decay can selectively and coherently regulate all redundant members of a miRNA seed family, a class of mechanism that has great biological and therapeutic potential for dynamic regulation of a miRNA family’s target repertoire.

METTL3-mediated m6A modification promotes processing and maturation of pri-miRNA-19a to facilitate nasopharyngeal carcinoma cell proliferation and invasion.

The interplay between N6-methyladenosine (m6A) modification and microRNAs (miRs) participates in cancer progression. This study is conducted to explore the role of miR-19a-3p in nasopharyngeal carcinoma (NPC) cell proliferation and invasion. Reverse transcription quantitative polymerase chain reaction and Western blot showed that miR-19a-3p was upregulated in NPC tissues and cells and related to poor prognosis, methyltransferase-like 3 (METTL3) was highly expressed, whereas BMP and activin membrane-bound inhibitor (BAMBI) was weakly expressed in NPC tissues and cells. miR-19a-3p downregulation inhibited cell proliferation and invasion, whereas miR-19a-3p overexpression played the opposite role. m6A quantification and m6A RNA immunoprecipitation assays showed that METTL3-mediated m6A modification promoted the processing and maturation of pri-miR-19a via DiGeorge syndrome critical region gene 8 (DGCR8). Dual-luciferase assay showed that BAMBI was a target of miR-19a-3p. The rescue experiments showed that BAMBI downregulation reversed the role of miR-19a-3p inhibition in NPC cells. A xenograft tumor model showed that METTL3 downregulation inhibited tumor growth via the miR-19a-3p/BAMBI in vivo. Overall, our findings elicited that METTL3-mediated m6A modification facilitated the processing and maturation of pri-miR-19a via DGCR8 to upregulate miR-19a-3p, and miR-19a-3p inhibited BAMBI expression to promote NPC cell proliferation and invasion, thus driving NPC progression.

Upregulation of DGCR8, a Candidate Predisposing to Schizophrenia in Han Chinese, Contributes to Phenotypic Deficits and Neuronal Migration Delay.

DiGeorge Syndrome Critical Region Gene 8 (DGCR8) is a key component of the microprocessor complex governing the maturation of most microRNAs, some of which participate in schizophrenia and neural development. Previous studies have found that the 22q11.2 locus, containing DGCR8, confers a risk of schizophrenia. However, the role of DGCR8 in schizophrenia and the early stage of neural development has remained unknown. In the present study, we try to identify the role of DGCR8 in schizophrenia from human samples and animal models. We found that the G allele and GG genotype of rs3757 in DGCR8 conferred a higher risk of schizophrenia, which likely resulted from higher expression of DGCR8 according to our test of dual-luciferase reporter system. Employed overexpression model in utero and adult mice, we also revealed that the aberrant increase of Dgcr8 delayed neuronal migration during embryological development and consequently triggered abnormal behaviors in adult mice. Together, these results demonstrate that DGCR8 may play a role in the etiology of schizophrenia through regulating neural development.

Mechanism of METTL3-mediated m6A modification in depression-induced cognitive deficits.

Depressive disorder (DD) is associated with N6-methyladenosine (m6A) hypermethylation. This study sought to explore the molecular mechanism of Methyltransferase-like 3 (METTL3) in cognitive deficits of chronic unpredictable mild stress (CUMS)-treated rats and provide novel targets for DD treatment. A DD rat model was established via CUMS treatment. Cognitive deficits were assessed via body weighing and behavioral tests. METTL3, microRNA (miR)-221-3p, pri-miR-221, GRB2-associated binding protein 1 (Gab1) expressions in hippocampal tissues were detected via RT-qPCR and Western blotting. m6A, DiGeorge syndrome critical region gene 8 (DGCR8)-bound pri-miR-221 and pri-miR-221 m6A levels were measured. The binding relationship between miR-221-3p and Gab1 was testified by dual-luciferase and RNA pull-down assays. Rescue experiments were designed to confirm the role of miR-221-3p and Gab1. METTL3 was highly expressed in CUMS rats, and silencing METTL3 attenuated cognitive deficits of CUMS rats. METTL3-mediated m6A modification facilitated processing and maturation of pri-miR-221 via DGCR8 to upregulate miR-221-3p. miR-221-3p targeted Gab1. miR-221-3p overexpression or Gab1 downregulation reversed the role of silencing METTL3 in CUMS rats. Overall, METTL3-mediated m6A modification facilitated processing and maturation of pri-miR-221 to upregulate miR-221-3p and then inhibit Gab1, thereby aggravating cognitive deficits of CUMS rats.

DGCR5 is Activated by PAX5 and Promotes Pancreatic Cancer via Targeting miR-3163/TOP2A and Activating Wnt/β-Catenin Pathway

Background: DiGeorge syndrome critical region gene 5 (DGCR5) has been shown to be associated with cancer development. However, the biological role and molecular mechanism of DGCR5 in pancreatic cancer (PC) remains largely unknown. Methods: qRT-PCR and fluorescence in situ hybridization was performed to investigate the correlation between DGCR5 expression and prognosis and clinicopathologic characteristics of PC patients. The effects of DGCR5 on PC were studied by gain & loss-of-function experiments in vitro and in vivo. RNA sequencing, bioinformatics analyses, dual-luciferase assays, chromatin immunoprecipitation assay and rescue experiments provided insights into the underlying competing endogenous RNA (ceRNA) mechanism network of DGCR5 in promoting PC progression. Results: DGCR5 was highly expressed in PC tissues compared with adjacent normal tissues and its high expression was associated with poor prognosis in PC patients. Furthermore, DGCR5 depletion inhibited the proliferation, migration and invasion by increasing apoptosis and inducing G0/G1 cell cycle arrest in vitro. Moreover, xenograft assay validated that DGCR5 promotes PC tumor growth in vivo. Mechanistically, DGCR5 was found to act as a ceRNA by sponging miR-3163 to regulate TOP2A and inhibit Wnt/β-catenin pathway. In addition, we found that DGCR5 downregulation could enhance the sensitivity of PC cells to gemcitabine, and ChIP assay showed that the transcription factor PAX5 could bind to the DGCR5 promoter and increase its transcription. Conclusions: Our study demonstrates that DGCR5 is activated by PAX5 and promotes PC progression by sponging miR-3163 to regulate TOP2A and activating wnt/β-catenin pathway, suggesting that DGCR5 may be a potential diagnostic and therapeutic target for PC.

CCR1 enhances SUMOylation of DGCR8 by up-regulating ERK phosphorylation to promote spinal nerve ligation-induced neuropathic pain.

Neuropathic pain is a somatosensory nervous system dysfunction that remains a threatening health problem globally. Recent studies have highlighted the involvement of C-C motif chemokine receptor 1 (CCR1) in neuropathic pain. Herein, the current study set out to explore the modulatory role of CCR1 in spinal nerve ligation (SNL)-induced neuropathic pain and its underlying molecular mechanism. First, it was found that CCR1 was highly expressed in spinal cord tissues and microglial cells of SNL rats. On the other hand, CCR1 knockdown attenuated nerve pain in SNL rats and repressed microglial cell activation in SNL rats and also in the LPS-induced microglial cell model of nerve injury, as evidenced by elevated microglial cell markers OX-42 and IL-1β, IL-6 and TNF-α. Mechanistically, CCR1 enhanced small ubiquitin-like modifier 1 (SUMO1) modification of DiGeorge syndrome critical region gene 8 (DGCR8) in LPS-treated microglial cells by phosphorylating ERK. Moreover, CCR1 silencing brought about elevations in mechanical withdrawal threshold and thermal withdrawal latency. To conclude, our findings indicated that CCR1 enhanced the modification of DGCR8 by SUMO1 through phosphorylation of ERK, thereby promoting the activation and inflammatory response of spinal cord microglial cells and increasing the sensitivity of SNL rats to pain. Thus, this study offers a promising therapeutic target for the management of neuropathic pain.

LncRNA DGCR5 Isoform-1 Silencing Suppresses the Malignant Phenotype of Clear Cell Renal Cell Carcinoma via miR-211-5p/Snail Signal Axis.

Long non-coding RNAs (lncRNAs) play important roles during the initiation and progression of cancer. We identified DiGeorge Syndrome Critical Region Gene 5 (DGCR5) as a clear cell renal cell carcinoma (ccRCC) cancer- and lineage-specific lncRNA. Agarose gel electrophoresis analysis and sanger sequencing verified two main isoforms of DGCR5 in ccRCC patient tissues and cell lines. Quantitative polymerase chain reaction further demonstrated that the expression level of DGCR5 major isoform (isoform-1) was higher in ccRCC tissues than that in papillary/chromophobe RCC and other multiple solid malignant tumors. We investigate the biological functions of DGCR5 isoform-1 in ccRCC and show that DGCR5 isoform-1 exerts a tumor-promoting effect in ccRCC. DGCR5 isoform-1 is localized in cytoplasm and shares the same binding sequence to the tumor-suppressive miR-211-5p with the epithelial-to-mesenchymal transition key component SNAI. Furthermore, cellular and molecular experiments demonstrate that DGCR5 isoform-1 could sequester miR-211-5p, leading to the elevation of Snail protein and downregulation of its downstream targets and further promoting ccRCC cell proliferation and migration. Thus, our study indicates that DGCR5 isoform-1 could contribute to ccRCC progression by sponging miR-211-5p through regulating the expression of Snail protein and could serve as a reliable diagnostic biomarker in ccRCC.

Long noncoding RNA DGCR5 involves in tumorigenesis of esophageal squamous cell carcinoma via SRSF1-mediated alternative splicing of Mcl-1

Long noncoding RNAs (lncRNAs) emerge as essential roles in the regulation of alternative splicing (AS) in various malignancies. Serine- and arginine-rich splicing factor 1 (SRSF1)-mediated AS events are the most important molecular hallmarks in cancer. Nevertheless, the biological mechanism underlying tumorigenesis of lncRNAs correlated with SRSF1 in esophageal squamous cell carcinoma (ESCC) remains elusive. In this study, we found that lncRNA DiGeorge syndrome critical region gene 5 (DGCR5) was upregulated in ESCC clinical samples, which associated with poor prognosis. Through RNA interference and overexpression approaches, we confirmed that DGCR5 contributed to promote ESCC cell proliferation, migration, and invasion while inhibited apoptosis in vitro. Mechanistically, DGCR5 could directly bind with SRSF1 to increase its stability and thus stimulate alternative splicing events. Furthermore, we clarified that SRSF1 regulated the aberrant splicing of myeloid cell leukemia-1 (Mcl-1) and initiated a significant Mcl-1L (antiapoptotic) isoform switch, which contributed to the expression of the full length of Mcl-1. Moreover, the cell-derived xenograft (CDX) model was validated that DGCR5 could facilitate the tumorigenesis of ESCC in vivo. Collectively, our findings identified that the key biological role of lncRNA DGCR5 in alternative splicing regulation and emphasized DGCR5 as a potential biomarker and therapeutic target for ESCC.

Silencing lncRNA-DGCR5 increased trophoblast cell migration, invasion and tube formation, and inhibited cell apoptosis via targeting miR-454-3p/GADD45A axis.

Long noncoding RNA (lncRNA)-DGCR5 has been recognized as a potential tumor progression regulator, while its expression and specific functions in preeclampsia (PE) development remain unveiled. The expressions of miR-454-3p, lncRNA-DiGeorge syndrome critical region gene 5 (DGCR5) and growth arrest and DNA damage protein-inducible 45A (GADD45A) in placental tissues from PE patients or HTR-8/SVneo cells were assessed by Western blot or qRT-PCR. Dual-luciferase reporter assay determined the binding relations between miR-454-3p and GADD45A and between miR-454-3p and lncRNA-DGCR5. The viability, apoptosis, migration, invasiveness and tube formation of HTR-8/SVneo cell were evaluated using cell counting kit (CCK)-8, Annexin-V/Propidium iodide staining, wound healing, transwell and tube formation assays, respectively. miR-454-3p was low-expressed in PE tissue, and upregulation of miR-454-3p increased viability and promoted migration, invasion and tube formation in HTR-8/SVneo cells while inhibiting apoptosis. Then, miR-454-3p was found to directly target GADD45A which was high-expressed in PE tissues. Overexpressing GADD45A decreased the viability and inhibited the migration, invasion and tube formation of HTR-8/SVneo cells while enhancing apoptosis, and it neutralized the effect of miR-454-3p upregulation. In turn, miR-454-3p upregulation reversed the effect of GADD45A overexpression. Meanwhile, miR-454-3p could also target lncRNA-DGCR5. Silencing lncRNA-DGCR5 increased miR-454-3p expression and cell viability and promoted migration, invasion and tube formation in HTR-8/SVneo cells while inhibiting apoptosis, and it counteracted the effect of miR-454-3p downregulation. As usual, miR-454-3p downregulation reversed the effect of lncRNA-DGCR5 silencing. To conclude, silencing lncRNA-DGCR5 increased viability, promoted migration, invasion and tube formation, and inhibited apoptosis in HTR-8/SVneo cells by rescuing the inhibition of GADD45A expression caused by miR-454-3p.

Long Non-Coding RNA CRNDE Is Involved in Resistance to EGFR Tyrosine Kinase Inhibitor in EGFR-Mutant Lung Cancer via eIF4A3/MUC1/EGFR Signaling.

(1) Background: Acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) is an intractable problem for many clinical oncologists. The mechanisms of resistance to EGFR-TKIs are complex. Long non-coding RNAs (lncRNAs) may play an important role in cancer development and metastasis. However, the biological process between lncRNAs and drug resistance to EGFR-mutated lung cancer remains largely unknown. (2) Methods: Osimertinib- and afatinib-resistant EGFR-mutated lung cancer cells were established using a stepwise method. A microarray analysis of non-coding and coding RNAs was performed using parental and resistant EGFR-mutant non-small cell lung cancer (NSCLC) cells and evaluated by bioinformatics analysis through medical-industrial collaboration. (3) Results: Colorectal neoplasia differentially expressed (CRNDE) and DiGeorge syndrome critical region gene 5 (DGCR5) lncRNAs were highly expressed in EGFR-TKI-resistant cells by microarray analysis. RNA-protein binding analysis revealed eukaryotic translation initiation factor 4A3 (eIF4A3) bound in an overlapping manner to CRNDE and DGCR5. The CRNDE downregulates the expression of eIF4A3, mucin 1 (MUC1), and phospho-EGFR. Inhibition of CRNDE activated the eIF4A3/MUC1/EGFR signaling pathway and apoptotic activity, and restored sensitivity to EGFR-TKIs. (4) Conclusions: The results showed that CRNDE is associated with the development of resistance to EGFR-TKIs. CRNDE may be a novel therapeutic target to conquer EGFR-mutant NSCLC.

DGCR8-dependent efficient pri-miRNA processing of human pri-miR-9-2

Microprocessor complex, including DiGeorge syndrome critical region gene 8 (DGCR8) and DROSHA, recognizes and cleaves primary transcripts of microRNAs (pri-miRNAs) in the maturation of canonical miRNAs. The study of DGCR8 haploinsufficiency reveals that the efficiency of this activity varies for different miRNA species. It is thought that this variation might be associated with the risk of schizophrenia with 22q11 deletion syndrome caused by disruption of the DGCR8 gene. However, the underlying mechanism for varying action of DGCR8 with each miRNA remains largely unknown. Here, we used in vivo monitoring to measure the efficiency of DGCR8-dependent microprocessor activity in cultured cells. We confirmed that this system recapitulates the microprocessor activity of endogenous pri-miRNA with expression of a ratiometric fluorescence reporter. Using this system, we detected mir-9-2 as one of the most efficient targets. We also identified a novel DGCR8-responsive RNA element, which is highly conserved among mammalian species and could be regulated at the epi-transcriptome (RNA modification) level. This unique feature between DGCR8 and pri-miR-9-2 processing may suggest a link to the risk of schizophrenia.

DGCR5 is activated by PAX5 and promotes pancreatic cancer via targeting miR-3163/TOP2A and activating Wnt/β-catenin pathway.

Long noncoding RNA DiGeorge syndrome critical region gene 5 (DGCR5) has been shown to be highly associated with cancer development. However, the biological role and molecular mechanism of DGCR5 in pancreatic cancer (PC) remains largely unknown. This study aimed to explore the role of DGCR5 in PC. It was revealed that DGCR5 was highly expressed in PC tissues compared with adjacent normal tissues and was associated with poor prognosis in PC patients. Furthermore, DGCR5 depletion inhibited the proliferation, migration and invasion by increasing apoptosis and inducing G0/G1 cell cycle arrest in vitro. Moreover, xenograft assay validated that DGCR5 promotes PC tumor growth in vivo. Mechanistically, DGCR5 was found to act as a ceRNA by sponging miR-3163 to regulate DNA topoisomerase 2-alpha (TOP2A) and inhibit Wnt/β-catenin pathway. In addition, it was found that DGCR5 downregulation could enhance the sensitivity of PC cells to gemcitabine, and ChIP assay showed that PAX5 (Paired Box 5) could bind to the promoter region of DGCR5 and increase its transcription. The results of the present study indicated that DGCR5 may be a potential diagnostic biomarker and therapeutic target for PC.

CtIP suppresses primary microRNA maturation and promotes metastasis of colon cancer cells in a xenograft mouse model

miRNAs are important regulators of eukaryotic gene expression. The post-transcriptional maturation of miRNAs is controlled by the Drosha-DiGeorge syndrome critical region gene 8 (DGCR8) microprocessor. Dysregulation of miRNA biogenesis has been implicated in the pathogenesis of human diseases, including cancers. C-terminal–binding protein–interacting protein (CtIP) is a well-known DNA repair factor that promotes the processing of DNA double-strand break (DSB) to initiate homologous recombination–mediated DSB repair. However, it was unclear whether CtIP has other unknown cellular functions. Here, we aimed to uncover the roles of CtIP in miRNA maturation and cancer cell metastasis. We found that CtIP is a potential regulatory factor that suppresses the processing of miRNA primary transcripts (pri-miRNA). CtIP directly bound to both DGCR8 and pri-miRNAs through a conserved Sae2-like domain, reduced the binding of Drosha to DGCR8 and pri-miRNA substrate, and inhibited processing activity of Drosha complex. CtIP depletion significantly increased the expression levels of a subset of mature miRNAs, including miR-302 family members that are associated with tumor progression and metastasis in several cancer types. We also found that CtIP-inhibited miRNAs, such as miR-302 family members, are not crucial for DSB repair. However, increase of miR-302b levels or loss of CtIP function severely suppressed human colon cancer cell line tumor cell metastasis in a mouse xenograft model. These studies reveal a previously unrecognized mechanism of CtIP in miRNA processing and tumor metastasis that represents a new function of CtIP in cancer.

DGCR8/miR-106 Axis Enhances Radiosensitivity of Head and Neck Squamous Cell Carcinomas by Downregulating RUNX3

Purpose: Head and neck squamous cell carcinoma (HNSCC) is the sixth most prevalent malignant tumor worldwide, and the radiotherapy effect is strongly associated with human papillomavirus (HPV) infection. Therefore, the aim of our study was to analyze the mechanism of HPV E7 and its effects on radiosensitivity in HNSCC cells.Methods: The mRNA expression of DiGeorge syndrome critical region gene 8 (DGCR8), has-miR-106a, and Runt-related transcription factor 3 (RUNX3) was examined by quantitative real-time PCR (RT-qPCR). The protein expression of DGCR8, E7, RUNX3, caspase-3/cleaved caspase-3, poly(ADP-ribose) polymerase (PARP)/cleaved PARP, and γH2AX was measured by Western blot. The expression level of DGCR8 was measured by immunofluorescence assay. Starbase database (http://starbase.sysu.edu.cn/) was used to analyze the correlation between has-miR-106a-5p and DGCR8. TargetScan database (http://www.targetscan.org/vert_72/) was adopted to calculate the prediction of binding sites. Radiosensitivity was evaluated through clone formation assays and Cell Counting Kit-8 (CCK-8) assays.Results: In our study, we found that the mRNA and protein expression levels of HPV E7 and DGCR8 in HPV-positive HNSCC cells were higher than those in HPV-negative cells. The expression of DGCR8 was increased in FaDu and UM-SCC-4 with E7 overexpression, while the expression of DGCR8 was decreased in UM-SCC-47 and UPCI-SCC-090 with E7 silence. The miR-106a expression was increased after DGCR8 overexpression in FaDu and UM-SCC-4. However, the miR-106a expression was decreased in UM-SCC-47 and UPCI-SCC-090 with E7 silence. In radiation conditions, clone formation assays found that less clones formed in FaDu and UM-SCC-4 cells subsequent to silencing DGCR8 or miR-106a than that in the control group, and more clones were formed in UM-SCC-47 and UPCI-SCC-090 cells overexpressing DGCR8 or miR-106a than that in the control group. Luciferase reporter gene assays verified that miR-106a targeted the 3′ untranslated region (UTR) of RUNX3 mRNA. MiR-106a overexpression resulted in a decrease in RUNX3 expression, and miR-106a silence increased RUNX3 expression. Rescue experiments conducted with miR-106a inhibitor restored radiation resistance and reduced DNA damage in radiation condition.Conclusions: Our study indicated that HPV E7 activated DGCR8/miR-106a/RUNX3 axis to enhance radiation sensitivity and provided directions for targeted therapeutic interventions.

Deficient Expression of DGCR8 in Human Testis is Related to Spermatogenesis Dysfunction, Especially in Meiosis I.

IntroductionDiGeorge syndrome critical region gene 8 (DGCR8) contributes to miRNA biogenesis, and defects in its expression could lead to defects in spermatogenesis.MethodsHere, we assess gene and protein expression levels of DGCR8 in the testicular biopsy specimens obtained from men with obstructive azoospermia (OA, n = 19) and various types of non-obstructive azoospermia (NOA) including maturation arrest (MA, n = 17), Sertoli cell-only syndrome (SCOS, n = 20) and hypospermatogenesis (HYPO, 18). Also, samples of men with NOA were divided into two groups based on successful and unsuccessful sperm recovery, NOA+ in 21 patients and NOA− in 34 patients.ResultsExaminations disclosed a severe decrease in DGCR8 in samples with MA and SCOS in comparison to OA samples (P < 0.001). Also, the results showed DGCR8 has significantly lower expression in testis tissues of NOA− group in comparison to NOA+ group (p<0.05). Western blot analysis confirmed that the DGCR8 protein was not expressed in SCOS samples and had a very low expression in MA and HYPO samples.DiscussionThe results of this survey showed that DGCR8 is an important gene for the entire spermatogenesis pathway. Moreover, DGCR8 gene plays an important role in the diagnosis of NOA subgroups, and also the expression changes in it might contribute to SCOS or MA phenotypes. This gene with considering other related genes can also be a predictor of sperm retrieval.

Integrative Analysis of NSCLC Identifies LINC01234 as an Oncogenic lncRNA that Interacts with HNRNPA2B1 and Regulates miR-106b Biogenesis.

The discovery of long noncoding RNAs (lncRNAs) has increased our understanding of the development and progression of many cancers, but their contributions to non-small cell lung cancer (NSCLC) remain poorly understood. Here, we profiled lncRNA expression in NSCLC and investigated in detailthe molecular function of one upregulated lncRNA, LINC01234. LINC01234 was overexpressed in NSCLC compared with normal lung tissue and correlated positively with poor prognosis. Downregulation of LINC01234 impaired cell proliferation invitro and tumor growth invivo. RNA pull-down/mass spectrometry experiments showed that LINC01234 interacted with the RNA-binding protein heterogeneous nuclear ribonucleoprotein A2/B1 (HNRNPA2B1), which, in turn, led to the recruitment of DiGeorge syndrome critical region gene 8 (DGCR8), a subunit of the microRNA (miRNA) microprocessor complex. Accordingly, depletion of either LINC01234 or HNRNPA2B1 reduced the processing of several miRNA precursors, including primary microRNA (pri-miR)-106b. miR-106b-5p enhanced NSCLC cell growth by downregulating cryptochrome 2 (CRY2), thereby increasing c-Myc expression. Finally, we found that activated c-Myc binds to the LINC01234 promoter to increase its transcription, creating a c-Myc-LINC01234-HNRNPA2B1-miR-106b-5p-CRY2-c-Myc positive-feedback loop. We identified numerous lncRNAs with dysregulated expression in NSCLC and demonstrated a novel oncogenic axis involving LINC01234, HNRNPA2B1, miR-106b-5p, CRY2, and c-Myc. Components of this axis may be potential novel targets for NSCLC.