SMG1 acts as a novel potential tumor suppressor with epigenetic inactivation in acute myeloid leukemia

Cell death-associated lncRNAs in cancer immunopathogenesis: An exploration of molecular mechanisms and signaling pathways

Cancer remains one of the foremost causes of mortality worldwide, highlighting the urgent need for novel therapeutic targets due to the insufficient efficacy and adverse side effects associated with existing cancer treatments. Long non-coding RNAs (lncRNAs), defined as RNA transcripts longer than 200 nucleotides, have emerged as pivotal regulators in the initiation and progression of various malignancies. In oncology, programmed cell death (PCD) serves as the primary mechanism for tumor cell elimination, comprising processes such as apoptosis, pyroptosis, autophagy, and ferroptosis. Recent studies have elucidated a substantial relationship between lncRNAs and these PCD pathways, indicating that lncRNAs can modulate the apoptotic and non-apoptotic death mechanisms. This regulation may influence not only the dynamics of cancer progression but also the therapeutic response to clinical interventions. This review delves into the intricate role of lncRNAs within the context of PCD in cancer, unveiling the underlying pathogenic mechanisms while proposing innovative strategies for cancer therapy. Additionally, it discusses the potential therapeutic implications of targeting lncRNAs in PCD and related signaling pathways, aiming to enhance treatment outcomes for patients facing cancer.

LncRNAs and regulated cell death in tumor cells

Regulated Cell Death (RCD) is a mode of cell death that occurs through drug or genetic intervention. The regulation of RCDs is one of the significant reasons for the long survival time of tumor cells and poor prognosis of patients. Long non-coding RNAs (lncRNAs) which are involved in the regulation of tumor biological processes, including RCDs occurring on tumor cells, are closely related to tumor progression. In this review, we describe the mechanisms of eight different RCDs which contain apoptosis, necroptosis, pyroptosis, NETosis, entosis, ferroptosis, autosis and cuproptosis. Meanwhile, their respective roles in the tumor are aggregated. In addition, we outline the literature that is related to the regulatory relationships between lncRNAs and RCDs in tumor cells, which is expected to provide new ideas for tumor diagnosis and treatment.

Curcumin as a therapeutic agent in cancer therapy: Focusing on its modulatory effects on circular RNAs

Curcumin, a natural polyphenol compound, has been identified as an effective therapeutic agent against cancer that exerts its anti-tumor activities by up/downregulating signaling mediators and modulating various cellular processes, including angiogenesis, autophagy, apoptosis, metastasis, and epithelial-mesenchymal transition (EMT). Since almost 98% of genomic transcriptional production is noncoding RNAs in humans, there is evidence that curcumin exerts therapeutic effects through the alterations of noncoding RNAs in various types of cancers. Circular RNAs (circRNAs) are formed by the back-splicing of immature mRNAs and have several functions, including functioning as miRNA sponges. It has been shown that curcumin modulated various circRNAs, including circ-HN1, circ-PRKCA, circPLEKHM3, circZNF83, circFNDC3B, circ_KIAA1199, circRUNX1, circ_0078710, and circ_0056618. The modulation of these circRNAs targeted the expression of mRNAs and modified various signaling pathways and hallmarks of cancer. In this article, we reviewed the pharmacokinetics of curcumin, its anti-cancer activities, as well as the biology and structure of circRNAs. Our main focus was on how curcumin exerts anti-cancer functions by modulating circRNAs and their target mRNAs and pathways.

Aberrant DNA Methylation Status and mRNA Expression Level of SMG1 Gene in Chronic Myeloid Leukemia: A Case-Control Study

OObjective: Chronic myeloid leukemia (CML) is a myeloproliferative malignancy with different stages. Aberrant epigenetic modifications, such as DNA methylation, have been introduced as a signature for diverse cancers which also plays a crucial role in CML pathogenesis and development. Suppressor with morphogenetic effect on genitalia (SMG1) gene recently has been brought to the spotlight as a potent tumor suppressor gene that can be suppressed by tumors for further progress. The present study aims to investigate SMG1 status in CML patients.

MATERIALS AND METHODS

In this case-control study, peripheral blood from 30 patients with different phases of CML [new case (N)=10, complete molecular remission (CMR)=10, blastic phase (BP)=10] and 10 healthy subjects were collected. Methylation status and expression level of SMG1 gene promoter was assessed by methylation-specific polymerase chain reaction (MSP) and quantitative reverse-transcription PCR, respectively.

RESULTS

MSP results of SMG1 gene promotor in the new case group were methylated (60% methylated, 30% hemimethylated and 10% unmethylated). All CMR and control group patients were unmethylated in the SMG1 gene promoter. In the BP group, methylated SMG1 promoter was seen (50% of patients had a methylated status and 50% had hemimethylated status). In comparison with the healthy subjects, expression level of SMG1 in the new case group was decreased (P<0.01); in the CMR group and BP-CML groups, it was increased (P<0.05). No significant correlation between patients' hematological features and SMG1 methylation was seen.

CONCLUSION

Our results demonstrated that aberrant methylation of SMG1 occurred in CML patients and it had a significant association with SMG1 expression. SMG1 gene promoter showed diverse methylated status and subsequent expression levels in different phases of CML. These findings suggested possible participation of SMG1 suppression in the CML pathogenesis.

DNA and RNA Binding Proteins: From Motifs to Roles in Cancer

DNA and RNA binding proteins (DRBPs) are a broad class of molecules that regulate numerous cellular processes across all living organisms, creating intricate dynamic multilevel networks to control nucleotide metabolism and gene expression. These interactions are highly regulated, and dysregulation contributes to the development of a variety of diseases, including cancer. An increasing number of proteins with DNA and/or RNA binding activities have been identified in recent years, and it is important to understand how their activities are related to the molecular mechanisms of cancer. In addition, many of these proteins have overlapping functions, and it is therefore essential to analyze not only the loss of function of individual factors, but also to group abnormalities into specific types of activities in regard to particular cancer types. In this review, we summarize the classes of DNA-binding, RNA-binding, and DRBPs, drawing particular attention to the similarities and differences between these protein classes. We also perform a cross-search analysis of relevant protein databases, together with our own pipeline, to identify DRBPs involved in cancer. We discuss the most common DRBPs and how they are related to specific cancers, reviewing their biochemical, molecular biological, and cellular properties to highlight their functions and potential as targets for treatment.

Methylation and Expression Status of The CpG-Island of SMG1 Promoter in Acute Myeloid Leukemia: A Follow-Up Study in Patients

Objective

Aberrant alterations in DNA methylation are known as one of the hallmarks of oncogenesis and play a vital role in the progression of acute myeloid leukemia (AML). SMG1 is a member of the Phosphoinositide 3-kinases family, acting as a tumor suppressor gene. The aim of this study was the evaluation of the expression level and methylation status of SMG1 in AML.

Materials and Methods

In this follow-up study on AML patients admitted to Shariati Hospital, Tehran, Iran, the methylation status of SMG1 [performed by methylation-specific polymerase chain reaction (PCR)] and its expression level (performed by qRT-PCR) were evaluated in three phases: newly diagnosed, under treatment and complete remission. The correlation of the methylation status of SMG1, its expression level, and clinical/paraclinical data was analyzed by SPSS ver.25.

Results

This study on 18 patients and five control individuals showed that the CpG-islands of the SMG1 promoter in newly diagnosed cases is hypomethylated compared to the normal group (P=0.002) The fold change of SMG1 expression levels in new cases is 0.464 ± 0.468, while the fold change of SMG1 expression levels in under-treatment and in-remission patients is 0.973 ± 1.159 and 0.685 ± 0.885, respectively. In under-treatment patients, white blood cell (WBC) count decreases 114176.36 cell/μl with each unit of increase in fold change of SMG1 (P<0.0001), and Hb unit increases 2.062 g/dl with each unit of increase in fold change (P<0.0001). Also, in the remission phase, the Hb unit increases 1.395 g/dl with each unit increase in fold change (P=0.019).

Conclusion

The robust results of our study suggest that the methylation and expression of have a high impact on the pathogenesis of AML. Also, the methylation and expression of SMG1 can play a prognostic role in AML.

Discriminating Potential Genetic Markers for Complete Response and Non-Complete Response Patients to Neoadjuvant Chemotherapy with Locally Advanced Rectal Cancer

Background: Neoadjuvant chemoradiotherapy (nCRT) prior to surgery is considered standard therapy for locally advanced rectal cancer. Unfortunately, most patients with rectal cancer are resistant to radiotherapy. This might be a genetic cause. The role of certain rectal cancer-causing genes has not been completely elucidated. This study aims to investigate the genes responsible for locally advanced rectal cancer patients not reacting to radiotherapy. Methods: Whole exome sequencing of the DNA samples was performed on the samples. Bioinformatic analysis on the subjects was established. Individual genetic information was screened to identify differently expressed genes that more frequently appeared in non-complete response (NCR) compared to complete response (CR) patients after nCRT. All variations were verified by Sanger sequencing. Results: Genotyping information and pathway analyses of the samples indicated genes such as FLCN, CALML5, and ANTXR1 to be commonly mutated in CR group, whereas genes such as GALNTL14, CNKSR1, ACD, and CUL3 were more commonly mutated in the NCR group. Chi-square test revealed some significant variants (<0.05) such as rs3744124 (FLCN), rs28365986 (ANTXR1), rs10904516 (CALML5), rs3738952 (CUL3), rs13394 and rs2293013 (PIH1D1), rs2274531 (GPA33), rs4963048 (BRSK2), rs17883366 (IL3RA), rs2297575 (PSMD5), rs2288101 (GALNT14), and rs11954652 (DCTN4). Conclusion: Identifying an array of genes that separate NCRs from CRs would lead to finding genetic biomarkers for early detection of rectal cancer patients that are resistant to nCRT. A further investigation to validate the significance of genetic biomarkers to segregate NCRs from CRs should be performed with a larger CRC dataset. Protein expression levels, as well as transcriptomic analysis, would also help us understand the mechanism of how these genes could play a role in preventing radiation therapy to patients. This would be essential to prevent redundant radiation therapy.

Curcumin inhibits ovarian cancer progression by regulating circ-PLEKHM3/miR-320a/SMG1 axis

BACKGROUND

Curcumin has a potential therapeutic role in ovarian cancer. However, whether curcumin plays anti-cancer role in ovarian cancer by mediating the circular RNA (circRNA)/microRNA (miRNA)/mRNA network is still unclear.

METHODS

The expression of circ-PLEKHM3, miR-320a, and suppressor of morphogenesis in genitalia 1 (SMG1) was detected via qRT-PCR. Cell viability, colony-formation ability and apoptosis were analyzed via cell counting kit-8 assay, colony formation analysis, and flow cytometry. Protein expression was measured using western blot. The in vivo experiments were performed using a xenograft model. Target association was evaluated via dual-luciferase reporter analysis and RIP assay.

RESULTS

Curcumin suppressed ovarian cancer cell proliferation and promoted apoptosis. Circ-PLEKHM3 was downregulated in ovarian cancer, and its expression could be promoted by curcumin treatment. Circ-PLEKHM3 overexpression exacerbated the effect of curcumin on ovarian cancer cell proliferation and apoptosis, as well as anti-tumor effect. MiR-320a was targeted by circ-PLEKHM3. The inhibition effect of circ-PLEKHM3 overexpression on cell proliferation and the enhancing effect on cell apoptosis could be reversed by miR-320a mimic. SMG1 was targeted by miR-320a, and its knockdown also reversed the regulation of miR-320a inhibitor on the proliferation and apoptosis of ovarian cancer cells. In addition, circ-PLEKHM3 could upregulate SMG1 expression via sponging miR-320a.

CONCLUSION

Curcumin restrained proliferation and facilitated apoptosis in ovarian cancer by regulating the circ-PLEKHM3/miR-320a/SMG1 axis.

Circular RNA CircPPP1CB Suppresses Tumorigenesis by Interacting With the MiR-1307-3p/SMG1 Axis in Human Bladder Cancer

Circular RNA (circRNA) is a newly discovered endogenous non-coding RNA (ncRNA), which is characterized with a closed circular structure. A growing body of evidence has verified the vital roles of circRNAs in human cancer. In this research, we selected circPPP1CB as a study object by circRNA sequencing and quantitative real-time PCR (qRT-PCR) validation in human bladder cancer (BC). CircPPP1CB is downregulated in BC and is negatively correlated with clinical stages and histological grades. Functionally, circPPP1CB modulated cell growth, metastasis, and epithelial-to-mesenchymal transition (EMT) process in vitro and in vivo. Mechanically, we performed various experiments to verify the circPPP1CB/miR-1307-3p/SMG1 regulatory axis. Taken together, our results demonstrated that circPPP1CB participates in tumor growth, metastasis, and EMT process by interacting with the miR-1307-3p/SMG1 axis, and that circPPP1CB might be a novel therapeutic target and diagnostic biomarker in human BC.

The pioneer transcription factors Foxa1 and Foxa2 regulate alternative RNA splicing during thymocyte positive selection

During positive selection at the transition from CD4+CD8+ double-positive (DP) to single-positive (SP) thymocyte, TCR signalling results in appropriate MHC restriction and signals for survival and progression. We show that the pioneer transcription factors Foxa1 and Foxa2 are required to regulate RNA splicing during positive selection of mouse T cells and that Foxa1 and Foxa2 have overlapping/compensatory roles. Conditional deletion of both Foxa1 and Foxa2 from DP thymocytes reduced positive selection and development of CD4SP, CD8SP and peripheral naïve CD4+ T cells. Foxa1 and Foxa2 regulated the expression of many genes encoding splicing factors and regulators, including Mbnl1, H1f0, Sf3b1, Hnrnpa1, Rnpc3, Prpf4b, Prpf40b and Snrpd3. Within the positively selecting CD69+DP cells, alternative RNA splicing was dysregulated in the double Foxa1/Foxa2 conditional knockout, leading to >850 differentially used exons. Many genes important for this stage of T-cell development (Ikzf1-3, Ptprc, Stat5a, Stat5b, Cd28, Tcf7) and splicing factors (Hnrnpab, Hnrnpa2b1, Hnrnpu, Hnrnpul1, Prpf8) showed multiple differentially used exons. Thus, Foxa1 and Foxa2 are required during positive selection to regulate alternative splicing of genes essential for T-cell development, and, by also regulating splicing of splicing factors, they exert widespread control of alternative splicing.

Circular RNA VMA21 ameliorates sepsis-associated acute kidney injury by regulating miR-9-3p/SMG1/inflammation axis and oxidative stress

Accumulating evidence suggests that circular RNAs have the abilities to regulate gene expression during the progression of sepsis‐associated acute kidney injury. Circular RNA VMA21 (circVMA21), a recent identified circular RNA, could reduce apoptosis to alleviate intervertebral disc degeneration in rats and protect WI‐38 cells from lipopolysaccharide‐induced injury. However, the role of circVMA21 in sepsis‐associated acute kidney injury (sepsis‐associated AKI) is unknown. In this study, we first demonstrated that circVMA21 alleviated sepsis‐associated AKI by reducing apoptosis and inflammation in rats and HK‐2 cells. Additionally, to explore the molecule mechanism underlying the amelioration, after the bioinformatics analysis, we confirmed that miR‐9‐3p directly bound to circVMA21 by luciferase and RNA immunoprecipitation assay, and the effector protein of miR‐9‐3p was SMG1. Furthermore, the oxidative stress caused by sepsis‐associated AKI was down‐regulated by circVMA21. In conclusion, circVMA21 plays an important role in the regulating sepsis‐associated AKI via adjusting miR‐9‐39/SMG1/inflammation axis and oxidative stress.

MicroRNA-32 promotes ovarian cancer cell proliferation and motility by targeting SMG1

Ovarian cancer (OC) is the most lethal gynecological malignancy and one of the leading causes of cancer-related deaths among women. Metastasis is the main cause of poor prognosis in OC. MicroRNA (miRNA/miR) has been shown to play an important role in tumorigenesis and metastasis in various cancer types by affecting the expression of its targets. In the present study, the role of miR-32 (miR-32-5p) in OC was explored. Reverse transcription-quantitative PCR results showed that miR-32 expression was significantly upregulated in both OC tissues and cell lines. Inhibition of miR-32 by transfection with miR-32 inhibitor in OC cells markedly suppressed cell proliferation, migration and invasion. In addition, a luciferase assay showed that suppressor of morphogenesis in genitalia 1 (SMG1) is a direct target of miR-32, and interference in SMG1 expression with transfection of SMG1 small hairpin RNA restored miR-32-mediated OC cell proliferation, migration and invasion. Taken together, these results indicate that miR-32 may promote OC cell growth and motility by targeting SMG1. The data of the present study suggest that miR-32 may serve as a potential therapeutic target for OC treatment in the future.

Nonsense-mediated RNA Decay Pathway Inhibition Restores Expression and Function of W1282X CFTR

The recessive genetic disease cystic fibrosis (CF) is caused by loss-of-function mutations in the CFTR (CF transmembrane conductance regulator) gene. Approximately 10% of patients with CF have at least one allele with a nonsense mutation in CFTR. Nonsense mutations generate premature termination codons that can subject mRNA transcripts to rapid degradation through the nonsense-mediated mRNA decay (NMD) pathway. Currently, there are no approved therapies that specifically target nonsense mutations in CFTR. Here, we identified antisense oligonucleotides (ASOs) that target the NMD factor SMG1 to inhibit the NMD pathway, and determined their effects on the W1282X CFTR mutation. First, we developed and validated two in vitro models of the W1282X CFTR mutation. Next, we treated these cells with antisense oligonucleotides to inhibit NMD and measured the effects of these treatments on W1282X expression and function. SMG1-ASO-mediated NMD inhibition upregulated the RNA, protein, and surface-localized protein expression of the truncated W1282X gene product. Additionally, these ASOs increased the CFTR chloride channel function in cells homozygous for the W1282X mutation. Our approach suggests a new therapeutic strategy for patients harboring nonsense mutations and may be beneficial as a single agent in patients with CF and the W1282X mutation.

Analysis of TET2 and EZH2 gene functions in chromosome instability in acute myeloid leukemia

TET2 and EZH2 play important roles in the epigenetic regulation in many cancers. However, their specific roles in acute myeloid leukemia (AML) pathogenesis remain unknown. Here, the expression, methylation or mutation of EZH2 and TET2 was determined and further correlated with the levels of the chromosome instability (CIN) genes MAD2 and CDC20. We down-regulated EZH2 and TET2 in AML cell lines and assessed the effect on CIN using fluorescence in situ hybridization (FISH). Our results showed that TET2, EZH2, MAD2 and CDC20 were aberrantly expressed in AML patients. The expression level of MAD2 or CDC20 was positively correlated with that of TET2 or EZH2. Hypermethylation of the TET2 gene down-regulated its transcription. Down-regulation of EZH2 or TET2 expression inhibited apoptosis, affected MAD2 and CDC20 expression, and promoted CIN in AML cells. Decitabine treatment restored TET2 methylation and EZH2 transcription and ameliorated CIN in AML. Therefore, TET2 and EZH2 play a tumor-inhibiting role in AML that affects CIN via MAD2 and CDC20.

MicroRNA-18a promotes cancer progression through SMG1 suppression and mTOR pathway activation in nasopharyngeal carcinoma

miR-18a has been reported to be upregulated in nasopharyngeal carcinoma (NPC) tissues by microarray assays. However, the roles and the underlying mechanisms of miR-18a in NPC remain poorly understood. Here we demonstrated by real-time RT-PCR that miR-18a expression is upregulated in NPC tissues, and positively correlated with tumor size and TNM stage. Moreover, miR-18a expression could be upregulated by NF-κB activation or Epstein-Barr virus encoded latent membrane protein 1 expression. The ectopic expression of miR-18a promoted NPC cell proliferation, migration and invasion, while the repression of miR-18a had opposite effects. Candidate genes under regulation by miR-18a were screened out through a whole-genome microarray assay, further identified by a reporter assay and verified in clinical samples. SMG1, a member of the phosphoinositide 3-kinase-related kinases family and an mTOR antagonist, was identified as functional target of miR-18a. Our results confirmed that miR-18a exerts its oncogenic role through suppression of SMG1 and activation of mTOR pathway in NPC cells. Importantly, in vivo xenograft tumor growth in nude mice was effectively inhibited by intratumor injection of miR-18a antagomir. Our data support an oncogenic role of miR-18a through a novel miR-18a/SMG1/mTOR axis and suggest that the antitumor effects of antagomir-18a may make it suitable for NPC therapy.

SMG1 heterozygosity exacerbates haematopoietic cancer development in Atm null mice by increasing persistent DNA damage and oxidative stress

Suppressor of morphogenesis in genitalia 1 (SMG1) and ataxia telangiectasia mutated (ATM) are members of the PI3‐kinase like–kinase (PIKK) family of proteins. ATM is a well‐established tumour suppressor. Loss of one or both alleles of ATM results in an increased risk of cancer development, particularly haematopoietic cancer and breast cancer in both humans and mouse models. In mice, total loss of SMG1 is embryonic lethal and loss of a single allele results in an increased rate of cancer development, particularly haematopoietic cancers and lung cancer. In this study, we generated mice deficient in Atm and lacking one allele of Smg1, Atm^−/−Smg1^gt/+ mice. These mice developed cancers more rapidly than either of the parental genotypes, and all cancers were haematopoietic in origin. The combined loss of Smg1 and Atm resulted in a higher level of basal DNA damage and oxidative stress in tissues than loss of either gene alone. Furthermore, Atm^−/−Smg1^gt/+ mice displayed increased cytokine levels in haematopoietic tissues compared with wild‐type animals indicating the development of low‐level inflammation and a pro‐tumour microenvironment. Overall, our data demonstrated that combined loss of Atm expression and decreased Smg1 expression increases haematopoietic cancer development.

LncRNA MAGI2-AS3 inhibits hepatocellular carcinoma cell proliferation and migration by targeting the miR-374b-5p/SMG1 signaling pathway

Long noncoding RNAs (lncRNAs) have been proven to play critical roles in cancer progression. Recently, lncRNA MAGI2-AS3 has been revealed to be a tumor suppressor and inhibit cell growth by targeting the Fas/FasL signalling pathway in breast cancer. However, the role and underlying mechanism of MAGI2-AS3 in hepatocellular carcinoma (HCC) remain largely unknown. In the current study, we found that MAGI2-AS3 expression is downregulated in HCC tissues and closely associated with some clinical characteristics (tumor size, lymph node metastasis, and TNM stage) and poor overall survival. Overexpression of MAGI2-AS3 inhibits HCC cell proliferation and migration in vitro, while impedes tumor growth in vivo accordantly. In addition, our data suggest that MAGI2-AS3 could function as an endogenous sponge of miR-374b-5p by directly binding to it and suppressing its expression. Furthermore, miR-374b-5p upregulation could restore the inhibitory effect of MAGI2-AS3 on HCC cells processes. Moreover, suppressor with morphogenetic effect on genitalia family member 1 (SMG1) is positively regulated by MAGI2-AS3 via absorbing miR-374b-5p in HCC cells. More important, SMG1 knockdown reverses the suppressive function of MAGI2-AS3 in HCC cell processes. Taken together, we reveal a functional MAGI2-AS3/miR-374b-5p/SMG1 axis that suppresses HCC progression, potently suggesting a new road for HCC treatment.

The Capacity of Long-Term in Vitro Proliferation of Acute Myeloid Leukemia Cells Supported Only by Exogenous Cytokines Is Associated with a Patient Subset with Adverse Outcome

Acute myeloid leukemia (AML) is an aggressive malignancy, which is highly heterogeneous with regard to chemosensitivity and biological features. The AML cell population is organized in a hierarchy that is reflected in the in vitro growth characteristics, with only a minority of cells being able to proliferate for more than two weeks. In this study, we investigated the ability of AML stem cells to survive and proliferate in suspension cultures in the presence of exogenous mediators but without supporting non-leukemic cells. We saw that a high number of maintained stem cells (i.e., a large number of clonogenic cells after five weeks of culture) was associated with decreased overall survival for patients receiving intensive chemotherapy; this prognostic impact was also detected in the multivariate/adjusted analysis. Furthermore, the patients with many clonogenic cells presented more frequently with mutations in transcription-related genes, and also showed a higher abundance of proteins involved in transcription at the time of diagnosis. In conclusion, the growth characteristics of the long-term proliferating leukemic stem cells seem to have an independent prognostic impact in human AML, and these characteristics appear to be reflected by the mutational landscape and the proteome of the patients at the time of diagnosis.

Transcriptome-wide analysis uncovers the targets of the RNA-binding protein MSI2 and effects of MSI2's RNA-binding activity on IL-6 signaling

The RNA-binding protein Musashi 2 (MSI2) has emerged as an important regulator in cancer initiation, progression, and drug resistance. Translocations and deregulation of the MSI2 gene are diagnostic of certain cancers, including chronic myeloid leukemia (CML) with translocation t(7;17), acute myeloid leukemia (AML) with translocation t(10;17), and some cases of B-precursor acute lymphoblastic leukemia (pB-ALL). To better understand the function of MSI2 in leukemia, the mRNA targets that are bound and regulated by MSI2 and their MSI2-binding motifs need to be identified. To this end, using photoactivatable ribonucleoside cross-linking and immunoprecipitation (PAR-CLIP) and the multiple EM for motif elicitation (MEME) analysis tool, here we identified MSI2's mRNA targets and the consensus RNA-recognition element (RRE) motif recognized by MSI2 (UUAG). Of note, MSI2 knockdown altered the expression of several genes with roles in eukaryotic initiation factor 2 (eIF2), hepatocyte growth factor (HGF), and epidermal growth factor (EGF) signaling pathways. We also show that MSI2 regulates classic interleukin-6 (IL-6) signaling by promoting the degradation of the mRNA of IL-6 signal transducer (IL6ST or GP130), which, in turn, affected the phosphorylation statuses of signal transducer and activator of transcription 3 (STAT3) and the mitogen-activated protein kinase ERK. In summary, we have identified multiple MSI2-regulated mRNAs and provided evidence that MSI2 controls IL6ST activity that control oncogenic signaling networks. Our findings may help inform strategies for unraveling the role of MSI2 in leukemia to pave the way for the development of targeted therapies.

SMG-1 inhibition by miR-192/-215 causes epithelial-mesenchymal transition in gastric carcinogenesis via activation of Wnt signaling

SMG‐1,a member of the phosphoinositide kinase‐like kinase family, functioned as a tumor suppressor gene. However, the role of SMG‐1 in GC remain uncharacterized. In this study, regulation of SMG‐1 by miR‐192 and‐215, along with the biological effects of this modulation, were studied in GC. We used gene microarrays to screening and luciferase reporter assays were to verify the potential targets of miR‐192 and‐215. Tissue microarrays analyses were applied to measure the levels of SMG‐1 in GC tissues. Western blot assays were used to assess the signaling pathway of SMG‐1 regulated by miR‐192 and‐215 in GC. SMG‐1 was significantly downregulated in GC tissues.The proliferative and invasive properties of GC cells were decreased by inhibition of miR‐192 and‐215, whereas an SMG‐1siRNA rescued the inhibitory effects. Finally, SMG‐1 inhibition by miR‐192 and‐215 primed Wnt signaling and induced EMT. Wnt signaling pathway proteins were decreased markedly by inhibitors of miR‐192 and‐215, while SMG‐1 siRNA reversed the inhibition apparently. Meanwhile, miR‐192 and‐215 inhitibtors increased E‐cadherin expression and decreased N‐cadherin and cotransfection of SMG‐1 siRNA reversed these effects. In summary, these findings illustrate that SMG‐1 is suppressed by miR‐192 and‐215 and functions as a tumor suppressor in GC by inactivating Wnt signaling and suppressing EMT.

A 16-gene signature predicting prognosis of patients with oral tongue squamous cell carcinoma

Background

Oral tongue squamous cell carcinoma (OTSCC) is the most common subtype of oral cancer. A predictive gene signature is necessary for prognosis of OTSCC.

Methods

Five microarray data sets of OTSCC from the Gene Expression Omnibus (GEO) and one data set from The Cancer Genome Atlas (TCGA) were obtained. Differentially expressed genes (DEGs) of GEO data sets were identified by integrated analysis. The DEGs associated with prognosis were screened in the TCGA data set by univariate survival analysis to obtain a gene signature. A risk score was calculated as the summation of weighted expression levels with coefficients by Cox analysis. The signature was used to distinguish carcinoma, estimated by receiver operator characteristic curves and the area under the curve (AUC). All were validated in the GEO and TCGA data sets.

Results

Integrated analysis of GEO data sets revealed 300 DEGs. A 16-gene signature and a risk score were developed after survival analysis. The risk score was effective to stratify patients into high-risk and low-risk groups in the TCGA data set (P < 0.001). The 16-gene signature was valid to distinguish the carcinoma from normal samples (AUC 0.872, P < 0.001).

Discussion

We identified a useful 16-gene signature for prognosis of OTSCC patients, which could be applied to clinical practice. Further studies were needed to prove the findings.

Anthocyanins from black rice (Oryza sativa) promote immune responses in leukemia through enhancing phagocytosis of macrophages in vivo

Rice is a staple food in numerous countries around the world. Anthocyanins found in black rice have been reported to reduce the risk of certain diseases, but the effects of crude extract of anthocyanins from Asia University-selected purple glutinous indica rice (AUPGA) on immune responses have not yet been demonstrated. The current study aimed to investigate whether AUPGA treatment could affect immune responses in murine leukemia cells in vivo. Murine acute myelomonocytic leukemia WEHI-3 cells were intraperitoneally injected into normal BALB/c mice to generate leukemia mice. A total of 50 mice were randomly divided into five groups (n=10 in each group) and were fed a diet supplemented with AUPGA at 0, 20, 50 or 100 mg/kg for three weeks. All mice were weighed and the blood, liver and spleen were collected for further experiments. The results indicated that AUPGA did not significantly affect animal body weight, but significantly increased spleen weight (P<0.05) and decreased liver weight (P<0.05) when compared with the control group. AUPGA significantly increased the T cell (CD3) population at treatments of 20 and 100 mg/kg (P<0.05). However, it only significantly increased the B cell (CD19) population at a treatment of 20 mg/kg (P<0.05). Furthermore, AUPGA at 50 and 100 mg/kg significantly increased the monocyte (CD11b) population and the level of macrophages (Mac-3; P<0.05 for both). AUPGA at 50 and 100 mg/kg significantly promoted macrophage phagocytosis in peripheral blood mononuclear cells (P<0.05), and all doses of AUPGA treatment significantly promoted macrophage phagocytotic activity in the peritoneum (P<0.05). AUPGA treatment significantly decreased natural killer cell activity from splenocytes (P<0.05). Finally, AUPGA treatment at 20 mg/kg treatment significantly promoted T cell proliferation (P<0.05), and treatment at 50 and 100 mg/kg significantly decreased B cell proliferation compared with the control group (P<0.05).

Functional Genomics Identifies Tis21-Dependent Mechanisms and Putative Cancer Drug Targets Underlying Medulloblastoma Shh-Type Development

We have recently generated a novel medulloblastoma (MB) mouse model with activation of the Shh pathway and lacking the MB suppressor Tis21 (Patched1^+/-/Tis21^KO ). Its main phenotype is a defect of migration of the cerebellar granule precursor cells (GCPs). By genomic analysis of GCPs in vivo, we identified as drug target and major responsible of this defect the down-regulation of the promigratory chemokine Cxcl3. Consequently, the GCPs remain longer in the cerebellum proliferative area, and the MB frequency is enhanced. Here, we further analyzed the genes deregulated in a Tis21-dependent manner (Patched1^+/-/Tis21 wild-type vs. Ptch1^+/-/Tis21 knockout), among which are a number of down-regulated tumor inhibitors and up-regulated tumor facilitators, focusing on pathways potentially involved in the tumorigenesis and on putative new drug targets. The data analysis using bioinformatic tools revealed: (i) a link between the Shh signaling and the Tis21-dependent impairment of the GCPs migration, through a Shh-dependent deregulation of the clathrin-mediated chemotaxis operating in the primary cilium through the Cxcl3-Cxcr2 axis; (ii) a possible lineage shift of Shh-type GCPs toward retinal precursor phenotype, i.e., the neural cell type involved in group 3 MB; (iii) the identification of a subset of putative drug targets for MB, involved, among the others, in the regulation of Hippo signaling and centrosome assembly. Finally, our findings define also the role of Tis21 in the regulation of gene expression, through epigenetic and RNA processing mechanisms, influencing the fate of the GCPs.